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Viewing 164191 to 164220 of 190402
1974-02-01
Technical Paper
741068
J. A. Russell, S. J. Lestz
Experimental results with a 25-hp charge-cooled rotary combustion engine are presented for a variety of lubricant base stocks and additive packages. A rating method which combines endurance and deposition level is described. Lubricant performance is evaluated based upon this rating scheme, and contribution of base stock and additive package components is analyzed.
1974-02-01
Technical Paper
741075
Peter Lefferts
A monolithic integrated circuit has been developed that is a sensor, a voltage reference, and an operational amplifier, all in a simple four-lead package. Although the circuit is designed to sense absolute temperature as a physical parameter, certain application techniques allow other inputs to be handled. Differential temperature, position, and air velocity can be converted to analog, on-off, or frequency outputs as desired. Specific examples are provided.
1974-02-01
Technical Paper
741076
Mohan Dutt
Platinum resistance sensors are currently used for continuous service from -260°C to +800°C and up to 1200°C for short term use. The historical development of resistance sensors is discussed and the advantages of using platinum resistance sensors over thermocouples is described. Parameters used in the evaluation of platinum sensors and signal conditioners are enumerated. Errors encountered in temperature measuring schemes and methods to reduce these errors are summarized.
1974-02-01
Technical Paper
741100
Shunji Tsuchiya, Tadakiyo Watanabe, Yoichi Matsuoka
This paper discusses the cornering characteristics during the progress of tire wear and how the stability and controllability of a vehicle varies in the various stages of tire wear. With the introduction of tire parameters appropriate to represent the characteristics of tire construction, the method of calculation of the cornering characteristics of a tire is proposed in this paper. Furthermore, this paper shows the values of tire parameters in the various stages of tire wear in both cases of bias belted and radial tires.
1974-02-01
Technical Paper
741101
F. Celeri, A. Chiesa
The report starts by outlining some concepts regarding the forces and the moments which act on a tire. Some general characteristics of indoor cornering force machines, along with their limitations, are then examined. This is followed by a detailed description of a method of measuring tire-vehicle curves on a steering pad. The method, based on experience obtained by the use of mathematical models, permits a quantitative evaluation of the stability and the steering of a vehicle under steady state working conditions, on both wet and dry tracks. It is also shown that certain aspects of the vehicles behavior in transient conditions may be deduced from the data obtained. The method is valid for both cars and two-axle trucks and it is illustrated with some examples.
1974-02-01
Technical Paper
741096
R. W. Topping
A simple, linear vehicle model is presented which incorporates the most important characteristics of contemporary passenger cars. It is a three mass model with a fixed, inclined roll axis and linear suspension geometric and compliance characteristics. Basic concepts of understeer and oversteer are presented. Static and dynamic requirements are examined, yielding expressions relating the car's design to tire lateral load transfer, total lateral force, and turn radius. Turn kinematics give expressions for the front steer angle and sideslip angle. Suspension geometric and compliance effects describe the rear steer angle, tire inclination angles, and steering wheel angle divided by the overall steering ratio.
1974-02-01
Technical Paper
741105
Bernd Richter
Earlier VW driving simulator studies showed the relationships among subjective driver judgement, objective parameters and a vehicle parameter TB. The present series of tests was run to determine the effects of the steering ratio iLK with combinations of this parameter TB. The driving task was more difficult than those in earlier studies: the test subject tried to avoid suddenly appearing obstacles. This made it possible for the test subjects to become involved in critical situations, and for conclusions to be drawn from review of the potential accident sequence, as influenced by the vehicle parameter TB and the steering ratio. The report then presents examples to illustrate the effects of tire parameters and load parameters on the vehicle parameter TB, in a variety of different vehicles.
1974-02-01
Technical Paper
741104
R. L. Leffert, P. M. Riede, R. E. Rasmussen
There are many ways to describe the factors contributing to the directional control dynamics of motor vehicles. The cornering compliance concept is particularly applicable to the tire intermix situation since it helps to separate the front and rear contributions to total vehicle performance. The relationship between cornering compliances and vehicle response properties, discussed in previous papers, is reviewed. The contribution of tire mechanical properties to cornering compliance is described. Typical compliance levels associated with intermix of generic tire types, wear states, and brands are listed.
