轴系扭振诱发的车内异响诊断及优化

针对某涡轮增压轿车在加速过程中出现320~470Hz异响问题进行诊断与优化。首先,对异响特性及源头进行诊断,按照一般整车异响诊断流程,依次进行了基本的声振测试、机舱内声强测试以及燃烧测试,发现异响源自发动机且为整体扩散式异响,排除了燃烧激励起异响的可能性之后,判断异响由轴系振动引起;然后,进行小惯量扭振减振器(torsional vibration damping,简称TVD)的轴系扭振测试来验证异响与扭振的关系,时频图上显示异响频段内扭角特性与异响十分相似,断定异响源自轴系扭振;最后,针对装配大惯量TVD条件下的轴系进行扭振仿真计算,350Hz对一阶扭转模态具有最优的减振效果。依照仿真结果重新设计TVD进行试验,结果显示车内噪声异响频段内幅值衰减明显,主观评价"咕噜"音消失。本研究对于主流轿车的车内异响诊断和优化都具有着重要的指导意义。

machine vision; inertial measurement; multi sensors fusion; Kalman filtering algorithm; track alignment

Troubleshooting and diagnosis are proceeded for an abnormal noise problem of a vehicle with a turbocharged gasoline engine at accelerating condition. The frequency band of the abnormal noise is 320~470Hz. In order to get the time-frequency characteristics and sound source of the abnormal noise, tests of basic sound, vibration, sound intensity and combustion are proceeded. The experimental results reveal that the abnormal noise is radiated from every engine surface and has little connection with the combustion. Thus the crankshaft vibration is suspected to be the main cause of the abnormal noise. The torsional vibration tests of the crankshaft with different torsional vibration dampers (TVD) are executed, the time-frequency contour maps of the torsional angle have similar characteristics with the abnormal noise, affirming the former suspect. The simulation of the crankshaft torsional vibration is proceeded in order to find an optimum TVD, which is verified as the best vibration absorbing effect at 350 kHz. Then the optimized TVD is manufactured and tested, the indoor noise shows that the amplitude of 320~470 Hz is attenuated dramatically and the abnormal noise is eliminated successfully.