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2015-04-14
Technical Paper
2015-01-1506
Bastian Scheurich, Tilo Koch, Michael Frey, Frank Gauterin
Today, body vibration energy of passenger cars gets dissipated by linear working shock absorbers. A new approach substitutes the damper of a passenger car by a cardanic gimbaled flywheel mass. The constructive design leads to a rotary damper in which the vertical movement of the wheel carrier leads to revolution of the rotational axis of the flywheel. In this arrangement, the occurring precession moments are used to control damping moments and to store vibration energy. A gyroscope is set to high speed revolutions by an electric motor and a gimbal is used for bearing. The gimbal consists of an outer ring which is connected to the vertical movement of the wheel carrier. Right-angled to the outer ring, there is an inner ring pivoting the gyroscope right-angled. In order to avoid undesirable body movements, the directional vector of the angular velocity of the gyroscope is parallel to the car’s yaw axis.
2015-04-14
Technical Paper
2015-01-0668
Yongchang DU, Pu Gao, Yujian Wang, Yingping Lv
The study and prevention of unstable vibration is a challenging task for vehicle industry. Improving predicting accuracy of braking squeal modal is of great concern. Closed-loop coupling disc brake model is widely used in complex eigenvalue analysis and further analysis. The coupling stiffness of disc rotor and pads is one of the most important parameters in the model. But in most studies the stiffness is calculated by simple static force-deformation simulation. In this paper, a closed-loop coupling disc brake model is built. Initial values of coupling stiffness are estimated from static calculation. Experiment modal analysis of stationary disc brake system with brake line pressure and brake torques applied is conducted. Then an optimization process is initiated to minimize the differences between modal frequencies predicted by the stationary model and those from test. Thus model parameters more close to reality are found.
2015-04-14
Technical Paper
2015-01-1326
Guru Prasad Mani, Sundaravadivelu M, Kavin Raja
Generation of discretization with prescribed element sizes are adapted to the geometry. From Rules of thumb, for a complicated geometry it is important to select the reasonable element order, shapes and size for accurate results. In order to that, this paper describes the influence of elemental algorithm of the catalytic converter mounting brackets. Brackets are main source of mounting of various systems mainly intake and exhaust in the engine .In exhaust hot end system, bracket designs play a vital role because it has to withstand heavy structural vibrations without isolation combined with thermal loads. Bracket design and stiffness determines the whole Catalytic converter system's rigidity. So, here discretization of converter brackets by linear and parabolic elements is studied with different elements types and compared.
2015-04-14
Technical Paper
2015-01-0666
Chenguang Li, Fue-sang Lien, Eugene Yee, Mike Dong
A deeper understanding of the complex phenomenology associated with the flow induced noise and vibration in a dynamic valve is of critical importance to the automotive industry. To this purpose, a two-dimensional axisymmetric numerical model has been developed to simulate the complex processes that are responsible for the noise and vibration in a poppet valve (or poppet). More specifically, an Eulerian multiphase flow model, a dynamic mesh and a user-defined function are utilized within the ANSYS-FLUENT software system in order to facilitate the modeling of the complicated two-phase fluid-structure interaction problem associated with the generation of noise and vibration in a poppet valve. In this strongly coupled simulation framework, the poppet valve which is driven by spring and various dynamical fluid forces (e.g., viscous and pressure forces), is modeled as an under-damped vibration system.
2015-04-14
Technical Paper
2015-01-1597
Kazuto Yokoyama, Masahiro Iezawa, Hideyuki Tanaka, Keiichi Enoki
Mitsubishi Electric has developed a concept car “EMIRAI 2 xEV” that features an electric vehicle (EV) powertrain for safe, comfortable, and eco-friendly driving experiences in the future. The body of vehicle was exhibited during Tokyo Motor Show 2013 for the first time. xEV is a four-wheel-drive EV that has three motors: a water-cooled front motor and two air-cooled rear motors with integrated inverters. Rear wheels can be driven independently. The degrees of freedom of the actuation can realize improved maneuverability and safety. The vehicle is also equipped with an onboard charger with built-in step down DC/DC converter, an EV control unit, a battery management unit, and an electric power steering. All of the instruments are developed in Mitsubishi Electric Corporation. Motion control systems for xEV have been developed on the basis of our proprietary original motor control technology.
