| 摘要 |
<P>PROBLEM TO BE SOLVED: To suitably control the amount of addition of a reducing agent by estimating the amount of adsorption of the reducing agent for a NOx reduction catalyst. <P>SOLUTION: A control method of an exhaust purifier is that the NOx reduction catalyst 10 is provided at some midpoint in an exhaust pipe 9, and that urea water 17 (the reducing agent) is added to the upstream side of the NOx reduction catalyst 10 by a means 18 of adding the urea water (a means of adding the reducing agent), thus NOx is reduced and purified. Then the amount of generation of NOx is estimated, and the amount of addition of the urea water 17 appropriate to the estimated value is determined. On the other hand, the progression of the concentration of NOx on the outlet side of the NOx reduction catalyst 10 after the addition of the urea water 17 is stopped is monitored. Then the amount of adsorption of the urea water 17 for the NOx reduction catalyst 10 is estimated in response to the degree of its variations. A correction coefficient that is appropriate to the amount of adsorption is determined, and the amount of addition of the urea water 17 is corrected by the correction coefficient. Then the corrected amount of addition of the urea water 17 is made an indicating value for addition for the means 18 of adding the urea water. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
