| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control device and a method of recovering from poisoning, which can efficiently reduce and desorbe the second exhaust gas from an exhaust catalyst by maintaining an oxygen occulusion amount lower in the exhaust catalyst, when reducing a second exhaust gas component. <P>SOLUTION: An exhaust emission control device 10 includes an NSR catalyst 24 for removing NOx within exhaust gas of a diesel engine 12 by occulusion and reduction, a bypass pipe 26 for bypassing the NSR catalyst 24, a three-way valve 28 for switching open/close states of the bypass pipe 26 and an NSR catalyst converter 20, and an ECU 30 for controlling the three-way valve 28. When SOx is removed from the NSR catalyst 24 by reduction, the ECU 30 closes the bypass pipe 26 by the three-way valve 28 under a low air fuel ratio operation and opens the bypass pipe 26 by the three-way valve 28 under a high air fuel ratio operation, while repeating the low and high air fuel ratio operations in the diesel engine 12. <P>COPYRIGHT: (C)2011,JPO&INPIT |
