Engine Mounting System Research Articles

Bidirectional active vibration control of two-dimensional structure inspired by automotive engine mounting system

Bidirectional active vibration control of two-dimensional structure inspired by automotive engine mounting system

Bidirectional Multi-Spectral Vibration Control: Insights from Automotive Engine Mounting Systems in Two-Dimensional Structures with a Damaged Vertical Active Element

Active mounting systems have become more prevalent in recent years to effectively mitigate structure-induced vibration across the automobile chassis. This trend is particularly evident in engine mounts. Considerable research has been dedicated to this approach owing to its potential to enhance the quietness and travel comfort of automobiles. However, prior research has concentrated on a limited spectrum of specific vibrations and noise control or has been restricted to vertical vibration control. This article describes the modeling, analysis, and control of a source structure employing a multidirectional active mounting system designed to closely simulate the position and direction of an actual automobile engine mount. A piezoelectric stack actuator is connected in series to an elastic (rubber) mount to form an active mount. The calculation of the secondary force required for each active mount is achieved through the application of harmonic excitation forces. The control signal can also reduce vibrations caused by destructive interference with the input signal. Furthermore, horizontal oscillations can be mitigated by manipulating the parameters via dynamic interconnections of the source structure. We specifically examined the level of vibration reduction performance in the absence of a vertical active element operation and determined whether the control is feasible. Simulation outcomes demonstrate that this active mount, which operates in both the vertical and horizontal directions, effectively mitigates excitation vibrations. Furthermore, a simulation was conducted to mitigate the vibrations caused by complex signals (AM and FM signals) and noise. This was achieved by monitoring the system response using an adaptive filter NLMS algorithm. Adaptive filter simulations demonstrate that the control efficacy degrades in response to complex signals and noise, although the overall relaxation trend remains unchanged.

Analysis and verification of vibration isolation performance of engine mount based on low-frequency approximation method

At present, most of the turbofan engine use the articulated link mount to connect the engine to the wing. The mechanical modeling, analysis and experimental research of articulated link mount are important means in the development of engine mount. In this paper, multibody dynamics method is used to establish the dynamic theory equation for a certain type of turbofan engine mount, and the low-frequency approximation method of the MNF file is proposed, which greatly improves the calculation speed on the basis of ensuring the calculation accuracy. In addition, a full-scale engine mounting system vibration isolation performance test platform was developed, and the vibration isolation efficiency of a certain type of engine mount at the high and low pressure rotor frequency was obtained. The results show that the simulation and test results agree well, the error is within 15% at the low-frequency, and 5% at the high-frequency. This work provides theoretical method and test evaluation means for the design and improvement of large passenger aircraft engine installation devices.

High-power turboprop engine mounting system forward design technology review and a case study

High-power turboprop engine mounting system forward design technology review and a case study

Vibration characteristics of an active mounting system for motion control of a plate-like structure in future mobilities

The vibration and noise caused by electric motors in hybrid and electric vehicles (EVs) generate complex signals with a mid-frequency band, which causes uncomfortable vibration and noise. In order to isolate the vibration and noise, active engine mounting systems based on smart structures have attracted attention. Thus, in this study, the vibration attenuation performance was validated through simulation and feasibility experiments by applying an active mounting system using a piezoelectric stack actuator. A plate structure with three paths, consisting of two passive paths and one active path, was modeled using the lumped parameter method. The source part was excited by a sinusoidal and modulated signal with a mid-frequency band to validate the vibration attenuation performance. Furthermore, (1) mathematical modeling with a source-path-receiver structure was proposed based on lumped parameter modeling, (2) normalized least mean square (NLMS) and multi-NLMS algorithms were applied to implement motion control, and (3) a principal experimental setup was designed to validate the simulation results. Through this process, the vibration attenuation performance of the proposed active mount structure was validated.

Location optimization standard of passive–active vibration isolation element for plate structures in next generation mobilities

The automotive industry has transitioned from internal combustion engine (ICE) vehicles to electric vehicles (EVs) in recent years. Also essential to the development of the next generation are the enhancement of engine performance and production of lightweight vehicle bodies. Through this method, it is possible to increase vehicle output. However, as the vehicle’s excitation strength increases, structural noise and vibrations caused by the engine increase. Intelligent structure-based active mounting systems are widely used in the automotive industry to reduce vibration and noise. It can continuously control the dynamic characteristics of the mount system, enabling real-time control of active mounting systems. When determining the position of the active mounting system, it must be installed in the most efficient position possible. Therefore, the purpose of this study is to determine the optimal placement criteria for an active mounting system consisting of a piezoelectric actuator and a rubber grommet. The lumped parameter model is used to model the plate structure with two hybrid mounting systems based on the source–path–receiver structure. In addition, the forces of two active mounts are calculated using static and dynamic approaches. When the calculated force on the hybrid mount system is relatively low, the location with the greatest vibration reduction can be determined, and this location can be regarded as the optimal location for the active mounting system. In addition, a feasibility test is conducted to validate the proposed criteria and validate the static and dynamic results. The findings indicate that the optimal location for the active engine mounting system can be determined.

