ICEF2005-1240
Alternative Modes Combustion Study: HCCI Fueled With Heptane and Spark Ignition Fueled with Reformer Gas A Study of a Dual-Mode Combustion, Dual-Fuel Engine
Vahid Hosseini, M David Checkel Mechanical Engineering Department University of Alberta, Canada
Outline
Introduction
HCCI
Combustion
Hydrogen-Fueled Spark Ignition (SI) Engine
Reformer Gas (RG)
HCLB-SI/HCCI Concept
Experimental Setup
Engine
and DAQ System
Fuels
Results
Heptane-Fueled
HCCI
RG-Enriched HCCI
RG-Fueled SI
Conclusion
Outline
Introduction
HCCI Combustion
Hydrogen-Fueled SI engine
Reformer Gas
HCLB-SI/HCCI Concept
Experimental Setup
Engine
and DAQ System
Fuels
Results
Heptane-Fueled
HCCI
RG-Enriched HCCI
RG-Fueled SI
Conclusion
HCCI: Homogenous Charge Compression Ignition
Spontaneous Multi-Site Combustion of an Air/Fuel Mixture
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HCCI: Homogenous Charge Compression Ignition
Spontaneous Multi-Site Combustion of an Air/Fuel Mixture
GOOD Low NOx
High Efficiency
No Throttle at Part-Load
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HCCI: Homogenous Charge Compression Ignition
Spontaneous Multi-Site Combustion of an Air/Fuel Mixture
GOOD Low NOx
High Efficiency
No Throttle at Part-Load
ICEF2005-1240
BAD High HC, CO
Limited Operating Range
Impossible Cold-start, Full-load
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HCCI: Homogenous Charge Compression Ignition
Spontaneous Multi-Site Combustion of an Air/Fuel Mixture
GOOD Low NOx
High Efficiency
No Throttle at Part-Load
High HC, CO
Limited Operating Range
Impossible Cold-start, Full-load
UGLY
Difficult
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BAD
to Control Combustion Timing
1
HCCI / SI Engine Comparison:
Higher Peak Pressure, Higher Rate of Heat Release, Shorter Combustion Duration SI, CNG, λ=1, EGR = 0 % HCCI, Heptane,
HCCI, n-Heptane, λ = 2.81, EGR = 0 %
60
λ=2.81, EGR = 0 %
SI, CNG,
λ = 1.00,
EGR= 0 %
50
800
8.35 bar
Pressure (bar)
Total Net Heat Release (J)
1000
600
400
200
40
30
20
10
0
BD 0
-200 -120
-80
-40
0
CAD, aTDC
40
80
-40
0
80
CAD, aTDC
CAD= Crank Angle Degree
aTDC= after Top Dead Center ICEF2005-1240
40
2
Limited Operating Region
3
Low IMEP Boundary
2.5
λ
λ= Relative Air/Fuel Ratio
3.5
Knock Boundary 2
1.5
Misfire 1 0
10
20 30 EGR(%)
40
50
EGR= Exhaust Gas Recirculation ICEF2005-1240
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An Existing Solution to HCCI Disadvantages
A Dual Mode Engine:
/
Spark Ignition High Octane Number Fuel Low Compression Ratio Low Dilution Level
HCCI Low Octane Number Fuel High Compression Ratio High Dilution Level
Transient Condition
Variable Valve Timing
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Motivation for This Study
HCCI is spontaneous and sensitive to fuel properties ; hence:
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Motivation for This Study
HCCI is spontaneous and sensitive to fuel properties ; hence: Question: Is it possible to run a dual-mode SI/HCCI engine without altering geometry and by altering fuel properties ?
