| 摘要 |
PROBLEM TO BE SOLVED: To promote the warming-up of a catalyst and an internal combustion engine by controlling the opening/closing of a valve so as to vary the flow velocity distribution of exhaust gas flowing through an exhaust port. SOLUTION: The valve 500 is arranged in the exhaust port 300. By opening/closing the valve 500, the flow velocity distribution of the exhaust gas flowing through the exhaust port is varied. A heat insulation member 600 is provided on an upper portion of the inner peripheral surface 310 of the exhaust port 300. At the beginning of starting an engine 100, that is, during warming up the three way catalyst, the valve 500 is controlled to be closed so that the flow velocity of the exhaust gas flowing along the heat insulation member 600 may become larger than the case where the valve 500 is opened. After the warming-up of the three way catalyst is completed, and also during warming up the engine 100, the valve 500 is controlled to be opened. COPYRIGHT: (C)2006,JPO&NCIPI
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