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2015-04-14
Technical Paper
2015-01-0661
Jianwang Shao, Xian Wu, Na Wei, Ding Wang, Guoming Deng, Ming Xu
An increasing demand for vehicle noise control has been proposed and at the same time, vehicle weight and fuel economy have become critical for the automotive industry. The methodology of statistical energy analysis (SEA) is used to balance both light weight and high noise insulation performance. In this paper, the vehicle dash and floor sound package systems, which are two of the major paths for vehicle interior noise, are studied and optimized by CAE and testing technology. Two types of sound package which are the conventional insulation system and the lightweight one are chosen for the vehicle dash and floor system. The vehicle dash and floor systems are modeled by SEA and the transmission loss (TL) of the dash and floor system is analyzed, respectively. Several influence factors of the TL are also analyzed, such as sound package coverage, the leaks, etc.
2015-04-14
Technical Paper
2015-01-0216
Ping-Min Hsu, Ming Hung Li, Kuo-Ching Chang
This paper studies noise filtering in an autonomous emergency braking (AEB) system with a sensor fusion between a millimeter wave (MMW) radar and a camera. The AEB system may automatically brake cars by mistake due to the sudden appearance of noise signal if it does not involve any noise filtering mechanism for the object sensor. This may cause some accidents. To avoid such accidents, we propose the filters for three kinds of noise—named as twice harmonic noise, ground noise, and specular refection noise—which are commonly suffered while applying MMW radars. The former is caused by the reflection of a radar wave between a target object and the MMW radar. Based on the concern that the MMW radar evaluates the sensing distance based on the time interval between the transmitting and receiving of the radar wave, one of the sensing distances would be twice as longer as one of others due to the wave reflection. The object featuring this characteristic is further filtered.
2015-04-14
Technical Paper
2015-01-1123
Jiangwu Zhang, Donghao Liu, Haisheng Yu
Torsional vibrations of the full hybrid electric vehicle driveline with a novel single-mode power-split transmission are investigated, in which three power sources, internal combustion engine (ICE), motor/generator 1 (MG1) and motor/generator 2 (MG2) are equipped. The compound planetary gear unit inside the transmission provides the driveline output with continuously variable gear ratios and serves as a power splitting device. Though very similar in configuration, the compound planetary gear used herein is a novel variation of Ravigneaux planetary gear set. MG1, MG2 and ICE are connected to the small sun gear (S1), the large sun gear (S2), the planetary carrier (C), respectively. The ring gear (R) is connected to the final reduction gear (FR), outputting tractions by the conventional differential (DF) to the right and left half shafts for the front wheels.
2015-04-14
Technical Paper
2015-01-1122
Kengo Yabe, Toru Inagaki, Takashi Kondo
Seat vibration when the vehicle is idling and when it is in motion has been reduced by using a floating seat that controls the resonance frequencies. The resonance frequency is controlled by replacing the structures of the seat-mounting unit with floating structures using rubber bushings. Partly replacing the mounting unit with floating structures makes it possible to control the resonance frequencies of the entire seat. The issue of balancing vibration reduction with strength and durability and crash safety performance due to fitting rubber bushings to the seat-mounting unit was addressed using stopper structures optimized for each type of input. To adopt a floating seat into an actual vehicle, the floating structure and conventional foot bracket are combined. This combined foot bracket not only makes it easy to assemble floating structure into the seat, but also makes it possible to keep the seat weight almost the same as a conventional seat.
2015-04-14
Technical Paper
2015-01-0430
Frédéric Kihm, Andrew Halfpenny, Benoît Beaum
Rotating machinery are found in every industry. While some machines are designed for constant-speed operation, others, such as the engines and transmission systems used in ground vehicles, are designed for varying speeds. The vibration environment of a varying speed engine or transmission system is best represented using a ‘Swept-Sine-On-Random’ vibration profile. The vibration profile comprises a mixture of deterministic signals, due to the engine rotation orders, superimposed on a background of Gaussian stochastic noise. Components mounted on these rotating machines are designed to survive these vibration levels over their entire service life. In the past many vibration test specifications were based on either a Power Spectral Density (PSD) function of random noise or as a series of discrete sine sweeps. The advantage of a Swept-Sine-On-Random profile is it is more characteristic of the real vibration environment.
