Development of a DME (Dimethy Ether)
Fueled Heavy-Duty Truck
Hiroshi Oikawa
1, Yoshio Sato 1 , Takayuki Tsuchiya 2
1
National Traffic Safety and Environment Laboratory, Japan
2
NISSAN DIESEL MOTOR CO, LTD, Japan
¾ EFV21 project
– Background, DME, Targets
¾ Technical challenges
– Engine
• DME Injection system
• High-EGR
– NOx storage reduction catalyst (NSR) – Test results
¾ Development of H/D DME truck
¾ Conclusions
Contents
Environmental impact of diesel trucks
Passenger cars
Mini sized trucks Light duty trucks
Standard trucks
Small sized trucks Passenger cars Buses
Special vehicles
NOx
FY2001
Gasoline 20 %
Diesel 80 %
Mini sized passenger cars
Standard Diesel trucks
Diesel small sized trucks Diesel
passenger cars
Diesel buses
PM
FY2001 Diesel
100％
Diesel special vehicles
Number ratio of diesel trucks ; 3.3 %
Task of EFV21 project
- from the Action Plan of Clean Vehicles (METI, MLIT, MOE, Jul. 2001)
- from the Working Group Report (MLIT, Dec. 2001 )
“The Next-Generation Low Emission Heavy-duty truck”
- drastic reduction of exhaust emission maintaining good fuel efficiency
- improvement of practical use
Output, Fuel economy, Cruising distance
Environmentally Friendly Vehicles 21
“EFV21” Project
Basic data of EFV21 project
¾ Time period:
– 3 years, from April 2002 through March 2005
¾ Subjects:
– Completion of prototype vehicles by March 2005, and evaluation of the vehicles' performance
¾ Prototype vehicles and engine:
– DME fueled truck, Ultra-Clean CNG fueled truck, Series H/B diesel bus, Parallel H/B diesel truck, Ultra-Clean diesel engine
¾ Development budget:
– Support from Ministry of Land, Infrastructure and Transport (MLIT),
– Total budget included all vehicles for 3 years;
Approximately 5 billion yen (approximately 42 million
dollars)
Pilot plant of DME (Kushiro City, 100ton/day,
Nov. 2003-, by support of METI）
DME is used as aerosol propellant (10,000ton/year in Japan)
Characteristics of DME
– Soot–free, Sulfur–free
– Higher H/C ratio, Low carbon fuel – Liquefied fuel under low pressure – Lower self ignition temperature
Dimethyl-Ether (DME) as clean diesel fuel
Chemical structure
DME is handled as a liquefied
gas C.I. combustion is possible
Application to Diesel engines
Development targets for DME truck
¾ Exhaust emissions (JE-05 mode, 2005):
NOx = 0.5g/kWh or less
PM ≒ 0.0g/kWh (nearly zero) CO = 2.22g/kWh or less
NMHC = 0.17g/kWh or less
¾ Fuel consumption:
Equivalent to base diesel engine
¾ Engine power:
Equivalent to base diesel engine
¾ Cruising distance and load capacity:
Equivalent to base diesel truck
Emission targets of EFV21 project
Emission regulation for H/D diesel engine
0.00 0.05 0.10 0.15 0.20 0.25
0 1 2 3 4
NOx g/kWh
PM g /k W h
2004 US
2007 US
2005 EURO4 2008
EURO5
2003/04 JAPAN
2005 JAPAN 2010
US
Strategic target, -2010
Target of EFV21 - Mar. 2005
2009 JAPAN
¾ EFV21 project
– Background, DME, Targets
¾ Technical challenges
– Engine
• DME Injection system
• High-EGR
– NOx storage reduction catalyst (NSR) – Test results
¾ Development of H/D DME truck
¾ Conclusions
Contents
Specifications of DME engine
Base engine NISSAN DIESEL FE6T
Cylinder L6
Bore / Stroke 108 / 126
Displacement 6,925cc
Charge type Turbocharger with intercooler
Achieved max. output 199kW at 2700rpm 750Nm at 1100rpm Achieved max. torque
Compression ratio 17.5
Valve system OHV (2 valves per cylinder)
Swirl ratio 1.9
Fuel injection system Jerk type In-line injection
DME engine combustion system
Injector
Piston Cylinder head
Nozzle :Φ0.38-5hole
Effect of injection pressure - Rated power -
0 50 100 150 200 250
Power [kW]
0 200 400 600 800 1000 1200
Exhaust tem p erature at turbine in let (K)
Upper Limit (750 deg.C)
Target power 38 MPa
29 MPa Pinj.=20 MPa
2700rpm
Nozzle : 0.38 X 5 holes without EGR & Catalyst
Injection system : Common-rail
Injection Timing : Constant
Characteristics of DME
Unit Liquid Density kg/m
3Cetane Number
Stoich. A/F ratio kg/kg
Boiling point K
C ratio wt%
H ratio wt%
O ratio wt%
Modulus of elasticity N/m
2Lower Calorific Value MJ/kg Vapor pressure (@293K) kPa Auto ignition temperature K
DME 667
>55 9 248 52.5
13 34.8 6.37 X 10
828.8 530 508 Diesel fuel
831 40-55
14.6 453-643
86 14 0
1.49 X 10
942.7
-
523
Optimization points for jerk injection system
Mechanical Timer Design of Timer Injection Pump
(PE-6ADS) Mechanical
Governor Change to
Electronic Governor
Nozzle (DLLA-S) Plunger Element
-Maximum Diameter of Series -Larger Effective Stroke
-Surface treatment
Cam Chamber
Filling up of Lubricating Oil
DME Tank Feed Pump
Concave Nose
Arc
Pump Cam
Design of Cam Profile
Design of Nozzle Needle Tip Nozzle
Improvement of Lubrication Lub. Improver; LZ539ST; 800ppm
Nozzle configuration
2.6 (Seat dia.)
