Browse Topic: Harshness

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Deployable Emergency Shutoff Device Blocks High-Velocity Fluid FlowsTBMG-349318/1/2019
NASA's Marshall Space Flight Center has developed a device and method for blocking the flow of fluid from an open pipe. The device plugs, controls, and meters the flow of gases and liquids. Anchored with friction fittings, spikes, or explosively activated fasteners, the device is well-suited for harsh environments and high fluid velocities and pressures. With the addition of instrumentation, it can also be used as a variable-area flow metering valve that can be set based upon flow conditions. With robotic additions, it can be configured to crawl into a pipe and then anchor and activate itself to block or control fluid flow.
Automotive Engineering: June 201919AUTP066/6/2019
Rethinking aluminum for NVH abatement Engineers, abandon those mastics! New "quiet" materials solutions are at hand. Paradigm shift in NVH A new wave of vehicle technologies is changing the way Brüel & Kjaer attacks noise, vibration and harshness. How a Tier 2 tackles NVH Saint-Gobain invested in anechoic testing so small components can make a big NVH difference. Reducing NVH through refined powertrain measurement The C1000 vastly simplifies measuring the mass matrix of heavy, odd shaped engines and powertrains. Foam for NVH solutions New innovations for a wide variety of sound-deadening applications. Long time coming: 2020 Corvette After six decades of teasing enthusiasts with intriguing concepts, Chevrolet is launching an all-new Corvette with its engine located where Zora intended-behind the driver. Protecting high-voltage circuits Yazaki readies a new solution for arc suppression in circuits of 48V or more. Editorial The unforgettable pyramid on the hood Supplier Eye Enter the dragon ICE researchers: 50% gasoline-engine efficiency in sight EMBATT looks to double the driving range of EVs Ford amped for new phase of hybrid-electric offensive As automotive climates shift, GKN ramps up its winter testing Mazda finally ready with Skyactiv-D for U.S. 2020 Escape: Ford's first crossover on new global FWD architecture New design for 2020 Mitsubishi Outlander Sport as brand awaits alliance's new platforms, products
Use of Active Vibration Control to Improve Vehicle Refinement while Expanding the Usable Range of Cylinder Deactivation2019-01-15716/5/2019
Cylinder deactivation has been in use for several years resulting in a sizable fuel economy advantage for V8-powered vehicles. The size of the fuel-economy benefit, compared to the full potential possible, is often limited due to the amount of usable torque available in four-cylinder-mode being capped by Noise, Vibration, and Harshness (NVH) sensitivities of various rear-wheel-drive vehicle architectures. This paper describes the application and optimization of active vibration absorbers as a system to attenuate vibration through several paths from the powertrain-driveline into the car body. The use of this strategy for attenuating vibration at strategic points is shown to diminish the need for reducing the powertrain source amplitude. This paper describes the process by which the strategic application of these devices is developed in order to achieve the increased usage of the most fuel efficient reduced-cylinder-count engine-operating-points.
Orzechowski, Jeff, Agnihotri, Gaurav, Juneja, Vikas
Open-Access Testbench Data for NVH Benchmarking of E-Machines under Electromagnetic Excitations2019-01-14596/5/2019
This paper presents an experimental setup dedicated to the analysis of noise and vibration due to Maxwell magnetic forces in electrical machines, a significant NVH source in hybrid and electric vehicles traction motors. Both electromagnetic excitations and structural response of the electrical machine are simplified to provide the first public benchmark of e-NVH phenomenon (electromagnetic Noise, Vibration, Harshness). The paper first describes how the testbench is designed and tested in order to reduce as much as possible modelling and experimental uncertainties. A Permanent Magnet Synchronous Machine topology used in EV/HEV applications is used to illustrate tooth modulation effect and interaction between radial and tangential force-induced vibrations, and designed to generate the resonance of several stator structural modes with simplified electromagnetic loading (open-circuit case). A larger air gap allows the insertion of a fine search-coil network to measure time and space distribution of the air-gap flux density and resulting Maxwell stress harmonics. Accelerometers are placed on stator tooth tips to capture tooth bending motion, as well as on the outer yoke of the stator. Besides vibration measurements, sound pressure and sound power level measurements are carried. Then, some of the key measurement results are presented including Experimental Modal Analysis, Operational Deflection Shapes, and Order Tracking Analysis, spectrograms and spatiograms, Sound Pressure Level and Sound Power Level measurements. The origin of the different NVH harmonics are analyzed and their physical origin is detailed. All the benchmark data is available in open access and can be used to compare different multiphysic simulation strategies of e-NVH in terms of accuracy and computing time, such as analytic, semi-analytic, numerical and hybrid methods using during electromagnetic, structural mechanics and acoustic calculations. The benchmark will be used in further work to study the most common noise mitigation strategies used in EV/HEV electric motors such as skewing, notching, pole and slot shaping, and harmonic current injection.
