Path to High Efficiency Gasoline Engine · 1 Prof. Bengt Johansson Division of Combustion Engines....
Transcript of Path to High Efficiency Gasoline Engine · 1 Prof. Bengt Johansson Division of Combustion Engines....
1
Prof. Bengt Johansson
Division of Combustion EnginesDepartment of Energy Sciences
Lund University
SI HCCI PPC
Path to High Efficiency Gasoline Engine
2
Scania diesel engine running on gasoline
0 2 4 6 8 10 12 1420
25
30
35
40
45
50
55
60
Gross IMEP [bar]
Gro
ss In
dica
ted
Effi
cien
cy [%
]
Group 3, 1300 [rpm]
FR47333CVXFR47334CVXFR47336CVX
!
ηi=57% = Isfc =147 g/kWh (@43 MJ/kg heating value)
Outline
• HCCI and fuel efficiency– 50% thermal efficiency
• Partially premixed combustion, PPC– Background
– Why gasoline is the best diesel engine fuel
– 56% thermal efficiency in car size engine
– 57% thermal efficiency in truck size engine
– Why 55% thermal efficiency is better than 57%
– How to reach 26 bar IMEP with US10 NOx, PM, HC and CO engine out
3
Outline
• HCCI and fuel efficiency– 50% thermal efficiency
• Partially premixed combustion, PPC– Background
– Why gasoline is the best diesel engine fuel
– 56% thermal efficiency in car size engine
– 57% thermal efficiency in truck size engine
– Why 55% thermal efficiency is better than 57%
– How to reach 26 bar IMEP with US10 NOx, PM, HC and CO engine out
4
Efficiencies?
5
Energy flow in an IC engineFuelMEP
QhrMEP
IMEPgross
lMEPnet
BMEP
QemisMEP
QlossMEP
QhtMEP
QexhMEP
PMEP
FMEP
Combustion efficiency
Thermodynamic efficiency
Gas exchange efficiency
Mechanical efficiency
Net Indicated efficiency
Brake efficiency
Gross Indicated efficiency
FuelMEP
QhrMEP
IMEPgross
lMEPnet
BMEP
QemisMEP
QlossMEP
QhtMEP
QexhMEP
PMEP
FMEP
Combustion efficiency
Thermodynamic efficiency
Gas exchange efficiency
Mechanical efficiency
Net Indicated efficiency
Brake efficiency
Gross Indicated efficiency
ηηηηη MechanicaleGasExchangmicThermodynaCombustionBrake***=
7
Thermodynamic efficiencySaab SVC variable compression ratio, VCR, HCCI, Rc=10:1-30:1; General Motors L850 “World engine”, HCCI, Rc=18:1, SI, Rc=18:1, SI, Rc=9.5:1 (std) Scania D12 Heavy duty diesel engine, HCCI, Rc=18:1;
Fuel: US regular Gasoline
SAE2006-01-0205
All four efficiencies
8
Problem with HCCI: Too fast combustion
9
Phasing HCCI combustion late helps burn rate but reduce ηC
10Magnus Christensen Ph.D. thesis 2002
Outline
• HCCI and fuel efficiency– 50% thermal efficiency
• Partially premixed combustion, PPC– Background
– Why gasoline is the best diesel engine fuel
– 56% thermal efficiency in car size engine
– 57% thermal efficiency in truck size engine
– Why 55% thermal efficiency is better than 57%
– How to reach 26 bar IMEP with US10 NOx, PM, HC and CO engine out
11
BackgroundCombustion concepts
Spark Ignition (SI) engine (Gasoline,
Otto)
Compression Ignition (CI) engine (Diesel)
Homogeneous Charge Compression Ignition
(HCCI)
Partially premixed combustion (PPC)
Diesel HCCI
Spark Assisted Compression Ignition
(SACI)Gasoline HCCI
+ High efficiency
+ Ultra low NOx
-Combustion control
-Power density
+ Clean with 3-way Catalyst
- Poor low & part load efficiency
+ High efficiency- Emissions of NOx and
soot
+ Injection controlled- Less emissions
advantage
Partially Premixed Combustion, PPC
13
-180 -160 -140 -120 -100 -80 -60 -40 -20
1000
2000
3000
4000
5000
6000p y
HC
[pp
m]
SOI [ATDC]-180 -160 -140 -120 -100 -80 -60 -40 -20
200
400
600
800
1000
1200
NO
x [p