2015-04-14
Technical Paper
2015-01-0235
Shiv Shankar Prasad, Jahangir Mansoori, Jin Seo Park
A vehicle horn is a sound-making device used to warn others of the approach of the vehicle or of its presence. Some countries require horns by law. Conventional Horns are electromechanical with steel diaphragm and electromagnet acting upon it. Switching of horn is performed by mechanical contact breaker assembly that repeatedly interrupts the current to the electromagnetic. Up-Down Movement of diaphragm with response to the current creates a sound wave across the horn. Conventional Horn faces the problem of wear and tear of mechanical contact and internal parts. Switching of contacts results in Arcing .There is no current and surge voltage protection for the coil of conventional horn. These problems of conventional system might be OK in the general markets. But in specific markets which are using horn frequently, these have to be considered as serious issues. Especially, horns are one of the most abusing parts of vehicle in India.
2015-04-14
Technical Paper
2015-01-0663
Ling Zheng, Zhanpeng Fang, Zhongcai Tang, Zhenfei Zhan, Jiang-hua Fu
The design optimization of vehicle body structure is addressed to reduce interior noise and improve customer satisfaction in this paper. The structural-acoustic model is established and the response of sound pressure in frequency domain is obtained by using finite element method. The minimization of sound pressure near the driver’s right ear depends on the geometry of vehicle body structure and the layout of damping treatments. The panel participation analysis is performed to find out the key panels as design variables and improve the efficiency of optimization computation. Response Surface Method (RSM) is utilized to optimize the vibro-acoustic properties of vehicle body structure instead of complex structural-acoustic coupling finite element model. Structural-acoustic problem is approximated by a series of quadratic polynomial using RSM. Geometric optimization problem of panels is described and solved to minimize the interior noise in vehicle.
2015-04-14
Technical Paper
2015-01-0831
Wonah Park, Youngchul Ra, Eric Kurtz, Werner Willems, Rolf D. Reitz
The low temperature combustion concept is very attractive for reducing NOx and soot emissions in diesel engines. However, it has potential limitations due to higher combustion noise and CO and HC emissions. A multiple injection strategy is an effective way to reduce unburned emissions and noise in LTC. In this paper, the effect of multiple injection strategies was investigated to reduce combustion noise and unburned emissions in LTC conditions. A hybrid surrogate fuel model was developed and validated, and was used to improve LTC predictions. Triple injection strategies were considered to find the role of each pulse and then optimized. The split ratio of the 1st and 2nd pulses fuel was found to determine the ignition delay. Increasing mass of the 1st pulse reduced unburned emissions and an increase of the 3rd pulse fuel amount reduced noise. It is concluded that the pulse split ratio can be used as a control factor for emissions and noise.
2015-04-14
Technical Paper
2015-01-0666
Chenguang Li, Fue-Sang Lien, Eugene Yee, Mike Dong
A deeper understanding of the complex phenomenology associated with the flow induced noise and vibration in a dynamic valve is of critical importance to the automotive industry. To this purpose, a two-dimensional axisymmetric numerical model has been developed to simulate the complex processes that are responsible for the noise and vibration in a poppet valve (or poppet). More specifically, an Eulerian multiphase flow model, a dynamic mesh and a user-defined function are utilized within the ANSYS-FLUENT software system in order to facilitate the modeling of the complicated two-phase fluid-structure interaction problem associated with the generation of noise and vibration in a poppet valve. In this strongly coupled simulation framework, the poppet valve which is driven by spring and various dynamical fluid forces (e.g., viscous and pressure forces), is modeled as an under-damped vibration system.
2015-04-14
Journal Article
2015-01-1088
Tomohiko Usui, Tomoya Okaji, Tatsuya Muramatsu, Yoshiyuki Yamashita
A low-cost lock-up damper displaying a high level of damping performance has been developed for use in torque converters in automatic transmissions. The new damper was actualized by sharing parts (the turbine and damper components) and optimizing parameters for damping characteristics. The new torque converter displays equivalent conversion performance to a conventional model while reducing the width of the torus by approximately 30%. The combination of the lock-up damper and the small torus has made it possible to reduce torque fluctuation transmitted to the transmission to less than 50% with no increase in the overall width of the torque converter against a conventional model. This has reduced engine speed when the vehicle is cruising by 400rpm, resulting in an increase in fuel efficiency of approximately 2%.
