Dual Mass Flywheel Research Articles

Influence of the driving environment on the dynamic characteristics of a DCT vehicle starting considering the longitudinal and vertical coupling model

The most significant external excitation affecting the dynamic characteristics of a vehicle is its driving environment. This type of excitation leads to issues such as slow initial response during starting, significant vibrations in the transmission system, and overall performance instability. A longitudinal–vertical coupled dynamics model has been developed to analyse the impact of driving conditions on the dynamic characteristics of vehicles with Dual-Clutch Transmission (DCT) during starting. This model takes into account factors such as the engine’s harmonic torque, the time-varying meshing stiffness of the gear system, the nonlinear torsional behaviour of the dual-mass flywheel, the deformation and torsion of the powertrain mounts, tire deformation, and random road excitations. Utilizing the established coupled model for DCT vehicle transmission systems, the impact of varying road roughness, adhesion coefficients, and road slope on the dynamic performance of DCT vehicles. To verify the accuracy of the simulation results of the influence of the driving environment on the dynamic characteristics of the DCT vehicle starting process, the experimental and simulation results of the influence of the driving environment on the vehicle dynamic characteristics of flat road surfaces, B-level uneven road surfaces, wet road surfaces, and 10% road slopes were compared. The overall trend of the simulation results of the clutch master and slave end speeds, vehicle longitudinal and vertical impact degrees, etc., was in good agreement with the experimental results, confirming the accuracy of the established DCT vehicle transmission system coupling dynamic model.

Design of the Torsional Properties Measurement Stand for Rubber-Metal Elements in Motor Vehicles

Abstract This paper describes design and application of a torsional property measurement stand used for analyzing rubber-metal components. The paper covers mechanical, electrical and control systems. Design of the stand takes into consideration reusing existing components, that come from a measuring stand that was used for analyzing automotive dual-mass flywheels. Paper covers initial design proposal as well as final design in CAD model form and the finished assembled stand. A Section of this paper is dedicated to describing the components and software used to control the stand and collect data from sensor. Programming of the excitation movement cycle in TIA-Portal software is also covered in this section. Lastly it covers experimental analysis. Our findings and evaluation of the machine itself is found in the conclusion chapter.

Electromagnetic Field and Variable Inertia Analysis of a Dual Mass Flywheel Based on Electromagnetic Control

The moment of inertia of the primary flywheel and the secondary flywheel in a dual mass flywheel (DMF) directly affects the vibration damping performance in an automotive driveline. To enable better minimization of vibration and noise by changing the moment of inertia of the DMF to adjust the frequency characteristics of the automotive driveline, a new variable inertia DMF structure is proposed by introducing electromagnetic devices. The finite element simulation model of the electromagnetic field of an electromagnetic device is established, the electromagnetic field characteristics in the structure are analyzed, and the variation in the electromagnetic force under different air gaps and current conditions is obtained. The electromagnetic force test system of the electromagnetic device is constructed, and the validity of the finite element simulation analysis of the electromagnetic field of the electromagnetic device is verified. A mechanical model of the electromagnetic device is established to analyze the characteristics of the displacement of the moving mass in the structure as well as the variation in the moment of inertia of the DMF at different rotational speeds and currents. The maximum adjustable proportion of its moment of inertia can reach 15.07%. A torsional model of the automotive driveline is established to analyze the effect of variable inertia DMF on the resonance frequency of the system under different currents. The results show that the electromagnetic device introduced in the DMF can realize the active adjustment of the moment of inertia and enable the resonance frequency to decrease with increasing rotational speed, which expands the idea of optimizing the vibration damping performance of the DMF and provides a reference for better control of the torsional vibration of the automobile or other mechanical transmission systems.

Effect of AVL-based time-domain analysis on torsional vibration of engine shafting

The torsional vibration of the shaft system in hybrid car engines has a significant impact on the overall performance of the vehicle, and it is more complex in hybrid cars compared to traditional cars. Traditional methods for torsional vibration analysis of shaft systems have significant limitations and cannot handle nonlinear and transient problems. To explore the torsional vibration characteristics of hybrid vehicle shaft systems, a simplified engine shaft system torsional vibration equivalent model is innovatively constructed. In addition, a method for quickly determining the confidence level of the torsional vibration equivalent model is proposed. Additionally, the transient dynamic characteristics of a multi-body dynamics model containing a dual mass flywheel are analyzed in depth using the time-domain solver of AVL-exact PU. The results demonstrated that the simulation of 4th and 6th harmonics resonated at critical speeds of 4,195 rpm and 2,771 rpm, respectively, with angular displacement amplitudes of 0.141 deg and 0.047 deg. In fact, resonance was measured at 4,250 rpm and 3,040 rpm, with amplitudes of 0.14 deg and 0.052 deg. These two were basically consistent in key parameters. When the shaft model was started under operating conditions, the amplitudes of harmonics 1, 2, and 4 were basically consistent below 750 rpm, and there were slight differences after 750 rpm. Therefore, the AVL-based engine torsional vibration simulation model constructed has high credibility.