Devillers, Emile, Degrendele, Karine, Hecquet, Michel, Lecointe, Jean-Philippe, Le Besnerais, Jean, Cousin, Guillaume
Reducing Vehicle Interior NVH by Means of Locally Resonant Metamaterial Patches on Rear Shock Towers2019-01-15026/5/2019
Stringent regulations for CO2 emissions and noise pollution reduction demand lighter and improved Noise, Vibration Harshness (NVH) solutions in automotive industries. Designing light, compact and, at the same time, improved NVH solutions is often a challenge, as low noise and vibration levels often require heavy and bulky additions, especially to be effective in the low frequency regime. Recently, locally resonant metamaterials have emerged among the novel NVH solutions because of their performant NVH properties combined with lightweight and compact design. Due to the characteristic of stop band behavior, frequency ranges where free wave propagation is inhibited, metamaterials can beat the mass law, be it at least in some tunable frequency ranges. Previously the authors demonstrated how metamaterials can reduce the vibrations in a simplified shock tower upon shaker excitation. In this work, the authors apply the metamaterial concept on the real rear shock towers of a vehicle. In order to be able to benchmark the solution, a test vehicle is chosen, which is equipped in its commercial version with a 1.46 kg tuned vibration absorber (TVA) on each of the rear shock towers as NVH solution. It is shown that the metamaterial solution allows to achieve similar interior NVH performance, while reducing the added mass by 48%. The metamaterial additions are realized through additive manufacturing and they are designed to be effective around 190 Hz, as was the case for the original solution. Both experimental results and numerical validation of a road test are presented.
Sangiuliano, Luca, Claeys, Claus, Deckers, Elke, De Smet, Jasper, Pluymers, Bert, Desmet, Wim
Study of the Sliding Door Shaking Problem and Optimization Based on the Application of Euler’s Spiral10-02-03-001410/3/2018
This study focuses on the sudden shaking phenomenon of a sliding door passing through a corner. This phenomenon requires attention because shaking during movement can lead to a harsh operation feeling and a short service life. An experiment based on a test setup was conducted, and the sudden change in the acceleration of a sliding door panel was measured. Based on multi-body dynamics (MBD) analysis and a rigid-flexible coupled model of the sliding door system, the cause of the sudden shaking was determined to be the discontinuous curvature of the middle rail trajectory. A transition curve was proposed as the solution for the discontinuous curvature, and Euler’s spiral was applied in the redesign of the middle rail trajectory. Verified by simulations, the results exhibit considerable improvement in sliding door movement stability, with large reductions in the maximum center of mass (CM) acceleration and guide roller impact force.
Chen, Ziming, Li, Luoxing, Wu, Yunlong
2021-12-29.TEST Delivering Maximal Robustness to Your Automotive ECU on a Frugal Budget *CSP Meta Testing*2018-01-00024/3/2018
Automotive engineering has been a game of delivering more value with minimal resources confronting conflicting design choices at every design step. As more and more electronics enters the game, it becomes imperative to critically evaluate various design choices to deliver a robust hardware backbone which guarantees a robust performance on an ever-reducing budget. Hardware interface with the outside environment in particular needs to be equipped with a significant robustness. Harsh transients, tough environmental conditions, further complicate the rules to the game.
