(12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)(19) World Intellectual Property Organization
International Bureau

11111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111(10) International Publication Number(43) International Publication Date

22 September 2011 (22.09.2011)

PCT(51) International Patent Classification:
F02B 33122 (2006.01)(21) International Application Number:
PCT/US20ll/028276(22) International Filing Date:(25) Filing Language:

Sussex BN43 6RB (GB). BADAIN, Nicholas [GB/GB];
37 Rosslyn Road, Shoreham-by-Sea, West Sussex BN43
6WL (GB). GILBERT, Ian [GB/GB]; 67 Beach Green,
Shoreham-by-Sea, West Sussex BN43 5YE (GB).

(74) Agents: FILDES, Christopher, J. et al.; Fildes & Outland, P.C., 20916 Mark Avenue, Suite 2, Grosse Pointe
14 March 2011 (14.03.2011)
Woods, MI 48236 (US).
English (8 l) Designated States (unless otherwise indicated, for every(26) Publication Language:(30) Priority Data:
61/313,831
61/363,825
61/365,343

WO 2011/115868 A1

15 March 2010 (15.03.2010)13 July2010 (13.07.2010)18 July2010 (18.07.2010)

Englishususus(71) Applicant (for all designated States except US): SCUDERI GROUP, LLC [US/US]; llll Elm Street, Suite 33,
West Springfield, MA 01089 (US).

kind of national protection available): AE, AG, AL, AM,
AO, AT, AU, AZ, BA, BB, BG, BH, BR, BW, BY, BZ,
CA, CH, CL, CN, CO, CR, CU, CZ, DE, DK, DM, DO,
DZ, EC, EE, EG, ES, FI, GB, GD, GE, GH, GM, GT,
HN, HR, HU, ID, IL, IN, IS, JP, KE, KG, KM, KN, KP,
KR, KZ, LA, LC, LK, LR, LS, LT, LU, LY, MA, MD,
ME, MG, MK, MN, MW, MX, MY, MZ, NA, NG, NI,
NO, NZ, OM, PE, PG, PH, PL, PT, RO, RS, RU, SC, SD,
SE, SG, SK, SL, SM, ST, SV, SY, TH, TJ, TM, TN, TR,
TT, TZ, VA, UG, US, UZ, VC, VN, ZA, ZM, ZW.

(72) Inventors; and(75) Inventors/Applicants (for US only): MELDOLESI, Ric- (84) Designated States (unless otherwise indicated, for every
cardo [IT/GB]; 55 New Road, Shoreham-by-Sea, Westkind of regional protection available): ARIPO (BW, GH,[Continued on next page]::: -----------------------------------------------------------------------------------------(54) Title: SPLIT -CYCLE AIR-HYBRID ENGINE WITH AIR EXPANDER AND FIRING MODE--;;;;;;;;;;;;;;;--;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

FIG. 1(57) Abstract: A split-cycle air hybrid engine includes a rotatablecrankshaft. A compression piston is slidably received within a compression cylinder and operatively connected to the crankshaft. An expansion piston is slidably received within an expansion cylinder andoperatively connected to the crankshaft. A crossover passage interconnects the compression and expansion cylinders. The crossover passage
includes a crossover compression (XovrC) valve and a crossover expansion (XovrE) valve defining a pressure chamber therebetween. An
air reservoir is operatively connected to the crossover passage. An air
reservoir valve selectively controls air flow into and out of the air reservoir. In an Air Expander and Firing (AEF) mode of the engine, the engine has a residual expansion ratio at XovrE valve closing of 15.7 to I
or greater, and more preferably in the range of 15.7 to I and 40.8 to I.

W 0 2011/115868 A1 11111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111
GM, KE, LR, LS, MW, MZ, NA, SD, SL, SZ, TZ, UG,
ZM, ZW), Eurasian (AM, AZ, BY, KG, KZ, MD, RU, TJ,
TM), European (AL, AT, BE, BG, CH, CY, CZ, DE, DK,
EE, ES, FI, FR, GB, GR, HR, HU, IE, IS, IT, LT, LU,
LV, MC, MK, MT, NL, NO, PL, PT, RO, RS, SE, SI, SK,

SM, TR), OAPI (BF, BJ, CF, CG, CI, CM, GA, GN, GQ,
GW, ML, MR, NE, SN, TD, TG).
Published:-with international search report (Art. 21(3))

wo 2011/115868

PCT/US2011/028276

1

SPLIT-CYCLE AIR-HYBRID ENGINE WITH AIR EXPANDER AND FIRINGMODE

TECHNICAL FIELD

This invention relates to split-cycle engines and,more particularly,
5

tosuch anengineincorporating an

airhybrid system.

BACKGROUND OF THE INVENTION

For
10engine"aspurposes

used

in

of

the

clarity,present

theterm"conventional

applicationreferstoaninternal combustion engine wherein all four strokes of thewell-known

Otto

cycle

compression,

expansion(i.e.,

the(or power)

intake(orinlet) ,and exhaust strokes)

arecontained in each piston/cylinder combination of the engine.
15

Each stroke requires

one half revolution of the crankshaft(180 degrees crank angle
the crankshaft(CA)),and two full revolutions of(720 degrees CA) are required to complete theentire Otto cycle in each cylinder of a conventional engine.
Also,
20

for

purposesofclarity,thefollowing

definition is offered for the term "split-cycle engine" as
may be applied to engines disclosed in the prior art and as
referred to in the present application.
A

split-cycle

engineasreferredtohereincomprises:25

a crankshaft rotatable about a crankshaft axis;acompression
crankshaft

compression
cylinder
such

that

pistonslidablyreceived

withinandoperatively

connected

tothecompression

pistonathe

reciprocatesthrough an intake stroke and a compression stroke during a30

single rotation of the crankshaft;wo 2011/115868

PCT/US2011/028276

2

anwithinexpansionan expansion(power)cylinderpistonslidablyreceived

and operatively connected tothe crankshaft such that the expansion piston reciprocatesthrough an expansion stroke and an exhaust stroke during a5single rotation of the crankshaft; andacrossoverpassage(port)

compression and expansion cylinders,
including

at

least

a

crossoverinterconnecting

thethe crossover passage

expansion(XovrE)

valve

disposed therein, but more preferably including a crossover
10compression(XovrC)valve and a crossover expansion(XovrE)valve defining a pressure chamber therebetween.
United States
8,6,543,225 granted April

2003 to Scuderi and United States

granted October 11,
15

Patent No.

Patent No.

2005 to Branyon et al.,are incorporated herein by reference,
discussion
addition,ofsplit-cycle

and6, 952,923

both of whichcontain an extensive

similar-type

engines.

