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2014-04-01
Technical Paper
2014-01-1269
Julie Blumreiter, Chris Edwards
Abstract There is significant motivation to extend the operating range of naturally aspirated HCCI combustion to high load (8-12 bar IMEP) to attain a combustion strategy with the efficiency benefits of HCCI but without the lost power density of a lean or highly diluted charge. Currently, the high-load limit of HCCI combustion is imposed by a phenomenon commonly known as ringing. Ringing results when the kinetically-driven autoignited combustion process proceeds in such a way as to form strong pressure waves which reverberate in the engine. Inhomogeneities and gradients in mixture reactivity lead certain regions to react ahead of others, and as a result, coupling can occur between a pressure wave and the reaction front. This paper seeks first to sort several related but distinct issues that impose the high load limit: ringing, engine damage, peak in-cylinder pressure, peak rate of pressure rise, and engine noise. The fundamental gasdynamics underlying the upper load limit for premixed, autoignited engines are explored and elucidated with a quasi-1D reacting compressible flow model.
2014-04-01
Technical Paper
2014-01-1708
Xiaoxun Chen, Yu Zhang, Yunqing Zhang, Ming Jiang
Abstract In the present study, the research of the exhaust system is performed in three steps. In the first step, the average driving degree of freedom displacement (ADDOFD) is calculated by the free modal analysis of the exhaust system. It is easy to find the reasonable location of the hanger according to the value of the ADDOFD, since it represents the relative size of some DOF's response displacement at excitation state. The second of which is to analyse the vibration isolation performance of the exhaust system based on the first step. The dynamic analysis of the exhaust system together with the powertrain is studied, by which way the unit sinusoidal excitation is applied at the powertrain's mass centre, so that the response force at the hanger can be obtained. Finally, the relationship between the constrained model of the exhaust system and the stiffness of the hanger is investigated, which is significant in engineering.
2014-04-01
Technical Paper
2014-01-1700
Xiaobing Liu, Paul Nahra, Anna Strehlau
Abstract Engine stop/start systems are one technology being developed to meet ever tightening fuel economy regulations. Several production vehicles in the market have adopted stop/start systems with 12 volt batteries and enhanced starters. During engine autostart events (restart after autostop), the engine/vehicle vibration may be objectionable to customers. In this paper, the impact of extended range retarded intake cam phasing on first cycle combustion and vehicle vibration during engine autostart is provided. The engine intake cam phasers of a production vehicle were modified so the effective compression during autostart could be set as low as 3.5. Achieving these autostart conditions while maintaining typical cam timing positions under cold start conditions is achievable with an innovative dual park phaser. NVH measurements and engine speed traces indicate that this approach reduced vibration during engine autostart by a measurable amount. Subjective driver feedback was also positive.
2014-04-01
Technical Paper
2014-01-1693
Daniela Siano, Luigi Teodosio, Vincenzo De Bellis, Fabio Bozza
Abstract The present paper reports 1D and 3D CFD analyses of the air-filter box of a turbocharged VVA engine, aiming to predict and improve the gas-dynamic noise emissions through a partial re-design of the device. First of all, the gas-dynamic noise at the intake mouth is measured during a dedicated experimental campaign. The developed 1D and 3D models are then validated at full load operation, based on experimental data. In particular, 1D model provides a preliminary evaluation of the radiated noise and simultaneously gives reliable boundary conditions for the unsteady 3D CFD simulations. The latter indeed allow to better take into account the geometrical details of the air-filter and guarantee a more accurate gas-dynamic noise prediction. 3D CFD analyses put in evidence that sound emission mainly occur within a frequency range of 350 to 450 Hz. Starting from the above result, the original air-box design is modified through the installation of a single Helmholtz resonator, taking into account layout constraints and the influence on engine performance, as well.