Vaidya, Vishwas
Simulation of Dynamic Gas Cavity Effects of a Tire under Operational Conditions2018-01-06824/3/2018
The authors are responsible for the development of a structural 3D shell based bead-to-bead model with sidewalls and belt that separately models all functional layers of a modern tire [4]. In this model, the inflation pressure is modeled as a uniform stress acting normal to the shell’s inner face. The pressure can vary depending on the application: prescribed by the MBS-tool to align to a constant pressure specified for a vehicle or scenario, but it can also be modified dynamically to simulate e.g. a sudden pressure loss in a tire [1]. For many applications, this description of the inflation pressure as a time dependent quantity is sufficient. However, there are applications where it is needed to describe the inflation gas using a dynamic gas equation (Euler or Navier-Stokes). One such example is when the tire model is used in NVH (Noise-Vibration-Harshness) applications where the frequency range extends the 200 Hz range. For passenger car tires, a first mode of the inflation gas is at around 200-250. This mode couples with the tire structure and yields significant peaks in the spindle force spectrum, which have to be considered in the NVH assessment of a car. In this paper, we show the effect of modeling the inflation gas of a tire by an isentropic compressible Euler equation and couple it to the tire dynamics in the nonlinear transient application range. After motivation and validation of the overall model by comparison with respective measurements, we also describe how to derive a linear model from the overall transient tire model, that can then be used in linear FEM based NVH-tools. It can be observed that the tire rotation will yield a split in the cavity mode which increases with rotational velocity, an effect that can also be correctly predicted by the linearized model.
Gallrein, Axel, Baecker, Manfred, Guan, Jianmin
Interior Noise and Vibration Reduction of BRT - Premium Segment Bus2017-01-18666/5/2017
Urbanisation has led to an increased need for mobility in public transportation. Sensing the unfolding worrisome scenario, many countries have taken up different mass rapid transit solutions to alleviate the problem and restore the free flowing traffic. BRT should have been the logical choice particularly considering the lower capital costs involved and faster implementation. Comprehensibly the expectations of this class of vehicles will be high in term of quality and comfort to the passengers. Level of vibration and noise is an important indicator to evaluate vehicle's ride comfort. The challenges are to design the high powered Powertrain and Air Conditioning system nonetheless low interior noise, vibration and harshness correspondents to personal cars. This paper is an invention of, development work done in interior noise refinement of a bus. A prototype bus manufactured to meet all the requirement of BRT - premium segment urban bus. The prototype was almost meeting the entire required specifications, excluding interior noise and vibrations. The rear zone of the interior was the major concern of NVH levels, which demands to carry out the root cause analysis. There were various structure-borne and air-borne sources contributing to increase in NVH levels. Design and development iterations were conducted on the vehicle to achieve the well significant noise and vibration reduction and increased comfort to the passengers.
Jawale, Pradeep, Karanth, Nagesh
Electric Traction Motors for Cadillac CT6 Plugin Hybrid-Electric Vehicle2016-01-12204/5/2016
The Cadillac CT6 plug-in hybrid electric vehicle (PHEV) power-split transmission architecture utilizes two motors. One is an induction motor type while the other is a permanent magnet AC (PMAC) motor type referred to as motor A and motor B respectively. Bar-wound stator construction is utilized for both motors. Induction motor-A winding is connected in delta and PMAC motor-B winding is connected in wye. Overall, the choice of induction for motor A and permanent magnet for motor B is well supported by the choice of hybrid system architecture and the relative usage profiles of the machines. This selection criteria along with the design optimization of electric motors, their electrical and thermal performances, as well as the noise, vibration, and harshness (NVH) performance are discussed in detail. It is absolutely crucial that high performance electric machines are coupled with high performance control algorithms to enable maximum system efficiency and performance. Specifically, key challenges toward that goal are inverter voltage utilization, for maximum power capability and accurate current control for torque production. We focus of on the specific challenges in controlling induction machines where the leading requirement form the machine design side to lower leakage inductance has negative ramification on the controllability of the machine.
