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This paper describes an analysis of the induction and exhaust processes of the spark ignited engine. The analysis has been combined with an overall engine simulation to provide greater flexibility in studying the effects of induction/exhaust related parameters on engine emissions and fuel economy. Results are presented to illustrate the use of the engine model in predicting engine behavior in non-conventional configurations such as engine load control using an early intake valve closing technique.

A method is presented for determining an optimum engine calibration that maximizes fuel economy for the CVS-H cycle subject to a set of emission constraints. The method combines the results of a powertrain simulation with steady state engine dynamometer emissions and fuel flow data to project cycle emission and fuel economy values. Dynamic Programming is used to allocate emission contributions among selected speed/load points to maximize projected cycle fuel economy. The corresponding engine calibration is then directly inferred from the optimum emission allocation. Typical results for 2.3 liter and 400 CID engines are presented.