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Development of Sound Localization Control System for Car Stereo | In a two-loudspeaker stereophonic reproduction system of a passenger car, the geometrical configuration of the right and left loudspeakers has the disadvantage of being asymmetrical to the listener. For this system, we have made both theoretical and experimental verifications of the effects of strongly reflected sounds on the sound pressure level difference and phase difference between two ears which determine the location of sound image in a small compartment of a passenger car. On the basis of these verifications, we have developed a new sound localization control system. With this system, acoustical effects such as sound expansion and ambience have been greatly improved in a passenger car. In this system, input signals to the loudspeakers are controlled so that the sound image produced by the loudspeaker nearer to the listeners may acoustically move so as to position itself symmetrically with the other loudspeaker with regard to the listeners. The corner-mounted loudspeaker and the sound localization control circuit constitute the distinctive features of this system. The corner-mounted loudspeaker suppresses strongly reflected sounds, which are characteristic of the sound fields in a passenger car, and improves the definiteness of acoustical sound localization. The corner-mounted loudspeakers are installed toward the corners of the intersections of the instrument-panel near the right and left doors so that the directivity axis of loudspeakers makes an equal angle of 45 degrees with the two vertical planes passing through the instrument-panel and each door. The sound localization control circuit consists of an inverter, a pre-amplifier and a delay circuit unit. This control circuit is connected to the power amplifier output stage of a conventional audio components. With this circuitry, acoustical effects such as sound expansion and ambience are greatly improved. |
Aerodynamic Characteristics of the Fiat UNO Car | The purpose of this article is to describe the work conduced in aerodynamic field throughout the 4-year development and engineering time span required by the project of the UNO car. A description is given of all the parametric studies carried out. Through these studies two types of cars at present in production were defined and the characteristics of a possible future sports version laid down. A movable device, to be fitted in the back window, was also set up and patented. When actuated it reduces soiling of back window. A description is also provided of the measurements made in the car flow field and some considerations are outlined about the method applied. This method is still in development phase but it already permits some considerations and in-depth investigations to be made on the vehicle wake. |
The National Highway Traffic Safety Administration's Evaluations of Federal Motor Vehicle Safety Standards | A history of the evaluation of existing motor vehicle safety devices by the National Highway Traffic Safety Administration and other researchers. The discussion emphasizes observations of researchers toward the safety standards and the extent to which these have influenced or were influenced by evaluations. Issues concerning energy absorbing steering columns, head restraints, side door beams and windshield glazing and bonding are covered in detail. This paper presents the views of the author and not necessarily those of the National Highway Traffic Safety Administration (NHTSA). |
System Electromagnetic Compatibility Through Component Testing - An Overview | By nature, automotive electronic systems are susceptible to Electromagnetic Interference (EMI). Devices capable of suppressing EMI have become an integral part of the automotive electronic system design. Methods of testing these devices individually and as part of the total electronic system have been developed and used as a design tool by the engineer. These methods range from individual component tests to total electronic system analysis and cover such areas as radiated noise susceptibility and the effects of electrical transients on the electronic system. The ability to test components in the laboratory allows the engineer to assemble reliable subsystems from which a total electronic system may be designed. Components and subsystems may be tested using a TEM cell, anechoic chamber and/or direct injection of noise signals. Computer control of the test provides repeatable results and better turn-around time than can be obtained by manual testing. This paper will present different methods of performing Electromagnetic Compatibility testing on components and electrical subsystems. Procedures for characterizing susceptibility to EMI will be reviewed and its applicability to the design process will be discussed. Case histories will be included to illustrate the advantages of component and subsystem testing to total vehicle analysis. |
Application of Acoustic Intensity Measurement to High Frequency Interior Noise | This paper describes the application of an acoustic intensity measurement method to high-frequency interior noise. Technical problems in applying an averaging technique via surface scanning to high-frequency interior noise were conquered, and detailed quantitative contribution analysis of interior surfaces was made possible. Based on the analysis of a small passenger car, the effectiveness of additional noise control treatment can be roughly estimated, and an acoustic confort of the car was improved by a minimum additional treatment required. |
Aeroacoustic Flight Test of Four Single Engine Propellers | A flight test program has been conat the Aeronautical and Astronautical Research Laboratory (AARL) of The Ohio State University to measure performance and acoustic characteristics of four propellers designed for use on single-engine general-aviation airplanes. Three of the propellers were designed to reduce acoustic noise, while the fourth was a standard production propeller used for comparison. The tests show that notacible reduction in near-field noise was achieved at a constant propeller rpm, and that comparable aircraft performance may still be maintained. |
Application Of The Finite Element Method To The Design Of The Front Door Of A Light Commercial Vehicle | The paper describes the development and application of a relatively fine mesh model, analysed using MSC NASTRAN, to predict absolute values of deflections which correlated closely to the mean measured deflections of the actual door. The model has proved valuable in identifying and correcting at the pre-production stage the problem of the front door fit conditions. The paper then discusses the application of the model for structural analysis using strain energy techniques. The resulting design gives 21% reduction in deflection and stress at critical points with only 3% increase in mass. This contributed to significant savings in proto-type testing and in addition, provided more efficient use of the material in the structure. |
Development of Multiplex Wiring System with Optical Data Link for Automobiles | This paper contains an explanation of a Multiplex Wiring System with Optical Data-Link for cars, which has been installed in the Toyota “Century” since 1982. In this system, a total of 64 signals related to door wiring are transmitted in a multiplex fashion, and the number of wires from the front right-hand door to the interior could be reduced from 46 wires, which were used with conventional wiring techniques, to 10 wires including 2 plastic optical fibers. This system also has various control functions which includes a door-lock control function. In order to give high reliability to this system, we have developed a new optical data-link as well as a new custom micro-computer. And in the automobile industry, such a large scale multiplex wiring system having high reliability is very innovative in our opinion and will surely have a large impact in the future. |
Maxi-Mini Car | This paper investigates an alternate design for a small car with maximum interior space. The most advantageous design was found to be a three seater vehicle with a possible fourth seat. The driver is positioned in the center of the vehicle. All seats are movable front and aft and sideways and the trunk is variable giving maximum space utilization and versatility. The car has unique folding doors which swing up far into the roof for easy accessability to all seats. Space for 3 or 4 people is provided in a vehicle of less overall dimensions than current designs. Through use of plastic materials weight is also lower guaranteeing excellent fuel economy. |
The Ejection Reduction Possibilities of Glass-Plastic Glazing | Ejection is a major problem in motor vehicle safety, with some 43,000 people per year being ejected from passenger cars, with some 6000 of these killed. About half of these people killed are ejected through glazing areas. The November, 1983, amendment of Federal Motor Vehicle Safety Standard 205 now allows the use of glass-plastic glazing anywhere in a motor vehicle. Our study has explored the “safety net” implications of glass-plastic glazing, produced by Saint-Gobain Vitrage, 3M, and DuPont for the anti-laceration implications but tested in our study for reducing ejections by controlled deformation after the glass layer or layers break. The inner plastic layers holds the broken pieces of a tempered side glazing together enough to reduce adult head partial ejection in side impacts, with the plastic layer trimmed to the glazing edges. By extending the plastic layer and securing it to the window channels, a 44 pound child moving at 20 mph toward the window may be stopped without ejection, with severe but possibly tolerable neck loads. Plastic layers which allow a greater deformation without failure appear desirable, to give glass-plastic glazing both a reduced laceration and a designed reduced ejection capability. This paper presents the views of the authors and not necessarily those of the National Highway Traffic Safety Administration (NHTSA). |
The Performance of Automobile Glazing in Urban Accidents | Laminated glass windshields have not yet been demonstrated to be safer than a less expensive, single sheet of tempered glass. Data from injury-producing urban traffic accidents in Australia, involving tempered glass windshields, reveal that while the windshield is a major cause of injuries, they were generally slight and rarely disfiguring. By modifying the method of mounting the tempered windshield and by controlling the particle count near the periphery of the windshield, the risk of laceration may be greatly reduced. |
