| 摘要 |
PROBLEM TO BE SOLVED: To provide an exhaust emission control device for an internal combustion engine not causing thermal deterioration of an upstream catalyst due to excessive temperature rise even if the temperature of a downstream catalyst is raised to a required temperature by suppressing thermal conduction to a cooling part in a structure in which a plurality of catalysts is arranged in an exhaust pipe, an EGR passage is branched from between the catalysts, it is necessary to raise the temperature of the catalyst downstream of the EGR passage for maintaining an exhaust emission control function, and the cooling part exists on the EGR passage. SOLUTION: A thermal conduction suppressing part 62 is arranged in a part between the inlet of a low-pressure EGR passage 6 in the middle of the upstream catalyst 41 and the downstream catalyst 42 and an EGR cooler (cooling part) 61 to suppress thermal conduction to the EGR cooler 61. The thermal conduction suppressing part 62 is a non-metal member having lower thermal conductivity. The thermal conduction suppressing part may be a part formed into a shape having a thickness thinner than the pipe of the low-pressure EGR passage 6. The thermal conduction suppressing part may be a thin-walled metal seal sandwiched between flange parts. COPYRIGHT: (C)2009,JPO&INPIT
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