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Aerodynamic Noise of Ground Vehicles | As engine, tire, and other automobile noise is reduced and as driving speeds increase, aerodynamic noise sources on ground vehicles are becoming relatively more important. They often dominate at cruise speeds of 65 mph. Aspiration and leak noise are strong sources but generally can be controlled by known methods. Turbulent pressure fluctuations due to separated and vortical flows are also strong sources. Much interior noise is caused by transmission of these external pressure fluctuations through windows and other surfaces. The paper presents the variety of aeroacoustic sources on automobiles and reviews the state of experimental data, of analysis methods, and noise reduction principles. A new correlation method for predicting external fluctuating pressures in separated regions is presented. |
Climate Measurements for Glass with Different Energy Properties | Recent developments in glass treatment techniques have made it possible to improve vehicle compartment climate considerably. At the same time, it has become obvious that traditional temperature measurements do not cover the total need for describing climate properties. This is due to the fact that human heat balance, which is the fundamental process behind feeling cold or hot, is a function not only of temperature but also of draft and radiation. Coating glass is one means of preventing solar radiation from coming into the compartment. In doing so, the solar heat load through the glazing can be reduced by some 50 %. This, of course, gives a lower compartment temperature in parking conditions and also a faster cool-down in hot climate. It has two major secondary impacts on the human being: At a given air flow through the compartment, the necessary inlet temperature is increased, thereby causing less draft. Direct radiation on body surfaces is also reduced. The total evaluation of glass with reflecting or absorbing properties must therefore include measurements with instruments like the Bruel & Kjaer comfort meter or the Voltman system as presented in SAE reports nos. 850042 and 890049. The latter system, which gives a total picture of heat load on different body parts in a given situation, is of course the most sophisticated method for this part of the evaluation. In this paper, some suggestions are given for testing routines. They include: parking heat-up and idling cool-down tests. Voltman on-road testing and simulated on-road testing outdoors. |
Development of a Test Procedure for Quantifying Performance Benefits of Solar Control Glazings on Occupant Comfort | The evaluation of the performance benefits of solar load reducing glazings using production vehicles is key to the establishment of the product cost/benefit ratio. Climatic windtunnels normally used to evaluate heat gain and vehicle cooldown can not provide true solar simulation. Comparative testing using a test car and a control vehicle must therefore be conducted outside in uncontrollable ambient conditions. The subject paper deals with the development of a testing methodology capable of quantifying thermal performance differences, as low as 5%, resulting from component differences, including glazings. The procedure described includes the use of B & K Thermal Comfort Meters to standardize the refrigeration system performance and to evaluate the rate of vehicle interior cooldown. Data taken during summer test programs in the Southwest for evaluation of heat absorbing glazings will be reviewed. Data to be presented include interior air and surface temperatures during soak testing and cooldown comparisons under city drive conditions. The general relationship of comfort meter data to driver comfort index will also be discussed. |
Solar Control Glass with Neutral Color for Automobiles | This paper describes monolithic solar control glass with high durability and neutral color (colorless reflection) for automotive windows. Layer systems of the solar control coating are composed of double layers (oxide/nitride/glass) and triple layers (oxide/nitride/oxide/glass), where a titanium nitride film is chosen for solar energy reduction and a novel zirconium based oxide film with a low refractive index is used as a protective layer together with reducing optical interference color. The nitride film and the oxide film are prepared by reactive dc magnetron sputtering from a titanium target and an alloy target without intentional substrate heating, respectively. Durability of the double layer coating is investigated against abrasion, chemicals and weathering. When the coating is applied to all windows of a passenger car, the reduction of a solar heat load is evaluated through an air-conditioner at simulated car speed under simulated solar radiation. |
Non-Destructive Replication Technique for the Examination of Phosphate Crystal Morphology on Vehicle Assembly Lines | Destructive or indirect methods have been available for evaluating phosphate crystal morphology on car bodies pretreated on a vehicle production line. Either the panel in question is removed, thereby destroying the car, or flat panels are hung in the window openings with the assumption that the same morphology exists over similar substrate surfaces on the stamped autobody. The replication technique described in this report has proven to be a viable option for examining the phosphate crystal morphologies present on various automobile substrates. The details of this replication technique along with crystal morphologies associated with different substrates and degrees of forming are included in this report. |
Air Conditioning Electric Vehicles with an Electronically Driven Variable Speed Scroll Type Compressor | A realistic air conditioning system for electric vehicles, (EV), which minimizes the sacrifice of drive range is proposed in this paper. A variable speed semi-hermetic scroll compressor and an automatic louver outlet air temperature control method for a small delivery van are used to attain suitable cooling performance and interior temperature controllability with acceptable noise characteristics. This air conditioning system, (A/C), offers a pre-cooling feature simply by tapping power from commercial electricity outlets before departing for service. The effect of a practical heat influx reduction applied to the vehicle, and of condenser improvement, is evaluated in terms of the electric power consumption and the actual sacrifice of the vehicle's drive range. |
On-Line Paintable Polypropylene Compounds for Automobile Body Panels | The use of plastics to make the bumpers, doors, fenders and other exterior body panels has increased greatly in recent years. Efforts have been made to achieve on-line paintability so that plastic and steel body parts can be painted at the same time. This has already been accomplished for polyamides and certain polymer alloys such as polyphenylene ether/polyamide. In the field of general-purpose plastics such as polypropylene, recent advances in composite material technology have made it possible to develop general-purpose plastics that display properties comparable to those of engineering plastics. We have succeded in developing new polypropylene compounds which combine excellent thermal properties, high impact strength, and low coefficient of linear expansion. In addition, they can be painted on-line in lamp finisher and front bumper applications. |
Development of Rubber Contacts Used for Power Window Switches | We have developed a power window switch unit for use in multiplex wiring systems for automobile doors. As the systems are multiplexed, signal switches mounted on PC boards prove to be more advantageous than conventional switches having a metal spring and metal contact. We chose to use a rubber contact in one of the signal switches, and combined a good operational feeling into the rubber contact, thereby succeeding in designing a switch structure that requires less parts. We expressed the operational feeling of the switch by four values, and designed the switch with the help of CAE to meet each of the values. We could therefore develop a rubber contact with an operational feeling as high as we had aimed without the need to make any prototypes. |
On Determining the Relationship Between Vehicle Value and Interior Noise | A PC based survey tool has been used to measure the value of a luxury vehicle as a function of its interior noise level at 70 mph. Two straight lines were required to fit the change in value (measured in dollars) with noise level depending upon whether noise was greater or less than a baseline level of 66 dB(A). The slopes of the lines differed by a factor of two with the value loss curve asociated with a noise increase from the baseline level being the steeper of the two. A difference in the value relationships between gains and losses in this manner is expected from prospect theory. When the noise level in dB(A) was adjusted to represent a sones-like scale using a conversion based upon a broadband noise spectrum, the measurements followed a single straight line reinforcing the view that the sones scale is more nearly a ?쐏ure??psychometric scale than dB(A). The results also suggest that, when persons are asked for their willingness to pay, their response threshold for losses is much more sensitive than their threshold for gains. The findings are discussed in terms of their implications on designing automobiles for competitive markets. |
Safety Testing and Evaluation of Polycarbonate Vehicle Glazing Using Full Scale Crash Testing Procedures | This paper presents the results of a comprehensive research program addressing the safety issues pertaining to using Polycarbonate glazing for non-windshield vehicle glazing. A series of crash test procedures were used to evaluate the Polycarbonate glazing alternative. The test procedures utilized included High Speed Lateral Impact (HSLI), Narrow Object Intrusion or Pole Impact, Dynamic Rollover, and Inverted Vehicle Drop tests. It should be noted that component-level dynamic impact testing of a variety of Polycarbonate designs was previously conducted as part of this ongoing research program [1]. This testing included 40 lb guided headform and Free Motion Headform (FMH) testing. In regard to vehicle glazing, there are a number of important occupant safety issues. These include occupant containment, injury due to occupant impact with glazing, and laceration. Throughout the project, emphasis was placed on the careful monitoring of the test results with regard to these three issues. The intent of this study was not to specifically highlight the safety benefits of Polycarbonate glazing, but more to fully investigate the Polycarbonate glazing alternatives to determine whether there are increased safety risks accompanying a switch to this type of glazing. The vehicles that were used for this project are quite popular to the North American market. These vehicles included a 1997 Ford Taurus, a 1997 Chevrolet Cavalier, and a 1997 Dodge Grand Caravan. For each Polycarbonate test, the vehicle's non-windshield Tempered Glass glazing was replaced with 4 mm Polycarbonate glazing. The Polycarbonate glazing was bonded into the vehicle using an automotive adhesive common to the industry. Although this approach is not feasible for moveable window applications, one of the reasons it was chosen was to produce the highest possible loads on the Polycarbonate window. Throughout this study, it became increasingly clear that there are many safety issues to consider with both Polycarbonate and Tempered Glass. From an injury standpoint, the three most common areas associated with glazing are laceration potential, impact injuries, and ejection. This project focused on these three areas. For the most part, the evaluation of the glazing performance with respect to these areas is direct and the techniques used for assessing these injuries is accepted by the safety industry. The difficulties arise when considering the relationship between impact injury and ejection. When considering overall safety, if there is glazing breakage, then there is higher potential for occupant ejection. Conversely, if there is not glazing breakage, then the potential for occupant ejection is eliminated (at least through the glazing), yet the injury potential due to glazing impact is increases. The issue arises as to how the injury due to the glazing impact compares to the injury potential when there is a partial or full ejection. Whenever there is an ejection of any kind, the range of objects that an occupant can strike is quite substantial and difficult to measure in laboratory testing. Therefore, one must carefully evaluate all potential and/or avoided injuries when considering the overall safety provided by one particular form of glazing compared to another. In order to set the stage for the rest of the paper, it is important to briefly define a few terms as they are used here. A ?쏱rimary??impact is defined here as when there is direct glazing contact between the occupant and glazing.?쏶econdary??impact is defined as any occupant impact that is only possible when there is glazing breakage. The testing results revealed a number of significant trends. Based on the tests conducted in this study, the Polycarbonate glazing did not result in any major fractures due to the initial impact event in any of the test cases. Secondly, based on the testing, it has been shown that the impact injury potential of the Polycarbonate glazing appears to be no greater than other interior components of the vehicle. This is based upon film and data analysis in which contact between the occupant and glazing and other surfaces was studied. Overall, the results of this testing indicate that there does not appear to be an added safety risk with Polycarbonate glazing when all the facets of occupant injury potential are considered, and, in addition, there may be a significant safety benefit in the form of occupant ejection containment. |
