Research On Design And Key Technology Of Electric Gear Type Urea Supply Pump

Selective catalytic reduction(SCR)is widely considered as the mainstream technology to reduce NOx emissions of diesel engines.In order to improve the conversion efficiency of SCR catalytic converter to NOx,it is necessary to precisely control the supply of urea solution and improve the injection quality of urea solution.In this paper,a new type of electric gear urea supply pump is designed,and its leakage characteristics,trapped fluid characteristics,pressure and flow pulsation characteristics and other key technologies are studied.Firstly,according to the functional requirements of the urea supply pump,the structure,driving mode,gears and materials of the urea pump are studied and selected.Focus on the design and calculation of special plastic gear,use CREO software for three-dimensional modeling and accurate modeling to achieve parametric design.Analyze and study the force bearing characteristics of gears and calculate the strength.A new type of tooth root circle transition curve is proposed,which is verified by finite element analysis.Secondly,according to the working principle of the urea pump assembly,a urea pump hydraulic test bench was designed and built.The pump body and gear of the urea pump were grouped and paired,to carry out the radial leakage test and axial leakage test.Through comparative analysis,the pressure,flow and volume efficiency of different pump bodies and gear samples of the urea pump after matching were obtained,and the influencing factors were determined.Finally,the one-dimensional hydraulic simulation of urea pump is carried out through AMESim software to provide data support for the boundary conditions of three-dimensional hydraulic simulation;The threedimensional fluid simulation of the urea pump is carried out by using Fluent software,and the rules and influencing factors of the urea pump’s leakage characteristics,trapped fluid characteristics,pressure and flow pulsation characteristics,volumetric efficiency,etc.are studied to determine a new unloading structure,which provides theoretical and experimental basis for the structural parameters of the gear and the commissioning parameters and working performance of the urea pump.