2014-04-01
Technical Paper
2014-01-1691
George Nerubenko
Abstract The results of dynamical study of new patented Torsional Vibration Damper for an engine crankshaft are presented. Design and structure of Torsional Vibration Damper is based on author's US Patent 7,438,165 having the control system with instantaneous frequencies tuner for all frequencies in running engine. Basically the tuner should be designed in three optional manners: having mechanical structure, electromechanical structure with control system and micro-channels filled by electrolyte solution. The focus of the study is on Torsional Vibration Damper equipped with micro-channels filled by electrolyte solution. Mathematical model based on the system of ordinary differential equations describing the rotation and vibration of mechanical components combined to Navier-Stokes equations reflecting the fluid flow and Poisson - Boltzmann equations applicable for electrolyte solution flow in micro-channels has been used for the analysis of the dynamic behavior of engine crankshaft system having proposed Torsional Vibration Damper.
2014-04-01
Technical Paper
2014-01-1692
Mehdi Safaei, Shahram Azadi, Arash Keshavarz, Meghdad Zahedi
Abstract The main end of this research is the optimization of engine sub-frame parameters in a passenger car to reduce the transmitted vibration to vehicle cabin through DOE method. First, the full vehicle model of passenger car including all its sub-systems such as engine, suspension and steering system is modeled in ADAMS/CAR and its accuracy is validated by exerting swept sine and step input. After that, the schematic geometry of sub-frame is modeled in CAD software and transferred to ADAMS/CAR. Hence, the efficiency of the sub-frame in terms of reducing the induced vibration to vehicle cabin is examined through the various road inputs e.g. swept sine, step and random road input type (B). The results will illustrate that the sub-frame has significant effect in reduction of transmitted vibration to occupants. In order to optimize the sub-frame parameters, the sensitivity analysis is performed to derive effective parameters of sub-frame using DOE method. In this regard, the parameters which have dominant effect on transmitted vibration (the stiffness of sub-frame bushing in vertical direction) are optimized via RSM (Response Surface Method) method.
2014-04-01
Technical Paper
2014-01-1687
Sameer U. Kolte, David Neihguk, Abhinav Prasad, Samir Rawte, Aditya Gondhalekar
Abstract A typical powertrain mount design process starts with performing the system calculations to determine optimum mount parameters, viz. position, orientation and stiffness values to meet the desired NVH targets. Therefore, a 6 degrees of freedom lumped parameter system of powertrain and mounts is modelled in Matlab®. The approach is to decouple the torque roll axis mode from the remaining five rigid body modes so that the response to the torque pulses is predominantly ‘oscillations about Torque Roll Axis’. This is achieved by optimizing the above mount parameters within specified constraints so that ‘Rotation about the torque roll axis’ is one of the natural modes of vibration. The tool developed here uses ‘Particle Swarm Optimization(PSO) algorithm’ because of its ease of implementation and better convergence to the solution. The algorithm is programmed in TK solver®. Further, for the given torque input, the harmonic response of the powertrain mounted on optimized mounts, is evaluated for comparison with NVH targets.
2014-04-01
Technical Paper
2014-01-1690
Chien- Hsing Li, Yong-Yuan Ku, Ko Wei Lin
Abstract Due to the energy safety and environment protection, increase the percentage of biodiesel blend has become one of world wide strategies. In the past research, using biodiesel would affect the engine performance and increase the exhaust emission. Fortunately, these problems can be solved through the rapidly development of engine control technologies and lightweight structure design. However, the consideration of light/downsizing engine design with the same power has brought out much combustion noise. According to the higher and higher proportion has been widely used over the world. There was less researches focus on the different blending biodiesel impact on combustion noise. The combustion noise correspond to different blending biodiesel (D100,B5,B8,B20,B40,B100) which made form waste cooking oil has been discussion in this study. The experimental by using engine which meet EURO-4 was designed to caught spectrum of the combustion noise via transient window which under the constant engine speed of 1500rpm, 2000rpm, 2500rpm, with different torque at 30%, 50% and 70% of each speed, respectively.
