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what is def urea

What is Def Urea Use?

Diesel exhaust fluid (DEF), also marketed as AdBlue and known as AUS 32, is a liquid employed to minimize the level of air pollution produced by diesel engines. DEF is a liquid solution consisting of 32.5% urea and 67.5% deionized water, formulated as an aqueous urea solution.

Since diesel vehicles are mostly large trucks and vans, many people know very little about automotive urea.  What is the use of automotive urea?

Unlike gasoline engines, diesel exhaust pollution is mainly dominated by NOx and carbon particles (we generally filter carbon particles through particle traps installed in the exhaust system). NOx in diesel exhaust is mainly nitrogen monoxide (NO). If the concentration of NO is too high, it can affect the human chest and lung function and cause damage to the central nervous system. At the same time, it is slowly converted to nitrogen dioxide (NO2) in the air.NO2 has a strong irritating odor. Inhalation can cause human respiratory diseases and is one of the main causes of acid rain. This is very harmful to people and the environment. 

Urea is used in selective catalytic reduction (SCR) systems in diesel vehicles to reduce harmful emissions of nitrogen oxides (NOx).Urea is injected into the exhaust stream where it reacts with NOx on a catalyst to form harmless nitrogen and water vapor.This process helps diesel engines meet stringent emissions regulations and improve air quality.

Importance of adding DEF urea

  • If the staff found in the annual inspection did not add urea, not only the audit will not pass, but also face the corresponding penalty.
  • Exhaust emissions do not meet the standards, polluting the environment, jeopardizing the environment for future generations, and become a thousand sins.
  • If there is no urea solution circulation for a long time, it will cause nozzle clogging, dry burning damage to the urea pump, crystallization of the pipeline, etc., which will eventually lead to the scrapping of the whole SCR system.
  • ECU detects that the owner has not added urea, it will limit the torque and the engine will not work hard.


what is adblue and what does it do?

AdBlue is the trademarked brand name for Diesel Exhaust Fluid (DEF). AdBlue is a highly purified solution that meets stringent international quality standards, including ISO 22241. It is a key component in meeting emissions regulations in many countries, including Europe and North America.

AdBlue is stored in a separate tank on the vehicle and injected into the exhaust system as needed to reduce NOx emissions.
AdBlue is a highly purified solution that meets stringent international quality standards, including ISO 22241. The composition of AdBlue is standardized to a urea concentration of 32.5%, with the remainder being water.

The solution must be handled with care as it crystallizes at low temperatures and can damage the SCR system if contaminated with dirt, dust or other impurities. AdBlue consumption varies according to vehicle type, usage and operating conditions, with typical consumption rates of 2% to 5% of diesel consumption.

Regular refilling of the AdBlue tank is essential and most modern diesel vehicles are fitted with a warning system to alert the driver when the AdBlue level is low.


AdBlue Urea can he be used on gasoline cars?

No. The purpose of AdBlue is to reduce harmful nitrogen oxide (NOx) emissions from diesel engines during the combustion process.

On the other hand, gasoline engines typically use different types of emission control systems, such as three-way catalysts (TWC) or gasoline particulate filters (GPF), which do not require AdBlue or diesel exhaust fluid (DEF).

Therefore, AdBlue is automotive urea for diesel engines with SCR systems and should not be used in gasoline engines.

How many miles will 10 liters of AdBlue (DEF Urea) last?

On average, 10 liters of AdBlue is enough for most drivers to cover a distance of about 6 to 8,000 miles.

However, this can vary greatly depending on the

  • Make and model of vehicle
  • driving conditions
  • usage patterns

Some heavy-duty diesel vehicles may consume AdBlue at a faster rate and require more frequent refills, while smaller diesel vehicles may consume AdBlue at a slower rate and require less frequent refills.

It is important to check the AdBlue level regularly and top up the tank when necessary to ensure the vehicle’s SCR system is functioning correctly and to avoid any potential damage or emissions problems.

Can I replace AdBlue (Diesel Exhaust Fluid) with water?

AdBlue cannot be replaced with water in vehicles equipped with Selective Catalytic Reduction (SCR) systems.

The urea in AdBlue breaks down into ammonia when injected into the exhaust stream and reacts with NOx via a catalyst to produce harmless nitrogen and water vapor.

Replacing AdBlue with water can cause serious damage to the SCR system.Water has different chemical properties than AdBlue and can cause SCR system failure by clogging the injectors or damaging the catalyst.

The resulting damage to the SCR system can reduce engine performance and actually increase fuel consumption per mile or kilometer, resulting in lower efficiency and higher operating costs.

It is therefore important to always use AdBlue in diesel vehicles equipped with SCR systems and to avoid the use of water or any other alternatives.AdBlue is available at most gas stations and auto parts stores and should be stored and handled with care to ensure its purity and effectiveness in reducing emissions.

How to store AdBlue (DEF Urea)?

Generally, AdBlue can be stored for up to one year in sealed containers, such as intermediate bulk containers (IBCs) or storage tanks, without significant loss of quality.

However, the actual shelf life of AdBlue may vary depending on a number of factors, such as storage temperature, sunlight exposure, and exposure to impurities or contaminants.

Over time, the quality of AdBlue may begin to deteriorate even if it has not yet reached its shelf life, which may affect its effectiveness in reducing emissions.

To ensure the quality and effectiveness of AdBlue, it is important to store it properly in a cool, dry place away from direct sunlight and heat sources.

The container should be sealed to prevent contamination by dirt, dust or other impurities.

It is also recommended that AdBlue be used within six months of opening the container to minimize the risk of degradation and ensure optimal performance. It is also important to check the AdBlue level regularly and refill the tank as necessary to avoid any potential damage or discharge problems.

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