| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control device of an internal combustion engine for suppressing deterioration of the emission, by suppressing unpurified exhaust gas from flowing into a main catalyst when a main exhaust pipe and the main catalyst are not directly communicated with each other. <P>SOLUTION: This exhaust emission control device 1 of the internal combustion engine has a bypass device 2 arranged on the upstream side of the main catalyst. The bypass device 2 comprises the main exhaust pipe 4 into which the exhaust gas flows, a front-stage auxiliary catalyst 5 arranged between the main exhaust pipe 4 and a housing 3, an exhaust gas inflow pipe 7 into which the exhaust gas flowing from the front-stage auxiliary catalyst 5 flows, a rear-stage auxiliary catalyst 6 arranged between the exhaust gas inflow pipe 7 and the housing 3, and a valve 8 for changing flow of the unpurified exhaust gas in the main exhaust pipe 4. When the end 4a of the main exhaust pipe 4 is blocked by the valve 8, the pressure in an exhaust gas inflow chamber 9 formed of the main exhaust pipe 4 and the exhaust gas inflow pipe 7 is lower than the pressure in the main exhaust pipe 4 and higher than the pressure in the housing on the downstream side of the rear-stage auxiliary catalyst 6. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
