Patent ID: 6842690
Filing Date: 2005-01-11
Classification: F02D,F02M,Y02T

Abstract:
1. A failure detection apparatus for an internal combustion engine, comprising: fresh air quantity detecting means arranged in an intake system of the engine, for detecting a quantity of fresh air introduced into a combustion chamber of the engine; fresh air quantity reference value setting means for setting a reference value for the fresh air quantity in accordance with an operating state of the engine; failure detecting means for detecting abnormality of said fresh air quantity detecting means, based on a result of comparison between the fresh air quantity detected by said fresh air quantity detecting means and the reference value set by said fresh air quantity reference value setting means; an EGR passage for allowing part of exhaust gas to be recirculated from an exhaust system of the engine to the intake system as EGR gas; an EGR valve inserted in said EGR passage, for controlling a quantity of the EGR gas by varying an opening thereof; target opening setting means for setting a target opening for said EGR valve in accordance with the operating state of the engine such that an air-fuel ratio or excess air ratio of the exhaust system becomes equal to a predetermined value corresponding to the operating state; and EGR valve control means for controlling said EGR valve in accordance with the target EGR valve opening set by said target opening setting means, wherein said fresh air quantity reference value setting means sets the reference value in accordance with not only the operating state of the engine but also the target EGR valve opening set by said target opening setting means.