2015-04-14
Technical Paper
2015-01-1124
Gerrit Knabe, Markus Zahlten, Ferit Kücükay
In order to improve the acoustic comfort inside passenger cars in terms of transmission noise, a special method has been developed. For a structured and comprehensive analysis of the transmission noise, the generation and transfer mechanisms are divided into four separate but nevertheless connected parts. Although simulation and components tests are used to analyze vibration excitation which may cause rattle and the mechanisms causing rattle in detail, they are not the main part of the analysis. The focus of this study is on the transfer of automotive transmission rattle and the passengers’ perception. The noise characteristics, which can be specified using conventional analysis methods as well as assessments by test persons, are important for the transfer path of the disturbing noise. By combining different methods of transfer path analysis (TPA), direct airborne-sound transmission is identified as a significant transfer path of the rattling noise.
2015-04-14
Technical Paper
2015-01-1195
Kiyotaka Maeda, Masashi Takahashi
To verify the appropriateness of the vibration test conditions of ISO 12405, we derived power spectrum densities and test durations as vibration test conditions by tailoring. Vehicles used for tailoring included two electric vehicles and one plug-in hybrid electric vehicle. Those vehicles were equipped with accelerometers and run on seven different types of road at different speeds, and the acceleration data that the battery packs received were recorded. The power spectrum densities for three axes that were derived from the obtained acceleration data were similar in form to the power spectrum densities of ISO 12405, and almost the same root mean square value of acceleration were obtained, confirming that they are appropriate. However, it has been suggested both experimentally and theoretically that the test duration for the Z-axis exceeds those of the X and Y axes.
2015-04-14
Journal Article
2015-01-1206
Manabu Yazaki
In recent years, the application of hybrid electric vehicle (HEV) technologies to a wide range of vehicles, from small to large vehicles and sedans to SUVs, has been expanding rapidly. Market demand for quiet drive is strong, and HEV systems are able to operate using motor drive alone, eliminating engine vibration and noise. To reduce torque fluctuation in order to reduce vibration and noise, distributed winding is used in the stators of the drive motors employed in many existing electric vehicles (EV) including HEV. However, because the coil ends of distributed windings are large, space for fitting is restricted. Concentrated winding is one method of reducing the size of the motor, because the coil ends can be made smaller. As winding resistance is lower in concentrated winding than in distributed winding copper loss is reduced, and the coils are effective under high-torque conditions.
2015-04-14
Journal Article
2015-01-0610
Guangqiang Wu, Wenbo Luan
During the launch of a car, severe torsional vibration sometimes may occur in its driveline due to somewhat the slipping of the clutch, its intuitive sense for an occupant is the longitudinal vibration of the vehicle, referred to as the launch shudder, whose characteristic frequency is from 5 to 25 Hz generally. As the main vibratory sources of the driveline and its crucial nonlinear components, variable stiffness and backlash of the gear meshing are considered, their impacts on launch shudder are analyzed in this paper. Conformal mapping, finite element method and regression method etc. are the main approaches to calculate the variable meshing stiffness of a gear pair. If this stiffness is get, it can usually be substituted for its approximate analytical expression, or just with finite harmonic terms, in Fourier series form into Ordinary Differential Equations(ODEs) to calculate the vehicle responses considering its nonlinearity.
2015-04-14
Technical Paper
2015-01-0615
Li Jie, Wang Wenzhu, Gao Xiong
In order to study the problem of vehicle ride, a vibration model of 6 DOF half vehicle based on the synthesis between rigid body and flexibility is established using elastic beam theory of equal section with both ends free. According to pseudo-excitation method, the pseudo road excitations in vehicle front wheel and rear wheel are constructed. The frequency response characteristic of a vehicle system is deduced based on front wheel and a formula for calculating vehicle vibration responses and their power spectrum density is presented with pseudo-excitation method. The power spectral density and the root mean square value of body acceleration act as evaluation index. By comparing the simulation results of rigid model, it shows that body flexibility has a great impact on vehicle ride and it cannot be ignored. The study also shows that pseudo-excitation method is more simple than Fourier method.