pm]
Def: region between truly homogeneous combustion, HCCI, and diffusion controlled combustion, diesel
HCCI
PPC
CIPCCI
PPC: Effect of EGR with diesel fuel
14
Load 8 bar IMEP
Abs. Inlet Pressure 2.5 bar
Engine Speed 1090 rpm
Swirl Ratio 1.7
Compression Ratio 12.4:1 (Low)
DEER2005
Scania D12 single cylinder
1
43
2
Lund/Delphi/Volvo PPC Project
16
NOx <0.3 g/kWhPM < 2 FSN usingSwedish MK1 diesel fuel
Volvo D13 Multi-cylinder engine
Adapted fromSAE paper 2009-01-1127
Outline
• HCCI and fuel efficiency– 50% thermal efficiency
• Partially premixed combustion, PPC– Background
– Why gasoline is the best diesel engine fuel
– 56% thermal efficiency in car size engine
– 57% thermal efficiency in truck size engine
– Why 55% thermal efficiency is better than 57%
– How to reach 26 bar IMEP with US10 NOx, PM, HC and CO engine out
17
18
PPC with low cetane diesel
Lic. Thesis by Henrik Nordgren 2005 and presented at DEER2005
Outline
• HCCI and fuel efficiency– 50% thermal efficiency
• Partially premixed combustion, PPC– Background
– Why gasoline is the best diesel engine fuel
– 56% thermal efficiency in car size engine
– 57% thermal efficiency in truck size engine
– Why 55% thermal efficiency is better than 57%
– How to reach 26 bar IMEP with US10 NOx, PM, HC and CO engine out
19
20
VOLVO D5 with Gasoline
-80 -60 -40 -20 0 20 400
50
100
150
CAD [TDC]
Cyl Pressure [bar]Inj Signal [a.u.]RoHR [J/CAD]
N 2000 [rpm]
IMEPg 13.38 [bar]
Pin 2.57 [bar]
Tin 354 [K]
EGR 39 [%]
lambda 1.75 [-]
Injection SOI [TDC] Fuel MEP [bar] Percentage [%]
1 -64.00 10.88 41.28
2 -29.20 7.74 29.36
3 0.80 7.74 29.36
Load NoiseLoad & CA50
21
Efficiencies & Emissions
Indicated Gross Thermal Combustion/240
42
44
46
48
50
52
54
56
58
60
Effi
cien
cy [%
]
91 %
NOx*100 [g/kWh] CO [g/kWh] HC [g/kWh] Soot [FSN]0
5
10
15
20
25
30
35
40
Em
issi
ons
BelowDetectableLevel
13 ppm
0.46 %
4598 ppm
! D60 project goal
dPmax 7.20 [bar/CAD]
CA5 3.40 [TDC]
ID -1.00 [CAD]
CA50 11.35 [TDC]
CA90-10 13.00 [CAD]
Burn rate and ηT
22
Optimum Thermodynamic efficiency
Premixedness
High heat losses
Low effective expansion ratio
-80 -60 -40 -20 0 20 400
50
100
150
CAD [TDC]
Cyl Pressure [bar]Inj Signal [a.u.]RoHR [J/CAD]
Outline
• HCCI and fuel efficiency– 50% thermal efficiency
• Partially premixed combustion, PPC– Background
– Why gasoline is the best diesel engine fuel
– 56% thermal efficiency in car size engine
– 57% thermal efficiency in truck size engine
– Why 55% thermal efficiency is better than 57%
– How to reach 26 bar IMEP with US10 NOx, PM, HC and CO engine out
23
242424
Experimental setup, Scania D12Bosch Common RailPrailmax 1600 [bar]
Orifices 8 [-]
Orifice Diameter 0.18 [mm]
Umbrella Angle 120 [deg]
Engine / Dyno SpecBMEPmax 15 [bar]
Vd 1951 [cm3]
Swirl ratio 2.9 [-]
Fuel: Gasoline or Ethanol
2525
rc: 17.1:1rc: 14.3:1
Low Compression Ratio PPC High Compression Ratio PPC
Two Test Series: High & Low Compression Ratio
26262626
Fuel amount in the pilot is a function of:1.rc2.RON/MON3.EGR
-60 -50 -40 -30 -20 -10 0 100
0.2
0.4
0.6
0.8
1
CAD [TDC]
[a.u
.]
Load & CA50Const.
It must not react during compression
Injection StrategyIt consists of two injections. The first one is placed @ -60 TDC to create a homogeneous mixture while the second around TDC. The stratification created by the second injection triggers the combustion. The first injection must not react during the compression stroke, this is achieved by using EGR.
