Patent ID: 6295807
Filing Date: 2001-10-02
Classification: F01N,F02D,Y02T

Abstract:
An exhaust gas purifying catalyst deterioration detecting system for an engine including an air/fuel ratio sensor disposed upstream of a catalyst for purifying an exhaust gas and an oxygen sensor disposed downstream of said catalyst, said system comprising:saturation determining means for determining saturation of said catalyst on the basis of an output of said downstream oxygen sensor;first calculation means for calculating an amount of gas component flowing into the catalyst based on the output of said upstream air/fuel ratio sensor;second calculation means for calculating an amount of gas component flowing out of the catalyst based on the output of said downstream oxygen sensor;saturation correcting means for correcting the amount of gas component flowing out of the catalyst determined by said second calculation means, on the basis of the output of said upstream air/fuel ratio sensor when the saturation of said catalyst is determined by said saturation determining means; andcatalyst deterioration detecting means for detecting the deterioration of said catalyst on the basis of the amount of gas component flowing out of the catalyst corrected by said saturation correcting means and the amount of gas component flowing into the catalyst determined by said first calculation means.