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2016-04-05
Technical Paper
2016-01-0431
Guangqiang Wu, Huwei WU, Xiang Chen
During the process of vehicle creeping, severe vibro-impacts of unloaded or lightly loaded gear pairs in a manual transmission may occur in the powertrain system due to some nonlinear characteristics. Multi-staged stiffness clutch damper, as a main nonlinear component, could have a great influence on powertrain system torsional vibration performance. So a mass-production passenger sedan is taken as the research subject and the nonlinear characteristics impact of multi-staged stiffness clutch damper for vehicle creeping vibration is investigated by using lumped-parameter modeling method. Firstly, a quasi-transient model of an inline four-cylinder and four-stroke engine, based on measured data of cylinder gas pressure versus crankshaft angle, is derived. Effective output torque is achieved and as the input excitation to the driveline. Secondly, a 12 DOFs (Degrees of Freedom) nonlinear and branched torsional vibration model is established.
2016-04-05
Technical Paper
2016-01-1378
TAKANORI IDE, Kentaro TODA, Yasunori Futamura, Tetsuya Sakurai
Efficient method to solve large-scale eigenvalue computation in vibration is presented. NVH(Noise, Vibration and Harshness) performance is an important quality measure of the vehicle. Therefore the reduction of vibration is one of the key considerations of new automatic transmission design. In addition, accelerating product design time is another important issue. Computer Aided Engineering (CAE) is becoming a more important methodology to reduce product design time. However computational time of eigenvalue problem takes a 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 a demonstrative problem, we consider large-scale eigenvalue computation of the AISIN AW FWD automatic transmission.
2016-04-05
Technical Paper
2016-01-1063
George Nerubenko
Up to 30% of engine noise is delivered by front end pulley combined with torsional vibration damper, and technically it is the main contributor to recorded engine noise level. So the novel solutions in terms of improving the design and performance of torsional vibration damper would help to reduce radically this component of engine noise. The results of dynamical study of patented torsional vibration damper combined with pulley are presented. Design and structure of torsional vibration damper is based on author’s US Patent 7,438,165 having the self-tuning control system for all frequencies in running engine in all operational regimes. Mathematical model has been used for the analysis of the emitting noise of engine having proposed torsional vibration damper. Attention is paid to mitigation of the sound power levels contributing by engine subsystem “end of crankshaft - torsional vibration damper – pulley”.
2016-04-05
Technical Paper
2016-01-1058
Naoki Toyama, Takashi Hoshi
This paper reports on technology for suppressing forced vibration of the multiplate wet clutch used in the automatic transmission of recently released hybrid automobiles. This study constructed technology for predicting forced vibration due to the clutch structure by 3-D Simulation model, and estimated the vibration modes that would occur. Next, running modes with severe forced vibration were extracted using a drivetrain torsional vibration by 1-D Simulation model from the engine to the driveshaft and the vibration target values estimated from the body. These results were used to change to a clutch structure that has sufficient margin with respect to the forced vibration targets and to appropriately adjust the running modes. It was then confirmed using an actual vehicle that forced vibration does not occur in the running mode estimated to have the most severe forced vibration.
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
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 as it is directly in contact with human body. Vibration isolation properties of a seat depend upon its dynamic parameters such as cushion, spring stiffness, and damping of seat suspension. 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 which use double-wall 3D air mat in cushion along with foam cushion. The air-mats base fabrics are interlinked with numerous spacer threads to make a 3D structure. An optimization-based method is used to determine the optimal seat dynamic parameter for cushion (particularly for double-wall 3D air mat) based on minimizing occupant’s body discomfort.
