| 摘要 |
PROBLEM TO BE SOLVED: To provide a control device for an exhaust emission control system that reduces emissions of ammonia derived from urea water to make consumption of the urea water appropriate.SOLUTION: An injector control section 32 controls the amount of urea water injected from an injector 20 by using a temperature of a reduction catalyst 17 indirectly or directly detected on the basis of a temperature of exhaust gas detected by a temperature sensor 33 and a concentration of ammonia included in exhaust gas and detected by a concentration sensor 34. The amount of ammonia that can be held by the reduction catalyst 17 varies depending on the temperature. The injector control section 32 controls the injector 20 by using the temperature of the reduction catalyst 17 and the ammonia concentration in the exhaust gas. Thus, the amount of urea water added to the exhaust gas from the injector 20 is controlled while not only the amount of the ammonia passed through the reduction catalyst 17 but also the temperature of the reduction catalyst 17 are considered.SELECTED DRAWING: Figure 1 |
