Nonlinear adaptive idle speed control design for SI engines

The paper proposes a nonlinear adaptive control strategy to deal with idle speed control for spark ignition (SI) engines. Focusing on rejecting the load disturbance during idling operation, an adaptive speed controller for throttle, combined with a delay compensation by spark advance (SA), is designed based on the nonlinear mean-value engine model. To deal with the performance interaction of the air-fuel ratio to the idle speed, a novel fuel injection control strategy is integrated with the speed control loop. The robustness of the idle speed control is demonstrated by numerical simulation first. Experimental testing on an engine test bench demonstrates the effectiveness of the control strategy.