| 摘要 |
PURPOSE:To keep the temperature of a catalyst within a predetermined range of temperature by providing, upstream the catalyst, both a passage with a regenerator and a passage that bypasses the said passage and also providing a valve which switches the said passages to each other based on temperature of the catalyst. CONSTITUTION:An exhaust gas passage, which is situated upstream from the spot at which a catalyst 3 is situated, consists of both a regenerator-through- passage 5, which is provided wth a regenerator 4 introduces exhaust gas into the catalyst 3 through the regenerator 4, and a regenerator-non-through-passage 6, which introduces the exhaust gas into the catalyst 3 without making it pass through the regenerator 4. A control valve 9 which is able to switch the passages 5 and 6 to each other, is provided. Switching operation of this control valve 9 is controlled in such a manner that, based on temperature of the catalyst 3, the temperature of the catalyst 3 approaches a set value, which is in the predetermined range of temperature, via both a control circuit 10 and an actuator 12. |
