Oxygen sensor monitoring

摘要

A gas sensor deterioration monitor, particularly suited for use in an exhaust stream from an internal combustion engine. Under certain engine operating conditions, the output signal from the sensor is transformed through a Fourier Transformation into a frequency domain signal. Ratios of the magnitudes of certain odd and even harmonics are compared to corresponding reference values for a new sensor. Deviations beyond certain limits indicate a sensor that has deteriorated substantially.