Study on a control-oriented model of boosted HCCI engine and control simulation

With the aim of achieving stable homogeneous charge compression ignition (HCCI), it is necessary to estimate in-cylinder states and control it. Present automotive engines are basically controlled by look-up tables. They require a huge number of experiment results. On the other hand, there are some works in which model-based control method is proposed on behalf of look-up tables. Model-based control uses control-oriented model considering physics, and is expected to reduce number of experiment results and to improve transient driving performance. The control-oriented model discretizes engine cycle into some representative points, and the computational load of the model is small enough to calculate on board. In this work, a control-oriented model of a boosted HCCI engine is constructed and a control system is designed based on the model. The control system is composed of Kalman filter, feed forward controller and feed-back controller. In the control system, the cylinder states is defined as the state variables, observed by the Kalman filter. The control system adapts to the target IMEP and boost pressure by the gain scheduling method. Then, the performance of control system is examined by simulation, in which the plant model is the control-oriented model considering the sensors and actuators noise and the model-error. The results shows that IMEP and maximum pressure rise rate (MPRR) tracks the target to some extent by the feed forward controller and the feed-back controller absorbs the tracking error of MPRR caused by the model-error.