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Many vehicle and engine test studies have shown that the fuel efficiency of automobiles can be improved by reducing friction between moving parts. Typically, organic friction modifiers such as glycerol monooleate (GMO) or metal containing friction modifiers such as molybdenum dithiocarbamate (MoDTC) have been added to engine oils to reduce boundary friction and improve fuel efficiency. These traditional friction modifiers act by forming either a self-assembled organic film (in the case of GMO) or a Mo-disulfide chemical film (in the case of MoDTC). More recently, the ability of inorganic tungsten disulfide (WS2) nanoparticles to reduce boundary friction has been described. Martin has proposed that WS2 nanoparticles are transported into a contact zone where they are compressed and peel open like an onion to form a film. In this study, oil-soluble inorganic nanoparticles containing cerium (Ce) and zinc (Zn) have been synthesized.

Manganese oxide deposits which are exclusively in the form of Mn3O4, a benign form of manganese, are introduced in the exhaust stream from use of MMT, an octane-enhancing, emission-reducing fuel additive. The physical and chemical effect of these deposits on catalytic converters has generated some controversy in the literature. In this paper, we will focus on the effects that manganese oxide deposits have on catalytic converters. The physical effect of these deposits on the morphology of the converters was investigated by B.E.T surface area measurements, scanning electron microscopy (SEM), and x-ray fluorescence (XRF). The chemical effect was investigated with tests using both slave-engine dynamometers and a pulse-flame combustor to probe for differences in catalyst performance. Data from an extensive vehicle fleet which was tested according to a program designed in consultation with the EPA and the automobile industry will be presented.

The effects of fuel composition and engine operating parameters on high-pressure, direct injection gasoline (DIG) injector plugging and deposit formation have been studied. The engine used was a conventional dual-sparkplug, 2.2-liter Nissan engine modified for direct injection using one of the spark plug holes. The engine was run under 20% rich conditions to accelerate deposit formation. A ten-fuel test matrix was designed around T90, sulfur level, and olefin levels indicated in the European gasoline specifications for year 2000. The gasolines, containing no detergents, were formulated using refinery stream blends to match the specified targets. Injector flow loss was monitored by fuel flow to the engine and monitoring oxygen sensors on each of the four cylinders. The impact of fuel composition on deposit formation and injector plugging is discussed. Injector flow loss was strongly influenced by injector tip temperature.