| 摘要 |
<P>PROBLEM TO BE SOLVED: To surely remove foreign matter and an unburnt fuel component from exhaust air introduced into an exhaust air recirculating passage, in a constitution having a main passage and a bypass passage. <P>SOLUTION: The main passage is composed of an upstream side main passage 2, an intermediate main passage 3 and a downstream side main passage 7, and has a directional control valve 4 for opening and closing the main passage, and a main catalytic converter 8 is interposed on the downstream side. A bypass catalytic converter 18 having first and second catalysts 18a and 18b is interposed in the bypass passage composed of an upstream side bypass passage 11, an intermediate bypass passage 14 and a downstream side bypass passage 16, and the exhaust air recirculating passage 20 is connected to intermediate clearance 19 between the first and second catalysts 18a and 18b. When opening the directional control valve 4, the exhaust air flows backward to the exhaust air recirculating passage 20 from the downstream side main passage 7, and passes in the inverse direction through the second catalyst 18b even in this case, so that the foreign matter and the unburnt fuel component are removed from the recirculating exhaust air, and fouling of an intake system is avoided. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