2014-04-01
Technical Paper
2014-01-1758
Zamir Zulkefli, Maurice Adams
Abstract Gears are used in numerous applications where mechanical power needs to be transmitted as in the powertrain of cars, buses and other vehicles. These gears can potentially be a significant source of high-frequency vibration and radiated noise in a vehicle, which can be both harmful and objectionable to any listeners in the vicinity. A proposed approach to addressing the gear mesh-frequency vibrations is to utilize the low pass filtering effect of a hydrostatic bearing in a gear mesh-frequency noise mitigation system. This paper describes an experimental investigation of the low pass filtering effect of a hydrostatic bearing using an experimental setup involving a widely available materials testing machine. By using the materials testing machine, appropriately sized hydrostatic bearing and externally pressurized fluid supply system, empirical data was collected that allowed the frequency response of the hydrostatic bearing to be determined. The frequency response of the hydrostatic bearing clearly shows a low pass filtering effect on the applied dynamic loads.
2014-04-01
Technical Paper
2014-01-1757
Marco Mammetti, Marina Roche Arroyos
Abstract Over recent years IDIADA has developed several prototype electric vehicles as well as testing a number of electric powertrain configurations. Generally the electric motor output shaft delivers the torque to the transmission under a considerable level of high-frequency load variation and with noticeable torque irregularities that must be smoothed out in order to fulfill general NVH targets. This paper deals with the development phase of a prototype vehicle in which a specific testing activity was carried out to improve the overall NVH behavior of the powertrain. For this purpose, the mechanism of energy transference from the current to the motor and from the motor to the downstream driveline components was deeply characterized. The activity was aimed at smoothing the abrupt change in torque delivery and limiting the transfer of torque irregularities from the motor to the transmission. The torque control software calibration and the driveline elements were developed in order to reduce the noise and vibration critical frequency ranges.
2014-04-01
Technical Paper
2014-01-1756
Miguel De la Cruz, Stephanos Theodossiades
Abstract In this paper, a direct correlation between transmission gear rattle experiments and numerical models is presented, particularly focusing on the noise levels (dB) measured from a single gear pair test rig. The rig is placed in a semi-anechoic chamber environment to aid the noise measurements and instrumented with laser vibrometers, accelerometers and free field microphones. The input torsional velocity is provided by an electric motor, which is controlled by a signal generator, aiming to introduce an alternating component onto the otherwise nominal speed; thus, emulating the engine orders found in an internal combustion engine. These harmonic irregularities are conceived to be the triggering factor for gear rattle to occur. Hence, the rig is capable of running under rattling and non-rattling conditions. The numerical model used accounts for the gear pair's torsional dynamics, lubricated impacts between meshing teeth and bearing friction. The results show that rattle is indeed triggered by the governing engine orders present in the transmission's primary input shaft.
2014-04-01
Technical Paper
2014-01-1874
Tae-il Yoo, Hanhee Park, Gubae Kang, Seongyeop Lim
Abstract Development of eco-friendly vehicles have risen in importance due to fossil fuel depletion and the strengthened globalized emission control regulatory requirements. A lot of automotive companies have already developed and launched various types of eco-friendly vehicles which include hybrid vehicles (HEVs) or electric vehicles (EVs) to reduce fuel consumption. To maximize fuel economy Hyundai-Kia Motor Company has introduced eco-friendly vehicles which have downsized or eliminated vibration damping components such as a torque converter. Comparing with Internal Combustion Engine(ICE) powered vehicles, one issue of the electric motor propulsion system with minimized vibration damping components is NVH (Noise, Vibration and Harshness). The NVH problem is caused by output torque fluctuation of the motor system, resulting in the degradation of ride comfort and drivability. Therefore, accomplishing both fuel economy and good NVH performance has become a significantly challenging task in eco-friendly vehicles.
2014-04-01
Technical Paper
2014-01-1680
Sandeep Mahadev Jadhav
Abstract Objective of this research is to reduce gear rattle and whine noise. Study includes measurement of noise, vibration on transmission for source identification in order to eliminate rattle, whine through optimization of gear design and clutch damper performance. In order to optimize, we measured transmission torsional vibration and analyzed for proper selection of clutch dampers to reduce engine vibration transfer function to transmission. Through Noise & Vibration FFT, order and color map analysis we identified noise sources and further scope for specific gears design improvement. Hence test methodology adopted for development of gears and clutch damper successfully eliminated noise.
