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Thermodynamic and Chemical Effects of EGR and Its Constituents on HCCI Autoignition
ISSN: 0148-7191, e-ISSN: 2688-3627
Published April 16, 2007 by SAE International in United States
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EGR can be used beneficially to control combustion phasing in HCCI engines. To better understand the function of EGR, this study experimentally investigates the thermodynamic and chemical effects of real EGR, simulated EGR, dry EGR, and individual EGR constituents (N2, CO2, and H2O) on the autoignition processes. This was done for gasoline and various PRF blends. The data show that addition of real EGR retards the autoignition timing for all fuels. However, the amount of retard is dependent on the specific fuel type. This can be explained by identifying and quantifying the various underlying mechanisms, which are: 1) Thermodynamic cooling effect due to increased specific-heat capacity, 2) [O2] reduction effect, 3) Enhancement of autoignition due to the presence of H2O, 4) Enhancement or suppression of autoignition due to the presence of trace species such as unburned or partially-oxidized hydrocarbons.
The results show that the single-stage ignition fuels iso-octane and gasoline are more sensitive to the cooling effect of EGR, compared to the two-stage ignition fuels PRF80 and PRF60. On the other hand, the two-stage ignition fuels have much higher sensitivity to the reduction of O2 concentration associated with the addition of EGR. Furthermore, H2O has a pronounced ignition-enhancing effect for the two-stage fuels that tends to counteract the strong cooling effect of H2O. Finally, for the single-stage ignition fuels, gasoline and iso-octane, partially-oxidized fuel tends to enhance the ignition, thus counteracting the retarding effect of EGR. On the other hand, the trace species present for operation with the two-stage ignition fuel PRF80 increased the retarding effect of EGR.
In addition to the experiment, corresponding chemical-kinetics modeling was performed to evaluate the predictive capabilities of detailed iso-octane and PRF chemical-kinetics mechanisms from Lawrence Livermore National Laboratory (LLNL).
CitationSjöberg, M., Dec, J., and Hwang, W., "Thermodynamic and Chemical Effects of EGR and Its Constituents on HCCI Autoignition," SAE Technical Paper 2007-01-0207, 2007, https://doi.org/10.4271/2007-01-0207.
Homogeneous Charge Compression Ignition Engines, 2007
Number: SP-2100; Published: 2007-04-16
Number: SP-2100; Published: 2007-04-16
- Risberg, P., Kalghatgi, G., and Ångström, H.-E., “Auto-Ignition Quality of Gasoline-Like Fuels in HCCI Engines”, SAE Paper 2003-01-3215, 2003.
- Christensen, M., Johansson, B., Amnéus, P., and Mauss, F., “Supercharged Homogeneous Charge Compression Ignition”, SAE Paper 980787, 1998.
- Yao, M., Chen, Z., Zheng, Z., Zhang, B., and Xing, Y., “Effects of EGR on HCCI Combustion Fuelled with Dimethyl Ether (DME) and Methanol Dual-Fuels”, SAE Paper 2005-01-3730, 2005.
- Risberg, P., Kalghatgi, G., Ångström, H.-E., and Wåhlin, F., “Auto-Ignition Quality of Diesel-Like Fuels in HCCI Engines”, SAE Paper 2005-01-2127, 2005.
- Dec, J.E. and Sjöberg, M., “Isolating the Effects of Fuel Chemistry on Combustion Phasing in an HCCI Engine and the Potential of Fuel Stratification for Ignition Control”, SAE Paper 2004-01-0557, 2004.
- Kuo, T.-W., “Valve and Fueling Strategy for Operating A Controlled Auto-Ignition Combustion Engine,” presented at the SAE Homogeneous Charge Compression Ignition (HCCI) Symposium, San Ramon, CA, Sept. 24-26, 2006.
- Zhao, F., Asmus, T. W., Assanis, D. N., Dec, J. E., Eng, J. A., and Najt, P. M., Homogeneous Charge Compression Ignition (HCCI) Engines: Key Research and Development Issues, Society of Automotive Engineers, Warrendale, PA, 2003.
- Cooper, B., Jackson, N., Penny, I., Truscott, T., Rawlins, D., and Seabrook, J., “Advanced Development Techniques for Delivering Low Emissions Diesel Engines”, Proceeding of THIESEL 2006, pp. 267 - 280, 2006.
- Sjöberg, M. and Dec, J.E., “Smoothing HCCI Heat-Release Rates using Partial Fuel Stratification with Two-Stage Ignition Fuels”, SAE Paper 2006-01-0629, 2006.
- Sjöberg, M. and Dec, J.E., “EGR and Intake Boost for Managing HCCI Low-Temperature Heat Release over Wide Ranges of Engine Speed”, SAE Paper 2007-01-0051, 2007.
- Sjöberg, M. and Dec, J.E., “Combined Effects of Fuel-type and Engine Speed on Intake Temperature Requirements and Completeness of Bulk Gas Reactions in an HCCI Engine”, SAE Paper 2003-01-3173, 2003.
