Patent ID: 9488123
Filing Date: 2016-11-08
CPC Classification: F02D,Y02T

Claim Text:
1. An internal combustion engine diagnosing apparatus for identifying a malfunctioning cylinder having an abnormal air-fuel ratio as a failure occurrence among a plurality of cylinders of a multicylinder internal combustion engine while the internal combustion engine is in operation, comprising: an air-fuel ratio controller for controlling the respective cylinders such that a value of an air-fuel ratio of one of the cylinders in stable operation is changed to increase or decrease sequentially stepwise with one cylinder at a time in order, by controlling a fuel injection quantity adjusting unit for adjusting respective fuel injection quantities of the cylinders, the value of the air-fuel ratio to be changed to increase or decrease sequentially stepwise is predetermined in a program; and a malfunctioning cylinder identifier for identifying the malfunctioning cylinder based on a relationship between the respective numbers of misfires of the respective cylinders which are counted by a misfire counter with respect to each of the values of the air-fuel ratios which are changed stepwise, and the air-fuel ratios which are changed stepwise.