In

these patents disclose details of prior versionsof an engine of which the present disclosure details further
developments.
20

Split-cycle
cycle

enginewithanair-hybrid
airengines

reservoir

combineand variousasplit-

controls.

This combination enables a split-cycle air-hybrid engine to
store

energyreservoir.
25

in

the

form

of

compressed

air

in

the

air

The compressed air in the air reservoir is later

used in the expansion cylinder to power the crankshaft.
A split-cycle

air-hybrid

engineasreferredtoherein comprises:
a crankshaft rotatable about a crankshaft axis;
a30

compression
crankshaft

compression
cylinder
such

that

pistonslidablyandoperatively

thecompression

received withinconnected

pistontoathe

reciprocatesthrough an intake stroke and a compression stroke during asingle rotation of the crankshaft;wo 2011/115868

PCT/US2011/028276

3

anwithinexpansionan expansion(power)cylinderpistonslidablyreceived

and operatively connected tothe crankshaft such that the expansion piston reciprocatesthrough an expansion stroke and an exhaust stroke during a5single rotation of the crankshaft;acrossoverpassage(port)

compression and expansion cylinders,
including

at

least

a

crossoverinterconnecting

thethe crossover passage

expansion(XovrE)

valve

disposed therein, but more preferably including a crossover
10compression(XovrC)valve and a crossover expansion(XovrE)valve defining a pressure chamber therebetween; andancrossoverairreservoir

passageandoperatively

selectively

connected

operable

to

to

the
store

compressed air from the compression cylinder and to deliver
15

compressed air to the expansion cylinder.
United States
8,

20

Patent No.

2 0 0 8 to Scuderi et al.,7,353,786 granted April

which is incorporated herein byreference,contains an extensive discussion of split-cycle

air-hybrid

andsimilar-type

patent discloses details

engines.

In

addition,of prior hybrid systems

thisof whichthe present disclosure details further developments.
A split-cycle air-hybrid engine can benormal operating or firing
the25

Enginemodes.

Firing(EF)

In the EF mode,

mode)

reservoir.

connecting

mode
and

(also commonly called
four

basic

air-hybrid

operating without the use of its

In the EF mode,

the

in a

the engine functions as a non-air

hybrid split-cycle engine,
air

(NF)

run

crossoverpassageatank valve operatively
to

the

air

reservoir

remains closed to isolate the air reservoir from the basic
30

split-cycle engine.
The

split-cycle

air-hybrid

engineoperates

the use of its air reservoir in four hybrid modes.
hybrid modes are:with

The fourwo 2011/115868

PCT/US2011/028276

4

Air

1)

Expandercompressed

(AE)

air

mode,

energy

which

from

includes

the

air

using

reservoir

without combustion;
2)
5

Air Compressor(AC)compressedenergyairmode,which includes

into

the

air

storing

reservoir

without combustion;
3)

Air Expander and Firing (AEF) mode, which includes
using compressed air energy from the air reservoir
with combustion; and10

4)Firingandstoring

Charging

compressed

(FC)
air

mode,

which

includesenergy

into

the

air

AE,

AC,

reservoir with combustion.
However,further

AEF and FC,
15

optimization of these modes,EF,

is desirable to enhance efficiency and reduce

emissions.

SUMMARY OF THE INVENTION

The present invention provides a split-cycle air20

hybridengineFiring

(AEF)

in

which

the

use

of

the

Air

Expanderandmode is optimized for potentially any vehicle

in any drive cycle for improved efficiency.
Moreparticularly,

anexemplaryembodimentofasplit-cycle air-hybrid engine in accordance with the present
25

invention includes a crankshaft rotatable about a crankshaft
axis.

A compression piston iscompression
crankshaft

cylinder
such

that

slidably received within aandoperatively

thecompression

connected
pistontothereciprocatesthrough an intake stroke and a compression stroke during a30

single rotation of the crankshaft.
slidablyreceived

operatively
expansion

withinconnected

pistonto

An expansion piston isanexpansionthecrankshaft

reciprocatesthroughancylinder
such

that

expansionandthestrokewo 2011/115868

PCT/US2011/028276

5

and

an

exhaustcrankshaft.

5

strokeAduringacrossoversinglepassagerotationoftheinterconnects

thecompression and expansion cylinders.

The crossover passage

includes(XovrC)acrossovercompression

crossover

expansion(XovrE)

chamber

therebetween.

An

valve
air

valve

and

a

pressuredefining

reservoirisaoperatively

connected to the crossover passage and selectively operable
to store compressed air from the compression cylinder and todeliver
10compressed air

theexpansion

cylinder.

An

airreservoir valve selectively controls

air flow into and out

of

is

the

air

reservoir.

Expander and Firinghasaresidual

15. 7 to
15

to

The

engine(AEF) mode.

expansion

1 or greater,

ratio

operable

in

an

Air

In the AEF mode,the engine

atclosing

XovrE

valve

and more preferably in the

of

range

of

15.7 to 1 and 40.8 to 1.
A

methodofoperatingengine is also disclosed.

asplit-cycle

air-hybrid

The split-cycle air-hybrid engine

includes a crankshaft rotatable about a crankshaft axis.

A

compression piston is slidably received within a compression
20

cylinder

and

that

compression piston reciprocatestheoperatively

connected

tothecrankshaft

through ansuchintakestroke and a compression stroke during a single rotation ofthecrankshaft.

within
25

the

an

An

expansion

crankshaft

expansion piston
cylindersuch thatandisslidably received

operatively

connected

tothe expansion piston reciprocatesthrough an expansion stroke and an exhaust stroke during asinglerotationofthecrankshaft.

Acrossoverpassageinterconnects the compression and expansion cylinders.
crossover passage
30

valve

and

pressureaincludescrossoverchamberacrossover

expansion

therebetween.

operatively

connected

selectively

operabletotocompression(XovrE)
An

valve
air

the

crossoverstore

compressed

The(XovrC)

definingareservoirispassage

and

air

from

the

wo 2011/115868

PCT/US2011/028276

6
compression cylinder and to
expansion

cylinder.

An

deliveraircompressed air

reservoir

valve

to

the

selectively

controls air flow into and out of the air reservoir.

