Simulation of the sweep and compression process of a two-stroke crankless internal combustion engine using a CFD model
Abstract
The air exchange and motion of the free piston linear engine (FPLE) are closely related and affect the intake efficiency during the engine start-up process. In this study, a computational fluid dynamics (CFD) simulation model was built based on the actual FPLE model with two 25cc twin-cylinder engines. The piston start-up strategy was move at two speeds of 0.32 m/s and 0.64 m/s. The results showed that the intake efficiency at a speed of 0.32 m/s was 78% and the intake efficiency at a speed of 0.64 m/s was 54%. The final pressure of the compression process at a speed of 0.32 m/s was 4.7 kg/cm2, and at 0.64 m/s it was 3.9 kg/cm2. Based on the results of the final pressure of the compression stroke, the engine can successfully ignite and start-up in one piston stroke.
