The acoustic hysteresis effect in KIVA during the combustion process of internal-combustion engines

Abstract

The heat release of a chemical reaction is a major source of combustion noise in internal-combustion engines. The simulation grid cells in the combustion chamber whose heat release changes as the crank angle changes serve as noise sources. These sources produce acoustic waves. By means of combining the acoustic theory and the KIVA program, the regions around the noise sources are divided into the cells inside the acoustic wave and the cells outside the acoustic wave respectively according to the range of acoustic wave propagation. Therefore the pressure of the cells are calculated on the basis of the cells lying in the different regions. The process of pressure oscillations in specific positions can be shown in the results. The characteristics of the main acoustic sources which caused the pressure oscillations can be analysed. On comparing the simulations and the experiments, the hysteresis effect of acoustic wave propagation can be taken into account when studying the combustion process in internal-combustion engines.