The

engine is operable in an Air Expander and Firing (AEF) mode.
5

The method in accordance with the present invention includes
the10

following

steps:

openingtheadmittingcompressed

air

from

the

expansion

cylinder

with

fuel,

at

expansion

stroke,theexpanded

on

the

same

piston,transmitting

fuel

air
air

reservoir

the

being

stroke

power

the

of

valve;

into

beginning

ignited,expansiontoreservoir

the

of

an

burnedandtheexpansion

crankshaft,

and

the

combustion products being discharged on the exhaust stroke;and maintaining a

residual

expansion

closing of 15.7 to 1 or greater,
15

ratio

at XovrE valve

and more preferably in therange of 15. 7 to 1 and 4 0. 8 to 1.
These

and

other

invention will be morefeaturesandadvantages

fully understood from the

of

the

followingdetailed description of the invention taken together with theaccompanying drawings.
20
BRIEF DESCRIPTION OF THE DRAWINGSIn the drawings:
FIG. 1 is a lateral sectional view of an exemplary
25

split-cycle air-hybrid engine in accordance with the present
invention;
FIG.

2 is a graphical illustration of a preferred

exemplary range of residual expansion ratio
volumetric30

crossover

expansion
expansionpresent invention;

ratio)(XovrE)

versusvalve

in(i.e.,

closing

effective

angle

accordance

of

with

a
the

wo 2011/115868

PCT/US2011/028276

7FIG.

3 is a graphical illustration of XovrE valve

closing timing with respect to tank pressure and load at anengine speed of 1000 revolutions per minute (rpm);
FIG.
5

4 is

a graphical illustration of XovrE valve

closing timing with respect to tank pressure and load at anengine speed of 1500 rpm;
FIG.

5 is a graphical illustration of XovrE valve

closing timing with respect to tank pressure and load at anengine speed of 2000 rpm;
10

FIG.

6

is a graphical illustration of XovrE valve

closing timing with respect to tank pressure and load at anengine speed of 2500 rpm;
FIG.

7

is a graphical illustration of XovrE valve

closing timing with respect to tank pressure and load at an
15

engine speed of 3000 rpm; andFIG.

8 is a graphicalillustration of XovrE valve

closing timing with respect to tank pressure and load at anengine speed of 3500 rpm.

DETAILED DESCRIPTION OF THE INVENTION

20

The following glossary of acronyms and definitionsof terms used herein is provided for reference.
In General
25

Unless otherwise specified,closing timings

are measured inall valve opening andcrank angle

degrees

after

top dead center of the expansion piston (ATDCe) .
Unlessotherwise

are in crank angle degrees
30

Air tank

specified,

all

valve

durations(CA) .

(or air storage tank) : Storage tank for compressed

air.
ATDCe: After top dead center of the expansion piston.
Bar: Unit of pressure, 1 bar=

10 5 N/m 2

wo 2011/115868

PCT/US2011/028276

8

5

BMEP:

Brake

referstotheoutputas

outputshaft),

after

frictionfor.

Brake Mean Effective Pressure

effective

pressure.

delivered

The

to

the

lossesterm

crankshaft(FMEP)(BMEP)"Brake"are(oraccounted

is the engine's

brake torque output expressed in terms of a mean effective
pressure(MEP)

value.

BMEP

is equal

divided by engine

displacement.

parameter

after

taken

Accordingly,
10

mean

to

This

the

losses

BMEP=IMEP-friction.

the brakeistheperformance

due

to

friction.

Friction,

usually also expressed in terms

torquein this case isof an MEP value

known

as

Frictional Mean Effective Pressure (or FMEP)
Compressor:

The

compression

cylinderandits

associatedits

associatedcompression piston of a split-cycle engine.
Expander:15

The

expansion

cylinderandexpansion piston of a split-cycle engine.
IMEP:

Indica ted

Mean

Effective

Pressure.

The

term

"Indicated" refers to the output as delivered to the top of
the piston, before friction losses (FMEP) are accounted for.
RPM: Revolutions Per Minute.
20

Tank

valve:

Valve

connecting

the

Xovr

passagewith

thecompressed air storage tank.
VVA:

Variable

operable

to

valve

alter

actuation.

A

shape

timingtheormechanism
of

a

or

methodvalve's

lift

profile.
25

Xovr

(or

Xover)

valve,

passage

or

port:

The

crossovervalves, passages, and/or ports which connect the compression
andexpansion

cylindersthrough

which

gas

flows

from

compression to expansion cylinder.
XovrC
30

(or XoverC)

valves:Valves at

the compressor end of

the Xovr passage.
XovrE(or XoverE) valves: Valves at the expander end of thecrossover (Xovr) passage.

wo 2011/115868

PCT/US2011/028276

9

Referring to FIG. 1, an exemplary split-cycle airhybrid engine is shown generally by numeral 10.

The split-

cycle air-hybrid engine 10 replaces two adjacent cylindersof5aconventional

enginewithacombinationofcompression cylinder 12 and one expansion cylinder 14.

oneAcylinder head 33 is typically disposed over an open end of
the expansion and compression cylinders 12,

14 to cover andseal the cylinders.
The
10

four

strokes

of

the

Otto

cycle

are

"split"over the two cylinders 12 and 14 such that the compression
cylinder 12, together with its associated compression piston
20,

15

performtheintakeandpistonstrokes.

The Otto cycle is therefore completed in these twocylinders

12,

once

per

the

its

the

expansion

performwithandcylinder30,

togetherstrokes,

expansion

14

14,

compression

expansion

crankshaft

16

associatedandexhaustrevolution(360

degrees CA) about crankshaft axis 17.
During the intake stroke, intake air is drawn into
the20

compression

disposedinthecylinder12throughcylinder

head

33.

an

intake

port

19

An

inwardly

opening(opening inwardly into the cylinder and toward the piston)poppet intake valve 18 controls fluid communication between
the intake port 19 and the compression cylinder 12.
During25

piston20

chargeinto

thepressurizes
thecompression
the

air

stroke,chargecrossover passage

and

the

drives(or port)

typically disposed in the cylinder head 33.

compression

22,

the

air

which

is

This means thatthe compression cylinder 12 and compression piston 20 are asource30ofhigh-pressure

gas

to

the

crossoverpassage22,

which acts as the intake passage for the expansion cylinder
14.

In some embodiments,

two or more crossover passages 22

interconnect the compression cylinder 12 and the expansion
cylinder 14.

wo 2011/115868

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10

The geometric (or volumetric) compression ratio ofthecompression cylinder 12of split-cycle engine

10

for

split-cycle

general)commonlyreferred to5

engine.

asengines
the

in

is

"compression ratio"

The geometric(or volumetric)

hereinof thesplit-cycle

compression ratio of

the expansion cylinder 14 of split-cycle engine 10
split-cycle engines in general)(and(and foris herein commonly referred

to as the "expansion ratio" of the split-cycle engine.