2016-04-05
Technical Paper
2016-01-1348
Kenichi Higuchi, Fumihiko Toyoda, Hirohito Terashima, Shinji Ikeda, Eitaku Nobuyama
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. Then, the equation is 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
2016-01-0443
Han Zhang, Gang Li, Yu Wang, Yuchuan Gu, Xiang Wang, Xuexun Guo
A vehicular hydraulic electrical energy regenerative semi-active suspension(HEERSS) was presented, and its working principle and performance were analyzed. Firstly, configuration and working principle of the HEERSS were described; Secondly, kinetic equation of HEERSS was deduced, and a skyhook controller was designed for HEERSS. The traditional skyhook control strategy should be changed for the characteristic of HEERSS, because the damping force during extension stroke could be controlled, but not in compression stroke. Thirdly, the performance of HEERSS was compared with passive suspension(PS), traditional semi-active suspension(TSS). The simulation results showed that in the vehicle body resonance frequency and tire resonance frequency, the amplitude of suspension index parameters ranked in a descend order were PS, HEERSS and TSS; but in the transition frequency band, the amplitude of suspension index parameters ranked in a descend order were. TSS, HEERSS and PS.
2016-04-05
Technical Paper
2016-01-1432
Alexander Siefert
A particular challenge in the development of passenger cars is within prognosis of the vibration comfort. The range of requirements is broad as the excitation varies between cobblestones up to California roads. A further demand is the driver expectation which is different for a pickup or for a sports car. There exist several approaches for assessing the vibrations of occupants while driving. On the one side the comfort is evaluated by integral quantities as 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 appearing vibration phenomena. In the centre of all activities is the seat transmissibility in the frequency range, describing 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
2016-01-1296
Yuntao Cao, Dengfeng Wang, Tonghang Zhao, Xining Liu, Chao Li, Hangsheng Hou
The source of noise excitation is different between electric and conventional vehicles due to their distinctive power system architecture. This work focuses on an interior noise contribution analysis using a model established base on the noise path analysis principle. The obtained results show that the structural-borne noise from the road excitation acts as a major contributor to the overall interior noise level, and the structural-borne noise from the powertrain system contributes noticeably as well, whereas the contribution from the electric motor and tire is relatively insignificant.
2016-04-05
Technical Paper
2016-01-1317
Peng Wang, Xin Hua, T Wu, David W. Herrin
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 proposed. Each method is described in detail. To validate the three proposed approaches, narrowband transmission loss of a simple expansion chamber is converted into one-third and octave bands, and results obtained from the suggested approaches are demonstrated to agree well with one another.
2016-04-05
Technical Paper
2016-01-1295
Atsushi Itoh, ZongGuang wang, Toshikazu Nosaka, Keita Wada
Electric vehicle has quiet in the cabin, but on the other hand, it becomes easy to perceive refrigerant-induced noise in automotive air-conditioning system. In the case of purchasing air-conditioning components from some suppliers separately, it is crucial to verify whether refrigerant-induced noise occurs in system or not before air-conditioning components are assembled. If target noise occurs less frequently, it is difficult to evaluate in a vehicle testing. This paper presents 1D modeling methodology for simulation of refrigerant-induced noise such as self-excitation noise generated by pressure pulsation through thermal expansion valve. A GT-SUITE commercial code was used to develop a refrigerant cycle model, consisting of compressor, condenser, evaporator, thermal expansion valve and connecting pipe network.
2016-04-05
Technical Paper
2016-01-1319
Kimitoshi Tsuji, Katsuhiko Yamamoto
It is important for vehicle concept planning to estimate fuel economy and the influence of vehicle vibration in advance 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 simulated 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, 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. The power plant was 3.5L 6cyl NA. The power plant model was realized by energy based model using VHDL-AMS. Here, VHDL-AMS is modelling language stored in IEC international standard (IEC61691-6) and can realize multi physics on 1D simulation.
2016-04-05
Technical Paper
2016-01-1057
Masaya Miyazawa, Kei Mochizuki, Kondo Takashi
To achieve lightweight, low friction and fuel efficient engine, the crankshaft is required to be designed lightweight, small-diameter shaft, long stroke. In this case, vibration of the crankshaft is increased by reduction of shaft stiffness. The conventional way of dealing with this increased vibration used to be to add an inertia mass ring or a double mass damper. Such an approach, however, increases weight, making the balance of weight reduction and vibration reduction less readily achieved. This paper reports on a method of reducing crankshaft vibration without increasing weight by tuning the shape of the crankshaft damper pulley hub. The main factors of the crankshaft vibration increase were investigated that it is coupled mode of the crankshaft bending and the crankshaft damper pulley bending. This was ascertained from the crankshaft behavior measurement and the crankshaft vibration contribution analysis.
