UREA WATER SUPPLY DEVICE FOR INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To provide an urea water supply device for an internal combustion engine that can suppress corrosion of an urea addition valve caused by urea water.SOLUTION: An urea water supply device 200 for an internal combustion engine 1 includes: a tank 210 for storing urea water; an urea addition valve 230 provided in an exhaust passage 28 to add urea water to exhaust gas; an urea water passage 240 for supplying the urea water in the tank 210 to the urea addition valve 230; and a pump 220 provided in the urea water passage 240. When pressure of the urea water supplied to the urea addition valve 230 is a predetermined pressure or lower and the amount of urea water in the tank 210 is a predetermined threshold value or less, a control device 80 determines that the addition amount of urea water required for cooling the urea addition valve 230 cannot be supplied from the tank 210 to the urea addition valve 230, and executes sucking back control for sucking back the urea water in the urea addition valve 230 to the tank 210.SELECTED DRAWING: Figure 1