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Viewing 241 to 270 of 7641
2016-04-05
Technical Paper
2016-01-1317
Peng Wang, Xin Hua, T. Wu, David W. Herrin
Abstract Insertion loss in one-third or octave bands is widely used in industry to assess the performance of large silencers and mufflers. However, there is no standard procedure for determining the transmission loss in one-third or octave bands using measured data or simulation. In this paper, assuming that the source is broadband, three different approaches to convert the narrowband transmission loss data into one-third and octave bands are investigated. Each method is described in detail. To validate the three different approaches, narrowband transmission loss data of a simple expansion chamber and a large bar silencer is converted into one-third and octave bands, and results obtained from the three approaches are demonstrated to agree well with one another.
2016-04-05
Technical Paper
2016-01-1311
Tsuyoshi Kanuma, Katsumi Endo, Fumiaki Maruoka, Hiroshi Iijima, Makoto Kawamura, Keisuke Nakazawa, Eiki Yanagawa
Abstract 1 The vane-type rotary compressor of a heating, ventilating, and air conditioning system (HVAC system) is simple and compact but may emit noise due to the collision between the vanes and the cylinder wall. Several studies have been conducted on this chattering noise, with a focus on the noise associated with the compressor revolution speed, temperature, suction pressure, and exhaust pressure. However, such investigations are not sufficient to reveal the behavior of the vane movement in its entirety. To minimize the chattering noise, the details of the mechanism of such vane-operating noise must be investigated by analyzing the behavior of the vanes as a function of time. The vanes move according to the balance between the front and rear pressures. This report describes a novel visualization technique with which to monitor the motion of a vane under given operating conditions. In addition, a method of measuring the pressure affecting the movement of the vanes is discussed.
2016-04-05
Technical Paper
2016-01-1378
Takanori Ide, Kentaro Toda, Yasunori Futamura, Tetsuya Sakurai
Abstract Efficient method to solve large-scale eigenvalue problem in vibration is presented. NVH (Noise, Vibration and Harshness) performance is an important quality measure of vehicles. Therefore, the reduction of vibration is one of the key considerations of new automatic transmission design. In addition, reduction of product design time is another important requirement. Computer Aided Engineering (CAE) is becoming a more important methodology to reduce product design time. However, computational time of eigenvalue problem takes long. We propose parallel eigenvalue computation (Sakurai-Sugiura method) for large-scale eigenvalue problems. This method has a good parallel scalability according to a hierarchical structure of the method. As the demonstrative problem, we consider large-scale computation of eigenvalue problem for AISIN AW FWD automatic transmission.
2016-04-05
Technical Paper
2016-01-1430
Se Jin Park, Murali Subramaniyam, Seoung Eun Kim, Tae Hyun Kim, Hee Su Sin, Dong Hag Seo, Hyu Hyeong Nam, Jeong Cheol Lee
Abstract Seating comfort is associated with the various factors, and one of the principal components of a vehicle environment which can affect passenger’s comfort is vibration. The seat design plays a vital role in the vibration isolation. In recent years, automotive seat designers are paying more attention for the improvement of seat cushion properties. This paper provides information about a new automotive seat concept that use double-wall 3D air-mat in cushion along with foam cushion in the seat cushion system. To test the developed seat on vibration isolation characteristics, seating comfort, and ride quality experiments have been performed. This research is divided into two parts. At first, the newly developed seat tested on the motion simulator. In study 2, road tests were performed on the national highway. Two tri-axial accelerometers were used to measure acceleration at the foot and hip in two different seats (seat with and without double-wall 3D air-mat).
2016-04-05
Technical Paper
2016-01-1348
Kenichi Higuchi, Fumihiko Toyoda, Hirohito Terashima, Shinji Ikeda, Eitaku Nobuyama
Abstract 1 There are two design challenges of the flow path switching valve in a three-stage variable discharge oil pump. The first is to obtain the required discharge pressure characteristics and the other is to prevent hydraulic vibration. Therefore, we established technologies to determine the shape of the valve and the valve housing that resolve these two challenges. The technology to obtain the required discharge pressure characteristics solves equations that are statically true, such as the equations for the equilibrium of forces and hydraulic orifice. The hydraulic vibration control technology derives a differential equation that takes transient behavior, including oil elasticity and inertia, into account first. Then, the derived equations are converted to a transfer function that indicates the valve behavior according to the input of oil pressure changes. And then the stability criterion is applied to judge whether hydraulic vibration occurs or not.