1974-02-01
Technical Paper
741103
Kenneth G. Peterson, Fraser D. Smithson, Fredrick W. Hill,
1974-02-01
Technical Paper
741102
S. A. Lippmann, K. L. Oblizajek
The paper presents data showing the effects of the state of wear, structure, load, and inflation pressure on the cornering stiffness and aligning torque stiffness of typical passenger tires. A method is introduced and applied for assessing contributions of local elements of the tread interface to the cornering force, the cornering stiffness, the aligning torque, and the aligning stiffness. There is also a further identification of the contributions to the aligning torque from fore and aft interfacial stress distributions and from lateral stress distributions. Pneumatic trail is redefined in the light of the interfacial measurements, and values are established for various operating conditions, states of wear, and tire types.
1974-02-01
Technical Paper
741089
K. C. Tsao, D. Losinger
This paper reports the mass-burning rate in a rotary combustion engine. The mass-burning rate is calculated through an iterative constituent and energy constraints during the combustion process. First approximation is obtained through the firing and motoring-pressure trace as recorded by an image-retaining oscilloscope and recorded subsequently by a polaroid camera. Effect of engine load, engine speed, relative (A/F) on the mass-burning rate and maximum heat release rate were studied. Three different type of fuels were used in the experimental test runs.
1974-02-01
Technical Paper
741091
G. A. Paul
Rotary engines, by design, are somewhat more difficult to cool than conventional reciprocating powerplants. This arises in apart from the fact that all four cycles do not take place within the same physical portion of the engine. The basic aim of this research was to study the metal temperatures of many points in the rotary engine with standard and experimental coolants in an attempt to develop a product with superior heat rejection properties in a conventional cooling system. The engine used for the experiment was a two-rotor liquid-cooled Wankel engine obtained from a 1972 Mazda R-100. Both road and chassis dynamometer evaluations were run over a wide range of operating conditions to obtain a comprehensive look at coolant performance. The parameters studied for each coolant were road speed, engine load, coolant concentration, and ambient temperature; the coolants tested were ethylene glycol, water, and the experimental coolants XA-1318L and XA-1318.1L.
1974-02-01
Technical Paper
741085
J. W. Douglas
In order to predict vehicle brake performance, calculations are made to determine the size of brakes, wheel cylinders, proportioning valves, and metering valves to give the desired results. To achieve this, basic data are required of brake torque output versus brake force input. This requires that a large amount of test data be accumulated from both dynamometer and vehicle tests to obtain the coefficient of friction of disc brake linings and brake factors for drum brakes. All the data available has to be presented in a meaningful form that can be understood with a minimum of study. This report deals with gathering of test data, brake balance calculations, and presentation in a graphical form by means of the IBM 1130 computer and graphing system.
1974-02-01
Technical Paper
741086
Rudolf Limpert, Franco E. Gamero, Ron Boyer
Most motor vehicles operating on our highways today are designed to exhibit high levels of straight-line braking performance without providing sufficient stability during combined braking and steering maneuvers. A basic engineering analysis is presented that allows optimum values of brake balance to be determined for both straight and curved braking. The effects of brake fade on brake balance are discussed. Different wheel antiskid systems are analyzed, and test results are presented for three domestic vehicles. A methodology for determining expected safety benefits of advanced brake systems is reviewed.
1974-02-01
Technical Paper
741095
J. V. Clore, F. Thorley
Microcomputer technology has added a new dimension to the design of test instrumentation, but the connotations of the name microcomputer have a tendency to build barriers rather than offer solutions to problems. Historically, computers have been treated as systems or identifiable subsystems in instrumentation applications. The implications of complex hardware and mystical programming is often sufficient to direct the user to alternate technologies. In a new light, clear of earlier prejudices, the microcomputer becomes a functional module like other LSI devices. Flexible and economical systems involving logical control, data gathering, and numerical calculations are possible utilizations of these relatively new devices. This paper discusses a facility to assist the designer in development of test instrumentation. Emphasis is placed on use of the microcomputer as an integral part of system design. Test instrument applications are cited.
