Computer Simulation of Combustion Characteristics of MPFI Engine

Most of the current fuel supply specifications, including the key parameters in the fuel control strategies, are experimentally determined. Since the complexity of fuel flow behavior inside the intake manifold is still not quantitatively understood the objective of this study is to evaluate the performance characteristics of Multi Point Fuel Injected (MPFI) SI engine using computer simulation. This paper describes a complete model of the intake port, taking into account physical evaluation of three phases in a bi-dimensional geometry. Back flow of hot burned gases, droplet trajectories, droplet evaporation and airflow has been developed to gain a better understanding of the fuel flow behavior within the intake manifold, which may help to determine the fuel supply specifications in a Multi Point Injection system. A mathematical model is developed to synthesis a pressure diagram from the engine geometry and the air fuel mixture strength. A program code to evaluate the performance characteristics of the Multi Point Fuel Injected engine is developed. This code predicts the heat release, pressure, power, torque and efficiency developed inside the combustion chamber for various operating parameters. The program for this model consists of two main programs, which are written, in C language. The results obtained from the simulation conform to the existing trend.