| 摘要 |
<p>There is provided an exhaust purifying device for an internal combustion engine in which NOx can be appropriately purified in a selective catalytic reduction and occurrence of an ammonia slip due to a temperature rise of the selective catalytic reduction can be restricted. In the exhaust purifying device for the internal combustion engine provided with the selective catalytic reduction (70) provided in an exhaust passage (10) of the internal combustion engine (1) to selectively reduce nitrogen oxides contained in an exhaust gas (EG) and a urea water adding valve (60) for supplying ammonia as a reducing agent, an absorption excess amount of the ammonia in the selective catalytic reduction (70) is calculated based upon a maximum absorption amount of the ammonia capable of being absorbed by the selective catalytic reduction (70) and changing with a temperature and an actual absorption amount of the ammonia actually absorbed in the selective catalytic reduction (70), and at least one of an operating condition in the internal combustion engine (1) and the urea adding valve (60) is controlled in such a manner that the absorption excess amount calculated is secured at a predetermined value or greater.</p> |
