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2017-10-08
Technical Paper
2017-01-2428
Peilin Dai, Ying Huang, Donghao Hao, Ting Zhang
Abstract: The vehicle driveline suffers low frequency torsional vibration because of the abrupt change of torque and torque fluctuation of variable frequency. This problem can be solved by model-based predictive control, so building a control oriented driveline model is extremely important. The traditional off-line identified model which does not consider driveline parameter variation such as damping of tire and suspension during vehicle operation cannot accurately reflect the true characteristics of the driveline vibrations. And usually the fixed stiffness is considered, this will cause modeling errors and worse result of vibration control, in this paper, an on-line recursive identification method is proposed and verified based on an electric car. First of all, as for the low frequency vibration, the control oriented model is simplified into a six-parameter model with double inertia.
2017-09-19
Technical Paper
2017-01-2137
Dnyaneshwar V. Kadam, Sangram D. Jadhav
Vibration is the most considerable factor in dynamics of machinery. Vibration causes unfavorable effects on engine components and may reduce the life of engine. The conventional fossil fuel sources are limited in the world. The dependency on diesel should be reduced by using biodiesel as an alternative fuel in next few years. The input parameters are affected on engine performance and emission. The present study mainly focuses on an optimization of vibrations, performance and emission using Taguchi and multiple regression analysis for biodiesel as a fuel. The test was performed on single cylinder, four-stroke, diesel engine with VCR. Taguchi method is used to prepare the design of experiment of L16 array for minimizing number of experiments and multiple regression analysis for finding the best relationship between the input and output parameters. The selected input parameters are: fuel fraction, compression ratio, injection pressure and injection timing.
2017-09-17
Technical Paper
2017-01-2488
Manuel Pürscher, Peter Fischer
Vehicle road tests are meaningful for investigations of creep groan noise. However, problems in reproducing experiments and partly subjective evaluations may lead to imprecise conclusions. This work proposes an experimental test and evaluation procedure which provides a precise and objective assessment of creep groan. It is based on systematic corner test rig experiments and an innovative characterization method. The exemplary setup under investigation consisted of a complete front wheel suspension and brake system including all relevant components. The wheel has been driven by the test rig’s drum against a brake torque. The main parameters within a test matrix were brake pressure and drum velocity. Both have been varied stepwise to scan the relevant operating range of the automobile corner system for potential creep groan noise. Additionally, the experiments were extended to high brake pressures, where creep groan cannot be observed under road test conditions.
2017-07-10
Technical Paper
2017-28-1926
Jos Frank, Sohin Doshi, Manchi Rao, Prasath Raghavendran
Abstract In today’s automotive scenario, noise vibration and harshness (NVH) has become a synonym for quality perception. This paper evaluates the problem of vibration and noise experienced in M2 category 40 seat bus and suggests the counter measures. Severe vibration is experienced on the bus floor, predominantly towards rear part of the bus. Vibration along with acoustic boom occurs prominently in 4th gear wide open throttle operating condition between 1300-1600 rpm of the engine. This paper focuses on reducing NVH levels by working on the transfer path with little modifications on power-train. Preliminary torsional measurements conducted on powertrain indicated high torsional excitation in the driveline during the problematic rpm zone. Further, Operational Deflection Shape (ODS) analysis revealed that the transfer path to the cabin is rear differential unit and suspension links. The dominant frequencies were identified along the transfer path and suitable modifications were done.
2017-07-10
Technical Paper
2017-28-1925
Asif Basha Shaik Mohammad, Ravindran Vijayakumar, Nageshwar Rao Panduranga
Abstract The automotive market has seen a steady increase in customer demands for quiet and more comfortable tractors. High noise at Operator Ear Level (OEL) of tractor is the major cause of fatigue to the operator. With growing competition, and upcoming legislative requirement there is ominous need for the agricultural tractor manufacturers to control noise levels. The objective of this study is noise reduction on agricultural tractor by stiffening sheet metal components. The design and analysis plays a major role for determining the root cause for the problem. Once the problem and its root cause were well defined, the solution for addressing the problem would be made clear. The engine excitation frequency and Sheet metal Components such as fender and platform natural frequency were coming closer and are leading to resonance.
