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2015-06-15
Journal Article
2015-01-2182
Yawen Wang, Junyi Yang, Xuan Li, Guohua Sun, Teik Lim
Abstract Due to the design of lightweight, high speed driveline system, the coupled bending and torsional vibration and rotordynamics must be considered to predict vibratory responses more realistically. In the current analysis, a lumped parameter model of the propeller shaft is developed with Timoshenko beam elements, which includes the effect of rotary inertia and shear deformation. The propeller shaft model is then coupled with a hypoid gear pair representation using the component mode synthesis approach. In the proposed formulation, the gyroscopic effect of both the gear and propeller shaft is considered. The simulation results show that the interaction between gear gyroscopic effect and propeller shaft bending flexibility has considerable influence on the gear dynamic mesh responses around bending resonances, whereas the torsional modes still dominate in the overall frequency spectrum.
2015-06-15
Journal Article
2015-01-2179
Laihang Li, Rajendra Singh
Abstract The transient vibration phenomenon in a vehicle powertrain system during the start-up (or shut-down) process is studied with focus on the development and experimental validation of the nonlinear powertrain models. First, a new nonlinear four-degree-of-freedom torsional powertrain model for this transient event, under instantaneous flywheel motion input, is developed and then validated with a vehicle start-up experiment. Second, the interactions between the clutch damper and the transmission transients are established via transient metrics. Third, a single-degree-of-freedom nonlinear model, focusing on the multi-staged clutch damper, is developed and its utility is then verified.
2015-06-15
Journal Article
2015-01-2216
Dong Chul Park, Eun Soo Jo, Seokgwan Hong, Michael Csakan
Abstract An important trend among vehicle NVH engineers is the production of attractive engine acceleration sound quality for the enhancement of a vehicle's image and performance. In addition, customers have increasing interest and enjoyment in customizing their cars to reflect their personal taste and preferences. The PESS (Personalized Engine Sound System) has been developed for making a unique and individually customizable vehicle concept. The system allows the customers an opportunity to create a variety of engine sounds in a single vehicle using active sound design technology. In this system, three different engine sound concepts are pre-defined, Dynamic, Sporty, and Extreme. Each of the engine sounds can then be adjusted with parameters that determine the timbre, such as main order, rumble, and high order. In addition, the pedal position during acceleration has also been used as a parameter to further personalize the experience.
2015-06-15
Journal Article
2015-01-2218
Shuguang Zuo, Jun Zhang, Xudong Wu, Jiajie Hu, Guo Long
Abstract Blower is one of the main noise sources of fuel cell vehicle. In this paper, a narrowband active noise control (ANC) model is established based on adaptive notch filter (ANF) to control the high-frequency noise produced by the blower. Under transient conditions, in order to reduce the frequency mismatch (FM) of ANC for blower, a new Frequency Mismatch Filtered-Error Least Mean Square algorithm (FM-FELMS) is proposed to attenuate blower noise under transient conditions. According to the theoretical analysis and simulation, the proposed algorithm has an excellent noise reduction performance at relatively high blower speed. While for the low speed working condition, the Normalized Least Mean Square (NLMS) algorithm is applied to attenuate noise. The two algorithms could be jointly utilized to control the blower noise actively.
2015-06-15
Journal Article
2015-01-2223
Rolf Schirmacher
Abstract Active Noise Control (ANC) has long been seen as emerging technology. During recent years, however, it became popular in new vehicle and infotainment platforms within a broad range of OEMs. This paper summarizes the current status and lessons learned of production systems (as well as those entering production soon) and gives an outlook on how ANC and related technologies will integrate in future vehicles and audio/infotainment architectures.