2016-04-05
Technical Paper
2016-01-1617
Yoshinobu Yamade, Chisachi Kato, Shinobu Yoshimura, Akiyoshi Iida, Keiichiro Iida, Kunizo Onda, Yoshimitsu Hashizume, Yang GUO
The objective of this research is to predict accurately aeroacoustical interior noise of a car for a wide range of frequency between 100 Hz and 4 kHz. One-way coupled simulations of CFD, structural analysis and acoustical analysis were performed to predict the interior aeroacoustical noise. Statistical Energy Analysis (SEA), which is a traditional method for evaluating transmission of sound and interior sound field, cannot be used for a low frequency range, while the proposed method can be used for a wide range of frequency including a low frequency range. We predicted pressure fluctuations on the external surfaces of a car by computing unsteady flow around a car as the first step. Secondly, the predicted pressure fluctuations were fed to the subsequent structural analysis to predict vibration accelerations on the internal surfaces of the car.
2016-04-05
Technical Paper
2016-01-1306
Valentin Soloiu, Emerald Simons, Martin Muinos, Spencer Harp, Aliyah Knowles, Gustavo Molina
Diesel engines provide the necessary power for accomplishing heavy tasks across the industries, but are known to produce high levels of noise. Additionally, each type of fuel possesses unique combustion characteristics that lead to different sound and vibration signatures. Noise is an indication of vibration, and components under excessive vibration may wear prematurely, leading to repair costs and downtime. New fuels that are sought to reduce emissions, and promote sustainability and energy independence must be investigated for compatibility from a sound and vibrations point-of-view also. In this research, the sound and vibration levels were analyzed for an omnivorous, single cylinder, CI research engine with alternative fuels and an advanced combustion strategy, RCCI. The fuels used were ULSD#2 as baseline, natural gas derived synthetic kerosene, and a low reactivity fuel n-Butanol for the PFI in the RCCI process.
2016-04-05
Technical Paper
2016-01-1313
Brian Pinkelman, Woo-Keun Song
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 expanded to measure sound quality. The characteristic and the nature of the sound are studied. As an example equal or near equal sound levels can provide different experiences to the listener. Such was 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 we could find no objective measurement of vibration level that could reliable confirm the sensory experience. Yet these particular experiences correlated to certain verbal descriptors including smoothness or roughness.
2016-04-05
Technical Paper
2016-01-1308
Kristian Lee Lardner, Moustafa El-Gindy, Fredrik Oijer, Inge Johansson, David Philipps
The handling and comfort characteristics of a vehicle are greatly impacted by the tire harmonics and these harmonics are known to be affected by several other external and internal parameters. The first mode of vibration is instigated by the tire moving in the vertical direction. This movement is typical of a tire when it drives over obstacles such as pot holes, or speed bumps over a road profile. More importantly, the force that occurs at the first harmonic is transmitted through the tire spindle to the rim, tire axle, and chassis of the vehicle directly affecting the handling and comfortability of the vehicle which is an important factor for trucks and tractor trailers involving heavy and expensive cargo. The purpose of this study is to determine the effect of tire operating conditions, such as the inflation pressure, speed, and load on the change of frequency of the first mode of vibration.
2016-04-05
Technical Paper
2016-01-1114
Jinsung Kim
A dry clutch is vulnerable to 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. The amplitude of vibrations is detected by the signal conditioning from the measurements with the transmission input shaft spend and the wheel speed sensors. Based upon this, a perturbation 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
2016-01-1616
Keiichiro Iida, Kunizo Onda, Akiyoshi Iida, Chisachi Kato, Shinobu Yoshimura, Yoshinobu Yamade, Yoshimitsu Hashizume, Yang GUO
The objective of this research is to predict accurately aeroacoustical interior noise of a car for a wide range of frequency between 100 Hz and 4 kHz. In this study, one-way coupled simulation of computational fluid dynamics (CFD), structural and acoustical analyses were performed to predict flow induced interior noise. Statistical Energy Analysis (SEA), which is a traditional method for evaluating transmission of sound and interior sound field, cannot be used for a low frequency range. In this study, structural and vibrational analysis and acoustical analysis were performed to predict the interior noise. This proposed method can be used for a wide range of frequency between 100 Hz and 4 kHz including a low frequency range. In this paper, the structural and vibrational analyses were performed by using the finite element method (FEM). The acoustical analysis results were compared the wind tunnel experimental results.
