A lubricant, including, by weight: 80-85 parts of a base oil; 1-2 parts of a methyl-silicone oil; 1-2 parts of polymethacrylate; 2-4 parts of pentaerythritol polyisobutylene succinate; 1-2 parts of di-n-butyl phosphite; 2-3 parts of butylhydroxytoluene; 2-4 parts of an ethylene-propylene copolymer; 1-2 parts of an alkenyl succinate; and 3-5 parts of copper nanoparticles. A method of preparing the lubricant includes: adding the base oil, the methyl-silicone oil, the polymethacrylate, the ethylene-propylene copolymer, the butylhydroxytoluene, the alkenyl succinate to a reactor, and stirring a resulting first mixture under normal temperature and pressure at 300-400 rpm for 3-4 hours, to yield a primary product; and adding the di-n-butyl phosphite, the pentaerythritol polyisobutylene succinate, and the copper nanoparticles to the primary product, and stirring a resulting second mixture at 150-250 rpm for 2-2.5 hours.

A lubricant, including, by weight: 80-85 parts of a base oil; 1-2 parts of a methyl-silicone oil; 1-2 parts of polymethacrylate; 2-4 parts of pentaerythritol polyisobutylene succinate; 1-2 parts of di-n-butyl phosphite; 2-3 parts of butylhydroxytoluene; 2-4 parts of an ethylene-propylene copolymer; 1-2 parts of an alkenyl succinate; and 3-5 parts of copper nanoparticles. A method of preparing the lubricant includes: adding the base oil, the methyl-silicone oil, the polymethacrylate, the ethylene-propylene copolymer, the butylhydroxytoluene, the alkenyl succinate to a reactor, and stirring a resulting first mixture under normal temperature and pressure at 300-400 rpm for 3-4 hours, to yield a primary product; and adding the di-n-butyl phosphite, the pentaerythritol polyisobutylene succinate, and the copper nanoparticles to the primary product, and stirring a resulting second mixture at 150-250 rpm for 2-2.5 hours.

A lubricating oil composition including: a lubricant base oil; (A) a calcium salicylate detergent in an amount of 0.005 to 0.03 mass % in terms of calcium on the basis of the total mass of the composition; (B) a succinimide ashless dispersant in an amount of 0.005 to 0.25 mass % in terms of nitrogen on the basis of the total mass of the composition; (C) a nitrogen-containing antioxidant in an amount of 0.005 to 0.15 mass % in terms of nitrogen on the basis of the total mass of the composition; and optionally (D) a nitrogen-containing friction modifier in an amount of no more than 0.03 mass % in terms of nitrogen on the basis of the total mass of the composition, wherein a total content of any metallic detergent is 0.005 to 0.03 mass % in terms of metal on the basis of the total mass of the composition.

A lubricating oil composition including: a lubricant base oil; (A) a calcium salicylate detergent in an amount of 0.005 to 0.03 mass % in terms of calcium on the basis of the total mass of the composition; (B) a succinimide ashless dispersant in an amount of 0.005 to 0.25 mass % in terms of nitrogen on the basis of the total mass of the composition; (C) a nitrogen-containing antioxidant in an amount of 0.005 to 0.15 mass % in terms of nitrogen on the basis of the total mass of the composition; and optionally (D) a nitrogen-containing friction modifier in an amount of no more than 0.03 mass % in terms of nitrogen on the basis of the total mass of the composition, wherein a total content of any metallic detergent is 0.005 to 0.03 mass % in terms of metal on the basis of the total mass of the composition.

