| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control device which decreases temperature differences between respective sections in raising the temperature of NOx occlusion agent 12, thus keeping the temperature of the entire occlusion agent not less than sulfur emission temperature. <P>SOLUTION: A reducing agent is added with the flow rate of exhaust gas flowing through the NOx occlusion agent 12 taken as a predetermined flow rate so that the temperature of the entire NOx occlusion agent 12 is not less than the sulfur emission temperature in discharging the sulfur content from the NOx occlusion agent 12. The device 20 decreases a temperature difference between the temperatures on the upstream and downstream sides of the NOx occlusion agent 12 by increasing the flow rate to exhaust gas up to a predetermined another flow rate in such a state where the flow rate of the exhaust gas flowing through the NOx occlusion agent 12 is made to flow unidirectionally without reversal of the passing flow. As a result, the difference in the temperatures on the upstream and downstream sides of the NOx occlusion agent 12 decreases, and the entire NOx occlusion agent 12 can be kept not less than the sulfur emission temperature at the same time, thus attaining sufficient regeneration of sulfur poisoning over the NOx occlusion agent 12. <P>COPYRIGHT: (C)2004,JPO |
