PREDICTION OF HEAT-RELEASE PATTERNS FOR MODELING DIESEL ENGINE PERFORMANCE AND EMISSIONS

In the present paper phenomenological modelling has been adopted for modelling diesel engine processes considering heat losses, and variable specific heats using double-Weibe function for the heat release. High speed diesel fuel C10.8H18.7 is considered for calculations. Fuel injection timing engine speed, compression ratio, inlet charge pressure and temperature are observed to be pertinent parameters affecting diesel engine performance. Effect of exhaust gas recirculation on the formation and emission of oxides of nitrogen and soot density are also studied. Numerical experiments are performed by writing a computer code in C++ and heat release (both pre-mixed and diffusion phases), in-cylinder pressure and temperature histories and emissions are predicted. It was found that early injection timing leads to higher levels of pressure and temperature in the cylinder. It is observed that fuel injection timing and fraction of exhaust gas recirculation as critical factors in affecting engine performance as well as emissions