Locking Actuators Today and Beyond | Hydraulic actuators with internal mechanical locks are attractive when safe repeatable positioning is required along with insensitivity to load and hydraulic pressure variations. Internal locking designs generally offer a lighter, smaller, better protected solution than external locks for applications such as: landing gear, doors, highlift devices, inlet/exhaust geometry control, and armament positioning. The evolution of higher pressure hydraulic systems imposes design challenges because of smaller areas, higher stresses, and high release loads. This paper looks at the experience of one supplier of locking actuators, Dowty Decoto, Inc. (DDI), and at the technology that is, and will be, required to provide the industry with functional, reliable locking actuators. |
A Consideration Of Wind Noise Reduction By Air Flow Control | The relation between the wind noise level at high speed cruising and the vehicle body shape was studied. The wind noise level in the vehicle depends on the external aerodynamic noise and the noise isolation characteristic of the weatherstrip, body panel and so on. In order to reduce the wind noise level; the modification of the body shape is an important Batter. Based on model experiments, it is shown that the aerodynamic noise is generated mainly on the front door windshield glass and its level is effected by the air flow around front pillar. As the aerodynamic noise is induced by the velocity or pressure fluctuation of air flow, the relationships among the front body shape, the air flow fluctuation and the aerodynamic noise are described analytically. The results were applied to the improvement of design of the production vehicles. |
Evaluation of Composite Components on the Bell 206L and Sikorsky S-76 Helicopter | Progress on two programs to evaluate structural composite components in flight service on Bell 206L and Sikorsky S-76 commercial helicopters is described. Forty ship sets of composite components that include the litter door, baggage door, forward fairing, and vertical fin have been installed on Bell Model 206L helicopters that are operating in widely different climates. Component installation started in 1981 and selected components are being removed and tested at prescribed intervals over a 10-year evaluation. Four horizontal stabilizers and ten tail rotor spars that are production components on the S-76 helicopter are being tested after prescribed periods of service to determine the effects of the operating environment on their performance. Concurrent with the flight evaluation, materials used to fabricate the components are being exposed in ground racks and tested at specified intervals to determine the effects of outdoor environments. In this paper, results achieved from 73,000 hours of accumulated service on the 206L components and 50,000 hours on the S-76 components are reported. Six ship sets of 206L components have been removed and tested. Results of 5 years of ground exposure of materials used to fabricate the 206L components are presented. Results of tests on three S-76 horizontal stabilizers and seven tail rotor spars are presented. Panels of material used to fabricate the S-76 components that were exposed for 4 years have been tested and results are presented. |
Automotive Mini Disc Changer Mechanism | A new automotive Mini Disc (MD) changer mechanism has been developed which fits a 1 DIN size chassis. This mechanism, mainly consisting of a disc change mechanism and an anti-vibration mechanism employing a floating disc drive unit system, offers a high vibration resistance, quick disc change capability and a size small enough to set a unit in an instrumental panel (I/P). |
ITS, A New Restraint System for Side Impact Protection | The Inflatable Tubular Structure (ITS) is a safety system intended to provide head protection during side-impact car accidents. The ITS is an inflatable device fixed at two points; at the front end, to the A-pillar, and at the aft end, to the roof rail behind the B-pillar. It is stowed over the side window under the trim of the A-pillar and the headliner. At one end, a gas generator is electrically connected to the side-impact crash-sensing system which inflates the ITS when needed. The ITS is fabricated in a unique way so that, upon inflation, its diameter greatly increases and its length correspondingly decreases. This causes the ITS to pull itself out of its stored location over the side window into a straight line between its anchor points. The ITS thereby forms a taut semi-rigid structural member across the window opening. The ITS is brought to a pressure higher than an air bag, and is unvented so that, even upon the cooling of the gas, it retains its position independent of window glass support to provide protection in secondary collisions and rollovers. |
Study of Whistles with a Generic Sidebranch | The coupling of shear layer instabilities with the acoustic resonances at the interface of two ducts, a main duct and a connecting sidebranch, leads to whistle noise. The present study investigates experimentally the mechanism of such pure tone noise. A generic sidebranch adapter is fabricated to allow for: (1) the ability to mount downstream of the throttle body in the induction system of a production engine; (2) the adjustment of sidebranch length; and (3) the changes in the diameter of the branch duct. Experiments are conducted both in a flow facility and an engine dynamometer facility for the same set of flow rates. The correlation of the whistle noise between these two facilities is examined in terms of frequency and the dimensionless numbers, including Strouhal and Mach. |
Adaptive Camouflage | Lightweight optoelectronic systems built around advanced image sensors and display panels have been proposed for making selected objects appear nearly transparent and thus effectively invisible. These systems are denoted "adaptive camouflage" because unlike traditional camouflage, they would generate displays that would change in response to changing scenes and lighting conditions. |
E-BEAM Treatment of Organically Contaminated Water | Energetic electrons injected into water abundantly create short-lived radicals that initiate rapid reactions. This leads to the break-up of organic contaminants into harmless products. The process works without catalyst (or other consumables) at ambient temperature and pressure. It is highly energy-efficient. We discuss preliminary results concerning removal of trichloro-ethylene, chloroform, benzene, and toluene using an electron beam (E-BEAM) system. On the basis of these results, we review the development of a compact E-BEAM system that can be used in space inhabitation and long-term space travel. Portability is achieved by using a relatively low beam energy, ~250 keV. We discuss newly available electron transparent windows, the development of a high-efficiency accelerator and power supply that control the power consumption to a level acceptable by NASA standards. |
A Semi-Empirical Approach for Modeling Greenhouse Surface Wind Noise | A CAE procedure for modeling the aerodynamic excitation of greenhouse surface vibration and its reradiation as noise is described. The procedure begins with a description of the steady flow over the surfaces. This is used as a basis for estimating the spatially varying unsteady pressure loading. The approach is semi-empirical, utilizing normalized pressure data collected through wind tunnel testing of production vehicles. The unsteady pressures are utilized within a normal mode analysis to predict vibration of the greenhouse panels. Interior noise associated with the panel vibration is estimated from a statistical energy analysis model. We show that contributions of multiple surfaces can be significant. |
Booming Noise Analysis in a Passenger Car Using a Hybrid-Integrated Approach | A hybrid-integrated approach is presented to analyze the structure-borne booming noise in a passenger car. We identify the critical noise transfer path from the engine to the target by the transfer path analysis. However, it does not give the answer for why the noise transfer function is so high at that path. Therefore, an integrated approach which applies the analysis tools systematically is presented. The running mode analysis gives us the operating motion of each component in the body structure. However, there is no evidence that the components that vibrate severely are the sources of this problem. The modal characteristics from the structural modal test enable us to describe the real motion of the body completely in terms of the structural modes. Similarly, the acoustic modal characteristics from the acoustic modal analysis describe the fundamental behavior of the cabin cavity. The introduction of the experimental running mode data of the structure to the acoustic finite element model makes the hybrid analysis possible. Through the structural and the acoustic modal analysis, we verify the mode that contributes to the booming noise. The panel contribution analysis points out the components that have the greatest influence on the booming noise. The modification of the body based on the results of the hybrid-integrated approach results in the great decrease of the noise level. |
Development of Vehicle Underbody Acoustic Holography | Acoustic holography is adopted in identifying the noise sources of a vehicle's underbody. Wind noise from a vehicle's underbody accounts for a large portion of the overall noise level due to the complex flow structure. Current study presents the development process of acoustic holography in the vehicle underbody. Difficulties associated with using acoustic holography as well as the method to eliminate the effect of sound reflection will be addressed. |
Experimental and Hybrid Modeling of the Medium Frequency Behaviour of Car Panels | This paper discusses an approach to identify critical car panels and to derive detailed experimental models for these critical panels. The research was conducted in the framework of the Brite/Euram project SALOME and the EUREKA project HOLOMODAL. The panel identification method is based on a numerical or experimental contribution analysis, assessing the partial noise contributions of individual panels to the interior noise. The second step in the approach consists of the derivation of detailed modal analysis models for the critical panels. A novel Electronic Speckle Pattern Interferometry (ESPI) system was developed, and integrated in a classical CAE system. The components of this system are briefly reviewed, and their application to several industrial cases is shown. |
Plastic Product Implementaion into Production -Steps from Concepts to Production Reality | The high temperatures associated with paint curing of automobiles fenders causes dimensional variation at the door and hood areas. This paper details the experimental techniques used to study the dimensional changes in fenders after they are processed and assembled ?쐎nline?? Specific dimensional changes are presented and recommendations for computer-aided -engineering predictions are enumerated. Current work to reduce dimensional variations is described. |
Evaluation Methodologies for Automobile Side Impact Development | A comprehensive strategy for applying quasi-static and dynamic tests in the development of automobile side impact protection systems is presented. The approach is geared towards providing an understanding of how vehicle components relate to occupant protection as measured by the FMVSS 214 dynamic side impact test. These test methods are viewed as being complimentary, rather than competitive, tools to be employed in the overall strategy. The approach begins with obtaining detailed data from an FMVSS 214 dynamic test. Additional instrumentation is required so that the results of the test can be used to form the basis for setting conditions for subsequent quasi-static and dynamic tests. The Composite Test Procedure (CTP) is an integral part of the process. As described here, the CTP can be conducted under three different methods; three step procedure, continuous computer control, and continuous manual control. The principal value of the CTP method is to obtain spatial relationships within the door structure, overall force-deflection properties of the vehicle body structure, and input for a simplified, linear spring mass model to represent the FMVSS 214 dynamic test. Door structures are tested to provide a preliminary evaluation of door modifications, including both structure and trim panel, without resorting to full vehicle body development and build. The methods for door tests include both quasi-static, where the door structure and trim panel are evaluated, and dynamic (sled), where door trim panels are evaluated. Results obtained from these component tests can be related to full scale crash testing through mathematical modelling. The complimentary nature of these test methods is then discussed relative to improving performance in an FMVSS 214 dynamic test. A flow chart showing the relationship to a complete vehicle development program is presented and discussed. |
