2013-11-13
1
8th Asian DME Conference
Study Background
Study Contents - Development of CR DME Injector
- Development of DME HP Pump
- Development of CR DME E/G
- CR DME Vehicles for EURO-5
- Conclusions
Future Works
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2
Shale gas Revolution : The U.S. now seems to possess a 100-year supply of natural
gas, which is the cleanest of the fossil fuels –November 3 2011 New York Times.
- U.S. government's Energy Information Administration predicts that by 2035, 46% of the
USA’s natural gas supply will come from shale gas
shale gas - worldwide energy supply
- U.S., China, Argentina, Algeria, Canada and Mexico account for nearly two-thirds of the assessed, technically recoverable shale gas resource
Source: EIA, April 2011 – Study of 48 Basins in 32 countries including India
South Korea's second-biggest LPG importer E1 Corp said it would purchase
180,000 mt/year of LPG produced from US shale gas in 2014 because of 10%
lower than import prices of LPG produced in the Middle East.
SK Gas, Korea's biggest LPG importer, also considering buying LPG produced from
shale gas to help lower import costs
Korean government has vowed to invest more in DME, a clean-burning fuel
can be blended with LPG (South Korea has been seeking ways to increase LPG
consumption as an alternative to LNG)
used on its own as transportation fuel as an alternative of LNG , LPG and Diesel
gaining attention from automakers also as it is cheaper than LPG and produces
little pollution from combustion
Korea gas Corporation has announced a Roadmap of DME (Korea Gasnews, July
11 2012)
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DME has tremendous potential as an effective way to use the abundant natural gas DME generates significantly less carbon emissions Combustion produces extremely low levels of particulates and
nitrogen oxide DME can easily converted into liquid at a pressure of just 5 bar.
Handling is uncomplicated and resembles that of liquefied petroleum gas(LPG)
DME is injected as a liquid, so very similar fuel injector to diesel can be used and multi-point injection strategy can be applied
Unlike LNG, DME does not require cryogenic temperature; it is handled and stored like propane, with tank pressured of 75psi.
DME is nontoxic, already being used as an aerosol propellant in cosmetics and other household products
DME can be made from natural gas and bio-mass. When produced from biomass, DME can provide up to a 95% CO2 reduction compared to diesel(Oberon Fuels)
Year Nation Manufacturer Type/engine displacement Technology/specification
1996 Japan JFE Holdings (Japan) NKK Cargo truck, 4636 cc In-line pump
1998 Japan Isuzu Advanced Engineering Center,
Ministry of Land, Infrastructure and Transport (Japan) Medium-sized bus, 8226 cc Common-rail, 48 passengers
2000 Sweden Danish Technological Institute, Haldor Topsoe A/S, Statoil A/S, Volvo Truck & Bus Group (Sweden)
City bus, 9600 cc Common-rail type, DH10A engine, In-line 6 cylinder, Turbocharged