1974-02-01
Technical Paper
741094
C. E. Bridge, M. E. Gatt, D. W. Howard
Factors which govern the selection and application of a computer based Real Time Data Acquisition System are identified. The impact of programming language level as it affects both hardware and personnel requirements are noted. Interface considerations with the laboratory test facility are presented.
1974-02-01
Technical Paper
741093
Don R. Sutherland
The General Motors Research Laboratories have equipped two engine test cells with instrument systems containing minicomputers. These systems measure 200 variables and convert them to engineering units for display to the test operator on a high-speed video terminal. The computers also perform calculations such as mass airflow, composite inlet temperature, and equivalent horsepower, which are combinations of several measured variables. Many of the test parameters are corrected to standard conditions of temperature, pressure, and humidity. This paper discusses these systems, mentioning both past experiences and future plans for linking into a host-satellite network.
1974-02-01
Technical Paper
741092
George Y. Kimm
A real-time process computer network has been developed at the General Motors Research Laboratories. Minicomputers are connected to a large computer in a satellite-host configuration. The minicomputers are dedicated to local experiment activities. The expensive peripherals and the high-level programming capabilities at the host are made available to the minicomputer users.
1974-02-01
Technical Paper
741129
Charles T. Darragh
A hydrodynamic retarder for heavy duty highway trucks has been developed to fill the need for a high capacity silent truck retarder that is independent of truck ground speed. This retarder is mounted between the engine crankshaft and the flywheel to take advantage of the transmission speed multiplication. Engine oil is the working fluid and the engine cooling system is used to dissipate the heat of retardation. The retarder designed for the new Caterpillar 3400 Series of heavy duty truck engines is described. Ratings that can be adjusted from 200 to 550 hp with minor hardware changes and unitized construction that can be adapted to many other engine configurations are the unique features of the design.
1974-02-01
Technical Paper
741128
Andrew Arabia
This report has been developed as a review of the general design and operation of European commercial vehicles from a product planning point of view. Particular regard has been given to the optimum utilization of petroleum fuels. Certain patterns established overseas may be of help in planning future truck designs in the United States to cope with the possibility of increasingly restricted fuel supplies.
1974-02-01
Technical Paper
741126
Ryoji Kihara, Taro Yamaguchi, Yasuo Mikami
This paper describes the recent trend toward dieselization of light and medium duty trucks in Japan. The customers needs are of prime consideration in engine development. Improvements have been made mainly in the areas of increased power, fuel economy, and anti-pollution. Maximum effort is being applied to meet government regulations both in exhaust emissions and noise. Some of the recent engineering developments in light duty, high speed diesel engines in Japan are described.
1974-02-01
Technical Paper
741127
Fumio Suzuki
The development of the Datsun pickup is traced from the post-World War II model with a wooden body, to the modified passenger car, to the current independent truck model. Some differences between the Datsun pickup and other Japanese-made trucks and American-made trucks are discussed. It is noted that the Japanese stress load efficiency: the Americans do not. Problems with size-dependent taxation rates; crowded roads; and scarce, expensive oil supplies have all led to a compact, economical design. Also discussed are the truck's adaptability to export destination requirements and its body construction.
1974-02-01
Technical Paper
741133
M. G. Bekker
A simple method based on bevameter soil values enables the engineer to evaluate the motion resistance of a pneumatic tire, in the given soil, and to perform parametric analyses of design and performance. The parameters measured include, besides soil parameters, the following characteristics of the tire: width, diameter, inflation pressure, carcass stiffness, and load. An inexpensive electronic desk calculator assures accuracy of prediction that is more than satisfactory.
1974-02-01
Technical Paper
741134
Robert M. Allen
This paper explains how structural properties of radial and bias ply truck tires affect tire and vehicle performance. The author concludes that a knowledgeable evaluation of the pros and cons of both bias and radial ply truck tires be based on individual operational evaluations and the compromise of tire characteristics which best satisfy needs. Neither radial nor bias ply truck tires can be generalized as the superior choice since each type has areas of superiority.
