Two-zone chemical kinetics modeling of a gasoline HCCI engine

The effects of various direct gasoline injection strategies on homogeneous charge compression ignition(HCCI) combustion were studied using a two-zone high octane number gasoline HCCI combustion model based on the Chemkin source code.The temperatures,pressures,and species concentrations are coupled in the two zones.The model includes heat transfer and blow-by sub-models and the detailed chemical kinetics and physics of the combustion control by the stratified mixture.The two-zone model shows better agreement with experimental results than the single-zone model.The high pressure peak of the single-zone model is avoided and the combustion region is extended.Use of the two-zone model to analyze the effect of gas concentration stratification on the HCCI combustion shows that the controlled heat release reduces the pressure increase and extends the operating region so that the HCCI combustion can be controlled by adjusting the fuel ratio between the two zones.