Vibration Isolation Optimization Of Automotive Powertrain Mounting System

As the progress of society and improvement of living, the customers pay moreattention to car NVH characteristics. Based on a powertrain mounting optimizationproject of an automotive manufacturer, in order to reduce the body vibration from theengine and improve the ride comfort, an effective optimization method is discussed.The content of this paper include below aspects:Firstly, for existing powertrain mounting system problem of poor vibrationisolation performance, vibration isolation performance test is carried out on thevehicle, the real problems are found and the subsequent optimization direction isdefined.Secondly, dynamic model of powertrain mounting system with six degrees offreedom is derived, natural frequency and decouple rate is calculated with Matlab,dynamic model is verified by Adams model. The calculated result shows the naturalfrequency and decouple rate of original mounting system need improving.Thirdly, according to the actual model, natural frequency and decouple rate ofmounting system are set as optimum objective, simulated annealing and geneticalgorithm (SAGA) is used to optimize the mounting rates. The optimized result showsbetter natural frequency distribution and higher decouple rate in the major vibrationdirection.Finally, in order to evaluate the vibration isolation performance in the vehicle,mathematic model of vehicle with sixteen degrees of freedom is also derived. Matlabsimulation model is built based on mathematic model. Mathematic model is verifiedby vehicle test data. The simulation result shows the vibration isolation performance atengine low speed is improved. Vehicle test also get the same result with the simulation.The study proves that the methodology and optimum arithmetic can be used tooptimize the design of powertrain mounting system and improve its vibration isolationperformance.