Optimal placement criteria of hybrid mounting system for chassis in future mobility based on beam-type continuous smart structures

Recently, research into the development of hybrid and electric vehicles has been vigorously undertaken, indicating a trend toward the replacement of internal combustion engine vehicles. However, while high efficiency and light weight are crucial in the development of vehicles, they increase the excitation force of the engine. In addition, sensor placement in future mobility is very important since it causes malfunctioning of autonomous driving systems when the location and orientation of sensors are changed due to excessive vehicle vibration. To reduce the structure-borne noise and vibration caused by engine excitation, an active engine mounting system must be installed in an optimal location. Thus, in this study, to determine the optimal location for an active engine mounting system applied to a beam structure, a series of simulations with two different methodologies are performed. The overall beam structure with two active mounting systems is modeled based on the lumped parameter model. To determine the optimal position of the active mounting system, it is moved to equal intervals, and the force and phase of the active mounts at each location combination are calculated based on static and dynamic methods. The optimal position is suggested such that the vibration reduction is maximized, while the applied force is minimized. Additionally, a feasibility experiment is conducted to validate the proposed criteria and confirm the simulation results. The results demonstrate that the optimal location of the active engine mounting system with a minimized force requirement and maximized vibration reduction can be identified.

Multi-directional active vibration control of 1D smart structure inspired by automotive engine mounting system

Recently, active mounting system is being gradually applied to automotive engine mounts for mitigating structure-borne vibration effectively throughout the whole vehicle chassis. This paper presents modeling, analysis, and control of a source structure with an active mounting system in multi-directions, considering position and direction of actual automotive engine mounts. The active mount consists of a piezoelectric stack actuator in series with an elastomeric (rubber) mount. When harmonic excitation forces are employed, secondary force required for each active mount is calculated mathematically and the control signal can reduce the vibration through the destructive interference with input signal. In addition, the horizontal vibration can also be mitigated by setting a variable parameter through the dynamic relation of source structure. A series of simulation results demonstrate that the excitation vibration could be reduced along with this multi-directional (vertical and horizontal) active mounts. Based on this result, it can be expected that noise vibration harshness(NVH) performance can be improved by controlling the vibration of the actual automotive engine structure with rubber mount and secondary force of actuators in both vertical and horizontal directions.

Planar Dynamics of a Motorcycle: Parameter Sensitivity of Ride Comfort to Engine Mounting System Nonlinearities

Planar Dynamics of a Motorcycle: Parameter Sensitivity of Ride Comfort to Engine Mounting System Nonlinearities

Principle and Control of Active Engine Mount Based on Magnetostrictive Actuator

Engine mount system affects the automobile NVH performance. Active mounts would achieve excellent vibration isolation and relative displacement control performance in a broad frequency bandwidth by outputting controlled force to the mounting system. The actuator and control method of the active mounts determine the system performance. In this paper, an active mount based on the smart material, i.e., Terfenol-D rod, is proposed, which mainly includes three parts: rubber spring, magnetostrictive actuator (MA), and hydraulic amplification mechanism (HAM). Dynamic model of the active mount is correspondingly established. A state feedback control method based on x-LMS (Least-Mean-Square) algorithm is proposed as well. Specifically, with the consideration of the unmeasurable state parameters in the active mounting system, an x-LMS state feedback controller with the system state as the reference signal is constructed by employing Sage-Husa Kalman filter to realize the state estimation of the active mounting system. Then a detailed analysis of the proposed control method is conducted, with deriving iterative formula of tap-weight vector. Sequentially, the problem of the dependence on the excitation signal in the x-LMS algorithm is addressed. The feasibility and capability of the proposed control method are verified and evaluated by simulation of a two-degree-of-freedom active mounting system.

