| 摘要 |
PROBLEM TO BE SOLVED: To efficiently control the emission of PM (particulate substances) and NOx contained in exhaust gas, in spite of the operating conditions, by only arranging a DPF(a diesel particulate filter) with catalyst and a HC selective reduction NOx(nitrogen oxide) catalyst. SOLUTION: The DPF with catalyst 20 and the HC selective reduction NOx catalyst 30 are arranged, in sequence on the upstream of an exhaust path 12 for a diesel engine 10. When the HC selective reduction NOx catalyst 30 is utilized for coping with increase in NOx amount due to the operated condition of the diesel engine 10, the amount of fuel containing a HC component as a reducer, calculated by an ECU 40, is partially injected from an injector 16 so as not to contribute to increase in the output of the diesel engine 10. The amount of HC, passing through the DPF with catalyst 20, is increased by controlling the opening/closing of a throttle valve for correcting the flow rate of exhaust gas made to flow into the DPF with catalyst 20. Thus, the DPF with catalyst 20 and the HC selective reduction NOx catalyst 30 are used to efficiently control the emission of the PM and the NOx, respectively. |
