Display:

Results

Viewing 9631 to 9660 of 11057
1971-02-01
Technical Paper
710576
C. W. Floyd
Laboratory power loss test procedure and effect of varying conditions on power loss is discussed. An attempt is made to correlate laboratory rolling resistance with fuel economy. The information is presented from the perspective of a tire engineer, with the objective of providing useful information to automotive designers as well as other interested parties.
1971-02-01
Technical Paper
710590
R. H. VanSteenkiste, E. K. Buyze
This paper discusses The Budd Company's development of a new and novel approach to an old product. It involves the design, development, and manufacture of a brake disc for an automotive disc brake using materials other than cast iron. This product must have all the qualities of a cast iron disc, but must be competitive price-wise. The development of a solid disc would have been a relatively simple challenge; however, a ventilated type disc complicated the task by requiring a composite or welded structure. Real ingenuity in design and material processing was demanded. The results are what is called the Budd “All Steel Brake Disc.”
1971-02-01
Technical Paper
710589
Frank H. Highley
Heat storage, heat dissipation, and cooling coefficients are defined; and equations, based on theory and practice, are developed with which values of the coefficients can be determined. Vehicle tests required are described. Use of the coefficients in predicting drum or disc temperatures is demonstrated, using coefficient values obtained in vehicle tests. Use of the cooling coefficient for simulating brake cooling on a brake dynamometer is demonstrated.
1971-02-01
Technical Paper
710527
Rolland D. Scholl, Richard E. Klein
A steering system for an articulated vehicle was analyzed to gain an improved understanding of the closed loop stability characteristics. The analysis was applied to an electrohydraulic system and is applicable to more general types of systems. Since the parameters of electrohydraulic valves are well known, a simulation model including the hydraulic system and the vehicle dynamics, was easily derived. Using the simulation, the oil mass resonance was determined to be the most critical parameter and was controlled by adding compensation in the steering system closed loop. The paper describes the steering system, simulation model, and stability criteria.
1971-02-01
Technical Paper
710529
Thomas E. Cochran
Caterpillar Tractor Co. has introduced a new emergency-parking brake system for its line of large wheel loaders and wheel type tractors. This system includes a multidisk-spring-applied/hydraulically-released-emergency-parking brake, a hydraulic control system providing both automatic and manual application of the brake, and an audiovisual warning system for the operator. The brake is for use on vehicles in the 60,000-140,000 lb range and is designed specifically to provide automatic application of the emergency-parking brake in the event of a loss of service brakes.
1971-02-01
Technical Paper
710530
Lon B. Eberhart
The steering and braking systems used on the all-hydraulic JD-570 articulating grader were designed with the safety of the operator in mind. These systems are given priority over the other related hydraulic systems on the grader through the use of a priority valve. An accumulator is provided to store hydraulic energy for the steering and braking systems in the event of a power failure. In addition, the brake valve is capable of acting as a pump to supply pressure oil to the service brakes, if required. A mechanically actuated secondary brake effective on all four tandem wheels is also provided.
1971-02-01
Technical Paper
710536
Giles A. Kendall
A compressible solid shock isolator is a combination spring and damper which makes use of a silicone elastomer media to achieve these two functions. It is a candidate for use in energy absorbing bumper systems because of its favorable volume, weight, automatic reset capability, functional efficiency, reliability, and cost. E/A bumper systems must be designed to accommodate a wide variety of loading conditions. System qualification requires the use of both pendulum and barrier type testing.
1971-02-01
Technical Paper
710534
Robert G. Moore
Many factors, including vehicle motion, temperature, humidity, atmospheric contamination, and noise level, influence the habitability, or ride comfort, of any vehicle. All of these factors must be considered in the design of an air cushion vehicle (ACV). This paper discusses the motion of the craft induced by traveling over a rough surface. This motion may be reduced by suitable design of the lift and skirt systems, to minimize pressure changes within the cushion.
