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The conversion from submerged arc welding to electron beam welding (EBW) of transmission components at Clark Equipment Co. is described. The latter system permits the consistent holding of close tolerances and the obtaining of controllable and repeatable metallurgical structures. In addition, control of the weld and distortions is increased, and weld joints are made feasible in otherwise inaccessible locations. A brief history is presented which touches on the selection of transmission products for EBW, choice of EBW equipment, preliminary evaluation, and acceptance of the process by personnel. Then, the application of EBW to production parts is discussed.

The use of the Oklahoma State University Pump Contaminant Sensitivity Test, OSU-F2 Multi-pass Filter Performance Test, and knowledge of hydraulic fluid contamination levels in field tests have proved to be highly effective tools in the development of a reliable hydraulic system for a modern farm tractor. Goals for an improved filter system were: To provide as much filter capacity as economically possible; to increase the filter flow rate; to isolate the pumps from the sources of contaminants. These modifications corrected the problems: Brake friction surfaces which generated less contaminant; a pump with greater contaminant tolerance; an improved filtration system.

In any hydraulic system, we can, without reservation, say that the cleaner the fluid the better. But, since absolute cleanliness is usually unobtainable, it becomes important that we can readily measure and define the degree of cleanliness in a practical way. Two parameters seem important: number of particles and particle size. In examining hydraulic components as to type and usage, two areas of particle size are of special significance, 5 and 15 micrometres (μm). By counting all particles in a fluid sample above 5 μm and also counting all particles above 15 μm, two indexes are given from which a contaminant code* is derived. The thesis of this paper is that this code is useful in predicting the performance of specific components with the fluid.

Methods of assessing the ride comfort afforded to tractor drivers by their vehicles and the ride improvement provided by seat suspension are reviewed in relation to information available on the human tolerance to whole-body vibration. Experience with different methods of measurement is reported and a proposal made for the establishment of an internationally agreed method of ride comfort rating based on standardized undulating surfaces over which vibration of the driver's seat is analyzed, using frequency weighting to represent the differing sensitivity of the body to different vibration frequencies.

A farm tractor protection cab made of thin steel sheet pressings is described. The cab is designed and produced using entirely automotive-type procedures. Curved glasses and a dampening suspension of the glasses are found to be an important means of achieving a low noise level in the cab. Using the pressing technique when producing a steel cab makes it possible to give the various cab details rigidity with a minimum of material. When welded together, these details form a very stiff cab body, which gives the necessary mechanical strength. The curved surfaces, the radii, and the round forms, which from a tooling point of view are natural for pressed steel parts, also have a vibration-dampening effect on the entire cab construction, thus making it easier to design a quiet tractor cab. Mounted on a farm tractor of conventional design, the cab meets the noise rating number ISO N85.

This paper discusses some trends and influencing factors in passenger car fuel economy. Fuel economy and fuel consumption were calculated by a carbon balance method from HC, CO, and CO2 emissions measured by the 1972 Federal Test Procedure. The information presented was derived from nearly 4000 tests of passenger cars ranging from 1957 production models to 1975 prototypes. Data are presented for various model year and vehicle weight categories. Trends in fuel economy are discussed on an overall sales-weighted basis and for each individual weight class. Some of the factors that influence fuel economy are quantified through the use of a regression analysis. Particular emphasis is placed on the differences in fuel economy between those vehicles that were subject to federal emission regulations and those vehicles that were not. Three ways to characterize vehicle specific fuel consumption are presented and discussed.

This paper outlines the structure and interrelationships of the numerous European standards making organizations, with particular reference to agricultural machinery. Because many of the standards being developed by these organizations are becoming part of legislation in the various Common Market countries, their work is of great interest to the machinery manufacturers. Covered are the highway code-constructional requirements, safety constructional requirements, test codes, and engineering standards. The current status of requirements for lighting, tractor cabs (including structural tests, noise, and emissions), maximum speed limits, brakes, hitches, and safety in the various contries are discussed.

The recent history of automotive fuel economy in the United States is reviewed. As of the 1973 model year, the individual typical car on Ford's city-suburban route has experienced a 22% decline in fuel economy compared with that of 1967. In the aggregate, however, the decline has not been as great because an increasing proportion of small cars has entered the vehicle population. The factors which have contributed to the fuel economy decline of the typical car are average weight and engine displacement increases and measures taken to reduce exhaust emissions. As of the 1973 model year, emission controls have accounted for 60% of the total 22% decline based on Ford's city-suburban route.

The increasing use of hydrostatic drives in industry has motivated development of fluidic control devices, using hydraulic oil, for application to hydrostatic transmission pump displacement control. A closed-loop positioning servo using proportional hydrofluidic amplifiers and flowing hydraulic fluid to replace the numerous mechanical parts common to conventional servos has been developed. This hydrofluidic servo has been built in both a packaged servoactuator form and a modular form for integration with existing hydrostatic transmission pumps. Operating principles and performance of experimental units are discussed. Operation was evaluated over a 160-500 psig (11-34.5 bar) supply pressure range using fluid viscosities ranging from 220-5 cSt. It was concluded that hydrofluidic servos are practical and that their application in industry will be contingent upon the availability of off-the-shelf components.

Compared with conventional power trains, available axial piston hydraulic pumps and motors provide the designer of work vehicles in the 15-80 hp sizes an opportunity to improve the productivity, reliability, and serviceability of his machine. This paper provides the designer with information frequently overlooked in the initial application of these units.

The braking characteristics of three typical recreational snowmobiles have been studied. Of particular interest was the sensitivity of the machines to different applied braking loads. The data were collected using a variable-load braking apparatus and stop-action high-speed photography. The results have been described with an empirical equation. It was determined further that the most effective braking was achieved when the track was locked and this particular behavior has also been characterized by an empirical expression.

