| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control device which always supplies a required quantity of hydrogen for purifying NOx to the NOx purifying catalyst on the upstream side of an exhaust route independently of a fluctuation of flow quantity and flowing speed of the exhaust gas, and efficiently purifies the nitrogen oxide even in a low temperature range. <P>SOLUTION: This exhaust emission control device is mainly composed of the hydrogen catalyst 7, the NOx purifying catalyst 8 and a catalyst control unit 11. The catalyst control unit 11 controls the device so as to increase one or both of depth and time for making the exhaust rich more, as the exhaust gas flow quantity is reduced more. <P>COPYRIGHT: (C)2004,JPO |