Transient Vibration Analysis During the Door Closing by Using the Laser Holography Method | The door closing sound is one of the important quality of a vehicle, and it is useful to study the improvement method of closing sound. As a step to clarify the relationship between the door structure and closing sound, it is attempted to correlate the formation of closing sound with the vibration, and explained that the effect of structural modification aimed to improve the closing sound from the viewpoint of vibration. First, the formation process of the vibration during the door closing is clarified through the analysis method of transient vibration using the pulse laser holography. And the quality of closing sound are evaluated based on the time historical fluctuation of frequency characteristics. Next, the correlation between the closing vibration and sound are studied, and for the case of that the closing sound are changed by the structural modification, the correlation are confirmed. |
The Corrosion Resistance of Organic Composite-Coated Steel Sheets | In order to investigate the corrosion resistance of organic composite-coated steel sheets ( OCS ) in a real automotive environment, many kinds of corrosion tests were performed on test pieces and real automotive doors. Tests with a corrosive solution including iron rust were introduced to simulate the real corrosive environment of automotive doors. The relationship between the components of OCS and the corrosion resistance in the rust-including tests was examined. In addition, electrochemical studies were performed. Results indicate OCS has much better corrosion resistance than plated steel sheets with heavier coating weight in all tests. OCS shows excellent corrosion resistance in rust-free corrosive solution, however, some types of OCS do have corrosion concerns in rust-including tests. It became clear that these OCS types have an organic coating with lower cross-linking. With respect to the components of lower cross-linking OCS, Chromate coating has little effect on corrosion resistance in rust-including solution. On the other hand, an organic coating with higher cross-linking shows remarkable improvement of corrosion resistance in rust-including test solutions. Therefore, it is likely that thin organic coatings are susceptible to damage by rust including test solution. Electrochemical measurement actually shows that impedance of OCS after exposing in rust-including solution is lower than before exposing. Consequently, the rust-including tests did simulate the real automotive corrosive environment. It is important to use a proper organic coating with high resistance against rust, because rust exists in real automotive corrosive environments. |
Perforation Corrosion of Automobiles - Field Car and Laboratory Investigation | In order to clarify the effect of design and materials of the hem as well as the climatic factors on perforation corrosion of the automobile doors, field car and laboratory investigation has been carried out Field car investigation revealed that corrosion of the hem can be minimized by using two side galvanized steel plus adhesives. The ratio of wet/dry environment was evaluated in laboratory on hemmed sample, and it was found that the design of the hem in conjunction with the various wet/dry ratio affected the corrosion rate differently. |
Flexvalve: An Innovation in Air Flow Control | This paper describes a flexible-film bladder, mode door. An air line is attached directly to the flexible valve through the mode housing or air duct for vacuum or positive pressure actuation. This technology addresses the need for more compact designs, part reduction and weight savings. It is designed to replace current mode valve doors, actuators and associated brackets. The propounded benefits of this design are outlined along with design considerations and part/system validation testing. |
Estimation of the Noise and Vibration Response in a Tractor Cabin Using Statistical Energy Analysis | The purpose of this paper is to establish a method of predicting the noise and vibration of tractor cabins in the engine-idling state by using Statistical Energy Analysis (SEA). At first, an analytical model of a tractor cabin is constructed, and power flow equations are formulated for the tractor cabin. To solve these equations, SEA parameters are estimated experimentally and analytically. These parameters are the modal density, loss factor, coupling loss factor, and input power. With these parameters, the noise and vibration responses of the tractor cabin are calculated. Good agreements are found between the analytical and experimental data. |
Maturing Fiber Reinforced Thermoplastic Technology for Automobile Body Structural Applications | With the increasing emphasis on fuel efficiency and environmentally friendly vehicles, much effort is being directed by the auto industry to develop efficient, lightweight and alternative-powered vehicles. One of the ongoing research programs at DaimlerChrysler's Liberty and Technical Affairs is not only aimed at reducing the overall weight of the automobile body structure, but also reducing the cost of manufacturing it. In addition, an automobile body structure needs to meet the requirements of noise, vibration and harshness (NVH), durability, crashworthiness and recyclability. The objective of this paper is to provide a review of the ongoing research and development activities leading to an automobile body structure that meets the above objectives. The paper highlights the many different technology development challenges faced during the process. Discussions of the choice of material systems, injection molding of very large body structural panels using these material systems, their applications to different products, cost implications and supplier issues are included in this paper. |
Rapid Development and Deployment of Dynamic Graphical Human-Machine Interfaces Within Automotive Environments | Emerging ?쁤lass??displays make possible the benefits of Super Integration (SI) including weight, volume, and part count reductions as well as quality, reliability, serviceability, NVH, and manufacturability improvements [1]. This paper discusses an alternative to the hand-coding of displays aimed at facilitating the iterative development of Human-Machine Interfaces (HMIs) and the rapid generation of small-footprint, high-performance embeddable code for use in development, testing, simulation, documentation, and actual product environments. The process of code generation and rehosting at the heart of this technology will be described as will the architecture of the resulting software. Implementation experience will also be cited. |
Optimizing Sensor and Actuator Arrays for ASAC Noise Control | This paper summarizes the development of an approach to optimizing the locations for arrays of sensors and actuators in active noise control systems. A type of directed combinatorial search, called Tabu Search, is used to select an optimal configuration from a much larger set of candidate locations. The benefit of using an optimized set is demonstrated. The importance of limiting actuator forces to realistic levels when evaluating the cost function is discussed. Results of flight testing an optimized system are presented. Although the technique has been applied primarily to Active Structural Acoustic Control systems, it can be adapted for use in other active noise control implementations. |
Intrusion Resistance Test Development for Automotive Glazing | Consumers worldwide are demanding intrusion resistant automotive glazing. In response, carmakers are installing laminated side and rear glazing for enhanced protection. To insure enhanced protective glass (EPG) performance, a test is being developed to measure intrusion resistance in three simulated break-in modes. The three test modes are: glazing point attack; exterior impacts to penetrate the glazing or separate it from the vehicle body; continuous force to pull the glazing out of the body. The strength of the glazing and the strength of the glazing/vehicle attachment are both important for intrusion resistance. An intrusion resistance test method is recommended. |
Establishment of Stamping Process Windows | A stamping process window is a set of ranges of the critical input variables in the process. Quality parts can be produced only if all of these variables fall within their respective ranges. To achieve this, the window has to be wide enough and the process properly located within the window. In this paper, various input variables in stamping are examined and the variables that have to be strictly controlled are identified. The establishment, transfer, adjustment, protection, deterioration and re-opening of stamping process windows are described. Examples from production are presented. |
Measurement and Evaluation of Aerodynamic Noise | Recently, aerodynamic noise which originates in the flow of the body surroundings is actualized as a main cause of an automobile interior noise when running at high speed, because engine, power train and tire noise have been greatly decreased. Along with it, the measurement technology for the phenomenon elucidation and the evaluation has been demanded to decrease aerodynamic noise. In this paper, typical measurement examples of aerodynamic noise are introduced. These measurement technologies can be classified, and arranged to four types of measurements, which are flow, external noise, transmission psth and interior noise. This paper presents how the advancement of these measurement technologies has contributed to the aerodynamic noise elucidation. Moreover, the latest evaluation method of aerodynamic noise and the trend in the future to the demand of customer's many topics are introduced. |
Review of Aerodynamic Noise Prediction Using CFD | Recently, computational fluid dynamics (CFD) has made great progress. This paper reviews published papers on aerodynamic noise simulated by CFD and studies to what level CFD can predict aerodynamic noise for basic models and for applied models of automobiles. Based on noise generation mechanisms, aerodynamic noise is basically classified into two types, that is, noise induced by two-dimensional flow and by three-dimensional flow. As typical examples of noise generated by two-dimensional flow, wind throb at opened sliding roof, edge tone at the end of liftgate and aeolian tone generated by a cylindrical antenna are simulated by several computational schemes. As typical examples of three-dimensional flow, noise generated by A-pillar longitudinal vortex and noise from a side view mirror are computed by using a wing model and a actual vehicle, respectively. Noise by two-dimensional flow can be almost estimated whereas noise by three-dimensional flow cannot be predicted at sufficient accuracy especially in high frequency range. In order to predict noise with high accuracy it is necessary to improve computational techniques, based on noise data obtained by a carefully conducted wind-tunnel experiment which studies basic flow patterns with simple models. |
Life-Cycle Optimization of Car Components | The environmental impact of the automobile and its components is of growing importance not only in public debates but also in the complex decision making process regarding future car concepts. To calculate the environmental compatibility of car components BMW has developed various quantifying instruments and a holistic Life-Cycle Analysis (LCA) approach. The development phase significantly affects the entire life-cycle of a product. Suitable design criteria, recycling requirements and in-house standards have therefore been developed and established. One of the most important objectives in optimizing the environmental compatibility of the automobile is the realization of intelligent lightweight concepts. This means one has to find the most appropriate solution in terms of ecology and economy. Due to modern development processes car manufacturers and their suppliers have to intensify their cooperation also in this area. This paper presents some results of the cooperation between BMW and Hydro Aluminium for optimizing the life-cycle of various lightweight door concepts. Some general conclusions and ?엓ightweight laws??have been deduced therefrom. This integrated life - cycle approach on a component base has the potential to become a practical development tool for managing the additional conflict of objectives with a view to the life-cycle ecology and economy of the automobile. |
Low Frequency Design Considerations for Automotive Audio Systems | The automobile interior is a challenging environment for the audio system designer. Yet, the literature related to automotive acoustics is sparse compared to the amount of published information on the acoustics of rooms and performance spaces. This paper addresses three areas of importance to the design of high fidelity autosound systems. First, it is difficult to accurately predict the nature of the listening acoustics in a car at low frequencies because complex interior geometries make mode calculations almost impossible. At the same time, the cabin interior introduces acoustic gain in the first three octaves of musical reproduction. Secondly, the car environment is subject to constantly changing levels of so-called road noise that mask musical material at low frequencies. Finally, a simplified model is proposed for the characterization of the car door as a loudspeaker enclosure. Measurement data are presented to illustrate the nature of low frequency gain in automobile cabins and to evaluate the feasibility of the proposed enclosure model. |