Experimental evaluation of the torsional vibration characteristics of a dual-mass flywheel based on multi-condition and multi-index methods

Experimental evaluation of the torsional vibration characteristics of a dual-mass flywheel based on multi-condition and multi-index methods

An Innovative Mechanical Approach to Mitigating Torque Fluctuations in IC Engines during Idle Operation

Internal combustion engines have been a major contributor to air pollution. Replacing these engines with electric propulsion systems presents significant challenges due to different countries’ needs and limitations. An active, purely mechanical solution to the problem of irregular torque production in an alternative internal combustion engine is proposed. This solution uses an actuator built on a camshaft and a spring, which stores and returns energy during the engine operating cycle, allowing torque production to be normalized, avoiding heavy flywheels. Designed for control throughout the engine’s duty cycle, this system incorporates a cam profile and a spring mechanism. The spring captures energy during the expansion stroke, which is then released to the engine during the intake and compression strokes. Simple, lightweight, and efficient, this system ensures smoother and more consistent engine operations. It presents a viable alternative to the heavy and problematic dual-mass flywheels that were introduced in the 1980s and are still in use. This innovative approach could significantly enhance the performance and reliability of alternative internal combustion engines without notable energy losses.

Research on Nonlinear Vibration of Dual Mass Flywheel Considering Piecewise Linear Stiffness and Damping

Nonlinear torsional vibration differential equation of the nested arc-shaped short spring dual mass flywheel (DMF) is established, considering the piecewise linear stiffness and damping of the spring. The first-order approximate analytical solution under sinusoidal excitation and the amplitude–frequency characteristic function are obtained by means of the average method which verified by the Runge–Kutta (R–K) method. The effects of the parameters of input excitation, inertia, and piecewise linear stiffness and damping of DMF on the resonant amplitude, resonant frequency band, and equivalent linear natural frequency of the system are analyzed. The results show that the amplitude–frequency characteristic curve bending and jumping with the changes of excitation frequency and the peak of resonant amplitude can be obviously reduced by increasing the inertia of the primary flywheel and decreasing the inertia of the secondary flywheel. The complex nonlinear dynamic phenomena such as Period 1, quasi-periodic, and chaos are obtained by analyzing the forced vibration response under the different excitation frequencies.

The influence of friction between elements of dual-mass flywheel on oscillatory phenomena in a car transmission

Automobile manufacturers, when designing new cars, are increasingly faced with the need to reduce the weight of components in order to achieve the required level of fuel consumption and environmental standards. As a result, internal combustion engines (ICEs) with a small number of cylinders are designed and manufactured, which allows to achieve an increase in output power due to increased pressure in the cylinder and more efficient fuel combustion. As a result of this, torsional vibrations occur on the crankshaft, which are transmitted and negatively affect the transmission, causing it to fail prematurely. The damping properties of dual-mass flywheel (DMF) in a straight line depend on their structure and design parameters. All modern DMF contain a certain amount of thick lubricant, which in one way or another improves its characteristics. But in addition to parts, flywheels that constantly work in an environment with lubricant, there are also elements between which dry friction occurs, which also affects the damping characteristics of the flywheel. Therefore, it can be assumed that its presence affects the elastic-damping properties of the DMF. The purpose of the work is to develop simulation models and study the effect of friction between DMF elements on oscillatory processes in the car transmission and to develop recommendations for reducing the load on DMF elements and transmission links. The effect of dry and viscous friction between the elements of a DMF on the damping of oscillations in the links of its elastic-damping system and the drive links of the car was studied. It is shown that an increase in the coefficient of dry friction between DMF elements from 0 to 0.3 does not provide a noticeable damping of oscillations in the drive links and tension in the DMF springs. The coefficient of viscous friction between the links of the DMF has a significant influence on the amount of tension in the springs of the DMF. To increase the resource of the DMF, it is advisable to install separators made of polymer material between the elastic links with a small coefficient of friction between it and the steel body of the DMF.

