Powertrain Mounting System Research Articles

Testing and Analysis on Vibration Isolation Performance of Vehicle Engine Mounting System

Aiming at the vibration test of the power train mounting system of certain light truck, a vibration test is performed, and vibration response at each testing point of the system is obtained in different conditions. Data is processed based on Matlab software, to display the time domain and the frequency domain response in an image way in each testing condition. The energy transfer efficiency of each mounting point, the vibration frequency domain response property, and the vibration intensities of the variable-speed joystick and the steering wheel in three directions are analyzed, a parameter design optimize proposal on the mounting system is proposed, and the vibration isolation effect can be improved by reasonably selecting parameters.

The design strategies and calculation methods for powertrain mounting system with multi-powertrain

Multi-powertrain is defined as an engine plus different transmissions, or a transmission plus different engines in this paper. To reduce mount cost and production time, the mounts in a Powertrain Mounting System (PMS) with multi-powertrain should have the same stiffness or the same configurations. On the basis of this requirement, the design strategies and calculation methods for PMS with multi-powertrain are presented in this paper. In designing Multi-PMS (MPMS), an optimisation method to select mount stiffness in its Local Coordinate System (LCS) and locations based on the requirements for six rigid body modes and energy distributions of a PMS with multi-powertrain is developed. Then a procedure of designing Force vs. Displacement (F-D) relation for a mount to control the motion of each powertrain in multi-powertrain is proposed.

Improved torque roll axis decoupling axiom for a powertrain mounting system in the presence of a compliant base

The existing torque roll axis decoupling theories for powertrain mounting systems assume a rigid foundation, thus ignoring dynamic interactions between the powertrain and other sub-systems. To overcome this deficiency, a coupled mounting system problem is formulated based on the linear time-invariant system theory. The influence of a compliant base on torque roll axis decoupling is first analytically examined in terms of eigensolutions and frequency responses. Then, a new analytical axiom is proposed based on decoupling indices as well as given the properties of the coupling matrix. Five examples are chosen to examine frequency and time domain responses given the torque excitation along the crankshaft axis. To satisfy the new condition, the mounting system is redesigned in terms of the stiffness rates, mount locations, and orientation angles. The results show that the torque roll axis of the redesigned powertrain mounting system is indeed decoupled in the presence of a compliant base (given oscillating or impulsive torque excitation). Finally, eigensolutions are validated by using published data.

Optimization for Powertrain Mounting System Based on Theory of Energy Decoupling

Comfortableness of cars is influenced obviously by engine vibration. Aiming at the vibration problem of passenger cars, this paper presents an optimal method for powertrain mounting system which bases on energy decoupling method. Firstly, a six-freedom dynamic model of powertrain mounting system of passenger cars is established. Then, an optimal process of mounting system is conducted by using the theory of energy decoupling with maximizing decoupling rate of the six-freedom mounting system as objective. The theory of energy decoupling and the elastic theory are applied to optimize the design of powertrain mounting system in Matlab software. Powertrain mounting system is implemented by ADAMS software. At last, optimal results of Matlab and ADAMS are compared. The comparison results illustrate effectiveness and rationality.

A method for calculating the displacements of a powertrain and mounts in a powertrain mounting system including torque struts under quasi-static loads

A modelling and calculation method for obtaining the displacements of the powertrain’s centre of gravity (CG) and mounts in a powertrain mounting system (PMS) including the torque struts under a static or quasi-static load is presented. A new mount model that is modelled as three-dimensional (3D) springs with both a translational stiffness along each axis of its local coordinate system (LCS) and a rotational stiffness around each axis of its LCS is presented. Also a torque strut is a generic construction and is regarded as a massless rigid body with a mount at each of its two ends. The equation and the solution method for estimating the displacements of the powertrain’s CG and the mounts under a quasi-static load are developed when torque struts exist in a PMS. An example is given of the calculation and comparison of the displacements of the powertrain’s CG and mounts in a generic PMS including a torque strut using both the method proposed in this paper and the conventional method published in the referenced papers.

