AdBlue® is a biodegradable, water-based additive that’s been developed specifically to make your engine more environmentally friendly. The solution is stored separately from your fuel tank and is pumped in small quantities into the exhaust when the engine is running – breaking down nitrogen oxide gas into water vapour and nitrogen gas. 

A brand name of diesel exhaust fluid (DEF) that is trademarked and overseen by the German Association of the Automotive Industry, a trade group that represents both German car manufacturers and automo [..]

The SCR catalytic converter (Selective Catalytic Reduction) converts the exhaust constituent nitrogen oxide (NOx) into nitrogen and water without producing undesirable by-products. This conversion takes place using a synthetically produced aqueous urea solution, e.g. AdBlue, which is carried in an auxiliary tank. The substance, containing 32.5 perc [..]

A solution added to diesel cars in order to reduce the amount of harmful gases coming out of the exhaust.