2014-04-01
Technical Paper
2014-01-1681
Manivasagam Shanmugam, Raghavendra Kharatmal, Shirish Satpute
Abstract This paper describes the rapid design and development of thin walled powertrain components which act as external cover for engine subsystem assemblies. Computer Aided Engineering plays a major role in reducing the overall product development lead time. An approach by using ‘Simulation Driven Design and Development’ helps the developers to bring the necessary confidence about the components' required functionality during the design stage itself. During the design stage, typical inputs available for the development of these components are the broad dimensions obtained from the packaging considerations. The designer is required to develop the concepts targeting least noise radiation from component surfaces due to various excitations. Based on cost considerations, the designer can even opt for plastic materials instead of steel. The current paper considers two major noise radiation members namely valve cover and timing gear cover for rapid product development. A conventional modal analysis followed by harmonic response studies provides the basis for the iterations towards designing these members.
2014-04-01
Technical Paper
2014-01-1679
S. Christopher Zugo, Craig D. Smith, Charles W. Braun, Joseph Kazour
Abstract The audible noise characteristics of direct injectors are important to OEM customers when selecting a high pressure gasoline fuel injector. The activation noise is an undesirable aspect that needs to be minimized through injector design, injector mounting, and acoustic treatments. Experimentally identifying the location and frequency of noise sources is beneficial to the improvement of injector designs. Acoustic holography is a useful tool in locating these noise sources by measuring a sound pressure field with multiple microphones and using this field to estimate the source location. For injector testing, the local boundary conditions of the noise source will affect the resultant sound field. Therefore, how the injector is mounted within the test fixture will change the resultant noise field measured. In this study, the process of qualifying an acoustic holography fixture using measurement system analysis for GDi fuel injector testing will be documented. The noise levels and source locations for different injector mounting conditions will be evaluated.
2014-04-01
Technical Paper
2014-01-1974
Gaurav Gupta, Rituraj Gautam, Chetan Prakash Jain
Abstract Interior sound quality is one of the significant factors contributing to the comfort level of the occupants of a passenger car. One of the major reasons for the deterioration of interior sound quality is the booming noise. Booming noise is a low frequency (20Hz∼300Hz) structure borne noise which occurs mainly due to the powertrain excitations or road excitations. Several methods have been developed over time to identify and troubleshoot the causes of booming noise [1]. In this paper an attempt has been made to understand the booming noise by analyzing structural (panels) and acoustic (cavity) modes. Both the structural modes and the acoustic modes of the vehicle cabin were measured experimentally on a B-segment hatchback vehicle using a novel approach and the coupled modes were identified. Panels contributing to booming noise were identified and countermeasures were taken to modify these panels to achieve decoupling of structural and cavity modes which results in the reduction of cabin noise levels.
2014-04-01
Technical Paper
2014-01-1364
Ornella Chiavola, Giancarlo Chiatti, Erasmo Recco
Abstract Many studies have demonstrated that an efficient control of the combustion process is crucial in order to comply with increasingly emerging Diesel emission standards and demanding for reduced fuel consumption. Methodologies based on real-time techniques are imperative and even if newly sensors will be available in the near future for on-board installation inside the cylinder, non intrusive measurements are still considered very attractive. This paper presents an experimental activity devoted to analyze the noise emission from a small displacement two-cylinder Diesel engine equipped by HPCR (high pressure common rail) fuel injection system. The signals acquired during stationary operation of the engine are analyzed and processed in order to highlight the different sources contributing to the overall emission. Particular attention is devoted to the specific samples of the signal that are mainly caused by the combustion process in order to extract the combustion contribution. The relationship between such a noise contribution and the in-cylinder pressure development during the combustion process is analyzed with the final aim of developing an algorithm in which the engine acoustic emission is used to compute key parameters able to fully characterize the pattern of the pressure development during the combustion process.
