Abstract: A trunk piston marine engine lubricant comprises in respective minor amounts (A) an overbased metal hydrocarbyl-substituted hydroxybenzoate detergent system, and (B) a hydrocarbyl-substituted succinic acid anhydride made by halogen- or radical-assisted functionalization processes, where the ratio of succinic anhydride to hydrocarbyl chains is in the range of 1.4 to 4. The lubricant, when used to lubricate such an engine fuelled by heavy fuel oil, exhibits improved control of asphaltene precipitation and deposition on engine surfaces.

Abstract: A trunk piston marine engine lubricant comprises in respective minor amounts (A) an overbased metal hydrocarbyl-substituted hydroxybenzoate detergent system, and (B) a hydrocarbyl-substituted succinic acid anhydride, preferably made by halogen- or radical-assisted fractionalization processes, where the ratio of succinic anhydride to hydrocarbyl chains is in the range of 1.4 to 4. The lubricant, when used to lubricate such an engine fuelled by heavy fuel oil, exhibits improved control of asphaltene precipitation and deposition on engine surfaces.

Abstract: A trunk piston marine engine lubricant comprises in respective minor amounts (A) an overbased metal hydrocarbyl-substituted hydroxybenzoate detergent system, and (B) a hydrocarbyl-substituted succinic acid anhydride made by halogen- or radical-assisted functionalization processes, where the ratio of succinic anhydride to hydrocarbyl chains is in the range of 1.4 to 4. The lubricant, when used to lubricate such an engine fuelled by heavy fuel oil, exhibits improved control of asphaltene precipitation and deposition on engine surfaces.

Abstract: A trunk piston marine engine lubricant comprises in respective minor amounts (A) an overbased metal hydrocarbyl-substituted hydroxybenzoate detergent system, and (B) a hydrocarbyl-subsituted succinic acid anhydride, preferably made by halogen- or radical-assisted fractionalization processes, where the ratio of succinic anhydride to hydrocarbyl chains is in the range of 1.4 to 4. The lubricant, when used to lubricate such an engine fuelled by heavy fuel oil, exhibits improved control of asphaltene precipitation and deposition on engine surfaces.

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.

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.

Abstract: A detergent system that includes (i) an overbased C20-28 alkyl-substituted hydroxybenzoate Ca salt of TBN less than 250 and (ii) an overbased C14-18 alkyl-substituted hydroxybenzoate Ca salt of TBN less than 250, the wt % Ca ratio of (ii) to (i) being more than one, is used in a trunk piston marine lubricant to improve its asphaltene dispersancy when lubricating a medium-speed compression-ignited marine engine fuelled by a heavy fuel oil.

Abstract: Trunk piston marine engine lubrication, when the engine is fueled by heavy fuel oil, is effected by a composition comprising a major amount of an oil of lubricating viscosity containing at least 50 mass % of a Group II basestock, and respective minor amounts of an overbased metal hydrocarbyl-substituted hydroxybenzoate detergent other than such a detergent having a basicity index of less than two and a degree of carbonation of 80% or greater and at least 1 mass % of a hydrocarbyl-substituted carboxylic acid, anhydride, ester or amide thereof. Asphaltene precipitation in the lubricant, caused by the presence of contaminant heavy fuel oil, is prevented or inhibited.

Abstract: A trunk piston marine engine lubricating oil composition for a medium-speed compression-ignited marine engine comprises, in a major amount, an oil of lubricating viscosity containing 50 mass % or more of a Group II basestock, and, in respective minor amounts, (A) an overbased metal hydrocarbyl-substituted hydroxybenzoate detergent having a basicity index of 5.5 or greater, and (B) an overbased metal hydrocarbyl-substituted hydroxybenzoate detergent having a basicity index of 2 or less. The ratio of the mass of metal in detergent (A) to the mass of metal in detergent (B) is 10 or less.

Abstract: A trunk piston marine engine lubricating oil composition for a medium-speed compression-ignited marine engine comprises, in a major amount, an oil of lubricating viscosity containing 50 mass % or more of a Group II basestock, and, in respective minor amounts, (A) an overbased metal hydrocarbyl-substituted hydroxybenzoate detergent having a basicity index of 5.5 or greater, and (B) an overbased metal hydrocarbyl-substituted hydroxybenzoate detergent having a basicity index in the range of 2.1 to 5.4. The ratio of the mass of metal in detergent (A) to the mass of metal in detergent (B) is 1 or less. The trunk piston marine engine lubricating oil composition has a TBN (using ASTM D2896) of 20 to 60.

Abstract: A trunk piston marine engine lubricating oil composition for a medium-speed compression-ignited marine engine comprises, in a major amount, an oil of lubricating viscosity containing 50 mass % or more of a Group II basestock, and, in respective minor amounts, (A) an overbased metal hydrocarbyl-substituted hydroxybenzoate detergent having a basicity index of 5.5 or greater, and (B) an overbased metal hydrocarbyl-substituted hydroxybenzoate detergent having a basicity index of 2 or less. The ratio of the mass of metal in detergent (A) to the mass of metal in detergent (B) is 10 or less.

Abstract: A trunk piston marine engine lubricating oil composition for a medium-speed compression-ignited marine engine comprises, in a major amount, an oil of lubricating viscosity containing 50 mass % or more of a Group II basestock, and, in respective minor amounts, (A) an overbased metal hydrocarbyl-substituted hydroxybenzoate detergent having a basicity index of 5.5 or greater, and (B) an overbased metal hydrocarbyl-substituted hydroxybenzoate detergent having a basicity index in the range of 2.1 to 5.4. The ratio of the mass of metal in detergent (A) to the mass of metal in detergent (B) is 1 or less. The trunk piston marine engine lubricating oil composition has a TBN (using ASTM D2896) of 20 to 60.