The

geometric compression ratio of a cylinder is well known in
10

the art as the ratio of the enclosed (or trapped) volume inthecylinderreciprocating

15(including
therein

is

all
at

recesses)

its

when

bottom deadapistoncenter(BDC)

position to the enclosed volume(i.e.,

clearance volume)thesaid piston

is

at

its

Specificallyfor

split-cycle

cylinder

(TDC)

when

position.

definedherein,thecompression

ratio

top

of

dead

centerenginesainascompression

cylinder is determined when the XovrC valve is closed.

Also

specifically for split-cycle engines as defined herein,

theexpansion ratio of an expansion cylinder is determined when20

the XovrE valve is closed.
Due to very high compression ratios
1,

25

1,

40

to

greater)withinthecylinder12,anoutwardly opening(opening

outwardly away

from

the

cylinder)

valve

24

at

the

flow

from

controlcrossover passage(e.g.,

20 to 1,

or

20 to

to

30

1,

(e.g.,

poppetcrossovercrossoverthe22.

passagecompression
Due

30 to 1,

to40

compression

compression
inlet(XovrC)

25

is

used

to

cylinder

12

into

the

very high expansion

to 1,

or greater)

ratioswithin the

expansion cylinder 14, an outwardly opening poppet crossover
30

expansion (XovrE) valve 26 at the outlet 27 of the crossover
passage 22 controls flow from the crossover passage 22 into
the expansion cylinder 14.

The actuation rates and phasingof the XovrC and XovrE valves 24,

26 are timed to maintainwo 2011/115868

PCT/US2011/028276

11

pressure

inthecrossoverpassage

22

at

a

high

minimumpressure(typically 20 bar or higher at full

load)

duringall four strokes of the Otto cycle.
At5

least onefuelinjector 2 8 injects

fuel

into

the pressurized air at the exit end of the crossover passage
22 in correspondence with the XovrE valve 26 opening, which
occursshortly before expansion piston 30

deadcenterposition.

The

air/fuel

reacheschargeits

topenterstheexpansion cylinder 14 when expansion piston 30 is close to
10

its

top

dead

centerposition.

descent

fromits

dead center position,

top

XovrE valve 26 is still open,aspark plug

tip

39

that

As

piston30

beginsits

and whilethespark plug 32, which includes

protrudes

intocylinder14,isfired to initiate combustion in the region around the spark
15

plug

tip

39.

Combustion

can

be

initiated

while

the

expansion piston is between 1 and 30 degrees CA past its top
dead center (TDC) position.

More preferably, combustion canbe initiated while the expansion piston is between 5 and 25
degrees CA past its top dead center
20

preferably,(TDC)

initiated
such
25

as

position.

Most

combustion can be initiated while the expansion

piston is between 10
center(TDC)

and 2 0 degrees

position.

throughwithAdditionally,

other

glow

CA pastignitionplugs,

top dead

combustion

devicesmicrowave

its

and/ormaybemethods,

ignitiondevicesor

exhaust

gases

are

through compression ignition methods.
Duringtheexhauststroke,pumped out of the expansion cylinder 14 through exhaust port
35 disposed in cylinder head 33.
exhaust valve 34,30

port 35,

An inwardly opening poppet

disposed in the inlet 31 of the exhaust

controls fluid communication between the expansion

cylinder 14 and the exhaust port 35.
and

the

exhaustpassage 22.

port

35

are

separate

The exhaust valve 34
from

the

crossoverThat is, exhaust valve 34 and the exhaust port

wo 2011/115868

PCT/US2011/028276

1235 do not make contact with,or are not disposed in,thecrossover passage 22.
With the split-cycle engine concept, the geometricengine5parameters

length,volumetriccompression

12

and

bore,

stroke,connecting

rodcompression

ratio,

etc.)

the

expansion

14cylindersofaregenerally

independent from one another.

For example, the crank throws

36,

cylinder38forcylinder 14,
10(i.e.,

thecompression

12

and

expansionrespectively, may have different radii and may

be phased apart from one another such that top dead center(TDC)

of the expansion piston 30 occurs prior to TDC of thecompression piston 20.
cycle

engine10

toThis independence enables the split-

potentiallyachievehigherefficiency

levels and greater torques than typical four-stroke engines.
15

The geometric independence of engine parameters inthe split-cycle engine 10 is also one of the main reasons
why pressure can be maintained in the crossover passage 22
as discussed earlier.
reaches

20

its

top

Specifically, the expansion piston 30

deadcenterposition

prior

to

the

compression piston reaching its top dead center position bya discreet phase angle(typically between 10 and 30

crank

angle

phase

properdegrees).

This

angle,

togetherwithtiming of the XovrC valve 24 and the XovrE valve 26, enables
the25

split-cycle

engine10

tomaintainpressurecrossover passage 22 at a high minimum pressure

in

the

(typically

20 bar absolute or higher during full load operation) during
all four strokes of its pressure/volume cycle.

That is, thesplit-cycle engine 10 is operable to time the XovrC valve 24
and the XovrE valve 26 such that the XovrC and XovrE valves30

are both open for a substantial period of time (or period of
crankshaft

rotation)

during whichtheexpansion piston

30

descends from its TDC position towards its BDC position andthecompression piston

2 0 simultaneously ascends

from

its

wo 2011/115868

PCT/US2011/028276

13

BDC position towards its TDC position.
time
26(or crankshaft rotation)

are

both

transferred
5

( 1)

a

the

from theperiod,from

expansionthat the crossover valves 24,

substantially

equal

mass

of

compression cylinder 12crossover passage 22 andto(2)cylinder

air

is

into

the

from the crossover passage 22
14.

Accordingly,

duringthisthe pressure in the crossover passage is prevented

dropping(typically
10

open,

During the period of

20,

below

a

predetermined

minimum

30,

40

bar

duringorabsolutepressure
full

load

operation).

Moreover,engine cycle(typically 80% of the entire engine cycle orgreater),during a substantial portion of thethe XovrC valve

24

and XovrE valve

26

are bothclosed to maintain the mass of trapped gas in the crossover
passage 22 at a substantially constant level.
15

As a result,the pressure in the crossover passage 22 is maintained at apredetermined minimum pressureduringallfourstrokesofmethodofhavingthethe engine's pressure/volume cycle.
For

purposesherein,the

XovrC 24 and XovrE 26 valves open while the expansion piston
20

30 is descending from TDC and the compression piston 20 isascending toward TDC in order to simultaneously transfer a
substantially

equal

mass

of

gas

into

and

out

of

the

crossover passage 22 is referred to herein as the Push-Pullmethod of gas
25

enablesthetransfer.

pressure

in

It

is

the

Push-Pull method thatthecrossoverpassage

22

of

the

split-cycle engine 10 to be maintained at typically 20 bar
or higher during all four strokes of the engine's cycle whenthe engine is operating at full load.

