Internal combustion engine intake manifold dynamics

A mathematical model of a four-stroke four-cylinder internal combustion engine is presented. In this model the throttle valve, plenum, intake and exhaust valves and cylinder motion are modeled to predict instantaneous and averaged values for the intake air flow and manifold pressure. Comparison of simulation and experimental results show a good agreement. From this model the manifold pressure pulsation amplitude and settling time can be determined. The average intake flow and manifold pressure can be used to generate a volumetric efficiency plot for the engine. Experimental data from three different engines confirm the accuracy of the model. Optimal sizing is suggested for different engines based upon parametric ratios. This mathematical model for the volumetric efficiency plot can be used for scheduling a fuel injection system without having to make experimental measurements of an engine.