SAE 2009-01-0944
2727
IMEP sweep @ 1300 [rpm]EGR ~ const throughout the sweep, 40-50 [%]λ~ const throughout the sweep, 1.5-1.6 [-]Tin = 308 [K]
Standard piston bowl, rc: 17:1
High Compression Ratio PPC
SAE 2009-01-2668
28
Running Conditions
4 5 6 7 8 9 10 11 12 131.5
1.75
2
2.25
2.5
Gross IMEP [bar]
[bar
]
4 5 6 7 8 9 10 11 12 130
50
100
150
200
250
300
350
[C]Inlet Pressure
Exhaust Pressure
Inlet TemperatureExhaust Temperature
4 5 6 7 8 9 10 11 12 131.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2
Gross IMEP [bar]
λ [-]
4 5 6 7 8 9 10 11 12 1330
35
40
45
50
55
60
EG
R [%
]
2929
Efficiencies
4 5 6 7 8 9 10 11 12 1350
55
60
65
70
75
80
85
90
95
100
Gross IMEP [bar]
[%] Combustion Efficiency
Thermal EfficiencyGas Exchange EfficiencyMechanical Efficiency
3030
2 4 6 8 10 12 1430
35
40
45
50
55
60
Gross IMEP [bar]
[%]
Gross Ind. EfficiencyNet Ind. EfficiencyBrake Efficiency
Efficiency
57%
Too much heat transferToo much rate controlled combustion
312 4 6 8 10 12 14
0
2
4
6
8
10
12
14
16
18
Gross IMEP [bar]
CO
[g/k
Wh]
GrossNetBrakeEU VIUS 10
2 4 6 8 10 12 140
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
Sm
oke
[FS
N]
Gross IMEP [bar]
312 4 6 8 10 12 14
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
Gross IMEP [bar]
HC
[g/k
Wh]
GrossNetBrakeEU VIUS 10
EmissionsObsolete injection system
Not well tuned EGR-λcombination
2 4 6 8 10 12 140
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
Gross IMEP [bar]
NO
x [g
/kW
h]
GrossNetBrakeEU VIUS 10
Outline
• HCCI and fuel efficiency– 50% thermal efficiency
• Partially premixed combustion, PPC– Background
– Why gasoline is the best diesel engine fuel
– 56% thermal efficiency in car size engine
– 57% thermal efficiency in truck size engine
– Why 55% thermal efficiency is better than 57%
– How to reach 26 bar IMEP with US10 NOx, PM, HC and CO engine out
32
3333
Low Compression Ratio PPC
IMEP sweep @ 1300 [rpm]EGR ~ const throughout the sweep, 40-50 [%]λ~ const throughout the sweep, 1.5-1.6 [-]Tin = 308 [K]
Custom piston bowl, rc: 14.3:1
SAE 2010-01-0871
3434
4 6 8 10 12 14 16 1850
55
60
65
70
75
80
85
90
95
100
Gross IMEP [bar]
[%] Combustion Efficiency
Thermal EfficiencyGas Exchange EfficiencyMechanical Efficiency
Efficiencies
3535
4 6 8 10 12 14 16 180
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
Sm
oke
[FS
N]
Gross IMEP [bar]2 4 6 8 10 12 14 16 18
0
0.1
0.2
0.3
0.4
0.5
0.6
Gross IMEP [bar]
NO
x [g
/kW
h]
GrossNetBrakeEU VIUS 10
2 4 6 8 10 12 14 16 180
1
2
3
4
5
6
7
8
9
10
Gross IMEP [bar]
CO
[g/k
Wh]
GrossNetBrakeEU VIUS 10
2 4 6 8 10 12 14 16 180
0.3
0.6
0.9
1.2
1.5
Gross IMEP [bar]
HC
[g/k
Wh]
GrossNetBrakeEU VIUS 10
Emissions
Better tuned EGR-λcombination
36
Emissions – different fuels
2 4 6 8 10 12 14 16 18 200
0.5
1
1.5
2
2.5
Gross IMEP [bar]
Soo
t [F
SN
]
EthanolFR47330CVXFR47331CVXFR47333CVXFR47334CVXFR47335CVXFR47336CVXFR47338CVX
2 4 6 8 10 12 14 16 18 200
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
Gross IMEP [bar]
NO
x [g
/kW
h]
EthanolFR47330CVXFR47331CVXFR47333CVXFR47334CVXFR47335CVXFR47336CVXFR47338CVX
2 4 6 8 10 12 14 16 18 200
2
4
6
8
10
12
Gross IMEP [bar]
CO
[g/k
Wh]
EthanolFR47330CVXFR47331CVXFR47333CVXFR47334CVXFR47335CVXFR47336CVXFR47338CVX
2 4 6 8 10 12 14 16 18 200
1
2
3
4
5
6
7
8
9
10
Gross IMEP [bar]
HC
[g/k
Wh]
EthanolFR47330CVXFR47331CVXFR47333CVXFR47334CVXFR47335CVXFR47336CVXFR47338CVX
Outline
• HCCI and fuel efficiency– 50% thermal efficiency
• Partially premixed combustion, PPC– Background
– Why gasoline is the best diesel engine fuel
– 56% thermal efficiency in car size engine
– 57% thermal efficiency in truck size engine
– Why 55% thermal efficiency is better than 57%
– How to reach 26 bar IMEP with US10 NOx, PM, HC and CO engine out
37
3838
Experimental Apparatus, Scania D13XPI Common RailOrifices 8 [-]
Orifice Diameter 0.19 [mm]
Umbrella Angle 148 [deg]
Engine / Dyno SpecBMEPmax 25 [bar]
Vd 2124 [cm3]
Swirl ratio 2.095 [-]
Standard piston bowl, rc: 17.3:1
3939
5 10 15 20 25 3020
25
30
35
40
45
50
55
60
Gross IMEP [bar]
[%]
η brakeη netη gross
Efficiency
50% brake efficiency seems viable!!!
