Advanced sliding mode idle speed control for a nonlinear engine model: coordinated throttle/spark advance control

The engine idle speed should be as low as possible for reduced fuel consumption. But, since idle speed is set at a low value, even slight fluctuations of the idle speed due to torque disturbances cause not only deterioration of vehicle performance but also unpleasant vibrations of the vehicle. Therefore, the primary goal of the idle speed control is to maintain a desired engine speed despite torque disturbances. In this paper, the coordinate throttle/spark advance control using a sliding mode scheme is designed for nonlinear engine speed control which has superior ability to minimize idle speed variations under rapid torque disturbances and the system nonlinearities/uncertainties