Diesel exhaust fluid
AdBlue (ISO 22241/DIN 70070/AUS32 ) is the brand name for a urea-based liquid that is used in the exhaust gas treatment of automobile diesel engines for the reduction of nitrogen oxides. The application takes place in the SCR ( selective catalytic reduction, SCR); there is reduced by selective catalytic reduction of the emission of nitrogen oxides (NOx), about 90% ( in the steady-state operation ). The trademark AdBlue lie at the Association of the Automotive Industry ( VDA). In North America, the name of Diesel Exhaust Fluid (DEF ) is used.
The liquid is a water-clear, synthetically produced 32.5 percent solution of high-purity urea in demineralised water.
Application
The aqueous urea solution is a chemical for cleaning exhaust gas, which is far in commercial vehicles ( trucks and buses in particular ) were used. AdBlue has been used since 2007 in the USA in the PKW area in vehicles with diesel engine and SCR catalysts (BMW and Mercedes ). In the Mazda CX -7 ( MZR 2.2 diesel ) and now also Volkswagen AdBlue is already being used in some BlueMotion models ( eg VW Passat, VW Sharan II). The same is true for the identical SEAT Alhambra, whose diesel versions are supplied with AdBlue engines since autumn 2010. In the Audi A8, both diesel engines available have a SCR catalyst and already meet the Euro 6 emissions standard. In other models this is available as an option (Audi Q7, Audi A4, Audi Q5). Since October 2010, the Mercedes -Benz S 350 Bluetec is equipped as standard with an AdBlue exhaust treatment. As of 2013, Opel also uses the auxiliary for its new diesel engine generation. Urea solution has been used for many years for the reduction of nitrogen oxides in flue gas denitrification in stationary engines and power plants.
AdBlue is produced in Northern Europe primarily by the company BASF, AMI, nitrogen SKW Piesteritz, Hoyer Group and Yara.
The world's first AdBlue filling station opened the OMV in March 2003 in the Bavarian town Dingolfing. Meanwhile, AdBlue by a number of other service station operators ( Aral, Raiffeisen - gas stations, Westfalen AG, Total, AGIP, Tank & Rast, Shell, AVIA, Hoyer KG ) available either on fuel dispensers or as a canister. For the use of AdBlue, an additional tank is attached to the vehicle, the consumption of urea-water solution is about 4-6 % of the normal fuel consumption and comply with heavy truck about 1.4 liters for a distance of 100 km.
The urea technology as part of the exhaust gas purification is currently being developed, since since October 1, 2006 shall meet the Euro 4 standard for exhaust and since October 1, 2009, the Euro - 5 emissions standard stricter again. By 2012, the European urea demand for commercial vehicles will be already at about 3.5 million tonnes.
As the first Japanese automobile manufacturer Mazda presented in September 2009 at the International Motor Show ( IAA) in Frankfurt a vehicle with a diesel engine and SCR exhaust treatment. The system comes in the revised version of the Mazda CX -7 is used, which is offered on the European market since October 2009 and the Euro - 5 standard met.
Operation
The SCR process uses ammonia which is recovered from the urea on board the vehicle. The urea solution tank is disposed in a separate, for example, by means of metering or metered injector is injected into the exhaust gas stream and provides in the SCR catalyst for a chemical reaction. Here, only the nitrogen oxides into nitrogen and water vapor are converted. The ratio of urea solution to diesel fuel is about 1:20 to 1:30.
Pros and cons of using AdBlue
Benefits
- Conditionally suitable for the use of biodiesel
- Fuel savings of up to about 8 % by saving the exhaust gas recirculation
- Allows compliance with the Euro 4 emission standard, Euro 5 standards, Euro - 6 standard ( PKW) and BIN 5 standard ( USA, PKW)
- Available at all relevant truck filling stations in Europe at least as canister goods
- No impact on service and oil change intervals
- Water hazard class 1 (weak)
Disadvantages
- Additional space required for the container
- Additional weight of the plant and its liquid
- Freezing at -11 ° C, decomposition at about 60 ° C.
- Additional costs due to additional AdBlue refueling
- Disturbance of the system by crystalline urea
Practice
Several European countries reward the early completion of Euro 4 and 5 with perks such as lower road user charges ( in Germany, for example, a discount of 2 cents per kilometer for the motorway toll ). The toll advantage of 0.02 € per kilometer offered in Germany in the meantime only € 5, since October 1, 2006 Euro 4 was required by law; since 1 October 2009 are Euro 4 and 5 again ranked equally in the toll table.
Hazards and health
From AdBlue no special hazard is due within the meaning of European chemicals legislation. Also, according to the Transportation Law, AdBlue is non-hazardous. Skin contact should be avoided; wash off any residues with water.