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Viewing 164041 to 164070 of 190464
1974-02-01
Technical Paper
740625
W. J. Holt, R. W. Corey
Las Vegas, Nevada, is one of the ideal urban environments for a Personal Rapid Transit (PRT) System. The city operates on a “round the clock” basis and highway traffic congestion is becoming severe with the growth of tourism. The principal industry is tourism and a fare structure can be imposed which will make a PRT system self-supporting. A PRT system is described which meets the anticipated Las Vegas requirements of 24 h/day operation, vehicle and service being designed to compete favorably with the automobile. The PRT system elements described include vehicle, guideway, control features, stations, and maintenance facility. The results of a maintenance plan analysis and financial considerations are also discussed.
1974-02-01
Technical Paper
740623
T. A. Lancaster, D. L. Hearn
With the nation looking more and more to mass transit to solve its urban transportation problems, the innovative Personal Rapid Transit (PRT) systems with their “second car” characteristics can be expected to complement bus and rail services, especially in medium-density population areas. After summarizing the role each of these three forms of public transit plays and is projected to play by 1990, the paper describes current specialized PRT applications in the United States and abroad.
1974-02-01
Technical Paper
740604
Franklin B. Airheart
Various approaches to truck disc brake design are discussed. Design of the disc and the effect of its design on brake performance show current designs being proposed may be inadequate. Lining area must be adequate for long life without restricting cooling. Piston retraction and adjustment by mechanical means is more reliable than seal retraction. A multiple disc oil-cooled hydraulic disc brake can provide extended life and high torque in a small diameter package. Air-actuated disc brakes eliminate the need for hydraulics, but introduce problems in force multiplication and brake-to-brake balance.
1974-02-01
Technical Paper
740605
Tasuku Date, Shizuo Yagi, Akira Ishizuya, Isao Fujii
This paper summarizes some of the technical considerations upon which Honda's CVCC system is based, relating to reduction of pollutants in automobile engine exhaust gases. The CVCC engine employs a stratified charge to produce stable combustion of an overall lean mixture. A unique mixture is formed immediately before ignition to reduce three pollutants (CO, HC, and NOx) simultaneously, as well as to improve fuel economy. This mixture is produced by contolling fuel mixtures supplied to the engine and by geometrical combustion chamber design features. An evaluation model conceived by Honda to evaluate emissions and fuel economy during the driving cycle mode is explained, and a comparison of estimated values obtained from the evaluation model with those obtained under actual driving test conditions is made.
1974-02-01
Technical Paper
740607
G. R. Thurman
The sound level of crossbar-type truck tires was found to be only slightly affected by the texture of the portland concrete road surfaces used. Rib-type tires showed higher noise level on coarse than on smooth surfaces, but the ranking of different tires was unaffected. Clearance of the truck bed above the tire was relatively unimportant. Noise level increased with increase in speed. Sound persistence after truck passby is related to tread design and possibly to the radiation pattern from the road-tire interface.
1974-02-01
Technical Paper
740606
William H. Close
Based on the past research of the U.S. Department of Transportation, this paper is an attempt to make the case for tire noise regulation and to illustrate the implications of such regulations to tire users. The paper examines the effects of speed, load, tire tread type, road surface, and placement of tires on combination truck vehicles insofar as passby sound levels are concerned. A concluding table of expected roadside sound levels based upon typical tire use indicates the potential restrictions in tire types that are inherent in presently proposed federal noise regulations on interstate motor carriers. It is concluded that as significant technological improvements are implemented in the design and regulation of truck engine noise, more severe tire user requirements will follow in order that tire noise keep pace with declining engine noise.
1974-02-01
Technical Paper
740609
William F. Reiter, Allen C. Eberhardt
This paper describes the procedure and instrumentation used to telemeter, record, and analyze in-service truck tire accelerations. The tire sound signal monitored at a point approximately 1 ft to the rear of the tire was recorded simultaneously with the acceleration signal on board the test vehicle. Subsequent time domain, frequency domain, and level analyses of the signals show the importance and relationship of tire acceleration to the tire noise generated. The results reported are for a 10:00-20 cross-bar type tire with three states of wear, two load conditions, and three speeds.
1974-02-01
Technical Paper
740608
R. F. Miller, D. B. Thrasher
This paper discusses the importance of the spectral distribution of the energy in the sound to the dB(A) level of the usual passby test. A described technique obtains reproducible “real-time” spectra from the nonstationary sound field. Doppler effect and source frequency shift are quantified in relating these spectra to the tread pattern repetitions. Inverse square law fitting is viewed through the two-source-microphone relation which changes during the spectral window period. Spectra are shown for 6, 12, and 50 ft (1.83, 3.66, and 15.2 m) passby microphones and for a microphone carried on the truck.
