Quiet Seating Control Design of an Electromagnetic Engine Valve Actuator

The control of engine valve seating velocity has been identified to be crucial for the application of an electromagnetic valve (EMV) actuator for camless variable valve timing engine operations. Analysis shows that the EMV actuator becomes unstable when the engine valve is hold steady close to the seating position. As such, valve motion under open loop control is sensitive to disturbances and suffers poor repeatability. Therefore, closed-loop control is required to achieve desirable quiet-seating performance consistently. A linear plant model was constructed based on a gray-box approach that combines mathematical modeling and system identification. A controller was developed with H∞ loop-shaping method to stabilize the EMV actuator. The performance of this control design is demonstrated by experimental results. “Seating velocity” and “seating tail-length” are defined and used to evaluate the control system performance.