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Viewing 61 to 90 of 8756
2015-01-14
Journal Article
2015-26-0131
Abhishek Verma, M. L. Munjal
Abstract In this work, the noise attenuation characteristics of a three-chamber U-bend hybrid muffler have been investigated. Acoustic performance is quantified by the Transmission Loss (TL) parameter. One-dimensional Transfer Matrix based Muffler Program (TMMP) and three-dimensional Finite Element Method (FEM) have been used for the prediction of the TL of the muffler. Presence of perforated baffles necessitates use of the Integrated Transfer Matrix (ITM) approach for the one-dimensional analysis because the sound fields in the adjacent chambers would be multiply coupled with each other, and for the 3D FEM analysis LMS Virtual Lab software has been used. The mean flow distribution in each of these configurations has been evaluated by means of a lumped flow resistance network. The resulting values of the grazing flow and bias flow have been used to calculate the perforates' acoustic impedance.
2015-01-14
Journal Article
2015-26-0136
Deepak Mahajan, Arnab Sandilya, Lokesh Khandelwal, Sameer Srivastava
Abstract Automotive floor carpet serves the purpose of insulating airborne noises like road-tire noise, transmission noise, fuel pump noise etc. Most commonly used automotive floor carpet structure is- molded sound barrier (PE, vinyl etc.) decoupled from the floor pan with an absorber such as felt. With increasing customer expectations and fuel efficiency requirements, the NVH requirements are increasing as well. The only possible way of increasing acoustic performance (Specifically, Sound Transmission Loss, STL) in the mentioned carpet structure is to increase the barrier material. This solution, however, comes at a great weight penalty. Theoretically, increasing the number of decoupled barrier layers greatly enhances the STL performance of an acoustic packaging for same weight. In practice, however, this solution presents problems like- ineffectiveness at lower frequencies, sudden dip in performance at modal frequencies.
2015-01-12
Article
3-D laser scanning from NVision helped a certified FAA repair station document its work on a passenger jet part with such precision that the station was able to obtain the necessary FAA approval for the repair in much less time than is usually required.
2015-01-02
Article
Flight testing is being conducted at NASA's Armstrong Flight Research Center in Edwards, CA, to determine whether flexible trailing-edge wing flaps are a viable approach to improve aerodynamic efficiency and reduce noise generated during takeoffs and landings.
2014-12-29
Standard
J2889/1_201412
This SAE Standard is derived from SAE J2805 and specifies an engineering method for measuring the sound emitted by M and N category road vehicles at standstill and low speed operating conditions.. The specifications reproduce the level of sound which is generated by the principal vehicle sound sources consistent with stationary and low speed vehicle operating conditions relevant for pedestrian safety. The method is designed to meet the requirements of simplicity as far as they are consistent with reproducibility of results under the operating conditions of the vehicle. The test method requires an acoustic environment which is only obtained in an extensive open space or in special designed indoor facilities replicating the conditions of an extensive open space. Such conditions usually exist during: Measurements of vehicles for regulatory certification. Measurements at the manufacturing stage. Measurements at official testing stations.
2014-12-23
Article
The potential impact to public health from GDI engine particulates is driving new developments in fuel delivery, controls, and combustion strategies.
2014-12-18
Article
Teledyne LeCroy has added unique measurement and graphing capabilities to its CAN flexible data-rate serial trigger and decode solution.
2014-12-18
WIP Standard
J1281
This SAE Recommended Practice establishes the procedure for assessing operator sound level exposure for pleasure motorboats under 20 m (65 ft) in length when operated under typical conditions, and describes the instrumentation, test site, and boat operation for making valid measurements.
2014-12-17
Article
HBM has introduced three new amplifier modules for its SomatXR data acquisition system.
2014-12-12
Article
With the actuator sensor manipulation (ASM) box, FEV Group provides a powerful tool for manipulation of the signal exchange between actuators and an engine control unit .
2014-12-12
Article
PC-DMIS 2014.1 from Hexagon Metrology is a significant update of measurement software used for the collection, evaluation, management, and presentation of manufacturing data.
2014-12-10
Article
Using advanced supercomputers and the largest X-ray imaging system in the western hemisphere, the team of researchers developed and validated software models for fuel injectors. One the most difficult to understand engine phenomenon, these validated models are useful for simulating fuel injectors and are now available to engine developers.
