Study on Influence of Deformation on the End Face Leakage of a Small Wankel Rotary Engine

A temperature field model of a small Wankel rotary engine was established by the finite element method with cylinder pressure, temperature and heat transfer coefficient under the ideal condition as initial boundary conditions. The result of the temperature field calculation was checked by experiment. The initial value of gas leak and the leakage area were acquired from the deformation calculation performed based on the checked temperature field result. Then the boundary conditions were then updated by considering leakage, and the final leakage at end faces was obtained by cyclic simulation with the new boundary conditions. Finally, the influence of the engine speed on the end faces leakage was studied with the method above. The results show that the leakage area reaches the maximum value when the crank angle is about 630°, and the maximum leakage area decreases in quasi-linear with the increase of the engine speed. The leakage rate reaches the maximum at near top dead center, where the leakage is about 50% of the total. Furthermore, the leakage rate decreases with the increase of the engine speed, while the crank angle corresponding to the maximum leakage rate decreases as the engine speed increases.