Exhaust emission control device

摘要

The disclosed exhaust purification device is provided with: a selective reduction catalyst which causes the NOx contained in exhaust gas to react with ammonia; a urea solution addition means which adds a urea solution to the exhaust gas further upstream from the selective reduction catalyst; and a cylindrical mixing pipe which connects the space from the urea solution addition means to the selective reduction catalyst. A mixer structure is formed by forming an opening in a position in the circumferential direction of the end section of the mixing pipe on the input side, and disposing guide fins so that the exhaust gas is introduced to the opening from the tangential direction of the end section on the input side. The urea solution addition means is disposed in a central position on the end section on the input side and facing the end section on the output side in such a way that the urea solution can be added to the exhaust gas swirl flow by the mixer structure. The opening is formed so as to follow the flow of the swirl flow.