Since the popularization and application of SCR, due to the different use of urea and filling oil products, it may cause the post-treatment to report the fault light from time to time, accompanied by the problem of torque limitation, such as one-time maintenance in the station, and the maintenance cost is high. If you want to avoid the maintenance costs caused by these faults as much as possible, you have to pay "attention" to urea selection, driving habits and fuel filling. But first of all, card friends still need to have a deeper understanding of SCR, the big "affectation" in post-processing.
Compared with other components of post-processing system, SCR system has higher failure probability and maintenance cost, so we give it a nice name - big "affectation". Inside the SCR system, there is a basic chemical reaction formula:
·(NH2) 2CO (urea) + H20 → CO2 + 2nh3
·4NO + 4NH3 + O2 → 4N2 + 6H20
·2NO2 + 2NO + 4NH3 → 4N2 + 6H20
We add urea into the urea tank, and then the ammonia generated after urea hydrolysis is used to treat the nitrogen oxides (nitric oxide and nitrogen dioxide) polluting the air. This is the basic principle of SCR system.
In addition, the working environment of SCR system is called carrier, which looks like a sponge. Generally, the material of carrier is TiO2, V2O5 is the main active ingredient, and WO3 and MoO3 are antioxidant and anti-toxic auxiliary ingredients. If this thing breaks down, it is very expensive to repair it once. Behind the carrier, there will be a device similar to the "supervision" post, called nitrogen and oxygen sensor. Once the content of nitrogen and oxygen compounds exceeds the standard, it will limit the torque of the engine in the form of "fault".
Understand the working principle and look at the causes of common faults. Typical urea crystallization is blocked. When choosing urea, some card friends have no concept of brand and production standard. When using inferior urea, due to the concentration and purity of urea can not meet the standard, the impurities that react precipitate on the surface of the carrier and vicious cycle. Finally, the carrier is blocked and the reactants cannot enter, resulting in torque limitation of the engine.
Compared with other components of post-processing system, SCR system has higher failure probability and maintenance cost, so we give it a nice name - big "affectation". Inside the SCR system, there is a basic chemical reaction formula:
·(NH2) 2CO (urea) + H20 → CO2 + 2nh3
·4NO + 4NH3 + O2 → 4N2 + 6H20
·2NO2 + 2NO + 4NH3 → 4N2 + 6H20
We add urea into the urea tank, and then the ammonia generated after urea hydrolysis is used to treat the nitrogen oxides (nitric oxide and nitrogen dioxide) polluting the air. This is the basic principle of SCR system.
In addition, the working environment of SCR system is called carrier, which looks like a sponge. Generally, the material of carrier is TiO2, V2O5 is the main active ingredient, and WO3 and MoO3 are antioxidant and anti-toxic auxiliary ingredients. If this thing breaks down, it is very expensive to repair it once. Behind the carrier, there will be a device similar to the "supervision" post, called nitrogen and oxygen sensor. Once the content of nitrogen and oxygen compounds exceeds the standard, it will limit the torque of the engine in the form of "fault".
Understand the working principle and look at the causes of common faults. Typical urea crystallization is blocked. When choosing urea, some card friends have no concept of brand and production standard. When using inferior urea, due to the concentration and purity of urea can not meet the standard, the impurities that react precipitate on the surface of the carrier and vicious cycle. Finally, the carrier is blocked and the reactants cannot enter, resulting in torque limitation of the engine.
