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Viewing 31 to 60 of 8703
2014-11-11
Journal Article
2014-32-0119
Diego Copiello, Ze Zhou, Gregory Lielens
Abstract This paper addresses the numerical simulation of motorcycle exhaust system noise using a transfer matrix method (TMM) supporting high order analytical acoustic modes representation combined with finite element method (FEM) included in the Actran software, R15. In the state-of-the-art of hybrid TMM/FEM approach the main assumption consists in a 1D plane wave acoustic propagation in the components connections which is intrinsically limiting the maximum frequency of the analysis. In motorcycle exhaust systems this limitation is even stronger because typical geometries exhibit strong curvatures and bends causing the scattering of the acoustic wave into higher order modes. Therefore, results might be erroneous even at frequencies at which only the plane wave is expected to be propagating. The improved transfer matrix method presented in this paper overcomes this limitation allowing to increase the range of applicability of this method.
2014-11-11
Journal Article
2014-32-0018
Kenichi Morimoto, Kenichi Tanaka
Abstract There have been a number of attempts to clarify the relationship between motorcycle specifications and shimmy phenomenon. Some of such efforts are based on equations of motion. The methods used in those efforts are suitable for analyzing motions in a fundamental structure. However, when the degree of freedom is large, it is extremely difficult to deliver an equation of motion. Therefore, a practical method cannot be found generally when applying the methods employing equations of motion. We also conducted the analysis of shimmy using multi-body dynamics simulation. The yielded results were useful only for clarifying the differences in shimmy levels among motorcycles. However, they were not helpful to understand the relationships between specifications and shimmy phenomenon.
2014-11-11
Journal Article
2014-32-0053
Yoshihiro Nakagawa, Shinya Takahashi, Mikihito Masaki, Ranju Imao
Abstract In brake squeal analyses using FE models, minimizing the discrepancies in vibration characteristics between the measurement and the simulation is a key issue for improving its reproducibility. The discrepancies are generally adjusted by the shape parameters and/or material properties applied to the model. However, the discrepancy cannot be easily adjusted, especially, for the vibration characteristic of the disc model of a motorcycle. One of the factors that give a large impact on this discrepancy is a thermal history of the disc. That thermal history includes the one experienced in manufacturing process. In this paper, we examine the effects of residual stress on the natural frequency of motorcycle discs. The residual stress on the disc surface was measured by X-ray stress measurement method. It was followed by an eigenvalue analysis. In this analysis, we developed a unique method in which the residual stress was substituted by thermal stress.
2014-11-11
Technical Paper
2014-32-0105
Atsushi Maruyama, Gaku Naoe
Abstract For a small general purpose engine, the authors have studied on “combustion noise”, the mechanical noise originating from combustion. The purpose of this study is to clarify the mechanisms of combustion noise generation. The engine used in this study was a 4-stroke air-cooled single-cylinder engine with the typical characteristics of 3.5 kW-class small general purpose engines, which was specifically designed for experiments. We analyzed the operational behaviors of parts such as the crankshaft, the flywheel and the crankcase during the time of occurrence of combustion noise. Results of the analysis showed that the primary component of combustion noise in small general purpose engines is radiated from the flywheel connected to the crankshaft, and that the vibration mode that radiates the noise is excited by bending deformation of the crankshaft under explosion load.
2014-11-11
Technical Paper
2014-32-0132
Hiroki Ikeda, Norimasa Iida, Hiroshi Kuzuyama, Tsutomu Umehara, Takayuki Fuyuto
Abstract A combustion method called Noise Canceling Spike (NC-Spike) Combustion [1, 2] has been reported in the co-author's previous paper, which reduces combustion noise in PCCI with split injection. This NC-Spike Combustion uses interference of the following “spike” of pressure rise on the preceding peak of pressure rise. The overall combustion noise is reduced by lowering the maximum frequency component of the noise spectrum. The period of this frequency is two times of the time interval between the two peaks of the pressure rise rate. This maximum load range of conventional PCCI combustion is limited by the combustion noise, since the maximum pressure rise rate increases as the amount of injected fuel increases. The NC-Spike Combustion has a potential to extend of the operating range of PCCI combustion.
2014-10-31
WIP Standard
MA3433A
No scope available.