Optimization method for powertrain mounting systems with uncertain parameters

This paper presents an interval optimization method to improve the design robustness of the decoupling layout and frequency allocation of powertrain mounting systems (PMSs). The effects of the uncertainties or variations of the powertrain inertia properties and design parameters on the optimization results are considered in the optimization process. Generally, it is difficult and costly to determine statistical information with sufficient precision for uncertain parameters, so here interval numbers are used to describe the uncertain parameters and only the bounds of them are required. Robustness indices of interval reliability and interval possibility degree are suggested for characterizing the robustness of PMS decoupling layout and frequency allocation respectively. The interval optimization problem is transformed to an equivalent deterministic one based on the robustness indices. The optimization results of a PMS show that the interval optimization method can significantly increase the robustness of the frequency allocation, especially in vertical and pitch directions. This will decrease the possibility of resonance between the powertrain and other parts, such as the wheel, car body, and frame. In contrast to the deterministic optimization method, although the decoupling ratios obtained by the proposed method decrease slightly, the interval optimization results can meet the decoupling layout requirement from the viewpoint of engineering.

Multiobjective Optimization of Hybrid Electrical Vehicle Powertrain Mounting System Using Hybrid Genetic Algorithm

Powertrain mounting system of a Hybrid Electrical Vehicle (HEV) is analyzed and researched, the expression of energy distribution matrix and that of mounting reaction force are derived, and mathematical model of the system is established in Matlab. Correctness of the model established is tested and verified through model establishing for simulation and calculation in ADAMS. Features of Hybrid Genetic Algorithm (HGA) for multiobjective optimization are analyzed and researched, model for calculation of multiobjective optimization using Hybrid Genetic Algorithm is established, targets for optimization of the system are determined, and optimization is executed based on the mounting stiffness parameters. The result that the system is optimized apparently by Hybrid Genetic Algorithm is revealed through contrast of the energy distribution matrix and mounting reaction force of pre and post-optimization.

Optimal Design Method of Power-train Mounting System for Generalized Force Transmissibility Reduction

Generalized force transmissibility(GFT) and sum of GFT integrals of power-train mounts are defined,which are appropriate to be taken as vibration isolation index of power-train mounting system.A design optimization approach for power-train mounting system is proposed,with many design variables,several constraints of rigid-body modal frequencies and an objective of minimizing the sum of GFT integrals.As an example,a power-train mounting system of a coach is optimized with the approach,and important design parameters,such as coordinates,angles and spring rates of power-train mounts,are optimized.As a result,the GFTs,the frequency ratio and dynamic force transmissibility are improved,thus certifying feasibility and effectiveness of this optimizatioin approach.

Theoretical and Experimental Study on the Structure and Vibration Isolation Characteristics of a Hydraulic Engine Mount

Hydraulic engine mounts (HEMs) are important vibration isolation parts in vehicle powertrain mounting systems, and the structural parameters of HEMs are the main factors which determine their vibration isolation characteristics. It is of great significance to discover the influences of the structure parameters on their vibration isolation characteristics in the design and study of HEMs. Firstly, the vibration isolation characteristics of HEMs are analyzed theoretically using a simplified lumped parameter (LP) model. Secondly, the HEMs with different rubber materials, lengths and cross-sectional areas of the inertia tracks are designed and manufactured, and their frequency response characteristics are investigated by experimental and analytical methods. Finally, the influences of these structural parameters on the vibration isolation characteristics of HEMs are educed. The analytical methods and conclusions are instructive for the design and tuning of the vibration isolation characteristics of HEMs.

Robust optimization design method for powertrain mounting systems based on six sigma quality control criteria

This paper presents a robust optimization design method based on Six Sigma quality control criteria to improve the design of a powertrain mounting system (PMS). The powertrain is modeled as a rigid body having six degrees of freedom (DOF) connected to a rigid base by four rubber mounts, and each mount is simplified as a three-dimensional spring-damper element in its local coordinate system (LCS). The calculation method based on energy decoupling is used to estimate the decoupling ratios of a PMS. The location and static stiffness of each mount and the orientations of the two anti-torsion mounts are selected as uncertain design variables, and the nominal values of these design variables are optimized to obtain a robust Six Sigma design for a PMS. The uncertain design variables are characterized by a perturbation or percent variation around their nominal values. The generalized reduced gradient (LSGRG2) optimization method is employed to solve the robust optimization problem, and a second-order Taylor series expansion is used to estimate the statistical properties of the performance constraints and objectives. The optimization results show that the robust design ensures good robustness or high reliability for the natural frequencies, decoupling ratios, and frequency separation constraints of a PMS.

