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Viewing 181 to 210 of 8994
2015-04-14
Technical Paper
2015-01-1671
Mohamed El Morsy, Gabriela Achtenova
Abstract 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 0.6 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.
2015-04-14
Technical Paper
2015-01-1675
Yongfu Chen, Zhengfei Tang, Peijun Xu, Yunqing Zhang
Abstract In order to reasonably match the variable stiffness and location of the Powertrain Mounting System (PMS) and optimize the ride comfort of commercial vehicle, a thirteen degrees of freedom (DOF) model of a commercial vehicle was established in Adams/view. Specially, the support rod installed on the upside of the transmission case was modeled as a flexible body. The vibration isolation provided by the PMS was evaluated in three aspects: the energy decoupling of the powertrain, the response force of the mount and the displacement of the powertrain. The energy decoupling ratio, the force RMS of the mount when force excitation was applied on the powertrain and the displacement of the powertrain Center of Gravity (C.G) when displacement excitation was applied on the vehicle chassis were selected as the optimal target. Adams and MATLAB were integrated into the optimization software iSIGHT to optimize the PMS. NSGA-II is used to obtain some Pareto-optimal solutions of PMS.
2015-04-14
Technical Paper
2015-01-1644
Huan Li, Ying Huang, Gang Li, Yongguang Yang
Abstract The cylinder-by-cylinder variations have many bad impacts on the engine performance, such as increasing the engine speed fluctuation, enlarging the torsional vibration and noise. To deal with this problem, the impact mechanism of cylinder-by-cylinder variations on low order torsional vibration has been studied in this paper, and subsequently a new individual cylinder control strategy was designed by processing the instantaneous crankshaft rotation speed signal, detecting the cylinder-by-cylinder variation and using feed-back control. The acceleration characteristics of each cylinder in each engine cycle were compared with each other to extract the variation index. The feed-back control algorithm was based on the regulation of the fuel injection according to the detected variation level.
2015-04-14
Technical Paper
2015-01-0831
Wonah Park, Youngchul Ra, Eric Kurtz, Werner Willems, Rolf D. Reitz
Abstract 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, 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 distribution can be used as a control factor for emissions and noise.
2015-04-14
Technical Paper
2015-01-0825
Gen Shibata, Koki Ishi, Hirooki Ushijima, Yushi Shibaike, Hideyuki Ogawa, David E. Foster
Abstract Premixed diesel combustion offers the potential of high thermal efficiency and low emissions, however, because the rapid rate of pressure rise and short combustion durations are often associated with low temperature combustion processes, noise is also an issue. The reduction of combustion noise is a technical matter that needs separate attention. Engine noise research has been conducted experimentally with a premixed diesel engine and techniques for engine noise simulation have been developed. The engine employed in the research here is a supercharged, single cylinder DI diesel research engine with a high pressure common rail fuel injection system. In the experiments, the engine was operated at 1600 rpm and 2000 rpm, the engine noise was sampled by two microphones, and the sampled engine noise was averaged and analyzed by an FFT sound analyzer.
2015-04-14
Technical Paper
2015-01-0212
Mohamed El Morsy, Gabriela Achtenova
Abstract 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. An effective signal processing method would be necessary to remove such corrupting noise and interference. In this paper, a new hybrid method based on optimal Morlet wavelet filter and autocorrelation enhancement is presented.
2015-04-14
Technical Paper
2015-01-0216
Ping-Min Hsu, Ming Hung Li, Kuo-Ching Chang
Abstract This paper discusses noise filtering in an autonomous emergency braking (AEB) system with a sensor fusion between a millimeter wave (MMW) radar and a camera. Three kinds of noise, namely twice harmonic noise, ground noise, and specular reflection noise, are then filtered. The former is caused by the reflection of a radar wave between a target object and the MMW radar; therefore, one of the sensing distances would be twice as longer as one of others. An object featuring this characteristic is treated as the noise and filtered. Next, detecting a ground metal as the target object generates the second noise with a focus of car-like objects. That is, an object-with the sensing distance from the MMW radar being smaller than that from the camera by a threshold value-is taken as the ground metal noise and ignored. Moreover, the third noise happens when there is a radar wave reflection between an object and its surroundings.
2015-04-14
Technical Paper
2015-01-0235
Shiv Shankar Prasad, Jahangir Mansoori, Jin Seo Park
Abstract A vehicle horn is a sound-making device used to warn others of any approaching 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 electromagnetic. Up-Down movement of diaphragm with response to the current creates a sound wave across 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 accepted in the general market, but in specific markets which are using horn frequently; these have to be considered as serious issues. Especially, horns are one of the most abusive parts of vehicle in India.