High Performance Executive Transport Design Employing Twin Oblique Lifting Surfaces | This paper presents a new Trans-Atlantic high performance executive transport suitability equipped to offer accommodation for 19 first class passengers. The unique feature of this conceptual design is application of Twin Oblique Lifting Surfaces or TOLS configuration. Minimum goals for the design included: similar maximum takeoff gross weight; satisfactory field performance; good stalling characteristics; and, competitive fuel burn qualities at high-transonic and low-supersonic speeds, i.e. M0.90??.20, compared to contemporary M0.75??.85 large and super-large business jets. The vehicle is to be powered by two medium by-pass derivative engines based on the BMW-Rolls Royce BR715 in an effort to maximize the likelihood of availability, ensure adequate en route performance efficiency and fulfillment of yet to be ratified Stage 4 noise compliance requirements. |
Assessment of a Vehicle Concept Finite-Element Model for Predicting Structural Vibration | A vehicle concept finite-element model is experimentally assessed for predicting structural vibration to 50 Hz. The vehicle concept model represents the body structure with a coarse mesh of plate and beam elements, while the suspension and powertrain are modeled with a coarse mesh of rigid-links, beams, and lumped mass, damping, and stiffness elements. Comparisons are made between the predicted and measured frequency-response-functions (FRFs) and modes of (a) the body-in-white, (b) the trimmed body, and (c) the full vehicle. For the full vehicle, the comparisons are with a comprehensive set of measured FRFs from 63 tests of nominally identical vehicles that demonstrate the vehicle-to-vehicle variability of the measured FRF response. |
A Method and Apparatus for Generating Full Vehicle Roof System Rain Noise for the Purpose of Development, Benchmarking and Interior Noise Performance Measurement | The direct excitation of a vehicle roof system by a repeatable method and the corresponding interior sound pressure level generated by that excitation can be a key characteristic of the total interior acoustic signature of a vehicle. After nine years of work and five design iterations, a test method and apparatus has been developed that exposes a vehicle to a repeatable and measurable artificial rain excitation. The test apparatus, method and performance data are reviewed. Performance data is shown for several different vehicles and roof systems. |
Feasibility of Using Acoustic Room Models and Measured Sound Power to Estimate Vehicle Interior Noise | In this paper, interior noise of a heavy commercial truck was modeled with the room equation. This approach assumed that large truck cabins may be adequately modeled as a practical room as is done in architectural acoustics, where ray theory and statistical concepts are suitable, and where application of complicated wave theory may not be necessary. This simplifies computational requirements, making a semi-empirical scheme useful for timely product development. This study employed sound power measurements at thirty-four surface patches encompassing the interior cabin boundary. Each surface-patch constituted an individual interior noise source. Predicted and measured results correlated well, demonstrating the capability to estimate driver-position noise level from predicted periphery sound intensity changes. |
New Developments on Glazings | Increase of size and bending of glazings, and general improvements concerning NVH, has made of glazings one of the weak points to be treated. No specific acoustic solutions existed. First question was to determine exactly concerning which problems glazings were involved, and then what and how solutions could be found. Main problems were found concerning booming noise, transmission of airborne external noise and aerodynamic noise. To dispose of good specifications concerning products, simulations had to be done and validated: finite elements code for low frequency behavior (booming and airborne), SEA and modal superposition concerning medium and high frequency (aerodynamic and airborne). This was done for monolithic and laminated glass with their shape, free-free and taking into account boundary conditions: glues, extrusion, encapsulation. The way it has been done is presented: measurements of the characteristics of components (interlayers, glues), use of FEM and FEM-BEM methods from CAD shapes, use of SEA. Validations are also presented. Problems to solve were mostly coupling between windshield eigenmodes and internal modes of the cavity excited by the engine (low frequency), and whistling due to coincidence frequency of glass concerning mostly aerodynamic noise. Solutions are found by using specific interlayer instead of standard PVB within the laminated glass, or by improving boundary conditions by using specific shapes and/or material of the joint, first defined by a specific software. Psychoacoustic criteria are used to optimize the solutions. Shape influence is also studied. Some specific studies concerning both problems are presented. Some glass solutions now exist to reduce NVH problems within cars, and/or to compensate reduction of weight, which is one main topic of car industry. |
Noise and Vibration Reduction Technology in Hybrid Vehicle Development | The world's first mass production gasoline hybrid passenger car, the ?쏱rius?? was introduced into the Japanese market in 1997. By the time it was introduced into the American and European markets in Mid-2000, its fuel consumption and exhaust emissions had been further improved while achieving superior NV performance compared with conventional vehicles with 1.5-liter engines even in these competitive markets. This paper describes NV reduction technology for problems peculiar to the hybrid vehicle such as engine start/stop vibration, drone noise and vibration at low engine speed and motor/generator noise and vibration. It also compares the overall NV performance of the hybrid vehicle with conventional gasoline engine vehicles. |
Automatic Detection of Buzz, Squeak and Rattle Events | In the world of BSR (Buzz, Squeak and Rattle) testing, there is a high level of sophistication regarding the test machines employed to excite the items under test as well as the techniques used to ensure that the test is representative of real-life operating conditions. However, the object of the measurements, i.e., the identification of transient acoustic events classified as Buzz, Squeak or Rattle, is mostly a subjective procedure with classification in terms of Sound Pressure Level in dB(A) or Stationary Loudness. These ?쐓tandard??metrics have proven, in general, unreliable in assessing the importance of individual transient events, and inappropriate to describe the vehicle signature from a BSR standpoint. This paper presents a methodology that has been developed for the BSR test of a vehicle using a road simulator to: 1 Demonstrate the feasibility of an automated system of detection of BSR events that can replace the ?쐓ubjective??detection 2 To establish ?쐖ehicle BSR??indices that can be used to assess design targets and specifications. |
Vehicle Wind Noise Analysis Using a SEA Model with Measured Source Levels | A series of tests have been performed on a production vehicle to determine the characteristics of the external turbulent flow field in wind tunnel and road conditions. Empirical formulas are developed to use the measured data as source levels for a Statistical Energy Analysis (SEA) model of the vehicle structural and acoustical responses. Exterior turbulent flow and acoustical subsystems are used to receive power from the source excitations. This allows for both the magnitudes and wavelengths of the exterior excitations to be taken into account - a necessary condition for consistently accurate results. Comparisons of measured and calculated interior sound levels show good correlation. |
Condition Monitoring of a Gear Box Using Vibration and Acoustic Emission Based Artificial Neural Network | The objective of this study is to investigate and develop an Artificial Neural Network approach based on vibration and AE signals for the detection, and characterization of wear, damage, and malfunction of an experimental gearbox. Five artificial defects were introduced to the gearbox and these are; (1) tooth face wear, (2) full tooth breakage (missing tooth), (3) clearance or backlash, (5) axial gear looseness, and (5) single internal bearing race wear. The signals, collected from extensive experimentation, were analyzed using time-frequency harmonic wavelet transform, Power Spectral Density (PSD), and four statistical measures of the time domain that captured the salient features of the vibration and AE signals. The results of the time and frequency domain analysis were used in developing a neural network-based estimator for on-line monitoring of gearbox operational condition. The results strongly suggest that vibration and acoustic emission (AE) signals have tremendous promise for machine health monitoring and diagnostics. The proposed technique can be adopted for on-line monitoring of power train and Engine systems, which could be a second phase of this project. |
A Comparison of NVH Treatments for Vehicle Floorpan Applications | Under the constraints of improved vehicle refinement, automotive OEMs are challenged to improve vehicle noise, vibration and harshness (NVH) characteristics, reduce vehicle weight, and streamline manufacturing and assembly processes. In support of these objectives, alternate methods of vehicle noise control are being investigated. This paper will address one area where alternate material strategies are being investigated to meet these requirements. Floorpan damping treatments are a primary component of the overall vehicle noise package. This paper will investigate three floorpan damping treatments. Comparisons will be made between asphaltic melt sheets, constrained layer dampers, and spray-on dampers. Performance of these treatments will be measured using laboratory methods and will feature a case study using a Body-In-White (BIW) to demonstrate performance of the different materials. |
The Application of Direct Body Excitation Toward Developing a Full Vehicle Objective Squeak and Rattle Metric | In order to engineer Squeak & Rattle (S&R) free vehicles it is essential to develop an objective measurement method to compare and correlate with customer satisfaction and subjective S&R assessments. Three methods for exciting S&Rs -type surfaces. Excitation methods evaluated were road tests over S&R surfaces, road simulators, and direct body excitation (DBE). The principle of DBE involves using electromagnetic shakers to induce controlled, road-measured vibration into the body, bypassing the tire patch and suspension. DBE is a promising technology for making objective measurements because it is extremely quiet (test equipment noise does not mask S&Rs), while meeting other project goals. While DBE is limited in exposing S&Rs caused by body twist and suspension noises, advantages include higher frequency energy owing to electro-dynamic shakers, continuous random excitation, lower capital cost, mobility, and safety. Results show that almost all S&R issues found on the road and simulator are found on DBE. In many cases additional issues are discovered because of the lack of background noise. Initial data tends to show that using DBE to excite interior S&Rs is preferable to actual roads or to 4-post road simulators for making objective measurements. |
Use of Layered Media for Noise Abatement in Automotive Interiors: A Balanced Approach | Concepts for dual density materials for usage as absorbers and decouplers are based on well-established layered media principles and have been applied for many years in non-automotive applications. Balancing the mass, air flow resistance, and thickness allows for improved noise attenuation in the low to mid frequency range which is of particular interest for automotive NVH management. Using these principles, products were tuned via mass and airflow resistance to reduce noise levels while also significantly reducing mass. Validation in various vehicles confirmed that up to a 55% reduction of a sound package's mass is possible. The considerable weight reductions of dash insulators and carpet systems are possible at the same times as the sound level in the vehicle interior is at least maintained and frequently improved. Product designs utilize non-woven fabrics and vertically and or horizontally lapped fibers to provide excellent fit and finish at low weight in an all-thermoplastic, recyclable product. Here, product development is described, which utilized computer modeling to provide a balance between transmission loss and absorption properties. Test results showing the effects of various properties on sound transmission loss and normal incidence absorption as well as in vehicle performance are given. |
?쏡igital Prototype??Simulations to Achieve Vehicle Level NVH Targets in the Presence of Uncertainties | ?쏡igital Prototype??simulations have been used at DaimlerChrysler to achieve vehicle level NVH objectives. The effectiveness of these simulations to guide the design when faced with vehicle parameter uncertainties is discussed. These uncertainties include, but are not limited to, material properties, material gauges, damping, structural geometry, loads, boundary conditions and weld integrity. Manufacturing and assembly processes introduce variations in the nominal values of these parameters resulting in a scatter of vehicle level NVH simulation responses. An example of a high frequency NVH concern will be studied and modified to arrive at robust design guidance when faced with uncertainty. The validity of a ?쐂eterministic digital prototype??simulation model and its relevant role as a ?쐔rend predictor??rather than ?쏿bsolute predictor??tool in guiding the design is also discussed. |
