Broughten, J. L.
Manager, Union Oil Company of California, Los Angeles, Calif.
Moore, C. C.
Supervisor, Union Oil Company of California, Los Angeles, Calif.
Pages: 10 Published: Jan 1957
There has been considerable activity in the field of economy fuels for locomotive diesel engines. However, little attention has been directed toward the study of crankcase lubricants for use with these fuels. It is well known that fuels and lubricants have interrelated effects on engine deposits and wear. Experience has indicated that joint studies of fuels and lubricants are needed to obtain the most savings from economy fuels. For example, a knowledge of these factors must be used in setting up overhaul and maintenance procedures. The current interest in residual fuels seems to justify a review of some of the ways in which changes in fuel quality have affected the lubrication of diesel locomotives in the past. It seems certain that this same pattern will confront the railroads in the future as they make still further changes in their fuels to obtain economies. In the early days of diesel locomotives, the engine builders were faced with the problem of adapting their power plants to the varying speed and loads of railroad operation. For this fairly severe service, and because diesel engine reliability had not been fully proved, the engine builders recommended the use of high-quality diesel fuels. These were fuels of high cetane numbers, low sulfur contents, and low boiling ranges. Many railroads operating diesel engines with low brake mean effective pressures (BMEP), obtained satisfactory performance with medium viscosity index, nondetergent lubricants when these fuels were used. Most of these lubricating oils contained some type of oxidation inhibitor. During this period it was found that the source of the lubricating oil base stock and the method of refining affected the performance of nondetergent oils as regards valve, ring, piston, and air port deposits. The oxidation stability of the lubricant and the nature of the combustion deposits formed were found to be of great importance. Even when using high-grade fuels, engines lubricated with poor quality nondetergent oils showed excessive deposits. During these early stages of locomotive diesel operation a great deal of effort was spent in improving and modifying engine design. The initial development of detergent-type oils was being carried out during this same period. On account of the rapid changes occurring in both fields, detailed knowledge of the fuel-lubricant relationship was difficult to obtain.
Paper ID: STP46896S