动力总成悬置系统影响车内噪声的试验研究

以某乘用车加速工况车内噪声为研究对象，以悬置主动端支架模态频率和悬置动刚度为变量，系统性地试验研究了支架和悬置对车内噪声的影响规律。首先，设计并试制高、中、低三套模态频率不同的悬置支架并装车对比试验，结果表明，车内噪声水平主要由低频段噪声分量决定，中频段次之，高频段噪声分量的贡献可忽略；支架对车内噪声的影响在于其共振诱发的中频段噪声，一阶模态大于700 Hz的高频支架方案可有效降低中频段噪声。其次，液压悬置充、放液对比试验表明，悬置刚度主要影响低频段噪声，因而也决定着车内噪声水平。在此基础上，综合采用高频支架和倒置液压悬置的组合方案，有效改善了低频段和中频段车内噪声，进一步验证了前述结论。

EXPERIMENTAL STUDY ABOUT THE EFFECT OF POWERTRAIN MOUNTING SYSTEM ON VEHICLE INTERIOR NOISE

The effect of bracket and mount on the interior noise of a passenger car was studied by experiment systematically under an accelerated condition, taking the modal frequency of an engine side bracket and the dynamic stiffness of mount as variables. First, brackets with high, medium and low modal frequencies were designed and trial-manufactured, then the contrast experiment was carried out. The results indicate that: the overall level of interior noise is determined mostly by low-band noise, secondly by medium-band noise, and the contribution of high-band noise can be ignored. The effect of brackets on interior noise is caused by resonance-induced medium-band noise. Thusly, high frequency brackets with first-order modal frequency greater than 700 Hz can refine medium-band noise effectively. Secondly, the contrast experiment results between hydraulic mount and the one without fluid indicate that mount stiffness can affect low-band noise and therefor determine the overall level of interior noise. On the basis of above researches, the combination scheme was implemented with high frequency brackets and right up-side down hydraulic mount. Then low-band and medium-band noise are refined, and the above conclusions can be validated.