| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an SCR (Selective Catalytic Reduction) system in which a NOx cleaning rate can be improved even for a vehicle etc. having small weight. <P>SOLUTION: The system includes: a selective reduction catalyst device 103 provided to the exhaust pipe 102 of an engine E; an exhaust temperature sensor 109 provided to the exhaust pipe 102 of an upper stream side of the selective reduction catalyst device 103 and detecting the temperature at the inlet of a selective reduction catalyst, which is the exhaust gas temperature at the inlet of the selective reduction catalyst device 103; a urea water injection control part 127 in which when the temperature at the inlet of the selective reduction catalyst is previously set urea water injection start temperature or higher, the urea water is injected from a dosing valve 104 at an injection amount corresponding to NOx amount discharged from the engine E; and a timing retard control part 1 delaying fuel injection timing in the engine E by a portion of a correction amount corresponding to the temperature at the inlet of the selective reduction catalyst when the temperature at the inlet of the selective reduction catalyst is less than urea water injection start temperature. <P>COPYRIGHT: (C)2012,JPO&INPIT |
