Lubricating oil composition having resistance to engine deposits and varnish formation - Patents.com

Abstract

A lubricating oil composition comprising greater than 50 weight percent of a base oil of lubricating viscosity, and an additive composition comprising an amount of one or more zinc dialkyldithiophosphates (ZDDP compounds) and an amount of one or more viscosity modifiers, wherein the amount of phosphorus (P) in weight percent provided to the lubricating oil composition by the one or more ZDDP compounds divided by the amount of the one or more viscosity modifiers (VM) in weight percent based on a total weight of the lubricating oil composition is a P / VM quotient of greater than about 0.0075. The lubricating oil composition can improve resistance to engine deposits and extend the oil drain interval of an internal combustion engine.

Description

[Technical field]

[0001] The present disclosure relates to engine lubricants that are resistant to engine deposits and varnish formation. In particular, the present disclosure relates to lubricants and methods for improving the resistance of the lubricants to engine deposits and varnish formation in engines or other machine parts lubricated with the lubricants. The lubricants of the present disclosure are useful as internal combustion engine oils or in other applications where the lubricants are subjected to thermal and oxidative conditions. [Background technology]

[0002] Lubricating oils are an important part of modern vehicle design for engine operation and protection. During the use of hydrocarbon-based lubricants, autoxidation occurs. This process leads to the formation of acids and thickening of the oil. In more severe cases, oil-insoluble sludge and varnish may form, causing poor lubrication, reduced fuel economy, and increased wear. Antioxidants are additives that are typically incorporated into lubricant formulations to delay the onset of autoxidation and minimize its effects.

[0003] Oil varnishing can be the result of a complex series of events. Specifically, molecules in the oil stream can be destroyed via chemical, mechanical, and / or thermal processes. For example, chemical processes can include oxidation of the oil. Oxidation can be accelerated by heat and / or the presence of metal particulates therein. Mechanical processes can include "shearing," where oil molecules can be torn apart as they pass between moving mechanical surfaces. Thermal processes can include pressure-induced thermal degradation due to high pressures and temperatures. Electrostatic charges can also cause localized thermo-oxidative oil degradation. Other processes and combinations may exist but are not fully understood at this time.

[0004] Thus, there is a need for an additive package for a lubricating oil composition that limits both the formation of oil varnish and the damage caused thereby during use, particularly in valve lifters, piston rings, piston skirts, valve covers, and positive crankcase ventilation (PCV) valves. Summary of the Invention

[0005] The present disclosure meets the above-mentioned need for an additive package for a lubricating oil composition that limits both the formation of oil varnish and the damage caused thereby during use, particularly in valve lifters, piston rings, piston skirts, valve covers, and PCV valves.

[0006] The present disclosure may be explained by the following passages. 1. A lubricating oil composition comprising greater than 50 wt. % of a base oil of lubricating viscosity; and an additive composition comprising: and an additive composition comprising an amount of one or more zinc dialkyl dithiophosphates (ZDDP compounds) and an amount of one or more viscosity modifiers, wherein the amount of phosphorus (P) in weight percent provided to the lubricating oil composition by the one or more ZDDP compounds divided by the amount of the one or more viscosity modifiers (VM) in weight percent based on a total weight of the lubricating oil composition is a P / VM quotient of greater than about 0.0075. 2. The lubricating oil composition according to paragraph 1, wherein the P / VM quotient is greater than about 0.0077, or greater than about 0.0077 and less than 0.1, or greater than about 0.0077 and less than 0.03, or greater than about 0.0077 and less than 0.02. 3. The lubricating oil composition according to sentences 2 or 3, wherein the P / VM quotient may be greater than about 0.0075 and the amount of VM is less than 14 wt.%, or the P / VM quotient may be greater than about 0.0077 and the amount of VM is less than 13 wt.%, or the P / VM quotient may be greater than about 0.0077 and less than 0.03 and the amount of VM is less than 12 wt.%. 4. The lubricating oil composition of any one of sentences 1-3, wherein the P / VM quotient may be greater than about 0.0075 and the amount of P may be at least 0.064 wt.%, or the P / VM quotient may be greater than about 0.0077 and the amount of P may be at least about 0.064 wt.%, or the P / VM quotient may be greater than about 0.0077 and less than 0.03 and the amount of P may be at least 0.064 wt.% and less than 0.15 wt.%. 5. The lubricating oil composition of any one of paragraphs 1-4, wherein the one or more ZDDP compounds may be present in the lubricating oil composition in an amount of from about 0.01 wt. % to about 15 wt. %, or from about 0.01 wt. % to about 10 wt. %, or from about 0.05 wt. % to about 5 wt. %, or from about 0.1 wt. % to about 3 wt. %, based on the total weight of the lubricating oil composition. 6. The lubricating oil composition of any one of sentences 1-5, wherein the amount of the one or more viscosity modifiers can be greater than about 0.5 wt.%, or from about 0.5 wt.% to about 30 wt.%, or from about 0.9 wt.% to about 25 wt.%, or from about 1.0 wt.% to about 25 wt.%, or from about 1.0 wt.% to about 18 wt.%, the amount being based on the total weight of the lubricating oil composition. 7. The lubricating oil composition according to any one of paragraphs 1 to 6, wherein the one or more ZDDP compounds can be derived from one or more secondary alkyl alcohols having an alkyl group having from 3 to 8 carbon atoms. 8. The lubricating oil composition according to any one of paragraphs 1 to 7, wherein the one or more ZDDP compounds can be derived from a secondary alkyl alcohol selected from the group consisting of isopropyl alcohol, amyl alcohol, and methyl isobutyl carbinol. 9. The lubricating oil composition according to any one of paragraphs 1 to 8, wherein the one or more ZDDP compounds can be derived from two or more secondary alkyl alcohols. 10. The lubricating oil composition according to any one of paragraphs 1 to 9, wherein the one or more ZDDP compounds can be derived from one or more primary alkyl alcohols each having an alkyl group having from 3 to 8 carbon atoms. 11. The lubricating oil composition according to paragraph 10, wherein the alkyl group of the one or more primary alkyl alcohols can have a branch at a beta carbon relative to the hydroxyl group. 12. The lubricating oil composition according to any one of paragraphs 1 to 11, wherein the one or more ZDDP compounds can be derived from one or more primary alkyl alcohols selected from the group consisting of n-propyl alcohol, isopropyl alcohol, isobutyl alcohol, n-butyl alcohol, 2-butanol, n-pentyl alcohol, hexanol, methyl isobutyl carbinol, isohexanol, n-heptanol, isoheptanol, octanol, amyl alcohol, and 2-ethylhexanol. 13. The lubricating oil composition according to any one of paragraphs 1 to 12, wherein the one or more ZDDP compounds can be derived from two or more primary alkyl alcohols. 14. The lubricating oil composition according to any one of paragraphs 1 to 13, wherein the one or more ZDDP compounds can be a mixture of at least one ZDDP compound derived from 100% primary alcohol and at least one ZDDP compound derived from 100% secondary alcohol. 15. The lubricating oil composition of paragraph 14, wherein the mixture may comprise a ZDDP compound derived from 100% primary alcohol in an amount contributing 15 to 500 ppmw zinc to the lubricating oil composition, and a ZDDP compound derived from 100% secondary alcohol in an amount contributing 100 to 1000 ppm zinc to the lubricating oil composition, based on the total weight of the lubricating oil composition, or the mixture comprises a ZDDP compound derived from 100% primary alcohol in an amount contributing 100 to 400 ppmw zinc to the lubricating oil composition, and a ZDDP compound derived from 100% secondary alcohol in an amount contributing 200 to 800 ppm zinc to the lubricating oil composition, based on the total weight of the lubricating oil composition. 16. The lubricating oil composition of any one of paragraphs 1 to 15, wherein the one or more ZDDP compounds may be derived from a mixture of primary and secondary alcohols contributing 200 to 1400 ppmw of zinc to the lubricating oil composition, based on the total weight of the lubricating oil composition, or are derived from a mixture of primary and secondary alcohols contributing 500 to 1200 ppmw of zinc to the lubricating oil composition, based on the total weight of the lubricating oil composition. 17. One or more ZDDP compounds are a) one or more ZDDP compounds derived from a mixture of primary and secondary alcohols; i) one or more ZDDP compounds derived from 100% primary alcohols, or ii) The lubricating oil composition according to any one of paragraphs 1 to 16, which may be in a mixture with any one or more ZDDP compounds derived from 100% secondary alcohols. 18. The lubricating oil composition according to any one of paragraphs 1 to 17, wherein the one or more ZDDP compounds can be a mixture of one or more ZDDP compounds derived from a mixture of primary and secondary alcohols and one or more ZDDP compounds derived from 100% primary alcohol. 19. The lubricating oil composition according to any one of paragraphs 1 to 18, wherein the one or more ZDDP compounds can be a mixture of one or more ZDDP compounds derived from a mixture of primary and secondary alcohols and one or more ZDDP compounds derived from 100% primary alcohol. 20. The lubricating oil composition according to any one of paragraphs 1 to 19, wherein the one or more ZDDP compounds can be derived from a molar ratio of one or more primary alkyl alcohols to one or more secondary alkyl alcohols of from 100:20 to 50:50. 21. The lubricating oil composition according to any one of paragraphs 1 to 20, wherein the one or ZDDP compounds may have a zinc to phosphorus molar ratio of 1.08 to 1.2. 22. The lubricating oil composition according to any one of paragraphs 1 to 21, wherein one or more viscosity modifiers may be non-dispersant viscosity modifiers. 23. The lubricating oil composition according to paragraph 22, wherein the non-dispersant viscosity modifier can be a hydrocarbon polymer. 24. The lubricating oil composition according to paragraph 23, wherein the hydrocarbon polymer can be a polyolefin which is an ethylene-alphaolefin copolymer or a diene polymer. 25. Polyolefin is a mixture of ethylene and C3-C 2825. The lubricating oil composition according to paragraph 24, which may be an oil soluble or dispersible copolymer of alpha-olefins, or ethylene and C3-C8 alpha-olefins, or ethylene and C3-C6 alpha-olefins, or ethylene and C3-C4 alpha-olefins. 26. The lubricating oil composition according to paragraphs 24 or 25, wherein the polyolefin may be an ethylene propylene copolymer which is a random copolymer. 27. The lubricating oil composition according to any one of paragraphs 24 to 26, wherein the polyolefin may be a diene polymer comprising isoprene, butadiene, 2,3-dimethyl-1,3-butadiene, chloroprene, 1,3-butadiene, piperylene, 1-4 hexadiene, ethylidene norbornene, vinyl norbornene, 4-vinylcyclohexene, dicyclopentadiene, and mixtures thereof. 28. The lubricating oil composition according to any one of paragraphs 24 to 27, wherein the polyolefin may have a weight average molecular weight (Mw) as determined by gel permeation chromatography using polystyrene standards in the range of from about 7,000 g / mol to about 500,000 g / mol, or from about 20,000 g / mol to about 400,000 g / mol, or from about 100,000 g / mol to about 300,000 g / mol. 29. The lubricating oil composition according to any one of paragraphs 24 to 28, wherein the polyolefin may have a polydispersity (Mw / Mn) in the range of about 1.5 to about 10, or about 1.5 to about 3.0, or about 1.7 to about 3.0, or about 2.0 to about 2.5. 30. The lubricating oil composition according to any one of paragraphs 24 to 29, wherein the polyolefin may have a shear stability index (SSI), as measured using test method ASTM-D6278, of from about 3 to about 60, or from about 5 to about 50, or from about 15 to about 40, or from about 20 to about 35. 31. The lubricating oil composition according to any one of paragraphs 1 to 30, which may further comprise at least one additive selected from the group consisting of dispersants, antioxidants, antiwear agents, antifoam agents, molybdenum-containing compounds, titanium-containing compounds, phosphorus-containing compounds, pour point depressants, and diluent oils. 32. The lubricating oil composition of any one of paragraphs 1 to 31, wherein the lubricating oil composition is capable of providing an average Engine Varnish Test (ASTM D8256) result of 8.6 minutes or more, or 8.7 minutes or more, or from 8.7 minutes to about 15 minutes. 33. A method for extending the oil drain interval of an internal combustion engine, comprising adding to the engine a lubricating oil composition according to any one of sentences 1 to 32, and operating the engine. 34. A method for reducing engine deposits in an internal combustion engine, comprising adding to the engine a lubricating oil composition according to any one of sentences 1 to 32, and operating the engine. 35. A process for improving the engine deposit resistance of an engine oil, comprising incorporating an amount of one or more zinc dialkyldithiophosphates (ZDDP compounds) and an amount of one or more viscosity modifiers into a base oil to form an engine oil, wherein the amount of phosphorus (P) in weight percent provided to the lubricating oil composition by the one or more ZDDP compounds divided by the amount of the one or more viscosity modifiers (VM) in weight percent based on a total weight of the lubricating oil composition is a P / VM quotient of greater than about 0.0075.

[0007] The following definitions are provided to clarify the meaning of certain terms used herein.

[0008] The terms "oil composition," "lubrication composition," "lubricating oil composition," "lubricating oil," "lubricant composition," "lubricating composition," "fully formulated lubricant composition," "lubricant," "crankcase oil," "crankcase lubricant," "engine oil," "engine lubricant," "motor oil," and "motor lubricant" are considered to be synonymous and fully interchangeable terms referring to a finished lubricant product comprising a major amount of a base oil plus a minor amount of an additive composition.

[0009] As used herein, the terms "additive package", "additive concentrate", "additive composition", "engine oil additive package", "engine oil additive concentrate", "crankcase additive package", "crankcase additive concentrate", "motor oil additive package", "motor oil concentrate" are considered to be synonymous and fully interchangeable terms that refer to that portion of a lubricating oil composition that excludes a major amount of a base oil stock blend. The additive package may or may not include a viscosity index improver or a pour point depressant.

