AdBlue is the registered trademark for AUS32 (Aqueous Urea Solution 32.5%) and is used in a process called selective catalytic reduction (SCR) to reduce emissions of oxides of nitrogen from the exhaust of diesel engined motor vehicles. As the name AUS32 would suggest, it is a 32.5% solution of high-purity urea in demineralised water that is clear, non-toxic and is safe to handle. However, it can be corrosive for some metals, and must be stored and transported using the correct materials. The AdBlue trademark is currently held by the German Association of the Automobile Industry (VDA), who ensure quality standards are maintained in accordance with ISO 22241 specifications.
AdBlue is carried onboard SCR-equipped vehicles in specially designed tanks, and is dosed into the SCR system at a rate equivalent to 3–5% of diesel consumption. This low dosing rate ensures long refill periods and minimises the tank's impact on chassis space. On-highway SCR systems are currently in use throughout Europe, in Japan, Australia, Hong Kong, Taiwan, Korea, New Zealand and Singapore. The United States Environmental Protection Agency's (US EPA) 2010 legislation will limit NOx to levels that will require North American trucks to be equipped with SCR post-2010. The current generic name in North America for AUS32 is diesel exhaust fluid (DEF). Some trucking industry OEMs have already developed branded SCR solutions, such as Daimler's BlueTec.
All European truck manufacturers currently offer SCR equipped models, and the future Euro6 emission standard is set to reinforce the demand for this technology. SCR systems are sensitive to potential chemical impurities in the urea solution, therefore, it is essential to maintain high standards of AdBlue quality according to the ISO 22241 standard.
The use of SCR technology in Europe made it necessary to develop an AdBlue supply infrastructure. AdBlue is available from thousands of service stations, this locator finder
is updated monthly with new Retail sites selling AdBlue. It can also be purchased in canisters of 5 or 10 litres (1.1 or 2.2 imp gal; 1.3 or 2.6 USgal) at service stations. Larger quantities of AdBlue can be delivered in, for example, 208 litres (46 imp gal; 55 US gal) drums, 1,000 litres (220 imp gal; 260 US gal) Intermediate Bulk Containers (IBCs), and bulk.
From http://en.wikipedia.org/
