Method for detecting deterioration of an air-fuel ratio sensor.

摘要

A method of detecting deterioration of an air-fuel sensor which is used for controlling an air-fuel ratio of an engine, comprising the steps of detecting minimum value of a flame resistance in a combustion chamber of said engine in one cycle of combustion; calculating a mean value of the detected minimum values of the flame resistance for a plurality of cycles of combustion; obtaining a reference air-fuel ratio based on the mean value and predetermined data as to a relation between a minimum value of the flame resistance and an air-fuel value ratio; comparing the reference air-fuel value with the air-fuel ratio obtained by said air-fuel sensor to obtain a difference; and judging the deterioration of said air-fuel sensor based on the difference. <IMAGE>