2017-07-10
Technical Paper
2017-28-1928
Rajesh Babu Channamaneni, P Kannan, Prasad Padavala
Abstract Engine mounts and mounting brackets play a critical role in determining NVH performance of a vehicle. A lot of work has been done in the area of virtual simulation using FE models to study engine mounting system performance and its impact on vehicle level performance. An overall approach towards engine mounting system validation at vehicle level is also very critical to validate simulation results in a prototype based on which further refinement work will be carried. In this paper a detailed procedure for engine mount and mounting bracket physical validation at vehicle level is presented. Various tests to be performed at vehicle level to quantify engine mount and mounting bracket performance parameters is discussed in detail along with measurement procedures and techniques. Test results are interpreted and its impact on overall performance is also explained.
2017-07-10
Technical Paper
2017-28-1969
Senthil Ram Nagapillai Durairaj, Thulasirajan Ganesan, Praveen Chakrapani Rao
Abstract Magnesium alloy current being used for automotive sector and are being significantly used for manufacturing engine block as offering higher power to weight ratio to the vehicle. In this context, the magnesium alloy has been used in the replacement of aluminium alloy for the starter housing which in turn increase the power to weight ratio of the motor. Considering the operation condition of starter motor in the engine of the vehicles, the starter motor is being exposed to the harsh environment, where its system is being tested for Noise, Vibration and Harshness. In this paper, the magnesium alloy housing is used to study the vibration and noise developed in the starter motor and the same is compared with the noise and vibration of the motor when it being used with Aluminium alloy Housing. First, the vibration study is carried out for the housing part alone to capture the resonant frequency of the both housing alloy say, Aluminium and Magnesium.
2017-06-05
Technical Paper
2017-01-1785
Paul Bremner, Scott Clifton, Chris Todter
Abstract Measurements of interior wind noise sound pressure level have shown that dBA and Loudness are not adequate metrics of wind noise sound quality due to non-stationary characteristics such as temporal modulation and impulse. A surface microphone array with high spatio-temporal resolution has been used to measure and analyze the corresponding non-stationary characteristics of the exterior aero-acoustic loading. Wavenumber filtering is used to observe the unsteady character of the low wavenumber aero-acoustic loading components most likely to be exciting glass vibration and transmitting sound.
2017-06-05
Technical Paper
2017-01-1799
Nagasuresh Inavolu, Jaganmohan Rao Medisetti, S. Nanda Kumar, J Lingeshkumar, Akshay Loya, Mvgprasad MV
Abstract Engine noise reduction is one of the highest priorities in vehicle development from the viewpoint of meeting stringent noise regulations. Engine noise reduction involves identification of noise sources and suppression of noise by changing the response of sources to input excitations. Noise can originate from several mechanical sources in engine. The present work focuses on systematic study of the behavior or response of engine structure and its ancillaries to engine excitation and thereby assess their contribution to overall engine noise. The approach includes engine noise and vibration measurement and component ranking using engine noise and vibration measurement in a non-anechoic environment, structural analysis of engine including experimental modal testing of engine and its components, etc. Correlation of the above obtained results is performed to identify the noise sources. Later, ranking of critical components was performed based on results of cladding exercise.
2017-06-05
Technical Paper
2017-01-1803
John Van Baren
Abstract The accumulated damage that a product experiences in the field due to the variety of vibration stresses placed upon it will eventually cause failures in the product. The failure modes resulting from these dynamic stresses can be replicated in the laboratory and correlated to end use environment to validate target reliability requirements. This presentation addresses three fundamental questions about developing accelerated random vibration stress tests.
