What is AdBlue®


DEF (Diesel Exhaust Fluid) is, at a chemical Level, a combination of deionized water and urea that transform harmful nitrous oxide emissions into harmless water and gas. AdBlue is the registered trademark of VDA for AUS32, or Aqueous Urea Solution 32.5%

def liquid for diesel engines

All modern diesel engines with selective catalytic reduction (SCR) units in their exhaust systems can benefit from DEF. These include diesel-powered vehicles such as trucks, buses, tractors, cars, vans and off-road vehicles.

SCR engines use a diesel exhaust fluid (DEF) such as AdBlue. The fluid is stored in a separate tank in the system and injected into the exhaust stream. This injection causes a chemical reaction in the SCR catalytic converter which turns oxides of nitrogen (NOx) into environmentally friendly components, diatomic nitrogen (N2) and water. As a result, selective catalytic reduction systems are being used as a sustainable and effective way of protecting the environment.

AdBlue will help your business to reduce harmful emissions and it will reduce your fuel costs by up to seven percent. The product can be stored for 18 months. It can be used in most weather conditions.

It is not a fuel, nor a fuel additive and needs to be used in a dedicated tank in your heavy-duty vehicle. It is replenished in a similar way to refuelling diesel. Should you spill AdBlue on your hands, simply wash it off with water.

Frequently Asked Questions

Q1: How much AdBlue do I need?

Average consumption of DEF is generally 3 ~ 5% of diesel use, so you will need to tank much less for AdBlue then you do for diesel. You will use about 3~5 litres of DEF to every 100 litters of diesel.

Q2: How should I store DEF?

DEF can be stored for 1 year if this is done in a correct manner i.e. away from direct sunlight. It needs to be protected from too warm or too cold temperatures. Its freezing point is at -11 degrees Celsius. When it thaws, the product will retain its initial quality. It should be stored in a sealed package and in a well-ventilated storage area.

Q3: Why should I choose SCR with DEF over other technologies?

DEF combined with SCR offers you a fuel-efficient solution, with lower CO2 emissions then competitive solutions. All major European and North American truck manufacturers currently offer SCR equipped models. The future BS VI emission standard is set to reinforce the demand for this technology in India.

Q4: Why does DEF quality matter?

Various actions can affect the quality of DEF. To prevent contamination, it is imperative that foreign matters do not come into contact with the solution. Using contaminated DEF can lead to expensive catalyst replacement costs. The AdBlue trademark is currently held by the German Association of the Automobile Industry (VDA), who ensure quality standards are maintained in accordance with ISO 22241 (ISO-22241-1, ISO-22241-2, ISO-22241-3) specifications. Ensure that you only buy a reagent for your heavy-duty vehicles that bears the name AdBlue with the registered trademark (®) on the product label. Buying AdBlue from PowerBlue is a guarantee of the correct specification required for use with your SCR technology.

SCR Technology

What is SCR technology for trucks, buses and off road heavy duty vehicles?

SCR stands for an after-treatment technology called Selective Catalytic Reduction. This technology requires the use of a reagent called AUS 32 (also known as AdBlue,DEF in North America or ARLA 32 in Brazil) to reduce the NOx. Almost all major heavy-duty vehicles manufacturers have decided to use this technology to meet the new emission legislation on NOx emissions. Competitive technologies offer a less beneficial fuel efficiency and higher CO2 emissions. So, SCR is the most cost-effective solution to meet NOx emission standards.

def urea for SCR vehicles

The main components of the SCR system are the SCR catalyst, the DEF injection unit, the DEF tank and the DEF dosing control unit. DEF is 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 reacts inside the catalyst with the ammonia, the harmful NOx molecules in the exhaust are converted to harmless nitrogen and water.

def liquid adblue urea

For the correct functioning of your SCR system, make sure you use only high quality DEF/AdBlue such as PowerBlue. Poor quality reagent that is contaminated with foreign matters risks damaging your catalyst.


There are different emission standards around the world, setting specific NOx emission limits that require the use of SCR and DEF. The four main pollutants covered by vehicle emission legislation are Oxides of Nitrogen (NOx), Particulate Matter (PM), Carbon monoxide (CO), and Hydrocarbons (HC).

In Europe, the first of these Standards, Euro 0, came into effect in 1990 with NOx limits of 14.4 and PM limits of 1.1, both measured in g/kwh. The 2001 Euro III standard reduced these limits to 5 and 0.1 respectively. The use of DEF came with the introduction of Euro IV, V and VI standards. NOx, particulate matter (PM), hydrocarbons (HC) and carbon monoxide (CO) are the components regulated. Euro IV was implemented from Oct. 2005 to Oct. 2006 and Euro V implementation dates were from Oct. 2008 to Oct. 2009. The Emissions limit for NOx is 3.5 g/kWh in Euro IV and 2.0 g/kWh in EuroV. Euro VI standard is implemented as from 2013-14 and will have a NOx limit of 0.4 g/kWh.

In the USA, emissions from vehicles are regulated by the Clean Air Act. The use of urea SCR NOx control is coming to the US with the implementation of the so-called US2010 emission standard, which is effective as of January 1st 2010 and sets the NOx emission limits at 0.3 g/kWh.

In Australia and New Zealand, the emission standards follow those of Europe with a few years delay. Euro IV was phased in from 2007 and Euro V will be implemented in 2010.

In China, the legislation is called National Standard IV and V. From 2008, National VI standard for heavy duty vehicles has reduced NOx limits to 3.5 g/kWh and PM limits to 0.02 g/kWh. This standard has been applied in Beijing since 2008.

In Brazil, the legislation is called PROCONVE - Programa de Controle da Poluição do Ar por Veículos Automotores and will be applied as from 2012. The reagent in Brazil is known as ARLA 32 and this acronym stands for Agente Reductor Liquido Automotivo.

In India, Bharat Standard IV or BS IV emission norms which are modelled after Euro Regulation and sets the limit for release of air pollutants from vehicles.

adblue urea liquid

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