Correlation Between Windshield Head Injuries and Laboratory Tests Part I: Feasibility of Relating Headform Impacts to Clinical Head Injuries | By duplication of glass fracture patterns, the feasibility of relating 22 lb headform impacts to head injuries sustained by occupants contacting the windshield in crashed vehicles has been established. For each suitable windshield sample selected from available 1966 to 1969 crashed automobiles, a vehicle analysis was performed. The unbroken sections of 33 selected windshields were subjected to dynamic loads using the 22 lb portable headform. This portable device mounted in a van is described. At impact, the deceleration and velocity were measured and lacerations rated on the basis of damage to simulated tissue and moist chamois. Achievement of duplication between headform and occupant head impacts permits a numerical assessment of windshield lacerative injuries and presents a tentative method for future programs involving correlation between laboratory and service performance. |
Side Impact Structures | New side safety structural changes have been developed for some 1969 model General Motors cars. The research covered two years, during which time crash situations were simulated and analyzed, field data were studied, and various approaches to side protection were investigated. A low-weight, high-strength steel beam was developed and positioned horizontally in the door. In addition, the supporting body structures were reinforced. The resultant structure reduced penetration into the passenger compartment during side collision tests by causing a deflecting action between the two cars, and by preventing ride-over of the striking vehicle into the struck car. Fisher Body has recently developed the basis for a static laboratory technique of testing that measures the strength of side impact structure in such a way as to allow tryouts of designs early in the program. Because of the number of GM cars designed each year, this will curtail the extensive time and cost factors previously involved in dynamic testing. |
Elastic Vibration Analysis of Passenger Car Bodies (Bending and Torsion) | This paper presents the outline of a theoretical analysis of bending and torsional vibration of passenger car bodies. Body structure is simulated by a framework with tension rigs and additional panel stiffnesses. The framework is a three-dimensional model for the bending and torsional vibration, or two-dimensional for the bending vibration, and is analyzed by the lumped mass system. All input data are calculated from drawings, and therefore characteristics of body structure are forecast and controlled in the design process. The analysis is also applicable to coupled vibration and forced vibration problems. |
Perforation Corrosion at Lapped and Cold Formed Portions in Cold Rolled and Galvanized Sheet Steels | In order to prevent corrosive parts such as hood, trunklid, door and side sill in an automotive body from corrosion, a new perforation corrosion test to simulate the corrosion at lapped and cold formed portions was conducted on cold rolled, galvanized, and zinc rich primer coated steels. Anti-perforation of galvanized steels with zinc of 95 or 128 g/m2 and galvannealed steel with zinc-iron of 59 g/m2 is remarkably improved compared to cold rolled DDQ mild steel so that they decrease the reduction in thickness to about 1/2 or 1/3. Especially galvannealed steel showed the highest protectivity. On the other hand, effect of steel itself on perforation is also observed among three uncoated steels. The EDDQ high strength steel has excellent resistance. The reason can be attributed to low manganese content and lack of surface segregation of manganese due to short time continuous annealing. |
Realization of Pedestrian Protection Measures on Cars | For the first time a working group of german universities developed an efficient, environmentally compatible and safe passenger car. The design of the UNI-CAR was specifically adjusted to the safety of persons outside the vehicle. Thus, for protecting pedestrians and drivers of two-wheeled vehicles, several of the bodywork components were primarily developed on the basis of polyurethane integral skin foam to cushion the impact of a person upon the car from outside. For instance, the car was given a reversibly deformable front end and a cushioned bonnet as well as cushioned window frames and roof edges, without impairing the design or aerodynamics of the vehicle. The report explanes the aspects of materials selection and vehicle design, the problems and experiences associated with the manufacture and application of these plastics components as well as test results. |
The All-Aluminum Auto Body - A Study Based on the Porsche 928 | An all-aluminum body in a unitized construction of a sportscar has been developed as a prototype. Design features, forming, welding, and surface treatment have been studied as well as the results of the test trials. A weight-saving of 47 % compared to an all-steel body was achieved with good characteristics of static and dynamic stiffness, operational reliability, passive safety properties, corrosion resistance, noise level, and repairability. |
Electric Vehicle Operational and Impact Safety Testing-Presentation of Test Results and Safety-Related Vehicle Problem Identification | The National Highway Traffic Safety Administration has completed safety-related testing of 13 electric vehicle models which are presently on the market. This report summarizes the results of the hydraulic brake, windshield defroster, and 30 mph frontal barrier impact tests which were conducted. Performance trends are discussed and safety-related problems and defects are identified. |
RIM Urethane/Vinyl Composites as interior Trim Parts | Approximately four years ago, new production process for automobile door liners was introduced in Europe. The process consisted of stretching a sheet of unsupported, expanded PVC over the mold cavity. The mold was closed and clamped and a polyurethane structural foam mixture was injected by the RIM method through the top half of the mold. The pressure and temperature of the expanding mixture forced the vinyl to conform to the contours of the cavity thus producing a finished door liner (polyurethane foam/vinyl composite). This process showed promise but had several drawbacks. Over the past two years, cycle times have been reduced to 2 minutes, intricate surface detail has been achieved and other formable surfaces have been substituted for the vinyls. These improvements have made it a candidate product for the U.S. auto industry. |
Quantitative Measurement and Predictive Techniques for Radio Frequency Interference | A technique for measuring and predicting radio frequency interference has been developed which can quantify an individual component’s performance, The assessment of a quantitative performance objective for each component provides a means to acheive a desired level of noise rejection for the system independant of environmental variances. |
Materials for Panel Damping in Motor Vehicles | This paper describes the application possibilities of materials for panel damping in modern motor vehicle construction. The basic parameters which govern damping are given; it is shown how they relate to motor vehicles. Two laboratory test methods are discussed for determining the damping performance of materials typically used in motor vehicles. Examples of the effectiveness of such treatment in the motor vehicle under normal operating conditions is presented and discussed. The influence of damping materials when combined with other typical noise control materials is shown in regards to performance and weight optimization. |
Torsional Vibration Measurement and Analysis: A New Technique | Torsional vibration measurements, while varying in complexity, are probably the least familiar type of vibration measurement. The high output demands imposed on today's engines require a complete understanding of torsional vibration. This understanding is necessary to insure proper function and durability of these engines and their components. The need for an accurate, reliable and durable measurement system that could be used for the evaluation of any engine application is essential. The measurement system has two basic components, an engine mounted transducer and signal conditioning/data reduction equipment. The transducer must be selected before other system components can be identified or developed. A prototype transducer has been evaluated and proven to meet the above criteria. Its performance has been verified with the use of redundant test methods. This instrumentation included proximity probes, linear accelerometers, an angular velocity transducer and optical methods. The linearity response of the transducer was excellent on all the subjected test set-ups. The device responded equally well to either rotating or non-rotating inputs. Eccentric locations of the transducer were shown to have minimal effects on the output response. Temperature compensation must be built into the production transducer and accurate readings can be expected from 25°F (−3.8°C) to 250°F (121°C). The future of this device looks very promising and the range of applications extend from torsional testing and machinery diagnosis to continuous systems monitoring. |
Evaluation of the Acoustic Intensity Approach to identify Transmission Paths in Aircraft Structures | The new two-microphone acoustic intensity technique has been applied to the determination of the transmission paths of sound into an airplane cabin interior. It appears that, provided sufficient care is taken in the measurements, accurate quantitative information can be obtained with this technique on the dominant paths of acoustic energy transmission. This information can be used to make design changes to the fuselage wall to reduce interior cabin noise. |
Brief Status Summary for Automatic Speech Recognition at the start of the 80’s | Automatic speech recognition has demonstrated high capability, first in the laboratory and now in field operations. This summary presents the characteristics of today’s research and commercial systems, and discusses issues and trade-offs affecting their performance. Independently conducted tests of Dialog System’s new speaker dependent, real time continuous speech recognition system demonstrated 99.5% word recognition accuracy in a task with a vocabulary of 10 digits plus 10 control words. The words were spoken by 5 speakers (3 male, 2 female) in a variety of regional American dialects against a background of heavy machine clatter and other noise. |
