For many years additives have been used to treat fuels to improve the performance of engines. A novel approach has been evaluated to using fuel as an additive delivery system for marine engines, large and small. In the past it has been shown that chemical exchange takes place from the gas/liquid phase in the combustion chamber to the liquid phase on the cylinder liner. Examples of this phenomenon are: The observed fuel economy when friction modifiers are used in gasoline. The effect of fuel sulphur on bore polish in diesel engines. The observation of some piston ring corrosion with the use of some fuel lubricity additives. Additives used in fuels tend to be non-volatile, soluble in both fuel and base oil, and polar, hence they will partially adsorb into lubricant films on metal surfaces. Studies have been made to evaluate how much additive will adsorb onto the cylinder liner. Modelling has been used to calculate a number of key factors, first is the oil film thickness with distance along the piston stroke, where work suggests a film thickness of between 15 and 18 microns. Another key factor is the residence time of the lubricant film on the liner wall, which has been estimated at between 15 and 25 minutes. Equally as important is the rate of adsorption of additive into the lubricant film on the liner. Following these theoretical studies additive systems were developed and tested in a range of marine engines, fuelled by both marine diesel and heavy fuel oil. A range of effects were evaluated, including lube oil consumption in medium speed engines running on marine diesel and cylinder oil feed rate in two stroke engines running on heavy fuel oil. The additive systems have been evaluated in both bench engines and in the field and results are reported.
Systemic lubrication - delivery of performance through fuel and lubricant
2004
7 Seiten, 4 Bilder, 4 Tabellen, 2 Quellen
Conference paper
Storage medium
English
Systematic lubrication - delivery of performance through fuel and lubricant
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