Hydraulic Mount Research Articles

Fractional-Order Least-Mean-Square-Based Active Control for an Electro–Hydraulic Composite Engine Mounts

For the vibration of automobile powertrain, this paper designs electro–hydraulic composite engine mounts. Subsequently, the dynamic characteristics of the hydraulic mount and the electromagnetic actuator were analyzed and experimentally studied separately. Due to the strong nonlinearity of the hybrid electromechanical engine mount, a Fractional-Order Least-Mean-Square (FGO-LMS) algorithm was proposed to model its secondary path identification. To validate the vibration reduction effect, a rapid control prototype test platform was established, and vibration active control experiments were conducted based on the Multiple–Input Multiple–Output Filter-x Least-Mean-Square (MIMO-FxLMS) algorithm. The results indicate that, under various operating conditions, the vibration transmitted to the chassis from the powertrain was significantly suppressed.

New bell plate controlled multi-inertia channel magnetorheological fluid mount wide frequency vibration isolation control study

This paper introduces a novel type of magnetorheological fluid (MRF) mount designed to achieve wide-frequency vibration isolation for engines. While previous studies have explored vibration isolation using hydraulic mounts, there has been limited research on achieving wideband isolation with MRF mounts. Consequently, this paper presents an innovative MRF mount structure and investigates wideband vibration isolation control for engines. Initially, experiments with a multi-channel MRF damper validate the switchable operation of controllable channels. A novel controllable multi-inertia channel MRF mount system is proposed, aligning the working mode of controllable inertia channels with that of the MRF damper. The lumped parameter method is employed to derive the mathematical model of the MRF mount, and its high and low-frequency dynamic characteristics are thoroughly examined. Subsequently, a real-time multi-island genetic algorithm-optimized controller is developed to investigate wideband vibration isolation within the MRF mount system. The findings indicate that: (1) The MRF mount demonstrates adjustable low-frequency dynamic stiffness and loss angle within the frequency range of f = 0–50 Hz. In the frequency range of f = 50–100 Hz, the mount achieves its lowest dynamic stiffness value, effectively addressing the issue of high-frequency stiffening. (2) The real-time multi-island genetic optimized controller exhibits superior vibration isolation performance compared to traditional sky-hook control and hybrid sky-hook control methods, achieving optimal vibration isolation for the mount.

Effect of bell plate structure on high- and low-frequency characteristics of hydraulic mount

Effect of bell plate structure on high- and low-frequency characteristics of hydraulic mount

Time domain response analysis of multi-flow channel hydraulic mount

In order to analyze the effect of the combination of long and short inertia channels and orifice flow channels on the time domain response of hydraulic mounts. Firstly, six hydraulic mounts with different combinations of inertia channels and orifice flow channels are proposed. And then, the transfer functions of dynamic stiffness and upper chamber pressure for six structures of hydraulic mounts are derived using the lumped parameter method. Next, the time domain analytic formulas for the transfer force and upper chamber pressure for six structural hydraulic mounts under steady-state excitation and step excitation are obtained using the convolution method. Finally, the analytical formula is compared with the hydraulic mount’s model built by AMEsim; Meanwhile, the effects of inertia terms of inertia channels, damping, and damping of orifice flow channels on hydraulic mounts transfer forces are analyzed; Analyze the effect of transfer force variation and excitation amplitude on hydraulic mounts damping for different configurations of structures. Research shows that inertia channels and orifice flow channels directly affect the low-frequency dynamic characteristics of hydraulic mounts. At the same time, the effective damping height of the hydraulic mounts depends on the excitation amplitude.

