AdBlue® is a soluble colourless solution that looks like water or windscreen washer fluid. It is composed of 67.5% distilled water and 32.5% high grade urea, such as that used to manufacture plastics, cosmetic products or fertilisers. Urea used as a synthetic product is typically produced from natural gas. The composition of AdBlue® makes it a biodegradable, non-explosive, non-toxic and non-flammable liquid. This liquid reduces the carbon footprint of your car and is used in many vehicles, from trucks to tractors, to vans and to cars. Heavy goods vehicles were the first to be affected by the European regulation, being equipped with AdBlue® tanks since 2005. AdBlue® meets the criteria of ISO 22241-1 to 4 and is registered as a trademark by the VDA ( German Association of the Automotive Industry).
AdBlue® is used by modern SCR (Selective catalytic reduction) systems as a way to help reduce the emissions of nitrogen oxides of your car. Since 2005 European standards have aimed to reduce the emission of pollutants from diesel cars by imposing limits for the emission of nitrogen oxides. The European standard Euro VI in force since September 2014 has reinforced these limits in order to reduce the impact on the environment of pollution produced by diesel vehicles. Many car manufacturers have since chosen to equip their cars with the SCR system, which is a technology of post combustion exhaust processing that converts the harmful molecules of nitrogen oxides in a catalyst and allows the reduction of the level of pollution of diesel cars! In this way AdBlue® powers this SCR system by circulating in an independent tank to that of the diesel. Most manufacturers have adopted this technology. Renault, Peugeot, Citroen, Mercedes-Benz, Opel, etc.
When your diesel car is running, the combustion of fuel pollutes by producing nitrogen oxides due to the combination of nitrogen with oxygen. AdBlue® is injected into the exhaust stream located between the engine and your car’s SCR catalyst. At high temperatures AdBlue® turns into ammonia and carbon dioxide. When the nitrogen oxides react inside the catalyst with the ammonia, the harmful NOx molecules are transformed into harmless nitrogen (N2) and water (H2O). This chemical reaction shows us that the impact on the environment of the car decreases. NOx + NH3 = H2O + N2.
It is necessary for your AdBlue® tank to always be filled so that the SCR system functions correctly. If your tank is completely empty, your car will no longer start. A warning appears on your vehicle display to alert you when it needs to be filled.
AdBlue® freezes at -11° and decomposes into ammonia at 70°C. Above 30° AdBlue® starts to decompose. Contamination by dirt can make AdBlue® unusable. Your AdBlue® is best kept under optimal conditions to increase its shelf life. For more information, refer to the « Filling Up » section.