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Viewing 211 to 240 of 7819
2017-03-28
Technical Paper
2017-01-1136
Jack S.P. Liu, Natalie Remisoski, Javed Iqbal, Robert Egenolf
Automotive vehicles equipped with Cardan joints may experience low frequency vehicle launch shudder vibration (5-30Hz) and high frequency driveline moan vibration (80-200Hz) under working angles and speeds. The Cardan joint introduces a 2nd order driveshaft speed variation and a 4th order joint articulation torque (JAT) causing the vehicle shudder and moan NVH issues. Research on the Cardan joint induced low frequency vehicle shudder using a Multi-Body System (MBS) method has been attempted. A comprehensive MBS method to predict Cardan joint induced high frequency driveline moan vibration is yet to be developed. This paper presents a hybrid MBS and Finite Element Analysis (FEA) approach to predict Cardan joint induced high frequency driveshaft moan vibration. The CAE method considers the elastically coupled driveshaft bending and engine block vibration due to Cardan joint excitation.
2017-03-28
Technical Paper
2017-01-1023
Yaqun Jiang, C. Hsieh, Georg Festag, Masood Ahmed, William Jiang
Abstract Large axial displacement at the edge of a flywheel causes a clutch to fail to disengage in high-speed rotation. To find out the root cause, a numerical procedure is proposed to investigate the vibration source and to understand dynamic behavior of the crank-train system. A simulation of the whole engine system including block, crankshaft, piston, and connecting rod was performed with AVL/Excite. The resulting CAE baseline model had good correlation with measurements. A comprehensive study was conducted for a set of flywheel and crankshaft models with different materials and unbalanced masses. The contribution to flywheel wobbling of each vibration order was carefully investigated, and an optimal design was presented.
2017-03-28
Technical Paper
2017-01-1064
Mustafa Yıldırım
Abstract Engine design is crucial in terms of NVH. It is the sources of vibration for a vehicle. Nowadays engine tends to being smaller and less stiff and more powerful according to predecessor. Small engines with high power is inherently generates extreme force and vibrations and accordingly generates more noise. Thus engine structure and also engine main components should be designed to prevent this vibration. There are two main sources: One of them is combustion and other is inertia loads. Due to this sources engine structure can cause severe vibration and accordingly this can cause noise via transmitting it into vehicle with both structure and airborne. This paper focused on to reduce engine vibration level with changing the combustion inputs such as cylinder pressure parameters and inertia parameters like piston mass, conrod length and balancing parameters. Design of experiment is used to obtain most robust case in terms of NVH.
2017-03-28
Technical Paper
2017-01-1070
Da Shao, Xu Sichuan, Aimin Du
Abstract The electromagnetic valve actuator (EMVA) is considered a technological solution for decoupling between crankshaft and camshaft to improve engine performance, emissions, and fuel efficiency. Conventional EMVA consists of two electromagnets, an armature, and two springs has been proved to have the drawbacks of fixed lift, impact noise, complex control method and large power consumption. This paper proposes a new type of EMVA that uses voice coil motor (VCM) as electromagnetic valve actuator. This new camless valvetrain (VEMA) is characterized by simple structure, flexible controllable and low actuating power. VCM provides an almost flat force versus stroke curve that is very useful for high precision trajectory control to achieve soft landing within simple control algorithm.
2017-03-28
Technical Paper
2017-01-1231
Chun Tang, Natee Limsuwan, Nurani Chandrasekhar, Zhichun Ma, Jacob Krizan, Joel Hetrick, Wei Wu
Abstract The current of an electric machine driven by PWM switching inverter is not ideal sinusoidal, containing different levels of harmonics. The current harmonics have important impact on the electrical machine torque ripple which could translate into transmission and vehicle level Noise Vibration and Harshness (NVH). In this work, the current waveforms were measured from dyno test at prescribed torque and speed levels, and the electric machine torque ripple was computed with the measured current. This paper will focus on the investigation of the current harmonics behaviors and features at various torque and speed conditions, the impact on torque ripple, and the possible mitigation method to reduce torque ripple.
