Diesel Exhaust Fluid (DEF) is a reactant that’s key to the SCR process. It’s a nontoxic, aqueous solution of 32.5% urea and 67.5% water. Urea is a compound of nitrogen that turns to ammonia when heated. It is used in a variety of industries, perhaps most commonly as a fertilizer in agriculture.
DEF consumption is related to fuel consumption. A highway truck may travel 225-300 miles or more on one gallon of DEF. If a driver runs out of DEF a gauge much like a fuel gauge will indicate the level of DEF in the tank. A DEF low-level warning will activate when DEF is low. If a driver runs out of DEF completely, vehicle power will be reduced to derate mode. When the DEF tank is refilled, the engine will resume normal power.
How does outside temperature affect DEF? DEF will begin to freeze at 12 degrees F. The SCR system provides heating for the DEF tank and supply lines. If the DEF freezes when the vehicle is not operating, start-up and normal operation of the vehicle will not be affected. The SCR heating system will heat the DEF to liquid form and vehicle operation can continue normally. When frozen, DEF expands by about 7%. DEF tanks are designed to accommodate this expansion.
Store DEF in a cool, dry and ventilated area, away from direct sunlight. Recommended storage temperature is up to 77 degrees F, though brief exposure to higher temperatures will not be a problem. DEF’s shelf life is largely a factor of storage temperature. DEF degrades over time depending on temperature and exposure to sunlight. If stored at recommended temperatures (not exceeding 77 degrees F) shelf life will be two years.
Naturally, the DEF Volvo's SCR system uses is safe to handle and safe for the environment. DEF is nontoxic, nonhazardous and nonflammable. It is non-polluting and meets strict international standards for purity and composition. DEF poses no serious risk to drivers or equipment when handled properly. DEF is corrosive to certain sensitive metals. DEF tanks and dispensing equipment will be made of an appropriate, heavy-duty plastic.
Volvo vehicles with an SCR system require no change to service and maintenance intervals. A small DEF filter on the pump intake can be changed in minutes. No catalyst maintenance is required.
DEF is available in 2.5-gallon containers, 55-gallon drums, 275 gallon IBC and in bulk storage for fleet locations, truck stops and dealerships. All major truck stops, dealers and distributors carry DEF -- it's available everywhere drivers are.