2014-12-02
Article
Toyota today called for a coordinated industry-wide joint initiative to independently test Takata airbag inflators that have been the subject of recent recalls by several automakers. "By combining our collective efforts behind a coordinated, comprehensive testing program, we believe we can achieve greater results.
2014-11-26
Article
High-tech design causes time to remanufacture engines to nearly triple and adds to cost, while used engines remain a competitive factor. However, Purdue University data shows remanufacturing is far more energy efficient than installing a new powerplant.
2014-11-25
Article
Ophir Photonics’ 1000WP-BB-34 high-power water cooled thermal sensor is designed with the requirement that all materials coming in contact with the cooling water are either copper or nonmetallic.
2014-11-24
Article
SEMA develops step-by-step system in conjunction with California Air Resources Board to help participating members comply with emissions regulations. Clemson University I-CAR is an active participant, providing laboratory facilities for analysis to aid SEMA members who are aftermarket manufacturers.
2014-11-23
WIP Standard
AS8040C
This SAE Aerospace Standard (AS) covers combustion heaters used in the following applications: a. Cabin heating (all occupied regions and windshield heating) b. Wing and empennage anti-icing c. Engine and accessory heating (when heater is installed as part of the aircraft) d. Aircraft de-icing
2014-11-12
Article
A Level 2 electric vehicle charger that can dispense power based on the available grid supply is undergoing its first field test in Detroit.
2014-11-11
Technical Paper
2014-32-0026
Alessandro Franceschini, Emanuele Pellegrini, Raffaele Squarcini
Abstract Nowadays the challenge in design of auxiliary devices for automotive small engines is focused on packaging reduction and on the increase of the performance. These requirements are in contrast to each other and in order to fulfil the project specifications, new and more refined design tools and procedures need to be developed. This paper presents a calculation loop developed by Pierburg Pump Technology Italy S.p.A. (PPT). It supports the design of a variable displacement oil pump component for engine applications. The work is focused on the fatigue life evaluation of a joint, which transmits the drive torque from the engine to the oil pump. The aim of the procedure is to calculate the onset of the surface fatigue phenomenon in the hexagonal joint which drives the oil pump, taking into account the axes misalignment and the flat-to-flat clearance. The study has involved several matters, experimental measures, CFD, MBA and FEM analyses.
2014-11-11
Technical Paper
2014-32-0063
Daniela Siano, Fabio Bozza, Danilo D'Agostino, Maria Antonietta Panza
Abstract In the present work, an Auto Regressive Moving Average (ARMA) model and a Discrete Wavelet Transform (DWT) are applied on vibrational signals, acquired by an accelerometer placed on the cylinder block of a Spark Ignition (SI) engine, for knock detection purposes. To the aim of tuning such procedures, the same analysis has been carried out by using the traditional MAPO (Maximum Amplitude of Pressure Oscillations) index and an Inverse Kinetic Model (IKM), both applied on the in-cylinder pressure signals. Vibrational and in-cylinder pressure signals have been collected on a four cylinder, four stroke engine, for different engine speeds, load conditions and spark advances. The results of the two vibrational based methods are compared and in depth discussed to the aim of highlighting the pros and cons of each methodology.
2014-11-11
Technical Paper
2014-32-0061
Rama Subbu, Baskar Anthony Samy, Piyush Mani Sharma, Prasanna Mahendiran
Abstract Ride comfort, driving stability and drivability are vital factors in terms of vehicle performance and customer satisfaction. Crankshaft unbalance is a source for the vibration that reduces the vehicle performance and it needs to be controlled to some extent such that the vehicle performance will be improved. The IC engine is made up of reciprocating and rotating parts. They produce unbalance forces during their operation and produces vibration in Vehicle. The vibration reduction will be possible by minimizing these unbalance forces and by optimizing the crankshaft of the two wheeled vehicle engine design. Many researches were made to find the causes for the vibration and to reduce it. But still there is a research gap on the testing and simulation of engine components (crankshaft, connecting rod and piston assembly). In this study, an attempt is made to represent the engine vibrations and its isolation to provide a gate way for the future work on it.
