四驱车低速加速轰鸣问题分析与优化

Analysis and Optimization of Low-speed Acceleration Booming in AWD

文章以某纵置四驱SUV低速加速1400rpm和1700rpm车内存在明显轰鸣声为例,通过传动系统转速波动测试、CAE模态和传递函数分析结合整车模态匹配表快速确定了1400rpm轰鸣声是由后副车架45Hz刚体模态被激发出来与车内声腔模态耦合形成,1700rpm轰鸣是发动机2阶激励将顶棚前横梁二阶模态53Hz激发出来与车内49Hz声腔模态耦合产生。通过在后副车架增加45Hz动力吸振器和前顶棚横梁加3.0kg质量块使1400rpm、1700轰鸣分别降低4.2dB(A)、6.8dB(A)。同时探讨了通过对TCU换挡策略进行标定能快速有效降低轰鸣6.2dB(A),为解决整车低转速轰鸣提供了一种新颖的指导思路。

An AWD(All Wheel Drive) SUV appeared obvious booming at low-speed acceleration of 1400rpm and 1700rpm. Meta-analysis of powertrain system speed fluctuation test, CAE modal and transfer function analysis, the vehicle modal matching table were carried out to determine the booming cause quickly. It was determined that the booming of 1400rpm was caused by the rearframe rigid modal 45Hz coupling with the acoustic modal 49Hz of the cavity. The booming of 1700rpm was caused by the local modal 53Hz of the roof crossbeam which was excited by the engine coupling with the acoustic modal 49Hz of the cavity. In order to eliminate the serious booming, a dynamic vibration absorber was designed on the rearframe and 3.0kg additional mass was attached to the roof crossbeam. Finally the interior noise of the vehicle was reduced by as much as 4.2dB(A)and 6.8dB(A).Additionally, the TCU(Transmission Control Unit) calibration can be use to lower the booming 6.2dB(A) promptly and effectively, providing a novel solution of the vehicle low-speed acceleration booming.