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The hygroscopic tendencies of several types of motor vehicle brake fluids are compared in both bench tests and in simulated service equipment. The effect of moisture on the boiling point and vapor pressure of some new types of brake fluid are discussed with respect to the specific safety aspects of each fluid. Vapor lock temperature data for conventional and less hygroscopic brake fluids are developed which help to translate laboratory data into information of use to automotive engineers.

The new brake fluid, called LMA (low moisture avidity) fluid, which complies with the SAE 70R3 specification, has the distinct advantage of absorbing less moisture than conventional glycolether brake fluids. No malfunctioning of components has been experienced in brakes or clutches over a test period of 2-1/2 years. Brake trials also show that the tendency to vapor lock under severe braking has been reduced with LMA fluid. Furthermore, the low temperature viscosity of LMA fluid is hardly affected by increase in water content, whereas with conventional fluids this viscosity can be more than doubled.

At present in the United States, passenger car manual transmissions are almost exclusively of the strut type blocking synchronizer. General design parameters for this type of synchronizer, including formulas, present design practices, methods of evaluation, and variables that most affect synchronizer performance, are presented.

The problem of wheel/tire induced vehicle vibration is now of such proportions as to be of interest to both vehicle builders and users. This paper includes a description of the factors involved in generating the vibrations and a discussion of several approaches and/or solutions to the problem.

Concept and engineering feasibility of a new child restraint system has been demonstrated by various dynamic tests. These tests indicate that the restraint system will retain a child-like dummy in rollovers, side impacts at 17 mph, and in frontal impacts as severe as a 30 mph barrier crash. This unique system that can be used in any passenger seat position having a lap belt consists of a partially encapsulating shield and an internal box-like 3-inch high seat.

One cause of vehicle disturbance is smooth road shake. Manufacturers are attempting to reduce vehicle sensitivity to shake input forces from tire-wheel assemblies by changing suspensions and body-frame structure, stiffness, by tuning engines on rubber mounts, relocating body mounts, and so forth. The similarity of tire nonuniformity and wheel radial runout, and the laboratory and production techniques for matching tire and wheel are described. The conclusions reached are that matching tires to wheels would be an effective stop-gap measure; that the ultimate goal is improvement in tire uniformity and wheel runout to the point where matching would be unnecessary; that tire lateral force variation and lateral wheel runout are not related to smooth road shake.

Wheel runout can be reduced by better wheel design, coupled with improved manufacturing processes. For example, it appears that runout is less if the spokes are eliminated, providing a continuous flange, thus permitting a reduction in press fit. The resulting disc is easier to form, tooling and maintenance of dies have been simplified, and when the disc is assembled to the rim, it should be more uniform, with less concentrated distortion. A new machine, to be used on a semiproduction basis, is proposed for measuring wheel runout more accurately.

The miniaturization and reliability associated with microelectronic circuits has allowed the alternator voltage regulator to be made an integral part of the alternator. This concept overcomes past limitations inherent in electromechanical and discrete component transistor regulators. Advantages gained from the concept include wiring simplification, reduced system complexity, greater reliability and longer life.

Recent development work has led to production of two new families of integral charging systems featuring semiconductor voltage regulators designed to employ integrated circuit electronic techniques. The severe application conditions defined by the environment under the hood of heavy-duty vehicles and passenger cars and the tight electrical performance specifications have been satisfied by integrated circuit techniques not previously used in an automotive application. Successful voltage regulator designs open the way for other vehicular applications of integrated circuits.

The modern, small, high-speed, 4-stroke diesel engine above all owes its development of today’s speeds of 4500 rpm to the objective of making it applicable to the passenger car. In 1936 Daimler-Benz was one of the first companies to bring out a passenger car equipped with a diesel engine. Its 4-cyl, 4-stroke engine with a displacement of 2.6 liter delivered 45 bhp at a speed of 3500 rpm, which was considered remarkably high at that time. This first diesel-engine-powered passenger car was so well accepted that after World War II a special development program was started, which in the last few years has led to production diesel engines with a top speed of 4500 rpm.

Strain analysis of stampings is explained. The system is based on the strain distributions obtained from 0.2 in. inter-locking circle grid patterns etched on blanks. The strain distributions are related to a developed formability limit curve and the mechanical properties of the gridded blank. The evaluation of the graphic relation of the strains to the formability limit enables the press shop to determine what factors should be changed to produce stampings with less scrap and lower cost.

