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Some Evidence for Chemical Effects on Octane Requirement Increase from Deposits in Spark Ignition Engines
ISSN: 0148-7191, e-ISSN: 2688-3627
Published May 01, 1997 by SAE International in United States
Annotation ability available
The octane requirement increase (ORI) observed in spark ignition engines essentially occurs due to the effect of deposits in the combustion chamber changing the heat transfer characteristics between the end-gas and the combustion chamber walls. In addition, the volume occupied by deposits produces a change in compression ratio inside each cylinder which also contributes to ORI. However, all the ORI observed in spark ignition engines cannot be explained by these physical effects alone and for some time the existence of a chemical mechanism of ORI has been postulated. Evidence is presented from a laboratory experiment which demonstrates that deposits are indeed able to influence the ignition delay times of fuel-air mixtures by providing a source of active species which help initiate autoignition. Such effects have also been observed in some engine experiments, thus confirming the existence of chemically based ORI.
CitationPrice, R., Beck, C., and Morley, C., "Some Evidence for Chemical Effects on Octane Requirement Increase from Deposits in Spark Ignition Engines," SAE Technical Paper 971668, 1997, https://doi.org/10.4271/971668.
SAE 1997 Transactions - Journal of Fuels and Lubricants
Number: V106-4 ; Published: 1998-09-15
Number: V106-4 ; Published: 1998-09-15
- Kalghatgi, G.T., “Deposits in gasoline engines - A literature review”, SAE Paper No. 902105, 1990.
- Kalghatgi, G.T., “Combustion chamber deposits in spark ignition engines - A literature review”, SAE Paper No. 952443, 1995.
- Konig, G. and Sheppard, C.G.W., “End gas autoignition and knock in SI engines”, SAE Paper No. 902135,1990.
- Pan, J. and Sheppard, C.G.W., “A theoretical and experimental study of the modes of end gas autoignition leading to knock in S.I. engines, SAE Paper No. 942060, 1994.
- Co-ordinating Research Council (CRC) Report No. 531, “Octane requirement increase of 1980 model cars”, 1982.
- Callison, J.C., Wusz, T. and Biller, W.F., “Trends in octane number requirements (ONR) increase”, SAE Paper No. 892036, 1989.
- Benson, J.D., “Some factors which affect octane requirement increase”, SAE Paper No. 750933,1975.
- Heywood, J.B. “Internal combustion engine fundamentals”, McGraw Hill Book Co., 1988.
- Warren, J.D. “Combustion chamber deposits and octane requirement”, SAE Trans. 62583,1954.
- DeGregoria, A.J. “A theoretical study of engine deposits and its octane requirement using an engine simulation”, SAE Paper No. 820072,1982.
- Graiff, L.B., “Some aspects of deposit effects on engine octane requirement increase and fuel economy”, SAE Paper No. 790938,1979.
- Eng, K.D., Carlson, C.A, Hayden, T.E. and Sung, RL., “Engine test procedures to evaluate octane requirement increase and intake system cleanliness, SAE Paper No. 892122,1989.
- Alquist, H.E., Holman, G.E. and Wimmer, D.B., “Some observations of factors affecting ORI”, SAE Paper No. 750932,1975.
- Kalghatgi, G.T., McDonald, C.R and Hopwood, A.B., “An experimental study of combustion chamber deposits and their effects in a spark-ignition engine”, SAE Paper No. 950680, 1995.
- Cowart, J.S., Keck, J.C., Heywood, J.B., Westbrook, C.K. and Pitz, W.J., “Comparison of engine knock predictions using a fully-detailed and reduced chemical kinetic mechanism”, Paper Presented at the Western States Section of Combustion Institute, Livermore, CA, October 23-24, 1989.
- Kalghatgi, G.T. “Combustion chamber deposits and knock in a spark ignition engine - some additive and fuel effects”, SAE paper No. 962009, 1996.
- Brussovansky, S., Heywood, J.B. and Keck, J.C. “Predicting the effects of air and coolant temperature, deposits, spark timing and speed on knock in spark ignition engines”, SAE Paper No. 922324, 1992.
- Lu, J., Gupta, A.K., Pouring, A.A. and Keating, E.L., “A preliminary study of chemically enhanced autoignition in an internal combustion engine, SAE Paper No. 940758, 1994.
- Minetti, R., Carlier, M., Ribaucour, M., Therssen, E. and Sochet, L.R., “A rapid compression machine investigation of oxidation and auto-ignition of n-heptane: Measurements and modelling”, Combustion and Flame, 102 (3), pp298-309, 1995.
- Affleck, W.S. and Thomas, A., “Opposed piston rapid compression machine for preflame reaction studies”, Proc. Inst. Mech. Eng., 183 (1), pp365-387, 1969.
- Griffiths, J.F., Jiao, Q., Kardylewski, W. Schreiber, M., Meyer, J. and Knocke, J.F. “Experimental and numerical studies of di-tert-butylperoxide combustion at high pressures in a rapid compression machine, Combustion and Flame, 93, pp303-315,1993.
- Park, P. and Keck, J.C. “Rapid compression machine measurements of ignition delays for primary reference fuels, SAE Paper No. 900027, 1990.
- Price, RJ., Wilkinson, J.P.T., Jones, D.A.J. and Morley, C. “A laboratory simulation and mechanism for the fuel dependence of SI combustion chamber deposit formation”, SAE Paper No. 952445,1995.
- Shore, L.B. and Ockert, K.F., “Combustion chamber deposits - A radiotracer study”, SAE Trans., vol. 66, pp285-294, 1958.
- Prabhu, S.K., Li, H., Miller, D.L. and Cernasky, N.P., “The effect of nitric oxide on autoignition of a primary reference fuel blend in a motored engine”, SAE Paper No. 932757, 1993.
- Watson, C.W., Shell Research Ltd., Thornton Research Centre, personal communication.
- Jensen, RS., Korcek, S., Zinbo, M. and Johnson, M.D., “Initiation of hydrocarbon autoxidation at elevated temperatures”, Int. J. Chem. Kinet., 22(10), pp1095-1107, 1990.