What is AdBlue? AdBlue explained

Since September 2015, AdBlue fluid has been introduced for all new diesel vehicles in response to global environmental concerns. Many manufacturers equip their newer models with systems that use the AdBlue fluid to produce less harmful and cleaner emissions.

AdBlue is set to play a big part in the greener future of the motoring industry, so it's important to know what it is and why you need it. To ensure that your vehicle aligns with emission standard regulations, we're here with a guide on all things AdBlue, covering:

  • What is AdBlue?
  • The science behind AdBlue
  • What is AdBlue used for?
  • What emission regulation does AdBlue follow?
  • What is the Euro 6 regulation?
  • Which vehicles use AdBlue Fluid?
  • AdBlue in Agriculture
  • What is the shelf-life of AdBlue fluid?
  • Is AdBlue flammable?
  • Can AdBlue freeze?
  • How can I estimate how much AdBlue I need for my fleet?
  • Where can I find an AdBlue supplier?

What is AdBlue?

AdBlue is not a fuel itself or a fuel additive; it's an exhaust fluid that has its own tank and is stored completely separately to your vehicle's fuel.

In short, AdBlue is essentially liquid urea. It's made up of 67.5% ionised water and 32.5 % urea. When the engine heats up, the AdBlue fluid gets hot and releases ammonia which acts as the catalyst. The ammonia causes a chemical reaction that converts nitrogen oxide into water and nitrogen – two completely harmless substances. These are then expelled as exhaust gases, mitigating the damage done to the environment by diesel vehicles.

When your vehicle is serviced, the AdBlue fluid should be topped up; however, you will most likely need to top it up once or twice yourself between your next service to comply with emission standards. A blue filler cap usually indicates where the AdBlue fluid should go, however always refer to your vehicle's manual first as older diesel vehicles may not require AdBlue.

What is AdBlue made from?

Now you know what AdBlue is, you might be wondering, what is AdBlue made from? There are two major AdBlue ingredients that make up the liquid. AdBlue is a colourless liquid made from a mixture of high-purity urea (32.5%) and deionised water (67.5%). The solution poses little risk to humans or the environment as it is mostly water-based.

AdBlue is made from an essential component of selective catalytic reduction, as ammonia, the active ingredient in AdBlue reacts with the NOx to neutralise it before it enters the atmosphere. As a result, there is a significant reduction of NOx in the exhaust fumes from diesel engines.

Is AdBlue made from pig urine?

There are many rumours about AdBlue ingredients and what AdBlue is made from. Though the chemical ‘urea’ is found in pig’s urine, AdBlue itself is not made from pig’s urine. Instead, it is a synthetic solution that is highly purified.

The science behind AdBlue

AdBlue is a colourless liquid that is made from a mixture of high-purity urea (32.5%) and deionised water (67.5%). The solution is an essential component of selective catalytic reduction (SCR) technology, which is one of the most effective systems for reducing the nitrogen oxide levels in the exhaust fumes that are outputted by diesel engines.

Nitrogen oxide is one of the most harmful pollutants emitted by engines, as it reacts with other gases in the atmosphere to form small particles and ozone, both of which can damage sensitive lung tissue in humans and animals.

When the engine burns the fuel, AdBlue fluid is injected into the selective catalytic reduction catalyst to convert the nitrogen oxide into a less harmful mixture of nitrogen and water vapour. The solution is stored in its own tank, separate from the diesel, before being added to outgoing exhaust gas by a dosing control system that supplies enough AdBlue to make up 2–6% of the total fuel consumption.

In the SCR catalytic converter, the urea present becomes ammonia when heated, reacting with the nitrogen oxide in the emissions to convert the pollutants into nitrogen, water, and a small amount of carbon dioxide —elements that are already natural to the air that we breathe.

What is AdBlue used for?

It's no secret that diesel engines produce a range of harmful air pollutants that can cause breathing and respiratory problems in vulnerable people. Nitrogen oxide and Nitrogen dioxide are the two most problematic emissions associated with diesel vehicles as they contribute to smog and acid rain. AdBlue is formulated to work with SCR technology. SCR is designed to remove the most polluting oxides from diesel exhaust emissions, and it uses AdBlue to achieve that.

AdBlue is one of the most efficient ways of keeping the nitrogen oxide levels in fuel emissions to a minimum; it has an incredibly important role to play in the future of diesel vehicles. You can increasingly see AdBlue stacked up on petrol station forecourts, as the motoring industry has for some time been taking steps to tackle the issues surrounding diesel emissions.

What emission regulation does AdBlue follow?

The Euro 6 regulation is the newest European emission standard for cars, and light commercial vehicles, whereby diesel cars have a limit of emitting 0.08g/km nitrogen oxide and petrol vehicles have a limit of 0.06g/km.

It's essential to have working knowledge on the AdBlue as every time you burn any fuel you will be outputting fumes, and therefore AdBlue will be used. All manufacturers producing vehicles in the EU/EEA have to ensure that their vehicles are tested to meet these acceptable emission levels. The incredible efficiency of an SCR system alongside AdBlue is the preferred test method used.

What is the Euro 6 regulation?

