The present disclosure relates to lubricant compositions for use on engine components. The lubricant compositions include, by volume: 30 to 50% graphite in alcohol solution; 0.1 to 5% surfactant; and 40 to 70% water. The present disclosure also relates to processes for preparing lubricant compositions and methods of using such compositions.

The present disclosure relates to lubricant compositions for use on engine components. The lubricant compositions include, by volume: 30 to 50% graphite in alcohol solution; 0.1 to 5% surfactant; and 40 to 70% water. The present disclosure also relates to processes for preparing lubricant compositions and methods of using such compositions.

A defoaming agent obtainable by a process, the process including the step of: (i) polymerizing (B) at least one defoaming agent monomer in (A) a polymerization solvent under coexistence of (C) a polymer soluble in the polymerization solvent.

A lubricating oil composition including: a lubricant base oil; (A) a first defoaming agent obtainable by a process, the process including the step of: polymerizing (b) at least one defoaming agent monomer in (a) a polymerization solvent under coexistence of (c) a polymer soluble in the polymerization solvent; and (B) a second defoaming agent being a silicone defoaming agent.

Disclosed is a lubricating oil composition capable of inhibiting vibrations or noises generated between a pulley and a chain or between a pulley and a belt in a CVT or the like, while increasing an intermetallic friction coefficient, the composition containing a base oil, an alkaline earth metal-based detergent (A), a phosphite ester (B1), a phosphate ester amine salt (B2), an acidic phosphate ester (B3), an aliphatic monoamine (C1), and an aromatic monoamine (C2).

Disclosed is a lubricating oil composition capable of inhibiting vibrations or noises generated between a pulley and a chain or between a pulley and a belt in a CVT or the like, while increasing an intermetallic friction coefficient, the composition containing a base oil, an alkaline earth metal-based detergent (A), a phosphite ester (B1), a phosphate ester amine salt (B2), an acidic phosphate ester (B3), an aliphatic monoamine (C1), and an aromatic monoamine (C2).

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 package comprising a borated calcium detergent, wherein the detergent package provides a calcium content in the composition of at least 0.12 mass %, based on the total mass of the composition, and wherein the borated calcium detergent provides a boron content in the composition of at least 100 ppmm, based on the total mass of the composition. Optionally, the composition comprises a first detergent comprising a calcium detergent, and a second detergent comprising a borated calcium detergent.

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 package comprising a borated calcium detergent, wherein the detergent package provides a calcium content in the composition of at least 0.12 mass %, based on the total mass of the composition, and wherein the borated calcium detergent provides a boron content in the composition of at least 100 ppmm, based on the total mass of the composition. Optionally, the composition comprises a first detergent comprising a calcium detergent, and a second detergent comprising a borated calcium detergent.

Hydrogenated polymers with a radial structure having a core made up of calixarenes of the general formula (I), to the core of which is linked a number P of hydrogenated linear polymer segments selected from: hydrogenated homopolymers or co-polymers of conjugated dienes; or hydrogenated co-polymers of said conjugated dienes and monoalkenyl arenes, and mixtures thereof said formula (I) in which: R.sub.1, R.sub.2, R.sub.3 and R.sub.4 are independently selected from hydrogen; a group containing carbon and hydrogen; a group also containing heteroatoms in addition to carbon and hydrogen; a group also containing silicon in addition to carbon, hydrogen and heteroatoms; one of the two substituents R.sub.5 and R.sub.6 is hydrogen, while the other may be hydrogen or alkyl, with a number of carbon atoms between 1 and 6, preferably methyl and ethyl; n is an integer in the range between 4 and 16.

##STR00001##

A defoaming agent including a polymer, the polymer including a repeating unit represented by the following general formula (1); and a repeating unit represented by the following general formula (3): ##STR00001##
wherein in the general formula (1), X.sup.1 is a repeating unit obtainable by polymerization of a first ethylenic unsaturated group; Y.sup.1 is a side chain including a linear or branched polysiloxane structure, the polysiloxane structure having a polymerization degree of 5 to 300; and Z.sup.1 is a linking group linking the repeating unit X.sup.1 and the side chain Y.sup.1; ##STR00002##
wherein in the general formula (3), X.sup.2 is a repeating unit obtainable by polymerization of a second ethylenic unsaturated group, Y.sup.2 is a C.sub.1-30 hydrocarbyl side chain; and Z.sup.2 is a linking group linking the repeating unit X.sup.2 and the side chain Y.sup.2.