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MR. KELLEY discusses the application of the automatic transmission to passenger cars, buses, cross-country military vehicles, off-the-highway equipment, and trucks, placing particular emphasis on the development of satisfactory units for the truck field. Today, he says, there is a strongly crystallized trend among engineers toward the use of only two engineering principles for handling the variable drive ratios in automatic transmissions. These are the Hydra-matic and the hydrodynamic principles.

IN this paper the author explains a new method for the determination of the fatigue life of bevel and hypoid gears. This method is said to offer a means for comparing various tooth forms and gear mountings. Briefly, it consists of making a layout in the mean normal section of the tooth, and of calculating the tensile stress in the fillet when the maximum load is applied at its highest position on the tooth. Consideration is given to the fact that in cases where the contact ratio is sufficient to ensure at least two teeth in contact at all times the load will be divided between the teeth. Such factors as impact, inertia, and temperature are given consideration. A graph is plotted using this calculated stress and the number of cycles to failure resulting from extensive bending fatigue tests on both bevel and hypoid gears. With the aid of this graph the fatigue life of new gear designs may be estimated.

THIS paper presents a discussion of tests and mathematical studies made during the past year in connection with the synchronization of brakes on truck-trailer combination units. These developments point to a clarification of the many misconceptions and exaggerated ideas which have been built up concerning timing, steering, and braking necessary to offset the dangerous jackknife type of skid, as well as the slide which frequently occurs on slippery pavements. The writer describes two types of jack-knife which may occur if the braking power on certain axles builds up more rapidly than on others. A third type of jackknife may result from steering as, for example, in a sudden turn to avoid an obstacle, even with no brakes applied. The writer points out that synchronized braking cannot offer anything spectacular in the way of shortening stopping distance unless build-up time is shortened considerably in the process.

IF the maximum is to be achieved from our design efforts, says the author, we are finding that we must specifically design the machine around the human operator and his physical and mental capacities. Mr. Simons shows here what is being done to incorporate this philosophy into the design of tractor seats. His approach to the problem is: 1. To record the absolute tractor motion in all three dimensions simultaneously while the field operation is in progress. 2. To analyze these records in the light of human tolerances. 3. To design the seat suspension to isolate against the objectionable part of this motion.

A unique research test program of vehicle electromagnetic radiation that might cause radio interference has provided data in areas not previously studied. Reports are presented on: electromagnetic radiation from single vehicles versus multiple vehicle radiation (20-1000 MHz), horizontal versus vertical polarity of radiation from vehicles (20-1000 MHz), and microwave (1-2.5 GHz) radiation from vehicles. Included is a brief history of the automobile industry and SAE investigations of vehicle radio interference which have been undertaken since 1935.

The excellent performance of the modern automobile environmental control system tends to accentuate the passenger discomfort experienced during the engine warm-up period in very cold weather. Quick-heat systems utilizing combustion techniques can significantly reduce this warm-up period and can not only improve comfort, but also contribute to safety and improved engine life. These factors are discussed, together with details of a quick-heat system which reduced the warm-up time of a large American automobile by over 80% in actual tests.

The performance of eight refrigerants in an automotive air conditioning system has been analyzed. In addition, the problems of hose permeation and elastomer compatibility have been studied. The results indicated that two of these new refrigerants have promise in auotmotive air conditioning.

The dependence of the compressive stress-strain behavior of plastic foams on the loading geometry and its significance in relation to the cushioning design study for automobile safety is explored. Experimental load-deflection responses obtained under dynamic (impact) and static conditions using loading objects of various different geometry are analyzed. A strong interaction between the loading geometry and the material response existed. It was found that the stress-strain behavior of plastic foams varied, whether under static or dynamic conditions, with the loading geometry. The linear load-deflection response observed in the case of hemi-spherical loading differed from that of the convoluted faceform loading, while the response for the flat plate compression deviated from both.

To supplement the subjective appraisal of seat comfort, a new instrument capable of quantitative measurement and real-time display of a seat load has been developed. The pressure detecting part comprises 300 small pressure transducers of disc type installed inside an automobile bucket seat. Highly sensitive semiconductor strain gages are used as pressure sensing elements. The outputs from sensors are displayed on a CRT device whose screen is crosshatched into 300 parts corresponding to each sensor. Pressure distribution on a seat is shown by the difference in brightness on the screen. Brightness modulation can be made in five stages or on continuous level. The outputs are recorded and reproduced by a data recorder. Equipressure contours can be plotted through a digital computer. Some of the vehicle test results are described.

The basic raw material used in manufacture of fiberboard is cellulose fiber which is obtained from trees and/or reclaimed (waste) paper. Cellulose fibers are obtained from trees by the “pulping” operation which involves debarking, chipping, and cooking with chemicals to separate the cellulose from other wood components. Cellulose fibers are obtained from reclaimed paper by mechanical repulping in water. Cellulose fibers, once pulped, go through the stock preparation phase where they are cleaned and sent through a refining stage. The conditioned fibers are sent to the paper machine in a water slurry for conversion to paperboard. The paper machine is a large controlled water removal system having four distinctive manufacturing steps: mat formation, pressing, drying, and calendering. The paperboard from the paper machine is sheeted or wound in rolls. It may be sold in this condition or undergo further processing such as laminating or coating before it is sent to the automotive fabricator.