2014-04-01
Technical Paper
2014-01-0025
Kambiz Jahani, Sajjad Beigmoradi, Mohsen Bayani Khaknejad
Abstract The main objective of this study is to investigate the effect of spot-weld modeling approaches on NVH virtual simulation problems. For this purpose, finite element method is considered for further simulations. The goal is to evaluate and compare results within the domain of 0 to 200 Hz by modeling spot-welds with three different element types: a rigid body constraint element (RBE), two rigid body elements with hexahedral solid element (RBE3-HEXA-RBE3) and CWELD constraint. In order to evaluate the effects, three main NVH analyses are chosen for this study. In the first place, a free-free modal analysis is performed for the BIW and trimmed body models of a D-segment saloon car in order to estimate natural frequencies and mode shapes. Afterwards, a frequency response analysis is performed to evaluate the dynamic stiffness of engine mount. Finally, a noise transfer function (NTF) simulation is carried out to calculate the sound pressure level at driver ear's location. The out coming results from each type of simulations are extracted and compared to investigate the effect of spot-weld modeling on the accuracy of FEM analyses results concerning NVH problems.
2014-04-01
Technical Paper
2014-01-0038
Jin-Seok Hong, Hyung-Seok Kook, Kang-Duck Ih, Hyoung-Gun Kim
Abstract Fluctuation in the sound pressure level of the interior noise of an on-road vehicle is always caused by unpredictable factors such as wind gusts, traffic, roadside obstacles, and changing drive-by-drive conditions, and is hence, not reproducible in nature. Since the human brain is known to be more sensitive to noise that is amplitude-modulated than noise at a steady level [1], it is important to evaluate and improve the NVH performance of a vehicle in terms of the fluctuating interior noise likely to be experienced by drivers or users. To this end, an evaluation system was developed as part of this study, the details of which are presented in this paper. The system is composed of hardware for database storage and replay of sounds, and software for synthesizing the noise signals. For given wind tunnel test results, the evaluation system yields a wind noise model that can synthesize wind noise signals for any wind scenario. Additionally, the road and engine noise components can be extracted from proving ground or real road tests.
2014-04-01
Technical Paper
2014-01-0031
Takahito Watanabe, Takuya Yoshimura
Abstract In performing noise control design for vehicles, there is a benefit to identifying important vibro-acoustic coupled mode. The purpose of this study is “identifying the coupled mode of a vehicle through FRF (frequency response function) measurement”. A speaker which measure the internal acoustic pressure was used as a new experimental method. An acoustic input is estimated by the fluctuation of the acoustic pressure inside the speaker box. Acoustic pressures are measured by using some microphones, the vibrations of the structure are measured by using some accelerometers. Main experiment was carried out for measure the vibro-acoustic mode. First acoustic mode was identified in about 66 Hz. And structure associated mode with this mode was identified. Hence, the vibro-acoustic mode identification was carried out.
2014-04-01
Technical Paper
2014-01-0003
Manchi Venkateswara Rao, Jos Frank, Prasath Raghavendran
Abstract Accurate quantification of structure borne noise is a challenging task for NVH engineers. The structural excitation sources of vibration and noise such as powertrain and suspension are connected to the passenger compartment by means of elastomer mounts and spring elements. The indirect force estimation methods such as complex dynamic stiffness method and matrix inversion method are being used to overcome the limitations of direct measurement. In many practical applications, the data pertaining to load dependent dynamic stiffness of the connections especially related to mounts is not available throughout the frequency range of interest which limits the application of complex dynamic stiffness method. The matrix inversion method mainly suffers from the drawback that it needs operational data not contaminated by the effect of other forces which are not considered for calculation. In this paper, a new method is proposed in which the structure borne noise associated with powertrain is quantified easily and reliably.