30

As

discussed

disposedintheseparatefromearlier,theexhaust

port

of

the

cylinderpassage

22.

The

exhaustthecrossover35

arrangement of the exhaust valve 34
the crossover passage 22,

valve

34

is

head

33

structural

not being disposed inand therefore the exhaust port 35

wo 2011/115868

PCT/US2011/028276

14

not

sharing any common portion with thecrossover passage

22,

is preferred in order to maintain the trapped mass ofgas in the crossover passage 22 during the exhaust stroke.
Accordingly,
5

large

cyclic drops

in pressure

are prevented

which may force the pressure in the crossover passage below
the predetermined minimum pressure.
XovrE valve 26 opens shortly before the expansion

10

piston30

reaches

its

time,

the

pressure

top dead center position.

ratio

of

the

pressure

At

in

this

crossoverpassage 22 to the pressure in expansion cylinder 14 is high,due to the fact that the minimum pressure in the crossover
passageistypically20

barabsoluteorhigherandthepressure in the expansion cylinder during the exhaust stroke
is typically about one to two bar absolute.
15

when XovrE valve 26 opens, the pressure in crossover passage
22

issubstantially higher than the pressure

cylinder 14
This

high

and/or20

In other words,(typically in the order of 20 to 1 or greater).
pressurefuelhigh speeds.

ratio

chargetocausesflow

initial

into

flow

expansion

the25

advantageous

it causes

split-cycle

pressures

the
14

air
at

These high flow speeds can reach the speed ofparticularly

becauseofcylindersound, which is referred to as sonic flow.
isin expansion

even

a

to

This sonic flow

split-cycle

rapid combustion event,engine10

tothoughignitionmaintainisengine10

which enables

highinitiatedcombustion
while

the

expansion piston 30 is descending from its top dead center
position.
The split-cycle air-hybrid engine 10 also includes
an air reservoir
30(tank)

40,

which is operatively connectedto the crossover passage 22 by an air reservoir (tank) valve
42.

Embodiments with two or more crossover passages 22 may

include a tank valve 42 for each crossover passage 22, whichconnect to a common air reservoir 40,

or alternatively eachwo 2011/115868

PCT/US2011/028276

15crossover passage 22 may operatively connect to separate air
reservoirs 40.
The tank valve 42 is typically disposed in an air

5reservoir(tank)

passage 22

toasecond44,whichextends

the air tank 40.

divided into a
and

port

first
air

crossover

The air tank port

air reservoir

reservoir

from(tank)(tank)

port

44

is

port section 46
section

4 8.

The

first air tank port section 46 connects the air tank valve
42 to the crossover passage 22, and the second air tank port
10

section 4 8 connects the air tank valve 42 to the air tank
40.

The

includesvolumetheofvolume

the
of

first
all

air

tank

additional

port

ports

sectionand46

recesses

which connect the tank valve 42 to the crossover passage 22
when the tank valve 42 is closed.
15

The tank valve 42 may be any suitable valve device
or system.

For example, the tank valve 42 may be an active

valve which is activated by various valve actuation devices(e.g.,

pneumatic,

Additionally,20

hydraulic,the tank valve

system with two

cam,electricorthelike).

42 may comprise a tank valve

or more valvesactuated with two

or moreactuation devices.
Air

tank

40

is

utilized to

store

energy intheform of compressed air and to later use that compressed air
to
25

power

the

crankshaft

16,

as

described

intheaforementioned United States Patent No. 7,353,786 to Scuderi
et al.

This mechanical means for storing potential energy

providesnumerousstate of the art.

potential

advantages

For instance,

over

the

current

the split-cycle engine 10

can potentially provide many advantages in fuel efficiency
30

gains

and

NOx

emissions

reductionatrelatively

lowmanufacturing and waste disposal costs in relation to othertechnologies

on

the

market,electric-hybrid systems.

such

as

dieselenginesandwo 2011/115868

PCT/US2011/028276

16

By
closingofselectively
the

air

tank

controlling

the

valve

thereby42

andopening

and/orcontrolling

communication of the air tank 40 with the crossover passage
22,5

the split-cycle air-hybrid engine 10 is operable in an

Engine Firing

(EF)

mode,

an Air Expander

(AE)

mode,

an AirCompressor (AC) mode, an Air Expander and Firing (AEF) mode,
and a Firing and Charging (FC) mode.

The EF mode is a non-hybrid mode in which the engine operates as described above

10

without the use of the air tank 40.

The AC and FC modes areenergymode

storagemodes.

The

AC

is

an

air-hybrid

operating mode in which compressed air is stored in the air
tank

15

40

without

combustion

cylinder14(i.e.,

utilizingthekinetic

engineduring braking.

10

nooccurringfuelenergyintheexpenditure) ,expansion

such

as

by
the

of

a

vehicleincluding

The

FC

mode

an

is

air-hybrid

operating mode in which excess compressed air not needed for
combustion isstored in the air tank 40,

than full engine load
at constant speed) .
20

mode

has

an

(e.g.,

engine idle,

such asatlessvehicle cruising

The storage of compressed air in the FCenergycost(penalty);

therefore,itisdesirable to have a net gain when the compressed air is usedat alater time.

usage modes.

The AE and AEF modes are stored energy

The AE mode is an air-hybrid operating mode inwhich compressed air stored in the air tank 40 is used to25

drive the expansion piston 30 without combustion occurringin the expansion cylinder 14
The

AEF

mode

is

an

(i.e.,

air-hybrid

no

fuel

operatingexpenditure).
mode

in

which

compressed air stored in the air tank 40 is utilized in the
expansion cylinder 14 for combustion.
30

In
preferably

the

kept

crankshaft 16

AEF

mode,

the

air

open

throughtheentire(i.e.,

tank

valve

42

is

rotationofthethe air tank valve 42 is kept open atleast during the entire expansion stroke and exhaust strokewo 2011/115868

PCT/US2011/028276

17of the expansion piston).

