| 摘要 |
<P>PROBLEM TO BE SOLVED: To keep the conversion rate of a main catalyst high even if a main catalyst is not in a stoichiometric state at an early stage of a process changing a channel change over valve and making an exhaust gas flow only to a main exhaust gas passage. <P>SOLUTION: An exhaust device includes a demand output means (31) outputting a close demand before the main catalyst (8) is activated and an open demand when the main catalyst (8) is activated, and a means (31) retarding to give the channel change over valve (4) the open demand until output of a second air-fuel ratio sensor (47) is changed over to stoichiometric when the output of the second air-fuel ratio sensor (47) is not stoichiometric and the demand output means outputs the open demand while exhaust gas is made flow to bypass channels (11, 13) by the close demand from the demand output means. <P>COPYRIGHT: (C)2010,JPO&INPIT |
