Diesel exhaust fluid

A jug of diesel exhaust fluid on a Canadian Tire store shelf

Diesel Exhaust Fluid (DEF) is an aqueous urea solution used in Selective Catalytic Reduction (SCR) to lower NO_x concentration in the exhaust emissions from diesel engines. The solution may also be referred to^{[by whom?]} as AUS32, shorthand for Aqueous Urea Solution, 32.5%, or as AdBlue, a trademark held by the German Association of the Automobile Industry (VDA), who ensure quality standards are maintained in accord with ISO 22241 specifications.^{[citation needed]} Initially the specification was described in DIN 70070.^[1] In 2006 the worldwide ISO 22241 standard was introduced, which also stipulates analytical test protocols to verify adherence to specifications, as well as requirements for storage, transport and handling of the fluid.^{[citation needed]}

SCR systems are sensitive to potential chemical impurities in the urea solution, therefore the solvent is demineralized water. The solution is clear, non-toxic and safe to handle. However, it can corrode some metals and so must be stored and transported in vessels made of materials not so affected. DEF is stored in a tank onboard the vehicle, and injected into the exhaust stream by a metering system at a rate of 3–5% of diesel consumption volume. This low dosing rate ensures long fluid refill intervals and minimises the tank's obtrusion into vehicle packaging space. An Electronic control unit adjusts the addition of fluid in accord with such parameters as engine operating temperature and speed.

References

1. ^ Trautwein, Wolf-Peter (2003) (PDF). AdBlue as a Reducing Agent for the Decrease of NO_x Emissions from Diesel Engines of Commercial Vehicles (Technical report). DGMK Deutsche Wissenschaftliche Gesellschaft für Erdöl, Erdgas und Kohle e.V.. 616-1. http://dgmk.de/downstream/publikationen/im_netz/report_616-1_e.pdf. 

External links

• Contamination Advice and Support
• Diesel Exhaust Fluid search engine for North America
• Guidelines and technical information on handling AdBlue correctly
• MSDS for AdBlue UK version
• MSDS for Diesel Exhaust Fluid (DEF)
• Component limits for AdBlue as outlined in DIN 70070
• FactsAboutSCR.com North American SCR Stakeholders Group
• United States EPA DEF Purchase Location Finder
• Independent AdBlue market analysis
• AdBlue Industry News and Headlines
• International 2010 emissions for the MaxxForce engine
• Diesel Exhaust Fluid Quick Facts & Information