A lubricating oil composition, a method of reducing low-speed pre-ignition (LSPI) in a direct-injected spark-ignited internal combustion engine, and a use of a lubricant composition to reduce LSPI events in such an engine. Preferably, the composition comprises a detergent comprising an overbased calcium detergent having a total base number (TBN) of at least 150, wherein the lubricating oil composition has a calcium content of at least 0.08 wt. %, based on the weight of the lubricating oil composition, and wherein the lubricating oil composition has a silicon content of at least 12 ppm by weight, based on the weight of the lubricating oil composition.

Lubricant compositions including an additive composition and methods for its use in engines that produce soot. The lubricant composition contains a base oil and an additive composition having (a) at least 0.05 percent by weight of a first dispersant that is a reaction product of A) a hydrocarbyl-dicarboxylic acid or anhydride, and B) at least one polyamine; and (b) at least 0.05 percent by weight, both based on a total weight of the lubricant composition, of a second dispersant that is a reaction product of A) a hydrocarbyl-dicarboxylic acid or anhydride, and B) at least one polyamine, wherein the reaction product is post-treated with C) an aromatic carboxylic acid, an aromatic polycarboxylic acid, or an aromatic anhydride wherein all carboxylic acid or anhydride groups are attached directly to an aromatic ring, and/or D) a non-aromatic dicarboxylic acid or anhydride having a number average molecular weight of less than about 500.

A refrigerator oil according to one embodiment of the present invention contains: a base oil containing an oxygen-containing organic compound; a polyphosphate ester compound; and a metal salt of an organic carboxylic acid having 6 to 60 carbon atoms.

The present technology is related to amide or ester containing quaternary ammonium salts having a hydrocarbyl substituent of number average molecular weight less 300, and additive packages having such quaternary ammonium salts and improved stability.

In one aspect, lubricant compositions are described herein. In some embodiments, a lubricant composition described herein comprises a grease and milled metal sulfide particles dispersed in the grease. In other cases, a lubricant composition described herein comprises a grease, polytetrafluroethylene particles, zinc dithiophosphate, and molybdenum dialkyldithiocarbamate, wherein the polytetrafluroethylene particles, zinc dithiophosphate, and molybdenum dialkyldithiocarbamate are dispersed in the grease.

A lubricating oil composition, a method of reducing low-speed pre-ignition (LSPI) in a direct-injected spark-ignited internal combustion engine, and a use of a lubricant composition to reduce LSPI events in such an engine. Preferably, the composition comprises a detergent comprising an overbased calcium detergent having a total base number (TBN) of at least 150, wherein the lubricating oil composition has a calcium content of at least 0.08 wt. %, based on the weight of the lubricating oil composition, and wherein the lubricating oil composition has a silicon content of at least 12 ppm by weight, based on the weight of the lubricating oil composition.

An overbased magnesium sulfonate detergent is made by (A) preparing a mixture of a sulfonic acid or salt with a magnesium oxide, water, a C.sub.1-C.sub.5 alkanol, a hydrocarbon solvent, and a combination of a polyisobutene succinic anhydride of molecular weight (M.sub.w) 500 to 1500 g mol.sup.1 and a salicylic acid as first and second promoters; and (B) carbonating the mixture with an acidic gas to form the overbased magnesium sulfonate.

Disclosed is an oil soluble polyester composition, suitable for use as a dispersant in lubricating oils. The oil soluble polyester composition is prepared by reacting (a) a hydrocarbyl-substituted succinic acylating agent and (b) a di-hydroxyalkyl-substituted tertiary amine compound selected from a N,N-di-hydroxyalkyl-substituted tertiary monoamine and a N,N-di-hydroxyalkyl-substituted tertiary diamine.

Disclosed is an oil soluble polyester composition, suitable for use as a dispersant in lubricating oils. The oil soluble polyester composition is prepared by reacting (a) a hydrocarbyl-substituted succinic acylating agent and (b) a di-hydroxyalkyl-substituted tertiary amine compound selected from a N,N-di-hydroxyalkyl-substituted tertiary monoamine and a N,N-di-hydroxyalkyl-substituted tertiary diamine.

An additive package for an internal combustion engine crankcase lubricating oil composition, which additive package comprises or is made by admixing: (A) 5-99.4 mass % based on the mass of the additive package, of a diluent oil of lubricating viscosity; and (B) the following additives: (B1) 0.1-10 mass % of a polymeric friction modifier, on an active matter basis, based on the mass of the additive package, which polymeric friction modifier is the reaction product of (a) a functionalised polyolefin, (b) a polyether, (c) a polyol, and (d) a monocarboxylic acid chain terminating group (B2) 0.5 to 10 mass % on an active matter basis, based on the mass of the additive package of one or more ashless organic friction modifiers that include a polar terminal group covalently bonded to a monomeric oleophilic hydrocarbon chain.