| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control device capable of supplying a NOx catalyst with appropriate quantity of ammonia by adding urea water in exhaust gas without causing clogging. <P>SOLUTION: This device is provided with urea water supply means 38, 40, 42 supplying the NOx catalyst 30 with ammonia as reducer by adding urea water to exhaust gas of the engine, a urea water supply quantity adjusting means 54 adjusting quantity of urea water added to exhaust gas from the urea water supply means 38, 40, 42, and a control means 56 keeping supply quantity of urea water from the urea water supply means 38, 40, 42 par unit time at a lower limit value or less and controlling the urea water supply quantity adjusting means 54 to intermittently add urea water to exhaust gas with corresponding to target supply quantity when target supply quantity of urea water necessary for reduction conversion of NOx by the NOx catalyst 30 is less than the lower limit value. <P>COPYRIGHT: (C)2007,JPO&INPIT |
