Air/fuel ratio control using sliding mode methods

To meet demands for high performance and low fuel consumption and emissions, control of air/fuel ratio in spark ignition (SI) engines has received significant attention. Here, a nonlinear, fuel injected SI engine model is developed which includes intake manifold, fuel wall-wetting and crankshaft dynamics as well as load effects and process delays inherent in four-stroke engines. A sliding mode controller is designed and implemented for a linearized model using state estimates.