2016-04-05
Technical Paper
2016-01-0275
Frédéric Kihm, Andrew Halfpenny, Kurt Munson
Components of ground vehicles are designed to withstand the real operational conditions they will experience during their service life. Vibration tests are performed to qualify their endurance. In order to replicate the same failure mechanism as in real conditions, the test specification must be representative of the service loads. The accelerated testing method, based on fatigue damage spectra (FDS), is a process for deriving a vibration profile that has the same damage potential as the real environment. A synthesized power spectral density (PSD) is derived from the sum of all events’ FDS. So far, the obtained synthesized PSD represents a random stationary Gaussian excitation and is applied over a reduced duration. In real life, however, it is common to experience non-Gaussian excitations such as road irregularities. Random stationary Gaussian test signals do not accurately represent the bursts experienced in service use.
2016-04-05
Technical Paper
2016-01-1325
Masanori Watanabe, Yosuke Tanabe, Naoki Yoneya
Recently, the need to reduce noise generated by machines has been increasing because people are generally becoming more environmentally aware. In order to reduce noise efficiently, noise source localization technology by using microphone arrays is applied to many machines. However, it is difficult to identify noise and excitation sources of vehicle components because the size of noise and excitation source is very small compared to other machines. Therefore, the technical issue of vehicle components is to identify the excitation source finely to reduce noise effectively. Hence, the system which can identify the excitation sources has been developed by combining measurement and analysis. This enables to solve noise and vibration problems at an early stage of development and shorten the development period. Results are as follows, (1) Multi physical quantities and multi channel measurement system has been developed.
2016-04-05
Technical Paper
2016-01-1557
Francesco Castellani, Nicola Bartolini, Lorenzo Scappaticci, Davide Astolfi, Matteo Becchetti
Shock absorber is one of the most relevant sub-systems of the suspension system for a wide range of vehicles. Although a high level of development and tuning has been reached, in order to ensure high safety standards in almost every situation, some dynamic phenomena affecting vehicle handling or NHV can appear. The aim of present work is to improve a mathematical model using experimental data from a prototype of monotube shock absorber developed for research purposes. The model takes into account all the main features affecting the global performance of the device, such as non-linear behaviour and the presence of hysteresis loops. Actually, the most important parameters are analyzed, as flow and orifice coefficients of the valves, coefficients of mechanical compliance of the chambers and oil compressibility, dry and viscous friction coefficients.
2016-04-05
Technical Paper
2016-01-1294
Jonggyu KIM, Pyoung Beom Kim, YoungChan Lee, Sunghee Jung, Byeong-Ug Choi
This paper presents the characteristics of a 3 Cylinder CVT vehicle and a process to improve fuel economy and reduce noise and vibration. To increase the lock-up area of damper clutch for the high fuel economy and to decrease booming and vibration affected by lock-up, chassis systems of a driveline and structure resonance characteristics are studied by experiment and simulation. CVT software calibration parameters are optimized for fuel economy and NVH. With This Study, the lock-up area has been increased by 300RPM and the fuel economy has been improved by approximately 1%, while the NVH characteristic is almost same.
2016-04-05
Technical Paper
2016-01-0473
Muthukumar Arunachalam, Arunkumar S, PraveenKumar Sampath, Abdul Haiyum, Beverly Katz
Current generation passenger vehicles are built with several electronic sensors and modules which are required for functioning of passive safety systems precisely and thus directly related to overall vehicle level performance. Most of these sensors and modules are needed to be mounted on vehicle body at locations like pillar or even directly on panels based on its safety functionality and packaging requirements. The body panel or pillar poses local structural resonances and its dynamic behavior might directly affect the functioning of these sensors and modules. Hence the sufficient inertance performance level at sensor mounting locations is required for the proper functioning of those sensors and modules to meet the vibrational target requirement. Drive point modal frequency response function (FRF) analysis at full vehicle model for the frequency range up to 1000 Hz is performed using finite element method (FEM) and verified against the target level.
