Static performance of a polarized permanent-magnet reluctance actuator for internal combustion engine valve actuation

This paper describes the topology of a permanent-magnet polarized reluctance actuator that enhances the performance of electromagnetic valve actuation systems; specifically, it reduces losses during extended periods of valve closure, improves controllability, provides a degree of fail-safe operation in the event of a system fault, and reduces currents required for system initiation during cold-starting of the engine. The paper describes the basic operating mechanism of the actuator and explains the influence of various design features on its static characteristics by means of a finite-element-based design study on a representative performance specification. A prototype device has been manufactured and its static characteristics have been measured experimentally to illustrate the utility of the proposed actuator topology and the key findings from the design study.