Nonlinear analysis of torsional vibrations of dual mass flywheel in a three-cylinder engine

Torsional vibration of the power transmission system is one of the main factors which affects ride comfort and fatigue of the driveline components. These vibrations are caused by periodic changes in the gas pressure and inertial forces. To reduce these vibrations, dual mass flywheels (DMF) are used in some vehicles. DMFs are usually modelled as two disks connected with linear springs. However large rotation angle in DMFs can invalidate linear assumption. In this research, torsional vibration of a three-cylinder engine with nonlinear DMF is investigated and an analytical solution is obtained for the governing nonlinear equations of torsional vibrations under real engine torsional excitation for the first time. It should be noted that in the previous works, the torsional vibration equations of the DMF had been solved numerically. Analytical solution helps to study the effect of design parameters of DMF more easily. It is shown that the analytical and numerical solutions are well matched in steady-state conditions. Finally, a parametric study is performed and the effects of design parameters on the oscillation amplitude of the engine speed and flywheel output speed are presented.

Analysis of the Influence of a Powertrain Mounting System on a Dual-Clutch Transmission Vehicle under Typical Working Conditions

The unsuitably designed powertrain mount may cause jittering and shrugging during the starting and shifting processes of the vehicle, which seriously affects the comfort of using the vehicle. However, the influence of mounts on vehicles has been neglected in previous studies. In view of the above problems, this study establishes a DCT vehicle coupling dynamic model, considering six degrees of freedom of the powertrain mount and the engine dynamic torque, nonlinear characteristics of a dual-mass flywheel, time-varying stiffness of gear systems, and other factors. Furthermore, the effect of mounts on the longitudinal dynamic characteristics of the vehicle is studied during the starting, shifting, and tip-in/tip-out process. The results show that under typical working conditions, the mount and its stiffness and damping affect the fluctuation frequency and amplitude of the jerk. When the torque of the vehicle transmission system changes greatly, such as under starting and tip-in/tip-out conditions, the mount has a great impact on the dynamic performance of the vehicle. Simultaneously, the engine torque fluctuation can act on the vehicle through the mount, which has an impact on the jerk of the vehicle. A comparison with vehicle test results reveals that the DCT coupling dynamic model can reflect the law of the effect of the mount on the vehicle performance and verify the rationality of the model. Under typical working conditions, when the influence of the mount is not considered in the vehicle dynamic’s modeling, there is a large error of the jerk between the simulation results and the actual situation. The results provide a reference for optimizing the parameters of the mount and improving the dynamic characteristics of DCT vehicles.

Influence of vehicle acceleration intensity on dual-mass flywheel elements and transmission load

Modern high-torque low-speed internal combustion engines (ICEs) generate torsional vibrations close in disturbance frequency to gearboxes natural oscillation frequencies. Effective absorption of such oscillations requires a new torsional vibration damper between the internal combustion engine and gearbox design, which is implemented in the form of a dual-mass flywheel (DMF). One of the main reasons for DMF failure is its spring components destruction. The article develops mathematical and simulation (in MATLAB Simulink environment) model of a car with DMF in the period of starting, which takes into account the dependence of torque and power of the internal combustion engine on the number of the crankshaft revolutions and uneven rotation, car inertial and stiffness parameters, road resistance. It is established that when the car starts in first gear, the maximum load on spring components of DMF and transmission occurs at the initial moment of clutch engagement and exceeds the maximum effective torque of the internal combustion engine 1.6 times, has a pronounced oscillatory character and stabilizes as the car accelerates. With smooth acceleration of a car, when torque of internal combustion engine reaches, but does not exceed its maximum value of 250 N‧m, elastic moment in transmission components is stabilized at 230 N‧m. During intensive acceleration and transition through the extremum on torque curve of internal combustion engine on number of crankshaft revolution, the maximum DMF spring components and transmission load initially doesn’t change significantly, but reduces the duration of oscillatory processes and elastic moment of 160 N·m after attenuation of oscillations. A similar nature of stress changes is observed in the elastic links of DMF, which eventually leads to their fatigue failure and DMF failure. To increase a DMF service life, it is advisable to accelerate a car when moving intensively, bringing a number of revolutions to a value that is located at the extreme of torque of internal combustion engine on its performance characteristic, followed by switching to the next gear.

