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2017-01-15
Book
This is the electronic format of the Journal.
2016-11-08
Technical Paper
2016-32-0041
Chao-Kai LI, Jia-Siou wu, Yuh-Yih Wu
Today, motorcycle is one of the main noise pollution in Asia. In addition, the design of motorcycle muffler is closely related with how noise is made as the regulation is getting crucial these years. Therefore, Transmission Loss (TL) is an important index to evaluate the characteristic of muffler, but conventional trial and error method results in time wasting muffler tests. In this paper, in order to shorten the development period, Ricardo WAVE software is used to discuss the simulate analysis TL of motorcycle muffler. In this paper uses the huge heavy motorbike (400cc) made from manufacture to simulate TL. Due to the complex interior design of the target muffler which is mainly made of simple elements, this research put simulate analysis on simple elements like single chamber, non-coaxial and insert expansion chamber, clapboard chamber and sound absorbing materials at first place. There are three goals in this research.
2016-11-08
Technical Paper
2016-32-0043
Bernhard J. Graf, Christian Hubmann, Markus Resch, Mehdi Mehrgou
Beside hard facts as performance, emissions and fuel consumption especially the brand specific attributes such as styling and sound are very emotional, unique selling prepositions. To develop these emotional characters, within the given boundary conditions of the future pass-by regulation, it is necessary to define them at the very beginning of the project and to follow a consequent development process. The following paper shows examples of motorcycle NVH development work on noise cleaning and sound engineering using a hybrid development process combining front loading, simulation and testing. One of the discussed solutions is the investigation of a piston pin offset in combination with a crankshaft offset for the reduction of friction. The optimization of piston slap noise as a result of the piston secondary motion was performed by simulation. As another example a simulation based development was performed for the exhaust system layout.
2016-11-08
Technical Paper
2016-32-0044
Gaku Naoe
One of the issues involved in compression ignition combustion is the increase in combustion noise from engine mechanical systems caused by rapid combustion. When using natural gas of high ignition temperature in the fuel, the compression ratio is increased relative to gasoline, and combustion becomes more rapid. The present research pursues the issue of noise by clarifying the distinctive features of combustion noise through tests focused on the two topics of stroke bore ratio (S/B ratio), and ignition timing. In order to verify S/B ratio and in-cylinder pressure change rate, combustion noise was measured in five types of engine with the same displacement and the S/B ratio varying from 0.8 to 2.1. The test results seemed that the effect of input load reduction due to the smaller bore caused a reduction in combustion noise at the same in-cylinder pressure change rate.
2016-11-08
Technical Paper
2016-32-0039
Andrea Fioravanti, Giovanni Vichi, Isacco Stiaccini, Giovanni Ferrara, Lorenzo Ferrari
In recent years, the motorcycle muffler design are moving to dissipative silencer architectures. Indeed due to the increase of restrictions on noise emissions both dissipative and coupled reactive-dissipative mufflers, thanks to their higher noise efficiency coupled with a size reduction, have substituted the reactive silencers. A dissipative muffler is composed by a perforated pipe that crosses a cavity volume that is usually filled by a fibrous porous material. The acoustic performance of this kind of muffler are strictly dependent on the porosity of the perforated pipe and the flow resistivity of the porous material. The interaction between these elements and the mass flow rate of gas passing through the silencer influences the muffler performance.
2016-10-17
Technical Paper
2016-01-2311
Arun Prasath G, Saravanan Duraiarasan, Govindarajan R
Indian two wheeler market is one of the largest and highly competitive in the world. Indian scooter segment grows at a pace of around 30% YOY. The stiff competition among OEM’s to increase the market share with fuel efficient and high performance products pushes development and calibration engineers to burn the midnight oil to concoct innovative methods to design technology boosted product. Customer expectations are always high in terms of fuel economy, drivability and NVH. Due to higher level of complexity involved in CVT (Continuously Varying Transmission) engine, it is daunting task to optimize for achieving best of NVH characteristics along with Fuel Economy, drivability and reduced exhaust emission. This paper describes the experiment conducted during the development of 110cc CVT four stroke scooter engine. The development and calibration of this scooter was mainly based on real world usage pattern (RWUP).