- Sjöberg, M. and Dec, J.E., “Comparing Late-cycle Autoignition Stability for Single- and Two-Stage Ignition Fuels in HCCI Engines”, Proceedings of the Combustion Institute, Vol. 31, pp. 2895-2902, 2007.
- Sjöberg, M., Dec, J.E., and Cernansky, N.P., “Potential of Thermal Stratification and Combustion Retard for Reducing Pressure-Rise Rates in HCCI Engines, based on Multi-Zone Modeling and Experiments”, SAE Paper 2005-01-0113, 2005.
- Sjöberg, M. and Dec, J.E., “Effects of Engine Speed, Fueling Rate, and Combustion Phasing on the Thermal Stratification Required to Limit HCCI Knocking Intensity”, SAE Paper 2005-01-2125, 2005.
- Sjöberg, M., Dec, J.E., Babajimopoulos, A., and Assanis, D., “Comparing Enhanced Natural Thermal Stratification against Retarded Combustion Phasing for Smoothing of HCCI Heat-Release Rates”, SAE Paper 2004-01-2994, 2004.
- Aroonsrisopon, T., Foster D.E., Morikawa, T., and Iida, M., “Comparison of HCCI Operating Ranges for Combinations of Intake Temperature, Engine Speed and Fuel Composition”, SAE Paper 2002-01-1924, 2002.
- Dec, J.E. and Sjöberg, M., “A Parametric Study of HCCI Combustion - the Sources of Emissions at Low Loads and the Effects of GDI Fuel Injection”, SAE Paper 2003-01-0752, 2003.
- Lutz, A. E., Kee, R. J., and Miller, J. A., “Senkin: A FORTRAN Program for Predicting Homogeneous Gas Phase Chemical Kinetics with Sensitivity Analysis,” Sandia National Laboratories Report No. SAND87-8248.
- Curran, H. J., Gaffuri, P., Pitz, W. J., and Westbrook, C. K., “A Comprehensive Modeling Study of Iso-Octane Oxidation,” Combustion and Flame, Vol. 129, pp. 253-280, 2002. www-cms.llnl.gov/combustion/combustion2.html
- Curran, H. J., Gaffuri, P., Pitz, W. J., and Westbrook, C. K., “A Comprehensive Modeling Study of n-Heptane Oxidation,” Combustion and Flame, Vol. 114, pp. 149-177, 1998.
- Pitz, W. J., Lawrence Livermore National Laboratory, Personal Communication, 2003.
- Heywood, J. B., Internal Combustion Engine Fundamentals, McGraw-Hill, New York, 1988.
- Naik, C.V., Pitz, W.J., Sjöberg, M., Dec, J.E., Orme, J., Curran, H.J., Simmie, J.M., and Westbrook, C.K., “Detailed Chemical Kinetic Modeling of Surrogate Fuels for Gasoline and Application to an HCCI Engine”, SAE Paper 2005-01-3741, 2005.
- NIST Chemistry WebBook, Standard Reference Database Number 69, June 2005 Release. http://webbook.nist.gov/chemistry/
- He, X., Donovan, M.T., Zigler, B.T, Palmer, T.R., Walton, S.M., Wooldridge M.S., and Atreya A., “An Experimental and Modeling Study of iso-Octane Ignition Delay Times under Homogeneous Charge Compression Ignition Conditions”, Combustion and Flame, Vol. 142, pp. 266-275, 2005.
- Shudo T., Kitahara, S., and Ogawa, H., “Influence of Carbon Dioxide on Combustion in an HCCI Engine with the Ignition-Control by Hydrogen”, SAE Paper 2006-01-3248, 2006.
- Aceves S.M., Flowers, D.L., Espinosa-Loza, F., Martinez-Frias, J., Dec, J.E., Sjöberg, M., Dibble R.W., and Hessel, R.P., “Spatial Analysis of Emissions Sources for HCCI Combustion at Low Loads Using a Multi-Zone Model”, SAE Paper 2004-01-1910, 2004.
- Kaiser, E.W., Maricq, M.M., Xu, N., and Yang, J., “Detailed Hydrocarbon Species and Particulate Emissions From An HCCI Engine as a Function of Air-Fuel Ratio”, SAE Paper 2005-01-3749, 2005.
- Särner, G., Richter, M., Aldén, M., Hildingsson, L., Hultqvist, A., and Johansson, B., “Simultaneous PLIF Measurements for Visualization of Formaldehyde-and Fuel- Distributions in a DI HCCI Engine”, SAE Paper 2005-01-3869, 2005.
- Dubreuil, A., Foucher, F., Mounaim-Rousselle, C., “Effect of Chemical Components, Amount and Temperature of the Exhaust-Gas-Recirculation on the Combustion Development in HCCI Mode”, Proceeding of THIESEL 2006, pp. 629 - 631, 2006.
- Risberg, P., Johansson, D., Andrae, J., Kalghatgi, G., Björnbom, P., and Ångström, H.-E., “The Influence of NO on the Combustion Phasing in an HCCI Engine”, SAE Paper 2006-01-0416, 2006.