Disclosed is a lubricating oil composition containing a base oil, a viscosity index improver, a molybdenum-based friction modifier, a boron-containing dispersant, and at least two extreme-pressure additives selected from a sulfur-based extreme-pressure additive, a phosphorous-based extreme-pressure additive and a sulfur/phosphorus-based extreme-pressure additive, or a sulfur/phosphorus-based extreme-pressure additive. The base oil is a synthetic oil having a kinematic viscosity at 100° C. of 3 mm.sup.2/s or more and 10 mm.sup.2/s or less, the viscosity index improver is a resin having a number average molecular weight (Mn) of 1,000 or more and 10,000 or less, the mass ratio of boron atoms (B) contained in the boron-containing dispersant to molybdenum atoms (Mo) contained in the molybdenum-based friction modifier, [(B)/(Mo)] is 1 or more and 5 or less, and the mass ratio of sulfur atoms (S) to phosphorus atoms (P) contained in the extreme-pressure additive(s), [(S)/(P)] is 10 or more and 20 or less.

Disclosed is a lubricating oil composition containing a base oil, a viscosity index improver, a molybdenum-based friction modifier, a boron-containing dispersant, and at least two extreme-pressure additives selected from a sulfur-based extreme-pressure additive, a phosphorous-based extreme-pressure additive and a sulfur/phosphorus-based extreme-pressure additive, or a sulfur/phosphorus-based extreme-pressure additive. The base oil is a synthetic oil having a kinematic viscosity at 100° C. of 3 mm.sup.2/s or more and 10 mm.sup.2/s or less, the viscosity index improver is a resin having a number average molecular weight (Mn) of 1,000 or more and 10,000 or less, the mass ratio of boron atoms (B) contained in the boron-containing dispersant to molybdenum atoms (Mo) contained in the molybdenum-based friction modifier, [(B)/(Mo)] is 1 or more and 5 or less, and the mass ratio of sulfur atoms (S) to phosphorus atoms (P) contained in the extreme-pressure additive(s), [(S)/(P)] is 10 or more and 20 or less.

The present invention relates to a composition for lubricating a propulsion system of an electric or hybrid vehicle, comprising at least one base oil and at least one fire retardant corresponding to formula (I)

R.sub.F-L-R.sub.H   (I) in which R.sub.F is a perfluorinated or partially fluorinated group, R.sub.H is a hydrocarbon-based group, and L is a linker.

The invention also relates to the use of at least one fire retardant of formula (I), in a composition for lubricating a propulsion system of an electric or hybrid vehicle, including at least one battery, to give it ignition-resistance properties.

Finally, the invention relates to a process for cooling and fire-protecting a battery of a propulsion system of an electric or hybrid vehicle, comprising at least one step of placing at least one battery, in particular a lithium-ion or nickel-cadmium battery, in contact with a composition according to the invention.

A method for lubricating an internal combustion engine, the method including: supplying a lubricating oil composition to a cylinder of an internal combustion engine, wherein the internal combustion engine has a mean effective pressure of no less than 1.3 MPa, wherein an integrated intensity ratio of peaks of CaO in a X-ray diffraction spectrum of an ash is no more than 16.5%, the ash being obtained by incinerating the lubricating oil composition in an air at 950° C.

A method for lubricating an internal combustion engine, the method including: supplying a lubricating oil composition to a cylinder of an internal combustion engine, wherein the internal combustion engine has a mean effective pressure of no less than 1.3 MPa, wherein an integrated intensity ratio of peaks of CaO in a X-ray diffraction spectrum of an ash is no more than 16.5%, the ash being obtained by incinerating the lubricating oil composition in an air at 950° C.

The invention provides a compressor oil, wherein 2,6-di-tert-butylphenol and tris (2,4-di-tert-butylphenyl) phosphite are added to a base oil having a naphthene content of from 17 to 30% based on the total amount of the base oil, and has a pour point of −25° C. or lower. 2,6-di-tert-butylphenol is effective when it is contained in an amount of from 0.5 mass % to 6.0 mass % based on the total amount of the compressor oil, and tris (2,4-di-tert-butylphenyl) phosphite is effective when it is contained in an amount of from 0.3 mass % to 2.0 mass % based on the total amount of the compressor oil. Furthermore, adding an alkaline earth metal salt of alkylsalicylic acid in combination is even more effective. The amount thereof used is preferably from 0.05 mass % to 2.0 mass %.