[0010] The term "overbased" refers to metal salts, such as metal salts of sulfonates, carboxylates, salicylates, and / or phenates, in which the amount of metal present exceeds the stoichiometric amount. Such salts may have a conversion level of more than 100% (i.e., such salts may contain more than 100% of the theoretical amount of metal required to convert the acid to its "standard" or "neutral" salt). The expression "metal ratio", often abbreviated as MR, is used to indicate the ratio of the total chemical equivalents of the metal in an overbased salt to the chemical equivalents of the metal in a neutral salt, according to known chemical reactivity and stoichiometry. In standard or neutral salts, the metal ratio (MR) is 1, whereas in overbased salts, the MR is greater than 1. These are commonly referred to as overbased, hyperbased, or superbased salts, and may be salts of organic sulfur acids, carboxylic acids, salicylates, and / or phenols.

[0011] As used herein, the term "hydrocarbyl substituent" or "hydrocarbyl group" is used in its normal sense, which is well known to those skilled in the art. Specifically, it refers to a group having a carbon atom directly attached to the remainder of the molecule and having a predominantly hydrocarbon character. Each hydrocarbyl group is independently selected from hydrocarbon substituents, the substituted hydrocarbon substituents containing one or more of halo, hydroxyl, alkoxy, mercapto, nitro, nitroso, amino, pyridyl, furyl, imidazolyl, oxygen, and nitrogen, and no more than two non-hydrocarbon substituents are present for every 10 carbon atoms in the hydrocarbyl group.

[0012] As used herein, the term "hydrocarbylene substituent" or "hydrocarbylene group" is used in its ordinary sense, which is well known to those skilled in the art. Specifically, it refers to a group that is directly attached to the remainder of the molecule by carbon atoms at two locations in the molecule and has a predominantly hydrocarbon character. Each hydrocarbylene group is independently selected from divalent hydrocarbon substituents, where the substituted divalent hydrocarbon substituents include halo, alkyl, aryl, alkylaryl, arylalkyl, hydroxyl, alkoxy, mercapto, nitro, nitroso, amino, pyridyl, furyl, imidazolyl, oxygen, and nitrogen, and no more than two non-hydrocarbon substituents are present for every 10 carbon atoms in the hydrocarbylene group.

[0013] As used herein, the term "weight percent" means the percentage that the recited component represents relative to the weight of the entire composition, unless expressly stated otherwise.

[0014] The terms "soluble", "oil-soluble" or "dispersible" used herein may, but do not necessarily, indicate that a compound or additive is soluble, dissolvable, miscible, or can be suspended in oil in any proportion. However, the terms mean that they are, for example, soluble, suspendable, soluble, or stably dispersible in oil to a sufficient degree to exert their intended effect in the environment in which the oil is used. Furthermore, if desired, the incorporation of other additives may also allow the incorporation of higher levels of the specific additive.

[0015] As employed herein, the term "TBN" is used to indicate the total base number in mg KOH / g as measured by the methods of ASTM D2896 or ASTM D4739 or DIN 51639-1.

[0016] The term "alkyl" as used herein refers to straight, branched, cyclic, and / or substituted saturated chain moieties of about 1 to about 100 carbon atoms.

[0017] The term "alkenyl" as used herein refers to straight, branched, cyclic, and / or substituted unsaturated chain moieties of about 3 to about 10 carbon atoms.

[0018] The term "aryl" as used herein refers to mono- and polycyclic aromatic compounds that can contain alkyl, alkenyl, alkylaryl, amino, hydroxyl, alkoxy, halo substituents, and / or heteroatoms including, but not limited to, nitrogen, oxygen, and sulfur.

[0019] The lubricants, combinations of components, or individual components herein may be suitable for use in various types of internal combustion engines. Suitable engine types may include, but are not limited to, heavy duty diesel, passenger car, light duty diesel, medium speed diesel, or marine engines. The internal combustion engine may be a diesel fueled engine, a gasoline fueled engine, a natural gas fueled engine, a biofuel engine, a mixed diesel / biofuel-fueled engine, a mixed gasoline / biofuel-fueled engine, an alcohol fueled engine, a mixed gasoline / alcohol fueled engine, a compressed natural gas (CNG) fueled engine, or a mixture thereof. The diesel engine may be a compression ignition engine. The gasoline engine may be a spark ignition engine. The internal combustion engine may also be used in combination with electric or battery power sources. Engines so configured are usually known as hybrid engines. The internal combustion engine may be a two-stroke, four-stroke, or rotary engine. Suitable internal combustion engines include marine diesel engines (such as inland marine), aviation piston engines, light duty diesel engines, as well as motorcycle, automobile, locomotive, and truck engines.

[0020] The internal combustion engine may include one or more components of aluminum alloys, lead, tin, copper, cast iron, magnesium, ceramics, stainless steel, composites, and / or mixtures thereof. The components may be coated, for example, with diamond-like carbon coatings, lubricating coatings, phosphorus-containing coatings, molybdenum-containing coatings, graphite coatings, nanoparticle-containing coatings, and / or mixtures thereof. The aluminum alloy may include aluminum silicate, aluminum oxide, or other ceramic materials. In one embodiment, the aluminum alloy is an aluminum silicate surface. As used herein, the term "aluminum alloy" is synonymous with "aluminum composite" and is intended to describe a component or surface that includes aluminum and another component that mixes or reacts at a microscopic or near-microscopic level, regardless of its detailed structure. This includes conventional alloys with metals other than aluminum, as well as composite or alloy-like structures with non-metallic elements or compounds, such as ceramic-like materials.

[0021] The lubricating oil composition for internal combustion engines may be suitable for any engine lubricant, regardless of sulfur, phosphorus, or sulfated ash (ASTM D-874) content. The sulfur content of the engine oil lubricant may be about 1 wt.% or less, or about 0.8 wt.% or less, or about 0.5 wt.% or less, or about 0.3 wt.% or less, or about 0.2 wt.% or less. In one embodiment, the sulfur content may range from about 0.001 wt.% to about 0.5 wt.%, or about 0.01 wt.% to about 0.3 wt.%. The phosphorus content may be about 0.2 wt.% or less, or about 0.1 wt.% or less, or about 0.085 wt.% or less, or about 0.08 wt.% or less, or even about 0.06 wt.% or less, about 0.055 wt.% or less, or about 0.05 wt.% or less. In one embodiment, the phosphorus content may be about 50 ppm to about 1000 ppm, or about 325 ppm to about 850 ppm. The total sulfated ash content may be about 2% by weight or less, or about 1.5% by weight or less, or about 1.1% by weight or less, or about 1% by weight or less, or about 0.8% by weight or less, or about 0.5% by weight or less. In one embodiment, the sulfated ash content may be about 0.05% by weight to about 0.9% by weight, or 0.1% by weight or about 0.2% by weight to about 0.45% by weight. In another embodiment, the sulfur content may be about 0.4% by weight or less, the phosphorus content may be about 0.08% by weight or less, and the sulfated ash is about 1% by weight or less. In yet another embodiment, the sulfur content may be about 0.3% by weight or less, the phosphorus content may be about 0.05% by weight or less, and the sulfated ash is about 0.8% by weight or less.

[0022] In one embodiment, the lubricating oil composition is an engine oil, and the lubricating oil composition may have (i) a sulfur content of less than or equal to about 0.5 wt.%, (ii) a phosphorus content of less than or equal to about 0.1 wt.%, and (iii) a sulfated ash content of less than or equal to about 1.5 wt.%.

[0023] In one embodiment, the lubricating oil composition is suitable for a two-stroke or four-stroke marine diesel internal combustion engine. In one embodiment, the marine diesel combustion engine is a two-stroke engine. In some embodiments, the lubricating oil composition is not suitable for a two-stroke or four-stroke marine diesel internal combustion engine for one or more reasons including, but not limited to, the high sulfur content of the fuels used to power the marine engines and the high TBN required for engine oils suitable for marine use (e.g., greater than about 40 TBN for engine oils suitable for marine use).

[0024] In some embodiments, the lubricating oil compositions are suitable for use in engines powered by low sulfur fuels, such as fuels containing about 1 to about 5% sulfur. Highway vehicle fuels contain about 15 ppm sulfur (or about 0.0015% sulfur).

[0025] Low speed diesel typically refers to marine engines, medium speed diesel typically refers to locomotives, and high speed diesel typically refers to highway vehicles. The lubricating oil composition may be suitable for only one or all of these types.

[0026] Additionally, the lubricants herein may meet one or more industry specification requirements, such as ILSAC GF-3, GF-4, GF-5, GF-5+, GF-6, PC-11, CF, CF-4, CH-4, CK-4, FA-4, CJ-4, CI-4 Plus, CI-4, API SG, SJ, SL, SM, SN, SN PLUS, ACEA A1 / B1, A2 / B2, A3 / B3, A3 / B4, A5 / B5, A7 / B7, C1, C2, C3, C4, C5, C6, E4 / E6 / E7 / E9, Euro5 / 6, JASO DL-1, Low SAPS, Mid SAPS, or Dexos1™, Dexos2™, MB-Approval™, Dexos3™, Dexos4™, Dexos5™, Dexos6™, Dexos7™, Dexos8™, Dexos9™, Dexos11™, Dexos12™, Dexos13™, Dexos14™, Dexos15™, Dexos16™, Dexos17™, Dexos18™, Dexos19™, Dexos21™, Dexos22™, Dexos23™, Dexos24™, Dexos25™, Dexos26™, Dexos27™, Dexos28™, Dexos29™, Dexos29™, Dexos29™, Dexos29™, Dexos29™, Dexos30™, Dexos30™, Dexos31™, Dexos32™, Dexos33™, Dexos34™, Dexos35™, Dexos36™, Dexos37™, Dexos38™, Dexos39™, Dexos39™, Dexos39™, Dexos3 229.1, 229.3, 229.5, 22.51 / 229.31, 229.52, 229.6, 229.71, 226.5, 226.51, 228.0 / .1, 228.2 / .3, 228.31, 228.5, 228.51, 228.61, VW 501.01,502.00,503.00 / 503.01,504.00,505.00,505.01,506.00 / 506.01,507.00,508.00,509.00,508.88,509.99,BMW Longlife-01, Longlife-01FE, Longlife-04, Longlife-12FE, Longlife-14FE+, Longlife-17FE+, Porsche A40, C30, Peugeot Citroen Automobiles B71 2290, B71 2294, B71 2295, B71 2296, B71 2297, B71 2300, B71 2302, B71 2312, B71 2007, B71 2008, Renault RN0700, RN0710, RN0720, Ford WSS-M2C153-H, WSS-M2C930-A, WSS-M2C945-A, WSS-M2C913A, WSS-M2C913-B, WSS-M2C913-C, WSS-M2C913-D, WSS-M2C948-B, WSS-M2C948-A, GM 6094-M, Chrysler MS-6395, Fiat 9.55535 G1, G2, M2, N1, N2, Z2, S1, S2, S3, S4, T2, DS1, DSX, GH2, GS1, GSX, CR1, Jaguar Land Rover STJLR.03.5003, STJLR.03.The compositions may be suitable to meet original equipment manufacturer specifications such as STJLR.03.5004, STJLR.03.5005, STJLR.03.5006, STJLR.03.5007, STJLR.51.5122, or any past or future PCMO or HDD specifications not listed herein. In some embodiments for passenger car motor oil (PCMO) applications, the amount of phosphorus in the final fluid is 1000 ppm or less, or 900 ppm or less, or 800 ppm or less.

[0027] Other hardware may not be suitable for use with the disclosed lubricants. "Functional fluid" is a term that encompasses a variety of fluids, including but not limited to tractor hydraulic fluids, power transmission fluids including automatic transmission fluids, continuously variable transmission fluids and manual transmission fluids, hydraulic fluids including tractor hydraulic fluids, some gear oils, power steering fluids, wind turbines, fluids used in compressors, some industrial fluids, and fluids associated with power transmission components. It should be noted that within each of these fluids, such as automatic transmission fluids, there are a variety of different types of fluids for different transmissions with different designs that require fluids with significantly different functional properties. This is in contrast to the term "lubricating fluids" that are not used to generate or transmit power.

[0028] For example, with respect to tractor hydraulic fluids, these fluids are general purpose products used for all lubrication applications in the tractor except for lubricating the engine, which may include lubricating the gearbox, power take-offs and clutches, rear axles, reduction gears, wet brakes, and hydraulic accessories.

[0029] When the functional fluid is an automatic transmission fluid, the automatic transmission fluid must have enough friction for the clutch plates to transmit power. However, the coefficient of friction of the fluid tends to decrease due to the effects of temperature as the fluid heats up during operation. It is important that the tractor working fluid or automatic transmission fluid maintain a high coefficient of friction at high temperatures or else the brake system or automatic transmission may fail. This is not the function of engine oil.

[0030] Tractor fluids, such as Super Tractor Universal Oil (STUO) or Universal Tractor Transmission Oil (UTTO), may combine engine oil performance with transmission, differential, final drive planetary gear, wet brake, and hydraulic performance. Many of the additives used to formulate UTTO or STUO fluids are functionally similar but can have detrimental effects if not properly incorporated. For example, some anti-wear and extreme pressure additives used in engine oils can be highly corrosive to copper components in hydraulic pumps. Detergents and dispersants used in gasoline or diesel engine performance can be detrimental to wet brake performance. Friction modifiers specific to quiet wet brake squeal may lack the thermal stability required for engine oil performance. Each of these fluids is designed to meet specific stringent manufacturer requirements, whether functional, tractor, or lubricity.

