| 摘要 |
Provided is an SCR thawing control system that can distinguish between a thawing failure and a malfunction and can prevent a malfunction of an SM pump. When urea water is frozen in any one of a urea tank 105 for storing urea water, liquid feed, pump and recovery lines 116, 117, 118 between the urea tank 105 and a dosing valve 104 for injecting urea water on an upstream side of an SCR device 103, and a supply module 106 connected to the liquid feed, pump and recovery lines 116, 117, 118, an SCR thawing control system 127 thaws the frozen urea water by engine cooling water and operates an SM pump 112 of the supply module 106 after the thawing to inject the thawed urea water from the dosing valve 104. The thawing control system 127 includes a thawing control unit 128 that detects a pressure inside the supply module 106 when the SM pump 112 is operated, and stops the operation of the SM pump 112 and continues thawing of the urea water when the pressure is less than a predetermined value. |