Thus, compressed air stored in the

air

from

tank

40

is

released

the

air

tank

40

into

the

crossover passage 22 to provide charge air for the expansion
cylinder 14.
5

Also, the XovrC valve 24 is kept closed throughthe entire rotation of the crankshaft 16,
the compression cylinder 12,
expansion

pistoncompressed air
expansion
1030

expansion stroke,
the

same

which may be deactivated.

operates(from the air

cylinder

14

with

in

its

fuel,

strokepower

tank 40)atwhich is ignited,

expansion

thereby isolating

of

is
the

mode,

The

in

that

admitted tothebeginning

anofburned and expanded ontheexpansiontransmitting power to the crankshaft 16,

piston30,

and the combustion

products are discharged on the exhaust stroke.
The timing of the XovrE valve 26 closing at the15

beginning of the expansion stroke
30

descends

efficiency

from
of

top

the

dead

engine(as the expansion piston

center)
10

in

is

the

significant
AEF

mode.

to

the

This

is

because, when the XovrE valve 26 is open, the volume of thecrossover passage 22
20

is part of theclearance space above

the piston wherein combustion takes place.

Yet virtually

all of the fuel is in the expansion cylinder 14, and none of
it is in the crossover passage 22.
is closed,

Once the XovrE valve 26

the entire combustion process is confined to the

expansion cylinder 14, and the expanding combusting mass of
25

fuel

and air can most effectively do work upon the piston

30.
The later the XovrE valve 26 closes,
the residual
which
30

is

(i.e.,

definedeffective volumetric)

as

the

ratio

(a/b)

volume in the expansion cylinder 14

of(i.e.,

the smaller

expansion ratio,
(a)

the

the volume of achamber generally defined by the cylinder 14 wall,of the expansion piston 30,
head

33)

when

the

expansion

trappedthe topand the bottom of the cylinder
piston30

isatbottom dead

wo 2011/115868

PCT/US2011/028276

18

center to(b)the trapped volume in the expansion cylinder

14 at the time just when the XovrE valve 26 closes.

Once

the XovrE valve 26 is closed during the expansion stroke ofthe5

expansionpresent

solelypiston30,

inexpansion

the

the

produced as the mass expands.

expandingtrapped

mass

is

14

work

is

cylinderClearly,

andthe later the XovrE

valve 26 closes, the farther the expansion piston 30 is from
top

dead

ratio
10

center,

and

the

thus
less

the

smaller

work

that

the

is

residual

produced

expansion

duringexpansion stroke.
As

shown

deterioration

ininengineFIG.

2,efficiency

to

avoid

in

the

significant

AEF

mode,

residual expansion ratio should be 15.7:1 or greater.
preferably,
15

the

the

residual

expansion ratio

range of 15.7:1 and 40.8:1.

should be

the
More

in theIn this exemplary embodiment,in order to achieve a residual expansion ratio of 15.7:1 orgreater,22

the XovrE valve should be closed at approximately

degrees

embodiment,
20

CA

or

less

ATDCe.

Also

in

this

exemplaryin order to achieve a residual expansion ratioof 4 0. 8: 1 or greater,

the XovrE valve should be closed at

approximately 7 degrees CA or less ATDCe.
The upper range of the residual expansion ratio in
the AEF mode is always greater than the upper range of theresidual expansion ratio in an Engine Firing
25

any given applicationengine speed).

(i.e.,(EF)mode forat any given engine load andAlso, the actual residual expansion ratio in

the AEF mode is typically greater than the actual residual
expansion ratio in an Engine Firing (EF) mode of the engine,
particularly when the air tank is substantially full30

when the air tank pressure
the rated full pressure,apossible

30

bar

full

is

at

(i.e.,

approximately two-thirds

for example 20 bar or above out oftank) .

In

the

EF

mode,

the

compressed air used for combustion in the expansion cylinder

wo 2011/115868

PCT/US2011/028276

19

isprovidedproduce

by

the

the

compression

compressed air,thecylinder.

In

compression

cylinder must

perform negative pumping work (y).
the5desiredload

output

(x),

order

to

Thus, in order to obtainthe

expansion

pistonmust

produce a total amount of work equal to x + y so that the
net output is x + y - ythecompressed

air

=

used

x.

In contrast,for

combustionin the AEF mode

in

the

expansion

cylinder is provided from compressed air previously stored

10

15

in the air tank.

Since the compression cylinder does nothavecompressedtoproduce

air

in

the

AEF

mode,

the

compression cylinder is preferably deactivated,

and as such

the

no

compression

pistonperforms

littletonegativepumping work.

Thus,in order toobtain thedesired load

outputexpansion piston

only needs

to produce

(x),

the

total amount of work equal to approximately x.

aBecause theamount of work produced by the expansion piston in the EF
and AEF modes is essentially dependent upon the mass of fuelthat is consumed, and further because the mass of air neededin the expansion cylinder is directly related to the mass of
20

fuel

(in order to maintain a suitable, e.g., stoichiometric,

air to fuelratio),

a greater amount of compressed air isrequired in the EF mode than in the AEF mode to produce thesame net load output.
a25

greateramountof

For the expansion cylinder to receive
compressed

air,

the

XovrE

valve

generally must be held open longer in the EF mode than in
the AEF mode.
lower

the

The longer the XovrE valve is held open,

residual

expansion

ratio.

Hence,

thethe

residual

expansion ratio generally is greater in the AEF mode than in
the EF mode for a given engine load.
30

FIGS.

3 through 8 are graphical illustrations of

exemplary XovrE valve 26 closing timings across a range ofengine speeds
IMEP),(1000 to 3500 rpm),

engine loads(1 to 4 barand air tank 40 pressures(10 to 30 bar)in the AEF

wo 2011/115868

PCT/US2011/028276

20
mode.
air

For example:

tank pressure

(i)

of

at

1000

15 bar,

5

(FIG.

3);

(ii)

IMEP,
is

and an air tank pressure of 15 bar,at 2000 rpm,

25 bar,3 bar IMEP,

(FIG.

tank

pressure

5);

(iv)

IMEP,

of

15

bar,

the

and

an

air

tank

3.5 bar IMEP,

XovrE

valve

is

and (vi)

15

the XovrE
(FIG.

4);

at 3500 rpm,

bar,

the

degrees ATDCe

reference

(FIG.

8).

Although

the

to

a

valve

closed

at

6) ;

(v)

at 3 0 0 0 rpm,pressure

of

15

bar,

2.5 bar IMEP,

XovrE

and an air(FIG.

valve is closed at approximately 22 degrees ATDCe

25

rpm,

and an air tank pressure ofat 2500 rpm,

approximately 18 degrees ATDCeofclosed at

the XovrE valve is closed at approximately 9 degrees

ATDCe

bar

and anat 1500

valve is closed at approximately 15 degrees ATDCe
(iii)

10

1.5 barthe XovrE valve

approximately 13 degrees ATDCe
2.5 bar IMEP,

rpm,

is

has

specific embodiment,

XovrE

(FIG.

