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Simulations of Fuel/Air Mixing, Combustion, and Pollutant Formation in a Direct Injection Gasoline Engine
Technical Paper
2002-01-0835
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
Simulations of a Direct Injection Spark Ignition (DISI) engine have been performed for both early injection with homogeneous charge combustion and for late injection with stratified charge combustion. The purpose has been to study flow characteristics, fuel/air mixing, combustion, and NOx and soot formation. Focus is put on the combustion modeling.
Two different full load cases with early injection are simulated, 2000 rpm and 6000 rpm. One load point with late injection is simulated, 2000 rpm and 2.8 bar net MEP. Three different injection timings are simulated at the low load point: 77, 82, and 87 CAD bTDC.
The spray simulations are tuned to match measured spray penetrations and droplet size distributions at both atmospheric and elevated pressure. Boundary conditions for the engine simulations are taken from 1-D gas exchange simulations that are tuned to match engine tests. The engine simulations start 380 CAD's before TDC and include the closing of the exhaust valves, the whole intake stroke, injection, combustion, and expansion to 113 CAD aTDC. Combustion is simulated using a turbulent Flame Speed Closure (FSC) model. The model takes into account the effects of local mixture composition, turbulence, temperature, and pressure and predicts reasonably well the heat release rate in all the cases without tuning of any constants. From this it is concluded that it is well suited for SI engine combustion predictions. The model also handles the diffusion controlled post oxidation of the unburned fuel from overly rich regions.
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Wallesten, J., Lipatnikov, A., and Chomiak, J., "Simulations of Fuel/Air Mixing, Combustion, and Pollutant Formation in a Direct Injection Gasoline Engine," SAE Technical Paper 2002-01-0835, 2002, https://doi.org/10.4271/2002-01-0835.Also In
References
- Fan L. and Reitz R.D., “Spray and Combustion Modeling in Gasoline Direct-Injection Engines”, Atomization and Sprays, vol 10, pp. 219-249, 2000.
- Abraham J., Bracco F.V. and Reitz R.D., “Comparisons of Computed and Measured Premixed Charge Engine Combustion”, Combustion and Flame, vol. 60, pp.309-322, 1985.
- Ranasinghe J. and Cant S., “A Turbulent Combustion Model for a Stratified Charged, Spark Ignited Internal Combustion Engine”, SAE Paper 2000-01-0275, 2000.
- Baritaud T.A., Duclos J.M., and Fusco A., “Modeling Turbulent Combustion and Pollutant Formation in Stratified Charge SI Engines”, Twenty-Sixth Symposium (Internationsl) on Combustion, pp 2627-2635, 1996.
- Lipatnikov, A.N. and Chomiak, J., “Turbulent Flame Speed and Thickness: Phenomenology, evaluation, and application in multi-dimensional simulations”, Progress in Energy and Combustion Science, 28, pp.1-73, 2002.
- Zimont, V.L., “To Computations of Turbulent Combustion of Partially Premixed Gases”, Chemical Physics of Combustion and Explosion Processes. Combustion of Multi-phase and Gas Systems, OIKhF, Chernogolovka, pp.77-80, 1977 (in Russian).
- Zimont, V.L., Combustion, Explosions, and Shock Waves, 15:305, 1997.
- Lipatnikov, A.N. and Chomiak, J., “A Simple Model of Unsteady Turbulent Flame Propagation”, SAE Paper No. 972993, 1997.
- Wallesten J, Lipanikov A.N. and Nisbet J., “Turbulent Flame Speed Closure Model: Further Development and Implementation for 3-D Simulation of Combustion in SI Engine”, SAE Paper 982613, 1998.
- Lipatnikov. A., Wallesten, J., and Nisbet, J., “Testing of a Model for Multi-Dimensional Computations of Turbulent Combustion in Spark Ignition Engines”, The Fourth International Symposium COMODIA 98, 1998.
- FIRE Manual, Version 7.2b, AVL LIST GmbH, Graz, 2000.
- Hörnquist N., “Spraymodellering i CFD-koden FIRETM”, Diploma work, Dept. of Construction and Production Technology, University of Linköping, Linköping, 1999.
- Naber, J.D. and Reitz, R.D., “Modeling Engine Spray/Wall Impingement”, SAE 880107, 1988.
- Wallesten, J. and Golovitchev. V., “Calculations of Laminar Flame Speeds for Iso-octane Mixtures Including Effects of Pressure, Temperature, and Exhaust Gas Dilution”, To be published.
- Gülder, Ö.L., “Laminar Burning Velocities of Methanol, Ethanol and Isooctane-Air Mixtures”, Nineteenth Symposium (International) on Combustion/The Combustion Institute, 1982, pp. 275-281
- Metghalchi, M. and Keck, J.C., “Burning Velocities of Mixtures of Air With Methanol, Iso-octane, and Indolene at High Pressure and Temperature”, Combustion and Flame 48, pp. 191-210, 1982.
- Müller, U.C., Bollig, M., and Peters, N., “Approximations for Burning Velocities and Markstein Numbers for Lean Hydrocarbon and Methanol Flames”, Combustion and Flame 108: 349-356 (1997)
- Davis, S.G., Law, C.K., “Determination of and Fuel Structure Effects on Laminar Flame Speeds of C1 to C8 Hydrocarbons”, Combust. Sci. and Tech., 1998, Vol. 140, pp. 427-449
- Bradley, D., Hicks, R.A., Lawes, M., Sheppard, C.G.W., Wooley, R., “The Measurement of Laminar Burning Velocities and Markstein Numbers for Iso-octane and Iso-octane-n-Heptane-Air Mixtures at Elevated Temperatures and Pressures in an Explosion Bomb”, Combustion and Flame 115: 126-144 (1998)
- Ra, Y. and Cheng, W.K., “Laminar Flame Propagation Through a Step-Stratified Charge”, COMODIA, 2001.