MONITORING METHOD OF OXYGEN SENSOR

摘要

PROBLEM TO BE SOLVED: To provide a method for detecting and quantitatively determining the deterioration with the lapse of time of an oxygen sensor. SOLUTION: This monitoring method for gas sensor is particularly suitable for the use in the exhaust flow from an internal combustion engine. In a certain engine operating condition, the output signal from a sensor 22 is converted into a frequency area signal by Fourier transformation. The ratio of absolute values of certain even and odd-order harmonic waves is compared with a corresponding value with respect to a new sensor. The slippage exceeding a certain limit shows a rather deteriorated sensor.