2017-06-05
Technical Paper
2017-01-1801
Sivasankaran Sadasivam, Aditya Palsule, Ekambaram Loganathan, Nagasuresh Inavolu, Jaganmohan Rao Medisetti
Abstract Powertrain is the major source of noise and vibration in commercial vehicles and has significant contribution on both interior and exterior noise levels. It is vital to reduce the radiated noise from powertrain to meet customer expectations of vehicle comfort and to abide by the legislative noise requirements. Sound intensity mapping technique can identify the critical components of noise radiation from the powertrain. Sound intensity mapping has revealed that oil sump as one of the major contributors for radiated noise from powertrain. Accounting the effect of dynamic coupling of oil on the sump is crucial in predicting its noise radiation performance. Through numerical methods, some amount of work done in predicting the dynamic characteristics of structures filled with fluid.
2017-06-05
Technical Paper
2017-01-1807
Richard DeJong, Gordon Ebbitt
Abstract The SEA model of wind noise requires the quantification of both the acoustic as well as the turbulent flow contributions to the exterior pressure. The acoustic pressure is difficult to measure because it is usually much lower in amplitude than the turbulent pressure. However, the coupling of the acoustic pressure to the surface vibration is usually much stronger than the turbulent pressure, especially in the acoustic coincidence frequency range. The coupling is determined by the spatial matching between the pressure and the vibration which can be described by the wavenumber spectra. This paper uses measured vibration modes of a vehicle window to determine the coupling to both acoustic and turbulent pressure fields and compares these to the results from an SEA model. The interior acoustic intensity radiating from the window during road tests is also used to validate the results.
2017-06-05
Technical Paper
2017-01-1804
Chulwoo Jung, Hyeon Seok Kim, Hyuckjin Oh, Kwang Hyeon Hwang, Hun Park
Abstract An efficient method to determine optimal bushing stiffness for improving noise and vibration of passenger cars is developed. In general, a passenger vehicle includes various bushings to connect body and chassis systems. These bushings control forces transferred between the systems. Noise and vibration of a vehicle are mainly caused by the forces from powertrain (engine and transmission) and road excitation. If bushings transfer less force to the body, levels of noise and vibration will be decreased. In order to manage the forces, bushing stiffness plays an important role. Therefore, it is required to properly design bushing stiffness when developing passenger vehicles. In the development process of a vehicle, bushing stiffness is decided in the early stage (before the test of an actual vehicle) and it is not validated until the test is performed.
2017-06-05
Technical Paper
2017-01-1805
Krzysztof Prażnowski, Jaroslaw Mamala
Abstract The vibrations of the sprung mass of a passenger car, traveling along a road surface, are random. They also form its main source but there are besides other factors to consider. The resulting force ratio is overlapped by other phenomena occurring at the interface of the pneumatic tire with the road surface, such as non-uniformity of tires, shape deformations and imbalances. The resulting additional inertia force acts on the kinematic force that was previously induced on the car body. The vibrations of the sprung mass of the car body at the time can be considered as a potential source of diagnostic information, but getting insight their direct identification is difficult. Moreover, the basic identification is complicated because of the forces induced due to the random interference from road roughness. In such a case, the ratio defined as SNR assumes negative values.
2017-06-05
Technical Paper
2017-01-1808
Francis Nardella
Abstract In a previous report, it was shown that power transmission through the camshaft reduced the first mode natural frequency of the power train and translated its convergence with dominant engine excitatory harmonics to a lower engine speed resulting in a marked reduction in torsional vibration while achieving 2/1 gear reduction for a 4-stroke 6-cylinder compression ignition (CI) engine for aviation. This report describes a sweep though 2 and 4-stroke engines with differing numbers of cylinders configured as standard gear reduction (SGRE) and with power transmission through the camshaft (CDSE) or an equivalent dedicated internal driveshaft (DISE). Four and 6-cylinder 4-stroke engines were modeled as opposed boxer engines. Four and 6-cylinder 2-stroke engines and 8, 10 and 12-cylinder 2-stroke and 4-stroke engines were modeled as 180° V-engines. All 2-stroke engines were considered to be piston ported and configured as SGRE or DISE.
