| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a catalyst deterioration determination device for performing the determination of a catalyst deterioration capable of giving an alarm to notify a user of the deterioration of a catalyst device consisting of a plurality of catalysts serially arranged in the exhaust passage of an internal combustion engine at a proper timing. <P>SOLUTION: This catalyst deterioration determination device is applied to the internal combustion engine having a first catalyst, a second catalyst and a third catalyst serially arranged in the exhaust passage in the increasing order of the distance from an exhaust port 34. The maximum oxygen storage quantity Cmax(1), Cmax(2) or Cmax (3) of each catalyst is estimated based on the output of an air-fuel ratio sensor in the upstream of the first catalyst and the output of an air-fuel ratio sensor in the downstream of each catalyst, and the deterioration index value Ke(1), Ke(2) or Ke(3) of each catalyst changed according to the maximum oxygen storage quantity of each catalyst is calculated. Based on the comparison result of an index value for catalyst deterioration determination obtained by mutually multiplying each deterioration index value with a standard value for catalytic device deterioration determination, it is determined whether the catalyst device consisting of the first, second and third catalysts is deteriorated or not. <P>COPYRIGHT: (C)2004,JPO</p> |