2001 Japan Mitsubishi, JOGMECa, Iwatani Int’ Corp (Japan) Cargo truck, 4214 cc Distribution pump
2002 Japan Isuzu (Japan) Medium-sized truck, 7166 cc In-line pump
2002 USA The Penn. State University,
Air Products and Chemicals (USA) Shuttle bus, 7300 cc
HEUIb, Navistar T444E engine (V-type 8 cylinder), Turbo diesel engine
2003 Japan Hino Motors, NEDCc (Japan) Hybrid bus, 7961 cc Common-rail 77 passengers
2004 Japan Isuzu (Japan) Cargo truck with crane, 4777 cc Common-rail
2004 Japan Nissan diesel, NTSELd (Japan) Large-sized cargo truck, 6925 cc In-line pump, w/DeNOx cat.
2005 China Shanghai Jiaotong Univ., Shanghai Automobile,
Shanghai Diesel (China) Shanghai city bus, 8300 cc In-line pump, Turbocharger, Inter-cooler
2005 Japan AISTe, JOGMEC (Japan) Medium duty truck, 7166 cc In-line pump, In-line 6 cylinder,
Natural aspiration
2006 Korea KIERf (Korea) Truck, 3 ton In-line pump
2006 Japan Nissan Diesel Motor, NTSEL (Japan) Heavy-duty truck, 6825 cc Jerk pump type, FE6T engine (Nissan), FE6T
engine (Nissan), In-line 6 cylinder, Turbocharger
2008 Korea KIER (Korea) Bus, 8071 cc In-line pump, 6 cylinder
2009 Korea Hanyang University (Korea) Passenger car, 1582 cc Common-rail, In-line 4 cylinder
2009 Korea KATECHg (Korea) SUV, 1991 cc Common-rail, EGR, VGT
2012 Sweden Volvo, Dreem, Chemrec Truck, 12800cc In-line 6 cylinder, DOC
a JOGMECD: Japan Oil, Gas and Metals National Corporation
b HEUI: Hydraulically actuated electronically controlled unit injectors
c NEDO: New Energy and Industrial Technology Development Organization
d NTSEL: National Traffic Safety and Environment Larboratory
e AIST: National Institute of Advanced Industrial Science and Technology
f KIER: Korea Institute of Advanced Industrial Scrience and Technology
g KATECH: Korea Automotive Technology Institute
h http://www.dme-vehicle.org/eng/index_eng.html
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In Europe, several countries have headed the development of DME-fueled vehicles
AVL(Austria) has promoted R&D of DME-fueled engines since 1995
Volvo trucks has completed more than 1.05million km of DME testing in Europe
Completion of two field trials with DME fueled vehicles, the 1st with a bus in
1999 and then with a truck in 2005
Item Specification
Engine type/cylinder number D13/ Inline 6
Capacity 328kW
Displacement volume 13L
Exhaust level EURO-5
Volvo : DME vehicle and engine
1998 – 2001,Development of DME HD truck using by mechanical fuel system(NissanDiesel,
MLIT, NTSEL)
Development of DME LD truck through empirical evaluations(Bosch Japan, NTSEL)
Developing of DME LD/MD truck according to unique common-rail tech.(ISUZU)
Developed some of the trucks, Performing a road test evaluation(Tokyo – Nigata)
DME charging station construction and its operation(Kawasaki, Yokohama, Nigita, etc)
<Field Test Area and Route of the Medium Duty DME Truck>
<Current situation of DME trucks and DME charging stations>
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Study Contents
Development of High Pressure Pump and Injection for DME Fuel
Development of Common-rail DME Fuel Supply System
Development of 2.9-liter Common-rail DME Engine
Evaluation of Power and Emission Performance for DME vehicle
Development of Common-rail DME Vehicles for meeting EURO-5
Field Test of the DME Vehicle
Development of CR DME Vehicles for Meeting EURO-5 Requirements
- About twice the DME fuel volume must be injected compared to diesel fuel, in order to ensure
the equivalent power output as diesel engine
0.187mm(inner dia.)
0.145mm(outer dia.)
0.295mm(inner dia.)
0.314mm(outer dia.)
0.286mm(inner dia.)
0.3mm(outer dia.)
10
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Nozzle Design of DME Injector Production of CR DME Injector Prototype
Design of Injection Nozzle and Needle using Nozzle Flow Model
Production of DME Injector Prototype by 3D Design and Numerical Analysis
Enlargement of DME flow rate
3D Design Hole cutting Nozzle-hole design(Type II) Nozzle-hole design(Type III & IV)
