三缸机传动系扭振引起的车内低频轰鸣声问题研究

Research on Interior Low-frequency Booming Induced by Torsional Vibration of 3-cylinder Engine Driveline System

传动系统扭振引起的车内低频轰鸣声,一直是汽车NVH领域的难点和热点问题。针对某型三缸机中型多用途汽车的中油门加速,在1400-2000r/min发动机转速时的车内低频轰鸣声问题,基于半消声室转鼓试验研究,运用相关性分析方法,锁定了传动系扭振为该问题的激励源,并通过传递路径分析,识别了前风挡玻璃与一阶空腔模态的受迫/耦合共振,是导致车内空气压力脉动升高并产生低频轰鸣声的主要原因。通过车身传递路径的优化,降低了车内低频轰鸣声2-4dB(A),显著提升了加速工况的车内声品质,为车内低频轰鸣声问题的优化提供了指导。

The low-freguency roar in the car caused by the torsional vibration of the transmission system is a difficult and hot issue in the field of automotive NVH. Aiming at the low-frequency roar of a three-cylinder medium-sized utility vehicle when the middle throttle is accelerating at 1 400-2 000 r/min engine speed,based on the semi-anechoic chamber drum test research,the correlation analysis method is used to find out that the drive train torsion vibration is the excitation source of this problem,and through the analysis of the transmission path,the forced/coupled resonance between the front windshield and the first-order cavity mode is identified,which is the main reason for the increase in air pressure pulsation in the car and the low-frequency roar. Through the optimization of the vehicle body transmission path,the low-frequency roar in the car is reduced by 2-4 d B( A),and the interior sound quality of the acceleration condition is significantly improved,which provides guidance for the optimization of the low-frequency roar in the car.