1974-02-01
Technical Paper
740615
Rudolf G. Mortimer
Differences in characteristics between automobiles and trucks, such as driver eye height and headlamp mounting height, were examined, as well as roadway vertical and horizontal curvature and meeting beam patterns and lamp aim. Effects of these variables were evaluated by a computer simulation of nighttime meetings on a 2-lane road. The visibility distance and direct and indirect (mirror) glare discomfort effects were measured. Results suggest that: low beam headlamps on trucks should not be mounted at more than about 36 in (0.91 m) from ground level, the increase in visibility provided by the mid beam is less for truck drivers than those of automobiles, the mid beam is less affected by vertical aim variations than the low beam, the mid beam should be extinguished by the vehicle in the inside lane on curves when meeting other vehicles and when following another vehicle at less than about 200 ft (61 m).
1974-02-01
Technical Paper
740614
John Voevodsky
A deceleration warning light system installed on taxicabs in San Francisco for 12.3 million miles of normal on-road driving reduced the rear-end collision rate by 60.6% compared to the rate for a concurrent control group of cabs which traveled 7.2 million miles. Comparing the experimental group with the concurrent control group revealed that the warning light prevented 5.4 collisions per million miles, 1.02 cab driver injuries per million miles, and $643 of taxicab damage per million miles. An amber light was center mounted on the rear of several hundred taxicabs and was designed to communicate information about the taxi's deceleration to following drivers.
1974-02-01
Technical Paper
740597
Romas B. Spokas
This paper presents a discussion of the modulating fan clutch which was chosen as a fan speed regulating device to improve the overall efficiency of the internal combustion engine. Generally the engine cooling system is oversized for normal operating conditions. With a fan speed regulating device providing the exact amount of airflow to maintain proper engine cooling temperature, the horsepower not required to turn the fan can be utilized for increased speed or fuel economy. This device also serves to reduce noise as the fan is one of the major contributors to this problem. Design goals and types of mechanisms considered are presented along with results of component and system testing of the modulating fan clutch.
1974-02-01
Technical Paper
740598
Jim Hanks, Charles Selby, Philip Loken
This paper discusses bearing arrangements designed to maximize stability and load capacity within available envelope dimensions. Also presented is a means of negating the detrimental effects of cylinder reactions in a pneumatic clutch, while at the same time increasing the torque-to-space ratio. These concepts were realized during a study expressly intended to view the various design elements with the requirements of a diesel truck fan clutch in mind. Further, the study resulted in the development of a nonmodulating, direct acting thermal control valve, specifically engineered to complement the action of a pneumatic fan clutch as part of an overall temperature controlling system.
1974-02-01
Technical Paper
740595
Keith A. Boyd, Jim Easterly
A method for measuring diesel fuel consumption accurately over short distances of 5 miles or less was developed so that many fan-on, fan-off data sets could be gathered in a short time for statistical evaluation and analysis. A second test sequence involved fan-on, fan-off fuel economy tests over a highway route for comparison against the Cummins Vehicle Mission Simulation Computer Program. The predicted results from this program agreed substantially with the actual highway economy test data we obtained. More than 4 million charted miles of roads throughout the world are available through this program for predicting fan-off fuel savings. Results on several typical routes are given.
1974-02-01
Technical Paper
740596
Everett G. Blair
Both the advent of the energy crisis and the regulation of noise levels are making fan drives highly desirable for heavy truck applications. This paper evaluates the reduction of power drain and fan noise for two types of fan drives generally available today: the on-off air-activated clutch and the modulated viscous drive. In addition, the principles of operation, life, and application considerations are discussed.
1974-02-01
Technical Paper
740603
S. L. Stokes
This paper outlines various laboratory tests which can be utilized to evaluate heavy truck disc brakes. The methods described include supplemental techniques derived from improved dynamometer procedures which assure that the brake components and assembly will perform the intended function and that a practical and effective design has been obtained. They ensure that the brakes will provide the “toughness” required in the “real world” environment.
1974-02-01
Technical Paper
740602
W. T. Birge, K. H. Rinker
Disc brakes for trucks have been the subject of intensive investigation in the United States since their adoption on passenger cars and light trucks in the mid 1960s. Although the basic industry work has covered the full range of medium and heavy hydraulic and air-braked trucks, the first commercial use of heavy-duty calipers will be on the front axles of heavy air-braked trucks where their stability and high torque characteristics are of particular advantage in meeting FMVSS 121, scheduled as of this writing to become effective March 1, 1975.