Analysis of the influence of the interaction between decoupled membrane channels and inertial channels on the mount' characteristics

In order to study the effect of the interaction between different inertial channels and decoupler membrane channels on the hydraulic mount characteristic. Firstly, the effect of the single inertia channel and decoupler membrane channel interaction on the hydraulic mount characteristic is analyzed. Secondly, a multi-inertia channel hydraulic mount model with nine structures and four combination schemes is proposed. Among them, the mount's structure includes long inertia channels, short inertia channels, different inertia channel cross-sectional areas, and the number of inertia channels. And then, the number of inertia channels, the cross-sectional area, and the interaction between long and short inertia channels and decoupler membrane channels are analyzed for their effects on the hydraulic mount characteristics. Finally, the effect of the interaction between the inertial and decoupler membrane channels on the time-domain characteristics of the hydraulic mount at different excitation amplitudes. The results show that the number of inertia channels, cross-sectional area, and the interaction between the number of long and short inertia channels and decoupler membrane channels directly affect the vibration isolation performance of hydraulic mounts at high and low frequencies.

Influence of the Temperature of Magnetorheological Fluid on Vibrational Damping by Hydraulic Mounts

Influence of the Temperature of Magnetorheological Fluid on Vibrational Damping by Hydraulic Mounts

Indirect force estimation method under spectrally varying and amplitude-sensitive conditions by estimating the effective fluid path parameter

Indirect methods to estimate the force transmitted from the source to the receiver have been investigated using various approaches to increase accuracy and overcome discrepancies, especially when the measurements are conducted in situ. To implement the indirect force estimation techniques in situ, developing an accurate measurement method and establishing reasonable system models always matter when the force estimations involve nonlinear internal forces such as the upper chamber pressures of the hydraulic mount system. Based on prior research conducted on force estimation in a nonlinear hydraulic mount, a simplified reverse-path spectral method is proposed in this study for estimating the force transmitted from the driving point to the ground by focusing on one effective fluid path parameter. To achieve the purpose of this study, two interfacial force datasets from the non-resonant test were first captured along with spectrally varying and amplitude-sensitive conditions. Second, two different path forces were determined from the rubber and hydraulic paths, and the effective fluid path parameter (EFP) was estimated from the hydraulic path force. The employment of the EFP contributes to estimating the effective internal properties, which show better correlations with the measurements than the estimated results from prior studies. Thus, the current work, performed by focusing on the EFP, successfully suggests a simplified yet efficient way to develop an indirect force estimation method in a nonlinear hydraulic mount as a dynamic load sensing system.

Influence of temperature of a magnetorheological fluid on damping of vibration disturbances by hydraulic mounts

The issues of dynamic stiffness coefficient control and increasing the damping ability of magnetorheological vibration mounts (MR-hydromounts) are considered. It is shown that in order to reduce the dynamic stiffness coefficient and increase the damping ability of the MR-hydromount it is necessary to reduce the coefficient of hydraulic resistance of the working magnetorheological fluid flow, which can only be achieved by increasing the number of throttle channels in the baffle plate. Calculation of the dynamic stiffness coefficient of the MR-hydromount depending on the magnetic field strength in the magnetorheological fluid and its heating temperature is presented. Keywords: inertial transformer, magnetorheological transformer, magnetorheological fluid, hydromount, working fluid, heating temperature, dynamic stiffness coefficient. gord349@mail.ru, acidwolfvx@rambler.ru, oxulkovs@mail.ru, aplehov@mail.ru, dm_titov@list.ru

Research on the vibration isolation performance of low-frequency hydraulic engine mount

This paper aims to study the influence of decoupler membranes on the vibration isolation performance of hydraulic mount under low-frequency excitation. Firstly, the mathematical model of the hydraulic mount is constructed using the lumped parameters and the accuracy of the mathematical model is confirmed. Secondly, the influence of the dynamic characteristics and flow rate of the hydraulic mount under different excitation amplitudes and excitation frequencies is analysed. Finally, the hydraulic mount system of the 1/4 car model is built to analyse the effect of with or without decoupler membrane channels on the vibration isolation performance of the system from sinusoidal excitation, random road spectrum, and different engine speeds. The results of the study show that the decoupler membrane directly affects the hydraulic mount in low frequency vibration isolation performance.