[0031] The present disclosure provides novel lubricating oil blends formulated for use as automotive crankcase lubricants. The present disclosure provides novel lubricating oil blends formulated for use as 2T and / or 4T motorcycle crankcase lubricants. Embodiments of the present disclosure may provide lubricating oils suitable for crankcase applications and having improvements in air entrainment, alcohol fuel compatibility, antioxidant properties, antiwear performance, biofuel compatibility, foam reduction properties, friction reduction, fuel economy, pre-ignition prevention, rust prevention, sludge and / or soot dispersancy, piston cleanliness, deposit formation, and water resistance properties.

[0032] The engine oils of the present disclosure may be formulated by adding one or more additives to a suitable base oil formulation, as described in detail below. The additives may be combined with the base oil in the form of an additive package (or concentrate), or alternatively, may be combined individually with the base oil (or a mixture of both). The fully formulated engine oil may exhibit improved performance characteristics based on the additives added and their respective proportions.

[0033] Further details and advantages of the present disclosure will be set forth in part in the description which follows and / or may be learned by the practice of the present disclosure. The details and advantages of the present disclosure may be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure as claimed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] The present disclosure relates to lubricating oil compositions having improved resistance to sludge deposits and varnish formation in engines or other machine parts lubricated with the lubricating oil. The lubricating oils of the present disclosure are useful as passenger vehicle engine oil (PVEO) products, commercial vehicle engine oil (CVEO) products, or other applications in which the lubricating oil is subjected to thermal and oxidative conditions.

[0035] In one embodiment, the lubricating oil composition comprises greater than 50 weight percent of a base oil of lubricating viscosity and an additive composition, the additive composition comprising an amount of one or more zinc dialkyldithiophosphates (ZDDP compounds) and an amount of one or more viscosity modifiers, wherein the amount of phosphorus (P) in weight percent provided to the lubricating oil composition by the one or more ZDDP compounds divided by the amount of the one or more viscosity modifiers (VM) in weight percent based on the total weight of the lubricating oil composition is a P / VM quotient of greater than about 0.0075.

[0036] ZDDP has antioxidant and antiwear functions. Without being bound by theory, it is believed that ZDDP acts as an oxidation inhibitor to minimize the formation of deposit and varnish precursors such as hydroperoxides and radicals. These species are reactive and attack the hydrocarbon base oil and additives that make up the lubricant, forming sludge, resins, varnish, and hard deposits. Viscosity modifiers work in concert with ZDDP to improve low temperature rheology and thickening efficiency. This not only results in improved deposit and varnish control, but also minimizes the abrasive wear and viscosity increase associated with fine particles.

[0037] Base oil The base oil used in the lubricating oil compositions herein may be selected from any of the base oils in Groups I to V as specified in the American Petroleum Institute (API) Base Oil Interchangeability Guidelines. The five base oil groups are:

[0038] [Table 1]

[0039] Group I, Group II, and Group III are mineral oil process feedstocks. Group IV base oils contain true synthetic molecular species produced by polymerization of olefinically unsaturated hydrocarbons. Many Group V base oils are also true synthetic products and may include diesters, polyol esters, polyalkylene glycols, alkylated aromatics, polyphosphate esters, polyvinyl ethers, and / or polyphenyl ethers, etc., but may also be natural oils, such as vegetable oils. It should be noted that Group III base oils are derived from mineral oils, but the rigorous processing these fluids undergo makes their physical properties very similar to some true synthetic oils, such as PAOs. Thus, oils derived from Group III base oils may be referred to as synthetic fluids in the industry. Group II+ may include high viscosity index Group II.

[0040] The base oil used in the disclosed lubricating oil compositions can be mineral oils, animal oils, vegetable oils, synthetic oils, synthetic oil blends, or mixtures thereof. Suitable oils can be derived from hydrocracked, hydrogenated, hydrofinished, unrefined, refined, and rerefined oils, and mixtures thereof.

[0041] Unrefined oils are derived from natural, mineral, or synthetic sources with little or no further purification treatment. Refined oils are similar to unrefined oils, except that they have been treated with one or more purification steps that may result in the improvement of one or more properties. Examples of suitable purification techniques are solvent extraction, secondary distillation, acid or base extraction, filtration, percolation, etc. Oils refined to edible quality may or may not be useful. Edible oils may also be called white oils. In some embodiments, the lubricating oil composition does not include edible oils or white oils.

[0042] Rerefined oils are also known as reclaimed or reprocessed oils. These oils are obtained similarly to refined oils using the same or similar processes. Often these oils are further processed by techniques directed to the removal of spent additives and oil breakdown products.

[0043] Mineral oils may include oils obtained by drilling or from plants and animals, or any mixture thereof. For example, such oils may include, but are not limited to, castor oil, lard oil, olive oil, peanut oil, corn oil, soybean oil, and linseed oil, as well as mineral lubricating oils, such as liquid petroleum oils, and solvent- or acid-treated mineral lubricating oils of the paraffinic, naphthenic, or mixed paraffinic-naphthenic types. Such oils may be partially or fully hydrogenated, if desired. Oils derived from coal or shale may also be useful.

[0044] Useful synthetic lubricating oils may include hydrocarbon oils such as polymerized, oligomerized, or interpolymerized olefins (e.g., polybutylene, polypropylene, propylene isobutylene copolymers); poly(1-hexene), poly(1-octene), trimers or oligomers of 1-decene, such as poly(1-decene) (such materials are often referred to as alpha-olefins), and mixtures thereof; alkyl-benzenes (e.g., dodecylbenzene, tetradecylbenzene, dinonylbenzene, di-(2-ethylhexyl)-benzene); polyphenyls (e.g., biphenyl, terphenyl, alkylated polyphenyls); diphenylalkanes, alkylated diphenylalkanes, alkylated diphenyl ethers, and alkylated diphenyl sulfides, and derivatives, analogs, and homologs thereof, or mixtures thereof. The polyalphaolefins are typically hydrogenated materials.

[0045] Other synthetic lubricating oils include polyol esters, diesters, liquid esters of phosphorus-containing acids (e.g., tricresyl phosphate, trioctyl phosphate, and diethyl ester of decane phosphonic acid), or polymeric tetrahydrofurans. Synthetic oils may be produced by the Fischer-Tropsch reaction and typically may be hydroisomerized Fischer-Tropsch hydrocarbons or waxes. In one embodiment, the oils may be prepared by the Fischer-Tropsch gas-liquid synthesis procedure, as well as other gas-liquid oils.

[0046] A major amount of base oil included in the lubricating composition may be selected from the group consisting of Group I, Group II, Group III, Group IV, Group V, and combinations of two or more of the foregoing, but the major amount of base oil is other than the base oil resulting from the provision of an additive component or viscosity index improver in the composition. In another embodiment, a major amount of base oil included in the lubricating composition may be selected from the group consisting of Group II, Group III, Group IV, Group V, and combinations of two or more of the foregoing, but the major amount of base oil is other than the base oil resulting from the provision of an additive component or viscosity index improver in the composition.

[0047] The amount of oil of lubricating viscosity present may be the remainder remaining after subtracting the sum of the amounts of performance additives, including viscosity index improvers and / or pour point depressants and / or other top treatment additives, from 100% by weight. For example, the oil of lubricating viscosity may be present in the final fluid in a major amount, such as greater than about 50% by weight, greater than about 60% by weight, greater than about 70% by weight, greater than about 80% by weight, greater than about 85% by weight, or greater than about 90% by weight.

[0048] Zinc dialkyldithiophosphate compounds The lubricating oil composition of the present disclosure for use in an internal combustion engine to improve resistance to sludge deposits and varnish formation contains an amount of one or more zinc dialkyldithiophosphates (ZDDP compounds). The one or more ZDDP compounds can also help improve the friction and wear properties of the lubricating oil composition.

[0049] The one or more ZDDP compounds may be present in the lubricating oil composition in an amount of from about 0.01% to about 15% by weight, or from about 0.01% to about 10% by weight, or from about 0.05% to about 5% by weight, or from about 0.1% to about 3% by weight, based on the total weight of the lubricating oil composition.

[0050] The one or more ZDDP compounds may include ZDDPs derived from primary alkyl alcohols, secondary alkyl alcohols, or a combination of primary and secondary alkyl alcohols. The primary and secondary alkyl alcohols used to prepare the one or more ZDDP compounds may have alkyl groups containing 1 to 20 carbon atoms, or about 1 to 18 carbon atoms, or about 1 to about 16 carbon atoms, or 2 to 12 carbon atoms, or about 3 to about 8 carbon atoms. Preferably, the primary alkyl alcohol has a branch at the beta carbon relative to the hydroxyl group.

[0051] For example, an alcohol having a branch at the beta (β) carbon will have the branch at the second carbon counting from the oxygen atom of the hydroxyl group.

[0052] [ka]

[0053] Suitable examples of primary and secondary alkyl alcohols for use in preparing one or more ZDDP compounds may be selected from n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, 2-butanol, isobutyl alcohol, n-pentyl alcohol, amyl alcohol, hexanol, methyl isobutyl carbinol, isohexanol, n-heptanol, isoheptanol, octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, hexadecanol, heptadecanol, octadecanol, nonadecanol, eicosanol, and 2-ethylhexanol.

[0054] In some embodiments, the additive composition may include at least two different zinc dialkyldithiophosphate compounds. The two alkyl groups on the zinc dialkyldithiophosphate compounds may be the same or different.

[0055] In some embodiments, one or more ZDDP compounds may be present in the lubricating oil in an amount sufficient to provide from about 100 to about 1500 ppmw phosphorus, or from about 200 to about 1300 ppmw phosphorus, or from about 300 to about 1200 ppmw phosphorus, or from about 550 to about 1200 ppmw phosphorus, based on the total weight of the lubricating oil composition.

[0056] In some embodiments, at least one ZDDP compound may be present in the lubricating oil in an amount sufficient to provide from about 10 ppmw zinc to about 1500 ppmw zinc, or from about 100 ppmw zinc to about 1300 ppmw zinc, or from about 600 ppmw zinc to about 1200 ppmw zinc, based on the total weight of the lubricating oil composition.

[0057] In some embodiments, 100 mole percent of the alkyl groups of one or more of the ZDDP compounds may be derived from one or more primary alcohol groups. In some embodiments, 100 mole percent of the alkyl groups of one or more of the ZDDP compounds may be derived from one or more secondary alcohol groups. In some embodiments, a mixture of one or more all primary alcohol ZDDP compounds and one or more all secondary alcohol ZDDP compounds is provided. In some embodiments, the mixture includes one or more all primary alcohol ZDDP compounds that contribute 15 to 500 ppmw zinc to the lubricating oil composition and one or more all secondary alcohol ZDDP compounds that contribute 100 to 1000 ppm zinc, based on the weight of the lubricating oil composition, or the mixture includes one or more all primary alcohol ZDDP compounds that contribute 100 to 400 ppmw zinc to the lubricating oil composition and one or more all secondary alcohol ZDDP compounds that contribute 200 to 800 ppm zinc, based on the weight of the lubricating oil composition. In some embodiments, the mixture comprises one or more total primary alcohol ZDDP compounds contributing 10-450 ppmw phosphorus to the lubricating oil composition, and one or more total secondary alcohol ZDDP compounds contributing 100-1000 ppm phosphorus, based on the weight of the lubricating oil composition, or the mixture comprises one or more total primary alcohol ZDDP compounds contributing 100-375 ppmw phosphorus to the lubricating oil composition, and one or more total secondary alcohol ZDDP compounds contributing 300-800 ppm phosphorus, based on the weight of the lubricating oil composition.

[0058] In some embodiments, the one or more ZDDP compounds are formed with a mixture of primary and secondary alcohols. The molar ratio of primary alkyl alcohol to secondary alkyl alcohol used to make the one or more ZDDP compounds in the lubricating oil composition can be about 100:0 to 0:100, or about 100:0 to 50:50, or about 100:0 to 60:40. The one or more ZDDP compounds can have a P:Zn molar ratio of about 1.08 to 1.3, or about 1.08 to 1.2, or about 1.09 to about 1.15. In some embodiments, the one or more ZDDP compounds formed with a mixture of primary and secondary alcohols contribute 50 to 1500 ppmw of zinc based on the weight of the lubricating oil composition, or the one or more ZDDP compounds formed with a mixture of primary and secondary alcohols contribute 400 to 1300 ppmw of zinc based on the weight of the lubricating oil composition. In some embodiments, the one or more ZDDP compounds formed with a mixture of primary and secondary alcohols contribute from 40 to 1400 ppm of phosphorus to the lubricating oil composition based on the weight of the lubricating oil composition, or the one or more ZDDP compounds formed with a mixture of primary and secondary alcohols contribute from 350 to 1200 ppm of phosphorus to the lubricating oil composition based on the weight of the lubricating oil composition.

[0059] In some embodiments, the mixture comprises one or more total secondary alcohol ZDDP compounds contributing from 100 to 750 ppmw of zinc, and the one or more ZDDP compounds formed with a mixture of primary and secondary alcohols contribute from 100 to 750 ppmw of zinc to the lubricating oil composition based on the weight of the lubricating oil composition, or the mixture comprises one or more total secondary alcohol ZDDP compounds contributing from 300 to 600 ppmw of zinc, and the one or more ZDDP compounds formed with a mixture of primary and secondary alcohols contribute from 300 to 6000 ppm of zinc to the lubricating oil composition based on the weight of the lubricating oil composition.

[0060] The alcohol suitable for preparing one or more ZDDP compounds can be a primary alkyl alcohol, a secondary alkyl alcohol, or a mixture of primary and secondary alkyl alcohols. The alcohol may contain any of the following: branched, cyclic, or straight chain.

[0061] The one or more ZDDP compounds may be an oil soluble salt of a dihydrocarbyl dithiophosphate, having the following formula:

[0062] [ka] In the formula, R5 and R6 may be the same or different alkyl groups containing 1 to 20 carbon atoms, or about 1 to 18 carbon atoms, or about 1 to about 16 carbon atoms, or 2 to 12 carbon atoms, or about 3 to about 8 carbon atoms, and including moieties such as alkyl and cycloalkyl moieties. Thus, the moieties may be, for example, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, amyl, n-hexyl, i-hexyl, 4-methyl-pentyl, n-octyl, decyl, dodecyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, 2-ethylhexyl, nonadecyl, eicosyl, 2-ethylhexyl, cyclohexyl, or methylcyclopentyl.

