Urea pump is an important part of urea solution injection metering system. Its main function is to extract the urea solution in the urea tank and maintain a certain pressure, and then deliver it to the injection unit to meet the requirements of the spray metering system for flow and pressure.

As an important means of controlling diesel engine exhaust emissions, it has been widely used in developed countries such as Europe, which has played a significant role in improving the environmental pollution caused by exhaust emissions. After using SCR technology, the emission function of engine largely depends on the calibration of urea injection system and the related performance of urea pump. Based on the basic principle of nitrogen and oxygen reduction, the SCR unit uses 32.5% urea aqueous solution as reducing agent to reduce NOx in exhaust gas to N2 and H2O under the catalysis of catalyst surface coating.

The exhaust temperature of diesel engine is generally 200-500 ℃, which basically meets the activity requirements of vanadium based catalyst used in SCR. Therefore, NOx in the exhaust gas of diesel engine reacts rapidly with urea aqueous solution to generate nitrogen and water.

Urea pump is the core component of SCR system. Its performance is closely related to the emission function of engine. In order to ensure the reliability of urea pump and meet the requirements of SCR system, it is necessary to calibrate the urea pump.

Selective catalytic reduction (SCR) technology is one of the NOx catalytic purification technologies for diesel engines to meet the future stringent emission regulations. It has the advantages of good safety, low fuel consumption and good sulfur resistance. Its working principle is to use urea solution and NOx oxidation-reduction reaction to generate non-toxic N2 to the human body and discharge to the atmosphere. Urea pump is to pump out urea solution from urea tank and transport urea solution to nozzle through delivery pipeline