Diagnosis of on-board sensors in internal combustion (IC) engines.

An efficient method of sensor diagnosis in electronically controlled internal combustion engines is presented. The approach taken is based on the failure detection and isolation (FDI) theory. The resulting diagnostic systems can be implemented in onboard digital computers of passenger vehicles. The proposed diagnostic system, referred to as the binary phase detection filter (BPDF), uses a pair of failure-sensitive filters. Based on the reference model of the given internal combustion engine, the BPDF not only isolates an individual failed sensor, but also can closely estimate the level of failure. Hence, BPDF enables detection of a wide variety of sensor failures including soft partial types (e.g. calibration or bias drift).