| For the automobile cooling system,the electronic water pump is the core component of the system.With the continuous expansion of the new energy vehicle market,the market demand for the electronic water pump is also growing.Therefore,many manufacturers producing the electronic water pump will expand their production scale,and the factory test requirements for the electronic water pump should be improved.Therefore,it is not only necessary to improve the efficiency of the electronic water pump test equipment,but also to improve the accuracy and reliability of the test system.In this paper,in order to solve the problems of the traditional measurement of the electronic water pump with the coolant as the medium,such as long time-consuming and difficult to clean after measurement,through experimental research,the medium coolant is replaced with air,and an on-line test-bed of the automobile cooling system based on fans and various sensors is designed to make the factory test method of water pump cleaner and environmental friendly and reduce the subsequent cleaning problems.The main contents of this paper are as follows:Firstly,the online test-bed environment is built,which mainly includes the pump test-bed,hardware control system and software design.The on-line test-bed is mainly composed of the clamping device of the electronic water pump,the fan,the pipeline and various sensors.The hardware control system is based on STM32FZET6,which mainly includes the circuit design of the power module,the design of the control module and the design of the signal acquisition module.The software design part of the on-line test-bed includes the upper computer and the lower computer,both of which use RS485 for data transmission.The upper computer software is a graphical interface program developed based on QT,which mainly includes three module designs: parameter setting,system self-test program and test mainstream module.The parameter setting module is used to set the parameters of various test conditions of the pump to be tested,the system self-test and self calibration module is used to reduce errors and improve the system measurement accuracy,and the test process module is used to control the whole test process,complete the test and display the test results.The software of the lower computer is based on STM32 embedded development,which completes the functions of signal acquisition,frequency converter control and hardware self calibration.At the same time,relevant communication protocols are developed for the communication between the upper and lower computers,and the results are uploaded to the database after the test.Secondly,taking the electronic water pump produced by a company in Wuhan as a sample,the designed on-line test-bed is tested and the results are analyzed.The analysis shows that the online test-bed designed in this paper reduces the detection cost and is cleaner and more environmentally friendly than the system with coolant as the medium,and the measurement accuracy of relevant data meets the design requirements.Finally,through the analysis of the measurement uncertainty of the test-bed measurement system designed in this paper,it meets the specified standards and has good reliability.Through the establishment of fault tree,the reliability analysis of the measurement system is carried out.The life of the system is estimated to be 2770 h and the average repair time is estimated to be 20 min,which shows good reliability,and also puts forward the improvement direction for optimizing the system and improving the system reliability. |
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