2017-03-28
Journal Article
2017-01-1465
William R. Bussone, Joseph Olberding, Michael Prange
Abstract SAE J211 provides no definitive specification as to the appropriate procedures for filtering angular rate sensor data prior to differentiation into angular acceleration data, especially for impact data. Accordingly, a 3-2-2-2 array (nine-accelerometer-package or NAP) of linear accelerometers and a triaxial angular rate sensor were mounted into a Hybrid III 50th-percentile-male ATD headform and compared in a variety of impact events and multibody simulations. Appropriate low-pass digital filter cutoff frequencies for differentiating the angular rate sensor data into angular accelerations were sought via residual analysis in accordance with current SAE J211 guidelines.
2017-03-28
Journal Article
2017-01-0441
Zhenyu Wang, Mei Zhuang
Abstract A numerical study on sunroof noise reduction is carried out. One of the strategies to suppress the noise is to break down the strong vortices impinging upon the trailing edge of the sunroof into smaller eddies. In the current study, a serrated sunroof trailing edge with sinusoidal profiles of wavelengths is investigated for the buffeting noise reduction. A number of combinations of wavelengths and amplitudes of sinusoidal profiles is employed to examine the effects of trailing edge serrations on the noise reduction. A generic vehicle model is used in the study and a straight trailing edge is considered as a baseline. The results indicate that the trailing edge serration has a significant impact on the sound pressure level (SPL) in the vehicle cabin and it can reduce the SPL by up to 10~15 dB for the buffeting frequency.
2017-03-28
Journal Article
2017-01-1053
Satoshi Watanabe, Yuji Miyata, Yosuke Ogata, Vincent Ivosic
Abstract Idling stop systems are being increasingly adopted in conventional engine vehicles as well as hybrid electric vehicles to increase fuel efficiency. When the engine starts, body vibration occurs that is caused by the rigid body eigenvalues of the power plant during initial combustion. Engine restart vibration after an idling stop is caused by the input force from the transmission, and the reaction force from the drive shaft as well as the input force from the engine. This phenomenon occurs frequently when the engine is restarted from the idling stop, the vibration is increasingly annoying to passengers. Usually, the vehicle development process is carried out in accordance with the V process. The V process divides the vehicle development process into two stages. The first stage is called the vehicle design stage to determine the characteristic. The second stage is called the vehicle verification stage to verify the performance.
2017-03-28
Journal Article
2017-01-0444
Weiguo Zhang, Mark Likich, Brian Butler, John White
Abstract Engine air induction shell noise is a structure borne noise that radiates from the surface of the air induction system. The noise is driven by pulsating engine induction air and is perceived as annoying by vehicle passengers. The problem is aggravated by the vehicle design demands for low weight components packaged in an increasingly tight under hood environment. Shell noise problems are often not discovered until production intent parts are available and tested on the vehicle. Part changes are often necessary which threatens program timing. Shell noise should be analyzed in the air induction system design phase and a good shell noise analytical process and targets must be defined. Several air induction clean side ducts are selected for this study. The ducts shell noise is assessed in terms of material strength and structural stiffness. A measurement process is developed to evaluate shell noise of the air induction components.
2017-03-28
Journal Article
2017-01-1120
Kenji Tsutsumi, Yoshitaka Miura, Yusuke Kageyama, Arata Miyauchi
Abstract A CVT variator chain system is superior in transmission efficiency to a belt system because of its lower internal friction. However, a chain produces more noise than a belt due to the long pitch length of contact between the pulleys and rocker pins. This study focuses on optimization of the pitch sequence for reducing chain noise. The previous pitch sequence was suitably combined of links of different lengths to improve noise dispersibility for reducing chain noise. First, the object function was defined as the reduction of the peak level of 1st-order chain noise combined with a well-balanced the levels on the low and high frequency sides. Interior background noise consisting of road noise and wind noise have the characteristic that they increase as the frequency decreases.
