FUEL INJECTOR MODELLING

Abstract

Fuel injector is one of the most important subsystem of compression ignition engines as most of the engine characteristics like power output, specific fuel consumption and pollutant emissions depend upon the injection conditions. Owing to the importance of injector unit, a need is felt to develope a computer model for fuel injection system calculations to be used in our existing combustion model. In the present work, the model for the most extensively used jerk pump (inline) type fuel injection system (considered to consist of pump, pipe and nozzle) has been developed. The equation at the pump and the nozzle ends are solved by applying finite difference scheme and using Newton-Raphson method. The transient behaviour of the fluid in the pipe line is predicted by using the method of characteristics. The influence of various parameters like pipe friction, leakage at the pump, pressure effect on fuel density and bulk modulus, and the delivery valve mechanical clearance is considered in the analysis. The individual effects of the important parameters affecting fuel injector performance are studied and the predictability of the model is demonstrated in the work presented here