2015-04-14
Technical Paper
2015-01-0430
Frédéric Kihm, Andrew Halfpenny, Benoît Beaum
Abstract As part of the design and validation of engine-mounted components, it is essential to define the vibratory mechanical environment in which these components will operate. This is required in order to optimize the reliability of such components subjected to loading from both the engine and road profile, while minimizing development costs and time scales. This paper presents a methodology that superimposes a swept sine on a power spectral density of acceleration in order to evaluate the mechanical durability of engine mounted or gear box mounted components. The first step in the process is to obtain the wave form of the dominant engine orders by extracting the deterministic signals from the random process using an order tracking method in the time domain. The second step is to assess the fatigue damage and extreme response spectra of a Swept-Sine-On-Random profile.
2015-04-14
Technical Paper
2015-01-0666
Chenguang Li, Fue-Sang Lien, Eugene Yee, Mike Dong
Abstract A deeper understanding of the complex phenomenology associated with the multiphase 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. More specifically, an Eulerian multiphase flow model, a dynamic mesh and a user-defined function are utilized to facilitate the modeling of this complicated two-phase fluid-structure interaction problem. For a two-phase flow through the valve, our simulations showed that the deformation and breakup of gas bubbles in the gap between the poppet and the valve seat generates a vibration that arises primarily from the force imbalance between the spring and the two-phase fluid flow induced forces on the poppet.
2015-04-14
Technical Paper
2015-01-1504
WeiNing Bao
Abstract 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
2015-01-1668
Chetankumar Patel, Nachiketa Tiwari, Avinash Kumar Agarwal
Abstract High viscosity of vegetable oil causes ignition problems when used in compression ignition engines. There is a need to reduce the viscosity before using it as engine fuel. Preheating and pre-treating of vegetable oils using waste heat of exhaust gases is one of the techniques, which reduces the viscosity and makes it possible to use it as alternate fuel for some niche applications, without requiring major modifications in the engine hardware. Several applications such as decentralized power generation, agricultural engines, and water pumping engines, can use vegetable oils as an alternative fuel. In present investigation, performance, combustion, and emission characteristics of an engine using preheated 20% blend of Jatropha oil with mineral diesel (J20) has been evaluated at a constant speed (1500 rpm) in a single cylinder four stroke direct injection diesel engine.
2015-04-14
Technical Paper
2015-01-1670
Can Tao, Hengjia Zhu, Peijun Xu, Yunqing Zhang
Abstract Hydraulic Engine Mount (HEM) is widely used in vehicle Powertrain Mounting System (PMS) for vibration isolation. The dynamic performances of an HEM are strongly frequency dependent. A Five-Parameters Fractional Derivative model is used to describe the dynamic properties of an HEM. A 1/4 car model is applied to evaluate the effect of frequency-dependent dynamic stiffness which using measured data of a typical hydraulic engine mount. The excitations from engine and road are considered in the simulation. The generalized- α method is presented to solve the vehicle model with five-parameter fractional derivative model.
2015-04-14
Technical Paper
2015-01-1666
Lingzhi Li, Yimin Yang, Fengjun Zhao, Zhi Zhang, Hailong Cheng, Hangsheng Hou
Abstract An issue of engine squealing in low temperature range (around −25°C) right after start-up emerged for a significant number of vehicles in a vehicle program. The earlier effort had focused on typical common culprits such as the pulley-belt systems etc. However, much effort, by subjective listening and guestimating hardware replacement, yielded no fruitful results for more than a year. The application of near-field acoustic holography on top of the engine in a climate chamber quickly identified several noise source locations. Further noise source identification effort on top, front and left side of the engine pinpointed the top three noise source locations: the idler pulley and water pump on front, the air compressor on right side, and the air intake throttle on top. Then a series of experiments were subsequently conducted, leading to a conclusion that the idler pulley was the source of the issue.
2015-04-14
Technical Paper
2015-01-0625
Manfred Baecker, Axel Gallrein, Michael Roller
Abstract The tire plays a fundamental role in the generation of acoustically perceptible driving noise and vibrations inside the vehicle. An essential part of these vibrations is induced by the road excitation and transferred via the tire into the vehicle. There are two basic ways to study NVH behavior: Simulations in time and frequency domains. The system can be simulated using a transient simulation method with the disadvantage of high simulation and process turnaround times. Alternatively, a linearization around a stationary state is performed and solved in frequency domain with fast numerical schemes. Modelling the tire transfer behavior in frequency domain requires special attention to the rotation of the tire. This paper shows the approach taken by the authors to include the transfer behavior in the frequency range up to 250 Hz from geometric road excitations to resulting spindle forces in frequency domain. Special care has been used in the modelling of local road excitations.
