The commercial vehicle powertrain dynamics models with multi-rigid-bodies and mounting systems were set up, and the rigid bodies include power plant, AC compressor and propeller shaft. The vibrational modal characteristics of the multi-rigid-body powertrain with mounting systems were numerically analyzed, and parametrical studies were further carried out.The simulation and experimental modal analysis results show that the rigid-body vibration modes of power plant may be changed noticeably by the AC compressor coupled through its flexible driving belt, and therefore several modal frequencies are increased, which negatively affects the power plant vibration isolation. Fortunately, the effect of the propeller shaft inertia is negligible. On the basis of the numerical analysis, a suggestion was presented to improve the elastic coupling stiffness between power plant and AC compressor, etc.

以商用车动力装置-悬置系统为研究对象，分别建立了动力总成-空调压缩机-悬置系统模型和动力总成-传动轴-悬置系统模型，计算了以上两种多刚体-弹性系统的振动模态，进行了动力总成的刚体振动模态频率关于耦合子系统参数的变化历程分析。

计算和实验结果表明：空调压缩机通过其传动带与动力总成的耦合对动力总成的刚体振动模态有显著影响，使得动力总成-悬置系统的刚体振动模态频率提高了，不利于隔振设计目标的实现，但传动轴的影响较小。据此提出了关于动力总成-空调压缩机-悬置系统的弹性耦合刚度匹配改进建议。

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多刚体动力装置, 悬置系统, 振动模态, 弹性耦合, 商用车