Jurkovic, Sinisa, Rahman, Khwaja M., Savagian, Peter, Dawsey, Robert
Geartrain Noise Optimization in an Electrical Drive Unit2015-01-23656/15/2015
Alternative powertrains, in particular electric and plug-in hybrids, create a wide range of unique and challenging NVH (noise, vibration & harshness) issues in today's automotive industry. Among the emerging engineering challenges from these powertrains, their acoustic performances become more complicated, partially due to reduced ambient masking noise level and light weight structure. In addition, the move away from conventional displacement engines to electrical drive units (EDU) has created a new array of NVH concerns and dynamics, which are relatively unknown as compared to the aforementioned traditional setups. In this paper, an NVH optimization study will be presented, focusing on four distinct factors in electric drive unit gear mesh source generation and radiation: EDU housing and bearing dynamics, gear geometry, EDU shafting torsional dynamics, and EDU housing structure. The study involves intensive FEA modeling/analyses jointly with physical validation tests. All four factors are evaluated for their contributions to noise performance, as well as their theoretical performance boundaries. Results are presented, which demonstrate the ability of this engineering approach to both optimize mass and performance of EDU products.
Sun, Zhaohui, Steyer, Glen, Ley, Jason
Low-Frequency Noise Transfer Path Identification Study for Engine Sub-Frame Utilizing Numerical Simulation2015-01-23616/15/2015
Nowadays, by the introduction of significant advances in automotive industries, noise, vibration and harshness (NVH), in the position of the main comfort attribute, plays a crucial role in marketing and passenger satisfaction. In order to cope NVH problems, three main actions are taken by NVH engineers for reducing perceived level of noise in cabin: Noise reduction in sources, Noise path treatment and Noise control at receiver. Among these approaches, those pertain to modification of noise pass, through structure and air, to the cabin are more prevalent in automotive applications. Accordingly, identification of noise paths that dominantly contribute to sound and vibration transfer to cabin phenomenon should be dealt with importance. In practice, engine vibration transmitted through sub-frame attachments to body can induce high level of noise and vibration to the passenger cabin. In this research, at first stage, optimization of shell thicknesses for four main engine sub-frame components is performed to minimize noise transfer function at driver's ear positions. Taguchi methodology is chosen for this matter as a robust method which reduces number of simulations significantly. Then, transfer path identification is performed for the optimized engine sub-frame configuration with six attachment mounts to the body structure. For this aim, numerical simulation is utilized for virtual analyses. Finite element method is used to simulate cabin vibro-acoustic behavior of a B-segment sedan car exited by engine vibration. Resultantly, contribution of each attachment point in the transferred noise to driver's ear is identified through calculating sound pressure level at critical frequencies in the designated points of cabin cavity.
Beigmoradi, Sajjad
Study on the Influence of Material Parameters to Acoustic Performance2015-01-22006/15/2015
Acoustic performance of auto interiors is definitely important to control the NVH (noise, vibration, and harshness) performance inside a vehicle, and it is determined by the material parameters, such as density (ρ), thickness (d), open porosity (OP), airflow resistivity (σ), tortuosity (T), viscous characteristic length (VCL), thermal characteristic length (TCL), young's modulus, poisson's ratio, and damping coefficient. Firstly, by making different felt samples (of different surface density and thickness), the sound absorption performance and related parameters were obtained. Then the correlation between the parameters and the sound absorption coefficient (SAC) was summarized. Through this method, database of acoustic parameters and the corresponding SAC for porous materials can be established and sound package design and adjustment can be easily conducted based on the database.
Zhou, Guojian, Tian, Xiujie, Zhu, Keda, Huang, Wei, Wentzel, Richard E., Care, Melvyn J.
MMLV: NVH Sound Package Development and Full Vehicle Testing2015-01-16154/14/2015
The Multi Material Lightweight Vehicle (MMLV) developed by Magna International and Ford Motor Company is a result of a US Department of Energy project DE-EE0005574. The project demonstrates the lightweighting potential of a five passenger sedan, while maintaining vehicle performance and occupant safety. Prototype vehicles were manufactured and limited full vehicle testing was conducted. The Mach-1 vehicle design, comprised of commercially available materials and production processes, achieved a 364 kg (23.5%) full vehicle mass reduction, enabling the application of a 1-liter 3-cylinder engine resulting in a significant environmental benefit and fuel reduction. This paper includes details associated with the noise, vibration and harshness (NVH) sound package design and testing. Lightweight design actions on radiating panels enclosing the vehicle cabin typically cause vehicle interior acoustic degradation due to the reduction of panel surface mass. To reduce this deficiency, an MMLV vehicle sound package development was conducted to improve NVH performance of MMLV with ultra-light weight sound package technologies. The project goal was to improve acoustical performance of MMLV by 2 dB without increasing the total sound package weight of “Vehicle A” which is the baseline vehicle for MMLV. This paper presents the lightweight sound package development process for MMLV as well as the full vehicle NVH test results in the high frequency range of 200-10000 Hz. Floor damping treatment strategy and body NVH test results in the low frequency range are also discussed. Full vehicle SEA (Statistical Energy Analysis) simulations are used to evaluate and guide the design and development of MMLV sound package. The final MMLV vehicle sound package design improves the vehicle's engine noise reduction (ENR) by 3.3 dB and improves the front tire patch noise reduction (TPNR) by 1.2 dB without increasing the baseline sound package weight.
