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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
2016-32-0042
Bhaarath Rajagopal Jeyapaal, Vamsi Krishna, Kannan Marudachalam
Vibrations have become an increasingly important attribute for determining the quality of automotive products. Particularly, this becomes more acute in the case of tactile vibrations of powered two-wheeler – motorcycles and scooters. This paper deals with vibrations of a scooter vehicle. Scooters are normally a two-wheeler with a four stroke single cylinder spark ignited engine. Vibrations of a scooter are mainly caused by the inertial imbalance forces of the engine, combustion forces and road undulations. Vibrations due to road undulations are mostly reduced by toggle link mechanism, resilient mounts of the engine and the shock absorbing suspension of the frame. The power train assembly is designed in such a way that the inertial imbalance forces in the power train assembly are distributed at a required angle called the ellipse angle.
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
2016-01-2355
Sivanesan M, Jayabalaji G
Analytical and numerical study is carried out to study the behavior of stick-slip and judder phenomenon during engaging and disengaging of the automotive clutch. For this, a four degree of freedom torsional power train lumped mass model is developed. This torsional vibration system includes engine-flywheel, clutch, gear box and vehicle drive line, which are connected to each other by shafts. Equation of motion of the system is developed and initially a stability analysis is carried out for various gradients of coefficient of friction using eigen value analysis. Later, a numerical simulation is carried out to analyze the judder and stick-slip phenomenon using commercially available mathematical tool MATLAB. It is observed that the clutch stick-slip is increased with increase in external torque and clutch pressure fluctuations.
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.
2016-10-17
Technical Paper
2016-01-2178
Daniela Siano, Gerardo Valentino, Fabio Bozza, Arturo Iacobacci, Luca Marchitto
In this paper, a downsized twin-cylinder turbocharged spark-ignition engine is experimentally investigated at test-bench in order to verify the potential to estimate the peak pressure value and the related crank angle position based on vibrational data acquired by an accelerometer sensor. Purpose of the activity is to provide the ECU of additional information to establish a closed-loop control of the spark timing, on a cycle-by-cycle and cylinder-by-cylinder basis. In this way, an optimal combustion phasing can be more properly accomplished in each engine operating condition. Vibrational data are also employed to have information on cycle-by-cycle variations (CCVs) of the pressure peak. More sophisticated techniques for the control of the cycle dispersion are also foreseen. To this aim, engine behavior is firstly characterized in terms of average thermodynamic and performance parameters and CCVs at high-load operation.
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
2016-01-2136
Oliver Pecat, Tebbe Paulsen, Philipp Katthöfer, Ekkard Brinksmeier, Sascha Fangmann
Insufficient chip extraction often leads to disruptions of automated drilling processes and degraded surface qualities. One opportunity to avoid chip accumulation is based on a cinematically enforced chip breakage caused by sinusoidal axial oscillations of the drilling tool. Recent investigations have shown that the quality of chip extraction is, amongst others, considerably depending on the chip shape and mass which are defined by the cutting parameters feed, amplitude and number of oscillation per revolution. So far only mechanical systems in the form of tool holders have been available on the market, which are restricted to a fixed number of oscillations per revolution (oscillation frequency is coupled to the spindle speed). In the present study a spindle with magnetic bearings was used which allows to adjust the oscillation frequency independently of the spindle speed and therefore enables all opportunities to affect the generated chip shapes.
2016-09-27
Technical Paper
2016-01-2097
Sylvain Laporte, Cosme De Castelbajac, Mathieu Ladonne
The Vibration Assisted Drilling (VAD) process has been implemented in Automated Drilling Units (ADU) on an industrial scale for almost a decade. Today more than 11000 ADUs are equiped with VAD systems and currently used on aircraft assembly lines. As well as drawing up a short report on the use of this new process, the authors make an assessment on new challenges that VAD has to face up. Indeed production rates are increasing and ADU manufacturers improve their technologies, one of the most recent and major development concerning the electrical motorization of the machines. These evolutions are as many opportunities for the VAD provided you have a clever understanding as well as an expert knowledge of the process. Thus the authors propose a new dynamic model of the whole VAD system which integrates the behavior of the part, cutting tool/material pair and the machine. The confrontation of model results and experimental validation tests demonstrates the relevance of the works.
2016-09-27
Technical Paper
2016-01-2096
Simon Schnieders, Dirk Eickhorst
Drilling of high-strength titan material and composites in combination creates complex challenges in order to achieve required productivity and quality. Long spiral chips are characteristically for the titan drilling process, which leads to e.g. chip accumulation, high thermomechanical load, surface damages and excessive tool wear. The basic approach is the substitution of today’s peck-drilling as current solution to this problem and the implementation of a vibration assisted drilling, so called micro-peck-drilling-process, to generate a kinematic chip breakage in a significant more efficient way. To meet perfectly the requirements regarding rates, quality and automation level, Broetje-Automation as system integrator has investigated and developed the implementation of different alternative high-performance systems and methods to approach the optimal oscillation movement of the tool.
2016-09-27
Technical Paper
2016-01-8121
Riccardo Bianchi, Addison Alexander, Andrea Vacca
Vibrations at the cabin or at the implements of construction machinery represents important drawbacks from the points of view of machine productivity, safety and operator comfort. Oscillations of these machines are particularly relevant due to the absence of shock absorbers, typical of many machines such as wheel loaders, and their use in uneven ground conditions. Several hydraulic solutions have been proposed in the past to reduce oscillations at both the cabin or at the machine boom. Particularly, cabin oscillations can be attenuated by properly counteracting the exciting oscillatory forces from the tires with motion of the boom. Many state of the art machine utilize a passive methods to implement this strategy. The present work introduces a novel active solution, based on the control of the boom actuator without involving modifications of the standard hydraulic system.
