Effects of Piston Cavity Configuration on In-cylinder Flow and Mixture Formation of a DI Diesel Engine

摘要

Effects of piston cavity configuration on in-cylinder flow and mixture formation were investigated using high-speed photography and 3-dimensional computation analysis. The following points have been clarified. (1)In a deep-bowl cavity with squish lip, strong reverse squish flow pushes away almost all mixture into the squish area. (2)In a moderate reentrant-type cavity with bottom protrusion, the major fuel vapor is confined within the cavity up to the middle stage of combustion, where the mixing and oxidation are promoted by a spiral flow generated by combination of swirl and squish flows.