- Limit of increasing injection rate only by enlargement of nozzle hole (0.16mm0.25mm)
- Enlargement of orifice diameter in high pressure line leads to further increasing injection rate
Enlarging orifice diameter from 0.6mm to 1mm 191.9% increase of injection rate
Modification of Orifice hole
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Replacement of Elastomer Static Seal to HNBR(Hydrogenated Nitrile Butadiene Rubber)
- Addition of HNBR High Pressure Solenoid Sealing to prevent leakage and Corrosion
• Addition of Guide Adaptor made of HNBR
<HNBR Guide Adaptor >
<Addition of HNBR Solenoid Sealing >
HNBRSolenoid sealing
기존Solenoid sealing
개선된HNBR
Solenoid sealing
Leak, Response, Injection Rate, Fluctuation Rate of DME Injector
Pulsation of Fuel Pressure
Experimental Set-up Test Results of CR DME Injector
Leak test Injection quantity
Multi-injection(I) Multi-injection(II)
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Spray Visualization Experiment by Using High Pressure Chamber
Computational Fluid Dynamics –STAR-CD, KIVA –V3
15
Spray Development and Pattern Spray penetration length /Spray angle
Comparison of spray visualization test results with numerical analysis
Breakup and evaporation of DME droplet occur rapidly in the early period of injection
Momentum magnitude of droplet is directly related to the droplet break-up
The biggest spray angle in the nozzle-hole diameter 0.25 mm; excellent atomization characteristics
DME_Φ=0.166_Pinj70MPa_Pamb5MPa 0.4ms 0.8ms 1.2ms 1.6ms 2.0ms 2.4ms
DME_Φ=0.250_Pinj70MPa_Pamb5MPa 0.4ms 0.8ms 1.2ms 1.6ms 2.0ms 2.4ms 3.0ms
DME_Φ=0.300_Pinj70MPa_Pamb5MPa 0.4ms 0.8ms 1.2ms 1.6ms 2.0ms 2.4ms
0
20
40
60
80
Sp
ray
An
gle
[d
eg
ree
]
0 0.5 1 1.5 2 2.5 3 3.5After Start of Injection [ms]
0
20
40
60
Pe
ne
tra
tion
Len
gth
[mm
]
DME_0.300 mm_35 MPa
DME_0.300 mm_70 MPa
DME_0.250 mm_35 MPa
DME_0.250 mm_70 MPa
DME_0.166 mm_35 MPa
DME_0.166 mm_70 MPa
DME_0.300 mm_35 MPa
DME_0.300 mm_70 MPa
DME_0.250 mm_35 MPa
DME_0.250 mm_70 MPa
DME_0.166 mm_35 MPa
DME_0.166 mm_70 MPa
Injection
Delay
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3-dimensional,multi-phase, compressible, turbulent flow analysis with moving grid technique
Prediction of cavitation region and effective flow area for various nozzle geometries
DME causes much larger recirculation zone than Diesel, resulting in larger cavitation region
DME is much more sensitive to geometrical effect of injection nozzle on Internal flow
characteristics
Volume Fraction of Cavitation
Cavitation region (Section A-A’)
R-0
R-
0.08
DME Diesel
C f of DME & Diesel
① ②
③
④
⑤
⑥
A
A’
Recirculation zone ↓ Effective flow area ↑
Developed a new DME High Pressure Pump
1st DME High pressure pump (3L) 2nd DME High pressure pump (3L)
Type Eccentric cam Wobble plate
No. of plunger 2 5
Bore (mm) 9 10.5
Stroke (mm) 10 -
Flow rate (kg/h) 50@1,000 rpm 135@2,000 rpm
System pressure (bar) 600 500
Speed (rpm) 2,000 2,000
Photo
Feature
High-pressure and high-efficiency Very difficult to apply variable capacity Large size (but insufficient discharge flow)
High-pressure and high-efficiency Easy to apply variable capacity Small size (but sufficient discharge flow)
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Design of Wobble Plate Type HP Pump
Drawing
Components of DME Pump
Details of Components of DME pump
5 Plunger Wobble Plate Type Pump
- Ø10.5 Plungers, 12 mm Stroke, 5.2 cc/rev
Addition of Lubricity and Viscosity Index Improver
- Lubricity improver(LZ539M) 1,200 ppm + Viscosity index improver(Newpol V-10-C) 600 ppm
Good Cylinder Surface of Inner High Pressure Chamber
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Three-stage injection process
[Source : SAE Technical Paper No.2006-01-3324]
DME exhibits higher Nox emissions than Diesel due to the longer injection duration for Diesel
power equivalence
steep heat-release rate in the premixed combustion phase of single and multi-step injection
Rapid fuel evaporation reduces the period of the mixing-controlled combustion