2015-04-14
Technical Paper
2015-01-0625
Manfred Baecker, Axel Gallrein, Michael Roller
The tire plays a fundamental role in the generation of acoustically perceptible driving noise and also in the generation of vibrations inside the vehicle. Drivers and passengers will perceive vibrations inside the vehicle as interference of their physical comfort. An essential part of these vibrations will be induced by the road excitation and be transferred via the tire into the vehicle. There are 2 basic ways to study the NVH behavior of a tire or a full vehicle including a tire: • Transient simulation scenario • Frequency based or modal simulation scenario In the first case the tire or full vehicle will be simulated using a transient dynamic simulation method. The vehicle or tire is driving over an arbitrary digitized road profile. There is no need for a stationary driving state or for the necessity of a constant driving velocity.
2015-04-14
Journal Article
2015-01-0622
H. Metered, A. Elsawaf, T. Vampola, Z. Sika
Proportional integral derivative (PID) control technique is the most common control algorithm applied in various engineering applications. Also, particle swarm optimization (PSO) is extensively applied in various optimization problems. This paper introduces an investigation into the use of a PSO algorithm to tune the PID controller for a semi-active vehicle suspension system incorporating magnetorheological (MR) damper to improve the ride comfort and vehicle stability. The proposed suspension system consists of a system controller that determine the desired damping force using a PID controller tuned using PSO, and a continuous state damper controller that estimate the command voltage that is required to track the desired damping force. The PSO technique is applied to solve the nonlinear optimization problem to find the PID controller gains by identifying the optimal problem solution through cooperation and competition among the individuals of a swarm.
2015-04-14
Technical Paper
2015-01-1326
Sivanandi Rajadurai, Guru Prasad Mani, Kavin Raja, Sundaravadivelu Mohan
Generation of discretization with prescribed element sizes are adapted to the geometry. From Rules of thumb, for a complicated geometry it is important to select the reasonable element order, shapes and size for accurate results. In order to that, this paper describes the influence of elemental algorithm of the catalytic converter mounting brackets. Brackets are main source of mounting of various systems mainly intake and exhaust in the engine .In exhaust hot end system, bracket designs play a vital role because it has to withstand heavy structural vibrations without isolation combined with thermal loads. Bracket design and stiffness determines the whole Catalytic converter system's rigidity. So, here discretization of converter brackets by linear and parabolic elements is studied with different elements types and compared.
2015-04-14
Technical Paper
2015-01-0212
Mohamed El Morsy, Gabriela Achtenova
Condition monitoring is used to increase machinery availability and machinery performance, whilst reducing consequential damage, increasing machine life, reducing spare parts inventories, and reducing breakdown maintenance. An efficient condition monitoring system provides early warning of faults by predicting them at an early stage. When a localized fault occurs in gears, the vibration signals always exhibit non-stationary behavior. The periodic impulsive feature of the vibration signal appears in the time domain and the corresponding gear mesh frequency (GMF) emerges in the frequency domain. However, one limitation of frequency-domain analysis is its inability to handle non-stationary waveform signals, which are very common when machinery faults occur. Particularly at the early stage of gear failure, the GMF contains very little energy and is often overwhelmed by noise and higher-level macro-structural vibrations.
2015-04-14
Technical Paper
2015-01-1555
Charalampos Kounenis, David Sims-Williams, Robert Dominy, Arganthaël Berson, Nicholas Oettle, Claire Freeman
A road vehicle encounters unsteady flow conditions as it traverses through the stationary wakes of road side obstacles, but also as a result of turbulence in the natural wind and the unsteady wakes from other on-road vehicles. This work investigates aeroacoustic impacts of steady state and dynamic yaw. The later was simulated using the Pininfarina active Turbulence Generation System (TGS), a system designed to capture some of the effect of time-varying on-road conditions. The results presented are for a production vehicle. This work focusses in particular on investigating changes in noise sources, including through the use of beamforming techniques. Both interior beamforming (noise vision) and exterior beamforming were deployed. In the latter, the beamforming calculations were based on vehicle surface CAD data in order to obtain an enhanced result, in particular when the vehicle is physically yawed relative to the microphone array.