[0063] The average number of total carbon atoms per mole of phosphorus in a ZDDP compound may be calculated by dividing the sum of the carbon atoms in the four alkyl groups R5 and R6 provided to the ZDDP compound by the alcohol used to make the ZDDP compound by 2. For example, in a single ZDDP compound, if R5 is a C3-alkyl group and R6 is a C6 alkyl group, the total number of carbon atoms is 3+3+6+6=18. Dividing this by the 2 moles of phosphorus per mole of ZDDP gives an average total of 9 carbon atoms per mole of phosphorus.

[0064] The average total number of carbon atoms per mole of phosphorus (ATCP) for a composition containing one or more ZDDP compounds can be calculated from the alcohol used to produce the ZDDP compound according to the following formula: ATCP=2 * [(mol% of Alc1 * (number of C atoms in alc1) + (mol% of alc2 * (number of C atoms in alc2) + (mol% of alc3 * number of C atoms in alc3) +... etc. In the formula, alc1, alc2, and alc3 each represent a different alcohol used to make the ZDDP compound, and the mole percent is the mole percentage of each alcohol that was present in the reaction mixture used to make the ZDDP compound. "And so forth" indicates that if more than three alcohols are used to make the ZDDP compound, the formula can be expanded to include each alcohol present in the reaction mixture.

[0065] The average total number of carbon atoms from both R5 and R6 of the ZDDP is greater than 2 carbon atoms per mole of phosphorus, and in one embodiment in the range of greater than 4 to 40 carbon atoms, or greater than 6 to about 20 carbon atoms, and in one embodiment in the range of greater than 6 to about 16 carbon atoms, and in one embodiment in the range of about 6 to about 15 carbon atoms, and in one embodiment in the range of about 9 to about 15 carbon atoms, and in one embodiment about 12 carbon atoms per mole of phosphorus.

[0066] The zinc dialkyldithiophosphate compounds may be prepared according to known techniques by first forming a dialkyl dithiophosphoric acid (DDPA), usually by reaction of one or more alcohols, and then neutralizing the formed DDPA with a zinc compound. Any basic or neutral zinc compound may be used to make the subcompound, although oxides, hydroxides, and carbonates are most commonly used. The zinc dialkyldithiophosphates of component (i) may be made by processes such as those generally described in U.S. Pat. No. 7,368,596.

[0067] The use of one or more ZDDP compounds derived from a molar ratio of primary alkyl alcohol to secondary alkyl alcohol of about 100:0 to about 0:100 unexpectedly provides increased viscosity control across a wide variety of ZDDP compounds as compared to the same lubricating oil composition, except that it does not contain a ZDDP compound. Specifically, the use of one or more ZDDP compounds derived from 100 mole percent of one or more secondary alkyl alcohols, and / or one or more ZDDP compounds derived from 100 mole percent of one or more primary alkyl alcohols to improve viscosity control unexpectedly provided increased viscosity control.

[0068] Additionally, the use of one or more ZDDP compounds derived from all secondary alkyl alcohols to one or more ZDDP compounds derived from all primary alkyl alcohols in a molar ratio ranging from 100:0 to 0.2:1, or 10:1 to 0.4:1, or 6:1 to 0.75:1 provides improved friction and / or wear results and / or viscosity control across a wide variety of ZDDP compounds compared to lubricating oil compositions other than those lacking the ZDDP compound.

[0069] The present invention may include overbased ZDDPs, which are basic ZDDPs.The term basic ZDDPs, or equivalent expressions, is used herein to describe zinc salts in which the metal substituent is present in a stoichiometrically greater amount than the phosphate radical.For example, normal or neutral zinc phosphorodithioates have two equivalents (i.e., one mole) of zinc per two equivalents (i.e., two moles) of phosphorodithioic acid, while basic zinc diorganophosphorodithioates have more than two equivalents of zinc per two equivalents of phosphorodithioic acid.

[0070] For example, overbasing can be carried out using a basic zinc compound such as zinc oxide. The amount of basic base compound required to give the desired overbasing is not critical. The essential factor is that sufficient zinc compound is present in the reaction mixture for the overbasing reaction. Although not absolutely essential, it has been found that the reaction proceeds in a more satisfactory manner when a slight excess of zinc compound is used over the amount required for the reaction. This excess should be kept to a minimum level relative to the need to remove large amounts of solids from the final product. As a general statement, the excess of zinc compound should not exceed 10-15% by weight.

[0071] Viscosity modifier The lubricating oil compositions of the present disclosure include one or more viscosity modifiers (also known as viscosity index improvers and viscosity modifiers). Viscosity modifiers provide lubricants with high and low temperature operability. These additives impart shear stability at high temperatures and acceptable viscosity at low temperatures. Viscosity modifiers work in concert with ZDDP to improve low temperature rheology and thickening efficiency. This not only results in improved deposit and varnish control, but also minimizes particulate-related abrasive wear and viscosity increase.

[0072] The viscosity modifier may be one or more dispersant viscosity modifiers that function as both viscosity modifiers and dispersants. Preferably, the lubricating oil composition contains one or more non-dispersant viscosity modifiers.

[0073] The one or more non-dispersant viscosity modifiers may be a hydrocarbon polymer which may be a polyolefin having a backbone consisting essentially of aliphatic olefins, particularly alpha olefin monomers. Thus, polyolefin in this embodiment excludes polymers having a large component of other types of monomers copolymerized in the main polymer, such as ester monomers, acid monomers, and the like. Polyolefins may contain impurity amounts of such materials, e.g., less than 5% by weight, more often less than 1% by weight, and preferably less than 0.1% by weight, of other monomers. Useful polymers include ethylene and C3-C4 28 Included are oil soluble or dispersible copolymers of alpha-olefins, or ethylene and C3-C8 alpha-olefins, or ethylene and C3-C6 alpha-olefins, or ethylene and C3-C4 alpha-olefins.

[0074] Olefin copolymers (sometimes referred to as polyolefins) may be random copolymers, block copolymers, and random block copolymers. Ethylene propylene copolymers are usually random or statistical copolymers. Random or statistical copolymers may be a mixture of two or more polymers made in two or more reactors in series. Block copolymers may be obtained by carrying out the reaction in a tubular reactor. Such a procedure is described in U.S. Pat. No. 4,804,794, which is incorporated herein by reference for its relevant disclosure in this regard. These polymers are commercially available as PARATONE® 8941 and PARATONE® 8910 (sold by Chevron Oronite Company LLC). Block copolymers may also be obtained by selecting an appropriate catalyst and / or process for polymerization. Such polymers are described in U.S. Pre-Grant Publication No. 2006 / 0199896, which is incorporated herein by reference for its relevant disclosure in this regard. Such olefin block copolymers are commercially available from Dow Chemical under the trade name INFUSE™ olefin block copolymers.

[0075] Numerous U.S. patents describe the preparation of copolymers of alpha olefins, including: Copolymers of ethylene and higher alpha olefins are the most common copolymers of aliphatic olefins. Ethylene-propylene copolymers are the most common ethylene-alpha-olefin copolymers and are preferred for use in the present invention. A description of ethylene-propylene copolymers can be found in U.S. Pat. No. 4,137,185, which is incorporated herein by reference. Useful ethylene-alpha olefins, typically ethylene-propylene copolymers, are commercially available. Ethylene-alpha olefin copolymers containing about 30 to about 60 weight percent of monomer units derived from ethylene are commonly referred to as low ethylene or amorphous copolymers. Ethylene alpha-olefin copolymers containing about 60 to about 80 weight percent of units derived from ethylene are commonly referred to as high ethylene (semicrystalline) polymers. In one embodiment, the one or more non-dispersant viscosity modifiers are ethylene-propylene copolymers having about 40 to about 60 weight percent ethylene and about 60 to about 40 weight percent propylene, the weight percent being based on the total weight of the olefin polymer. In another embodiment, the olefin polymer is an ethylene-propylene copolymer having about 45 to about 55 weight percent ethylene and about 55 to about 45 weight percent propylene, the weight percent being based on the total weight of the olefin polymer. In another embodiment, the olefin polymer is an ethylene-propylene copolymer having a weight percent of ethylene greater than the weight percent of propylene, the weight percent being based on the total weight of the olefin polymer. The polymer substrate (i.e., the portion of the olefin polymer that is the backbone without the substituents) can also contain a mixture of amorphous and semi-crystalline polymers in weight ratios as described in U.S. Pat. No. 5,427,702, incorporated herein by reference.Exemplary commercially available polymers including amorphous copolymers are PARATONE® 8921 available from Chevron Oronite, LZ7067, LZ7065, and LZ7060 available from Lubrizol Corporation, Keltan® 1200A, 1200B available from Lanxess, and NDR125 available from Dow Chemical Company.

[0076] Olefin polymers (sometimes referred to as polyolefins) having a backbone consisting essentially of aliphatic olefins may be polymers containing dienes. The olefin polymers may be homopolymers or copolymers of one or more dienes. The dienes may be conjugated, such as isoprene, butadiene, 2,3-dimethyl-1,3-butadiene, chloroprene, 1,3-butadiene, and piperylene, or non-conjugated, such as 1-4 hexadiene, ethylidene norbornene, vinyl norbornene, 4-vinyl cyclohexene, and dicyclopentadiene. Polymers of conjugated dienes are preferred. In one embodiment, the total carbon content of the diene may not exceed 20 carbons. Such polymers are conveniently prepared via free radical and anionic polymerization techniques. Emulsion techniques are commonly used for free radical polymerization.

[0077] The olefin polymer having a backbone consisting essentially of aliphatic olefins may be a copolymer of a conjugated diene and a vinyl-substituted aromatic compound. In one embodiment, the olefin polymer is a copolymer of a vinyl-substituted aromatic compound and a conjugated diene. The vinyl-substituted aromatic generally contains from 8 to about 20 carbon atoms, preferably from 8 to 12 carbon atoms, and most preferably 8 or 9 carbon atoms. Examples of vinyl-substituted aromatic compounds include vinyl anthracene, vinyl naphthalene, and vinyl benzene (styrene-based compounds). Styrenic compounds are preferred, examples of which are styrene, alpha-methylstyrene, ortho-methylstyrene, meta-methylstyrene, para-methylstyrene, para-tertiary-butylstyrene, and chlorostyrene, with styrene being preferred. The vinyl-substituted aromatic content of these copolymers is typically in the range of about 15% to about 70% by weight, or about 20% to about 40% by weight, based on the total weight of the copolymer. The aliphatic conjugated diene content of these copolymers typically ranges from about 30% to about 85% by weight, or from about 60% to about 80% by weight, based on the total weight of the copolymer.

[0078] The polymers, particularly styrene-diene copolymers, can be random or block copolymers, including regular or random block copolymers. Random copolymers are copolymers in which the comonomers are randomly or nearly randomly arranged in the polymer chain, and the homopolymers of either monomer are not significantly blocked. Regular block copolymers are copolymers in which a small number of relatively long chains of homopolymers of one type of monomer are alternately bonded to a small number of relatively long chains of homopolymers of another type of monomer. Random block copolymers are copolymers in which a large number of relatively short segments of homopolymers of one type of monomer alternate with relatively short segments of homopolymers of another monomer. Block copolymers, particularly diblock copolymers, are preferred. Examples of such polymer substrates are illustrated in U.S. Pat. Nos. 6,162,768, 6,215,033, 6,248,702, and 6,034,184, which are incorporated herein by reference.

[0079] The random, regular block and random block polymers used in the present invention may be linear, or they may be partially or highly branched. The relative arrangement of the homopolymer segments in the linear regular block or random block polymer is obvious. The difference in structure is in the number and relative size of the homopolymer segments, the arrangement in either type of linear block polymer always alternates in the homopolymer segments.

[0080] Normal or regular block copolymers usually have from 1 to about 5, often from 1 to about 3, and preferably only 1 to about 2 relatively large homopolymer blocks of each monomer. The size of the blocks is not necessarily the same and may vary considerably. The only stipulation is that any regular block copolymer contains relatively few but relatively large alternating homopolymer segments.

[0081] These olefin polymers having a backbone consisting essentially of aliphatic olefins can be hydrogenated to reduce the amount of olefinic unsaturation present in the polymer. They may or may not be fully hydrogenated. Hydrogenation is often accomplished using catalytic methods. Catalytic techniques using hydrogen under high pressure and temperature are well known to those skilled in the chemical arts. Other methods are also useful and well known to those skilled in the art. An extensive discussion of diene polymers can be found in "Encyclopedia of Polymer Science and Engineering", Volume 2, pp. 550-586 and Volume 8, pp. 499-532, Wiley-Interscience (1986), which are expressly incorporated herein by reference for their relevant disclosure in this regard. As a specific example, U.S. Pat. No. 3,959,161 teaches the preparation of hydrogenated polybutadiene. In another example, 1,4-polyisoprene, upon hydrogenation, becomes an alternating copolymer of ethylene and propylene. Copolymers of conjugated dienes are prepared from two or more conjugated dienes. Useful dienes are the same as those described above in the preparation of homopolymers of conjugated dienes. For example, U.S. Patent No. 4,073,737 describes the preparation and hydrogenation of butadiene-isoprene copolymers.