The Effect of Noise Legislation on Vehicle Diesel Engine Design | Proposals in both Europe and the United States for future reductions in vehicle noise limits can be expected to have radical effects on the design and installation of truck diesel engines. A review of published accounts of quietened trucks shows that mostly engine enclosure has been used. There are short term incentives for manufacturers to use this approach, but it is not the most cost effective solution in the long term and has numerous problems including that of maintaining noise levels throughout the service life of the vehicle. Greater incentive is needed for radical redesign of the diesel engine to make it inherently quiet and to minimise both the on-cost and the energy penalty of noise reduction. This paper develops the theoretical background to this problem. Starting from the basic characteristics of vehicle noise, a philosophy of noise control is developed and practical means of achieving the desired noise control are discussed. |
700 H.P. TRUCK TRANSPORT | SIGNIFICANT REDUCTION IN THE TRANSPORTATION COST PER TON MILE OF BULK PRODUCTS IS ATTAINABLE BY THE PROPER ADAPTATION OF A TRUCK TRAIN TRANSPORT. IMPROVED HAUL ROADS, GREATER DISTANCES, AND INCREASED DEMAND FOR MINE PRODUCTS AT COMPETITIVE PRICES ARE RESULTING IN A RE-EVALUATION OF ALL COST ASPECTS OF MATERIAL MOVEMENT. THE TRUCK TRAIN CONCEPT USING RELATIVELY SMALLER TIRES THAN LARGE PIT TRUCKS OPENS THE DOOR TO REDUCED OPERATING COSTS BY LOWERING CYCLE TIMES AND COST PER MILE OF TIRES AND CAPITAL INVESTMENT. |
Analysis of 30 MPH Frontal Barrier Utilizing Half-Scale Metal Models | A cost-effective early indicator of frontal barrier performance relative to government and corporate goals has been provided by half-scale metal models. These models provide direct indications of steering column kinematics and performance of specific components with respect to the windshield intrusion zone. Some indications of fuel system integrity and windshield retention evaluations have been inferred from half-scale model barrier tests. Model tests have provided early standard barrier data on vehicle crush modes and distances, barrier loads, and deceleration rates, in addition to generating data beyond what is available in standard barrier tests. |
Rollover, Ejection, and the Potential Effectiveness of Restraints in Heavy-Truck Occupant Fatalities | Rollover and ejection are associated with heavy-truck occupant fatalities almost twice as frequently as with passenger-car occupant fatalities. A panel reviewed 41 in-depth cases to assess the possible effectiveness of restraint use and the contribution of rollover and ejection to the fatal injuries. The panel's responses indicated that belt use was expected to be particularly effective in preventing fatalities resulting from occupant ejection. A review of the proportion of ejections by model year indicated that 1972 model year and newer heavy trucks have about 20 percent fewer ejections than pre-1972 heavy trucks. Ejection through the doors was reduced by 80 percent. This difference seems to reflect the effectiveness of FMVSS 206, which required stronger door latches. |
The Basic Design of Two-Stroke Engines | This informative publication is a hands-on reference source for the design of two-stroke engines. The state-of-the-art is presented in such design areas as unsteady gas dynamics, scavenging, combustion, emissions and silencing. In addition, this comprehensive publication features a computer program appendix of 28 design programs, allowing the reader to recreate the applications described in the book. The Basic Design of Two-Stroke Engines offers practical assistance in improving both the mechanical and performance design of this intriguing engine. Organized into eight information-packed chapters, contents of this publication include: Introduction to the Two-Stroke Engine Gas Flow Through Two-Stroke Engines Scavenging the Two-Stroke Engine Combustion in Two-Stroke Engines Computer Modelling of Engines Empirical Assistance for the Designer Reduction of Fuel Consumption and Exhaust Emissions Reduction of Noise Emission from Two-Stroke Engines |
Case Studies Involving the Use and Non-Use of Seatbelts | This paper presents the case study results of several actual motor vehicle accidents which occurred in the western U.S. Each case was analyzed to determine the characteristics of impact to the vehicle and the resulting occupant injuries. The most frequent injury was facial laceration from impacting the windshield. The main benefit of restraint systems lies in their ability to reduce or prevent contact between the occupant and the interior during the crash. |
MF 60 TDL | This paper provides a brief review of some of the more significant features of the new Massey-Ferguson MF 60 Backhoe Loader. The machine incorporates a new “load sensing” hydraulic system and a low noise cab. These features together with the basis for its structural design are reviewed. |
A History of Headlining | This paper describes the history of the design and method of installation of cut-and-sew headlining and how it is affected by the design of the body beginning with the all-wooden construction of the first Chrysler up to the present day design. Construction of the headlining listing seam, the drafting procedure for determining their location and trim off around the window and door openings is described. |
A Modular Cab for Farm Tractors | This paper discusses the design of the modular cab for the White Farm A4T tractor. The modular concept creates new problems in cab and tractor design and has a significant effect on tractor assembly line operations. The cab is particularly quiet and well sealed. Data regarding operator noise levels are presented with comparisons shown to similar products and recent legislative activities in the area of noise control. Operator environmental control is improved with the modular concept, and performance data and specifications are discussed. The end product is the result of a close cooperative effort by the tractor manufacturer and cab manufacturer brought forth by the need to provide the customer with a greatly improved cab. |
A Balanced Approach - A Lawyer's Viewpoint | Laws controlling noise and the role of various local, state and federal agencies must be balanced against their respective interests, limitations of technology and environmental goals. Past attempts to control noise sustain the need for a balanced approach. The interest of obtaining realistic, uniform standards which are enforced by realistic, uniform procedures will advance the cause of noise control. Inconsistent standards and enforcement procedures will only impede effective noise control. |
Control of Diesel Engine Exhaust Noise | The contribution of exhaust noise to total vehicle noise is identified by isolation and near field techniques. Control of exhaust noise by using the principles of absorptive, reactive, and dispersive mufflers and their combinations is examined. Guidelines are presented to help the engine designer in the selection of mufflers within the design limitations of size, weight, and engine performance loss. |
Establishment of Roof Rail Sealing Parameters for Automobile Bodies | The reduction of sound levels in modern automobiles has called attention to wind whistles in the body side sealing systems. Methods employed to establish sealing design parameters are reviewed and the primary cause of wind noise in the body side sealing system is defined as a loss of glass-to-weatherstrip contact, produced by door glass “blowout” in vehicles traveling at highway speeds. A program of controlled dynamic testing resulted in design parameters that have produced body side sealing systems which, together with improved assembly techniques, have increased the first test-run wind noise acceptability rate for 1970 model year vehicles. |
Minimum Noise Pod Design | The necessity for realizing a major reduction in community noise from that produced by the current air transport fleet was recognized at the inception of the design of the Lockheed L-1011 Trijet wide-bodied transport. This paper summarizes the technical considerations and design procedures used to ensure attainment of the low-noise objective. It is shown that the Rolls-Royce RB.211 engine selected for the L-1011 incorporates the latest state of the art noise reduction features, including the novel shaft-slowing provision. These features result in a significant reduction in basic noise level compared to low by-pass ratio engines currently in service, even at the considerably increased size required for the L-1011. The additional noise reduction required to satisfy the low community noise objective and the FAR Part 36 limits is attained by incorporation of advanced noise suppression materials into an efficient propulsion pod design. The technology, design restraints, and system requirements which must be combined into the practical optimum minimum noise pod design are described. |
An Ultrasonic Leak Detector for Automotive Field Service | A wind noise, dust, and water leak detector has been developed for use in the automotive dealership service environment. The detector effectively indicates the precise location of leaks and presents a quantitative indication of the magnitude of the leaks in any body compartment. The new kit embodies a unique application of advanced ultrasonic detection techniques by employing an ultrasonic source and an ultrasonic detector. The device is inexpensive, relatively simple to operate and results in a significant reduction in the manhours required to detect wind noise, dust, and water leaks in automobiles. |
The Case for V/STOL Aircraft in Short-Haul Transportation | The case for a VTOL transport system is presented primarily against the background of European requirements, based on the use of fast low noise fan lift V/STOL aircraft. The main benefits are: 1. Passenger and airline appeal - time saving, convenience, competitive fares. 2. Community acceptance - reduced noise, reduced proliferation of large airports. 3. Operational advantages - flexibility, enhanced all-weather operation, safety and ATC. 4. Reduced investment - on a total system basis. The fan lift formula leads to a wide range of V/STOL aircraft to meet worldwide STOL, V/STOL, and VTOL requirements, with excellent long-term development prospects. |
Legal Aspects of Military Sonic Booms | Sonic booms from aircraft are a relatively recent phenomena. However, the law has developed to meet the new challenges and old rules of liability have been modified to fit the changed conditions. The following paper is an attempt to show some of the legal developments which have resulted from military supersonic flight, since only military or government type aircraft have flown supersonically in the United States to date. Various theories of liability for sonic boom damages have been considered by the courts and these are set forth in this article for comparison purposes. From a review of these decisions, we may be able to anticipate how future courts will handle similar problems. |