405 10 15 20 25 3040
50
60
70
80
90
100
Gross IMEP [bar]
[%]
η combustionη gas exchangeη thermalη mechanical
Efficiency
ηηηηη MechanicaleGasExchangmicThermodynaCombustionBrake⋅⋅⋅=
50% brake efficiency maximization of all intermediate efficiencies
RoHR, Cylinder Pressure & Injection Signal
-60 -40 -20 0 20 40 600
50
100
150
200
250
CAD [TDC]
IMEPg: 5 [bar]
lambda: 1.57 [-]EGR: 42.66 [%]CA50: 9.71 [TDC]COV: 2.2 [%]eta comb: 94.16 [%]NOx: 0.108 [g/kWh]HC: 2.7 [g/kW]CO: 23 [g/kW]Soot: 0.0033 [FSN]
Abs Pin: 1.07 [bar]Abs Pex: 1.15 [bar]Tin: 308 [K]Tex: 521 [K]
RoHR/3 [J/CAD]Cylinder Pressure [bar]Injection Current [a.u.]
-60 -40 -20 0 20 40 600
50
100
150
200
250
CAD [TDC]
IMEPg: 26 [bar]
lambda: 1.32 [-]EGR: 47.98 [%]CA50: 13.9 [TDC]COV: 0.56 [%]eta comb: 99.89 [%]NOx: 0.264 [g/kWh]HC: 0.091 [g/kW]CO: 0.31 [g/kW]Soot: 0.26 [FSN]
Abs Pin: 3.64 [bar]Abs Pex: 4.01 [bar]Tin: 293 [K]Tex: 673 [K]
RoHR/3 [J/CAD]Cylinder Pressure [bar]Injection Current [a.u.]
-60 -40 -20 0 20 40 600
50
100
150
200
250
CAD [TDC]
IMEPg: 20 [bar]
lambda: 1.37 [-]EGR: 53.22 [%]CA50: 9.27 [TDC]COV: 0.7 [%]eta comb: 99.89 [%]NOx: 0.201 [g/kWh]HC: 0.082 [g/kW]CO: 0.31 [g/kW]Soot: 0.21 [FSN]
Abs Pin: 3.21 [bar]Abs Pex: 3.48 [bar]Tin: 293 [K]Tex: 606 [K]
RoHR/3 [J/CAD]Cylinder Pressure [bar]Injection Current [a.u.]
-60 -40 -20 0 20 40 600
50
100
150
200
250
CAD [TDC]
IMEPg: 16 [bar]
lambda: 1.36 [-]EGR: 46.69 [%]CA50: 7.6 [TDC]COV: 0.58 [%]eta comb: 99.82 [%]NOx: 0.281 [g/kWh]HC: 0.1 [g/kW]CO: 0.63 [g/kW]Soot: 0.31 [FSN]
Abs Pin: 2.35 [bar]Abs Pex: 2.88 [bar]Tin: 292 [K]Tex: 623 [K]
RoHR/3 [J/CAD]Cylinder Pressure [bar]Injection Current [a.u.]
-60 -40 -20 0 20 40 600
50
100
150
200
250
CAD [TDC]
IMEPg: 11 [bar]
lambda: 1.48 [-]EGR: 46.41 [%]CA50: 6.82 [TDC]COV: 1.2 [%]eta comb: 99.4 [%]NOx: 0.317 [g/kWh]HC: 0.22 [g/kW]CO: 2.6 [g/kW]Soot: 0.05 [FSN]
Abs Pin: 1.76 [bar]Abs Pex: 2.73 [bar]Tin: 291 [K]Tex: 612 [K]
RoHR/3 [J/CAD]Cylinder Pressure [bar]Injection Current [a.u.]
RoHR, Cylinder Pressure & Injection Signal
-60 -40 -20 0 20 40 600
50
100
150
200
250
CAD [TDC]
IMEPg: 5 [bar]
lambda: 1.57 [-]EGR: 42.66 [%]CA50: 9.71 [TDC]COV: 2.2 [%]eta comb: 94.16 [%]NOx: 0.108 [g/kWh]HC: 2.7 [g/kW]CO: 23 [g/kW]Soot: 0.0033 [FSN]
Abs Pin: 1.07 [bar]Abs Pex: 1.15 [bar]Tin: 308 [K]Tex: 521 [K]
RoHR/3 [J/CAD]Cylinder Pressure [bar]Injection Current [a.u.]