2015-06-15
Journal Article
2015-01-2222
Nikos Zafeiropoulos, Marco Ballatore, Andy Moorhouse, Andy Mackay
Road noise forces can excite different structural resonances of the vehicle hence a high number of sensors required for observing and separating all the vibrations that are coherent with the cabin noise. Current reference sensor selection methods for feedforward road noise control result to high number of sensors. Therefore there is a necessity for reducing the number of sensors without degrading the performance of an ANC system. In the past coherence function analysis has been found to be useful for optimising the sensor location. Thus, in this case coherence function mapping was performed between an array of vibration sensors and a microphone in order to identify the locations on the structure with highly correlated with road bands in the compartment. A vehicle with an advanced suspension system was used for applying the method and defining some locations as reference signals for feedforward active road noise control.
2015-06-15
Journal Article
2015-01-2193
Masami Matsubara, Daiki Tajiri, Makoto Horiuchi, Shozo Kawamura
Abstract One of the elements of tire stiffness is sidewall stiffness. This stiffness, which influences tire vibration characteristics, is also an important design parameter for carrying the vehicle body. Tire is one of pressure vessels and inflation pressure is dominant in sidewall stiffness. Thus, tire sidewall stiffness is decided from the tension of inflation pressure and the structural dynamic, including the properties of the rubber material. To reveal the dynamic characteristics of tire sidewall stiffness, this study describes differences in stiffness due to inflation pressure. It can be expected that variation of inflation pressure is monitored from the axle vibration response during vehicle traveling in the future. That is because the relationship of the vibration characteristics and the inflation pressure of tire are derived by sidewall stiffness. First, we derive a formula for sidewall stiffness based on the structural dynamics of Akasaka's theory.
2015-06-15
Journal Article
2015-01-2188
Zhaohui Sun, Glen Steyer, Chih Hung Chung, Gregory Kopp
Abstract This paper discusses approaches to properly design aluminum axles for optimized NVH characteristics. By effectively using well established and validated FEA and other CAE tools, key factors that are particularly associated with aluminum axles are analyzed and discussed. These key factors include carrier geometry optimization, bearing optimization, gear design and development, and driveline system dynamics design and integration. Examples are provided to illustrate the level of contribution from each main factor as well as their design space and limitations. Results show that an aluminum axle can be properly engineered to achieve robust NVH performances in terms of operating temperature and axle loads.
2015-06-15
Journal Article
2015-01-2199
Rui Cao, J Stuart Bolton
Abstract Experimental measurements of tire tread band vibration have provided direct evidence that higher order structural-acoustic modes exist in tires, not just the well-known fundamental acoustical mode. These modes display both circumferential and radial pressure variations within the tire's air cavity. The theory governing these modes has thus been investigated. A brief recapitulation of the previously-presented coupled structural-acoustical model based on a tensioned string approach will be given, and then an improved tire-acoustical model with a ring-like shape will be introduced. In the latter model, the effects of flexural and circumferential stiffness are considered. This improved model accounts for propagating in-plane vibration in addition to the essentially structure-borne flexural wave and the essentially airborne longitudinal wave accounted for in the previous model. The longitudinal structure-borne wave “cuts on” at the tire's circumferential ring frequency.
2015-06-15
Journal Article
2015-01-2325
P. Bremner, C. Todter, S. Clifton
Title: Sideglass Turbulence and Wind Noise Sources Measured with a High Resolution Surface Pressure Array Authors: Paul Bremner – AeroHydroPLUS, Del Mar CA 92104 USA Chris Todter – Keppel Professional Services, San Diego CA 92107 Scott Clifton – c/o AeroHydroPLUS, Del Mar CA 92104 USA The authors report on the design and use of high resolution micro-electro-mechanical (MEMS) microphone arrays for automotive wind noise engineering. The arrays integrate both sensors and random access memory (RAM) chips on a flexible circuit board that eliminates high channel count wiring and allows the array to be deployed on automobile surfaces in a convenient “stick-on/peel-off” configuration. These arrays have application to the quantitative evaluation of interior wind noise from measurements on a clay model in the wind tunnel, when used in conjunction with a body vibro-acoustic model.