Earthmoving Equipment Cab Design | The history of the development of enclosed cab design is discussed. The advent of mechanical power meant that attention could be given to making the equipment operator more comfortable with respect to seating, work space, air conditioning, and visibility. These items are discussed, along with the improvements in rollover protection and noise control. |
On the Noise Reduction of a Rectangular Box with Application to Tractor Cabs | The mechanisms by which airborne sound energy is transmitted into a vehicle cab are discussed. Airborne noise reduction of cabs is seen to deviate considerably from the masslaw behavior of the constituent materials. Various acoustical treatments are evaluated experimentally by directly measuring the noise reduction on a cab-like enclosure. The experimental results agree fairly well with available theoretical methods of computing noise reduction. |
Wax Method of Determining Windshield Defroster Performance | This paper describes a procedure for determining defroster performance using wax. The approach is a useful tool for establishing breakthrough points, and developing balanced defroster air distribution patterns prior to cold room testing. Since it can be conducted at room temperature, the wax method is considerably more convenient and can be executed with greater frequency than in a cold room. Although the wax procedure is a good barometer of the relative effectiveness of different defroster systems, and does provide valuable preliminary studies, it does not duplicate cold room conditions. The test method described, therefore, is not a substitute for, nor can it be used in place of, actual cold room testing. The paper provides information on the test facility, test equipment, test preparation, wax mixture and application, and conducting the test. |
The Objective Method of Evaluating Aspiration Wind Noise | The automobile industry places a major emphasis on reducing car interior noise levels to attain a more pleasant and comfortable ride. In recent years, improved superhighways, allowing higher car speeds, have created a rise in the aspiration wind noise due to high aerodynamic pressure differentials causing air to pass by the body seals. No longer is a car body sealed merely against water leaks. With the increased use of air conditioning in cars, the closed side windows have lowered the ambient interior noise, thereby exposing the broad band frequency aspiration wind noise. A need for an objective method for the quality control and development of body seals was imminent. This report analyzes the aspiration wind noise parameters and presents two objective methods of measuring aspiration wind noise. These methods, using a meter, replace the previously used method of subjective evaluation of the loudness of wind noise. |
Rear Axle Noise Quality Inspection Method | For many years axle plants have needed a practical testing method for rating the noise quality of rear axle assemblies before installation in cars. This report describes the development of such a test method. Creation of noise requires an energy source. The energy source of rear axle noise is the periodic variation in tooth meshing action of the gears. The frequency of axle noise is always related to tooth mesh frequency. A previous study of rear axle gear dynamics indicated the existence of a nearly vertical resonance of rear axle pinions excited by tooth meshing action. The dynamic resonant amplitude of the motion of the pinions related directly to the in-car noise quality of the gear sets. In general, other resonances within the drive line-axle housing-suspension system can be excited by gear action and produce “axle” noise. An indication of the amplitude of the resonant member (or another responsive member within the system) directly relates to the relative noise quality of the gear set. To verify this relationship, the dynamic pinion response of a group of 30 axle assemblies was measured. The in-car noise ratings were obtained by using a jury of three experienced raters. The correlation between the dynamic pinion motion measured in a test stand and the in-car noise ratings was found to be very good, indicating the feasibility of using this method in axle plants. A statistical analysis was made of the data to determine the degree of correlation and the validity of the data. Details of the test stand operation, noise rating method and tests results are included in the report. |
The Uniflo Personal Rapid Transit System | A personal rapid transit system has been developed, capable of providing urban areas with public transportation service that is competitive with the automobile in speed, availability, accessibility, and comfort. The system contributes no pollution in terms of air, noise, or vibration; it is relatively small in size; and it can be installed elevated, on grade, or below grade. These qualities make it an acceptable addition to a community. Because this personal rapid transit system is highly automated, a significant reduction in the amount of labor required to provide transportation service is anticipated. This could mean that it would again be possible to make money moving people. |
A North European Tractor Cab | A farm tractor protection cab made of thin steel sheet pressings is described. The cab is designed and produced using entirely automotive-type procedures. Curved glasses and a dampening suspension of the glasses are found to be an important means of achieving a low noise level in the cab. Using the pressing technique when producing a steel cab makes it possible to give the various cab details rigidity with a minimum of material. When welded together, these details form a very stiff cab body, which gives the necessary mechanical strength. The curved surfaces, the radii, and the round forms, which from a tooling point of view are natural for pressed steel parts, also have a vibration-dampening effect on the entire cab construction, thus making it easier to design a quiet tractor cab. Mounted on a farm tractor of conventional design, the cab meets the noise rating number ISO N85. |
Door Crashworthiness Criteria | A study of the biomechanical factors concerned with the design of side structures and doors for crashworthiness has been made. Questions regarding optimum stiffness, location of reinforcing members, effect of armrests, and padding have been answered within the framework of injury criteria models. Results of animal studies, cadaver studies, and anthropometric dummies have been combined to produce injury criteria for lateral impacts to the head, thorax, and abdomen. Impacts were applied utilizing a specially designed “air gun” in a laboratory environment emphasizing reproducibility and control. Full-scale crash simulations were performed on an impact sled to verify the results of the more specialized tests and analyses. Scaled models of current production doors were used in the animal series. Scaling relationships for various species of animals have been developed and extrapolated to man. Significant differences in right and left side tolerances to impact were noted and detailed. Additional verification of the Maximum Strain Criteria Model (MSC) is reported. Critical impact velocities for various body sites have been developed for several categories of impact and are presented in ways thought to be most meaningful to designers. |
Automotive Safety in Review | This paper broadly surveys the continuing research and development by automotive engineers in designing safer automobiles. Door latch redesign, seat belts, energy absorbing steering columns, laminated windshields, energy absorbing instrument panel and its knobs and levers, dual brake systems, seat back impact absorbing tops, head restraints, and bias-ply tires are among the improvements discussed. Passenger restraint remains the most important factor in saving lives, however, and the public has been careless in using such systems. Passive restraints, such as the air bag, are under development. The need for good driver training programs, the problem of alcohol, and the need for continuing improved highway design are also touched upon. |
Power Plant Design for Noise Suppression | The design configuration of turbofan power plant installations for commercial aircraft is significantly influenced by the requirement for reduced aircraft noise. This paper describes the design evolution of the installation of the CF6, high-bypass ratio engine in the McDonnell Douglas DC-10 as it was influenced by the need for noise suppression measures. The candidate alternatives and the basic trade-off criteria leading to the selected configuration are presented. This paper also includes some considerations associated with choice of material, construction, and design techniques applicable to various areas of sound treatment within the nacelle. |
Noise Considerations in the Design of Advanced Subsonic Transport Turbofan Engines | The problems and choices in the design of an advanced subsonic transport turbofan for reduced noise and improved aircraft performance are examined in this paper. The effects of bypass ratio, fan pressure ratio, and fan tip speed on jet noise, fan noise, and acoustic treatment suppression are described. The results do not indicate a clear optimum bypass ratio considering the effects upon installed engine performance and weight as well as acoustic performance. Low fan tip speed designs with the associated high aerodynamic loading are compared to high tip speed low loading designs. Other factors affecting noise such as the installation and other noise sources are discussed. The long duct installation is indicated to have potential advantages over the short duct separate flow installation. The problem of assuring that growth models of an engine also have low noise is discussed. |
Airtransit's First Six Months of Operating The Canadian STOL Demonstration Service | A complete STOL (Short Take-off and Landing) system is currently providing public transportation service between the urban centres of two large Canadian cities. Passenger and public reaction, plus operating experience in a competitive environment is providing some interesting data, useful in developing future STOL systems as an important component in the improvement of transportation in general. The Demonstration is showing that STOL systems are capable of quickly providing fast, convenient, short-haul service, while at the same time respecting the composite concerns of society, encompassing air-pollution, noise, land-use, energy-consumption and economics. |
