Multi-input transient fuel control with auto-calibration

Most engine transient fuel control methods use the mass of injected fuel to drive the compensator dynamics. This works well in conventional engines because several other main factors that affect the fuel puddle, such as mass air-flow and manifold air pressure (MAP), are coupled closely with the injected fuel. In variable cam timing (VCT) engines, MAP and mass of injected fuel are decoupled to the point that they may move in opposite directions under certain conditions. To circumvent this problem we propose using MAP as the second input to compensate for fuel puddle dynamics. The structure of the new compensator is derived from a detailed model of the puddle dynamics. Further, we provide a method to automatically fit the new model and compensator parameters from dynamometer data. The model and compensator performance is illustrated by simulations and experiments.