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An Existing Solution to HCCI Disadvantages
A Dual Mode Engine:
/
Spark Ignition High Octane Number Fuel Low Compression Ratio Low Dilution Level
HCCI Low Octane Number Fuel High Compression Ratio High Dilution Level
Variable Valve Timing
ICEF2005-1240
A New Solution to HCCI Disadvantages
A Dual Mode Engine:
/
Spark Ignition High Octane Number Fuel Low Compression Ratio Low Dilution Level
HCCI Low Octane Number Fuel High Compression Ratio High Dilution Level
HCLB-SI/HCCI (High Compression ratio Lean Burn-SI/HCCI) ICEF2005-1240
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Outline
Introduction
HCCI
Combustion
Hydrogen-Fueled
SI engine
Reformer
Gas
HCLB-SI/HCCI Concept
Experimental Setup
Engine
and DAQ System
Fuels
Results
Heptane-Fueled
HCCI
RG-Enriched HCCI
RG-Fueled SI
Conclusion
Previous Studies:
Hydrogen as a fuel for SI engine:
Ultra-low
lean limit, high efficiency , no carbon emissions, less cyclic variation, and higher octane number
Hydrogen as an additive for dual-fuel SI engine:
Cold-start
enhancement, Combustion enhancement in adverse condition
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Outline
Introduction
HCCI
Combustion
Hydrogen-Fueled SI engine
Reformer
Gas
HCLB-SI/HCCI
Concept
Experimental Setup
Engine
and DAQ System
Fuels
Results
Heptane-Fueled
HCCI
RG-Enriched HCCI
RG-Fueled SI
Conclusion
Reformer Gas
Hydrogen can be stored in a vehicle as:
Compressed
gas
Cryogenic liquid
Liquid dissolved in metal hydride
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Reformer Gas
Hydrogen can be stored in a vehicle as:
Compressed
gas
Cryogenic liquid
Liquid dissolved in metal hydride OR
It can be produced on-board:
Thermal
decomposition
Steam reforming
Partial oxidation ICEF2005-1240
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Reformer Gas
Hydrogen can be stored in a vehicle as:
Compressed
gas
Cryogenic liquid
Liquid dissolved in metal hydride OR
It can be produced on-board:
Thermal
decomposition
Steam reforming
Partial oxidation ICEF2005-1240
Produces solid carbon Stationary and Industrial Applications Mobile Applications
8
Outline
Introduction
HCCI
Combustion
Hydrogen-Fueled SI engine
Reformer Gas
HCLB-SI/HCCI
Concept
Experimental Setup
Engine
and DAQ System
Fuels
Results
Heptane-Fueled
HCCI
RG-Enriched HCCI
RG-Fueled SI
Conclusion
How does the HCLB–SI/HCCI Work? SI Compression Ratio
Fuel Control Method Load
ICEF2005-1240
HCCI
Constant, Relatively High SI RG
Diesel Type
Spark
Mixture Quality RG Enrichment
Startup, Idle, High Load
Part Load
9
Outline
Introduction
HCCI
Combustion
Hydrogen-Fueled SI engine
Reformer Gas
HCLB-SI/HCCI Concept
Experimental Setup
Engine
and DAQ System
Fuels
Results
Heptane-Fueled
HCCI
RG-Enriched HCCI
RG-Fueled SI
Conclusion
Experimental Setup
Waukesha CFR Engine
CR=11.5
Constant
Speed =800 RPM
Manual Control EGR
Intake heater
Labview DAQ System
High speed pressure measurement with 0.1 CAD resolution
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Outline
Introduction
HCCI
Combustion
Hydrogen-Fueled SI engine
Reformer Gas
HCLB-SI/HCCI Concept
Experimental Setup
Engine
and DAQ System
Fuels
Results
Heptane-Fueled
HCCI
RG-Enriched HCCI
RG-Fueled SI
Conclusion
Fuel Properties
A mixture of 25% CO and 75% H2 was used as simulated RG n-Heptane was used as the low octane fuel
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Fuel Properties
A mixture of 25% CO and 75% H2 was used as simulated RG n-Heptane was used as the low octane fuel Heptane
