Gas-fuelled engine lubricating oil compositions

摘要

A gas-fuelled engine lubricating oil composition having 0.01 to 1.3 % of sulfated ash, which comprises or is made by admixing: (i) a major amount of oil of lubricating viscosity; (ii) a minor amount of a detergent composition consisting essentially of at least one calcium salicylate, wherein the or each salicylate has a TBN in the range from 70 to 245 (iii) 0 to 0.2 mass % of nitrogen, based on the mass of the oil composition, of a dispersant; and (iv) a minor amount of one or more co-additives with the proviso that the oil composition does not contain an anti-oxidant additive.