Energy-Based Key-On Control of a Double Magnet Electromechanical Valve Actuator

The aim of this paper is to design, analyze, and validate via experiments the control of a double magnet electromechanical valve actuator (EMVA). Such actuators have shown to be a promising solution to actuate engine valves during normal engine cycle. Their use can increase engine power, reduce fuel consumption and pollutant emissions, and improve significantly engine efficiency. To this aim, this actuator needs to be properly controlled at the engine startup for the first valve lift (key-on control). Mathematically, the EMVA system can be described as a highly nonlinear piecewise-smooth mechanical oscillator. The proposed control law is based on an energy control approach. Bifurcation analysis of the closed-loop system is carried out to characterize the nonlinear dynamics of the valve and to tune the controller. The numerical and theoretical analysis is in good agreement with the experimental results.