Precautions for maintenance of SCR tail gas post-treatment system part1

Precautions for maintenance of SCR tail gas post-treatment system

1. The urea pump filter element of SCR system needs to be replaced every 3 years or 100000 km. If the application environment is harsh and the urea solution is seriously polluted, it shall be replaced according to the actual situation. Before replacement, it is necessary to clean the external surface of the urea pump and prevent the filter element area from being polluted by the outside during installation. When tightening the filter cover, use a torque of 20+5Nm. Replacement steps of urea pump filter element (take Bosch DeNOx 2.2 system urea pump as an example):
Unscrew the filter cover;
Take out the balancer;
Observe the color of the filter element. If it is gray, use the gray end of the professional tool; If it is black, use the black end of the tool. Insert the correct tool end into the filter element until a “click” sound is heard, indicating that the tool has been installed in place;
Pull out the filter element. If necessary, use the card slot of the tool to pull out with the help of other tools;
Clean the outer surface of the filter element cover with water; f. Lubrication filter element at both ends О Install the filter element (MobilVelociteNo.6 is recommended, and the use of other lubricating oils may lead to failure risk);
Tighten the filter cover.

2. The sealing plate at the bottom of the urea nozzle is a disposable part, which needs to be replaced after each disassembly. When replacing, do not use sharp tools to pry the edges. Use tweezers to move the three disc contacts. After removal, clean the sealing area but avoid touching the urea nozzle, and then reinstall a new sealing sheet.
3. Add urea solution to 100% of the maximum liquid level in the urea tank. When the urea solution is consumed to the remaining 20%, add the urea solution; Open the drain plug at the bottom of the urea tank for cleaning and discharge the sediment in the tank during engine maintenance every year; Check the urea tank irregularly. If white crystals are found at the vent valve or the filling port, wash it with clean water or wipe it with a damp cloth. If the vent valve is blocked, clean or replace it with clean water; Replace the filter screen in the box after 2 to 3 years of use; Irregularly check whether the plug-ins and pipe joints are in good condition.

3. Add urea solution to 100% of the maximum liquid level in the urea tank. When the urea solution is consumed to the remaining 20%, add the urea solution; Open the drain plug at the bottom of the urea tank for cleaning and discharge the sediment in the tank during engine maintenance every year; Check the urea tank irregularly. If white crystals are found at the vent valve or the filling port, wash it with clean water or wipe it with a damp cloth. If the vent valve is blocked, clean or replace it with clean water; Replace the filter screen in the box after 2 to 3 years of use; Irregularly check whether the plug-ins and pipe joints are in good condition.
4. The installation of urea pipeline shall be correct, and incorrect installation will cause the system to fail to work. Before installation, ensure that both ends of the pipeline are well protected to prevent dirt and impurities from entering the pipeline and then entering the system, leading to system failure. The urea pipe shall not be bent during installation, otherwise the system will not work.