Design of a 3-Stage Voltage Controller for EMV Actuation in SI Engines

Variable valve timing (VVT) provides SI engines several significant benefits in fuel economy, exhaust emission, and engine performance. Among all VVT mechanisms, electromagnetic valve (EMV) is a positive one by providing very high flexibility in valve timings and possibility of cylinder-by-cylinder VVT control. This paper presents a simple 3-stage voltage control method for EMV actuation to effectively reduce the contact velocity between EMV and valve seat. A voltage pattern for EMV actuation is derived first by a fuzzy logic controller. Then, this pattern is simplified into 3 level voltage in which the voltage magnitude and duration are analyzed and optimized. Simulation results show that the 3-stage voltage controller offers simple control algorithms and acceptable performance with low impact velocity