Planning, Implementation, and Operation of the Philadelphia-Lindenwold Line | Through careful planning and implementation the Delaware River Port Authority has developed a highly successful mass transit system, the Philadelphia-Lindenwold Line. They have realized their goal of creating a rapid transit line which would win the patronage of potential passengers and be constructed and operated within the economic resources of the Authority. The one to six car trains are operated by a one man train crew who is, in fact, part of the automated or computerized process. He notifies the computer as to the length of the train; opens and closes doors; determines the length in time of each stop; initiates acceleration; and can eliminate station stops. The computer prevailing determines train speed for each track section and right of way conditions; causes the train to decelerate at the optimum rate; and stops at the station with the center of the train at the center of the platform. The Lindenwold Line has demonstrated that motorists will leave their cars if superior transportation is provided; quality transit service can reduce air and noise pollution and conserve energy; traffic congestion can be reduced; technology is now available to create desirable rapid transit service, and that rail rapid transit can be planned, constructed, and efficiently managed to meet operating and maintenance costs out of the fare box. |
NASA REFAN PROGRAM STATUS | The objective of the refan program is to demonstrate the technical feasibility of substantially reducing the noise levels of existing JT8D powered aircraft. The program consists of the design, manufacturing and testing of the refan engines and modified nacelles and airplanes. Experimental testing has been completed for the refan engine both at sea level and at altitude conditions. Ground testing for the B727 side- and center-engine installations and flight testing of the DC-9 with refan engines and acoustic nacelles have been performed. Analyses of the test results are in progress. Preliminary results presented in this paper show that substantial noise reductions were achieved. |
A Technique for Measuring Interior Wind Rush Noise at the Clay Model Stage of Vehicle Design | A technique has been developed to evaluate interior wind rush noise during wind tunnel tests of full-size clay models of vehicles. A small, box-like enclosure with acoustic characteristics made similar to those of a typical vehicle interior is inserted into the clay model behind an actual front sideglass. The wind rush noise coming through the sideglass is directly measured by microphones located within the enclosure. The technique can readily detect wind rush noise changes due to body modifications in the vicinity of the windshield-pillar. In addition, the wind tunnel results agree well with those found on-road. |
Interior Noise Problems of Small Diesel-Powered Buses | This paper discusses interior noise problems characteristic of the combination of diesel engines with typical small bus geometries. One noise problem is the potential for low-frequency resonances. Natural air vibration modes for typical small bus interior dimensions are calculated and shown to give frequencies that can be stimulated by noise and vibration at engine firing frequencies. Measurements of noise and vibration at resonance are given. Other noise problems are associated with internal front engine covers, and leaks and low transmission loss paths in the console area. Some practical suggestions, with examples, are given to reduce interior noise. |
Application of Microprocessors to the Automobile | This paper describes microprocessor technology as it may be applied to the automobiles of the future. The microprocessor requirements described in this paper were generated as a result of the evaluation of the Alpha IV vehicle system which utilizes a solid-state, digital 4-bit, microprocessor to perform several vehicle control and display functions. The development of the Alpha IV system encompassed not only the interface circuit design and microprocessor programming, but also, the derivation of the digital algorithms and control laws for the functions which have traditionally been performed in an analog fashion. The control functions performed include: Cruise Control, Four-Wheel-Lock Control, Traction Control, Speed Warning, Speed Limiting, Ignition Spark Advance and Dwell, Automatic Door Locks, and Anti-Theft System. The display functions include: Speedometer (both analog and digital), Odometer, Trip Odometer, Tachometer, Clock, and Elapsed Time. |
The Rovac Automotive Air Conditioning System | The ROVAC air conditioning system, a new system that employs air as the refrigerant, is a combination rotary compressor/expander unit. A prototype has been modeled, designed, fabricated, laboratory tested, and field tested in a full size four door 1973 Dodge Coronet. The description of the new system, the analysis, design and actual test results are reported here. The objective of the engineering program was to demonstrate and prove the capability of the ROVAC system to effectively and efficiently air condition automobiles. The prototype system installed in the Dodge Coronet produces delivered cooling capacity on the order of one to one and a half tons per thousand rpm and has produced delivered coefficients of performance at relatively high humidity levels (150-180 grains water per pound of dry air) rivaling the best developed conventional vapor compression air conditioning systems. While the present system reported herein has not reached the levels of performance predicted by detailed computer models, continued hardware improvement is facilitating actual performance very near the levels predicted to be practically achievable. During actual in-car jury tests, the prototype ROVAC air conditioning system brings the average passenger compartment temperature from a thermally soaked condition of 107°F down to 72°F in less than two min with five passengers at an average road speed of 30 mph. |
Evaluation of Two Convex Mirror Systems by Government Drivers | A nationwide field study of two types of convex mirror systems was made by the National Highway Traffic Safety Administration (NHTSA) with the cooperation of the General Services Administration (GSA) for a 10-month period starting in January 1974. One convex mirror system, called the Type I system, consisted of a non-adjustable convex mirror on the right fender, the original outside mirror on the driver's door, and a larger inside mirror. The Type II mirror system consisted of an adjustable convex mirror mounted on each fender and the original inside rearview mirror. A total of 515 Federal employees evaluated these two convex mirror systems at six major test locations to provide 627 questionnaires. An analysis of the questionnaires shows that drivers preferred the Type II convex mirror system over the Type I. From comments received, it seems that the drivers objected mostly to the non-adjustable feature and restricted field of view of the Type I system rather than to the fact that it was only a one-convex mirror system as compared to a two-convex mirror system. However, neither convex mirror system was rated as highly as the periscope system was evaluated in a previous field test of 50 periscope equipped GSA automobiles (1)*. This suggests that drivers would prefer unit magnification mirror systems with larger rearward fields of view over convex mirror systems with roughly the same view; nevertheless, drivers also prefer the convex mirror systems tested over conventional mirror systems because the convex mirrors provide greater rearward visibility. |
Acoustic Performance of a Large Semi-Anechoic Test Chamber | This paper describes a large indoor semi-anechoic facility for testing construction machines and discusses the procedures used to determine its acoustic performance characteristics. Data were obtained and analyzed employing controlled pure tone and broad band noise sources with varied microphone distances and elevations. The ground-plane microphone proved to be the most practical way to obtain representative data. Comparisons to an outdoor test site are included. |
J58/YF-12 Ejector Nozzle Performance | The Lockheed YF-12 aircraft uses a blow-in door ejector nozzle, which consists of a variable area, primary nozzle mounted on the afterburner of a Pratt & Whitney Aircraft J58 engine and blow-in doors, a convergent-divergent spool piece, and variable exit area free-floating flaps integrated into a Lockheed YF-12 airframe. Performance data from cold-flow, wind tunnel models and hot-flow, static stand models were correlated and compared with actual flight test data. It was found that these data showed agreement when both internal thermodynamic and external aerodynamic effects were considered. |
Environmental Guidelines for the Designer of Automotive Electronic Components | This paper describes the climatic, dynamic, and electromagnetic environments in which electronic packages must survive at various locations in the automobile. Previously available climatic data is organized to be useful to the designer. New dynamic information that provides power spectral information for various locations on the automobile is presented. The electromagnetic information includes power line transients, voltage regulation, and steady-state noise information. |
Design of Elastomeric Vibration Isolation Mounting Systems for Internal Combustion Engines | The Internal Combustion engine, by nature a dynamic vibration source, requires a properly designed flexible mounting system to isolate those disturbing vibrations. To do this it is necessary to consider all six degrees of freedom of the engine and to use the computer to determine vibratory outputs for given inputs. An example of such a computer program is given. In addition, the design of a mount system requires consideration of static and dynamic force resistance and reduction, motion limitation, environmental resistance and service life requirements. Elastomeric mounts can provide substantial noise reduction but due to the complexity of the noise problem, the prediction of the actual amount of reduction is more of an art than a science. High frequency problems caused by “standing waves” in an elastomeric mount are very much less likely to occur than those due to structural resonances. Examples of noise reductions due to the addition of elastomer mounts, on some actual vehicles, are given. |