2014-04-01
Technical Paper
2014-01-0015
Mohit Kohli, S Nataraja Moorthy, Manchi Venkateswara Rao, Prasath Raghavendran
Abstract The present quiet and comfortable automobiles are the result of years of research carried out by NVH engineers across the world. Extensive studies helped engineers to attenuate the noise generated by major sources such as engine, transmission, driveline and road excitations to a considerable extent, which made other noise sources such as intake, exhaust and tire perceivable inside. Many active and passive methods are available to reduce the effect of said noise sources, but enough care needs to be taken at the design level itself to eliminate the effect of cavity resonances. Experimental investigation of cavity resonances of real systems is necessary besides the FEA model based calculations. Acoustic cavity resonance of vehicle sub systems show their presence in the interior noise through structure borne and air borne excitations. Cavity resonances for some systems e.g. intake can only be suppressed through resonators. The exact location and nature of acoustic cavity resonance needs to be found as accurately as possible to bring out the best from a resonator.
2014-04-01
Technical Paper
2014-01-0462
Se Jin Park, Seung Nam Min, Murali Subramaniyam, Heeran Lee, Dong Gyun Kim, Cheol Pyo Hong
Abstract Vibration is both a source of discomfort and a possible risk to human health. There have been numerous studies and knowledge exists regarding the vibrational behavior of vehicle seats on adult human occupants. Children are more and more becoming regular passengers in the vehicle. However, very little knowledge available regarding the vibrational behavior of child safety seats for children. Therefore, the objective of this study was to measure the vibrations in three different baby car seats and to compare these to the vibrations at the interface between the driver and the automobile seat. The test was performed on the National road at the average speed of 70 km/h and acceleration levels were recorded for about 350 Sec (5.83 min). One male driver considered as an adult occupant and a dummy having a mass of 9 kg was representing one year old baby. Four accelerometers were used to measure the vibration. All measured accelerations were relative to the vertical direction. Vibration Analysis Toolset (VATS) was used for time domain analysis.
2014-04-01
Technical Paper
2014-01-0619
L.A.Raghu Mutnuri, Sivapalan Senthooran, Robert Powell, Zen Sugiyama, David Freed
Abstract A computational approach to evaluate rear-view mirror performance on wind noise in cars is presented in this paper. As a comfort metric at high speeds, wind noise needs to be addressed, for it dominates interior noise at mid-high frequencies. The impetus on rear-view mirror design arises from its crucial role in the flow field and the resulting pressure fluctuations on the greenhouse panels. The motivation to adopt a computational approach arises from the need to evaluate mirror designs early in vehicle design process and thus in conjunction with different vehicle shapes. The current study uses a Lattice Boltzmann method (LBM) based computational fluid dynamics(CFD) solver to predict the transient flow field and a statistical energy analysis(SEA) solver to predict interior noise contribution from the greenhouse panels. The accuracy of this computational procedure has been validated and published in the past. Realistic car geometry is chosen and the transient flow field around the vehicle resulting from mounting two different rear-view mirror designs is analyzed.
2014-04-01
Technical Paper
2014-01-0593
Hangsheng Hou
Abstract When a window opens to provide the occupant with fresh air flow while driving, wind throb problems may develop along with it. This work focuses on an analytical approach to address the wind throb issue for passenger vehicles when a front window or sunroof is open. The first case of this paper pertains to the front window throb issue for the current Ford Escape. Early in a program stage, CAA (Computational Aeroacoustics) analysis predicted that the wind throb level exceeded the program wind throb target. When a prototype vehicle became available, the wind tunnel test confirmed the much earlier analytical result. In an attempt to resolve this issue, the efforts focused on a design proposal to implement a wind spoiler on the side mirror sail, with the spoiler dimension only 6 millimeters in height. This work showed that the full vehicle CAA analysis could capture the impact of this tiny geometry variation on the wind throb level inside the vehicle cabin. The independent wind tunnel effort came to the same conclusion, and the difference between the analysis and testing is only about 1 dB.