7);

and an air tank pressure

closedinvention

the

4

at

approximately

been

described

7

by

it should be understoodthat numerous changes may be made within the spirit and scope
of
20

the

inventive

concepts

described.

Accordingly,itisintended that the invention not be limited to the describedembodiment,

but

that

it havethelanguage of the following claims.

full

scope defined by thewo 2011/115868

PCT/US2011/028276

21
CLAIMS

What is claimed is:5

A split-cycle air-hybrid engine comprising:1.

a crankshaft rotatable about a crankshaft axis;acompression

compression
crankshaft
10cylinder
such

that

pistonslidablyreceived

withinandoperatively

connected

tothecompression

pistonathe

reciprocatesthrough an intake stroke and a compression stroke during asingle rotation of the crankshaft;an15

expansion

expansion

cylindercrankshaft

suchpistonandthat

slidablyreceived

withinanoperatively

connected

to

the

the

expansion

pistonreciprocatesthrough an expansion stroke and an exhaust stroke during asingle rotation of the crankshaft;a20

crossoverpassageinterconnecting

compression and expansion cylinders,theincludinga(XovrC)

crossover

expansion

crossovercompression(XovrE)

valve

the

crossover passage
valve

and

a

pressuredefiningachamber therebetween;ancrossoverairreservoir

passageandoperatively

selectively

connected

operable

to

to

the
store

compressed air from the compression cylinder and to deliver25

compressed air to the expansion cylinder; andan air reservoir valve selectively controlling air
flow into and out of the air reservoir;
the engine being operable in an Air Expander andFiring30(AEF) mode,

wherein,in the AEF mode,the engine hasa residual expansion ratio at XovrE valve closing of 15.7 to
1 or greater.
2.
claim 1,

wherein,The

split-cyclein the AEF mode,

air-hybrid

engineofthe residual

expansion

wo 2011/115868

PCT/US2011/028276

22
ratio at XovrE valve closing is in the range of 15.7 to 1
and 4 0. 8 to 1.
3.
wherein,5

The split-cycle air-hybrid engine of claim 1,

in the AEF mode,

the XovrE valve is closed at 22

degrees CA or less after top dead center of the expansion
piston (ATDCe)
4.
wherein,

The split-cycle air-hybrid engine of claim 1,

in the AEF mode,

the XovrE valve isclosed ataposition between 7 and 22 degrees CA after top dead center
10of the expansion piston (ATDCe).
5.
whereinat

The split-cycle air-hybrid engine of claim 1,
a

given

engineload

andenginespeed,

theresidual expansion ratio in the AEF mode is greater than theresidual expansion ratio
15

in an Engine Firing(EF)mode ofthe engine when the air reservoir is substantially full.
6.
whereinthethirdsor

The split-cycle air-hybrid engine of claim 5,
airreservoir

greater

than

a

is

at

rated

a

pressure

full

that

pressure

of

is

two-

the

air

reservoir.
20

7.

The split-cycle air-hybrid engine of claim 1,

wherein an upper range of the residual expansion ratio

inthe AEF mode is always greater than an upper range of theresidual expansion ratio

in an Engine Firing(EF)mode atany given engine load and engine speed.
258.

The split-cycle air-hybrid engine of claim 1,

wherein, in the AEF mode, the air reservoir valve is open.
9.
wherein,

The split-cycle air-hybrid engine of claim 1,

in the AEF mode,

the air reservoir valve is open

during the entire expansion stroke and exhaust stroke of the30

expansion piston.
10.
wherein,in

The split-cycle air-hybrid engine of claim 1,
the

AEF

mode,

compressed

air

from

the

air

reservoir is admitted to the expansion cylinder with fuel,wo 2011/115868

PCT/US2011/028276

23
at the beginning of an expansion stroke,burnedandexpanded

expansion piston,
the5

combustion

on

the

of

the

transmitting power to the crankshaft,andproducts

samewhich is ignited,areexpansiondischarged

strokeontheexhauststroke.
11.

Amethodofoperatingasplit-cycle

air-hybrid engine including:a crankshaft rotatable about a crankshaft axis;
a10

compression

compression
crankshaft

cylinder
such

that

pistonslidablyreceived

withinandoperatively

connected

tothecompression

pistonathe

reciprocatesthrough an intake stroke and a compression stroke during asingle rotation of the crankshaft;an15

expansion

expansion

cylindercrankshaft

suchpistonandthat

slidablyreceived

withinanoperatively

connected

to

the

the

expansion

pistonreciprocatesthrough an expansion stroke and an exhaust stroke during asingle rotation of the crankshaft;a20

crossoverpassageinterconnecting

compression and expansion cylinders,theincludinga(XovrC)

crossover

expansion

crossovercompression(XovrE)

valve

the

crossover passage
valve

and

a

pressuredefiningachamber therebetween;
an25

crossoverairreservoir

passageandoperatively

selectively

connected

operable

to

to

the
store

compressed air from the compression cylinder and to delivercompressed air to the expansion cylinder; andan air reservoir valve selectively controlling air
flow into and out of the air reservoir;30

the engine being operable in an Air Expander andFiring (AEF) mode;the method including the steps of:
opening the air reservoir valve;wo 2011/115868

PCT/US2011/028276

24

admitting5

compressed

air

from

the

air

reservoir

into the expansion cylinder with fuel,at the beginning ofanignited,expansion

stroke,thetheexpansion

strokepower

theexpandedonsame

piston,transmitting

fuel

to

being

of

burnedtheandexpansion

crankshaft,

and

the

combustion products being discharged on the exhaust stroke;andmaintainingaresidual

expansion

ratio

at

XovrE

valve closing of 15.7 to 1 or greater.
10

12.
maintaining

The method of claim 11, including the step oftheresidual

expansion

ratio

at

XovrE

valve

closing in the range of 15.7 to 1 and 40.8 to 1.
13.

The method of claim 11, including the step ofclosing the XovrE valve at 22 degrees CA or less after top
15

dead center of the expansion piston (ATDCe) .
14.

The method of claim 11, including the step ofclosing the XovrE valve between 7 and 22 degrees CA after
top dead center of the expansion piston (ATDCe) .
15.
20

The method of claim 11, including the step ofmaintaining the residual expansion ratio in the AEF mode ata value that is greater than the residual expansion ratio in
an Engine Firing (EF) mode at a given engine load and engine
speed when the air reservoir is at a pressure that is twothirds

25orgreater

than

a

rated

full

pressure

of

the

air

reservoir.
16.
keeping

open

The method of claim 11, including the step of
the

air

reservoir

valve

duringtheentireexpansion stroke and exhaust stroke of the expansion piston.

wo 2011/115868

PCT/US2011/028276

1/8

FIG. 1

:.;;
0
N
0

FIG. 2......
......
......
......

