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Many of the modern, heavy-duty farm, construction, and industrial machines are being outfitted with some type of wet clutch. Either mechanically or hydraulically actuated, these oil-cooled multidisc clutches have much to offer when installed in the new higher horsepower equipment. The operation of wet clutches is outlined, and conditions of practical application are detailed.

Two balancer developments are followed through the conception and development stages into production. One design utilizes gear driven auxiliary flyweights, and the other, an oscillating counterbalance driven by crankshaft eccentrics. Vibration reductions up to 85% have been realized.

Application of the hydrostatic transmission to a farm and light industrial tractor involved many special design and manufacturing considerations. A brief description of the transmission is given, and some of the special considerations along with their solutions are discussed. Emphasis is placed on the importance of having the proper control system to provide desirable performance and endurance characteristic for the tractor. Because the controls of a hydrostatic by necessity are quite different than for a conventional tractor, particular emphasis is placed on the control portion of the overall development program.

After a short discussion of methods for measuring friction losses in diesel engines and the conclusion that it is not yet possible to determine accurately the true friction under firing conditions, motoring loss measurements for a number of automotive diesel engines of all sizes are presented. A simple formula that correlates this information is proposed. The breakdown of the observed friction into its components is examined in detail, permitting better understanding of the makeup of the total friction and of design changes necessary to reduce losses. A simple piston friction rig used to examine design parameters is described.

A review of benefits to be gained by automatically controlling the slip properties of truck tires indicates that up to 40% shorter stops and complete jackknife control when braking is possible. A simple all-mechanical device is described for use with air brakes which, from the data, shows 7-30% shorter stops, no tire degradation, and full steering control. Data is presented from full sized semi-trailer truck skid tests.

This paper attempts to illustrate some of the reflection characteristics of exhaust systems, suitable for piston ported, crankcase compression, naturally aspirated two-cycle engines. In particular, the application is even narrower, being concerned principally with those engines of the spark ignition, gasoline burning type where a high bmep is desirable. The two principal exhaust systems considered are the diffuser and the expansion chamber. Both are analyzed experimentally and theoretically and presented as measured and digitally computed pressure-time diagrams in simulated and actual engine exhaust systems. These are compared and discussed.

An emergency brake system for combination vehicles is described. It provides the driver with control similar to service brake control of all of the emergency brakes on combination vehicles, whether it is panic or controlled application. Operation of the modulated emergency valve is explained, as are valve characteristics, system timing, and installation.

Preventive maintenance is just as important in 1-cyl air cooled engines used in golf carts as it is in an automobile. The paper describes the characteristics of 2- and 4-stroke engines and then outlines the features of a maintenance program for them. Included are care of air and carburetor cleaner, use at proper speeds, use of fresh gasoline, spark plug and carburetor problems, and overall general care.

It is one thing for an engineer to design the safest vehicle and equip it with the most effective restraint system. It is quite another to have the user of this fine equipment use it to lengthen his own life. This paper explains the process one segment of a large government agency has successfully used to get approximately 88% use of the restraint system on the job and a slightly lower percentage of use by employee's families in the family car. Program emphasis has been on the 3-point lap/shoulder belt for maximum head protection.

The VTA-1710 series engine described represents Cummins' entry in the 800 hp class engine. This paper presents a general description of all design modifications that were made to achieve a 15% increase in power in the same package size with a conservatively loaded basic structure. Design changes to the engine are carried throughout the engine horsepower range of existing rating of 500, 635, and 700 hp to achieve a standardized family concept with a high degree of interchangeability.

This report is oriented to: 1. Research and development in highway transportation under sponsorship of the Bureau of Public Roads. 2. Traffic operations and control aspects of highway transportation. 3. Importance of combining vehicle engineering and human engineering along with highway engineering in programs to improve the service, effectiveness, and safety of highway traffic operations. As these new traffic systems, or improvements in the performance of highway transportation emerge, they will require new and far reaching decisions not only for highway users and administrators but for industry as well. Along with decisions there must also be commitments and investments of a scope and magnitude not experienced before. This report describes how new traffic systems are developing, what they consist of, and how they will be of benefit. It treats major features of new traffic systems which very directly involve vehicle and human engineering.

