US009376167B2(12) United States Patent(10) Patent No.:

Kawashima et al.

US 9,376,167 B2(45) Date of Patent:(54) FRICTIONAL RESISTANCE REDUCTION

Jun. 28, 2016(58) Field of Classification Search

CPC ................ B63B 1/38: B63B 2001/382: B63B

DEVICE FOR SHIP

2001/385; B63B 2001/387(75) Inventors: Hideki Kawashima, Tokyo (JP);Tetsugo Fukuda, Tokyo (JP); Yoshiaki
Kodama, Tokyo (JP); Munehiko
Hinatsu, Tokyo (JP); Toshifumi Hori,
Tokyo (JP); Masahiko Makino, Tokyo(JP); Kazuyoshi Harumi, Tokyo (JP);Masashi Ohnawa, Tokyo (JP); Haruya
Takeshi, Tokyo (JP); Tadanori
Takimoto, Tokyo (JP)(73) Assignee: NATIONAL MARITIMERESEARCH INSTITUTE, Tokyo (JP)(*) Notice:

Subject to any disclaimer, the term of thispatent is extended or adjusted under 35
U.S.C. 154(b) by 614 days.

USPC ............................................... 114/67 R, 67 A

See application file for complete search history.
(56)

References Cited
U.S. PATENT DOCUMENTS

4,380,893 A * 4/1983 Stokes et al. .................... 60/785
4,445,953. A

5, 1984 Hawk

(Continued)
FOREIGN PATENT DOCUMENTS
EP
EP

O650889 A1
O903287 A2

5, 1995
3, 1999(Continued)
OTHER PUBLICATIONS(21) Appl. No.:

12/935,624International Search Report for PCT Application No. PCT/JP2009/00.1520, May 19, 2009.

(22) PCT Filed:

Mar. 31, 2009(Continued)(86). PCT No.:

PCT/UP2009/OO1520

S371 (c)(1),(2), (4) Date:

Jul. 1, 2011(87) PCT Pub. No.: WO2009/122736
PCT Pub. Date: Oct. 8, 2009
(65)

Prior Publication Data

US 2011 FO25944O A1

Oct. 27, 2011

Primary Examiner — Andrew Polay(57)

ABSTRACTA inject gas control device that performs, for example, control reflecting variation in vessel velocity over time without
adversely affecting the main engine is realized. That is, it isprevented that gas is drawn too much and thereby a gas Supply
or charged air rate becomes insufficient, efficiency of themain engine is decreased and exhaust gas is deteriorated, andanalogous events occur because the gas Supply or charged air
rate is too much instead.

(30)

Foreign Application Priority Data

Apr. 1, 2008
Apr. 8, 2008
Apr. 8, 2008
Jul. 17, 2008
Mar. 27, 2009

(JP) ................................. 2008-095466(JP) ................................. 2008-100889(JP) ................................. 2008-10O894(JP) ................................. 2008-186588(JP) ................................. 2009-080676(51) Int. Cl.
B63B I/38(2006.01)(52) U.S. Cl.
CPC ............. B63B I/38 (2013.01); B63B 2001/385(2013.01); B63B 2001/387 (2013.01); Y02T
70/122 (2013.01); Y10T 137/3802 (2015.04)

There are provided a main engine 4010 acquiring propelling
powerfor a vessel 1, and a turbocharger 4011 that is driven byexhaust gas from the main engine 4010 and blows pressurizedgas to the main engine 4010. A part of the pressurized gas
and/or exhaust gas is drawn from between the turbocharger
4011 and the main engine 4010 (5023, 5024 and 5025). The
drawn pressurized gas and/or exhaust gas are injected in theproximity 9 of the hull on or below the waterline (5040), andthe drawing rate of the pressurized gas and/or the exhaust gas
is controlled on the basis of a physical quantity related to aheat load on the main engine 10 and characteristics of theturbocharger (4200).
11 Claims, 54 Drawing Sheets

US 9,376,167 B2
Page 2(56)

References CitedJP

H10-24891 A

1, 1998

JP

10100983

4f1998E.

H1is A

3. 2.

10/1989 Naidenov et al. ............. TO1,124
1 1/1990 Jarvi et al.
... 440,66
12/1991 Jarvi et al. ...................... 440,66
4, 1996 Martin ....................... 114,6112
1 1/1996 Kato et al.

JP
JP
JP
JP
JP

11348870
2000-219 188 A
2000296795
2001.048082
2001097 276

12/1999
8, 2000
10, 2000
2, 2001
4/2001

6,145.459 A * 1 1/2000 Takahashi et al. .......... 114/67 A

JP

2002-019689 A

1, 20026,186,085 B1* 2/2001 Kato et al. .....

. . 114f67 A

E.

299;

A

38

6.427.445 B1*
6,789,491 B2 *7,093,553 B2 *8/2002 Isaac et al. .....
... 60,602
9/2004 Takahashi et al. .
114f67 A
8/2006 Robinson et al. ............. 114,288

JP
JP
JP

2004188993
2005-186715 A
2008-013128 A

T 20047/2005
1, 2008

7,162,872 B2 *

1/2007 Schmid et al. .................. 60,602

JP

2008O18128

1, 2008

7,222,704 B2 * 52007
Pearson et al............. 188/378
2002fOO14.192 A1
2, 2002 Takahashi et al.

IP
JP

2008.095466
2008100889

4/20085, 2008

U.S. PATENT DOCUMENTS
4,872,118 A *4,973,275 A *5,074,813 A *5,511,504 A *5,575,232 A

2006.0137345 A1*

6, 2006 Cho ............

... 60.605.1

JP

200810O894

5, 2008

2008/0083361 A1*

4/2008 Iglesias Schoo ............ 114f67 A

JP

2009080676

4/2009WO

FOREIGN PATENT DOCUMENTS
EP
GB
JP
JP

O926.060 A2
2268699. A
S58-78288 U.
S62-137891 U.

6, 1999
1, 1994
5, 1983
8, 1987

W.
WO
WO

87,07233 A1

12/1987

5. A1 1 & 3.
2005122676
2009 122736

12/2005
10/2009

OTHER PUBLICATIONS

E.

: 3.

:E

European Search Report for EP Patent Application No. EP 09 72

JP

6191396

T 1994

7111, Jun. 20, 2013.

JP
JP

O7237589 A * 9, 1995
8243368
9, 1996

JP

HO8-239084 A

9, 1996

JP

HO9-183396 A

7/1997

KIPO, Korean Office Action for Korean Patent Application No.
10-2014-7008398, May 20, 2014.

* cited by examiner

U.S. PatentJun. 28, 2016

Sheet 1 of 54

US 9,376,167 B2s

4s8

U.S. Patent

Fis

Jun. 28, 2016

Sheet 2 of 54

US 9,376,167 B2

U.S. PatentJun. 28, 2016

Sheet 3 of 54

US 9,376,167 B2

U.S. PatentFig. 4

Jun. 28, 2016

Sheet 4 of 54

US 9,376,167 B2

U.S. Patent

Sheet 5 of 54

Jun. 28, 2016

Twauos?laie1§

US 9,376,167 B2

U.S. PatentJun. 28, 2016

91Hi!

Sheet 6 of 54?

US 9,376,167 B2

U.S. PatentJun. 28, 2016

osoaH––swa rvo

1
o
-e
+

01DOE}+-z 01F5E F}+n-1

Sheet 7 of 54

US 9,376,167 B2

U.S. PatentJun. 28, 2016

Sheet 8 of 54

US 9,376,167 B2

Fig. 3

2O4

//

203

SHAPE FFLOW WELOCITYESTRSBITNU.S. PatentJun. 28, 2016

Sheet 9 of 54

US 9,376,167 B2

U.S. PatentJun. 28, 2016

Sheet 10 of 54

US 9,376,167 B2

U.S. PatentJun. 28, 2016

Sheet 11 of 54

Fig.11

SECNA WiiAGNG iiNE X-X

Fig 3

SECTIONAL WEW

ALONG NEX-X

Fig. 3

SECTIONAL WEW
ALONG LINE XaX

US 9,376,167 B2

U.S. PatentJun. 28, 2016

Sheet 12 of 54

Fig.

Fi, isSECTIONAL WEW
ANG NE XaX

US 9,376,167 B2

U.S. PatentJun. 28, 2016

Sheet 13 of 54

Fig. ESECTIONAL WEEWALONG LINE X-X

US 9,376,167 B2

U.S. PatentJun. 28, 2016

Sheet 14 of 54

Fig. 8WATER FOW

US 9,376,167 B2

U.S. PatentJun. 28, 2016

Sheet 15 of 54

US 9,376,167 B2

U.S. PatentJun. 28, 2016

Sheet 16 of 54

US 9,376,167 B2

U.S. PatentJun. 28, 2016

Sheet 17 Of 54

US 9,376,167 B2

U.S. PatentJun. 28, 2016

Sheet 19 Of 54

US 9,376,167 B2

Fig. 23.

TOSPERE

to COOLING WATER

Fig.2

2OO
T COOLNG WATER

EE A

U.S. PatentJun. 28, 2016

Sheet 20 of 54

e

G

6

US 9,376,167 B2

U.S. PatentJun. 28, 2016

Sheet 21 of 54

!”6%

***
##

US 9,376,167 B2

U.S. Patent

US 9,376,167 B2

*
**
~
q~~~~

a

2 a. s.

U.S. PatentJun. 28, 2016

Sheet 23 of 54

US 9,376,167 B2

Fig. 28

FLY LINE

O. C.
WATER FLOW. O.
O. C.

BES
WSHAPEU.S. PatentJun. 28, 2016

Sheet 24 of 54

US 9,376,167 B2

U.S. PatentJun. 28, 2016

Sheet 25 Of 54

US 9,376,167 B2

U.S. PatentJun. 28, 2016

US 9,376,167 B2

Sheet 26 of 54

Ai i Am aas as is a

as a ga as A is a

3 a..., x is

U.S. PatentJun. 28, 2016

Sheet 27 Of 54

US 9,376,167 B2

U.S. PatentJun. 28, 2016

US 9,376,167 B2

Sheet 28 of 54

HMELOYT'MH.

U.S. PatentJun. 28, 2016

Sheet 29 Of 54

US 9,376,167 B2e

U.S. Patent

US 9,376,167 B2

U.S. PatentJun. 28, 2016

*T„•|F-„…--*J+*- -*+
----

|

!
gae

?

Sheet 31 of 54

US 9,376,167 B2

U.S. PatentJun. 28, 2016

Sheet 32 of 54

US 9,376,167 B2

Fig. 37

&

&O

v.

bal
ATMOSPHERE \,-3s-o-c-or-“TJRBIRE is

E

EXHAUST GAs
i
i

-

410 "

3.41 13COMPRESSOR

||
i

f

- -- 4013 CY ENERS
38

s

EXAS
BY-ASSGASU.S. PatentJun. 28, 2016

Sheet 33 of 54

US 9,376,167 B2s
9 Asilioliga japhy-20Bris

U.S. PatentJun. 28, 2016

Sheet 34 of 54

15

US 9,376,167 B2

U.S. PatentJun. 28, 2016

S

s

Y.

r^(e)

BMIEJLIAS

Sheet 36 of 54

US 9,376,167 B2

U.S. PatentJun. 28, 2016

Sheet 37 Of 54

US 9,376,167 B2

Fig. 2

51.18

\

55.
(a) SA CFET(b)\(b) LARE PEG

5151
FLOW

flowance

U.S. PatentJun. 28, 2016

Sheet 38 of 54

US 9,376,167 B2

s

s

e

rts.

% AONgtold dig habir Hoon

U.S. Patent

US 9,376,167 B2

U.S. Patent

is is a sess sex is as as see:US 9,376,167 B2

see s.size: a 2-s: 8 se?

eas a ra as a w is aa s is a us a

is a

|Oz y
s s: gas as as a ste is is als. It is as a is alik i is is as:

U.S. PatentJun. 28, 2016

Sheet 41 of 54

60 £US 9,376,167 B2

U.S. PatentJun. 28, 2016

Sheet 43 of 54

US 9,376,167 B2

Fig. 8

SEE

5095a
RETRACTED conific N.
extra

thirtiU.S. PatentJun. 28, 2016

Sheet 44 of 54

US 9,376,167 B2

W

i
to
is

se

I
I

\

1

3

3

i

i

G

W

s

U.S. PatenteJun. 28, 2016

Sheet 45 of 54

US 9,376,167 B2

y
a

".

f

3.

W

W
s

.

U.S. PatentJun. 28, 2016

Fig. 5E.

y Errorit is starcirc

Sheet 46 of 54

US 9,376,167 B2

U.S. PatentJun. 28, 2016

Sheet 47 of 54

US 9,376,167 B2

U.S. PatentJun. 28, 2016

Sheet 48 of 54

US 9,376,167 B2

Fig. 53

SECTIONAL WE OF HALE

59.5a

U.S. PatentJun. 28, 2016

Sheet 49 of 54

US 9,376,167 B2

as
s

E.

i

-

•

v

f

:

U.S. PatentJun. 28, 2016

Sheet 50 of 54

US 9,376,167 B2

Fig. 55

SECTIONAL LEN F.

5095 --

L.

S5095.

U.S. PatentJun. 28, 2016

Sheet 51 of 54

US 9,376,167 B2

U.S. PatentJun. 28, 2016

Sheet 52 of 54

US 9,376,167 B2

U.S. Patent(a)Jun. 28, 2016

Sheet 53 of 54

US 9,376,167 B2

U.S. PatentJun. 28, 2016

Sheet 54 of 54

US 9,376,167 B2

Fig. 59

E.

s

SO95

595 asUS 9,376,167 B2
1.

2
Further, it is required, as a precondition, that construction
and installation of Such a gas Supply or charged air device
does not cost enormously.
In view of the present states of researches, the inventors ofThis application claims priority to, and is a national phaseapplication under 35 U.S.C. S371 of PCT Application No. 5 the present application use an actual vessel, equip the hull
thereof with a gas inject device capable of injecting bubbles
PCT/JP2009/001520, filed Mar. 31, 2009, which claims thebenefit of Japanese Patent Application No. 2008-095466, with a diameter larger or equal to that of micro bubbles,
filed Apr. 1, 2008, and Japanese Patent Application No. 2008 investigate a relationship between the inject of bubbles and a
100894, filed Apr. 8, 2008 and Japanese Patent Application frictional resistance reduction effect in situations analogous
actualities, such as vessel conditions, navigational condi
No. 2008-100889, filed Apr. 8, 2008 and Japanese Patent 10 totions,
oceanographic conditions, search for increase in net
Application No. 2008-186588, filed Jul. 17, 2008 and Japa reduction
and acquire a lot of findings. Further,nese Patent Application No. 2009-080676, filed Mar. 27, researches effect,
are pursued for optimizing the particle diameters
2009, the entire content of the above applications are of bubbles in order not to diffuse the gas injected from the gas
expressly incorporated herein by reference.
15 inject device in the Sea and separate the gas from the bottomof the vessel, and also on components, devices and the shape
TECHNICAL FIELD
of the bottom of a vessel. Moreover, the researches using suchan actual vessel have determined that the injected bubbles are
The present invention relates to, for example, a frictional convolved into propeller means, reduce the propeller effi
resistance reduction device for a vessel, and more particu ciency and adversely affect a net frictional resistance reduc
larly, to a frictional resistance reduction device for a vessel tion effect.
that injects bubbles into water, controls inject conditions ofOn the other hand, marine diesel engines as the main
engines of large scale vessels are equipped with turbocharg
gas and reduces the frictional resistance of a hull.
ers for compressing and providing air for combusting fuel. In
BACKGROUND ART
25 recent years, the marine diesel engine has realized high powerand high efficiency. This is because, in a large measure, theAs to research on resistance reduction for vessels, a lot of efficiency of the turbocharger has been increased.
Recently, the efficiency of the turbocharger has become
results on wave-making resistance have been acquired. How
higher. There appears a turbocharger exerting efficiency
ever, a distinct result on frictional resistance, which is said tobe responsible for about 80% of the entire resistance of a 30 equal to or higher than that required by the engine. This means
large-scaled vessel, has not been acquired up to the present, that air required for the engine or exhaust gas generated bybecause complicated turbulence phenomena are related combustion of fuel is more than necessary.
Energy-saving techniques that drive exhaust gas power
thereto. When a vessel is sailing, a turbulent boundary layer isdeveloped on or below the waterline along the surface of the turbines using the residual exhaust gas and rotate electric
hull. Accordingly, a frictional resistance is exerted on the 35 generators have generally become widespread (e.g., turbo
surface of the hull, thereby reducing the propulsive perfor compound system). There also arises a concept utilizing themance of the vessel. In recent years, as to means for reducing residual exhaust gas as a source of generating the bubbles.
For example, as shown in following Patent Documents 1 tosuch a frictional resistance on the surface of the hull, a
microbubble system, which reduces the resistance by inject 4, concepts that use the exhaust gas from turbochargers anding microbubbles into the boundary layer along the Surface, 40 generate bubbles have been disclosed.
has received attention as a promising measure for reducing a
Patent Document 1 discloses a technical idea that adjusts
frictional resistance and been researched. It is considered that
fuel adjustment means and gas drawing rate adjustment
the microbubble system is a promising frictional resistance means to reduce fuel consumption while drawing exhaust gas
reduction device in an era from now on when energy saving is from a turbocharger and injecting the gas into water to reduce
desired, because the system is remarkable in frictional resis 45 frictional resistance, and adjusts the flow rate of the exhausttance reduction effect, relatively resistant to fouling, has no gas so as to minimize the amount of fuel Supply as a control.
problem of environmental contamination of the ocean and the However, the idea disclosed in Patent Document 1 only conhydrosphere.
trols the drawing rate so as to reduce the amount of fuel Supply
However, this microbubble system requires power because to a main engine with respect to a prescribed vessel Velocity.
the system generates bubbles with a diameter of a several 50 The optimal control is not necessarily realized. Further, sincehundred um or less from underwater sides of the vessel and only the exhaust gas is used, it is not used in a case of affecting
the bottom of the vessel overcoming the water pressure. Con the environment.
Patent Document 2 discloses a technical idea that provides
siderations are required that increase a net reduction effect inconsideration of both of a frictional resistance reduction
a drawing port at a low pressure spot of a turbocharger com
effect and power for generating bubbles. Further, there is a 55 pressing gas for a main engine and releases the drawn gas into
problem how the frictional resistance is effectively reduced in water. Although the idea disclosed in Patent Document 2
a vessel sailing on the ocean and rivers, which receives vari refers to a valve for adjusting the flow rate, the idea discloses
no specific control method.
ous disturbances, such as waves and streams, and receives
influences owing to freight conditions and navigational con
Patent Document 3 discloses a technical idea that provides
ditions. In particular, buoyancy acting on bubbles is Small on 60 a branch line for a compressed air line of a turbocharger
microbubbles with a diameter of several hundred um or less. provided at a main engine, draws scavenged gas from a spot
When the micro bubbles are injected to the bottom of the downstream from the intercooler and discharges bubbles.
vessel, the microbubble is susceptive to influences of distur However, this idea discloses no specific control methodbances and easily diffused. Moreover, previous researches either, and has a possibility of adversely affecting the opera
have mainly been of a laboratory level and researches using a 65 tion of the main engine.
Patent Document 4 discloses a technical idea of a turbo
model ship, and have not considered the disturbances and thecompound system (exhaust gas passes through the blower
navigational conditions.
FRCTIONAL RESISTANCE REDUCTION
DEVICE FOR SHIP

US 9,376,167 B2
3
turbine and the blower blows the gas to discharge bubbles)that branches exhaust gas out of a main engine, provides aturbine at a branch line, causes the turbine to drive a blower to4hull. However, the idea disclosed in Patent Document 10

provides the regulating member at the sides of the vessel andthe regulating member is fixed Such that a part thereof pro

discharge bubbles from the hull. However, the idea discloses trudes from the bottom of the vessel. Therefore, when theno specific control method, and has a possibility of adversely vessel is carried into a dock because of maintenance of theaffecting the operation of the main engine.
vessel, if the regulating member hits a Supporting stage Such
Patent Document 5 provides the hull with an air injection as blocks, the vessel cannot only be fixed in a stable manner,unit injecting air from a nozzle via an air injection control but also the regulating member becomes an obstacle, thereby
unit, provides a sensor detecting air bubbles or an air sheet reducing working efficiency. Further, the regulating member
released therefrom at the bottom of the hull, inputs signals 10 itself is provided at a side of the hull. Accordingly, the contactfrom the sensor into the hull operation measurement unit, area with seawater becomes significantly large, and the regu
inputs wave information, relative wave information, displace lating member becomes the resistance adversely affecting thement, movement Velocity, acceleration, a direction, detected propulsion of the vessel, thereby reducing the net frictional
conditions of bubbles and a wind velocity and a wind direc resistance reduction effect of the air. Further, since the contion into the hull operation measurement unit, detects bubble 15 figuration where the air is injected from a centerportion in theconditions on the basis of bottom of the vessel pressure infor longitudinal direction of the hull is adopted, the frictional
mation, bubble distribution information, frictional force

resistance reduction effect is limited.

Patent Document 11 discloses a technical idea where, in a
information and hull resistance information, and optimallyvessel having a structure of blowing air into the bottom of thecontrols the released air layer and the bubble conditions.
Since Such a configuration is adopted, various pieces of vessel, the bottom of the vessel has a substantially planardetected information are limited. The control is not per structure with respect to a flow, a lot of grooves are formed onformed by determination of navigational situations, such as the bottom of the vessel so as to be structures for taking air
the relative velocity between the vessel and the water and the into the grooves and air is introduced, thereby separating thedraft conditions, and vessel situations, such as operating con bottom of the vessel and water from each other. However, theditions of the vessel and the engine conditions. This cannot 25 idea disclosed in Patent Document 11 has a structure whereappropriately control the air bubbles and the air sheet. Fur the air is spread at the bottom of the vessel and the bottom ofther, this does not control the number of air injection units the vessel is covered with an air layer. The bottom of theaccording to various pieces of detection information.
vessel is accompanied by the air, but does not have a member
Patent Documents 6 and 7 disclose ideas that control Sup and the like holding the air. An inclination of the vessel owing
ply of pressurized gas and exhaust gas according to pressure 30 to disturbance of the wave, the flow and the like diffuses theand the draft, Supply the gas when the pressure rises to a air toward an area with lower pressure. This reduces thecertain degree and exceeds a pressure determined by a depth amount of air accompanying the bottom of the vessel. It isof water of protruding (injecting) and stop the gas when the inevitable that the frictional resistance reduction effect ispressure decreases. However, these documents do not dis reduced accordingly.
close or suggest an idea that Supplies gas at a higher level. 35 On the other hand, for example, measures as disclosed in
Patent Documents 12, 13 and 14 have been taken in order tostops even at a higher level or blocks after a backflow occurs.
Patent Document 8 discloses a technical idea that pertains reduce the frictional resistance of the vessel using micro
to a micro bubble injecting device, integrally forms a fluid bubbles.
guide plate, which guides bubble-water mixture fluid aft, at
This Patent Document 12 attaches an air injecting device
the front end of a fluid nozzle provided at the hull, and 40 communicated with the blower to a board side of the bow ofconverts a kinetic energy when the bubble-water mixture fluid the hull, attaches an air injecting device communicated with ais injected into propulsion of the vessel. However, the idea compressor to the bottom of the vessel at the bow of the hull,
disclosed in Patent Document 8 is incapable of preliminarily covers areas around the both sides in the board direction of thedetermining the direction of the fluid to be injected. Further, bottom of the vessel and the sides of the vessel with micro
there is a possibility that the fluid guide plate itself becomes a 45 bubbles generated by the air injecting device of the blower,
covers areas around middle section in the board direction ofresistance preventing the vessel from sailing.
Patent Document 9 discloses a technical idea that injects the bottom of the vessel with microbubbles generated by the
bubbles from an air duct, provides strengthening devices air injecting device of the compressor, and entirely covers thestraitening a drift at an upstream and downstream sides of the wet surface of the hull.
air duct, and secures a friction reduction region by spreading 50 Since Such a configuration is adopted, only one air nozzle
the bubbles along the drift. However, according to the idea is provided on each surface of the sides of the vessel or thedisclosed in Patent Document 9, the strengthening device bottom of the vessel. It is incapable of controlling the manner
only plays a role that straitens the drift so as to smoothly flow of blowing bubbles according to the navigational condition of
from the upstream side to the downstream side with respect to the vessel. The reduction in frictional resistance is limited.
the air duct. Therefore, when the velocity of the currents is 55 Further, in a typical blower, the gas Supply or charged air ratehigh, there is a possibility that the bubbles are diffused on varies and the air blowing rate varies according to variation in
injecting. Further, since the air duct protrudes, there is a pressure owing to vertical movement of the waves. This does
possibility that the air duct becomes a resistance preventing not causes stabilized reduction in frictional resistance. Fur
the vessel from sailing. In a case where the vessel is carried, ther, the compressor has a limitation on a rate of air to bewhen the vessel is mounted on a Supporting stage, such as 60 blown by the compressor.
Patent Document 13 provides a plurality of openings at
blocks, the air duct becomes an obstacle in security andworking efficiency.
upper and lower positions with different static pressures ofPatent Document 10 discloses a technical idea that pro outer plates of the hull, attaches air injecting devices to thevides the bottom of the vessel with a regulating member for respective openings, provides a gas drawing type blower
regulating seawater streamed to the side of the bottom of the 65 device including a blower having a low discharge pressure
vessel by inject stream generation means and air injected by and blower having a high discharge pressure on the deck at the
air injecting means So as not to escape toward the sides of the bow, communicates the air injecting device on the upper stage

US 9,376,167 B2
5
6
DISCLOSURE
OF
THE INVENTION
and the blower with the low discharge pressure by the air
Supply pipe, and communicates the air injecting device on thelower stage and the blower with large discharge pressure by
Problems to be Solved by the Invention
the other air Supply pipe.
Since Such a configuration is adopted and, in particular, one 5 As described above, the ideas that use the exhaust gas frommotor drives two blowers, it is incapable of controlling the the main engine directly or indirectly or draw air from themanner of blowing bubbles according to the navigational turbocharger and use this for reducing the resistance of thecondition of the vessel. The reduction infrictional resistancevessel have been disclosed in various manners including theis limited. Further, the nozzles are arranged the upper and 10 above Patent Documents. However, any of these is fraught
lower stages of the vessel. Accordingly, in particular at the with various problems on actual use, or ignores the problems
noZZle on the upper stage, generation of the bubbles is sus to occur in actual use.
For example, gas passing through a turbocharger turbine is
ceptible to vertical movement of the waves. In the blower, thegas Supply or charged air rate varies and gas Supply or charged important gas securing performance and reliability of the
air rate varies according to variation in pressure owing to 15 main engine. The gas rate should appropriately be secured. It
is necessary to control gas Supply or charged air from thevertical movement of waves. Therefore, this idea is not sta
bilized and effective measures for reducing the frictional turbocharger to the main engine or exhaust gas from the main
resistance.
engine, within an appropriate condition, according to the
Patent Document 14 provides a plurality of nozzles in a operating conditions of the main engine. The draw of air fromlimited region in the proximity of the bow in an aggregated the turbocharger and the draw of the exhaust gas after the
fashion in order to reduce frictional resistance between themain engine should be controlled under a strictly controlled
hull and water by injecting gas into water from proximity of condition.
The gas can be drawn around the turbocharger includes
the bow during sailing and thereby causing microbubbles tointervene at the outer shell of the hull. Hydrostatic pressures 'gas Supply or charged air can be drawn after the compressor
generated in the proximity of the nozzles diffuse the bubbles 25 of the turbocharger and before the cooler, “scavenged gas”
can be drawn from between the cooler and the main engine,over the bottom of the vessel.
Since such a configuration is adopted, the bubbles from the and “exhaust gas’ can be drawn from between turbines of theturbocharger after the main engine. The draw of thesenozzles on a curved surface below the valve in the bow section
are susceptive to the navigational conditions of the vessel. 30 changes the air to be supplied to the main engine in pressure,
Since the idea is a passive bubble diffusion system, the flow rate, temperature and the like. This offers a problem
method is incapable of positively controlling generation of whether the main engine is operable under an appropriate
condition and whether the main engine is operable under athe bubble according to the navigational condition of the permissible
condition. The next problem is whether thevessel and thereby effectively reducing the frictional resis drawn gas Supply
or charged air, Scavenged gas and exhausttance. Further, since the nozzles are arranged on an arc toward 35 gas have conditions allowing the frictional resistance of thethe downstream side in the limited region in the bow section, vessel to appropriately be reduced or not. These are different
the resistance at the bow section cannot effectively be in temperature, flow rate, pressure and further position to be
reduced.
drawn. Accordingly, when the plurality of these are combined
Patent Document 1
and used, there arises a problem how to acquire the optimal
Japanese Patent Laid-Open No. 2001-097276
40 value of drawing. Further, in a case of the exhaust gas, an
Patent Document 2
environmental problem that the exhaust gas may directly
Japanese Patent Laid-Open No. 2001-48082
pollute the ocean is assumed, and it is assumed that there are
Patent Document 3
unusable waters. In the waters where the exhaust gas is unus
able, gas Supply or charged air gas or scavenged gas is to be
Japanese Patent Laid-Open No. 11-348870
45 used. Situations can occur that cannot discharge the gas from
Patent Document 4
bypass piping according to draft conditions and operating
Japanese Patent Laid-Open No. 11-348869
situations of the vessel. It is necessary to design so as not toPatent Document 5
damage the engine Owing to immersion of sea water when theJapanese Patent Laid-Open No. 2004-188993
operation is stopped.
Patent Document 6
50
That is, various problems exist, in view of the control,International Publication No. WO2005122676
function, security, and energy-saving design, to realize thePatent Document 7
saving of energy by actually utilizing the bypass gas from theInternational Publication No. WO 1999.028.180
turbocharger and reducing the frictional resistance of the
Patent Document 8
vessel. However, the ideas, including the above Patent Docu
Japanese Patent Laid-Open No. 8-243368
55 ments, only draw and inject the residual gas for the sake ofPatent Document 9
saving of energy or only control So as to minimize fuel con
Japanese Patent Laid-Open No. 2003-160091
Sumption cannot actually solve the above problems and real
Patent Document 10
ize preferable conditions in security and operation. In otherJapanese Patent Laid-Open No. 5-116672
words, the above Patent Documents do not provide specificPatent Document 11

60

Japanese Patent Laid-Open No. 6-191396

Further, as described above, the ideas that use the exhaustgas from the main engine directly or indirectly or draw airfrom the turbocharger and use this for reducing the resistancePatent Document 12

Japanese Patent Laid-Open No. 10-24891

of the vessel have been disclosed in various manners includ

Patent Document 13

Japanese Patent Laid-Open No. 10-100983
Patent Document 14

Japanese Patent Laid-Open No. 2000-296795

measures for resolutions.

65

ing the above Patent Documents. However, any of these isfraught with various problems on actual use, or ignores the
problems to occur in actual use.

