Intelligent air/fuel ratio control strategy with a PI-like fuzzy knowledge–based controller for gasoline direct injection engines

This paper proposes a new concept of PI-like fuzzy knowledge–based controller with self-tuning capability, high robustness and rapid development capability to regulate air/fuel ratio for gasoline direct injection engines. The proportional and integral terms of the PI-like fuzzy knowledge–based controller are nonlinear functions of the input signals and self-tuned in real time at operation points, which can reduce the effort spent on calibrating controller parameters. The PI-like fuzzy knowledge–based controller is implemented on a production gasoline direct injection engine and evaluated through case studies. The experimental results show that the proposed controller can regulate air/fuel ratio at stoichiometric value with less settling time and less oscillation compared with the conventional Proportional-Integral (PI) controller for transient operation.