At present, SCR post-treatment system has been widely used in various types of commercial vehicles, but most truck users have insufficient understanding of the system and daily maintenance experience. Today, we will briefly introduce the working principle of the system and the matters needing attention in daily maintenance.

- Working principle of SCR post-processing system

SCR technology, namely selective catalytic reduction technology, converts NOx in exhaust gas into harmless nitrogen and water to reduce air pollution caused by automobile exhaust. The technology is commonly known as "urea system" because it uses AdBlue with specific concentration (32.5%) as the main reactant.

The system injects AdBlue (DEF) into the exhaust gas flow through an accurate metering pump. In the high temperature tail gas, AdBlue is atomized and decomposed into ammonia. Under the action of catalytic reducing agent, ammonia reacts with nitrogen oxide (NOx) in the tail gas to generate harmless nitrogen and water.

- Daily maintenance precautions for SCR post-treatment system

1. Check the AdBlue level every day. If it is found that the level is low, it should be added in time. The engine must be turned off before filling. And use a special filling pipe to keep the filling pipe clean when filling to prevent impurities from entering the AdBlue tank.

2. Pay attention to whether the emission fault light on the instrument panel of the vehicle is on. If it is on, go to the service station for repair and treatment as soon as possible when AdBlue is sufficient;

3. Do not start the engine immediately after power on when the vehicle is started, and start it after the vehicle system self inspection is completed; do not turn off the power switch immediately after stopping the vehicle. If the power is cut off immediately, the residual AdBlue in the urea pipeline will block the urea pump, pipeline or AdBlue nozzle, the power supply should be turned off after stopping for at least 30 seconds;

4. If proper amount of AdBlue needs to be stored for standby, light and high temperature should be avoided. Transportation temperature and storage temperature should be between - 5 ℃ and 25 ℃ and lower than - 5 ℃. Insulation measures should be taken. If the temperature is higher than 25 ℃, it should be cooled and the storage time should not be too long;

5. If the vehicle does not run for a long time, it is necessary to check whether the concentration of AdBlue reaches the standard when the vehicle is running again. If the AdBlue in the tank is not up to the standard, it shall be drained and cleaned, then added new high-quality AdBlue;

Note: clean water must be used to wash AdBlue tank or related accessories, and tap water is not allowed to be used;  AdBlue should be controlled below the scale mark on the  AdBlue tank in winter to avoid its freezing and bursting the urea tank;

6. Before driving, always check whether there is extrusion or leakage in the urea connecting pipe or joint. If any abnormality is found, please go to the service station for repair as soon as possible;

7. The consumption of  AdBlue in vehicles is usually 6-9% of diesel consumption. The actual consumption depends on the load and environmental conditions of the vehicle. It is normal for  AdBlue consumption to increase, decrease or not to consume under special working conditions;

8.  AdBlue has certain corrosivity, so it should be avoided to contact metal objects. In case of accidental eye contact, wash with plenty of water for at least 15 minutes and keep your eyes open during flushing; if you inhale carelessly, please transfer the person to fresh air. If the symptoms persist, it is recommended to see a doctor and explain that the intake product is 32.5%  AdBlue; if it comes into contact with clothes or skin, wash the skin with mild soap and plenty of water;

9. If the vehicle is on, a large amount of water must be used for cooling to avoid the sharp rise of  AdBlue tank pressure. High temperature will cause urea decomposition and explosion.

Note: The vehicle supplier will not be guaranteed for any damage to the parts of the vehicle's aftertreatment system due to the use of inferior  AdBlue. For your own car, please use high quality EverBlue's AdBlue for your vehicle to lower emission effectively.