2016-10-17
Technical Paper
2016-01-2258
Yoshihiro Okoshi, Shinsuke Kikuchi, Yuta Mitsugi, Kotaro Tanaka, Masaaki Kato, Tomoya Tsuji, Mitsuru Konno
Dimethyl ether (DME) is a promising alternative fuel for CI engines. DME features good auto ignition characteristics and soot-free combustion. In order to develop an injection system suitable for DME, it is necessary to understand the fuel properties. Sound speed is one of the important fuel properties that affects the injection characteristics. However, the measurement data under high-pressure corresponding to that in fuel injection system are lacking. Critical temperature of DME is lower than that of diesel fuel, and is close to the injection condition. Sound speed at critical point is theoretically 0 m/s. It is important to understand the behavior of the sound speed around the critical point. In this study, we measured sound speed in a wide pressure and temperature range of 1-80 MPa, 298-413 K, including the critical point. Sound speed in DME increases with pressure rises or temperature falls. It is approximately 400 m/s slower than that in diesel fuel.
2016-10-17
Technical Paper
2016-01-2343
Mark Devlin, Darryl Williams, Michael Glasgow, Karen Hux, Aaron Whitworth, Timothy Cameron
Improving vehicle fuel efficiency is a key market driver in the automotive industry. Typically lubricant chemists focus on reducing viscosity and friction to reduce parasitic energy losses in order to improve automotive fuel efficiency. However, in a transmission other factors may be more important. If an engine can operate at high torque levels the conversion of chemical energy in the fuel to mechanical energy is dramatically increased. However high torque levels in transmissions may cause NVH to occur. The proper combination of friction material and fluid can be used to address this issue. Friction in clutches is controlled by asperity friction and hydrodynamic friction. Asperity friction can be controlled with friction modifiers in the ATF. Hydrodynamic friction control is more complex because it involves the flow characteristics of friction materials and complex viscosity properties of the fluid.
2016-09-27
Technical Paper
2016-01-8051
Jixiu Zhang, Shuming Chen, Dengfeng Wang
In order to predict the interior noise of a commercial vehicle cab, a finite element model of a heavy commercial vehicle cab was established. An acoustic-structure coupling model of the cab was built based on experimentally validated structure model and acoustic model of a commercial vehicle cab. Moreover, based on the platform of Virtual. Lab, the acoustic field modes of the acoustic model of the commercial vehicle cab and the coupled modes of the acoustic-structure coupling model were analyzed by using the acoustic-structure coupling analysis technique. The excitation of the vehicle cab was tested at an average speed on an asphalt road. Then, the interior noise of the heavy commercial vehicle cab was predicted based on FEM-FEM method and FEM-BEM method with all the parameters and excitation. Furthermore, the predicted interior noise of the commercial vehicle cab was compared with the tested interior noise.
2016-09-27
Technical Paper
2016-01-8101
Yoshimune Mori, Akifumi Yoshimura, Nobutaka Tsujiuchi, Akihito Ito, Atsushi Fujimoto, Zenzo Yamaguchi, Koichi Honke
In a typical mechanical product such as automobile and construction machinery, it is a general method that identify the deformation mode in which significant improvement target of contributing to the response from the experiments and analysis solution and consider the structure of the proposed improvements in the way of high rigidity by using a technique such as strain energy method in the conventional design and development. In however the above-mentioned method, it is often a conflicting results with weight saving and cost reduction that were required from development. Transfer path analysis (TPA) using FEM is an effective method of reducing noise and vibration of the automobile with respect to these issues. TPA can reveal that the transfer path from the input to the response of the evaluation point and the contribution of the path and consider the improvement of the response efficiently.
2016-09-27
Technical Paper
2016-01-8143
Jerry Syms, Theresia Manns, Björn Bergqvist
The noise generated by the flow of air past a transport truck is a key design factor for the manufacturers of these vehicles as the sound levels in the cabin are a significant component of driver comfort. This paper describes a demonstration study to measure the in-cabin aeroacoustic environment of a full-scale cab-over tractor in the NRC 9 m Wind Tunnel. Acoustic instrumentation was installed inside the tractor to record cabin noise levels and externally to acquire tunnel background noise data. Using a microphone mounted on the driver’s-side tunnel wall as a reference to remove variations in background noise levels between data points, differences in cabin noise levels were able to be detected when comparing the tractor with different configurations. The good repeatability of the data allowed for differences of as little as 0.5dB to be measured.
