Patent ID: 6487851
Filing Date: 2002-12-03
Classification: F01N,F02D,Y02A,Y02T

Abstract:
An exhaust emission control device of an internal combustion engine, comprising:an exhaust emission purification catalyst device provided in an exhaust passage of the internal combustion engine, and having an NOx decreasing function of purifying or occluding NOx in an exhaust gas when an exhaust air-fuel ratio is a lean air-fuel ratio, and a reducing function of reducing hazardous substances in the exhaust gas when the exhaust air-fuel ratio is one of a stoichiometric air-fuel ratio and a rich air-fuel ratio; NOx detection means for detecting or estimating a concentration of NOx released into an atmosphere; and control means for computing a total NOx discharge by integrating a momentary NOx discharge released into the atmosphere after measuring a predetermined driving period of a vehicle based on an output from the NOx detection means, and stopping or suppressing an operation at a lean air-fuel ratio when detecting or expecting that a total NOx discharge exceeds a predetermined value before a vehicle reaches a predetermined driving period.