| 摘要 |
<P>PROBLEM TO BE SOLVED: To more accurately suppress the thermal deterioration of a purifying means. <P>SOLUTION: A bypass passage 25 is connected to a main passage 21 in which a first catalyst is provided, and a bypass valve 40 is provided in the bypass passage 25. On the first catalyst 31, a floor temperature detecting sensor 51 is provided for detecting a floor temperature. In an exhaust pipe 10, a gas temperature detecting sensor 52 is provided for detecting a gas temperature as exhaust gas temperature. During operating an internal combustion engine 1, the floor temperature detecting sensor 51 and a floor temperature acquiring part 62 of an ECU 60 are used for acquiring the floor temperature of the first catalyst 31, and the gas temperature detecting sensor 52 and a gas temperature acquiring part 63 of the ECU 60 are used for acquiring the gas temperature. When the bypass valve 40 is opened, a gas temperature comparing part 65 of the ECU 60 compares the gas temperature with the floor temperature. In accordance with the comparison, when the gas temperature is lower than the floor temperature, the bypass valve 40 is closed and exhaust gas whose temperature is lower than the floor temperature flows in the first catalyst 31. As a result, the thermal deterioration of a catalyst 30 as the purifying means is more accurately suppressed. <P>COPYRIGHT: (C)2007,JPO&INPIT |