Optimization of engine and transmission mounting system for a V6 front wheel drive vehicle

Engine mounts helps to attach power train with the frame of the vehicle. The engine mounts help to keep the power- train in its position with the SUV chassis as vehicle experiences several torque loads and inertial loads. The mounting system helps in controlling the motion of the engine and transmission unit, preventing it from physical contact with other components of the vehicle system from sudden impact due to vibrations. The power train Mounting system helps in several ways to keep the engine and transmission unit firmly in its position during vehicle motion and helps in better drivability. Engine along with transmission unit con– tributes 25% of total weight of vehicle, it is important to isolate noise and vibration generated in the engine entering into the vehicle cabin, as power train is the source of vibration in the vehicle. So, it is important to study and investigate rigid body mode shapes for the engine and transmission unit for particular position of mounting unit and spring stiffness. This paper investigates the engine mounting system location and spring stiffness for a vertically mounted v8 engine. The engine and transmission unit mounted on vehicle chassis by elastomeric bushings. The bushing acts as spring mass damper system, helping in isolation of vibration and noise entering into cabin also prevents physical contact of engine with other critical vehicle components. Design of experiments approach is used to study effects of design variables. By varying mount location and stiffness rates the effects of these variable on the power train mounting system is studied and appropriate mounting location and stiffness rates is suggested to improve overall NVH performance of the power train.

Topology Optimization of an Engine Mounting Bracket

Engine mounting system is an essential component to a vehicle in providing the isolation of vibration and noise which are generated by the engine. While various system designs have been studied for improvements, less attention were given to study the effects of vibrational load to subcomponents of the mounting system – for example: the engine bracket. At high frequency working condition, the engine bracket may experience fatigue failure due to cumulative vibrational loading. Henceforth, any efforts to further reduce the structural weight of the said brackets may degrade its strength and this may lead to catastrophic result. This study aimed to enhance the mechanical property of an engine-mounting bracket with respect to cyclic load by means of weight-reduction topology optimization. An actual enginemounting bracket under vibrational load transmitted was modeled and analyzed using two different computer aided design software. An improved design of engine mounting bracket was modeled by reducing its total weight via the use of HyperWorks. In conclusion, this study has discovered an incremental of stress concentration area across the bracket when predetermined load is applied to the weight-reduced engine bracket.

Design optimization of engine mounting system for a modular electric vehicle platform with different powertrain characteristics

In recent days, there is much focus on the modularity of the platform to reduce the cost and improve the system-level design efficiency. In this paper, a study has been done for various non-linear input torque (different powertrain) and optimization with a modular powertrain mounting system where only stiffness is varied to achieve the optimization goal. Here, the optimization goals are maximization of kinetic energy distribution to improve the decoupling rate and minimization of powertrain CoG movement under torque. HEEDS and MATLAB optimization tools are used for analysis. First, three different powertrains are considered individually for optimization. Then, all three powertrains for a particular location on the modular platform are optimized with different mount stiffness. Different mount stiffnesses are chosen in such a way that the stiffness can be achieved only by hardness adjustment or minimum design modification without any change in complete mount design. Proposed results show that a properly chosen mounting system can address the platform modularity quite quickly.

FRF 기반 부분구조합성법을 이용한 차량 진동성능 강건설계

In this study, a robust design procedure using the FRF-based substructuring (FBS) method was proposed for vehicle vibration performance. In the robust design procedure, global sensitivity analysis was used to obtain the design information of elastomers in structural systems considering uncertainties. The global sensitivity method combines the random balance design method for variance-based sensitivity information and the FRF-based substructuring (FBS) method for the calculation of vibrational responses, which establishes an efficient tool even in complex real structures. Moreover, a multi-objective optimization formulation was applied to obtain the optimal design of elastomers that give robust vibration responses. The objective functions were set to the mean and variance of the vibration responses. The Pareto optimal front was calculated using the non-dominated sorting genetic algorithm-II (NSGA-II). The genetic algorithm design variables were screened using the global sensitivity analysis results for the elastomers. These formulations were applied to a passenger car problem to obtain the optimal design of the engine mount systems. The numerical results showed that the newly introduced feature enhanced the calculation performance and the proposed procedure can be applied successfully in real complex structural problems.

Study on the influence of sudden load at idle condition on vibration and vibration isolation performance of the engine mount system

Engine vibration is one of the main excitation sources of vehicle vibration. In order to study the problem of excessive vibration in the cabin of a light vehicle when the air conditioning is turned on at the idle speed, this study is conducted from the point of view of in-cylinder combustion caused by sudden load. The vibrations of the engine with the air conditioning on and off at the idle condition were studied experimentally. The results show that when the air conditioning is turned on at low idle speed, the cylinder pressure rise rate increases with the increase of fuel injection. In addition, the combustion pressure in the cylinder also increases, which leads to the increase of engine vibration. At the same time, a spectrum analysis is carried out in terms of the vibration signal in the maximum direction of the vibration intensity of the suspension system, and the vibration isolation rate is calculated. The results show that the vibration intensity at the second order is the largest, and the vibration isolation effect of the rear suspension is poor.