1974-02-01
Technical Paper
741131
R. Bertodo, T. W. E. Downes, I. D. Middlemiss
The emission control of small naturally aspirated diesels has posed severe problems and it has been generally thought that their acceptability in pollution sensitive areas would decline. The investigation described attempts to reverse this view. The exhaust quality of engines of this type can be improved by reducing the combustion temperatures and/or reducing the initial heat release rate: a range of methods of achieving this were examined and found commercially unacceptable. A qualitative review of the problem led to the evolution of a modified cycle characterized by high turbulence leading to higher air/fuel mixing rates and faster diffusion burning. This “Squish Lip” combustion system allowed CARB 1977 projected emission levels to be met on development engines without performance deterioration. Bench and field trials are in hand and a second generation system for truck applications is being evaluated.
1974-02-01
Technical Paper
741132
Ralph C. Raabe, Ioan Burche
Noise tests were conducted on new and retreaded truck tires of a wide variety of patterns using three different procedures. Single tires on the test wheel and 2-tire sets on the road were correlated with the standard 4-tire sets in accordance with the Recommended Practice SAE J57 Procedure. The correlation was analyzed and the conversion techniques were discussed with the conclusions that it is possible to convert test wheel data to equivalent road test data. The results show that retreaded truck tires are not noisier than new tires of similar construction and tread design.
1974-02-01
Technical Paper
741108
R. Douglas Roland, Roy S. Rice, Edward Kakaley
A recently completed research program has dealt with the problem of determining the influence of tire construction properties on vehicle braking and handling performance. Several tire properties that affect vehicle dynamic response have been identified and their effects quantitatively determined. Laboratory testing of a large sample of tires has shown that aspect ratio and basic construction type (that is, bias, bias-belted, radial) can significantly affect tire peak braking coefficient and cornering stiffness. The results of computer simulation studies and experimental tests with four automobiles have shown that the effect of changes in the peak braking force coefficient of tires on the average longitudinal deceleration of vehicles with fixed brake proportioning was small.
1974-02-01
Technical Paper
741106
Ir. A. Dijks
Most of the studies concerning wet skid resistance of tires concentrate on the effect of a single factor, the other variables being kept constant or assumed to be constant. In the Netherlands, the Vehicle Research Laboratory of the Delft University of Technology, in cooperation with a working party of the Institute for Road Safety Research (SWOV) has conducted extensive series of measurements according to statistical multifactor test programs. The wet skid resistance is rated by three coefficients: The peak value of the normalized braking force, the locked wheel value, and the maximum of the normalized side force. Special test programs are described which aim to investigate the influence of road surface parameters, such as texture depth and SRT values (British Pendulum Tester), and of tire parameters on wet skid resistance. The tire parameters consist of tread factors, compound factors, and a carcass stiffness parameter.
1974-02-01
Technical Paper
741109
F. Shaw
Reliability in a finished product can only be ensured when the designer has taken care to achieve the optimum solution to the sum of the needs of a particular set of circumstances. To follow this design philosophy, the designer must determine the function of the product, the length of time it will be required to operate correctly, and the amount of maintenance which is acceptable. When the necessary knowledge and information have been obtained from all available sources, then it is time to translate this concept into a product design. The engineering drawing is the message which communicates a reliable design to the production department so that it may be converted into a reliable product. The key to successful design is collaboration among as many designers as possible to maximize the amount of information and the number of ideas available, with one “manager of design” to coordinate their activities.
1974-02-01
Technical Paper
741107
Paul S. Fancher, James E. Bernard, Lloyd H. Emery
Results which have been obtained from flat-bed tire tests and linear-range steady-turning vehicle tests show that tire-in-use factors have a large influence on the normal driving performance of passenger cars. Test data for bias, belted-bias, and radial tires have been gathered to quantify the effect of inflation pressure, tread wear, and shoulder wear on tire shear force performance. A mobile tire tester has been used to measure maximum traction characteristics for worn and under-inflated tires on wet and dry pavements. The importance of the interaction of steering compliance with tire force and moment properties has been examined.

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