Electrical Variable Cam Phase Shifter for Internal Combustion Engine

This paper presents a new concept for an electro-mechanical cam phase shifting device (eCPS) along with its control structure. The proposed eCPS features a positive differential gear mechanism with a unique self-locking characteristic. Proof-of-concept simulations were performed using both ADAMS and Simulink analysis tools to evaluate the validity of the concept and its performance. Comparisons with other cam phasers were also discussed.

Results confirmed the frictional locking mechanism which not only allows for reduced control effort but also provides the system with an important fail-operational feature. The frictional locking mechanism significantly reduces the reliability burden upon the electric machine. It was indicated that eCPS compares favorably with hydraulic cam phasers in shifting range, position holding, slew rate, system stiffness and power consumption. The performance of eCPS is independent from engine performance characteristics and environmental conditions.