| 摘要 |
<P>PROBLEM TO BE SOLVED: To accurately detect deterioration of a storage reduction type NOx catalyst without causing deterioration of fuel economy. <P>SOLUTION: NOx quantity Gs which can be stored by a criterion catalyst which is on a boarder of deterioration and normal is supplied to a storage reduction type NOx catalyst, reducer quantity Hs corresponding to the NOx quantity is supplied by rich spike then, and deterioration of the NOx catalyst is judged based on output Cr of a NOx sensor at that time. Since deterioration of the NOx catalyst is judged based on magnitude of output of the NOx sensor, accurate deterioration diagnosis can be executed, and deterioration of fuel economy can be prevented since excessive reducer is not supplied while the catalyst is normal. <P>COPYRIGHT: (C)2008,JPO&INPIT |