Method of improving the soil compactor's ride quality based on the optimal negative stiffness structure

A new driver's seat suspension designed by the negative-stiffness-structure (NSS) and cab's isolation used by the hydraulic mounts are proposed to enhance the soil compactor's ride quality. A nonlinear vehicle dynamics model that considers the interaction between the wheel/drum and deformable terrains is established to evaluate the NSS's performance. Based on the genetic algorithm, NSS's parameters are optimised to further improve ride quality. The ride quality is evaluated through the displacement and acceleration of the seat and cab in the frequency and time domains. The research results are also verified via the experiment. The results show that the root-mean-square (RMS) and power-spectral-density of the seat and cab accelerations with the optimal NSS are strongly reduced in comparison without NSS. Especially, the RMS seat's acceleration is markedly attenuated by 67.54% under the vehicle working condition. Therefore, the optimal NSS applied on off-road vehicle's seat suspension could enhance the ride quality.

Frequency domain characteristics of decoupler membrane hydraulic mounts by different combinations of inertial channels and orifice flow channels

Frequency domain characteristics of decoupler membrane hydraulic mounts by different combinations of inertial channels and orifice flow channels

Frequency domain characteristics of decoupler membrane hydraulic mounts by different combinations of inertial channels and orifice flow channels

Frequency domain characteristics of decoupler membrane hydraulic mounts by different combinations of inertial channels and orifice flow channels

Analysis of low frequency response characteristics of multi-inertia channel hydraulic mounts

Analysis of low frequency response characteristics of multi-inertia channel hydraulic mounts

Analysis of low frequency response characteristics of multi-inertia channel hydraulic mounts

Analysis of low frequency response characteristics of multi-inertia channel hydraulic mounts

Enhancing the ride comfort of off-road vibratory rollers with seat suspension using optimal quasi-zero stiffness

The research proposes a new design of the seat suspension equipped with the quasi-zero stiffness (QZS) and hydraulic mount (HM) of the cab isolation system to improve the ride comfort of off-road vibratory rollers. To assess the ride comfort of the vehicle using the QZS and the HM, a dynamic model of the off-road vibratory roller is built and researched under various interactions of the drum/wheel and off-road terrain. Based on the multi-objective genetic algorithms, the design parameters of the QZS are also optimized to further enhance the vehicle’s ride comfort. The QZS optimized (QZSO)’s efficiency and the ride comfort of the off-road vibratory roller are analyzed based on the indexes of the seat displacement and acceleration; and the cab’s pitching and rolling acceleration. The experimental investigation is then carried out to verify the accuracy of the mathematical model and research result. The investigation result indicates that with the QZSO applied on the seat isolation, the Root-Mean-Square and Power-Spectral-Density of the acceleration responses of the seat and cab are greatly decreased compared to the seat isolation without the QZS in both the time and frequency regions. Particularly, the Root-Mean-Square acceleration of the seat is remarkably decreased by 61.7% when the vehicle is moving and 67.5% when the vehicle is working. Consequently, this research can provide a valuable reference and knowledge for the application of the QZSO on the driver’s seat suspension of off-road vehicles to optimize ride comfort.

Identification of Dynamic Parameters and Frequency Response Properties of Active Hydraulic Mount with Oscillating Coil Actuator: Theory and Experiment

Active hydraulic mounts (AHMs) provide an effective solution for refining ride comfort noise and vibration in passenger cars. AHMs with inertia tracks, decoupler membranes, and oscillating coil actuators (AHM-IT-DM-OCAs) have been extensively studied owing to their compact structures and strong damping characteristics in the low-frequency band. This study focuses on the full parameter identification based on the distinct features of external dynamics, which can be used to obtain an accurate and reliable estimate of the transfer functions required for active control algorithms. A lumped parameter model was established for the AHM-IT-DM-OCAs, and the analytical frequency bands were defined by the two resonance frequencies of the fluid channel and actuator mover. Methods for nonlinear model simplification were proposed in different bands and verified theoretically. Based on the simplified models, the distinct features of the active and passive dynamics are successively revealed, which include three resonances and seven horizontal segments. Subsequently, a series of experimental studies on the distinct features were carried out, which agreed well with the theoretical results. However, owing to the limitations of the test equipment and fixture modalities, only the distinct features of one fixed point, two resonance peaks, and three horizontal segments can be used for parameter identification. Based on the validated distinct features, a procedure for full parameter identification is proposed, and all six key parameters are identified. The obtained results showed good consistency and rationality, indicating that this approach can be used for the transfer function estimation of the primary and secondary paths of the AHM-IT-DM-OCAs.

