Transient control of gasoline engines with C/GMRES

The oil crisis and strict emission legislation have greatly motivated the development of internal combustion engine technology. To improve fuel economy performance and reduce emissions, engine transient control has attracted wide research interests. However, engine system is a nonlinear physical plant with constraints on itself and actuators, and also it is a sophisticated control system involving many control loops to achieve single or multiple objectives. Therefore it is really a challenging issue on the transient control of the engine. In recent years, receding horizon control (RHC) was gained much attention in the field of engine control, owing to its advantages that it can explicitly tackle the constrained optimization and multi-variable control problem. However, a remarkable drawback of RHC is the heavy computation load for on-line optimization algorithm, especially for the nonlinear control system. Indeed, this bottleneck restricts its practical implementation on the industrial electronic controller of a fast control system for a long time. This tutorial paper proposes a systematic receding horizon controller design approach for the transient control applications of the gasoline engines. Two independent RHC-based tracking controllers aimed to achieve the engine torque and speed tracking control are designed, respectively. The control oriented model is derived from the mean-value model of gasoline engines, meanwhile the integrator of the tracking error is embedded to improve the tracking accuracy. All the proposed controllers are verified in real-time on a full-scale gasoline engine and the on-line optimization algorithm for RHC adopts C/GMRES method, which can provide an approximately optimal solution by solving the linear equation instead of the Riccati differential equation. The experimental results demonstrate a large potential for improving the engine transient control performance with RHC scheme.