2015-04-14
Technical Paper
2015-01-1558
Amir Kharazi, Edward Duell, Austin Kimbrell, Ann Boh
Unsteady flow over automotive side-view mirrors may cause flow-induced vibrations of the mirror assembly which can result in blurred rear-view images, adversely affecting marketability and driver safety, as well as customer comfort and quality perception. Prior research has identified two mechanisms by which aerodynamically induced vibrations are introduced in the mirror. The first mechanism is unsteady aero pressure loading on the mirror face due to the unsteady wake, causing direct vibration of the mirror glass. The second mechanism, and the focus of this study, is a fluctuating loading on the mirror housing caused by an unsteady separation zone on the outer portion of the housing. A time-dependent Computational Fluid Dynamics (CFD) methodology to correctly model mirror wake behavior, and thereby predict flow-induced mirror vibration to improve performance estimations, was developed.
2015-04-14
Technical Paper
2015-01-1644
Huan Li, Ying Huang, Gang Li, Yongguang Yang
Key Words Diesel engine; Cylinder-by-cylinder variations; Cylinder-by-cylinder control; Torsional vibration Research Objective During the engine working process, the differences of each cylinder’s fuel injection quantity and the manufacturing deviations of mechanical parts will lead to cylinder-by-cylinder variations. It will bring about a large torsional vibration angular displacement of low-frequency and large fluctuation of the engine speed, especially in the idle condition. As a result, it brings down the engine performance and shortens the lifetime of the engine. In order to reduce the bad influences coming with the cylinder-by-cylinder variations, a detection method and an control algorithm of the variations need to be proposed. Methodology The traditional detection methods and control algorithms of cylinder-by-cylinder variations have been researched through literature survey.
2015-04-14
Journal Article
2015-01-1597
Kazuto Yokoyama, Masahiro Iezawa, Hideyuki Tanaka, Keiichi Enoki
Mitsubishi Electric has developed a concept car “EMIRAI 2 xEV” that features an electric vehicle (EV) powertrain for safe, comfortable, and eco-friendly driving experiences in the future. The body of vehicle was exhibited during Tokyo Motor Show 2013 for the first time. xEV is a four-wheel-drive EV that has three motors: a water-cooled front motor and two air-cooled rear motors with integrated inverters. Rear wheels can be driven independently. The degrees of freedom of the actuation can realize improved maneuverability and safety. The vehicle is also equipped with an onboard charger with built-in step down DC/DC converter, an EV control unit, a battery management unit, and an electric power steering. All of the instruments are developed in Mitsubishi Electric Corporation. Motion control systems for xEV have been developed on the basis of our proprietary original motor control technology.
2015-04-14
Journal Article
2015-01-1579
Jun Nakahara, Koji Yamazaki, Yusuke Otaki
There exist some cars which ride performance become less comfortable on smooth road. If vibration transmissibility of suspension system on such a vehicle is evaluated by means of equivalent dynamic stiffness, it is found that the increase of storage stiffness deteriorates the vibration transmissibility of suspension due to the steep rising of hysteresis on wheel-stroke to wheel-load curve when excitation amplitude become small. To improve the ride-comfort performance on smooth road, therefore, the rising shape of wheel stroke curve due to hysteresis components, such as shock-absorber, ball-joints and rubber bushes, should be adjusted to prevent the increase of storage stiffness at small amplitude of suspension stroke. For investigating the hysteresis characteristics of these components, appropriate simulation models, which can reproduce their characteristics accurately, must be installed in the vehicle model and their parameters have to be determined with sufficient accuracy.
2015-04-14
Technical Paper
2015-01-1504
WeiNing Bao
A ball screw regenerative shock absorber was designed for the relief of the vehicle vibration and the energy recovery of the vehicle vibration. The effect of its main parameters on the suspension system was numerically analyzed. According to the principle of the ball screw regenerative suspension system, a mathematical model of the ball screw regenerative shock absorber was established regarding the ball screw rotational inertia, the motor rotational inertia, the screw lead and the radius of the screw nut. A suspension dynamic model based on the ball screw regenerative shock absorber was developed combining the road model and the two-degrees-of-freedom suspension dynamic model.