Gur, Yuksel, Pan, Jian, Huber, John, Wallace, Jeff
On Finite Element Tyre Modal Analysis2015-01-15184/14/2015
Three-dimensional (3D) Finite element (FE) tyre models have been widely used for tyre design, vehicle design and dynamic investigations. Such tyre models have the inherent advantage of covering a wide range of tyre modelling issues such as the detailed tyre geometry and material composition, in addition to an extensive coverage of tyre operational conditions such as the static preload, inflation pressure and driving speed. Although tyre vibration behaviour, in different frequency ranges are of general interest, both for the vehicle interior and exterior noise, the present study is limited to a frequency of 100 Hz which is prevalent in most road induced (Noise, Vibration, Harshness) NVH ride and handling problems. This study investigates tyre vibration behaviour using a proprietary FE code. Such investigation plays an important role in the study of vehicle dynamics. In particular, the eigen-pair i.e. the natural frequencies and mode shapes of the tyre in a real eigenvalue analysis for different operational conditions of pressure, pre-load and restraint conditions are extracted and compared with experimental results.
Bolarinwa, Emmanuel O., Olatunbosun, Oluremi
Application of Laminated Composite Materials in Vehicle Design: Theories and Analyses of Composite Beams2013-01-19435/13/2013
With rising fuel prices, lightweight structures and materials (like composites) are receiving more attention. Composite materials offer high stiffness to weight and strength to weight ratios when compared with traditional metallic materials. Traditionally, composite materials were generally costly which made them only attractive to very limited industries (e.g., the defense industry). Advances in their manufacturing and new innovations have brought the cost of these materials down and made them reasonably competitive. They have gained more and more usage in the last 3 decades in the aerospace industry and have recently been gaining more usage in the automotive industry. In automotive design, they yield lighter structures which have positive impact on attributes like fuel economy, emission and others. Proper modeling and analyses need to be performed to make sure that other attributes (e.g. durability, noise, vibration and harshness or NVH) are assessed properly and remain competitive. Composite materials offered for real applications in the automotive industry vary from thermo-plastics to laminated and fiber-reinforced structures. This paper will focus on laminated beams and their applications in the auto industry.
Qatu, Mohamad, Abu-Shams, Mohammad, Hajianmaleki, Mehdi
Application of Laminated Composite Materials in Vehicle Design: Theories and Analyses of Composite Shells2013-01-19895/13/2013
With rising fuel prices, light weight structures and materials (like composites) are receiving more attention. Composite materials offer high stiffness to weight ratio when compared with traditional metallic materials. Traditionally, composite materials were generally costly which made them only attractive to very limited industries (e.g., the defense industry). Advances in their manufacturing and new innovations have brought the cost of these materials down and made them reasonably competitive. They have gained more and more usage in the last 3 decades in the aerospace industry and have recently been gaining more usage in the automotive industry. In automotive design, they yield lighter structures which have positive impact on attributes like fuel economy, emission and others. Proper modeling and analyses need to be performed to make sure that other attributes (e.g. noise, vibration and harshness or NVH) are assessed properly and remain competitive. Composite materials offered for real applications in the automotive industry vary from thermo-plastics to laminated and fiber-reinforced structures. This paper will focus on composite shells and their applications in the auto industry.
