| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an abnormality detecting device of a reducer addition valve, restraining output lean shift of an air-fuel ratio detecting means to detect abnormality of an addition valve with good accuracy. <P>SOLUTION: When abnormality of an exhaust fuel addition valve is detected, an instruction is given to reduce an addition quantity per injection as compared with catalyst regeneration, and increase the frequency of injection, and add a reducer (step 102). After that, an addition quantity of the reducer added from the exhaust fuel addition valve is measured based on the air-fuel ratio sensor output (step 104). the proportion R of the measured addition quantity to the instructed addition quantity is calculated (step 1-6), and when the proportion R is outside the reference range, the exhaust fuel addition valve is determined to be abnormal (step 112). <P>COPYRIGHT: (C)2008,JPO&INPIT |
