Modelling, Simulation & Analysis of Electro Magnetic Valve Actuator (EMVA) for Automotive System

摘要

Several variable valve-train technologies are being aggressively pursued to increase the efficiency of automotive engines. Electromagnetic Valve Actuation (EMVA) is a promising alternative that uses electromagnetic actuators to replace the conventional camshaft and aims to provide fully flexible valve timing control. This "camless" valve-train provides great opportunities for the automotive industry. In this study, we seek to develop a novel mathematical model for the EMVA system with the hope that great engineering insight will be unveiled for the system. To develop such a novel mathematical model firstly, we modelled the EMVA capturing the initial mode which is the same with that of the cam system. Secondly, we designed a PID controller with a set-point tracking scheme to capture the transition mode and holding mode . Simulation results in MATLAB/Simulink of the theoretical lift profile of the EMVA were imported into Curve Fitting Toolbox of MATLAB and the novel model was realized. Experimentally measured data for the lift profile were then fitted with this model and the experimental model realized varied from the theoretical one by just the number of terms. Thus, our novel lift profile model from experimental data was differentiated to give velocity, acceleration and jerk profiles of the EMVA in MATLAB/Simulink and in MAPLE. This created the platform for comparison of analytical and numerical results, using the analytical solution as the benchmark. Analytical and numerical comparisons of the mathematical models were done and invaluable scientific insight was gained for the systems as regards the landing velocity of the valve seat as it affects mechanical wear and high intensity noise during operation.