2014-04-01
Technical Paper
2014-01-0822
Jong Ho Lee
Abstract Since vehicle NVH reduction technology has improved dramatically, buzz, squeak and rattle (hereafter referred to as “BSR”) noise quantification from interior and exterior of the vehicle becomes an important factor to measure the quality of the vehicle. (The cost rate of BSR noise claims take around 10-15%, moreover BSR noise negatively affects customers to purchase vehicles.) Therefore, a research of BSR evaluation comes to the fore to make a premium car. In this paper, we would like to introduce the development of a vehicle excitation test mode, the full-vehicle BSR test system, and a sound acoustic camera to detect BSR noise. The test profiles were correlated with various road severities such as the domestic field test sites including 5,000km cross-country off road, 19 test tracks for BSR in R&D test center, and quality test tracks in domestic factories. These test modes were classified into 4 levels (Low-Normal-High-Crazy) by judging degrees of GRMS values. The full-vehicle test system can reproduce various field road profiles of the BSR for chassis parts, interior, and exterior for temperatures of −40∼60°C.
2014-04-01
Technical Paper
2014-01-0923
Giovanni Morais Teixeira
Abstract Fatigue caused by forced vibration of a random nature is one of the major concerns in the automotive field. Random loading of components under actual driving conditions causes dynamic stress/strain responses which can be better described and handled in the frequency domain. Power Spectrum Density (PSD) is usually the most concise and straightforward way of representing a random process. Since frequency domain methodologies are gaining more respect and interest it is very important to be aware of their limitations and scope, particularly when compared to time domain algorithms. The present paper aims to discuss both approaches and establish some comparisons in terms of accuracy, range of application, computation time and user friendliness.
2014-04-01
Technical Paper
2014-01-1694
Michael Delbaere, Didier Frachon, Gerald Masson
Abstract Many synchronous electric motors require a very accurate position sensor compatible with a sinusoidal control. The purpose of such a control is to enable an efficient and smooth operation enhancing the comfort by limiting vibrations. In some cases related to mechanical constraints, we have to deal with through-shaft design. One can quote for examples power drives for Electric or Hybrid Electric Vehicles as well as for Electric Power Steering motor. More generally, these sensors need to keep a simple and robust design and a restricted number of parts as they are submitted to high vibration levels, a wide temperature range and speeds of several krpm. In order to meet such requirements, MMT has developed a magnetic sensor principle offering a competitive alternative to the conventional inductive resolver type sensors. The basics of this solution is a through shaft angular position sensor using one or two Hall-effect probes. These Hall IC measure the angle of the magnetic field generated by a ring or a disc magnet.
2014-04-01
Technical Paper
2014-01-1975
Manchi Venkateswara Rao, Jos Frank, Prasath Raghavendran
Abstract The customer demand for all wheel drive (AWD) vehicles is increasing over the period of time which also requires NVH performance on par with front wheel drive vehicles. AWD vehicles are equipped with power transfer unit, propeller shaft and independent rear differential assembly to achieve their functional requirement. The additional drive train components in AWD vehicles may amplify torsional fluctuations in the drive line. Hence achieving the NVH performance of AWD vehicles on par with FWD vehicles without any major change in the existing design is a major challenge. In this work, an AWD vehicle with severe body vibration and booming noise is studied. The operational measurements are taken throughout the drive train on all sub-systems from engine to the rear part of the body in the problematic operating condition. An operational deflection shape analysis is conducted to visualize the vibration behavior of the drive train. The result of analysis shows that the dynamic torsional fluctuations of the drive shaft and rear drive module (RDM) vibration are the major contributors for the high levels of vibration and noise.
2014-04-01
Technical Paper
2014-01-0893
Adarsh Venkata Padmanabhan, Hariram Ravichandran, Lokendra Pavan Kumar Pappala, Rangaraj Ramanan Durai
Abstract This paper will discuss information extraction from sound signals obtained using acoustic sensors which are strategically placed on the automotive body. The sound signal obtained contains useful information such as vehicle and road surface characteristics. The aforementioned information was spread out at different frequencies in the spectral distribution of the signal. Well defined filters for the corresponding frequency bands were used to isolate these characteristics and patterns pertaining to the identified useful information from the signal. The obtained information can be used as inputs for systems such as vehicle safety systems, power train systems and NVH (Noise, Vibration and Harshness) systems.
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