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The role that lubricating oils play is, first of all, to reduce energy loss and keep the wear and seizure to a minimum, or, in a broader sense, to improve the friction characteristics. Resistance to deterioration and prevention of rust development on metals are demanded as secondary functions. The time during which lubricating oil retains its ability to prevent any possible damage to a body in motion should be considered as its lifetime. Many functions that are provided by base oil alone are insufficient; therefore, special additives are dissolved in them. The additives for lubricating oils are of many types, and their functions are diverse and many. Those additives that are used with the purpose of improving friction characteristics are generally called oiliness improvers or friction modifiers. In this study, the protective additive's layers formed on rubbed surfaces of pins, plates and discs were investigated using pin-on-disc and reciprocating pin-on-plate test rigs. Wear tracks were examined using optical and electron microscopy with X-ray diffraction analysis. [ABSTRACT FROM AUTHOR]

Two 5W-30 synthetic-base phosphorus containing (commercial) and phosphorus-free (P-free) crankcase oils were tested for engine performance characteristics, engine emissions and poisoning effects of oil additives on a three-way catalytic converter using engine dynamometer. The emission data of the two oils taken during engine operation were compared in the absence and presence of the catalytic converter. Surface characterization was used to determine the poisoning catalyst effect accumulated from the oil additives in the ceramic washcoat. Oil analyses were also used to examine the condition of the lubricant occurred during engine performance testing operation. The experimental engine performance tests indicated that the catalytic converter diminished the torque and power for the commercial and P-free oils, whereas the specific fuel consumption increased for both oils in the presence of the catalytic converter. [ABSTRACT FROM AUTHOR]

Additives are incorporated in engine oils to improve existing desirable properties of base stocks and to impart new specific properties required by modern engines. The additives include antioxidants, detergents, dispersants, corrosion and rust inhibitors, viscosity index improvers, pour point depressants, foam inhibitors and tribological agents. In this study, the effect of boron oil fortifier added into the base oil on friction coefficient and pressure distribution was investigated between sliding surfaces of engine journal bearings. Experiments were performed firstly using only base oil at different speeds and loads. Then, this test was repeated with different concentration ratio of 1, 3, 5 and 10 percent commercial boron additive. [ABSTRACT FROM AUTHOR]