This paper outlines the conception and development of rating brakes. It is related to the adoption of the snub method of rating brakes as described in SAE Recommended Practice J880 and proposes an alternate continuous drag test method utilizing a dynamometer adapted to a road vehicle.

Modern data acquisition methods combined with new testing and analysis techniques are revolutionizing product design and development. Detailed analysis of recorded vehicle drive-line data has given today's engineer new insights into drive-line dynamics. This paper discusses how vehicles can be analyzed as a series of torsional springs and inertia masses. A two axle, 300 hp, 15 cu yd earthmoving tractor scraper (model 621) is used to illustrate significant factors. Main emphasis is on drive-line resonant torsional vibrations and shock loading. Diesel engines as torsional vibration exciters and transmission clutches as the major shock load producers are covered in some detail. How analog computers can effectively be used to facilitate vehicle development is briefly discussed.

A method is presented for computing the energy dissipation rate in a wet clutch that is part of a vehicle transmission system. This method takes into account the transients in the vehicle prime mover, the hydraulic torque converter, the powershift transmission, and the vehicle load. The clutch energy rate is then used as an input to attempt to predict the interface temperature at the clutch surface. The solution of the Fourier-Poisson unsteady state heat conduction equation is carried out using a finite difference method. The calculation of this interface temperature, called temperature index, is then correlated to actual clutch failure through experimental laboratory clutch testing. Results show a temperature index level above which failure is likely to occur regardless of the variation of clutch parameters.

Primarily a review of hardware details that allow quick changes and high utilization of dynamometers and kindred equipment. Discussed are tachometry, torque measurement quick disconnects (electrical and shaft), desirable control system characteristics, and chassis dynamometers.

Farm tractor cab design with respect to quiet comfort and convenience is discussed. The areas of visibility, accessibility, environmental control, and noise suppression are investigated. Various approaches to accomplish optimum conditions in these areas are analyzed, components are evaluated, and design recommendations are made.

The engineer is often faced with the problem of forecasting the effects on human beings of the sound produced by equipment operating within the environment in which they live or work. A detailed measurement of sound pressure levels throughout the frequency spectrum is necessary for a complete analysis, but the standard sound level meter is probably adequate for most purposes and nearly as accurate as more complex computations. This paper provides useful criteria for specifying performance of equipment or for limiting the exposure of human beings to noise in certain acoustical environments.

For the cab isolated operator to monitor properly the operation of his machine requires a new complexity of early warning signals, failure warning signals, and process monitoring signals. This paper discusses the operator’s requirements and the signal sending and readout hardware available and/or required to meet those requirements.

Has the wheel taken us to the end of our road? Biomechanics’ functional morphologic approach to problems reveals the feasibility of machine designs through studying living phenomena. In addition to the solution of standing problems, the method leads to a series of advanced concepts -- from a one-man cupola simulating an arthropod claw to a weapons firing platform based on the structure, form, and movement found in a snake -- which are useful for new weapons development in the light of our rapidly advancing technology. Outgrowths are expected from this type of investigation through design ingenuity.

Formaldehyde is an intermediate in the synthesis of edible carbohydrates from CO2, O2, and H2 derived from crew member metabolic wastes on spacecraft missions. Methods of accomplishing the synthesis of formaldehyde were studied, and the CO2 → CH4 → CH2O route was selected as the most suitable for spacecraft conditions. Partial oxidation of methane using heterogeneous solid catalysts, ozonated oxygen, and gaseous nitric oxide was investigated. The highest yield achieved was with nitric oxide, amounting to 2.5% of the methane admitted to a single pass reactor. The feasibility of converting CO2 into formaldehyde was demonstrated with a recycle system entailing two reactors. A methanation reactor converted feed and by-product CO2 into CH4; the CH4 in turn was oxidized to formaldehyde in an oxidation reactor. With recycling, essentially 100% conversion of CO2 to formaldehyde was achieved at ambient pressures.