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内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Combus'on mode design with high efficiency and low emissions controlled by mixture stra'fica'on
and fuel reac'vity
Presented by Prof. Yao Mingfa State Key Laboratory of Engines (SKLE), Tianjin
University
Feb 25, 2015
Future Powertrain Conference 2015
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Tianjin University & SKLE • The first ins'tu'on of higher learning in the history of
modern Chinese educa'on. – The former establishment was Peiyang University – Founded on October 2, 1895
• One of the na'onal key universi'es directly under the Ministry of Educa'on of China.
• Loca%on: Tianjin: the third largest city of China,120 kilometers southeast away from Beijing
Beijing Tianjin
2
• State key laboratory of engines (SKLE)
– Founded in 1989, With a grant from China Government – The unique state key laboratory on engine research in
China – The most famous center in China on research and
educa'on in advanced engine technology – Extensive industrial and government funding
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Funding from government and industry • Projects supported by MOST
– ‘973’ Key Fundamental Research Plan of State-‐8 universi'es in china aZend this project, such Tsinghua Univ. Shanghai Jiaotong Univ. etc
• Prof. Su: chief scien'st. PCCI, LTC, HCCI, CAI, Fuel chemistry, par'culate forma'on from diesel • Prof. Shu : chief scien'st. Exhaust Heat Recovery of engines • Prof. Zhao: chief scien'st.
– ‘863’ Advanced New Technology Plan of State • Diesel development, GDI development, alterna've fuel engine, engine control, HV, EV
– Interna'onal collabora'on sponsored by MOST
• Projects supported by Na'onal Science Founda'on of China – Engine combus'on, aeertreatment, combus'on noise, control, alterna've fuel combus'on
• Interna'onal collabora'on project sponsored by the Foreign Expert Bureau of the Chinese State Council and Educa'on Ministry of China
– Some Key Technologies for the Development of Efficient and Clean Internal Combus'on Engines
– MIT, Madison, Berkeley, Brunel, London city univ. Loughborough, Lund, Karlsruhe,Waterloo, KAIST of Korea
• Projects supported by industrial corpora'on • Other projects supported by MOE, Tianjin government, etc
15/2/26 3
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Engine Research in SKLE • 16 Professors, 17 Associate Professors • 219 M.S and 97 Ph.D graduate students • More than 50 millions Yuan funding per year from government and industry
15/2/26 4
Fuel Tech. & combustion
Advanced engine combustion tech..
Emissions & Aftertreatment
Noise, vibration,
structure & lubrication
Exhaust Heat Recovery
Engine Control
• Wide range of advanced engines research is being carried out in SKLE
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Recent Research Highlights(1/2) • Fuel and fuel combus'on - Bio-‐fuel technology - Fuel physical and chemical characteriza'on - Fuel combus'on kine'cs - Alterna've fuel combus'on technology
• Diesel engine combus'on - Fuel spray & fuel-‐air mixture prepara'on - Mechanism of LTC - Compound technology for HCCI combus'on (MULINBUMP) - High-‐density, Low temperature combus'on (LTC) for diesel engine
• Gasoline engine combus'on – HCCI/CAI combus'on technology – GCI combus'on technology – Mechanism of pre-‐igni'on for down-‐sizing engine – GDI engine
15/2/26
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Recent Research Highlights(2/2) • Emissions forma'on and aeer-‐treatment
– Soot forma'on mechanism – Effects of PM on environment – SCR and PM filter, Lean DeNOx
• Noise, vibra'on, structure & lubrica'on – NVH technology – Engine structure and design
• Engine control technology – Diesel engine control – Gasoline engine control – HV/EV control strategy
• Exhaust heat recovery • Fuel cell 15/2/26 6
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Academic exchange and collaboration • InternaKonal team �
15/2/26
§ Series international conference on engine combustion/engine control/fuel cell �
§ Seminar �
7
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Student Activities
15/2/26
l More than 300 graduate students study in SKLE. Engineers from industry also aOend the summer school. �
8
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Outlines • Motivation • Effects of combustion model on engine performance and
emissions • Combustion model design fuelled with dual-fuel • Conclusions
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Challenges for HCCI combustion
• HCCI combustion has the potential to be highly efficient and to produce low emissions.