2016-04-05
Technical Paper
2016-01-1355
Jeffrey R. Hodgkins, Walter Brophy, Thomas Gaydosh, Norimasa Kobayashi, Hiroo Yamaoka
Abstract Current vehicle acoustic performance prediction methods, CAE (computer aided engineering) or physical testing, have some difficulty predicting interior sound in the mid-frequency range (300 to 1000 Hz). It is in this frequency range where the overall acoustic performance becomes sensitive to not only the contributions of structure-borne sources, which can be studied using traditional finite element analysis (FEA) methods, but also the contribution of airborne noise sources which increase proportional to frequency. It is in this higher frequency range (>1000 Hz) that physical testing and statistical CAE methods are traditionally used for performance studies. This paper will discuss a study that was undertaken to test the capability of a finite element modeling method that can accurately simulate air-borne noise phenomena in the mid-frequency range.
2016-04-05
Technical Paper
2016-01-1361
Abhijit Londhe, Vivek Yadav, SenthilKumar Kannaiyan, Krishnan Karthikeyan, Ganeshan Reddy
Abstract Reducing the vibrations in the drivetrain is one of the prime necessities in today’s automobiles from NVH and strength perspectives. The virtual drivetrain simulation methodology to predict the driveline induced excitations transmitted to vehicle is developed for three cylinder engine using Adams View. The obtained mount forces from Adams dynamic simulation is correlated with the measured test data at vehicle level and the good correlation is observed. Paper discusses on the methodology of virtual drivetrain using Adams view and the correlation of measured dynamic mount forces with simulation results. This correlation gives the confidence that the developed simulation methodology can be used to get the mount forces of different orders from drivetrain.
2016-04-05
Technical Paper
2016-01-1186
Dong Hao, Yongping Hou, Jianping Shen, Liying Ma
Abstract The vehicular fuel cell stack is unavoidably impacted by the vibration in the real-world usage due to the road unevenness. However, effects of vibration on stacks have yet to be completely understood. In this work, the mechanical integrity and gas-tightness of the stack were investigated through a strengthen road vibration test with a duration of 200 h. The excitation signals applied in the vibration test were simulated by the acceleration of the stack, which were previously measured in a vehicle vibration test. The load signals of the vehicle vibration test were iterated through a road simulator from vehicle acceleration signals which were originally sampled in the proving ground. Frequency sweep test was conducted before and after the vibration test. During the vibration test, mechanical structure inspection and pressure maintaining test of the stack were conducted at regular intervals.
2016-04-05
Technical Paper
2016-01-0871
Sanjoy Biswas, Manish Bakshi, G Shankar, Achintya Mukhopadhyay
Abstract An emissions, combustion noise and performance study were conducted to explore the effects of two different multiple injections strategies on emissions, combustion noise and performances without altering EGR %. The experiments were done on a six cylinder inline CRDI diesel production engine. The aim of this study is to improve performances (brake specific fuel consumption [BSFC], torque) and combustion noise (reduction) using multiple injection strategies without violating emission regulations. The other objective of this carried-out analysis is to examine the influence of different operating parameters (Speed and Load) and main injection timing combined, on same multiple injection strategies (Pilot- main – after {PMA}and Early - pilot- main –after {EPMA}) by means of analyzing emissions/soot, combustion noise and performances data.