Qatu, Mohamad, Zannon, Mohammad, Mainuddin, Golam
Design and Benefits of Dynamic Skip Fire Strategies for Cylinder Deactivated Engines2013-01-03594/8/2013
Cylinder deactivation is a fuel consumption reduction technology for throttled internal combustion engines and other engines with thermal efficiency loss at part cylinder load. Recent production implementations, deactivating fixed sets of cylinders under part-load operating conditions, have had limited “fly zones” due to issues with drivability and noise, vibration and harshness (NVH). Dynamic skip firing, which in its ultimate form incorporates anytime, any-cylinder deactivation, continuously varies the number of firing cylinders, along with cylinder load, obtaining flexible control of acoustic and vibrational excitations from the engine, and allowing an expanded operational envelope with fewer drive ability/NVH issues. This paper outlines design considerations of dynamic skip fire operational strategies, discusses implementation of the system on a vehicle, and presents benefits to fuel economy and NVH.
Wilcutts, Mark, Switkes, Joshua, Shost, Mark, Tripathi, Adya
The Development of FR-Based 4WD Multi-Link Suspension2013-01-12354/8/2013
In this paper FR (Front Engine, Rear wheel Drive) based 4WD 5-link independent suspension systems are introduced which are developed for low friction road stability in the winter. The arrangement of the lower control arm of the newly developed suspensions has been changed in order to correspond to 4WD layout. And basic performance is satisfied due to the addition of the driveline. Also NVH (Noise, Vibration and Harshness) performance has improved, to enhance the comfort of the vehicle
Jung, DaeWoo, Lee, Jae Kil, Lee, Byung-Kyu, Kim, Seon Pyung
LED Power SuppliesTBMG-160953/1/2013
Green Watt Power (Concord, CA), a division of Calex Mfg. Co., has announced CSA/UL agency approvals on the Green Watt Power offering of LED Constant Current power supplies. The GLC Series offers solutions from 18 Watts to 150 Watts. All GLC models are enclosed to IP67 standards and well suited for virtually all LED lighting applications including indoor, outdoor, signage, and thermally harsh and damp environments. All models have a universal AC input and are agency approved to 277 VAC. Agency approvals include UL/CSA 8750 and 1310 class 2 or 1. All GLC models feature over voltage, over current, over temperature protection and are RoHS compliant. All models are designed and built for consistent performance and high reliability and come with a Five Year Warranty.
Analysis of Ventilated Disc Brake Squeal Using a 10 DOF Model2012-01-18279/17/2012
Squeal of disc brakes is considered as a main source of discomfort for passengers. Typically 1 to 4 kHz noise is considered low frequency squeal and ≻8 kHz noise is considered high frequency squeal. It is a significant problem in passenger vehicles for the comfort of the passengers and a significant financial problem for industry too. Many manufacturers of brake pad materials spend up to fifty percent of their engineering budgets on noise, vibration and harshness (NVH) issues. Squeal noise is strongly correlated to the squeal index and degree of instability of the brake system assembly. Decreasing this squeal noise to some extent during braking is very important matter for the comfort of passengers. So, a mathematical prediction model of 10-degree-of-freedom has been developed to study the effect of different brake components parameters on the degree of instability and squeal index of the brake system. The model has considered such factors as the distance between clamping bolts of the caliper which was not fully covered previously besides some other factors as width and thickness of the friction material. Complex eigenvalue analysis by MATLAB has been used to predict the unstable frequencies of the ventilated disc brake system assembly. It is evident from the analysis that squeal noise of the brake decreases with increasing semi-distance between the clamping bolts of the caliper and with the increase in friction material thickness. However, the squeal noise decreases with increasing the width of the friction material and Young's modulus of both rotor and friction material. The results also show that the width of the friction material has a major effect on the occurrence of the squeal noise of the brake assembly and as it increases, the squeal index decreases.
Ahmed, Ibrahim
MEMS Deformable Mirrors Enable Imaging of Earth-Sized Extra-Solar PlanetsTBMG-144858/1/2012
The NASA-sponsored space exploration project, PICTURE (Planet Imaging Concept Testbed Using a Rocket Experiment), seeks to obtain a direct image of an extra-solar giant planet. The PICTURE telescope, which uses a BMC deformable mirror for adaptive optic wavefront control, was launched aboard a NASA sounding rocket in October 2011. Preliminary data show that the MEMS deformable mirror was successful in its operation.
