Abstract
Charge Stratification has been thought as one of the ways to avoid the sharp pressure rises of HCCI combustion. The purpose of this study is to evaluate the potential of equivalence ratio, initial temperature, and EGR Stratifications to reduce Pressure Rise Rate on HCCI combustion. Pre-mixture with stratifications is charged into Rapid Compression Machine. After that, the pre-mixture is compressed and in that process, in-cylinder gas pressure and temperature are analyzed. Additionally numerical calculation with multi-zones model is run to know the potential of equivalence ratio, initial temperature, and EGR stratifications for reducing Pressure Rise Rate. This study investigates to expect the degree of stratification of in-cylinder charge shown in real engine from single-zone model. For clearly verifying the degree of stratification of in-cylinder charge, the results from single-zone model are compared with those from multi-zone model. The considered types of stratification of in-cylinder charge are thermal stratification, fuel stratification and EGR stratification. The comparison results between single-zone model and multi-zone model show that EGR stratification was most effective to disperse ignition timing compared to the thermal stratification and fuel stratification when setting the same time differences of ignition timing shown in single-zone model. Among the results from three type of stratification of in-cylinder charge, fuel stratification was the worst on disperse of ignition timing.