2016-04-05
Technical Paper
2016-01-1061
Guiping Yue, Wenbo Niu, Jian Zhao, Dandan Kong, Yun Li, Hangsheng Hou
Abstract Gear whine noise impacts customer perception of vehicle interior quietness in general and sound quality in particular. It has been a frequently occurred annoying phenomenon during vehicle development and much discussed topic regarding transmission NVH refinement in automotive industry. This work pertains to a transmission gear whine issue encountered in prototype evaluations during a vehicle program development process. The effort centers itself on the optimization of transmission gear macroscopic and microscopic parameters to fix the issue which is deemed unacceptable for customers. Specifically, by using multi-body dynamics approach, this work carries out a transmission system whine noise simulation based on optimal gear macro parameter selection and micro tooth flank modification. The obtained results show that the proposed design changes could successfully resolve the issue, which is verified by subsequent test measurement and confirmed by subjective evaluations.
2016-04-05
Technical Paper
2016-01-1393
Prabhakar Konikineni, V. Sundaram, Kumar Sathish, Sankarasubramanian Thirukkotti
Abstract Fan shroud is one of the critical components in an engine cooling system. It helps in achieving optimum air flow across the heat exchangers. The major challenge is to design a fan shroud which meets noise, vibration and harshness (NVH) requirements without compromising on air flow targets [1]. An improperly designed fan shroud will cause detrimental effects such as undesirable noise and vibration, which will further damage the surrounding components. In current days, multiple simulations and test iterations are carried out in order to optimize its design. The objective of this paper is to provide a design framework to achieve optimized fan shroud that meets NVH requirements in quick turnaround time using Design for Six Sigma (DFSS) approach [2]. The purpose of the Engine cooling system is to maintain the coolant temperature across the vehicle.
2016-04-05
Technical Paper
2016-01-0513
Yohei Miki, Hisao Futamata, Masahiko Inoue, Masashi Takekoshi, Kohbun Yamada
Abstract Unexpected noise may occur around air intake manifold when the throttle valve is quickly opened. In order to solve this problem, mesh is often mounted into the air flow between the intake manifold and the throttle body. In this study the effect of mesh design on the noise reduction was investigated. Several designs of the mesh were tested with an actual automobile and the developed test equipment taking advantage of an intake manifold unit, and the noise attenuation was discussed with measuring the noise and observation of the mesh deformation. Based on those experiments, the mesh design for noise reduction was optimized. Furthermore integration of mesh and rubber gasket was examined. Finally, rubber mesh-gaskets which provide sealing and noise attenuation for air intake has been proposed in this study.
2016-04-05
Technical Paper
2016-01-0249
Balashunmuganathan Vasanth, Kumar Sathish, Murali Govindarajalu, Mohsin Khan
In recent years reducing the automobile HVAC (Heating Ventilation and automobile conditioning) noise inside the vehicle cabin is one of the main criterions for all OEMs to provide comfort level to the passengers. The primary function of the HVAC is to deliver more air to the cabin with less noise generation for various blower speeds. Designing the optimum HVAC with less noise is one of the major challenges for all automotive manufacturers and HVAC suppliers. During the design stage, physical parts are not available and hence the simulation technique helps to evaluate the noise level of HVAC. In this study, a computational 1D (one dimensional) analysis is carried out to compute the airflow noise originated from the HVAC unit and propagated to the passenger cabin. Modeling has been done using unigraphics and the analysis is carried out using the commercial 1D software GT suite.
2016-04-05
Technical Paper
2016-01-0517
Kentaro Kimura, Ryoji Habuchi, Tetsuya Kono, Tadashi Mori, Kaname Arimizu
Abstract To reduce cabin noise and vehicle weight (for lower fuel consumption), a lightweight soundproofing cover was developed as a countermeasure to sources of noise, using the Biot theory (vibration propagation theory in poroelastic materials). This report also presents the results of its application to a metal belt-type continuously variable transmission (CVT) used in Toyota Motor Corporation’s 2.0L vehicles.
2016-04-05
Technical Paper
2016-01-1294
Jonggyu Kim, Pyoung Beom Kim, YoungChan Lee, Sunghee Jung, Byeong-Ug Choi
Abstract This study presents the NVH characteristics of a passenger vehicle with a three-cylinder engine and a Continuously Variable Transmission (CVT) and an optimization procedure to achieve balance between fuel economy and NVH. The goal of this study is to improve fuel economy by extending the lock-up area of the damper clutch at low vehicle speed and to minimize booming noise and body vibration caused by the direct connection of the engine and transmission. Resonance characteristics of the chassis systems and driveline have been studied and optimized by the experiment. NVH behavior of the vehicle body structure is investigated and modifications for refinement of booming and body vibration are proposed by simulation using MSC NASTRAN. Calibration parameters for CVT control are optimized for fuel economy and NVH.
