| 摘要 |
PROBLEM TO BE SOLVED: To provide an SCR system capable of preventing an ammonia slip during regeneration of a DPF. SOLUTION: The SCR system includes: a calculation storage amount computing part 127 calculating a calculation storage amount which is the storage amount of ammonia occluded in an SCR device 103, by using the SCR inlet temperature detected by an exhaust temperature sensor 109; an efficiency map 128 in which emission control efficiency of the SCR device 103 is given for every SCR inlet temperature, calculation storage amount, exhaust gas flow rate and outside air temperature; an emission control efficiency computing part 129 obtaining the emission control efficiency of the SCR device 103 while referring to the efficiency map 128 by an SCR inlet temperature, calculation storage amount, exhaust gas flow rate and outside air temperature; and an urea water injection control part 130 controlling an urea water injection amount according to the emission control efficiency obtained by the emission control efficiency computing part 129 and to a NOx concentration in exhaust gas. COPYRIGHT: (C)2012,JPO&INPIT |
