Valve Timing by Means of a Rotary Actuator

This paper will discuss the design and simulation of an electro-mechanical valve timing (EMVT) system for IC engines. The system consisted of a rotary actuator for converting an electric signal to rotary motion and a rocker arm to convert the rotary motion to valve movement. The design of this system included specifying the characteristics of the rocker arm, the actuator's armature moment of inertia, the field windings and the controller.

The simulation of the complete system was done using the Advanced Continuous Simulation Language (ACSL) to execute a model that consisted of a controller in a feedback loop with a bond graph model of the actuator and rocker arm. The simulation showed the motion of the valve as a function of actuator input voltage and time for various engine speeds. Performance was measured by the overall time the valve was opened and a comparison was made with an existing valve systems. It was hoped that the outcome of the simulation work would demonstrate the feasibility of this device using realistic values for the physical parameters in the model.