2017-03-28
Journal Article
2017-01-1126
Yu Mao, Shuguang Zuo, Xudong Wu
Abstract Due to coupling of in-wheel motor and wheel/tire, the electric wheel system of in-wheel motor driven vehicle is different from tire suspension system of internal combustion engine vehicle both in the excitation source and structural dynamics. Therefore emerging dynamic issues of electric wheel arouse attention. Longitudinal vibration problem of electric wheel system in starting condition is studied in this paper. Vector control system of permanent magnet synchronous hub motor considering dead-time effect of the inverter is primarily built. Then coupled longitudinal-torsional vibration model of electric wheel system is established based on rigid ring model and dynamic tire/road interface. Inherent characteristics of this model are further analyzed. The vibration responses of electric wheel system are simulated by combining electromagnetic torque and the vibration model.
2017-03-28
Journal Article
2017-01-1507
Prashanta Gautam, Yousof Azizi, Abhilash Chandy
Abstract Tire noise is caused due to the complex interactions between the rotating tire and the road surface at the tire/road interface. It is usually caused due to a combination of individual noise generation mechanisms, which can either be structural or air-borne. The influence of each of these noise generation mechanism may vary, depending on various conditions such as tire design, road surface and operating conditions. Due to the many variables that affect the noise generation mechanisms in tires, it is usually a very complex task to isolate and categorize those that are present in the overall tire/road noise spectrum. Various approaches are used to categorize noise generation mechanisms in tires. In this paper, a statistical model based on the assumption that the tire noise acoustic pressure at a specific frequency band is related to the vehicle speed, is used, in order to study tire noise at different speeds.
2017-03-28
Technical Paper
2017-01-1130
Shinya Takamatsu, Nobuharu Imai, Koji Tsurumura, Seiji Yamashita, Hiroaki Tashiro
Abstract The renewed platform of the upcoming flagship front-engine, rear-wheel drive (FR) vehicles demands high levels of driving performance, fuel efficiency and noise-vibration performance. The newly developed driveline system must balance these conflicting performance attributes by adopting new technologies. This article focuses on several technologies that were needed in order to meet the demand for noise-vibration performance and fuel efficiency. For noise-vibration performance, this article will focus on propeller shaft low frequency noise (booming noise). This noise level is determined by the propeller shaft’s excitation force and the sensitivity of differential mounting system. In regards to the propeller shaft’s excitation force, the contribution of the axial excitation force was clarified. This excitation force was decreased by adopting a double offset joint (DOJ) as the propeller shaft’s second joint and low stiffness rubber couplings as the first and third joints.
2017-03-28
Journal Article
2017-01-1054
Imad M. Khan, Makrand Datar, Wulong Sun, Georg Festag, T Bin Juang, Natalie Remisoski
Abstract At various milestones during a vehicle’s development program, different CAE models are created to assess NVH error states of concern. Moreover, these CAE models may be developed in different commercial CAE software packages, each one with its own unique advantages and strengths. Fortunately, due to the wide spread acceptance that the Functional Mock-up Interface (FMI) standard gained in the CAE community over the past few years, many commercial CAE software now support cosimulation in one form or the other. Cosimulation allows performing multi-domain/multi-resolution simulations of the vehicle, thereby combining the advantages of various modeling techniques and software. In this paper, we explore cosimulation of full 3D vehicle model developed in MSC ADAMS with 1D driveline model developed in LMS AMESim. The target application of this work is investigation of vehicle NVH error states associated with both hybridized and non-hybridized powertrains.
2017-03-28
Technical Paper
2017-01-1145
Eric De Hesselle, Mark Grozde, Raymond Adamski, Thomas Rolewicz, Mark Erazo
Abstract Hybrid electric vehicles are continuously challenged to meet cross attribute performance while minimizing energy usage and component cost in a very competitive automotive market. As electrified vehicles become more mainstream in the marketplace, hybrid customers are expecting more attribute refinement in combination with the enhanced fuel economy benefits. Minimizing fuel consumption, which tends to drive hybrid powertrain engines to operate under lugging type calibrations, traditionally challenge noise, vibration, and harshness (NVH) metrics. Balancing the design space to satisfy the cost metrics, energy efficiency, noise and vibration & drivability under the hybrid engine lugging conditions can be optimized through the use of multiple CAE tools. This paper describes how achieving NVH metrics can put undesirable boundaries on Powertrain Operation which could affect other performance attributes.