Development and Experimental Evaluation of a Vehicle Structural-Acoustic Trimmed-Body Model | A structural-acoustic finite-element model of an automobile trimmed-body is developed and experimentally evaluated for predicting body vibration and interior noise for frequencies up to 200 Hz. The structural-acoustic model is developed by coupling finite element models of trimmed-body structure and the passenger-compartment acoustic cavity. Frequency-response-function measurements of the structural vibration and interior acoustic response for shaker excitation of a trimmed body are used to assess the accuracy of the structural-acoustic model. |
Active Noise Control and Sound Quality Design in Motor Vehicles | Interior noise in motor vehicles is essentially influenced by the engine which may contribute via both, structural and acoustic transmission paths. This engine related interior noise components may be controlled deliberately by active control measures without changing any source or transfer paths characteristics. Besides attenuating dominant noise components, the approach may equally be used to optimise interior sounds with respect to sound quality. Based on general considerations how active noise and vibration control measures may effect subjective criteria, the paper gives examples how different, sometimes extremely contrasting noise characteristics may be realised in a given car. |
Safety Related Testing and Results of Polycarbonate and Tempered Glass Non-Windshield Glazing Applications | This paper presents results from a series of tests that address safety related issues concerning vehicle glazing. These issues include occupant containment, head impact injury, neck injuries, fracture modes, and laceration. Component-level and full vehicle crash tests of standard and polycarbonate non-windshield glazing were conducted. The tests were conducted as part of a study to demonstrate that there is no decrease in the safety benefits offered by polycarbonate glazing when compared to current glazing. Readers of this paper will gain a broader understanding of the tests that are typically conducted for glazing evaluation from a safety perspective, as well as gain insight into the meaning of the results. |
Package Tray Optimization Using Experimental and Analytical Techniques | The area in the neighborhood of the package tray can be a significant path for road noise and exhaust noise. Air extraction routes and loudspeakers add to the difficulty of effective system design. A variety of designs were prototyped and their transmission loss measured in a standard SAE J1400 sound transmission loss suite. The performance of the various designs was compared to an untrimmed piece of sheet metal with embedded air extraction holes. The addition of trim added from 1 dB to 14 dB to the transmission loss. Statistical energy analysis (SEA) models of a variety of package tray systems will also be shown. Both of these techniques can provide design guidance at an early stage of vehicle program development. |
THE WINDOWBAG: AN INNOVATION IN SIDE IMPACT PROTECTION | A new additional airbag system will provide enhanced protection in side impact collisions. The so - called Window Bag will be installed in some Mercedes cars beginning with the E-Class Sedan for the MY99 and in the new S - Class. |
Dispelling the Misconceptions about Side Impact Protection | Those responsible for designing cars to meet the European Side Impact Test Procedure are tending to find it more difficult than they originally expected. The conventional wisdom has been that strengthening the car and providing padding should improve protection. However, many are finding that attempts to meet the test requirements, by reducing door intrusion or intrusion velocity, are proving ineffective. Extensive research carried out at TRL has helped to explain why strengthening the car side is ineffective. It has also given an insight into the side impact injury process and provided design guidelines which can be used to ensure that cars meet the test requirements. The difficulties experienced by car designers may explain why alternative test procedures have been suggested and proposals have been made which would reduce the severity and effectiveness of the full scale test procedure. This paper reports on the extensive research carried out by TRL, explains why the conventional wisdom was flawed, details the design guidelines and provides reasons why the beneficial use of quasi-static and component testing of doors is likely to be limited. |
The Application of the Simulation Techniques to Reduce the Noise and Vibration in Vehicle Development | An overview of the analytical noise and vibration simulations performed to support the design and development of the passenger car was presented. Analytical models of the structural vehicle and acoustic cavity were developed, and several simulations related to the NVH were performed in the prototype development stage. All of the simulations were performed to minimize development time as well as to optimize the cost, weight, and performance of the NVH and the maximum frequency of these analyses is 200 Hz. The modal analysis and design sensitivity analysis of the body-in-white was performed to minimize the mass while maintaining the body stiffness by using the concept model and detailed model. Most of the subsystems such as engine mount, steering, suspension and exhaust pipe system were analyzed respectively and in the combined system for the design studies of the idle shake and high-speed wheel shake analysis. Structure-borne noise due to both road-induced vibration and engine vibration were considered. Most of the analysis was performed before prototype vehicles were tested to make the design implementation. The vehicle design cycle was reduced and the noise and vibration quality was improved by application of these simulations. |
CUPOLA Environmental Control System | The Cupola Environmental Control System (ECS) has the task to ensure the required Cupola internal environment using passive and active control means, in response to the relevant applicable Cupola requirements. The ECS is subdivided into a Thermal Control Subsystem (TCS) and an Environmental & Life Control Subsystem (ECLS). The particular characteristics of Cupola design requires a non standard way to control the internal environment conditions: TCS controls the Cupola primary structures through an High Temperature water Loop (HTL) avoiding shell heaters necessity in the cold cases and representing also an heat sink for the windows assy in the hot cases; ECLS design realizes the air distribution inside the cabin volume using the gap existing between the primary and secondary structure without dedicated ducts. The major ECS functions are: to control the primary and secondary structure temperatures, to homogenize the structural walls temperature using the HTL, to prevent the condensate formation inside the Cupola, to control the Cupola Internal Pressure, to guarantee a fire protection inside Cupola, to define an air distribution concept, to support a safe, habitable, shirtsleeve environment inside the Cupola. The paper describes also the extensive analysis campaign planned to support the Cupola TCS and ECLS design and verification phases. |
Subcompact Sport Vehicle Development | Considering that the sport cars versions are normally derived from medium car segment, the big challenge in this program was to transform one subcompact in a real sport car. With the focus at the consumer that looks for performance and enjoys sporty driving in conjunction with project financials and competition data the preliminary content was established together with all involved areas, Marketing, Finance, Manufacturing and Quality. Based on the items that indicate high performance, the items considered mandatory or desired by the customer and items detected by Quality research including internal indicators and external indicators, ICCD (Intensified Customer Concern Definition) and TGW (Things Going Wrong), the content was developed in three main directions towards Customer Satisfaction, I) Characterize the vehicle as a high performance car, a pure sport car with outstanding performance for power train, suspensions and brakes mainly. II) Identify the items considered mandatory by the customer for a sport car, for example. Alloy wheels, low profile tires, spoiler and rocker panel cladding, etc. III) Incorporate Quality and Durability improvements at modified or new systems. As part of the actions included at content the project objectives were established for Performance, Fuel Economy, Noise/Vibration/Harshness, Brakes, etc. These atributes was considered strategic for this product, a real sport car. With content preliminarily defined and the project strategy defined the development started with a timing plan defined with progressive phases until Job#1. The development phases consist in the verification and confirmation of product attributes with attribute and confirmation prototypes with durability and certification tests, resulting at engineering signoff and subsequent phases at production, with the 1st production prove out, and first field evaluation units and consequent production acceleration curve and the start of production. |
Comparison of Performance between Several Vehicle Windshield Defrosting and Demisting Mechanisms | The safety and comfort aspects of passenger cars are significant sales argument and have become a topic of rising importance during the development process of a new car. The objective of this study is to compare the performance of several current model vehicles, highlight the drawbacks of current defrosting/demisting systems and point the way to improved passive mechanisms. The investigation is experimental. The experiments are carried out using full-scale current vehicle models. The results show that the current designs of the defroster nozzle give maximum airflow rates in the vicinity of the lower part of the windshield, which decrease gradually towards the upper parts of the windshield. This hinders and limits the vision of the driver, particularly at the top of the windshield, which can be uncomfortable and indeed dangerous. |
Development and Application of an Integrated Dew Point and Glass Temperature Sensor | With the optimization of HVAC system controls for comfort, air quality and energy efficiency the potential for fogging the glass has increased. To maintain occupant safety, a method to predict when such fogging conditions exist is necessary to be able to execute proactive control corrections to prevent fogging. Windshield fog conditions are predicated on windshield surface temperature, cabin relative humidity and the reference temperature of the humidity sensor. This has driven a joint development project between Delphi Automotive Systems divisions to develop an Integrated Dew Point and Glass Temperature (IDGT) sensor. This sensor is a combination of three elements: a glass temperature sensor, a relative humidity sensor, and a humidity reference temperature sensor. Using this sensor package, the cabin dew point is calculated from the relative humidity and humidity reference temperature for comparison with the windshield glass temperature. When the windshield glass temperature drops to or is below the cabin dew point temperature, fog will form on the windshield. Utilizing this information, a proactive automatic climate control system implements corrections before the occurrence of fogging. This paper discusses the following issues concerning this new technology: Sensor design and development. A comparison between the existing technologies and the new sensor design. Vehicle / system integration of the sensor. |
Integration of Fluid Flow Modelling in the Vehicles Renault Development Process | This paper presents some of Renault's knowhow in modelling aerodynamic flows obtained in an operational environment on development configurations. The methodologies, developed from Navier Stokes equations averaged for turbulence, are used indeed to size openings and body elements, determine positions and optimize the geometry of the various air inlets and outlets, reduce pressure losses in the cab ventilation circuits, improve exchanger efficiency, optimize the underhood architecture devise encapsulation solutions, model windscreen de-icing, reduce aerodynamic noise and improve the understanding of certain physical processes associated with fouling. |
Conditions for Incipient Windshield Fogging and Anti-Fog Strategy for Automatic Climate Control | This paper describes a strategy, suitable for use in a climate control ATC (Automatic Temperature Controller) for predicting the onset or existence of fog (or misting) conditions and automatically taking action to avoid or reduce such conditions. Two variables currently measured by the ATC, cabin air temperature and ambient (outside) temperature are combined with cabin air relative humidity information provided by an additional sensor to allow the calculation of a degree of likelihood of windshield/window fogging. As fogging conditions are approached, a staged alteration of climate control strategy can relieve or even avoid altogether windshield fogging. |
42V Design Process | Demands for new features, increasing electrical loads, and improved fuel-economy are driving development of 42V PowerNets in automobiles. Shorter design cycles, increased complexity and a focus on quality are making robust design processes a strategic advantage for competitive manufacturers. Hardware prototypes are both time-consuming and inadequate for the task of verifying performance over a broad range of operating modes, environmental conditions and part-to-part variations. This paper outlines the use of an advanced design-flow, from idea to manufacturing, for vehicle power systems. It starts with the analysis of different topologies down to the subsystem modeling of a power window system. Finally it integrates everything to a Digital Mock-Up (DMU) and analysis of the entire system. Dynamic interactions among the various supplies, converters and loads are examined. System stability and performance are assessed under normal and extreme operating conditions. |