2015-04-14
Technical Paper
2015-01-0610
Guangqiang Wu, Wenbo Luan
During the launch of a car, severe torsional vibration sometimes may occur in its driveline due to somewhat the slipping of the clutch, its intuitive sense for an occupant is the longitudinal vibration of the vehicle, referred to as the launch shudder, whose characteristic frequency is from 5 to 25 Hz generally. As the main vibratory sources of the driveline and its crucial nonlinear components, variable stiffness and backlash of the gear meshing are considered, their impacts on launch shudder are analyzed in this paper. Conformal mapping, finite element method and regression method etc. are the main approaches to calculate the variable meshing stiffness of a gear pair. If this stiffness is get, it can usually be substituted for its approximate analytical expression, or just with finite harmonic terms, in Fourier series form into Ordinary Differential Equations(ODEs) to calculate the vehicle responses considering its nonlinearity.
2015-04-14
Technical Paper
2015-01-1558
Amir Kharazi, Edward Duell, Austin Kimbrell, Ann Boh
Unsteady flow over automotive side-view mirrors may cause flow-induced vibrations of the mirror assembly which can result in blurred rear-view images, adversely affecting marketability and driver safety, as well as customer comfort and quality perception. Prior research has identified two mechanisms by which aerodynamically induced vibrations are introduced in the mirror. The first mechanism is unsteady aero pressure loading on the mirror face due to the unsteady wake, causing direct vibration of the mirror glass. The second mechanism, and the focus of this study, is a fluctuating loading on the mirror housing caused by an unsteady separation zone on the outer portion of the housing. A time-dependent Computational Fluid Dynamics (CFD) methodology to correctly model mirror wake behavior, and thereby predict flow-induced mirror vibration to improve performance estimations, was developed.
2015-04-14
Technical Paper
2015-01-1088
Tomohiko Usui, Tomoya Okaji, Tatsuya Muramatsu, Yoshiyuki Yamashita
A low-cost lock-up damper displaying a high level of damping performance has been developed for use in torque converters in automatic transmissions. The new damper was actualized by sharing parts (the turbine and damper components) and optimizing parameters for damping characteristics. The new torque converter displays equivalent conversion performance to a conventional model while reducing the width of the torus by approximately 30%. The combination of the lock-up damper and the small torus has made it possible to reduce torque fluctuation transmitted to the transmission to less than 50% with no increase in the overall width of the torque converter against a conventional model. This has reduced engine speed when the vehicle is cruising by 400rpm, resulting in an increase in fuel efficiency of approximately 2%.
2015-01-14
Technical Paper
2015-26-0127
Gaurav Paliwal, Naveen Sukumar, Umashanker Gupta, Saurav Roy, Hemantkumar Rathi
Abstract The main emphasis for a commercial vehicle design which was focused on fuel-economy and durability does not fulfill the increasing customer expectations anymore. Commercial vehicle designers need to focus on other vehicle aspects such as steering, ride comfort, NVH, braking, ergonomics and aesthetics in order to provide car like perception to truck, bus drivers and passengers during long distance drives. Powertrain mounting system must perform many functions. First and foremost, the mounting system must maintain & control the overall motion of the powertrain, to restrict its envelope reasonably, thereby avoiding damage to any vehicle component from the potential impact. This requires the mount to be stiff. Second the mount must provide good vibration isolation to have a comfortable ride to the vehicle occupant. This requires the mount to be soft.
2015-01-14
Technical Paper
2015-26-0128
MR Vikram, Ramesh Patil, Shashidhar Chattanahalli, Vijay H Meti
Abstract Automotive manufacturers are facing unprecedented cost challenges across globe. Market requirement has become very competitive with increased demand for higher performance and value engineering. This is encouraging automotive manufacturers to develop dampers with local suppliers, as there is a huge component cost advantage and also logistic cost savings. However, in emerging markets, supplier capability to develop the component for solving particular NVH problem of OEM is not matured as compared to developed market suppliers. The challenge for auto makers is to develop suppliers who can provide proper performance and durability, while at the same time providing lower cost components. This paper gives an overview of the challenges in the development process to develop a competitive torsional vibration damper for rear wheel drive vehicle to reduce boom noise and vibration.