2016-04-05
Technical Paper
2016-01-1300
Jacob Milhorn, Vincent Rovedatti, Richard DeJong, Gordon Ebbitt
Abstract Road tests on a pickup truck have been conducted to determine the acoustic loads on the back panel surfaces of the vehicle. Surface mounted pressure transducers arrays are used to measure both the turbulent flow pressures and the acoustic pressures. These measurements are used to determine the spatial excitation parameters used in an SEA model of the transmission loss through the back panel surfaces. Comparisons are made between tests on different road surfaces and at different speeds to identify the relative contributions of acoustic and wind noise.
2016-04-05
Technical Paper
2016-01-1432
Alexander Siefert
Abstract Predicting the vibration comfort is a difficult challenge in seat design. There is a broad range of requirements as the load cases strongly vary, representing different excitation levels, e.g. cobblestones or California roads. Another demand is the driver expectation, which is different for a pickup and a sports car. There are several approaches for assessing the vibrations of occupants while driving. One approach is the evaluation of comfort by integral quantities like the SEAT value, taking into account a weighting based on the human body sensitivity. Another approach is the dimension of perception developed by BMW, which is similar to psychoacoustics as the frequency range is separated with respect to occurring vibration phenomena. The seat transmissibility is in the focus of all activities. In the frequency range it defines the relation between the input at the seat slides and the output at the interface of human body and trim.
2016-04-05
Technical Paper
2016-01-1680
Suresh Abasaheb Patil, Indrajit Dinkar More
Abstract This paper incorporates the on-road real time ride comfort testing and simulation analysis of the typical passenger cars. The main objective is to analyze the vibrations to the passenger’s seat through the irregularities on road surface. This analysis is carried out with the help state-of-the-art of FFT analyzer for different classes of passenger car for variety of road conditions which have been validated by simulation analysis in the 20-Sim simulation software.
2016-04-05
Technical Paper
2016-01-0273
Richard DeJong, Se Ge Jung, John Van Baren
Abstract Methods for conducting accelerated vibration fatigue testing of structures, such as MIL-STD-810G, allow for the non-linear scaling of the test time with the inverse of the rms vibration amplitude based on the slope of the material S-N curve obtained from cyclic fatigue tests. The Fatigue Damage Spectrum (FDS) is used as a method to allow for different level scalings at different frequencies in a broadband vibration environment using the relative responses of resonances in the structure. A recent development in industry has been to mix impulses with random excitations to increase the vibration peak levels (as measured by the kurtosis), thereby accelerating the fatigue even more than would occur with a Gaussian excitation. This paper presents results from a study to determine the conditions under which high kurtosis, impulsive excitations actually produce high kurtosis responses in structural resonances thus increasing the level of the FDS.
2016-04-05
Technical Paper
2016-01-0411
Yosuke Akita, Kenji Abe, Yoshihiro Osawa, Yoshitsugu Goto, Yuji Nagasawa, Noboru Sugiura, Satoshi Wakamatsu, Kyoko Kosaka
Abstract If a vehicle is left in a humid environment, the coefficient of friction between the brake pads and discs increases, generating a discomforting noise during braking called brake squeal. It is assumed that this increase in the coefficient of friction in a humid environment is the effect of moisture penetrating between the brake friction surfaces. Therefore, this paper analyzes the factors causing coefficient of friction variation with moisture between the friction surfaces by dynamic observation of these surfaces. The observation was achieved by changing the disc materials from cast iron to borosilicate glass. One side of the glass brake disc was pushed onto the brake pad and the sliding surface was observed from the opposite side by a charge coupled device (CCD) camera. First, a preliminary test was carried out in a dry state using two pad materials with different wear properties to select the appropriate pad for observing the friction surfaces.