Automotive Glazing: Issues and Trends | Key current issues and future trends in automotive glazing were identified through extensive interviews of global OEM and supplier engineers. Although the performance of tempered glass has significantly improved, application of laminated glass to side and rear windows is expected to increase globally. Plastic, most notably polycarbonate (PC), glazing is also under development although the material technology has not reached a level for mass application. Incorporating multiple features and functions into glazing is another important technology development area. Needs and acceptance as to new materials and technologies vary by the automaker and the geographic market. |
Use of PVB in Laminated Side Glass for Passenger Vehicle Interior Noise Reduction | Polyvinyl butyral (PVB) is used in laminated side glass on several new vehicles. One of the major benefits of PVB-laminated side glass is the reduction of interior noise. To quantify this benefit, Solutia commissioned NVH testing of an S80짰 passenger car from Volvo with factory-equipped laminate side glass, comparing that with factory-equipped tempered glass. The noise source was a tractor-trailer truck traveling side-by-side with the vehicle. Significant noise reduction was noted (-2-6 dB in the 2k - 6k Hz range). The dampening characteristics of the PVB laminate interlayer reduced wind noise and greatly reduced traffic noise entering the cabin. A secondary benefit is that the NVH reduction was achieved while lowering the weight of the side glass by 11%. In this paper, results of the S80 vehicle testing will be reviewed and comparisons to conventional tempered glass shown. Also discussed will be OEMs, including Audi and Peugeot, which are marketing this benefit to customers. |
Comfort and Durability of Cabin of Commercial Vehicle | With the opening up of the economy and globalization in India, provision of reliable infrastructure has become a priority area in order to facilitate faster economic growth. The backbone for the economic growth is transportation. In transportation, the commercial vehicle industry plays a lion's role and hence demands urgent attention. One of the neglected areas in the commercial vehicles is its cabin. Driving commercial vehicle in India, is hard and hazardous work lasting for long hours in distant and unknown places of varying environmental conditions. In India, most often, the driver of a commercial vehicle is an employee unlike in developed countries where he is a owner driver. Further, most of the commercial vehicles supplied in India today are drive-away chassis and with the engine in the driver's compartment unlike the built-in cabins abroad. The design of the cab and the compartment of the driver and its comfort which is essential for safe driving, an area left to the whims and fancies of body builders, calls for immediate attention for improvement. This paper details many of the parameters required to be looked into such as space, ergonomic design, noise, vibration, heat, safety features, materials used in the cabin, durability, etc. This paper also compares quantitatively the above parameters between the Indian scenario and advanced design/developed countries, as well as mandatory requirements imposed by Occupational Safety and Health Act (OSHA), Bureau of Motor Carrier Safety (BMCS), Federal Highway Administration, US Department of Transportation, etc. It also suggests recommendations for the improvement of the cab as a work place. This paper also presents a case study on a detailed exercise carried out in characterisation and improvement of the vibration levels and methodology of carrying out vibration durability and structural integrity of the cab design for commercial vehicles. |
Automotive Engineering International 2000-09-01 | Improving lightweight vehicle dynamics Bosch engineers used numerical simulation to evaluate vehicle concepts using variable semi-active components, tire specifications, and suspension spring rates. Dr. Reitzle's prescription for Jaguar His vision for the brand is to "use top-level technology and do so in a very emotional way." Dual-voltage power networks Lear Automotive EEDS has developed an innovative electrical and electronic architecture to handle future high-power requirements in vehicles. New door closure concepts Bosch and Temic engineers are developing technologies for passive entry, vehicle immobilization, and remote control. TwinCAN: one module for two nodes The ability to use one module to control two CAN nodes provides benefits including reduced hardware and software requirements, improved functionality, and lower CPU load, according to Infineon researchers. Java for telematics Motorola engineers believe the Java framework will allow the secure deployment of infotainment services to the automobile. Car computing device analysis Unique solutions are required to match computer devices to human needs for a safer, more comfortable driving environment. Electricity builds for Convergence 2000 The automotive and electronics worlds are meshing to an ever-greater extent. Convergence 2000 provides a forum in which engineers and related professionals who populate those worlds come together to explore just how "wired" the vehicle can become. |
Aerospace Engineering 2000-01-01 | Simulation solves C5 cargo door problem Dynamic analysis software allows engineers to solve fatigue-related problems without prototypes. UAV development Although unmanned aerial vehicles (UAVs) have been employed successfully by the U.S. military to date, many development and operational challenges remain for these to become viable alternatives for manned aircraft. Aircraft engine testing: the test tig developer Engineers at Belcan's Advanced Engineering & Technology Division share their insights and experiences on the development of aircraft gas turbine test rigs and stands. This is the first installment of a three-part series on aircraft engine testing. Looking back at factory automation The ability to improve quality while substantially reducing the cost of production and span times is becoming a necessity to complete in today's aerospace industry. Matt Borland, Director of Production Integration on the C-17, Airlift, and Tanker programs, talked about the value that automation presented to the C-17 assembly program. |
Structure Borne Sound Transmission Through a Motor Vehicle | Sound transmission at joints in a motor vehicle is studied using Statistical Energy Analysis. It is shown that transmission at edges of windows can be modelled successfully as transmission past an elastic interlayer. Coupling from the car body to the doors is modelled as transmission across a pin. Corner cross and tee joints between panels are also studied. Measurements were carried out on a motor vehicle using an impulsive noise source and results for acceleration level differences and damping are presented. The measured results are compared with results obtained using a Statistical Energy Analysis model for sound transmission, where only bending wave transmission is considered. Large acceleration level differences are measured and predicted results show good agreement. The results show that Statistical Energy Analysis techniques can be used to study structure borne sound transmission in motor vehicles. |
A Multiplexing Communication IC for Automotive Body-Electronic Control | In the field of automotive body electronic control such as control of door locks, power windows, and wipers, there is a growing need of multiplexing communication to reduce the amount of wire harnesses. To meet this need, we developed a multiplexing communication protocol particularly suited to the body electronic control. Based on the developed protocol, we designed a communication control IC and a simple driver/receiver circuit with a few discrete components. The bus access method of the communication is the CSMA/CD with nondestructive bit arbitration, and its bit rate is 5 kbps. Its transmission media is a single wire. The communication IC has a multiplexing control block and a serial I/O block for an interface with a host CPU. It was fabricated using CMOS technology and has a chip of 2.6mm x 3.0mm in size that contains about 5,000 transistors. The driver/receiver circuit consists of one transistor, one capacitor and several resistors. Therefore, the cost of the circuit is quite low. This paper gives a detailed description of the design specification and features of the communication control IC and the driver/receiver circuit. |
The Design Considerations of an Anechoic Chamber | There are a number of factors that dictate the size, type, and resultant over all cost of a controlled acoustical environment in which measurements can be made accurately and reliably. The type of acoustical environment is generally specified in the appropriate SAE, ISO, ANSI or ASTM standards. The purpose of this paper is to concentrate upon the design considerations of a properly engineered anechoic chamber. Anechoic is defined as ?쐄ree from echoes or reverberations?? An ideal chamber would contain no reflections of sound from its walls, ceiling, or floor and an acoustical free-field condition would exist. Probably the best testing environment is outside with no boundaries to cause reflections. However, temperature, pressure, humidity, and wind can significantly and unpredictably disturb the uniform radiation of sound waves. In an ideal free-field environment, the inverse square law would function perfectly. This means the sound pressure level from a sound source would decrease six decibels for each doubling of distance from the source. For anechoic chambers to function as required to meet the various standards, a number of acoustical, mechanical, electrical, and aerodynamic considerations apply. This paper is intended to briefly address these considerations which include some, or all, of the following: Test object size Anechoic treatment selection Cut-off frequency Test object noise levels Parent room noise levels Vibration isolation Ventilation system requirements Structural requirements Physical access requirements Lighting and electrical requirements Visual requirements Housekeeping requirements RF shielding requirements |
Fast Determination of Vehicle Sound Level per ISO 5130 | Noise from vehicles is a major contributor to community noise. While at high speed often the pavement-tire interaction may be the predominant source, engine noise may also be significant, especially at low speeds. In some European countries most trucks, autos, and motorcycles must be tested at regular intervals per ISO 5130 (1982) ?쏛coustics- measurement of noise emitted by stationary vehicles- Survey method.??The standard requires a measure of the maximum emitted exhaust Fast, A-weighted sound level between a given engine RPM and an idle condition. In the past, the RPM has required a significant time to measure since it requires connecting a transducer somewhere in the engine compartment. This paper discusses an instrument that extracts the engine RPM from the acoustic signal at the exhaust, based on different engine types. This eliminates the need for a direct connection and considerably speeds vehicle tests. |
Practical Applications of SEA CAE Analysis in Vehicle Sound Package Development | Vehicle sound package serves two basic functions: general acoustic insulation and local problem treatment. The former is often done at the up-front phase of the vehicle development process, and the latter at the downstream phase when representative prototype hardware becomes available and specific noise problems are identified. This paper examines the goals and key tasks of practical SEA CAE applications in the two phases of the sound package development process. Topics on CAE model requirement, typical analysis applications, and ways to improve the effectiveness of SEA applications to compliment hardware testing are discussed. |
Wind Noise and Aerodynamic Drag Optimization of Outside Rear View Mirrors | Automotive outside rear view mirror shape has become an important consideration in achieving wind noise and aerodynamic performance objectives. This paper describes a two step process used to develop a mirror shape which meets both wind noise and aerodynamic objectives. First, basic understanding of door mounted verses sail mounted mirrors and shape parameters was obtained by evaluating selected shapes and studying their physical measurements relative to their measured responses. Relationships between the wind noise and drag responses revealed performance range limitations for sail mounted mirrors. Second, a central composite experimental design was utilized to more closely investigate door mounted mirror shape parameters to determine optimal mirror performance potential. The resulting empirical models developed were used to determine the best overall solution. |