Safety Performance of Securiflex Windshield | An improved windshield with a special, thin, plastic inner surface attached to the inner surface of a three layer windshield similar to those used in the United States minimizes lacerations from occupant impact to the windshield during a collision. The plastic coats the sharp edges of the broken glass preventing or minimizing laceration. It was evaluated by comparing its laceration performance with that of a standard windshield in simulated barrier crashes at velocities up to 65 km/h. No lacerations resulted from impact to the Securiflex windshield at Barrier Equivalent Velocities up to 65 km/h. Substantial laceration resulted at velocities above 20 km/h with the standard windshield. It is concluded that the Securiflex windshield essentially eliminates lacerations in the particular vehicle involved at velocities up to at least 65 km/h. |
Less Noise From Diesel Trucks | An indepth study to reduce noise produced by a typical highway diesel truck is being conducted to determine levels and costs attainable by practical means. Truck noise reduction involves isolating several individual noise sources, that is, fan, exhaust, engine-radiated, intake system, and others, and developing means to reduce each. Tire noise and major engine revisions are not considered in this project. Goals of 78 dB(A) (per SAE J366a) without engine enclosure and 75 dB(A) with engine enclosure are believed possible on the vehicle configuration being studied. This project is sponsored by the U.S. Department of Transportation Office of Noise Abatement, and industry. |
Propulsion Integration for a Hybrid Propulsive-Lift System | In a discussion of STOL vehicles with conventional high-lift devices, the need for efficient power-augmented lift systems is presented and the implications of quiet operation are noted. The underlying philosophy of a promising hybrid lift system with major interactions between aerodynamic, thermodynamic, acoustic, and configuration design technologies is derived. The technique by which engine and airframe-related characteristics for this application may be matched in an optimum manner is described and illustrated by describing the features of a particular short-haul commercial STOL vehicle. |
Human Engineering Applied to the Design and Grouping of Electrical Controls in the Motor Vehicle | A study has been made of motor vehicle driver environment in order to determine the most desirable design features and the optimum grouping of electrical controls conducive with minimum conscious thought and physical effort in location and operation under any given set of conditions. Consideration is given to the psychological aspects of control operating noise level and action “feel,” to styling and standardization of layout with the ultimate objective of driver fatigue reduction, and to a worthwhile contribution in road safety improvement. |
Sound Attenuation in Operator Enclosures | This paper outlines parameters for the design of operator's enclosures (cabs), with special reference to noise control. Specific suggestions for the solution of noise pollution include shock mounting of the cab, plugging all holes through which noise can enter, attenuating large sheet metal areas by damping, effectively using large amounts of glass, diverting the exhaust outlet away from the cab, providing a fan shroud, not mounting sound generating components to enclosure walls. Such steps should reduce the sound level by 15-20 dB, but will add 12-15% to the overall cost of the enclosure. |
Interior Window Fogging - An Analysis of the Parameters Involved * | Many factors are directly related to the occurrence of window fogging and flash fogging. The pertinent variables affecting the problem are identified and discussed. In simple terms, fogging is dependent upon the difference between the dew point temperature of the interior environment and the glass surface temperature. Several dew point and glass temperature curves have been computed which typify various operating conditions. Alternatives that will help to eliminate fogging are discussed. |
New Methods of Reducing Noise in External Gear Pumps | The noise from external gear pumps has been significantly reduced by a new design which consists of two sets of gears, half the width of a standard gear, and offset about 1/2 pitch. The new pump makes use of a housing which is externally basically the same as a standard pump. This paper presents test stand and field measurements of the pump. |
Advanced Olympus for Next Generation Supersonic Transport Aircraft | The paper summarises the background studies which have led to the proposal for an advanced Olympus engine, with mechanical noise suppression, to power the next generation supersonic transport aircraft. The recent international collaborative test programme on real engine scale ejector suppressors is described and reference is made to other Rolls-Royce experimental work at model scale. The envisaged changes to the design of the in-service Concorde engine are outlined and some installation aspects are discussed. It is emphasised that detailed refinement of the engine cycle must depend on the result of aircraft/engine integration and optimisation studies. |
Bulldozer Noise Control | Bulldozer noise is the most serious noise problem for surface miners today. Not only are bulldozers the most common type of mobile equipment, but the majority of their operators are also exposed to more noise than current federal regulations allow. In 1977, the Bureau of Mines responded to this problem by developing retrofit noise control treatments which reduce the noise that reaches the operator. These treatments were specifically designed to be readily installed in the field at low cost. In 1978, these treatments were installed on two Caterpillar D9G’s in surface coal mines to demonstrate the noise reduction that can be achieved under actual production conditions. This paper presents the results of the field demonstrations. |
Side Impact Sled and Padding Development | IN A ONE YEAR LABORATORY STUDY, a side impact sled was designed, built, and validated. Using the sled and a newer generation of side impact dummy, a number of energy-absorbing materials were tested and superior materials identified. Initially this study concentrated on the crash test data for a number of V.W. Rabbits crashed in a previously completed study. The crashed vehicles were obtained, and interior crush tests were performed with a specially designed body form. This was done to determine how the effective stiffness (as seen by the occupant of the struck vehicle) of the interior door increases as the bullet vehicle presses against the interior door trim from the opposite side. An acceleration-type sled buck was then designed and built with an “interior door” mounted to mimic the interior stiffness determined from the crush tests. The sled was dynamically tested with a Haversine sled pulse similar to the door crash pulse. The sled was validated by reproducing the crash environment of a car-to-car collision. The criteria considered for matching the two were: (1) acceleration-time curve of the interior door, (2) the velocity-time curve of the interior door, (3) kinematics of the Part 572 surrogate, and (4) accelerations on the surrogate. |
Evaluation of Pelvic Fracture Tolerance in Side Impact | Pelvic fracture is a typical lesion sustained by the occupant of a vehicle involved in a lateral impact collision who is seated on the impact side. If this fracture is generally not severe by itself, it is nevertheless often associated with severe abdominal lesions. Study of injury mechanisms in lateral impact collisions shows that there are two ways of ensuring a better protection of the occupant in this type of accident: first by preventing intrusion so that the contact velocity “occupant/inner door” is decreased, secondly by absorbing the shock of the occupant against the inner door, especially at pelvis and thorax levels. It is necessary to have a good knowledge of human tolerance to fracture of the considered body segment in order to determine the mechanical properties of the padding material. The aim of this study is to determine the tolerance of the human pelvis. This study takes into account results of 36 impact tests against the pelvis of 10 cadavers and proposes injury criteria values to characterize the risk of pelvic fracture. |
Vehicle Design Considerations For Older Drivers | During the next half century, the older driver population will increase dramatically as the Baby Boom becomes a Senior Boom of similar proportions. Therefore a proper understanding and awareness of the changes that take place in our vision and cognition through aging, can be useful to engineers designing automobile systems for a more mature market. How these changes brought about by aging affect our interaction with such vehicle systems as controls and displays, mirrors, head-lighting, seating, and entry and exit is the subject of the following discussion. Recommendations also are made, based upon the current literature, for modifying these vehicle systems to meet the needs of older drivers. |
Physical Characteristics Of Heat-Absorbing Glass And Their Influence On The Driver | The characteristics of heat-absorbing glass for passenger cars are described with regard to climate perception and visibility of the driver, both of which are important aspects of active safety. Such modern types of glass reduce the transparency to heat and at the same time maximise light in the visible spectrum. To be in a position to quantify the advantages and disadvantages in the visible spectrum as regards transparency, dazzling, reflectance and diffused light, practical road-test runs were carried out on the same public roads under different conditions in light and climatic environmental. The tests comprised physico-technical, physical and psychological data with regard to driving behaviour of and strain on the drivers. The results confirm the predominance of advantages of heat-absorbing glass and provide, indications as to optimising the side and rear windows by increasing the degree of heat-absorbing. |
Investigation of Vehicle Side Impact Stiffness - Comparison of Static and Dynamic Tests | The purpose of this investigation on vehicle side-impact stiffness and the comparison of the static and dynamic tests was to contribute guidelines for a final test procedure with two advantages: to be, on the one hand, simply practicable and reproducible and, on the other hand, to provide results corresponding as close as possible to real accidents. Additionally, the investigation emphasized testing of side parts significant to the objectives of the test: door only, door and sill, or door, sill and roof. New cars as well as heavily rusted vehicles were used for the test. Therefore this paper also treats the question of what degree a test of only new cars will be useful, without considering the state of corrosion of older vehicles. |
