Simulation of a Free Piston Linear Engine fueled with LPG

This paper presents a simulation research about free piston linear engine (FPLE) fueled with LPG include 30% propane and 70% butane. Dynamic model, linear alternator model and thermodynamic model are used as the numerical models to predict motion of piston, in-cylinder pressure and generated electric power of FPLE. The spark timing and air gap length are changed to provide information for the prediction. The result of this research is divided by two parts include motoring mode and firing mode. The result at motoring mode showed that there is validation between simulation and experiment for volume and pressure in cylinder. In regard to firing mode, by increasing spark timing, the velocity of piston, peak pressure and electric power increase respectively. Beside, by increasing air gap length, the velocity of piston change insignificantly, however both the peak pressure and electric power decrease respectively.