Lyapunov-based constrained engine torque control using electronic throttle and variable cam timing

In this paper, predictive control of a spark ignition engine equipped with an electronic throttle and a variable cam timing actuator is considered. The objective is to adjust the throttle angle and the engine cam timing in order to reduce the exhaust gas emissions while maintaining fast and monotonic transient engine torque response. To this end, using a mean-value nonlinear model for the air intake system of the engine, a receding horizon control scheme based on a flexible control Lyapunov function is developed. The proposed control scheme can adjust the throttle plate angle and the cam timing to provide a fast and monotonic air flow response into the engine cylinders, while explicitly taking into account constraints. Compared to a previous parameter governor controller, the simulation results show that the proposed solution provides better performance in terms of settling time. Moreover, the computational complexity of the algorithm is compatible with current electronic control units, despite using a full nonlinear model.