3.8 (Seat dia) 0.9
(Sac dia.)
1.1 (Sac dia.)
4 4
DIESEL DME
Total nozzle hole are: twice of typical diesel injector
Specifications of jerk injection system
Baseline DME
Injection pump type PE-6AD Modified PE-6AD
Plunger Diameter 10.5 10.5
Cam Profile PEA-U-078 PEA-U-104
Delivery valve CPV STD
Nozzle Type DLLA-S DLLA-S
Hole number 5 6
Hole Dia. [mm] 0.28 0.37
Opening
press. [MPa] 16.7/19.6
(2 spring)
11.8/14.7 (2 spring)
Needle lift {mm] 0.35 0.40
Governor Mechanical type Electronic type
Timer
(max. advance) [deg. Crank] Mechanical type (10)
Mechanical type
(14)
Required inj. pressure for DME engine
0 10 20 30 40 50 60
500 1000 1500 2000 2500 3000 Engine speed [rpm]
Injection pressure [MPa]
Target
Jerk inj. system
Heavy load condition
Effect of nozzle hole number
1080rpm 650Nm
1620rpm 675Nm
2700rpm 560Nm NOx [ppm] CO [ppm] BSEC [MJ/kWh]
0 500 1000 1500
0 200 400 600 800 1000
5 holes
6 holes 7 holes
9 10 11 12
Hole number Hole diameter
5 0.38 6 0.35 7 0.32
* Total nozzle hole area is constant
Full load performance of DME engine
300 400 500 600 700 800
Torque [Nm]
500 1000 1500 2000 2500 3000 Engine Speed [rpm]
DIESEL (Target)
DME
NOx reduction by high EGR
60% speed (1620rpm)
-6 -4 -2 0 2 4 6 8 10
Rate of change of BSFC [%]
-100 -80 -60 -40 -20 0
0 5 10 15 20 25 30
EGR ratio [%]
NOxreduction rate [%]
Effect of EGR at 1620rpm High-EGR system
Turbocharger Air filter
EGR valve
DME engine
Inter-cooler
Exhaust manifold Intake manifold
EGR Gas
EGR Gas Throttle valve
20%Load 40%Load 60%Load 80%
Load
20%Load
40%Load
60%Load 80%Load
Air + EGR gas
High-pressure to
Low-pressure EGR
¾ EFV21 project
– Background, DME, Targets
¾ Technical challenges
– Engine
• DME Injection system
• High-EGR
– NOx storage reduction catalyst (NSR) – Test results
¾ Development of H/D DME truck
¾ Conclusions
Contents
NOx reduction concept
% 100
Optimum I/T and etc.
EGR (-50%) Base
50
0
NOx Emission
NOx Catalyst
(-80%)
0.5g/kWh
Target
試験触媒NX-2019-1 EGR OFF条件 温度（負荷）特性グラフ
0 100 200 300 400 500 600 700 800 900 1000
100 150 200 250 300 350 400
触媒入口温度（℃）
平均NOｘ(ppm)
0 10 20 30 40 50 60 70 80 90 100
浄化率（％）
浄化率
触媒入口 NOｘ
触媒出口 NOｘ
Catalyst B
NOx ppm Conversion Rate%
Catalyst Temperature ℃ NOx
in
NOx out C/R
試験触媒NX-2017-1 EGR OFF条件 温度（負荷）特性グラフ
0 100 200 300 400 500 600 700 800 900 1000
100 150 200 250 300 350 400
触媒入口温度（℃）
平均NOｘ(ppm)
0 10 20 30 40 50 60 70 80 90 100
浄化率（％）
浄化率
触媒入口 NOｘ
触媒出口 NOｘ
Catalyst A
NOx ppm Conversion Rate%
NOx in
NOx out C/R
Catalyst Temperature ℃
NSR catalyst
2.47 2.47 Volume
L
144×152 Pt / Pd
Catalyst B
144×152 Pt / Rh
Catalyst A
Size D×L mm Componen
t
Preliminary test of NSR catalyst
NSR catalyst
Exhaust gas temp. sensor NOx concentration sensor
Oxdation catalyst AD/DA
ボード
演算・制御部 噴射指令
信号
排出ガス温度 NOx濃度
エンジン回転速度 アクセル開度
Exhaust gas temp. sensor NOx concentration sensor
Development subjects
• Rich spike injection system
• Control of catalyst temp.
