Diesel exhaust fluid with additive

Abstract

A diesel exhaust fluid (DEF) for reducing nitrogen oxides in diesel exhaust streams while also reducing the deposition of urea and/or urea decomposition compounds in diesel exhaust systems of engines that use DEF and require selective catalytic reduction. The DEF has about 15 wt. % to about 40 wt % urea; substantially purified water; and a compound additive that generates water in the diesel exhaust streams at temperatures greater than 100° C., interferes with competing reactions that would otherwise prevent decomposition of urea or produce undesired decomposition deposit compounds including biuret, cyanuric acid, ammelide, ammeline, and melamine, or both generates water and interferes with the competing reactions. The compound additive is preferably a sugar, acetic acid, or ammonium acetate. Also disclosed are a related method of using the DEF in a diesel exhaust system and a system including the DEF as one component.