| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control device of an internal combustion engine capable of providing a high NOx purification rate with less energy at rich spikes. <P>SOLUTION: This exhaust emission control device comprises an NOx storage catalyst installed in the exhaust passage of the internal combustion engine, having a plurality of flow passages arranged parallel with each other therein, combining the exhaust flows in these flow passages with each other in a series direction, and storing NOx in exhaust gases in lean operation and releasing and reducing NOx stored in rich operation, a selector valve disposed in the NOx storage catalyst and capable of reversing the flow direction of the exhaust gases in the flow passages combined with each other in the series direction, a temperature determination means S303 to S305 comparing the temperature at the inlet side with the temperature at the outlet side based on information from a temperature detection means disposed in the NOx storage catalyst, and a selector valve control means (S306, S307) maintaining the direction of a current exhaust flow when the temperature at the inlet side is lower than the temperature at the outlet side in rich operation and operating the selector valve so that direction of the exhaust gases can be reversed when the temperature at the inlet side is higher than the temperature at the outlet side. <P>COPYRIGHT: (C)2007,JPO&INPIT |