2016-04-05
Technical Paper
2016-01-1349
Siddharth Bhupendra Unadkat, Suhas Kangde, Mahalingesh Burkul, Mahesh Badireddy
In current scenario, tremendous amount of thrust is there on CAE to simulate the customer usage pattern or lab test using virtual simulation methods. And is of prime importance to reduce the number of soft tooled or hard tooled prototype for a test if it can be well predicted in CAE. Door slam event in automobiles is one, where structure’s behaviour is complex due to vibration of panels. Current work focuses to derive load histories at different mounting points like hinges, latch and contact patch of door seal area through dynamic analysis using LSDyna. The extracted load histories are then applied to trimmed door Nastran model and Modal transient analysis performed to find the stress history. There is computational advantage with Nastran for performing multiple design iterations compared to LSDyna. Also, stress convergence is achieved with Nastran model. The stresses shown higher in the region where actual failure happened.
2016-04-05
Technical Paper
2016-01-1321
Masahiro Fukazawa, Tsuyoshi Murao, Shingo Unigame
The CAE method to predict the vibration transfer function of the fluid engine mount on a vehicle with sufficient precision and calculation time without prototype cars was developed. The transfer function is given in the following steps.First, rubber deformation form under the power train weight loaded must be predicted. It’s obtained by using a reduction model of engine mount, as a unit, which doesn’t have its fluid sealed inside, with the technique to get static spring characteristics in a non-linear relationship. Second, Young’s modulus and structural damping coefficient for the deformed rubber must be given. As for these characteristics, ignoring the relations between these values and strain, the constant values are used. This considerably reduced computation time and model size.Next, the reduction model and the fluid model which actually the engine mount has must be combined to express actual product.
2016-04-05
Technical Paper
2016-01-1549
Nicola Bartolini, Lorenzo Scappaticci, Francesco Castellani, Alberto Garinei
The knocking noise is a transient structural noise triggered by the shock absorber's piston rod vibrations that excites the vibration of chassis components. Piston rod vibrations can be caused by valves motion (opening and closing) and dry friction during stroke inversions. This study investigates the shock absorber knocking noise on a twintube gas-filled automotive shock absorber and the aim is to define an acceptance criterion (threshold level) for a sample check of the component. If infact the damper derives from a large mass production, may happen that small differences in the assembly might lead to different behaviours resulting in higher or lower levels of knocking noise. To achieve the goal, experimental tests were carried out at various excitation frequencies and amplitudes. Test were performed using a oleodynamic test bench monitoring displacement and force; accelerometers were placed in proximity of the rebound valve, on the body of the damper and on the piston rod.
2016-04-05
Technical Paper
2016-01-1361
Abhijit Londhe, Vivek Yadav, SenthilKumar Kannaiyan, Krishnan Karthikeyan, Ganeshan Reddy
Reducing the vibrations in the drivetrain is one of the prime necessities in today’s automobiles from NVH and strength perspectives. Also to save on material costs and to improve on fuel economy there is a need for optimizing the mass of the engine and vehicle. Platform strategy enables several variants to be designed by changing parameters like Powertrain, wheel base, payload. In those scenarios, changes in stiffness, operating speeds can impact dynamics of drivetrain and of vehicle, this leads to a greater need for addressing the NVH, durability and overall vehicle performance through simulation. Other challenges design engineers have to face are reducing vibrations transferred to vehicle through different load paths such as directly through body mounts and through axle to suspension and then to vehicle cabin. This aggravates other concerns such as shift lever vibrations, rise in in-cab noise, and generation of boom noise at certain speeds.
2016-04-05
Technical Paper
2016-01-0273
Richard DeJong, Se Ge Jung, John Van Baren
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
2016-01-1300
Jacob Milhorn, Vincent Rovedatti, Richard DeJong, Gordon Ebbitt
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 tire and wind noise. Comparisons are also made with wind noise measurements in a scale model wind tunnel test.
Viewing 1 to 30 of 2347

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