Three-Dimensional Modeling of Combustion Process, Soot and NOx formation In a Direct-injection Diesel Engine

This paper is presented to study the combustion process and emissions in a direct injection diesel engine. Computations are carried out using a three-dimensional model for flows, sprays, combustion and emissions in Diesel engines. Interactions between combustion and emissions with flow field are considered and it is shown that soot mass fraction increases at regions with low turbulence intensity and fuel rich zones. Impingement of spray with the piston walls is also modeled by Wall-jet functions and is shown that soot mass fraction tends to increase at impinging zones. Also in high temperature areas where Air Fuel Ratio (AFR) nears unity and oxygen is available, NOx mass fraction will increase. Results of this model show a good agreement with the corresponding data in the literature.