| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control device of an internal combustion engine capable of controlling an oxygen storage amount in a catalyst so that exhaust gases can be efficiently purified irrespective of whether an exhaust gas air-fuel ratio is rich or lean. <P>SOLUTION: First, it is determined whether the outputs of a first O<SB>2</SB>sensor 20 and a second O<SB>2</SB>sensor 22 are inverted to lean or not (steps 100, 102). When they are both inverted to lean, a rich control is performed (step 104). Next, it is determined whether the output of the first O<SB>2</SB>sensor 20 is inverted into rich or not (step 106). When it is determined to be inverted into rich, a lean control is started (step 110). The lean control is continued until the oxygen storage amount OSA<SB>1</SB>of the upstream side catalyst reaches a specified amount L<SB>1</SB>. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