2017-03-28
Technical Paper
2017-01-1487
Russ Norton, Ben Bulat, Ahmed Mohamed
Abstract A semi-active suspension system is designed to improve secondary ride by lowering damping levels while maintaining or enhancing primary ride control and vehicle handling. In order to provide optimized ride comfort, base damping levels are reduced. Reduced damping levels increase damaging loads through pothole events. The Road Load Mitigation (RLM) algorithm seeks to resolve the tradeoff of high damping levels required to control the vertical and horizontal spindle loads and the need for lower damping forces to improve secondary ride. As the base active damping forces are increased to control these loads, ride benefits or vehicle ride comfort is diminished. RLM looks at suspension velocity at all four corners independently to determine if a pothole signature is detected and requires compensation. Compensation is delivered quickly to reduce wheel drop into the pothole thereby reducing damaging loads.
2017-03-28
Journal Article
2017-01-0495
Michael Christian Haverkamp
Abstract The vehicle interior constitutes the multi-sensory environment of driver and passengers. Beside overall design and execution, materials and its surfaces are of specific interest to the customer. They are not only needed to fulfil technical functions, but are in direct focus of the customer’s perception. The perceived quality is based on all sensory data collected by the human perceptual system. Surfaces express design intent and craftsmanship by their visual appearance. Haptic features supervene when materials are touched. And even smell has an influence on the perception of ambience. Although sound is generated nearly every time when fingers slide across a surface, touch-sounds have been disregarded so far. In various cases, these contact sounds are clearly audible. As essential sound responses to haptic activity, they can degrade perceived quality. A method has been developed for a standardized generation of touch-sounds.
2017-03-28
Journal Article
2017-01-1634
Hui Sung Lee
Abstract When customers use a tailgate (or trunk), some systems such as power tailgate and smart tailgate have been introduced and implemented for improving convenience. However, they still have some problems in some use cases. Some people have to search for the outside button to open the tailgate, or they should take out the key and push a button. In some cases, they should move their leg or wait a few seconds which makes some people feel that it is a long time. In addition, they have to push the small button which is located on the inner trim in order to close the tailgate. This paper proposes a new tailgate control technology and systems based on acoustic patterns in order to solve some inconvenience. An acoustic user interaction (AUI) is a technology which responds to human’s rubbing and tapping on a specific part analyzing the acoustic patterns. The AUI has been recently spotlighted in the automotive industry as well as home appliances, mobile devices, musical instruments, etc.
2017-03-28
Journal Article
2017-01-1693
John Huber, Ranjani Rangarajan, An Ji, Francois Charette, Scott Amman, Joshua Wheeler, Brigitte Richardson
Abstract This paper describes a method to validate in-vehicle speech recognition by combining synthetically mixed speech and noise samples with batch speech recognition. Vehicle cabin noises are prerecorded along with the impulse response from the driver's mouth location to the cabin microphone location. These signals are combined with a catalog of speech utterances to generate a noisy speech corpus. Several factors were examined to measure their relative importance on speech recognition robustness. These include road surface and vehicle speed, climate control blower noise, and driver's seat position. A summary of the main effects from these experiments are provided with the most significant factors coming from climate control noise. Additionally, a Signal to Noise Ratio (SNR) experiment was conducted highlighting the inverse relationship with speech recognition performance.
2017-03-28
Technical Paper
2017-01-1229
Ken Yamamoto, Nobuyasu Sadakata, Hidetoshi Okada, Yusuke Fujita
Abstract Electric oil pumps (EOP) for automobiles are used to lubricate and cool moving parts and supply oil pressure to components. Conventional EOPs consist of two separate units including a motor driver and a pump system comprised of a motor and a pump, which impedes layout flexibility for vehicles. To overcome this shortcoming, we have developed an ECU (electronic control unit)-integrated oil pump in which a driver, a motor and a pump are incorporated as a single unit. In the course of the project, we focused on improving vibration resistance and developing a compact design. The first challenge was to improve vibration resistance because of the driver located in close proximity to the powertrain. Since the driver is installed on the motor unit via electrically welded bus bars, the joints of the driver and the bus bar become susceptible to vibration.