Integration of experiment and hydrostatic fluid-structure finite element analysis into dynamic characteristic prediction of a hydraulically damped rubber mount

Hydraulically damped rubber mount (HDM) can effectively attenuate vibrations transmitted between an automotive powertrain and body/chassis and reduce interior noise in the car compartment. Predicting the dynamic characteristics of a HDM faces challenges due to fluid-structure interactions between the rubber spring and fluid in the chambers, nonlinear material properties of the rubber parts and turbulent flow in the chambers and fluid track linking chambers. In this paper, an experimental analysis and hydrostatic finite element (FE) modeling technique are integrated in a numerical simulation approach to modeling the dynamic characteristics of a HDM with a lumped-parameter HDM model. The dynamic characteristics of a typical HDM with a fixed decoupler are predicted and compared with experimental results, which verify the effectiveness of the proposed approach. Moreover, a parametric effect analysis is performed to demonstrate parameter influence on dynamic characteristic, which provides a concise design guideline for the parameter adjustments necessary for a HDM to meet the vibration isolation requirements of a powertrain mount system.

Nonlinear Dynamic Characteristics of Powertrain Mounting System with Piecewise-linearity Rubber Mounts of Fuel Cell Vehicle

An analysis method based on averaging method is built for the nonlinear oscillation characterization of mounting system dynamics of fuel cell vehicle powertrain.In the analysis,a two degree of freedom vibration model with piecewise-linearity rubber mounts is established,and the amplitude-frequency function is formulized by using averaging method.Based on the mathematical formula,the nonlinear resonance characteristics and its sensitivity to system parameters,including powertrain mass,piece-wise rubber mount stiffness,damping coefficient and excitation amplitude,are numerically analyzed.The simulation results show that the averaging method can be applied to the nonlinear powertrain mount system vibration analysis,and that the sensitivity analysis results are applicable to the powertrain mount system design and optimization.

Vibration Analysis of Powertrain Mounting System with a Combination of Active and Passive Isolators with Spectrally-varying Properties

Vibration Analysis of Powertrain Mounting System with a Combination of Active and Passive Isolators with Spectrally-varying Properties

Engine mounts and powertrain mounting systems: a review

The developments, performances and applications of mounts that from conventional rubber mount to active mount are reviewed and discussed. In the design of a Powertrain Mounting System (PMS), the layouts for a powertrain and the mounts should meet some generally used layouts that are discussed in this paper. Also the natural optimisation method, motion control strategies and calculation methods for vibration control and isolation in design a PMS are reviewed and discussed. It is concluded that the optimisation technology in determining the stiffness in nonlinear section and tuning points in the force vs. displacement curve of a mount should be developed and the application of Trans Path Analysis (TPA) and theory of power flow should be enhanced. The bracket of a mount has great influenance on the isolation effects of a PMS, and should be designed carefully.

The modelling and road simulation test of a hydraulic engine mount

Hydraulic engine mounts (HEMs) are important vibration isolation components in vehicle powertrain mounting systems. The vibration isolation characteristics of HEMs may greatly affect the noise, vibration and harshness (NVH) properties of vehicles. Therefore, it has great significance to acquire the vibration isolation characteristics of HEMs. A simplified lumped model of a HEM and a new method to identify the parameters in this model are proposed in this study. The vibration isolation characteristics of the HEM can be easily obtained by this model and parameter identification method. Dynamic characteristic experiments and road simulation tests of the HEM are also done in this study. The results imply the simulation vibration isolation characteristics of the HEM by modelling agree well with the experimental results and the test fatigue life of the HEM satisfies with the design requirement. This parameter identification method is instructive for the design and tuning of the vibration isolation characteristics of HEMs.

