Design of a 3-stage voltage controller for EMV actuation in SI engines

It was proven that variable valve timing used in the SI engines could have obvious benefits on high fuel economy, low exhaust emission, and good engine performance. Electromagnetic valve (EMV) offers very high flexibility in valve timing. With EMV system in an SI engine, the valve timing can then be adjusted adaptively according to any engine operating situations, and each cylinder can have different settings for valve timing. Since the EMV runs very fast, there are problems of vibration and noise due to the impact between valve and valve seat. To improve these problems this paper presents two control methods to perform soft-land control. One is a fuzzy logic controller to control the movement of EMV. The other one is a novel 3-stage voltage control method which aims to get optimal real-time control for EMV. Simulation results show the fuzzy logic controller provides lower impact velocity (0.4m/s), while the optimized 3-stage voltage controller offers simple control and acceptable performance.