Model-Based Control of Electromagnetic Valve Actuators for Engine Speed Control

Abstract

The introduction of electromagnetic valve actuators (EMVA) benefits engine fuel economy, torque performance and reduction of emissions. Meanwhile, it complicates the controller for the purpose of regulating the additional freedom degrees of intake valvetrain, such as valve lift, opening timing and opening duration. In order to address the control issue of EMVA application, a model-based controller is needed to realize that the cylinder air charge is regulated by controlling the EMVA motion directly for controlling the engine speed and output torque. For the development of the controller, a control-oriented model of engine with EMVA that can simulate the intake process of unthrottled operation, torque generation and crankshaft rotational dynamics was first developed. Then a model-based EMVA controller was designed to regulate the actuation of electromagnetic intake valves which consisted of a feedforward and a PID feedback module. According to torque-based concept, engine speed reference was translated into torque demand using optimal control theory and the speed control problem was solved as two parts: torque management that decided torque demand and the torque demand tracking. The simulations carried out in Matlab/Simulink verified the effectiveness of the controller. In addition, a test platform of the EMVA for hardware-in-the-loop (HIL) simulation was established and the practicability of EMVA application to engine intake systems was validated preliminarily.