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Viewing 241 to 270 of 9031
2015-04-14
Journal Article
2015-01-0226
Mahdi N. Ali
Abstract Bluetooth communication systems are constrained to use a low cost filtering technology, which requires designers to implement inexpensive noise reduction techniques. Improving Bluetooth sound and audio quality has been a topic of research over the years. Sound and audio quality in vehicles are areas that still require improvements in order to achieve better customer experience when using Bluetooth communication systems. This paper proposes a low cost, simple, and effective method to reduce noise in Bluetooth systems using Kalman Filtering. Our novel method is proposed to be used in vehicular Bluetooth applications. We have created a MATLAB/SIMULINK model to validate the proposed method. Results have demonstrated significant noise reduction and improvement to the processed speech signals.
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
Journal Article
2015-01-0660
Kosuke Sakamoto, Toshio Inoue
Abstract When a vehicle is in motion, noise is generated in the cabin that is composed of noise in multiple narrow-frequency bands and caused by input from the road surface. This type of noise is termed low-frequency-band road noise, and its reduction is sought in order to increase occupant comfort. The research discussed in this paper used feedback control technology as the basis for the development of an active noise control technology able to simultaneously reduce noise in multiple narrow-frequency bands. Methods of connecting multiple single-frequency adaptive notch filters, a type of adaptive filter, were investigated. Based on the results, a method of connecting multiple filters that would mitigate mutual interference caused by different controller transmission characteristics was proposed.
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
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
2015-01-1396
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
2015-01-1285
Dingfeng Deng, Fanghui Shi, Louis Begin, Isaac Du
Abstract Instances have occurred where the outer surface of turbocharger fully floating journal bearing bushings have exhibited damage from oil debris resulting in constant tone noise 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. 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 shows that oil debris particles in the outer film will reduce the speed ratio, while oil debris particles in inner film will increase the speed ratio. The tribology analysis also predicts the effects of oil debris on bearing stiffness and damping.
2015-04-14
Journal Article
2015-01-1309
Hyunggyung Kim
Abstract This Study describes about the development of new concept' rear wheel guards for the reduction of Road Noise in the passenger vehicles. The new wheel guards are proposed by various frequency chamber concept and different textile layers concept. Two wheel guards were verified by small cabin resonance and vehicle tests. Through new developing process without vehicle test, Result of road noise will be expected if this concepts and materials of wheel guard are applied into automotive vehicle. As this concept consider tire radiation noise frequency and multilayers sound control multilayers, 2 concepts reduced road noise from 0.5 to 1.0dB. The proposed method of part reverberant absorption is similar to results of vehicle tests by part absorption index. Furthermore, optimization of frequency band in wheel guards will reduce more 0.5 dB noises.
2015-04-14
Journal Article
2015-01-1329
Katsutomo Kanai, Hideki Katsuyama
Abstract A method of predictive simulation of flow-induced noise using computational fluid dynamics has been developed. The goal for the developed method was application in the vehicle development process, and the target of the research was therefore set as balancing the realization of a practical level of predictive accuracy and a practical computation time. In order to simulate flow-induced noise, it is necessary to compute detailed eddy flows and changes in the density of the air. In the research discussed in this paper, the occurrence or non-occurrence of flow-induced noise was predicted by conducting unsteady compressible flow calculation using large eddy simulation, a type of turbulence model. The target flow-induced noise for prediction was narrow-band noise, a type of noise in which sound increases in specific frequency ranges.
2015-04-14
Technical Paper
2015-01-1326
Sivanandi Rajadurai, Guru Prasad Mani, Kavin Raja, Sundaravadivelu Mohan
Abstract Generation of discretization with prescribed element sizes are adapted to the geometry. From the 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 hot end exhaust system, a bracket design plays 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
Journal Article
2015-01-0856
Martin Wissink, Rolf D. Reitz
Abstract Control of the timing and magnitude of heat release is one of the biggest challenges for premixed compression ignition, especially when attempting to operate at high load. Single-fuel strategies such as partially premixed combustion (PPC) use direct injection of gasoline to stratify equivalence ratio and retard heat release, thereby reducing pressure rise rate and enabling high load operation. However, retarding the heat release also reduces the maximum work extraction, effectively creating a tradeoff between efficiency and noise. Dual-fuel strategies such as reactivity controlled compression ignition (RCCI) use premixed gasoline and direct injection of diesel to stratify both equivalence ratio and fuel reactivity, which allows for greater control over the timing and duration of heat release. This enables combustion phasing closer to top dead center (TDC), which is thermodynamically favorable.