2014-10-29
Article
NASA and Aerojet Rocketdyne have successfully completed a series of hot-fire tests on an advanced rocket-engine thrust chamber assembly using copper alloy additive manufacturing technology. Full-scale demonstration is the next step in the technology’s development path.
2014-10-22
Book
The new Bosch Automotive Handbook, now in its 9th English edition, has been completely revised and enhanced to include the most recent developments in automotive technology. About 200 specialist authors contributed to this new version of every engineer’s must-have reference. The book's format has been revised: it is now 20 percent longer and wider, as this allows for a larger font size. This makes the texts and graphics easier to read. The index has been strongly expanded to make looking up technical terms easier. The Bosch Automotive Handbook is a best-seller, with a broad global readership. Students of engineering programs consult it, as do researchers and engineers in the automotive industry. Mechanics who are studying to become master craftsmen also use it as a reference work. Experts trust the well-founded and extensive expertise that can be found in the classic. The Bosch Automotive Handbook is widely regarded around the world as a standard work for automotive technology.
2014-10-20
Article
Meeting the cleanest emissions regulations ever with the phase-in of the Tier 4 Final and Stage IV imposed a new way to design and calibrate off-highway engines.
2014-10-20
Article
GP:50 Corporation LTD’s Model 188/288/388 miniature flush diaphragm pressure transducer series’ unique flush diaphragm design makes possible accurate pressure measurements of high-viscosity fluids, even within high shock and vibration environments, without port plugging and clogging.
2014-10-17
Article
Supercritical Fluid Technologies’ bench top supercritical fluid extractor, the model SFT-110, provides an alternative to traditional extraction methods that use organic solvents.
2014-10-17
Article
W. L. Gore & Associates is expanding its family of high-speed data cables for the aerospace industry to meet the industry’s challenges to improve pilot communication and passenger in-flight entertainment while reducing downtime for maintenance and decreasing operating costs.
2014-10-17
Article
The OM-WLS-TEMP series wireless USB 2.0 full-speed temperature input module from Omega is fully compatible with both USB 1.1 and 2.0.
2014-10-17
Article
WITT-Gasetechnik’s dome-loaded pressure regulator is impervious to system pressure and withdrawal fluctuations.
2014-10-13
Article
Researchers at VE Commercial Vehicles Ltd. in India employed downsizing to design a commercial vehicle exhaust system using the ANSYS CFD tool Fluent, resulting in a 14.1% reductions in both size and volume and a mass savings of 2%.
2014-10-13
Technical Paper
2014-01-2703
Xiuliang Zhao, Yong Cheng, Limei Wang
Abstract The surface vibration signals are widely used since they have much combustion information. However, for an Internal Combustion Engine (ICE), the measured surface vibration signals are difficult to utilize because they contain non in-cylinder pressure excitation response. The vibration response signals excited by the in-cylinder pressure excitation (ICPE) and the reciprocating inertia force excitation (RIFE) are overlapped in both time and frequency domain. That means they cannot be separated effectively by conventional signal processing method. In this paper, a new strategy to extract ICPE response from measured vibration signals by pattern recognition method is proposed. A model is established to describe the RIFE response. Then, the RIFE response could be predicted and subtracted directly from the measured vibration velocity signals. The processing results indicate that a fourth-order model and the data of initial compression stroke can reach satisfactory results.
2014-10-13
Journal Article
2014-01-2676
Takayuki Fuyuto, Masahiro Taki, Reiko Ueda, Yoshiaki Hattori, Hiroshi Kuzuyama, Tsutomu Umehara
Abstract An author's previous studies addressed a combustion system which reduces emissions, noise, and fuel consumption by using PCCI with the split injection of fuel. This concept relies on the premixed combustion of the first injected fuel and accelerated oxidation by the second injected fuel. Although this combustion system requires the optimization of the timing of the second injection, the details of how noise and emissions are reduced have not been elucidated. In this paper, the authors explain the mechanism whereby emissions and noise are reduced by the second injection. In-cylinder visualizations and numerical simulations both showed an increase in smoke and CO as the second injection timing was advanced, as induced by the inhibited oxidation of the rich flame. When the second injection timing is excessively retarded, the amount of soot forming around the near-nozzle increased.
