| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent the activity of a catalyst from degrading by preventing an exhaust gas at low temperatures from being guided to an exhaust emission control device by a simple configuration. <P>SOLUTION: This catalyst cooling prevention device of an exhaust emission control device includes a low-pressure loop EGR device 28 comprising a recirculating flow passage 26 for connecting the outlet of a turbine 2b with the inlet of a compressor 2a and a control valve 27 installed in the recirculating flow passage 26, an exhaust brake 25 installed in an exhaust passage 11 between the low-pressure loop EGR device 28 and the exhaust emission control device 14, an engine control device 34, a gas thermometer 30 for detecting the gas temperature at the outlet of the turbine 2b, a catalyst temperature detection means 31 for detecting the temperature of the oxidation catalyst 15, and a control means 29 for controlling the control valve 27 and the exhaust brake 25 according to an instruction injection amount signal 35 from the engine control device 34, a gas temperature 30a with the gas thermometer 30, and a catalyst temperature 33a obtained with the catalyst temperature detection means 31 in such a manner that the low temperature exhaust gas 9 which degrades the activity of the oxidation catalyst 15 is not guided to the exhaust emission control device 14. <P>COPYRIGHT: (C)2010,JPO&INPIT |