2015-04-14
Journal Article
2015-01-1147
Dongxu Li
Abstract A new approach for modeling and analysis of a transmission and driveline system is proposed. By considering the stiffness, damping and inertias, model equations based on lumped parameters can be created through standard Lagrangian Mechanics techniques. A sensitivity analysis method has then been proposed on the eigenspace of the system characteristic equation to reveal the dynamic nature of a transmission and driveline system. The relative sensitivity calculated can clearly show the vibration modes of the system and the key contributing components. The usefulness of the method is demonstrated through the GM 6-speed RWD transmission by analyzing the dynamic nature of the driveline system. The results can provide a fundamental explanation of the vibration issue experienced and the solution adopted for the transmission.
2015-04-14
Technical Paper
2015-01-1123
Jiangwu Zhang, Donghao Liu, Haisheng Yu
Abstract A novel single-mode compound split hybrid transmission with a compound planetary gear set and two brakes has been studied, which has more freedom of control to increase the system efficiency. System dynamics and matching performance of the driveline including a compound planetary gear set for a single-mode hybrid electric vehicle are numerically investigated. The multi-degrees of freedom torsional vibration model for the full-hybrid vehicle driveline with the power split device is established by MATLAB/Simulink. For comparison of the natural characteristic, eigenfrequencies and mode shapes are determined with the aid of a further simplified single-track mechanical model under different operation modes. Then, numerical simulations of dynamics and kinematics of the driveline and the compound planetary gear set are carried out.
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
2015-01-1122
Kengo Yabe, Toru Inagaki, Takashi Kondo
Abstract Seat vibration when a vehicle is idling or in motion is an issue in automobile development. In order to reduce this vibration, dynamic damper or inertia mass is widely used. These countermeasures increases vehicle's weight and causes bad fuel-efficiency. Some new ways to reduce the vibration without weight increase are needed. One of that is the floating seat. Seat vibration has been reduced by controlling seat resonance frequencies. In order to control resonance frequency, the structures of the seat-mounting unit are replaced with floating structures using rubber bushings. It was demonstrated that partially 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 caused by the fitting of rubber bushings to the seat-mounting unit was addressed using stopper structures optimized for each type of input.
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
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
2015-01-1195
Kiyotaka Maeda, Masashi Takahashi
Abstract To verify the appropriateness of the vibration test conditions of ISO 12405, we performed tailoring to derive power spectrum densities and test durations as vibration test conditions. Vehicles used for tailoring included two electric vehicles and one plug-in hybrid electric vehicle. Those vehicles were equipped with accelerometers and were run on seven different road types at different speeds while data on the acceleration of the battery packs 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 accelerations were obtained, confirming that they are appropriate. However, both experiments and theory suggest that the test duration for the Z-axis exceeds those of the X- and Y-axes.
2015-04-14
Technical Paper
2015-01-1360
Sajjad Beigmoradi
Abstract Improvements of aerodynamics and wind noise are two important objectives for automotive engineers. Improvement of aerodynamics behavior and the reduction of wind noise have been always greatly concerned by automotive engineers since they negatively affect passengers comfort, fuel consumption, car performance and, stability. In this paper, optimum levels of four dominant rear shape parameters for a simplified car model are investigated considering drag coefficient and aerodynamic noise objectives. C-Pillar angle, trunk angle, boat tail angle and rear box length are considered as variable parameters. Taguchi method is used for finding aerodynamic and acoustic optimum levels. Numerical simulation for base case is compared with experimental results in the literature. Numerical results show good agreement with experimental test. Afterwards, optimum levels for parameters regarding objectives are calculated using Taguchi method.
2015-04-14
Technical Paper
2015-01-1665
Nicolas Arnault, Adrien Baudet, Nicolas Becker
Abstract Noise is one of the key nuisances from which the car is the source. One of those noise sources, the air induction line of the Internal Combustion Engine (ICE), can use some noise attenuation systems as damping isolated volumes (called resonators), or porous ducts, before the air filter. Those solutions can attenuate designated frequencies or range of frequencies. The issue is that those solutions can be bulky, especially for resonators, expensive or even generate some drawbacks on performances. Elements like hot air ingestion, pressure drops or even generation of new noises are some significant areas where performances can be deteriorated through the implementation of such acoustic device on the air induction line. It has then invented and developed a brand new type of acoustic device, designed to ensure optimal performances for a very low packaging. This solution preserves performances and cost, and tend to cope with most of the drawbacks of usual technologies.
