Prediction of HCCI engine performance with Three Zone Extended Coherent Flame Combustion model

Abstract

: Soot, NOx paradox in compression ignition engines is an extremely challenging issue. Low temperature combustion followed by Homogeneous charge compression ignition (HCCI) type of combustion is capable of reducing nitrogen oxides and soot simultaneously. Homogeneous charge compression ignition (HCCI) has a potential for high fuel conversion efficiency and extremely low emissions of particulate matter and oxides of nitrogen (NOx). However, feasibility of HCCI is also posing certain issues .In this paper, three zone extended coherent flame combustion model of STAR-CD package has been used to study the CI engine in both conventional and HCCI mode. A comparison of important parameters like in-cylinder pressure, temperatures, CO, NOx emissions, in conventional and HCCI mode are predicted. Relatively Low in-cylinder pressures and temperatures are realized in HCCI mode when compared to conventional mode of combustion. Uniform mixing of fuel-air, turbulent kinetic energy and velocity contours are obtained in HCCI mode