SIMULATION ANALYSIS OF THE EFFECT OF INLET PIPE DIAMETER ON THE CYLINDER FILLING OF COMPRESSION-IGNITION ENGINE

In this paper are presented the basic problems accompanying the flow of charge through compression-ignition engine inlet system. The flow of medium through inlet pipe to cylinder was assumed to be one-dimensional and described with mass, momentum and angular momentum conservation equations and energy conservation law. On the other hand, a zero-dimensional model described by mass-energy conservation equations was used to determine parameters of the medium in total cylinder volume. Simulations were carried out with the use of numerical programme in which McCormack’s explicit method was applied to solve differential equations describing the flow of charge in inlet system. The McCormack explicit technique was used due to the fact that an earlier attempt at solving a numerical problem with the method of lines had not yielded desired effects in view of high instability. Simulation aimed at determining the mass of air remaining in engine cylinder after inlet valve closure. Simulation results are presented in the form of in-cylinder air mass versus crank angle characteristics for different inlet pipe diameters. The study results are also presented in the form of a summary table and a summary diagram, the latter enabling a comparison of results for different inlet pipe diameters