Optimization of Injection Timing
Comparison of Injection timing of three-point injection strategy for Diesel & DME
- Three-stage injection(Pilot – Pre – Main) is very effective for reducing NOx at partial load
- Optimization of Injection Timing
Optimized Timing
※ NEDC mode driving range (1,200~2,200rpm, 2~6bar)
Pilot timing(˚CA ATDC) Pre timing(˚CA ATDC) Main timing(˚CA ATDC)
DME
Diesel
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Nox Emission Performance of CRDI DME Engine
- Comparison of Nox emission between DME and Diesel E/G
Optimized Injection Strategy can reduce Nox emission from NEDC by 68.5% compared to Diesel
NOx Emission Map
NOx Emission(ppm) by
DME
NOx Emission(ppm) by
Diesel
Specification of 3L Common-rail DME Prototype Engine
Installation of DME HP Pump Installation of CR DME Injector
Performance Test of DME Engine
Item Specification
Displacement Volume 2,902cc
Bore × Stroke 98 mm × 101.5mm
Compression Ratio 17.4 : 1
Idle speed 800 ± 10 rpm
Intake timing BTDC 26° / ABDC 50°
Exhaust timing BBDC 72° / ATDC 32°
Fuel system Common-rail direct injection
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Full load performance of DME engine equivalent to that of Diesel base engine
Maximum torque(22.5kgm) of the DME engine could equal to that of Diesel
Comparable thermal efficiency of DME engine to that of Diesel
DME Engine Performance
Engine Torque Thermal efficiency
Main Components for DME Fuel Supply System
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Development of DME fuelled Common-rail Passenger Van Modularization Design for Fuel Supply System is Applied
DME Low Pressure Pump DME Fuel Tank
Modularization Design of Fuel System
DME Common-rail Light-Duty Truck for EURO-5
Development of Fuel Supply System for Common-rail DME Light-Duty Vehicle Meeting Euro-5 Emission Regulation
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Performance & Emission Test
Road Test
NEDC mode Test
30
Emission Modal Data of CRDI DME Vehicle under NEDC Test Cycle
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As Results of Performance and Emission Tests,
- Meeting EURO-5 Emission Regulation for the First in Korea
- Best Performance : 125HP (Equivalent to Diesel Engine)
- Fuel Consumption rate(based on Vehicle) : 5.7km/L
THC+NOx (g/km)
CO (g/km)
NOx (g/km)
PM (g/km)
EURO-5 0.35 0.74 0.28 0.005
Base Diesel (EURO-4 )
0.366 0.147 0.324 0.023
CRDI DME Vehicle
0.343 0.061 0.181 0.003
Purpose
Building and operating DME refueling station in Chungju city
Field test of the DME vehicle on public road for reliability
Development of field evaluation technique
Ministry of Trade, Industry and Energy Republic of Korea
Period :
(2012.09 ~
2015.08)
Research Group : Korea Automotive Technology Institute, Ulsan University, Korea Gas Corporation
Korea Gas Safety Corporation, Korea National University of Transportation
One DME refueling station is planning to build up in Chungju city
The first operation on public roads was between KNU to Hoam Reservior
To date, the field test has involved 1 Passenger van, which have accumulated about 6,000km
No durability trouble of the injection pump was encountered
Korea National University of Transportation
Hoam Reservior
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Monitoring System Configuration
No. Parameter Name
1 EMS Program Control
Environment
2 Driving Information Control
System Environment
3 Navigation Information Control
data-logging Equipment
4 Calibration ECU BOX
5 Driving Imaging Device
6 Navigation location Logger
Monitoring data Sheet
<EMS Data Logging Env.>
<Monitoring Env.>
No. Parameter Name No. Parameter Name
1 RPM 7 Oil Temp.
2 Acc. Pedal Sinal 8 Intake Air Temp.
3 Pre inj. Time 9 Common Rail Temp.
4 Pilot Inj. Time 10 Compressor Press
5 Main Inj. Time 11 HP Pump IMV Duty
6 BMEP
No. Parameter Name No. Parameter Name
1 Coolant Temp. 14 DME LP Pump Outlet Press.
2~3 T/C inlet / outlet Temp. 15 DME Res. Tank Return Press.