2015-06-15
Journal Article
2015-01-2357
Hiromichi Tsuji, Kimihiko Nakano
In the early stage of digital phase and prototype experimental phase, the identification of the operational force on the components and the most important paths of the vibration correlated to the one of the evaluation points, such as steering, seats, and passenger ears, is required for optimizing the dynamic characteristics of the subsystem components of the vehicle. The transfer path analysis (TPA) with the impedance matrix of the component joints is widely used and reliable method to identify the force and the paths of the noise and vibration. However, the conduction of this TPA costs a lot of times. In addition, the estimated force includes not contributing to the evaluation responses. The uncorrelated force to the evaluation responses causes the design errors of the dynamic characteristics in the digital development phase. To solve the problems, a new force estimation technique is presented in this paper.
2015-06-15
Journal Article
2015-01-2335
Scott Amman, Francois Charette, Paul Nicastri, John Huber, Brigitte Richardson, Gint Puskorius, Yuksel Gur, Anthony Cooprider
Quantifying Hands-free Call Quality in an Automobile Hands-free phone use is the most utilized use case for vehicles equipped with infotainment systems with external microphones that support connection to phones and implement speech recognition. Critically then, achieving hands-free phone call quality in a vehicle is problematic due to the extremely noisy nature of the vehicle environment. Noise generated by wind, mechanical and structural, tire to road, passengers, engine/exhaust, HVAC air pressure and flow are all significant contributors and sources of noise. Other factors influencing the quality of the phone call include microphone placement, cabin acoustics, seat position of the talker, noise reduction of the hands-free system, etc. This paper describes the work done to develop procedures and metrics to quantify the effects that influence the hands-free phone call quality.
2015-06-15
Journal Article
2015-01-2252
Haixin Dai, Weikang Jiang, Yuanyi Huang
Engine mounting plays an important role to interior noise of automobiles. Decoupling optimal design of mounting has been researched for long, but vibration power into body transmitted from engine can be a more intuitive way to improve NVH performance. Some approach for minimizing transfer power through engine mount based on finite element model was reported, whose disadvantages are lack of data and inaccuracy at high frequency in some cases. To get an analytic formula of transmitted power, a model considering coupled vibration between bodywork and engine is presented here. In this model, the engine is modeled as a rigid body, the rubber mounts are modeled as springs and dampers, and the bodywork is modeled as flexible. An impedance function matrix is used to describe the dynamic relationship between the mounting points on the body.
2015-06-15
Journal Article
2015-01-2274
Paul R. Donavan, Bruce Rymer
Rumble strips are used commonly through the United States to alert drivers that they have wandered out of the lane of travel and need to take corrective action. In general, there are two conflicting requirements for rumble strips: producing sufficient warning for vehicle operators and minimizing the exterior noise that can create community annoyance. A measurement program was completed to assess driver input versus exterior noise generation for four vehicles designs and two approaches to rumble strip design. The vehicles included a small compact car, an immediate size car, a full sport utility vehicle, and a medium duty dump truck. The rumble strips included one of conventional design providing shorter wavelength input to the tire and one designed to provide longer wavelength, more harmonic input to the tire.
2015-06-15
Journal Article
2015-01-2263
Saeed J. Siavoshani, Prasad Vesikar
The intent of this paper is to summarize a comprehensive test-based approach developed at Siemens to analyze the door closing sound using structural and acoustic loads developed during the event. This study looks into the door closing phenomena from the structural interaction point of view between the door and the body of the vehicle. This method provides the design modification direction to improve the door closing sound and its quality. The study also quantifies the structural and acoustic loads developed at the interface mechanisms at the door-to-body frame interface during the impact event. Considering the transient nature of the door-closing event, a time domain transfer path analysis methodology is used to indirectly quantify the loads being developed between the latch and striker and different faces of door frames and body interfaces. The paper also predicts the equivalent acoustic loads developed at the interfaces between the door frame and the body.