• However, controlling ignition timing is one of the challenges in the operation of HCCI engines
• Controlling combustion rate (how to enlarge the operating range) is another challenge in the attempt to take advantage of HCCI technique.
• It is also necessary to improve combustion efficiency and decrease high THC and CO emissions
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Effects of fuel properties on HCCI
• Fuel RON affect the efficiency • Fuel RON affect the opera'ng
range • Note: port-‐injec'on
Mingfa Yao Combus'on Science & Technology 2007, 179(12): 2539-‐2559
Mingfa Yao Energy & Fuels 2008, 22, 2207–2215
• Varying fuel RON can enlarge HCCI opera'on regions and get high thermal efficiency
– Low load-‐high cetane number fuel – High load-‐high octane number fuel
• It is difficult that one fuel meet both low load and high load demands 0.34
0.34
0.29
0.240.19
0.39
0.44
0.49
0 10 20 30 40 50 60 70 80 902.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
Knocking Limit
0.54
0 10 20 30 40 50 60 70 80 902.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0n=1400 / r/min IMEP / Mpa
0 10 20 30 40 50 60 70 80 902.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
λ fuel
RON
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
HCCI controlled by charge stratification
• Port injec'on + Direct injec'on, PI/DI ra'o and 'ming affect the charge stra'fica'on
• HC decrease, CO and NOx increase for stra'fica'on
Mingfa Yao Fuel 88 (2009) 354–365
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Mixture reactivity enlarges HCCI operation range
• Dual fuel by port injec'on: High cetane fuel + high octane fuel
• Change mixture reac'vity by dual fuel ra'o, then control HCCI combus'on processes
• By using DME/methanol dual fuel, HCCI can be operated over a fairly wide engine speed and load range
Mingfa Yao Fuel 85 (2006) 2046–2056
0.540.48
0.420.37
0.320.27
0.25
0.230.21
4 6 8 10 12 14 16 18 20 22 24
4
5
6
7
8
9
1400 r/min IMEP/MPa
Partial Burn
Knocking LimitDM
E E
xces
s A
ir R
atio
λD
ME
Methanol Excess Air Ratio λMEOH
0.740.65
0.59
1000 1200 1400 1600 1800 2000 22000.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
IMEP
(MPa
)
Engine Speed(r/min)
DME DME+CNG DME+MeOH
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
DME Port injection + Methanol Direct Injection
-40 -20 0 20 40 60 80 100
0
50
100
150
200
0
2
4
6
8
10
12
Crank Angle /deg.C
ylin
der P
ress
ure
/Mpa
Hea
t Rel
ease
Rat
e /
J.C
AD
-1
DME%=29.4DME%=21.0DME%=17.0DME%=12.0DME%=10.4
n=1400r/minImep=0.84Mpa
DME%=29.4DME%=21.0DME%=17.0DME%=12.0DME%=10.4
Compound combusKon: HCCI:(LTR of DME+HTR of DME)+Diffusion combusKon (Heat release of Methanol) Engine can work in full load mode, low HC and CO emissions, NOx emission can be controlled by methanol injec'on strategy
-70 -60 -50 -40 -30 -20 -10 0
0
500
1000
1500
2000
2500
喷 射 时 刻 / οCA ATDC
φMEOH=0.5 φMEOH=0.338 φMEOH=0.119
N
OX
排放
/ ppm
爆 震
部 分 燃 烧
Reactivity + charge stratification
Mingfa Yao, Energy Fuels, 2009, 23 (5), 2719–2730
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Motivation & objective • Wisconsin, SAE 2009-‐01-‐1442
– No tradi'onal PM/NOx tradeoff – Approach 2010 EPA HD truck emission
standards in-‐cylinder at 11 and 6 bar net IMEP
– Low ISFC and MPRR – Tradi'onally DI or SI for full load
• It is poten'al to achieve high thermal efficiency for gasoline/diesel dual-‐fuel
• If the dual fuel can be used to control combus2on, how to op2mize the combus2on in full load range? Especially, diesel/CNG or diesel/methanol dual fuel.
