| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a diagnostic device for an exhaust gas cleaning catalyst, highly reliably, highly accurately, and frequently performing catalytic diagnosing processing, while maintaining preferable emission. <P>SOLUTION: The diagnostic device for an exhaust cleaning catalyst diagnoses a degree of deterioration in performance of a NO<SB>x</SB>catalyst for cleaning exhaust disposed to an exhaust system of an engine. The diagnostic device comprises: a program (a step S14) determining whether or not a temperature of the NO<SB>x</SB>catalyst is within a diagnosis enabling range before the catalytic diagnosing processing; and a program (a step S142) controlling the temperature of the NO<SB>x</SB>catalyst to be within the diagnosis enabling range before the catalytic diagnosing processing when it is determined that the temperature of the NO<SB>x</SB>catalyst is out of the diagnosis enabling range in the step S14, are provided. <P>COPYRIGHT: (C)2008,JPO&INPIT |
