| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control device for reducing a specific substance discharged together with exhaust gas, by raising the temperature of a catalyst in a short period of time, when starting an internal combustion engine, without causing a pressure loss and upsizing of a physical constitution. <P>SOLUTION: An orifice part 40 arranged in an exhaust passage 41 controls the cross-sectional area of the exhaust passage 41 and a flow of the exhaust gas in the exhaust passage 41 by adjusting opening of a first valve member 44 and a second valve member 47. When the temperature of a three-way catalyst 32 is low, the orifice part 40 introduces the flow of the exhaust gas to a part on the outer peripheral side of the three-way catalyst 32. Thus, when the temperature of the three-way catalyst 32 is low, the exhaust gas is introduced to a part of the three-way catalyst 32, and the temperature of the three-way catalyst 32 rises in a short period after starting an engine body 13. The orifice part 40 expands the cross-sectional area of the exhaust passage 41 as the temperature of the three-way catalyst 32 rises, and fully opens the exhaust passage 41 when the temperature of the three-way catalyst 32 reaches the active temperature. Thus, the exhaust gas is introduced to the whole of the three-way catalyst 32, and the pressure loss is reduced. <P>COPYRIGHT: (C)2009,JPO&INPIT |
