엔진 부하 및 마찰 토크를 보상하기 위한 승용 디젤엔진의 공회전제어기

Abstract

This study proposes the design of an idle speed controller to compensate for varying engine load and friction torque in passenger car diesel engines. An active disturbance rejection control (ADRC) framework, comprised of a disturbance compensator and a feedback controller, is applied to an idle speed controller to compensate for disturbances such as engine load and friction torque. The paper is composed of diesel engine modeling and controller design phases. In the modeling phase, we designed an engine speed model using the engine rotational dynamic, and then the model parameter was obtained from vehicle experiments. Using the model, the disturbance compensator and the feedback controller were designed in the controller design phase. The disturbance compensator consists of an observer-based compensator and a feedforward compensator. The observer-based compensator was designed to compensate for unmeasurable disturbances such as friction torque. In order to compensate measureable disturbances, the feedforward compensator was used. A proportional-derivative control structure was applied to the feedback controller to achieve satisfactory tracking performance and to reduce engine speed variation at a steady state. The proposed controller was validated by engine and vehicle experiments. For evaluation of the disturbance rejection performance, the engine load torque was changed while idling, and the results were compared with a commercial controller. The maximum fluctuation of the engine speed for the proposed controller is 2.26 times smaller than the commercial controller.