US 9,376,167 B2
7
8
For example, gas passing though a turbocharger turbine is tively reduces the frictional resistance even with variation in
important gas securing performance and reliability of the the navigational situations of the vessel and the vessel condi
main engine. The amount of the gas should appropriately be tions, prevents bubbles from being convolved into propeller
secured. The control only minimizing fuel cost is insufficient means, prevents efficiency of propeller means from being
to efficiently maintain the main engine without adversely reduced and increases the net frictional force reduction effect.
affecting the main engine. It is necessary to control air Supply
It is yet another object of the present invention to provide afrom the turbocharger to the main engine and exhaust gas frictional resistance reduction device for a vessel that isfrom the main engine, within an appropriate condition, capable of reflecting navigational conditions and/or vessel
according to the operating conditions of the main engine. The conditions of the vessel in adjustment of gas and injecting ofdraw of air from the turbocharger and the draw of the exhaust 10 gas and thereby realizing saving of energy, prevention ofgas after the main engine should be controlled under a strictly noise, prevention of adverse effects to fishing boats and a port.
controlled condition.
It is still another object of the present application to provide
Further, the techniques that inject bubbles from the hull in a frictional resistance reduction device for a vessel that mainorder to reduce the frictional resistance on sailing of the tains high efficiency without adversely affecting the opera
vessel cannot control the inject conditions such as the direc 15 tion of the main engine when generating bubbles using
tion of the injected gas and the inject rate, according to navi residual gas from a turbocharger, appropriately controls
gational situations of the vessel. Thus, the control for the gas drawing according to situations and realizes security andoutlet cannot be performed, when the vessel receives distur saving of energy.
bances Such as waves and flows, and against an inclination
It is yet another object of the present invention to provide
frictional resistance reduction device and method for a vessel
caused on turning.
Moreover, in the methods guiding the injected gas by that is capable of maintaining high efficiency withoutmeans of external elements, the external elements themselves
adversely affecting the operation of the main engine whencause increase of the frictional resistance and have fixeddrawing the pressurized gas from the proximity of the turbo
structures. Accordingly, in a case of maintenance of the vessel charger and generating bubbles, and thereby preventing theor a case of carrying the vessel into a dock (hereinafter, 25 driving efficiency of the main engine from being reduced.
collectively referred to as “docking situations'), when the
It is still another object of the present invention to provide
vessel is mounted on a Supporting stage such as blocks, the frictional resistance reduction device and method for a vessel
Supporting stage resides under the external elements, thereby that is capable of controlling the inject condition of gas, forconcentrating the stress and causing breakage.
example including the inject rate and the inject direction,
With certainstructures and dimensions of the external ele 30 when injecting gas.
ments, there are problems because operators guide the vessel
It is yet another object of the present invention to provide
over the supporting stage such as the blocks in consideration frictional resistance reduction device and method for a vesselof the external elements under docking situations and the that is capable of suppressing, to a minimum, that a resistanceexternal elements act as obstacles during maintenance of the against sailing of the vessel is formed and/or an obstacle ishull (e.g., including verification of presence or absence of 35 formed under docking situations, and of restricting the diffu
breakage, repairs of the breakage and coating). Moreover,sion of gas even when the vessel receives disturbances such asattachment of the external elements protruding from the bot waves and flows or an inclination occurs owing to turning.
tom of the vessel is concerns in operation of the vessel for
It is still another object of the present invention to provide
officers in charge of operation, in view of security and maneu frictional resistance reduction device and method for a vessel
verability.
40 that is capable of preventing water from entering into a path
The present invention solves the problems of the conven for providing gas and stably Supplying gas from gas Supply ortional techniques. It is an object of the present invention to charged air means.
provide a frictional resistance reduction device for a vesselthat is capable of appropriately controlling a inject of gas
Means for Solving the Problems
according to navigational situations of the vessel and vessel 45
conditions, effectively reducing frictional resistance by
In order to solve the problems, a frictional resistance reduc
appropriately injecting bubbles even with disturbance, and tion device for a vessel corresponding to claim 1 of the present
application includes: a gas outlet injecting bubbles at least to
further utilizing an effect of generation of the bubbles.
It is another object of the present invention to provide a a bottom of the vessel; gas Supply or charged air means forfrictional resistance reduction device for a vessel that retains 50 blowing pressurized gas to the gas outlet; navigational con
bubbles under the navigational situations of the vessel and the dition detection means for detecting a navigational condition
vessel conditions, such as cases of disturbances including of the vessel; and means for controlling injecting of the gas
waves and currents, and a case of an inclination caused by according to a detection result from the navigational condi
turning, and avoids formation of a resistance adversely affect tion detection means such that propulsion of the vessel is not
55 prevented while the injected bubbles efficiently reduces theing advance of the vessel.
It is still another object of the present invention to provide frictional resistance of a hull.
a frictional resistance reduction device for a vessel that is
The 'gas outlet' is a device including a mechanism forcapable of reducing the frictional resistance without necessity injecting pressurized gas Supplied from the gas Supply orof further generating energy for generating bubbles and charged air means as bubbles.
60
reducing consumption of energy according thereto.
Here, the gas Supply or charged air means has a function of
It is yet another object of the present invention to provide a pressurizing and Supplying air, and includes a turbocharger, africtional resistance reduction device for a vessel that realizes
compressor, a blower (gas Supply or charged air device), an
efficient reduction in frictional resistance by injecting electric generation system for driving the blower, and a
bubbles in which the navigational conditions of the vessel is mechanical system directly drives the blower using (high65 pressure) gas.
accurately reflected.
It is still another object of the present invention to provide
The navigational condition detection means may be a relaa frictional resistance reduction device for a vessel that effective velocity detector detecting a relative velocity between

US 9,376,167 B2
9
10
water and the hull, which is a physical quantity varying
The “exhaust gas bypass rate adjustment means' is aaccording to navigation of the vessel, a draft detector detect device including a function of controlling an exhaust gas
ing the height of the waterline of the vessel, an inclination bypass rate according to a control device, which will be
detector detecting an inclination of the hull, and a shear force described later, for example, realized by means of an adjust
5 ment valve and the like connected to the control device.
sensor detecting a shear force acting on the hull.
With these configuration, as to injecting of the pressurized
Further, the exhaust gas from the turbocharger is bypassed
gas from the gas Supply or charged air means via the gas and reused as bubbles, thereby decreasing the resistance onoutlet, the navigational condition detection means detects the the outside of the hull. This facilitates decrease in resistancenavigational condition of the vessel, and then means for con without need for separately generating energy for generating
trolling the injected bubbles such that the frictional resistance 10 bubbles, allowing consumption of the energy thereof to beof the hull is efficiently reduced while not adversely affecting reduced. In this case, the control device is provided that
propulsion of the vessel controls injecting of air on the basis controls the exhaust gas bypass rate on the basis of the physiof the detection result from the navigational condition detec cal quantity related to the heat load of the main engine and thetion means. This can realize reduction in frictional resistance 15 characteristics of the turbocharger. Accordingly, it is secured,of the vessel in the optimal efficiency adapted to variations as a device, that the optimal value of the energy efficiency, insuch as those in the relative velocity between water and the which, for example, variation in the vessel velocity corre
sponding to the load on the main engine is reflected overtime,
hull, the draft of the vessel, the inclination of the hull and theis selected. This allows the effect of reduction in resistance toshear force acting on the hull.
In order to solve the problems, a frictional resistance reduc be reflected over time while appropriately maintaining thetion device for a vessel corresponding to claim 2 of the present condition of exhausting the exhaust gas generated by increase
application includes: a main engine acquiring propelling and decrease of the number of revolutions of the main engine.
power of the vessel; a turbocharger that is driven by exhaust This further realizes a device that maximizes the energy con
gas of the main engine and blowing pressurized gas to the Sumption efficiency, on the basis of calculation and control,
main engine; drawing means for drawing the pressurized gas 25 using vessel resistance reduction effect using bubbles gener
and/or exhaust gas from between the turbocharger and the ated by reusing the exhaust gas from the turbocharger.
main engine; a gas outlet injecting the drawn pressurized gas
In this case, instead ofortogether with the exhaust gas from
and/or exhaust gas at least to a bottom of the vessel on and the turbocharger, gas Supply or charged air and/or scavenged
below a waterline via a path; navigational condition detection gas from the turbocharger is bypassed and reused as bubbles,
means for detecting a navigational condition of the vessel; 30 thereby reducing resistance on the outside of the hull. Thisand a control device controlling a rate of pressurized gas facilitates reduction in resistance without separately generat
and/or exhaust gas on the basis of at least any one of a physical ing energy for generating bubbles, and allows energy con
quantity related to a heat load on the main engine and char sumption to be further reduced. Here, a control device isacteristics of the turbocharger and/or the navigational condi provided that controls a gas Supply or charged air bypass ratetion detection means.
35 and/or a scavenging bypass rate on the basis of a physical
The 'gas Supply or charged air bypass” and the "scaveng quantity related to the heat load on the main engine anding bypass' are compressed a gas in the turbocharger and a characteristics of the turbocharger. The optimal value, inpath for drawing the gas, and concepts including a gas before which, for example, variation in the vessel velocity corre
supply to a cooler (hereinafter, also referred to as “inter sponding to the load on the main engine is reflected overtime,cooler), a gas intermediately cooled by the intercooler, and 40 can be acquired. Use of these gases instead of the exhaust gas
pipes through which the gases pass.
facilitates reduction in resistance without causing a possibil
The 'gas Supply or charged air bypass rate adjustment ity that the exhaust gas causes environmental contamination,means' and the "scavenging bypass rate adjustment means' and effectively facilitates reduction in energy consumption
are devices including functions of controlling a gas Supply or owing thereto, particularly in a case where there is the possicharged air bypass rate and a scavenging bypass gas rate, 45 bility that the exhaust gas causes environmental contamina
respectively, according to a control device, which will be tion.
That is, the control is performed on the basis of the physicaldescribed later, and realized by means of for example, anadjustment valve and the like connected to the control device. quantity related to the heat load of the main engine and the
The “control device' is realized by means of a machine, a characteristics of the turbocharger. This can facilitate thedevice, an instrument, a program, a recording medium on 50 optimization in all aspects, such as output of the main engine,which a program is stored, a computer or the like including fuel consumption efficiency and measures against the exhaust
functions of varying output values and operations (in the gas, of course in reduction infrictional resistance. In this case,present application, for example, various bypass gas rates, in view of a fact that a surplus is generated most under 75%
operation of starting/stopping providing the pressurized gas load on the main engine, further advantageous effect isto the gas outlet, operation of starting/stopping Supplying the 55 expected, in a case of using what has the characteristics of theexhaust gas to the gas outlet, etc.) overtime, based on a certain turbocharger according to which effective use of the Surplus is
number of variables (in the present application, for example, applied to the proximity of 75% load on the main engine anda physical quantity related to the heat load of the main engine, gas can be drawn most at a navigational speed. Any conven
Scavenging gas pressure, exhaust gas temperature, character tional art does not include a concept of drawing from gas
istics of the turbocharger, turbocharger efficiency, pressure of 60 Supply or charged air of the turbocharger, or a concept of
the pressurized gas, pressure of the exhaust gas, the draft of drawing the gas from a high pressure spot between an interthe vessel, etc.), on the basis of a control principles according cooler and a compressor. This concept reduces viscosity ofto the present application.
seawater because of high temperature, even without heating
The “exhaust gas bypass” is the exhaust gas generated as a by the exhaust gas. Accordingly, an advantageous effect isresult of combustion in the engine or a path through which the 65 expected in further reduction in frictional resistance.
exhaust gas is drawn, and a concept including a pipe throughIn the configuration in claim 2, the control device may
control starting/stopping Supplying the pressurized gas and/
which the gas passes.

US 9,376,167 B2
11or the exhaust gas to the gas outlet according to the pressureof the pressurized gas and/or the exhaust gas and the draft of12
Supply or charged air means, thereby securing, as a device,
optimization in energy efficiency. As a result, the advanta
the vessel.
geous effect of reducing the resistance can be reflected overHere, in order to grasp and sense the draft, a method can be time, while appropriately maintaining the condition of
adopted that grasps the waterline from a proportional rela exhausting the exhaust gas generated owing to increase andtionship between pressure and depth using, for example, a decrease in the number of revolutions of the main engine.
sensor measuring and detecting a pressure at the bottom of the This attains reduction in resistance of the vessel using bubbles
vessel or at a surface of a side of the vessel lower than thegenerated by reuse of the exhaust gas of the own device, andwaterline. A method may be adopted that images situations allowing the energy consumption efficiency using the reducaround a water Surface by a camera from a side of the vessel, 10 tion to be optimized, as a device, on the basis of calculation
applies an image processing on the image and thereby esti and control. In other words, it is different, in that control ismates the draft. A pressure sensor may be used for sensing the performed on the basis of the navigational condition detection
pressure of the exhaust gas.
means, the physical quantity related to the heat load of theWith such a configuration, the pressure of the pressurized main engine, and the characteristics of the turbocharger, fromgas and/or the exhaust gas is detected, the operation of start 15 the conventional turbo compound system (i.e., a system ofing/stopping Supplying the pressurized gas and/or the exhaust discharging bubbles from the exhaust gas by means of thegas, which is bypassed from between the turbocharger and the blower via a blower turbine). Therefore, the exhaust gas canmain engine, via the gas outlet is controlled on the basis of the be drawn, while an appropriate value is maintained also in
detected pressure of the exhaust gas and the draft of the view of restriction on exhaust gas. For example, in a casevessel. Accordingly, an event that seawater flows into the where the exhaust gas cannot be discarded directly into thevessel, which occurs when the pressure is equal to or less than seawater and a case where it is necessary to raise the temperathat at the gas discharge port, can be prevented. Further, ture of the exhaust gas and reduces NOx, a preferable control
Supply of the pressurized gas and/or the exhaust gas is started can be performed.
Further, with respect to the above description, a configu
when the pressure condition becomes a condition capable ofinjecting, and stopped when the condition becomes that inca 25 ration may be adopted that further comprises a variable
pable of injecting. This guarantees, as a device, more secure nozzle improving gas Supply or charged air characteristics of
reduction in resistance of the vessel using bubbles. Separately the turbocharger, wherein the variable nozzle is controlled
therefrom, the pressure of the pressurized gas and/or the according to a drawing rate of the pressurized gas and/or theexhaust gas can be shared for managing the conditions of the exhaust gas, the physical quantity related to the heat load on
turbocharger and the main engine, and the draft of the vessel 30 the main engine, and the characteristics of the turbocharger.
The “main engine' of the vessel represents an engine
can be shared for managing the amount of freight.
In this case, basically, when pressure of the pressurized gas driven by liquid fuel orgas fuel, or a gas turbine drive by gas
and/or the exhaust gas is equal to or more than the pressure at fuel.
The “turbocharger Supplying pressurized gas to the main
the draft, injecting of gas is available. When the pressure of
the pressurized gas and/or the exhaust gas is equal to or less 35 engine may, for example, cause the exhaust gas to pass there
than the pressure at the draft, injecting of gas is stopped. In through, rotate an exhaust gas turbine, drive a compressor andactual cases, control is performed on the basis of a value the like, and thereby supply the pressurized gas to the main
therearound including a certain extent of error. This control engine. The exhaust gas rate passing through the exhaust gas
holds effective control, even in cases where conditions vary, turbine of the turbocharger is an important physical quantity
Such as a case where injecting of gas and seawater flow to the 40 for the main engine to secure performance and reliability. It is
opposite directions, thereby allowing a vessel resistance necessary that the value thereof is appropriately be secured.
Further, it is necessary that the gas Supply or charged air rate
reduction effect using bubbles to be strongly attained.
Further, with respect to the above description, a configu from the turbocharger to the main engine is controlled underration may be adopted that further comprises gas Supply or an appropriate condition according to the operating condition
charged air means provided at an exhaust gas bypass drawing 45 of the main engine. Drawing of gas from the turbocharger andthe exhaust gas, wherein the drawing means controls a draw drawing of the exhaust gas after the main engine should be
ing rate of the exhaust gas, and the gas outlet, which is controlled under strictly controlled conditions.
provided via the path from the gas Supply or charged air
The “variable nozzle improving gas Supply or charged air
characteristics of the turbocharger indicates what can adjustmeans, injects bubbles.
Here, the gas Supply or charged air means represents what 50 the direction and angle of Vanes at the nozzle Such that gas
has a function of generating gas, and includes a blower (gas including air and exhaust gas preferably flows into the turbo
Supply or charged air device), an electric generation system charger, when the gas including air and exhaust gas is Sup
for driving the blower, and a mechanical system that directly plied to the turbocharger. More specifically, the variable
drives the blower by means of (high pressure) gas.
nozzle reduces the area of the path and controls the direction
According to Sucha configuration, the exhaust gas from the 55 of flow so as not to reduce the efficiency in driving the turbo
turbocharger is bypassed and used as an exhaust gas bypass. charger. That is, the variable nozzle is arranged at a position
The gas Supply or charged air means is driven by the exhaust capable of controlling the inflow condition of exhaust gas
gas bypass. This generates bubbles to be generated by the gas before the exhaust gas flows into the exhaust gas turbine
Supply or charged air means. The bubbles reduce the resis pertaining to the turbocharger and/or a position capable oftance of the vessel. Here, a control device is provided that 60 controlling the inflow condition of air before air flows fromcontrols the exhaust gas bypass rate on the basis of the physi the atmosphere into the compressor pertaining to the turbo
cal quantity related to the heat load on the main engine and the charger, and cause the inflow air to act on the exhaust gas
characteristics of the turbocharger. The exhaust gas bypass turbine and the compressor even if the inflow gas varies.
The “physical quantity related to the heat load on the main
rate, in which, for example, variation in the vessel Velocity
corresponding to the load on the main engine is reflected over 65 engine' is a physical property value measured or detected intime, is selected. This allows the optimal value to be selected relation to the heat load on the main engine. For example,
each time with respect to generation of bubbles from the gas Scavenging gas pressure, exhaust gas temperature (or tem

US 9,376,167 B2
14
13
perature of an exhaust gas pipe, or ambient temperature that is detector detecting an inclination of the vessel, and a shear
capable of being treated alike or has a relationship therewith force sensor detecting a shear force acting on the hull.
on a one-to-one correspondence), flow rate, the number of
Typically, the control device is electrically controlled. The
revolutions (peripheral speed) of the turbocharger and the control device represents concepts including a program for
like, may be adopted. The efficiency of the turbocharger, and 5 attaining a control object, an algorithm, an electronic medium
property and characteristic values of a degree of matching storing them, and a computer for executing the program andbetween the turbocharger and the engine can be adopted as algorithm, in addition to an electric control circuit. The con
the characteristics of the turbocharger. As acquisition of trol device includes, in addition to electric control systems,
physical quantities, sensors detectable respective physical what is controlled pneumatically or hydraulically, and any
10property values can be adopted.
combination thereof.
With Such a configuration, the degree of open or close and
The control of the gas adjustment means according to theaperture setting of the Vane pertaining to the variable nozzle detectionof the navigational condition detection meansare controlled according to a certain variable. This can opti representsresult
controlof the inverter of the motor, the rotation
mize the inflow condition of the exhaust gas Supplied to theturbocharger. Accordingly, the variable nozzle is controlled 15 adjustment device, the valve and damper for adjusting startaccording to the pressurized gas bypass and/or the exhaust ing/stopping Supplying air and adjusting the air rate, thegas bypass, the drawing rate of pressurized gas and/or exhaust motor and the Solenoids, and the hydraulic and pneumaticgas, the physical quantity related to the heat load of the main drive devices for driving these elements on the basis of theengine, and characteristics of the turbocharger. Accordingly, relative velocity between water and the hull detected by thethe gas Supply or charged air characteristics of the turbo relative velocity detector, the waterline of the vessel detectedcharger are improved. That is, the pressurized gas is prefer by the draft detector, the inclination detected by the inclina
ably Supplied to the main engine, without reducing the turbo tion detector, and the shear force acting on the hull detectedcharger efficiency. The variable nozzle may be controlled so by the shear force sensor. The control varies injecting of air
as to follow the optimal turbocharger efficiency on the basis responsive to the conditions.
of a certain variable pertaining to the characteristics of the 25 With Such a configuration, the navigational condition
turbocharger.
detection means detects the navigational condition of the
The variable nozzle is further provided. Accordingly, adap vessel. The control device performs controls that adjusts thetive adjustment of the variable nozzle can acquire gas to be gas adjustment means to change the number of injecting at the
injected even under low load or high road, thereby allowing plurality of working gas outlets injecting bubbles to the bot
reduction in frictional resistance by injected gas to be real 30 tom of the vessel and/of the inject rate of gas under control ofized.
the control device according to the detection result and effec
In order to solve the problems, africtional resistance reduc tively injects bubbles to the bottom of the vessel according totion device for a vessel corresponding to claim 6 of the present the navigational condition of the vessel. Accordingly, control
application comprises: a vessel; a plurality of gas outlets of the bubble inject condition in which the navigational con
injecting bubbles at least to a bottom of the vessel; gas Supply 35 dition of the vessel is accurately reflected realizes more effi
or charged air means for blowing pressurized gas to the plu cient reduction in frictional resistance.
In the configuration in claim 6, the gas Supply or charged
rality of gas outlets via a path; a drive device driving the gas
Supply or charged air means; gas adjustment means for con air means may plurally be provided, and Supplied to a plural
trolling injecting of gas from the gas outlets; navigational ity of gas outlets via a plurality of paths.
condition detection means for detecting a navigational con 40 With the above configuration, the navigational condition
dition of the vessel; and a control device that controls the gas detection means detects the navigational condition of theadjustment means according to a detection result from the vessel. The control device controls the drive device according
navigational condition detection means and changes a inject to the detection result. The number of working nozzles injectcondition of the pressurized gas from the gas outlets.
ing bubbles to the bottom of the vessel and/or the inject rate ofHere, gas adjustment means represents an inverter or rota 45 gas is changed. The control is performed such that the bubbles
tion adjustment device of a motor for controlling drive of the are effectively injected to the bottom of the vessel according
drive device, a valve or a damper for adjusting starting/stop to the navigational condition of the vessel. In view of allevi
ping Supplying air and adjusting an air rate, and generally, ating adverse effects owing to inclination and waves, it ishydraulic and pneumatic drive devices including a motor and preferable that the gas outlets be plurally provided. This plu
50 ral provision exerts a novel effect capable of controllinga solenoid for driving these elements.
Here, the gas Supply or charged air means represents a injecting so as to inject bubbles only from the middle one or
blower or a turbine-driven compressor securing angas Supply fully inject bubbles according to the relative velocity and theor charged air rate effective for generating bubbles, a pneu draft. Further, this plural provision enables the individual gas
matic source preliminarily mounted on the vessel, or exhaust Supply or charged air means to be minimized, thereby allow
gas that is derived from the engine and pressurized. In par 55 ing the center of gravity of the vessel to be lowered.
ticular, it is preferable that variation in gas Supply or charged
In the configuration in claim 6, the plurality of gas outlets
air rate be Small even if the pressure at a discharge side varies. may be arranged along a fore shape of the bottom of the
The drive device is an eclectically driven motor, an engine vessel.
With Such a configuration, gas can be injected along thedriven by liquid fuel orgas fuel. In addition thereto, the drive
device is a turbine gaining rotational force using the exhaust 60 bottom of the vessel of the hull from the gas outlets arranged
gas from the engine of the vessel, a hydraulic motor or a along the fore shape of the vessel formed in a so-called boat
pneumatic motor driven by hydraulically or pneumatically.
shape. That is, arrangement of the gas outlets along the fore
The navigational condition detection means represents a shape of the bottom of the vessel enables a large area to berelative velocity detector detecting a relative velocity covered with the injected gas. This enables a separate control
between water and the hull, which is a physical quantity 65 Such that air is selectively injected on a spot where resistancevarying according to navigation of the vessel, a draft detector is acting most and selectively facilitates reduction in resis
detecting the height of waterline of the vessel, an inclination tance.

US 9,376,167 B2
15
In the configuration in claim 6, the gas outlets may include
a configuration that does not protrude from a surface of thebottom of the vessel.

The configuration that does not protrude from the surfaceof the bottom of the vessel is, for example, a configuration that
does not protrude from the keel line. The configuration may
be a configuration where a part equipped with the gas outlets

16
trol of injecting bubbles slightly inward, because a slow
Velocity easily causes diffusion) in cases of inclination of thehull and small inject rate of bubbles, thereby allowing thefrictional resistance to be effectively reduced even under ves
sel conditions different from usual conditions.

In order to solve the problems, a frictional resistance reduction device for a vessel corresponding to claim 11 of thepresent application comprises: a vessel; a gas outlet that is
is concave from the surface of the bottom of the vessel, or aconfiguration where the gas outlets are arranged on a Surface provided at a bottom of the vessel and injects bubbles via asubstantially flush with the surface of the bottom of the vessel. 10 path to the bottom of the vessel; gas Supply or charged air
The shape and the dimensions of the configuration are not means blowing compressed gas to the gas outlet; a drive
Subjected to any limitation.
device driving the gas Supply or charged air means; andThis configuration can prevent the gas outlet from being a bubble condition control means that is provided at least after
resistance when the vessel is sailing. Since the gas outlet does the gas outlet and for controlling the injected bubbles.
not protrude, the configuration does not become a load on 15 The bubble condition control means has a function of con
operation under docking situations. More specifically, when trolling the injected bubbles so as to effectively exert thethe vessel is mounted on the Supporting stage such as blocks frictional resistance reduction effect, and includes an end
for fixing the hull, there is no need to consider a protrusion plate, and a bubble convolvement prevention structure.
The end plate is a plate-like material made of materials,
owing to the gas outlet. Since the gas outlets form the sameplane with substantially identical height to the bottom of the Such as metallic material including iron and steel, lumber
vessel, no consideration is necessary. Further, since the gas including cedar and cypress, and FRP. It is preferable that theoutlets can be treated as with another element even in repair of materials be rigid and resistant to rust owing to adverse effectthe bottom of the vessel, the working efficiency is not of moisture and the like. It is further preferable to coat the
impaired.
surface of the materials so as not to cause rust. Methods ofIn the configuration in claim 6, the plurality of gas outlets 25 arranging the end plate include a method of connecting the
may control a inject direction of the pressurized gas and/or a connecting portion material to the bottom of the vessel andinject rate of the pressurized gas.
arranging the material thereon by means of a connecting
The navigational condition of the vessel varies according method including screws, nails and adhesives. However, it isto the relative velocity between water and the hull, the height preferable to adopt methods where the vessel main bodyof waterline of the vessel, the inclination of the hull, the shear 30 pertaining to the bottom of the vessel and the end plate areforce acting on the hull, the depth of water in a navigational fitted to each other by their shapes and/or both are dovetailed
region and the like, which are physical quantities varying together, or connected by welding. In arrangement, thearranging strength may be improved using the connecting
according to navigation of the vessel.
The navigational condition can vary owing to variation in portion material for reinforcement.
any one of prescribed situations of the vessel (total amount of 35 With Such a configuration, the gas Supply or charged air
freight including passengers and cargoes, at the time unnec means driven by the drive device causes the gas outletto inject
essary to injecting gas, at the time of energy saving operation, gas. A plurality of end plates may be arranged, in the asternetc.), a navigational location immediately after departure direction with reference to the gas outlet, around an end
from a port or on cruising, the weather and currents. Accord portion of the bottom of the vessel in the longitudinal direc
ingly, it is necessary to adjust the inject condition of gas in 40 tion thereof. Accordingly, the injected bubbles can flow whilevarious situations along with the navigational conditions. It is being retained at the bottom of the vessel in the water.
necessary to adjust the inject rate and the inject direction of
In a case of adopting the end plate as the bubble condition
gas to acquire a desired frictional resistance reduction effect. control means, according to this configuration, the end plate
The inject rate of gas can be adjusted by means of the drive is arranged after the gas outlet of the bottom of the vessel.
control by the gas Supply or charged air means, generation 45 Accordingly, Small amount of the contact area with water israte of gas and the like. Further, the inject rate of gas can also Sufficient in comparison with the case of arranging the end
be adjusted by means of changing the aperture of the nozzle plate on the side of the vessel (e.g., comparison with the above
immediately before injecting. On the other hand, the inject Patent Document 11), and increase in frictional resistancedirection of gas can be adjusted by means of providing a owing to the end plate is significantly small. Further, it isstraightening plate on the nozzle to adjust the angles, chang 50 advantageous to provide the end plate on the bottom of theing the directions of a nozzle configuration itself of the vessel, in view of stability of the vessel. More specifically,
accumulation of air on the vessel side disturbs the balance,
noZZle, and utilizing a fluid element.
Such a configuration is effective, in a case incapable of which further means that the bubbles have generated in vain.
acquiring a desired frictional resistance reduction effect This configuration with arrangement on the bottom of theowing to the navigational condition of the vessel, even if the 55 vessel can avoid such an event.
gas Supply or charged air means for generating gas appropri
In a case of adopting a bubble convolvement prevention
ately controls the Supply rate. For example, there is a tendency structure as the bubble condition control means, the bubble
that the bubbles are diffused by buoyancy responsive to the convolvement prevention structure can prevent the bubbles
navigational conditions varying according to influences due from being convolved into the propeller means and the liketo the relative velocity between water and the hull, the height 60 and becoming obstruction of maneuvering, without receiving
any effect owing to waves or currents.
of waterline of the vessel, the inclination of the hull, the shear
force acting on the hull, the depth of water in a navigational
The configuration in claim 11 may further include retract
region and the like. In these cases, if the inject direction of gas able diffusion limiting means for limiting bubble diffusion,
can preliminarily be adjusted, the loss of the frictional resis which is provided as the bubble condition control means.
tance reduction effect can be prevented. The above configu 65 Here, the diffusion limiting means, for example, Supration realizes that. Further, this allows a control of effectively presses bubble diffusion around the bottom of the vessel
spreading bubbles around the bottom of the vessel (e.g., con caused by normal sailing (including sailing in a straight line

US 9,376,167 B2
17
and turning) and a sudden inclination of the vessel owing towaves and wind force. The diffusion limiting means may be
the end plate, a rib structure (e.g., a rib structure with atriangular profile), a mound structure, a fin structure and the18
the diffusion limiting means or the elastic force of the elastic
member. On the contrary, the state of retracting the diffusion
limiting means is maintained during receiving the compress
ing load. In particular, in order to bend the diffusion limiting
like.
means, it is preferable that a prescribed inclination be pro
More specifically, the diffusion limiting means is made of vided for easily bending the diffusion limiting means and thematerials, such as metallic material including iron and steel, compressing load be received without contacting with theand FRP and the like, and may be a plate-like or streamlined diffusion limiting means or the like. A configuration may be
structure where the whole or a part thereof protruding from adopted where variable movement by a drive mechanism or athe hull. It is preferable that the materials be rigid and resistant 10 link mechanism and movement by the self weight of theto rust owing to adverse effect of moisture and the like. It is diffusion limiting means or the elastic member attached to thefurther preferable to coat the surface of the materials so as not diffusion limiting means are combined and thereby realizes
to cause rust. The shape and the dimensions of the diffusion protrusion and retraction. More specifically, the self weight
limiting means are not subjected to any limitation.
may be used when the diffusion limiting means protrudes,
Accordingly, "retractable diffusion limiting means' repre 15 and retraction may be performed by the drive mechanism or
sents what is capable of causing the diffusion limiting means the like at an arbitrary timing.
With Such a configuration, the diffusion limiting means canto be a state of protruding from the main body of the vessel,
such as the bottom of the vessel or a bow section, or a state of limit diffusion of the gas blown from the gas Supply or
retracting.
charged air means and injected from the gas outlet during
Here, the state of protruding the diffusion limiting means sailing, and the gas can flow while being maintained in the
represents a state where diffusion limiting means can prevent proximity of the bottom of the vessel. With the retractablebubble diffusion around the bottom of the vessel caused by a configuration, when the vessel entering a port or sailing in
Sudden inclination of the hull owing to influences, such as shallow water, if reduction in frictional resistance by bubbles
rolling by normal sailing (including sailing in a straight line is unnecessary, the diffusion limiting means is retracted.
and turning) with the diffusion limiting means, waves, wind 25 Accordingly, the diffusion limiting means does not act as aforce and the like, and a state where diffusion limiting means resistance or an obstruction, and does not become a load on
can exert an effect on a prescribed operation under docking operation under docking situations. That is, in comparison
situations, and also includes a state where a part of the end with the case where the end plate is not retractable as in theplate (a distal end, etc.) protrudes.
above Patent Document 16, retraction can be performed whenOn the other hand, a state of retracting the diffusion limit 30 the vessel is sailing and the diffusion limiting means is unnec
ing means represents, for example, a state where a Surplus essary, thereby reducing the frictional resistance. Further,
space arranged in the main body of the vessel, such as the when stability of the vessel is required, protrusion thereofbottom of the vessel or the bow section stores the entire parts also serves as stabilization means (i.e., in addition to resisof the diffusion limiting means and no part protrude or a part tance, an effect of lowering the center of gravity is exerted).
of the diffusion limiting means is retracted and the other part 35 Moreover, when bubbles are injected, the diffusion limiting
protrudes, or a state where the diffusion limiting means is effect is acquired together with the stabilization effect.
folded at a boundary plane between the diffusion limiting
The configuration in claim 11 may further include diffumeans and the main body of the vessel. The above limiting sion limiting means that is transformable according to anmeans can also function as the diffusion limiting means. The internal/external force limiting bubble diffusion and provided
retraction is performed when air is not injected, when the ship 40 as the bubble condition control means.
is carried into a dock, and when cooperation with injecting ofHere, as in the above the “diffusion limiting means’ cangas is performed as control.
prevent bubble diffusion around the bottom of the vessel
The configuration realizing the protrusion and the retrac caused by a Sudden inclination of the vessel owing to influ
tion of the diffusion limiting means includes means for ences by normal sailing (including sailing in a straight line
reversibly driving the diffusion limiting means by a drive 45 and turning), waves and wind force, and configured with amechanism. The drive mechanism is a power source, such as flexible material.
a hydraulic, water-pressurized or pneumatic actuator, or aMore specifically, the diffusion limiting means may be, formotor, capable of linking to the diffusion limiting means, and example, a hollow object (hereinafter, also referred to aspreferably arranged in the Surplus space provided in the main “hollow structure') made of material having a certain extent
body of the vessel, such as the bottom of the vessel or the bow 50 of elasticity, rigidity, flexibility or resiliency and/or strength
section. In this case, the drive mechanism is capable of driv including vinyl, rubber or various textile (e.g., materials used
ing the diffusion limiting means so as to protrude and be for a flak jacket and the bottom of the vessel of an air-cushion
retracted. The drive mechanism may be operated manually or vehicle), or an object in which a flexible material such as
automatically on sailing according to control on the basis of a sponge is filled. In this case, the shape (e.g., a round, an oval,
55 a triangle, a rectangle, another polygon, etc.) is not subjected
predetermined condition.
The drive mechanism may be a link mechanism configured to any limitation. However, the shape is preferably adopted toby combination with a joint and the like. This allows the linear which an internal force is applied by filling or encapsulating
movement of the drive mechanism to be converted into rota
fluid (gas Such as air, or liquid Such as water or oil) or finetional movement by means of the link mechanism and the particles such as powder or dirt therein, thereby allowing a
like.
60 desired shape to be maintained even in Sailing. In particular,
On the other hand, the diffusion limiting means can pro with flexibility, under docking situations, when the vessel istrude by the self weight according to receiving gravity and/or mounted on the Supporting stage Such as blocks, it is preferby urging by an elastic member such as a spring attached able that the diffusion limiting means be capable of being
thereto, and be retracted by receiving compressing load from compressed (crushed) by an external force owing to the presunderneath. In other words, the state where the diffusion 65 sure. Further, the injected or encapsulated fluid of fine parlimiting means protrudes is maintained unless receiving com ticles may be drawn or taken out. The inside and the outsidepressing load from underneath greater than the self weight of of the object may be configured only with an elastic material,US 9,376,167 B2
19which may be anything capable of maintaining an expanded
state without being compressed owing to the water pressure
when the vessel is sailing, preventing bubbles from being
diffused when the vessel is sailing and maintaining the20
The bubbles generated by the injected gas receive an influ
ence owing to buoyancy by a starboard and port inclinationsof the hull. Accordingly, diffusion can be suppressed byblocking the moving direction of bubbles by the diffusion
bubbles to be retained at the bottom of the vessel and flow. 5 limiting means. On the other hand, as described above, theAccordingly, the “transformable diffusion limiting means’ diffusion limiting means may be a solid plate-like object oran
includes that the diffusion limiting means is capable of being object expanded using elastic material. Without limitation
in a state of protruding from the bottom of the vessel or a state thereto, the object may be a pseudo wall formed by injectingof being contacted, and represents what is transformable into liquid at a prescribed flow velocity. More specifically, the10various shapes and States desired.
limiting flow generation means capable of generating theHere, the state where the diffusion limiting means pro pseudo wall by the flow of liquid is arranged in the hull in thetrudes represents that fluid Such as air or water, fine particles proximity of the bottom of the vessel, thereby allowing thisor the like is injected or encapsulated into the hollow diffusion technical idea to be realized.
limiting means to apply an internal force, thereby maintaining
a desired shape without being compressed by the water pres 15 With Such a configuration, the limiting flow generation
sure even when the vessel is sailing. Further, the diffusion means generates the flow of liquid having a prescribed extent
limiting means may be anything that is not hollow, and like and a thickness dimension. This forms a so-called pseudo
wise includes anything capable of maintaining a desired wall (end plate), blocks the bubble diffusion path, and Sup
shape without being compressed by the water pressure even presses the bubble diffusion generated by the inclination of
the vessel, thereby allowing the bubbles to flow while being
when the vessel is sailing.
On the other hand, the state of contracting the diffusion retained in the proximity of the hull. Further, the limiting flow
limiting means represents a state where there is no or Sub generation means is arranged in the bottom of the vessel So as
stantially no internal force pertaining to the diffusion limiting not to protrude. This prevents the limiting flow generationmeans, or a state of maintaining a state of contracting where means itself from becoming a resistance, and negates the needthe diffusion limiting means is crushed during receiving the 25 for considering the positions of blocks in consideration of thecompressing load greater than the internal force despite of limiting flow generation means under docking situations,presence or absence of the internal force. Further, the con thereby negating the operational obstruction.
For example, a pump is used in order to generate such a
traction is performed when gas is not injected, when thevessel is carried into a dock and when cooperation with inject limiting flow. It is preferable that the direction of the limiting
30 flow be, for example, a direction Substantially orthogonal toing of gas is performed as control.
With Such a configuration, the diffusion limiting means is the bottom of the vessel. For example, if the flow rate of the
expanded by applying a prescribed internal force. This can limiting flow is proportional to the inject rate of bubbles,
prevent bubbles from being diffused around the bottom of the limiting flow is generated more efficiently. Further, forvessel caused by a Sudden inclination of the hull owing to example, when the vessel is inclined, a control may be per
influences of rolling by normal sailing (including sailing in a 35 formed Such that the limiting flow is generated more at ashallow area. Together therewith/alternatively thereto, thestraight line and turning), waves, wind force and the like.
Further, the diffusion limiting means is contracted without flow rate of the limiting flow may be controlled according toapplication of the internal force thereto, or contracted during the vessel velocity. This can effectively prevent the bubbles
receiving a load greater than the internal force, because the from being diffused, and prevent the limiting flow generation
diffusion limiting means is crushed. Accordingly, in a state of 40 means itself from being a resistance.
contraction, when gas is not injected, the diffusion limiting
The configuration in claim 11 may further include a conmeans does not become a resistance. Further, under docking volvement prevention structure that prevents bubbles fromsituations, the diffusion limiting means is crushed by receiv being convolved into the propelling device of the vessel and is
ing the compressing load from the Supporting stage Such as provided on a stern side after the gas outlet at least on theblocks. Accordingly, the diffusion limiting means does not 45 bottom of the vessel as the bubble condition control means.
The convolvement prevention structure represents strucbecome an obstacle, the vessel can be fixed, and no influenceexerted on operation such as a repair of the bottom of the tural measures for preventing bubbles from being convolved
vessel.
into the propeller means, indicates all structures effectively
On the other words, in comparison with the case of the end preventing bubbles from being convolved into the propeller
plate not retractable as in the above Patent Document 16, and 50 means, such as a protuberance having an after-mentioned
with the end plate that is not transformable according to the curved Surface, including a V-shaped mound, a fin structure,internal/external force, in this configuration, retraction by a bubble protection and a porous, and preferably is a structure
reducing the internal force when it is unnecessary in sailing where increase in resistance is Small as the vessel is propelled.
With the above configuration, the convolvement preven
reduces the frictional resistance, while also serving as stabi
lization means by increasing the internal force and protruding 55 tion structure arranged at least on the bottom of the vessel
when stability of the vessel is required. When the bubbles are after the gas outlet causes the bubbles blown by the gas supply
injected, the effects of diffusion limitation and of the stabili or charged air means and injected from the gas outlet to
Zation means can be acquired at the same time. Further, trans escape so as not to be convolved into the propeller means.
formation is automatic according to pressure. A deep water More specifically, the bubble convolvement prevention strucline causes contraction (Small amount of bubbles), and an 60 ture can prevent the bubbles from being convolved into theinclination causes expansion at the risen side, thereby pre propeller means and the like and becoming an obstruction
venting air from escaping.
against maneuvering, without receiving influences owing to
The configuration in claim 11 may further includes limit waves and currents. In particular, according to the mound anding flow generation means for generating a flow limiting fin structures, the shape can prevent convolvement. Accord
diffusion of bubbles injected from the gas outlet. The limiting 65 ingly, an event that the function is impaired owing to a failure
flow generation means is provided as the bubble condition and the like is not required to be considered. The prevention
control means.
of bubble convolvement can always be realized.