2016-09-20
Technical Paper
2016-01-2009
Natasha Barbely, Narayanan Komerath, Nandeesh Hiremath
Abstract Coaxial rotors are finding use in advanced rotorcraft concepts. Combined with lift offset rotor technology, they offer a solution to the problems of dynamic stall and reverse flow that often limit single rotor forward flight speeds. In addition, coaxial rotorcraft systems do not need a tail rotor, a major boon during operation in confined areas. However, the operation of two counter-rotating rotors in close proximity generates many possible aerodynamic interactions between rotor blades, blades and vortices, and between vortices. With two rotors, the parameter design space is very large, and requires efficient computations as well as basic experiments to explore aerodynamics of a coaxial rotor and the effects on performance, loads, and acoustics.
2016-09-18
Technical Paper
2016-01-1918
Yusuke Aoki, Yasuyuki Kanehira, Yukio Nishizawa
Brake squeal is an uncomfortable noise that occurs while braking. So, it is an important issue for automobile quality to prevent brake products from squealing. Brake shims are widely used to reduce squeal occurrence rate. To quantify the anti-squeal effect of shims, loss factor has been measured with a bending mode tester, instead of repeating many dynamometer tests. However, there are cases where measurement results have less correlation to actual squeal suppression rate. Therefore, we have to evaluate the anti-squeal effect by dynamometer or on an actual car until the best shim can be selected. In this work, we focused on the differences between measurement conditions and actual braking conditions of shims to obtain a good correlation. The bending mode tester measures loss factor under pressure-free condition even though shims are compressed by pistons or cylinders towards the backplate of the pad.
2016-09-18
Technical Paper
2016-01-1921
Yusuke Sunagawa, Tsuyoshi Kondo
Brake squeal noise is generally classified into two vibration modes of disc. One is called “out-of plane mode” which vibrates in disc’s out-of-plane direction. The other is “In-plane mode” which vibrates in disc’s in-plane direction, it means the disc is contracted partially or is extended. There are few “In-plane noise” analysis reports from Disc pad standpoint, so it has been unclear how disc pad contributes to “In-plane mode” until now. This paper confirms that we successfully analyzed direct pad vibration mode by laser scanning under in-plane mode condition. Based on these results, we assume that pad stiffness affected in-plane mode and carried out validation tests.
2016-09-18
Technical Paper
2016-01-1922
Yongchang Du, Yujian Wang
Modelling of disc is crucial in analyzing brake squeal since the disc rotates past the non-rotating pads and the pads are coupled with different areas of the disc at different times. However, in most of the complex eigenvalue analysis of brake squeal, the effect of disc rotation was ignored. This paper proposes a closed-loop coupling model for brake squeal analysis. A modal parameter–based rotating disc model, whose dynamic behavior is represented by rotation speed-dependent equivalent modal parameters, is built through space and time-frequency transformation between reference and moving systems. The orthogonality of the equivalent modal parameters in state-space is derived. By performing modal synthesis in state-space, the rotating disc is incorporated into brake squeal closed-loop coupling model with other stationary components. Dynamic instability of the system is solved through complex eigenvalue analysis in state-space.
2016-09-18
Technical Paper
2016-01-1915
Meechai Sriwiboon, Seong Rhee, Kritsana Kaewlob, Nipon Tiempan, Rungrod Samankitesakul
Two formulations have been selected and tested for this investigation; Low-Copper NAO and Copper – Free NAO. Each formulation was processed to achieve 3 levels of porosity; 12, 17 and 22%. Each sample was tested for hardness (HRR, HRS, and HRL), natural frequencies and compressibility plus performance testing for friction, wear and brake squeal. This paper describes correlations or lack of them between all the measurements.
2016-09-18
Journal Article
2016-01-1944
Seongjoo Lee, JeSung Jeon, ShinWook Kim, ShinWan Kim, Seong Rhee, Wan Gyu Lee, Young Sun Cho, Jeongkyu Kim
When two identical brakes are simultaneously tested on a vehicle chassis dynamometer, very often the left hand brake is found to squeal more or less than the right hand brake, all at different frequencies. This study was performed to develop some understanding of this puzzling phenomenon. It is found that as the wear rate difference between the inner pad and the outer pad increases, low frequency (caliper and knuckle) squeals occur more and more, and as the differential wear becomes larger and larger, high frequency (disc) squeals occur less and less, finally disappearing all together. Discs and calipers are found to affect the differential pad wear, in turn affecting brake squeal generation.