The Euro 6 regulation was first introduced in September 2014 and then later imposed for all new cars in September 2015. The only way most diesel cars of 1.6 litres and above will meet Euro 6 emission regulations is with the use of AdBlue fluid. Now, diesel cars are built with an AdBlue tank as it's a legal requirement that all diesel emissions meet the Euro 6 limits. You may well have noticed the presence of a smaller blue or black cap adjacent to the main fuel cap — this is for AdBlue.

Heavy-duty vehicles, like trucks and buses, have followed the Euro 6 regulation since December 2013. Although there are categories for different sizes, larger vehicles like buses and trucks are allowed a larger output of nitrogen oxide than cars and light commercial vehicles.

Which vehicles use AdBlue Fluid?

AdBlue has traditionally been used in agricultural vehicles, lorries, buses and coaches which have been using selective catalytic reduction (SCR) technology since the mid-2000s.

The simplest way to check whether you need AdBlue is to have a look under your fuel cap cover — if there is a secondary, smaller-cap that is black or blue adjacent to your main fuel cap, then you will require it. The secondary cap is often labelled with the product name to avoid confusion. Your owner's manual should also detail if there is an SCR system in your vehicle or not and what exactly needs to be done to maintain it.

If your AdBlue levels are low, most new vehicles will have a driver information system on board, which notifies you if there is a particular error or if you are running out of oils or fluids, including AdBlue - reminding you to refill soon.

AdBlue for Agriculture

At Rix Petroleum, we have been supplying AdBlue for many years to our valued agriculture and commercial customers. They have been using AdBlue for a long time in their tractors, trucks and other commercial vehicles, so are well aware of how it works and the benefits it brings.

Agricultural tractors and machinery were subject to emissions regulations laid out in EU directive 2000/25/EC, which set out a series of progressively more stringent requirements for the emissions of noxious pollutants from the exhausts of new tractors.

There were two new standards, Stage III and IV, which were adopted in 2005, and introduced further reduced limits. Stage III was phased in between 2006 and 2013, while Stage IV came into force in 2014, and is currently still the relevant legislation for newly manufactured vehicles. A Stage V standard has been adopted too, with plans to from 2019 onwards.

This new standard updated the previous ones and incorporated new lower limits for agricultural vehicles into the wider non-road mobile machinery standards. The lower limits require agricultural machinery manufacturers to make use of SCR technology, as well as Exhaust Gas Recirculation (EGR) and Diesel Particulate Filters (DPF), which can also help to lower nitrogen oxide and particulate matter (PM) levels in emissions.

What is the shelf-life of AdBlue fluid?

AdBlue can last up to 18 months in storage. To keep AdBlue in its optimal condition, store it:

  • out of direct sunlight
  • and at a temperature between -6°C and 25°C

If you store it at a higher temperature than this or in a vented container, the shelf-life will only be around six months.

Is AdBlue flammable?

AdBlue is not flammable, nor is it considered a hazardous liquid. It is a water-based urea solution and poses little risk to humans. If you have sensitive skin, it might be wise to wear gloves when handling the liquid to avoid any potential irritation. Although, be cautious not to ingest AdBlue or get it in your eye.

Can Adblue Freeze?

AdBlue does freeze, but the freezing temperature is -11°C, and it won't begin to freeze until -10°C. As the AdBlue tank on most vehicles is next to the exhaust, while the engine is running, you shouldn't have any problems. Vehicles that have the AdBlue tank situated elsewhere often have a system where it is heated with circulated engine coolant. Even if it does freeze, AdBlue will work perfectly well once it is thawed out.

How can I estimate how much AdBlue I need for my fleet?

When it comes to estimating the amount of AdBlue you will need for a fleet of vehicles, you should consider factors like:

  • How far each vehicle will travel
  • The fuel economy for each vehicle
  • How many vehicles are in your fleet
  • Your vehicles' AdBlue consumption rate

When the time comes to refill your AdBlue, the amount that you need will depend on the type of vehicle you are driving. Large trucks and coaches will have a much larger capacity than passenger cars to accommodate the larger volumes of the solution that will be used.

Most vehicles require a minimum amount of AdBlue to be refilled before the engine will work again if you are in a situation with an empty tank.

Where can I find an AdBlue supplier?

Rix Petroleum is an authorised reseller of AdBlue. We can supply AdBlue in several ways to suit your business and fleet requirements. Whether you are just looking to top up your car or you're searching for a larger quantity to maintain your fleet of trucks, there are a number of solutions that are just right for you.

Should you own or work for a company that owns several vehicles or a large fleet, it would be worth looking into purchasing your AdBlue in larger quantities such as in an IBC or bulk, especially if your vehicles regularly travel over long distances carrying heavy loads. You can save more by buying your AdBlue fluid upfront, rather than funding refills as and when they are needed, which will prove costlier.

Here at Rix Petroleum, we can supply the solution in 10L bottles that are perfect for a quick top-up or for keeping in your vehicle, in case you have to fill up on the go. We can also supply 200L drums or 1,000L intermediate bulk containers (IBCs), ideal for keeping multiple vehicles well-stocked with AdBlue for an extended period. Additionally, if you need a larger quantity, we can provide bulk deliveries too.

To find out how we can help you, fill in an AdBlue enquiry form and we will be happy to provide you with more information and a quote. If you want to know more about AdBlue, or any of the other fuels, lubricants or fuel additives we sell, please get in touch and speak with one of our industry experts today.