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In certain types of city bus service some automatic transmission fluids can fail in less than 10,000 miles. In order to provide satisfactory transmission performance for longer mileage, improved fluids are required. An investigation was undertaken to obtain improved fluids. Fifteen different fluid formulations were evaluated in 30 city buses operated in normal service for more than 2,000,000 miles. It was determined that fluids fail because of frictional deterioration and oxidation. Based on these evaluations, only two fluids were found to be satisfactory for more than 40,000 miles; one additional fluid was satisfactory for more than 30,000 miles. The remaining 12 fluids failed in less than 20,000 miles.

This paper presents an analysis of the economic feasibility of a demand-responsive transportation system employing driver-operated vehicles on existing street networks. The system is designed to meet the general public transportation needs of a suburban community. The analysis follows traditional economic theory in developing demand and supply curves for the transportation service as a consumer good, followed by an investigation of the equilibrium between demand and supply under various market conditions. Cost models specifically applicable to a transportation service with demand-responsive attributes are formulated to calculate the system supply functions, and an attitudinal survey is employed to generate estimates of demand in the case study community. The demand and supply equilibrium situations are investigated with respect to funding alternatives and sensitivity to changes in supply and demand variables.

The combustion system developed for the General Motors GT-309 regenerative gas turbine is used to illustrate pertinent structural, performance, and exhaust emission considerations when designing for a vehicular gas turbine application. The development of each major component and the performance of the combustion system as a whole are reviewed. The satisfactory performance and durability potential of the GT-309 engine combustion system have been demonstrated by extensive operation in a component test facility and in several test cell and vehicle installed engines. Exhaust emissions of unburned hydrocarbons and carbon monoxide are minimal and are of no concern from an air pollution standpoint. No objectionable exhaust smoking and odor are produced.

A laboratory test method has been devised to measure the variation in coefficient of friction values of a brake lining as it passes through the various degrees of wetness. The results of tests on two linings are shown: the first one of the most sensitive lining material tested to date; the second an improved material.

The assembly and particularly the reduction of the mass and stiffness matrix for a large system can be a significant portion of the computational cost of finding the mode shapes and natural frequencies. Therefore, parameter studies for design purposes can be prohibitive if these matrices are reassembled and reduced for each change. The purpose of this paper is to outline the procedure for using the modes of the original system to determine the dynamic characteristics of the changed system. The method also results in computational savings for boundary condition changes and for large systems that are nearly-symmetric except for a few mass and stiffness changes. To illustrate the method several changes are made to a ladder frame. The results from an analysis using the reconstructed mass and stiffness matrices and the modal synthesis technique are compared to show the accuracy and freedom requirements.

During development of the General Motors rotary engine, the lubricant was recognized as important to its success because certain lubricants produced deposits which tended to stick both side and apex seals. Consequently, it was decided to develop a rotary engine-dynamometer test, using a Mazda engine, which could be used for lubricant evaluation. In an investigation using an SE engine oil with which there was rotary engine experience, engine operating variables and engine modifications were studied until the greatest amount of deposits were obtained in 100 h of testing. The most significant engine modifications were: omission of inner side seals, plugging of half the rotor bearing holes, pinning of oil seals, grinding of end and intermediate housings, and using a separate oil reservoir for the metering pump. Using this 100 h test procedure, three engine oils and five automatic transmission fluids were evaluated.

A single-wheel trailer has been designed and built to study the origins of tire noise and its basic characteristics. The single test tire, nominally the 10.00/20 size usually mounted on large trucks and semitrailers, is located 12.2 m (40 ft) behind the rear axle of the towing vehicle to isolate it from other noise sources. Reflective surfaces that could interfere with noise measurements are minimized by the high, single-beam construction of the trailer. The towing vehicle is modified to reduce its noise and wake in the vicinity of the test tire, which can be loaded to 22.2 kN (5000 lb) by dead weights and rolled at expressway speeds. Because of its unusual configuration, the dynamic behavior of the trailer was studied prior to design to help determine several design parameters and show that the trailer would follow well. Extensive stress analyses of the trailer beam and other structural elements were also required.

The principal objectives of this study were first to obtain experimental curves of angulation versus moment of resistance of the human neck in hyperextension and lateral flexion, and second to determine angular limits short of significant injury observable in the unembalmed subjects employed in the study. The first of the tests were of the “static” type with load applied over a period of approximately 1s. To determine the applicability of the data to dynamic conditions, tests were also made of the dissected neck at angulation velocities comparable with those of typical accidental injury. Overall resisting moment and injury threshold were similar under the dynamic loading, but somewhat greater moment of resistance was noted during the (earlier) portion of the loading cycle when angular velocity was greatest.

Effective performance of functional automotive components requires fluid sealing under compatible conditions. One method of determining this compatibility is through the use of immersion testing under a variety of conditions that simulate those experienced in actual use. By measuring the changes in the physical properties of the seal materials after immersion a judgment can be made regarding seal/fluid compatibility which will be encountered later in actual use. A series of immersion tests using representative seal materials and automotive fluids; namely, gear oils, transmission fluids, and motor oils were conducted within the framework of the Technical Committee on Automotive Rubber, jointly sponsored by SAE-ASTM.