2014-11-11
Technical Paper
2014-32-0047
Mohamed El Morsy, Gabriela Achtenova
Abstract Using the PULSE platform for vibration analysis, which has been developed as an advanced solution for vibration measurements, the Robust Diagnostic Concept (RDC) was elaborated. The PULSE setup is designed to aid in fault diagnosis of a vehicle gearbox - the main part of a vehicle powertrain. Time Domain, Continuous Wavelet Transformation Technique (CWT), FFT and order analysis measurements are used for detection of an artificial pitting defect in a gear by tracking the gearbox response at accelerated speed and different loads. The test stand is equipped with three dynamometers; the input dynamometer serves as the internal combustion engine, the output dynamometers introduce the load on the flanges of the output joint shafts. The pitting defect is manufactured on the tooth side of the fifth speed gear on the intermediate shaft. The effect of temperature on the vibration measurements was also investigated to study its impact on the fault diagnosis.
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
2014-32-0120
Sara Gronchi, Riccardo Maccherini, Raffaele Squarcini, Fabio Guglielmo, Emanuela Ligarò
Abstract In the modern engine of both small and large size, the acoustic emission is a very important matter increasingly studied as per specific international standards. This paper presents the study of the acoustic emission of a hydraulic rotary oil pump by means of measurement techniques and numerical approaches. This activity aims at showing a complete test-case in which both methods are used to face a noise issue and highlighting also the “weight” of the hydraulic excitation in both cases. In particular, an oil pump has been completely characterized on a test bench to verify the hydraulic performances and the noise radiation. A structural modification has been suggested with the target of altering the noise spectrum of the pump, achieving an optimization of the noise generation. From this assumption, experimental and numerical activities have started in parallel.
2014-11-11
Technical Paper
2014-32-0123
Vishnu Kumar Kuduva Shanthulal, Kannan Marudachalam, V Pattabiraman, S Jabez Dhinagar, Chandramouli Padmanabhan
Abstract The diesel power train (engine and transmission) is the most significant mass contributor in a three- wheeled vehicle. High idling vibrations from the engine get transmitted to the structure and the body panels through the engine mounts. Isolation of these vibrations by proper design of rubber mounts is the most effective engineering approach to improve ride quality of vehicle. In the present study, a mathematical model of the powertrain and mount system is developed; with the engine and transmission being assumed to behave as a rigid body (6 degrees-of-freedom) and the compliance comes from the mounts. As a first step, the modes and natural frequencies are obtained. Following this the response to unbalanced inertial forces for an excitation frequency range of 20-60 Hz (1200-3600 rpm) has been obtained. The model is validated by comparing its results with results of previous published research work.
2014-11-11
Technical Paper
2014-32-0121
Kazuhiko Tanaka, Haruomi Sugita, Hibiki Saito, Masahiko Sekita
Abstract Recently, it has been widely practiced in motorcycle developments that the same type of engine is commonly applied to various vehicle categories. Accordingly, it is drawing more attention to develop the methodology for creating the best suitable sound for each individual vehicle category regardless of restriction from the engine configurations. In our study, we aimed to establish a procedure to control exhaust sounds beyond the borders across the inherent sound qualities originated from their engine configurations. Firstly, we conducted subjective tests in order to extract essential factors, depicted by adjectives that appear in verbal expressions commonly used to illustrate sound qualities in general. The results enabled us to conduct quantitative evaluations of the exhaust sound qualities of various motorcycles. Next, we clarified the relationships among the individual factors of sound qualities under our study and physical parameters in waveforms of the sounds.
2014-11-11
Technical Paper
2014-32-0129
Giancarlo Chiatti, Erasmo Recco, Ornella Chiavola, Silvia Conforto
Abstract In the last years, the increasing concern for the environmental issues of IC engines has promoted the development of new strategies capable of reducing both pollutant emissions in atmosphere and noise radiation. Engines can produce different types of noise: 1) aerodynamic noise due to intake and exhaust systems and 2) surface radiated noise. Identification and analysis of noise sources are essential to evaluate the individual contribution (injection, combustion, piston slap, turbocharger, oil pump, valves) to the overall noise with the aim of selecting appropriate control strategies. Previous paper focused on the combustion related noise emission. The research activity aimed at diagnosing and controlling the combustion process via acoustic measurements. The optimal placement of the microphone was selected, where the signal was strongly correlated to the in-cylinder pressure development during the combustion process.
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.
2014-11-11
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.
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