Degradation diagnostic device of gas sensor and degradation diagnostic manner of gas sensor

摘要

PPROBLEM TO BE SOLVED: To provide the deterioration diagnosing device of a gas sensor for precisely diagnosing the deterioration of the gas sensor, and a method for diagnosing the deterioration of the gas sensor. PSOLUTION: The deterioration diagnosing device 10 of the gas sensor diagnoses the deterioration of the gas sensor 14 equipped with a detection element 14a for detecting the concentration of the specific gas in the exhaust gas flowing through the exhaust passage 22 of an internal combustion engine 2 and a heater 14b for heating the detection element 14a and has a diagnosing condition determining means (step S1) for determining whether a condition having to diagnose the deterioration of the gas sensor 14 is satisfied, a heater control means (step S3) for changing over the air/fuel ratio of the internal combustion engine 2 and starting the control of the power supply to the heater 14b when the condition having to diagnose the deterioration of the gas sensor 14 is determined to be satisfied, a response time measuring means (steps S4 and S5) for measuring the response time until the detection value of the detection element 14a becomes a predetermined value from the start of the control of power supply and a deterioration diagnosing means (step S6) for diagnosing whether the gas sensor 14 is deteriorated corresponding to the measured response time. PCOPYRIGHT: (C)2010,JPO&INPIT