| 摘要 |
PROBLEM TO BE SOLVED: To reduce costs without deteriorating emission control performance of an exhaust gas.SOLUTION: An exhaust gas in an exhaust pipe 14 on a downstream side of an SCR catalyst 24 is brought into contact with water in a water storage tank 29, ammonia discharged upon NOx purification is absorbed and neutralized to be rendered harmless, and the gas is returned to an exhaust passage from a return passage. As a result, ammonia is rendered harmless without using an ammonia oxidation catalyst made with an expensive noble metal. |
