Three-Dimensional Numerical Analysis of In-Cylinder Flows in Reciprocating Engines

This paper describes the results of the three-dimensional numerical analysis of swirl behavior in the cylinders and piston cavities of reciprocating engines under motoring conditions. The generation of swirl during intake stroke has been calculated in one model engine having an off-center intake valve and a flat piston. Furthermore, in the other model engine having a piston with a cavity whose configuration has been changed variously, the decay of swirl during compression stroke has been calculated.

The results show that the process of induction swirl generation varies considerably with the inflow velocity distribution around the intake valve, and that in the cases of non-axisyrametric corolla-like cavities the swirl decays much more greatly than in the cases of axisymmetric cavities.