Investigation of combustion chamber thermal stratification effect on combustion performance of homogeneous charge compression ignition engine

Homogenous charge combustion ignition (HCCI) is an excellent method for higher efficiency and to reduce NOx and particulate matter simultaneously in comparison to conventional internal combustion engines. However، reaching for higher loads and improving combustion phasing control are important challenges for the HCCI research. In this study، thermal stratification using variable intake charge temperature، the EGR ratio and variable glow plug temperature have been investigated. A combination of experiments on single cylinder engine and the 3D simulation of combustion was used for this work. As a result، increasing intake charge and glow plug temperature advanced combustion timing، shortened ignition delay time and decreased the rate of heat release. Higher combustion efficiency and higher the allowable engine load could be obtained by the increase in the rate of EGR. In general، thermal stratification has the potential to extend high-load limits of HCCI combustion by improving the control over the combustion phase; as well as reducing the maximum rate of pressure rise.