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A new family of heavy duty diesel engines, the 3400 Series, has been developed by Caterpillar Tractor Co. The family includes Inline 6 cylinder, V-8 and V-12 engines covering the 270-750 horsepower range. Stringent program objectives were established in the areas of durability, reliability, commonality, flexibility and serviceability within defined limits of cost and weight. Design, development and manufacturing planning were closely coordinated to ensure economical manufacturing with high volume tooling. This paper deals with the design, development and certain aspects of engine applications.

THE HYDRAULIC SYSTEMS for the Caterpillar “G” Series Motor Graders were designed to provide for maximum operator comfort, ease of operation, and optimum control of the vehicle and implements. The use of high pressure closed center systems on these machines produces rapid system response and high hydraulic horsepower to the implement cylinders and motors, and operates with minimum size control components. Components were designed to meet specific system requirements for functional performance, reliability of operation, size and placement on the machine. System goals were met through the use of a variable displacement pressure compensated pump, controlled flow four-way implement valves, and a hydrostatic steering system.

This paper traces the development of lubricants for Diesel engine and heavy duty service from the time the mobile Diesel became a production entity in this country. Beginning with a background of lubricants found acceptable for large Diesel engines in marine and stationary service, the trend in the supply of lubricants in subsequent automotive practices in the early 1930's led to difficulties in ring sticking, bearing corrosion and cylinder scuffing in the moderate speed, heavy duty engine seeking commercial favor at that time. The attempts to solve these problems, both as to engine improvements and lubricant selection, are reviewed historically. The logical development of additive oils followed the pattern of alloy steel achievements.

A cooperative research program has been completed evaluating the impact of fuel composition (volatility, aromatics and sulfur) on the combustion and emissions performance of a Caterpillar 3406B turbo-charged diesel engine, which is representative of diesel truck engines of the late 1980s. Tests included both steady-state and transient operation measuring regulated and unregulated emissions. The fuel set was blended using only commercially available refinery stocks typical of those which could be considered for use in distillate fuel. The compositions of the blends were selected so that direct measurements of the individual effects of 10% and 90% distillation temperatures, aromatic content, and sulfur content could be made independently. Engine combustion performance data indicated that all fuels operated satisfactorily; aromatic content was as high as 50% and cetane number as low as 39. Further, the cetane number did not predict the engine measured ignition delay in this program.

The effect of altitude on the performance of two turbocharged prechamber diesel engines and one direct-injection diesel engine has been studied in a test cell. One prechamber engine was tested at altitudes up to 16,000 ft. The data from these tests are presented and compared with performance at standard conditions. Using the data, an analytical method of predicting the performance of turbocharged diesel engines at altitude has been developed. An iterative computer program, using part-load data taken at standard conditions, is used for the prediction. Comparison is made with the simulated altitude data and with other calculation methods.

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.