Controlling isolation system of initial combustion engines

To evaluate the effect of the engine vibration on the vehicle's ride comfort and improve the vehicle's ride comfort, three types of engine’s isolation systems including the traditional rubber mount (TRM), hydraulic mount (HM), and semi-active HM controlled by the PID control (SHM) are proposed. A dynamic model of the inline 4-cylinder engine is established to determine the excitation force of the engine. By the combination of the random excitation of the vehicle floor affecting the engine isolation system, the isolating performance of the TRM, HM, and HM is then simulated and evaluated on isolating the engine vibration and improving the vehicle’s ride comfort. Both the root mean square (RMS) values of the engine acceleration response (aRMSe) and isolation force (FRMS) of engine isolation systems are given as the objective functions. The research results show that the engine vibration combined with the excitation of the road surface roughness significantly affects the vehicle’s ride comfort. By using the SHM, both the engine acceleration and isolation force are significantly reduced in comparison with the TRM. Especially, the values of the aRMSe and FRMS are remarkably decreased by 9.32 % and 9.69 % in comparison with the TRM. Thus, to improve the vehicle's ride comfort and reduce the effect of the engine's vibration on the ride comfort, the engine isolation system used by the TRM needs to be replaced by using the SHM.

Influence of Working Fluid in the Throttle Channels of Hydraulic Mounts on the Damping Properties

Influence of Working Fluid in the Throttle Channels of Hydraulic Mounts on the Damping Properties

Modeling Method of Dynamic Characteristics of Hydraulic Damping Rubber Isolator

<div class="section abstract"><div class="htmlview paragraph">The dynamic characteristics of hydraulic damping rubber isolators (such as hydraulic bushing and hydraulic mount) are related to excitation amplitude and frequency. Based on the lumped parameter model of hydraulic damping rubber isolator, a unified linear model of complex stiffness is derived and its deficiency is pointed out. Based on the derived linear model, this paper considers the nonlinear damping of inertia channel and the nonlinear stiffness of the upper chamber of the hydraulic damping rubber isolator, so as to establish a new nonlinear model, which can reflect the amplitude and frequency dependence of the dynamic characteristics of the hydraulic damping rubber isolator. Finally, the nonlinear model is used to analyze the dynamic response of hydraulic damping rubber isolator under harmonic excitation and random excitation respectively, and the results are compared with the test results. The results show that the proposed model can characterize the amplitude and frequency dependence of the dynamic characteristics of the hydraulic damping rubber isolator, and can accurately calculate the dynamic response of the hydraulic damping rubber isolator under harmonic excitation and random excitation.</div></div>

Improving the vibratory roller's ride comfort under off-road soil grounds by applying the seat's negative-stiffness elements

This study proposes the cab's hydraulic mount (HM) and seat's negative-stiffness elements (NSE) to reduce the cab shaking and improve the ride comfort of the vibratory rollers. A vehicle dynamic model is built to assess the vehicle's ride comfort under deformable soil grounds. The indexes of the root-mean-square (r•m•s) seat displacement (Zw1), r•m•s seat acceleration (aw1), and r•m•s cab pitching acceleration (awϕ2) are selected to assess the ride comfort. The study results indicate that the seat's ride comfort and cab's pitch angle are greatly improved by using the NSE and HM under various working conditions. Especially, the Zw1, aw1, and awϕ2 are remarkably reduced by 36.4%, 82.4%, and 50.9% in comparison without the NSE and HM when the vehicle is travelling on deformable soil grounds, respectively. Consequently, the application of the NSE on the seat's suspension of vibratory rollers or other vehicles can further enhance the driver's ride comfort and health.