RG
Formula
C7H16
0.25 CO+0.75 H2
Octane
0
140 (H2), 106(CO)*
Molar Mass (kg/kmol)
100.203
8.514
LHV(KJ/Kg)
44,926
29,471
70**
210 (H2), 28(CO)
Laminar Burning Velocity (cm/s)***
* SAE Paper, 2004-01-0975 ** SAE Paper, 800103, P=6 atm, T=520 K ICEF2005-1240
*** P=1 atm, T=298 K, φ=1
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Outline
Introduction
HCCI
Combustion
Hydrogen-Fueled SI engine
Reformer Gas
HCLB-SI/HCCI Concept Experimental Setup
Engine and DAQ System
Fuels
Results
Heptane-Fueled
RG-Enriched
HCCI
RG-Fueled SI
Conclusion
HCCI
Operating Region 3.5
3
Low IMEP Boundary
λ
2.5
Knock Boundary 2
1.5
Misfire 1 0
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10
20 30 EGR(%)
40
50
12
Combustion Control by Combination of λ and EGR: Accumulated Net Heat Release (J)
Effect on Combustion Timing 1000
90% ANHR
800
600
400
SOC
200
10% ANHR
0
Combustion Duration
-200 -120
-80
-40
0
40
80
CAD, aTDC
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Combustion Control by Combination of λ and EGR:
Effect on Combustion Timing 45% EGR 35% EGR 0% EGR
cr ea s
es
16
R
In
14
EG
Start of Combustion (bTDC)
Retarded Combustion
18
12
10
8 1
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1.5
2
λ
2.5
3
3.5
14
Combustion Control by Combination of λ and EGR:
Effect on Combustion Duration Combustion Duration (CAD)
Shorter Combustion
32
28
20% EGR 25% EGR 35% EGR 40% EGR 45% EGR
24
20
16
12 1.2
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1.6
λ
2
2.4
2.8
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Outline
Introduction
HCCI
Combustion
Hydrogen-Fueled SI engine
Reformer Gas
HCLB-SI/HCCI Concept Experimental Setup
Engine and DAQ System
Fuels
Results
Heptane-Fueled
HCCI
RG-Enriched
RG-Fueled
Conclusion
SI
HCCI
Effect of RG on Heptane-Fueled HCCI Combustion: Start of Combustion (CAD,aTDC)
Retarded Combustion 2
0
-2
-4
-6 0
10
20
30
Reformer Gas Mass(%) ICEF2005-1240
40
16
Effect of RG on Heptane-Fueled HCCI Combustion:
Faster Combustion Combustion Duration (CAD)
14
12
10
8
6
0
20
40
60
80
Reformer Gas Mass (%) ICEF2005-1240
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Effect of RG on Heptane-Fueled HCCI Combustion:
Higher Power 4.4
IMEP(bar)
4
3.6
3.2
2.8 0
20
40
60
80
Reformer Gas Mass Fraction(%) ICEF2005-1240
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Effect of RG on Heptane-Fueled HCCI Combustion:
Higher Exhaust Temperature
Exhaust Temp(oC)
340
320
300
280
260
240
220 0
20
40
60
80
Reformer Gas Mass Fraction(%) ICEF2005-1240
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Effect of RG on Heptane-Fueled HCCI Combustion: Indicated Specific NOx (gr/kW-hr)
Higher NOx 5
0.1 0.08 0.06
4
0.04 0.02 0
3
0
0.5
1
2
1
0 0
20
40
60
80
Reformer Gas Mass Fraction(%) ICEF2005-1240
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Effect of RG on Heptane-Fueled HCCI Combustion:
Indicated Specific HC (gr/kW-hr)
Lower HC 16
12
8
4
0 0
20
40
60
80
Reformer Gas Mass Fraction(%) ICEF2005-1240
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Outline
Introduction
HCCI
Combustion
Hydrogen-Fueled SI engine
Reformer Gas
HCLB-SI/HCCI Concept Experimental Setup
Engine and DAQ System
Fuels
Results
Heptane-Fueled
RG-Enriched
HCCI
RG-Fueled
Conclusion
HCCI
SI
HCLB-SI/HCCI Comparison with CNG-Fueled SI
Power
8
Efficiency SI, CNG SI, Reformer Gas HCCI, n-Heptane
IMEP (bar)
7 36.68 37.1 6 35.53 43.52
5
44.15
4
43.72 43.71
3 1 ICEF2005-1240
1.5
2
λ
2.5
3
3.5
23
HCLB-SI/HCCI Comparison with CNG-Fueled SI Accumulated Net Heat Release (J)
