Modeling of the thermal behavior and the diagnostic systems of a SI engine

Abstract In this paper, a model of the thermal on board diagnostic system of a BMW spark ignition engine is presented. At first, the model of the thermal system including the engine itself and several heat exchangers is set up as a simulation environment for the diagnosis. The engine is divided into a combustion model and a three-zone heat transfer model. In a second step, the diagnosis function for the coolant temperature sensor is implemented as an example of a thermal on board diagnosis function.