AdBlue® is a solution of urea in water, which is injected into the diesel exhaust system of vehicles with Selective Catalytic Reduction (SCR) technology. A chemical reaction occurs at the high temperatures where up to 90% of the nitrogen oxides (NOx) produced by the vehicle are converted into more environmentally friendly components: nitrogen and water vapour.
AdBlue is a diesel exhaust fluid used in vehicles with Selective Catalytic Reduction (SCR) technology to reduce harmful gases being released into the atmosphere. AdBlue is a 32,5 % solution of high-purity, synthetically manufactured urea in de-mineralized water. It is a safe-to-use fluid.
Vehicles with SCR technology have a separate tank filled with AdBlue. This is then injected into the exhaust pipe, in front of the SCR catalyst, downstream of the engine.
Heated in the exhaust, it decomposes into ammonia and CO₂. When the NOx from the engine exhaust reacts inside the catalyst with the ammonia, the harmful NOx molecules in the exhaust are converted to harmless nitrogen and water, which are released from the tail pipe as steam.