AdBlue
Encyclopedia
Diesel Exhaust Fluid is an aqueous urea
solution used in Selective Catalytic Reduction
(SCR) to lower NOx
concentration in the exhaust emissions from diesel engine
s. The solution may also be referred to 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. Initially the specification was described in DIN
70070. 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.
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.
Urea
Urea or carbamide is an organic compound with the chemical formula CO2. The molecule has two —NH2 groups joined by a carbonyl functional group....
solution used in Selective Catalytic Reduction
Selective catalytic reduction
Selective catalytic reduction is a means of converting nitrogen oxides, also referred to as with the aid of a catalyst into diatomic nitrogen , , and water, . A gaseous reductant, typically anhydrous ammonia, aqueous ammonia or urea, is added to a stream of flue or exhaust gas and is absorbed...
(SCR) to lower NOx
NOx
NOx is a generic term for the mono-nitrogen oxides NO and NO2 . They are produced from the reaction of nitrogen and oxygen gases in the air during combustion, especially at high temperatures...
concentration in the exhaust emissions from diesel engine
Diesel engine
A diesel engine is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber...
s. The solution may also be referred to as AUS32, shorthand for Aqueous Urea Solution, 32.5%, or as AdBlue, a trademark held by the German Association of the Automobile Industry (VDA
VDA
The Verband der Automobilindustrie e. V., short VDA, is a German interest group of the German automobile industry, both automobile manufactures and automobile component suppliers. The group is located in Berlin, Germany...
), who ensure quality standards are maintained in accord with ISO 22241 specifications. Initially the specification was described in DIN
Din
DIN or Din or din can have several meanings:* A din is a loud noise.* Dīn, an Arabic term meaning "religion" or "way of life".* Din is one of the ten aspects of the Ein Sof in Kabbalah ....
70070. 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.
SCR systems are sensitive to potential chemical impurities in the urea solution, therefore the solvent
Solvent
A solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature...
is demineralized water. The solution is clear, non-toxic and safe to handle. However, it can corrode
Corrosion
Corrosion is the disintegration of an engineered material into its constituent atoms due to chemical reactions with its surroundings. In the most common use of the word, this means electrochemical oxidation of metals in reaction with an oxidant such as oxygen...
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
Electronic control unit
In automotive electronics, electronic control unit is a generic term for any embedded system that controls one or more of the electrical systems or subsystems in a motor vehicle....
adjusts the addition of fluid in accord with such parameters as engine operating temperature
Operating temperature
An operating temperature is the temperature at which an electrical or mechanical device operates. The device will operate effectively within a specified temperature range which varies based on the device function and application context, and ranges from the minimum operating temperature to the...
and speed.
External links
- Contamination Advice and Support
- Diesel Exhaust Fluid search engine for North America
- Guidelines and technical information on handling AdBlue correctly
- 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