Patent ID: 8234916
Filing Date: 2012-08-07
Classification: F02D,Y02T

Abstract:
1. An abnormality diagnosis device for an air-fuel ratio sensor detecting an air-fuel ratio in exhaust gas in a compression ignition type internal combustion engine comprising: calculation air-fuel ratio calculating means for calculating a calculation air-fuel ratio based upon at least a fuel injection quantity and an intake air quantity in the internal combustion engine; and abnormality determining means for determining abnormality of the air-fuel ratio sensor based upon the calculation air-fuel ratio and an actual air-fuel ratio detected by the air-fuel ratio sensor, when an operating condition in the internal combustion engine relatively rapidly changes according to an engine operating demand and thereby the calculation air-fuel ratio relatively rapidly changes, wherein the abnormality determining means determines the abnormality of the air-fuel ratio sensor when the operating condition in the internal combustion engine relatively rapidly changes from a steady condition, and makes correction for making the calculation air-fuel ratio equal to the actual air-fuel ratio when the calculation air-fuel ratio and the actual air-fuel ratio become in a steady condition during the steady condition of the internal combustion engine.