| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control system of an internal combustion engine, capable of accurately estimating the amount of reducing agents captured in a selected reduction catalyst by discriminating between ammonium and urea water. <P>SOLUTION: The exhaust emission control system includes an NOx sensor and a unit conversion unit for acquiring a feed NOx amount QNOX equivalent to an exhaust NOx amount flowing into a first selected reduction catalyst, a first conversion rate calculation unit 511 for calculating a first NH<SB POS="POST">3</SB>conversion rate RNU1 equivalent to the rate of urea water converted into NH<SB POS="POST">3</SB>in urea water supplied on the basis of a first equivalent rate α<SB POS="POST">1ST</SB>which is a ratio of a supplied urea water amount QUREA to the feed NOx amount QNOX, a first NH<SB POS="POST">3</SB>supplied amount estimation unit 512 for estimating a first NH<SB POS="POST">3</SB>supply amount NH3<SB POS="POST">1ST</SB>which is a NH<SB POS="POST">3</SB>supply amount to the first selected reduction catalyst on the basis of the first NH<SB POS="POST">3</SB>conversion rate RNU1, and a first storage amount estimation unit for estimating a storage amount equivalent to NH<SB POS="POST">3</SB>captured in the first selected reduction catalyst. <P>COPYRIGHT: (C)2012,JPO&INPIT |
