A method of reducing the incidence of deposits on the pistons of a 4-stroke marine diesel engine during operation of the engine when it is fuelled with a marine residual fuel meeting the ISO 8217 2017 fuel standard for marine residual fuels and having a sulphur content of more than 0.1% and less than 0.5% by mass. The method includes the step of lubricating the engine using a lubricating oil composition comprising: a) at least 50% by mass, based on the mass of the composition, of an oil of lubricating viscosity; (b) 5 to 25% by mass, based on the mass of the composition, of an oil-soluble or oil-dispersible alkali metal or alkaline earth metal salicylate detergent, or a mixture of two or more oil-soluble or oil-dispersible alkali metal or alkaline earth metal salicylate detergents; (c) 0.1 to 10% by mass, based on the mass of the composition of one or more oil-soluble or oil-dispersible ashless dispersants; and optionally, (d) 0.1 to 10% by mass, based on the mass of the composition of a polyalkylene-substituted succinic anhydride.

A method of reducing the incidence of deposits on the pistons of a 4-stroke marine diesel engine during operation of the engine when it is fuelled with a marine residual fuel meeting the ISO 8217 2017 fuel standard for marine residual fuels and having a sulphur content of more than 0.1% and less than 0.5% by mass. The method includes the step of lubricating the engine using a lubricating oil composition comprising: a) at least 50% by mass, based on the mass of the composition, of an oil of lubricating viscosity; (b) 5 to 25% by mass, based on the mass of the composition, of an oil-soluble or oil-dispersible alkali metal or alkaline earth metal salicylate detergent, or a mixture of two or more oil-soluble or oil-dispersible alkali metal or alkaline earth metal salicylate detergents; (c) 0.1 to 10% by mass, based on the mass of the composition of one or more oil-soluble or oil-dispersible ashless dispersants; and optionally, (d) 0.1 to 10% by mass, based on the mass of the composition of a polyalkylene-substituted succinic anhydride.

Lubricating composition comprising (i) base oil and (ii) a Verkade base compound having the formula (1): wherein R.sup.1, R.sup.2 and R.sup.3 are each independently selected from hydrogen and saturated or unsaturated, straight chain or branched, C.sub.1-C.sub.22 alkyl groups. The lubricating composition of the present invention exhibits improved base number retention and oxidative stability, particularly in the presence of a biofuel such as fatty acid alkyl ester.

##STR00001##

The disclosed technology provides a lubricating composition comprising an oil of lubricating viscosity and 0.01 wt % to 10 wt % of an oxyalkylated aromatic polyol compound, wherein the aromatic compound has at least one alkoxy group represented by −OR.sup.1 group, R.sup.1 is hydroxyalkyl, or a (poly)ether group, and either: at least one hydroxyl group, or at least one alkoxy group represented by —OR.sup.1 group, where R.sup.1 is alkyl, or a (poly)ether group, or at least one oxyalkyl group represented by —OR.sup.1, where R.sup.1 is hydroxyalkyl or a (poly)ether group. The disclosed technology further relates to a method of lubricating a mechanical device (such as an internal combustion engine) with the lubricating composition. The disclosed technology further relates to the use of the oxyalkylated aromatic polyol compound in the lubricating composition to a passenger car internal combustion engine at least one of (i) control of fuel economy, (ii) control of corrosion, (iii) cleanliness, and (iv) control of bore wear.

A lubricating oil detergent composition comprises an overbased calcium sulfonate and a low ash detergent, which low ash detergent is metal free and comprises the reaction product of an acidic organic compound such as an alkylated salicylic acid, a boron compound and an amine component.

A lubricating oil composition for an internal combustion engine, the composition including: a lubricating base oil comprising at least one mineral base oil or at least one synthetic base oil or any combination thereof, the lubricating base oil having a kinematic viscosity at 100° C. of 4.0 to 4.5 mm.sup.2/s and a NOACK evaporation loss at 250° C. of no more than 15 mass %; (A) a calcium-containing metallic detergent in an amount of no less than 1000 mass ppm and less than 2000 mass ppm in terms of calcium on the basis of the total mass of the composition; and optionally (C) a viscosity index improver in an amount of less than 1 mass % on the basis of the total mass of the composition.

A lubricating oil composition for an internal combustion engine, the composition including: a lubricating base oil comprising at least one mineral base oil or at least one synthetic base oil or any combination thereof, the lubricating base oil having a kinematic viscosity at 100° C. of 4.0 to 4.5 mm.sup.2/s and a NOACK evaporation loss at 250° C. of no more than 15 mass %; (A) a calcium-containing metallic detergent in an amount of no less than 1000 mass ppm and less than 2000 mass ppm in terms of calcium on the basis of the total mass of the composition; and optionally (C) a viscosity index improver in an amount of less than 1 mass % on the basis of the total mass of the composition.

A lubricating oil composition for internal combustion engines is disclosed. The composition exhibits a lower coefficient of friction and improved cleaning properties without causing a deterioration in thermal and oxidation stability.

A lubricating oil composition for internal combustion engines is disclosed. The composition exhibits a lower coefficient of friction and improved cleaning properties without causing a deterioration in thermal and oxidation stability.

An additive package is disclosed for preparing an automotive crankcase lubricating oil composition for an internal combustion engine. The additive package is made by admixing: (i) 50 mass % or less of an oil of lubricating viscosity; (ii) 50 mass % or less of at least one overbased metal detergent, preferably at least one overbased metal hydroxybenzoate detergent; (iii) 50 mass % or less of an oil-soluble block or graft co-polymer of at to least one polymeric block A which is derived from a hydroxycarboxylic acid and at least one polyalkylene block B which is a residue of a polyalkylene glycol, and (iv) optionally, at least one further additive selected from a dispersant, an antioxidant and/or an antiwear agent.

The additive package includes less than 2.00 mass % preferably less than 1.50 mass %, of a friction modifier which is a monoester of a C.sub.5 to C.sub.30 carboxylic acid and which is free of nitrogen.

Component (ii) is preferably an overbased metal hydroxybenzoate detergent.

Component (iii) acts as a friction modifier and can be used as a replacement for a friction modifier such as glycerol monooleate.

The additive package exhibits improved stability.