Study on Mixture Formation of Liquid LPG for a Center Injection DISI Engine

Abstract

Center injection in pentroof combustion chamber can reduce wall wetting and unburned hydrocarbon emission in wall guided combustion system, which is generally employed in DISI (Direct Injection Spark Ignition) engines. Once liquid phase LPG (Liquefied Petroleum Gas) is injected at a high pressure, flash boiling occurs severely, promotes mixing and reduces wall wetting in wall guided engine. Based on validating the feasibility of the models, this paper numerically simulates the mixing process of a center injection wall guided DISI engine in different conditions. The results show that a stratified charge can obtained at part load with late injection, whereas at high load the early injection can achieve a homogeneous mixture at the end of compression stroke.