Nonlinear control for joint air and fuel management in a SI engine

Engines equipped with a means to actuate air flow at the intake port can achieve superior fuel economy performance in steady state. The paper shows how modern nonlinear design techniques can be used to control such an engine over a wide range of dynamic conditions. The problem is challenging due to the nonlinearities and delays inherent in the engine model, and the saturation of the air flow actuator. The control solution has two novel features. Firstly, a saturation recovery method is directly integrated into the nonlinear control design. The second novel feature is that the control Lyapunov function methodology is applied to a discrete-time model. The performance of the controller is evaluated and compared with a conventionally controlled engine through simulations