Title: Analysis on cycle-by-cycle variation of combustion from pressure indicator data

Authors: H. Nohira, T. Konomi, S. Ishiyama

Addresses: Higashi-Fuji Technical Centre, Toyota Motor Co. Ltd., Susono, Shizuoka, Japan. ' Higashi-Fuji Technical Centre, Toyota Motor Co. Ltd., Susono, Shizuoka, Japan. ' Higashi-Fuji Technical Centre, Toyota Motor Co. Ltd., Susono, Shizuoka, Japan

Abstract: An indicator analyser has been developed capable of statistical analysis from pressure data from each cylinder of a multi-cylinder engine under steady state conditions by an on-line mini-computer. This analyser is able to acquire engine data under transient conditions as well and to perform interlocutory analyses of any specified combustion cycle utilizing an off-line large computer. Analysis on the causes of cycle-by-cycle variation of combustion has been made and a simple relationship has been derived therefrom such that the variance of indicated mean effective pressure may be broken down into three terms such as variances of released heat and change of internal energy and their co-variance. Experiments revealed that the variance of released heat manifests some characteristics related to the fuel supply system and that of change of internal energy manifests some characteristics related to the pattern of heat released in the cylinder, but the interpretation of the physical significance of the co-variance term remains to be solved. This method is found to be a useful one for analysing the causes of cycle-by-cycle variation of combustion and its improvement in actual engines.

Keywords: internal combustion engine; engine design; thermodynamics; heat transfer; combustion cycle; fuel mixture; transient engine conditions; steady-state engine conditions; exhaust emissions; emission control; multi-cylinder engines; mean effective pressure; cylinder pressure data; internal energy; released heat pattern; ignition time control; online computer; statistical analysis; digital computer.

DOI: 10.1504/IJVD.1980.061357

International Journal of Vehicle Design, 1980 Vol.1 No.2, pp.131 - 142

Available online: 25 May 2014 *

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