2016-04-05
Technical Paper
2016-01-0488
Takashi Izawa, Motohiko Koushima
Abstract In order to determine the seizure limit of the main bearings of passenger vehicles under actual operating conditions, evaluations were conducted in environments containing noise factors (Various factors which designer cannot adjust and which make function vary were defined as noise factors in this paper.) [1,2] It was shown that noise factors have an effect on seizure limit performance in relation to performance under ideal test conditions (test conditions in which no noise is present). In relation to oil properties, the results showed that a reduction in viscosity as a result of dilution affected seizure limit performance. In relation to the shape of the sliding sections of the test shaft, seizure limit performance declined in a shaft in which the central section was swollen (“convex shaft” below).
2016-04-05
Technical Paper
2016-01-1044
Toshiaki Kobayashi
Abstract This paper describes the establishment of a new method for predicting piston skirt scuffing in the internal combustion engine of a passenger car. The authors previously constructed and reported a method that uses 3D piston motion simulation to predict piston slap noise and piston skirt friction. However, that simulation did not have a clear index for evaluation of scuffing that involves piston skirt erosion, and it impressed shortage of the predictive accuracy of a scuffing. Therefore, the authors derived a new evaluation index for piston skirt scuffing by actually operating an internal combustion engine using multiple types of pistons to reproduce the conditions under which scuffing occurs, and comparing with the results of calculating the same conditions by piston motion simulation.
2016-04-05
Technical Paper
2016-01-1069
Masayoshi Otaka, Taro Kasahara, Kenichi Komaba
Abstract As a means of further improving combustion efficiency of gasoline engine, an increase in compression ratio, which enhances the risk of knocking, is thinkable. To optimize engine combustion parameters, a technology that can precisely detect knocking is desirable. Presently skillful experts have been evaluating knocking subjectively by listening to radiation noise so far. The authors developed a device that can precisely detect knocking by means of processing sound signals, which are captured by a high-performance microphone that is sensitive in the wide frequency range. Shock waves induced by knocking cause in-cylinder gas vibrations that emits metallic hit noises from the outer engine wall. We studied how to identify the feature values of frequency characteristics when knocking occurs, under the assumption that the engine radiation noise includes more than 2nd-order harmonic components with respect to the basic frequency of the in-cylinder gas vibration mode.
2016-04-05
Technical Paper
2016-01-1123
Ante Bozic
Abstract Among the various types of hydrostatic transmissions, those based on radial piston multi-stroke machines are well-known solutions for off-road mobile machines. The balance between compactness, efficiency, control, comfort and price is the main reason for this. For the same reason, several car companies have tried to introduce hydrostatic transmissions into on-road applications. All such efforts have failed, mainly due to the whine noise produced by the hydrostatic machines. In particular, well-known standard solutions that aim to address the noise of radial piston multi-stroke machines, such as optimized relief grooves known as ‘notches’, are oriented toward reduction of the noise level. Unfortunately, the remaining whine noise, even with well-optimized notches, is unacceptable for automotive NVH standards.
2016-04-05
Technical Paper
2016-01-1128
Bo Peng, Tao Liu, Sifa Zheng, Xiaomin Lian
Abstract Neutral-idle strategy has been applied for years to improve the fuel consumption of automatic transmission cars. The updated demand is the use of expanded slipping control strategy for further improvement of the transmission efficiency and response speed. However, one major drawback of the continuous slipping clutches is the high tendency to produce shudder or low frequency variation. In this research, a special neutral-idle shudder phenomenon is presented. This special shudder is not only related to slipping clutches but also related to the vibration and structure of the powertrain system. Simulations and experiments are conducted to give an insight view of this phenomenon. The analysis reveals that this special shudder is caused by both torsional vibration of the driveline and rigid-body vibration of the powertrain system. A positive feedback loop between those two kinds of vibrations leads to this special neutral-idle shudder.