2017-06-05
Technical Paper
2017-01-1761
Daniel Fernandez Comesana, Graciano Carrillo Pousa, Emiel Tijs
Abstract The automotive industry is currently increasing the noise and vibration requirements of vehicle components. A detailed vibro-acoustic assessment of the supplied element is commonly enforced by most vehicle manufacturers. Traditional End-Of-Line (EOL) solutions often encounter difficulties adapting from controlled environments to industrial production lines due the presence of high levels of noise and vibrations generated by the surrounding machinery. In contrast, particle velocity measurements performed near a rigid radiating surface are less affected by background noise and they can potentially be used to address noise problems even in such conditions. The vector nature of particle velocity, an intrinsic dependency upon surface displacement and sensor directivity are the main advantages over conventional solutions. As a result, quantitative measurements describing the vibro-acoustic behavior of a device can be performed at the final stage of the manufacturing process.
2017-06-05
Technical Paper
2017-01-1766
Dirk von Werne, Stefano Orlando, Anneleen Van Gils, Thierry Olbrechts, Ivan Bosmans
Abstract A methodology to secure cabin noise and vibration targets is presented. Early in the design process, typically in the Joint Definition Phase, Targets are cascaded from system to component level to comply with the overall cabin noise target in various load cases. During the Detailed Design Phase, 3D simulation models are build up to further secure and refine the vibro-acoustic performance of the cabin noise related subsystems. Noise sources are estimated for the target setting based on layer analytical and empirical expressions from literature. This includes various types of engine noise - fan, jet, and propeller noise - as well as turbulent boundary layer noise. For other noise sources, ECS and various auxiliaries, targets are set such as to ensure the overall cabin noise level. To synthesize the cabin noise, these noise sources are combined with estimates of the noise transfer through panels and the cavity effect of the cabin.
2017-06-05
Technical Paper
2017-01-1768
Yong Xu
Abstract The NVH performance is one of the most important concerns in vehicle development. For all-wheel drive (AWD) vehicles and rear-wheel (RWD) drive vehicles, prop shaft is a major transmission component which may cause various NVH problems. This paper focuses on the vehicle NVH problems caused by the second order excitation force of prop shaft. In order to control the NVH performance of the prop shaft efficiently and fundamentally, this work first studied the rotation kinematical characteristics of prop shaft. Then a rigid-elastic coupling model of vehicle driveline was built with the theory of multi-body dynamics. With this model, the sensitive factors that may affect the second order excitation force were investigated. This paper also describes a case study to verify the conclusions which are revealed from the theoretical calculation and the simulation.
2017-06-05
Technical Paper
2017-01-1773
Jing Yuan
Abstract The dual phase twin synchronous drive has been developed for belt noise reduction. Two identical synchronous belts are arranged parallel side by side with one tooth staggered against other by the half pitch offset. The noise cancellation effect is achieved as one belt tooth engagement coincides with the other belt tooth dis-engagement. A center flange is used as a divider to prevent the belts contacting each other along the axial direction during their entrance and exit of the sprocket. An overall 20 [dBA] noise reduction has been achieved with the dual phase twin belt drive compared to an equal width single belt counterpart. The vibration amplitude of the hub load is also reduced which is directly correlated to the structural borne noise. Comparing to the related dual phase helical tooth belt, the dual phase twin belt is superior in torque carrying capability; and is on par with noise mitigation.
