Advanced model-based diagnosis of internal combustion engines

Abstract

Model-based methods allow to detect and diagnose faults earlier and more detailed compared to classical limit checking and plausibility checks of directly measurable signals. The effect of faults by using signal models is, e.g. shown in changes of their frequencies or amplitudes. Process models allow using changes of the input-output behavior expressed by their parameters, state variables, or parity equations. This was illustrated for categories or groups of a diesel engine in form of the intake system, the injection system, and the turbocharger. Some results were also summarized for a direct injection gasoline engine. Corresponding methods can be developed for the combustion and mechanics and for the exhaust gas aftertreatment. Integrating the faultdetection results of all categories allows a comprehensive fault-diagnosis coverage of diesel engines and similarly for gasoline engines in addition to the known OBD functions.