Abstract
The purpose of this study is to investigate the potential use of in-cylinder thermal and mixing stratification for reducing the pressure-rise rates in HCCI engines by going through numerical analysis with multi-zones modeling. The computations are conducted using both a standard single-zone and the custom multi-zone version of the Senkin application of the CHEMKIN II kinetics rate code, and kinetic mechanisms for Di-Methyl Ether (DME). The objective of calculation with the multi-zones model is to examine the mechanism of thermal and mixing stratified charge to reduce an excessive pressure-rise rates. The mechanism of reducing the pressure-rise rates in the thermal and mixing stratified charge is proved with 2-zones and 5-zones model. It is found that thermal and mixing stratification have the effect of reducing the pressure-rise rates (extended combustion duration) and have potential for extending the upper load limit in HCCI engines.