A Study of the Vehicle Acoustic Control for Booming Noise Utilizing the Vibration Characteristics of Trunk Lid | An acoustic control technique for reducing booming noise caused by road surface roughness is described. This noise, mainly in the frequency range between 25 and 40Hz and accompanied by a pressure sensation, is closely related to suspension vibration characteristics and the acoustic response of the vehicle compartment. A reduction method which separates the highest acoustic response from suspension resonance in this frequency region is proposed. An acoustic simulation model is used to estimate the effects of the luggage compartment on this noise and of trunk lid vibration characteristics in optimizing acoustic properties of the compartment. As a result, a frequency region for trunk lid resonance which lowers booming noise is obtained. Estimated booming noise reduction is experimentally confirmed in road tests. A study of human auditory characteristics is also conducted to ascertain the frequency range and booming noise level which produce uncomfortable sensations. |
Prevention of Frost Formation on Automobile Glazing | Energy radiation during clear mornings causes a temperature drop on outdoor surfaces. If this drop is big enough, moisture will condense and lead to frost formation during cold weather. This is a nuisance and a safety risk for the driver when it occurs on car windows. If the surface of the glazing is coated so that the emissivity within certain spectral bands is low, frost formation can be prevented in most situations. In the autumn of 1986, Volvo introduced a windshield on these lines. Tests indicate that the number of mornings when scraping is necessary is reduced by more than 80% in the Swedish coastal climate. |
Special Considerations in Outfitting a Space Station Module for Scientific Use | This paper addresses some of the key issues involved with outfitting a space station module for life sciences research, namely the integration of a large diameter centrifuge for holding control specimens at 1G (or fractions thereof); accommodating international participation in the design and construction of key elements of the lab module (including the module itself); and maintaining biological isolation between the experimental animals and the crew. Several design concepts are presented that address these specific issues. Centrifuge vibration - once thought to be a major problem in a station that also houses materials technology experiments - will be virtually eliminated by the use of an active magnetic suspension and automated rotor balancing. Bioisolation is provided by housing the animals in special isolator cages and performing all experimental work in a laminar flow isolation hood. |
Performance Criteria for Speakers in Digital Car Audio Systems | In an automotive sound system, the environment plays a major role in the total acoustical performance. Most of the design goals are the same as in home entertainment systems. However, the presence of road noise and restricted space availability for the speaker location must be considered as design criteria. High excursion requirement to overcome the masking effects introduces several nonlinearities. Since cars behave differently under dynamic conditions, speakers must be designed selectively for high performance. |
Machine Vision Correlation to Master Gauges | Machine vision technology is a tool being utilized in the new GMT-400 pickup truck Body Shops for process monitoring and control. These real-time Machine Vision Dimensional Gauging systems monitor 100% of the production's critical build features such as door and window openings, hinge locations, and fender mounting brackets, Traditional gauges typically can provide data on only a small sample of production −1% or less. Correlating the machine vision systems to master gauges allows accurate data to be collected on every job as it is being built. This complete dimensional control data provides information for process monitoring as well as a means to detect tooling adjustment requirements and the ability to detect build problems, even if they occur intermittently. Several methods of performing this correlation have been investigated, with the goal being to define a correlation procedure that works well in the plant environment. |
Study of the Hydrodynamic and Viscoelastic Properties Affecting the Surface Appearance of Extruded EPDM Compounds | An experimental study was aimed at understanding the mechanisms establishing the surface appearance of extruded EPDM compounds for applications where aesthetic appearance is critical. The study shows that surface appearance is directly proportional to the extent of viscous heating in the die, and hence can be controlled by the degree of shearing action, either by screw and die design or screw speed. Both surface appearance and extrudate swell can be related to the viscoelastic properties of the EPDM polymer through the dimensionless Deborah and Euler numbers. Knowledge of the parameters affecting surface appearance can be applied to better design of EPDM polymers for such applications as automotive seals for windows and doors, which are comprised of both dense and sponge extruded profiles. |
A Body Switching System using the SAE J1850 (CarLink) Protocol | The recent approval by the SAE Motor Vehicle Council of the serial protocol J1850 is a major milestone in the development of an open and flexible network approach to vehicle wiring. However, it is now necessary to evaluate the practical implementation of the protocol in some real vehicle applications. This paper describes one such exercise which considers a three station installation including the doors and a central body computer function, together with a diagnostic capability. It is, of course, anticipated that this simple system will be extended to include other areas of the vehicle as confidence is gained in its performance and the benefits of system integration are realised. |
Numerical Simulation of Air and Heat Flow in a Heater Unit | Heat flow phenomena in the heater unit of an automobile air conditioning system have been analyzed by direct simulation, solving the Navier-Stokes' equation in which an upwind finite difference method of third-order accuracy is adopted with a 2-D model. The analytical results presented visually to ascertain air and heat flows in the heater unit. In addition, a comparative experiment was carried out to compare test results with calculated results. The heater unit in the air conditioning system controls the temperature of air in the automobile. The heater unit consists of a unit inlet, outlet, mixing door and heater, as shown in Fig. 1 (1). Air, entering the heater unit inlet is mixed with warm air heated by the heater to a suitable temperature, and then blown out of the outlet. The shape and size of the heater unit are restricted by the size of an automobile's engine compartment and the layout of other auxiliary devices. Therefore, warm air must be mixed with cool air efficiently in this limited space. The shape of the heater unit has been determined based on experience. The development of the heater unit requires a fairly long period of time and much labor. To improve the efficiency of this development process, the authors quantitatively analyzed air mixing phenomena in the heater unit. The Navier-Stokes' equation was solved directly by the third-order accuracy upwind method. |
A Low Cost Door Control System | The ability to achieve a low-cost replacement for the conventional wiring harness is difficult when considering a multiplexing system designed for a minimum wire count. This paper looks at a specific problem - getting a large number of cables across the ‘A post’ into the driver's door, and considers the issues affecting the design of partially multiplexed solutions. A summary of the technical and cost implications of the new system is included. |
Electrochemical Metallizing, Tooling Design, and Application | Electrochemical metallizing (ECM) has been widely used in aircraft maintenance and OEM applications, but is far from reaching it's potential. Although ECM has been around for more than twenty years, it still represents a small part of metal finishing as a whole, thus making information describing the process not readily available. Most of the problems experienced with the process, aside from solution contamination, stem from improper tooling design, and will be the focus of this paper. Tooling and other areas covered will be as follows: 1 Anode design: choosing proper anode design for the job. 2 Flow-thru anodes: for more efficient distribution of electrolytes. 3 Precision build-ups: plating to size. 4 Solution and anode cooling: to prevent over-heating of solutions at the anode/work-piece interface and the effects on the deposit. 5 Masking techniques: how to make the tape work for you by reducing high and low current density problems. 6 Heavy build-up: depositing .050″ or more. This paper will cover areas which help us get closer to creating ideal ECM conditions, therefore improving repeatability and opening doors to new applications. |
Fabrication of Interior Door Trim Using Ceramic Dies | To produce high quality appearance interior parts, precise pattern forming or gloss reduction of three-dimensional door trim cover materials are utilized. In the preparation of formed trim cover using polyvinyl chloride (PVC), prior pattern forming on original cover material or post-pattern forming with vacuum forming dies are employed. In the latter case, the die is usually made of epoxy resin. Although vacuum holes are prepared on the resin die as necessary, the lack of uniformity in air permeability causes inferior pattern transferability. In this development, special porous ceramic die is used as die material so that trim cover material can be evenly sucked through the fine pores on its surface. As a result, a door trim forming die of superior pattern transferability has realized. The features of this- die are as follows. 1) The addition of metal powder, metal fiber, and binder to the ceramic powder has achieved well balanced air permeability, compressive strength, and dimensional change rate. 2) The uniform, high air permeability can produce deep and precise grain and stitching pattern (patterns) transfer with a low surface gloss rate. A work area with a stable surface quality can also be secured. 3) A shorter lead time of manufacturing and lower die making cost have achieved. |
