| 摘要 |
PROBLEM TO BE SOLVED: To enhance a NOx purification rate and prevent slipping of ammonia from a tail pipe. SOLUTION: In the exhaust emission control apparatus for a diesel engine, an apparatus 4 for reducing particulate matters is disposed at a front stage of an exhaust pipe 2 installed to the diesel engine 1 and a NOx catalyst 5 is disposed at a rear stage of the exhaust pipe. A rate of NO to NO2 is calculated based on an outlet temperature of the apparatus 4 for reducing particulate matters, and an amount of urea supplied to the NOx catalyst 5 is controlled based on the value of the NO/NO2 ratio. |