2015-01-14
Technical Paper
2015-26-0214
Sivanandi Rajadurai, Guru Prasad Mani, Kavin Raja, Sundaravadivelu Mohan, Balaji Manivannan
Abstract Automotive exhaust system components are exposed to many types of vibrations, from simple sinusoidal to maximum random excitations. Computer-Aided engineering (CAE) plays an inevitable role in design and validation of hot vibration shaker assembly. Key Life Test (KLT), an accelerated hot vibration durability test, is established to demonstrate the robustness of a catalytic converter. The conditions are chosen such a way that the parts which passes key life test will always pass in the field, whereas the parts which fail in the key life test need not necessarily fail in the field. The hot end system and the test assembly should survive in these aggressive targeted conditions. The test fixture should be much more robust than the components that it should not fail even if the components fail. This paper reveals the computational methodology adopted to address the design, development and validation of the test assembly.
2015-01-14
Technical Paper
2015-26-0220
Sachin W. Thor, Shriniwas Chippa, Abhijit Majage
Abstract An automobile rear view mirror is attached at the side of the vehicle which is used to provide clear vision outside the vehicle. In the running condition of vehicle, various vibrations occur and are transferred to the mirror which may disturb driver's rear view. Since the vibration of mirror is related to safety consideration, it becomes essential to minimize it. Vibration analysis is very much important for the successful design and development of new parts in automobile. In present work, Vibration analysis of existing design of outside rear view mirror is investigated through numerical model using Finite Element Method (FEM). Furthermore, these results are verified through experimental work. From the modal analysis, it was found that the natural frequency of outside rear view mirror is less than the excitation frequency (Engine & Road excitation). However, to avoid resonance and for a safe design the natural frequency must be greater than these excitation frequencies.
2015-01-14
Technical Paper
2015-26-0154
Anand Ramalingam, Saravanakumar Thangamani
Abstract This paper discusses about the Flange design study carried out in Fuel Delivery Module (FDM) for meeting out contradictory requirements of robustness and crash worthiness. FDM is assembled in the fuel tank with flange covering the tank opening, and swirl pot assembly comprising fuel pump attached to flange through two steel struts. During crash, FDM undergoes sudden deceleration. Due to inertia, swirl pot assembly creates bending moment in the flange-strut interface. At such adverse condition, flange should not exhibit crack on the sealing side, as it might expose fuel in the fuel tank to the atmosphere. To ensure safety, flange-strut interface in the bottom side of flange is designed with higher stress concentration factor. So, the struts along with swirl pot assembly will break away from flange during crash without creating crack in the flange sealing faces.
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
2014-32-0123
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
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.
2014-10-13
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
2014-01-2849
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
2014-01-2703
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
2014-01-2862
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.
2014-09-30
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
2014-01-2314
John Stuart, Stefano Cassara, Brendan Chan, Nicholas Augustyniak
Wobble and shimmy vibrations are commonly observed in commercial highway vehicles with solid-beam front axles. These vibrations are typically self-excited and manifest themselves as sustained oscillations about the kingpin and axle tramp. A study was initiated to investigate and quantify wobble and shimmy behaviors, with a primary focus on wobble. A cross functional team including test and simulation engineers evaluated a vehicle exhibiting these behaviors. The team developed an ADAMS model to reproduce the behaviors and developed a DOE to quantify the impact of variables and combinations of variables. The evaluation demonstrated that dynamic imbalance in the rotating masses is a primary source of excitation. Wheel run-out, caster angle, tire brand, tire wear and tire inflation are also significant sources. Future studies will use these findings to mitigate the concern.
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.
2014-09-28
Technical Paper
2014-01-2513
Taeho Jung, Jeongkyu Kim
Abstract Rust accumulated on disc surfaces causes brake judder and grind noise. This paper deals with grind noise(wire brush brake noise) in vehicles which is a low frequency vibration and broadband noise problem at 100∼1kHz that appears in low vehicle speed. Recently, the customer complaints have increased for grind and creep groan noise more than squeal noise. Low frequency brake noise is a combined effect of brake and suspension systems working with each other. The noise transfer path is also important. Experimental results are confirmed through ODS, Modal, TPA and 3D acoustic camera for noise transmission path. Finally, reduction methods of grind noise are presented.
Viewing 1 to 30 of 2196

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