| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve performance of an exhaust emission control device by making an orifice structure independent from a secondary air supply control and enhancing temperature rise effect by opening control according to exhaust gas temperature during secondary air supply. <P>SOLUTION: In the exhaust emission control device for the engine, when warming-up is confirmed S11-S13 based on accelerator opening APO and water temperature Tw, supply of secondary air is started in step S14 and it is determined whether the exhaust temperature Tex reaches a temperature rise reversing threshold temperature Texth or not in step S15. The threshold temperature Texth is a temperature rise effect reversing threshold at which a high and low relation of the exhaust temperature when flow of exhaust gas is choked by an orifice structure and the exhaust temperature when flow of exhaust gas is not choked reverses. When it is determined that the exhaust temperature Tex reaches the threshold temperature Texth or higher in the step S15, the opening V of the orifice structure is increased in step S17. Flow speed of exhaust gas sent to an exhaust emission control catalyst is increased by increasing the opening V, and oxidation is promoted to raise the exhaust temperature more. <P>COPYRIGHT: (C)2007,JPO&INPIT |
