Vibration Isolation Analysis And Design Optimization Of Vehicle Powertrain Mounting System

Automotive powertrain is one of the main vehicle vibration sources, while the carmounting system is a major component of the corresponding vibration control. Isolationperformance of powertrain mounting system has a great impact on improvingautomotive NVH (Noise, Vibration and Harshness, referred to as NVH). When theparameter of powertrain and vehicle have determined, a rational design of a vehiclepowertrain mounting system can significantly isolate vibration from being transmittedto the vehicle body. Effective isolation will increase a vehicle comfort and extend thedurability and lifespan of the engine and other vehicle components.This paper studies the powertrain mounting system vibration isolation for adomestic vehicle. This paper has optimized for powertrain mounting system based onmounting system modeling technology, energy decoupling theory and torque axisdecoupling theory. The primary work includes the following aspects.Firstly, through the theoretical and experimental analysis, the parameters ofpowertrain mount system are obtained. Based on those parameters, using the ADAMSsoftware the six degrees of freedom powertrain mounting system and is established. Thepaper also constructs a sixteen degrees simulation model with the powertrain, car bodyand suspension.Second, under the six degrees of freedom powertrain mounting system, theinadequacy of existing powertrain mounting system are found from mounting systemdecoupling rate, the maximal deformation of powertrain and mounts in the21conditions, the location of torque roll axis parallel and elastic axis. The inadequacy ofexisting powertrain mounting system indicates the direction for vibration isolationoptimization.Third, determining the optimal stiffness parameter optimization variables throughthe sensitivity analysis, mounting system design requirements to be the constraints,system main modes direction decoupling rate and rational allocation of the naturalfrequency for the objective function, the powertrain mounting system has optimized andvalidated under the energy decoupling method. The results show that powertrainmounting system decoupling rate modes in the main direction of more than90%, thebasic direction of the rest of the decoupling rate reached more than85%, the vibrationisolation capability of optimized mounting system is enhanced. Finally, based on the model of sixteen degrees simulation model, this papercompares the vibration performance and vibration coupling through vibration analysisand kinematic analysis in the21conditions. The result verifies the correctness andreliability of the optimization results.The sixteen degrees simulation model may be established as a means to verify themounting system optimized design results. The software that calculations the TRA andEA can shorten the mounting system development cycle. The parameter sensitivityanalysis method has some theoretical guidance for mounting systems optimizing.