RoHR, Cylinder Pressure & Injection Signal
-60 -40 -20 0 20 40 600
50
100
150
200
250
CAD [TDC]
IMEPg: 11 [bar]
lambda: 1.48 [-]EGR: 46.41 [%]CA50: 6.82 [TDC]COV: 1.2 [%]eta comb: 99.4 [%]NOx: 0.317 [g/kWh]HC: 0.22 [g/kW]CO: 2.6 [g/kW]Soot: 0.05 [FSN]
Abs Pin: 1.76 [bar]Abs Pex: 2.73 [bar]Tin: 291 [K]Tex: 612 [K]
RoHR/3 [J/CAD]Cylinder Pressure [bar]Injection Current [a.u.]
RoHR, Cylinder Pressure & Injection Signal
-60 -40 -20 0 20 40 600
50
100
150
200
250
CAD [TDC]
IMEPg: 16 [bar]
lambda: 1.36 [-]EGR: 46.69 [%]CA50: 7.6 [TDC]COV: 0.58 [%]eta comb: 99.82 [%]NOx: 0.281 [g/kWh]HC: 0.1 [g/kW]CO: 0.63 [g/kW]Soot: 0.31 [FSN]
Abs Pin: 2.35 [bar]Abs Pex: 2.88 [bar]Tin: 292 [K]Tex: 623 [K]
RoHR/3 [J/CAD]Cylinder Pressure [bar]Injection Current [a.u.]
RoHR, Cylinder Pressure & Injection Signal
-60 -40 -20 0 20 40 600
50
100
150
200
250
CAD [TDC]
IMEPg: 20 [bar]
lambda: 1.37 [-]EGR: 53.22 [%]CA50: 9.27 [TDC]COV: 0.7 [%]eta comb: 99.89 [%]NOx: 0.201 [g/kWh]HC: 0.082 [g/kW]CO: 0.31 [g/kW]Soot: 0.21 [FSN]
Abs Pin: 3.21 [bar]Abs Pex: 3.48 [bar]Tin: 293 [K]Tex: 606 [K]
RoHR/3 [J/CAD]Cylinder Pressure [bar]Injection Current [a.u.]
RoHR, Cylinder Pressure & Injection Signal
-60 -40 -20 0 20 40 600
50
100
150
200
250
CAD [TDC]
IMEPg: 26 [bar]
lambda: 1.32 [-]EGR: 47.98 [%]CA50: 13.9 [TDC]COV: 0.56 [%]eta comb: 99.89 [%]NOx: 0.264 [g/kWh]HC: 0.091 [g/kW]CO: 0.31 [g/kW]Soot: 0.26 [FSN]
Abs Pin: 3.64 [bar]Abs Pex: 4.01 [bar]Tin: 293 [K]Tex: 673 [K]
RoHR/3 [J/CAD]Cylinder Pressure [bar]Injection Current [a.u.]
47
0 5 10 15 20 25 300
1
2
3
4
5
6
7
8
9
10
Gross IMEP [bar]
Rel
ativ
e M
axim
um P
ress
ure
Ris
e R
ate
[bar
/CA
D]
HD Engine Treshold
0 5 10 15 20 25 300
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
Gross IMEP [bar]C
OV
of I
ME
P [%
] HD Engine Treshold
Combustion Noise & Stability
4848
5 10 15 20 25 300
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
Gross IMEP [bar]
Soo
t [F
SN
]
Emissions
0 5 10 15 20 25 300
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2
Gross IMEP [bar]
Bra
ke H
C [g
/kW
h]
Brake HCUS 10EU VI
0 5 10 15 20 25 300
0.1
0.2
0.3
0.4
0.5
0.6
Gross IMEP [bar]
Bra
ke N
Ox
[g/k
Wh]
Brake NOxUS10EU VI
0 5 10 15 20 25 300
5
10
15
20
25
Gross IMEP [bar]
Bra
ke C
O [g
/kW
h]
Brake COUS 10EU VI
49
Summary
505050
0 5 10 15 20 25 3036
38
40
42
44
46
48
50
52
54
56
58
Gross IMEP [bar]
Bra
ke E
ffici
ency
[%]
D12 High rc, G. 80/75D12 Low rc, G. 69/66D13 Standard, G. 69/66
Brake Efficiency
Brake efficiency in the range of 48-50% seems to be viable between 12.5 and 26 bar gross IMEP.
51
D13 Running on Diesel & Gasoline
5 10 15 20 25 3034
36
38
40
42
44
46
48
50
52
Gross IMEP [bar]
Bra
ke E
ffici
ency
[%]
D13 GasolineD13 Diesel
D13 Diesel was calibrated by Scania and the calibration was done to meet EU V legislation.
Average improvement of 16.6% points @ high load!!!
