DFDAIHATSU DIESEL
Dual-Fuel Engines

DE20DF DE23DF
DE28DF DE35DF

Daihatsu Diesel Duel-Fuel Engines:
High Environmental Performance throughPrecise and Detailed Control
Dual-fuel engines that operate on both environmentally friendly natural gas andconventional petroleum fuel require precise control and must offer high safety and durability.
Daihatsu Diesel has incorporated the results of extensive research on the internal combustion engine
into the development of our dual-fuel engines.
Daihatsu Diesel dual-fuel engines offer accurate and stable operation on natural gas while
incorporating the excellent environmental performance inherited from the company's diesel engines,
which boast features such as a fuel injection system with high control precision,
superb fuel efficiency,
and outstanding engine durability.

DFDAIHATSU DIESEL
Dual-Fuel Engines

2

DE20DF DE23DF
DE28DF DE35DF

Compliance with NOx
Tier III standards ingas mode and Tier IIstandards in diesel mode

20
IMO Tier I regulation value

NOx [g/kWh]

16Diesel mode

12

IMO Tier IIregulation value

80Gas mode

IMO Tier III regulation value

40300

600900Engine Speed [min-1]

1200

1500

No change to engine
rotation speed whenswitching to gas modeor diesel mode
70700

Speed control■ Dieselmode
Gas mode
60 Diesel
fuel→governor
Gas governor

600

50 Diesel fuel governor position
500
90900
40400
80
Engine rotation speed 800
30
Gas valve open duration
Diesel fuel governor position 300
70700
Increaseat constant
Decrease at constant rate
control
20 Speed200rate
60 Diesel
600
Completionoffuel governor
Gas governor
switchover
10 Start of switchover
100
500
50 Diesel
fuel governor position
operation
operation
0040 010203040506070400* Measurements

30300
Time [sec]Gas valve open duration
Diesel fuel governor
positionobtained
at 50% load
Increase at constant
Decrease at constant rate
200rateCompletion ofStart of switchoverswitchover
100
operation
operation

20
100

Engine rotationEngine
speed rotation[min-1] speed [min-1]

Gas injection timing
Gas injection[degCA] timing [degCA]
Diesel fuel governor
Dieselposition
fuel governor[%] position [%]Advanced fuel injection control ensures a smoothswitchover to gas mode or diesel mode without
90 the engine rotation speed. This eliminates
900
changing
80 interruption when switching
Engine rotationmodes.
speed 800
any output01020304050

Time [sec]60070* Measurements
obtained at 50% load

9009080800

Engine rotation speed

70

700

60 Gas injection timing
600
Diesel fuel governor position
50500
90
900
40 Speed control
400
80
800
Engine rotation speed
30 Gas governor
300
Diesel fuel governor
70
700
200
2060 Gas injection timing
600
Diesel fuel governor position 100
1050
500
00
40 0 Speed1control 234567 400*Measurements
30 Gas governor Time300
Diesel[sec]fuel governor

obtained at 100% load

20200

100Engine rotationEngine
speed rotation[min-1] speed [min-1]■ Gas mode → Diesel mode
Gas injection timing
Gas injection[degCA] timing [degCA]
Diesel fuel governor
Dieselposition
fuel governor[%] position [%]Type approval certificate

Daihatsu Diesel dual-fuel engines comply with theIMO NOx Tier III standards when running in gas
mode and with the Tier II standards when running indiesel mode. The operating mode can be switchedas needed, such as when navigating on a sea whereclean engine operation is required or when there isa fuel procurement issue. They can operate in themost suitable mode according to the situation.

10001234Time [sec]5670* Measurements
obtained at 100% load

3

Sophisticated Technologies Behind High Efficiency
Technologies that have been accumulated through the development of diesel engines
were applied to develop the gas combustion system.
High-efficiency combustion is ensured in both gas mode and diesel mode operation.

Accurate fuel injection
using a common rail

A common rail system is used for the pilot fuelinjection. A precise amount of high-pressure fuelis injected at the optimal timing according to theoperating condition, thus helping to improve fueleconomy and reduce NOx.

Gas pipe(Double walled)
Gas admission valve
Exhaust pipe

Twin nozzles

Using the two injection devices, the main nozzle
and pilot nozzle, the valve train control systemachieves optimal and precise operation in eachcycle, thus attaining high combustion efficiency.
From thecommon rail
high-pressure
pumpDiesel injector(Water-cooled nozzle)
From the fuelinjection pump

Pilot
injector

Cylinderpressure
sensorPistonCylinder liner

Compatible withvarious types of fuelsGasmodeDieselmode

99％ Natural gas

1% MDO/MGO (pilot fuel)97％ MDO/MGO/HFO

3% MDO/MGO (injector cooling)Gas pipe featuring
a double-walledstructure
The gas pipe features
a double-walled
structure for extra
safety.
4* The parts indicated with the red background [■ ] aremodified from existing parts of conventional diesel engines.