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.
2016-09-27
Technical Paper
2016-01-8116
Mrudula Uday Orpe, Monika Ivantysynova
Abstract Mobile Earth Moving Machinery like Skid-steer loaders have tight turning radius in limited spaces due to a short wheelbase which prevents the use of suspensions in these vehicles. The absence of a suspension system exposes the vehicle to ground vibrations of high magnitude and low frequency. Vibrations reduce operator comfort, productivity and life of components. Along with vibrations, the machine productivity is also hampered by material spillage which is caused by the tilting of the bucket due to the extension of the boom. The first part of the paper focuses on vibration damping. The chassis’ vibrations are reduced by the use of an active suspension element which is the hydraulic boom cylinder which is equivalent to a spring-damper. With this objective, a linear model for the skid steer loader is developed and a state feedback control law is implemented.
2016-09-27
Technical Paper
2016-01-8101
Yoshimune Mori, Akifumi Yoshimura, Nobutaka Tsujiuchi, Akihito Ito, Atsushi Fujimoto, Zenzo Yamaguchi, Koichi Honke
Abstract In a typical mechanical product such as an automobile or construction machinery, it is important to identify deformation modes, for which experiments and analyses can result in significant improvements. It is also important to consider how to improve the structure with high rigidity by using a technique such as the strain energy method in conventional design and development. However, the abovementioned method often generates conflicting results with regard to weight saving and cost reduction of development requirements. Transfer path analysis (TPA) using the finite element method (FEM) is an effective way to reduce noise and vibration in the automobile with respect to these issues. TPA can reveal the transfer path from the input to the response of the output point and the contribution of the path, and to efficiently consider improved responses.
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
2016-01-1933
Mingzhuo Li, Dejian Meng, Lijun Zhang
Brake judder severely affects the riding comfort and safety of vehicle. For the brake corner system, a rigid-flexible coupling model are established based on ADAMS. In the model, brake pads, caliper, anchor and knuckle are flexible body, and the contacts between pads and disc and the contact between pads and caliper are defined in detail. Meanwhile, the vibration acceleration of the brake corner components and the contact forces between disc and pads are used as evaluation index and the evaluation system of brake judder are improved. The analysis results show that the novel model and evaluation system can be used to predict brake judder effectively.
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
Technical Paper
2016-01-1920
Deaglan O'Meachair, Stamatis Angelinas, Matthew Crumpton, Antonio Rubio Flores, Juan Garcia, Pablo Barles
Bentley Motors Ltd. has developed a Carbon Silicon Carbide (CSiC) brake system for it’s Mulsanne product, introduced at 17MY. The CSiC brake system is conceived as a performance brake system, and as such offers notable improvements in brake performance In developing the brake system, particular focus was placed on meeting the refinement levels required for a premium product, and indeed as the flagship model for Bentley Motors, NVH refinement of the brake system was of particular concern. This paper intends to discuss the technical performance of the brake system and review the NVH performance of the brakes. This paper will also demonstrate the effect of vehicle isolation on the cabin NVH, and ultimately the passenger experience, by comparing the noise and vibration content in the wheel arch with that apparent to the driver.
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.
2016-09-18
Journal Article
2016-01-1931
Aaron Völpel, Georg Peter Ostermeyer
Abstract In today’s research and development of brake systems the model-based prediction of complex vibrations and NVH phenomena plays an important role. Despite the efforts, the high dimensional computational simulation models only provide a limited part of the results gained through experimental measurements. Several reasons are discussed by the industry and academic research. One potential source of these inadequacies is the very simple formulation of the friction forces in the simulation models. Due to a significant shorter computation time (by orders of magnitude), the complex eigenvalue analysis has been established, in comparison to the transient analysis, as the standard method in the case of industrial research, where systems with more than one million degrees of freedom are simulated.
2016-09-18
Journal Article
2016-01-1939
Toshikazu Okamura
Abstract Brake judder is one of the most serious problems in automotive-brake systems. It is basically a forced vibration caused by the friction-surface geometry of a brake disc, and therefore, disc rotors play a significant role in judder. There are two types of judder: cold and hot. Hot judder is caused by the thermo-mechanical deformation of a brake disc due to high-speed braking. There are several shapes of deformation, e.g., coning and circumferential waviness. Circumferential waviness is caused by thermo-mechanical buckling and typically found as a butterfly shape in a 2nd rotational-order and hot-spotting. In a previous paper, two groups of disc castings with different material homogeneity were machined intentionally to have two kinds of dimensional variations.
2016-09-18
Journal Article
2016-01-1911
Philippe Dufrenoy, Vincent Magnier, Yassine WADDAD, Jean-Francois Brunel, Gery DE SAXCE
Abstract During friction it is well known that the real contact area is much lower to the theoretical one and that it evolves constantly during braking. It influences drastically the system’s performance. Conversely the system behavior modifies the loading conditions and consequently the contact surface area. This interaction between scales is well-known for the problematic of vibrations induced by friction but also for the thermomechanical behavior. Indeed, it is necessary to develop models combining a fine description of the contact interface and a model of the whole brake system. This is the aim of the present work. A multiscale strategy is propose to integrate the microscopic behavior of the interface in a macroscopic numerical model. Semi-analytical resolution is done on patches at the contact scale while FEM solution with contact parameters embedded the solution at the microscale is used. Asperities and plateaus are considered at the contact interface.
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