A Steel-Plastic Hood Concept for Passenger Cars | A novel hood of steel and plastic has been designed to achieve an effective balance between weight and cost. The design concept uses a thinner (lighter weight) 0.024-inch-thick steel sheet for the outer component and a compression molded SMC inner component combined with an inner very thin (0.015-inch-thick) steel sag pan. Cost estimates of the hybrid hood were made using a mathematical cost model developed by MIT and indicated costs similar to an all-steel hood, but significantly lower than for an all-SMC hood. In addition, the weight of the hood is less than the all-steel hood. The steel outer optimizes the surface characteristics of the hood and maintains appearance compatibility with other exposed steel body panels. The inner steel sag pan is used in membrane tension to work with and complement a minimal weight SMC panel. The inner SMC portion also acts in compression and bending to significantly limit panel deflections and greatly increase the assembly's stiffness. Key adhesive bonding tests were successfully conducted with bare and coated steel substrates selectively bonded to SMC during the SMC molding cycle. The encouraging engineering analysis of the novel hood and the attractive combination of low weight and cost suggest that similar benefits could be derived from combining steel and plastic in other two-piece assemblies (deck lids and doors). |
Development of Practical Multiplexed Wiring System | This paper describes a new approach to solving various problems inherent in conventional multiplexed wiring systems. These problems include the fact that the quantity of cut leads, which determines the cost, is not reduced even though the bulk of the wire harness is decreased. Another problem is that the communications system has a very complex configuration. With the approach proposed here it has been found that the number of cut leads can be reduced by housing the communications circuits individually in each piece of electrical equipment. This can be accomplished by grouping together the wiring in which the signals activating electrical load units all flow in the same direction. Custom LSI circuits have been developed to simplify the communications circuits. All of these developments have been combined into practical multiplexed wiring systems for controlling the power Windows, automatic door locks and power seats. |
Energy Management of Thermoplastic Composites in Automotive Instrument Panels/Components: An Option for FMVSS 208 | Federal requirements for unrestrained occupant protection, recent automotive designs requiring increased part integration and modular assemblies, high costs for tooling and secondary operations, and intensifying competition are primary incentives for automotive engineers and designers to consider thermoplastic composite materials for replacing and complementing many current metal parts. Nowhere is the scrutiny of material choice more significant than in parts where energy management and stiffness are major design concerns; parts such as bumper beams, door structures, seating, and instrument panel components. Thermoplastic composites offer designers materials which are lightweight, perform consistently over wide temperature ranges, and manage energy to meet part performance requirements. |
An Integrated Door System Using Multiplexing | Many separate door systems are integrated into a single functional system that uses multiplexed wiring techniques. This system shows advantages over conventional techniques in many areas. Some of the advantages are: Reduced wiring, less part numbers, reduced car-to-car variability, increased functions, better build, and better servicing. |
Door Module of Polyurethane: A New Concept | This is a specification for a car door made of polyurethane plastics with the following features: Door body of GF/PU combined with an integrated metal support. The outside door panel from the waist line down to the bottom edge of the door is fixed to the door body with an adhesive-bonded joint. A metal support designed as a stiffening frame and a supporting element for fittings. Permanently bonded, form-fitting window combined with multi-purpose window that can be lowered. The costs show that this concept is able to compete with conventional metal solutions. |
Ten Years of Plastic Applications in Fiat Car Exterior Components: Review and Preview | The paper outlines the evolution of the plastic component in Fiat passenger cars as far as the outerpart is concerned. A first section is devoted to bumpers and their evolution into front and rear ends where different materials (thermosetting and thermoplastic ones) and finishing procedures (grained in-mass pigmented or smooth and painted) were adopted. Further the evolution of a rear door is quoted dealing with the design concept of two wall adhesivated structure and with the selection of the appropriate manufacturing technology. In conclusion, taking also care of the service performances, trouble shooting and technology evolution during the last ten years, some considerations are quoted, demonstrating that the approach to fully plastic body panels will require in each case peculiar studies and development works. |
Car Occupant Ejection in 919 Sampled Accidents in the UK-1983-86 | Vehicle and injury data from 919 accidents in the UK are analysed for frequency, cause, and consequences of occupant ejection. Injury consequences are shown to be severs, the fatality rate rising with ejection by a factor of 4.3 among unrestrained occupants, and evidence is offered that ejection prevention would reduce injury levels to those of not-ejected occupants. The rear window was found in this sample to be the most frequent ejection route, followed by side doors, side glass, and the tailgate. Complete ejection was slightly more frequent from hatchbacks than from saloons. Door openings are analysed for frequency and release mechanism, and the ejection risk for exposed occupants is seen to be very high. These results are considered in relation to possible countermeasures, of which restraint use is shown to be by far the most effective, and bonded laminated or glass-plastic glazing is particularly recommended for rear windows. |
New Developments in Materials and Fabrication Processes for Automotive Interior Trim Skin Materials | Automotive interiors consist of sandwich type components (e.g., instrument panel, door trim, headliner); hard trim (e.g., pillar trim) and functional solid components (e.g., load floor, seat backs, etc.) The intermaterials competition among new processes for fabricating these 3 types of components were described previously (1)*. This paper examines new developments specifically in the area of skin materials used for the sandwich type interior trim components. |
A Survey of Vehicular Side Wall Constructions | Starting with the vintage flat built up side wall constructions in the form of door and quarter trim panel trim, this paper discusses the resinated felt, wood fiber, filled plastic extruded sheet, injected molded, molded in place, reinforced reaction injection molded (RRIM), structurally reinforced reaction injection molded (SRIM) side wall constructions. It further discusses cover materials for interior trim in the United States, Europe and the Orient. The future trends along with modular doors are discussed. A conclusion is made regarding the responsibility to be undertaken as assigned by the end using customer. |
Application Study of Vibration Damping Composite Steel Sheet to the Car Body Panels | The vibration damping composite steel sheet was improved in properties such as dependence on temperature, bending rigidity, press formability and spot weldability and compared with damping materials currently used by reviewing composition and adhesion strength of the resin and the mechanical property of the steel skin sheets. By applying the above-mentioned materials to the floor and wheel-house panels, a reduction in noise and vibration was obtained in the application test, and improvement in door shutting noise was also revealed when applying these materials to the door panels. |
Relationship Between the Physical and the Psychoacoustic Parameters of the Sound Field in an Automobile | A new method of measuring physical factors that prescribe the sound field of the vehicle interior has been used to evaluate the differences in the sound field for 4 types of two-channel loudspeaker systems, which are installed in the front part of the vehicle. The physical property which prescribes the sound field inside the vehicle is related to the directional properties of the sound, such as lateral, forward and backward component of the early reflection sound energy. Psychological experiments have also been conducted under the same conditions as that for the physical measurement, and then the correlation between the psychological factor and the physical factor has been examined. The following conclusions have been reached: (1) L/M (the ratio of low frequency sound energy vs. medium frequency sound energy) is highly correlated with spatial impression. (2) F/B (the ratio of forward directional energy vs. backward directional energy) greatly contributes to the preference of the sound quality. (3) L/R (the ratio of left directional energy vs. right directional energy) is highly correlated with the localization (left and right) of the sound image. (4) Among the four types of two-channel loudspeaker systems, “mounted in the front doors” has a wide sound image and is more preferable in comparison with the other loudspeaker locations. |
Status and Update of MVMA Component Testing | At the Tenth ESV Conference, MVMA reported on the development of a component side impact test device developed for MVMA by MGA Research Corporation. Since that time, the test device has been modified by MGA to improve its biofidelity. Testing has shown that the modified device better meets the force-time corridors derived by MVMA from cadaver drop test data. The improved test device was used to test twelve 1985 Ford LTD doors at speeds of 25.7 and 37 km/h. The interior door surfaces were trimmed with either thin fiber board or foam padding identical to doors in vehicles tested by MVMA using NHTSA's full-vehicle test procedure. The tests showed that the MVMA device is simple to set up and run, is highly repeatable and easily discriminates between the unpadded and padded doors. A major issue for future research and development is how to select a priori a component test device impact speed which can account for differences in car size and side structure stiffness. |