5252520 5 10 15 20 25 30
0
0.5
1
1.5
2
2.5
3
3.5
4
Gross IMEP [bar]
Bra
ke S
peci
fic H
C [g
/kW
h]
D12 High rcD12 Low rcD13 StandardEU VIUS 10
0 5 10 15 20 25 300
5
10
15
20
25
30
35
Gross IMEP [bar]
Bra
ke S
peci
fic C
O [g
/kW
h]
D12 High rcD12 Low rcD13 StandardEU VIUS 10
0 5 10 15 20 25 300
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
0.55
0.6
Gross IMEP [bar]
Bra
ke S
peci
fic N
Ox
[g/k
Wh]
D12 High rcD12 Low rcD13 StandardEU VIUS 10
0 5 10 15 20 25 300
0.5
1
1.5
2
2.5
3
3.5
4
4.5
Gross IMEP [bar]
Soo
t [F
SN
]
D12 High rcD12 Low rcD13 Standard
Brake Emissions
53
Engine combustion - direction
Spark Ignition (SI) engine (Gasoline,
Otto)
Compression Ignition (CI) engine
(Diesel)
Homogeneous Charge
Compression Ignition (HCCI)
Diesel PPC
+ High Efficiency
+ Ultralow NOx & soot
- Combustion control
- Power density
+ Clean with 3-way Catalyst
- Poor low & part load efficiency
+ High efficiency- Emissions of NOx
and soot
+ Injection controlled- Efficiency at high load
Gasoline PPC
+ High Efficiency+ Low NOx & soot
1900-1995
1995-2005
2005-2010
2010-
The End
Thank you
54
55
Prof. Bengt Johansson
Division of Combustion EnginesDepartment of Energy Sciences
Lund University
SI HCCI PPC
Path to High Efficiency Gasoline Engine
Outline
• Partially premixed combustion, PPC– Summary of
• 56% thermal efficiency in car size engine
• 57% thermal efficiency in truck size engine
• Why 55% thermal efficiency is better than 57%
– Fuel effects in Scania D12 engine
– How to reach 26 bar IMEP with US10 NOx, PM, HC and CO engine out, Scania D13
– Fuel effects in Scania D13 engine
56
575757
RON MON C H/C O/C LHV [MJ/kg] A/F stoichGroup 1 FR47335CVX 99.0 96.9 7.04 2.28 0.00 44.30 15.10
FR47332CVX 97.7 87.5 6.61 2.06 0.07 39.70 13.44
FR47337CVX 96.5 86.1 7.53 1.53 0.00 42.10 14.03
Group 2 FR47338CVX 88.6 79.5 7.21 1.88 0.00 43.50 14.53
FR47330CVX 87.1 80.5 7.20 1.92 0.00 43.50 14.60
FR47331CVX 92.9 84.7 6.90 1.99 0.03 41.60 14.02
Group 3 FR47336CVX 70.3 65.9 7.10 2.08 0.00 43.80 14.83
FR47334CVX 69.4 66.1 7.11 1.98 0.00 43.80 14.68
FR47333CVX 80.0 75.0 7.16 1.97 0.00 43.70 14.65
Group 4 PRF20 20 20 7.2 2.28 0 44.51 15.07
MK1 n.a. 20 16 1.87 0 43.15 14.9
Fuel Matrix
585858
Results
595959
20 30 40 50 60 70 80 90 1000
5
10
15
20
25
RON [-]
IME
P g
ross
[bar
]
Stable operational load vs. fuel type
Tested Load Area
60606030 35 40 45 50 55 60 65 70
1000
1200
1400
1600
1800
2000
2200
2400Adiabatic Flame Temperature
EGR Ratio [%]
Tem
pera
ture
[K]
λ=1λ=1.1λ=1.2λ=1.3λ=1.4λ=1.5λ=1.6λ=1.7λ=1.8λ=2λ=2.5λ=3λ=3.5λ=4
HC/COF/A
EQ
UIV
ALE
NC
E R
ATIO
TEMPERATURE
NOx - ηcomb Trade – Off Solution
It is possible to achieve low NOx and still keep high combustion efficiency in the whole load range!
0 0.2 0.4 0.6 0.8 190
91
92
93
94
95
96
97
98
99
100
NOx [g/kWh]
Com
bust
ion
Effi
cien
cy [%
] G. ON 99/97G. ON 98/88G. ON 97/86G. ON 93/85G. ON 89/80G. ON 87/81G. ON 80/75G. ON 70/66G. ON 69/66PRF20
616161
In certain operating range, some fuels are capable to comply EU VI & US10 legislations and still keep high
efficiency without compromising the efficiency!