US 9,376,167 B2
21
The configuration in claim 11 may further include bubble
drawing means for drawing at least bubbles provided after thegas outlet and before a propelling device of the vessel, as the22means for detecting a navigational condition of the vessel
and/or the vessel conditions determination means and per
forms control of starting/stopping injecting gas from the gas

bubble condition control means, wherein the drawn bubbles

outlet.

are discharged to the outside.
Here, the bubble drawing means represents what is oper
ated using a dedicated power. Such as a blower drawing the
bubbles, a compressor, a pump drawing water in whichbubbles are mixed, and an ejector and what uses existing

Here, the vessel conditions determination means generally
represents means, apparatuses and equipment for determin
ing situations where the vessel resides in a broad sense. Suchas operating conditions of the engine of the vessel, the spe
cific fuel consumption of the engine, a GPS (Global Position
facilities of the vessel.
10
System) detecting which waters and location the vesselWith the above configuration, the bubbles injected from the ing
resides
in, a gyro, a radar, an amount of freight measurement.
gas outlet are drawn by the bubble drawing means arranged The navigationalof the vessel represents physicalbefore the propeller means such that the bubbles are not quantities varyingcondition
accordingto navigation of the vessel (theconvolved into the propeller means. The drawn bubbles aredischarged to the outside where there is no influence owing to 15 relative velocity between water and the hull, height of water
the propeller means. According to this, although, in a case of line of the vessel, inclination of the hull, shear force acting on
the configuration that recirculates the drawn bubbles as dis the hull, depth of water in the navigational region, etc.) owing
closed in National Publication of International Patent Appli to influences of waves, currents, wind directions, wind force,
the waterline of the vessel and the like. The vessel conditions
cation No. 2001-524.421, recirculation causes decrease intemperature and reduction in Viscosity is not expected, this represent conditions grasped by means of determining theconfiguration discharges the bubbles to the outside and conditions where the vessel resides, such as engine operating
thereby does not decrease the temperature and reduction in conditions, specific fuel consumption, a GPS, a gyro, a radar,
Viscosity can be expected, in contrast to that.
an amount of freight measurement.
The configuration in claim 11 may further include bubble
In the above case, starting/stopping conditions may include
convolvement detection means for detecting convolvement of 25 cases where waves become weaker/stronger, currents become
bubbles into a propelling device of the vessel, as the bubble weaker/stronger, winds become weaker/wilder, the relative
condition control means, whereina inject condition of the gas velocity become higher/lower, the waterline becomes lower/
outlet and/or an operating condition of the propelling device higher, the shear force becomes stronger/weaker, the depth ofis changed when the bubble convolvement detection means water becomes deeper/shallower, the engine starting upfin
detects convolvement of bubbles.
30
stop operation, the specific fuel consumption becomes worse/
Here, the bubble convolvement detection means generally better, leaving/approaching a port, and another vessel leavrepresents a sensor that detects variation in driving force of ing/approaching.
the propeller owing to convolvement of bubbles into the pro
Conditions for controlling the amount of bubbles maypeller means as variation in thrust force or torque of the include
that increases/decreases the amount accord
propeller drive shaft, a vibration sensor that detects vibration 35 ing to thecontrol
relative
velocity becomes higher/lower, the water
generated at the propeller means by convolvement of bubbles,
an acoustic sensor that detects Sounds generated by convolve line becomes lower/higher, the shear force becomes stronger/
ment of the bubbles and variation thereof, and imaging means weaker, and the depth of water becomes deeper/shallower.
Methods (and advantageous effects) of starting/stoppingthat detects convolvement of the bubbles as images by a video
camera and the like.
40 include preliminarily operating the gas Supply or charged air
With the above configuration, when the bubbles injected means and then opening the valve? preliminarily closing thefrom the gas outlet are convolved into the propeller means, the valve and then stopping the gas Supply or charged air means
inject condition of the gas outlet and/or the operating condi (preventing seawater from coming in the air Supply pipe),tion of the gas Supply or charged air means are changed, opening/closing at a prescribed relative Velocity (injecting
thereby reducing the convolvement of the bubbles into the 45 gas at a relative velocity having frictional reduction effect),and stopping when entering a port/opening when leaving thepropeller means.
Previously, there is no idea that detects convolvement of port (preventing eutrophication).
With Such a configuration, the navigational condition
bubbles and performs control based thereon. However, thisconfiguration is also capable of detecting occurrence of cavi detection means detects the navigational condition of thetations and thereby effectively taking measures. In this case, 50 vessel and/or the vessel conditions determination meansa detector detecting variation in thrust force or torque, a determines the situations where the vessel resides and thedetector detecting vibration, a detector detecting generated device adjusts the gas adjustment means on the basis of theSounds, imaging means, a ultrasonic sensor, a pneumatic detection result and/or the determination result, injects gas
sensor and the like, can be adopted as the bubble convolve from the gas outlet and stop the injecting, thereby effectively
ment detection means. Further, control on the propeller side, 55 controlling injecting of bubbles according to the navigationaland control on injecting of gas (control on the rate, the direc conditions and the vessel conditions. With respect to thistion, and the number of working nozzles), and a combination point, previously, there is no concept that adjusts the gas
adjustment means according to the navigational conditions ofof both and the like, can be adopted as control method.
In order to solve the problems, a frictional resistance reduc the vessel and/or the vessel conditions and performs control
tion device for a vessel corresponding to claim 18 of the 60 that starts/stops injecting of gas. With the adjustment of thepresent application includes: a vessel; a plurality of gas out gas adjustment means according to the navigational condi
lets injecting bubbles at least to the bottom of the vessel; gas tions of the vessel and/or the vessel conditions in the configu
Supply or charged air means for blowing pressurized gas to ration, injecting of air is started/stopped responsive to thethe plurality of gas outlets via a path; gas control means for navigational conditions of the vessel. Such as waves, currents,
controlling injecting of the pressurized gas from the gas out 65 the wind direction, wind force, the draft of the vessel, and thelets; and a control device that adjusts the gas control means vessel conditions, such as engine operating conditions andaccording to a condition of navigational condition detection specific fuel consumption. This exerts advantageous effects,

US 9,376,167 B2
24
23
Such as prevention of noise and prevention of adverse influ means may be an inclination detector detecting an inclination
ences to fishing boats and ports, in addition to an energy of the hull, adopt a configuration where the number of work
consumption effect.
ing gas outlets laterally arranged on the vessel and/or the
In the configuration corresponding to the embodiments of inject rate of gas is controlled according to the inclination.
the present invention, when the navigational condition detec 5 The inclination detector can be used for another application means and/or the vessel conditions determination meanstion for the vessel (e.g., the air inject rate of air is decreased or
detects/determines that the vessel is stopped, the gas Supply stopped when freight conditions are verified and when varia
or charged air means may be stopped.
tion in inclination is large, etc.).
With Such a configuration, the gas adjustment device is
Methods (effects thereof) of stopping the gas Supply or
charged air means may include stopping after stopping the 10 controlled according to the degree of inclination of the hull
valve (preventing seawater from coming in), stopping before detected by the inclination detector. Because the number ofstopping the engine (stopping before power-down of the elec gas outlets and/or the inject rate of gas is appropriately
tric generator and stopping the turbocharger), stopping simul adjusted when turning and rolling, the bubble diffusion con
taneously with the stop of the engine (operating together with ditions are appropriately controlled by decreasing the number
the turbocharger), stopping after unloading of the freight 15 of working nozzles where gas is injected at a shallow side of(adjustment of the draft).
the inclination and increasing the number of working nozzles
With such a configuration, when it is detected/determined where gas is injected at a deep side of the inclination when thethat the vessel is stopped, the control device stops the gas vessel is inclined, thereby allowing effectiveness infrictional
Supply or charged air means to stop the injecting of gas from resistance reduction to be improved.
the gas outlet. In a case of using the turbocharger, injecting ofIn the configurations corresponding to the embodiments ofgas may be stopped in a linked manner to the stop of the the present invention, the navigational condition detection
turbocharger accompanying a stop of the engine. Further, the means may adopt a configuration of being attached to a spot
injecting is stopped by determining a stop of the vessel. This at least without receiving influences of the bubbles.
can prevent navigational condition detection means from per
The navigational condition detection means includes what
forming erroneous detection owing to residence of bubbles at 25 is arranged at a prescribed part of the hull facing water, Suchthe hull accompanying a stop of the vessel (measurement of as a depth Sounder measuring a depth of water at a naviga
tional region. A principal object of the present application isthe depth of water when entering a port, etc.).
In configurations corresponding to the embodiments of the to reduce the frictional resistance by causing bubbles injected
present invention, the navigational condition detection means from the gas outlet to flow around the bottom of the vessel
may be a relative velocity detector detecting a relative veloc 30 while retaining the bubbles therearound. The inject condition
ity between the hull and the water, and adopt a configuration of gas is controlled on the basis of the various types of detec
where the number of gas outlets and/or the inject rate of gas tion results from the navigational condition detection means.
are increased or decreased according to increase or decrease Accordingly, optimization of the detection conditionof the relative velocity.
improves the reliability of the detection result, forms a
The systems of the relative velocity detectors (sensors) 35 desired inject condition and thereby improves the reduction in
may include an ultrasonic system, an electromagnetic system, frictional resistance.
With Such a construction, the position where the naviga
and a laser system. When the relative velocity detector is usedtional condition detection means facing water is arranged at a
for an air-lubricated method, a lot of bubbles intervene at theSurface of the sea, thereby allowing measurement to be more position without receiving influences of the injected gas.
accurate because of diffused reflection in cases of the laser 40 More specifically, the position is a spot where the naviga
system and the ultrasonic relative Velocity sensor.
tional condition detection means is not covered with gas
With such a configuration, the number of nozzles and/or during detection, gas does not come into a detection region
the inject rate of gas are controlled according to increase and and a stable detection condition can be maintained. Thisdecrease of the relative velocity between the hull and a water allows a desired detection result to be reliably acquired.
system, such as seawater or river water, instead of an absolute 45 Because attachment of the navigational condition detection
ground velocity of the vessel. Because the control is per means does not receive influences owing to bubbles, foulingformed according to detection of the relative velocity, the of marine organisms is a little, which can prevent unexpected
control becomes more accurate than that using a displace failures, malfunctions, accidents and the like owing to thefouling from occurring. Systems of the navigational condi
ment, kinetic, acceleration sensors. Further, the relative
Velocity sensor can be shared for another use such as mea 50 tion detection means include a relative Velocity detector, aSurement of currents.
draft detector and an inclination detector. When any one of
In the configurations corresponding to the embodiments of these is used, attachment on the position without receiving
the present invention, the navigational condition detection influences of bubbles can be performed.
In the configurations corresponding to the embodiments ofmeans may be a draft detector detecting the draft of the vessel,
and adopt a configuration where the number of gas outlets 55 the present invention, a configuration may be adopted that the
and/or the inject rate of gas are increased or decreased accord path is raised on or above the waterline and then connected to
ing to the height of the waterline.
the gas outlet.
With this configuration, the piping passes at a height equal
The draft of the vessel can be shared for used for managing
the amount of freight. In principle, it is controlled such that to or above the waterline. This can prevent seawater frominjecting of gas is available when the pressure of the pressur 60 coming into the gas outlet arranged on or below the waterline,
ized gas and/or the exhaust gas is equal to or more than that at thereby allowing security of the main engine to be further
the draft, and injecting of gas is stopped when the pressure of increased.
the pressurized gas and/or the exhaust gas is equal to or lessThat is, a heavy main engine (in a case of using a turbo
than that at the draft. Because this control appropriately charger) and the gas Supply or charged air means can be
65 arranged on or below the waterline while backflow of water is
injects gas, the seawater does not cause backflow.
In the configurations corresponding to the embodiments of prevented, thereby improving stability of the vessel. In thisthe present invention, the navigational condition detection case, the backflow of water can be prevented in a threefold

US 9,376,167 B2
25
26
ing
to
the
navigational
conditionin comparison with a case ofmanner by a structure where the path is raised once at thewaterline or higher and then connected to the gas outlet, a constantly injecting gas. A further frictional resistance reduc
structure with open and close means arranged before the gas tion effect can thus be expected.
Further, according to the present invention, the gas Supply
outlet, and a structure of cooperation with a valve arranged
after the turbocharger and the gas Supply or charged air 5 or charged air from the gas outlets symmetrically arranged
CaS.
with respect to the planar center line of the hull is symmetri
In the configurations corresponding to the embodiments of cally controlled according to the detection result from thethe present invention, a configuration may be adopted that the navigational condition detection means. Accordingly, in parpath is blocked at the proximity of the gas outlet when inject ticular, when the vessel is sailing in a straight line, a uniform
ing of the pressurized gas and/or the exhaust gas is stopped. 10 frictional resistance reduction effect can be expected. This
Blocking of the path includes, for example, a manner can prevent the ability to hold a straight line from being
where an open/close valve, which passes and blocks the air impaired owing to the injecting of bubbles. Further, control is
Supply pipe connected to the gas Supply or charged air means symmetrically performed on the laterally arranged gas out
and the gas outlet, opens always at least during gas Supply or lets. Accordingly, the control can be performed by means ofcharged air and closes when gas Supply or charged air is circuits with the laterally same configurations, the same cir
stopped. The operation of opening and closing can be realized cuit, or output from the same port. This allows the control to
by a gate value that open and closes the fluid path by operation be simplified and can facilitate rationalization of the circuits.
Further, according to the present invention, the gas Supply
of a disc-shaped valve body stored in a valve box of the valve
in a right angle with respect to the fluid path, a stop valve or charged air means is arranged on the top of the hull and thecapable of adjusting the flow rate by closing the valve body gas from the gas Supply or charged air means is guided into
stopping the flow of the fluid, a check valve that unidirection the bottom of the vessel via the air supply pipe. This canally maintains the fluid and prevents backflow or the like. The reduce variation in inject rate of bubbles along with variation
open/close can be performed manually or automatically in pressure owing to influences of waves in a case of use in theaccording to control on the basis of a predetermined condition ocean, by a buffer effect due to the volume of the air supply
25 pipe. This indicates that, because the air Supply pipe has aon sailing.
According to this configuration, provision of the configu considerable volume from the top of the hull to the bottom ofration blocking the path allows the path to be blocked when the vessel, the gas intervening in this Volume space is allevi
gas Supply or charged airis stopped, orgas does not pass. This ated by a resiliency effect when being compressed andcan prevent backflow of water in the air supply pipe. Further, decompressed, and variation in pressure in the gas outlets
without contact with water, corrosion in the air Supply pipe, 30 owing to variational height of the waves are reduced. Further,and fouling owing to adhesion and reproduction of algae and bend of the path at the bottom of the vessel at the right angle
shellfish, such as barnacles and oysters, can be prevented. causes an effect that the gas changes the direction and two
Moreover, since the opening is closed when bubbles are not dimensionally spreads. However, the gas is guided into thegas outlet. This can solve the problem of impairing the dis
injected, increase in frictional resistance can be suppressed.
In this case, a method can be considered for the control of 35 tribution of Velocity of flow of gas at the gas outlet, particu
blocking the path. This method blocks the path in the prox larly in the direction parallel to the bottom of the vessel.
Further, according to the present invention, a plurality ofimity of the gas outlet, first. Next, the bypass valve is closed
and Subsequently the turbocharger is stopped. A pressure is perforated plates having pluralities of apertures are arranged
thus reserved in the piping path. Accordingly, intrusion of in series such that the positions of apertures are displaced, and40 configures the gas outlet. Accordingly, the plurality of perfo
water can further be prevented.
rated plates cause the flow of gas to be bent, and can exert aAdvantages of the Invention
so-called baffle plate effect. This baffle plate causes an effectthat the plurality of displaced perforated plates provide resis
According to the present invention, bubbles are injected tance, and is capable of injecting gas from the gas outlet in afrom the plurality of gas outlets arranged at the bottom of the 45 uniform state. Further, this allows the plurality of perforated
vessel, by controlling the plural pieces of gas Supply or plates having the same aperture pitch to be utilized, andcharged air means provided corresponding to the respective manufacturing economies of scale can be expected in view ofgas outlets, according to the navigational condition. There in view of industry, thereby enabling a product to be provided
fore, rise of bubbles can be inhibited by the bottom of the at low cost.
vessel itself, the bubble retention effect can be maintained, 50 Moreover, according to the present invention, the gas Sup
and the frictional resistance can effectively be reduced by a ply or charged air means may be the positive-displacement
Small amount of bubbles, in comparison with an arrangement gas Supply or charged air device. This enables the gas to be
only at the sides of the vessel. Further, the case of arrange blown more stably, in view of a problem of injected amount ofment only on the sides of the vessel, since the depth of water bubbles along with variation in pressure at the gas outlet
is shallow, influences of waves cannot be ignored when the 55 owing to influences of waves caused in case of using in theocean and a problem of variation in pressure acting on the gas
vessel is used in the ocean. However, at the bottom of theoutlet along with the amount of freight, that is the height ofvessel, the influences of waves are alleviated. This allows
bubbles to be stably injected, thereby effectively exerting the waterline. As a result, this can prevent impairment in fricfrictional resistance reduction effect. One piece of gas Supply tional reduction effect along with variation in the injectedor charged air means are correspondingly provided with 60 amount of bubbles owing to variational height of waves andrespect to one gas outlet. Accordingly, injecting of bubbles the height of the waterline. When the wave is high, the appar
can easily be controlled with respect to each separate gas ent waterline becomes deeper, and the frictional resistanceoutlet, and the problem of variation in inject rate of bubbles tends to increase. Accordingly, the reduction in frictionalowing to waves can also be alleviated. Further, the condition resistance by bubbles is expected. However, the conventionalof gas Supply or charged air can be controlled according to the 65 method increases the pressure at the bubble nozzle. Accord
detection result from the navigation detection means. Accord ingly, there is a phenomenon that the amount of bubbles isingly, the injecting of bubbles can finely be controlled accord conversely decreased. Further, when the amount of freight isUS 9,376,167 B2
27
increased and the waterline is deepened, the contact area of28
Moreover, according to the present invention, the relative
the hull is increased. Thus, further reduction in frictional
velocity detector is attached to a spot of the hull without
resistance is expected. However there is a problem that the receiving influences of waves and/or bubbles. Accordingly, inamount of bubbles is also decreased. In view of these phe particular, this can prevent error from being generated in thenomena, the positive-displacement gas Supply or charged air 5 relative velocity of the vessel used in the ocean. For example,
device is used; the gas Supply or charged air devices are used various types, such as an ultrasonic system, an electromag
for the respective gas outlets; the gas outlets are arranged at netic system and a heat wave system, can be considered as thethe bottom of the vessel. Accordingly, this enables a stable relative velocity detector. However, any one of these causes
amount of bubbles to be injected without receiving influences an error, with intervention of bubbles and also with influencesof waves and the draft.
10 of waves. Accordingly, attachment of the relative velocity
Further, according to the present invention, the plurality of detector to the spot without these influences can eliminate thegas outlets are arranged along the fore shape of the bottom of error, and realize an appropriate control of injecting gas.
Moreover, according to the present invention, by means of
the vessel. This enables the gas to be injected, without making
vacant and useless Surface at the bottom of the vessel. Accord
the draft detector detecting the draft of the vessel, responsive
ingly, the frictional reduction effect can be further improved. 15 to the height of waterline, the number of working gas outlets
In particular, the bottom of the vessel at the bow section and/or the inject rate of gas is increased and decreased. Thus,
corresponds to a distal end of a so-called boat shape. The the frictional resistance can finely be reduced according to theplurality of gas outlets are laterally arranged at this portion, navigational condition of the vessel. More specifically, when
and the injecting of gas is controlled. Accordingly, in particu the amount of freight to the vessel is large, the waterline rises
lar, when the relative velocity of the vessel is slow or the (becomes deeper). In this case, the contact area of the hullwaterline is shallow, the bottom of the vessel can evenly be with water is increased. In this case, increase of the number ofworking gas outlets and/or the inject rate of gas can reduce thecovered with a small amount of bubbles, and the sides of thevessel can be covered with bubbles rising in the water, thereby frictional resistance more effectively. In contrast, in a state
allowing the effect of reduction in frictional resistance to be where the amount of freight is Small, the balance is main
25 tained by ballast water, and the waterline is lowered (becomes
further improved.
Moreover, according to the present invention, the gas shallower), decrease of the number of working gas outlets
adjustment means adjusts and injects gas from the plurality of and/or the inject rate of gas can reduce the net frictional
gas outlets arranged at least at the bottom of the vessel, resistance with maintaining the balance without use of power
according to the detection result from the navigational con of the drive device in vain.
dition detection means detecting the navigational condition 30 Further, according to the present invention, the inclinationof the vessel. Therefore, rise of the bubbles can be inhibitedof the hull is detected by the inclination detector and theby the bottom of the vessel itself, the bubble retention effect number of working gas outlets laterally arranged on the vessel
can be maintained, and the frictional resistance can effec
and/or the inject rate of gas are controlled. Therefore, thetively be reduced by a small amount of bubbles, in compari frictional resistance can effectively be reduced without using
son with an arrangement of the gas outlets only on the sides of 35 the power in vain when the vessel is turning and rolling. Morethe vessel. In particular, a case where influences of waves and specifically, in a state where the one side of the bottom of thethe draft is considered, the gas outlet at the bottom of the vessel is raised owing to turning or rolling, the contact area ofvessel is mainly used, and these influences can be alleviated. the hull with water becomes smaller on the raised side than
Further, injecting of bubbles can easily be controlled by the that of the opposite sunk side. Accordingly, in order to appro
gas adjustment means with respect to each separate gas outlet. 40 priately distribute injecting of gas, it is preferable that theIn particular, in a case of use in the ocean, the problem of number of working gas outlets and the inject rate of gas bevariation in inject rate of bubbles owing to waves can also be decreased on the risen side, and increased on the opposite
alleviated by predicting variation in pressure and adjusting side. In this case control is performed only on the number ofthe blowing gas. Moreover, the gas adjustment means can working gas outlets, or only on the inject rate of gas, or on
control the blowing condition according to the detection 45 both of them simultaneously. In any event, inclination detec
result from the navigation detection means. Accordingly, the tor detects the hull and the gas adjustment means adjusts theinjecting of bubbles can finely be controlled according to injecting of gas, thereby allowing the net frictional resistancenavigational situations in comparison with a case of uni to be reduced automatically and appropriately without using
formly injecting gas, and further frictional resistance reduc power in vain.
50
Further, according to the present invention, the gas adjusttion effect can be expected.
Further, according to the present invention, the relative ment means performs adjustment at least on the plurality ofvelocity detector detects the relative velocity between the hull gas outlets injecting bubbles to the bottom of the vessel andand water, and the number of working gas outlets and/or the controls starting/stopping injecting gas according to the navi
inject rate of gas are increased and decreased according to gational condition of the vessel and/or the vessel conditions.
increase and decrease in relative Velocity. Accordingly, fric 55 In particular, in a case of the frictional resistance reduction
tional resistance can finely be reduced according to the navi effect by injecting gas cannot be expected, the injecting
gational condition of the vessel. The reduction in frictional bubbles is stopped. In a case of the reduction effect can be
resistance is determined by the relative velocity between cur expected, bubbles are injected. This prevents the power frombeing used in vain, and can effectively reduce the net fricrents in the ocean or the water flow in the river and the hull,instead of a ground Velocity where the navigational speed of 60 tional resistance. The frictional resistance at the hull is sub
the vessel is by use of the GPS or a beacon. Therefore, the stantially proportional to a square of the relative Velocity
number of working gas outlets and/or the inject rate of gas are between the hull and water. Accordingly, if the relative veloc
increased when the relative velocity is large on the basis of the ity between the hull and water is decreased, the frictional
hull and the water. The number of gas outlets and/or the inject resistance is Suddenly decreased, and the power and energy
rate of gas are reduced when the relative velocity is small. 65 consumed by the gas Supply or charged air means become
This allows the net reduction effect of the frictional resistancelarger than the frictional reduction effect. In Such a case, it is
to be increased.
desirable to stop injecting of gas from a systematical standUS 9,376,167 B2
29
point. Accordingly, when the Velocity becomes equal to aprescribed Velocity or less, and when approaching a port, theinjecting of gas is stopped. When the Velocity becomes theprescribed velocity or more, and when a prescribed time
elapsed after departing the port, the injecting gas is started.
These determinations are made by the navigational condition
detection means and/or the vessel conditions determination

30
bottom of the vessel while being retained up to the end of theconcave portion of the bottom of the vessel. The effect of theconcave portion can prevent the bubbles from being diffused
to a part with a lower water pressure even when the vessel isinclined owing to disturbance of waves and flows, and stably
facilitates reduction in frictional resistance.

Further, according to the present invention, the unevenmeans, and the injecting of bubbles are started/stopped. This profile whose sectional width is at least one with respect to theenables the control to be appropriately performed.
in the longitudinal direction with reference to the gas
Further, according to the present invention, when it is 10 heightoutletis
Accordingly, the bubbles in the water per
detected/determined that the vessel is stopped, the gas Supply taining toformed.
theinjected
air adhere to the concave portion by theor charged air means is stopped, and injecting bubbles fromthe gas outlet is stopped, the gas Supply or charged air means resistance. This allows the bubbles to flow while being
retained up to the end of the uneven profile of the bottom of
blowing gas can be stopped if the reduction in frictional thevessel.
resistance is not required. This negates use of power and 15
Further,
according to the present invention, the unevenenergy consumption in vain, and can realize africtional resis
tance reduction device for a vessel that has systematically profile may have a profile where substantially triangularshapes are laterally arranged. Since the height of the triangle
high energy efficiency and is economic.
Moreover, according to the present invention, the gas is is formed equal to or less than the height capable of being
injected from the gas outlet, and a plurality of end plates are sufficiently covered with bubbles, the bubbles actually adhere
arranged in an aft direction at Substantially ends of the bottom to the concave portion pertaining to the triangle because of theof the vessel in a longitudinal direction. Accordingly, the differential pressure. This allows the bubbles to flow while
injected bubbles can flow along the bottom of the vessel over being retained up to the end of the uneven profile of thethe entire bottom of the vessel in the water. This allows thebottom of the vessel. Moreover, since the substantially trian
frictional resistance to effectively be reduced. The operation 25 gular shapes are laterally arranged, a lot of Vertices of theof the end plate can prevent the bubbles from being distrib Substantially triangular shapes exist. This facilitates opera
uted to a part with lower water pressure, even when the vessel tion of carrying the vessel on bases under docking situations,is inclined owing to disturbance Such as waves and flows. This thereby allowing the operation to be improved.
Further, according to the present invention, the plurality of
can stably facilitate reduction in frictional resistance.
Further, according to the present invention, the plurality of 30 end plates arranged at Substantially end portion of the bottom
end plates are substantially symmetrically arranged along of the vessel in the aft direction with reference to the gas outlet
with the planar shape of the bottom of the vessel. This can also serve as stabilization means of the vessel. This further
Substantially prevent (the group of) the end plates from being improves the effect of Suppressing rolling and turning overa resistance impeding the sailing of the vessel. Moreover, this onto the side of the vessel owing to natural phenomena and aallows the gas outlets to be arranged along with the front 35 collision object, and allows the injected bubbles to flow whileplanar shape of the bottom of the vessel to the front most being retaining up to the end of the bottom of the vessel in thesurface in the proximity of the bow section, thereby facilitat water. Moreover, the effect of the plurality of end plates,
ing reduction infrictional resistance over the entire bottom of which also serve as the stabilization means, makes the vessel
the vessel.

resistant to inclination even under disturbance Such as waves

Further, according to the present invention, (the group of) 40 and flows. Even when the vessel is inclined to a certain extent,
the end plates is made into a shape analogous to the planar the effect by the end plates prevents the bubbles from being
shape of the bottom of the vessel, thereby enabling the effect diffused to a part with lower water pressure, thereby allowingof retaining bubbles to be further improved.
the frictional resistance to be stably reduced.
Moreover, the present invention may adopt a configuration
Further, the present invention negates the need of sepa
where the end plate is defined by a substantially triangular 45 rately providing the stabilization means, or allows the perfor
profile whose base is at the bottom of the vessel or a curve mance, functionality and equipment of the stabilization
Such as a quadratic function curve. This profile allows the means to be minimize, thereby enabling economic efficiencyof the vessel to be improved.
contact area with water to be decreased, and allows the frictional resistance owing to arrangement of the end plates to beMoreover, the present invention enables the equipment of
reduced, in comparison with a case of using a flat plate. This 50 the bilge keel to be saved, and allows the resistance of currents
further improves the effect of substantially avoiding the resis acting on the vessel to be reduced because the height of thetance of impeding the sailing of the vessel owing to (the group end plate is less than that of the bilge keel.
Further, according to the present invention, bubblesof) the end plates. The bubbles in the water pertaining to theinjected air flow while being effectively retaining along the injected from the gas outlet by the gas Supply or charged air
bottom of the vessel.
55 means driven by the drive device adhere to the surface of the
Further, according to the present invention, the fore and aft bottom of the vessel by the fluid effect of a difference of steps
ends of the end plate have a streamlined shape at the fore attracting the bubbles, and can flow over the entire bottom of
and/or the aft end, and thereby minimizes the water resis the vessel while being retained, thereby allowing the reductance. This allows the frictional resistance owing to arrange tion effect of the frictional resistance to be improved.
ment of the end plates to be further reduced, and the bubbles 60 Further, the present invention enables the bubbles injectedin the water pertaining to the injected air effectively flow from the gas outlet to be drawn by bubble drawing means atalong the bottom of the vessel.
the position where the bubbles leave the bottom of the vessel
Moreover, according to the present invention, the concave and start diffusion. This can avoid diffusion of bubbles in the
portion is formed at the bottom of the vessel in the longitu Water.
dinal direction, the astern direction with reference to the gas 65 According to the present invention, bubble is supplied byoutlet. This further improves the effect that the bubbles in the the gas Supply or charged air means and bubbles are injectedwater pertaining to the injected air effectively flow along the from the gas outlet arranged at the bottom of the vessel.

US 9,376,167 B2
31
Therefore, rise of the bubbles is suppressed by the bottom of

32
According to the present invention, the bubble drawing
the vessel itself. This allows the bubble retention effect to bemeans arranged at the fore part of the propeller means draws
the bubbles to be convolved into the propeller means before
maintained, and enables the frictional resistance to be effec
tively reduced by a small amount of bubbles. In particular, in convolvement, and discharges the drawn bubbles to the out
a case of using the vessel in the ocean, the influences of waves side, thereby causing the bubbles not to reach the propeller
have been incapable of being ignored. However, the influ means. This can reliably prevent bubbles from being con
volved. Further, since the bubble drawing means is arrangedences of the waves are alleviated at the bottom of the vessel,
thereby enabling the bubbles to be stably injected. Moreover, in the proximity of the propeller means, the frictional reduceffect by the bubbles injected to the bottom of the vessel
the convolvement prevention structure preventing bubbles 10 tion
sufficiently be exerted.
from being convolved into the propeller means allows the canFurther,according to the present invention, in the bubble
bubbles to escape without receiving influences of waves and drawing means,gas-liquid separation mechanism sepa
currents and without being convolved into the propeller rates the drawn the
bubbles and water from each other. Thismeans. This can prevent the efficiency of the propeller means prevents water from being mixed into the bubble drawing
from being decreased, and prevent the propulsion from being 15 means including a blower, a compressor and a pump, thereby
decreased, and allows the net reduction effect in frictional
allowing the functionality to be stably exerted. The water
force to be improved.
separated by the gas-liquid separation mechanism can be
In addition to the injecting of bubbles from the bottom of used for another application of the vessel. Such as for coolingthe vessel, injecting from a part other than the bottom of the water and an anti-rolling tank.
vessel also exerts an analogous effect. Moreover, arrange
Further, according to the present invention, the convolve
ment of the convolvement prevention structure at a part other ment prevention structure preventing convolvement ofthan the bottom of the vessel also exerts an analogous effect. bubbles is arranged after the bubble drawing means. Accord
Further, according to the present invention, the protuber ingly, even if residual bubbles having not been drawn flow out
ance having the curved surface, which is the convolvement of the bubble drawing means owing to various disturbances,prevention structure, causes the bubbles to escape, and the 25 the convolvement prevention structure causes the bubbles tobubbles are never convolved into the propeller means. This escape, and can reliably prevent the convolvement into thecan prevent the efficiency of the propeller means from being propeller means. Accordingly, the bubble drawing means candecreased, and prevent the propulsion from being decreased. be stopped and only the convolvement prevention structure
Moreover, the protuberance having the curved surface can be can be operated, in a case where the amount of bubbles isconfigured as a simple structure. Accordingly, the protuber 30 Small, or according to the vessel conditions or the naviga
ance never becomes an obstacle under docking situations. tional condition. This can prevent the efficiency of the pro
Since a flow along the bottom of the vessel smoothly changes peller means from being reduced, and prevent the propulsion
at the protuberance having the curved surface, convolvement from being decreased, in a finer manner.
ofbubbles can effectively be prevented without increasing theAccording to the present invention, when the bubble con
frictional resistance at the hull. Further, the streamline goes 35 volvement detection means detects the convolvement of thedownwards at the protuberance having the curved surface, bubbles into the propeller means, the inject condition of theand the flow velocity below the propeller means is decreased. gas outlet and/or the operating condition of the gas Supply or
Accordingly, improvement in propeller efficiency can be charged air means are changed. This can further prevent the
expected.
bubbles from being convolved, and prevent the reduction in
Further, according to the present invention, the V-shaped 40 propeller efficiency to be continued. This can also prevent
mound, which is the protuberance and laterally spreads cen vibration and noise at the propeller means along with thetered at the planar center line of the hull, can prevent bubbles convolvement of bubbles from being generated, thereby
from being convolved into the propeller means. This allows allowing damage of the propeller means to be reduced, andbubbles to effectively escape in a symmetric manner from the preventing the harmful effect on the vessel.
symmetric propeller means arranged on the planarcenterline. 45 According to the present invention, when the bubble con
Moreover, the mound has a V-shaped form. This further volvement detection means detects convolvement of bubbles
improves the effect of causing the bubbles to escape, and can into the propeller means, change of the operating condition of
prevent increase infrictional resistance of the flow along the the propeller means can increase the number of revolutions tobottom of the vessel. Further, the symmetric shape facilitates maintain the propulsion and can decrease the number of revo
manufacture.
50 lutions to reduce the convolvement of bubbles if the propul
Further, according to the present invention, the bubble sion of the propeller is decreased owing to convolvement ofprotection arranged in the proximity of the propeller means bubbles. Further, the operation condition is changed such thatprevents only bubbles reaching the proximity of the propeller the number of revolutions is decreased for addressing vibrameans from being coming into the propeller means. This can tion and noise, or the angles of blades are changed in a case of
prevent the bubbles from being convolved without impeding 55 a variable-pitch propeller, thereby changing the condition
into that with less influence against mixing of bubbles. Thisa flow of water into the propeller means.
Further, according to the present invention, at the bubble enables the influence owing to convolvement of bubbles to beprotection that has a plurality of apertures and arranged in a reduced.
According to the present application, a part of the pressur
Substantially V-shape, the apertures act as a resistance against
bubbles in a part below the propeller means where bubbles 60 ized gas and/or the exhaust gas among the residual gas from
whose distribution of velocity of flow are substantially the turbocharger can be reused as bubbles. This facilitates
V-shaped are easily convolved and are thereby capable of reduction in resistance without any need of energy for gener
effectively preventing convolvement. Moreover, the bubble ating bubbles, thereby allowing energy consumption thereof
protection has a plurality of apertures, and an area above the to be reduced. Further, control where, for example, variation
Substantially V-shaped part is vacant. Accordingly, the water 65 in vesselvelocity is reflected over time can be attuned without
flow into the propeller means is not impeded, and the propul adversely affecting the main engine. More specifically, thiscan prevent shortage of gas Supply or charged air rate, reducsive efficiency is never decreased.

