A lubricating composition comprises a major amount of an oil of lubricating viscosity and 0.01 to 25 percent by mass, based on the mass of the composition of an oil-soluble copolymer. The copolymer comprises units (a) and units (b):
N(COR.sup.1)CH.sub.2CH.sub.2(a)
N(COR.sup.2)CH.sub.2CH.sub.2CH.sub.2(b)
wherein the polymer carries an inorganic or organic nucleophilic polymerisation terminating group (t), and an initiator group (i) connected to the N atom of a repeat unit (a) or (b), the initiator group (i) being effective to initiate the polymerisation of linear, branched or cyclic hydrocarbyl moieties. R.sup.1 and R.sup.2 are the same or different and comprise a single or a mixture of linear, branched or cyclic hydrocarbyl groups having 1-50 carbon atoms, some or all having 12-50 carbon atoms, or of at least one macro-monomeric hydrocarbyl group with more than 50 carbon atoms.

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 ashless dispersant. The ashless dispersant may be selected from succinimide compounds prepared from aliphatic or aromatic amines.

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 ashless dispersant. The ashless dispersant may be selected from succinimide compounds prepared from aliphatic or aromatic amines.

A lubricating composition comprises a major amount of an oil of lubricating viscosity and 0.01 to 25 percent by weight, based on the weight of the composition, of a poly(2-oxazoline) polymer. The polymer has the repeat unit:
N(COR.sup.1)CH.sub.2CH.sub.2
wherein the number of repeat units (n) in the polymer is an integer between 4 and 1000, such as between 4 and 500. The polymer carries an inorganic or organic nucleophilic polymerisation terminating group (t), and an initiator group (i) connected to the N atom of a repeat unit, the initiator group (i) being effective to initiate the polymerisation of linear, branched or cyclic hydrocarbyl moieties. At least 5% of the total number of the groups R.sup.1 in the polymer comprise alkenyl groups having between 15 and 20 carbon atoms.

A polyisobutylene-substituted hydroxyaromatic compound and derivatives thereof which are suitable for use as additives in lubricating compositions. The polyisobutylene-substituted hydroxyaromatic compound may include the reaction product of a hydroxyaromatic compound with a polyisobutylene having a number average molecular weight of 150 to 800.

A coffee lubricant having nanoparticles is provided. It consists of 36 to 40 wt % of glycerin, 1 to 7 wt % of gum arabic, 0.3 to 1.3 wt % of nanoparticles, and remaining part of coffee biofuel. In which, the nanoparticles are CuO. The coffee biofuel is extracted from coffee dregs and has a viscosity of 60 to 70 cSt at a temperature of 40 degrees Celsius. It can reduce the friction coefficient and operating temperature. In addition, it can replace the mineral oil.

The disclosed technology provides a lubricating composition comprising an oil of lubricating viscosity and a detergent comprising a polyolefin-substituted hydroxy-aromatic carboxylic acid or salt thereof, wherein the polyolefin is derived from a branched alkene having at least 4 carbon atoms and wherein the polyolefin has a number average molecular weight of 150 to 800. The invention further relates to a method of lubricating a mechanical device with the lubricant composition.

A lubricating oil composition comprising at least 50 percent by mass, based on the mass of the composition of an oil of lubricating viscosity and 0.01 to 25 percent by mass, based on the mass of the composition of a polymer comprising units (a) and one or both units (b) and (c):

N(COR.sup.1)(CH.sub.2).sub.x(a)

NH(CH.sub.2).sub.y(b)

N(CH.sub.2CH.sub.2-k(CH.sub.3).sub.kCOOR.sup.2)(CH.sub.2).sub.z (c) where the total number (n) of units (a), (b) and (c) is an integer between 4 and 500; wherein x, y and z are independently 2 or 3; wherein k is zero or 1. The polymer shows good solubility in the lubricating oil and provides friction modification. A method of synthesising a polymer is also disclosed.

An antioxidant package composition including a combination of: (i) at least one hindered phenolic antioxidant, and (ii) at least one polyether sulphide; a lubricant composition including: (a) the antioxidant package composition and (b) at least one base oil; a process for preparing the antioxidant package composition; and a process for preparing the lubricant composition.

Provided are a lubricating oil composition containing a mineral oil (1) having a kinematic viscosity at 100 C. of 2 mm.sup.2/s or more and less than 2.5 mm.sup.2/s, and a polymethacrylate (2) having a functional group containing an oxygen atom in the molecule while having a specific structural, unit, which satisfies both high viscosity index and high shear stability, and a lubrication method and a transmission using the lubricating oil composition.