Control of intake manifold pressure for lean-burn motorcycle engine

Applying lean burn for motorcycle engines is a preferred solution to reduce fuel consumption and exhaust pollutants. It is however difficult to use conventional air/fuel control solutions for a lean-burn engine as the fuel duration is controlled to achieve desired torque, while airflow is controlled by the throttle valve to maintain air/fuel ratio demand. So for lean-burn motorcycle engine, the throttle valve must be automatically controlled depending on airflow requirement. However airflow cannot be controlled directly by throttle position due to high error. Since the airflow is closely related to the manifold pressure, this paper proposes an adaptive controller for pressure intake manifold control of a motorcycle engine using an electronic throttle valve control. The throttle position is employed as the control input for maintaining desired intake manifold pressure, and is designed based on a lead-lag compensator. The speed-density solution is employed to estimate the parameter of dynamic model. The root-locus technique is used to design the adaptive controller. Performance of the proposed controller is evaluated using a nonlinear motorcycle engine model in matlab/Simulink and experimental validation.