[0082] The olefin copolymers may have a weight average molecular weight (Mw) as determined by gel permeation chromatography using polystyrene standards ranging from about 7,000 g / mol to about 500,000 g / mol, or from about 20,000 g / mol to about 400,000 g / mol, or from about 100,000 g / mol to about 300,000 g / mol. The olefin copolymers may have a number average molecular weight (Mn) as determined by gel permeation chromatography using polystyrene standards ranging from about 2,000 g / mol to about 400,000 g / mol, or from about 20,000 g / mol to about 200,000 g / mol, or from about 50,000 g / mol to about 150,000 g / mol. Exemplary polydispersity values ​​(Mw / Mn) range from about 1.1 to about 10, or from about 1.2 to about 3.0, or from about 1.3 to about 3.0, or from about 1.3 to about 2.2.

[0083] Suitable viscosity modifiers may include high molecular weight polyesters or functionalized polyolefins, such as ethylene-propylene copolymers functionalized with the reaction product of an acylating agent (such as maleic anhydride) with an amine, amine-functionalized polymethacrylates, or esterified maleic anhydride-styrene copolymers reacted with amines.Typical molecular weights (Mw) of these polymers are from 10,000 g / mol to 1,500,000 g / mol, more typically from 20,000 g / mol to 1,200,000 g / mol, and even more typically from 50,000 g / mol to 1,000,000 g / mol, as determined by gel permeation chromatography using polystyrene standards.

[0084] Examples of suitable viscosity modifiers include linear or star polymers and copolymers of methacrylates, such as copolymers of various chain length alkyl methacrylates.

[0085] Suitable non-dispersant olefin copolymer viscosity modifiers are non-polar hydrogenated olefin copolymer type viscosity modifiers, such as the LUBRIZOL 7075™ series manufactured by LUBRIZOL (Wickliffe, Ohio). Hydrogenated olefin copolymers are the most widely used type of viscosity modifier for passenger car motor oils and heavy duty diesel engine oils. Olefin copolymers are commercially available from Chevron Oronite Company LLC under the trade name "PARATONE®" (such as "PARATONE® 8921" and "PARATONE® 8941"), from Afton Chemical Corporation under the trade name "HiTEC®" (such as "HiTEC® 5754A"), and from The Lubrizol Corporation under the trade name "Lubrizol® 7067C". Polyisoprene polymers are commercially available from Infineum International Limited, for example under the trade name "SV200". Diene-styrene copolymers are commercially available from Infineum International Limited, for example under the trade name "SV 260".

[0086] The shear stability index (SSI) of the polymer substrate (i.e., the portion of the olefin polymer that is the backbone without any substituents) typically ranges from about 3 to about 60, or from about 5 to about 50, or from about 15 to about 40, or from about 20 to about 30. SSI is measured using test method ASTM-D6278 for evaluating the shear stability of polymer-containing fluids. The test method measures the percent viscosity loss at 100° C. of the polymer-containing fluid as evaluated by the diesel injector rig procedure using the European diesel injector test facility. The viscosity loss reflects the polymer degradation due to shear at the nozzle.

[0087] In one embodiment of the present disclosure, the viscosity modifier and / or dispersant viscosity modifier may be used in an amount greater than about 0.5 wt%, or from about 0.5 wt% to about 30 wt%, or from about 0.9 wt% to about 25 wt%, or from about 1.0 wt% to about 25 wt%, or from about 1.0 wt% to about 20 wt%, where the amount is based on the total weight of the lubricating oil composition.

[0088] For example, the amount of phosphorus (P) in weight percent provided to the lubricating oil composition by the one or more ZDDP compounds divided by the amount of one or more viscosity modifiers (VM) in weight percent based on the total weight of the lubricating oil composition is a P / VM quotient of greater than 0.0075, or greater than about 0.77, or greater than about 0.0077 to less than 0.1, or greater than about 0.0077 and less than 0.03, or greater than about 0.0077 and less than 0.02. For example, the P / VM quotient can be greater than about 0.0075 and the amount of VM is less than 0.14 wt%, or the P / VM quotient is greater than about 0.0077 and the amount of VM is less than 13 wt%, or the P / VM quotient is greater than about 0.007 and less than 0.03 and the amount of VM is less than 12 wt%.

[0089] Antioxidants The lubricating oil composition herein may also optionally contain one or more antioxidants. Antioxidant compounds are known and include, for example, phenates, phenate sulfides, sulfurized olefins, phosphosulfurized terpenes, sulfurized esters, aromatic amines, alkylated diphenylamines (e.g., nonyldiphenylamine, di-nonyldiphenylamine, octyldiphenylamine, di-octyldiphenylamine), phenyl-alpha-naphthylamines, alkylated phenyl-alpha-naphthylamines, hindered non-aromatic amines, phenols, hindered phenols, oil-soluble molybdenum compounds, polymeric antioxidants, or mixtures thereof. The antioxidant compounds may be used alone or in combination.

[0090] The hindered phenol antioxidant may contain secondary butyl and / or tertiary butyl groups as steric hindrance groups. The phenol group may be further substituted with a hydrocarbyl group and / or a bridging group that connects to a second aromatic group. Examples of suitable hindered phenol antioxidants include 2,6-di-tert-butylphenol, 4-methyl-2,6-di-tert-butylphenol, 4-ethyl-2,6-di-tert-butylphenol, 4-propyl-2,6-di-tert-butylphenol or 4-butyl-2,6-di-tert-butylphenol, or 4-dodecyl-2,6-di-tert-butylphenol. In one embodiment, the hindered phenol antioxidant may be an ester, but may include, for example, Irganox™ L-135 available from BASF or an addition product derived from 2,6-di-tert-butylphenol and an alkyl acrylate. Additionally, the alkyl group may contain from about 1 to about 18, or from about 2 to about 12, or from about 2 to about 8, or from about 2 to about 6, or about 4 carbon atoms. Another commercially available hindered phenol antioxidant, which may be an ester, may include Ethanox™ 4716 available from Albemarle Corporation.

[0091] Useful antioxidants may include diarylamines and high molecular weight phenols. In one embodiment, the lubricating oil composition may contain a mixture of diarylamines and high molecular weight phenols, such that each antioxidant may be present in an amount sufficient to provide up to about 5 wt. %, based on the final weight of the lubricating oil composition. In one embodiment, the antioxidant may be a mixture of about 0.3 to about 1.5 wt. % diarylamines and about 0.4 to about 2.5 wt. % high molecular weight phenols, based on the final weight of the lubricating oil composition.

[0092] Examples of suitable olefins that can be sulfurized to form sulfurized olefins include propylene, butylene, isobutylene, polyisobutylene, pentene, hexene, heptene, octene, nonene, decene, undecene, dodecene, tridecene, tetradecene, pentadecene, hexadecene, heptadecene, octadecene, nonadecene, eicosene, or mixtures thereof. In one embodiment, hexadecene, heptadecene, octadecene, nonadecene, eicosene, or mixtures thereof, as well as their dimers, trimers, and tetramers, are particularly useful olefins. Alternatively, the olefins can be Diels-Alder adducts of dienes such as 1,3-butadiene and unsaturated esters such as butyl acrylate.

[0093] Another class of sulfurized olefins includes sulfurized fatty acids and their esters. The fatty acids are often derived from vegetable or animal oils and typically contain from about 4 to about 22 carbon atoms. Examples of suitable fatty acids and their esters include triglycerides, oleic acid, linoleic acid, palmitoleic acid, or mixtures thereof. Often, the fatty acids are derived from lard oil, tall oil, peanut oil, soybean oil, cottonseed oil, sunflower seed oil, or mixtures thereof. The fatty acids and / or esters may be mixed with olefins, such as α-olefins.

[0094] In another alternative embodiment, the antioxidant composition contains a molybdenum-containing antioxidant in addition to the phenolic and / or aminic antioxidants discussed above. When a combination of these three antioxidants is used, preferably the ratio of phenolic to amine to molybdenum-containing is (0-2):(0-2):(0-1).

[0095] The one or more antioxidants may be present in the range of from about 0% to about 20%, or from about 0.1% to about 10%, or from about 0.4% to about 4% by weight of the lubricating oil composition.

[0096] Anti-wear Agent The lubricating oil composition herein may also optionally contain one or more antiwear agents in addition to one or more ZDDP compounds discussed above. Examples of suitable antiwear agents include, but are not limited to, metal thiophosphates; phosphoric acid esters or salts thereof; phosphoric acid esters; phosphites; phosphorus-containing carboxylic acid esters, ethers, or amides; sulfurized olefins; thiocarbamate-containing compounds, such as thiocarbamate esters, alkylene-linked thiocarbamates, and bis(S-alkyldithiocarbamyl) disulfides; and mixtures thereof. A suitable antiwear agent may be molybdenum dithiocarbamate. Phosphorus-containing antiwear agents are more fully described in EP 612839. Dialkyldithiophosphates with metals other than zinc, such as alkali metals, alkaline earth metals, aluminum, lead, tin, molybdenum, manganese, nickel, copper, or titanium, may be used.

[0097] Further examples of suitable antiwear agents include titanium compounds, tartrates, tartrimides, oil-soluble amine salts of phosphorus compounds, sulfurized olefins, phosphites (e.g., dibutyl phosphite), phosphonates, thiocarbamate-containing compounds, such as thiocarbamate esters, thiocarbamate amides, thiocarbamic acid ethers, alkylene-linked thiocarbamates, and bis(S-alkyldithiocarbamyl) disulfides. The tartrates or tartrimides may contain alkyl-ester groups, but the total number of carbon atoms on the alkyl group may be at least 8. The antiwear agent may, in one embodiment, include citrates.

[0098] The antiwear agent may be present in a range including from about 0% to about 15%, or from about 0.01% to about 10%, or from about 0.05% to about 5%, or from about 0.1% to about 3% by weight of the lubricating oil composition.

[0099] Boron-Containing Compounds The lubricating oil compositions herein may optionally contain one or more boron-containing compounds.

[0100] Examples of boron-containing compounds include borate esters, borated fatty amines, borated epoxides, borated detergents, and borated dispersants such as borated succinimide dispersants, as disclosed in U.S. Pat. No. 5,883,057.

[0101] When present, the boron-containing compound may be used in an amount sufficient to provide up to about 8 wt. %, from about 0.01 wt. % to about 7 wt. %, from about 0.05 wt. % to about 5 wt. %, or from about 0.1 wt. % to about 3 wt. % of the lubricating oil composition.

[0102] Detergent The lubricating oil composition may optionally further comprise one or more neutral, low-based, or overbased detergents, and mixtures thereof. Suitable detergent substrates include phenates, sulfur-containing phenates, sulfonates, calixarates, salixarates, salicylates, carboxylic acids, phosphoric acids, mono- and / or di-thiophosphoric acids, alkylphenols, sulfur-linked alkylphenol compounds, or methylene-bridged phenols. Suitable detergents and their preparation methods are described in more detail in numerous patent publications, including U.S. Pat. No. 7,732,390 and references cited therein.

[0103] The detergent substrate may be salified with an alkali or alkaline earth metal, such as, but not limited to, calcium, magnesium, potassium, sodium, lithium, barium, or mixtures thereof. In some embodiments, the detergent does not contain barium. In some embodiments, the detergent may contain trace amounts of other metals, such as magnesium or calcium, in amounts such as 50 ppm or less, 40 ppm or less, 30 ppm or less, 20 ppm or less, or 10 ppm or less. Suitable detergents may include alkali or alkaline earth metal salts of petroleum sulfonic acids and long chain mono- or di-alkylaryl sulfonic acids, where the aryl groups are benzyl, tolyl, and xylyl. Examples of suitable detergents include, but are not limited to, calcium phenate, sulfur-containing calcium phenate, calcium sulfonate, calcium calixarate, calcium salixarate, calcium salicylate, calcium carboxylate, calcium phosphate, calcium mono- and / or di-thiophosphate, calcium alkylphenol, calcium sulfur-bound alkylphenol compound, calcium methylene bridged phenol, magnesium phenate, sulfur-containing magnesium phenate, magnesium sulfonate, magnesium calixarate, magnesium salixarate, magnesium salicylate, magnesium carboxylate, magnesium phosphate, magnesium mono- and / or di-thiophosphate, magnesium alkylphenol, magnesium sulfur-bound alkylphenol compound, magnesium methylene bridged phenol, sodium phenate, sulfur-containing sodium phenate, sodium sulfonate, sodium calixarate, sodium salixarate, sodium salicylate, sodium carboxylate, sodium phosphate, sodium mono- and / or di-thiophosphate, sodium alkylphenol, sodium sulfur-bound alkylphenol compound, or sodium methylene bridged phenol.

[0104] Overbased detergent additives are well known in the art and may be alkali or alkaline earth metal overbased detergent additives. Such detergent additives may be prepared by reacting a metal oxide or metal hydroxide with a substrate and carbon dioxide gas. The substrate is typically an acid, such as an aliphatic substituted sulfonic acid, an aliphatic substituted carboxylic acid, or an aliphatic substituted phenol.

[0105] The term "overbased" refers to metal salts, such as metal salts of sulfonic acids, carboxylic acids, and phenols, in which the amount of metal present exceeds the stoichiometric amount. Such salts may have a conversion level of more than 100% (i.e., such salts may contain more than 100% of the theoretical amount of metal required to convert the acid to its "standard" or "neutral" salt). The expression "metal ratio", often abbreviated as MR, is used to indicate the ratio of the total chemical equivalents of the metal in an overbased salt to the chemical equivalents of the metal in a neutral salt, according to known chemical reactivity and stoichiometry. In standard or neutral salts, the metal ratio (MR) is 1, whereas in overbased salts, the MR is greater than 1. They are generally referred to as overbased, hyperbased, or superbased salts and may be salts of organic sulfur acids, carboxylic acids, or phenols.

[0106] The overbased detergent of the lubricating oil composition may have a total base number (TBN) of about 200 mg KOH / gram or more, or, as a further example, about 250 mg KOH / gram or more, or about 350 mg KOH / gram or more, or about 375 mg KOH / gram or more, or about 400 mg KOH / gram or more, as measured by the method of ASTM D-2896. When such detergent compositions are formed in an inert diluent, such as a process oil, usually a mineral oil, the total base number reflects the basicity of the entire composition, including the diluent and any other materials that may be included in the detergent composition (e.g., accelerators, etc.).

