A Model for Residual Gas Fraction Prediction in Spark Ignition Engines

To meet future pollutant emissions standards, it is crucial to be able to estimate the cycle by cycle composition of the combustion chamber charge. This charge consists of fresh air, fuel and residual gas from the previous cycle. Unfortunately, the residual gas fraction cannot be directly measured.

Therefore, a model of residual gas fraction as a function of engine parameters and operating parameters has been developed. The model has been calibrated with exhaust pipe hydrocarbon measurements using a successive dilution method.