4 Intercooler outlet Temp. 16 Monitoring Screen
5~8 Intake Manifold Temp. #1~#4 17 Position
9~12 Exh. Manifold Temp. #1~#4 18 Speed
13 DME LP Pump inlet Press. 19 Path and Distance
05. 1차년도 기술개발 연구결과
Time Synchronization of Data
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Data Analysis from Integrated Monitoring System
Time Synchronization of Data
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KATECH has successfully developed DME fuelled common-rail light-duty vehicle by
optimum modification and design of injector and high pressure pumps
corresponding to DME fuel.
ECU system has also developed for DME common-rail engine, plays a important
role in meeting tight regulation, EURO-5.
The common-rail DME vehicle for EURO-5 were successfully developed by
optimizing EGR rate, injection timing and duration.
A diagnostic method has been developed for monitoring DME vehicle. To date,
the field test has involved 1 Passenger van, which have accumulated about
6,000km
In future, much more high performance of injector and high pressure pump are
required with consideration of reliability and characteristics of DME fuel.
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In case of using bio-diesel as lubricant, friction parts of high pressure pump were easily
damaged due to harsh wear.
Long term storage of bio-diesel can cause problem of clogging DME fuel system
part photo cause
Low
pressure
parts
- Damaged bearing retainer
- Sever friction between plates causes many
metal chips inside the pump
piston - Scratch on the surface of piston occurring
in high load engine running condition
Check valve - Malfunctioning of check valve due to
incoming metal chips
DME exhibits higher Nox emissions than Diesel due to the longer injection duration for Diesel
power equivalence
steep heat-release rate in the premixed combustion phase of single and multi-step injection
Rapid fuel evaporation reduces the period of the mixing-controlled combustion
The latent heat from each DME injection is 2.4 times that from Diesel –fuel injection ( a
lower charge temperature at SOC under the same intake condition)
Shorter ignition delay results in reducing the rate of temperature rise in the premixed-
combustion phase
The evaporation rate for fuel drops in the DME spray is about 3 times that of Diesel fuel,
resulting in reducing the charge heterogeneity
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Damaged parts of the DME Injector due to friction and corrosion
-Corrosion of Needle parts, Contamination of Decompression chamber
Adhesion & Corrosion Contamination Breakage of Solenoid Sealing
Needle lift behavior - Slow opening of the nozzle; highly compressible
Pressure drop - Increasing pressure drop in the valve Seat - Reduction of the nozzle exit velocity
Pressure oscillations and residual pressure in the injection line - Pulsation occurs between fuel pump and injector
Flow phenomena and flow rate in the nozzle orifice - High fluid velocity, low static pressure - Expanded cone angle of nozzle exit
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분사율 평가 (디젤) DME 분사유량 평가
단순 노즐 홀 확경 (0.16mm0.25mm) 만으로는 400bar 이하 조건에서는 분사유량 증대 없음