Efficiency & Emissions
0 0.2 0.4 0.6 0.8 150
51
52
53
54
55
56
57
58
59
60
NOx [g/kWh]
Gro
ss In
dica
ted
Effi
cien
cy [%
]
G. ON 99/97G. ON 98/88G. ON 97/86G. ON 93/85G. ON 89/80G. ON 87/81G. ON 80/75G. ON 70/66G. ON 69/66PRF20
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
0.045
0.05
Indicated NOx [g/kWh]
Soo
t [g/
kWh]
G. ON 99/97G. ON 98/88G. ON 97/86G. ON 93/85G. ON 89/80G. ON 87/81G. ON 80/75G. ON 70/66G. ON 69/66D. CN 52PRF20EU VIUS10
626262
Soot Emissions
0 5 10 15 20 25 300
0.5
1
1.5
2
2.5
3
Gross IMEP [bar]
Soo
t [F
SN
]G. ON 99/97G. ON 98/88G. ON 97/86G. ON 93/85G. ON 89/80G. ON 87/81G. ON 80/75G. ON 70/66G. ON 69/66D. CN 52PRF20
Diesel vs. Gasoline
636363
Low soot even @ λ 1.3 higher power density without producing smoke!
Higher Power Density
1 1.1 1.2 1.3 1.4 1.50
0.5
1
1.5
2
2.5
3
λ [-]
Soo
t [F
SN
]
IMEPg: 20 & 25 [bar]
G. ON 99/97G. ON 98/88G. ON 97/86G. ON 93/85G. ON 89/80G. ON 87/81G. ON 80/75G. ON 70/66G. ON 69/66D. CN 52PRF20
646464
Acoustic Noise
1 1.5 2 2.5 3 3.5 41
1.5
2
2.5
3
3.5
4
4.5
5
abs Inlet Pressure [bar]
Max
Pre
ssur
e R
ise
Rat
e [b
ar/C
AD
]
Motored Engine
MeasuredNormalized
0 5 10 15 20 25 301
3
5
7
9
11
13
15
Gross IMEP [bar]
Rel
ativ
e M
ax P
ress
ure
Ris
e R
ate
[bar
/CA
D]
G. ON 99/97G. ON 98/88G. ON 97/86G. ON 93/85G. ON 89/80G. ON 87/81G. ON 80/75G. ON 70/66G. ON 69/66D. CN 52PRF20Treshold
656565
Idle
666666
Efficiencies & Emissions
3 4 5 6 7 8 9 1030
32
34
36
38
40
42
44
46
48
50
Combustion Phasing [TDC]
[%]
3 4 5 6 7 8 9 1090
91
92
93
94
95
96
97
98
99
100
[%]
G. ON 69/66
Combustion Efficiency
Gross Indicated Efficiency [%]Thermal Efficiency [%]
3 4 5 6 7 8 9 100
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
Combustion Phasing [TDC]
NO
x / S
oot [
g/kW
h]
G. ON 69/66
3 4 5 6 7 8 9 100
5
10
15
20
25
30
35
40
45
50
CO
/ H
C [g
/kW
h]
NOxSoot
COHC
67
Viability of Low ON Gasolines for PPC?
686868Octane Number of the gasoline streams span from 99 to 50 RON Gasolines with 70 RON are already produced!!!
Oil Refineries Production Layout
90 < ON < 9950 < ON < 75
50%
20%
30%
696969
Oil Refineries Perspectives
Oil refineries are a very stiff system and their kerosene, diesel and gasoline production can not be easily varied without major investments we need to build highly efficient vehicles with the available fuels…
707070Page 70
20 30 40 50 60 70 80 90 1000
5
10
15
20
25
RON [-]
IME
P g
ross
[bar
]High ON Gasolines in Scania D13
What to do with these fuels?!
Still to be used in SI engines?!
Minimum Turbo Efficiency
71
Ideal burn rate?Conditions:
1. CA50: 8 [ATDC].
2. CA90-10: 15 [CAD].
3. Engine geometry: custom Scania D13.
4. Inlet temperature: 303 [K].
5. Reference temperature: 298 [K].
6. Engine speed: 1250 [rpm].
7. Differential pressure exhaust minus inlet: 0.25 [bar].
8. Cylinder wall temperature: 450 [K].
9. Heat transferred modeled with the Woschni equation and tuned to match the experimental results
10. The rate of heat release has been approximated with a Wiebe function.
11. EGR is added in order to have 1.35 as λ. If the inlet pressure was not enough to
have λ without EGR higher than 1.35, EGR was set to zero.
12. The combustion efficiency was assumed to be 100%.
13. Lower heating value 43.8 MJ/kg, stoichiometric air fuel ratio 14.68.
72
Exhaust Loss
73
Heat transfer loss
74
The rest (useful work)
75
Boosting reduce heat losses
76
A-B-C of Fuel Consumption
A. Car size
B. Engine size
C. Engine efficiency in right operating conditions
77
Porsche 911 performance with 100+ mpg?
