| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control system for an internal combustion engine that prevents a captured reducing agent from being discharged to the downstream side even when a drastic temperature change occurs in a selective reduction catalyst. <P>SOLUTION: The exhaust emission control system includes: a first selective reduction catalyst that purifies exhaust under the presence of ammonia; a urea injection device that injects urea water to the upstream side of the first selective reduction catalyst; a catalyst-temperature prediction part 53 that predicts a predicted temperature equivalent to a temperature of the first selective reduction catalyst after the prediction time TPRE from the current time; a storage amount estimating part 56 that estimates a storage amount of the selective reduction catalyst; a target storage amount calculating part 55 that calculates a target storage amount on the basis of the estimated predicted temperature T<SB POS="POST">CAT_PRE</SB>; and a storage injection amount calculating part 52 that calculates a storage injection amount G<SB POS="POST">UREA_ST</SB>, being a part of a urea injection amount G<SB POS="POST">UREA</SB>injected by the urea injection device, so that the estimated storage amount ST<SB POS="POST">UREA</SB>may become the target storage amount ST<SB POS="POST">UREA_TRGT</SB>. <P>COPYRIGHT: (C)2012,JPO&INPIT |
