CONTROL-ORIENTED MODEL OF A DUAL EQUAL VARIABLE CAM TIMING SPARK-IGNITION ENGINE

A control-oriented engine model is developed to represent a spark igni ted engine equipped with a variable cam timing mechanism over a wide r ange of operating conditions. Based upon laboratory measurements a con tinuous, nonlinear, low-frequency phenomenological engine model is dev eloped. With respect to a fixed-cam timing engine, the VCT mechanism a lters the mass airflow into the cylinders, the torque response, and th e emissions of the engine. The developed model reflects all of these m odifications and includes a representation of the breathing process, t orque and emission generation, and sensor/actuator dynamics. The model has been validated with engine-dynamometer experimental data and can be used in powertrain controller design and development.