A NUMERICAL AND EXPERIMENTAL-STUDY ON THE OPTIMAL-DESIGN FOR THE INTAKE SYSTEM OF THE MPI SPARK-IGNITION ENGINES

A computer program has been developed to predict the engine performanc e characteristics through the analysis of the flow in the intake and e xhaust systems and of the cylinder combustion phenomena for the MPI sp ark ignition engines. Using the program, a study for the optimal desig n of the intake system has been performed by varying the factors which can influence the volumetric efficiency, such as the volume of the pl enum chamber, the length of the intake manifold and the pipe length be tween the surge tank and the plenum chamber. Experimental tests have a lso been carried out to obtain the transient pressure history in the i ntake manifold and the cylinder, and the variations of volumetric effi ciency over the various engine speeds. The result of simulation has be en compared with that of experimental test, and the optimal design dat a for the test engine could be found. The comparison of volumetric eff iciency shows good agreement between the simulation and experiment.