US 9,376,167 B2
33
34
This
facilitates
optimizationof the energy efficiency intion in efficiency of the main engine and deterioration of theexhaust gas owing to over drawing, and also prevent analo which, for example, variation in vessel velocity and the likegous events owing to too much gas from occurring. Further, are reflected over time, without adversely affecting the main
effective use of the residual gas from the turbocharger and the engine. Accordingly, the residual gas of the turbocharger can
exhaust gas from the main engine are improved as much as effectively be used as a driving source of the gas Supply or
possible.
Further, according to the present application, optimal val charged air means.
Further, according to the present application, the exhaustues can be set for the respective conditions varying over timeon the basis of the scavenging gas pressure and the exhaust gas bypass from the turbocharger drives the electric generator
gas temperature, which are physical quantities allowing the 10 in the gas Supply or charged air means. The electric power
operating conditions represented as the heat load on the main from the electric generator drives the blower. The bubbles
engine to be grasped in the most appropriate manner, and the generated from the blower are used. Accordingly, the residual
turbocharger efficiency, which is characteristics of the turbo gas that includes high pressure and high temperature gas andcharger, and various operations can be automatically pro has a high energy value is effectively reused for a source ofcessed. Moreover, use of the setting values allows the energy 15 electric generation, among residual gases. Moreover, theconsumption efficiency utilizing the vessel resistance reduc blower is driven by the electric power. This facilitates control
tion effect using bubbles to be automatically maximized.
Further, according to the present application, the gas Sup of the number of revolutions and, in a case of plural arrange
ply or charged air and the Scavenged gas from the turbo ments, operations where the numbers of revolutions are difcharger can be reused as bubbles. This facilitates reduction in ferentiated.
Moreover, according to the present application, the exhaust
resistance without any need for energy for generating
bubbles, thereby allowing the energy consumption thereof to gas bypass from the turbocharger drives the turbine in the gas
be reduced. Moreover, the gas Supply or charged air bypass Supply or charged air means. The drive at the turbine (e.g., arate and/or the scavenging bypass rate are controlled on the coaxial configuration) drives the blower. The bubbles gener
basis of the physical quantity related to the heat load on the ated by the blower are used. Accordingly, the residual gas thatmain engine and the characteristics of the turbocharger. 25 includes high pressure and high temperature gas and has a
Accordingly, a inject gas control device perfuming control in high energy value can be effectively reused for the direct
which, for example, variation in vessel velocity and the like driving Source of the blower, among residual gases. In par
are reflected over time can be realized, without adversely ticular, the drive by the turbine directly drives the blower,
affecting the main engine. More specifically, this can prevent thereby increasing efficiency of conversion.
shortage of gas Supply or charged air rate, reduction in effi 30 Further, according to the present application, the piping
ciency of the main engine and deterioration of the exhaust gas path is arranged at above the waterline and then connected toowing to over drawing, and also prevent analogous events the gas outlet on or below the waterline. This can prevent
owing to too much gas from occurring. Further, effective use backflow of seawater from the gas outlet, thereby allowingof the residual gas (gas Supply or charged air and Scavenged
security of the main engine to be further secured in viewgas) from the turbocharger is improved as much as possible. 35 theofthedevice.
Further, according to the present application, the gas Sup
Moreover, according to the present application, the gas
ply or charged air and/or the scavenged gas are heated andSupplied to the gas outlet. This can reduce the water viscosity pressure is made to adaptively vary with respect to the plu
resistance, further improve the frictional resistance reduction rality of piping path (system) arranged for the respective gas
effect of the vessel, and still further improving reduction in 40 outlets symmetrically arranged. This enables the injecting ofenergy consumption.
bubbles from the nozzles arranged at a shallow spot and theMoreover, according to the present application, the exhaust nozzles arranged at a deep position to be substantially uni
gas from the turbocharger can be reused as bubbles. This formly controlled even in a case under rolling conditions
facilitates reduction in resistance without energy for generat (rolling) of the vessel.
ing bubbles, thereby allowing the energy consumption 45 Further, according to the present application, starting/stop
thereof to be reduced. Further, the exhaust gas bypass rate is ping Supplying the pressurized gas and/or the exhaust gas tocontrolled on the basis of the physical quantity related to the the gas outlet is controlled by adjusting the pressurized gas
heat load on the main engine and the characteristics of the rate adjustment means and/or the exhaust gas rate adjustment
turbocharger. This realizes a inject gas control device per means, according to the pressure of the pressurized gas and/or
forming control in which, for example, variation in vessel 50 the exhaust gas and the draft of the vessel. The control of thevelocity is reflected over time is realized without adversely adjustment means enables the Supply to be started when aaffecting the main engine. More specifically, this can prevent sufficient condition for injecting bubbles is realized, andshortage of gas Supply or charged air rate, reduction in effi
the supply to be stopped when the condition becomesciency of the main engine and deterioration of the exhaust gas enables
owing to over drawing, and also prevent analogous events 55 insufficient. This allows the gas Supply or charged air at anowing to too much gas from occurring. Further, effective use appropriate inject condition. An event of backflow of seawaof the residual gas from the turbocharger is improved as much ter into the main engine can be prevented.
Moreover, according to the present application, drawing
as possible.
Further, according to the present application, the gas Sup rates of pressurized gas and/or the exhaust gas are controlled
ply or charged air means is driven by the exhaust gas bypass 60 on the basis of the physical quantity related to the heat load on
from the turbocharger, and the bubbles generated from the gas the main engine and the characteristics of the turbocharger.
Supply or charged air means is used. This facilitates reduction This can continuously optimizes, as a device, the energy
in resistance without energy for generating bubbles, and efficiency pertaining to reduction in resistance by use andallows the energy consumption thereof to be reduced. More generation of bubbles by the exhaust gas, from the starting ofover, in this time, the exhaust gas bypass rate is controlled on 65 the operation of the engine, and then operation and to thethe basis of the physical quantity related to the heat load on stopping of the engine, without adversely affecting the main
the main engine and the characteristics of the turbocharger. engine.

US 9,376,167 B2
35
Moreover, according to the present application, the path isblocked properly. This minimizes a possibility of a dangerous
event that seawater comes into the main engine against theintention.

36
limiting means does not become an obstacle, thereby allow
ing the working efficiency to be improved.
Further, according to the present application, the variable
nozzle improving the gas Supply or charged air characteristicsof the turbocharger can control the opening/closing degree of
the Vane, the aperture setting and the like, responsive toincrease and decrease of the bypassed pressurized gas and theexhaust gas rate. This allows the inflow condition of theexhaust gas Supplied to the turbocharger to be preferably

According to the present application, the variable meansare controlled whenever necessary. This can always optimize
the condition of the inflow gas flowing into the turbocharger,
and improve the gas Supply or charged air characteristics. For
example, the inflow condition (direction, pressure, Velocity, 10
controlled. Moreover, in the control of the variable nozzle, theetc.) of the gas is controlled by means of a certain variable control
according to the pressurized gas andvarying according to increase and decrease of the exhaust gas exhaust isgasperformed
drawing
rates,
physical quantity related to therate. Accordingly, the turbocharger operates without receiv heat load on the main engine,
and the characteristics of theing a strong influence of the rate of the inflow gas flowing into turbocharger, thereby enabling thecontrol to be performed in
the turbocharger. Therefore, the pressurized gas can prefer 15 consideration both of the drawing of the pressurized gas or theably Supplied to the main engine without reducing the turbo exhaust gas and the condition of the main engine. Accord
charger efficiency, thereby maintaining the overall efficiency ingly, the pressurized gas can preferably be supplied to theof the main engine in a prescribed extent. Further, the inject main engine without deteriorating the characteristics of thecondition (e.g., direction, inject rate, Velocity, etc.) of the gas turbocharger. The pressurized gas and the exhaust gas can be
is controlled. This can minimize influences received from thedrawn while the overall efficiency of the main engine isnavigational condition and the like, inject the gas to desired maintained within a prescribed extent. The effect of variable
regions and positions in the proximity of the hull. That is, a nozzle improves the characteristics of the turbocharger in
preferable frictional resistance reduction effect is acquired, cases where light or heavy load other than the standard load isuseless injecting of gas is prevented, and the energy efficiency applied. This enables the bypass rate of the pressurized gas
is improved. Moreover, the gas is controlled by the limiting 25 and the exhaust gas to be drawn more.
Moreover, according to the present application, the Scavmeans having a transformable shape in order to maintain theeffect pertaining to the highly efficient injecting of gas for a enging gas pressure and the exhaust gas temperature, which
longtime. This can prevent diffusion owing to the influence of are necessarily utilized as physical quantities for grasping thethe navigational condition, and realize reduction in frictional operating condition of the main engine, is used, and the con
resistance more preferably. Further, this also allows the main 30 trol is performed on the basis of the turbocharger efficiency as
tenance to be easily performed. Therefore, an integrated com the characteristics of the turbocharger, thereby enabling thebination of these allows energy saving in the entire sailing of variable nozzle to be optimally controlled responsive to vari
the vessel.
ous conditions varying over time. Further, existing detection
Further, according to the present application, a prescribed means and the like can be used. Operations corresponding tovariable part pertaining to the variable nozzle is controlled 35 the load on the main engine can automatically be processed.
Further, according to the present application, the inject
responsive to the conditions of the pressurized gas derived
from between the turbocharger and the main engine and/or condition can be controlled, responsive to the detection result
the exhaust gas. This allows the inflow condition into the of the navigational condition detection means, in consider
turbocharger to be optimized, irrespective of increase or ation of the condition of bubbles after injecting, before inject
decrease of the drawing flow rate pertaining to the pressurized 40 ing the gas, which is Supplied from the gas Supply or charged
gas or the exhaust gas. Therefore, the pressurized gas can air means, into the proximity of the hull. This allows the gas
preferably be Supplied to the main engine without decreasing to be injected in a manner more analogous to a desirable one.
the turbocharger efficiency. That is, highly efficient drive of Moreover, the navigational conditions varying according to
the turbocharger can be realized, thereby allowing the main various scenes of the vessel that can appear on sailing can beengine efficiency to be maintained within a prescribed extent. 45 detected as numerical information by the navigational condi
Moreover, according to the present application, the inject tion detection means, and the detection result can be supplied
conditions, such as the direction in which the gas is injecting as information to another device and the like.
Moreover, according to the present application, the injectaccording to the navigational condition, the inject rate and the
Velocity, can be controlled. This allows the injecting region, rate and the inject direction injected from the gas outlet can beamount, time period, timing and the like of the gas injected in 50 controlled according to the navigational condition. For
the proximity of the hull to be preferably specified. For example, in cases of big waves, strong winds and turning of
example, the hull is inclined in various directions by receiving the vessel, the inject direction of gas is preliminarily beforces transversely and Slantly owing to waves and currents. adjusted according to the direction and inclination of the
However, the inclination is detected as the navigational con bottom of the vessel, thereby allowing the frictional resis
dition, and the inject condition is controlled responsive to the 55 tance to be efficiently reduced. Further, the inject rate of gas
inclination, thereby allowing the optimal frictional resistance may be adjusted to be small, standard and large amounts,
according to the navigational conditions, such as cases of areduction effect to be acquired.
Moreover, according to the present application, the limit slow speed in a port and the like and cruising on sailing. The
ing means for limiting the diffusion of gas is configured to be inject direction may be adjusted in the center direction withretractable. Accordingly, the limiting means is retracted in 60 respect to the bottom of the vessel and gas is locally injectedcases where the limiting means can be a navigational therein. Instead, the gas may be injected Substantially parallel
obstacle. Such as a case where the vessel without injecting gas thereto. This enables the inject condition of gas to be arbi
is sailing in shallow waters, and a case where the hull is fixed trarily operated according to the navigational condition of theunder docking situations. This can prevent the limiting means vessel, allows the frictional resistance to be reduced, thereby
from being an obstacle or a load on operation. Therefore, 65 enabling the energy consumption rate to be further improved.
Further, according to the present application, since the gas
energy-saving measures can be taken on sailing by retracting
the limiting means. In a case other than that on sailing, the outlet does not protrude, the gas outlet does not become aUS 9,376,167 B2
37
38
navigational resistance of the vessel. More specifically, there ring suddenly, and causes the bubbles to flow while retaining
is no part that receives the water resistance and increases the the bubbles in the proximity of the bottom of the vessel. On
degree of resistance by adhesion of algae and the like. This the other hand, when the diffusion limiting means is folded
facilitates further reduction infrictional resistance to be gen under docking situations, the diffusion limiting means nevererated on sailing. Moreover, this does not become a load oran 5 becomes an obstacle. Accordingly, the vessel can be fixed,
obstacle or operation under docking situations either. For and influence to be adversely affected on operations such as
example, when the hull is mounted on the blocks and the like repair of the bottom of the vessel is negated. Moreover, forwhere the hull is fixed, the gas outlet has no protrusion. example, only if the diffusion limiting means is mounted on
Accordingly, the same plane with Substantially same degree the bilge portion of the hull and slightly bent outward, theof height as that of the bottom of the vessel can be configured. 10 difference of height with the bottom of the vessel is elimi
Therefore, there is no need to consider damage and the like nated. This increases the degree of freedom of arrangement,
owing to concentration of stress. Further, when the bottom of negates the need of securing a space for retraction in the hull,the vessel is repaired, the inject nozzle can be dealt with as and facilitates maintenance. Moreover, a function of a bilge
with another part. Accordingly, the working efficiency is not keel is included into the diffusion limiting means. This candecreased either. Therefore, this also facilitates reduction in 15 contribute to stabilization of the hull in sailing.
Further, according to the present application, the retract
working hours for repair and the like.
Further, according to the present application, the Straight able diffusion limiting means may be configured to beening plate preliminarily defines the fluid path of the bubbles. expandable. This can change the degree of protrusion accord
This facilitates more preferable adjustment of the inject direc ing to increase and decrease of the inject rate of gas, preventtion of the gas. Moreover, the straightening plate can also the diffusion limiting means itself from becoming a cause ofserve as a structural element of the vessel, and can strengthen the frictional resistance and from becoming a navigational
the gas outlet. Without protrusion, the strengthen plate does obstacle by contracting at a location of shallow sea bottom.
Moreover, according to the present application, the diffu
not become load on operation under docking situations. Thatis, the straightening plate exerts an effect of an adjustment sion limiting means may droop by gravity, or be urged by aelement of the inject direction of gas and an effect of the 25 spring. This negates the need for a power source when the
structural element. Further, with respect to sailing of the diffusion limiting means operates, thereby the consumption
vessel, the bottom of the vessel has no protrusion, thereby of energy thereof to be saved. On the other hand, the self
reducing worries for an operator of the vessel.
weight of the hull is added, and thereby the diffusion limiting
Moreover, according to the present application, the diffu means is automatically retracted under docking situations.
sion limiting means adopts the retractable configuration. This 30 Accordingly, the diffusion limiting means does not become
allows the diffusion limiting means to be efficiently used an obstacle, the vessel can be fixed, and the influence toaccording to the injecting conditions of gas and the naviga adversely affect operations, such as repair of the bottom of thetional conditions of the vessel. For example, in low speed vessel, is negated.
Moreover, according to the present application, separate
sailing where the frictional resistance effect is low, injectingof gas is stopped and the diffusion limiting means is retracted 35 arrangement of pieces of diffusion limiting means in a line
in an intentional and predetermined manner. This eliminates allows the material with standard dimensions to be used, thea protrusion from the hull, and the diffusion limiting means weight of diffusion limiting means which is not so heavy isdoes not become a resistance. Further, the diffusion limiting sufficient, thereby enabling the productivity to be improved.
means can serve as a function as a resistance against rolling of Further, a configuration can be adopted that is capable ofthe hull, in addition to the bubble diffusion limiting effect, by 40 retracting only the piece of the diffusion limiting means at the
protruding from the hull. The diffusion limiting means can spot of receiving the load from the blocks under docking
also allow the hull to be stabilized by lowering the center of situations or configured in a foldable structure, reinforcement
gravity. If the diffusion limiting means can be retracted is also easy, and the configuration can prevent the damage ofaccording to the docking situations such as maintenance, the diffusion limiting means owing to the concentration of stressobstacle against operation is eliminated, thereby reducing the 45 and the like. Accordingly, the necessity of repair of the diffuload on operators. Accordingly, in view of improving effi sion limiting means itself is also reduced, thereby realizing
ciency in energy resources and operation, the present inven more efficient operation.
Further, according to the present application, the diffusion
tion is significantly useful.
Further, according to the present application, a part (the limiting means may be configured to be transformabledistal end etc.) of the diffusion limiting means can beina State 50 according to internal and/or external forces. This enables thewithout protrusion. Accordingly, the diffusion limiting means shape of the diffusion limiting means to be flexibly changed,
never becomes an obstacle under docking situations, and the in contrast to a fixed diffusion limiting means. More specifi
vessel can be fixed. Moreover, this negates a case where the cally, if application of the internal force can maintain the
diffusion limiting means acts as an obstacles and adversely expanded State, the function as the diffusion limiting means isaffecting operations such as repair of the bottom of the vessel. 55 exerted, and the bubble diffusion owing to influences of theMore specifically, the state where the diffusion limiting normal sailing maintaining a Substantially straight sailing andmeans is retracted and does not protrude by the load of the an inclination of the vessel caused in sailing and rollinghull itself when the hull is fixed can be maintained. In thiscaused suddenly is suppressed, thereby causing the bubbles tostate, the substantially same plane as the bottom of the vessel flow while retaining the bubbles in the proximity of the bot
is configured, and operation can be applied thereto as with the 60 tom of the vessel. On the other hand, the diffusion limiting
other part. Therefore, working efficiency is not impaired.
means can be transformed responsive to influences of stop
Further, according to the present application, the folded ping of the internal force and/or the external force. If the
diffusion limiting means is provided. Accordingly, the folded retraction is not especially performed, this can prevent the
diffusion limiting means is Smoothly protruded incursing and diffusion limiting means itself from being a navigational
the Substantially straight line sailing is maintained, Sup 65 resistance and from being an obstacle against under docking
presses the bubble diffusion owing to an inclination caused in situations. Moreover, for example, the internal force may benormal operation and sailing and a Swing of the vessel occur increased and the degree of protrusion is increased, therebyUS 9,376,167 B2
39
40
improving the function as the stabilization means for address can be suppressed, and the bubbles are caused to flow while
ing the rolling of the hull. Further, when the waterline is deep, the bubbles are retained around the hull. Further, the diffusion
the bubbles injected in the proximity of the hull are small and of gas is limited by the effect of the fluid. This enables thethe degree of protrusion (transformation) of the diffusion elements not to protrude from the hull, negates the need tolimiting means may be small, transformation and contraction consider the positions of blocks under docking situations,is caused by an influence of the draft (external force). This can thereby eliminating obstacle on operation. Therefore, work
prevent the diffusion limiting means from being a cause of ing hours for repair and the like can be reduced.
Further, according to the present application, the open andincrease infrictional resistance. Therefore, the present invention is more effective in view of improving efficiency in close means for closing the path when gas is not injected,
10 which is arranged in the path in the proximity of the gas outlet,
energy resources and operation.
Further, according to the present application, the diffusion may block the inflow of water when the gas Supply or charged
limiting means having a hollow structure may be adopted. air is stopped, can prevent backflow of water into the gas
This allows the diffusion limiting means to be expanded by Supply or charged air means, and thereby can prevent the airpressurization from the inside by means of a flow of fluid,
Supply pipe from being damaged. More specifically, thisSuch as gas or liquid, or powder. Moreover, after the expan 15 eliminates rust owing to moisture and fouling of marine
Sion, for example, closing of the valve can maintain the pres organisms in the path, Suppresses the increase in frictional
Sure constant. Accordingly continuous flow is not required, resistance when injecting gas, negates the need for mainte
thereby allowing the amount of energy consumption for Sup nance, and thereby enables the air Supply pipe to be used forplying the fluid to be saved. Further, the fluid can easily be a long term. Moreover, closing of the path by the open anddischarged, a short time period is Sufficient for contraction, close means can prevent the frictional resistance owing toand discharge by the self weight of the hull can be performed inflow of the water flowing into the path during sailing fromunder docking situations, thereby allowing the vessel to be being increased.
fixed in a short time period.
Further, according to the present application, in a case of
Further, according to the present application, the hollow arranging the navigational condition detection means in the
structure can serve as the function of the air Supply pipe and 25 water, arrangement at a part without receiving influencestransfers the gas generated by the gas Supply or charged air from the bubbles injected from the gas outlet negates themeans to the gas outlet. In this case, the hollow structure is influence of disturbance of bubbles, and allows stable detec
expanded by pressurization of gas, and can Suppress the tion of various conditions. Moreover, this can prevent foulingbubble diffusion caused by an inclination of the vessel, and of organisms that dwell at seashore, Such as barnacles, andalso serve as the function of the diffusion limiting means. 30 easily reproduce because of existence of air, thereby allowing
Moreover, for example, the hollow structure can directly be the navigational condition to be stably detected for a longconnected to the gas supply or charged air means or the air term.
Supply pipe, thereby allowing the path of the injected gas to be
BRIEF DESCRIPTION OF THE DRAWINGS
formed. This allows both the function as the diffusion limiting
means and the function of the air Supply pipe to be exerted. 35
Further, according to the present application, the diffusion
FIG. 1 (a) is a side view of a vessel to which a frictional
limiting means may have a hollow structure that is configured resistance reduction device for a vessel of an embodiment ofwith an elastic material and the inside is hollow. This allows
the present invention is applied: FIG. 1 (b) is a top view of thethe inside of the hollow structure to be pressurized, be same vessel; FIG. 1 (c) is a bottom view of the same vessel;
enlarged and contract by means of the power of fluid accom 40 FIG. 2 (a) is a side view of a blower used for the frictional
panying the sailing of the vessel, without separately injecting resistance reduction device for a vessel of the embodiment of
fluid into the hollow structure. Accordingly, the force of the the present invention; FIG. 2 (b) is a side view of the same
fluid accompanying the sailing of the vessel can be utilized blower; FIG. 2 (c) is a diagram showing the internal structure
and thereby allows the diffusion limiting means to be formed. of the same blower;
This negates the need for a device and the like for injecting 45 FIG. 3 is a perspective view of the gas outlet used for thegas and the like into the hollow structure, thereby allowing the frictional resistance reduction device for a vessel of theenergy to be effectively utilized. Moreover, unless the vessel embodiment of the present invention;
FIG. 4 is a conceptual view showing operation of the gas
is sailing, the fluid force cannot be generated. This allows thehollow structure to contract under docking situations, and the outlet used for the frictional resistance reduction device for a
fixation of the vessel can immediately be performed. The 50 vessel of the embodiment of the present invention;
FIG. 5 is a sectional view showing attachment of the gas
diffusion limiting means never becomes an obstacle, and does
not influence operations such as repair of the bottom of the outlet, which is used for the frictional resistance reduction
vessel.
device for a vessel of the embodiment of the present inven
Moreover, according to the present application, the degree tion, to the bottom of the vessel;of protrusion of the diffusion limiting means can be adjusted 55 FIG. 6 is a sectional view showing another manner of
responsive to starboard and port inclinations of the hull. For attachment of the gas outlet, which is used for the frictional
example, the diffusion limiting means may be protruded at the resistance reduction device for a vessel of the embodiment ofbottom of the vessel on the side where the waterline becomesthe present invention, to the bottom of the vessel;
shallow owing to the inclination, thereby enabling diffusion
FIG. 7 is a control block diagram used for the frictionalof gas along with the inclination to be limited. Accordingly, 60 resistance reduction device for a vessel of the embodiment of
the frictional resistance reduction effect significantly suitable the present invention;
FIG. 8 is a sectional view of a shear force sensor used forfor the sailing conditions can be attained.
Further, according to the present application, the limiting the frictional resistance reduction device for a vessel of theflow generation means may generate the flow limiting the embodiment of the present invention;diffusion of gas. Accordingly, the so-called pseudo wall (end 65 FIG. 9 is a bottom view of a vessel to which a frictional
plate) can be formed, the bubble diffusion caused by the resistance reduction device for a vessel of a second embodi
diffusion of injected bubbles and the inclination of the vessel ment of the present invention is applied;US 9,376,167 B2
41
42
FIG.
28
is
a
conceptual
view
showing operation of an air
FIG. 10 (a) is a side view of a vessel to which a bubble
retention device for a vessel of an embodiment of the present nozzle used for a bubble convolvement prevention device of ainvention is applied: FIG. 10 (b) is a top view of the same vessel according to still another embodiment of the present
invention;
vessel; FIG. 10 (c) is a bottom view of the same vessel;
FIG. 11 is a sectional view of the hull according to an 5 FIG. 29 is a diagram showing distribution of velocity ofembodiment of the present invention taken along line X-X (of flow of water at a propeller of a vessel according to yet
another embodiment of the present invention;
FIG. 10);
FIG. 30 is a bottom view of a vessel to which a bubble
FIG. 12 is a sectional view of the hull according to anotherembodiment of the present invention taken along line X-X (of 10 convolvement prevention device of the vessel is applied
according to still another embodiment of the present inven
FIG. 10);
FIG. 13 is a sectional view of the hull according to yet tion;
FIG.31 is a sectional view principally showing a gas-liquid
another embodiment of the present invention taken along line
separation system used in another embodiment of the present
X-X (of FIG. 10);
FIG. 14 is an enlarged view of a broken line Y part of FIG. 15 invention;
FIG. 32 is a bottom view of a vessel to which a bubble
11 according to yet another embodiment of the present invenconvolvement prevention device of the vessel is applied
tion;
FIG. 15 is a sectional view of the hull according to still according to still another embodiment of the present inven
another embodiment of the present invention taken along line tion;
FIG.33 is a conceptual view showing operation of an air
X-X (of FIG. 10);
FIG. 16 is a sectional view of the hull according to yet intake used for a bubble convolvement prevention device of aanother embodiment of the present invention taken along line vessel according to yet another embodiment of the present
invention;
X-X (of FIG. 10);
FIG. 17 is a conceptual view showing a state of retaining of
FIG. 34 (a) is a perspective view of a bubble protection
bubbles in a case where end plates according to an embodi 25 plate used for a bubble convolvement prevention device of ament of the present invention are arranged;
vessel of another embodiment of the present invention: FIG.
FIG. 18 is a conceptual view showing a state where bubbles 34 (b) is a rear elevation view of the bubble protection plate:
FIG. 35 is a diagram sectionally showing a inject gas con
flowing when a vessel is sailing in a case of arranging end
plates according to an embodiment of the present invention 30 trol device according to one embodiment of the present inven
whose fore and stern have streamline shapes;
tion and an overview of a vessel equipped with this device;
FIG. 19 is a sectional view conceptually showing a state of
FIG. 36 pertains to an embodiment where a inject gas
retaining bubbles when a vessel whose bottom has a triangu control device according to the embodiment of the present
lar uneven profile in a sectional view is sailing, according to invention is applied to a vessel used in the ocean; FIG. 36 (a)still another embodiment of the present invention;
35 shows a side sectional view of the vessel; FIG. 36 (b) shows
FIG. 20 is a sectional view conceptually showing a state of a top view thereof;
FIG.37 is a system diagram showing a system bypassing a
retaining bubbles at a vessel having a configuration including
a mound that has a wing profile in a sectional view and turbocharger according to an embodiment of the present
arranged at the bottom of the vessel when the vessel is sailing, invention;according to still another embodiment of the present inven 40 FIG. 38 is a diagram showing an actual relationshipbetween main engine loads and turbocharger efficiency
tion;
FIG. 21 is a sectional view conceptually showing a state of according to an embodiment of the present invention;
FIG. 39 is a block diagram showing an arrangement ofretaining bubbles at a vessel whose bottom has a configuration having agentle step profile toward the Stern in a sectional devices according to this embodiment, various sensors
view when the vessel is sailing, according to yet another 45 acquiring basic data of control according to the present appli
cation, actuators and the like for the sake of realizing theembodiment of the present invention;
FIG. 22 is a sectional view for illustrating a configuration control of the present invention;
FIG. 40 is a control block diagram for illustrating a control
of a gas-liquid separator in a bubble retention device accord
system of the present application;
ing to another embodiment of the present invention;
FIG.23 is a conceptual view showing a methodofusing the 50 FIG. 41 is a diagram sectionally showing an overview of agas-liquid separator in the bubble retention device according vessel equipped with a frictional resistance reduction device
for a vessel according to an embodiment of the present invento another embodiment of the present invention;
FIG. 24 is a conceptual view showing a method of using a tion;
FIG. 42 is an enlarging diagram principally showing a
gas-liquid separator in a bubble retention device according to 55 variable
nozzle according to an embodiment of the present
another embodiment of the present invention;
invention;
FIG. 25 is a diagram showing a situation pertaining to use
FIG. 43 is a characteristics diagram showing an example ofof the gas-liquid separator in the bubble retention device relationship between a main engine load and an efficiency ofaccording to another embodiment of the present invention;a turbocharger according to presence or absence of a variable
FIG. 26 (a) is a side view of a vessel to which a bubble 60 nozzle according to an embodiment of the present invention;
convolvement prevention device of the vessel is applied
FIG. 44 is a block diagram showing an arrangement of aaccording to sill another embodiment of the present inven turbocharger and peripheral elements according to antion; FIG. 26 (b) is a top view of the same vessel; FIG. 26 (c) embodiment of the present invention;
is a bottom view of the same vessel;
FIG. 45 is a control block diagram of control means
FIG. 27 is a block diagram of a bubble convolvement 65 according to an embodiment of the present invention;
FIG. 46 is a sectional view showing a concept of a gas
prevention device of a vessel of yet another embodiment of
the present invention;outlet according to an embodiment of the present invention;

US 9,376,167 B2
44
43
FIG. 47 is a transparent perspective view of a gas outlet present invention is applied to a vessel used on ocean. FIG. 1
including a straightening plate according to an embodiment (a) is a side view of the vessel. FIG. 1 (b) is a top view thereof.
FIG. 1 (c) is a bottom view thereof. In FIG. 1, a principalof the present invention;
FIG. 48 is a sectional view of a vessel including a retract configuration is exposed for the sake of illustration.
Blowers 11, 12, 13, 14 and 15 as gas supply or charged air
able diffusion limiting section as diffusion limiting means
capable of being stored according to an embodiment of the means are arranged in a line on a deck 2 of a vessel 1. These
blowers 11, 12, 13, 14 and 15 are arranged in casing in orderpresent invention;
FIG. 49 is an enlarged view of a retractable diffusion lim to avoid splash of seawater broken at the bow on the deck 2.
iting section (broken line part in FIG. 48) as the diffusion Air, as gas, is taken from a side opposite to the traveling
limiting means capable of being stored according to an 10 direction of the hull for the sake of avoiding the splash as
much as possible.
embodiment of the present invention;
The air taken into the blowers 11, 12, 13, 14 and 15 are
FIG.50 is an enlarged view/showing another embodimentof a retractable diffusion limiting section (broken line part in pressurized, passes through air supply pipes 16, 17, 18, 19 and
FIG. 48) as the diffusion limiting means capable of being 20 having bent portions, and guided into gas outlets 21, 22.
stored according to another embodiment of the present inven 15 23, 24 and 25 arranged in the proximity of the bottom3 of thevessel. In a case of this embodiment, the gas outlets 21, 22, 23.
tion;
FIG. 51 is a sectional view of a vessel including a bending 24 and 25 are arranged Substantially in a line, symmetricallydiffusion limiting section as a diffusion limiting means with respect to a planar center line CL of the hull 4, in fore ofcapable of being stored according to an embodiment of the the bottom 3 of the vessel. The gas outlets 21, 22, 23, 24 and
25 are arranged on the bottom 3 of the vessel is because ofpresent invention;
FIG. 52 is an enlarged view of a bending diffusion limiting intentions that allow injected bubble to stay longer around thesection (broken line part in FIG. 51) according to an embodi bottom 3 of the vessel and alleviate variation in pressure
owing to waves and the like. The arrangement thereof infore
ment of the present invention;
FIG. 53 is a sectional view of a vessel including a bending of the bottom 3 of the vessel is adopted in order to make thediffusion limiting section as a diffusion limiting means 25 injected bubbles stay over the entire bottom of the vessel 3 ascapable of being stored according to another embodiment of much as possible.
The arrangement of the gas outlets 21, 22, 23, 24 and 25
the present invention;
FIG. 54 is an enlarged view of a bending diffusion limiting Substantially in a line simplifies the configuration, and also
section (broken line part in FIG. 53) according to another facilitates arrangement of the blowers 11, 12, 13, 14 and 15,
30 the air supply pipes 16,17.18.19 and 20 and the like arranged
embodiment of the present invention;
FIG.55 is a sectional view of a vessel including a diffusion corresponding thereto. Further, in this example, the number
limiting means transformable according to internal force/ of gas outlets 21, 22, 23, 24 and 25 is five, which is an odd
external force pertaining to an embodiment of the present number. Accordingly, arrangement of the center one (gasoutlet 23) on the planar center line CL can realizes one spot
invention;
FIG. 56 is a side view of a vessel including a diffusion 35 injecting of bubbles with ability of the vessel 1 to hold alimiting means of another embodiment transformable accord straight line.
End plates 5, 5, 6, 6', 7 and 7", which guide the bubbles
ing to internal force/external force pertaining to the embodi
injected from the gas outlets 21, 22, 23, 24 and 25 so as not toment of the present invention;
FIG. 57 is a side view of a vessel including a diffusion dissipate the bubbles, are arranged on the bottom 3 of thelimiting means of still another embodiment transformable 40 vessel also symmetrically with respect to the planar center
according to internal force/external force pertaining to the line CL of the hull 4. In addition thereto, shear force sensors
50,51,52.53 and 54, which are shear force detectors detecting
embodiment of the present invention;
FIG.58 is a sectional view of a vessel including a diffusion shear forces acting on the hull 4 owing to seawater andlimiting section adjusting the degree of protrusion according bubbles, are arranged on the bottom 3 of the vessel on theto inclination of starboard and port as diffusion limiting 45 Stern side.
Further, relative velocity sensors 55 and 56, as relativemeans capable of being stored according to an embodiment of
Velocity detectors, are arranged on the stern side. Anotherthe present invention; andFIG. 59 is a sectional view of a vessel including limiting relative velocity sensors 57 are arranged on the sides 8 of theflow generation means according to an embodiment of the vessel. The relative velocity sensors 55 and 56 are arranged
50 apart from the gas outlets 21, 22, 23, 24 and 25. The relative
present invention.
velocity sensors 57 are arranged on a spot on the sides 8 of theBEST MODE FOR CARRYING OUT THE
vessel without influence of bubbles even if the spots are in theproximity. In particular, the relative velocity sensors 57 are
INVENTION
arranged at lower parts away from influence of waves on the
A best mode for carrying out the present invention will 55 side 8 of the vessel. These relative velocity sensors 55, 56 andhereinafter be described with reference to the drawings using 57 adopt ultrasonic system, are capable of being used underembodiments. Hereinafter, an extent necessary for descrip water, and reduce influences owing to waves and currents.
Further, video cameras 58 and 59, which monitor condition for the sake of attaining the object of the present invention will schematically be shown. An extent necessary to tions of the injected bubbles, are arranged at fore and aft parts
describe an applicable part of the present invention will prin 60 of the bottom 3 of the vessel. Images taken by the video
cipally described. A part on which the description is omitted cameras 58 and 59 are monitored by a person, and thereby
being utilized for analyzing inject conditions of the bubbles.
is pursuant to conventional techniques.
FIG. 2 is a detailed diagram showing the blowers 11, 12.
First Embodiment13, 14 and 15. FIG. 2 (a) shows a front view. FIG. 2 (b) shows
65 a side view. FIG. 2 (c) shows a sectional view partially rep
FIG. 1 (a) shows an embodiment where a frictional resis resenting an internal structure. The blowers 11, 12, 13, 14 andtance reduction device for a vessel of an embodiment of the
15 are Roots-type positive-displacement blowers, and adopt a

US 9,376,167 B2
45
structure where an inverter-type motor 60 as the drive device
drives two rotors 62 and 63 in the blower via a belt 61, the air
taken between the blower interior wall 64 and the rotors 62

46
into a Substantially right angle and spread, and injected via
perforated plates 72 and 73 arranged in series in a displaceda.

