How does the system work?
AdBlue®, a water/urea based operating fluid, is stored in a tank (like diesel fuel), however, unlike fuel it is not injected into the engine, but directly into a specially modified part of the vehicle’s exhaust. This begins a chemical reaction which removes the polluting oxides of nitrogen (NOx), converting them into harmless water and nitrogen in a process known as Selective Catalytic Reduction, or SCR for short. SCR is only applicable to diesel engines and the more economically you drive, typically, the less AdBlue® you will use.
The size of the AdBlue® tank fitted to your car will vary depending on which Volkswagen model you have, therefore the interval between top-ups will vary. In addition, many factors such as mileage, journey type, driving style and environmental conditions can influence how much AdBlue® is consumed. A passenger car can consume approximately 1.5 litres of AdBlue® every 620 miles (1.0–1.5 litres for the Passat and Passat Estate). The chart below details the AdBlue® tank size and location for all Volkswagen models that use SCR.
AdBlue® ? What is it ?
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 use d 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).
What is AdBlue® for ?
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.
What are the properties of AdBlue® ?
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.
How much to put in the tank ?
To find out the capacity of your AdBlue® tank, please refer to your car specification fact sheets. This will allow you to evaluate whether to purchase 5 or 10 litre canisters. Please note that a minimum of approximately 5 litres is necessary for your car to restart if you have completely run out of AdBlue®. In the meantime, you are still able to refuel with the canisters, which you can find in every petrol stations.
A label on each canister describes how to re-fill. It is recommended that you buy the smallest containers in order to carry them easily. That is filling will be made easier because holding up a 10L container for several minutes is not necessarily easy. And also, the 1.89L containers have a system that allows you to avoid overflowing the tank, unlike larger-volume cans.
Further, storing an AdBlue® container at home is not recommended because the AdBlue® deteriorates over time. The use of low-volume containers means there is less waste.
Dec. 21, 2017