1974-02-01
Technical Paper
740599
R. T. Johnson
In light of the probable shortage of liquid petroleum fuels in the United States for the foreseeable future, much attention is being focused on possible fuels as substitutes for conventional gasolines and distillate-type fuels. This paper surveys the presently available synthetic or substitute fuels being considered for transportation uses. The survey includes a brief review of current energy use patterns in the transportation sector and a projected future for the automobile and other transportation modes. Specialized fuels needs for the transportation sector are described including attributes of the ideal fuel. Discussion of possible synthetic fuel candidates is broken down into categories-hydrocarbons, hydrogen, inorganic hydrogen compounds, and electrochemical systems-and general properties.
1974-02-01
Technical Paper
740600
John Houseman, D. J. Cerini
A compact onboard hydrogen generator has been developed for use with a hydrogen-enriched gasoline internal combustion engine. The unit uses gasoline and air in a partial oxidation reactor to produce a gaseous product containing hydrogen, carbon monoxide, minor amounts of methane, carbon dioxide and water, and nitrogen. A study of the theoretical equilibrium product composition has indicated an optimum operating point at an air/fuel ratio of 5.15, where a hydrogen/fuel mass ratio of 0.136 can be obtained under soot-free conditions. This is based on a gasoline with an atomic hydrogen to carbon ratio of 1.92. Both thermal and catalytic reactors have been tested. The thermal unit requires a reaction temperature of 2400°F to obtain 80% of the theoretical hydrogen yield. Soot formation tends to be a problem. The catalytic reactor yields close to theoretical yields at an operating temperature of 1800°F without any soot formation. A commercial nickel catalyst is used.
1974-02-01
Technical Paper
740588
Raymond F. Neathery, Harold J. Mertz, Robert P. Hubbard, Mark R. Henderson
Two Highway Safety Research Institute (HSRI) dummies were tested and evaluated. Based on the analysis given, the HSI dummy should not be used for vehicle qualification testing. However, many of its components offer viable alternatives for future dummy development. The dummy was found to have inadequate biomechanical fidelity in the head, neck, and chest, although its characteristics were very promising and, as a whole, biomechanically superior to the Hybrid II. Its repeatability and reproducibility in dynamic component tests were better than the Hybrid II dummy. In particular, the HSRI friction joints were outstanding in repeatability and had a significant advantage in usability in that they do not require resetting between tests. In three-point harness and ACRS systems tests, the values of injury criteria produced by the HSRI dummy were generally lower than those obtained with the Hybrid II, especially the femur loads in the ACRS tests.
1974-02-01
Technical Paper
740589
R. L. Stalnaker, D. Mohan
Serious injuries are caused to the chest and thoracic organs both in front and side automobile collisions, and statistical surveys indicate that overall chest injuries are the third most frequent after head and the lower limbs. For safer design of restraint systems and vehicle interiors experimental data has to be obtained to establish chest injury criteria. Unembalmed human cadavers were used to conduct nine frontal and fourteen lateral impacts including four with a simulated arm rest. All impacts used a six inch (15.2 cm) diameter impactor with impact velocities ranging from 12 mph (19.3 kph) to 20 mph (32.2 kph). Chest impacts were also conducted on rhesus monkeys and baboons to establish primate-human injury scaling criteria. Four human volunteers were used to obtain static load deflection curves in the lateral and frontal directions. The results of the above experiments and those conducted by other investigators are presented and analyzed.
1974-02-01
Technical Paper
740586
B. Samuel Holmes, George Sliter
The utility of scale model experiments for crashworthiness research is examined. In Part I, two examples illustrate the use of scale models in crashworthiness research. The accuracy of modeling is shown by direct comparison between a model experiment and the test of a complete automobile in high-speed impact. It is concluded that scale models can be used in place of full-scale experiments for many applications. The comparison of hydraulic and plastic deformation energy absorbers in scale model experiments demonstrates the ability of models to reproduce the response of a wide variety of vehicle elements. In Part II, the cost effectiveness of scale modeling is measured by comparing the costs of full-scale experiments with scaled experiments that meet the same objectives. The comparisons include both individual tests of various types and complete vehicle development programs.
1974-02-01
Technical Paper
740587
Acen Jordan
This paper deals with the design concepts and development of a sled test compartment which exhibits yaw and pitch displacements as a function of the applied sled deceleration pulse. It outlines the program in which it was developed and notes the qualitative differences encountered when testing with these additional motions as opposed to testing with a fixed sled compartment.
1974-02-01
Technical Paper
740593
Arthur C. Haman
Paper describes three collegiate automobile runs sponsored by American Motors Corp. to demonstrate that savings in fuel are possible when good driving practices are observed. Driving 1974 Gremlins, the young winners proved that “typical” drivers can in fact achieve economies in fuel of the kind that are being sought nationally at the present time. Reduction of speed proved to be a major contributing factor.
