drainage pit

Common faults and maintenance methods of urea pump - Sukorun

Working principle and internal structure of urea pump

Urea pump is the core component of SCR system, which is called “urea metering pump”. Its main function is to pump urea out of urea tank and deliver urea solution to nozzle through pipeline.

Internal structure of urea pump

The internal structure of urea pump is mainly composed of diaphragm pump, electromagnetic directional valve, pressure sensor, urea filter element, electric heating system, lead frame and other components. The outer side is composed of three urea solution pipelines: spray pipe, return pipe and inlet pipe.

Types of urea pumps

There are two types of urea pumps, one is the airless urea pump represented by Bosch, and the other is the air assisted urea pump represented by imitec and Cummins.

Common faults and maintenance methods of airless urea pump (taking Bosch urea pump as an example)

High urea pressure

Problem solving: it is reported that the urea pressure is high, generally the liquid return check valve is blocked, and a new liquid return check valve needs to be replaced.

Urea pump does not absorb liquid

Problem solving: urea pump does not absorb liquid, which is mainly caused by the insufficient spring force caused by the high pressure stamping on the electromagnetic directional valve. Just remove the directional valve, replace the spring, and then remove the check valve diaphragm under the motor.

Common faults and maintenance methods of air assisted urea pump

The power of the vehicle is insufficient and there is a problem on the instrument panel

Problem solving: the vehicle is lack of power and can’t run. Generally, it is caused by the car’s over 5 and over 7. The fault is reported. The main reason is that the reading value of no chemical sensor exceeds the standard, which leads to the car’s torque reduction and weakness. At this time, 100% of the problem is the post-processing problem. At the same time, the problem can be basically locked on the no sensor and urea pump. Test the no sensor and urea pump and the connection mode on the car to find out the cause of the problem And deal with it.

Urea pump does not absorb liquid

Problem solving: if the urea pump does not pump liquid, there is a problem in the liquid circuit of the urea pump; at this time, we will check the gas circuit of the urea pump to see if there is a problem.

The way to check the gas path: remove the bus bundle of the pump on the vehicle, connect the wire bundle to the pump with the equipment, ensure that the air pressure on the vehicle is 0.85mpa, and then click empty on the equipment. If there is gas coming out, it means that there is no problem with the gas path. If there is a problem with the gas path, solve the problem with fault 3.

Urea pump does not pump liquid is often urea pump check valve problems, or into the liquid quick plug caused by plugging.