On-Board Diagnosis of Emission Control System Malfunctions in Electronically Controlled Spark Ignition Engines

This paper discusses simulation and experimental results of a study aimed at diagnosing faults associated with an automotive engine exhaust emissions control system. Parity space methods are applied to a model of the engine intake, fueling, combustion and exhaust dynamics to diagnose faults in sensors and actuators used by the exhaust emissions control system. The results indicate that a mix of linear and nonlinear models permit the design of an effective diagnostic strategy.