-Control of exhaust temp.
• Control of reducing agent -Control of F.C. loss -Reduction of HC slip
• Optimization of catalyst volume
Engine out
NOx CO HC
Exhaust
CO
2H
2O N
2Rich spike Rich spike Rich spike
injector Reducing agent
（DME）
Oxdation catalyst NSR catalyst
Injection unit of reducing agent
NSR catalyst system for DME engine
Base Base engine condition
EGR Exghaust Gas Recirculation control Optimization of NSR system
Control
1 R/S injection is applied in regular interval and quantity
2 Optimization in the R/S injection interval
3 Optimization in the R/S injection quantity
4 Precision of R/S interval and quantity
5 Installation of intake throttle and thermal insulation in exhaust system 6 Optimization of catalyst volume
(8L NSR catalyst + 5L NSR catalyst)
Optimization of NSR system
Test conditions Results of optimization
(JE-05 emission test)
¾ EFV21 project
– Background, DME, Targets
¾ Technical challenges
– Engine
• DME Injection system
• High-EGR
– NOx storage reduction catalyst (NSR) – Test results
¾ Development of H/D DME truck
¾ Conclusions
Contents
Results of JE-05 emission test
0 1 2 3
NOx NMHC CO
Exhaust emission [g/kWh]
0.00 0.01 0.02 0.03 0.04
PM
Exhaust emission [g/kWh]
0.001 2009 Regulation
Achievement data（Dec. 2004）
Target of project 2005 Regulation
0.11 0.12 0.21
Emission level of DME engine with NSR
Emission regulation for H/D diesel engine
0.00 0.05 0.10 0.15 0.20 0.25
0 1 2 3 4
NOx g/kWh
PM g /k W h
2004 US
2007 US
2005 EURO4 2008
EURO5
2003/04 JAPAN
2005 JAPAN 2010
US
Achievement data (Dec. 2004)
Target of EFV21 - Mar. 2005
2009 JAPAN
Trade-off characteristics
NOx [g/kWh]
BSFC [g/kWh]
200 250 300
3 4 5 6
2 1
0
EGR
Transient mode (JE-05 mode)
EGR + NSR DIESEL
DME
Steady state mode (Diesel 13 mode)
Target
0.5 g/kWh
CO 2 emission (D-13 mode test)
5 10 15 20 25
0
50g/kWh
CO
2range Of D.E.
DME Engine （EGR + NSR Cat.）
: NOx 0.35 g/kWh（JE-05）
: NOx 0.11 g/kWh（JE-05）
CO emission （g/kWh ）
2[ D-13 mode test ] 6.9L
CO
2range of D.E.
(Displacement：6.9L)
Engine displacement (L)
¾ EFV21 project
– Background, DME, Targets
¾ Technical challenges
– Engine
• DME Injection system
• High-EGR
– NOx storage reduction catalyst (NSR) – Test results
¾ Development of H/D DME truck
¾ Conclusions
Contents
Fuel, EGR and NSR system for vehicle
Silencer ECU
Turbocharger
EGR valve
Fuel Injector
ENGINE
Feed pump DME tank
Injection pump
Supply unit
of reducing agent
Oxidation catalyst
Oxidation catalyst
NOx storage reduction catalyst
Specification of H/D DME truck
NISSAN DIESEL, PW25A Heavy duty truck
Overall Length [m] 12
Overall Width [m] 2.5
Overall Height [m] 3.4 20]
342 (171 + 171) 627 *
*Calculated value from the JE-05 mode test result DME tank capacity [L]
Driveng mileage [km]
Base truck Type Dimension
Gross vehicle weight [ton]
DME engine
Feed pump
DME tank
Reducing agent Control unit
Fuel temperature control unit Fuel pressure &
Purge control unit
Acceleration performance
0 5 10 15 20 25
20 40 60 80 100 120
Power weight ratio GVW [kg] / max.power [kW]
Time [sec.]
