| abstract |
A low sulfur marine fuel tubular piston diesel engine lubricating oil composition comprising or formed by mixing (A) an oil of lubricating viscosity in an amount of 50% by mass or more of the composition; and in respective amounts of less than 50% by mass of the composition, (B) a base excess metal detergent comprising a metal salt of a surfactant selected from a hydrocarbyl-substituted phenol, a hydrocarbyl-substituted sulfonic acid hydrocarbyl and a hydrocarbyl-substituted hydroxybenzoic acid; (C) a zinc dihydrocarbyldithiophosphate in an amount of 50 to 500 ppm by weight in terms of P atoms as measured by ASTM D5185; (D) optionally, an amino antioxidant in an amount of up to 400, preferably in an amount of 200 (preferably, when present, 10 to 200) ppm by weight in terms of N atoms as measured by ASTM D5762; and (E) a borated dispersant containing no ash in an amount of 10 to 500 ppm by weight in terms of B content as measured by ASTM D5185, the composition having a TBN of 5 to less than 20, preferably 8 to 15 mg KOH / g as measured by ASTM D2896. |