2016-09-18
Journal Article
2016-01-1919
Joo Sang Park, Min Gyu Han, Seon Yeol Oh
Abstract This paper introduces the experimental test results of an investigation to understand the relationship between the leading offset and squeal propensity. In addition Transient Analysis (TA) and Complex Eigenvalue Analysis (CEA) are used simultaneously as a means to compare the experimental approach to two different numerical tools, so evaluating the validity of each theoretical approach. To confirm the CAE results. An ODS was recorded of the brake using a 3D laser scanning vibrometer. Even though the CEA approach is very popular in the study of brake squeal noise, there are some limitations and difficulties in replicating the real phenomenon especially containing unstable behavior. The differences are due to weak pad contact stiffness and friction characteristics which are dependent on the relative interface velocity between pad and rotor. It is necessary to consider stick-slip vibration and time domain analysis in addition.
2016-08-11
Standard
AIR1826A
This Aerospace Information Report (AIR) is limited in scope to the general consideration of environmental control system noise and its effect on occupant comfort. Additional information on the control of environmental control system noise may be found in 2.3 and in the documents referenced throughout the text. This document does not contain sufficient direction and detail to accomplish effective and complete acoustic designs.
2016-08-02
Standard
J1324_201608
This SAE Recommended Practice provides test methods for determining the characteristics of acoustical and thermal materials. Where applicable, methods of test developed by SAE and ASTM have been referenced.
2016-07-27
WIP Standard
J1455
The scope of this recommended practice encompasses the range of environments which influence the performance and reliability of the electronic equipment designed for heavy duty on and off road vehicles, as well as any appropriate stationary applications which also use these vehicle derived components. A few examples of such vehicles are on and off highway trucks, trailers, buses, construction equipment and agricultural equipment including implements.
2016-07-12
Standard
AMS3807C
This specification covers aluminum foil tape with a pressure sensitive adhesive.
2016-06-15
Technical Paper
2016-01-1823
Andrea Grosso, Martin Lohrmann
Abstract Operational Transfer Path Analysis (OTPA) assess the possible ways of energy to transfer from the various sources of excitation to a given target location. Applied to vehicle engineering, the OTPA provides indication about dominant sources and path contributions. However, it can only analyze the actual system under test and cannot predict if an improvement can be achieved by applying a counter measure. A careful interpretation of the measurement results is therefore necessary in order to define an effective engineering solution strategy. In this paper the RMA (Response Modification Analysis) technique is used to facilitate a sensitivity analysis, gaining insight whether energy is likely to be rerouted. This gives additional understanding of OTPA results, indicating which counter measure is most effective. The RMA is applied to a real measurement scenario, showing the advantage of the combination of OTPA with RMA for correctly identifying the relevant sources and paths.
2016-06-15
Technical Paper
2016-01-1805
Florian Zenger, Clemens Junger, Manfred Kaltenbacher, Stefan Becker
Abstract A low pressure axial fan for benchmarking numerical methods in the field of aerodynamics and aeroacoustics is presented. The generic fan for this benchmark is a typical fan to be used in commercial applications. The design procedure was according to the blade element theory for low solidity fans. A wide range of experimental data is available, including aerodynamic performance of the fan (fan characteristic curve), fluid mechanical quantities on the pressure and suction side from laser Doppler anemometer (LDA) measurements, wall pressure fluctuations in the gap region and sound characteristics on the suction side from sound power and microphone array measurements. The experimental setups are described in detail, as to ease reproducibility of measurement positions. This offers the opportunity of validating aerodynamic and aeroacoustic quantities, obtained from different numerical tools and procedures.
2016-06-15
Technical Paper
2016-01-1806
Sumon Sinha, Farokh Kavarana, Dan Williams, Kazuya Asao
Abstract A high performance rigid airfoil profile sunroof wind deflector has been developed for high speed freeway driving with the sunroof open. This deflector is clearly superior to the conventional bar type deflector and less expensive compared to tall flexible fabric mesh deflectors applied on high end vehicles today. It provides superior speech intelligibility under high speed driving with sunroof open. The criterion for designing this deflector was to get the highest airspeed possible to span the sunroof opening under all conditions. The customized shape also utilizes flow unsteadiness, including those at the onset of buffeting, in order to condition the shear layer. The airfoil profiled deflector yielded superior mid and high frequency acoustic performance with acceptable low frequency performance. A shorter airfoil deflector was sufficient to keep the external airflow from entering the forward tilted sunroof opening on a mid-size SUV under test.