FIG. 5 shows a sectional view where the gas outlet 21 of
and 63 is compressed as the rotors 62 and 63 rotate, andsupplied. Since the blowers 11, 12, 13, 14 and 15 are the this embodiment is attached to the bottom 3 of the vessel. In
positive-displacement type, the blowers are capable of Sup this figure, for the sake of simplicity of description, a typicalplying stably a predetermined rate of air even with previous example of the plurality of air Supply pipes, gas outlets andvariation in pressure. Although the Roots-type blower is the the like is shown. The chamber 70 is arranged so as to pro
same positive-displacement type, the Roots-type blower is trude from the plane of the bottom 3 of the vessel. The air
supply pipe 16 runs through the bottom 3 of the vessel and isdifferent from the piston type in that the Roots-type blower 10 connectedto the chamber 70. The inject port 76 opens towardpressurizes air Substantially continuously and thereby
downstream direction with respect to the water flow. A
reduces pulsing, and can eliminate a tank and the like for aresistance
reduction plate 80 is arranged at the front surface of
Smoothing pressure. Further, the rotation is Smooth and vibra the chamber
70, thereby allowing a configuration in consid
tion and noise are reduced. Accordingly, even with the 15 eration that the chamber 70 does not become a resistancearrangement of blowers 11, 12, 13, 14 and 15 on the deck 2. owing to the water flow.
resonance cannot easily occur in the cabins therebelow.
FIG. 6 shows another embodiment of attachment of the gas
FIG. 3 is a perspective view conceptually showing a outlet 21 to the bottom3 of the vessel. In this another embodi
detailed configuration of the gas outlets 21, 22, 23, 24 and 25. ment, the shape of the bottom 3 of the vessel is designed in
For the sake of simplicity of description, FIG. 3 shows a consideration that the shape forms a substantially same plane
typical example of the plurality of air Supply pipes and gas surface even if the chamber 70 intervenes. In this case, it isoutlets. The air blown from the blower via the air supply pipe unnecessary to provide the resistance reduction plate 80.
16 is bent at right angle at a chamber 70 of the gas outlet 21 which has been provided in the above embodiment. However,connected to the air Supply pipe 16. A distribution component considerations are taken such that a part of the bottom3 of the
71 having triangular profile for dispersing the blown air is 25 vessel in the downstream side after the gas outlet 21 is con
arranged immediately below the connection part of the air figured as a curved surface, thereby allowing the bubbles
Supply pipe 16. A configuration is adopted according to which injected from the inject port 76 to smoothly flow, to easily
the air is bent at right angle at this part and dispersed laterally adhere to the bottom 3 of the vessel and not to increaseby the distribution component 71. As the air is bent at right resistance.
angle, the air tends to uniformly spread along directions in a 30 The above embodiment shown in FIG. 5 exerts an advanhorizontal plane. However, the air tends to flow only toward tageous effect that realizes easy attachment to the bottom3 ofperforated plates 72 and 73 in front thereof by presence of the vessel, including posterior attachment of the gas outlet 21.
In the another embodiment shown in FIG. 6, it is unnecessaryinterior walls of the chamber 70 in the recess and at the right,
left, top and bottom. Here, presence of the distribution com to especially provide the resistance reduction plate 80 and theponent 71 further uniformizes the lateral distribution of the air 35 like, exerting an advantageous effect expecting that increase
with respect to the perforated plates 72 and 73.
in frictional resistance owing to attachment of the gas outlet
A lot of perforations 74 and 75 are formed at the perforated 21 can be Suppressed.
plates 72 and 73. The positions of the perforated plates 72 and
FIG. 7 is a control block diagram of this embodiment.
The vessel conditions determination unit 100 includes a
73 are laterally displaced from each other, thereby forming an
arrangement with perforations in a displaced manner. This 40 GPS 101 detecting the location of the vessel, a fuel measureembodiment shows an example using two perforated plates ment unit 102 measuring fuel consumption of engines of the
72 and 73. Instead, the number thereof may be another num vessel, and an engine operation detector 103 detecting opera
ber, such as three or four. Since perforated plates 72 and 73 are tional conditions of the engines of the vessel. The vessel
arranged so as to displace the positions of the perforations, the conditions determination unit 100 specifically determines theperforated plates 72 and 73 function as a so-called baffle 45 present conditions of the vessel, and determines the present
plates, which bend the airflow to provide resistance. Accord conditions that vary in a small degree on sailing or vary
ingly, in addition to further uniformization of the air in the gradually. For example, the GPS 101 grasps the location oflateral direction, the air in the vertical direction is also uni
the vessel on a map, and detects a distance to a port or aformized, thereby enabling the air to be injected from a inject destination, an absolute velocity with respect to the ground50 and the like.
port 76 on a front surface.
These are used for determining which locating or position
Here, the perforated plates 72 and 73 are manufactured bycontinuously making round perforations on a corrosion resis on the map the bubble are injected and stopped. The measuretant sheet metal. Such as stainless steel by a press, and the ment of the absolute velocity with respect to the ground is also
arrangement with displaced perforation positions can be real used for the sake of complementing the relative velocity
ized by cutting. This offers excellent productivity. If config 55 sensors 55, 56 and 57. The fuel measurement unit 102 mea
ured with a stainless material, since the perforations are Sures how the engines consumes fuel per prescribedtime, andround, edge portions are omitted, nearly preventing the stress also used for stopping the injecting of bubbles if the fuelfrom being concentrated when being pressed, in contrast to a consumption efficiency becomes lower than a prescribed fuelcase with square perforations. This alleviates progress of consumption efficiency. The engine operation detector 103 isstress corrosion from the edge parts, even if used in seawater. 60 used for acquiring information Such as detection of operating
The perforated plates 72 and 73 may be manufactured by conditions of the engines of the vessel, stop of injecting
using resin and by means of molding. In a case of using the bubbles when the engines stop operation, or start of injecting
resin, the shapes of the perforations are arbitrary in view of bubbles a lapse of a prescribed time after operation is started.
corrosion. However, in view of molding, round perforations The engine operation detector 103 is also used for detecting
65 the numbers of revolutions of the engines and changing theare preferable.
FIG. 4 a conceptual view showing effects of the configu number of working gas outlets and/or the inject rate ofration where the air guided by the air supply pipe 16 is bent bubbles. In addition thereto, the vessel conditions determina

US 9,376,167 B2
47
tion unit 100 further includes means for determining situa
tions where the vessel resides, such as detectors for outputs ofthe engines, a gyro, a radar and means for measuring theamount of freight and condition of ballast water, and can beused for controlling injecting of bubbles according to the48
bubbles stay at the bottom3 of the vessel are imaged by video
cameras 58 and 59. The images are utilized for analyzing andexamining conditions of injecting air.

purposes.

25 downstream from the bottom 3 of the vessel. In order to

The navigational condition detector A110 includes relative
velocity sensors 55, 56 and 57; a draft sensor 111 detecting

At the bottom3 of the vessel, the shear force sensors 51,52,

53.54 and 55 are attached to the gas outlets 21, 22, 23, 24 anddeepen analysis of variation in shear force owing to injectingof bubbles, a corresponding number thereof are attached.
the draft level of the hull; and an inclination sensor 112
Signals from the shear force sensors 51, 52,53,54 and 55 aredetecting so-called rolling, which is a lateral inclination with 10 fed
to the comparator 140. The signals are compared
respect to the traveling direction of the hull. Separately there withback
shear
values preliminarily set by the condition
from, the shear force sensors 51, 52,53,54 and 55 configure setting unit force
130. The operating conditions of the blowers 11,
a navigational condition detector B115. These navigational
condition detectors A and B115 detects physical quantities 12, 13, 14 and 15 are finely adjusted via the controller 150
that relatively easily vary as the vessel is sailing, or for the 15 pursuant to a prescribed rule, an algorithm and a constantssake of changing the quantities. The configurations of shear according to the deviations. Further, the relative velocities
between the hull and seawater are detected by the relative
force sensors 51, 52, 53 and 54 will be described in detailed
later. In addition thereto, the navigational condition detection velocity sensors 55, 56 and 57, subjected to a prescribed
statistical process, and the representative value is transmitted
unit further includes sensors detecting swaying (swaying),
pitching (pitching), Surging (Surging), heaving (heaving) and to the comparator 140. Signals from the draft sensor 111 andyawing (yawing) of the hull 4.
the inclination sensor 112 are also transmitted to comparator
An oceanographic condition determination unit 120 140.
First, the comparator 110 compares the processed repre
includes a wave sensor 121, a wind sensor 122 and a current
sensor 123. The wave sensor 121 detects wave heights, direc sentative value by the relative velocity sensors 55, 56 and 57
tions, periods of waves and the like. The wind sensor 122 25 and the condition setting value preliminarily set by the con
dition setting unit 130 with each other. For example, when thedetects wind velocities, directions of winds and the like. The
relative velocity of the hull exceeds the setting value, controls
current sensor 123 detects current velocities, directions,heights of currents and the like. In addition thereto, the can be performed including increase of the number of work
oceanographic condition determination unit is used for con ing gas outlets, increase of the amount of bubbles, andsidering information on waves, winds and currents and fur 30 increase both of them according to the deviations. When thether the weather and the like, for example, stopping injecting relative velocity becomes lower than the setting value, conof bubbles when the oceanographic condition is stormy, and trols can be performed including decrease of the number ofworking gas outlets, decrease of the amount of bubbles, andinjecting bubbles when the condition recovers.
Such information from the vessel conditions determination
decrease of both of them. When decreasing the number ofunit 100 and information from the oceanographic condition 35 working gas outlets, it is preferable to stop outer gas outlets.
For example, the gas outlets 21 and 25 are stopped, or thedetermination unit 120 are transmitted to a condition setting
unit 130. The condition setting unit systematically sets con gas outlets 21 and 22 and the gas outlets 25 and 24 areditions for injecting bubbles to the bottom3 of the vessel. The stopped. Likewise, the inject rates of bubbles are controlled.
conditions include starting/stopping of injecting bubbles, The inject rate of bubbles of gas outlets 21 and 25 arewhich gas outlets 21, 22, 23, 24 and 25 are caused to inject 40 decreased or increased to the same degree. Further, the inject
bubbles, how the inject rate is, how the timing of injecting is, rate of bubbles of gas outlet 22 and 24 are decreased or
how the temporal bubble inject sequence is composed, and increased to the same degree. Thus, symmetrical arrangement
when the injecting is started and when the injecting is of the gas outlets with respect to the planar center line CL of
stopped. In the setting unit, the conditions for injecting the hull and the symmetrical control of the inject rates of
bubbles are set such that shear forces acting on the hull, the 45 bubbles can acquire a uniform frictional resistance reduction
relative velocity of the hull, the draft, the inclination and the effect, in a case where the vessel is sailing in a straight line,
like are also considered. Condition setting for control accord which can frequently occur. Accordingly, ability of the vessel
ing to these signals is also performed. The condition setting to hold a straight line can be maintained, and fuel consump
unit performs condition setting according to a condition set tion is decreased. Further, this facilitates the circuit configu
ting instruction 131 for reducing the frictional resistance, and 50 ration and the control method of the control device.
further performs condition setting according to condition set
The comparator 140 compares a value detected by the draft
ting instruction 132 for adjusting the waterline level by means sensor 111 and a condition setting value preliminarily set by
the condition setting unit 130. For example, when the waterof injecting bubbles, which will be described later.
A comparator 140 compares signals according to the set line of the hull 4 exceeds the setting value (when the amountting by the condition setting unit 130. The blowers 11, 12, 13, 55 of freight is large and the draft rises), controls are performed
14 and 15 are controlled via a controller 150. These compara including increase of the number of working gas outlets,
tor 140 and controller 150 collectively configure a controller. increase of the amount of bubbles or increase both of them
The controller 150 also controls valves 161,162,163,164 andaccording to the deviation. When the waterline falls (the165 arranged on the discharge side of the blowers 11, 12, 13, freight is unloaded and the vessel is in a condition of ballast
14 and 15. These are added for the sake of acquiring a desired 60 water), controls are performed including decrease of the num
air rate by adjusting these valves 161,162, 163, 164 and 165, ber of working gas outlets, decrease of the amount of bubbles
when controlling air rate lower than the control ranges of the or decrease of both of them. In cases of decrease, it is prefermotors by means of inverters of the blowers 11, 12, 13, 14 and able to control in an analogous fashion to that described
15, and when quickly adjusting the waterline level using the above.
signal from the draft sensor 111. As to conditions where 65 When swells come, the valves 161,162, 163, 164 and 165
bubbles are injected from the gas outlets 21, 22, 23, 24 and 25, are controlled using signals from the draft sensor 111, and theinject conditions of the bubbles and conditions where the pressures acting on the gas outlets 21, 22, 23, 24 and 25 areUS 9,376,167 B2
49
finely adjusted by increasing or decreasing in an immediatemanner, thereby further alleviating variation in inject rate of50
24 and 25 are controlled. When the shear force is greater than
the setting value, or deviation is large, control is performed so
bubbles.
as to increase inject rate of bubbles from the gas outlets 21 andThe comparator 140 compares an inclination value of the 25. When the deviation is small, control is performed so as to
the rate. The feedback control acquires a desired
hull detected by the inclination sensor 112 and a condition 5 decreasesetting value preliminarily set by the condition setting unit condition-set shear force. The detection values of the shear
130 with each other. For example, the inclination of the hull force sensors 51, 52,53,54 and 55 are also used as indicators
the reduction effect of the frictional resistance.
exceeds the setting value owing to turning or rolling of the forInverifying
Summary, control of starting/stopping injecting gas
vessel, the inject spots of the gas outlets are changed or the includes
a case mainly pursuant to determination by the ves
amount of bubbles is increased or decreased according to the 10 sel conditions
unit 110, a case pursuant todeviation. For example, the hull is inclined to the left viewed determination bydeterminationtheoceanographic
determinationfrom the traveling direction, the right side of the bottom of the unit 120, and a case pursuant to thecondition
detection
result of thevessel is elevated. In this case, the frictional resistance can benavigational
condition
detectors
A
and
B115.
the case
effectively reduced without wastefully injecting bubbles by pursuant to the vessel conditions determinationIn unit
110.
performing controls including increase of the number of 15 injecting of bubbles is stopped when the GPS 101 determinesworking gas outlets on the left where an apparent waterline that the vessel is approaching a port or a destination, injecting
rises, increase of the inject rates thereof or increase both of is started when leaving the port, injecting is stopped when thethem and performing controls including decrease of the num vessel is approaching waters where is a Swirling current
ber of working gas outlets on the right, decrease of the inject region, injecting is started when the vessel is leaving therates thereof or decrease of both of them. The inclinationwaters, injecting of bubbles is stopped when operations of thesensor 112 can be used not only for controlling injecting of engines are stopped, and injecting of bubbles is started abubbles but also for ballast water adjustment that detects the predetermined time after the engines start. When the fuelconsumption efficiency detected by the fuel detector 102
inclination of the hull 4 and maintains the balance in a sharedbecomes below a predetermined one, injecting of bubbles area.
FIG. 8 representatively shows a schematic overview of the 25 stopped. When it is estimated that the fuel consumption effi
ciency is improved, injecting of bubbles is started. When theshear force sensor 51.
oceanographic condition determination unit 120 determines
A detection plate 1200 is arranged at the substantially same that
it is stormy Such as a typhoon and rough weather, inject
height as the bottom 3 of the vessel. The detection plate 1200 ing ofis configured so as to be suspended by leaf springs 1201 and started. bubbles is stopped. When it recovers, injecting is1202. The leafsprings 1201 and 1202 are supported by pivots 30 Further, when the wave height detected by the wave sensor
1203 and 1204. A detector 1205 is attached to the detection
becomes a prescribed value or more, injecting of bubbles isplate 1200. The other end of the detector 1205 is fixed to a stopped; when the wave height becomes a prescribed value orcasing 1206. When a flow occurs, distribution of velocity of less, injecting is started. The detection results of the naviga
flow, which is as shown in the lower part of FIG. 8, is gener tional condition detectors A and B are compared with a set
ated on a surface of the detection plate 1200. The leaf springs 35 preset value; on the basis of magnitude of deviation, injecting
1201 and 1202 are bent according to the shear force acting on is stopped when the deviation becomes a predeterminedthe detection plate 1200 by distribution of velocity of flow, threshold or less, and injecting is started when the deviation
thereby displacing the detector 1205.
exceeds the threshold. For example, the values from the rela
The displacement of the detector 1205 is electrically tive velocity sensors 55, 56 and 57 are statistically processed
detected, and the shear force is detected. The faster the flow, 40 and the representative value is transmitted to the comparator
the higher the detection value becomes. The slower the flow,
140. When the velocity of the vessel 1 is decreased and thethe lower the detection value becomes. In a condition where
value becomes lower than a prescribed threshold set by the
bubbles are mixed in seawater, the shear force acting on the condition setting unit 130, the injecting of bubbles aredetection plate 1200 is decreased and the detection value is stopped; when the value exceeds the value, the injecting isdecreased in comparison with a condition only with seawater 45 started. On the basis of temporal variation in statisticallywhere bubbles are not mixed. A condition where bubbles areprocessed representative value from the relative velocity sen
mixed and effectively acting on the bottom3 of the vessel can sors 55, 56 and 57, when the vessel 1 starts moving andbe estimated by preliminarily measuring a relationship accelerates, the threshold is set to be reduced and bubbles are
between a relative velocity with seawater where bubbles are injected a little earlier. When the frictional resistance reducnot mixed and a shear force and a relationship between the 50 tion effect is effectively exerted and the vessel is decelerated,amount of bubbles mixed therein, a relative velocity and a the threshold may be reset upward and injecting of bubbles
shear force. Further, a frictional resistance acting on the bot may be stopped a little earlier because the speed is decreased
tom3 of the vessel or the entire hull can be estimated from theand bubbles still stay at the bottom 3 of the vessel.
shear force. The shear force can be measured more accurately
As to the conditions for starting/stopping injecting gas,by increasing the number of the shear force sensors. However, 55 control may be performed according to precedence. Whenalso in an economic aspect, the entire state can be estimated detection error, failure oran unpredictable event occurs, con
by arranging a plurality of sensors in a limited area in the trol may be performed complementarily using another con
bottom 3 of the vessel.
dition. In any event, injecting of bubbles can be realized by
In this embodiment, the values from the shear force sensors
starting/stopping injecting of bubbles under a prescribed con
51, 52,53,54 and 55 are statistically processed by the navi 60 dition in consideration of an actual frictional resistancegational condition detector B115, and the representative reduction effect, or stopping injecting of bubbles whenvalue is fed back to the comparator 140. The comparator 140 detecting/determining that the vessel is stopped.
compares the fed back representative value of the shear force
Second Embodimentsensors and the condition setting value set by the condition
setting unit 130. The blowers 11, 12, 13, 14 and 15 are 65
FIG.9 shows a second embodiment of the embodiments ofcontrolled via the controller 150 according to the deviation,and the inject rate of bubbles from the gas outlets 21, 22, 23. the present invention. The second embodiment will beUS 9,376,167 B2
51
described on difference from the first embodiment. The otherelements adopt configurations analogous to those in the first
embodiment.

52of the gas outlets 21, 22, 23, 24 and 25 is odd, the center one(gas outlet 23) can be arranged on the planar center line CL.
This can realize one spot injecting of bubbles while holding
the ability of the vessel to hold a straight line.
Since the distribution component 71, which has the trian
gular profile and disperses the blown air, is arranged imme
diately below the connection part of the air supply pipe 16, thedistribution component 71 laterally disperses and uni

In FIG.9, the gas outlets 21, 22, 23, 24 and 25 are arrangedon the bottom 3 of the vessel 1, as shown in the figure. Morespecifically, a planar portion of the fore of the bottom3 of thevessel is configured to be a so-called boat shape as indicatedby broken lines. The gas outlets 21, 22, 23, 24 and 25 arearranged symmetrically with respect to the planar center line formizes air.
CL of the hull 4 along the fore shape of the bottom 3 of the 10 The apertures of the perforated plates 72 and 73 used forvessel.
the gas outlets 21, 22, 23, 24 and 25 are configured to be round
This allows the bubbles injected from the gas outlets 21, 22. apertures. This eliminates edges. In a case of using stainless
23, 24 and 25 to cover the entire surface of the bottom3 of thematerial, concentration of stress cannot easily occur during
vessel most effectively. Further, since the bubbles are along pressing, thereby alleviating development of stress corrosion
the fore shape, the bubbles can be injected from a spot such 15 even in use in seawater.
The Roots-type blower is used as the gas Supply or charged
that the bubbles can be retained longest also for the stern. This
allows reduction in frictional resistance to be further
air means. This type is different from the piston-type, even
improved, and enables the fore having a large frictional resis though both types are the same positive-displacement type.
tance to be effectively covered. In this case, since the number The Roots-type blower pressurizes air substantially continu
ofgas outlets 21, 22, 23, 24 and 25 is odd, the centergas outlet ously and thereby reduces pulsing, and can eliminate a tank23 can be arranged at the distal end of the so-called boat and the like for smoothing pressure. Moreover, the rotation isshape. This enables the bubbles to be injected from the one Smooth and vibration and noise are reduced. Accordingly,
gas outlet 23 while maintaining the ability of the vessel 1 to even with the arrangement of the blowers 11, 12, 13, 14 andhold a straight line, and allows the bottom3 of the vessel to be 15 on the deck 2, occurrence of resonance can be prevented in
25 the cabins therebelow.
covered with the bubbles most effectively.
As described above, these embodiments adopt the configu
The number of gas outlets 21, 22, 23, 24 and 25 is odd. Thisration where the plurality of gas outlets 21, 22, 23, 24 and 25 enables the centergas outlet 23 to be arranged at the distalend
and the plurality of blowers 11, 12, 13, 14 and 15 blowing air of the so-called boat shape, enables the bubbles to be injectedto the plurality of gas outlets 21, 22, 23, 24 and 25 are from the one gas outlet 23 while maintaining the ability of thearranged at the bottom 3 of the vessel, and the blowers are 30 vessel 1 to hold a straight line, and enables the bottom3 of thedriven by respective inverter-type motors 60 as the drive vessel to be covered with bubbles most effectively.
The inverters of the motors 60 and the valves 161,162,163,
device. Further, as the navigational condition detectionmeans for detecting the navigational condition of the vessel 1,
164 and 165 controlled by the controller 150 are provided as
the relative velocity sensors 55, 56 and 57, the draft sensor the gas adjustment means for controlling injecting gas from
111 and the inclination sensor 112 are provided at the navi 35 the gas outlets 21, 22, 23, 24 and 25. This enables the inject
gational condition detector A, and the shear force sensors 51, conditions, such as starting/stopping injecting bubbles and52, 53, 54 and 55 are provided at the navigational condition the inject rate of bubbles, to be arbitrarily controlled, thereby
detector B115. The control device controls the motors 60 ofallowing the net frictional resistance to be effectively
the respective blowers according to detection results from the reduced.
40
navigational condition detectors A110 and B115.
The relative velocity sensors 55.56 and 57 adopt the ultra
According to this configuration, the rise of the bubbles is Sonic system. This allows use in the water, and enabling
suppressed by the bottom3 of the vessel itself, and the bubble influences of waves and currents to be reduced.
retention effect can be maintained, thereby allowing the fricThe relative velocity sensors 55, 56 and 57 detect relative
tional resistance to be effectively reduced by a small amount Velocities with seawater. The prescribed statistical processingof bubbles. Further, influences of waves are alleviated at the 45 is applied thereto. The representative value is transmitted togas outlets 21, 22, 23, 24 and 25 arranged at the bottom 3 of the comparator 140, and used. Accordingly, the detection
the vessel, in comparison with a case of arrangement at the errors are reduced, thereby allowing accurate control.
sides of the vessel. This enables bubbles to be stably injected.
The draft sensor used for the bubble injecting control canalso be used for estimating the amount of freight in the vessel
As a result, frictional resistance reduction effect at the hull
can be exerted. Moreover, one blower is arranged for one gas 50 1 and adjusting the draft of the vessel 1.
outlet correspondingly. This facilitates the bubble injecting
The inclination sensor 112 can be shared for detecting thecontrol with respect to the separate gas outlets 21, 22, 23, 24 inclination of the hull 4 and adjusting the ballast water forand 25, and can alleviate the problem of variation in inject rate maintaining balance, in addition to use for the bubble injectof bubbles owing to waves particularly in a case of using in the ing control.
ocean. Further, the gas blowing condition can be controlled 55 The shear force sensors 51, 52,53,54 and 55 preliminarily
according to the detection results from the navigational con measure the relationship between the relative velocity and thedition detectors A110 and B115. This allows the injecting of shear force in seawater without mixture of bubbles, and the
bubbles to be finely controlled in a variable manner, respon relationship between the amount of bubble mixture, the rela
sive to navigational conditions, in comparison with a case of tive velocity and the shear force in seawater with mixture of
injecting gas contently. Accordingly, reduction in frictional 60 bubbles. Accordingly, the condition of bubble mixture effec
resistance that further improves the net reduction effect can tively acting on the bottom 3 of the vessel can be estimated.
be expected.
Further, the frictional resistance acting on the bottom 3 of the
The arrangement of the gas outlets 21, 22, 23, 24 and 25 vessel and the entire hull can be estimated from the shear
Substantially in a line allows the configuration to be simpli force.
fied, and can also facilitate the arrangement of blowers 11, 12, 65 The vessel conditions determination unit 100 is provided in
13, 14 and 15 and the air supply pipe 16, 17, 18, 19 and 20, addition to the navigational condition detectors A110 andwhich are provided accordingly. Moreover, since the number B115. The control of starting/stopping injecting gas from theUS 9,376,167 B2
53
gas outlets 21, 22, 23, 24 and 25 is performed according tothese detection/determination conditions.
In a case where the reduction effect in frictional resistanceby injecting bubbles cannot be expected according to thisconfiguration, the injecting bubbles are stopped. In a casewhere the reduction effect can be expected, the bubbles are
injected. This can prevent power from being used in vain, and54
Accordingly, even with the arrangement of blowers 10, 11,
12, 13 and 14 on the deck 2, resonance cannot easily occur inthe cabins therebelow.

The air taken by the blowers 10, 11, 12, 13 and 14 ispressurized, passes through the air supply pipe 16, 17, 18, 19
and 20 having bent portions, and guided to gas outlets (hereinafter, also referred to as “air nozzle'') 21, 22, 23, 24 and 25
allows the frictional resistance reduction effect to be effec
arranged in the proximity of the bottom3 of the vessel. In thisembodiment, the gas outlets 21, 22, 23, 24 and 25 aretively exerted.
A difference according to threshold is provided in the rep 10 arranged substantially symmetrically with respect to the pla
resentative value, which has been subjected to the statistical nar center line CL of the hull 4 substantially in a line, on theprocessing of relative velocities. When the vessel 1 is fore surface of the bottom 3 of the vessel. The gas outlets 21,
stopped, the injecting of bubbles is stopped earlier, thereby 22, 23, 24 and 25 are arranged on the bottom 3 of the vessel iseffectively utilizing the residual bubbles. This can realizes the for the sake of causing the injected bubbles to be retained
injecting of bubbles in consideration of the substantial fric 15 longer at the bottom 3 of the vessel, and alleviating variationin pressure owing to waves. The arrangement at the fore of thetional resistance reduction effect.
The waterline level is adjusted on the basis of the condition bottom 3 of the vessel is for the sake of causing the injected
setting instruction 132. This allows distinction with the con bubbles to be retained over the entire bottom3 of the vessel as
dition setting instruction 131 for reducing the frictional resis much as possible.
The arrangement of the gas outlets 21, 22, 23, 24 and 25
tance, and enables the waterline level to be adjusted using theSubstantially in a line is for the sake of simplifying the consame gas outlets 21, 22, 23, 24 and 25 and the blowers 11, 12.
figuration, and also facilitating the arraignment of the blowers
13, 14 and 15 for reducing the frictional resistance.
Further, according to the present application, the bubble 10, 11, 12, 13 and 14 and the air supply pipes 16, 17, 18, 19
size is made large when the relative Velocity is fast, and the and 20, which are provided correspondingly. In this example
bubble size is made smaller when the relative velocity is slow. 25 the number of the air nozzles 21, 22, 23, 24 and 25 is five,
This can exert the advantageous effect specific to the present which is an odd number. Accordingly, the center one (airapplication that the buoyancy is increased when the bubble nozzle 23) may be disposed on the planar center line CL. Thissize become larger, and the bubbles adhere well to the bottom can realize one spot injecting of bubbles while maintaining
the ability of the vessel 1 to hold a straight line. In this case,of the vessel even with the fast relative velocity.
When the waterline becomes deep, the bubble size 30 the air nozzles 21, 22, 23, 24 and 25 can adopt a configuration
where the nozzles are arranged substantially symmetrically
becomes small and the frictional resistance reduction effect isreduced. However, according to the present application, the with respect to the planarcenterline CLofthehull 4 along theamount of bubbles is controlled according to the draft. There planar shape of the fore of the bottom 3 of the vessel.
The end plates 5, 5", 6, 6, 7 and 7" for guiding bubbles
fore, even in this case, this can exert the advantageous effectspecific to the present application that can perform comple 35 injected from the air nozzles 21, 22, 23, 24 and 25 such thatthe bubbles do not escape are arranged also symmetricallyment by increasing the amount of bubbles.
with respect to the planar center line CL of the hull 4 on the
Third Embodimentbottom3 of the vessel. The end plates 6 and 6' and 7 and 7" areillustrated so as to be in the same dimensions in this figure.
FIG. 10 is an embodiment where a bubble retention device 40 However, the end plates 7 and 7" may have smaller dimen
according to an embodiment of the present invention is sions than those of the end plates 6 and 6'. The number of end
applied to a vessel used in the ocean. FIG. 10 (a) shows a side plates is not limited to that represented in this figure. Inview of the vessel. FIG.10(b) shows a top view thereof. FIG. addition thereto, the shear force sensors 50, 51, 52,53 and 54
10(c) shows a bottom view. A part of a principal configuration as shear force detectors for detecting shear forces owing to
45 seawater and bubbles acting on the hull 4 are arranged on theis represented in an exposed manner.
The blowers 10, 11, 12, 13 and 14 as the gas supply or bottom 3 of the vessel.
charged air means are arranged in a line on the deck 2 of the
The relative velocity sensors 55 and 56 as the relative
vessel 1. These blowers 10, 11, 12, 13 and 14 are arranged in velocity detectors are arranged aft. Other relative velocity
a casing on the deck 2 in order to avoid splash of seawater sensors 57 are arranged on the sides 8 of the vessel. These
broken at the bow. For the sake of avoiding a splash as much 50 relative velocity sensors 55 and 56 are arranged apart from theas possible, the air as gas is taken from a direction opposite to air nozzles 21, 22, 23, 24 and 25. On the other hand, therelative velocity sensors 57 are arranged on spots without any
the traveling direction of the hull.
The blowers 10, 11, 12, 13 and 14 are Roots-type positive influence of bubbles on the sides 8 of the vessel, even if thedisplacement blowers, and adopt a structure (not shown) spot is near the nozzles. In particular, the relative Velocity
where an inverter-type motor 60 (not shown) as the drive 55 sensors 57 are arranged at lower spots without receiving theinfluence owing to waves, even though the spots are on thedevice drives two rotors in the blower via a belt, the air taken
between the blower interior wall and the rotors is compressed sides 8 of the vessel. These relative velocity sensors 55, 56
as the rotors rotate, and Supplied (not shown). Since the and 57 adopt ultrasonic systems. This allows use in the water,
blowers 10, 11, 12, 13 and 14 are the positive-displacement and reduces the influence owing to waves and currents.
type, the blowers are capable of Supplying stably a predeter 60 The video cameras 58 and 59 for monitoring conditions ofmined rate of air even with previous variation in pressure. injected bubbles are arranged at fore and aft parts of the
Although the Roots-type blower is the same positive-dis bottom 3 of the vessel. Images taken by these video cameras
placement type, the Roots-type blower is different from the 58 and 59 are monitored by a person and utilized for analyz
piston type in that the Roots-type blower pressurizes air sub ing the inject condition of bubbles.
stantially continuously and thereby reduces pulsing, and can 65 FIG. 11 is a sectional view of the hull 4 according to one
eliminate a tank and the like for Smoothing pressure. Further, embodiment of the present invention taken along line X-X (inthe rotation is Smooth and vibration and noise are reduced.
FIG. 10). As shown in this figure, the end plates 5 and 5' andUS 9,376,167 B2
56
3 of the vessel, a component pertaining to the streamlined
shape may be attached to the end plate 5. It is preferable thatthe aft part of the end plate also have a streamlined shape (notthe vessel and the sides 8 of the vessel in order to facilitate
shown).
stability on sailing. This can Suppress rolling and turning over 5 FIG. 15 is a sectional view of the hull 4 according to still
onto the side of the vessel, against natural phenomena, Such as another embodiment of the present invention taken along line
waves and currents, and a collision object. The end plates 5 X-X (of FIG. 10). This figure shows a mode where a concave
and 5' according to the present invention can be arranged portion is formed at the bottom 3 of the vessel. As shown inseparately from the bilge keels 101 and 101'. The arrange this figure, there are adapted a configuration where the end
ment spots are preferably inside of the bilge keels 101 and 10 parts 5c and5care left instead of the end plates 5 and 5' shown101' with respect to the planar center line CL.
in FIG. 11 and other parts are cut out, or a configuration where
On the other hand, the end plates 5 and 5' may be used for a configurational member pertaining to the concave portion
stabilizing the vessel. In this case, the performances pertain having the end parts 5c and 5c' is arranged, or a configuration
ing to stabilization of the bilge keels 101 and 101" can be where the end parts 5c and 5c' are attached to the alreadymodified to an extent where the end plates 5 and 5' take charge 15 provided bottom3 of the vessel, or a configuration where theof the stabilizing function. In this case, the design is prefer bottom 3 of the vessel itself has the concave portion. The
ably performed in consideration of structures, dimensions, forces of the end parts 5c and 5c may be streamlined shapes
arrangement spots and the like of the end plates 5 and 5' and as shown in FIG. 14. These end parts are different from thethe bilge keels 101 and 101", so as not to impede sailing of the end parts 5 and 5' pertaining to FIG. 11 only in that the shapevessel. The original purpose pertaining to the end plates 5 and is different. Accordingly, further detailed description is omit
5'' is to cause the bubbles to flow while retaining the bubbles ted. The end parts 5c and 5c and the concave portion sandat the bottom 3 of the vessel. Accordingly, designs of the end wiched between these end parts enable bubbles to flow whileplates 5 and 5' and the bilge keels 101 and 101' are to be being retained at the bottom of the vessel.
FIG. 16 is a sectional view of the hull 4 according to yet
adopted in consideration of this.
FIG. 12 is a sectional view of the hull 4 according to 25 another embodiment of the present invention taken along line
another embodiment of the present invention taken along line X-X (of FIG. 10). This figure shows a mode where a concave
X-X (in FIG. 10). This figure shows a mode where the profile portion is formed at the bottom 3 of the vessel. As shown inof the end plate is configured as a Substantially triangle. As this figure, there are adapted a configuration where the end
shown in this figure, the end plates 5a and 5a' have a substan parts 5d and 5d are left instead of the end plates 5 and 5
tially triangular shape whose base is the bottom 3 of the 30 shown in FIG. 11 and other parts are cut out, or a configura
vessel. These end plates are different from the end plates 5 and tion where a configurational member pertaining to the con
5' pertaining to FIG. 11 only in that the shapes are different. cave portion having the end parts 5d and 5d is arranged, or a
Accordingly, the detailed description thereof is omitted.
configuration where the end parts 5d and 5d are attached toHere, in comparison between contact areas with water in the already provided bottom 3 of the vessel. These end parts
cases of using this substantially triangular profile and the end 35 are different from the end parts 5c and 5c pertaining to FIG.
plate 5 or 5' of the flat plate, the sum of two sides of the 15 in the shapes at a part of the quadratic curve. The forces oftriangle is longer than one side. The adoption of the Substan the end parts 5d and 5d may be streamlined shapes as shown
tially triangle shape narrows the contact area with water, and in FIG. 14. These end parts are different from the end parts 5
allows the frictional resistance by arrangement of the end and 5' pertaining to FIG. 11 only in that the shape is different.
plates to be reduced. These end plates 5a and 5a' having a 40 Accordingly, the detailed description is omitted. The end
Substantially triangular shape allow increase in frictional parts 5d and 5d and the concave portion sandwiched between
resistance of the end plates to be Suppressed.
these end parts enable bubbles to flow while being retained at
FIG. 13 is a sectional view of the hull 4 according to still the bottom of the vessel.
Next, operation and a method ofusing the bubble retention
another embodiment of the present invention taken along line
X-X (FIG. 10). This figure shows a mode where the profile of 45 device according to one embodiment of the present invention
the end plate is quadratic function curve or the like. As shown will be described using the conceptual view.
FIG. 17 is a conceptual view showing a state of retaining ofin this figure, the end plates 5b and 5b' have a shape to be a
curve. Such as a quadratic function curve, whose base is the bubbles in a case where end plates 5 and 5' according to an
bottom 3 of the vessel. These end plates 5b and 5b' are embodiment of the present invention are arranged. This figure
different from the end plates 5 and 5 pertaining to FIG. 11 50 shows a state of retaining bubbles when the vessel is inclined.
only in that the shapes are different. Accordingly, the detailed In this case, in the sectional view taken along line X-X in FIG.
description thereof is omitted. These end plates. 5a and 5a'
10, the inclination of the vessel causes a differential pressure
having the shape to be a curve. Such as a quadratic function between opposite ends of the bottom 3 of the vessel, and thecurve, allows increase infrictional resistance of the end plates bubbles moves to a low pressure part. This diffuses the
55 bubbles out of the extent of the bottom3 of the vessel, thereby
to be suppressed.
FIG. 14 is an enlarged view of a broken line Y part of FIG. reducing the frictional reduction effect by the bubbles. On the
11 according to yet another embodiment of the present inven other hand, in the present application, the end plates 5 and 5
tion. This figure shows a mode where the fore of the end plate are arranged at the opposite ends of the bottom3 of the vessel,
is a streamlined shape. As shown in this figure, the end plate thereby suppressing the bubble diffusion. More specifically,
5 is preferably formed as a streamlined shape at its inner side 60 the bubbles moves from a high pressure part to a low pressure
with reference to the planar center line CL. It is necessary to part, and it is impossible to move from the low pressure part
perform the design in consideration that the end plate does not to the high pressure part. Accordingly, to move to the low
impede sailing of the vessel. More specifically, the distal end pressure part, the bubbles should detour around a barrierof the end plate 5 preferably has a shape similar to a shape pertaining to the end plate 5. Thus, it is necessary to move towhere the angle of the surface is finely changed as with the 65 the high pressure part. Therefore, according to the above
distal end of a Sword for facilitating cut an object. In cases principle, the bubbles can be retained at the bottom 3 of thewhere the end plate 5 has already been provided on the bottom vessel. Likewise, in a case of reversed inclination. Even with55
the bilge keels 101 and 101" are disposed. Typically, forexample, the vessel is equipped with bilge keels arranged atconnecting portions (bilge portion) between the bottom 3 ofUS 9,376,167 B2
57
58
out the inclination of an extent shown in this figure, the a mound that has a wing profile in a sectional view when the
bubbles detect a slight differential pressure according to a vessel is sailing, according to still another embodiment of theslight rolling and the like in sailing, and the bubbles move to present invention. In this figure, water flows in the opposite
a low pressure part in an analogous manner. However, the end direction to the traveling direction of the vessel. Likewise, theplate 5 suppresses the diffusion owing to movement of 5 bubbles also flow in the direction of the flowing water. On the
bubbles, and the bubbles flow to the end of the end plate 5 other hand, as the bubbles flow downstream, the bubbles
while being retained. This allows the bubbles to be retained diffuse in the water. Accordingly, the frictional reduction
against the inclination of the vessel occurring owing to dis effect by the bubble is reduced. However, a wing profile
turbance Such as waves and flows and turning, and can effec mound 102 is provided on the bottom 3 of the vessel. This
10 attaches the bubbles to the bottom 3 of the vessel again, andtively facilitate reduction in frictional resistance.
FIG. 18 is a conceptual view showing a state where bubbles improving the frictional reduction effect. More specifically,
flow when a vessel is sailing in a case of arrangement per the bubbles flow along the shape of the wing profile moundtaining to the end plates 5 and 5' according to an embodiment 102. In order to cause the bubbles to flow along the shape ofof the present invention whose fore and aft parts have stream the wing profile mound 102, the surface shape of the wing
lined shapes. In this figure, the fore parts of the end plates 5 15 profile mound 102 is required to be a shape having a Smoothly
and 5' have symmetrical shapes with respect to the center line. curved profile in a sectional view. In a case where the starting
Accordingly, end plates 5 and 5' can avoid becoming a resis end of wing profile mound 102 has an angle that is nottance impeding sailing of the vessel as much as possible. The smooth, there is a possibility that the surface of the wing
aft parts of the end plates 5 and 5' have a smooth curve or profile mound 102 becomes a barrier and the bubbles diffuse
inclination based on the center line from a deep aft part at a collision. In a case where the terminating end of the wingterminating a shallow aft part to form a streamlined shape. profile mound 102 has an angle that is not smooth, the bubbles
The bubbles are not released from the retained state suddenly Suddenly moves to a low pressure part pertaining to the bot
attermination point pertaining to the aft parts of the end plates tom 3 of the vessel because of a differential pressure caused
5 and 5' as a boundary. Instead, the dimensions of the end by an inclination between the terminating end and the bottom
plates 5 and 5' become smaller at the starting point of the 25 3 of the vessel. This shape makes a part where bubbles do not
Smooth curve or inclination pertaining to the aft parts as a accompanies the bottom 3 of the vessel. Accordingly, use ofboundary. This shape Smoothly releases the state of retaining the differential pressure caused at the wing profile mound 102
bubbles. Accordingly, the bubbles gradually diffuse into the having Such a shape can Suppress the bubble diffusion andwater. Further, a configuration where the aft parts open causes improve the frictional reduction effect.
the bubbles, which have flowed while sufficiently covering 30 FIG. 21 is a sectional view conceptually showing a state of
the bottom of the vessel, to flow outwardly. This eliminates retaining bubbles at a vessel whose bottom 3 has a configu
convolvement of the bubbles into the propeller (not shown) ration having a gentle step profile toward the stern in a sec
provided at the stern, and can thereby prevent the propulsion tional view when the vessel is sailing, according to yetfrom dropping.
another embodiment of the present invention. In this figure,
35 analogous to the above, water flows in the opposite direction
Fourth Embodiment
to the traveling direction of the vessel. Likewise, the bubbles
flow in the flowing water direction. On the other hand, as the
FIG. 19 is a sectional view conceptually showing a state of bubbles flow downstream, the bubbles diffuse in the water.
retaining bubbles when a vessel whose bottom 3 has a trian This reduces the frictional reduction effect by the bubbles.
gular uneven profile in a sectional view is sailing, according 40 However, the bottom3 of the vessel has the gentle step profile
to still another embodiment of the present invention. In this toward the stern in a sectional view. This attaches the bubbles
figure, in a case where the section of the bottom3 of the vessel to the bottom 3 of the vessel again, and allows the frictional
is an uneven profile pertaining to triangles, inclinations are reduction effect to be improved. More specifically, fluid force
formed by first and second triangles adjacent to each other effect because of the shapes of the first and second differences
whose bases are the bottom 3 of the vessel pertaining to the 45 of steps allows the bubble diffusion to be suppressed, anduneven profile. Differential pressures generated by the incli enables the frictional reduction effect to be maintained.
nations move the bubbles to a low pressure part. The bubbles Analogous to the above, it is necessary that the terminating
surrounded by one triangular profile flow in the aft direction end of the difference of steps have a gently curved shape.
along the longitudinal direction with a low resistance, Without this shape, the bubbles suddenly move to a low
because crossing over the vertices of the triangles faces a 50 pressure part pertaining to the bottom 3 of the vessel, by aresistance. This suppresses movement and diffusion of differential pressure caused by an inclination between the
bubbles even by the differential pressure generated by the terminating end pertaining to the first difference of steps andinclination of the hull on sailing of the vessel or a slight the starting end of the second difference of steps. This forms
differential pressure generated by slight rolling. Accordingly, a part where the bubbles do not attach to the difference ofthe bubbles flow while being retained at the bottom 3 of the 55 steps or the bottom 3 of the vessel is formed.
vessel. The height dimension of the triangle whose base is theFifth Embodimentbottom 3 of the vessel is preferably equal to or less than 10
mm with reference to the bottom3 of the vessel. The basic of

