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Gearing load spectra data collected under actual working conditions help a designer predict the fatigue life of power train components. Considerable time was required in the past to collect and reduce these data to a form suitable for design use. A vehicle mounted instrumentation system consisting of a strain gaged shaft, a shaft encoder-slip ring assembly, and an amplitude distribution analyzer, was developed which performs load measurements. At the test's conclusion, it provides a spectrum analysis in printed histogram form.

THIS paper presents results which will answer many of the problems facing an engine manufacturer in the selection of the most suitable types and sizes of superchargers to use with a line of engines. Although performance curves of production model diesels are available, decisions are still needed in choosing peak supercharging pressures, drive means, and size and effectiveness of intercoolers, if any. The author describes the use of a typical model to determine response to variation in intake and exhaust conditions, resulting in data which will assist in evaluating engine potentials with any system of supercharging. Thus, supercharger selection for a particular line of engines is aided by knowledge of engine characteristics as a second-stage compressor.

The quality of a product is as perceived by the user and includes the net effect of the quality of the original product and of available product support. Engineering objectives should include improvement of support capabilities, regardless of the exquisiteness of the design.

SETTING ratings for diesel engines takes laboratory testing and field experience for critical parameters such as smoke, piston temperature, and exhaust temperature. Rating is based upon theoretical considerations, plus the approval of the engine itself. Factors in rating considerations include a knowledge of the application of the engine, and whether its use is to be intermittent or continuous. Ratings by the manufacturer are not always accepted by the engine user, however. The user will run the engine at the load most profitable for him, which may be above or below that recommended by the manufacturer.

A new two-speed converter drive, six-speed mechanical drive transmission was designed for a 14 cu yd tractor scraper to provide an efficient and easily controlled power train. Included with a description of the system is a review of the development history, along with a summary of some new features utilized in this design.

A single-shaft, simple-cycle gas turbine engine has been developed to power 200 kw alternators for standby power and for applications where heat is needed. The engine was designed to be sold and serviced by distributors of earthmoving and industrial machinery. Where feasible, design practices of industrial piston engine powered generator sets were incorporated to facilitate installations of combinations of engine types, and to limit novel and unfamiliar features of the basic turbine engine to those that were considered essential. Individual components and complete engines, initially developed by a research group, have been subjected to a wide variety of laboratory tests to measure performance and develop reliability.

A new 2-ring piston package has been developed which has proven successful in internal combustion engines. The need for a compact piston arrangement is discussed along with the steps followed to arrive at excellent oil economy. The paper presents other advantages related to cost savings, lower wear, and reduced engine friction. The paper discusses applications of the compact piston package along with its advantages in designing compact engines.

Fatigue failure of machine components subjected to high contact pressures is rapidly becoming recognized as a serious design limitation. Confusion has resulted from grouping three distinct types of contact fatigue failure under the term “pitting” A Geared Roller Test Machine is described that reproduced each of the three modes of failure. The stress-life relationships obtained for rollers tested under conditions of rolling plus sliding correlated well with actual gear performance. The sensitivity of the test to changes in material, micorstructure, and processing variables is demonstrated.