摘要 |
<P>PROBLEM TO BE SOLVED: To suppress precipitation of urea or the like after pump drive is stopped, and to suitably add and supply a reducing agent aqueous solution, by extension. <P>SOLUTION: A urea water addition valve 15 is connected to a urea water tank 21 via a urea water supply pipe 22. A urea water pump 23 is disposed at the urea water supply pipe 22 such that the urea water pump 23 is not immersed in urea water in the urea water tank 21. The urea water supply pipe 22 is provided with: a filter device 25 for storing urea water fed by the urea water pump 23; and a first check valve 24 for supplying the urea water stored in the filter device 25 by prescribed amounts to the urea water pump 23 in a state where a drive of the urea water pump 23 is stopped. <P>COPYRIGHT: (C)2010,JPO&INPIT |