분사율 평가를 통한 원인분석 결과, 인젝터 노즐 내부의 연료 공급 부족으로 니들 닫힘시기 빨라짐
고압측 오리피스 변경 결과(0.6mm1.0mm) 베이스 대비 191.9% 유량 개선
400 800 1200 16000
10
20
30
40
50
60
70
+60.2% In
jec
tio
n a
mo
un
t, m
inj (m
g/s
t)
teg
=1.0ms
Base(DIE)
Base (DME)
Type I (DME)
Type II (DME)
Type II 1.5mm (DME)
Type II 1.0mm (DME)
In
jec
tio
n a
mo
un
t, m
inj (m
g/s
t)
Injection pressure, Pinj
(bar)
Pamb
=20bar
+191.9%
-0.5 0.0 0.5 1.0 1.5 2.0 2.50
10
20
30
40
50
60
70 Type I
Type II
Type II 1.0mm
Type II 1.5mm
In
jec
tio
n r
ate
, Qinj (m
m3/m
s)
Time after start of injection, SOI (ms)
teg
=1.0ms
Pamb
=20bar
Pinj
=400bar
니들 닫힘시기 빨라짐
유량개선
DME 인젝터 노즐 설계 및 제작
HNBRSolenoid sealing
기존Solenoid sealing
개선된HNBR
Solenoid sealing
- 노즐 유동모델을 이용한 인젝터 노즐 설계, 3D 해석을 통한 설계 개선 및 보완
- DME 인젝터 시제품에 대한 문제점 분석
- HNBR 소재를 이용한 솔레노이드 Sealing 및 Flexible 리턴 호수 변경 완료
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DME 인젝터 홀 및 오리피스 변경으로 분사량 증가 확인
20 40 60 80 100 120 140 1600
20
40
60
80
100
Inje
ctio
n a
mount
[mg/s
t]
+60.2%
Pamb
: 2MPa, teng
: 1ms
Base(DIE)
Base (DME)
Type I (DME)
Type I 1.0mm (DME)
Type II (DME)
Type II 1.5mm (DME)
Type II 1.0mm (DME)
+191.9%
Injection pressure [MPa]
노즐과 오리피스를 확경시 기존의 Base인젝터의
분사량에 비해 최대 191.9%가 증가
(분사압 40MPa 기준)
모델 홀수[ea] 홀 직경[mm] 오리피스 직경[mm]
Base 7 0.125 0.6
Type-I 6 0.16 0.6
Type-I 6 0.16 1.0
Type-II 6 0.25 0.6
Type-II-1mm 6 0.25 1.0
Type-II-1.5mm 6 0.25 1.5
45
DME 실증 차량 DME 인젝터 신뢰성 기술 개발
- DME 실증 차량의 연료시스템은 프로토타입 개발품과 디젤시스템을 개량하여 사용
• 인젝터(솔레노이드 Seal 개량), 고압펌프(프로토타입 개발), 저압펌프(프로토타입 개발)
- 자동차부품연구원 내 주행 결과 인젝터 내부에서 DME연료 누출 확인
• 인젝터 바디와 솔레노이드 간의 결합 단차를 최소화하기 위한 Sealing (HNBR) 장착
<DME 가스 누출 경로> <인젝터 파손> <개발 인젝터 파손>
가스누출
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Optimum Injection Strategy is Applied
- Nox Emission can be reduced by Max. 68.5% in NEDC Mode(1,200~2,200rpm, 2~6bar)
Nox Emission Map for DME & Diesel
Diesel - NOx Emission DME - NOx Emission
시간에 따른 분무발달 및 분무형상 비교 분무해석과 가시화실험의 도달거리 비교
실험
실
험 해석
시간
0.1ms 0.5ms 1.0ms
실험
해
석 해석
시간
1.5ms 2.0ms 2.3ms
도달거리와 SMD 예측(Pinj 35MPa, Pamb 5MPa)
연료 공급압력이 증가하고, 분위기 압력이 낮을 수록 도달거리는 증가
DME 입자의 분열과 기화로 인한 모멘텀 감소 확인
해석을 통한 SMD측정으로 실제 DME입자의 분열 예측 가능
분무 초기 입자의 분열은 분무속도에 의한 영향력이 지배적
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Larger diameter plunger - Increasing DME requirements
Pumping stroke increase - Increasing requirements flow rate;
highly compressible
Cam profile or wobble plate angle change - Changing requirements DME requirements
pressure and flow rate
Special treatment of the plunger surface - Leak-Proof; low viscosity of DME
DME 고압연료펌프 사양 및 용량검토
DME 커먼레일시스템 적용을 위한 고압연료펌프 사양 및 용량 검토 완료
- 편심형 DME 고압펌프는 엔진속도 2500rpm 이상에서는 연료량 부족 현상 발생
대유량의 사판형 DME 고압펌프 개발
1st DME High Pressure Pump • 2 Plunger Eccentric Type Pump • Ø9.0 Plungers, 10 mm Stroke, 2nd DME High Pressure Pump • 5 Plunger Wobble Plate Type Pump • Ø10.5 Plungers, 12 mm Stroke, 5.2 cc/rev
0 1000 2000 3000 40000
20
40
60
80
100Ps = 12bar
AFT DME Pump (Pr=400bar)
ITV Duty 100%
DME P
ump (i
n Bench) DME Injector return (Predic.)
DME Injector (in Engine)
DME Pump (Pr=600bar)
DME Pump (Pr=400bar)
DME Injection (Pr=400 bar) - Exp.
Req. DME Pump (Pr=400 bar)
Flo
w r
ate
(kg
/h)
Engine speed(rpm)
2nd DME Pump (Pr=400bar)
ITV Duty 100%
