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Real-time evaluation of detailed chemistry based on SRM-GT-Power
coupling for HCCI engine application
S. Mosbach, A. Aldawood, M.Celnik, A. Bhave and M. Kraft
11th GT-SUITE ConferenceBirmingham, MI, 13/11/2007
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Content
• SRM approach
• Model capabilities
• Transient simulation with detailed kinetics
http://como.cheng.cam.ac.uk
Acknowledgements
• Hongzhi Zhang, University of Utah
• Members of the CoMo Group, Cambridge
• GT-SUITE support team
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Models PFI, and multiple DI
Fuels modelled: conventional and alternative surrogates
Detailed chemical kinetics
Accounts for inhomogeneities in composition and temperature, and
fluctuations
Efficient operation on standard desktop PCs
Integrates seamlessly with1-D engine cycle code (full engine
cycle simulation)
chemical kinetics code
Detailed model description
• SAE 2004-01-0561, 2005-01-0161, 2006-01-1362, 2007-01-1880
• Int. J. Engine Res., 5, 1, 2004, 93-104
• Combust. Flame: [144, 2006, 634-637], [147, 2006, 118-132]
SRM: Stochastic Reactor Model
SRM benefits
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f (T,t)
Nf (T,t)
• Fuel injection• Turbulent mixing• Convective heat loss•
Chemical kinetics
Stochastic particle system
Turbulent reactive flow
PDF transport equation
Stochastic approach
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Temporal evolution (T-Φ space)
• Injection at -40 CAD ATDC
• Injection duration: 3 CAD
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1. Multiple direct injection
2. Boundaries of HCCI operation
3. Soot PSDF in SRM
4. Transient simulation with detailed kinetics
SRM capabilities
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JSAE 20077195
1. Optimal second injection in PCCI
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800
1000
1200
1400
1600
1800
-40 -30 -20 -10 0 10 20 30 40
cycle 55cycle 56cycle 57cycle 58cycle 59cycle 60cycle 61cycle
62cycle 63cycle 64cycle 65
T (K
)
CAD
Partial Burn
KnockMisfire
Indicated thermal efficiency (%)
• Knock: > 10 bar/CAD
• Partial burnExtremely high CO and HCVery low IMEP
• MisfireCyclic variation
SAE Paper 2005-01-0161
800
1000
1200
1400
1600
1800
2000
-40 -30 -20 -10 0 10 20 30 40
cycle 55cycle 56cycle 57cycle 58cycle 59cycle 60cycle 61
T (K
)
CAD
2. Boundaries of HCCI
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• Prediction of soot aggregates
3. Soot PSDF coupled with SRM
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Temporal evolution of PSDF
Injection timing: -10 CAD ATDC
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Soot characteristics
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• Problem: Computational expense (1-2 hrs per cycle)
• Solution: Storage/retrieval
• Studies of transient engine operation, control, DOE, and
optimization involve simulations over many cycles
• Incorporate tabulation as external cylinder model into
GT-Power
4. Real-time transient simulation
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• Full-cycle simulations through coupling to GT-Power 6.2 as
external cylinder model
• Collaboration with M. Sjöberg and J. Dec
Real-time transient simulation
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GT-Power engine map with sensors and controller
Example: transient control
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• PID controller changes fuel composition (octane number) such
that…
• Imposed equivalence ratio profile
• … ignition timing (CA50) is held at a given set point.
Example: transient control (II)
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• and emissions (e.g.)
• Since SRM accounts for inhomogeneities, turbulent mixing, and
detailed chemical kinetics, can look at…
• maximum pressure rise rates,
Misfire cycle
Example: transient control (III)
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• Live GT-Power simulation…
Example: transient control (IV)
Real-time evaluation of detailed chemistry based on
�SRM-GT-Power coupling for HCCI engine applicationTemporal
evolution of PSDF
