A lubricating oil composition for an internal combustion engine has a HTHS viscosity at 150° C. of 2.55-2.84 mPa.Math.s and includes: (A) a lubricating base oil including (a) mineral base oil(s) and/or (a) synthetic base oil(s), and having a kinematic viscosity at 100° C. of 3.8-4.6 mm.sup.2/s; (B) 1000-2000 mass ppm, in terms of metal content, of a metallic detergent including (a) metal salicylate detergent(s), and delivering 10 mmol/kg of total salicylate soap base per kilogram of the composition; (C) 1.0 to 4.0 mass % of a comb-shaped poly(meth)acrylate having a Mw of 350,000-1,000,000 and a PDI of ≤4.0; and (D) 100-1000 mass ppm, in terms of nitrogen, of a succinimide dispersant including (i) (a) non-modified succinimide dispersant(s) and/or (ii) (a) boric acid-modified succinimide dispersant(s), wherein the (i) and the (ii), in total, deliver 70 mass % of total nitrogen content of the component (D).

A lubricating oil composition for an internal combustion engine has a HTHS viscosity at 150° C. of 2.55-2.84 mPa.Math.s and includes: (A) a lubricating base oil including (a) mineral base oil(s) and/or (a) synthetic base oil(s), and having a kinematic viscosity at 100° C. of 3.8-4.6 mm.sup.2/s; (B) 1000-2000 mass ppm, in terms of metal content, of a metallic detergent including (a) metal salicylate detergent(s), and delivering 10 mmol/kg of total salicylate soap base per kilogram of the composition; (C) 1.0 to 4.0 mass % of a comb-shaped poly(meth)acrylate having a Mw of 350,000-1,000,000 and a PDI of ≤4.0; and (D) 100-1000 mass ppm, in terms of nitrogen, of a succinimide dispersant including (i) (a) non-modified succinimide dispersant(s) and/or (ii) (a) boric acid-modified succinimide dispersant(s), wherein the (i) and the (ii), in total, deliver 70 mass % of total nitrogen content of the component (D).

Provided herein are polyolefin dispersants, as well as methods for producing polyolefin dispersants. The polyolefin dispersants can be defined by the formula below

##STR00001##

where R.sup.x is cationic initiator residue; R.sup.a is a polyolefin group; R.sup.1 and R.sup.2 are each, independently in each —(CR.sup.1R.sup.2) unit, H, alkyl, alkoxy, or alkylaryl; R.sup.3 and R.sup.4 are each, independently, H, alkyl, or alkoxy; m is an integer from 1 to 20; n is an integer from 1 to 6; r is an integer from 1 to 4; Y is a polyvalent amine linker comprising one or more tertiary amines, wherein the polyvalent amine linker does not include a primary amine or a secondary amine; and A is absent, or comprises a dispersive moiety.

Provided herein are polyolefin dispersants, as well as methods for producing polyolefin dispersants. The polyolefin dispersants can be defined by the formula below

##STR00001##

where R.sup.x is cationic initiator residue; R.sup.a is a polyolefin group; R.sup.1 and R.sup.2 are each, independently in each —(CR.sup.1R.sup.2) unit, H, alkyl, alkoxy, or alkylaryl; R.sup.3 and R.sup.4 are each, independently, H, alkyl, or alkoxy; m is an integer from 1 to 20; n is an integer from 1 to 6; r is an integer from 1 to 4; Y is a polyvalent amine linker comprising one or more tertiary amines, wherein the polyvalent amine linker does not include a primary amine or a secondary amine; and A is absent, or comprises a dispersive moiety.

Provided herein are polyolefin dispersants, as well as methods for producing polyolefin dispersants. The polyolefin dispersants can be defined by the formula below ##STR00001##
where R.sup.x is cationic initiator residue; R.sup.a is a polyolefin group; R.sup.1 and R.sup.2 are each, independently in each (CR.sup.1R.sup.2) unit, H, alkyl, alkoxy, or alkylaryl; R.sup.3 and R.sup.4 are each, independently, H, alkyl, or alkoxy; m is an integer from 1 to 20; n is an integer from 1 to 6; r is an integer from 1 to 4; Y is a polyvalent amine linker comprising one or more tertiary amines, wherein the polyvalent amine linker does not include a primary amine or a secondary amine; and A is absent, or comprises a dispersive moiety.

Provided herein are polyolefin dispersants, as well as methods for producing polyolefin dispersants. The polyolefin dispersants can be defined by the formula below ##STR00001##
where R.sup.x is cationic initiator residue; R.sup.a is a polyolefin group; R.sup.1 and R.sup.2 are each, independently in each (CR.sup.1R.sup.2) unit, H, alkyl, alkoxy, or alkylaryl; R.sup.3 and R.sup.4 are each, independently, H, alkyl, or alkoxy; m is an integer from 1 to 20; n is an integer from 1 to 6; r is an integer from 1 to 4; Y is a polyvalent amine linker comprising one or more tertiary amines, wherein the polyvalent amine linker does not include a primary amine or a secondary amine; and A is absent, or comprises a dispersive moiety.

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.

Disclosed is a dispersant composition, suitable for use in lubricating oils. The dispersant composition is a reaction product of (i) a polyalkenyl succinimide post-treated with a post-treating agent selected from the group consisting of an organic carbonate, an epoxide, a lactone, a hydroxyaliphatic carboxylic acid, and combinations thereof; and (ii) an acylating agent.

Disclosed is a dispersant composition, suitable for use in lubricating oils. The dispersant composition is a reaction product of (i) a polyalkenyl succinimide post-treated with a post-treating agent selected from the group consisting of an organic carbonate, an epoxide, a lactone, a hydroxyaliphatic carboxylic acid, and combinations thereof; and (ii) an acylating agent.

A lubricating oil composition comprises a major amount of an oil of lubricating viscosity and a minor amount of an unsymmetrical bis-succinimide, or a mixture of unsymmetrical bis-succinimides, of the structure (I): ##STR00001##
wherein one of R.sub.1 and R.sub.2 is a polyisobutylene group having a weight average molecular weight of 400 to 5,000, as determined by GPC with reference to linear polystyrene standards, and the other of R.sub.1 and R.sub.2 is a hydrocarbon group made by the metallocene-catalysed polymerisation of an -olefin feedstock; and x is from 1 to 10 and is the same for all molecules of structure (I), or an average of all molecules of structure (I) in a mixture of molecules of structure (I).