Source from Reiz
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Outlines • Motivation • Effects of combustion model on engine performance and
emissions • Combustion model design fuelled with dual-fuel • Conclusions
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Effects of combustion mode on performance and emissions
• Test fuel: diesel (20%) + gasoline (80%) • CombusKon mode: (HPCC-‐Highly Premixed Charge CombusKon)
– E-‐HPCC: 20% diesel early direct injecKon + 80% gasoline port injecKon – L-‐HPCC: 20% diesel late direct injecKon + 80% gasoline port injecKon – LTC: 20%diesel +80% gasoline mixture direct injecKon
• Heat release control: the same CA50, CA50=8CA ATDC • Cycle fuel: 50mg; engine speed: 1500r/min
-50 -40 -30 -20 -10
0
2
4
6
8
10
Early injection
SOI (° ATDC)
CA
50 (°
ATD
C)
Late injection
EGR=40%
E-‐HPCC L-‐HPCC
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Stratification & reactivity for early or late injection
Diesel SOI
Reac'vity
Stra'fica'on
Early-‐ injec'on
Late-‐ injec'on
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Indicated Thermal Efficiency
30 35 40 45 5040
42
44
46
48
50
Indi
cate
d Th
erm
al E
ffici
ency
[%]
EGR [%]
E-HPCC L-HPCC LTC
The three combustion modes have little difference in indicated thermal efficiency
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Thermal Efficiency Analysis (1)
30 35 40 45 50400
420
440
460
480
500
Exha
ust T
empe
ratu
re [℃]
EGR [%]
E-HPCC L-HPCC LTC
The exhaust temperature of LTC is highest, resulting in the highest exhaust heat
Exhaust heat can be recovered by Turbo-charger
30 35 40 45 5090
92
94
96
98
100
Com
bust
ion
Effic
ienc
y [
%]
EGR [%]
E-HPCC L-HPCC LTC
E-HPCC and L-HPCC combustion efficiencies are almost the same, it indicates that the port injection of gasoline go into the quench area and can not be burned completely The combustion efficiency of LTC is higher than the other two combustion modes
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Thermal Efficiency Analysis (2)
0
10
20
30
40
50
Perc
ent F
uel E
nerg
y
E-HPCC L-HPCC LTC
Gross Ind.Efficiency
Heat TransferExhaust Comb. Loss
44.1 44.6 44.2
35.136.8 37.8
17.114.9
16.8
3.8 3.71.2
The exhaust heat of LTC is the highest
The heat transfer of L-‐HPCC is the lowest
The combus'on efficiency of E-‐HPCC and L-‐HPCC is lower than LTC
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
NOX & soot Emissions
30 35 40 45 500.0
0.2
0.4
0.6
0.8
1.0
soot
[10
-2g/
kWh]
EGR [%]
E-HPCC L-HPCC LTC
NOX emission of L-‐HPCC and LTC could be reduced drama'cally by EGR E-‐HPCC mode can aZain ultra-‐low NOX emission which is insensi've to EGR
Three combus'on modes bring in a smokeless way in spite of EGR Early port injec'on of 80% gasoline and long igni'on delay of fuel make the soot emission low enough to meet stringent legisla'on
NOX of E-HPCC is not sensitive to EGR 30 35 40 45 50
0.0
0.5
1.0
1.5
2.0
2.5
3.0IS
NO
X [g/k
Wh]
EGR [%]
E-HPCC L-HPCC LTC
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Combustion Analysis by CFD
CA10(diesel)
E-HPCC
L-HPCC
LTC
CA50(Temp.) E-HPCC
L-HPCC
LTC
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Summary • LTC fuelled with blended-‐fuel with 80% gasoline and 20% diesel
– Highest heat release rate, highest MPRR – Lowest HC emissions, highest combus'on efficiency – CO and NOx emissions strongly depend on EGR ra'o