Parameter influence law analysis and optimal design of a dual mass flywheel

AbstractThe influence of the dynamic parameters of a dual mass flywheel (DMF) on its vibration reduction performance is analyzed, and several optimization algorithms are used to carry out multiobjective DMF optimization design. First, the vehicle powertrain system is modeled according to the parameter configuration of the test vehicle. The accuracy of the model is verified by comparing the simulation data with the test results. Then, the model is used to analyze the influence of the moment of inertia ratio, torsional stiffness, and damping in reducing DMF vibration. The speed fluctuation amplitude at the transmission input shaft and the natural frequency of the vehicle are taken as the optimization objectives. The passive selection method, multiobjective particle swarm optimization, and the nondominated sorting genetic algorithm based on an elite strategy are used to carry out DMF multiobjective optimization design. The advantages and disadvantages of these algorithms are evaluated, and the best optimization algorithm is selected.

Feasibility study of single-mass flywheels with centrifugal pendulum vibration absorbers in vehicles with dual-clutch transmissions

Dual-clutch transmissions (DCTs) are very sensitive to torsional vibration and easily produce rattle noise if a single-mass flywheel (SMF) with a conventional torsional damper or a dual-mass flywheel (DMFW) is used in the vehicle. Only a DMFW combined with a centrifugal pendulum vibration absorber (CPVA) can eliminate rattle problem; however, this solution is expensive. Alternatively, a SMF with a CPVA is proposed to eliminate the DCT rattle issue, which could be a feasible and cost-effective solution free of side effects introduced by DMFWs. The vibration absorption principle of different types of pendulums and the rotor dynamic model are investigated to study the feasibility of a SMF with CPVA in a DCT vehicle. A seven-degree-of-freedom nonlinear lumped torsional vibration model is proposed to evaluate the torsional vibration attenuation performance of different configurations of torsional dampers and CPVAs. As per the model calculation results, the bifilar pendulum features the best attenuation performance compared with the circular and cycloid pendulums. The effect of pendulum parameters on attenuation is studied, and the optimized values are obtained. The SMF and optimized bifilar CPVA combination can satisfy the no-rattle requirements in vehicle relative to the DCT in-vehicle no-rattle threshold. A vehicle assessment on roads using physical pendulum prototypes indicates that the SMF with CPVA can be used as an alternative, cost-effective solution for DCTs, instead of the expensive DMFW with CPVA solution.

Weight-Vibration Pareto Optimization of a Dual Mass Flywheel

Weight-Vibration Pareto Optimization of a Dual Mass Flywheel

Review on Performance of Dual Mass Flywheel over Conventional Flywheel

The Dual Mass Flywheel is used for dampening the oscillations created at the time of working in automotive power transmission system.Dual mass flywheel is a multi-clutch device. The torsional frequency is defined as the rate at which the torsional vibration produced. When the torsional frequency of the crankshaft is equal to the transaxles torsional frequency an effect known as the torsional resonance occurs. When the operating speed of the engine is minimum, vibration occurs due to the torsional resonance and this can be avoided using dual mass flywheel.We explained detailed initial model in the paper. In this mainly having the two arc springs and two masses in the DMF and their nature. By experiment the Dual Mass Flywheel model is compared to convention flywheel. Finally the observation of the engine torque using the DMF is taken. The DMF is manufactured and done experiment or testing to see the results. And then results which came are compare with the conventional flywheel.

Optimization of Dual-Mass Flywheel Parameters Based on a Multicondition Simulation Test

A dual-mass flywheel is an important part of an automobile transmission system whose function is to ensure the smooth transmission of engine power to a gearbox. Vehicle vibration and noise are major indicators of vehicle comfort, while dual-mass flywheel technology can preferably solve the comfort problem. Based on the created torsional vibration model, this paper describes the testing of the torsional characteristics under various conditions with an LMS AMESim simulation. The results show that the noise in the cab is fundamentally below 60 dB. The computational formula for the angular stiffness of an arc coil spring is derived, and then the spring angular stiffness is optimized with arithmetic averaging, which reveals an adjusted angular stiffness of 12.8 Nm/°. Additionally, the requirement for the angular acceleration of the WOT input shaft (i.e., being less than 500 rad/s2) is satisfied for various gears. The test results show that the double-mass flywheel can attain a vibration isolation efficiency of around 85%, which more effectively reduces the transmission vibration and noise and improves the vehicle comfort.