1974-02-01
Technical Paper
740594
Robert C. Stempel, Stuart W. Martens
In 1968, a major oil company cancelled its annual automobile economy run after sponsoring it for 18 consecutive years -presumably due to lack of interest from the public and the press. Almost coincident with that cancellation was the beginning of production automobile exhaust emission control on a national basis and a downward inflection in the historic trend of automobile fuel economy. In contrast, the past year has seen a major revival of interest, by both the public and the press, in fuel economy. In the next few weeks, the nation will be introduced to a new direction in automotive exhaust emission control which will profoundly affect the fuel economy trend. Perhaps equally, or even more important, the next few months are expected to see major national decisions on future automobile emission control which will likely have a significant influence on the direction taken by automobile fuel economy a few years hence.
1974-02-01
Technical Paper
740590
J. A. Tennant, R. H. Jensen, R. A. Potter
The development, manufacture and testing of a new anthropomorphic test dummy (GM-ATD 502) is discussed. Improvements in performance repeatability and reproducibility of the dummy are documented and the anthropometric and biomechanical basis of the design described. The development of repeatable testing procedures and of dummy features that enhance the accuracy of the initial test setup are also discussed.
1974-02-01
Technical Paper
740592
Thomas C. Austin, Karl H. Hellman, C. Don Paulsell
The use of fuel economy data from the Federal Test Procedure (FTP) has provided a substantial amount of data on the fuel economy of passenger cars in urban driving conditions. Since the FTP does not represent the type of driving done in rural areas, especially on highways, a driving cycle to assess highway fuel economy was a desirable supplement to the FTP. The new Environmental Protection Agency (EPA) “highway” cycle was constructed from actual speed-versus-time traces generated by an instrumented test car driven over a variety of nonurban roads and highways. This cycle reflects the correct proportion of operation on each of the four major types of nonurban roads and preserves the non-steady-state characteristics of real-world driving. The average speed of the cycle is 48.2 mph and the cycle length is 10.2 miles, close to the average nonurban trip length.
1974-02-01
Technical Paper
740581
Juichiro Takada
Seat belt systems can be considered as the most convenient and practical system for occupant protection in automotive crash situations. Takata Kojyo Co., Ltd. has been striving to design and create a seat belt system that would be both practical and effective in absorbing impact energy with no injury in high speed crashes. In our search for more effective seat belt systems, we have conducted various comparison tests between conventional webbings and our newly developed webbing in regard to rheological property. 1. In regard to the dynamic performance of the webbing, the quantity of absorbed impact energy and the rate of absorbing energy were obtained and compared through tests at various impact speeds. 2. Dummy tests were conducted in our laboratories to compare the improved Takata energy-absorbing (EA) webbing with conventional webbing. The results showed the conspicuous superiority of the Takata webbing over the conventional types. 3.
1974-02-01
Technical Paper
740580
Charles E. Strother, Richard M. Morgan
This report presents an overview of the Occupant Packaging research program within the National Highway Traffic Safety Administration. The report discusses the program's efforts to establish the feasibilities of practical methods for providing the highest levels of occupant protection. In the area of frontal impact protection, work is progressing on advanced driver air bag systems, on a bag and bolster approach to passenger protection, on the development of improved inflation techniques for inflatables and on the passive application of the air belt concept. Efforts in the other areas of side, rear, and rollover protection are discussed as are NHTSA's efforts in child restraint research.
1974-02-01
Technical Paper
740579
Thomas H. Glenn
The Research Institute of NHTSA has been conducting dynamic sled tests of advanced and/or passive belt restraint systems for compact or subcompact cars. Phase I tests using dummies have been completed for eleven systems which were submitted by six different manufacturers. Test results are reported. Phase II tests using volunteer human subjects are now in progress for systems which generated good performance data during Phase I tests. The results of human tests of the first system have been very encouraging. Successful injury-free tests of one volunteer subject have been completed with a maximum attained velocity of 30.4 mph (48.9 km/hr) at an acceleration level of 21.1 G. Only the results taken from “quick-look” preliminary data are reported. Suggestions are made for additional research, development, and test efforts to optimize the performance characteristics of future belt restraint systems and to improve their comfort and convenience.
1974-02-01
Technical Paper
740585
T. O. Jones, W. A. Elliott
Design validation of crash sensors in the vehicle barrier impact environment is difficult and costly. The objective of this paper is to outline a method of developing optimum crash sensor mounting utilizing reduced-scale physical models. This technique incorporates design tools that are readily accessible during early vehicle concept stages which will allow mechanical impedance checks of the crash sensor to vehicle structure interface at significantly lower cost than full size prototype testing. Basic equations and methodology are presented with experimental correlation data.

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