2016-04-05
Technical Paper
2016-01-1114
Jinsung Kim
Abstract A dry clutch induces judder phenomenon which is caused by variations in the vehicle load condition and frictional material properties. Such a problem may lead to the stick-slip limit cycle that results in undesired longitudinal vibrations of vehicles. To solve this problem, a vibration suppression control is proposed. The amplitude of vibrations is detected by the signal conditioning from the measurements with the transmission input shaft speed and the wheel speed sensors. Based upon this, a perturbation torque is applied additionally on the nominal launch controller to make the drive shaft oscillation vanish. It can be achieved by the control design without any extra hardware cost. Finally, experimental results confirm the effectiveness of the proposed mechanism.
2016-04-05
Technical Paper
2016-01-1320
Sri Siva Sai Meduri, V. Sundaram, Sathish Kumar S
Abstract The Air Induction system (AIS) must provide sufficient and clean air to the engine for its desired combustion thus enhancing engine performance. The critical functions which effect the performance are pressure restriction and acoustic performance. The ideal design of AIS effectively reduces the engine noise heard at snorkel, which contributes to the cabin noise. Good acoustic expertise and several tests are required to optimize the design of AIS. Multiple resonators are commonly used in passenger cars to attenuate the noise. This paper emphasize on One Dimensional (1D) approach to optimize the resonators in the AIS to meet the functional requirements. In AIS, the flow happens from the snorkel to the engine air intake whereas the engine noise propagates in the opposite direction. The unsteady mass flow through the intake valves causes pressure fluctuations in the intake manifold and these propagate to intake orifice and are radiated as noise which is heard at snorkel.
2016-04-05
Technical Paper
2016-01-1295
Atsushi Itoh, ZongGuang Wang, Toshikazu Nosaka, Keita Wada
Abstract Without engine noise, the cabin of an electric vehicle is quiet, but on the other hand, it becomes easy to perceive refrigerant-induced noise in the automotive air-conditioning (A/C) system. When determining the A/C system at the design stage, it is crucial to verify whether refrigerant-induced noise occurs in the system or not before the real A/C systems are made. If refrigerant-induced noise almost never occurs during the design stage, it is difficult to evaluate by vehicle testing at the development stage. This paper presents a 1D modeling methodology for the assessment of refrigerant-induced noise such as self-excitation noise generated by pressure pulsation through the thermal expansion valve (TXV). The GT-SUITE commercial code was used to develop a refrigerant cycle model consisting of a compressor, condenser, evaporator, TXV and the connecting pipe network.
2016-04-05
Technical Paper
2016-01-1319
Kimitoshi Tsuji, Katsuhiko Yamamoto
Abstract It is important for vehicle concept planning to estimate fuel economy and the influence of vehicle vibration using virtual engine specifications and a virtual vehicle frame. In our former study, we showed the 1D physical power plant model with electrical starter, battery that can predict combustion transient torque, combustion heat energy and fuel efficiency. The simulation result agreed with measured data. For idling stop system, the noise and vibration during start up is important factor for salability of the vehicle. In this paper, as an application of the 1D physical power plant model (engine model), we will show the result of analysis that is starter shaft resonance and the effect on the engine mount vibration of restarting from idle stop. First, an engine model for 3.5L 6cyl NA engine was developed by energy-based model using VHDL-AMS. Here, VHDL-AMS is modeling language registered in IEC international standard (IEC61691-6) to realize multi physics on 1D simulation.
2016-04-05
Technical Paper
2016-01-1313
Brian Pinkelman, Woo-Keun Song
Abstract Most methods of vibration analysis focus on measuring the level of vibration. Some methods like ISO-2631 weigh vibration level based on human sensitivity of location, direction, and frequency. Sound can be similarly measured by sound pressure level in dB. It may also be weighted to human frequency sensitivity such as dBA but sound and noise analysis has progressed to measure sound quality. The characteristic and the nature of the sound is studied; for example equal or near equal sound levels can provide different experiences to the listener. Such is the question for vibration; can vibration quality be assessed just as sound quality is assessed? Early on in our studies, vibration sensory experts found a difference in 4 seats yet no objective measurement of vibration level could reliably confirm the sensory experience. Still these particular experiences correlated to certain verbal descriptors including smoothness/roughness.
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