In this paper, a vehicle model with 13 degree of freedoms is proposed for the influence of mounting system on the vibration at in-situ shift study. The dynamic response of the model during bump impact is calculated. The acceleration amplitude of powertrain centroid (X direction) during shifting process is used as evaluation index. The influence of rubber stiffness of mounting system and the installation position of torque strut on the powertrain vibration during in-situ shift process are analyzed. An optimization model taken by the rigid body modes and decoupling rate is proposed based on the genetic algorithm. The optimization results show that the vibration phenomenon of powertrain during shifting process can be improved by decreasing the rubber stiffness (X direction) of mounting system and adjusting the installation position of torque strut. The developed model and optimization method proposed in this paper is proved to be an effective reference for design and development of mounting system.%为了研究发动机悬置系统对汽车原地换挡振动的影响,建立了包含悬置系统的整车13自由度动力学模型,并利用模型计算得到了汽车原地换挡时整车的瞬态响应.把换挡时动力总成X向加速度幅值作为评价指标,分析了悬置刚度、下拉杆安装位置等参数对原地换挡时动力总成振动的影响.根据分析结果,结合动力总成刚体模态和解耦率的设计要求提出了改善汽车原地换挡振动的发动机悬置系统优化方法.结果表明:降低3个悬置的X向刚度,调整下拉杆Y、Z向安装位置可以有效改善动力总成在换挡时的振动.
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