Study on the dynamic mechanical properties of magnetorheological elastomer (MRE) with Fe@C

Magnetorheological elastomer (MRE) is a promising type of smart material, suitable for shock absorbers in tank engine mount systems. In order to improve the performance of the shock absorber, we improve the magnetorheological (MR) effect of the MREs and reduce its loss factor by enhancing the interaction force between the particles and the substrate. In this work, a novel carbon-coated iron material was prepared by heat treatment, and then carbon-coated iron (Fe@C) of different proportions was added to natural rubber to prepare MRE samples. The tensile strength and elongation at break of the MRE samples were tested by a universal electronic tension machine. The results indicated that better bonding strength between the particles and the matrix increased in tensile strength. The MR effect and the loss factor of the MRE samples were tested by a rheometer. The results demonstrated that the MR effect of MREs modified with Fe@C was significantly improved, and the loss factor of this kind of MRE decreased markedly.

Study on Test and Evaluation of Engine Mounting System Based on Transmission Force

The vibration isolation performance of the engine mounting system can be evaluated by the transmission force. The transmission force characteristics of engine mounting system are analyzed by simulation and test. The 6-DOF model of engine mounting system is established by ADAMS software. The results of modal parameters and transmission force of engine mounting system are obtained by simulation. The force sensor is made with resistance strain gauge. The sensor is calibrated by chassis dynamometer method. The transmission force of the engine mounting system is tested under the complete vehicle condition. The test results of transmission force and acceleration transmissibility are compared. It is proved that the transmission force is more suitable to evaluate the vibration isolation performance of the mounting system when the vehicle is running at medium and high speed.

Research on Test Method and Sensor of Engine Mount Transmission Force

The engine mount transmission force can be used as an important basis to evaluate the vibration isolation performance of the engine mounting system. However, there is a lack of testing equipment and methods for the transmission force. The force sensor and the test method of the transmission force is studied. The finite element model of the mounting element is established to analyze the arrangement position of the sensor. The force sensor is developed based on the resistance strain gauge. The sensor is arranged in the middle of the intermediate bolt. The test system of mount transmission force is established at the same time. The driving force of driving wheel is obtained through the chassis dynamometer test. The force sensor is calibrated base on the test data. The results of mounting transmission force are obtained through the vehicle road test.

Idle shake vibration optimization of an engine mounting system through the practical application of transfer path analysis

This article presents a practical application of experimental transfer path analysis (TPA) for optimizing idle shake vibrations of a front-wheel-drive car with a transversely mounted four-cylinder diesel engine. Performance control of the vehicle engine mounting system must take into account the multiple dynamic interactions between the engine mounting system, subframe modes and the vehicle suspension. Experimental methods can be used in conjunction with simulations to design and optimize the engine mounting system. TPA is a powerful tool for the diagnosis of vibration and noise transmission via multiple solid paths. TPA allows a quick diagnosis of the engine mounting system performances on vehicle comfort. A strong synergy between numerical model and experimental data finally makes it possible to find better design alternatives, not necessarily obvious to the designer. This study is the guideline for an optimization of the engine mount noise vibration and harshness (NVH) performances by using a hybrid approach, combining an analytical approach and measurement data. First, a diagnosis of the transmission of structure-borne vibrations via the engine mounting system to the seat floor is done at constant idle speed. This method is used to rank individual engine mount contributions in the low-frequency vibration level inside the vehicle. Then, an original approach allows the optimization of the vibration level at idle speed by offsetting contributions of the engine mount paths by adding damping in the right engine mount. This approach has led to the design and validation of an original double inertia-track hydroelastic mount prototype which allows a 5-dB reduction on the seat floor vibration level. The future development of a new version is planned to confirm and optimized the obtained results. The length of the second inertia track will be increased to reach the targeted characteristics, and the adjustment system will be removed to respect the overall dimension constraints of the mount.

Parameter Identification in Nonlinear Mechanical Systems with Noisy Partial State Measurement Using PID-Controller Penalty Functions

Dynamic models of physical systems often contain parameters that must be estimated from experimental data. In this work, we consider the identification of parameters in nonlinear mechanical systems given noisy measurements of only some states. The resulting nonlinear optimization problem can be solved efficiently with a gradient-based optimizer, but convergence to a local optimum rather than the global optimum is common. We augment the dynamic equations with a morphing parameter and a proportional–integral–derivative (PID) controller to transform the objective function into a convex function; the global optimum can then be found using a gradient-based optimizer. The morphing parameter is used to gradually remove the PID controller in a sequence of steps, ultimately returning the model to its original form. An optimization problem is solved at each step, using the solution from the previous step as the initial guess. This strategy enables use of a gradient-based optimizer while avoiding convergence to a local optimum. The efficacy of the proposed approach is demonstrated by identifying parameters in the van der Pol–Duffing oscillator, a hydraulic engine mount system, and a magnetorheological damper system. Our method outperforms genetic algorithm and particle swarm optimization strategies, and demonstrates robustness to measurement noise.