How does SCR technology work?
SCR technology (selective catalytic reduction) uses AdBlue to break down pollutants. AdBlue, a registered trademark of the German Association of the Automotive Industry, consists of 32.5% urea and 67.5% demineralised water. The mixture is odourless and non-toxic, and it reduces nitrogen oxide (NOx) emissions from diesel engines by up to 90%. The urea is injected directly into the exhaust gas where it releases ammonia. The ammonia reacts with the nitrogen oxide in the SCR catalytic converter to produce nitrogen and water vapour. AdBlue is completely harmless to the engine.
The engine control system ensures that the optimum amount of AdBlue is injected into the exhaust tract. This is about four to six percent of diesel consumption. Converted to a HGV that consumes an average of 33.5 litres of diesel/100 km, this is about 1.3 to 2 litres of AdBlue per 100 kilometre.