Modelling of dynamic performances for Hydraulic Engine Mounts using fractional derivative and optimisation of Powertrain Mounting Systems

A Hydraulic Engine Mount (HEM) is an advanced passive vibration isolator, and is now widely used in automotive Powertrain Mounting System (PMS). A version of fractional derivative model characterised by five parameters is presented to describe the dynamic properties of an HEM. A model for a PMS is established, and formulae for estimating the dynamic displacement of the powertrain Centre of Gravity (CG) and the reaction forces of a mount under different loads are presented. An optimisation procedure is developed for reducing resonance peaks of a powertrain CG and the reaction forces at mounts. A generic PMS with two rubber mounts and two HEMs is used to validate the optimisation method.

Dynamic characteristic simulation of hydraulically damped rubber mount based on finite element parameter estimation for vehicle powertrain

Performance analysis of the dynamic characteristics of hydraulically damped rubber mounts (HDM) faces challenges owing to the fluid-structure interaction between rubber springs and fluid in chambers, non-linear material properties of rubber parts and turbulent flow in chambers and fluid track linking chambers. In this article, finite element-based parameter estimation and lumped-parameter modelling of HDM are developed for numerical simulation of dynamic characteristic of HDM. Dynamic characteristics of a typical HDM with fixed decoupler are predicted and compared with experimental results, which verify the effectiveness of the proposed approach. The presented approach provides design guidelines for HDM to meet vibration isolation requirements of a powertrain mount system through parameter adjustment.

Optimization of mechanical structures under special consideration of materials

AbstractStructural and Mechanical Optimization Problems are well distributed and described in literature. A high number of applications from different industry fields are publicated. Due to increasing demands for performance improvement together with reduced weight and costs the specific consideration of material laws and uncertainties into optimization problems in mechanical engineering is required. This paper presents an overview about Stochastic Structural Optimization as far as required to consider specific material laws. The application of structural stochastic optimization with specific material laws is illustrated at different test and industrial examples:• Ten‐Bar System as standard test application with elastic material law and scattering material parameters• Ceramic Mirror with brittle ceramic materials• Powertrain Mounting System with nonlinear rubber material• Large scale Vehicle Body Structure with plastic material. Here the application will be presented and one of the commercial software systems. The details of this example will be publicated in the future. The numerical evaluation of this example is very expensive and time consuming. This is the one reason why stochastic optimization is not well distributed already.The presented examples are results of different projects the authors has worked at in the last 12 years at university and industry. About a decade ago stochastic optimization routines were still programmed in small working groups at universities. To increase the application to different industry branches, commercial software has to be used. There are a number of software packages on the market claiming the capability of stochastic optimization as well. In the next time these packages will be tested at different applications. This will be part of the planned publication in the future. The Vehicle Body Structure example in this paper will outline the task without going into the details. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Strategies and Calculation Methods for Automotive Powertrain Motion Control under Quasi-Static Loads

The mount in an automotive powertrain mounting system (PMS) is modelled as three-dimensional springs in its local coordinate system (LCS). The relation of the force versus the displacement of each spring is usually non-linear and is simplified as piecewise linear at five ranges in the present paper. The equation for solving displacements of the powertrain centre of gravity is presented, and an iterative algorithm is developed to obtain the displacements. The methods for estimating the displacements and the reaction forces of a mount are also proposed. The widely used strategies for the powertrain motion control under static or quasi-static loads are suggested. The calculation method is validated in designing a PMS with four mounts. The present paper adds significantly to other publications on this subject because it develops a calculation method for the design of the powertrain motion control under quasi-static loads.

An integrated characteristic simulation method for hydraulically damped rubber mount of vehicle engine

Hydraulically Damped Rubber Mount (HDM) is widely equipped in vehicle powertrain mounting system and plays an important role in noise, vibration and harshness (NVH) control of vehicle. It is necessary that static and dynamic characteristics of HDM and its effectiveness on vibration isolation of powertrain system are predicted at design and development stage. In this paper, a kind of graphic HDM modeling method integrating with parameter identifications obtained from finite element (FE) analysis and experimental analysis is investigated to predict performance of HDM. The fluid–structure interactions in HDM are explored by predictions of volumetric elasticity and equivalent piston area of fluid chamber using a kind of hydrostatic fluid–structure FE method in commercial code of ABAQUS. Predications of static elasticity and dynamic characteristics and frequency response analysis of a typical HDM with fixed-decoupler verify the effectiveness of the proposed method. This research helps automotive engineers to enhance computer-aided system technology in design and development of HDM and powertrain mounting system.