[0107] Examples of suitable overbased detergents include, but are not limited to, overbased calcium phenates, overbased calcium sulfur-containing phenates, overbased calcium sulfonates, overbased calcium calixarates, overbased calcium salixarates, overbased calcium salicylates, overbased calcium carboxylic acids, overbased calcium phosphates, overbased calcium mono- and / or di-thiophosphates, overbased calcium alkylphenols, overbased calcium sulfur-bound alkylphenol compounds, overbased calcium methylene bridged phenols, overbased magnesium phenates, overbased magnesium sulfur-containing phenates, overbased magnesium sulfonates, overbased magnesium calixarates, overbased magnesium salixarates, overbased magnesium salicylates, overbased magnesium carboxylic acids, overbased magnesium phosphates, overbased magnesium mono- and / or di-thiophosphates, overbased magnesium alkylphenols, overbased magnesium sulfur-bound alkylphenol compounds, or overbased magnesium methylene bridged phenols.

[0108] The overbased detergent may have a metal to substrate ratio of from 1.1:1, or from 2:1, or from 4:1, or from 5:1, or from 7:1, or from 10:1 or greater.

[0109] The one or more detergents may be low-based / neutral detergents having a TBN of up to 175 mg KOH / g, or up to 150 mg KOH / g. The low-based / neutral detergents may be formed from detergent substrates salified with an alkali metal or another alkaline earth metal, such as, but not limited to, calcium, magnesium, potassium, sodium, lithium, barium, or mixtures thereof. In some embodiments, the detergent does not contain barium. The low-based / neutral detergent may be selected from a sulfonate, phenate, or salicylate detergent. In some embodiments, the low-based / neutral detergent is a calcium-containing detergent, or a mixture of calcium-containing detergents. In some embodiments, the low-based / neutral detergent is a calcium sulfonate detergent, or a calcium phenate detergent. In one embodiment, the one or more detergents include a mixture of one or more low-based / neutral calcium-containing detergents and one or more overbased calcium-containing detergents.

[0110] The one or more detergents may include overbased calcium-containing detergents and low-based / neutral detergents that are salts of alkali metals or alkaline earth metals other than calcium.

[0111] The amount of calcium provided by the one or more calcium-containing detergents is greater than about 0.01 wt.%, or greater than about 0.02 wt.%, or up to about 0.25 wt.%, or from about 0.010 wt.% to about 0.25 wt.%, or from about 0.02 wt.% to about 0.20 wt.%, or from about 0.02 wt.% to about 0.15 wt.%, wherein the amount is based on the total weight of the lubricating oil composition.

[0112] The low based / neutral detergent may provide calcium in an amount that constitutes at least 0.001 wt. % of the calcium provided by the total detergents in the lubricating oil composition. In some embodiments, the low based / neutral detergent may provide calcium in an amount that constitutes at least 0.003 wt. %, or between 0.003 wt. % and 0.05 wt. % of the calcium provided by the total detergents in the lubricating oil composition.

[0113] In certain embodiments, the one or more low based / neutral detergents provide from about 1 ppmw to about 400 ppmw of calcium by weight to the lubricating oil composition, based on the total weight of the lubricating oil composition. In some embodiments, the one or more low based / neutral calcium-containing detergents provide from 1 ppmw to 350 ppmw of calcium by weight to the lubricating oil composition, based on the total weight of the lubricating oil composition.

[0114] In some embodiments, detergents are effective in suspending harmful products that are formed in the lubricating oil composition during engine use.

[0115] The detergent may be present at from about 0% to about 10% by weight, or from about 0.1% to about 8% by weight, or from about 1% to about 4% by weight, or from greater than about 4% to about 8% by weight.

[0116] Dispersants The lubricating oil composition may optionally further comprise one or more dispersants other than the dispersant viscosity modifiers discussed above. Dispersants are often referred to as ashless dispersants because they do not contain ash-forming metals prior to mixing into the lubricating oil composition and do not normally contribute ash when added to the lubricant. Ashless dispersants are characterized by having polar groups attached to a relatively high molecular weight hydrocarbon chain. Typical ashless dispersants include N-substituted long chain alkenyl succinimides. Examples of N-substituted long chain alkenyl succinimides include polyisobutylene succinimides in which the number average molecular weight of the polyisobutylene substituent ranges from about 350 to about 50,000, or up to about 5,000, or up to about 3,000, as measured by GPC. Succinimide dispersants and their preparation are disclosed, for example, in U.S. Pat. No. 7,897,696 or U.S. Pat. No. 4,234,435. The alkenyl substituent may be prepared from polymerizable monomers containing from about 2 to about 16, or from about 2 to about 8, or from about 2 to about 6 carbon atoms. Succinimide dispersants are typically imides formed from polyamines, typically poly(ethyleneamines).

[0117] Preferred amines are selected from polyamines and hydroxyamines. Examples of polyamines that may be used include, but are not limited to, diethylene triamine (DETA), triethylene tetramine (TETA), tetraethylene pentamine (TEPA), and higher homologs such as pentaethylamine hexamine (PEHA).

[0118] Suitable heavy polyamines are mixtures of polyalkylene-polyamines containing small amounts of lower polyamine oligomers such as TEPA and PEHA (pentaethylenehexamine), but primarily oligomers with 6 or more nitrogen atoms, 2 or more primary amines per molecule, and more extensive branching than conventional polyamine mixtures. Heavy polyamines preferably include polyamine oligomers containing 7 or more nitrogen atoms per molecule and having 2 or more primary amines per molecule. Heavy polyamines contain greater than 28% by weight (e.g., greater than 32% by weight) total nitrogen and an equivalent weight of 120 to 160 grams of primary amine groups per equivalent.

[0119] In some approaches, suitable polyamines, commonly known as PAM, contain a mixture of ethyleneamines, with TEPA and pentaethylenehexamine (PEHA) being the major portion of the polyamine, usually less than about 80%.

[0120] Typically, the PAM has 8.7 to 8.9 milliequivalents of primary amine per gram (115 to 112 milliequivalents per equivalent of primary amine) and a total nitrogen content of about 33% to 34% by weight. Heavier cuts of the PAM oligomers, substantially free of TEPA and containing only small amounts of PEHA, but containing primarily oligomers with more than six nitrogen atoms and more extensive branching, may produce dispersants with improved dispersancy.

[0121] In one embodiment, the present disclosure further comprises at least one polyisobutylene succinimide dispersant derived from polyisobutylene having a number average molecular weight in the range of about 350 to about 50,000, or to about 5,000, or to about 3,000, as determined by GPC. The polyisobutylene succinimide may be used alone or in combination with other dispersants.

[0122] In some embodiments, when polyisobutylene is included, the polyisobutylene may have a terminal double bond content of more than 50 mol%, more than 60 mol%, more than 70 mol%, more than 80 mol%, or more than 90 mol%. Such PIB is also referred to as highly reactive PIB ("HR-PIB"). HR-PIB having a number average molecular weight in the range of about 800 to about 5000 as determined by GPC is suitable for use in embodiments of the present disclosure. Conventional PIB typically has a terminal double bond content of less than 50 mol%, less than 40 mol%, less than 30 mol%, less than 20 mol%, or less than 10 mol%.

[0123] HR-PIB having a number average molecular weight ranging from about 900 to about 3000 as determined by GPC may be suitable. Such HR-PIB is commercially available or can be synthesized by polymerization of isobutene in the presence of a non-chlorinated catalyst such as boron trifluoride, as described in U.S. Patent No. 4,152,499 to Boerzel, et al. and U.S. Patent No. 5,739,355 to Gateau, et al. When HR-PIB is used in the thermal ene reaction, it may result in higher conversion during the reaction and less precipitate formation due to increased reactivity. A suitable method is described in U.S. Patent No. 7,897,696.

[0124] In one embodiment, the present disclosure further comprises at least one dispersant derived from polyisobutylene succinic anhydride ("PIBSA"), which may have an average of about 1.0 to about 2.0 succinic moieties per polymer.

[0125] The percent actives of the alkenyl or alkyl succinic anhydride can be determined using chromatographic techniques, which are described in U.S. Patent No. 5,334,321, columns 5 and 6.

[0126] Percent polyolefin conversion is calculated from the % actives using the formula in columns 5 and 6 of US Pat. No. 5,334,321.

[0127] Unless otherwise specified, all percentages are weight percent and all molecular weights are number average molecular weights as determined by gel permeation chromatography (GPC) using commercially available polystyrene standards (having number average molecular weights of 180 to about 18,000) as calibration standards.

[0128] In one embodiment, the dispersant may be derived from a polyalphaolefin (PAO) succinic anhydride. In one embodiment, the dispersant may be derived from an olefin maleic anhydride copolymer. As an example, the dispersant may be described as poly-PIBSA. In one embodiment, the dispersant may be derived from an anhydride grafted to an ethylene-propylene copolymer.

[0129] One type of suitable dispersant may be a Mannich base. Mannich bases are materials formed by the condensation of higher molecular weight alkyl-substituted phenols, polyalkylene polyamines, and aldehydes such as formaldehyde. Mannich bases are described in more detail in U.S. Pat. No. 3,634,515.

[0130] A suitable class of dispersants may also be high molecular weight esters or half ester amides.

[0131] Suitable dispersants may also be post-treated by conventional methods by reaction with any of a variety of agents. Among these are boron, urea, thiourea, dimercaptothiadiazole, carbon disulfide, aldehydes, ketones, carboxylic acids, hydrocarbon-substituted succinic anhydrides, maleic anhydrides, nitriles, epoxides, carbonates, cyclic carbonates, hindered phenol esters, and phosphorus compounds. U.S. Patent No. 7,645,726, U.S. Patent No. 7,214,649, and U.S. Patent No. 8,048,831 are incorporated herein by reference in their entirety.

[0132] In addition to the carbonate and boric acid post-treatments, any of the compounds may be post-treated or further post-treated with a variety of post-treatments designed to improve or impart different properties. Such post-treatments include those summarized in columns 27-29 of U.S. Patent No. 5,241,003, which is incorporated herein by reference. Such treatments include treatment with: Inorganic phosphoric acids or anhydrides (e.g., U.S. Pat. Nos. 3,403,102 and 4,648,980); Organophosphorus compounds (e.g., U.S. Pat. No. 3,502,677); Phosphorus pentasulfide; boron compounds as already mentioned above (e.g., U.S. Pat. Nos. 3,178,663 and 4,652,387); Carboxylic acids, polycarboxylic acids, anhydrides, and / or acid halides (e.g., U.S. Pat. Nos. 3,708,522 and 4,948,386); epoxides polyepoxyates or thioepoxides (e.g., U.S. Pat. Nos. 3,859,318 and 5,026,495); Aldehydes or ketones (e.g., U.S. Pat. No. 3,458,530); Carbon disulfide (e.g., U.S. Pat. No. 3,256,185); glycidol (e.g., U.S. Pat. No. 4,617,137); urea, thiourea or guanidine (e.g., U.S. Pat. Nos. 3,312,619, 3,865,813, and British Pat. No. 1,065,595); organic sulfonic acids (e.g., U.S. Pat. No. 3,189,544 and British Pat. No. 2,140,811); Alkenyl cyanides (e.g., U.S. Pat. Nos. 3,278,550 and 3,366,569); Diketene (e.g., U.S. Pat. No. 3,546,243); diisocyanates (e.g., U.S. Pat. No. 3,573,205); Alkanesultones (e.g., U.S. Pat. No. 3,749,695); 1,3-dicarbonyl compounds (e.g., U.S. Pat. No. 4,579,675); Sulfates of alkoxylated alcohols or phenols (e.g., U.S. Pat. No. 3,954,639); Cyclic lactones (e.g., U.S. Pat. Nos. 4,617,138, 4,645,515, 4,668,246, 4,963,275, and 4,971,711); cyclic carbonates or thiocarbonates, linear monocarbonates or polycarbonates, or chloroformates (e.g., U.S. Pat. Nos. 4,612,132, 4,647,390, 4,648,886, 4,670,170); Nitrogen-containing carboxylic acids (e.g., U.S. Pat. No. 4,971,598 and British Pat. No. 2,140,811); Hydroxy-protected chlorodicarbonyloxy compounds (e.g., U.S. Pat. No. 4,614,522); Lactams, thiolactams, thiolactones, or dithiolactones (e.g., U.S. Pat. Nos. 4,614,603 and 4,666,460); cyclic carbonates or thiocarbonates, linear monocarbonates or polycarbonates, or chloroformates (e.g., U.S. Pat. Nos. 4,612,132, 4,647,390, 4,646,860, and 4,670,170); Nitrogen-containing carboxylic acids (e.g., U.S. Pat. No. 4,971,598 and British Pat. No. 2,440,811); Hydroxy-protected chlorodicarbonyloxy compounds (e.g., U.S. Pat. No. 4,614,522); Lactams, thiolactams, thiolactones, or dithiolactones (e.g., U.S. Pat. Nos. 4,614,603 and 4,666,460); Cyclic carbamates, cyclic thiocarbamates, or cyclic dithiocarbamates (e.g., U.S. Pat. Nos. 4,663,062 and 4,666,459); Hydroxyaliphatic carboxylic acids (e.g., U.S. Pat. Nos. 4,482,464, 4,521,318, and 4,713,189); oxidizing agents (e.g., U.S. Pat. No. 4,379,064); Combinations of phosphorus pentasulfide and polyalkylenepolyamines (e.g., U.S. Pat. No. 3,185,647); Combinations of carboxylic acids or aldehydes or ketones and sulfur or sulfur chlorides (e.g., U.S. Pat. Nos. 3,390,086 and 3,470,098); A combination of hydrazine and carbon disulfide (e.g., U.S. Pat. No. 3,519,564); Combinations of aldehydes and phenols (e.g., U.S. Pat. Nos. 3,649,229, 5,030,249, and 5,039,307); Combinations of aldehydes and O-diesters of dithiophosphoric acids (e.g., U.S. Pat. No. 3,865,740); Combinations of hydroxyaliphatic carboxylic acids and boric acid (e.g., U.S. Pat. No. 4,554,086); A combination of hydroxyaliphatic carboxylic acids followed by formaldehyde and phenol (e.g., U.S. Pat. No. 4,636,322); Combinations of hydroxyaliphatic carboxylic acids followed by aliphatic dicarboxylic acids (e.g., U.S. Pat. No. 4,663,064); A combination of formaldehyde and phenol followed by glycolic acid (e.g., U.S. Pat. No. 4,699,724); A combination of a hydroxyaliphatic carboxylic acid or oxalic acid followed by a diisocyanate (e.g., U.S. Pat. No. 4,713,191); Combinations of inorganic acids or anhydrides of phosphorus or their partial or total sulfur analogs and boron compounds (e.g., U.S. Pat. No. 4,857,214); A combination of an organic diacid, followed by an unsaturated fatty acid, and then a nitrosoaromatic amine, optionally followed by a boron compound, and then a glycosylation agent (e.g., U.S. Pat. No. 4,973,412); Combinations of aldehydes and triazoles (e.g., U.S. Pat. No. 4,963,278); A combination of an aldehyde and a triazole followed by a boron compound (e.g., U.S. Pat. No. 4,981,492); Combinations of cyclic lactones and boron compounds (e.g., U.S. Pat. Nos. 4,963,275 and 4,971,711), which are incorporated herein by reference in their entireties.