Heat Release SI,CNG SI,Reformer Gas HCCI, n-Heptane HCCI, n-Heptane+15% Reformer Gas
1200
800
400
0 -40
-20
0
20
40
CAD (aTDC) ICEF2005-1240
60
80
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HCLB-SI/HCCI Comparison with CNG-Fueled SI Indicated Specific NOx (gr/kW-hr)
NOx 12
n-Heptane, HCCI HCCI, n-Heptane/RG SI, CNG SI, RG
8
4
0 0.8
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1.2
1.6
λ
2
2.4
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HCLB-SI/HCCI Indicated Specific NOX (gr/kW-hr)
NOx-IMEP Map n-Heptane, HCCI HCCI, n-Heptane/RG SI, RG
5
4
3
2
1
0 2.8
3.2
3.6
4
IMEP (bar) ICEF2005-1240
4.4
4.8
26
HCLB-SI/HCCI Indicated Specific NOX (gr/kW-hr)
NOx-IMEP Map n-Heptane, HCCI HCCI, n-Heptane/RG SI, RG
5
4
3
2
1
0 2.8
3.2
3.6
4
IMEP (bar) ICEF2005-1240
4.4
4.8
26
HCLB-SI/HCCI Indicated Specific NOX (gr/kW-hr)
NOx-IMEP Map n-Heptane, HCCI HCCI, n-Heptane/RG SI, RG
5
4
3
2
1
HCCI 0 2.8
3.2
3.6
4
IMEP (bar) ICEF2005-1240
4.4
4.8
26
HCLB-SI/HCCI Indicated Specific NOX (gr/kW-hr)
NOx-IMEP Map n-Heptane, HCCI HCCI, n-Heptane/RG SI, RG
5
4
3
2
RG-Enriched HCCI 1
0 2.8
3.2
3.6
4
IMEP (bar) ICEF2005-1240
4.4
4.8
26
HCLB-SI/HCCI Indicated Specific NOX (gr/kW-hr)
NOx-IMEP Map n-Heptane, HCCI HCCI, n-Heptane/RG SI, RG
5
4
3
2
1
RG-Fueled SI
0 2.8
3.2
3.6
4
IMEP (bar) ICEF2005-1240
4.4
4.8
26
Heptane-Fueled HCCI Combustion Variability
Heptane HCCI
IMEP=4.91 bar COVimep=1.04%
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RG-Fueled SI Combustion Variability
RG, SI
IMEP = 5.03 bar COVimep=3.06 %
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CNG-Fueled HCCI Combustion Variability
CNG, SI
IMEP= 7.33 bar COVimep=9.89 %
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Combustion Variability Comparison HCCI, Heptane
SI, RG
SI, CNG
IMEP (bar)
4.91
5.03
7.33
COVimep(%)
1.04
3.06
9.89
IMEP=4.91 bar COVimep=1.04%
ICEF2005-1240
IMEP = 5.03 bar COVimep=3.06 %
IMEP= 7.33 bar COVimep=9.89 %
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Outline
Introduction
HCCI
Combustion
Hydrogen-Fueled SI engine
Reformer Gas
HCLB-SI/HCCI Concept Experimental Setup
Engine and DAQ System
Fuels
Results
Heptane-Fueled
RG-Enriched
HCCI
HCCI
RG-Fueled SI
Conclusion
Conclusions
Avoiding cost and complexity of VVT it is possible to run an engine with the concept of HCLB-SI/HCCI in startup, full load and part load without throttling. RG fueled SI engine produces less power and less cyclic variation but more EGR tolerability than CNG fueled same SI engine.
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Conclusions
HCCI combustion of a diesel type fuel can be controlled by dilution effects and by adding RG at different operating conditions. The combination of regulating EGR, regulating λ and/or addition of RG has the potential to provide fast response control mechanisms for HCCI combustion.
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Conclusions
The effect on combustion characteristics of RG addition with different base fuels and also the effect of different RG compositions requires further study.
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Acknowledgment
The authors gratefully acknowledge the contribution of the Auto21 National Center of Excellence to supporting this work.
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Thank you for your Attention
Questions ?
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Effect of RG on Minimum λ 1.5
λ
1.4
1.3
1.2
1.1 20
30
40
50
60
70
Reformer Gas Mass (%)
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