GVW 14.4 ton GVW
9.1 ton
GVW 19.8 ton
DME
Diesel
Start-up performance
100 200 300 400 500 600
-1 0 1 2 3 4 5 6 7 8 9 10
Engine speed [rpm]
Idle speed : 530rpm
Cold-starting Hot-starting
Start of cranking
0 4 8 12 16 20
Control Rac k [mm]
0
¾ EFV21 project
– Background, DME, Targets
¾ Technical challenges
– Engine
• DME Injection system
• High-EGR
– NOx storage reduction catalyst (NSR) – Test results
¾ Development of H/D DME truck
¾ Conclusions
Contents
Conclusion
¾ The Output of DME engine exceeded base diesel engine by development of DME FIS.
¾ NOx storage reduction (NSR) system has been developed for a heavy-duty DME engine.
¾ Application of High-EGR and a NSR system enable NOx emission to reach ultra-low levels (0.11g/kWh) with PM free.
¾ The DME engine's CO 2 emissions are somewhat lower than those of diesel engine.
¾ The performance of DME truck was equivalent
to diesel truck.
Future plans
Step
2002 2005 2010 2015 2020
Engine and vehicle development
Development of H/D DME truck Budget year
Widespread Use Practical
Use Road
Vehicle Test
Infrastructure of DME
¾ By support of MLIT, future plans call for road vehicle test
of the developed heavy-duty DME truck, such as the
system‘s operation, practicality, reliability, durability, etc.,
can be studied under a variety of driving conditions.
Thank you for your kind attention !
Thank you for your kind attention !
Video of vehicle test
Video of vehicle test Click !
Questions and Discussions
Enforcement organization of “EFV21”
Development and Promotion Council Advice on execution
DME Vehicle Working Group Advice to development
Fuel Injection System Maker Fuel Supply System
Injector Maker C/R Injector Nissan Diesel
Engine and Truck Development
Waseda University Spray Combustion Research
Catalyst Maker Supplay of Catalyst
Hokkaido University Basic Research of NOx Catalyst
Bosch AJ
Research of Fuel Injection System
Overseas Organization Research Cooperation Jilin University, KATECH
NTSEL
Development of NOx Reduction Catalyst Research of Basic Technologies NTSEL
Execution Organization
Core Organization on Research and Development MLIT
Government Sponsorship
Effect of injection pressure - Low speed / heavy load-
30 32 34 36 38 40
0 200 400 600 800
NOx [ppm]
Thermal efficiency [%]
600 800 400
0 200 0 100 80 60 40 20
NOx [ppm]
THC [ppmC] 19MPa
21MPa 25MPa
25MPa
21MPa
19MPa 1200
0 1000 800 600 400 200
CO [ppm]
1080rpm, Torque = 650Nm
Nozzle hole diameter : 0.38 (5 holes) without EGR & Catalyst
Injection system : Common-rail
25MPa
19MPa
21MPa
Effect of swirl ratio
Pinj.=25MPa
10 15 20 25 30 35 40
0 100 200 300
Brake thermal eff iciency ( % ) 0
200 400 600 800 1000
CO [ppm]
1080rpm 2700rpm
0 200 400 600 800 1000
CO [ppm]
S/R=1.9 2.3
2.6
10 15 20 25 30 35 40
0
100 200
Brake thermal eff iciency ( % )
300
Injection quantity (mm
3/st-cyl) Injection quantity (mm
3/st-cyl)
Pinj.:40MPa
Nozzle:0.38mm-5holes S/R:1.9, 2.3, 2.6
Cavity diameter: 58mm
NOx behavior in JE-05 test mode
Actual driving mode for engine test
0 20 40 60 80 100
0 200 400 600 800 1000 1200 1400 1600 1800 2000
Time [Sec]
0 20 40 60 80 100 0 20 40 60 80 100
Speed [km/h]
0 20 40 60 80 100
HW1
（Ave. speed: 71.8km）N40
（Ave. speed: 39.5km）N5
（Ave. speed: 4.8km）JE05
（Ave. speed: 27.3km）Test results of NSR catalyst system
Test condition : EGR + NSR Catalyst Engine bench test
0.0 0.2 0.4 0.6 0.8 1.0
NO x ( g/ k W
N5 JE05 N40 HW1
試験モード
Half payload
Target
Driving mode
4.8 27.3 39.5 71.8 Average of vehicle speed (km/h)
JE-05 Test
0.0 0.2 0.4 0.6 0.8 1.0
NO x ( g/ k W
0 Half Full
Payload condition
Target
DME fuel system for vehicle
Fuel temperature control unit
Purge line
Supply & return line Re-liquefaction line
High pressure pump Injector
Feed pump Filter
Fuel temperature control unit
DME tank Purge tank
Re-liquefaction pump
Aspirator Aspirator
Suction Suction
Inlet
Inlet OutletOutlet