2015-06-15
Journal Article
2015-01-2180
Almahdi Saleh, Michael Krak, Jason Dreyer, Rajendra Singh
Abstract This study examines clutch-damper subsystem dynamics under transient excitation and validates predictions using a new laboratory experiment (which is the subject of a companion paper). The proposed models include multi-staged stiffness and hysteresis elements as well as spline nonlinearities. Several example cases such as two high (or low) hysteresis clutches in series with a pre-damper are considered. First, detailed multi-degree of freedom nonlinear models are constructed, and their time domain predictions are validated by analogous measurements. Second, key damping sources that affect transient events are identified and appropriate models or parameters are selected or justified. Finally, torque impulses are evaluated using metrics, and their effects on driveline dynamics are quantified. Dynamic interactions between clutch-damper and spline backlash nonlinearities are briefly discussed.
2015-06-15
Journal Article
2015-01-2173
Srikumar C Gopalakrishnan, Teik Lim
Abstract Modeling of elastohydrodynamic lubrication phenomena for the spiral bevel gears is performed in the present study. The damping and the friction coefficient generated from the lubricated contact area will have profound effects on the dynamics of spiral bevel gears. Thus the damping value generated from this friction model will be time varying. This makes the use of constant and empirical damping value in the dynamics of spiral bevel gears questionable. The input geometric and kinematic data required for the elastohydrodynamic lubrication (EHL) simulations are obtained using Tooth Contact Analysis. A full numerical elastohydrodynamic lubrication simulations are carried out using asymmetric integrated control volume (AICV) algorithm to compute the contact pressures. The fast Fourier transform is used to calculate the elastic deformations on the gear surfaces due to contact load.
2015-06-15
Technical Paper
2015-01-2212
A. Elsawaf, H. Metered, T. Vampola, Z. Sika
Abstract Active vibration control is the most effective method used for suppressing vibrations from external sources. This paper presents the particle swarm optimization (PSO) algorithm to search about the optimum feedback controller gains for the active mount suspension, for the first time, to reduce the vibrations level of a structural system. It consists of vibrating mass and flexible beam subjected to an external disturbance. A mathematical model and the equations of motion of the structure system with an active mount suspension are simulated using Matlab/Simulink software. The active controller was designed to control the first three modes of the structure. The proposed PSO algorithm aims to minimize the acceleration of the suspended mass as the objective function with constraint of the actuator force. Vibrations level is examined theoretically in order to assess the effectiveness of the proposed controller.
2015-06-15
Journal Article
2015-01-2281
Shrirang Deshpande, Randall Allemang
Spectral maps and order tracks are tools which are susceptible to improper sensor location on rotating machinery and to measurement noise. On a complex/large rotating system, the major behavior in a particular direction cannot be observed by using standard digital signal processing averaging techniques on different sensor outputs. Also, measurement noise cannot be reduced by applying averaging - due to the slew rate of the system. A newly developed technique tested on experimental data, is presented which uses singular value decomposition (SVD) as its basis to improve the observability of rotating systems. By using data acquired from multiple accelerometers on a machine, singular values – obtained from a SVD of the cross-power matrix at each 2-D point in the frequency-RPM domain – can be plotted in a color-map format similar to a RPM spectral map.
2015-06-15
Journal Article
2015-01-2265
Murali Balasubramanian, Ahmed Shaik
Abstract Automotive manufacturers are being challenged to come up with radical solutions to achieve substantial (30-35%) vehicle weight reductions without compromising Safety, Durability, Handling, Aero-thermal or Noise, Vibration and Harshness (NVH) performance. Developing light weight vehicle enablers have assumed foremost priority amongst vehicle engineering teams in order to address the stringent Fuel Economy Performance (FEP) targets while facilitating lower CO2 emissions, downsizing of engines, lower battery capacities etc. Body sheet metal panels have become prime targets for weight reductions via gage reduction, high strength steel replacement, lighter material applications, lightening holes etc. Many of these panel weight reduction solutions are in sharp conflict with NVH performance requirements.