[0133] Suitable dispersants may have a TBN of about 10 to about 65 without oil, which is equivalent to a TBN of about 5 to about 30 when measured on a dispersant sample containing about 50% diluent oil. TBN is measured by the method of ASTM D2896.

[0134] Dispersants, when present, may be used in an amount sufficient to provide up to about 20% by weight, based on the final weight of the lubricating oil composition. Alternative amounts of dispersant that may be used may be from about 0.1% to about 15% by weight, or from about 0.1% to about 10% by weight, or from about 0.1% to about 8% by weight, or from about 1% to about 10% by weight, or from about 1% to about 8% by weight, or from about 1% to about 6% by weight, based on the final weight of the lubricating oil composition. In some embodiments, the lubricating oil composition utilizes a mixed dispersant system. A single type or a mixture of two or more types of dispersants in any desired ratio may be used.

[0135] Friction modifiers The lubricating oil composition herein may optionally contain one or more friction modifiers. Suitable friction modifiers may include metal-containing and metal-free friction modifiers, but may include, but are not limited to, imidazolines, amides, amines, succinimides, alkoxylated amines, alkoxylated ether amines, amine oxides, amidoamines, nitriles, betaines, quaternary amines, imines, amine salts, aminoguanidines, alkanolamides, phosphonates, metal-containing compounds, glycerol esters, sulfurized fatty compounds and olefins, sunflower oil, other naturally occurring vegetable or animal oils, dicarboxylic acid esters, esters or partial esters of polyols with one or more aliphatic or aromatic carboxylic acids, and the like.

[0136] Suitable friction modifiers may contain hydrocarbyl groups selected from linear, branched, or aromatic hydrocarbyl groups, or mixtures thereof, and may be saturated or unsaturated. The hydrocarbyl groups may be composed of carbon and hydrogen or heteroatoms such as sulfur or oxygen. The hydrocarbyl groups may range from about 12 to about 25 carbon atoms. In some embodiments, the friction modifier may be a long chain fatty acid ester. In other embodiments, the long chain fatty acid ester may be a mono-ester, or a di-ester, or a (tri)glyceride. The friction modifier may be a long chain fatty amide, a long chain fatty ester, a long chain fatty epoxide derivative, or a long chain imidazoline.

[0137] Other suitable friction modifiers may include organic, ashless (metal-free), nitrogen-free mechanical friction modifiers. Such friction modifiers include esters formed by reacting carboxylic acids and anhydrides with alkanols, and may generally include polar end groups (e.g., carboxyl or hydroxyl) covalently attached to an oleophilic hydrocarbon chain. An example of an organic ashless, nitrogen-free friction modifier is generally known as glycerol monooleate (GMO), which may include mono-, di-, and tri-esters of oleic acid. Other suitable friction modifiers are described in U.S. Patent No. 6,723,685, the entirety of which is incorporated herein by reference.

[0138] Aminic friction modifiers may include amines or polyamines. Such compounds may have hydrocarbyl groups that are linear, either saturated or unsaturated, or a mixture thereof, and may contain from about 12 to about 25 carbon atoms. Further examples of suitable friction modifiers include alkoxylated amines and alkoxylated ether amines. Such compounds may have hydrocarbyl groups that are linear, either saturated or unsaturated, or a mixture thereof. They may contain from about 12 to about 25 carbon atoms. Examples include ethoxylated amines and ethoxylated ether amines.

[0139] The amines and amides may be used by themselves or in the form of adducts or reaction products with boron compounds such as boron oxides, boron halides, metaborates, boric acid or mono-, di-, or tri-alkyl borates. Other suitable friction modifiers are described in U.S. Patent No. 6,300,291, which is incorporated herein by reference in its entirety.

[0140] Friction modifiers may optionally be present in ranges such as from about 0% to about 10% by weight, or from about 0.01% to about 8% by weight, or from about 0.1% to about 4% by weight.

[0141] Molybdenum-Containing Components The lubricating oil composition herein may also optionally contain one or more molybdenum-containing compounds. The oil-soluble molybdenum compounds may have the functional properties of antiwear agents, antioxidants, friction modifiers, or mixtures thereof. The oil-soluble molybdenum compounds may include molybdenum dithiocarbamates, molybdenum dialkyldithiophosphates, molybdenum dithiophosphinates, amine salts of molybdenum compounds, molybdenum xanthates, molybdenum thioxanthates, molybdenum sulfides, molybdenum carboxylates, molybdenum alkoxides, trinuclear organomolybdenum compounds, and / or mixtures thereof. The molybdenum sulfides include molybdenum disulfide. The molybdenum disulfide may be in the form of a stable dispersion. In one embodiment, the oil-soluble molybdenum compounds may be selected from the group consisting of molybdenum dithiocarbamates, molybdenum dialkyldithiophosphates, amine salts of molybdenum compounds, and mixtures thereof. In one embodiment, the oil soluble molybdenum compound can be a molybdenum dithiocarbamate.

[0142] Suitable examples of molybdenum compounds that can be used include commercially available materials sold under trade names such as Molyvan 822™, Molyvan™ A, Molyvan 2000™, and Molyvan 855™ from R.T. Vanderbilt Co., Ltd., and Sakura-Lube™ S-165, S-200, S-300, S-310G, S-525, S-600, S-700, and S-710 available from Adeka Corporation, and mixtures thereof. Suitable molybdenum components are described in U.S. Patent No. 5,650,381, U.S. Reissue Patent Nos. 37,363 (E1), 38,929 (E1), and 40,595 (E1), the entireties of which are incorporated herein by reference.

[0143] Additionally, the molybdenum compound can be an acidic molybdenum compound, including molybdic acid, ammonium molybdate, sodium molybdate, potassium molybdate, and other alkali metal molybdates, and other molybdenum salts, such as sodium hydrogen molybdate, MoOCl4, MoO2Br2, Mo2O3Cl6, molybdenum trioxide, or similar acidic molybdenum compounds. Alternatively, the composition can provide the molybdenum via molybdenum / sulfur complexes of basic nitrogen compounds, as described, for example, in U.S. Pat. Nos. 4,263,152, 4,285,822, 4,283,295, 4,272,387, 4,265,773, 4,261,843, 4,259,195, and 4,259,194, and WO 94 / 06897, the foregoing patents being incorporated herein by reference in their entireties.

[0144] Another class of suitable organomolybdenum compounds are trinuclear molybdenum compounds and mixtures thereof, such as compounds of the formula Mo3SkLnQz, where S represents sulfur, L represents an independently selected ligand having a sufficient number of carbon atoms in the organic group to render the compound soluble or dispersible in oil, n is 1-4, k varies from 4-7, Q is selected from the group of neutral electron donor compounds such as water, amines, alcohols, phosphines, and ethers, and z ranges from 0-5, including non-stoichiometric values. There may be at least 21 total carbon atoms in the organic groups of all the ligands, such as at least 25, at least 30, or at least 35 carbon atoms. Additional suitable molybdenum compounds are described in U.S. Pat. No. 6,723,685, which is incorporated herein by reference in its entirety.

[0145] The oil soluble molybdenum compound may be present in an amount sufficient to provide from about 0.5 ppm to about 2000 ppm, from about 1 ppm to about 700 ppm, from about 1 ppm to about 550 ppm, from about 5 ppm to about 300 ppm, or from about 20 ppm to about 250 ppm of molybdenum.

[0146] Transition metal-containing compounds In another embodiment, the oil-soluble compound can be a transition metal-containing compound or metalloid. Transition metals can include, but are not limited to, titanium, vanadium, copper, zinc, zirconium, molybdenum, tantalum, tungsten, etc. Suitable metalloids include, but are not limited to, boron, silicon, antimony, tellurium, etc.

[0147] In one embodiment, the oil-soluble transition metal-containing compound can function as an anti-wear agent, a friction modifier, an antioxidant, an adhesion control additive, or two or more of these functions. In one embodiment, the oil-soluble transition metal-containing compound can be an oil-soluble titanium compound, such as a titanium (IV) alkoxide. Among the titanium-containing compounds that can be used in or for the preparation of oil-soluble materials in the technology of the present disclosure, include various Ti (IV) compounds, such as titanium (IV) oxide; titanium (IV) sulfide; titanium (IV) nitrate; titanium (IV) alkoxides, such as titanium methoxide, titanium ethoxide, titanium propoxide, titanium isopropoxide, titanium butoxide, titanium 2-ethylhexoxide; and other titanium compounds or complexes, such as, but not limited to, titanium phenate; titanium carboxylates, such as titanium (IV) 2-ethyl-1,3-hexanedioate or titanium citrate or titanium oleate; and titanium (IV) (triethanolaminato) isopropoxide. Other forms of titanium encompassed by the disclosed technology include titanium phosphates, such as titanium dithiophosphates (e.g., dialkyl dithiophosphates) and titanium sulfonates (e.g., alkyl benzene sulfonates), or generally reaction products of titanium compounds with various acid materials to form salts, such as oil-soluble salts. Thus, titanium compounds may be derived from organic acids, alcohols, and glycols, among others. Ti compounds may also exist in dimeric or oligomeric forms containing Ti-O-Ti structures. Such titanium materials are commercially available or can be readily prepared by suitable synthetic techniques that will be apparent to those skilled in the art. They may exist at room temperature as solids or liquids, depending on the particular compound. They may also be provided in solution form in a suitable inert solvent.

[0148] In one embodiment, titanium may be provided as a Ti-modified dispersant, such as a succinimide dispersant. Such materials may be prepared by forming a titanium mixed anhydride between a titanium alkoxide and a hydrocarbyl-substituted succinic anhydride, such as an alkenyl-(or alkyl) succinic anhydride. The resulting titanate-succinate intermediate may be used directly or may be reacted with any of a number of materials, such as (a) polyamine-based succinimide / amide dispersants having free condensable -NH functional groups; (b) components of polyamine-based succinimide / amide dispersants, i.e., alkenyl (or alkyl) succinic anhydrides and polyamines; (c) hydroxy-containing polyester dispersants prepared by reaction of substituted succinic anhydrides with polyols, amino alcohols, polyamines, or mixtures thereof. Alternatively, the titanate-succinate intermediate can be reacted with other agents such as alcohols, amino alcohols, ether alcohols, polyether alcohols or polyols, or fatty acids, and the product can be used directly to impart Ti to a lubricant or can be further reacted with a succinic dispersant as described above. As an example, one part (mol) of tetraisopropyl titanate can be reacted with about two parts (moles) of polyisobutene-substituted succinic anhydride at 140-150°C for 5-6 hours to provide a titanium modified dispersant or intermediate. The resulting material (30 g) can be further reacted with a succinimide dispersant from a polyisobutene-substituted succinic anhydride and polyethylene polyamine mixture (127 grams + diluent oil) at 150°C for 1.5 hours to produce a titanium modified succinimide dispersant.

[0149] Another titanium-containing compound is titanium alkoxide and C6-C 25 It may be a reaction product with a carboxylic acid. The reaction product has the following formula:

[0150] [ka] wherein n is an integer selected from 2, 3, and 4, and R is a hydrocarbyl group containing from about 5 to about 24 carbon atoms, or the following formula:

[0151] [ka] where m+n=4, n ranges from 1 to 3, R4 is an alkyl moiety having from 1 to 8 carbon atoms, R1 is selected from hydrocarbyl groups containing from about 6 to 25 carbon atoms, and R2 and R3 are the same or different and are selected from hydrocarbyl groups containing from 1 to 6 carbon atoms, or a compound of the formula:

[0152] [ka] (wherein x ranges from 0 to 3; R1 is selected from hydrocarbyl groups containing about 6 to 25 carbon atoms; R2 and R3 are the same or different and are selected from hydrocarbyl groups containing about 1 to 6 carbon atoms; R4 is H, C6 to C 25 The carboxylic acid moiety may be selected from the group consisting of

[0153] Suitable carboxylic acids may include, but are not limited to, caproic acid, caprylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachic acid, oleic acid, erucic acid, linoleic acid, linolenic acid, cyclohexanecarboxylic acid, phenylacetic acid, benzoic acid, neodecanoic acid, and the like.

