Real-time Control of HCCI Engine Using Model Predictive Control

Abstract

Model Predictive Control (MPC) for combustion timing and load control of a single cylinder Homogeneous Charge Compression Ignition (HCCI) engine is designed and implemented. First, a nonlinear control oriented model is obtained based on a Detailed Physical Model (DPM) using model order reduction techniques. The model is then linearized around one operating point and combustion timing and output work prediction are experimentally validated. This linearized model is then used in MPC with Exhaust Valve Closing (EVC) timing and fueling rate as main actuators. Combustion timing is defined as the crank angle of fifty percent fuel mass fraction burned, and is calculated from cylinder pressure. The controller is verified in simulation using the DPM considering constraints on inputs and outputs. The controller is then directly implemented on a dSPACE MicroAutoBox for HCCI combustion timing and load control. For real-time implementation of the MPC, Laguerre functions are used to simplify the conventional MPC algorithm which reduces the computation time. The MPC tracks the desired load and combustion timing trajectories while considering constraints on the actuators and outputs in simulation and on the engine.