2015-06-15
Journal Article
2015-01-2285
Arne Nykänen, David Lennström, Roger Johnsson
Subjects who are well aware of what to judge commonly yield more consistent results in laboratory listening tests. This awareness may be raised by explicit instructions and training. However, too explicit instructions or use of only trained subjects may direct experiment results in an undesired way. An alternative is to give fairly open instructions to untrained subjects, but give the subjects a chance to get familiar with the product and context by, for example, riding a representative car under representative driving conditions before entering the laboratory. In this study, sound quality assessments of interior sounds of cars made by two groups were compared. In one group subjects were exposed to the same driving conditions that were later assessed in a laboratory listening test by taking them on a ride in one of the cars to be assessed, just before entering the laboratory. In the other group subjects made the laboratory assessments without prior car riding.
2015-06-15
Journal Article
2015-01-2284
Chris Hocking, Simon Antonov, Arsham Shahlari
The higher cylinder peak pressure and pressure rise rate of modern diesel and gasoline fueled engines tend to increase combustion noise while customers demand lower noise. The multiple degrees of freedom in engine control and calibration mean there is more scope to influence combustion noise but this must first be measured before it can be balanced with other attributes. An efficient means to realize this is to calculate combustion noise from the in-cylinder pressure measurements that are routinely acquired as part of the engine development process. This publication reviews the techniques required to ensure accurate and precise combustion noise measurements. First, the dynamic range must be maximized by using an analogue to digital converter with sufficient number of bits and selecting an appropriate range in the test equipment.
2015-06-15
Technical Paper
2015-01-2245
Mohammad Moetakef, Abdelkrim Zouani
Gerotor oil pumps are widely used in automotive engine and transmission lubrication systems. The positive displacement characteristic of the pump design along with tight clearances between its different components result in formation of excessive pressure ripples within the pump and the attached oil galleries. Since the pressure ripples act as the excitation source to the engine components any alignment between pressure ripples excitation frequencies and engine components modal frequencies exacerbate the oil pump tonal noises radiated by the engine components. For this reason, it is necessary to perform engine radiated noise analysis with oil pump as the excitation source to assess the NVH performance of the pump. This paper describes a CAE method addressing engine radiated noise and whine due to the excitation from a gerotor oil pump. The method involves a multidisciplinary approach including CFD, frequency-response structural analysis and acoustic analysis.
2015-06-15
Journal Article
2015-01-2255
Jun Kokaji, Masashi Komada, Masayuki Takei, Masaya Takeda
Abstract Although idling vibration is usually caused by 1st order of engine combustion force, other engine forces also occur at frequencies lower than the 1st order of combustion (called low frequency idling vibration in this paper). The drive-line of the Toyota Hybrid System II (THS II) has different torsional vibration characteristics compared to a conventional gasoline engine vehicle with an automatic transmission. Nonlinear characteristics caused by the state of backlash of pinions and splines influence changes in the torsional resonance frequency. The torsional resonance frequency of the drive-line can be controlled utilizing the hybrid system controls of the THS II.
2015-06-15
Journal Article
2015-01-2215
Thomas L. Lago
Abstract How to decrease noise and vibration exposure has been of interest for many years. Empirical data have indicated that too high dose values can create multiple problems to a human body - often severe. Some years back, the European Machinery Directive has increased the responsibility for manufacturers and employers to make sure limits are complying with legislation. Classical technology often consists of passive solutions aiming at trying to cut back on noise and vibration levels. For low frequency, these methods are often lacking the needed performance especially if weight should be considered at the same time. A smart combination of passive and active techniques can make a real difference. Today, with possibilities for low cost and embedded electronics and the rapid development of new actuators, a vast range of applications are possible for this combined combat approach, with a financial advantage as well.