Development of Door Beam ERW Tubing Made of 1470N/mm2 Cold Rolled High Strength Steel Sheet | To develop ultra high strength ERW tubing for the door beams of passenger cars using cold rolled steel sheet, an FEM analysis was performed using a tubing deformation model which simulated door beam testing. In the elastic and plastic FEM analysis, the effects of the yield strength and tensile strength of the steel sheet on tubing properties were investigated. The results showed that the tubing peak load in three-point bending increases with an increase in tensile strength. An increase in yield strength enhances the endurance load in the early stages of deflection while it slightly accelerates buckling. The analysis resulted in the production of TS 1470N/mm2 grade cold rolled sheet to be manufactured into ERW tubing. A 0.22%C-0.4%Si-2.4%Mn-0.03%Nb cold rolled steel with a thickness of 2mm was processed in a continuous annealing line which employed water quenching. An ultra high tensile strength along with a relatively high yield ratio was obtained by the introduction of large amounts of tempered martensite into the microstructure. ERW tubing made from cold rolled sheet with a tensile strength of 1470N/mm2 and a yield ratio of 0.82 showed, in actual door beam testing, as high a peak load and absorbed energy as conventional induction heated and quenched ERW tubing made from hot rolled steel. These results show the potential for a more economical manufacturing process. |
Clean Digital Data Acquisition With Anti-Aliasing Filters | When acquiring low-data-rate signals such as temperature, engineers sometimes forget that low-data-rate sampling does not guarantee an uncontaminated recording. Regardless of the sample rate employed in digital data acquisition, signals entering the sampler above half the sampling frequency will be reflected and added into the band below to distort and corrupt the signal of interest. |
A New Optimization Approach in the Field of Structural-Acoustics | It is shown in how far modal correction techniques can contribute to reduce the CPU effort in the scope of numerical structural-acoustic investigations. Due to this technique a quasi-online interactive acoustic optimization of a basic system configuration can be achieved. In this context special focus is pointed on structural optimization aspects. Finally, the limits of validity as to the accuracy of the results obtained by the modal correction approach in the case of larger modifications are determined. |
Improving Vehicle Windshield Defrosting and Demisting | This paper examines the prevailing fluid flow and heat transfer on the windshield of a full?뱒cale vehicle and examines ways of promoting efficient de?밿cing and demisting. It establishes that present methods of defrosting and demisting windshields are inefficient; since the first area cleared is below the driver's eye level and even this result only occurs some considerable time after the blower has been switched on. The complexity of the windshield topography and the defroster nozzle geometry yield inadequate flow mixing, poor momentum interchange and consequently dead flow zones in critical visibility areas. This study explores ways of improving the defrosting and demisting process through passive means and using the existing air handling system of the vehicle. The results presented are from numerical simulations validated by experiment. |
Acoustical Selection of Class 8 Truck Floormats | Class 8 truck manufacturers use a wide variety of materials for cab floor construction. These include traditional steel and aluminum plate as well as aluminum honey-comb and balsa wood core composites. Each of these materials has unique transmission loss properties. The acoustical performance of the floor system, (cab floor, decoupler, and barrier) depends not only on the acoustical performance of the decoupler and barrier, but also on the cab floor material. This paper outlines an experimental technique for selecting an acoustical floormat system utilizing vehicle and laboratory tests that takes these factors into account. |
Squeak and Rattle - State of the Art and Beyond | Modern trends in noise control engineering have subjected the automobile to the ?쐂rained swamp??syndrome. Squeaks and rattles (S&R) have surfaced as major concerns. Customers increasingly perceive S&R as direct indicators of vehicle build quality and durability. The high profile nature of S&R has led manufacturers to formulate numerous specifications for assemblies and components. Even so, a large majority of buzz, squeak and rattle (BSR) issues are identified very late in the production cycle, some often after the vehicle is launched. Traditionally, the ?쐄ind-and-fix??approach is widely adopted, leading to extensive BSR warranty bills. The ?쐂esign-right-the-first-time??approach must replace the ?쐄ind-and-fix??approach. Due to the vast breadth and depth of S&R issues, a comprehensive summary of the present state of the art is essential. This paper includes a literature survey of the current state of the art of S&R, and discusses the methods available to further advance it. Dedicated and focused attempts to advance the state of the art require the formulation of an integrated design strategy that attacks S&R during the earliest stages of design and development, leading to substantial savings in fix and warranty bills. |
Enhanced Series of Mid-Size Agricultural Tractors | The J I Case Company recently introduced a new series of Maxxum tractors (Figure 1). The product line now offers 60, 67, 75, and 84 PTO kW versions. The all new 84 kW version features a new fuel delivery system providing both greater power and reduced exhaust emissions. The powertrain also features increased capacity components required for the reliability of the increased power, 84 kW model. The new series incorporates numerous customer requested improvements of the 5100 Series, including increased comfort, convenience, and visibility features such as swivel seat, in-cab remote coupler flow controls, fender mounted hitch controls and all glass doors. |
Upper Extremity Injuries Related to Air Bag Deployments | From our crash investigations of air bag equipped passenger cars, a subset of upper extremity injuries are presented that are related to air bag deployments. Minor hand, wrist or forearm injuries-contusions, abrasions, and sprains are not uncommonly reported. Infrequently, hand fractures have been sustained and, in isolated cases, fractures of the forearm bones or of the thumb and/or adjacent hand. The close proximity of the forearm or hand to the air bag module door is related to most of the fractures identified. Steering wheel air bag deployments can fling the hand-forearm into the instrument panel, rearview mirror or windshield as indicated by contact scuffs or tissue debris or the star burst (spider web) pattern of windshield breakage in front of the steering wheel. |
A Methodology for Evaluating Barriers and Aids to Vehicle Ingress/Egress | A methodology for evaluating aids and barriers to vehicle Ingress/Egress (I/E) was developed to assess subject performance with prototype features designed to improve I/E. The measures used included Perceived User Difficulty, Total Time to perform a task, and Observed Body Movements identified during video analysis of the I/E tasks. The observed movements included foot/door interference, movement discontinuity, trunk rocking, and upper extremity usage. Pilot testing of this methodology showed that subjective and objective user preference and performance data could be measured and that this information provided a more complete understanding of the problems associated with specific prototype solutions. |
Current and Future Trends of Cabin Trining Simulation | Currently, the airline industry is demanding increased performance from its training staff and training systems. And today, optimal training performance depends on new technology. This challenge has led to the creation of systems that offer a broader range of cabin training solutions. One new system is the IntelliDoor?? This new system is an intelligent door training program that integrates the latest touchscreen computer technology with multi-media interaction and proven instructional methods. The result is a product that delivers consistent, precise, self-paced training without the need for constant instructor supervision. |
High Precision in Car Body Manufacturing | Flexible car body production, including prototyping, is one answer to the market targets where customers ask for an increasing number of models / variants and shorter lead time. The in-house interests of car builders are, besides investment and manpower flexibility, also improved product quality. Quality in body in white is mainly related to geometry (= high precision), to make sure that the final assembly shops will have the right conditions to keep customers satisfied (flush in doors, hood, fenders etc.). The consequences are that both the product and the process equipment have to be in a stable condition to guarantee low spread in the complete car-body. CAD technology is one of the keys to reach this goal, where: Off-line tooling Off-line programming Flow simulation Measurement strategy, off-line / in-line are the main powerful tools to reduce lead time as well as costs. In the realisation phase of the new flexible body shop, in VTK / Gothenburg Sweden, new methods were used for the interaction with all process-suppliers. The co-operation at early stages was highlighted under the aspect of simultaneous engineering. The bottleneck was to find an overall measurement strategy that could be used in all phases of the project, including maintenance during later production. Geometry-wise the targets, for the complete car body, were focused on completely new demands in body-in-white history, with dimensions defined as: ??0.2 mm spread in stamped parts, ??0.5 mm spread in pre assembled parts, ??0.7 mm spread in complete car bodies, for functional values. To reach these values, a metrological concept was developed with a Norwegian company, before the start of the project, and later implemented in our work routines as a standard tool. Process equipment from the main suppliers for the new flexible body shop was controlled geometrically by Volvo-teams with transportable Metronor systems during the three phases: Equipment assembly at suppliers site, Installation on site, Maintenance in production, using the same method of measurement. The result out of this project was that car no. 1 already showed customer quality, even if control-fixtures were not used in the flexible body shop. |
Sound Quality in Cars: New Ideas, New Tools | In recent years, car manufacturers have been shifting their efforts towards improving quality of interior noise, rather than simply reducing noise levels. One of the most important issues, which is today widely accepted, is that noise contains information. Slamming noise should warn us that doors are safely closed, control panel pushbutton ?쐁licks??inform us about the correct turning on of devices, etc.. One of the acoustic researchers' task is therefore to modify the original noise to emphasize quality of information and to reduce annoying components. For these reasons, it is very important to affect noise timbre, by investigating the relationships between mechanical and acoustical parameters. In this paper we describe a workstation (which we have called N.O.T.E.: Noise Optimizator for Thermal Engine) for intake and exhaust system noise synthesis, that integrates an acoustical simulation code with a synthesizer. By means of this flexible system, it is possible to lay out the engine acoustical model, starting from physical laws and using a few general purpose predefined blocks (such as noise sources, resonators, filters, etc.) in a CAD environment. The most important feature of the sound synthesis workstation is the possibility of changing all parameters in real time, making it feasible to ?쐏lay??every kind of engine noise, before building any prototype. |
Glass Drop Design for Automobile Windows - Design of Glass Contour, Shape, Drop Motion, and Motion Guidance Systems | This paper presents a new computerized approach for designing the automobile window glass contour, the glass drop motion, and the regulator systems. The three-dimensional geometrical relationship of the glass contour, the drop path, and its guidance system have been studied. Methods for barrel and helical drops are presented for optimizing the glass profile and drop path trajectories. Criteria for perfecting the glass contour are developed for shaping the profile of the vehicle clay model. Methods for correcting the glass contour and shape are presented. Examples are provided to illustrate how to improve the design. This approach integrates the development works of glass contour, drop motion and regulator systems. Through this design approach the window glass can fit and move perfectly in the door assembly. |
J1850 Compliant Chip Set | The J1850 Automotive Multiplexing System is opening up new opportunities for automotive designers. Multiplexing not only reduces wiring, weight and cost; but is also adding features by sharing information among modules. For example a door module could communicate that the car is being unlocked and who is unlocking it. The body controller can use this information and tell smart seats and mirrors to adjust themselves to that driver's preferences; tell the radio to turn to a particular station and start the engine. The number of modules that are being multiplexed are increasing in both number and function. Everything from sophisticated engine controllers to simple actuator/sensor nodes are being multiplexed. The challenge with Multiplexing a large number of modules is how to make an integrated circuit that fits all their diverse needs. A complex module, like an engine controller, requires the integrated circuit to be sophisticated enough to handle all the message buffering and filtering functions. Whereas a very cost sensitive, low end module does not require the same performance. How does an IC meet the conflicting needs of an increasing number of modules? Harris Semiconductor found an answer by taking a building block approach. Harris implemented the J1850 analog and digital functions into separate integrated circuits. Doing this not only developed a flexible solution but one optimized to a degree not possible using a single integrated circuit. This article will explain how the three Harris J1850 integrated circuits (HIP7010, HIP7020 and the HIP7030) make up a flexible and cost effective solution for the J1850 Variable Pulse Width Modulation (VPW) Standard. |