2017-06-05
Technical Paper
2017-01-1778
Enrico Galvagno, Antonio Tota, Mauro Velardocchia, Alessandro Vigliani
Abstract This paper explores the potentiality of reducing noise and vibration of a vehicle transmission thanks to powertrain control integration with active braking. Due to external disturbances, coming from the driver, e.g. during tip-in / tip-out maneuvers, or from the road, e.g. crossing a speed bump or driving on a rough road, the torsional backlashes between transmission rotating components (gears, synchronizers, splines, CV joints), may lead to NVH issues known as clonk. This study initially focuses on the positive effect on transmission NVH performance of a concurrent application of a braking torque at the driving wheels and of an engine torque increase during these maneuvers; then a powertrain/brake integrated control strategy is proposed. The braking system is activated in advance with respect to the perturbation and it is deactivated immediately after to minimize losses.
2017-06-05
Technical Paper
2017-01-1780
Yong Xu
Abstract In the design or match process of vehicle powertrain system, gearbox rattle is a common NVH problem which directly affects passengers’ judgment on the quality and performance of vehicle. During the development process of a passenger car, prototype vehicles have serious gear rattle problem. In order to efficiently and fundamentally control this problem, this work first studied the characteristics and mechanisms of the gearbox rattle. The study results revealed that the torsional vibration of powertrain system was the root cause of gearbox rattle. Then a simulation model of the full vehicle was built with the aid of Simulink® toolbox, which is a graphical extension to MATLAB® for modeling and simulation of variety of systems. With this model, the sensitivity analysis and parametrical optimization were performed, and the simulation results indicated that the dual-mass flywheel (DMF) was the best measure to control the rattle.
2017-06-05
Technical Paper
2017-01-1903
Masami Matsubara, Nobutaka Tsujiuchi, Tomohiko Ise, Shozo Kawamura
Abstract The tire is one of the most important parts, which influence the noise, vibration, and harshness of the passenger cars. It is well known that effect of rotation influences tire vibration characteristics, and earlier studies presented formulas of tire vibration behavior. However, there are no studies of tire vibration including lateral vibration on effect of rotation. In this paper, we present new formulas of tire vibration on effect of rotation using a three-dimensional flexible ring model. The model consists of the cylindrical ring represents the tread and the springs represent the sidewall stiffness. The equation of motion of lateral, longitudinal, and radial vibration on the tread are derived based on the assumption of inextensional deformation. Many of the associated numerical parameters are identified from experimental tests.
2017-06-05
Technical Paper
2017-01-1891
Todd Freeman, Kelby Weilnau
Abstract Similar to the automotive industry, the expectations from customers for the noise and vibration performance of personal vehicles such as golf carts, ATV’s, and side-by-side vehicles has continued to evolve. Not only do customers expect these types of vehicles to be more refined and to have acoustic signatures that match the overall performance capabilities of the vehicle, but marketing efforts continue to focus on product differentiators which can include the acoustic and vibration performance. Due to this increased demand for acoustic and vibration performance, additional NVH efforts are often required to meet these expectations. This paper provides a sample of some of the efforts that have occurred to further refine and develop the noise and vibration signature for golf carts.
2017-06-05
Technical Paper
2017-01-1892
Yosuke Tanabe, Masanori Watanabe, Takafumi Hara, Katsuhiro Hoshino, Akira Inoue, Masaru Yamasaki
Abstract Predicting the vibration of a motor gearbox assembly driven by a PWM inverter in the early stages of development is demanding because the assembly is one of the dominant noise sources of electric vehicles (EVs). In this paper, we propose a simulation model that can predict the transient vibration excited by gear meshing, reaction force from the mount, and electromagnetic forces including the carrier frequency component of the inverter up to 10 kHz. By utilizing the techniques of structural model reduction and state space modeling, the proposed model can predict the vibration of assembly in the operating condition with a system level EV simulator. A verification test was conducted to compare the simulation results with the running test results of the EV.
