Marine engine lubrication
AssigneeInfineum International Limited
InventorLaura Gregory
Life of this patent
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Abstract
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.
Claims16
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 %.
Dependencies are inferred from the claim text.