Offset-free model predictive control of diesel engine by combined design of disturbance model and observer

The diesel engine is a typical multi-input multi-output system with strong couplings, actuator constraints, and fast dynamics. The control objective is to operate the engine to meet driver's speed demand and reduce exhaust emissions of nitrogen oxides during transient processes. Interactions between the actuators and nonlinear behavior of the system make the problem difficult to handle using classical control design methods. Therefore, we propose an offset-free model predictive control system in this paper. It is based on the combined design integrating the disturbance model and the state observer. Furthermore, the method of reduced-order design for H_∞ problem is addressed. The proposed approach has low computation requirement and is suitable for implementation in the engine control unit on board. The application of this system in a continuous working process by using dSPACE MicroAutoBox verifies its feasibility and effectiveness for achieving precise reference tracking of engine speed and reducing emissions.