• E-‐HPCC – Lowest NOx and soot emissions, in-‐sensi've to EGR, mainly from upper piston
areas – Lowest exhaust temperature – EGR can enlarge the opera'on region – Soot can be generated from the impingment fuel (depending on injected fuel,
injec'on 'ming, EGR ra'o)
• L-‐HPCC – Lowest heat release rate, lowest MPRR – NOx emissions depend on EGR, but CO is insensi've to EGR except high EGR ra'o – NOx and soot emissions are mainly formed in diesel spray region – Poten'al in high and full load mode
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Outlines • Motivation • Effects of combustion model on engine performance and
emissions • Combustion model design fuelled with dual-fuel • Conclusions
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Combustion characteristics fuelled with dual-fuel • Flexible fuel and mixture
prepara'on – Port injec'on/DI injec'on – High octane fuel + high cetane fuel
• Combus'on was controlled by stra'fica'on & mixture reac'vity – Fuel (mixture) reactivity control – Fuel stratification (injection strategy) – Combustion model design
Fuel with high octane number
Fuel with high cetane number
Diesel SOI
Single injec'on
Reac'vity Stra'fica'on for diesel
Double injec'on
Reac'vity Diesel SOI2
First injec'on (SOI1): early injec'on, reac'vity
Stra'fica'on for diesel
Small load Reac'vity
Stra'fica'on for diesel
High load
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Combustion mode design fuelled with dual-fuel
• Large & full load combusKon – CI (High CR) or SI (Low CR) – VVT+LTC(High cetane fuel) or VVT+PPC
(high octane fuel) – Diesel ignites gasoline (Late diesel
injec'on, L-‐HPCC)-‐ QHCCI
Hybrid combustion mode design:
• Small load combustion - Diesel (high cetane fuel) PCCI (LTC) - VVT+GCI (high octane fuel) - Diesel and gasoline dual fuel
• Middle load combustion • Diesel and gasoline dual fuel: diesel early
injection, high gasoline ratio (E-HPCC)
Flexible fuel Flexible combusKon mode
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Combustion mode design fuelled with dual-fuel
• Small load-‐ – Diesel PCCI/LTC
• Middle load – Diesel/gasoline dual-‐fuel HCCI: diesel early-‐injec'on or double-‐injec'on(early SOI2)
• High load & Full load – Diesel/gasoline dual-‐fuel QHCCI: diesel double –injec'on (late SOI2)
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Combustion optimization • CombusKon control parameters
– Gasoline/diesel ra'o – Diesel injec'on strategy – EGR ra'o
• OperaKon region limit – MPRR<1.0MPa/CA (Knocking limit) – COVimep<5% (misfire limit) – NOx<0.4g/kW.h (NOx limit) – Smoke opacity<5% (Smoke limit)
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Diesel/gasoline dual-fuel: diesel injection strategy Combus'on Control -‐ The same main combus'on posi'on (CA50
control) -‐ The same Rg, EGR ra'o, SOI1, injec'on fuel -‐ E-‐SOI2: longer igni'on delay, well-‐premixed -‐ L-‐SOI2: shorter igni'on delay, stra'fica'on
-50 -40 -30 -20 -10 00
2
4
6
8
10
12SOI1=-55(°CA ATDC)
SO2/(°CA ATDC)
CA
50/(
°CA
ATD
C)
SOI2
Early-‐ SOI2 Late-‐ SOI2
-30 -20 -10 0 10 20 300
2
4
6
8
10
12
0
100
200
300
Com
bust
ion
Pres
sure
/MPa
Crank Angle/(°CA ATDC)
CA50: 6°CA ATDC L-SOI2 E-SOI2 Single
Hea
t Rel
ease
Rat
e/(J
/°C
A)
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE) -‐31-‐
• High EGR rate is required for reducing the NOx emissions, especially for L-‐SOI2.