2015-04-14
Technical Paper
2015-01-0613
Donghong Ning, James Coyte, Hai Huang, Haiping Du, Weihua Li
Heavy duty vehicles suffer from detrimental vibrations which have significant influence to the operator’s comfort, health and safety. Especially, long term exposures to vibration with a frequency range between 0.5 and 10Hz will severely damage the driver’s backbone. Tires, chassis suspension and seat suspension are three traditional methods to isolate vehicles vibration, but it is generally difficult to modify the parameters of tires and chassis suspension, even many approaches are proposed for the performance of chassis suspension. On the other hand, the seat suspension system is easy to modify and optimize. Therefore, seat suspension has been employed as a simple and effective method to isolate vehicle vibration transmitted to the driver’s body. Studying the vibration characteristics of seat suspension is one important step for seat suspension design.
2015-04-14
Technical Paper
2015-01-0618
Zhihong Dong, Ying Sun, Guitao Zhu, Shihu Wang, Jian Zeng, Yuliang Yang
Based on the modal frequency response theory and experiment ,the installation layout evaluation and structural optimization method for SIS(side impact sensors) installation position is studied. Establish the finite element model including B-pillar, roof and floor with local constraint .Than study the key parameter's influence on the frequency response analysis results ,and the simulation results are correlated by experiment. In view of the installation layout requirements of side impact sensors ,the structure optimization method for installation position of side impact sensor is put forward . The optimal scheme is confirmed by the finite element analysis, and a final experimental verification was implemented by a real vehicle test.
2015-04-14
Technical Paper
2015-01-1087
Juergen Greiner, Martin Grumbach, Albert Dick, Christoph Sasse
This is a preliminary version of the abstract to save the date, it will be replaced after discussion with the main author Dr. Jürgen Greiner ZF in short time. The discussion was not possible earlier, due to vacation of the authors and other stakeholders. Marketresearch shows the ongoing worldwide increasing acceptance and success of modern automatic transmissions in passenger cars. This success is based on the further developed of the driving comfort, shifting dynamic and - most important - fuel consumption reduction modern transmission systems show.
2015-04-14
Technical Paper
2015-01-1285
Dingfeng Deng, Fanghui Shi, Louis Begin, Isaac Du
Several instances have occurred where the outer surface of turbocharger fully floating journal bearing bushings have exhibited damage from oil debris resulting in loud constant tone noises and subsequent warranty claims. This paper studies the effect of oil debris in Turbocharger journal bearings on Subsynchronous NVH. A CFD model is built to study the behavior of oil debris particles with different sizes. The oil debris particles tend to navigate to the inner film or outer film of bearing bushing depending on the drag and centrifugal forces. It is found that the dominant centrifugal forces prevent larger particles from reaching the inner film while smaller particles travel more easily to the inner film. It is also found that the turbine side is more likely to become damaged from debris than the compressor side bearing due to higher temperatures. A tribology analysis is executed to determine the effect of oil debris particles on the speed ratio of the bearing bushing to the shaft.
2015-04-14
Technical Paper
2015-01-1671
Mohamed El Morsy, Gabriela Achtenova
In this paper, a fault in rolling bearing is diagnosed using time waveform analysis. In order to verify the ability of time waveform analysis in fault diagnosis of rolling bearing, an artificial fault is introduced in vehicle gearbox bearing: an orthogonal placed groove on the inner race with the initial width of 0.65 mm approximately. The faulted bearing is a roller bearing located on the gearbox input shaft – on the clutch side. An optimal Morlet Wavelet Filter and autocorrelation enhancement are applied in this paper. First, to eliminate the frequency associated with interferential vibrations, the vibration signal is filtered with a band-pass filter determined by a Morlet wavelet whose parameters are optimized based on maximum Kurtosis. Then, to further reduce the residual in-band noise and highlight the periodic impulsive feature, autocorrelation enhancement is applied to the filtered signal.
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