DF
Dual-Fuel Engines

Variable valve timing
mechanism
Pilot injector
Diesel injector

Cylinder pressure
sensor

The valve train control system incorporates avariable valve timing mechanism. The system
optimally controls the timing of the valve opening
and closing according to the engine speed andload, thus helping to suppress NOx emission
and improve anti-knocking performance. It
also provides control to provide stable output atstartup and during low-load operation.
Change in roller
position

Swing arm shaft

Operated by rotary drive actuator

Fuelinjection
pump

Eccentric
shaftrotation

Intake cam

Intake air shortage occurs
at startup and under low
load operation, causing
the engine performance
to drop.(Starting failure,combustion failure, etc.)

Intakevalve

Valve lift

Exhaustvalve

A variable valvemechanism optimizes thevalve timing (controls theintake valve timing) sosolving this problem.

Crank angle

Swing arm
shaft

CamshaftFour-stage load input for superload response
Each system is optimally controlled to increase theload from startup to maximum load in four stages
in gas mode. This achieves quick increase of theengine speed to the usable range.
DE28DF
4-stage load
input

Max. Load Step [%]100

designed exclusively for the DF engine; other parts are80

LR rule (15-min standby)
80/Pme (2.0) = 40%

60

Other brand engine5-stage load input(example)

40
20
00

123

4

Number of Load Steps

565

■ External View
A*JF

B

G Piston & Rod

Height for Withdrawal ofH

D

E*

C

8DE35DF■ Dimensions and Mass
Model

Dimensions (mm)Dry mass*

A

B

C

D

E

F

G

H

J(ton)

6DE20DF

5510

3245

1830

1040

4290

1000

1530

1240

2035

20

6DE23DF

6000

3150

2200

1170

4600

1150

1720

1460

2300

27

6DE28DF

7190

3645

2230

1380

5600

1300

2065

2020

2580

40

6DE35DF

9065

3950

2570

1780

7460

1350

2555

2050

3270

81

8DE35DF

10470

4150

2570

1780

8895

135025552050

4330

98

* Actual dimensions and mass may vary depending on the specifications of the generator unit.

■ Main Specifications
Engine model

66DE20DF

6DE23DF

6DE28DF

6DE35DF

8DE35DF

Bore x Strokemm

Φ205×300

Φ230×320Φ280×390

Number of cylinders-

666

Rotation speedmin-1

900

900

720

Maximum engine output

kWm890

1,200

1,730

3,060

4,080

Maximum generator output

kWe

840

1,140

1,640

2,950

3,940

NOx emission rate-Fuel-

Pilot fuel-Φ350×440

6720≦ Tier III (gas mode)≦ Tier II (diesel mode)

Natural gas (gas mode)
MDO, MGO, (HFO) (diesel mode)
MDO or MGO

8Backed by R&D that takes marine use into fullconsideration, Daihatsu Diesel Dual-Fuel Engines
continue evolving.
At Daihatsu Diesel's Moriyama Factory, we take onboard
installation into full consideration in the research anddevelopment of marine engines. Through the R&D
process, our dual-fuel engines have been refined andcleared various issues that they might encounter in actualusage. We spare no effort in R&D. For example, we haveconstructed a natural gas supply facility on the premisesof the factory for the research and development of fuelsupply and storage equipment. We continue to make ourproducts safer and more reliable.

System overview
Silencer

Ventilation
Fan

Pressure Relief
Valve withFlame Arrestor
Purge
FanVentilation
Air Inlet
Inert Gas

FGSSEngine
Room

LNG Tank
ColdBox

DF Engine

Nitrogen
Generator
Tank etc

Gas
Valve
Unit7

www.dhtd.co.jp
Head Office
1-30, Oyodo Naka 1-chome, Kita-ku, Osaka, 531-0076 Japan
TEL: +81-6-6454-2393 FAX: +81-6-6454-2686

Tokyo Office2-10, Nihonbashi-Honcho 2-chome, Chuo-ku, Tokyo, 103-0023 Japan
TEL: +81-3-3279-0827 FAX: +81-3-3245-0359

Moriyama Division
45 Amura-cho, Moriyama-city, Shiga, 524-0035 Japan
TEL: +81-77-583-2551 FAX: +81-77-582-5714

Daihatsu Diesel Himeji Mfg. Co.,Ltd.
12-8, Fuji-cho, Hirohata-ku, Himeji-city, Hyogo, 671-1123 Japan

Daihatsu Diesel (EUROPE) Ltd.
TOG Borough Yards, 13 Dirty Lane, London, SE19PA, UK
TEL: +44-20-4566-5600

Daihatsu Diesel (AMERICA), Inc.
380 N Broadway, Suite 302, Jericho, N.Y. 11753 U.S.A.
TEL: +1-516-822-3483/4 FAX: +1-516-822-3485

Daihatsu Diesel (ASIA PACIFIC) Pte.Ltd.
16 Collyer Quay, Income at Raffles #29-02, Singapore 049318
TEL: +65-6589-9510 FAX: +65-6536-4964

Daihatsu Diesel (SHANGHAI) Co.,Ltd.
Room A-B, Floor 14, Huamin Empire Plaza, No.728, Yanan Rd.(W.),
Shanghai, 200050, China
TEL: +86-21-6225-7876/7 FAX: +86-21-6225-9299• All information contained in this pamphlet is correct at the time of printing,but may be subject to change without notice.

Printed in Japan000000