2015-04-14
Collection
This technical paper collection sets out to reflect the recent advances on the research, development and practices of Powertrain NVH treatment. The technical papers are of interest to powertrain system designers, testing specialists, NVH experts, and other individuals who evaluate and develop technologies to control powertrain NVH. The coverage includes: engine, engine subsystem and components noise and vibration; powertrain systems noise measurement and instrumentation; powertrain systems noise analysis.
2015-04-14
Technical Paper
2015-01-1087
Juergen Greiner, Martin Grumbach, Albert Dick, Christoph Sasse
Abstract Market trends clearly demonstrate the ongoing worldwide acceptance and success of modern automatic transmission solutions (AT, CVT, DCT) in both passenger cars and light trucks. This success is based on the further development of the driving comfort, shifting dynamics and - most important - the fuel consumption reduction modern automatic transmission systems offer. First, key driveline parameters such as overall spread and number of ratio's are to be discussed. The optimum spread for the fuel efficiency is in the range of about 8 to 9 and can typically be achieved by 8 to 10-speed transmissions. This is because modern gasoline or diesel-engines have a rather flat characteristic fuel map. Therefore the inner efficiency of the future transmissions becomes increasingly important.
2015-04-14
Technical Paper
2015-01-1124
Gerrit Knabe, Markus Zahlten, Ferit Kücükay
Abstract 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 [1, 2], 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
2015-01-1113
Jae Sung Bang, Young-Kwan Ko, Tae-Hee Jung
Abstract In this paper, we consider the driveline oscillations for electric vehicles. The oscillations in the electric vehicle result from the lack of the damping component such as a torque converter. The oscillations should be suppressed for the ride comfort. The new method is suggested using wheel speeds and the newly designed filter. The method guarantees better performance to eliminate the oscillations and better robustness against disturbances such as a brake force, road slope, and so on. The effectiveness of the suggested method is verified by experimental results.
2015-04-14
Technical Paper
2015-01-1396
Xiangjie Meng, Xin Tao, Wenjun Wang, Chaofei Zhang, Bo Cheng, Bo Wang, Chengpeng Zhou, Xiaoping Jin, Chao Zeng, John Cavanaugh, Chaoyang Chen
Abstract Low back pain has a higher prevalence among drivers who have long term history of vehicle operations. Vehicle vibration has been considered to contribute to the onset of low back pain. However, the fundamental mechanism that relates vibration to low back pain is still not clear. Little is known about the relationship between vibration exposure, the biomechanical response, and the physiological responses of the seated human. The aim of this study was to determine the vibration frequency that causes the increase of muscle activity that can lead to muscle fatigue and low back pain. This study investigated the effects of various vibration frequencies on the lumbar and thoracic paraspinal muscle responses among 11 seated volunteers exposed to sinusoidal whole body vibration varying from 4Hz to 30Hz at 0.4 g of acceleration. The accelerations of the seat and the pelvis were recorded during various frequency of vibrations. Muscle activity was measured using electromyography (EMG).
2015-04-14
Technical Paper
2015-01-0631
Cuiping Feng, Zhihong Dong, Yuliang Yang, Chaoxing Xie, Kai Wang
Abstract The vibration theory and dynamic vibration absorber (DVA) theory is presented. Based on the finite element analysis and rigid-flexible coupling analysis, combined with an engineering example, drive shaft analysis model including DVA was established. The effects of DVA's parameters on the dynamic response of the main system, such as frequency ratio, mass ratio, installed position and damping ratio were studied independently as an experimental design. The studied conclusion was used to optimize DVA directionally, and optimization of multiple factors was completed. In this paper, the optimization design of a drive shaft with DVA was completed and a final test evaluation was implemented, that the rigid-flexible coupling analysis method was verified.
2015-04-14
Technical Paper
2015-01-0663
Ling Zheng, Zhanpeng Fang, Zhongcai Tang, Zhenfei Zhan, Jiang-hua Fu
Abstract 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 developed by using finite element method. The frequency response of structural-acoustic system is computed by modal analysis method. The optimization problem is constructed to minimize the sound pressure level in the right ear of the driver. The sensitivity analysis is carried out to find the key panels to be optimized as design variables and improve the efficiency of optimization computation. Response Surface Method (RSM) is utilized to develop the surrogate model and optimize the vehicle Noise Vehicle and Harshness (NVH) behavior. A 9dB reduction of sound pressure level (SPL) in the right era of the driver is obtained through geometric optimization for panels. Furthermore, the topology optimization model is developed to search the optimal layout of constrained layer damping treatments in the front floor.
