The Experiment And Simulation Of Measurement Accuracy Of SCR Urea Pump

At present,the world's automobile power treat the technology of reducing NO_X emissions as one of the core technologies of the car,SCR technology has become the mainstream technology to reduce NO_X emissions.As one of the most important components of the SCR system,the measurement accuracy of urea pump has a direct impact on the efficiency of the system.It is necessary to control the measurement accuracy of urea pump within±5%under different operating conditions.The domestic research and development of urea pump on measurement accuracy is not up to the actual use requirements,to be further improved.In order to improve the measurement accuracy of urea pump,firstly,the structure principle of urea pump is analyzed,including urea pump,pump unit structure,arrangement of inernal pipeline and working principle,and the theoretical flow,instantaneous flow and flow uniformity of pump unit are analyzed in detail,to fully understand the internal flow characteristics of urea pump.Then the urea pump and pump unit measurement accuracy test device is designed,the calculation method of pump precision is clarified,the experiments on the type of air-assisted urea pump,pump unit and pump liquid road are studied,to study the change curve and the pros and cons of pump measurement accuracy.Based on AMESim,the modeling and simulation of the pump liquid road and the pump unit are carried out,and the simulation results are compared with the experimental results to verify the accuracy of the simulation model.At the end,the pump unit valve element displacement curve and flow curve are analyzed before and after optimization on pipeline,and the measurement accuracy tests on pump unit,pump liquid road and urea pump after optimization are done,the results are compared with the experimental results before,to reveal the extent of the effect of pipeline on the measurement accuracy of urea pump.In this paper,the influence of the flow curve,the measurement accuracy curve and the affect of pipeline is studied by the combination of simulation technology and experiment method.The results show that the variation of flow curve of urea pump is approximately sinusoidal,the flow pulse is large,the stability is poor;the measurement accuracy of urea pump is bad,does not meet the actual requirements;the simulation model and parameter setting of urea pump is approximately accurate,can reflect the dynamic characteristics of the system;through the pipeline optimization,the measurement accuracy of urea pump is greatly improved to meet the actual use requirements.