A numerical simulation method was developed and applied for improving the new direct injection gasoline engine. The method consists of a spray wall impingement model, a combustion model based on the unburnt and burnt gas temperatures and a solution based local grid refinement technique. This method was applied for the analysis of the fan-shaped spray combustion system under late injection conditions. The following results were obtained: 1) Almost the same results were obtained in about one-third the CPU time compared to with the conventional method, 2) the calculated spray pattern, mixture formation and combustion processes are in good agreement with the measurements, and 3) The advantage of the mixture formation of the fan spray system became clarified. The eddy induced by the fan spray forms a mixture suitable for combustion with the least amount of overly lean mixture.
�@