2017-03-28
Technical Paper
2017-01-1226
Nurani Chandrasekhar, Chun Tang, Natee Limsuwan, Joel Hetrick, Jacob Krizan, Zhichun Ma, Wei Wu
Abstract Noise and Vibration (NVH) characteristic of an electric machine (e-Machine) is the outcome of complex interaction between source level disturbances and the surrounding structure to which the e-Machine is attached. Key e-Machine metrics that objectively quantify source level disturbance include torque ripple and radial electro-magnetic forces. These disturbances can radiate directly from the e-Machine housing (air-borne component) and also can be transmitted through the structural attachments like stator bolts, stator ring, powertrain mounts etc. (structure-borne component). In the e-machine driven by PWM switching inverter, current is not perfectly sinusoidal but contain different level of harmonics. Current harmonics impact Torque ripple, which in turn would translate into undesirable noise and vibration. There is very limited literature referencing the influence of current harmonics on torque ripple and e-machine NVH.
2017-03-28
Journal Article
2017-01-0333
Kurt Munson, Frederic Kihm, Andrew Halfpenny
Abstract Finite Element Analysis (FEA)-based structural simulations are typically used to assess the durability of automotive components. Many parts experience vibration in use, and resonance effects are directly linked to many structural problems. In this case, dynamics must be included in the structural analysis. Dynamic FEA can be more realistic than static analysis, but it requires knowledge of additional characteristics such as mass and damping. Damping is an important property when performing dynamic FEA, whether transient or steady state dynamics, as it governs the magnitude of the dynamic stress response and hence durability. Unfortunately the importance of damping is often overlooked; sometimes a default damping value is erroneously assumed for all modes. Errors in damping lead to errors in the stress response, which in turn lead to significant changes in the fatigue life estimates.
2017-03-28
Journal Article
2017-01-1539
Vinh Long Phan, Hiroshi Tanaka, Takaaki Nagatani, Mikio Wakamatsu, Tsuyoshi Yasuki
Abstract High frequency wind noise caused by turbulent flow around the front pillars of a vehicle is an important factor for customer perception of ride comfort. In order to reduce undesirable interior wind noise during vehicle development process, a calculation and visualization method for exterior wind noise with an acceptable computational cost and adequate accuracy is required. In this paper an index for prediction of the strength of exterior wind noise, referred to as Exterior Noise Power (ENP), is developed based on an assumption that the acoustic power of exterior wind noise can be approximated by the far field acoustic power radiated from vehicle surface. Using the well-known Curle’s equation, ENP can be represented as a surface integral of an acoustic intensity distribution, referred to as Exterior Noise Power Distribution (ENPD). ENPD is estimated from turbulent surface pressure fluctuation and mean convective velocity in the vicinity of the vehicle surface.
2017-03-28
Journal Article
2017-01-0403
Guangqiang Wu, Huwei Wu
Abstract Experimental schemes, frequency characteristics, subjective and objective sound quality evaluation and sound quality prediction model establishment of a certain mass-production SUV (Sport Utility Vehicle, SUV) manual transmission gear rattle phenomenon were analyzed in this paper. Firstly, vehicle experiments, including experiment conditions, vibration acceleration sensor and microphone arrangements and especial considerations in experiments, were described in detail. Secondly, through time-frequency analysis, broadband characteristics of manual transmission gear rattle noise were identified and vibro-impact of gear rattle occurs in the frequency range of 450~4000Hz on the vehicle idle condition and the creeping condition. Thirdly, based on bandwidth filtering processing of gear rattle noise, subjective assessment experiments by a paired comparison method were carried out.
2017-03-28
Journal Article
2017-01-0420
Prashant Khapane, Sumiran Lohani
Abstract Vibration Isolation is the key objective of engine mounting systems in the automotive industry. A well-designed, robust engine mount must be capable of isolating the engine assembly from road-based excitations. Owing to high vibration inputs, engine mounts are susceptible to wear and failure. Thus, the durability of engine mounts is a cause for concern. A design validation methodology has been developed at Jaguar Land Rover using Multibody Dynamics (MBD) to enhance the prognosis of engine mount loads during full - vehicle durability test events. This paper describes the development of a virtual multi-axial simulation table rig (MAST Rig) to test virtual engine mount designs. For the particular example considered in this paper, a simple sinusoidal input is applied to the MAST Rig. The development of the virtual MAST Rig has been described including details of the modelling methodology.