FIG.22 is a sectional view for illustrating a configuration
this concept is to that the triangle is formed to have a heightequal to or less than a height sufficiently covered with the 60 of a gas-liquid separator 200 in a bubble retention device
bubbles. More specifically, the height dimension of the tri according to a fifth embodiment of the present invention. As
angle whose base is the bottom3 of the vessel is not limited to shown in this figure, the gas-liquid separator 200 includes athat equal to or less than 10 mm with reference to the bottom main body 201, a bubble separation facilitating filter 202, a
3 of the vessel. Instead, the height may be about that where the gas transfer pipe 203, a gas release port 204, a liquid transfer
65 section 205, and valves 206a, 206b and 206c. The principle ofbottom is sufficiently covered with bubbles.
FIG. 20 is a sectional view conceptually showing a state of the water displacement is applied to the gas-liquid separator
retaining bubbles at a vessel having a configuration including 200. FIGS. 23 and 24 are conceptual views showing a method

US 9,376,167 B2
59
of using the gas-liquid separator 200 in the bubble retention
device according to second embodiment of the present inven

60
drawing, the bubbles diffuse in the water again, thereby gen
tly increasing the frictional force.
tion.
Operation and a methodofusing of the gas-liquid separator
The main body 201 includes a moisture intake B, which is 200 pertaining to the bubble retention device according to one
always open. The main body 201 internally includes a func embodiment of the present invention will hereinafter betion of separating liquid and air from each other via the bubble described with reference to FIGS. 22, 23 and 24. The gas
separation facilitating filter 202. The bubble separation facili liquid separator 200 pertaining to FIG. 22 is that the gas
tating filter 202 has a conical shape Surrounding a hollow liquid separator pertaining to FIGS. 23 and 24 is viewed
cylinder having a moisture intake. The filter is formed into a sectionally from the rear. Accordingly, FIGS. 23 and 24 andconical shape. The gas transfer pipe 203 has a configuration 10 FIG.22 are laterally inverted.
where one opening is disposed inside of the main body 201,
As shown in FIG. 22, the moisture intake Balways opens.
and the other opening is outside of the main body 201. The Accordingly, the configuration is adopted where moisture
blower 208 has a function of drawing air from the opening comes inside of the main body 201 pertaining to the gas
pertaining to the outside via the valve 206a. The blower 208 liquid separator 200 via the moisture intake B. Here, water inis preferably has a configuration capable of transferring air 15 the main body 201 can be retrieved by drawing of the pumpeven if water is mixed therein. A gas release port 204 is 207. In retrieval, the bubble separation facilitating filter 202
arranged on the top of the main body 201. A configuration separates gas included in water and liquid from each other.
capable of releasing unnecessary air to atmosphere via the Accordingly, only liquid can be retrieved via the liquid transvalve 206b is adopted. On the other hand, the liquid transfer fer section 205. The retrieved moisture can be used for cool
section 205 is provided inside of the main body 201, in a ing water for the engine of the vessel. Presence and absence ofmanner where the bubble separation facilitating filter 202 is a drawing water can be operated by opening and closing theboundary, and a configuration capable of drawing water by a valve 206c. The pump 207 may always be driven. On the otherpump 207 via the valve 206C is adopted.
hand, the gas separated by the bubble separation facilitating
Next, FIG. 25 is a diagram showing a situation pertaining filter 202 can be retrieved by drawing of blower 208 via gas
to use of the gas-liquid separator 200 in the bubble retention 25 transfer pipe 203. Presence and absence of drawing gas can be
device according to the fifth embodiment of the present inven operated by opening and closing the valve 206c. The blower
tion. In this figure, (a) (hereinafter, also referred to as “(a)) is 208 may always be driven.
a conceptual view showing a frictional reduction effect when
Therefore, as shown in FIG. 23, the air drawn by the blower
blowers 10, 11, 12, 13 and 14 according to an embodiment of 208 is released to atmosphere, and the gas in the main bodythe present invention blow air. In this figure, the abscissa axis 30 201 is released to atmosphere via the valve 206b. Accord
represents a distance, and the ordinate axis represents what is ingly, the gas-liquid separator 200 can attract the gas to theconverted from the frictional reduction effect into numericproximity of the bottom 3 of the vessel again. As shown invalue within an extent from 0.0 to 1.0. 1.0 represents the FIG. 24, the gas drawn by the blower 208 can be injected
maximum value of the frictional force. 0.0 represents the again via the retrieved air nozzle C, thereby also allowing theminimum value of the frictional force (without friction). Fur 35 frictional reduction effect to be amplified.
ther, in the figure, (b) (hereinafter, also referred to as “(b)) is
Sixth Embodimenta diagram showing a bubble diffusion condition in the water
after blowing by the blowers 10, 11, 12, 13 and 14 according
to an embodiment of the present invention. In this figure, theFIG. 26 shows an example where the bubble convolvement
direction of the water flow is a direction from left to right. (a) 40 prevention device for a vessel according to one embodimentand (b) have a relationship that both are correspond to each of the present invention is applied to a vessel used in theother. Accordingly, description will hereinafter be made ocean. FIG. 26 (a) is a side view of the vessel. FIG. 26 (b) isusing both figures and FIG. 22 as necessary.
a top view thereof. FIG. 26 (c) is a bottom view. A part of aFirst, as shown in (b), airinjected via the air nozzle 20 drifts principal configuration is represented in an exposed manner.
around the bottom 3 of the vessel. Accordingly, referring to 45 The blowers 10, 11, 12, 13 and 14, as the gas supply or(a), a state almost without friction because of the frictional charged air means, are arranged on the deck 2 of the vessel 1.
reduction effect can be confirmed. However, referring to (b). The taken air is separately pressurized, passes through the air
once the bubbles are injected, the bubbles move along with supply pipes 3016, 3017, 3018, 3019 and 3020 having bent
the water flow. Accordingly, the bubbles diffuse in the water, portions, and guided to the air nozzles 21, 22, 23, 24 and 25,
and leave the proximity of the bottom 3 of the vessel. There 50 which are gas outlets arranged in the proximity of the bottom
fore, referring to (a), the frictional reduction effect is sud 3 of the vessel. In this embodiment, the air nozzles 21, 22, 23,
denly reduced (the frictional force is suddenly increased). 24 and 25 are arranged at the fore of the bottom3 of the vessel,
Subsequently, the frictional force increases at a certain rate symmetrically with respect to the planar center line CL of the(the numeric value approaches 1.0 from 0.0). This can also be hull 4, substantially in a line. The arrangement of the air
considered as a phenomenon that occurs because moisture 55 nozzles 21, 22, 23, 24 and 25 at the bottom 3 of the vessel is
intrudes between the bubbles and the bottom 3 of the vessel.
for the sake of prolonging the retention of the injected bubbles
Therefore, referring to (b), the moisture intake B is arranged over the entire bottom3 of the vessel and alleviating variation
for drawing the incoming moisture before the bubbles diffuse in pressure owing to waves and the like. The arrangement at(when the bubbles leave the bottom3 of the vessel by about 5 the fore of the bottom3 of the vessel is for the sake of causing
to 7 mm) on the bottom 3 of the vessel in the astern direction 60 the injected bubbles to be retained over the entire bottom3 of(downstream direction of the waterflow) with reference to the the vessel as much as possible.
The blowers 10, 11, 12, 13 and 14 are Roots-type positive
air nozzle 20. The gas-liquid separator 200 shown in FIG.22
draws a small amount of moisture via the moisture intake B.
displacement blowers. Since the blowers are the positive
This attracts the bubbles to the proximity of the bottom 3 of displacement type, the blowers are capable of stably Supply
the vessel again. Accordingly, referring to (a), the frictional 65 ing a predetermined rate of air even with previous variation inforce is Suddenly decreased immediate after drawing mois pressure. The Roots-type blower is capable of pressurizing air
ture. This recovers the frictional reduction effect. After the
Substantially continuously. Accordingly, pulsing is reduced,

US 9,376,167 B2
61

62

the rotation is Smooth and vibration and noise are also

further uniformization of the air in the lateral direction, the air

reduced. Even with the arrangement of blowers 11, 12, 13, 14
and 15 on the deck 2, resonance cannot easily occur in theis uniformized also in the vertical direction, thereby enabling
the air to be injected from a inject port 76 on a front surface.
FIG. 27 is a control block diagram of this embodiment.

cabins therebelow.

The end plates 5,5", 6, 6', 7 and 7", which guide the bubbles
injected from the air nozzles 21, 22, 23, 24 and 25 so as not toescape, are arranged on the bottom 3 of the vessel symmetri
cally with respect to the planar center line CL of the hull 4. In

The vessel conditions determination unit 100 includes a

GPS 101 detecting the location of the vessel 1, a fuel mea
Surement unit 102 measuring fuel consumption of engines ofthe vessel 1, and an engine operation detector 103 detecting
operational conditions of the engines of the vessel 1. The
addition thereto, the shear force sensors 50,51,52,53 and 54,
which detect shear forces owing to seawater and bubbles 10 vessel conditions determination unit 100 specifically deter
acting on the hull 4 are arranged aft on the bottom 3 of the mines the present conditions of the vessel 1, and determines
vessel.
the present conditions that vary in a small degree on sailing or
The relative velocity sensors 55 and 56 are arranged aft. vary gradually.
The GPS 101 is used for determining which position orAnother relative velocity sensor 57 is arranged on the sides 8of the vessel. These relative velocity sensors 55 and 56 are 15 location on the map the bubble is injected or stopped. The fuelarranged apart from the air nozzles 21, 22, 23, 24 and 25. On measurement unit 102 is used for measuring how much thethe other hand, the relative velocity sensor 57 is arranged on engine consumes fuel in a prescribed time period and, whena spot without any influence of bubbles on the sides 8 of the the fuel consumption efficiency falls below a prescribed effi
vessel, even if the spot is near the nozzles. In particular the ciency, the injecting bubbles is stopped. The engine operation
relative velocity sensor 57 is arranged on a lower part of the detector 103 detects various operating conditions including
starting/stopping the engine of the vessel 1, and is used forsides 8 of the vessel without receiving influences of waves.
The video cameras 58 and 59 for monitoring conditions of acquiring information on stopping injecting bubbles when theinjected bubbles are arranged at fore and aft parts of the operation of the engine is stopped, and starting injecting
bottom 3 of the vessel, respectively. Images taken by these bubbles a prescribed time period after starting the operation.
video cameras 58 and 59 are monitored by a person and 25 The engine operation detector 103 is also used for detecting
utilized for analyzing the inject condition of bubbles.
the numbers of revolutions of the engines, and changes theHere, a screw type propeller 80 is provided at the stern 9 of number of working air nozzles and/or the inject rate of
the hull 4 of the vessel 1. A rudder 81 is arranged aft thereof. bubbles.
Inside of the hull 4, the thrust torque gage 83 detecting the
The navigational condition detector A110 includes thethrust force and torque is attached to the drive shaft 82 of the 30 relative velocity sensors 55, 56 and 57, the draft sensor 111
propeller 80. A vibration sensor 84 detecting vibration is detecting the waterline level of the hull, and the inclination
attached in the proximity of the drive shaft 82. The thrust sensor 112 detecting the lateral inclination with respect to thetorque gage 83 may be a straingage arranged on the Surface of traveling direction of the hull, which is so-called rolling.
the drive shaft 82 of the propeller 80. Since the drive shaft 82 Separate therefrom, the shear force sensors 51, 52,53,54 androtates, the thrust torque gage 83 picks up a signal wirelessly 35 55 configure the navigational condition detector B115. Thesesuch that wires are not tangled. The vibration sensor 84 is navigational condition detectors A and B detect physicalarranged on the bearing or the like in the proximity of the quantities that relatively easily vary along with sailing of thedrive shaft 82, and picks up vibration electrically.
vessel 1, or are controlled for the sake of changing.
V-shaped mound 190, which has a V-shape laterally
The oceanographic condition determination unit 120
spreading centered at the planar center line CL of the hull 4, 40 includes the wave sensor 121, the wind sensor 122 and theis arranged on the bottom3 of the vessel, as a protuberance of current sensor 123. The wave sensor 121 detects the wave
the bubble convolvement prevention structure. The mound is height, direction, period and the like of a wave. The wind
formed so as to include a wrapping portion 191 spreading sensor 122 detects the wind velocity and direction of a wind.
The current sensor 123 detects the current velocity, direction,around up to the sides 8 of the vessel.
The air nozzles will be described using the figure of the first 45 height and the like of a current. In addition thereto, theembodiment. FIG.3 is a perspective view conceptually show oceanographic condition determination unit considers infor
ing the detailed structures of the air nozzles 21, 22, 23, 24 and mation on waves, winds, currents and the like including infor
25. For the sake of simplicity of description, FIG. 3 shows a mation on a general weather, and is used for determining thattypical example of the plurality of air Supply pipes and the air the injecting of bubbles is stopped when the oceanographic
nozzles. The air blown from the blower 14 via the air supply 50 condition is stormy, and bubbles are generated when thepipe 16 is bent at right angle at a chamber 70 of the air nozzle condition is recovered.
The convolvement detector 180 includes an axial thrust
21 connected to the air supply pipe 16. A distribution com
ponent 71 having triangular profile for dispersing the blown torque gage 83 provided on the drive shaft 82 of the propeller
air is arranged immediately below the connection part of the 80, and the vibration sensor 84 arranged in the proximity of
air supply pipe 16. A configuration is adopted according to 55 the drive shaft 83. These gage and sensors detect that bubbles
which the air is bent at right angle at this part and dispersed are convolved into the propeller 80, and at least used forlaterally by the distribution component 71. This uniformizes changing the operating conditions and the inject conditions of
the lateral distribution of the air with respect to the perforated the blowers 10, 11, 12, 13 and 14 and the air nozzles 21, 22,
plates 72 and 73.
23, 24 and 25, and changing the operating condition of the
A lot of perforations 74 and 75 are formed at the perforated 60 propeller 80.
The information from the vessel conditions determination
plates 72 and 73. The positions of the perforated plates 72 and73 are laterally displaced from each other, thereby forming an unit 100 and information from the oceanographic condition
arrangement with the perforations in a displaced manner. determination unit 120 are transmitted to the condition setting
Since perforated plates 72 and 73 are arranged so as to dis unit 130. The condition setting unit systematically sets con
place the positions of the perforations, the perforated plates 65 ditions for injecting bubbles to the bottom3 of the vessel. The
72 and 73 function as a so-called baffle plates, which bend the conditions include starting/stopping injecting bubbles, which
air flow to provide resistance. Accordingly, in addition to ones of the air nozzles 21, 22, 23, 24 and 25 the bubbles areUS 9,376,167 B2
63
injected from, which inject rate is to be set, which timing theinjecting is started on, how a temporal bubble inject sequenceis composed, when injecting is started and stopped and the
like.

64
The comparator 140 compares the processed representa
tive value from the relative velocity sensors 55.56 and 57 andthe setting value preliminarily set by the condition setting unit
130 with each other. The number of working nozzles, theinject rate of bubbles, and the bubble injecting pattern are

The condition setting unit also sets the inject condition andthe operating condition of the air nozzles 21, 22, 23, 24 and 25 controlled.
The comparator 140 also compares the value detected byand the blowers 10, 11, 12, 13 and 14 along with bubble
convolvement, and the controlling thresholds of the thrust the draft sensor 111 and the setting value preliminarily set bytorque gage 83 and the vibration sensor 84 in order to change the condition setting unit 130 are compared with each other.
the operating condition of the propeller 80. In addition to the 10 The number of working nozzles and the inject rate of bubbles
thresholds, the condition setting unit further performs condi are controlled according to the draft of the hull 4. When swells
tion setting of the inject condition and the operating condition come, the valves 161,162, 163, 164 and 165 are controlled,according to the detection values from the thrust torque gage and the pressures acting on the air nozzles 21, 22, 23, 24 and83 and the vibration sensor 84, condition setting for changing 25 are finely adjusted quickly by increasing and decreasing.
the operating condition of the propeller 80, combination con 15 The comparator 140 also compares the inclination value ofdition setting, correction condition setting and the like. The the hull 4 detected by the inclination sensor 112 and thecondition setting instruction 131 for reducing the frictional setting value preliminarily set by the condition setting unit
130 with each other. The lateral inject spots of working air
resistance, and a condition setting instruction 131 for prevent
ing bubble convolvement are also input into the condition nozzles are changed responsive to the inclination of the hull 4.
setting unit 130.
and inject rate of bubbles is increased or decreased, thereby
According to the settings in the condition setting unit 130, allowing the frictional resistance to be effectively reduced.
the comparator 140 compares signals. The blowers 10, 11, 12.
Here, operation control on injecting of bubbles and the
13 and 14 and the propeller80 are controlled via the controller propeller using the signal from the convolvement detector
150. The controller 150 also controls the valves 161,162,163,

180 will be described. When bubbles are convolved into the

164 and 165 arranged on the discharge sides of the blowers 25 propeller 80, the apparent density of seawater on which the10, 11, 12, 13 and 14. These are attached for the sake of propeller 80 is acting is reduced. This causes the propulsion toadjusting the valves 161,162, 163, 164 and 165 and attains a be decreased, and varies the thrust power and the torque of thedesired air rate, in a case of controlling an air rate below the propeller drive shaft 82. The thrust torque gage 83 attached tocontrol region of the motors of the blowers 10, 11, 12, 13 and the drive shaft 82 detects this variation. In this case, detection
14, and in a case of quickly adjusting the waterline level using 30 may be made on the one. However, in this embodiment, bothof them are detected and output in order to improve accuracy.
the signal from the draft sensor 111.
Further, comparator 140 compares the detection signals In a region for a prescribed amount of convolvement, thefrom the thrust torque gage 83 and the vibration sensor 84 of propeller 80 vibrates. The vibration sensor 84 detects thethe convolvement detector 180 and the thresholds thereof set
vibration, applies processing, and output a signal thereof.
by the condition setting unit 130. When it is determined that 35 This embodiment uses both the thrust torque gage 83 and theconvolvement of bubbles above the threshold occur, the inject vibration sensor 84. However, any one of them may be suffi
conditions of the air nozzles 21, 22, 23, 24 and 25 and/or thecient.

In this embodiment, the thrust torque gage 83 is used
operating conditions of the blowers 10, 11, 12, 13 and 14 arechanged, and the inject conditions are thus changed to those mainly, and the vibration sensor 84 is used auxiliary forbased on which the propeller 80 does not easily convolve the 40 complement. The signal from the convolvement detector 180
bubbles. When it is determined that convolvement of bubbles
is transmitted to the comparator 140.
The detection values from the thrust torque gage 83 and theabove the threshold occurs, the operating conditions of thepropeller 80 are changed. This prevents the reduction in pro vibration sensor 84 are also used as detection signals whenpeller efficiency from continuing, and reduces generation of cavitations occur at the propeller 80. The comparator 140
vibration and noise and damage to the propeller 80. Under 45 compares the thresholds as the setting values of the thrustcertain situations, the operating conditions of the propeller 80 power and the torque set by the condition setting unit 130 andare changed, thereby maintaining the propulsion. These the values of the thrust power and the torque detected by thechanges in the inject condition of bubbles, the blower oper convolvement detector 180 with each other. The threshold asating conditions, and the operating conditions of the propeller the setting value of vibration set by the condition setting unit
are used solely or in combination. The priority condition, 50 130 and the detection value detected by the vibration sensor
changing procedures and the like are pursuant to the condition 84 are compared with each other. If any one of these threesetting instruction 131 for reducing the frictional resistance, detection values falls below or exceeds the threshold, theand the condition setting instruction 131 for the bubble con number of working nozzles, the spots, and the inject rate of
bubbles are controlled.
volvement prevention.
The signals from the shear force sensors 51, 52,53,54 and 55 The bubble injecting control is performed by controlling
55 attached on the bottom 3 of the vessel are fed back to thethe air nozzles 21, 22, 23, 24 and 25, the blowers 10, 11, 12,comparator 140, compared with the share force value prelimi 13 and 14, and the valves 161, 162, 163, 164 and 165. The
narily set by the condition setting unit 130. The operating basic concept is to change the inject condition of bubbles
conditions of the blowers 10, 11, 12, 13 and 14 are finely when occurrence of convolvement of bubbles into the propel
adjusted via the controller 150 pursuant to a prescribed rule 60 ler 80 is detected. For example, the valves 161,162, 163, 164
according to the deviation, an algorithm and constants. The and 165 are controlled and the amount of bubbles is finely
relative velocities between the hull 4 and seawater are
adjusted; the blowers 10, 11, 12, 13 and 14 are controlled anddetected by the relative velocity sensors 55, 56 and 57, and the amount of bubbles are decreased, thereby eliminating the
Subjected to the prescribed Statistical processing, and the convolvement of bubbles into the propeller 80; the working
representative value is transmitted to the comparator 140. The 65 nozzles among the air nozzles 21, 22, 23, 24 and 25 aresignals from the draft sensor 111 and the inclination sensor changed, and for example the injecting of bubbles from the air
nozzle 23 disposed at the center is stopped by changing
112 are also transmitted to the comparator 140.

US 9,376,167 B2
65nozzles; or the air nozzles 22, 23 and 24 are stopped. The
control of the number of nozzles, spots, and inject rate ofthese air nozzles 21, 22, 23, 24 and 25, blowers 10, 11, 12, 13
and 14, and valves 161,162, 163, 164 and 165 can be used in

66
conditions of the propeller 80 can increase the number of
revolutions, and decrease the number of revolutions foraddressing vibration and noise. The change in operating con
dition of the propeller 80 allows the influences owing to

any combination. However, the optimal combination is pre convolvement of bubbles to be reduced. When cavitations
liminarily acquired on the basis of a simulation, a model occur at the propeller 80, use of the detection values from theexperiment, and a substantiative experiment. The optimal thrust torque gage 83 and the vibration sensor 84 can Suppress
control condition is set by the condition setting unit 130.
occurrence of vibration and noise at the propeller 80, and also
In these optimal controls, the signals from the oceano prevent damage to the propeller 80.
graphic condition determination unit 120 and the vessel con 10 Here, effects of the V-shaped mound 190 and the wrapping
ditions determination unit 100 are also used. For example, portion 191 will be described.
The bubbles injected from the air nozzles 21, 22, 23, 24 andwhen the currents detected by the current sensor 123 is mov
ing from a right diagonal to a left diagonal with respect to the 25 to the bottom3 of the vessel flow along the bottom3 of thetraveling direction of the vessel 1, the bubbles are also drifted vessel, and are guided by the end plates 5.5", 6, 6', 7 and 7".
a little by the currents. Even under conditions where the 15 However, a part of the bubbles rises along the sides 8 of the
convolvement of bubbles into the propeller 80 is typically vessel to the surface of the sea. As the bubbles approach thedetected and the air nozzles 22, 23 and 24 are stopped, in this propeller 80 side on the bottom 3 of the vessel, the bottom 3
case, this condition is changed to a condition for stopping the of the vessel is gradually narrower, and the sides 8 of the
air nozzles 21 and 22. When, for example, the engine opera vessel are gradually inclined. A part of bubbles having flowed
tion detector 103 detects change in output of the engine driv along the inclined surface from the upstream direction winds
ing the propeller 80, the thrust power and the torque of the around the slanted sides 3 of the vessel and rises to the water
propeller drive shaft 82 are changed as a matter of course.
surface. However, a considerable amount still flows along the
Further, the threshold set by the condition setting unit is bottom 3 of the vessel. When the bubbles reach the V-shaped
corrected in consideration of the change in output. This mound 190, the V-shaped mound 190 causes the bubbles toenables the thrust power and the torque against the convolve 25 move apart from the bottom 3 of the vessel, as shown in FIG.
ment of bubbles to be appropriately evaluated.
28. This is because of effects that the shape of the V-shaped
In any event, when the convolvement detector 180 detects mound 190 is a structure slightly low at the fore portion andthe convolvement of bubbles into propeller 80, the air nozzles protuberant at the aft portion and Smoothly continuous,
thereby causing the bubble to leave the bottom3 of the vessel.
21, 22, 23, 24 and 25, the blowers 10, 11, 12, 13 and 14, andthe valves 161,162, 163, 164 and 165 are controlled, and the 30 The bubbles wind to the sides 3 of the vessel at the V-shaped
operation conditions, such as the number of working nozzles, mound 190 are guided to the water surface by the wrapping
the spots and the inject rate of bubbles, are changed. This portion 191 having a similar protuberance. This further preprevents the bubbles convolved into propeller 80, and pre vents the bubbles from flowing along the sides 3 of the vesselvents the reduction in propeller efficiency from continuing. toward the propeller 80.
Further, this can prevent vibration and noise at the propeller 35 FIG. 29 shows the situations of the flow around the propel
80 along with the convolvement of bubbles from occurring, ler 80. FIG. 29 illustrates how flow velocities around the
reduce damage to the propeller 80, and prevent a harmful propeller 80 distribute with respect to the navigational speed
effect on vessel 1. Thus, the bubble injecting control improves of the vessel 1. Lines where the velocities become slower by
10%. 20% and 30% with respect to the navigational speed are
the thrust power, the torque and the detection value of thevibration. When every detection value exceeds or falls below 40 represented as iso-velocity lines. As apparent in FIG. 29, thethe threshold, the injecting of bubbles are returned to the flow velocities around the propeller 80 distribute in a substan
tially V-shaped manner. The velocities are high at lower part
original control conditions.
Next, the control of changing the operating conditions of of the propeller 80, and low at the upper part. In view ofthe propeller 80 when convolvement of bubbles is detected propulsion of the vessel 1, the lower the flow velocities exert
will be described. When the detection value detected by the 45 on the propeller80, the higher the efficiency is. In comparison
thrust torque gage 83 falls below the threshold, and the con with the upper and lower parts of the propeller 80, the upper
volvement of bubbles into the propeller is detected, in a case part effectively acts in view of propulsion. On the other hand,of performing output-oriented control, the output of the in view of the effect of bubbles, as a phenomenon, bubbles
engine is increased, the rotation of the propeller drive shaft 82 escape in a direction where the water pressure is low. If theis increased, and the thrust power and the torque are returned 50 Velocity is high, the dynamic pressure component becomesto the original. In this case, the propeller efficiency falls and high and the static pressure component becomes low, accord
the engine efficiency usually falls too. However, the output of ing to the Bernoulli theorem. That is, in comparison at thethe propeller 80 is maintained. Accordingly the hull velocity same level of depth of water, the bubbles tend to accumulate
and the like do not fall. Under characteristics and conditionsat an area with a high flow velocity, and tend to escape from
where the engine efficiency is not decreased even if the rota 55 an area with a low pressure.
The effects of the V-shaped mound 190 includes effects
tion is increased, the operation can be continued without
decreasing the engine efficiency. In a case of performing that separate the bubbles from the bottom 3 of the vessel by
efficiency-oriented operation with respect to propeller 80, the the V-shaped mound 190, lower the streamline downward
output of the engine is decreased, the rotation of the propeller further from the bottom 3 of the vessel, and slows the flow
drive shaft 82 is decreased, and the thrust power and the 60 velocities at the lower part of the propeller 80. Accordingly,
torque are further decreased. This attains results that alleviate presence of the V-shaped mound 190 exerts an effect thatthe convolvement of bubbles into the propeller 80, recover the separates the bubbles from the bottom 3 of the vessel, andoverall propeller efficiency, do not cause much decrease in causes the bubbles quickly wind around the sides 8 of thethrust power and the torque, and can prevent vibration and vessel. Since the flow velocities of the lower part of the
65 propeller 80 are slowed, an effect that suppresses convolve
noise along with convolvement of bubbles.
Thus, when the propulsion of the propeller 80 decreases ment of bubbles into the propeller 80, and an effect thatalong with convolvement of bubbles, change in operating improves the propulsion of the propeller 80 are exerted. Fur