2015-06-15
Technical Paper
2015-01-2250
Masahiro Akei, Nobutaka Tsujiuchi, Akihito Ito, Takayuki Yamauchi, Daisuke Kubota
This paper describes the identification of the sound source model for the diesel engine installed on the agricultural machine by Inverse-Numerical Acoustic analysis (INA), and the noise prediction using the sound source model identified by INA. INA is a method to identify surface vibrations from surrounding sound pressures. This method is applicable for a complicated-shaped sound source like an engine. Although many studies about INA have been conducted, these past studies are the studies on improvement of the identified accuracy and noise prediction in the free sound field or hemi-free sound field. The authors predicted accurately sound pressure level of engine enclosure using sound source model identified by INA and boundary element method (BEM). However, we have not yet verified the effectiveness of sound source model against the enclosure which has an absorption material and an opening.
2015-06-15
Technical Paper
2015-01-2296
Seunghyun Lee, Sungmoon Lee, Kyoungdoug Min, Insoo Jung
The diesel engine noise is classified into mechanical noise, flow dynamic noise and combustion noise. Among of them, the combustion noise is higher than the others due to diesel combustion high compression ratio and auto ignition. The injected fuel is mixed with air in ignition delay process, followed by simultaneous ignition of premixed mixture. This process results in rapid pressure rise which is the main source of the combustion noise. The amount of fuel burned during premixed combustion is mainly affected by the ignition delay. The EGR rate has impact on the ignition delay, and thus it influences combustion noise characteristics. Therefore, during the transient state, combustion noise characteristics changes as the EGR rate deviates from the target value. Therefore, in this study, the effect of EGR rate deviation during transient state the combustion noise is studied. The 1.6 L diesel engine with a VGT was used for the experiment.
2015-06-15
Technical Paper
2015-01-2294
Kodali Ajay Krishna, Pankaj Bhardwaj, Sanjeevgouda Patil, Mansinh Kumbhar
One of the primary excitation sources in a passenger car comes from the powertrain [1]. Refinement of powertrain induced noise is one of the major tasks during a full vehicle NVH refinement. For better fuel efficiency and emission norms, vehicle manufacturers need to focus drastically on reducing the weight and also at the same time achieving defined NVH targets. Due to ever increasing demand for reducing the development cycle of the design, most critical decisions have to be made at the concept stage of the powertrain design itself. Combustion excitation forces and powertrain radiated noise are the most important design factors along with the thermal, durability, and strength requirements that must be evaluated during concept stage and also during other stages of the development process. Solution time for calculating the radiated noise using the existing acoustic solvers is very high and requires very expensive resources (software and hardware).
2015-06-15
Technical Paper
2015-01-2299
Dhanesh Purekar
In comparison to medium duty and heavy duty diesel engines, NVH development of light duty diesel engines requires significant collaboration with the OEM. Typically, competitive benchmark studies and customer expectations define the NVH targets at the vehicle and subsequently cascaded down at the powertrain level. For engine manufacturing companies like Cummins, it is imperative to work closely with OEM to deliver on the NVH expectations. In certain situations, engine level NVH targets needs to be demonstrated in the OEM or 3rd party acoustic test facility for contract approvals. However, this is a difficult task to accomplish, considering the differences between acoustic test facilities and hardware, instrumentation, etc. In addition, engine itself is a big contributor to the noise variation. This technical paper documents one such case study conducted on a standalone light duty diesel engine in three different acoustic test facilities.
2015-06-15
Journal Article
2015-01-2298
Stephen Chittick, Mark Swindell, Samir Raorane
As part of the long-term business strategy Jaguar Land Rover (JLR) has designed and developed a new family of advanced, highly efficient engines for future models. The all-new Ingenium family of inline 4 cylinder engines will increase JLR's capability to offer high performance engines with class-leading levels of refinement, whilst ensuring continued significant reductions in vehicle emissions. This paper details the NVH development of the lead engine, a 2.0 litre common rail turbo diesel. The task from the outset of this new programme was to reduce the mass of the engine by 21.5kg, whilst also improving the structural attenuation by 5 dB in comparison to the outgoing engine. Improving the structural attenuation by 5 dB was not only a key enabler in reducing combustion noise, but also helped to achieve a certified CO2 performance of 99 g/km in the all-new Jaguar XE model, by allowing more scope for increasing cylinder pressure forcing without compromising NVH.
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