Use of Heat Reflective Coating for Vibration Insulation Rubber Parts in Automotive Applications2012-01-11824/16/2012
Vibration insulation rubber parts are used in automotive applications to meet noise, vibration, and harshness (NVH) requirements. Some of these parts are located in high heat areas in the engine bay or near the exhaust pipe. Often, the parts need to be protected from heat to reduce material degradation, decrease in NVH benefit, and part failure. A number of methods are used to lower the part temperature. Layout, material change, and part shielding are common methods. Each of these methods has its own positives and negatives. A heat reflective coating was developed for use on these parts to provide an additional option to lower the part temperature. The coating is applied to the surface of the rubber to protect against radiant heat. It can match the elongation of the substrate rubber without impacting durability or the static and dynamic properties. The use of a heat reflective coating provides a reduction of the rubber substrate surface temperature in a laboratory setting using radiant heat as well as during on-vehicle testing.
Baumbarger, Michael A.
Sound Field Visualization using Spherical Holography2010-01-14206/9/2010
Beamforming based on measurements with a spherical microphone array is a recognized technique for localization of noise sources. The method is very efficient for getting a quick overview of the positions of the most dominant sources. However, when more detailed information about the radiation from a source is needed, acoustical holography is normally more suitable, because it provides the actual acoustical quantities (pressure, velocity and/or intensity) at positions on or near the source surface, whereas beamforming only gives a directional map of contribution at the array position. Even though spherical arrays are most often used for beamforming they can also be applied for holography purposes. This means that with the same hardware beamforming can be used to identify a noise source, and then the array can be moved closer to the source to get a clearer picture of the radiation by using holography. Also, beamforming has a poor directional resolution at low frequencies, whereas holography performs best at low-to-mid frequencies, which means that the two methods supplement each other well in the frequency domain. This paper presents some results (simulations and real measurements) based on holography and beamforming using a rigid sphere with flush mounted microphones.
Gomes, Jesper, Haddad, Karim, Hald, Jorgen
Corrosion Evaluation of Army and Automotive Materials in the Hawaiian Islands – 3-Year Update2008-01-11544/14/2008
The US Army operates in many harsh and demanding environments throughout the world, which are highly corrosive. However, there lacks a basic understanding of the severity of these environments and their impact on the Army's materiel. To better understand this impact and broaden their database of information, the Army has established test sites on the Hawaii islands. These sites represent various climatic conditions the Army operates in. In these locations panel exposure of Army and automotive systems have been made to compare performance with that documented in the continental US by the SAE ACAP and past Army programs. Recently the first set of samples exposed have completed three (3) years of exposure. A secondary set has reached its first year of exposure and a third set have completed three (3) months of exposure. This paper will present a summary of the three year results and future work to be completed.
Repp, John, Handsy, I. Carl
Corrosion Evaluation of Army and Automotive Materials in Hawaii2006-01-16494/3/2006
The US Army operates in many harsh and demanding environments throughout the world, which are highly corrosive. However, there lacks a basic understanding of the severity of these environments and their impact on the Army's materiel. To better understand this impact and broaden their database of information, the Army has established test sites on the island of Oahu, Hawaii. These sites represent various climatic conditions the Army operates in. In select locations panel exposure of Army and automotive systems have been made to compare performance with that documented in the continental US by the SAE ACAP and past Army programs. This paper will present the details of this project and results through 1-year of exposure for this multi-year effort.
Repp, John, Sampson, Sheri, Handsy, I. Carl
Miniature Robotic Submarine for Exploring Harsh EnvironmentsTBMG-66110/1/2004
The miniature autonomous submersible explorer (MASE) has been proposed as a means of scientific exploration—especially, looking for signs of life—in harsh, relatively inaccessible underwater environments. Basically, the MASE would be a small instrumented robotic submarine (see figure) that could launch itself or could be launched from another vehicle. Examples of environments that might be explored by use of the MASE include subglacial lakes, deep-ocean hydrothermal vents, acidic or alkaline lakes, brine lenses in permafrost, and ocean regions under Antarctic ice shelves.