US 9,376,167 B2
6768
ther, since the V-shaped mound is formed so as to laterally view. This exerts a high bubble separating effect, and canspread centered at the planar center line CL of the hull 4, the prevent foreign matters from being mixed from the ocean into
bubbles can escape symmetrically and effectively apart from the pump 207 or the pipe 97. These bubble intake B, gas
the propeller 80 arranged symmetrically on the planar center liquid separation chamber 86, blower 208, pump 207 and theline CL. Since the mound has the substantially V-shape, like configure the bubble drawing system.
increase infrictional resistance of the flow along the bottom 3
With such a configuration, the bubble intake Barranged inof the vessel against the hull 4 is further suppressed. The fore of the propeller 80 draws the bubbles to be convolved into
symmetric shape facilitates manufacture thereof. As to effects propeller 80 in advance, and reliably prevents the bubblesof the mound, since the mound can be formed as the protu from reaching the propeller 80, thereby preventing the pro
berance made of a strength member at the bottom 3 of the 10 peller efficiency from decreasing. The bubble intake B isvessel, the operation can proceed without any obstacles when arranged in the proximity of the propeller 80. Accordingly,
the vessel 1 is carried in a dock and mounted on bases. The
the frictional reduction effect by bubbles injected to the bot
V-shaped mound 190 may be made of a strength member. tom 3 of the vessel is sufficiently exerted, and subsequently
This improves the strength in fore and aft directions at the the bubbles are drawn and discharged to the outside, where
bottom 3 of the vessel, and realizes a strong hull structure 15 reconvolvement does not occur, thereby Sufficiently exerting
against bending Owing to redundant wave forces (sagging and the frictional reduction effect. Even in case of trouble in any
hogging) exerted on the vessel 1.
one of the blower 208 of the bubble drawing system and thepump 207, convolvement of bubbles can be prevented to a
Seventh Embodimentcertain extent by closing the valve of the system concernedand opening the air valve 206b of the air discharge pipe 92.
FIG.30 shows a seventh embodiment of the present inven
The bubble-mixed seawater drawn from the bubble intake
tion. The seventh embodiment will be described only on B is separated to sucked-in bubbles and water by the gas
difference from the sixth embodiment. Other elements haveliquid separator 86. This eliminates mixture of water into thethe same configurations as those of the sixth embodiment.
blower 208 and the pump 207, and is capable of stably exert
In FIG. 30, the air nozzles 21, 22, 23, 24 and 25 injecting 25 ing the function. The water separated by the gas-liquid sepa
bubbles are arranged on the bottom 3 of the vessel 1. On the rator 86 can be used for another application for the vessel 1,other hand, a bubble intake 85 drawing bubble-mixed seawa Such as the cooling water, Supply water for the anti-rollingter is arranged in fore of the propeller 80 provided at the stern tank.
9 of the hull 4. FIG. 31 shows the detail of this part together
30
with the gas-liquid separator.
Eighth Embodiment
In FIG. 31, a gas-liquid separation chamber 86 as gas
liquid separation mechanism is formed inside of a bubble
FIGS. 32 and 33 show an example of an eighth embodi
intake Barranged at the bottom 3 of the vessel. The bubble ment of the present invention. The eighth embodiment is anmixed seawater drawn from the bubble intake B enters theexample of combination between the previous V-shaped
gas-liquid separation chamber 86 via the cylinder 87. The 35 mound and the bubble drawing system.
gas-liquid separation chamber 86 is formed so as to secure a
However, in the eighth embodiment, a bubble intake 99 has
sufficient volume. The bubble-mixed seawater flowed therea Substantially V-shaped appearance in conformity with theinto is sufficiently slowed down and the bubbles rise and V-shaped mound 190, and is disposed in fore of the V-shaped
accumulated as air. An air intake pipe 91 is connected to the mound 190, as shown in FIG. 32.
gas-liquid separation chamber 86. The air intake pipe 91 is for 40 FIG.33 shows the detailed operation thereof. The V-shaped
discharging the air accumulated in the upper part by the mound 190 for preventing the convolvement of bubbles isblower 208 from the air connection pipe 203 via the air valve arranged in the aft of the bubble intake 99. Accordingly, even
206a, to the outside such as the atmosphere, where the pro if the bubbles having not been drawn yet flow out of thepeller 80 does not cause reconvolvement. An air discharge bubble intake 99 owing to various disturbances, the V-shaped
pipe 92 discharging air is connected to the upper part. The air 45 mound 190 can cause the bubbles to escape, and reliably
valve 206b is provided also at the air discharge pipe 92. The prevent convolvement into the propeller 80. According to a
bubble separation filter 202 having a lot of apertures is pro case where the amount of bubbles is small, situations of thevided at lower part of the gas-liquid separation chamber 86. vessel 1, and the navigational condition, the blower 208 andHere, a resistant effect by the multiple apertures further sepa the pump 207 are stopped, thereby enabling only therates the bubbles having not risen well. The seawater from 50 V-shaped mound 190 to operate. This allows the reduction
which bubbles have been drawn is drawn by the pump 207 effect of the net frictional force to be improved in a finerfrom the water intake pipe 94 via the water valve 206C, and manner. The V-shaped mound 190 is arranged in the proxim
transferred via the water pipe 97 for use for cooling water and ity of an aft region of the bubble intake 99. In addition to theanti-rolling tank of the vessel 1. A water level sensor 98 for above effect of the V-shaped mound 190, this exerts an effectdetecting the water level is provided at the gas-liquid separa 55 that causes the bubbles to escape because the flow velocity istion chamber 86. The number of revolutions of the blower 208
lowered at the V-shaped mound 190, and an effect that facili
is controlled so as to provide certain air accumulation in the tates that the bubbles having escaped is drawn from theupper part. The blower 208 is a positive-displacement type bubble intake 99.
even capable of blowing seawater-mixed bubbles, and madeNinth Embodimentof an anti-corrosion material. The air connection pipe 203 60
faces downward from the top surface of the gas-liquid sepa
ration chamber 86, to which the air discharge pipe 92 isFIG. 34 shows a ninth embodiment of the present invenconnected, and has a structure where the air is left in the upper tion. FIG.34 (a) shows a perspective view thereof. FIG.34 (b)part even if the balance of the pump 207 and blower 208 is shows an elevation view from the stern. Bubble protection
lost, and absorbs the pulsing of pressure while the pump 207 65 plates 3200 and 3201 are arranged symmetrically at a propel
operates. The bubble separation filter 202 is formed as a ler attachment section 9' at the stern so as to develop from anconical shape, and disposed in a slanted manner in a sectional elongated section 3' of the bottom of the vessel in a substan

US 9,376,167 B2
69
70
stablefrictional
resistance
reductioneffect of the hull 4. In
tially V-shaped manner when viewed from the stern. The
bubble protection plates 3200 and 3201 are provided so as to particular, the substantially V-shaped mound 190 exerts
be fixed to an elongated section 8 of the sides of the vessel, effects that separate the bubbles flowing along the bottom3 ofand formed so as to develop also toward the propeller 80 aft. the vessel from the bottom3 of the vessel, prevent the bubbles
A lot of round apertures 3202 are perforated at the bubble from flowing into the propeller 80, slow the flow velocity at
protection plate. The bubbles injected from the air nozzles 21, the lower part of the propeller 80 by the V-shaped mound 190,
22, 23, 24 and 25, flowing from the upstream and nearly suppress the reconvolvement of bubbles, and improve thedrawn by the propeller 80 are baffled by the resistance of the propulsion of the propeller. In particular, the shape of the
bubble protection plates 3200 and 3201, and flow away along substantially V-shaped mound 190 is a structure slightly low
the shape of the bubble protection plates 3200 and 3201 while 10 at the fore portion and protuberant at the aft portion andspreading around the propeller 80. On the other hand, the smoothly continuous. This makes these effects remarkable.
The substantially V-shaped mound 190 can beformed so as
seawater flows into the inside of the bubble protection plates
3200 and 3201 by rotation of the propeller 80 from the round to have a strength member as the protuberance at the bottom
apertures 3202 perforated at the bubble protection plates 3 of the vessel. Accordingly, there is no obstacle when the3200, and 3201 and reaches the propeller 80. In this case, in 15 vessel 1 is carried on the bases under docking situations,comparison with a case without the bubble protection plates thereby facilitating the operation.
The mound has the Substantially V-shape. Accordingly, the3200 and 3201, the distribution of velocities of flow at thelower part of the propeller is slightly slow, owing to presence configuration with the strength member improves theof the bubble protection plates 3200 and 3201. This improves strength of the bottom 3 of the vessel in the fore and aft
the propulsive efficiency of the propeller 80, and allows effi directions, and realizes a hull structure strong against bending
cient operation from an overall aspect.
owing to redundant wave forces exerted on the vessel 1.
The bubble protection plates 3200 and 3201 are arranged inThus, the bubble protection plates 3200 and 3201 cause thebubbles to escape away from the propeller 80, slow the flow the proximity and in fore of the propeller 80, where the flow
velocity of seawater flowing along the hull 4 to flow therein, Velocity is high. This can prevent the oceanic floating mattersand slow the distribution of velocities of flow around the 25 and algae from being tangled into the propeller 80.
The bubble protection plates 3200 and 3201 are made of
propeller 80. This therefore exerts effects that slow the dis
tribution of velocities of flow at the lower part of the propeller stainless perforated plate having the round apertures anticor
and improves the propeller efficiency. Only for the purpose rosive to seawater. This can reduce the occurrence of stressthat bubble protection plates 3200 and 3201 cause the bubbles corrosion owing to residual stress at the edges, and increase
to escape and prevent the efficiency of propeller 80 from 30 corrosion resistance.
being decreased, the apertures 3202 are unnecessary. The
The bubble intake B at least drawing bubbles is arranged atbubble protection plates may be elongated more upward or the aftofthe air nozzles 21, 22, 23, 24 and 25 and infore of themore aft, or shortened downward or more fore. In any event, propeller 80, draws the bubbles to be convolved into propeller
presence of the bubble protection plates 3200 and 3201 80 in advance, causes the bubbles not to reach the propeller
allows the amount of convolvement of bubbles into the pro 35 80, and discharges the drawn bubbles to atmosphere or thepeller 80 to be reduced, and can prevent the propulsive effi outside, where reconvolvement does not occur. This can reliciency of the propeller from being decreased, even with vary ably prevent the convolvement. Further, the bubble intake B ising degrees. The multiple round apertures 3202 are perforated arranged in the proximity of the propeller 80. Accordingly,
at the bubble protection plates 3200 and 3201. If a shape with the frictional reduction effect by the bubbles injected to theedges such as square apertures is adopted, in a case where the 40 bottom 3 of the vessel is sufficiently exerted. Subsequently,
bubble protection plates 3200 and 3201 are configured with the bubbles are drawn, and the frictional resistance is reliably
stainless steel, the residual stress at the edges owing to press reduced. In case of trouble in the blower 208 or the pump 207,
ing facilitates stress corrosion. As measures therefor, the convolvement of bubbles can be prevented to a certain extent
round apertures, whose residual stress is Small when being by opening the air valve 206b of the air discharge pipe 92.
pressed, are perforated. Further, as to the effect of the bubble 45 The bubble separation filter 202, which is arranged at theprotection plates 3200 and 3201, since these plates are lower part of the gas-liquid separation chamber 86 and has aarranged at a region in fore of the propeller 80 where the flow lot of apertures allows the bubble separating effect to be
Velocity is high, it is prevented that the oceanic floating mat improved, and can prevent mixture of foreign matters fromters and algae are tangled into the propeller 80.
the ocean into the pump 207 or the pipe 97.
The advantageous effects of the sixth to ninth embodi 50 The substantially V-shaped mound 190 is arranged in thements as described above will hereinafter be described.
proximity of the aft region of the bubble intake 99. Accord
First, the configuration includes the vessel 1, the air nozzles ingly, the flow velocity is decreased at the substantially21, 22, 23, 24 and 25 injecting bubbles at least to the bottom V-shaped mound 190. This exert an effect of causing the
3 of the vessel 1, the blowers 10, 11, 12, 13 and 14 blowing air bubbles to escape, and facilitates that the bubbles having
to the air nozzles 21, 22, 23, 24 and 25, the propeller 80 55 escaped are drawn from the bubbles intake 99.
The thrust torque gage 83 detecting the convolvement of
arranged at the stern 9 of the hull 4 of the vessel 1, and thesubstantially V-shaped mound 190, which prevents the con bubbles into propeller 80 and the vibration sensor 84 arevolvement of bubbles into propeller 80, at the aft of the air provided. When the gage or the sensor detects the convolve
nozzles 21, 22, 23, 24 and 25 toward the stern at least on thement of bubbles, the inject conditions of the air nozzles 21,
bottom 3 of the vessel.
60 22, 23, 24 and 25 and/or the operating conditions of theWith this configuration, the rise of the bubbles are impeded blowers 10, 11, 12, 13 and 14 are changed. This can preventby the bottom3 of the vessel itself, the bubble retaining effect further convolvement of bubbles, and prevent the efficiencyof the propeller 80 from being decreased. Further, this cancan be maintained, and a small amount of bubbles can effec
tively reduce the frictional resistance. The influences of prevent occurrence of vibration and noise at the propeller 80
waves are alleviated at the air nozzles 21, 22, 23, 24 and 25 65 along with the convolvement of bubbles, prevent the propeller
arranged on the bottom 3 of the vessel, in comparison with a 80 from being damaged, and prevent the harmful effect on thecase of arrangement on the sides of the vessel. This allows the vessel 1.

US 9,376,167 B2
71
72
When the thrust torque gage 83 detecting the convolvement engine (combustion chambers), an intercooler 4012 coolingof bubbles into propeller 80, or vibration sensor 84 detects air compressed by the turbocharger 4011 while maintaining
convolvement of bubbles, the operating conditions of the the pressure, an air Supply pipe 4013 transferring the com
propeller 80 are changed. Accordingly, if the propulsion of pressed air, a Scavenged gas receiver 4014 for accumulating
the propeller 80 is decreased along with the convolvement of 5 the compressed air, and the exhaust gas receiver 4015 forthe bubbles, the frictional force reduction effect is improved accumulating the generated gas combusted by the engine
by increasing the number of revolutions and reducing the 4010. A gas Supply or charged air bypass pipe 23, which
number of revolutions as measures against vibration and bypasses a part of gas Supply or charged air and guides the air
noise, while the harmful effect on navigation of the vessel 1 is to the air supply pipe 4030, is communicated with the air
also prevented. Further, when the cavitations occur, the detec 10 Supply pipe 4013. A scavenging bypass pipe 4024, whichtion values from the thrust torque gage 83 and the vibration bypasses a part of the scavenged gas and guides the gas to the
air Supply pipe 4030, is communicated with the Scavenged
sensor 84 are utilized, and occurrence of vibration and noiseat the propeller 80 is suppressed, and damage to the propeller gas receiver 4014. An exhaust gas bypass pipe 4025, whichbypasses a part of the exhaust gas and guides the gas to the air
80 is also prevented.
15 Supply pipe 4030, is communicated with the exhaust gas
Tenth Embodimentreceiver 4015. The other ends of the gas supply or charged air
bypass pipe 4023, the Scavenging bypass pipe 4024, and the
FIG. 35 is a diagram sectionally showing a inject gas con exhaust gas bypass pipe 4025 are sequentially connected totrol device according to one embodiment of the present inven the air supply pipe 4030.
FIG. 36 pertains to an embodiment where a inject gas
tion and an overview of a vessel equipped with this device. As
shown in this figure, a inject gas control device 4002 is control device 4002 is applied to a vessel used in the ocean.
mounted on a vessel 4001 according to the present applica FIG. 36 (a) shows a side sectional view of the vessel. FIG. 36
tion. The inject gas control device 4002 includes a main (b) shows a top view thereof. A part of a principal configura
engine 4010, which is a propulsive main engine of the vessel tion is represented in an exposed manner. A residual gas (or a4001. In addition thereto, as equipment, the vessel 4001 is 25 part thereof) of the turbocharger from the gas Supply or
equipped with mechanisms necessary for sailing of the ves charged air bypass pipe 4023 and/or the scavenging bypass
sel, including: a screw 4003 driven by the main engine 4010 pipe 4024 and/or the exhaust gas bypass pipe 4025 passes theto acquire the propulsion of the vessel; a rudder 4004 chang air Supply pipe 4030 having the bent portions, and is guided toing and adjusting the traveling direction by changing the the gas outlet 4040 arranged in the proximity of the bottom 9
waterflow using a plate of the vessel 4001 in the water; a deck 30 of the vessel. For example, in this embodiment, the gas outlet
4005 as a floorboard; a deck 4006 as an upper floor; and a 4040 is arranged at the fore of the bottom 9 of the vessel andchimney 4007 discharging exhaust gas 4008 from the engine in the proximity of the planar center line of the hull CL. The
4010 to air.
arrangement of the gas outlet 4040 in the proximity of the
A air supply pipe 4030 is sequentially communicated with bottom 9 of the vessel is for the sake of prolonging thethree bypass pipes, which are attached to the main engine 35 retention of the injected bubbles at the bottom 9 of the vessel
4010 and will be described later. The air supply pipe 4030, and alleviating variation in pressure owing to waves. The
which includes bent portions, is a pipe for transferring a gas arrangement at the fore in the proximity of the bottom 9 of thewith a certain pressure and temperature to the gas outlet 4040. vessel is for an object for retaining the injected gas over the
The piping is installed from a position of collecting the three entire bottom 9 of the vessel as much as possible. Accord
bypass pipes so as to be a shape where the piping plunges 40 ingly, the gas outlet 4040 may be at a spot other than theonce to a height around the bottom of the vessel, passes the bottom 9 of the vessel. The spot may be an appropriate one on
bent portions, is bent at a height higher than the waterline and or below the waterline.
laid Substantially horizontally, and passes the bent portions
As shown in this figure, the air supply pipe 4030 (or 5030)
and plunges in the direction toward the bottom of the vessel. is installed upwardly immediately after passing the main
The piping path thus passes once at a height of the waterline 45 engine 4010. This exerts advantageous effects specific to theor higher. This can prevent seawater from flowing reversely present application according to which a drafting force of theinto the gas outlets arranged on or below the waterline, and pressurized gas or the exhaust gas that still retains heat
avoid dangerous situations of the main engine in view of complements the frictional resistance of the air Supply pipe
security. The gas outlet 4040, which is arranged at or in the 4030 (5030), and can secure the gas supply or charged air rate.
proximity of the bottom of the vessel and injects bubbles from 50 Alternative gas outlets 4040 may adopt a planer arrange
an opening perforated at or in the proximity of the bottom of ment (not shown) so as to be plurally and symmetricallyarranged with respect to the planarcenterline CL. In this case,the vessel into the water near the bottom 9 of the vessel, isconnected to the other end of the air supply pipe 4030. A the air supply pipes 4030 whose number corresponds to thatheater 4050 for heating gas passing through the air Supply of the gas outlets 4040 may be arranged. Instead, branchedpipe 4030 is arranged before the gas outlet 4040 of the air 55 pipes from the air supply pipe 4030 may be arranged corre
supply pipe 4030. A flowmeter 4035 is attached to a part of the spondingly with respect to the arrangement number. This
air supply pipe 4030 on or below the waterline. The gas allows the configuration to be simplified and can facilitate theSupply or charged air or the scavenged gas is heated by the arrangement. Preferably, the number of the discharge ports isheater 4050 using the exhaust gas, thereby reducing the water an odd number, and a symmetric arrangement is adopted
Viscosity resistance. This further improves the resistance 60 where the center one is disposed on the planar center line CL.
It is preferable that end plates 4095,4096 and 4097 guiding
reduction effect of the vessel, thereby allowing reduction inresistance to be further improved. As a driving source of the bubbles in order not to let the bubbles injected from the gas
heater 4050, the exhaust gas from the turbocharger 4011 may outlet 4040 escape bearranged at the bottom 9 of the vessel.
be utilized. Instead, an energy generator Such as an electric In a case of arranging a plurality of the gas outlets 4040, the65 end plates are also arranged symmetrically with respect togenerator that is arranged separately may be used.
The main engine 4010 includes a turbocharger 4011 having planar center line of the hull CL. In addition thereto, shear
a mechanism for forcedly blowing compressed air into the force sensor (not shown), which is a shear force detector

US 9,376,167 B2
73
detecting shear forces exerted on the hull owing to seawaterand bubbles, may be arranged on the bottom 9 of the vessel,
for example, at the stern.
Relative velocity sensors 55, which are relative velocity
detectors, are arranged at the stern. Other relative velocity
sensors 57 are arranged at the sides of the vessel. The relative
Velocity sensors 55 are arranged apart from the gas outlet
4040. The relative velocity sensors 57 are arranged at spots

74
resin, the shapes of the perforations are arbitrary in view ofcorrosion. However, in view of molding, round perforations
are preferable.
FIG.37 is a system diagram showing a system bypassing aturbocharger 4011 according to the present application. The
mechanism of the Surplus air bypass from the turbocharger
according to the present application will be described using
FIG. 37.

The turbocharger 4011 includes a compressor 4110 thatdraws
atmosphere through a filter 4111 and compresses thein the proximity thereof. In particular, the relative velocity air, a turbine
4112 that rotationally drives the compressor
sensors 57 are disposed at lower parts on the sides 8 of the 4110, and a shaft
connecting these. According to the mecha
vessel, on which influences of waves are not exerted. An
nism
of
the
turbocharger
energy of the exhaust gas
ultrasonic system is adopted for these relative Velocity sen (temperature and pressure)4011,
having been discharged from thesors 55 and 57. This allows use in the ocean, and reduces 15 exhaust gas pipe is utilized. The turbine 4112 is driven andinfluences owing to waves and currents.
rotates at high speeds. The compressor 4110 is driven by this
The video cameras 58 and 59 for monitoring conditions of rotational force. The compressed air is transferred into theinjected bubbles are arranged at fore and aft parts of the cylinders 4016 of the main engine (hereinafter, also referredbottom 9 of the vessel. Images taken by these video cameras to as the "cylinder for the sake of the simplicity). Accord
58 and 59 are monitored by a person and utilized for analyz ingly, an amount of mixture over an amount of original aspi
ing the inject condition of bubbles.
ration of an internal combustion engine is aspirated and com
The air nozzles will be described using the figure of the first busted, thereby acquiring an output over an apparent piston
embodiment. FIG.3 is a perspective view conceptually show displacement.
High temperature and pressure exhaust gas generated bying the detailed structures of the air nozzles 4040. For the sakeof simplicity of description, FIG. 3 shows a typical example 25 combustion of fuel in each cylinder 4016 is accumulated inof the air Supply pipes and the air nozzles. The air bypassed the exhaust gas receiver 4015 during the exhaust gas valve is
via the air Supply pipe 16 connected to the air Supply pipe opened. The pressure is caused to be static pressure. Adiabatic
4030 are bent at a chamber 70 of the gas outlet 4040 con expansion is accomplished at the turbine nozzle 4116 and thenected to the air supply pipe 16. A distribution component 71 turbine 4112. This generates turbine driving force, and rotates
having triangular profile for dispersing the blown air is 30 the turbocharger compressor 4110 directly connected thereto.
arranged immediately below the connection part of the air The turbocharger compressor 4110 draws air from the out
supply pipe 16. A configuration is adopted according to which side, and applies adiabatic compression. The air is caused tothe air is bent at right angle at this part and dispersed laterally be static pressure at a diffuser 4113 at an outlet of the com
by the distribution component 71. As the air is bent at right pressor 4110. This generates high pressure and temperature
angle, the air tends to uniformly spread along directions in a 35 air (gas Supply or charged air). The air is cooled by an air
horizontal plane. However, the air tends to flow only toward cooler 4112, accumulated in the scavenged gas receiver 4014.
perforated plates 72 and 73 in front thereof by presence of and supplied to the cylinder 4016. In cases where the load oninterior walls of the chamber 70 in the recess and at the right, the engine 4010 is low and the energy of the exhaust gas isleft, top and bottom. Here, presence of the distribution com insufficient, such as a case immediate after startup, an auxil
ponent 71 further uniformizes the lateral distribution of the air 40 iary blower 4115 is actuated, draws air and support the opera
tion of the turbocharger compressor 4110. In this configura
with respect to the perforated plates 72 and 73.
A lot of perforations 74 and 75 are formed at the perforated tion, according to the present application, the gas Supply orplates 72 and 73. The positions of the perforated plates 72 and charged air bypass pipe 4023, the Scavenging bypass pipe
73 are laterally displaced from each other, thereby forming an 4024, the exhaust gas bypass pipe 4025 are provided andarrangement with perforations in a displaced manner. This 45 bypass the residual gas.
embodiment shows an example using two perforated plates
In more detailed operation, first, atmosphere is drawn
72 and 73. Instead, the number thereof may be another num through the filter 4111. Compressed air is generated by theber, such as three or four. Since perforated plates 72 and 73 are compressor 4110 driven by the rotational force of the turbine
arranged so as to displace the positions of the perforations, the 4112, and communicated to the air supply pipe 4013 via theperforated plates 72 and 73 function as a so-called baffle 50 diffuser 4113. The gas supply or charged air bypass pipe 4023
plates, which bend the airflow to provide resistance. Accord is communicated with the air supply pipe 4013, as described
ingly, in addition to further uniformization of the air in the above. A part of the compressed high temperature air passes
through the gas Supply or charged air bypass pipe 4023 andlateral direction, the air in the vertical direction is also uni
formized, thereby enabling the air to be injected from a inject thus is bypassed. The draw of gas by this bypass is performed
55 by opening and closing the gas Supply or charged air bypass
port 76 on a front surface.
Here, the perforated plates 72 and 73 are manufactured by adjustment valve 4023A, whose starting, operating and stop
continuously making round perforations on a corrosion resis ping are controlled on the basis of sensing of after-mentioned
tant sheet metal such as stainless by a press, and the arrange physical quantities. The gas Supply or charged air acquired
ment with displaced perforation positions can be realized by through the bypass by the gas Supply or charged air bypass
cutting. This offers excellent productivity. If configured with 60 pipe 4023 is guided to the air supply pipe 4030.
The other airpassing the air supply pipe 4013 is intercooleda stainless material, since the perforations are round perfora
tions, edge portions are omitted, nearly preventing the stress by the intercooler 4012. The intercooled compressed air isfrom being concentrated when being pressed, in contrast to a dehydrated by the mist catcher 4114 disposed in the commucase with square perforations. This alleviates progress of nication pipe, passes through a movable gate, and communi
stress corrosion from the edge parts, even if used in seawater. 65 cated to the Scavenged gas receiver 4014. The gas may be
The perforated plates 72 and 73 may be manufactured by Supplied to the scavenged gas receiver 4014 also from theusing resin and by means of molding. In a case of using the auxiliary blower 4115 including an adjustment valve 4115A.

without influences of bubbles on the sides of the vessel even10US 9,376,167 B2
75
76
The scavenged gas and the exhaust gas are required for
The scavenging gas bypass pipe 4024 is communicated with
the Scavenged gas receiver 4014, as described above. A part of driving the turbocharger 4011 and in turn driving the engine
the compressed air accumulated in the Scavenged gas receiver 4010. The bypass rate should strictly be controlled according
4014 passes through the scavenging bypass pipe 4024 and to the heat load on the engine 4010. As a result of numerous
thus is bypassed. The draw of gas by this scavenging bypass researches, the inventors of the present invention have foundis performed by opening and closing the scavenging bypass that it is preferable to control the bypass rate on the basis ofadjustment valve 4024A, whose starting, operating and stop the physical quantities related to the heat load on the mainping are controlled on the basis of sensing of after-mentioned engine and the characteristics of the turbocharger. For
physical quantities. The gas Supply or charged air acquired example, the physical quantities may be a scavenging gas
through the bypass by the Scavenging bypass pipe 4024 is 10 pressure and an exhaust gas temperature (or an exhaust gas
pipe temperature, or an ambient temperature corresponding
guided to the air supply pipe 4030.
The other air accumulated in the scavenged gas receiver to an exhaust gas temperature in a one-to-one relationship).
4014 passes through the communication pipe and is guided to For example, the characteristics of the turbocharger may be
the cylinder 4016. In the cylinder 4016, fuel is added by turbocharger efficiency acquired by an after-mentioned
spraying and the like and combusted. The exhaust gas gener 15 method, or matching characteristics between the main engine
ated by the combustion is guided to exhaust gas receiver 4015. and the turbocharger. As to these physical quantities, neces
The exhaust gas bypass pipe 4025 is communicated with the sary values can be acquired by calculation or estimation using
exhaust gas receiver 4015, as described above. A part of the measurement of a part of temperatures, pressures and flow
exhaust gas accumulated in the exhaust gas receiver 4015 rates at paths and spots related to the turbocharger 4011 or thepasses through the exhaust gas bypass pipe 4025 and thus is main engine.
bypassed. The draw of gas by this exhaust gas bypass is
Here, control of a bypass rate of gas during use of theperformed by opening and closing the exhaust gas bypass residual gas by the turbocharger according to one embodi
adjustment valve 4025A, whose starting, operating and stop ment of the present application, is described.
FIG. 39 is a block diagram showing an arrangement ofping are controlled on the basis of sensing of after-mentioned
physical quantities. The gas Supply or charged air acquired 25 devices according to this embodiment, various sensors
through the bypass by the exhaust gas bypass pipe 4025 is acquiring basic data of control according to the present appli
guided to the air supply pipe 4030.
cation, actuators and the like for the sake of realizing the
The other exhaust gas in the exhaust gas receiver 4015 is control of the present application. As shown in this figure, aguided to the turbine 4112 via the turbine nozzle 4116 having barometric sensor S1 and an intake air temperature sensor S2
a narrow diameter. A part of this gas rotationally drives the 30 are arranged before entry of the filter 4111. A rotation speed
turbine 4112, and is communicated to the chimney 4007 as sensor S3 is arranged so as to be coupled to the compressor
the exhaust gas to be discharged.
4110 and the turbine 4112. A scavenging gas pressure sensor
With respect to the starting point of the invention of the S4 is arranged in the Scavenged gas receiver 4014. An exhaust
present application, as described above, there are actual situ gas pressure sensor S5 is arranged in the exhaust gas receiver
ations of a tremendous advance in turbochargers and resultant 35 4015. An exhaust gas temperature S6 and an exhaust gas mass
generation of residual gas. FIG. 38 is a diagram showing an flow rate sensor S7 are arranged between the exhaust gas
example of a relationship between a main engine loads and receiver 4015 and the turbine 4112. A post-turbine exhaustturbocharger efficiency. As shown in this figure, a consider gas pressure sensor S8 is arranged after the turbine 4112. A
able amount of surplus is actually generated with respect to a bypassed mass flow rate sensor S9 is arranged at the air
desired value of main engine efficiency. For example, when 40 Supply pipe 4030 communicated from the gas Supply or
the main engine load is 75.0%, 72.7% efficiency is actually charged air bypass pipe 4023, the Scavenging bypass pipe
acquired while the desired value of the main engine efficiency 4024 and the exhaust gas bypass pipe 4025.
FIG. 40 is a control block diagram for illustrating a control
is 68.0%. This difference causes the generation of the residualgas. This embodiment gives attention to that this generated system of the present application.
gas has originally been discharged in vain, and intends to 45 The functionality for realizing the control pertaining toefficiently utilize this gas.
present application includes: a control device 4200 that con
More specifically, the gas Supply or charged air or the trols the above-mentioned various bypasses on the basis of
exhaust gas is principally used as the bypass gas. Accord values acquired by the various sensors (S1 to S9) from theingly, the temperature of this gas is high. When the gas is turbocharger 4011 and the draft sensor 4230; a vessel condi
injected as bubbles, the water viscosity resistance is reduced. 50 tions determination unit 4300 for acquiring and determining
This exerts an advantageous effect specific to the present the vessel conditions (positional conditions, fuel conditions,application, which is further reduction infrictional resistance. operating conditions, etc.); an oceanographic condition deter
Typically, the entire amount of high pressure Scavenged mination unit 4400 for collecting and determining data pergas or exhaust gas, which is a product by combustion thereof, taining to ambient oceanographic conditions; a condition set
passes through the turbocharger exhaust gas turbine 4112, 55 ting unit 4220 for setting various conditions on the basis of or
and is used for driving the turbocharger compressor 4110. in comparison with determinations by the vessel conditions
However, as described in FIG.38, in the turbocharger having determination unit 4300 and the oceanographic condition
efficiency more than or equal to that required for the engine determination unit 4400; and a gas outlet 4040 that discharges
4010, it is not necessary to Supply the entire amount. As the bypassed gas, on which these functions have calculated
shown in FIG. 38, if the turbocharger efficiency is more than 60 optimal values, into the water around the bottom 9 of the
3% of that required by the engine, about 10% of the scav vessel.
enged gas or the exhaust gas can be bypassed without passing
The control device 4200 includes: a processor 42.01 thatthrough the turbocharger turbine 4112. In a case of driving the applies prescribed processing to the characteristics of thepower turbine (not shown), the exhaust gas bypass 4025 is turbocharger and data acquired by the various sensors (S1 toeffective. With respect to bubbles in this case, cooled high 65 S9 and 230); a basic data unit 4202 having a function ofpressure air, which is the Scavenging bypass 4024, is effec feeding basic data to the processor 4201; a turbocharger chartive.
acteristics unit 4203 having a function of calculating andUS 9,376,167 B2
77
acquiring information pertaining to the characteristics of theturbocharger and providing the information for the basic data
unit 4202; a comparator 4204 having a function of comparing
and calculating the values from the various sensors (S1 to S9and 230) and the values processed by the processor 4201; anda controller 4205 having a function of controlling the com
parator 4204. In particular, the processor 4201 also has afunction of calculating after-mentioned turbocharger effi
ciency on the basis of detection results from a prescribed78
rents and the like including information on a general weather,and is used for determining that for example the injecting of
bubbles is stopped when the oceanographic condition isstormy, and bubbles are generated when the condition is