1971-02-01
Technical Paper
710627
Yasuhiko Fujiwara, Miki Nakayasu
An analysis was made of vibration phenomena in the steering system of a vehicle, when the front wheels have some amount of unbalance. The program included vehicle running tests and bench tests to ascertain some of the factors influencing vibration behavior. A mathematical model of the vibration system was simulated on a digital computer in as much detail as possible. The resultant understanding of the dynamics of the system as a whole led to an extensive theoretical analysis of selected key parameters.
1971-02-01
Technical Paper
710626
N. Seitz, A. W. Hussmann
Of all the automobile safety studies made, one that has received much attention is tire design. Comfort, service life, and reliability have been the guideposts in the development of better and safer tires. The investigation of the forces that affect reliability is the subject of this paper, and emphasis is placed on determination of the parameters at the particular area where tire and road are in contact.
1971-02-01
Technical Paper
710630
Walter Bergman, Harold R. Clemett, Narendra J. Sheth
This paper gives a comprehensive analysis of tire-road traction, utilizing new experimental and analytical techniques. It introduces a concept of traction envelope for evaluation of the overall tire traction properties in all operating modes on a common basis. It establishes feasibility of laboratory techniques for tire wet traction measurements and shows good correlation between road and laboratory measurements and also between road measurements on different surfaces. Comparative evaluation between new and conventional techniques for measuring tire traction on the road in cornering with and without power application are given.
1971-02-01
Technical Paper
710615
O. Webb
Preventing loss of vehicle control under drive conditions is analogous to, and as important as, the retention of vehicle control under emergency braking. Loss of control under drive conditions frequently leads to panic braking, which only aggravates an already dangerous situation. A four-wheel-system for passenger cars is described, having as its special aim greatly improved controllability under all road surface conditions. Reasons are given for splitting the torque unequally between the front and rear axles, and for employing two spin control clutches geared in parallel to the center differential in such a manner as to modify the basic torque split.
1971-02-01
Technical Paper
710165
George M. Kurajian, Harold Burr
A general analog computer procedure is presented for the dynamic analysis of a selected realistic model of an automobile or truck vehicle wheel-frame system. The elements of the model are assigned a set of values based on a preselected vehicle, and the model is then subjected to a number of inputs which correspond to test track road disturbances at various speeds. This procedure is successively applied to a number of typical vehicles. Time-varying values of wheel spindle and frame reaction “g” loads, acclerations, and displacements are recorded, and illustrative waveshapes are depicted. Tables indicating extreme values of these quantities are also included.
1971-02-01
Technical Paper
710388
T. Peter Neal
Control-system bobweights and downsprings are quite often used in general aviation airplanes to improve longitudinal static stability at aft c.g. positions. However, these devices can also have strong and usually undesirable effects on the airplane's dynamic behavior. These important effects are reviewed and discussed. In addition, guidance is provided as to how some of the undesirable characteristics can be minimized by careful design.
1971-02-01
Technical Paper
710400
Don McCosh
Aircraft produced by Cessna have, for a number of years, used steel landing gear springs as the major portion of the aircraft main or tail landing gears. These steel springs are relatively simple in design and manufacture, and have proved to be durable. This paper discusses some of the factors involved in the design of a spring steel landing gear, analysis methods, and design goals used at Cessna. Certification requirements and methods of compliance for landing gears are also discussed. The analysis methods employed have been proved acceptable by the ability of the gears to pass certification tests without modification, and by service experience.
1971-02-01
Technical Paper
710360
B. L. Douglass
With the advent of increasing numbers of heavier passenger car-trailer combinations, the need for a uniform brake test procedure code and recommended level of performance requirements for such combination of vehicles became apparent. Initial efforts were directed toward a standard of performance for the trailer or towed vehicle brakes only, but as the work progressed a more practical solution evolved in a test code, SAE J134, and performance requirements, SAE J135, for passenger car-trailer combinations. It is intended that light trucks will be considered in a later revision.
