EXHAUST GAS SENSOR FAILURE DIAGNOSIS APPARATUS

摘要

The present invention relates to an exhaust gas sensor abnormality diagnostic device and provides an exhaust gas sensor abnormality diagnostic device that is capable of accurately diagnosing an abnormality caused by a broken element of an exhaust gas sensor. The exhaust gas sensor abnormality diagnostic device includes an exhaust gas sensor, judgment means which judges whether execution conditions are established for making an abnormality diagnosis of element breakage in the exhaust gas sensor, and abnormality diagnosis means which, when the execution conditions are established, makes the abnormality diagnosis in accordance with an output signal generated by the exhaust gas sensor. During a lean period during which the air-fuel ratio of exhaust gas is lean, the judgment means judges that the execution conditions are not established. Further, while the integrated value of intake air amounts of an internal combustion engine is not smaller than a predetermined value, the judgment means judges that the execution conditions are established. The abnormality diagnosis means cancels the establishment of the execution conditions when an intake air amount of the internal combustion engine remains not greater than a predetermined value for a predetermined period of time.