Fully coupled control of a spark-ignited engine in driving cycle simulations

The fuel consumption of vehicles with spark-ignited (SI) gasoline engines in transient driving cycles depends greatly on the thermodynamics and its interplay with the calibration of the engine control. For the simulation of these complex phenomena covering engine physics and applied control, a new methodology is presented. A functional model of the engine control unit is introduced together with a driver control. It is coupled to a physical modeling framework consisting of a crank angle-based engine model and a vehicle drivetrain model. As a key feature, a novel predictive SI combustion sub-model is integrated, using quasi-dimensional modeling approaches for flame propagation, turbulence, and ignition delay. In a modular validation process, each sub-model and its interaction in the coupled simulation environment are evaluated successfully. The fully coupled model is then used to predict the fuel consumption in driving cycles under varying calibration strategies of the engine control.