纯电动客车振动试验分析及动力总成隔振优化

汽车电动化使动力总成的振动噪声特性发生很大变化,带来了新的NVH问题,作为短途客运主要运输工具的纯电动客车尤为明显。针对某纯电动客车在行驶中存在振动较大的问题,结合实车试验与理论仿真,研究其振动传递特性及隔振优化。首先,基于LMS Test.lab振动噪声测试平台,采集了车内地板与底盘关键点的振动信号进行振动试验分析,根据车内地板振动响应特性对18条振动传递路径进行振动贡献量分析,求解出各个传递路径对车内目标点振动的贡献量,确定振动的主要贡献路径。其次,根据传递路径分析结果,针对主要贡献路径上的减振关键环节(动力总成悬置)进行隔振性能分析,结果显示电机动力总成悬置系统较差的隔振性能是引起车内振动过大的主要原因。为此,进一步建立了六自由度动力总成优化模型,采用多岛遗传优化方法对悬置系统参数进行优化匹配设计。结果表明,悬置系统的隔振性能获得了显著提升,车内振动过大问题得到有效解决。

Vibration test analysis and powertrain vibration isolation optimization of pure electric bus

Vibration and noise characteristics of powertrain are greatly changed by vehicle electrification to bring new NVH problems,especially,the pure electric bus,as the main means of short distance passenger transport.Here,vibration transmission characteristics and vibration isolation optimization of a pure electric bus were studied based on real vehicle tests and theoretical simulation.Firstly,based on the software LMS Test.lab vibration and noise test platform,vibration signals of key points on the bus floor and chassis were collected to do vibration test analysis.According to vibration response characteristics of the vehicle interior floor,vibration contribution amounts of 18 vibration transfer paths were analyzed,respectively,and the contribution of each transfer path to vibration of the target point in the vehicle was calculated to determine the main contribution path of vibration.Secondly,according to the results of the transmission path analysis,the vibration isolation performance of the key link(Powertrain Mount)on the main contribution path was analyzed.It was shown that the poorer vibration isolation performance of the motor powertrain mounting system is the main reason for excessive vibration in the bus.Therefore,a 6-DOF powertrain optimization model was further established,and the multi-island genetic optimization method was used to do optimization and match design for parameters of the mounting system.Results showed that the mounting system’s vibration isolation performance is significantly improved,and the problem of excessive vibration inside the pure electric busis effectively solved.