Laboratory development of modern diesel engine lubricants should ideally be done at the high output/speed conditions where the latest engines operate. In the late 1960's, the only engines available to the oil industry were the Caterpillar 1Y73 and the Petter AV-1. While useful test tools, neither of these engines can successfully operate at the desired conditions. Nor can they be successfully modified for that purpose. For these reasons, a joint project was established in 1969 between Chevron Research and List-Rosen-Wittek/AVL. Its purpose was to adapt one of the AVL diesel development engines to lubricant, emission, and fuel research. The design criteria developed included modern speed/output capability, durability, low maintenance, special lubrication features, adaptability, and balancing. These requirements resulted in a completely new design. A prototype was constructed, and this engine ran in October 1972. The design features are described and illustrated.

A look at a chassis dynamometer installation, including the peripheral equipment necessary for vehicle cooling system evaluation, is presented. Also covered are the procedures, specifications and instrumentation used in conducting such a test.

The impact of farm and industrial tractors on the total national emissions picture is difficult to assess because the great diversity of uses for these machines results in a wide variation in duty cycles and degrees of utilization. Also, there is a general lack of detailed information on population and population distribution. This paper compares possible farm tractor duty cycle models and concludes that the widely used 13-mode federal heavy-duty diesel engine emissions test cycle can be used to estimate wheel tractor emissions. Estimates then are given for the amount of pollution released by wheeled farm and industrial tractors in 1972, based on the 13-mode cycle and population estimates derived from U.S. Dept. of Commerce, U.S. Dept. of Agriculture, and Farm and Industrial Equipment Institute data. Calculations show wheeled tractor emissions contribute 3.2% or less of the national total, depending upon the pollutant species.

Mechanisms that influence emissions of polynuclear aromatic hydrocarbons (PNA) from engines have been investigated with an on-line fluorescence PNA detector. PNA can accumulate at the surfaces and within the deposits of a combustion chamber, and some of these PNA are vaporized during engine operation. Increased heat input to established combustion chamber deposits (for example, from increased spark advance, knock, or high-speed operation) enhances PNA emissions, at least temporarily. At several steady speeds, PNA emissions were compared, using a rotary engine vehicle and a similar car with a reciprocating spark ignition engine. With the emission control system disabled, the rotary engine automobile exhibits very high PNA emissions relative to the piston engine. However, exhaust emission control devices, such as the thermal reactor on the rotary engine car, can be highly effective in destroying PNA.

Evidence is presented to determine the relationship between fuel composition and polynuclear aromatic hydrocarbons (PNA) formation. Emission rates of PNA were determined for gasoline engines in simulated city driving; in order to confirm the results, experiments were carried out with a vertical flow reactor. The PNA emission was found to depend on the different aromatic hydrocarbons present in the fuel. The addition of tetraethyl lead (TEL) to gasoline had little effect on PNA emission. The carcinogenic hydrocarbons like 1.2 benzanthracene and benz(a)pyrene, particularly associated with the more carbonaceous part of the soot, are preferentially deposited on the combustion chamber walls, as pointed out from vertical reactor experiments.

The Eaton Capacity Limiting System (CLS) was developed for use on counterbalanced lift trucks to prevent abuse of these trucks as a result of overloading. The heart of the system is a hydraulic valve termed the “overload control valve”. This valve reacts to the magnitude of the load moment acting on the truck rather than merely the magnitude of the load. The load moment is defined as the mathematical product of the force exerted by the load and the horizontal distance between the front axle centerline and the vertical projection of the load center of gravity. When the load moment exceeds a predetermined allowable magnitude, the valve prevents further lifting or forward tilting of the mast.

Three cars have been operated for approximately 8000 miles on each of four unleaded gasolines. These gasolines encompassed varied levels of C6-C8 aromatics and varied polynuclear aromatic (PNA) content. Exhaust PNA emissions and lube oil PNA content were measured periodically during the course of mileage accumulation. Results of this study show that increases in both light C6-C8 fuel aromatics and fuel-contained PNAs can result in significantly increased exhaust PNAs. Vehicles meeting increasingly stringent hydrocarbon (HC) and carbon monoxide (CO) emissions standards emit greatly reduced quantities of exhaust PNAs, though the rate of lube oil PNA accumulation appears to be unaffected by emissions control systems. Accumulated lubricating oil mileage was found to correlate with increased PNA emissions with a high level of statistical significance. This may be the result of an observed increase in lube oil PNA content with mileage accumulation.

Paper type friction materials can be used to provide higher dynamic coefficient and better engagement characteristics in wet application, but the softer structure of these products necessitates care for the surface condition of the mating spacer plate if optimum durability is to be obtained. This report covers methods of studying surfaces and relating the observed finish to durability obtained under special dynamometer test conditions. A variety of surface preparations have been investigated including rolled, tumbled, ground, and sanded finishes. Friction material durability was studied as a function of mating plate preparation, roughness, surface profile, and hardness. Relative sensitivity to mating surface of various paper friction formulations is provided. Acknowledging the limitations of the present state-of-the-art, an attempt is made to define spacer requirements for use with these types of friction materials.

The military requirement for a lightweight, air-cooled compression ignition engine family having two members, specifically 10 and 20 hp versions at the rated speed of 3600 rpm, is discussed in this paper. Design and preliminary development programs for such an engine family have been completed, and specifics are related. Development of a practical combustion system for the high rated speed was found to be feasible and is demonstrated on the basis of test data. Endurance data to date indicate that the design life of 6000 h between major overhauls will be attainable. The plan for the future includes additional testing of updated prototype engines as well as further investigations in the areas of noise reduction and control of harmful exhaust emissions.