Structural design optimization of the arc spring and dual-mass flywheel integrated with different optimization methods

Abstract This paper is about the structural design optimization of the torsional arc spring and the dual-mass flywheel (DMF) using three different population-based optimization techniques: Particle swarm optimization (PSO), differential evolution (DE), and genetic algorithm (GA). For this purpose, the equations of the motions of the vehicle powertrain are derived and implemented into the dynamic analysis to minimize the vehicle torsional vibrations. The parameters and initial angles of the arc spring are optimized by considering the objective function that is the sum of the maximum acceleration amplitudes of the crankshaft vibrations. The results demonstrated that the proposed design procedure is able to provide a proper arc spring and DMF inertias to reduce the torsional vibration significantly. Moreover, it is indicated that the DE optimization techniques provide best performances than others. Finally, it is also shown that the natural frequencies can be reduced by the DMF and the optimization results are under the idling critical speed of the engine. The obtained results of this paper are of utmost importance for the arc spring manufacturer about the design process considering both DMF and spring parameters simultaneously to minimize torsional vibration of the vehicle powertrain.

A mathematical model for vibration analysis of a parallel hybrid electric bus powertrain

This paper presents a parallel hybrid electric bus equipped with an automated manual transmission (AMT) and a mathematical model of the hybrid powertrain is developed for vibration analysis. The powertrain dynamic model is established by a modular modelling approach. A detailed AMT dynamic model, considering gear time-varying meshing stiffness, shaft elastic deformation, and bearing elastic support, is incorporated into the powertrain dynamic model. The damping and gyroscopic effect of gear-rotor in the AMT are considered as well. The AMT dynamic model is validated by experiment data from the time and frequency domain comparisons. Finally, the parameter analysis of the dual-mass flywheel (DMF) is utilised to illustrate how to use the proposed powertrain dynamic model for vibration reduction. The influence of the DMF parameters on vibration responses of the system with varying engine rotation speed is investigated. This study provides a basis for further vibration control of the hybrid powertrain during the engine driving mode.

Wear Based Lifetime Estimation of a Clutch Facing using Coupled Field Analysis

Repetitive use of the clutch, over a period of time, causes the friction material at the contact surfaces (clutch facing and flywheel/pressure plate) to wear, thus deteriorating its performance and usable life. The working life of a rigid clutch is the limiting factor when it comes to extracting maximum performance from a dual mass flywheel system, which is used in a lot of modern vehicles nowadays to lower fuel consumption and improve ride quality. In this study, we investigate the influence of different groove patterns on wear in rigid clutch facings and estimate their life using a comprehensive finite element model. The wear is calculated and analysed for five different groove patterns across two different inorganic materials, namely FTL180 and TF1600-MC2, using Archard’s Adhesive Wear Model. Coupled multi-physics elements are employed in the analysis to capture the effect of frictional heat generation on wear. We found that the Waffle pattern offered a decrease of 10.4% in volumetric wear loss, a 5.78% decrease in maximum wear thickness and an increase of 11.51% in the average working life is used in city like conditions with frequent engagements. This work sheds light on the impact of groove patterns on clutch facing wear and opens a new path for the design and development of more resilient rigid clutches.

Modeling and Dynamics Analysis of a Dual-Mass Flywheel with the Conformal Contact Action of Friction Damping Ring and Pressure Plate

To study the nonlinear dynamic characteristics of the dual-mass flywheel (DMF) under the conformal contact action between the friction damping ring and primary flywheel pressure plate, the contact action model is established and analyzed based on Winkler model. Through analysis and calculation, the contact deformation, contact pressure at different contact positions, and equivalent torsional contact stiffness are obtained. The nonlinear dynamic analysis model of three-degree-of-freedom (3DOF) which takes the conformal contact into account and two-degree-of-freedom (2DOF) without considering conformal contact is established. The approximate analytical solution of the nonlinear frequency characteristics of the system at steady state is derived. By comparing with the results obtained from numerical method, the theoretical analysis process is proved to be valid. And it is found that the overall amplitude and angular displacement transmissibility of the 3DOF model are smaller than the 2DOF model, especially at resonance frequency. The effects of the friction damping ring moment inertia, stiffness of DMF, and axial friction torque on the frequency characteristics of system and angular displacement transmissibility are analyzed. The forced vibration response analysis of the 3DOF model is conducted, through which the torsional angle variations of the primary flywheel, friction damping ring, and secondary flywheel with time are obtained. The results show that the amplitude of the secondary flywheel is much smaller than that of the primary flywheel, indicating that the DMF has prominent damping performance.