The Matching And Optization Of Automotive Powertrain Mounting System

Automobile powertrain is connected to the vehicle body by powertrain mounting system. While the engine acting as the power source, it also induce strong vibration and noise, the vibration will be transmitted to the car body by mounting system, which directly affects the NVH performance of a car; During a car driving, tires will have vibrational excitation to the vehicle, These vibrations can pass through the mounting system and then be transmitted to the engine, which affects the engine's life. Thus designing a reasonable matching mounting system, can not only improve NVH performance of a car, but also improve the reliability and safety of the entire vehicle.By referring to large amount of domestic and foreign relevant research materials,and based on the the vibrational isolation theory of the mounting system, this article adopts parameter optimization and structural optimization to a powertrain mounting system. The main contents of this research are as follows:(1) To establish the mathematical model of the mounting system by using the Lagrange equations, and analyze its inherent characteristics in MATLAB. Also, the six degree of freedom dynamic model of mounting system has been established in the ADAMS software, By comparing its inherent characteristics, the effectiveness of the established model has been validated. By simulation analyzing, found that the natural frequency of powertrain mounting system is beyond the experience value, and the coupling situation of the vertical direction and around the crankshaft direction are seriously. Short of the vibration isolation requirements.(2) Combining with practical engineering, to use the mount's three-direction stiffness as the design variables, to make the system's natural frequency and reasonable allocation of mounting element stiffness as constraint conditions, to maximize the energy decoupling rate of The vertical direction and around the crankshaft direction as the optimal objectives, the mounting system was optimized. After the optimization, the system's six order natural frequency has reduced from 26.27 Hz to 16.11 Hz, and decoupling rates in all directions have reached more than 90%.(3)Using ABAQUS software to have batch of calculation on different parameters structure of the rubber mount stiffness, Based on MATLAB platform, then to build up the neural network between stiffness and structural parameters, the target stiffness could map out the needed structural parameters of rubber mount. By using the single rank inverse Broyden iterative method, the structure of rubber mount components were iterative optimized when combining with ABAQUS, and the specific shape of the rubber mount that can satisfy the requirement of stiffness has obtained rapidly.This paper adopts the methods of analysis and optimization of the powertrain mounting system, which has certain reference value on improving the NVH performance of vehicles. Especially it presents a new rapid design method to satisfy the requirement of stiffness of rubber, which has certain reference significance.