Patent ID: 6694962
Filing Date: 2004-02-24
Classification: F02D,Y02T

Abstract:
An abnormality diagnosis apparatus of an internal combustion engine, comprising:an oxygen sensor for detecting a concentration of oxygen in exhaust gases of said internal combustion engine, said internal combustion engine having a plurality of cylinders; a plurality of injectors each provided on a corresponding set of said cylinders, respectively, for injecting fuel into said internal combustion engine; a feedback control element for driving said injector according to said concentration of oxygen to control an amount of fuel supplied to said internal combustion engine in a feedback manner; a forced fuel correction element for correcting an amount of fuel controlled by said feedback control element in a forced manner; and an abnormality determination element for determining the presence or absence of abnormality in said injector; wherein said abnormality determination element determines the presence or absence of abnormality in said injector based on said concentration of oxygen detected by said oxygen sensor in the course of a forced fuel correction control operation carried out by said forced fuel correction element, and wherein before determining the presence or absence of abnormality in said injector, said abnormality determination element determines the presence or absence of abnormality in said oxygen sensor based on said concentration of oxygen detected by said oxygen sensor in the course of the forced fuel correction control operation carried out by said forced fuel correction element, and further determines the presence or absence of abnormality in said injector only when said oxygen sensor is not abnormal.