UREA WATER PIPING CLOGGING DETECTION DEVICE FOR UREA SCR

摘要

PROBLEM TO BE SOLVED: To provide a urea water piping clogging detection device for urea SCR which can adequately detect whether or not urea water is clogged in piping reaching a dosing valve which sprays urea water.SOLUTION: A urea water piping clogging detection device for urea SCR comprises: a urea water sensor 22 which detects a urea water temperature in a urea water tank 15 when detecting the clogging of a piping part which reaches a dosing valve 12 from a supply pump 18; a pressure sensor 27 which detects the pressure of a pressure-sending line 20; an exhaust temperature sensor 26 arranged at an exhaust pipe 10 at the upstream side of an SCR device 11; and clogging determination means 33 which performs empting control for returning urea water in the piping part to the urea water tank 15 when a detection value at the exhaust temperature sensor 26 is not higher than a set temperature and a detection value at the urea water sensor is not lower than a freeze temperature after performing startup control for boosting the piping part by driving the supply pump 18 when a key switch is turned on, and detects the clogging of the piping part from a detection value of the pressure sensor at the empting control.