1971-02-01
Technical Paper
710361
Raymond R. McHenry
A digital computer simulation of complex, three-dimensional dynamics of automobiles on irregular terrain is described which is suitable for studies related to vehicle braking systems and to the driving task, including the upper limits of control as well as the linear ranges of operation. The reported simulation is an extended version of an earlier, validated mathematical model. A number of refinements and extensions of the analytical treatments of tire forces, suspension properties, and terrain definitions, have been incorporated. Also, analytical representations of the braking system and driveline, and approximations of rolling resistance and aerodynamic drag, have been introduced. Sample outputs of the modified computer program are presented and discussed.
1971-02-01
Technical Paper
710287
J. Mahig
Knowledge of that component of a vehicle's handling characteristics represented by the vehicle dynamics is necessary to analyze the driver's role in controlling the vehicle. One aspect of this problem is determination of the effect on the stability under differing road conditions in the linear as well as nonlinear region. The simulation presented evaluates the response the vehicle suspension system to suddenly applied external impulses which are identified as caused by wind gust and road disturbance. This analysis considers only the effect on the lateral stability of the vehicle. Thus this representation is assumed completely decoupled from the longitudinal dynamics of the vehicle. Proceeding in this fashion makes it possible to study the effect of large wind gust and lateral road impacts on the lateral stability of a vehicle containing nonlinear tire characteristics. The effects in the nonlinear region are clearly demonstrated with the aid of a conventional root locus plot.
1971-02-01
Technical Paper
710252
P. W. Meyer
The paper attempts to give an overall view of the very complex brake fluid situation existing in Europe today. It is written with the hope of creating a better understanding of the actual realistic requirements that have to be set for modem and safe brake fluids. It is further hoped that it may help to pave the way for an international standardization of brake fluid specifications and test methods.
1971-02-01
Technical Paper
710253
R. W. Radlinski, R. J. Forthofer, J. L. Harvey
Automotive hydraulic brake fluids are known to pick up water in service. This paper shows that a major portion of the water picked up by the brake fluid in a braking system is transmitted through the hoses. It discusses two major effects of water pick-up on brake fluid performance-reduction in vapor lock temperature, and increase in low temperature viscosity. Performance data for several “wet” brake fluids operating in actual braking systems at high and low temperatures are presented.
1971-02-01
Technical Paper
710250
J. D. Preston, R. J. Forthofer
The frictional properties of brake lining materials are greatly influenced by the manner in which they are used. Test procedures designed to measure the coefficient of friction of these materials can likewise produce widely differing results depending on the type of test conducted. This paper presents data illustrating the performance correlation of three commercially available brake lining materials when subjected to vehicle tests and some of the more commonly used laboratory test procedures.
1971-02-01
Technical Paper
710254
Harkrishan Singh
The Kinematic Analysis Methods Computer Program that has been used by Ford Motor Co. to evaluate mechanisms for the past four years has been modified to generate performance curves for windshield wiper linkages directly using a Calcomp Plotter. Problems such as stalling, “jerky” operation, and excessive phase lag between wipers can be detected early in the design stages by careful evaluation of the curves.
1971-02-01
Technical Paper
710248
J. W. Douglas, T. C. Schafer
The paper outlines testing, development, and operation of the first production four-wheel slip control system for passenger cars in the United States. The Chrysler Corp. calls the system “Sure-Brake,” but it is more generally known as “anti-skid.” The first portion of the paper deals with considerations that led Chrysler into the Sure-Brake system, the philosophy behind the system, and a detailed explanation of its operation. The second portion deals with the development and testing of the system, leading to its release as an option on the 1971 Imperial. The testing program introduced a new dimension to brake engineering. Before the advent of wheel slip control systems, many thousands of brake tests were conducted but were always terminated at the point of skid. These tests were also conducted mainly on black top or concrete roads. For the first time, thousands of stops were made at maximum deceleration on every available surface.