From efforts to utilize waste wood fiber more fully from the lumber industry has come a substrate now widely used for interior trim parts in automobiles. Hardboard results from the separation of wood fibers, formation of the fiber into a mat, and subsequent consolidation with heated presses. Humidification of the pressed board followed by trimming and edging complete the manufacturing process of hardboard. Environmental improvement is a continuous program in the hardboard industry and has resulted in the development of a number of salable byproducts from mill residue.

The paper describes many of the methods of fabricating and finishing fiberboard parts for the automotive industry. Fabricating methods include die-cutting, crease bending, forming, fastening, and adhesive bonding. Finishing methods discussed are paint roll coating, spray painting, printing, and embossing. The equipment and tooling required are also described.

A Procedure for Optimizing Elastomeric Mountings (POEM) is described which provides a systematic investigation of vehicle ride performance as a function of both the spring rate and damping of a selected mounting. POEM assumes the mounting design and its placement on the vehicle have been established. Then nine mounts satisfying a three-level factorial experiment in spring rate and damping are evaluated. Evaluations can be subjective or objective and can employ laboratory simulators or road tests. Dynamic properties of the mounts are measured at simulated on-car conditions. Computer, step-wise regressions of the data are performed to define any performance/property relationships. Final regression equations are contourized by computer, displaying performance versus dynamic properties. Results enable easy and quantitative optimization of dynamic properties. Examples of POEM analyses are given.

This paper presents a brief description of each of the main types of fiberboard used in the automobile. It covers typical applications for fiberboards with detailed information only on the interior trim parts. Applications where fiberboard and plastics compete are discussed. Also included are the advantages and disadvantages of fiberboards. The effect of humidity changes on fiberboard resulting in dimensional changes and warping tendencies in the fiberboard are explained with illustrations which emphasis the need for proper fastening of fiberboard and a method of measuring war-page. Test methods, performance testing, and possible future applications are discussed.

This paper describes a constant natural frequency spherical elastomeric spring element. The concept of constant natural frequency and its advantage in providing consistent ride quality with varying vehicle weight is reviewed. Performance data on the spherical spring for both laboratory and field tests is presented and evaluated.

This paper discusses the sources of noise pollution in the civilized human environment and reviews the numerous criteria which have evolved for their assessment and description. It is stressed that criteria should be established in simple basic units and dBA values are recommended. By far the most common single source of annoyance is that of road transportation noise and this aspect has been covered in specific detail. Methods of predicting vehicle noise from the engine design and operating parameters are shown and some measures for noise reduction are discussed.

This paper describes the development of a process that will mold a urethane resin in the form of a laminate. The urethane resin is a most unusual material: it can be formulated to produce thermosetting foam of almost any density, and the formulation can also be made to produce either a flexible or rigid foam. It has excellent adhesive properties, which we have used to make the laminate. The process produces a laminate of two skins, which are combined with a film of urethane resin in its liquid form. This combination, when placed in a heated mold, causes the resin to expand until both skins reach the confine of the mold. This then cures to the shape of the mold and the texture of its surface, making it possible to mold sculptured and formed shapes or panels, which can be used for interior trim for automobiles.

An automotive tune-up clinic for the purpose of reducing undesirable exhaust emissions was held March 14, 1970, as part of an environmental teach-in. The event was sponsored by the student branch of SAE at the University of Michigan. The results of this event clearly show that improper automotive maintenance can be a major factor in atmospheric pollution. It was found that idle hydrocarbon emissions were reduced by an average of 55% with a tune-up in which the idle mixture ratio and speed were adjusted for minimum carbon monoxide emissions. Our conclusion is that the individual motorist must begin to develop an attitude of responsibility toward the maintenance of his automobile to ensure low emissions.

Maintenance programs indicate that exhaust emission controlled cars with hydrocarbon (HC) emissions above 400 ppm or carbon monoxide (CO) above 2.25% will have emissions reduced by proper maintenance. Distribution curves of recent surveillance data show that one-third of the 1966-1969 cars have emissions above these assured reduction levels. Calculations show that maintenance based on reducing high emitters of HC and CO should reduce total HC by 19%, CO by 30%, but increase oxides of nitrogen (NOx) by 9%. Further calculations show that maintenance based on reducing high emitters of HC, CO, and NOx should reduce total HC by 20%, CO by 25%, and NOx by 6%. The inclusion of NOx testing along with HC and CO in the idle inspection test method is nearly as effective in identifying high emitters of HC, CO, and NOx as the longer seven-mode test method.

Lap-shoulder belts, although infrequently used by vehicle occupants, are demonstrating a remarkably high reduction of injury in collisions where they were used. A search was made for all collisions in the GM files where at least one occupant was wearing the lap-shoulder belt combination restraint. Of the 160 cases found for this study, 60% of the vehicles had heavy damage of the type often associated with occupant injury: however, 99% of the lap-shoulder belt users either had no-injury or only minor injury. The only two fatalities found in the study involved accidents occurring under unusual circumstances. This paper describes 18 of the most severe damage and/or injury cases by means of photographs and collision descriptions. Some grouping of body injuries is also listed. These data illustrate that the use of different occupant restraint configurations (unrestrained, lap belt, and lap-shoulder belt) affect the severity of injuries to various body areas.