Designing Mobile Air?밹onditioning Systems to Provide Occupant Comfort | The designer of mobile air?밹onditioning systems must consider the total vehicle in order to provide occupant comfort. An effective refrigerant circuit is only one portion of the vehicle ?쏞omfort System??and without the system's ability to deliver adequate cooling it will not meet the consumer's expectations. A significant considered is the design of the vehicle's body, including the panel outlets and the extent of window glazing surfaces. The location of the panel outlets to provide the occupant's adequate and controllable system airflow for changing weather conditions is a major factor in achieving comfort. Window glazing locations and areas have a major effect on increasing the air?밹onditioning thermal load by allowing direct solar radiation into the vehicle. Unfortunately, the styling of the vehicle dictates these areas and these constraints very often result in the customer having an air?밹onditioning system that provides an unsatisfactory level of performance. This paper provides an overview of some areas that are not always given adequate consideration during development of a new vehicle and its air?밹onditioning system. |
Geometries of Simple Hinges Hidden by Flush Contoured Surface Doors | Doors are very important parts of transportation products as exemplified by the large number of them. In addition to doors for occupants to enter and exit there are doors for access to engine, cargo, luggage, air flow, fuel fill, etc. For transportation products, doors are usually designed to be flush with surrounding surfaces -- and most of them have hidden hinges . There are only a few mechanical alternatives to provide for the opening of doors and the use of simple pivoting hinges is predominant. There are two kinds of simple pivot hidden hinges -- in swinging and outswinging. These are named according to the initial motion of the edge of door with respect to its adjacent surface. Inswinging hinges are most prevalent for occupant entry/exit doors since they are required for most rear doors and they provide more pleasing cut line shapes for current surfaces, usually at lower cost. The door cut lines for hidden hinges which studio designers initially style on proposed products frequently cannot be achieved due to the inherent limitations. While achievable cut lines can be developed using trial -and- error methods, quicker and more reliable results together with a true understanding of the problems requires an analysis which identifies causes and simplifies their visualization. Such an analysis has led to a system for establishing the limits of surfaces and cut lines which has been named the ?쏺olume-in- Space??method. It was developed originally for automotive occupant doors but is also applicable to other transportation items such as doors for luggage, engine, air flow, fuel, etc. as well as other pivoted parts such as convertible tops and aerodynamic suspension arms -- and even non- transportation hinged applications such as cabinets and machinery housings. As the top end view of a hinge center line for automotive occupant doors is observed, there are four basic limits to the volume in which the edge of the door must be contained. These limits are (1) the Swing-By Limit, determined by the requirement of the door swinging clear as it passes by the adjacent panel (or door) at initial movement, (2) the Molding Clearance Limit, determined by the requirement that any randomly located molding on the vehicle surface must not be contacted when the door is fully opened, (3) the Swung Limit, determined by the requirement that the door and the body parts must not contact each other when the door is swung fully opened, and (4)) the Inner Limit, determined by the most inward exterior surface possible with respect to the hinge on the door or other hardware in the door. By examining the parameters which affect each limit, projections can be made regarding ways of increasing the size of the limiting ?쏺olume- in-Space?? Additional discussion is included on advantages for occupant entry/exit which have been gained in some products by orientating the hinge centerline at angles up to 4째 from vertical. There are also opportunities for improving the door openings for both body structure and occupant entry/exit. |
Advanced Materials and the Pivoting Door Reverser | HUREL-DUBOIS patented a new concept of thrust reverser in 1981 known as ?쐔he door forward reverser?? It gives numerous advantages over the conventional cascade reverser, and in particular is inherently lighter. The extensive use of advanced materials has allowed a highly competitive weight to be achieved. This paper describes the work currently under way for the pivoting door reverser for the ROLLS-ROYCE Trent engine and covers: Thrust Reverser door structure predominantly in composite. Acoustic treatment with composite sandwich. IFS design with carbon bismaleimide material This reverser will be used on MD11 and Airbus A330 aircraft. |
Innovations in Design and Functionality of Acoustical Insualtion | In response to the demands of today's automotive market, advancements have been made where acoustical insulation does much more than just reduce noise. Insulators are now being manufactured to precise tolerances allowing for improved value added features, while also reducing part count and simplifying assembly. In addition, methods have been developed to reduce part weight and provide a product that is fully recyclable while maintaining superior acoustical performance. |
Investigation into the Noise Associated with Airbag Deployment: Part II - Injury Risk Study Using a Mathematical Model of the Human Ear | Airbag deployments are associated with loud noise of short duration, called impulse noise. Research performed in the late 1960's and early 1970's established several criteria for assessment of the risk of impulse noise-induced hearing loss for military weapons and general exposures. These criteria were modified for airbag noise in the early 1970's, but field accident statistics and experimental results with human volunteers exposed to airbags do not seem to agree with the criteria. More recent research on impulse noise from weapons firing, in particular that of Price & Kalb of the US Army Research Laboratory, has led to development of a mathematical model of the ear. This model incorporates transfer functions which alter the incident sound pressure through various parts of the ear. It also calculates a function, called the ?쐆azard?? that is a measure of mechanical fatigue of the hair cells in the inner ear. The repeatability of the model was examined in the present study by comparing its predictive behavior for airbag noise impulses generated by nominally identical airbag systems. Calculations of potential ?쐆azard??made by the model were also examined for reasonableness based on mechanical and biomechanical considerations. A large number of airbag noise pulses were examined using the model. The results provide some counter-intuitive insights into the mechanism of noise-induced hearing loss from deployment of airbag systems. They also indicate that, based upon testing of feline subjects (which are believed to be a good indicator of the risk to the more susceptible segment of the human population), there could be a risk of temporary and possibly permanent threshold shifts in approximately sixty seven percent of the 1990-1995 model year vehicles from 19 manufacturers which were tested and assessed using the human ear model. A statistical estimate of the risk for the human population has yet to be quantified, but work is in progress to do so. Work is also underway to develop a pre-production airbag component test for deployment noise that component suppliers can incorporate into the design and development process. Once injury risk curves and test protocols are established, it is recommended that the ARL Human Ear Model be utilized by the automotive community as the assessment method of choice. |
An Innovative Light Weight Instrument Panel Reinforcement Structure | A light weight, cost effective IP reinforcement structure with a high degree of resistance to steering wheel vibration and with a safe and efficient crash energy management has been developed by Alcoa Automotive Structures (AAS). It also demonstrates other desirable attributes like modularity for world-car platform applications and improved dimensional consistency. The design was analyzed using finite element methods (FEM) for vibration and crash performance and prototype assemblies have been tested. Results demonstrate conformance to vibration and crash response expectations. The concept demonstrates viability and benefits of Alcoa's multiple material and product form solution for IP structures. This paper describes the design and shows some of the analysis and test results |
Anti-Trap Function for Electrical Power Windows | Today electrically driven windows are a standard feature in many automobiles. Further technical enhancements like express up/down or remote controlled central closing are important features for increased comfort and ease of operation. Some of these new functions cannot be implemented without inherent safety precautions to avoid the risk of being trapped and severely injured by automatically moving window panes. A sophisticated technical approach is described which solves this problem using state of the art electronics and modern software design combined to yield high cost efficiency. This patented concept is based on motor current detection. Theoretical explanations and practical results illustrate that it is superior to other approaches. Examples are shown of high volume applications currently in production. |
Practical Noise and Vibration Optimization of HVAC Systems | Next to air temperature, humidity, and air quality, it is sound emission that exerts a significant impact on the driver's and passenger's comfort. Major progress in vehicle acoustics has motivated vehicle manufacturers and systems suppliers to evaluate HVAC systems no longer by their air conditioning performance alone. Sound emissions and sound quality have become additional important criteria for the development of new HVAC systems. In the initial conception phase, where systems and packaging considerations are made, acoustic optimization must begin with preliminary system studies and feasibility studies. In this phase acoustics should be based on fairly general systems specifications which describe the desired degree of acoustic comfort. In the subsequent design phase follows the specification of the acoustic goals and the optimization of the HVAC unit. Detailed analysis and optimization of air flow and blower are the common targets for improvement at this time. Finally, component optimization starts with including the detailed design process and the mounting of possible noisy components. The paper further outlines four pillars, on which good acoustics of an HVAC system is based, focusing on the subsystem ?쁝ir flow?? These are reduction of pressure drop, flow optimization, sound proofing and sound deadening, and at least the insulation of structure borne sound. |
Psychoacoustic Considerations in Vehicle Ergonomic Design | In order to experience harmony among the various perceptual cues experienced by an automobile customer, the acoustic environment must be considered. Acoustic events generated by automotive systems can have a dramatic effect on a customer's impression of vehicle quality and reliability. Additionally, certain vehicle segments are partially defined by the vehicle's sound characteristic. For example, luxury segments are defined by quiet and smooth powertrain sound, whereas some sports car segments are defined by loud and rough powertrain sound. This paper is a discussion of the impact automotive acoustic events can have on the customer. Addressed will be the methods typically used in both data collection and subsequent jury evaluations. Two case studies will be discussed. Finally, there will be a brief discussion on the future role of psychoacoustics in the vehicle environment. Exploring the relationships between acoustic, visual and haptic stimuli is an area which has been largely unexplored. Additionally, auditory warnings and displays may become increasingly important in advanced safety and navigational systems and can be positively influenced by psychoacoustic principles and methods. |
International Space Station Temperature and Humidity Control Subassembly Hardware, Control and Performance Description | The temperature and humidity of the air within the habitable areas of the International Space Station are controlled by a set of hardware and software collectively referred to as the Temperature and Humidity Control (THC) subassembly. This subassembly 1) controls the temperature of the cabin air based on a crew selected temperature, 2) maintains humidity within defined limits, and 3) generates a ventilation air flow which circulates through the cabin. This paper provides descriptions of the components of the THC subassembly, their performance ranges, and the control approach of the hardware. In addition, the solutions of the design challenges of maintaining a maximum case radiated noise level of NC 45, controlling the cabin air temperature to within 짹2째F of a setpoint temperature, and providing a means of controlling microbial growth on the heat exchanger surfaces are described. |