78
• Two persons
• 100 liter of storage capacity
Porsche 911 data
79
M=1550 kgCr=0.012Av=1.96 m2Cd=0.33
Vd=3.8 literP=355 PS (hp)T=400 Nm
Performance 0-60: 4.6 sV,max=300 km/h ( 186.5 mph)Fuel consump.= 12.0 l/100 km (19.6 mpg)
Power needed @300 km/h (186.5 mph)
80
( )
hpkW
xxxxxxx
vvACmgCP vDaR
1.3268.239
6.3300
6.330096.133.02.15.081.91550012.0
5.02
2
==
+
=+= ρ
The ”Cigar”
Two person capacity is often enough
82
UK National Office of Statistics:“The average car occupancy is 1.6 people per car and for commuting it's 1.2 “
A carpool in California is a car with ONE person if the car is fuelefficient…
The ”Cigar”
http://www.peraves.ch/
Existing large model use large BMW 1200 cc MC engine. With turbo a top speed of 315 km/h and fuel consumption of 3.5 l/100 km (67 mpg)
Power needed @300 km/h (186.5 mph)
84
( )
hpkW
xxxxxxx
vvACmgCP vDaR
7.492.37
6.3300
6.33000.110.02.15.081.9250012.0
5.02
2
==
+
=+= ρ
Cigar design specificationsCd=0.1Av=0.5-1 m2
m= 250 kgCr=0.012 (two wheels)
Power needed at 50 and 100 km/h (31- 62 mph)
Porsche 911 vs. cigar
85
Speed (km/h) 911 Cigar Unit Ratio50 3.57 0.57 kW 6.28100 13.4 2.1 kW 6.36300 239.8 37.2 kW 6.45
50 4.86 0.77 hp 6.28100 18.2 2.9 hp 6.36300 326.1 49.7 hp 6.45
Acceleration proportional to power/mass ratio:Cigar: 250/49.7=5.03 kg/hp911: 1550/355=4.37 kg/hp
A. Car size • With more correct car size the engine size can
be reduced a factor of 6 i.e. single cylinder version of 911 engine with 633 cc displacement is enough
• Porsche 911 has a fuel consumption of 12 l/100 km (19.6 mpg)
• Cigar would have 12/6=2 l/100 km (117.6 mpg) without any need of new engine technology. (Scaling both engine and car size)
86
0 20 40 60 80 100 120 140 160 180 200 220Bilhast. [km/h]
B. Engine size• A Porsche 911 does not operate at optimum
load points in normal driving.
• At 50 km/h the estimated load is only 2 bar BMEP or less
• Bsfc=400 g/kWh
(ηb=21 %)
87
Engine downsizingThree options
1. Turbo or supercharge a small engine
2. Cylinder deactivation of large engine
3. Variable displacement i.e. variable engine size
88
B.1. Mercedes CDI 250, 2.1 liter
89
Vd=2143 ccTorque= 500 Nm (369 lb-ft)
90
Two stage turbo
Engine downsizing- MB 250 CDI
91
Displacement of 2.1 liter giving 224 hp and 500 Nm of torque : 30 bar BMEP is now full load NOT 10 or 20 barFuel consumption;C-class 5.1 l/100 km (46.1 mpg), E-class 5.3 l/100 km (44.4 mpg),S-class 5.9 l/100 km (39.9 mpg)
CO2:C-class 139 g/kmE-class 143 g/kmS-class 155 g/km
B2: Dual engine concept
• Use one small and one large engine
• As an example:– One 2 cylinder 1 liter engine
– One 4 cylinder 2 liter engine
• This gives us 1, 2 or 3 liter to choose from
92
Layout 4 +2 cyl
FAS
Transm.
93
Fiat 2-cylinder production engine
Operation• 2-cyl at low loads• 4-cyl operation at higher load operation
(Autobahn)• 6-cyl operation at highest loads• 6-cyl + FAS at transients
(with FAS start of 4-cyl)• FAS for regenerative braking• FAS for lowest speed operation ( < 5 km/h)• Manual selection should be possible
94
B3: Variable displacement engine
• If we can change displacement, Vd, engine load, P, can be controlled without reducing BMEP!
95
td n
NVbmepP =
Atkinson Cycle
96
Displacement from 0.15 to 0.85 l per cylinder gives 0.6 to 3.4 l four cylinder engine at full load (@max BMEP)
Atkinson engine with variable displacement
97
Atkinson engine efficiency
98
Atkinson engine thermal efficiency
99
A-B-C of Fuel Consumption
A. Car size
B. Engine size
C. Engine efficiency in right operating conditions(Maximum engine efficiency)
100
Summary /ABC of fuel consumption
A. Correct car size gives factor of 6 in fuel consumption
B. Correct load point gives factor 2 in fuel consumption (21%-42% or 400-200 g/kWh)
C. Partially Premixed Combustion have the potential to extend brake efficiency to 50% with US10/Euro emissions. With further optimization 55% could be reached
D. With waste heat recovery 60% should be possible giving a factor of 3 from today.
A total reduction potential of factor 18!
101
Cars and traffic situation
102