Studies were conducted using spark-ignited reciprocating engines to evaluate ammonia as an alternate fuel for certain military applications. Conventional engines were found to perform poorly on ammonia. Several practical methods for improving engine performance while burning ammonia are described which include increased spark energy, increased compression ratio, engine supercharging, and hydrogen addition to the fuel. Dissociation of ammonia was investigated as a practical means for supplying hydrogen to an engine. The study indicates that satisfactory engine performance can be obtained while burning ammonia. Auxiliary equipment and controls necessary for vehicular use will require development.

A facility for the aerodynamic testing of scale model vehicles has been developed. Suitable test section geometry, ground plane simulation, model setup technique, flow quality, and aerodynamic force and moment measurement capability are provided for automobile models of 1/4 to 3/8 scale. The maximum velocity of 160 mph enables 3/8 scale, 120 in wheelbase vehicles to be tested at Reynolds numbers approaching 5 × 106, based on wheelbase. A 3/8 scale model in a 160 mph airstream is dynamically similar to full-scale tests at 60 mph. Details of the facility are described.

A LOW-TEMPERATURE study of the relationship between the performance of a step-type automatic transmission and the transmission fluid viscosity is reported in this paper. It is shown that the low-temperature malfunction of these units is due to the viscometric properties of the fluid and that at the temperature at which the fluid reaches a certain critical viscosity the transmission will fail. A mathematical analysis of the mechanism of failure supports the conclusions drawn from the experimental study.*

One of the prime requisites for automobile radar systems is obstacle hazard evaluation, the extent needed being dependent upon the particular system application. Much of the information necessary for a radar system to assess the degree of hazard of a target must come from characteristics which can be measured by the radar itself. While the hazard evaluation capacity has not yet been developed for automobile radar systems, research to provide this capability is in progress. Continuous wave (CW) scattering measurements have been made in a manner which is consistent with automobile radar operation. Various aspects of simple targets and of an automobile were measured in a microwave anechoic chamber. Both horizontal and vertical linear polarizations were transmitted and their co-linear and cross polarizations received. These data have been used to confirm the existence of and to understand certain scattering mechanisms.

Most transducers offered commercially are suitable for laboratory, aerospace, or industrial process applications but do not meet additional, stringent automotive requirements. A need exists, both present and future, for various types of transducers in automotive powerplant control systems. Possible electronic systems and subsystems requiring transducers are discussed, and the types of transducers needed for these systems are described along with a discussion of a general set of specifications with respect to accuracy, reliability, and durability. Substantial transducer development is needed to enhance the advancement of certain automotive electronic systems. This paper points out these requirements to the electronics industry in an effort to encourage a mutual industry development that will advance the technology.

Tests of laser ignition are conducted in a combustion bomb. A range of fuels is investigated comprising isooctane, cyclohexane, n-heptane, n-hexane, clear indolene, and No. 1 diesel fuel. The ignition characteristics of laser-induced sparks are compared with sparks generated with a spark plug for different air/fuel ratios. The power density required to produce laser induced sparks is investigated. Although laser ignition appears to be impractical as an ignition device because of its low efficiency and high cost, it presents some interesting possibilities compared to the standard spark plug in that the laser spark is electrodeless and can be positioned anywhere inside the combustion chamber. Its primary use appears to be as a research tool.

The conflicts in the design of turbines for an automotive gas turbine engine are examined. Considerations of stress, efficiency, engine and vehicle acceleration requirements, and compatibility of the flow path are shown to impose a number of opposing requirements. The philosophies used to compromise the conflicts in two successive engine designs are presented. Following a discussion of turbine test facilities, test results are presented for a typical turbine.

Secondary air scheduling and average delivery rate have a great influence on the performance (carbon monoxide and hydrocarbon cleanup) of rich thermal manifold reactors. A continuously modulated secondary air system was devised to provide a tailpipe air-fuel ratio that did not change significantly with engine speed or load when a “flat” carburetion calibration was incorporated. This system involved throttling the inlet of the air pump(s) so that the air pump and engine intake pressures were equal. The continuous air modulation system was compared with an unmodulated system and a step-modulated system. The secondary air systems were investigated with both GMR “small volume” cast iron thermal reactors and Du Pont V thermal reactors on modified 350 CID V-8 engines in 1969 Chevrolet passenger vehicles. It was found that thermal reactor performance improved with each increase in control of the secondary air schedule.

This paper evaluates the tendency of lip seals to fracture in a test apparatus in which dynamic runout is 0.010 in and the temperature is cycled between -30 and 0 F. Seals made of eight different polyacrylate polymers were soap-sulfur cured with various types and amounts of carbon black. Physical tests included room-temperature flexibility defined by Young's modulus at small strains, standard tensile tests at room temperature, flexibility at sub-zero temperatures determined by a Gehman test, and sub-zero starting torques of the seals. Primary determinant of successful fracture resistance is a low starting torque resulting from good low-temperature flexibility. The effect of adding graphite to some of these formulations is described and some current commercially available seals are evaluated.

As the design of automobiles changed over the past seventy years, manufacturers have increased the usage of decorative trim to further enhance the beauty of styling concepts. As new trim materials were introduced and parts became more complicated in design, producers have continued their efforts to produce decorative trim parts which remain attractive during the service life of the automobile. The service performance of trim materials in several geographic locations, the use of accelerated tests to predict service performance, recent developments in improving the durability of plated parts, and requirements for producing quality exterior decorative trim are reviewed in this paper.