A Study On Experimental And Calculation Methods For Rotational Vibration In The FEAD System

Engine front end accessory drive system is an important power transmission mechanism,the torque generated by the engine crankshaft through the belt to the attachment wheel-pump wheel,air conditioning compressor wheel,idler,generator wheel and tension wheel,providing power for the vehicle's normal operation of the working system.The research on the rotational vibration of FEAD system is of great significance to optimize the FEAD space arrangement position,ensure the transmission quality,reduce the vibration and noise and improve the dynamic performance of the engine.In view of the importance of the measurement and calculation of the rotating vibration of FEAD system,this paper mainly studies the following aspects:This study uses NI hardware and software platform,By comparing the performance and advantages of PXI?Compact DAQ and CompactRIO,the Compact RIO modular system is selected as the test platform from the cost,the test environment and other aspects of comprehensive consideration;The hardware of the test scheme and the sensor are selected,with the target of the minimum intervention and the disturbance of FEAD system.The rotating vibration model of the six-wheel FEAD system is established,and the real-time testing system of the FEAD system is established.This paper introduces the NI hardware and software for rotary vibration testing of the FEAD system.The evaluation parameters of the test system are discussed:The static and dynamic characteristics of the six-wheel FEAD system were measured.The dynamic tension of the belt on both sides of the tension wheel was measured;using the mathematical knowledge to get the engine crankshaft wheel speed and its volatility;The slip rate between the engine wheel and the belt was calculated from the relative speed between the attachment wheel and the belt.The edge of the most tight side of the belt with the lateral vibration and other parameters.A test system based on the LabVIEW platform for static tension,dynamic tension,the speed of the crankshaft wheel,slip rate and lateral vibration of the belt is built,The calculation method of the parameters such as the speed of the crankshaft wheel and the slip rate between the belt and the belt in the system were improved,andwriting the test program of the relevant parameters with the LabVIEW software,using the window,filter and other methods to deal with the signal processing to reduce the interference of other noise,the accurate measurement for the relevant parameters of the low perturbation in the FEAD system was achieved.It achieved that the dynamic tension of the belt,the fluctuation rate of the crankshaft speed,the slip rate between the generator wheel and the belt and the lateral vibration of the belt were shown and analyzed.The spectrum analysis of the crankshaft speed signal was carried out by using the data analysis function of LabVIEW,and the result of the spectrum analysis of the engine under steady state was obtained to judge the running state of engine;The order analysis of the engine crankshaft vibration signal was carried out to study the instability of the rotating vibration of the system,so as to ensure the accuracy of test results in the test system.The experimental results show that the FEAD system based on LabVIEW can meet the test requirements of the relevant parameters in the FEAD system.The test and analysis data from the FEAD system has a high application value for a further study on rotational vibration and the design of the FEAD system.