The invention is directed to a zinc-free lubricating composition for an internal combustion engine containing a phosphorus anti-wear agent, an ashless antioxidant, and a metal-free basic detergent. The lubricating composition provides wear protection, deposit control, and improved acid control with reduced levels of metal-containing additives.

The invention relates to the use of at least one phosphorus compound, which is free of sulfur and has no amine function, as an anti-wear and extreme-pressure additive in a lubricant composition for a propulsion system of an electric or hybrid vehicle. The invention also relates to the use of a lubricant composition comprising at least one phosphorus compound, which is free of sulfur and has no amine function, as an anti-wear and extreme-pressure additive, for lubricating and optionally cooling a propulsion system of an electric or hybrid vehicle, in particular for lubricating and cooling the electric motor and the power electronics of an electric or hybrid vehicle.

A lubricant additive composition and lubricant composition are provided that include one or more friction modifier compounds and antiwear compounds. Methods of lubricating moving metal surfaces of a machine are also provided.

A lubricant additive composition and lubricant composition are provided that include one or more friction modifier compounds and antiwear compounds. Methods of lubricating moving metal surfaces of a machine are also provided.

A lubricating oil composition including a base oil (X) having a tertiary carbon atom at a content of 8.0 at % or more based on the total carbon of hydrocarbons and an antioxidant (Y) having an amine-based antioxidant (A), a phenol-based antioxidant (B), and a phosphor-based antioxidant (C). The amine-based antioxidant (A) includes a diphenylamine compound (A1) represented by the following general formula (a1):

##STR00001##

where R.sup.a1 and R.sup.a2, na1 and na2 are defined in the disclosure.

A lubricating oil composition including a base oil (X) having a tertiary carbon atom at a content of 8.0 at % or more based on the total carbon of hydrocarbons and an antioxidant (Y) having an amine-based antioxidant (A), a phenol-based antioxidant (B), and a phosphor-based antioxidant (C). The amine-based antioxidant (A) includes a diphenylamine compound (A1) represented by the following general formula (a1):

##STR00001##

where R.sup.a1 and R.sup.a2, na1 and na2 are defined in the disclosure.

An additive composition for limiting the chemical degradation of hydrocarbonaceous liquids due to nitrogen dioxide contamination at elevated temperature comprises the combination of an ionic liquid composed of a cation and a boron- and halogen-free, multi-functional anion and a detergent additive, the combination of ionic liquid and detergent serving to inhibit the nitration of hydrocarbonaceous liquid components that initiates degradation.

An additive composition for limiting the chemical degradation of hydrocarbonaceous liquids due to nitrogen dioxide contamination at elevated temperature comprises the combination of an ionic liquid composed of a cation and a boron- and halogen-free, multi-functional anion and a detergent additive, the combination of ionic liquid and detergent serving to inhibit the nitration of hydrocarbonaceous liquid components that initiates degradation.

An ionic liquid composed of nitrogen-free cations and aromatic halogen- and boron-free anions is useful as an additive to prolong the service life of hydrocarbonaceous liquids exposed to nitrogen dioxide contamination, and to provide friction and wear reduction.

An ionic liquid composed of nitrogen-free cations and aromatic halogen- and boron-free anions is useful as an additive to prolong the service life of hydrocarbonaceous liquids exposed to nitrogen dioxide contamination, and to provide friction and wear reduction.