Patent ID: 8260576
Filing Date: 2012-09-04
Classification: F02D,G01N

Abstract:
1. An exhaust gas sensor abnormality diagnostic device comprising: an exhaust gas sensor which is positioned in an exhaust path of an internal combustion engine, includes a sensor element positioned between external air and exhaust gas, and generates an output signal correlated with the oxygen partial pressure difference between the external air and the exhaust gas; judgment means which judges whether execution conditions are established for making an abnormality diagnosis of element breakage in the exhaust gas sensor; detection means which, when the execution conditions are judged to be established, detects an output signal generated by the exhaust gas sensor during a subsequent period during which an air-fuel ratio of exhaust gas is lean; abnormality diagnosis means which, when the detected output signal is a negative voltage signal, judges that the exhaust gas sensor is abnormal due to a broken element thereof; and cancellation means which 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.