Light-Emitting Diodes in Automotive Forward Lighting Applications: Materials Engineering Solutions to Fundamental Challenges2004-01-02253/8/2004
Innovative LED lighting solutions have become more prevalent in automotive signal lighting during the past few years. However, to date, there has been no penetration into the various forward lighting applications. This is primarily due to significant materials engineering and optical design challenges that have made LEDs impractical or impossible to use in forward lighting applications where harsh environs and exacting beam pattern requirements exist. This paper will focus on these challenges, discuss recent progress in LED technology and, for the first time, demonstrate an LED source with comparable luminance to a filament bulb light source.
Kern, R. Scott
Flexible Multilayer Designs Provide Cost Effective Packaging Solutions1999-01-01623/1/1999
This paper discusses a variety of manufacturing techniques which have been developed to produce cost effective multilayer interconnects while overcoming the harsh environmental conditions imposed by the Automotive Industry. A comparison is made to the transition of Military Rigid-flex technology and materials needed to overcome the aerospace environment.
DiPalermo, Joseph A.
Voice-Driven Information Access in the Automobile98C03210/19/1998
Until recently, the user experience in the automobile consisted of driving and listening to the radio. With recent advances in wireless communications and speech recognition, however, the possibilities for information access in the automobile have expanded tremendously. We describe our voice recognition technology and how it enables convenient voice interaction with information from the Web, E-mail, voice mail, and electronic map services. We also describe recent advances we have made in our technology to operate robustly in the harsh environment of the automobile. With these advances, we foresee driving in the future becoming much more safe, productive, convenient, and fun.
Hemphill, Charles T., Agarwal, Rajeev, Muthusamy, Yeshwant K., Gong, Yifan
Microelectronics-Microhybrid Technology98C03910/19/1998
The development in electronics for automotive application shows a high speed of improvement over the last 20 years regarding downsizing of all components. This could be achieved despite the harsh environmental conditions we find in vehicles, especially in the engine compartment. Big changes have always required the development of new technologies regarding the production of electronic components. The paper shows technologies which are right now under development to allow the next steps regarding downsizing as well as some examples of possible applications. There is also information regarding the current obstacles for improvements beyond this point as well as basic ideas how to overcome some of them.
Kilgenstein, Peter
Comparisons of Thermocouple, Time-Averaged and Mass-Averaged Exhaust Gas Temperatures for a Spark-Ignited Engine8200502/1/1982
Accurate knowledge of engine exhaust gas temperatures is important for engine design and diagnostic efforts. To survive the harsh exhaust gas environment, most practical devices for determining exhaust gas temperatures are relatively large. Because of their size, these devices do not provide instantaneous gas temperatures but provide a single equilibrium temperature. This investigation compared computed thermocouple equilibrium temperatures of the exhaust gas to computed time-averaged and mass-averaged gas temperatures for nine different engine conditions. Mass-averaged gas temperatures are directly related to the exhaust gas energy whereas thermocouple and time-averaged gas temperatures are not directly related. For most of the engine conditions of this study, the exhaust gas energy based on time-averaged gas temperatures was about 10% lower than the energy based on mass-averaged temperatures and the energy based on thermocouple temperatures depended on the thermocouple properties. The mass-averaged, time-averaged and thermocouple exhaust gas temperatures varied as a function of engine conditions. For a spherical thermocouple with a diameter of 0.076 cm and an emissivity of 0.85, the computed thermocouple equilibrium temperature was about 20 K lower than the time-averaged exhaust gas temperature for variations in engine speed, spark timing and equivalence ratio. Variations in engine load did not appreciably change the thermocouple equilibrium temperature, however the time-averaged gas temperature decreased for increasing engine loads. The thermocouple temperature for a fixed engine condition was examined as a function of thermocouple emissivity, diameter and shape. The calculations resulted in thermocouple temperatures which increased for decreasing values of emissivity for all thermocouple diameters and for decreasing values of the thermocouple diameters for moderate to high emissivities. For low emissivities, decreasing thermocouple temperatures were obtained for decreasing values of the thermocouple diameter.
Caton, J. A.
PASSENGER CAR NOISE - ENGINE HARSHNESS5200281/1/1952
BALL, L. M.
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