Home :: What is AdBlue?

What is AdBlue?

AdBlue® is a registered trademark of the Verband der Automobilindustrie e.V. (VDA). (www.vda.de) for AUS32 (Aqueous Urea Solution 32%), it is also often referred to as ERS (Emission Reduction Solution) or DEF (Diesel Exhaust Fluid).

AdBlue is a high purity solution used by many modern diesel engines in conjunction with a Selective Catalytic Reducer (SCR) which significantly reduces harmful nitrogen oxide (NOx) emissions from the vehicle’s exhaust.

AdBlue never comes into contact with the fuel, it is a common misconception that it is an additive.

A modern diesel engine operating with AdBlue produces less harmful emissions than its petrol equivalent.

How does it work?

AdBlue is carried on board the vehicle in its own separate storage tank. It is injected into the exhaust gases as a post combustion process through an SCR where the aqueous urea vaporises and decomposes to form ammonia and carbon dioxide, these gases then break the harmful nitrogen oxide (NOx) emissions down into nitrogen and water.

Regulatory Influence

Requirements for the reduction of all harmful emissions including NOx produced by diesel engines is defined within European Union directives and a series of staggered European emission standards are in place to continually improve air quality by reducing harmful emissions. Initial targets for emission reduction were aimed at Public Transport and the Commercial Sector (HGV’s) but recent legislation now influences smaller vehicles with diesel engines including cars and vans both within the commercial and public sectors.

Recent European emission standards for Diesel engine passenger cars (Category M*), g/km

Euro 5b Sept 2011 0.500 - - 0.180 0.230 0.005 6 x 1011
Euro 6 Sept 2014 0.500 - - 0.080 0.170 0.005 6 x 1011
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