The vessel conditions determination unit 4300 includes a

4040 downstream from the bottom 9 of the vessel. In order torecovered.
The information from the vessel conditions determination

unit 4300 and information from the oceanographic condition
determination unit 4400 are transmitted to the condition set

ting unit 4220. The condition setting unit 4220 systematicallysensor and the like.
10 sets conditions for injecting bubbles to the bottom 9 of the
The vessel conditions determination unit 4300 is equipped vessel or in the proximity thereof. The conditions include
with a GPS 4310 detecting a location of the vessel, a fuel starting/stopping injecting bubbles, which ones of the gas
measurement unit 4320 measuring a fuel consumption of the outlets 4040 the bubbles are injected from in a case of includ
engine of the vessel, and an engine operation detector 4330 ing a plurality of the nozzles, which inject rate is to be set,detecting the operating conditions of the engine of the vessel. 15 which timing the injecting is started on, how a temporal
The vessel conditions determination unit 4300 particularly bubble inject sequence is composed, when injecting is started
determines present conditions of the vessel, and determines and stopped and the like. In the condition setting unit 4220,
present conditions that vary in a small degree or vary slowly the conditions for injecting bubbles are set such that shear
during sailing. For example, the GPS 4310 grasps the location forces acting on the hull, the relative velocity of the hull, theof the vessel on the map, and detects distances to ports and draft, the inclination and the like are also considered. Condi
destinations, an absolute velocity with respect to the ground tion setting for control according to these signals is also
and the like.
performed. The condition setting unit 4220 performs condi
This is utilized for determining which position or location tion setting according to a condition setting instruction foron the map bubbles are injected or stopped. The measurement reducing the frictional resistance, and further performs conof the absolute velocity with respect to the ground is also used 25 dition setting according to condition setting instruction forfor the sake of complementing the rotation speed sensor S3. adjusting the waterline level by means of injecting bubbles.
According to the settings in the condition setting unit 4220.
The fuel measurement unit 4320 is used for measuring how
much fuel the engine consumes in a prescribed time period, the comparator 4204 compares signals. The flow rates and gas
and used for stopping injecting bubbles when the fuel con acquiring rate of bypass adjustment valves 4023A, 4024A
sumption efficiency becomes lower than prescribed fuel con 30 and 4025A are controlled by the controller 4205. The con
sumption efficiency. The engine operation detector 4330 troller 4205 also controls the valve arranged on the discharge
detects the operating conditions of the engine of the vessel, sides of auxiliary blowers (not shown). These are attached forand is used for acquiring information for stopping injecting of the sake of adjusting valves of the auxiliary blowers andbubbles when the operation of the engine is stopped, and for attaining a desired air rate, in a case of controlling an air rate
starting operation and, prescribed time period thereafter, 35 below the control region of the motors of the inverters of thestarting injecting bubbles. The engine operation detector auxiliary blowers, and in a case of quickly adjusting the4330 is also used for detecting the numbers of revolutions of waterline level using the signal from the draft sensor 4230. As
the engines and changing the number of working gas outlets to situations where bubbles are injected from the gas outlets
and/or inject rate of bubbles. In addition thereto, the vessel 4040, inject conditions of the bubbles and conditions whereconditions determination unit 4300 includes an engine output 40 the bubbles stays at the bottom 9 of the vessel and the prox
detector, a gyro, radar, and means for determining conditions imity thereofare imaged by the video camera 57. The images
where the vessel resides, such as amount of freight measure are utilized for analyzing and examining conditions of inject
ing air.
ment, condition of ballast water, and the like, and can beutilized for the bubble injecting control according to the pur
At the bottom 9 of the vessel and the proximity thereof, the45 shear force sensors (not shown) are attached to the gas outlets
poses.
navigational condition detection unit, which is not shown. deepen analysis of variation in shear force owing to injecting
The navigational condition detection unit includes the rela of bubbles, a corresponding number thereof are attached.
tive velocity sensors 55 and 57, a draft sensor 4230 detecting Signals from the shear force sensors are fed back to thethe waterline level of the hull, and an inclination sensor (not 50 comparator 4204. The signals are compared with shear force
shown) detecting so-called rolling, which is lateral inclina values preliminarily set by the condition setting unit 4220.
tion with respect to the traveling direction of the hull. Sepa The operating conditions of the blowers and/or bypass adjust
rately therefrom, a configuration also including a shear force ment valves 4023A, 4024A and 4025A are finely adjusted via
sensor (not shown) may be adopted. The navigational condi controller 4205 pursuant to a prescribed rule, an algorithm
tion detection units detect physical quantities which relatively 55 and constants according to the deviations. Further, the relativeeasily vary along with sailing of the vessel or are controlled velocities between the hull and seawater are detected by thefor the sake of variation. In addition thereto, the navigational relative velocity sensors 55 and 57 and subjected to a prescribed Statistical process, and the representative value iscondition detection unit includes sensors detecting Swaying,pitching, Surging, heaving and yawing of the hull.
transmitted to the comparator 4204. Signals from the draftThe oceanographic condition determination unit 4400 60 sensor 4230 and the inclination sensor (not shown) are alsotransmitted to comparator 4204.
includes a wave sensor 4410, a wind sensor 4420 and acurrent sensor 4430. The wave sensor 4410 detects the wave
First, the comparator 4204 compares the processed repre
heights, directions and periods of waves. The wind sensor sentative value of the relative velocity sensors 55 and 57 and4420 detects wind velocities and directions of winds. The
the condition setting value preliminarily set by the condition
current sensor 4430 detects current velocities, directions and 65 setting unit 4220 with each other. For example, in a caseheights of currents. The oceanographic condition determina where the gas outlet 4040 resides as a plurality of gas outlets
tion unit 4400 considers information on waves, winds, cur
4041, 4042, 4043, 4044 and 4045 when the relative velocity

US 9,376,167 B2
79
of the hull exceeds the setting value, controls can be performed including increase of the number of working gas

80
Measures for the cases of Such rolling adopt a configuration where a plurality of gas pipe systems are separately
provided so as to be capable of separately setting pressures.
outlets 4040 to 4045, increase of the amount of bubbles, orincrease of both of them according to the deviations. When Accordingly, even if there arise a height difference (presence
the relative velocity becomes lower than the setting value, of inclination) between starboard and port, desired injecting
controls can be performed including decrease of the number of bubbles (e.g., Substantially uniform discharge) are
by adjusting pressures. Alternatively, the gas may beof working gas outlets, decrease of the amount of bubbles, or acquired
guidedfroma plurality of gas tubes to spots of injecting
decrease of both of them. When decreasing the number ofonce by way of a chamber.
working gas outlets, it is preferable to stop outer gas outlets. 10 bubbles
the control according to the present application will
For example, the gas outlets 4041 and 4045 are stopped, or beNext,
described in detail.
the gas outlets 4041 and 4042 and the gas outlets 4045 anddescribed above, according to the present application,
4044 are stopped. Likewise, the inject rates of bubbles are theAspressurizedgas (gas Supply or charged air and Scavenged
controlled in an analogous manner. The inject rates of bubbles gas)/exhaust gas drawing rates are controlled on the basis ofof gas outlets 4041 and 4045 are decreased or increased to the 15 the physical quantities related to the heat load on the main
same degree. Further, the inject rates of bubbles of gas outlet engine and the characteristics of the turbocharger. In this case,4042 and 4044 are decreased or increased to the same degree. as typical examples of physical quantities related to the heatThus, the symmetrical control of the number of substantially load on the main engine, the scavenging gas pressure and thesymmetrically arranged gas outlets with respect to the planar exhaust gas temperature (or exhaust gas pipe temperature,
center line CL of the hull and the inject rates of bubbles can another ambient temperature corresponding to the exhaust
acquire a uniform frictional resistance reduction effect, in a gas temperature in a one-to-one correspondence, etc.) arecase where the vessel is sailing in a straight line, which can adopted. As the characteristics of the turbocharger, the turbo
frequently occur. Accordingly, ability of the vessel to hold a charger efficiency is adopted.
The scavenging gas pressure is detected by the scavenging
straight line can be maintained, and fuel consumption isdecreased. Further, this facilitates the circuit configuration 25 gas pressure sensor S4. The exhaust gas temperature isand the control method of the control device.
detected by the exhaust gas temperature sensor S6.
The comparator 4204 compares a value detected by the
The characteristics of the turbocharger is acquired by (1) adraft sensor 4230 and a condition setting value preliminarily method of acquiring overall efficiency of the turbocharger,
set by the condition setting unit 4220. For example, when the which will be described below, and (2) correction of thewaterline of the hull exceeds the setting value (when the 30 overall efficiency of the turbocharger in a case with the scav
amount of freight is large and the waterline has risen), con enging bypass (exhaust gas bypass).
(1) Method of acquiring overall efficiency of the turbo
trols are performed including increase of the number of work
ing gas outlets, increase of the amount of bubbles or increase chargerof both of them according to the deviation. When the water
Overall efficiency of the turbocharger=0.9055x T/Tx
line has fallen (the freight is unloaded and the vessel is in a 35
(R,0286-1)/(1-R,0265),
condition of ballast water), controls are performed including
wheredecrease of the number of working gas outlets, decrease of the
T: turbocharger air intake temperature (e.g. 21°C.)+273:
amount of bubbles or decrease of both of them. In cases of
T: pre-turbine exhaust gas temperature (e.g. 400° C.)+
decrease, it is preferable to control in an analogous fashion tothat described above.
40 273;
R: (atmospheric pressure+scavenging gas pressure--interWhen swells come, the auxiliary blowers (not shown) and coolerpressure)/(atmospheric pressure-turbo
the bypass adjustment valves 4023A, 4024A and 4025A are chargerdifferential
filter differential pressure); andcontrolled using signals from the draft sensor 4230, and the
R: (atmospheric pressure--post-turbine exhaust gas prespressures acting on the gas outlets 4040 are finely adjusted by Sure)/(atmosphericpressure--exhaust gas receiver pressure).
increasing or decreasing in an immediate manner, thereby 45
Compressor efficiency=3614400xTx(R'?-1)/(xfurther alleviating variation in inject rate of bubbles.
UZ)
The comparator 4204 compares an inclination value of thehull detected by the inclination sensor (not shown) and awherecondition setting value preliminarily set by the condition
L: slip ratio (depending on turbocharger types);setting unit 4220. For example, when the inclination of the 50 D: Vane wheel diameter (depending on turbocharger
hull exceeds the setting value owing to turning or rolling of types); andthe vessel, the inject spots of the working gas outlets are
U: peripheral speed of a gear TLXDxT/Cspeed.
changed or the amount of bubbles is increased or decreased
Turbine efficiency-overall efficiency of the turbocharger/
according to the deviation. For example, if the hull is inclined compressor efficiency.
to the left viewed from a traveling direction, the right side of 55 (2) Correction of overall efficiency of the turbocharger in a
the bottom of the vessel is elevated. In this case, the frictionalcase with Scavenging bypass (exhaust gas bypass)resistance of the hull can effectively be reduced without
The overall efficiency of the turbocharger acquired by (1) is
injecting bubbles in vain by performing controls including multiplied by a correction expression below.
increase of the number of working gas outlets on the left
where an apparent waterline rises, increase of the inject rates 60
where
thereof or increase of both of them and performing controls
including decrease of the number of working gas outlets on
m: mass flow rate passing through the turbine; andthe right, decrease of the inject rates thereof or decrease ofm; equivalent mass to bypass rate passing through theboth of them. The inclination sensor can be shared not only turbine.
for controlling injecting of bubbles but also for adjusting 65 Method of controlling scavenging bypass rate(1) In order to cause the overall efficiency of the turbo
ballast water for detecting the inclination of the hull andmaintaining the balance.
charger to be a required value or more,US 9,376,167 B2
81
82
e.g., for the latest engine, overall efficiency of the turbo that the amount thereof is utilized without deteriorating theperformance and reliability of the engine.
charger 268% or more, andIn order to generate bubbles, it is preferable that pressure bee.g., for retrofit engine, overall efficiency of the turbo
high and temperature behigh. Accordingly, A exhaust bypass
charger c64% or more.
(2) Control is performed such that the scavenging gas pres- 5 gas is most Suitable. However, a problem that the exhaust gas
may directly pollute the ocean is assumed, and it is assumed
Sure becomes at least a prescribed value, and the exhaust gas that
there are unusable waters. In the waters where the exhaust
temperature becomes a prescribed value or less.
gas
bypassbe used, B gas Supply or charged air
Here, the temperature, pressure, and the number of revo bypass gas orgasC cannot
scavengedgas bypass gas may be used. Bandlutions of the turbocharger are the detection values from the 10 Care high pressure air. However,temperature is high,respective sensors. The slip ratio and the vane wheel diameter the Volume is large. Accordingly,ifathepipe
to the gas outlet
are read from the basic data. The processor 4201 calculates should be wide and piping loss should be considered.
thisoverall efficiency of the turbocharger. The corrected value is case, measures, such as thermal insulation and covering,Inmay
acquired by correction by the processor 4201 using the be taken.
exhaust gas/bypass mass flow rate sensors S7 and S9.
15
Since the Scavenging bypass gas has low temperature,
Pressure losses of the filter 4111 and the intercooler 4012,
Small-sized piping can be adopted. A combined configuration
which are necessary to acquire the overall efficiency of the that heats the gas around bubble discharge port by the exhaustturbocharger, are calculated by the processor 4201 on the gas bypass gas can be considered. As described above, thebasis of values from the exhaust gas/bypass mass flow rate bypass piping is raised once at the waterline or higher Suchsensors (S7 and S9) and a pressure loss coefficient stored in 20 that seawater cannot enter the engine 4010. A flowmeter 4035
the basic data unit 4202. Alternatively, instead of the calcu is arranged intermediately at the bypass piping and strictly
lation, pressure sensors (S1 to S9, etc.) are attached to measures the bypass rate.
required spots, and the losses are acquired by detection.
The control of starting/stopping injecting air can be sum
The overall efficiency of the turbocharger can be calculated marized as follows. First, as a principal element of the present
on the basis of a graph or table of turbocharger overall char- 25 application, the bypass gas rate is controlled on the basis ofacteristics preliminarily stored in the basic data unit 4202. In the physical quantity related to the heat load on the main
this case, the load on the main engine 4010 necessary for engine and the characteristics of the turbocharger, and thecalculation is acquired on the basis of the fuel consumption bypass gas is acquired and utilized as bubbles. Next, theoperation of starting/stopping the Supply operation of themeasured by the fuel measurement unit 4320.
In this embodiment, the overall efficiency of the turbo- 30 pressurized gas and/or the exhaust gas from the gas outlet ischarger is acquired by two different methods.
controlled on the basis of the exhaust gas pressure and theMore specifically, the methods include a method of calcu draft of the vessel. Further, the controls include a case pursu
lating by the processor 4201 on the basis of detection values ant to the determination by the vessel conditions determina
from the respective sensors (S1 to S9, 230, etc.), and a method tion unit 4300, a case pursuant to the determination by theof acquiring on the basis of the graph or table. The results are 35 oceanographic condition determination unit 4400 and a casecompared by the comparator 4204. It is determined whether pursuant to the detection result by the navigational condition
both are within a prescribed error range or not. If deviation detection unit (not shown). In the case pursuant to the vessel
from the prescribed error range is detected, a failure in the conditions determination unit 4300, injecting of bubbles issensor is considered. Accordingly, the controller 4205 or a stopped when the GPS 4310 determines that the vessel iswarning unit (not shown) issues a warning.
40 approaching a port or a destination, injecting is started when
The detection value from the oceanographic condition leaving the port, injecting is stopped when the vessel isdetermination unit 4400 and the vessel conditions determina
approaching waters that is a Swirling current region, injecting
tion unit 4300 are used for setting injecting condition of is started when the vessel is leaving the waters; injecting of
bubbles. The details are as described above.
bubbles is stopped when operations of the engines are
The draft sensor 4230 is used for controlling starting/stop- 45 stopped, and injecting of bubbles is started a predeterminedping Supply of gas/exhaust gas to the gas outlets 4040 accord time after the engines start. When the fuel consumption effi
ing to pressurized gas/exhaust gas pressures and the draft. The ciency detected by the fuel measurement unit 4320 becomescondition setting unit 4220 sets the inject condition, the inject below a predetermined one, injecting of bubbles are stopped.
rate and the injecting timing and the like of the gas/exhaust When it is estimated that the fuel consumption efficiency isgas, according to conditions of the oceanographic condition 50 improved, injecting of bubbles is started. When the oceano
determination unit 4400 and the vessel conditions determina
graphic condition determination unit 4400 determines that ittion unit 4300.
is stormy Such as a typhoon and rough weather, injecting of
The turbocharger turbine bypass gas includes three types, bubbles is stopped. When it recovers, injecting is started.
as described below, at the spots of the main body of the Such controls can be performed. The starting/stopping injectengine. The characteristics are as described below.
55 ing bubbles, and the inject rate are controlled in relation to the
A Exhaust bypass gas (the intake is at the exhaust gas operating condition of the main engine. When the main
receiver, temperature: 400° C., pressure: 0.2393 MPa gage engine requires air much, injecting is stopped or the inject ratepressure);is reduced.
B Gas Supply or charged air bypass gas (intake is at the air
Further, when the wave height detected by the wave sensor
Supply pipe (charge air pipe) before intercooler, temperature: 60 4410 becomes a prescribed value or more, injecting of
135°C., pressure: 0.255 MPa gage pressure); andbubbles is stopped; when the wave height becomes a pre
C Scavenged gas bypass gas (intake is at Scavenged gas scribed value or less, injecting is started. The detection resultsreceiver, temperature: 35° C., pressure: 0.2533 MPa gage of the navigational condition detector are compared with apressure).
preset value; on the basis of the deviation, the injecting is
The invention of the present application generates bubbles 65 stopped when the deviation becomes a predetermined thresh
directly from the bypass gas using the bypass gas from each old or less, and the injecting is started when the deviation
spot of the turbocharger or a combination thereof, and secures exceeds the threshold. For example, the values from the rela

US 9,376,167 B2
83
84
tive velocity sensors 55 and 57 are statistically processed and sides of the vessel, and applies image processing to thethe representative value is transmitted to the comparator images and thereby estimates the draft.
4204. When the velocity of the vessel 1 is decreased and the
Eleventh Embodimentvalue becomes lower than a prescribed threshold set by thecondition setting unit 4220, the injecting of bubbles are
FIG. 41 is a diagram showing an overview of a vessel
stopped; when the value exceeds the threshold, the injecting isstarted. On the basis of temporal variation in statistically equipped with a frictional resistance reduction device for aprocessed representative value from the relative velocity sen vessel according to an embodiment of the present invention.
41 (a) is a side view of the vessel. FIG. 41 (b) is a top
sors 55 and 57, when the vessel 1 starts moving and acceler 10 FIG. thereof.
FIG. 41 (c) is a bottom view thereof. A part of aates, the threshold is set to be reduced and bubbles are injected viewprincipal configuration is represented in an exposed manner.
a little earlier. When the frictional resistance reduction effectshown in (a), a inject gas control device is mounted on theis effectively exerted and the vessel is decelerated, the thresh As
vessel
1. The inject gas control device includes a main engine
old may be reset upward and injecting of bubbles may be 10 including
a propulsive engine of the vessel 1.
stopped a little earlier because the speed is decreased and 15 A air supply pipe 5030 is sequentially communicated withbubbles still stay at the bottom 3 of the vessel.
three bypass pipes (the gas Supply or charged air bypass pipe
As to the conditions for starting/stopping injecting gas, 5023, the scavenging bypass pipe 5024 and the exhaust gas
control may be performed according to precedence. When bypass pipe 5025) attached to the main engine 4010. Eachdetection error, failure oran unpredictable event occurs, con bypass pipe includes a bypass adjustment valve. The air Sup
trol may be performed complementarily using another con ply pipe 5030, which includes bent portions, is a pipe fordition. In any event, injecting of bubbles that considers the transferring a gas with a prescribed pressure and temperature
actual frictional resistance reduction effect can be realized by to the gas outlet 5040. The piping is installed from a position
starting/stopping injecting of bubbles under a prescribed con of collecting the three bypass pipes so as to be a shape where
dition, and stopping injecting of bubbles when detecting/ the piping plunges once to a height around the bottom of the
25 vessel, passes the bent portions, is bent toward a height higher
determining that the vessel is stopped.
In the above embodiments, as to the examples of physical than the waterline and laid substantially horizontally, andquantities used for controlling the bypass gas rate, the passes the bent portions and plunges in the direction towarddescription has been made principally with the example of the the bottom of the vessel. The piping path thus passes once at
Scavenging gas pressure and the exhaust gas temperature of 30 a height of the waterline or higher. This can prevent seawaterfrom flowing reversely into the gas outlets arranged on or
the main engine. As to the examples of the physical quantities below
waterline in case of a failure of valves such as a
to be used for controlling operations of starting/stopping the bypassthe
adjustment
and avoid dangerous situations ofSupply operation from the gas outlets of the pressurized gas the main engine invalve,viewof security. The gas outlet 5040.
and/or the exhaust gas, the description has been made princi which is arranged at or in theproximity of the bottom of thepally with the example of the exhaust gas pressure and the 35 vessel and injects gas as bubbles
from an opening perforated
draft of the vessel. These physical quantities are acquired by at or in the proximity of the bottom of the vessel into the water
the sensors. However, physical quantities by another sensor near the bottom 9 of the vessel, is connected to the other end
may be adopted. In the above description, the example adopt of the air supply pipe 5030.
ing turbocharger efficiency as the characteristics of the tur
A residual gas (or a part thereof) of the turbocharger frombocharger has been described. Further, the method of acquir 40 the gas supply or charged air bypass pipe 5023 and/or theing the turbocharger efficiency has also been described above.
Scavenging bypass pipe 5024 and/or the exhaust gas bypass
Instead or in addition thereto, another characteristics (e.g., pipe 5025 passes the air supply pipe 5030 having the bent
matching characteristics between the main engine and the portions, and is guided to the gas outlet 5040 arranged in theturbocharger) can be adopted as the characteristics of the proximity of the bottom of the vessel. For example, in thisturbocharger. Further, in the method of the turbocharger effi 45 embodiment, the gas outlet 5040 is arranged at the fore of theciency, various equations where constants and variables have bottom 9 of the vessel, substantially symmetrically with
been replaced can be adopted instead of the above expression respect to the planar center line of the hull CL. The arrange
ment of the gas outlet 5040 at the bottom 9 of the vessel is forfor calculation.
The above description has been made with the example of 50 the purpose of prolonging the retention of the injected
injecting the gas (air) bypassed from the turbocharger directly bubbles at the bottom 9 of the vessel and alleviating influ
owing to waves. The arrangement at the fore in theinto the water as bubbles. Instead, it may be configured such ences
proximity
the bottom of the vessel is for an object forthat the turbine drives an electric generator, a blower (gas retaining theofinjected
gas over the entire bottom 9 of the vessel
Supply or charged air means) is separately driven using the as much as possible. In
cases where these purpose and object
electric power gained by the electric power generation, and 55 are not necessary, the gas
outlet 5040 may be at a spot otherbubbles generated by the blower is discharged from the than the bottom 9 of the vessel.
The spot may be an appropri
nozzle 4040. Alternatively, turbine may be equipped with, for ate one on or below the waterline. Particularly, in a case ofexample, a coaxially driven mechanism, the blower (gas Sup arrangement of the gas outlet 5040 at the bottom 9 of theply or charged air means) may be driven directly, and bubbles vessel, it can be expected that the retention of bubbles become
may be generated therefrom.
60 longer. Further, the bubbles with a diameter of at least a
To grasp and sense the draft, for example, a method may be several hundred um, exerts a buoyant effect. Accordingly, an
adopted that uses sensors for measuring and detecting pres effect that bubbles adhere to the bottom of the vessel is also
sure below the waterline at the bottom of the vessel and the
expected. When the supply of the pressurized gas and/or thesides of the vessel and thereby grasps the draft from a pro exhaust gas is stopped, a blocking valve 5027 is provided
portional relationship between pressure and depth. Further, 65 immediately before the gas outlet 5040 in order to preventfor example, a method may be adopted that takes images of water from entering the air supply pipe 5030. Since the block
situations around the Surface of water by cameras from the ing valve 5027 is provided, the air supply pipe 5030 is resis

US 9,376,167 B2
85
86
need
not
be
plural.
One
endplate may be provided on thetant to influences of entry of water. Accordingly, as to material
and thickness, it is unnecessary to consider high anti-corro longitudinal direction of the bottom of the vessel.
A draft sensor 5230 is provided at a spot without influences
siveness and pressure-tightness. To stop the gas Supply or
charged air, it is preferable to preliminarily close the blocking of waves and bubbles in the water at the stern. A relative
valve 5027 under the gas pressure. To start the gas supply or velocity sensor 55 is provided at a spot without influences ofcharged air, it is preferable to open this valve after the gas waves and bubbles of the bow. A depth sounder 5060 isprovided at a spot without influences of waves and bubbles inpressure has risen at least to a prescribed value.
Thus, entry of water can be reliably blocked, thereby pre the water at the bow. The depth sounder 5060 performs sonicSounding that emits ultrasonic waves from a side of the vessel
venting entry of water into air supply pipe 5030 and occur 10 andacquires a depth from a time period until the ultrasonicrence of backflow. This can prevent the air supply pipe 5030 waves
reflected by the sea bottom and return. It is preferablefrom being damaged. More specifically, this can prevent the to dispose
depth sounder 5060 at an appropriate spot
formation of rust in the air supply pipe 5030 owing to water, resistant to the
influences of waves and bubbles so as not to
obviate fouling of marine organisms, Suppress increase in receive influences on transmission and reception of the ultra
frictional resistance when gas is injected, alleviate mainte 15 Sonic waves. Even in a case of providing a type of sensor innance, and in turn allow long-term use of the air supply pipe the water as the relative velocity sensor 55, it is preferable to
30. It is preferable that the air supply pipe 5030 adopt a provide the sensor at a spot without influences of waves andmaterial resistant to seawater or Surface coating be applied bubbles.
thereto. Since the air supply pipe 5030 is closed by the block
In addition thereto, a shear force sensor 5240, which
ing valve 5027, increase infrictional resistance owing to entry detects a share force exerted on the hull owing to seawater andofflowing water into the air supply pipe 5030 while the vessel bubbles, is arranged on the bottom 9 of the vessel, for example
is sailing can be suppressed. The operation of the blocking at the stern.
The flow rate sensor S7 detects gas supply or charged air
valve 5027 is pursuant to automatic control of opening andclosing the valve, depending on presence or absence of the rate at the air supply pipe 5030, and monitors whether anelectric power or pressurized gas. However, under certain 25 appropriate gas rate of gas is transferred or not.
A system for bypassing the pressurized gas and the exhaust
conditions, the control may be pursuant to manual operation
gas from the turbocharger will be described using FIG. 37 ofof opening and closing the valve, or semiautomatic control.
In this embodiment, the gas Supply or charged air is the tenth embodiment.
The turbocharger 4011 includes a compressor 4110 that
stopped before the main engine is stopped. The method of
stopping includes preliminarily stopping the blocking valve 30 draws atmosphere through a filter 4111 and compresses the5027 and then closing the bypass valve, and subsequently air, a turbine 4112 rotationally drives the compressor 4110,
stopping the main engine and the turbocharger. Starting is and a shaft connecting these. According to the mechanism of
performed inversely. This can exert an advantageous effect the turbocharger 4011, energy of the exhaust gas (temperature
specific to the present application that is capable of reliably and pressure) having been discharged from the main engine ispreventing water from entering the air supply pipe 5030 and 35 utilized. The turbine 4112 is driven and rotates at high speeds.
the main engine 4010.
The compressor 4110 is driven by this rotational force. The
When the main engine load becomes below a prescribed compressed air is transferred into the cylinders 4016 of thevalue (e.g. 50%), the gas Supply or charged air is stopped. main engine (hereinafter, also referred to as the “cylinder for
More specifically, the supply is stopped with an allowance for the sake of the simplicity). Accordingly, an amount of mixture
turbocharger efficiency required by the main engine. When 40 over an amount of original aspiration of an internal combus
the value exceeds the prescribed value, the gas Supply or tion engine is aspirated and combusted, thereby acquiring an
charged air is started. This can exert an advantageous effect output over an apparent piston displacement.
High temperature and pressure exhaust gas generated by
specific to the present application that is capable of Supplying
without dropping below the gas rate required by the main combustion of fuel in each cylinder 4016 is accumulated inengine.
45 the exhaust gas receiver 4015 during the exhaust gas valve is
The gas outlets 5040 are arranged in the planar configura opened. The pressure is caused to be static. Adiabatic expan
tion such that the plurality thereof are arranged substantially sion is accomplished at the turbine nozzle 4116 (the broken
symmetrically with respect to the planar center line CL. The line part) and the turbine 4112. This generates turbine driving
air supply pipes 5030 may be provided as many as the gas force, and rotates the compressor 4110 directly connected
outlets 5040. Instead, branched pipes from the air supply pipe 50 thereto. The compressor 4110 draws air from the outside, and5030 are provided as many as the corresponding number. This applies adiabatic compression. The air is caused to be staticallows the configuration to be simplified and can facilitate the pressure at a diffuser 4113 at an outlet of the compressor
arrangement. Preferably, the number of the discharge ports is 4110. This generates high pressure and temperature air (gasan odd number, and a symmetric arrangement is adopted Supply or charged air). The air is cooled by an intercooler
where the center one is disposed on the planar center line CL. 55 4012, accumulated in the scavenged gas receiver 4014, andPreferably, also for the gas outlets 5040, the diffusion supplied to the cylinder 4016. In cases where the load on thelimiting sections are disposed Substantially symmetrical with main engine 4010 is low and the energy of the exhaust gas isrespect to the planar center line of the hull CL. More specifi insufficient, such as a case immediately after startup, an aux
cally, as shown in (c), endplates 5095,5096 and 5097 limiting iliary blower 4115 is actuated, draws air and supports the
diffusion of the gas injected as bubbles from the gas outlets 60 operation of the turbocharger compressor 4110. In this con
5040 are arranged, and end plates 5095a, 5096a and 5097a figuration, according to the present application, the gas Sup
are arranged symmetrically with respect to the planar center ply or charged air bypass pipe 4023, the scavenging bypass
line CL. The end plates 5096, 5096a, 5097 and 5097a are pipe 4024 and the exhaust gas bypass pipe 4025 are provided
illustrated so as to be in the same dimensions in this figure. and bypass the residual gas.
However, the end plates 5097 and 5097a may have smaller 65 In more detailed operation, first, atmosphere is drawn
dimensions than those of the end plates 5096 and 5096a. The through the filter 4111. Compressed air is generated by the
number of end plates is not limited to that of the figure, and compressor 4110 driven by the rotational force of the turbineUS 9,376,167 B2
87884112, and communicated to the air supply pipe 4013 via the nozzle 4118 is capable of controlling the inflow condition ofdiffuser 4113. The gas supply or charged air bypass pipe 4023 the exhaust gas that flows into the turbine 4112 of the turbo
is communicated with the air supply pipe 4013, as described charger 4011. Accordingly, the turbine 4112 is driven in aabove. A part of the compressed high temperature air passes preferable manner.
through the gas Supply or charged air bypass pipe 4023 and
FIG. 42 is an enlarged view principally showing a variablethus is bypassed. The draw of gas by this bypass is performed nozzle according to an embodiment of the present invention.
by opening and closing the gas Supply or charged air bypass As shown in this figure, the variable nozzle 5118 includes anadjustment valve 4023A, whose starting and stopping is con arc-shaped casing 5150 and a wing-shaped vane 5151 (thetrolled on the basis of sensing of after-mentioned physical number thereof is not limited.). The vane 5151 has a shapequantities. The gas Supply or charged air acquired through the 10 that optimizes the fluid path of gas. It is preferable to mini
bypass by the gas Supply or charged air bypass pipe 4023 is mize resistance. This is because the angle of the vane 5151 isguided to the air supply pipe 4030.
changed to control Such that the exhaust gas concentratedly
The other airpassing the air supply pipe 4013 is intercooled flows onto the turbine 4112. The material and the dimensions
by the intercooler 4012. The intercooled compressed air is thereof are not limited, but preferably are what has anti
dehydrated by the mist catcher 4114 disposed in the commu 15 corrosiveness against the exhaust gas and prevents included
nication pipe, passes through a movable gate, and communi matter of the exhaust gas such as soot from accumulating andcated to the Scavenged gas receiver 4014. The gas may be depositing.
Supplied to the Scavenged gas receiver 4014 also from the
FIG. 42 (a) shows the variable nozzle 5118 in a state with
auxiliary blower 4115 including an adjustment valve 4115A.
Small opening and (b) shows that in a state with large opening.
The scavenging gas bypass pipe 4024 is communicated with In (a), because spaces formed between the vanes 5151 are
the Scavenged gas receiver 414, as described above. A part of Small, the fluid path of the exhaust gas is narrowed. Accord
the compressed air accumulated in the Scavenged gas receiver ingly, when the inflow rate of the exhaust gas flowing therein4014 passes through the scavenging bypass pipe 4024 and is Small, the exhaust gas passes through the variable nozzle
thus is bypassed. The draw of gas by this scavenging bypass 5118 in the narrowed state. This can cause the exhaust gas tois performed by opening and closing the scavenging bypass 25 collide with the turbine 4112 in a concentrated manner. On
adjustment valve 4024A, whose starting and stopping is con the other hand, in (b), because spaces formed between thetrolled on the basis of sensing of after-mentioned physical vanes 5151 are large, the fluid path of the exhaust gas isquantities. The gas Supply or charged air acquired through the secured in a state where the pressure loss is Small.
bypass by the Scavenging bypass pipe 4024 is guided to the air
FIG. 43 is a characteristics diagram showing an example of
30 relationship between a main engine load and an efficiency of
supply pipe 4030.
The other air accumulated in the scavenged gas receiver a turbocharger according to presence or absence of a variable
4014 passes through the communication pipe, and is guided nozzle according to an embodiment of the present invention.
to the cylinder 4016. In the cylinder 4016, fuel is injected As shown in this figure, a case without the variable nozzles
thereinto and combusted. The exhaust gas generated by the 5118 is represented by the solid line, and a case with these
combustion is guided to exhaust gas receiver 4015. The 35 nozzles is represented by the broken line.
exhaust gas bypass pipe 4025 is communicated with the
In the case represented by the solid line, a considerable
exhaust gas receiver 4015, as described above. A part of the Surplus is actually generated with respect to the desired value
exhaust gas accumulated in the exhaust gas receiver 4015 of the main engine efficiency. For example, with 75.0% main
passes through the exhaust gas bypass pipe 4025 and thus is engine load, 72.7% efficiency can be acquired in actuality
bypassed. The draw of gas by this exhaust gas bypass is 40 while the desired value of the main engine efficiency is
performed by opening and closing the exhaust gas bypass 68.0%. This difference is available as residual gas. Accord
adjustment valve 4025A, whose starting and stopping is con ingly, attention is given the fact that the thus generated gas hastrolled on the basis of sensing of after-mentioned physical originally been discharged in vain. A concept of the frictional
quantities. The gas Supply or charged air acquired through the resistance reduction device of the present embodiment is to
bypass by the exhaust gas bypass pipe 4025 is guided to the air 45 effectively utilize this. On the other hand, in the case where
supply pipe 30.
the variable nozzle 5118 is included and representation is
The other exhaust gas in the exhaust gas receiver 4015 is made by the broken line, with 75.0% main engine load, highguided to the turbine 4112 via the turbine nozzle 4116 having efficiency of 73.8% is realized while the desired value of thea narrow diameter. A part of this gas rotationally drives the main engine efficiency is 68.0%. Even if the load on the main
turbine 4112, and communicated to the chimney (not shown) 50 engine varies, the efficiency of the turbocharger 4011 isas the exhaust gas to be discharged.
totally high, in comparison with a case without the variable
On the other hand, the exhaust gas rate or the pressure nozzle 5118. According to these, the control of the variablebypassed by the exhaust gas bypass pipe 4025 occasionally nozzle 5118 optimizes the fluid path. Thus, the effect exertedvary according to control of opening and closing the exhaust by controlling the inflow condition of the exhaust gas flowing
gas bypass adjustment valve 4025A based on sensing of 55 into the turbine 4112 can be confirmed. The control of thephysical quantities. This causes a difference in inflow rate of variable nozzle 5118 adjusts the area of the path of the gas andthe exhaust gas guided into the turbine 4112. The turbine the fluid path so as not to decrease the turbocharger efficiency
4112 rotates by the energy of the inflow exhaust gas. Airflows owing to variation in inflow gas condition, thereby allowing
thereinto by the compressor 4110 directly connected to the the gas to be preferably supplied to the exhaust gas turbine.
turbine 4112, and pressurized to a high pressure and blown 60 In the present application, the normal operation point of theinto the cylinder 4016. Accordingly, the main engine effi main engine is disposed lower than a position Substantiallyciency is dependent on driving efficiency of the turbine 4112, adjacent to the main engine load, which corresponds to thei.e. the exhaust gas rate or pressure of the exhaust gas to be peak of the characteristics of the turbocharger (as shown indrawn. Above all, the main engine efficiency also varies FIG. 43, the normal operation point of the main engine load is
65 75%, the peak without the variable nozzle is 76%, and theaccording to load conditions of the main engine 4010.
In this embodiment, a variable nozzle 4118 capable of peak with the variable nozzle is 82%). The same is true in achanging the turbine nozzle 4116 is attached. The variable case with the variable nozzle. According to this, an advanta