What Is Adblue(diesel exhaust fluid) and How it Works

 

Why adblue (DEF) 

After BS6 norms vehicles must have to reduce their harmful emissions to environment, for this purpose we use adblue in diesel engines. Adblue is simply used for controlling the nitrogen oxides in exhaust gases of diesel engines. Adblue or DEF(DIESEL EXHAUST FLUID) converts the nitrogen oxides into nitrogen gas and water ,and the both are not harmful for environment 

BS (bharat stage)

The central government has mandated that vehicle makers must manufacture, sell and register only BS-VI (BS6) vehicles from April 1, 2020.

Bharat stage (BS) emission standards are laid down by the government to regulate the output of air pollutants from internal combustion engine and spark-ignition engine equipment, including motor vehicles.

 

The first emission norms were introduced in India in 1991 for petrol and in 1992 for diesel vehicles. Followed these, the catalytic converter became mandatory for petrol vehicles and unleaded petrol was introduced in the market

Ad blue

AdBlue is an exhaust fluid, not a fuel additive. It's stored in a separate reservoir and is topped up via a (usually) blue filler cap located either next to your fuel filler, in the boot or under the bonnet

AdBlue is a colourless, non-toxic solution of urea and de-ionised water. It’s not actually blue at all.

 How it works

     it is injected into the hot exhaust gas stream, the water evaporates and the urea thermally decomposes[6] to form ammonia (NH

3) and isocyanic acid (HNCO):

(NH

2)

2CO → NH

3 + HNCO

The isocyanic acid reacts with the water vapor and hydrolyses to carbon dioxide and ammonia:

HNCO + H

2O → CO

2 + NH

3

Overall, thus far:

(NH

2)

2CO + H

2O → 2 NH

3 + CO

2

Ammonia, in the presence of oxygen and a catalyst, reduces two different nitrogen oxides:[7]

4 NO + 4 NH

3 + O

2 → 4 N

2 + 6 H

2O and

6 NO

2 + 8 NH

3 → 7 N

2 + 12 H

2O

The overall reduction of NO

x by urea is then:

2 (NH

2)

2CO + 4 NO + O

2 → 4 N

2 + 4 H

2O + 2 CO

2 and

4 (NH

2)

2CO + 6 NO

2 → 7 N

2 + 8 H

2O + 4 CO

2