Vehicle urea solution was first used in Europe. It is called ADBLUE. North America is called DEF (DIESEL Exhaust Fluid). 

ADBLUE is a liquid solution that is used in diesel engines, particularly in heavy-duty vehicles such as trucks and buses, to reduce harmful emissions. ADBLUE is a trade name for a solution consisting of urea and deionized water. It is also known as Diesel Exhaust Fluid (DEF) in some countries. ADBLUE is a critical component in reducing nitrogen oxide (NOx) emissions from diesel engines, which are harmful to the environment and human health.

Working principle of ADBLUE 

AdBlue is a solution made from urea and deionized water that is used in diesel engines to reduce harmful emissions of Nitrogen Oxide (NOx). It is injected into the exhaust system after the combustion process, and it reacts with the NOx in the exhaust gas to form harmless nitrogen and water vapor. This reaction takes place in the catalytic converter, where the AdBlue is converted into ammonia gas, which then reacts with the NOx in the exhaust to produce nitrogen and water.

When diesel fuel is burned, it produces nitrogen oxides, which are harmful to the environment and human health. AdBlue is injected into the exhaust system of diesel engines, where it reacts with the nitrogen oxides to convert them into harmless nitrogen and water vapor. This process is called Selective Catalytic Reduction (SCR) and is an effective way to reduce the emissions of harmful pollutants from diesel engines. AdBlue is stored in a separate tank on the vehicle and is automatically injected into the exhaust system as needed.

The SCR catalyst is made up of a material that has a chemical reaction with the Adblue solution, which leads to the reduction of NOx emissions. The catalyst contains a number of small channels coated with a substance that helps to facilitate the reaction between the Adblue and the NOx.

The AdBlue solution is stored in a separate tank in the vehicle, and the consumption rate depends on the engine load and driving conditions. The system requires periodic refilling of the AdBlue tank, usually during normal vehicle servicing.

In conclusion , the working principle of ADBLUE is quite simple. It is a liquid solution that is injected into the exhaust system of diesel vehicles, where it reacts with the nitrogen oxides (NOx) present in the exhaust gases to convert them into harmless nitrogen and water. The use of ADBLUE has several benefits, including the reduction of harmful emissions, improved fuel efficiency, and extended life of the catalytic converter.