Maintenance and maintenance of “National VI” engine aftertreatment system components

With the continuous tightening of diesel vehicle exhaust emission standards by relevant departments, more and more car owners have begun to use urea for vehicles, especially after the implementation of the “National VI” standard, the original “adding water as urea solution” and “doing not add urea” The phenomenon that liquid can also be used” gradually withdraws from the stage of history.However, with the addition of the SCR exhaust gas treatment system, problems such as pipeline blockage, solution crystallization, and vehicle torque limitation also emerge one after another.Affect the use of the vehicle, investigate the reasons,The use of low-quality， automotive urea is one aspect, and the lack of maintenance and maintenance of the exhaust gas treatment system is also a part of the reason.

Today, let’s take the common electric drive urea system as an example to take a look at the common faults of the “National VI” engine aftertreatment system and its repair and maintenance.

01

Pipeline Crystallization

Failure analysis:

Tube crystallization is one of the most common problems encountered by car owners. When the vehicle starts and stops, there will be residual urea solution in the urea dosing pump and pipeline. Therefore, when the general vehicle is closed, the urea pump will clean up the residual urea, but when the heating effect is not good, the residual urea will not be completely cleaned, and the pipeline will be easily blocked.

Simple solution:

In an emergency, the pipes can be heated with boiling water or unplugged for manual cleaning. At the same time, the owner should also be careful not to turn off the power of the vehicle immediately after turning off the engine, so that the residual urea solution has time to react, and then close the pipeline after emptying.

02

Nozzle is clogged

Failure analysis:

The main reason for nozzle blockage is that the quality of the vehicle urea solution is not up to standard, and impurities in the solution accumulate at the nozzle, resulting in abnormal operation of the injection system.

Simple solution:

Remember not to use tools to clean manually. You can put the spray head into a discarded kettle and soak it in boiling water for a period of time. Because the urea solution will hydrolyze in water at 70-75°C, soak the spray head for more than 30 minutes. clean up. At the same time, in order to reduce the crystallization of urea, automobiles mainly choose compliant solutions.

03 The filter element is blocked

Failure analysis:

If the quality of the vehicle urea solution is not up to standard, not only the nozzle is easy to be blocked, but the filter element used to filter impurities in the solution will also be blocked, and its filtering effect will directly affect the cleanliness of the urea at the nozzle.

Simple solution:

Replace the filter element and take it out for manual cleaning in an emergency.