Marine Engine Lubrication

摘要

Trunk piston marine engine lubrication comprising a major amount of (A) an oil of lubricating viscosity that comprises an oil-soluble ester basestock, or that comprises greater than 0.1 to less than 90 mass % of an oil-soluble ester basestock and, as 50 mass % or more of the remainder of the oil of lubricating viscosity, a high saturates basestock; (B) a minor amount of a metal alkyl salicylate detergent; and (C) greater than 0.1 to less than 10 mass %, of an oil-soluble polyalkenyl-substituted carboxylic acid anhydride, wherein the or at least one polyalkenyl group is derived from a polyalkene having a number average molecular weight of from 200 to 3,000. Asphaltene precipitation in the lubricant composition, caused by the presence of contaminant heavy fuel oil, is prevented or inhibited.

主权项

1. A trunk piston marine engine lubricating oil composition for improving asphaltene handling in use thereof, in operation of the engine when fuelled by a heavy fuel oil, which composition comprises, or is made by admixing:
(A) an oil of lubricating viscosity, in a major amount, which is either an oil-soluble ester basestock (A1); or comprises greater than 0.1 to less than 90 mass % of an oil-soluble ester basestock (A1) and, as 50 mass % or more of the remainder of the oil of lubricating viscosity, a basestock containing greater than or equal to 90% saturates and less than or equal to 0.03% sulphur or a mixture thereof (A2); (B) an oil-soluble metal detergent, in a minor amount; and (C) an oil-soluble polyalkenyl-substituted carboxylic acid anhydride, in a minor amount of from greater than 0.1 to less than 10 mass, the, or at least one, polyalkenyl group being derived from polyalkene having a number average molecular weight of from 200 to 3000.