Have you heard of ADBLUE® or DEF?
Most of us have seen the word AdBlue® or DEF in car repair workshops, gas stations or auto supply stores. You might know it has something to do with newer diesel engines.
We know it has something to do with pollution and emissions regulations. But what is it really? Today we are going to try to explain it in the most detailed way possible.
AdBlue/DEF is the registered trademark of the product urea AUS32 (32.5% urea solution in deionized water), and is used to reduce nitrogen oxide (NOx) emissions caused by diesel engine exhaust, through a process called selective catalytic reduction (RCA)
How does it work?
A portion of a diesel engine is used to exhaust gases from the diesel fuel that is burned at high pressures and temperatures.
To save the maximum fuel, it is intended that this combustion occurs with an excess of air and the minimum fuel needed. This causes nitrogen oxides-NOx to be produced in the chemical process that takes place in the cylinder, which are polluting and harmful to the atmosphere.
After combustion in modern engines, most of the NOx that are generated are NO and NO2 and, to prevent them from going into the atmosphere, “a small chemical laboratory” is introduced into the exhaust of the vehicle. This “automatic laboratory” adds urea to the gases and causes them to react in the catalyst so that the nitrogen oxides are transformed mainly into nitrogen, water and CO2. All three are harmless and, although CO2 is a greenhouse gas, it is much less “active” than nitrogen oxides.
Most all modern vehicles with diesel engines are including AdBlue/DEF to comply with the newer emission regulations present in different parts of the world. Extra focus has been raised after the recent scandals that came to the light of some vehicle manufacturers incorporating computer programs designed to avoid emission limits.
But what happens if you operate your diesel vehicle without AdBlue/DEF?
In most vehicles there are two AdBlue/DEF low level alerts that warn you to refuel the AdBlue/DEF tank. If you are not careful and you run out of AdBlue/DEF during a trip, most vehicles are programmed to continue running without it until the engine stops. Once you stop the engine your vehicle without AdBlue/DEF in the tank, your vehicle will be immobilized or will only allow you to drive at a very slow speed depending on the vehicle manufacturer.
Where is the tank and who is going to fill in the AdBlue/DEF?
Generally, the AdBlue/DEF tank is usually filled from a port located next to the fuel tank
or under the hood.
If you are going to fill this tank by yourself, you must take into account a series of precautions:
- Use gloves and goggles to avoid contact with eyes and skin as it is a corrosive product.
- Try not to pour or spill on the upholstery and / or paint of the vehicle as this additive crystallizes in contact with the air.
- In case it spills on some surface and crystallizes, rinse with hot water until it is removed.
How to dispense AdBlue/DEF?
In case you want to dispense AdBlue/DEF in volume, there are numerous systems that incorporate pumps that move the fluid from a holding tank to the vehicle. These pumps are usually manual, electric or pneumatic with plastic components to be compatible with the fluid. Smaller capacity jugs (normally 2 ½ gallons) are also sold with the proper solution for dispensing by gravity.
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