2014-10-13
Technical Paper
2014-01-2849
Wei Guo, Henry Guo, Xiaowei Du, Daniel Wang
Turbochargers are widely used to boost internal combustion engines for both on and off high way applications to meet emission and performance requirements. Due to the high operating temperature, turbochargers are subjected to hostile environment. Low vibration level is one of the key requirements while designing turbo for every application. An engine bracket is employed to support turbine housing to reduce total vibration level. Turbine housing in the turbocharger is commonly equipped with boss to accommodate the engine bracket supporting which eventually includes additional constraints in the turbocharger system. Additional constraints in the turbine housing can lead to adverse impact in the Thermo-Mechanical Fatigue (TMF) life of the housing component. Boss generally has critical influence to thermal stress distribution of the turbine housing.
2014-10-13
Technical Paper
2014-01-2863
Jouji Kimura, Shinichiro Kobayashi, Katsuhiro Hoshina, Kousuke Kawase, Koji Matsui, Atsushi Yamamoto
Abstract This paper describes the characteristics and mechanism of crankshaft impact noise that radiates from the cylinder body at full load medium engine speeds, based on the mechanism for axial vibration of crankshaft coupled with torsional vibration of crankshaft.
2014-10-13
Technical Paper
2014-01-2867
Zhiyong Chen, Zhiyuan Chen, Yang Mao, Wenku Shi, Guihui Zhang
Abstract To research the torsional vibration damping characteristic of magneto-rheological fluid dual mass flywheel (MRF-DMF) and the control system in power train, the multi-degree power train torsional vibration model which contains MRF-DMF and semi-active fuzzy control model are built, then the damping characteristic of MRF-DMF in several conditions are gained and compared with MRF-DMF when no control system. The result indicates: the damping characteristic of MRF-DMF effect on power train when using control is better than without control in idle, speed up, slow down, ignition and stalling, while the damping characteristic is less obvious in constant speed because the simulation condition and damping moment relatively stable.
2014-10-13
Technical Paper
2014-01-2870
Yuan Fang, Tong Zhang
Abstract Because of the vehicle market competitive and of the raise of customers' demanding, NVH performance became an important job, especially for new energy vehicles. As the electric vehicle moving into the direction of high speed and large torque, electric vehicle vibration and noise problems highlighted gradually. In recent years, CAE has played an increasing role in the design, development and optimization of powertrain NVH at component and system levels. The subject of this paper was the numerical and experimental evaluation of the electromagnetic and vibro-acoustic behavior of an electric powertrain. For this purpose, a coupled and fully flexible dynamics model of the electric powertrain was developed.
2014-10-13
Journal Article
2014-01-2864
Daniela Siano, Fabio Bozza, Luigi Teodosio, Vincenzo De Bellis
This paper reports 1D and 3D CFD analyses aiming to improve the gas-dynamic noise emission of a downsized turbocharged VVA engine through the re-design of the intake air-box device, consisting in the introduction of external or internal resonators. Nowadays, modern spark-ignition (SI) engines show more and more complex architectures that, while improving the brake specific fuel consumption (BSFC), may be responsible for the increased noise radiation at the engine intake mouth. In particular VVA systems allow for the actuation of advanced valve strategies that provide a reduction in the BSFC at part load operations thanks to the intake line de-throttling. In these conditions, due to a less effective attenuation of the pressure waves that travel along the intake system, VVA engines produce higher gas-dynamic noise levels.
2014-10-13
Journal Article
2014-01-2862
Georg Johann Meingaßner, Hermann Pflaum, Karsten Stahl
Downsizing and downspeeding are currently important development approaches of the automobile industry to improve fuel efficiency and to reduce emissions. Decreased operational speeds in combination with higher combustion pressures lead to an increase of the excitation of torsional vibrations by the combustion engine. Torsional vibrations in powertrains can cause strength and NVH problems as well as lower driving comfort and reliability of the vehicle. Currently, conventional systems for reduction of torsional vibrations are increasingly reaching their limits. In cooperation with several institutes of the Technische Universität München (TUM) innovative concepts for an improved reduction of torsional vibrations in automotive powertrains have been developed.
2014-10-02
Article
The U. S Department of Transportation/NHTSA Vehicle Research and Test Center has commissioned dSPACE to supply an in-lab GPS simulation system. GPS simulation is used in the development and testing of numerous intelligent driving and traffic systems, including collision avoidance, advanced driver-assistance systems, navigation, and V2X communications.
