Simulation Analysis On Matching And Dynamic Characteristic Of Turbocharging System For Gasoline Engine

Turbocharging is the most effective measure for enhancing engine's power and improving the economy. Environmental conditions have special requirements of power recovery for aeroengine in high altitude, while supercharger technology is an important measure of the aeroengine's power recovery. At present, the turbo technology of small aviation piston engine has been mature abroad, but domestic are committed to the research. The ROT AX 914 gasoline engine is the research object in this paper. This paper investigates the matching between GT25 turbocharger and gasoline engine, the matching between JK48 turbocharger and gasoline engine, and the dynamic characteristics of control system.On the basis of selecting turbocharger, the matching model between GT25 and gasoline engine, the matching model between JK48 turbocharger and gasoline engine and the simulation model of control system were set up in MATLAB/Simulink. Considering that the compressor performance does not change with the altitude, the matching simulation of engine and compressor was discussed in different altitudes.Laws of matching between GT25 turbocharger and gasoline engine are determined. The MAP of valve position, which is changed with engine speed and altitude, is obtained. Effects of volumetric efficiency and excess air ratio on the laws of matching between GT25 turbocharger and gasoline engine were studied.The matching between JK48 variable geometry turbocharger and ROTAX 914 gasoline engine is studied. Laws of matching between JK48 turbocharger and gasoline engine are determined. The MAP of vane position, which is changed with engine speed and altitude, is obtained. Effects of volumetric efficiency and turbine efficiency on the laws of matching between JK48 turbocharger and gasoline engine were analysed.The application of PID control of turbocharging system is studied. Results show that the control system has better characteristics in a certain moment of inertia of the load such as responsibility, accuracy and stability. Effects of control algorithm on the dynamic characteristics of control system were studied. Different performance of control system in integral separation PID algorithm and in general PID algorithm was analysed. Effects of inertia moment on the control system performance were studied.The results can provide some analysis foundation for turbocharger selection, matching between turbocharger and gasoline engine, and design of the control system in the R&D process of four-stroke piston aircraft engine.