An Optimum Flexible Linkage Design of a Fully Variable Electromechanical Valve Actuation System for Internal Combustion Engines

Abstract

In this study, the mechanical design of a fully flexible valve actuation system (FFVA) for intake valves of naturally aspirated internal combustion engines is optimized. The original FFVA design used a connecting rod in order to transform the rotating motion of the actuator to translating motion of the valve. In the improved design introduced here, the connecting rod is replaced by a flexible linkage. This step is taken in order to eliminate wear and play in the mechanical connections. A detailed design procedure is presented to optimize the heavy fatigue load on this element. Simulations and experimental tests are carried out in order to validate the system performance. It is shown that valve trajectory and energy consumption of the actuation system obtained by simulations are consistent with those observed experimentally. The present redesigned FFVA system then provides more reliable valve motion than previously shown designs.