2017-03-28
Journal Article
2017-01-1330
Youssef Ziada, Juhchin Yang, David DeGroat-Ives
Abstract Owing to decreased development cycle timing, designing components for manufacturability has never been as important. Assessing manufacturing feasibility has therefore become an increasingly important part of new product engineering. This manufacturing feasibility is conventionally assessed based on static stiffness of components and fixture assemblies. However, in many operations, excess vibration represents the actual limitation on processing a workpiece. Limits on how far into components a tool can reach or the amount of processing time required to machine a feature is commonly decreased significantly due to vibration. Critical time is spent resolving these vibration problems during product launches. Depending on the machining configurations these vibrations can be due to the part & work support structure or due to the tooling & spindle assembly.
2017-03-28
Journal Article
2017-01-1325
U Oh, Kazuya Kusano, Norihiko Nonaka, Hironobu Yamakawa
Abstract Automotive fuel can be efficiently combusted by injecting it into the cylinders at high pressure to atomize it to pass the regulations for exhaust gas and fuel economy. For this reason, automotive companies have developed direct injection engines, which can inject gasoline into the cylinders directly. Furthermore, the demand for lower-noise high pressure pumps is also increasing from the viewpoint of automotive comfort. Since the valve velocity and noise level will increase as the pressure in fuel pumps increases, noise problems need to be solved under the high pressure conditions. Accordingly, the valve motion should be predicted with high accuracy under operating conditions to evaluate the noise caused by valve impingement. In addition, the squeeze film effect phenomenon will occur in the physical fuel pumps affect the prediction of the noise level caused by valve impingement.
2017-03-14
Journal Article
2017-01-9277
Stefano D'Ambrosio, Alessandro Ferrari
Abstract The present paper illustrates an investigation about the potentialities of injection rate shaping coupled with an after injection. A pilot shot can either be absent or present before the rate-shaped boot injection. The experimental tests have been performed on a partial PCCI Euro 5 diesel engine endowed with direct-acting piezoelectric injectors. Starting from optimized triple pilot-main-after injection strategies, boot injection was implemented by maintaining the direct-acting piezo injector needle open at part lift. The results of two steady state working conditions have been presented in terms of engine-out emissions, combustion noise and brake specific fuel consumption. In addition, in-cylinder analyses of the pressure, heat-release rate, temperature and emissions have been evaluated. Considering the in-cylinder pressure traces and the heat release rate curves, the injection rate shaping proved to influence combustion in the absence of a pilot injection to a great extent.
2017-03-14
Journal Article
2017-01-9677
Chengwu Duan, Jian Yao, Ying Huang
Abstract A toothed chain continuously variable transmission concept is studied. By designing positive engagement at top overdrive ratio, we explored the potential to improve CVT mechanical efficiency. The low cost solution could improve fuel economy by 0.7% in FTP composite cycle. Preliminary multi-body dynamic simulation is also completed using VL-Motion to concept-proof the technical feasibility of disengagement and engagement. To address the noise issue resulted from abandoning the random pitch design in production chain, we proposed an alternate chain pitch sequence but more experimental data is required to validate the design.
2017-01-10
Technical Paper
2017-26-0270
Rahul Gurav, Kishor D Udawant, Ramkumar Rajamanickam, N V Karanth, S R Marathe
Abstract With emission norms getting more and more stringent, the trend is shifting towards electric and hybrid vehicles. Electric motor replaces engine as the prime mover in these vehicles. Though these vehicles are quieter compared to their engine counterpart, they exhibit certain annoying sound quality perception. There is no standard methodology to predict the noise levels of these motors. Electric motor noise comprises of mainly three sources viz., Aerodynamic, Electromagnetic and Mechanical. A methodology has been developed to predict two major noise sources of electric motor out of the three above viz. Mechanical and Aerodynamic noise. These two noise sources are responsible for the tonal noise in an electric motor. Aerodynamic noise arises most often around the fan, or in the vicinity of the machine that behaves like a fan. This noise is predominant at higher motor speed and also in electric vehicle due to higher speed fluctuation.
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