Cycle-to-cycle fluctuation in combustion of diluted mixture in a spark-ignition engine (2nd report, simulation of combustion fluctuation)

Cycle-to-cycle fluctuation in combustion of a lean mixture and a nitrogen-diluted in a spark-ignition engine was investigated. From the results given in the first report, it was clarified through experimentation that the duration of 1% combustion was a dominant factor for determining the fluctuation of mean effective pressure. In this study, the fluctuations of 1% combustion duration and indicated mean effective pressure were computed as the function of fluctuations both in the equivalence ratio of the mixture and in the turbulence characteristics of the cylinder charge. The computed results were in good agreement with the experimental results obtained under well-controlled conditions of mixture composition in the cylinder.