2014-10-01
Journal Article
2014-01-9029
Uday Nayak, S Aravind, Sunil Aundhekar
Abstract The present competitive market scenario and customer requirements demand for improved NVH quality and to meet statutory norms without increased cost. When gears are used for power transmission, gear noise is of particular concern. The noise may be created due to harmonics of the rotating and meshing internal components. This has a significant effect on the overall vehicle sound quality. Various factors contribute to gearbox noise. Some of them include shaft misalignments, gear geometry, lubrication, bearings and loose mountings. Hence it is essential to study which factors contribute to the gearbox noise and to develop countermeasures for the same. Although a number of factors may contribute to gear noise as mentioned, the scope of this paper is limited to the effect of gear geometry alone on the gearbox noise.
2014-09-30
Article
The Model T261 series rotary transformer coupled torque sensors from SensorData Technologies meet the demanding in-line testing requirements of small motors, pumps, compressors, turbines, fans, and other fractional horsepower rated devices.
2014-09-30
Technical Paper
2014-01-2316
Masahiro Akei, Takayuki Koizumi, Nobutaka Tsujiuchi, Takayuki Yamauchi
Abstract This paper describes a prediction of vibration and the transfer path analysis (TPA) using an engine multi body dynamics (MBD) model and measured frequency response functions (FRFs). TPA is used in order to analyze each contribution of vibration transfer paths. In the TPA, input forces from vibration source to passive part should be identified accurately. In the traditional TPA, an identification of input forces is done using only experimental results. Therefore, a parametric study to an improvement of a structure or an isolation system is impossible. In this study, the MBD model of engine is constructed, and input forces from engine to mainframe of agriculture machine are predicted. The accuracy of prediction is confirmed, compared with the results from the traditional TPA method. The contribution of each transfer path is analyzed, and the vibration levels of operator position are predicted using the measured FRFs and the simulated input forces.
2014-09-30
Technical Paper
2014-01-2317
Rahul Ramola, G Senthilkumar, P Kannan, Muralidharan Chennakrishnan
Abstract The demand for comfort level in commercial vehicles is steadily increasing. Hence, fine-tuned performance parameters and attributes are required to fulfill the expectations from these vehicles. Refinement of noise and vibration without affecting performances of sub-systems and components has become extremely challenging with increasing customer requirements. This paper presents an approach to identify and reduce the high level whistling noise that was perceived in the passenger compartment while the vehicle was accelerated above 50 kmph. Interior noise measurements in static engine run-up condition reveal that the whistling noise is of specific order. Since, whistling noise is related to aerodynamic response of components, engine cooling fan, turbo charger, alternators and compressors were suspected. Using order tracking and near field measurements, HVAC alternator was confirmed as the main cause for whistling noise.
2014-09-30
Journal Article
2014-01-2318
Masahiro Akei, Takayuki Koizumi, Nobutaka Tsujiuchi, Takayuki Yamauchi
Abstract This paper describes an identification of a sound source model for a diesel engine installed on an agricultural machine by Inverse-Numerical Acoustic analysis (INA), and the applicability of the identified sound source model. INA is a method to identify surface vibrations from surrounding sound pressures. This method is applicable for a complicated-shaped sound source like an engine. In order to confirm the accuracy of the identified sound source model, the surface vibrations of the engine are compared with the measured results. Moreover, in the condition of the simulated engine room, the surrounding sound pressure levels of the engine are predicted using the sound source model and the boundary element method (BEM). For the verification of the prediction accuracy, the surrounding sound pressures of the engine are measured using the testing device which simulated actual engine room, namely an enclosure.
2014-09-30
Journal Article
2014-01-2315
John Anderson
Abstract This paper describes the development and testing of a Dynamic Vibration Absorber to reduce frame beaming vibration in a highway tractor. Frame beaming occurs when the first vertical bending mode of the frame is excited by road or wheel-end inputs. It is primarily a problem for driver comfort. Up until now, few options were available to resolve this problem. The paper will review the phenomenon, design factors affecting a vehicle's sensitivity to frame beaming, and the principles of Dynamic Vibration Absorbers (AKA Tuned Mass Dampers). Finally, the paper will describe simulation and testing that led to the development of an effective vibration absorber as a field fix.
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