Warp knit fabrics are accepted as automotive trim materials for seats and side panels. This preference is based upon consumer comfort and automotive manufacturer’s application and design advantages. These advantages are related to basic properties of warp knit fabrics. Solutions to current textile-automotive cooperative research programs will result in greater use of warp knits in automobiles.

The circular grid system, in which a pattern of 0.05-0.25 in. diameter circles electrochemically marked on sheet specimens is used, permits a visual display of the magnitude and direction of the strain from point-to-point of a stamping. Strain values obtained from the grid are plotted relative to an empirical failure curve to indicate proximity of a stamping to failure. Analysis of the strain distribution allows one to reduce the die tryout period, assist in establishing material specifications, evaluate die modifications, and monitor die variables throughout production runs.

A method to determine analytically the response of the human being to vibration is developed. This method uses a parameter called absorbed power. The advantage of absorbed power as a measurement criterion is that it has physical significance. It places vibration severity on an absolute scale and is applicable in the time or frequency domain.

This paper discusses the problems facing military vehicles operating in the riverine environment. Attention is given to studies conducted of water speed, drag and propulsion, vehicle egress, and methods for determining the nature of the environment. Also examined are the influences of the riverine environments on the vehicles designed to operate in them.

This paper reviews experiments for determining human response to vibration and interprets them in the vehicle vibration context. It reviews the author's research and compares it with findings of other investigators. From the results of vehicle tests, it is concluded that properly weighted “acceleration variance” is a meaningful measure of vehicle vibration. For a single vehicle subjected only to surface profile changes, a single number summed over all frequencies can be used. For two or more vehicles with different vibrational characteristics, acceleration variance must be computed in several frequency bands to yield correction factors that define the nature of the vibration.

An analytical technique has been developed which uses operational and physical environmental factors as design criteria for earthmoving equipment. A computer program that employs these factors is used in the design optimization of an integrated family of military construction equipment. Total environmental factors considered include: soils, vegetation, climate, transport, deployment, operation, service, supply, etc. Analytical design studies already conducted have produced a hypothetical equipment system that performs its mission at substantially less cost than existing military equipment systems.

The response of low carbon steel sheets to biaxial tension forces was studied in stretch cup tests of 3 and 8 in. diameter. Three levels of lubrication were obtained by the use of mineral oil, drawing compound, and hydraulic bulge pressure. The mineral oil and drawing compound were applied to hemispherical steel punches and a 0.004 in. thick polythene sheet was placed between these and the metal under test. Hydraulic bulge tests were relatively insensitive to plastic anisotropy changes in sheet metal. It was found that improving the lubrication in mechanical punch tests or lowering the plastic strain ratio r̄ had similar effects in increasing the height of the cup at fracture, transferring the maximum strains closer to the pole, and increasing the amount of strain which could be developed before fracture. Material with high strain hardening capacity distributed the strains more uniformly and therefore had better biaxial stretchability.

U.S. involvement in the limited warfare of Southeast Asia has imposed a new set of environmental problems on automotive engineers engaged in the design and development of military equipment. This paper is addressed, in general, to the identification and solution of the mobility related problems encountered in limited warfare and, in particular, to describing LTV’s approach to providing a response to the specialized and immediate needs of the armed forces in Southeast Asia. Essentially, LTV’s approach involves an initial analysis of the environmental conditions being encountered, and logically identifies the vehicular design parameters necessary to cope with these factors within the framework of the tactical situations encountered in limited warfare.

This paper examines specific design characteristics of the new 5 ton tactical truck M656. This vehicle will serve a multitude of purposes such as cargo truck, personnel carrier, and prime mover for missiles and artillery. The M656 was developed with an eye toward specific requirements which had to be met in the areas of reliability, durability, mobility, and ease of maintenance. Human factors incorporated in the design provide for ease of operator control, maximum driver safety, and comfort. Reviewed in detail are factors considered in development of the powerplant assembly, cab design, drive train, suspension systems, and steering assembly. By designing the M656 from the start to military specifications, a new generation of tactical trucks was developed. By this direct approach the military was able to acquire a vehicle that had swimming capability, air transport feasibility, severe off-road operating ability, and extended maintenance intervals.