MARINE ENGINE LUBRICATION

摘要

A trunk piston lubricating oil composition of TBN 20 to 60 comprising (A) a high saturates low sulphur oil of lubricating viscosity in a major amount; (B) an overbased metal hydroxybenzoate detergent additive; (C) a polyisobutene succinic anhydride additive (1-7 mass %); and (D) a meta-linear pentadecyl phenol additive (10.1 to 10 mass %), the weight ratio of (D) to (C) being less than 1 and the combined treat rate of (B), (C) and (D) being 5 to 30%. The composition is useful to improve asphaltene dispersancy when lubricating a medium-speed compression-ignited marine engine fueled by a heavy fuel oil.

主权项

1. A trunk piston marine engine lubricating oil composition having a TBN 20 to 60 mg KOH/g, for a medium-speed four-stroke compression-ignited marine engine, comprising or made by admixing:
(A) an oil of lubricating viscosity in a major amount containing greater than or equal to 90% saturates and less than or equal to 0.03% sulphur; (B) a detergent additive, in a minor amount, comprising one or more overbased metal hydrocarbyl-substituted hydroxybenzoates; (C) an additive, in an amount of 1 to 10 mass %, comprising one or more polyisobutene succinic anhydrides derived from polyisobutene having a number average molecular weight of 200 to 3000; and (D) an additive, in an amount of 0.1 to 10 mass %, comprising one or more sterically unhindered meta linear pentadecyl phenols, wherein the weight ratio of (D) to (C) is less than 1, and the combined treat rate of said hydroxybenzoate(s), anhydride(s) and phenol(s) is in the range of 5 to 30 mass %.