A New Phenomenological Model for Combustion and Performance Studies of Direct Injection Diesel Engines

A computer simulation of a four-stroke turbocharged diesel engine has been developed for combustion and performance studies. The combustion model accounts for spray geometry evolution, ignition delay, heat release rate, equilibrium product concentrations and heat transfer evaluation. In the model, the fuel spray is divided into five zones which are treated as open systems. While mass and energy equations are solved for each zone, a simplified momentum conservation equation is used to calculate the amount of air entrained into each zone. Details of the DI spray, combustion model and its implementation into the open cycle simulation are described in this paper. The model is validated by experimental data. First, prediction of spray penetration is validated against measurements in a pressurized constant volume chamber. Subsequently, predictions of heat release rates are compared with experimental data obtained from representative heavy-duty, turbocharged diesel engine and single cylinder engines. It is demonstrated that the model can predict the rate of heat release and engine performance with high accuracy.