Air-Fuel Ratio Transient Control Design for Gasoline Engines Based on Individual Cylinder Air Charge Estimation

For spark-ignition gasoline engines, the air-fuel ratio during transient operation is an important index concerning the emission performance and the torque generation quality, and the challenge is from the dynamics of air intake path, the fuel injection path and the sensor delay. This paper presents a simple model of intake dynamics-based air-charge estimation for the individual cylinder air charge. Then, with the model, a feed-forward based air-fuel ratio control law is developed in which the intake dynamics and the sensor delay are taken into account by introducing the cylinder air-charge prediction. The proposed control strategy is validated by the experiment results conducted on a commercial vehicle-used six-cylinder gasoline engine control test-bench.