ANTIFREEZING UREA SOLUTION FOR UREA SCR SYSTEM AND UREA SCR SYSTEM USING THE SAME

摘要

An antifreezing urea solution is disclosed which is supplied from a urea solution tank to an adding value to be injected to an SCR catalyst disposed in an exhaust passage of an internal combustion engine. The antifreezing urea solution includes a mixed solution composed of a concentrated urea solution with a urea concentration of 30 wt % or more, and an organic solvent of an alcohol family with 1 to 7 carbon atoms having a hydrophilic group, wherein the urea solution and the organic solvent of the alcohol family are mixed at a mixture ratio of 7:1 respectively (in a volume ratio) or more, providing a freezing point of −30° C. or less.