2016-06-15
Technical Paper
2016-01-1803
Hannes Frank, Claus-Dieter Munz
Avoiding narrowband components in the acoustic spectrum is one of the most critical objectives in the automotive aeroacoustic optimization process. The underlying physical mechanisms are not completely understood. In a preceding numerical and experimental investigation, we performed large eddy simulations of an early-development stage realistic side-view mirror, where tonal noise was captured and the principle mechanisms were identified. In this contribution, we present simulations on a simplified two-dimensional geometry that is based on these findings. It is shown that the basic flow topology relevant for tonal noise generation on the original side-view mirror as well as the tonal noise source is reproduced in the 2D case. Furthermore, we present comparisons with measurements and the necessity and influence of a splitter plate downstream of the 2D body to avoid large scale vortex shedding.
2016-06-15
Technical Paper
2016-01-1802
Mehdi Mehrgou, Franz Zieher, Christoph Priestner
Abstract Recently, hybrid and fully electric drives have been developing widely in variety, power and range. The new reliable simulation approaches are needed, in order to meet the defined NVH targets of these systems and implementing CAE methods for front loading, Design Validation Process (DVP). This paper introduces the application of a novel NVH analysis workflow on an electric vehicle driveline including both electromagnetic and mechanical excitations for an absolute evaluation of the NVH performance. At first, the electromagnetic field is simulated using FEM method to extract the excitations on the stator, rotor bearings as well as the drive torque. Then, the multibody dynamic model of the driveline is built-up, driven by this torque. The effect of eccentricity and skew angle of rotor in electromagnetic excitations are shown.
2016-06-15
Technical Paper
2016-01-1796
Aurélien Cloix, Jean-Luc Wojtowicki
Abstract The current paper is based on the French research program TESSA (“Transfert des Efforts des Sources Solidiennes Actives”). A specific task within TESSA project consists in the characterization of the measurements variability between several laboratories, of the blocked forces on a water pump of a heat engine. This paper focuses only on the measurements carried out at Vibratec laboratory. Two kinds of measurements have been carried out: direct measurements, using force sensors, which is the target of the inter-laboratory measurements, and an inverse method without force sensor requirements. Reproducibility and repeatability tests have been done in order to quantify the measurement variability within the same laboratory, in preparation for the inter-laboratory disparity analysis.
2016-06-15
Technical Paper
2016-01-1798
Quentin Buisson, Jean-Louis Guyader, Serge Puvilland, Xavier Carniel, Maximilien Soenen
Abstract The goal of the present study is to provide a simple method to compare structure borne noise sources in order to choose the most efficient one, considering the transmission of dynamic forces. It is well known that mechanical sources are not only dependent of the source itself but also of the receiving structure, in addition real sources cannot be reduced to a transverse force acting on the structure but more complicated effect like moment excitation must be taken into account. The advantage of the reception plate method is to characterize the source globally by the level of vibration of the reception plate whatever the type of excitation, the idea is basically to characterize mechanical sources as it is done for acoustical sources in reverberant rooms. A reception plate test bench has been developed to determine the power injected by mechanical sources. Two prototype plates have been designed in order to have different receiving mobilities.
2016-06-15
Technical Paper
2016-01-1794
Jonathan Caprile, Claire Chaufour, Pierre Emile Chartrain
Abstract In automotive NVH, the noise generated by a powertrain is still one of the major noise sources especially at low and mid vehicle velocity. For this reason automotive OEMs are continuously focusing on methods to efficiently analyze this noise source. For this purpose, a well-established simulation methodology can provide results thoroughly, within a limited amount of time and with a reduced cost contrary to experiments which are involved in late design phases and are more expensive. This paper aims at presenting an approach to simulate efficiently the acoustic radiation from automotive components. With this aim in mind, the acoustic response of a realistic powertrain unit subjected to working conditions ranging from 1000 RPM to 4500 RPM is studied until 3000 Hz. Several radiating boundary conditions will be assessed in order to detect the most efficient set-up for this kind of problem and to extract the optimized modeling guidelines.
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