1971-02-01
Technical Paper
710249
A. J. Wilson, G. T. Bowsher
Methods of testing brake linings by sample machine have been evolved to a standard of consistency which enables the performance of a brake to be evaluated by consideration of the geometry of the system and the coefficient of friction of the lining. This situation does, however, only hold if the way in which the lining is tested bears a close relationship to the duty cycle employed on an actual brake. In this paper the correlation between brake performance and estimates based on scale testing shows that a classification can be employed to simplify the choice of replacement linings when a single material is employed. Duo servo brakes are least amenable to this technique because of their high sensitivity.
1971-02-01
Technical Paper
710247
S. K. Rhee
A drag dynamometer was used to investigate the influence of rotor properties on the wear of automotive brake linings. The effects on lining wear of temperature, surface roughness, thermal conductivity, microstructure and composition were studied quantitatively, and the mechanisms governing lining wear were elucidated. Lining wear at high temperatures increases exponentially with increasing temperature, and decreases exponentially with increasing thermal conductivity of the rotor. The wear increases parabolically with increasing surface roughness of the rotor. Also, coupling of a lining with a rotor having compatible composition and microstructure is very important for controlling the lining wear.
1971-02-01
Technical Paper
710223
Howard Dugoff, R. W. Murphy
This paper reviews the state of theoretical and experimental technology relative to the dynamic performance of articulated highway vehicles. The review contains three major sections, corresponding to the traditional breakdown of vehicle performance: directional performance, braking performance, and combined directional and braking performance. An attempt is made to take a frankly evaluative point of view and to point out knowledge gaps and unanswered questions, in addition to documenting previous accomplishments and progress. The paper concludes with some recommendations for future research consistent with the findings of the review.
1971-02-01
Technical Paper
710222
Bruce D. Van Deusen
This paper describes a test program and computer simulation aimed at optimizing the riding qualities of a Military tractor semitrailer combination, the Heavy Equipment Transporter (HET). Instrumented testing at the U.S. Army Aberdeen Proving Ground was conducted with a variety of suspension configurations. The test data were recorded on magnetic tape and converted into digital data for computer processing. The test results were correlated with computer simulation. The computer model was then used to perform a sensitivity analysis of various suspension parameters. With rms acceleration at the vehicle frame used as a criterion for optimization, an improved suspension configuration was defined. The techniques for test data analysis and computer simulation are described and preliminary results are presented.
1971-02-01
Technical Paper
710230
I. R. Ehrlich, D. Sloss, B. Hanamoto, C. J. Nuttall
A novel design in which the wheel of a military vehicle is modified into an axial flow pump in order to provide improved forward propulsion is presented along with full scale experimental data and concept evaluation.
1971-02-01
Technical Paper
710227
Glenn A. Jackson, James W. Grant
A method for measuring spring rate and damping coefficient is necessary for complete laboratory evaluation of a suspension component. This report outlines a technique by which a linear model is adjusted by an analog computer so that its parameters match those of the test specimen. The accuracy of this linear model is good unless the test specimen parameters are very nonlinear. To determine how structural changes in a suspension unit affect the dynamic action of the unit, measurable suspension parameters must be defined. One set of parameters can be obtained by assuming that, for small angular motion, a single suspension unit can be modelled by a parallel springer-damper combination. This system is completely defined by the two parameters spring rate, K, and damping coefficient, D. This paper outlines a method to measure K and D under laboratory conditions which simulate typical operational environment.
1971-02-01
Technical Paper
710225
G.B. HICKNER, J.G. ELLIOTT, G.A. CORNELL
An improved version of the seventeen-degree-of-freedom hybrid computer simulation described in Reference 1 is being modified to include a four-wheel adaptive braking system (ABS). The derivation and verification of the ABS model, the form of the integrated vehiclel/ABS model, and future plans for validation and utilization of the integrated hybrid simulation are presented.
Viewing 9631 to 9660 of 11057

Filter