A lubricating composition suited to use for lubricating a hydraulic system includes an oil of lubricating viscosity and a compound comprising a polyolefin-substituted bridged hydroxyaromatic compound or metal salt thereof, wherein the wherein the polyolefin is derived from a isobutylene having a number average molecular weight of 150 to 800.

Disclosed herein is a process for preparing a sulfurized non-overbased calcium phenate detergent having a reduced content of un-sulfurized alkyl-substituted phenol and its salt. The process steps involve adding an organic solvent to the detergent, wherein the organic solvent has a boiling point of equal or above the boiling point of the un-sulfurized alkyl-substituted phenol. Distilling the organic solvent from the detergent to reduce the content of the un-sulfurized alkyl-substituted phenol.

A lubricating composition includes an oil of lubricating viscosity and a compound comprising a protected mercaptophenol. The protected mercaptophenol includes a mercapto group in which the hydrogen is substituted with a substituent of at least 5 carbons. The substituent is selected from hydroxy-substituted hydrocarbyl groups, poly(ether) groups, hydrocarbyl groups, and mixtures and salts thereof.

A lubricating composition includes an oil of lubricating viscosity and a compound comprising a protected mercaptophenol. The protected mercaptophenol includes a mercapto group in which the hydrogen is substituted with a substituent of at least 5 carbons. The substituent is selected from hydroxy-substituted hydrocarbyl groups, poly(ether) groups, hydrocarbyl groups, and mixtures and salts thereof.

The disclosed technology provides alkylphenol-containing detergent having at least one unit (a) of an alkyl-substituted phenol wherein the alkyl group is derived from oligomers of an olefin compound containing 3 to 8 carbon atoms, wherein the polyolefin-derived alkyl group comprises at least 30 mol percent of an olefin with 4 or more carbon atoms. The invention further relates to a method of lubricating a mechanical device with the lubricant composition.

The disclosed technology provides alkylphenol-containing detergent having at least one unit (a) of an alkyl-substituted phenol wherein the alkyl group is derived from oligomers of an olefin compound containing 3 to 8 carbon atoms, wherein the polyolefin-derived alkyl group comprises at least 30 mol percent of an olefin with 4 or more carbon atoms. The invention further relates to a method of lubricating a mechanical device with the lubricant composition.

The invention is directed to a method for reducing low speed pre-ignition events in a spark-ignited direct injection internal combustion engine by supplying to the sump a lubricant composition which contains an oil of lubricating viscosity and an overbased sodium detergent. The metal overbased detergent may be selected from sulfonate detergents, phenate detergents, and salicylate detergents, including sulfonate detergents with a metal ratio of at least 5.

The invention is directed to a method for reducing low speed pre-ignition events in a spark-ignited direct injection internal combustion engine by supplying to the sump a lubricant composition which contains an oil of lubricating viscosity and an overbased sodium detergent. The metal overbased detergent may be selected from sulfonate detergents, phenate detergents, and salicylate detergents, including sulfonate detergents with a metal ratio of at least 5.

The disclosed technology provides a lubricating composition comprising an oil of lubricating viscosity and 0.2 wt % to 10 wt % of a salt of a hydroxyl functional aromatic compound. The disclosed technology further relates to a method of lubricating a mechanical device with the lubricant composition.

The disclosed technology provides a lubricating composition comprising an oil of lubricating viscosity and 0.2 wt % to 10 wt % of a salt of a hydroxyl functional aromatic compound. The disclosed technology further relates to a method of lubricating a mechanical device with the lubricant composition.