How AdBlue works

WHATS ADBLUE?

AdBlue is stored in a separate tank on the vehicle. It is precisely metered into the hot exhaust manifold where the urea solution breaks-down into Ammonia and reacts with exhaust gasses in the presence of a catalytic converter. 


The oxides of nitrogen formed at combustion are converted into harmless elementary nitrogen and water. This method is called Selective Catalytic Reduction (SCR). 
It is a common misconception that AdBlue is a fuel additive.

How much AdBlue will my vehicles use?

The consumption of AdBlue is 3-4 percent that of diesel for a Euro 4 engine, and 5-7 percent for a Euro 5 engine, depending on driving, load and road conditions.

AdBlue Consumption as percentage of diesel consumption	Euro 4	Euro 5
Light Duty  [City Traffic]	3.23%	4.79%
Medium Duty [Motorway Cruising]	4.14%	6.15%
Heavy Duty [Over the Alps]	4.23%	6.29%

The consumption in litres can also be calculated using the guideline figures is the table below.

AdBlue Consumption in Litres	Litres per week	Litres per month	Litres per year
44-tonne truck	30-40	160	2000
18-tonne runabout	20-25	100	1200

(source – DAF Trucks, AdBlue Conference, Brussels, June 2005) 
As vehicles will typically be fitted with a 70 or 90 litre AdBlue tank, most vehicles will need to be topped-up with AdBlue every week-to-ten-days.