30 35 40 450.00.20.40.60.8
1761781801821841860
-20-40-60-80
0.000.02
0.10So
ot/(g
/kW·h)
L-SOI2 E-SOI2 Single
EGR/%
0
2
4
6
CO/(g
/kW·h)
2
4
6
8
THC/
(g/k
W·h)
0.30.60.91.21.5
M
PRR/
(MPa
/°CA)
NOx/
(g/k
W·h)
ISFC
/(g/k
W·h)
SOI2
/(°CA
ATD
C)
• L-‐SOI2: the lowest maximum heat release, two stages HTHR, longest combusKon duraKon – the charge is more straKficaKon
for L-‐SOI2 than E-‐single and E-‐SOI2
– More straKficaKon, more sensiKve to EGR for NOx emissions
Diesel/gasoline dual-fuel: diesel injection strategy
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Double injection strategy
SOI1: the first injection fuel improves the mixture reactivity, more early injection, more homogeneous mixture. It is necessary to improve the reactivity for second injection ignition.
SOI2: the second injec'on fuel will trigger the combus'on because of the stra'fica'on。
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Extend operation by late-SOI2
0
20
40
60
80
柴油喷油量 (mg/cycle)
柴油
汽油
8 10 12
808386899295
140120100
汽油比例
(%)
总喷油量
(mg/
cycl
e)
80
喷油压力 (MPa)1.1
1.2
1.3
1.4
0.6
0.8
1.0
1.2
IMEP
(MPa
)
MPR
R (M
Pa/°
)
EGR/% 45
SOI1/°ATDC -55
Mass of diesel /(mg/cycle) 8,10,12
CA50/°ATDC 8~9
Injection pressure/MPa 80,100,120,140
• Improve injec'on pressure (140MPa, Max IMEP=1.39 MPa) – More homogeneous mixture – Improve gasoline ra'o, but it is
necessary to inject enough diesel for improving combus'on stability.
• Opera'on range was limited by soot emission, how to decrease soot emission?
• Fuel physics properity (improve mixture)
• Oxygen fuel ? • VVA-‐ delay intake valve closing 'ming • ……
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Compare operation range of different injection strategies
0.91.01.11.21.31.41.5
最大
IMEP
(MPa
)
E-Single E-SOI2 L-SOI2
1.0
1.1
1.2
1.3
MPR
R(M
Pa/°
CA
)
0.0000.0010.0020.0030.0040.005
Soot(g
/(kW·h
))
170
175
180
185
ISFC(g
/(kW·h
))
l Max IMEP and it’s constraint factor: • E-‐single:1.026 Mpa,High MPRR & pressure • E-‐SOI2:1.027 Mpa,High MPRR & pressure • L-‐SOI2:1.391 Mpa,High soot emission
Injection strategy E-single E-SOI2 L-SOI2
SOI1/°ATDC -58 -55
SOI2/°ATDC -35 -31 -8
EGR/% 42.5 42.5 42.5
Gasoline /% 81.7 81.3 87.5
Injection pressure /MPa 80 80 140
soot(g/(kW·h)) 0.0014 0.0024 0.005 NOx/(g/(kW·h)) 0.17 0.21 0.11
CO/(g/(kW·h)) 3.17 3.35 7.09
THC/(g/(kW·h)) 3.78 4.14 4.07
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Effects of CN of DI fuel
0.05
0.10
0.15
0
1
2
3
4
2468
1012
-100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0468101214
CN34 CN43 CN56 CN100
SOI (°CA ATDC)
smok
e (F
SN)
NO
x (g
/kw
.h)
HC
(g/k
w.h
)
CO
(g/k
w.h
)
456789
4445464748
15
20
25
30
-100 -90 -80 -70 -60 -50 -40 -30 -20 -10 020
30
40
50
60
CN34 CN43 CN56 CN100
MPR
R (b
ar/°
CA
)
Indi
cate
d ef
ficie
ncy
(%)
Com
bust
ion
Dur
atio
n (°
CA
)
EGR
(%)
SOI (°CA ATDC)
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
0.100.09
0.13
0.15
0.08
0.170.19
0.090.10
0.12
0.13
0.16
0.080.07
0.06
0.110.13
0.21
0.29
0.086
0.54
0.70
0.076
0.79
0.95
0.066
1.0
1.1
0.055 1.2
0.10
0.12
0.08
0.170.21
0.06
0.29
0.050.040.37
72
76
80
84
88
92
Rg
(%)
72
76
80
84
88
92
Rg
(%)
knocking limitmissing fire limit
NOx ( g/kwh) --1700rpm;inj.pres.=80MPa
-65 -60 -55 -50 -45 -40 -35 -3072
76
80
