Study On Vibration Testing And Vibration Isolation Optimization Of Gasoline Engine

Recently, the domestic commercial vehicle went through a very fast developmentaccompanied by the yearlyAlong with the rapid development of automobile industry, the quantity of domesticautomobiles increases quickly, which makes the vehicle noise become the important citypollution. Automobile noise and vibration affect a lot on the ride comfort and health ofdrivers and passengers, driving safety and a series of issues. Powertrain vibration and noisecontrol is the key to solve the problems caused by of automobile noise and vibration. Theassembly method, mounting position, suspension stiffness, BIW and the vehicle vibrationcharacteristics of powertrain will affect the vibration and noise more or less. Therefore,matching the powertrain to the vehicle in the early development stage is the key to solvethe vehicle vibration and noise problem. To match the powertrain as well as possible,accurate measurement of its noise and vibration characteristics is the key.This paper mainly covers the powertrain mounting system noise and vibrationmeasurement and vibration isolation optimization. The test equipments, test method anddata analysis of engine vibration and noise bench test was described in detail. Through theADAMS model of powertrain mount system, the vibration isolation and modalcharacteristics were analyzed and optimized. The optimization effects were verifiedthrough a series of experiments.Compared with the full vehicle test, engine bench test can measure the vibration andnoise more systemically. Meanwhile, the bench test is not affected by vehicle and otherenvironmental factors, which makes the engine vibration and noise characteristic can beobtained more easily. This characteristic offers a reference to the vibration and noiseanalysis of vehicle and powertrain. The engine vibration and noise test system in thisresearch composed of semi anechoic chamber and auxiliary system, silent air-conditioning, smoke control system and the dynamometer system, wherein the anechoic chamber and thedynamometer is the core part. Through the bench test, the vibration and noisecharacteristics of powertrain system can be obtained.In order to analysis the mount vibration isolation and to match optimization, theADAMS software was applied in the paper to built the rigid powertrain mounting systemmulti body dynamic model. Through this model, the modal analysis, and the mountingsystem mode coupling optimization were performed. Then based on the dynamicoptimization method, the test data of engine bench test measure was inputted to the model,and the mount dynamic reaction force were optimized in order to reduced the vibrationtransferred from the mounting system to the vehicle body and the sub-frame. Finally, theoptimized results were verified through the vehicle idle and WOT test by comparing thenoise and vibration of the mount and the interior cab.