| 摘要 |
PROBLEM TO BE SOLVED: To optimize the amount of reductant to be added to a selective reduction type NOx catalyst.SOLUTION: An exhaust emission control device for an internal combustion engine estimates an ammonia adsorption amount on the basis of one or more predetermined parameters relating to the ammonia adsorption amount of the selective reduction type NOx catalyst, estimates a specified ammonia adsorption amount as an estimated value for the ammonia adsorption amount defined by at least one of a maximum value and a minimum value of the estimated value for the ammonia adsorption amount on the basis of errors of the predetermined parameters, and controls the precursor of ammonia or the ammonia to be added by an addition valve so that, when the specified ammonia adsorption amount deviates from the target range of the ammonia adsorption amount, it returns to the target range.SELECTED DRAWING: Figure 9 |