84
88
92
NOx limit smoke limitmissing fire limit
Diesel SOI (°CA ATDC)
Rg
(%)
72
76
80
84
88
92
Rg
(%)
knocking limitmissing fire limit
EGR=0
EGR=40%
EGR=50%
EGR=60%
knocking limit smoke limitmissing fire limit
7.8
7.3 6.4
5.5
3.7
2.8
2.3
1.9
1.7
1.4
1.41.3
1.71.9
1.2
1.3
1.2
1.1
3.5
3.1
2.7 2.01.1
0.90
0.57
0.52
7.56.9
6.2
5.6
4.4 3.7
3.1
2.5
2.01.5
1.2
1.5
0.9 0.8
0.7
3.37
2.932.61
2.28
1.84
1.400.97
0.75
0.53 0.42
0.34
-65 -60 -55 -50 -45 -40 -35 -3072
76
80
84
88
92
NOx limit smoke limitmissing fire limit
Diesel SOI (°CA ATDC)
Rg
(%)
72
76
80
84
88
92
knocking limitmissing fire limit
knocking limitmissing fire limit
Rg
(%)
72
76
80
84
88
92
knocking limit smoke limitmissing fire limit
opacity N (%)--1700rpm;inj.pres.=80MPa
Rg
(%)
72
76
80
84
88
92
EGR=0
EGR=40%
EGR=50%
EGR=60%
Rg
(%)
178.1
177.3177.3
178.1
175.9175.5
175.0174.6
174.2
175.5
174.9
174.1
176.1
175.5
173.8173.5
173.2
173.1
172.9
173.8
172.8
173.5
173.0
174.0
174.2
174.5
174.8
172.7
172.4
172.2
171.9
175.2
174.6174.1
173.5
172.7
172.3
172.1
172.1
-65 -60 -55 -50 -45 -40 -35 -3072
76
80
84
88
92
NOx limit smoke limit missing fire limit
ISFC (g/kWh)--1700rpm;inj.pres.=80MPa
Diesel SOI (°CA ATDC)
Rg
(%)
72
76
80
84
88
92
knocking limit smoke limitmissing fire limit
Rg
(%)
72
76
80
84
88
92
EGR=0
EGR=40%
EGR=50%
EGR=60%
Rg
(%)
72
76
80
84
88
92
knocking limit missing fire limit
knocking limitmissing fire limit
Rg
(%)
Best ITE
There are a wide high efficiency range with ultra-‐low NOx and smoke
Lowest NOx
Lowest smoke
Combustion optimization
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
230
240
250
260
270
280
290
266262 .45
258 .89
2 75
268. 22 72
2 65. 8
28 3
2 87. 6
con
vent
ional
diese
l co
mbus
tion
HPCC
Dou
ble i
nject
ion
HPC
C Si
ngle
inje
ction
PCCI
Dou
ble i
nject
ion
PCCI
Sin
gle i
njec
tion
BSF
C/(g
/kW⋅h
)
Combustion modes
OEMw/o EGR
H ig h-p re ssureEGR
Lo w-press ureEGR
PCC
I Dou
ble i
njec
tion
PCC
I Sing
le inj
ectio
n
HPC
C Dou
ble i
njec
tion
HPC
C Si
ngle
inje
ction
19 00 r/min, 0 .2 5MPa BMEP
Combustion modes comparison under the low load condition(CR=17.5) PCCI Pinj=1200bar, HPCCP inj=800bar
Combustion mode design in a 4-cylinder engine
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Higher efficiency than diesel engine without Nox control
320290260245
230
223
217
211
350
208
208
380 410
230
50
100
150
200
250
300
350
90kW80kW70kW60kW
50kW40kW30kWTo
rque£N̈¡¤m£©
20kW
100012001400160018002000220024002600280030003200
CR14+FG100Ó ÐÐ §Ó ͺ Ä ÊÍ òÓ ÐÌ ØÐ Ô
Speed£ r̈/min£ ©
BSFC (g/kW.h)
BMEP<0.5MPa PCCI-diesel fuel (diesel early injection with heavy EGR) BMEP=0.5~1.1MPa Diesel-gasoline dual fuel HCCI (diesel early injection) BMEP>1.1MPa QHCCI (diesel late injection near TDC)
Hybrid combustion control�
diameter 96 mm
stroke 103 mm
Cylinder number 4
displacement 2.982L
Compression ratio 14.0
Rated power 95 kW
Rated speed 3200 r/min
Maximum torque 340N·m
Max. torque speed ≤2400 r/min
Engine specifications �
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Ultra-low NOx & Soot emissions
39
NOx emissions (g/kW.h)
Soot emission (FSN)
• Ultra-low NOx & Soot emissions with high efficiency can be achieved. In order to meet Euro VI emission regulation, does gasoline-tank replace urea-tank?
