Business, Personal

AdBlue... What is it?

Posted on April 05, 2017

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AdBlue is a liquid that converts harmful NOx from your diesel vehicle exhaust into harmless nitrogen and steam, therefore considerably reducing the emissions of nitrogen oxides. AdBlue is very easy to use and is a harmless substance. It is not a fuel, nor a fuel additive but a high purity urea solution that must be used in a dedicated tank on your vehicle that should only be refilled as and when required.

Why are diesel vehicle exhaust systems such a big deal?

Diesel engines can be run with a lean burn air to fuel ratio, this is used to ensure that a correct combustion is carried out and to prevent unburnt fuel going out the exhaust. Unfortunately the excess air leads to harmful pollutants from the nitrogen in this excess air.

To reduce these harmful pollutants, a DPF (Diesel Particulate Filter) system is used to reduce the amount of harmful pollutants that gets released into the atmosphere. Effectively it is a highly developed filter that catches soot and these harmful pollutants before they reach the atmosphere.

If the DPF filter catches these harmful pollutants, does it eventually get full?

As with all filters or 'traps' they will eventually fill and need to be emptied. The DPF does this with a process called 'regeneration' or as its also known, a 'burn off' where the collected soot is burnt off at an extremely high temperature (400-800 degrees Celsius) to leave only a tiny ash residue.

To achieve this your vehicle will need to be driven in a motorway type scenario for an extended length of time, check manufactures recommendations for specifics. If regular burn offs are not carried out it can lead to blocked filters and added costs if you need to get this cleared.

Interesting, so how does AdBlue work with a diesel vehicle exhaust system?

AdBlue is injected into the exhaust pipeline, it then vaporises and decomposes to form ammonia and carbon dioxide. This breaks down the soot and harmful pollutants turning them into water and nitrogen (which are both harmless) and then releasing them through the exhaust.

It also reduces the temperature in which the DPF needs to perform its regeneration or burn off effectively extending the lifespan of the component and reducing unnecessary maintenance.