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The International Lubricant Standardization and Approval Committee (ILSAC) GF-2 specification requires Passenger Car Motor Oils to provide enhanced fuel economy in a modern low friction engine as measured by the ASTM Sequence VIA This paper details fundamental studies of the effect of zinc dithiophosphate, both type and level, on fuel economy as measured by this low friction engine The Sequence VIA was found to be very sensitive to both the level of zinc dithiophosphate and the type of alcohol functionality associated with it Increasing the level of zinc dithiophosphate was found to enhance fuel economy as measured by this test particularly in the SAE 10W-30 viscosity grade Secondary zinc dithiophosphates outperformed both primary and aryl types This paper will discuss these findings, as well as report on some fundamental studies using 31P-NMR and surface film analysis to determine the fate of zinc dithiophosphate during the course of this test

This paper deals with the performance of both semisynthetic and full synthetic automotive gear lubricants in laboratory axle efficiency tests. The development and use of laboratory models for the purpose of predicting lubricant related fuel economy benefits in actual field service is explained. Using these laboratory techniques, improvements in axle efficiency provided by selected synthetic based lubricant formulations are demonstrated.

The conversion of spark ignited and compression ignited engines to run on natural gas is established technology Engines have also been designed and built specifically for natural gas These engines have been used primarily in stationary applications with relatively constant operating conditions More recently, environmental pressures and economic considerations have made the use of natural gas attractive for transportation applications The urban transit bus population is particularly well suited to compressed natural gas fueling The basic engine designs for stationary natural gas service and conventionally fueled (diesel and gasoline) transportation service are similar Differences in operating conditions and maintenance practices have resulted in two distinct lubricant product groups Stationary natural gas engine lubricants tend to be high viscosity monograde formulations with a low ash content Lubricants for conventionally-fueled transportation applications are frequently multigrades with considerably higher ash content The lubricant needs for natural gas in transportation applications may not be adequately met with the lubricant product groups widely usable for stationary natural gas or conventionally fueled transportation Lubricant products have been designed to combine features identified as desirable for natural gas fueling and the needs of transportation usage The performance of these products is supported by laboratory engine data

In our earlier work [1], an investigation was conducted to study lubricant formulation effects, engine type and mode of engine operation on the composition and nature of diesel soot and its interactions with the crankcase lubricant. Tests were run in two types of heavy duty diesel engines the Mack EM6-285 and the GM 6.2L. Part 2 studies the impact of oil composition on the surface and bulk chemistry of soot and on the ability of the fluid to handle soot produced in the GM 6.5L engine. The study also determined what portion of lubricant viscosity growth is related to bulk oil oxidation versus soot contamination. A statistically designed experiment was developed to examine the effects of dispersant level dispersant type, antioxidant level, and detergent metal type on average roller follower shaft wear, viscosity growth and other measured responses. The effect of run order on these measurements is also studied. Key results of this study are as follows.