Simulation Analysis And Optimization Study Of A Vehicle Powertrain Mounting System

As a key component system of the vehicle,the powertrain mounting system plays an important role in the NVH performance of the vehicle.A reasonably designed powertrain mounting system can effectively improve the NVH performance of the vehicle.Due to the complexity of the vehicle system and the diverse driving conditions,there are still many deficiencies in the research on establishing ideal simulation models,simulating real driving conditions,and improving the efficiency of mounts development.In response to the above problems,this subject relies on the development project of a powertrain mounting system of a Shenzhen automobile factory,takes the horizontal powertrain mounting system as the research object,and focuses on the simulation model and optimization design method of the mount.The main research work is as follows:Firstly,this paper describes the rigid body mode of the powertrain based on the principle of vibration isolation,and establishes a 6-degree-of-freedom vibration model of the powertrain mounting system.This paper verifies the accuracy of the model by Adams,and develops the visual simulation software using MATLAB.this paper studies the dynamic characteristics of hydraulic mounts,establishes a vibration simulation model with higher degrees of freedom,and verifies the validity of the model.At the same time,this paper proposes a control method for the dynamic characteristics of hydraulic mounts.Secondly,this paper studies the vibration characteristics of the vehicle during start and stop conditions.By analyzing the excitation source of the horizontal inline four-cylinder engine,based on the 6-degree-of-freedom vibration model,this paper establishes a simulation analysis model for the start and stop conditions of the mounting system to solve the problem of vehicle body vibration that may not meet the standard during the simulation process,and proposes an optimization method.Then,this paper studies the multi-objective optimization problem of the mounting system.In order to solve the problem of low computational efficiency of single optimization algorithm,this paper innovatively proposes a hybrid algorithm combining multi-objective particle swarm optimization algorithm and non-dominated sorting genetic algorithm.Aiming at the test results of the classic test function,the improved hybrid algorithm proposed in this paper has higher solving efficiency.Compared with the previous two algorithms,the calculation time is shortened by 23.5% and 8%,respectively.Aiming at the problem that the decoupling rate of the application vehicle does not meet the standard,this paper is based on the improved hybrid algorithm to achieve the decoupling optimization of the mounting system.The results show that the decoupling rate in all directions of the optimized powertrain mounting system is greater than 90%,and the decoupling rates in the X,Ry,and Rz directions are increased by 24%,28.2%,and 23.3% respectively compared with that before the optimization.The key performance analysis of the optimized mount shows that the optimized mount meets the key performance target values.Finally,this paper verifies simulation and the feasibility and accuracy of the optimization method based on the real vehicle start-stop,idle speed and acceleration conditions.The results show that the simulation results can effectively predict the mount performance based on the actual driving conditions of the whole vehicle,and verify the effectiveness of the vibration simulation model,the start-stop vibration characteristics simulation model and the optimization method studied in this paper.It provides a reliable simulation model for the development of enterprise mounting systems,provides strong technical support for solving the problem of substandard decoupling rate in the mounting design process,and shortening the subsequent mounting system matching test time.It has important guiding significance and Engineering application value.