[0154] In one embodiment, the oil soluble titanium compound may be present in the lubricating oil composition in an amount to provide from about 0 to about 3000 ppm by weight of titanium, or from 25 to about 1500 ppm by weight of titanium, or from about 35 ppm to about 500 ppm by weight of titanium, or from about 50 ppm to about 300 ppm.

[0155] Other optional additives Other additives may be selected to perform one or more functions required in a lubricating fluid. Additionally, one or more of the aforementioned additives may be multifunctional and may provide functions in addition to or other than those described herein.

[0156] The lubricating oil composition according to the present disclosure may optionally contain other performance additives. The other performance additives may be in addition to the specific additives of the present disclosure and / or may include one or more of metal deactivators, viscosity index improvers, detergents, ashless TBN boosters, friction modifiers, antiwear agents, corrosion inhibitors, rust inhibitors, dispersants, dispersant viscosity index improvers, extreme pressure agents, antioxidants, foam suppressants, demulsifiers, emulsifiers, pour point depressants, seal swell agents, and mixtures thereof. Typically, a fully formulated lubricating oil will contain one or more of these performance additives.

[0157] Suitable metal deactivators may include derivatives of benzotriazole (typically tolyltriazole), dimercaptothiadiazole derivatives, 1,2,4-triazole, benzimidazole, 2-alkyldithiobenzimidazole, or 2-alkyldithiobenzothiazole; foam suppressors including copolymers of ethyl acrylate and 2-ethylhexyl acrylate and optionally vinyl acetate; demulsifiers including trialkyl phosphates, polyethylene glycol, polyethylene oxide, polypropylene oxide, and (ethylene oxide-propylene oxide) polymers; pour point depressants including esters of maleic anhydride-styrene, polymethacrylates, polyacrylates, or polyacrylamides.

[0158] Suitable suds suppressors include silicon-based compounds such as siloxanes.

[0159] Suitable pour point depressants may include polymethyl methacrylate or mixtures thereof. The pour point depressant may be present in an amount sufficient to provide from about 0 wt. % to about 1 wt. %, from about 0.01 wt. % to about 0.5 wt. %, or from about 0.02 wt. % to about 0.04 wt. %, based on the final weight of the lubricating oil composition.

[0160] A suitable rust inhibitor can be a single compound or a mixture of compounds that have the property of inhibiting corrosion of ferrous metal surfaces. Non-limiting examples of rust inhibitors useful herein include oil-soluble high molecular weight organic acids such as 2-ethylhexanoic acid, lauric acid, myristic acid, palmitic acid, oleic acid, linoleic acid, linolenic acid, behenic acid, and cerotic acid, as well as oil-soluble polycarboxylic acids including dimer and trimer acids such as those produced from tall oil fatty acids, oleic acid, and linoleic acid. Other suitable corrosion inhibitors include long chain alpha, omega-dicarboxylic acids in the molecular weight range of about 600 to about 3000, and alkenyl succinic acids in which the alkenyl group contains about 10 or more carbon atoms, such as tetrapropenyl succinic acid, tetradecenyl succinic acid, and hexadecenyl succinic acid. Another useful type of acidic corrosion inhibitor is the half ester of an alkenyl succinic acid having about 8 to about 24 carbon atoms in the alkenyl group with an alcohol, such as a polyglycol. The corresponding half amides of such alkenyl succinic acids are also useful. Useful rust inhibitors are high molecular weight organic acids. In some embodiments, the engine oil does not contain a rust inhibitor.

[0161] When present, the rust inhibitor may be used in an amount sufficient to provide from about 0 wt. % to about 5 wt. %, from about 0.01 wt. % to about 3 wt. %, from about 0.1 wt. % to about 2 wt. %, based on the final weight of the lubricating oil composition.

[0162] Generally speaking, a suitable crankcase lubricant may contain additive components in the ranges listed in the table below.

[0163] [Table 2]

[0164] The percentages of each component above represent the weight percent of each component based on the weight of the final lubricant composition, with the remainder of the lubricant composition consisting of one or more base oils.

[0165] The additives used in formulating the compositions described herein may be blended into the base oil individually or in various partial combinations, however, it may be preferred to use an additive concentrate (i.e., additives plus a diluent such as a hydrocarbon solvent) and blend all of the components simultaneously. EXAMPLES

[0166] The following examples illustrate, but do not limit, the methods and compositions of the present disclosure. Other suitable modifications and adaptations of the various conditions and parameters normally encountered in the art and obvious to those skilled in the art are within the spirit and scope of the present disclosure. All patents and publications cited herein are hereby fully incorporated by reference in their entirety.

[0167] Each of the lubricating oil compositions contained a major amount of base oil and a base conventional dispersant inhibitor (DI) package. The DI package contained conventional amounts of dispersants, antiwear additives, antioxidants, friction modifiers, antifoam agents, process oils, viscosity index improvers, and pour point depressants, as provided in Table 3 below. Specifically, the DI package contained succinimide dispersants, molybdenum-containing compounds, antioxidants, and antifoam agents. The majority of the base oils were a mixture of Group II and Group III base oils. The components that were modified are specified in the example tables and discussion below. All values ​​listed are stated as weight percent of the component in the lubricating oil composition (i.e., active stock plus diluent oil, if any) unless otherwise specified.

[0168] [Table 3]

[0169] The lubricating oil compositions were tested according to the Sequence VH Engine Test. The Sequence VH Test (ASTM D8256) is a test method used to evaluate engine deposit control by automotive engine oils under operating conditions purposefully selected to accelerate deposit formation. The engine is a gasoline-fueled spark ignition engine operated under low temperature, light load conditions. A 2013 Ford 4.6 L fuel-injected 8-cylinder gasoline engine with roller followers, coolant jacketed rocker covers, and camshaft baffles is used.

[0170] The test duration was 216 hours with 54 cycles, each consisting of three different operating phases as shown in Table 4 below: Fuel containing sludge precursors was used to intentionally increase engine blow-by; Rocker cover jacket temperatures were cycled.

[0171] [Table 4]

[0172] One of the measurements included in the Sequence VH test is the Average Engine Varnish (AEV) measurement. It evaluates varnish deposits on the piston skirts (thrust) and rocker arm cover baffles. According to the Sequence VH test parameters, the oil passes the AEV test in 8.6 minutes or better. The results of the AEV test are shown in Table 5 below.

[0173] [Table 5] 1- The viscosity modifier was a non-dispersant ethylene propylene copolymer with an SSI of about 25.

[0174] The data in Table 5 demonstrates that there is improved resistance to varnish formation for lubricating oil compositions comprising greater than 50 wt. % of a base oil of lubricating viscosity and an additive composition comprising one or more zinc dialkyldithiophosphates (ZDDP compounds) and one or more viscosity modifiers, the additive composition comprising one or more Zinc Dialkyldithiophosphates (ZDDP compounds) and one or more viscosity modifiers, the amount of phosphorus (P) in weight percent provided to the lubricating oil composition by the one or more ZDDP compounds divided by the amount of the one or more viscosity modifiers (VM) in weight percent is a P / VM quotient of greater than about 0.0075. This is evident from the higher average engine varnish values ​​for Inventive Examples IE-1 to IE-5 when compared to the values ​​for Comparative Examples CE-1 to CE-2.

[0175] The data in Table 5 also demonstrates that for lubricating oil compositions formulated with a P / VM quotient greater than about 0.0075 and VM amounts less than 14 wt.%, there is improved resistance to varnish formation, as evidenced by the higher average engine varnish values ​​for Inventive Examples IE-1 to IE-5 when compared to the values ​​for Comparative Examples CE-1 to CE-2.

[0176] In addition, the data in Table 5 also demonstrates that there is improved resistance to varnish formation for lubricating oil compositions formulated with a P / VM quotient greater than about 0.0075 and an amount of at least 0.064 wt. % P. This is evident from the higher average engine varnish values ​​for Inventive Examples IE-2 to IE-5 when compared to the values ​​for Comparative Examples CE-1 to CE-2.

[0177] Other embodiments of the present disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the embodiments disclosed herein. As used throughout the specification and claims, "a" and / or "an" and / or "the" can refer to one or more than one. Unless otherwise indicated, all numbers expressing quantities, proportions, percentages, or other numerical values ​​should be understood in all instances as being modified by the term "about". Accordingly, unless indicated to the contrary, the numerical parameters set forth in the specification and claims are approximations that may vary depending on the desired properties sought to be obtained by the present disclosure. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should be construed at least in light of the number of reported significant digits and by applying ordinary rounding techniques.

[0178] It is understood that each component, compound, substituent, or parameter disclosed herein should be construed as disclosed for use alone or in combination with one or more of any and all other components, compounds, substituents, or parameters disclosed herein.

[0179] It is further to be understood that each range disclosed herein should be construed as a disclosure of each specific value within the disclosed range having the same number of significant digits. Thus, for example, a range of 1 to 4 should be construed as an explicit disclosure of the values ​​1, 2, 3, and 4, and any range of such values.

[0180] It is further understood that each lower limit of each range disclosed herein should be interpreted as being disclosed in combination with each upper limit of each range and each specific value within each range disclosed herein for the same component, compound, substituent, or parameter. Thus, the present disclosure should be interpreted as a disclosure of all ranges derived by combining each lower limit of each range with each upper limit of each range or each specific value within each range, or by combining each upper limit of each range with each specific value within each range. That is, it is further understood that any range between the endpoint values ​​within the broad range is also contemplated herein. Thus, a range of 1 to 4 also means a range of 1 to 3, 1 to 2, 2 to 4, 2 to 3, etc.

[0181] Furthermore, a specific amount / value of a component, compound, substituent, or parameter disclosed in the description or examples should be construed as a disclosure of either a lower or upper limit of a range and therefore can be combined with any other lower or upper limit or specific amount / value in a range for the same component, compound, substituent, or parameter disclosed elsewhere in this application to form a range for that component, compound, substituent, or parameter.

Claims

1. 1. A lubricating oil composition comprising greater than 50 weight percent of a base oil of lubricating viscosity; and an additive composition comprising: an amount of one or more zinc dialkyldithiophosphates (ZDDP compounds) and an amount of one or more viscosity modifiers, wherein the amount of phosphorus (P) in weight percent provided to the lubricating oil composition by the one or more ZDDP compounds divided by the amount of the one or more viscosity modifiers (VM) in weight percent based on a total weight of the lubricating oil composition is a P / VM quotient of greater than about 0.0075; and an additive composition, wherein the viscosity modifier is a polyolefin having a Shear Stability Index (SSI) of 3% to 60%, as measured using test method ASTM-D6278.

2. 2. The lubricating oil composition of claim 1, wherein the P / VM quotient is greater than about 0.0077.

3. 2. The lubricating oil composition of claim 1, wherein the P / VM quotient is greater than about 0.0075 and the amount of VM is less than 14 wt.%.

4. 2. The lubricating oil composition of claim 1, wherein the P / VM quotient is greater than about 0.0075 and the amount of P is at least 0.064 wt.%.

5. 2. The lubricating oil composition of claim 1, wherein the one or more ZDDP compounds are derived from one or more secondary alkyl alcohols having an alkyl group having from 3 to 8 carbon atoms.

6. 2. The lubricating oil composition of claim 1, wherein the one or more ZDDP compounds are derived from two or more secondary alkyl alcohols.

7. 2. The lubricating oil composition of claim 1, wherein the one or more ZDDP compounds are derived from one or more primary alkyl alcohols, each having an alkyl group having from 3 to 8 carbon atoms.

8. 8. The lubricating oil composition of claim 7, wherein the alkyl group of the one or more primary alkyl alcohols has a branch at a beta carbon relative to the hydroxyl group.

9. 2. The lubricating oil composition of claim 1, wherein the one or more ZDDP compounds are derived from two or more primary alkyl alcohols.

10. 2. The lubricating oil composition of claim 1, wherein the one or more ZDDP compounds is a mixture of at least one ZDDP compound derived from 100% primary alcohol and at least one ZDDP compound derived from 100% secondary alcohol.

11. The lubricating oil composition of claim 1, wherein the polyolefin is an ethylene-alpha olefin copolymer or a diene polymer.

12. The lubricating oil composition of claim 11, wherein the polyolefin has a polydispersity (Mw / Mn) in the range of about 1.5 to about 10.

13. The lubricating oil composition of claim 11, wherein the polyolefin has a Shear Stability Index (SSI) of 3% to 30%, as measured using test method ASTM-D6278.

14. 10. The lubricating oil composition of claim 1, further comprising at least one additive selected from the group consisting of dispersants, antioxidants, antiwear agents, antifoam agents, molybdenum-containing compounds, titanium-containing compounds, phosphorus-containing compounds, pour point depressants, and diluent oils.

15. 10. The lubricating oil composition of claim 1, wherein the lubricating oil composition provides an average Engine Varnish Test (ASTM D8256) result of 8.6 or greater.

16. 13. A method of extending the oil drain interval of an internal combustion engine, comprising adding to said engine the lubricating oil composition of claim 1 and operating said engine.

17. 13. A method for reducing engine deposits in an internal combustion engine comprising adding to the engine the lubricating oil composition of claim 1 and operating the engine.

18. 1. A process for improving engine deposit resistance in an engine oil, comprising incorporating an amount of one or more zinc dialkyldithiophosphates (ZDDP compounds) and an amount of one or more viscosity modifiers into a base oil to form an engine oil, wherein the amount of phosphorus (P) in weight percent provided to the lubricating oil composition by the one or more ZDDP compounds divided by the amount of the one or more viscosity modifiers (VM) in weight percent based on a total weight of the lubricating oil composition is a P / VM quotient of greater than about 0.0075; The process wherein the viscosity modifier is a polyolefin having a Shear Stability Index (SSI) of about 3% to less than 60%, as measured using test method ASTM-D6278.

Images