AFR control for motorcycle engine using smith predictor and h∞ control

This paper focuses on feedback control of the air-fuel ratio (AFR) for a motorcycle engine. A feature of this paper is to identify a simple model from the fuel injection time to the AFR, which captures the dynamics in various operating conditions. The model is composed of a single transfer function and a lookup table storing the gain and delay relative to the nominal model as functions of the engine speed, throttle position and water temperature. A compensator for changes of the delay is constructed using Smith predictor. An Hinfin controller is designed to handle unmodeled dynamics and disturbances. The effectiveness of the proposed method is investigated by experiments.