Numerical calculation of gas exchange in two-stroke engine for aircraft

Abstract

General aviation light aircrafts and unmanned aerial vehicles are equipped mainly with internal combustion piston four-stroke and two-stroke engines. Despite of the significant amount of research and development works, the ways of the further performance improving for such engines are nearly exhausted. However, there are fundamentally new developments, which combine the advantages of four-stroke valvetrains with the two-stroke cycle, which provides significant increasing of the engine performance. This article presents the results of computational studies of a Rotax 914 four-stroke aircraft engine, modified to the two-stroke cycle. The calculations were carried out with the software named Diesel-RK, which made it possible to select the optimal engine settings, mostly timing, and software AVL FIRE for 3D numerical simulation of cylinder scavenging through valves to confirm the residual gas amount in cylinder with such type of gas exchange. The calculations confirmed the possibility of increasing performance of the engine almost in 1.5 - 2 times for the entire operating speed speed, which is confirmed by experimental results published in the known open articles.