2017-06-05
Technical Paper
2017-01-1905
Kiran Patil, Javad Baqersad, Jennifer Bastiaan
Abstract Tires are one of the major sources of noise and vibration in vehicles. The vibration characteristic of a tire depends on its resonant frequencies and mode shapes. Hence, it is desirable to study how different parameters affect the characteristics of tires. In the current paper, experimental modal tests are performed on a tire in free-free and fixed conditions. To obtain the mode shapes and the natural frequencies, the tire is excited using a mechanical shaker and the response of the tire to the excitation is measured using three roving tri-axial accelerometers. The mode shapes and resonant frequencies of the tire are extracted using LMS PolyMax modal analysis. The obtained mode shapes in the two configurations are compared using Modal Assurance Criterion (MAC) to show how mode shapes of tires change when the tire is moved from a free-free configuration to a fixed configuration. It is shown that some modes of the tire are more sensitive to boundary conditions.
2017-06-05
Technical Paper
2017-01-1866
Pradeep Jawale, Nagesh Karanth
Abstract Urbanisation has led to an increased need for mobility in public transportation. Sensing the unfolding worrisome scenario, many countries have taken up different mass rapid transit solutions to alleviate the problem and restore the free flowing traffic. BRT should have been the logical choice particularly considering the lower capital costs involved and faster implementation. Comprehensibly the expectations of this class of vehicles will be high in term of quality and comfort to the passengers. Level of vibration and noise is an important indicator to evaluate vehicle's ride comfort. The challenges are to design the high powered Powertrain and Air Conditioning system nonetheless low interior noise, vibration and harshness correspondents to personal cars. This paper is an invention of, development work done in interior noise refinement of a bus. A prototype bus manufactured to meet all the requirement of BRT - premium segment urban bus.
2017-06-05
Technical Paper
2017-01-1865
Peter Van der Linden, Frank Daenen, Masashi Komada, Hideto Ogawa
Abstract The tendency for car engines to reduce the cylinder number and increase the specific torque at low rpm has led to significantly higher levels of low frequency pulsation from the exhaust tailpipe. This is a challenge for exhaust system design, and equally for body design and vehicle integration. The low frequency panel noise contributions were identified using pressure transmissibility and operational sound pressure on the exterior. For this the body was divided into patches. For all patches the pressure transmissibility across the body panels into the interior was measured as well as the sound field over the entire surface of the vehicle body. The panel contributions, the pressure distribution and transmissibility distribution information were combined with acoustic modal analysis in the cabin, providing a better understanding of the airborne transfer.
2017-06-05
Technical Paper
2017-01-1859
Filip Franek, Jungu Kang, Jeon Uk, Sunguk Choi
Abstract Structure-born vibrations are often required to be localized in a complex structure, but in such dispersive medium, the vibration wave propagates with speed dependent on frequency. This property of solid materials causes an adverse effect for localization of vibrational events. The cause behind such phenomenon is that the propagating wave envelope changes its phase delay and amplitude in time and space as it travels in dispersive medium. This problem was previously approached by filtering a signal to focus on frequencies of the wave propagating with a similar speed, with improved accuracy of cross-correlation results. However, application of this technique has not been researched for localization of vibrational sources. In this work we take advantage of filtering prior to cross-correlation calculation while using multiple sensors to indicate an approximate location of vibration sources.
2017-06-05
Technical Paper
2017-01-1855
Ramakanta Routaray
Abstract The basic function of a motorcycle frame is somewhat similar to that of the skeleton in the human body, i.e. to hold together the different parts in one rigid structure. One of the major benefits (for a motorcycle enthusiast) of using an advanced frame design lies in the sporty handling characteristics of the bike. A well designed frame can add to the joy of riding a motorcycle as the bike would feel more stable, effortless, and confident around corners, in straight lines and while braking. A well approved modeling [2] techniques or adequate guide line principles have to be followed while designing the body and chassis in order to achieve the vibration within control. This paper depicts a methodological right approach (guide lines) while designing the body and chassis of a two wheeler in order to control noise and vibration of the body and chassis.
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