An Analytical Approach for the Optimization of a SI Engine Performance Including the Consideration of Knock

The present contribution describes an analytical approach for predicting the highest limit for acceptable power or efficiency for any spark ignition engine while ensuring knock free operation. A deterministic gradient based model combined with a simple genetic algorithm were used in association with a two-zone engine combustion model to predict analytically the necessary changes in specified operating parameters to produce optimum performance. Various examples involving mainly spark ignition engine operation with methane-hydrogen fuel mixtures are presented and discussed.