• For engine map, it includes different combustion modes. High efficiency & ultra-low emissions can be achieved by combustion mode design.
• It can be operated different fuels with high-octane and high-cetane fuel, such as bio-diesel, n-butane, natural gas, methanol, ethanol, DME etc.
1.01.00.80
0.400.30 0.20
0.20
0.30
0.40
0.40
0.10
0.80 0.80
1.01.0
1.0
1.0
0.10
0.40
0.300.30
0.300.30
0.10
0.30
0.20
0.4
0.6
0.8
1.0
1.2
1.4
90kW
80kW
70kW
60kW
50kW
40kW
30kW
BMEP(MPa)
20kW
NOx(g/kW⋅h)
1200 1600 2000 2400 2800 3200
Speed(r/min)
0.02
0.02
0.020.050.1
0.2
0.05
0.4
0
0.1
0.6
0.05
0.7
0.2
00
0.4
0.1
0.4
0.2
0
01200 1600 2000 2400 2800 3200
0.4
0.6
0.8
1.0
1.2
1.4
90kW
80kW
70kW
60kW
50kW
40kW
30kWBMEP(
MPa)
20kW
Speed(r/min)
Smoke(FSN)
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
1000 1200 1400 1600 1800 2000
4
6
8
10
12
14
16
18平均有效压力/bar
转速/rpm
31.90
33.51
35.11
36.72
38.33
39.93
41.54
43.14
1000 1200 1400 1600 1800 2000
4
6
8
10
12
14
16
18
平均有效压力/bar
转速/rpm
31.90
33.51
35.11
36.72
38.33
39.93
41.54
43.14>45%
Diesel engine
46.58%
Methanol/diesel dualfuel
Compared the BTE of diesel and methanol/diesel dual fuel
Results From: Prof. Yao Chunde, SKLE, Tianjin University
40
43%
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Outlines • Motivation • Effects of combustion model on engine performance and
emissions • Combustion model design fuelled with dual-fuel • Conclusions
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Conclusions • Dual fuel combus'on is essen'ally controlled by mixture
stra'fica'on and reac'vity, different combus'on mode can be achieved by controlling injec'on strategy, dual fuel ra'o and EGR
• Smart combus'on mode (hybrid combus'on) can be achieved by dual-‐fuel to get high efficiency with ultra-‐low NOx and Soot emissions. Combustion design strategy: – Idle & low load mode: PCCI with high cetane fuel + VVT (early intake valve
close timing) +EGR – Small to middle/high (BMEP=1.2MPa) load mode: RCCI with dual fuel
+EGR – High/full load mode: PPC with high octane fuel + VVT (retard intake valve
close timing, miller cycle) + EGR • Combus'on mode design will be first applied in alterna've fuels,
such as natural gas, methanol etc. VVT system is another important control parameter for combus'on mode design.
内燃机燃烧学国家重点实验室 State Key Laboratory of Engines (SKLE)
Thanks for your attention!