Residual Gas Fraction Measurement in Spark Ignition Engines

To meet future pollutant emissions standards, it is crucial to be able to estimate the composition of the combustion chamber charge on a cycle by cycle basis. 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.