--

Residual Expansion Ratio At XovrE Valve Closing
50
45
40

Ut

QCI

a\

QCI

I\
'

35
30
Residual
Expansion Ratio(-) 25
20
15
10

5

Exemplary Ranges For ~xpansion R atio@ XovrE Closing
15.7:1 @ ~2 dea ATDC e
10.0:1 @ 30 deg ATDC e-Nnrrr 1;::!1 Firinn·~\-Air Ex pander+Firin p: 40.8:1@ 7 degATD ~e
15.7:1 ~ 22 deq ATD ~e\-1\..)

\

(X)

\ --

~Air Expa hder+Firing: XovrE close sat 7-22 deg ATDCe\-\~Nor tnal Firing: XpvrE closes at 22-30 deg ATDCe~~ .......__,_'"d('""')g00'"""""-

00N0......
......

30

60

90

120
150
XovrE Closing Angle (deg ATDCe)

180

0N

QCI

N
-..l
a\

wo 2011/115868

PCT/US2011/028276

3/8

FIG. 3
XoverE Valve Closing @ 1OOORPM

20

ATDC

1 7.00
2 9.003 11.00
4 13.00
5 15.00
6 17.00
7 19.00
8 21.00
Min. 19.9
Max. 7.94

18

~
:::J

16

en
en

(])
I....

a...
~

c
~ 14

12

10
1.0

1.5
IMEP (bar)2.0

wo 2011/115868

PCT/US2011/028276

4/8

FIG. 4
XoverE Valve Closing @ 1500 RPM
30 .-------.,....-----.,....------,---------,

--.
I....

co

---

..0
(])

I....

:::J

en
en
(])
I....

a...

ATDC

1 3.00
2 5.00
3 7.00
4 9.005 11.00
25
6 13.00
7 15.00
8 17.00
9 19.00
10 21.00
11 23.00
20 1----~~----+----~-+--------t Max. 22.3
Min. 3.23~c~

10 L....----~---....l....-~;..__-....1....--=::::;....._-----1
1.0
1.5
2.0
2.5
3.0
IMEP (bar)wo 2011/115868

PCT/US2011/028276

5/8

FIG. 5
XoverE Valve Closing @ 2000 RPM
30 .-----~------,----r-----,-----~---,

ATDC

1 3.00
2 6.00
3 9.004 12.00
5 15.00
25
6 18.00--.
7 21.00
co..0
8 24.00
9
27.00(])
10 30.00:::Jenen
Max. 28.9(])
a... 20 1 - - - - - - - - + - - + - - - - + - - - - + - - + - - - - - - - - - j Min. 3. 97
I....

--I....

I....

~

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PCT/US2011/028276

6/8

FIG. 6
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30 .------------,--~----,---------::::::;~,........,

ATDC

1
2
3

0.0
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8.0
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Min. 0.3

25
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7/8

FIG. 7
XoverE Valve Closing @ 3000 RPM
30 .----~-------,------r----...,....--------,

ATDC

1 2.0
2 6.0
3 10.04 14.05 18.025
6 22.0--.
7 26.0co..08 30.09
34.0(])
10 38.0:::J
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Max. 34.6
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a... 20 1----+-----+------+----_______,.'----------l Min. 2.8
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8/8

FIG. 8
XoverE Valve Closing @ 3500 RPM
30 .------------,----"""7""""--,------~---,

ATDC
0.0
2 5.0
3 10.04 15.05 20.06 25.07 30.08 35.09 40.0Max. 38.7
Min. 1.1
1

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2

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INTERNATIONAL SEARCH REPORTInternational application No.
PCT/US2011/028276

A.

CLASSIFICATION OF SUBJECT MA TIER

IPC(8) - F02B 33/22 (2011.01)
USPC- 123fiOR
According to International Patent Classification (IPC) or to both national classification and IPC

B.

FIELDS SEARCHED

Minimum documentation searched (classification system followed by classification symbols)
IPC(8) - F02B 33122 (2011.01)
USPC- 60/620, 712; 91/181; 123/27R, 52.3, 52.5, 53.1, 53.5, 58.8, 68, 70R, 253,258, 286, 292; 417/237
Documentation searched other than minimum documentation to the extent that such documents are included in the fields searchedElectronic data base consulted during the international search (name of data base and, where practicable, search terms used)
PatBase, Google Patent, PAIRC.

DOCUMENTS CONSIDERED TO BE RELEVANT

Category•

Citation of document, with indication, where appropriate, of the relevant passages

Relevant to claim No.

X

US 2007/0157894 A1 (SCUDERI et al) 12 July 2007 (12.07.2007) entire document

1-16

A

US 2009/0272368 A1 (BRANYON et al) 05 November 2009 (05.11.2009) entire document

1-16

A

US 2006/0124085 A1 (LUTIGEHARM) 15 June 2006 (15.06.2006) entire document

1-16

A

US 4,696,158 A (DEFRANCISCO) 29 September 1987 (29.09.1987) entire document

1-16

A

US 1 ,350,570 A (SARJENT) 24 August 1920 (24.08.1920) entire document

1-16

D Further documents are listed in the continuation of Box C.
•

"A"
"E"

"L"
"0"

"P"

Special categories of cited documents:
document defining the general state of the art which is not considered
to be of particular relevanceearlier application or patent but published on or after the international
filing datedocument which may throw doubts on priority claim(s) or which iscited to establish the publication date of another citation or otherspecial reason (as specified)
document referring to an oral disclosure, use, exhibition or othermeans
document published prior to the international filing date but later thanthe priority date claimed

Date of the actual completion of the international search
04 May 2011
Name and mailing address of the !SAlUS
Mail Stop PCT, Attn: !SAlUS, Commissioner for Patents
P.O. Box 1450, Alexandria, Virginia 22313-1450
Facsimile No. 571-273-3201
Form PCTIISN21 0 (second sheet) {July 2009)D"T'

later document published after the international filing date o1eriority
date and not in conflict with the apJ:Iication but cited to un erstandthe principle or theory underlying e invention"X" document of particular relevance; the claimed-invention cannot be

considered novel or cannot be considered to involve an inventive
step when the document is taken alone"Y" document of particular relevance; the claimed invention cannot be
considered to involve an inventive step when the document iscombined with one or more other such documents, such combination
being obvious to a person skilled in the art"&" document member of the same patent family

Date of mailing of the international search report

1 2 MAY 2011
Authorized officer:
Blaine R. Copenheaver
PCT Hetpdesk: 571-272-4300
PCT OSP: 571·272-7774