| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To highly accurately detect malfunction of a channel selector means without any special part. <P>SOLUTION: The malfunction of the channel selector valve 15 disposed in a branched part of a main passage 9a and a bypass passage 9b is determined based on an integration value CTEX of differenceΔTEX(TEX1-TEX2) of exhaust temperatures TEX1, TEX2 which are detected by a first exhaust temperature sensor 25 downstream of a junction of an exhaust pipe 9 and a second exhaust temperature sensor 26 of an exhaust bypass passage 9b. In a start mode where the channel selector valve 15 closes the bypass passage 9b, the expression TEX1>TEX2 is satisfied to increase the integration value CTEX. In a normal mode, where the channel selector valve 15 closes the main passage 9a, the expression TEX1<TEX2 is satisfied to decrease the integration value CTEX. When the channel selector valve 15 is closed and fixed to the main passage 9a, the temperature differenceΔTEX becomes a negative value even in the start mode to decrease the integration value CTEX. Further, when the channel selector valve 15 is closed and fixed to the bypass passage 9a, the temperature differenceΔTEX becomes a positive value even if the mode is transited to the normal mode to increase the integration value CTEX. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