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
Journal Article
2015-01-0796
Stephen Busch, Kan Zha, Paul C. Miles, Alok Warey, Francesco Pesce, Richard Peterson, Alberto Vassallo
Abstract A pilot-main injection strategy is investigated for a part-load operating point in a single cylinder optical Diesel engine. As the energizing dwell between the pilot and main injections decreases below 200 μs, combustion noise reaches a minimum and a reduction of 3 dB is possible. This decrease in combustion noise is achieved without increased pollutant emissions. Injection schedules employed in the engine are analyzed with an injection analyzer to provide injection rates for each dwell tested. Two distinct injection events are observed even at the shortest dwell tested; rate shaping of the main injection occurs as the dwell is adjusted. High-speed elastic scattering imaging of liquid fuel is performed in the engine to examine initial liquid penetration rates.
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
2015-01-0212
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
Journal Article
2015-01-1667
Yasunori Kanda, Tsunehiro Mori
Abstract It has been required recently that diesel engines for passenger cars meet various requirements, such as low noise, low fuel consumption, low emissions and high power. The key to improve the noise is to reduce a combustion noise known as “Diesel knock noise”. Conventional approaches to reduce the diesel knock are decreasing combustion excitation force due to pilot/pre fuel injection, adding ribs to engine blocks or improving noise transfer characteristics by using insulation covers. However, these approaches have negative effects, such as deterioration in fuel economy and increase in cost/weight. Therefore, modification of engine structures is required to reduce it. We analyzed noise transfer paths from a piston, a connecting rod, a crank shaft to an engine block and vibration behavior during engine operation experimentally, and identified that piston resonance was a noise source.
2015-04-14
Journal Article
2015-01-0662
Weiguo Zhang, Mac Lynch, Robert Reynolds
Abstract A turbocharger is currently widely used to boost performance of an internal combustion engine. Generally, a turbocharger consists of a compressor which typically is driven by an exhaust turbine. The compressor will influence how the low frequency engine pulsation propagates in the intake system. The compressor will also produce broad-band flow induced sound due to the turbulence flow and high frequency narrowband tonal sound which is associated with rotating blade pressures. In this paper, a practical simulation procedure based on a computational fluid dynamics (CFD) approach is developed to predict the flow induced sound of a turbocharger compressor. In the CFD model of turbocharger compressor, the unsteady, moving wheel, detached eddy simulation (DES) approach are utilized. In this manner, both the broad-band and narrow-band flow induced sound are directly resolved in the CFD computation.
2015-04-13
Article
The Ohio State University student team revealed the vehicle it will use to try to break its own world land speed record—307 mph—with an over 400-mph mark. The 38-ft-long (11.6-m) vehicle contains 2000 A123 pouch cells and runs a four-wheel-drive system with two motors design-rated at 3000 hp (2238 kW).
2015-03-31
Article
Gill Sensors & Controls offers the GScondition monitoring sensor range family to reduce unplanned breakdowns in industrial machine applications.
2015-03-30
Technical Paper
2015-01-0108
Qingdong Hou, Wenjie Qin, Zhe Yu, Mu Tang, Yang Ran
Abstract With the increasing of people's demand for comfort of vehicles, the noise generated by the reverse of windshield wiper causes wide attention. In this paper, as the front windshield wiper of one car is considered, the impacts of the preload of wiper lever spring, the torsional stiffness of blade neck and the flexible connection between the wiper arm and the wiper lever on the vibration excitation applied to the front windshield are analyzed based on the multi-body dynamic model of wiper system. The dynamic model includes the crank pivot, the four linkage mechanism, the wiper blades, the wiper arms and the windscreen glass which has been established considering with elastic contact between the wiper blade and the front windshield. Based on the analysis results the dimensions of cross-section of the wiper blade rubber and the flexible connection between the wiper arm and the wiper lever are designed to reduce the quick-return impact of wiper lever.
2015-03-30
Technical Paper
2015-01-0107
Sunny Narayan
Abstract Analysis of noise level from engines is important from point of view of customer satisfaction. Accurate prediction of noise is important for planning, design and target setting decisions for meeting customer satisfaction goals. In this work an analytic model has been described to break diesel engine noise data into various components in order to plan a strategy for condition monitoring of engine.
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