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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.

THIS authors sees a need, in the near future, for commercial vehicles with engines of 1000 to 1200 hp - powerplants that yield high outputs but require limited space. He sees an immediate need for more and more horsepower per cubic inch of piston displacement and per unit of space for the engine. He directs attention to six design potentials which may supply the answer: (1) the gas turbine; (2) supercharging; (3) aircooled diesels; (4) higher engine speeds; (5) 2-stroke diesel improvement; (6) compound engines. He also links the future development of the internal-combustion engine with basic improvement of components through simplification, calling for the elimination of extraneous gadgetry.

The heavy-duty truck industry has seen the need for a change in the concept of transmission design for many years. Several improvements have been made and others attempted, but greater improvement is needed to match the engine's delivery to the vehicle's demand. Driver performance can be improved and fatigue reduced by lowering the effort and skill required to make smooth, consistent starts and ratio changes. This paper discusses a solution to this need in the design and development of a semi-automatic, pneumatically controlled, constant mesh transmission.

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.

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 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.

This paper describes the concept and design of the Caterpillar “G” series motor grader transmission and transmission controls. Comments on vehicle performance, power train, and oil system requirements are included. Countershaft directional clutches are combined with six or eight speed planetary ranges for this family of articulated motor graders. The pilot-operated hydraulic control provides smooth rapid gear ratio changes and “inching” modulation for the pressure lubed directional clutches.

ISO and SAE static sound power test methods are currently used for construction machinery. The European Economic Community sound committee has been developing a drive-by or simulated work cycle test method using a hemispherical array of microphones. The EEC method is inconsistent due to the changing test surface (moist sand) and the variables of outdoor testing: temperature, wind, and precipitation. The in-place-dynamic test method described provides a disciplined way to evaluate machines with moving track or wheels and operating hydraulic systems. The machine is slightly elevated, resting on stands, so that the wheels are off the ground or the tractor weight is off the track chain. Data obtained from track-type tractor, track-type loader, and wheel loader machines supports the validity of using an indoor, in-place-dynamic test instead of a moving, outdoor test. Results also show that using sound intensity instrumentation permits the option of testing in an untreated, indoor facility.

This Paper: 1. Shows that the present spherical rod end manufacturer's rotational tests, which are intended to select the best bearing material, do not necessarily select the best materials for the push/pull linkage requirements of earthmoving machinery. 2. Emphasizes the need to perform push/pull comparative testing as defined in SAE J1367 on spherical rod ends to determine acceptable materials for earthmoving equipment application. This test is in contrast to rotational testing presently being performed by spherical rod end manufacturers.

For some time, Caterpillar Tractor Co. has been marketing a new transmission control system for wheel-tractor scrapers and off-highway trucks. The new system is composed of an electronic microprocessor control box coupled with an individual clutch modulation hydraulic control. This system has resulted in increased vehicle productivity, improved reliability and serviceability, decreased complexity, and increased commonality of parts. This paper describes the concept, design, and test and evaluation process used to develop the new controls before production.

Caterpillar recently introduced its first backhoe loader - a significant extension to the existing product line of construction equipment. It is a highly versatile machine entering a well-developed marketplace. This paper describes design considerations, the development program, and vehicle design features associated with the 416 Backhoe Loader.

THE CATERPILLAR FOLDED CORE RADIATOR IS A NEW RADIATOR FOR VEHICLES AND STATIONARY ENGINE APPLICATIONS. THE MAJOR OBJECTIVES OF THIS DESIGN ARE TO GIVE THE USER AN INCREASED VALUE COOLING SYSTEM BY REDUCING RADIATOR REPAIR COSTS AND IMPROVING AIR-SIDE PLUGGING RESISTANCE. AS WELL AS PROVIDE THE VEHICLE DESIGNER WITH INCREASED APPLICATION DESIGN FLEXIBILITY. THIS IS TO BE ACCOMPLISHED WHILE MAINTAINING PERFORMANCE AND LIFE GOALS ASSOCIATED WITH THE CONVENTIONAL RADIATOR. THE FOLDED CORE IS A MODULAR DESIGN HAVING THE MODULES INSTALLED AT AN ANGLE TO THE FAN AIR STREAM RESULTING IN THE FOLDED APPEARANCE. COMMON MODULE SIZES ARE USED ACROSS THE MANY RADIATOR APPLICATIONS REDUCING INVENTORY REQUIREMENTS AT THE ASSEMBLY PLANT AND PARTS DEPOTS AND INCREASING INDIVIDUAL MODULE PRODUCTION VOLUME. THIS RADIATOR DESIGN IS REVIEWED FROM CONCEPT TO PRODUCTION.