The Matching Optimization Analysis Of Powertrain Mount System

Engine is one of the automobile’s main sources of vibration, which has a greatinfluence on the car’s comfortableness and the NVH performance. The practice and thetheory proved that the powertrain mounting system design is self-contradictory. Fromthe perspective of vibration isolation, the stiffness must be small. But from theperspective of limiting engine’s movement, the stiffness must be big enough. Also, themodal of the mount system is close to the modal of the suspension system. If they arematched unreasonably, it will lead to couple. So, matching the powertrain mountsystem reasonably can reduce the engine’s vibration to improve the vehicle ridecomfort. This paper matched the powertrain mounting system. The primary workincludes the following aspects.Firstly, the Matlab and the multi-body dynamics model of the powertrain mountsystem were established to analyze the intrinsic characteristics and the alternatingresponsiveness. Then, the powertrain mounting system’s energy decoupling rate andvibration isolation rate were optimized. The energy decoupling rate was solved withthe Matlab model and the vibration isolation rate was solved with the multi-bodydynamics model. Eventually, with the use of multi-objective optimization algorithmthe NSGA–II, the linear stiffness was obtained.Secondly, the nonlinear stiffness curve of the mounting system was designed andthe powertrain’s displacement and the rotation angle in different operation conditionwere checked. The car load analysis system software was developed. Throughinputting the vehicle parameter information, it quickly generated the report of the loadand displacement, which greatly shorten the mounting system development time.Thirdly, the matching method of the powertrain mount system and the suspensionsystem was studied. And the decoupling rate concept was introduced into the vehicleperformance analysis. The suspension system modal could not be equal to the naturalfrequency of the power system, and they could not be decoupled.Finally, the vibration isolation rate of the mounting system and the NVHperformance of the vehicle were tested. Through comparing the results, the mountingsystem optimization effects were verified.