Vibration Isolation Performance Analysis Of Vehicle Powertrain Mounting And Sub-frame System

NVH is the main indicators of the performance of automotive products, is also one of the factors to consider when consumers buy a car. Engine powertrain mounting system is an important subsystem of vehicle vibration research, engine vibration is the main source of vibration, has an important influence on the NVH performance of the automobile. Sub-frame mainly has two level vibration isolation effect in the vehicle. In this paper, the vibration isolation performance of powertrain mounting and sub-frame system is studied, the effect of the sub-frame in the suspension and the sub-frame vibration isolation system is analyzed.Firstly, according to the CAD model of the sub-frame, establish the finite element model of the sub-frame in Hypermesh, simulate and calculate the finite element model of the sub-frame in the Optistruct module. Generate a MNF document of finite element model of sub-frame in Optistruct module, establish the flexible body model of the sub-frame in the ADAMS/View, and verify the validity of the model.Secondly, based on the simplified principle and the parameters, establish the dynamic model of suspension and powertrain. The dynamic model of the suspension element and the dynamic model of powertrain together with the dynamic model of the flexible sub-frame, through the connection between the subsystems, the dynamic model of powertrain mounting and sub-frame vibration isolation system is established.Then, analyze the inherent characteristics of powertrain mounting and sub-frame system in the ADAMS/Vibration module, do dynamic simulation analysis of powertrain mounting and sub-frame system in ADAMS/View. Optimize the powertrain mounting and sub-frame system, analyze the vibration isolation performance of the optimized system, finally obtain vibration isolation system which meets the performance requirements.Finally, introduce the principle of the sub-frame vibration isolation, introduce and expound the concept of the two stage vibration isolation of the sub-frame. Establish the dynamic model of the powertrain mounting system without sub-frame, analyze the inherent characteristics and vibration isolation performance of powertrain mounting system without sub-frame. Analyze the function of the sub-frame in the vibration isolation system, and through the analysis of powertrain rear suspension upper point, down point, the body point connected to and sub-frame acceleration RMS, further interprete two stage vibration isolation effect of the sub-frame.