2015-04-14
Technical Paper
2015-01-0661
Jianwang Shao, Xian Wu, Na Wei, Ding Wang, Guoming Deng, Ming Xu
Abstract 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 packages 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
Journal Article
2015-01-1206
Manabu Yazaki
Abstract A new motor has been developed that combines the goals of greater compactness, increased power and a quiet drive. This motor is an interior permanent magnet synchronous motor (IPM motor) that combines an interior permanent magnet rotor and a stator with concentrated windings. In addition, development of the motor focused on the slot combination, the shape of the magnetic circuits and the control method all designed to reduce motor noise and vibration. An 8-pole rotor, 12-slot stator combination was employed, and a gradually enlarged air gap configuration was used in the magnetic circuits. The gradually enlarged air gap brings the centers of the rotor and the stator out of alignment, changing the curvature, and continually changing the amount of air gap as the rotor rotates. The use of the gradually enlarged air gap brings torque degradation to a minimum, and significantly reduces torque fluctuation and iron loss of rotor and stator.
2015-04-14
Technical Paper
2015-01-1558
Amir Kharazi, Edward Duell, Austin Kimbrell, Ann Boh
Abstract 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 through 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 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 was developed to correctly model mirror wake behavior, and thereby predict flow-induced mirror vibration to improve performance estimations.
2015-04-14
Technical Paper
2015-01-1555
Charalampos Kounenis, David Sims-Williams, Robert Dominy, Arganthaël Berson, Nicholas Oettle, Claire Freeman
Abstract A vehicle driving on the road experiences unsteady flow conditions which are not generally reproduced in the development environment. This paper investigates the potential importance of this difference to aeroacoustics and hence to occupant perception and proposes a methodology to enable better ranking of designs by taking account of wind noise modulation. Two approaches of reproducing the effects of unsteady wind on aeroacoustics were investigated: an active wind tunnel Turbulence Generation System (TGS) and a quasi-steady approach based on measurements at a series of fixed yaw angles. A number of tools were used to investigate the onset flow and its impacts, including roof-mounted probe, acoustic heads and surface microphones. External noise measurements help to reveal the response of separate exterior noise sources to yaw.
2015-04-14
Journal Article
2015-01-0610
Guangqiang Wu, Wenbo Luan
Abstract 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 vibration sources of the driveline and its crucial nonlinear components, the variable stiffness and backlash of the gear meshing are considered, their impacts on the 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, just with finite harmonic terms, in Fourier Series form into Ordinary Differential Equations(ODEs) to calculate the vehicle responses with its nonlinearity considered.
2015-04-14
Journal Article
2015-01-0612
Weiguo Zhang, Zeyu Ma, Ankang Jin, James Yang, Yunqing Zhang
Abstract Nowadays, studying the human body response in a seated position has attracted a lot of attention as environmental vibrations are transferred to the human body through floor and seat. This research has constructed a multi-body biodynamic human model with 17 degrees of freedom (DOF), including the backrest support and the interaction between feet and ground. Three types of human biodynamic models are taken into consideration: the first model doesn't include the interaction between the feet and floor, the second considers the feet and floor interaction by using a high stiffness spring, the third one includes the interaction by using a soft spring. Based on the whole vehicle model, the excitation to human body through feet and back can be obtained by ride simulation. The simulation results indicate that the interaction between feet and ground exerts non-negligible effect upon the performance of the whole body vibration by comparing the three cases.
2015-04-14
Journal Article
2015-01-1579
Jun Nakahara, Koji Yamazaki, Yusuke Otaki
Abstract In many cars, ride is less comfortable on smooth roads. This is because when the hysteresis in the suspension components rises steeply, the increase of the equivalent spring constant at small amplitude deteriorates the vibration isolation of the suspension. Therefore suspension components should be designed to prevent a steep rises in hysteresis. Investigating the influence of hysteresis, component models, which can reproduce such hysteresis characteristics, should be installed with model parameters in the vehicle model. Using conventional methods, these parameters can be accurately identified if measurement data is provided; however, it is difficult at the earlier phase of vehicle development. Then, if conflicting performances, such as ride and handling, are to be improved, both should be considered concurrently as early in a phase of vehicle development as possible and the design specifications for suspension components should be determined to satisfy both performances.
2015-04-14
Journal Article
2015-01-1597
Kazuto Yokoyama, Masahiro Iezawa, Hideyuki Tanaka, Keiichi Enoki
Abstract Mitsubishi Electric has developed a concept car “EMIRAI 2 xEV” that features an electric vehicle (EV) powertrain for safe, comfortable, eco-friendly driving experiences in the future. The vehicle was exhibited during the 2013 Tokyo Motor Show and the 2014 Automotive Engineering Exposition. The xEV is a four-wheel-drive EV with three motors: a water-cooled front motor and two air-cooled rear motors with integrated inverters. The 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 a built-in step down DC/DC converter, an EV control unit, a battery management unit, and electric power steering. All of the instruments are developed by Mitsubishi Electric. Motion control systems for the xEV have been developed based on our proprietary motor control technology.
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