Nitrogen-containing and sulfur-containing additive in electric vehicle oil

Abstract

An electric driveline oil is described. The oil includes a major amount of an oil of lubricating viscosity and an electric drive train additive. The electric driveline additive includes a nitrogen-containing or sulfur-containing additive or a derivative thereof. An amount of the electric driveline additive is from about 0.001 wt% to about 1.5 wt% based on a total weight of the electric driveline oil.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to lubricant additive compositions and lubricating oil compositions containing these compositions. More specifically, these compositions provide improved protection against wear, friction, and / or fatigue in electric vehicles. BACKGROUND

[0002] Wear, friction, and / or fatigue can be a major problem in traditional internal combustion engines. In automobiles that utilize electric motors that rely on planetary gears (e.g., electric or hybrid vehicles), these problems can also become major problems. Unlike traditional automobiles, electric and / or hybrid vehicles present some unique challenges, particularly because the electric motor and transmission typically share the same lubricating fluid. SUMMARY

[0003] In one aspect, the present disclosure relates to an electric driveline oil comprising: (a) a major amount of an oil of lubricating viscosity; and (b) an electric driveline additive comprising a nitrogen- or sulfur-containing additive or derivatives thereof; wherein the amount of the electric driveline additive is from about 0.001 wt % to about 1.5 wt %, based on the total weight of the electric driveline oil.

[0004] In another aspect, the present disclosure relates to a method of improving the wear, friction, or fatigue performance of an engine featuring an electric driveline, the method comprising lubricating the engine with an electric driveline oil comprising: (a) a major amount of an oil of lubricating viscosity; and (b) an electric driveline additive comprising a nitrogen- or sulfur-containing compound or derivatives thereof; wherein the amount of the electric driveline additive is from about 0.001 wt % to about 1.5 wt %, based on the total weight of the electric driveline oil. DETAILED DESCRIPTION

[0005] Definitions Unless otherwise indicated, the following terms are used throughout the specification and have the following meanings.

[0006] The term "major amount" of base oil refers to a case where the amount of base oil is at least 40 wt % of the lubricating oil composition. In some embodiments, the "major amount" of base oil refers to a case where the amount of base oil is greater than 50 wt %, greater than 60 wt %, greater than 70 wt %, greater than 80 wt %, or greater than 90 wt % of the lubricating oil composition.

[0007] "HOB" refers to high overbasedness with a TBN higher than 250 based on active material, while "LOB" refers to low overbasedness with a TBN lower than 100 based on active material.

[0008] The term "total base number" or "TBN" refers to the alkalinity level in an oil sample, which indicates the composition's ability to continue neutralizing corrosive acids, according to ASTM Standard No. D2896 or equivalent procedure. This test measures the change in conductivity, and the result is expressed as mg KOH / g (milliequivalents of KOH needed to neutralize 1 gram of product). Thus, a high TBN reflects a strongly overbased product, and thus a higher reserve of base for neutralizing acids.

[0009] As used herein, EV oil refers to electric drive oil used in electric vehicles equipped with wet EV electric machines. Electric drive oil is similar to transmission oil (used in conventional cars), but often has one or more additional functions (e.g., acts as a coolant for the EV electric machine, provides electrical resistivity, etc.). The one or more additional functions can present unique challenges to formulating EV oil.

[0010] The present application relates to a nitrogen- or sulfur-containing additive and / or a lubricating oil composition (e.g., electric drive system oil) comprising the nitrogen- or sulfur-containing additive. The composition is suitable for use in a car that includes an electric drive system (i.e., a car equipped with an electric motor). More specifically, the lubricating oil composition comprises a nitrogen- or sulfur-containing additive. In some embodiments, the lubricating oil composition comprises a nitrogen- or sulfur-containing additive (electric drive system additive) and a highly overbased sulfonate detergent. As one advantage, these compositions exhibit enhanced protection against wear, friction, and / or fatigue.

[0011] In some additional embodiments, the lubricating oil composition of the present application can provide protection against fatigue, wear, and / or friction in a hybrid car or plug-in hybrid car equipped with an electric motor.

[0012] Nitrogen- or sulfur-containing additive The lubricating oil composition of the present disclosure comprises an electric drive system additive that includes a nitrogen- or sulfur-containing additive or a cyclic derivative thereof. In some embodiments, the nitrogen- or sulfur-containing additive is an alkyl polyol containing one or more nitrogen or sulfur atoms. In embodiments, the nitrogen- or sulfur-containing additive is an alkyl polyol containing 25 carbons or fewer, such as 24 carbons or fewer, 23 carbons or fewer, 22 carbons or fewer, 21 carbons or fewer, 20 carbons or fewer, 19 carbons or fewer, 18 carbons or fewer, 17 carbons or fewer, or 16 carbons or fewer.

[0013] In some embodiments, the nitrogen-containing additive includes a polyol amine, a polyol amide, or a hydroxy amino ether.

[0014] Polyol amines In some embodiments, the electric driveline system additive includes a polyol amine. The polyol amine has at least 2 hydroxyl groups.

[0015] In some embodiments, the polyol amine has the following general structure: where X, Y, and Z are independently an amine, an alcohol, a hydrocarbyl amine, or a hydrocarbyl alcohol group, and where at least two of X, Y, and Z are an alcohol or a hydrocarbyl alcohol group, and where at least one of X, Y, and Z is an amine or a hydrocarbyl amine. As described above, the total carbon number of the polyol amine is 25 carbons or less.

[0016] Specific examples of polyol amines include, for example, 3-aminopropane-l,2-diol (Structure Al), 2-aminopropane-l,3-diol (Structure A2), and 3-(dimethylamino)propane-l,2-diol (Structure A3). In some embodiments, the polyol amine includes at least one 1,2-diol moiety (e.g., Structure Al). In some embodiments, the polyol amine includes at least one 1,3-diol moiety (e.g., Structure A2).

[0017] Polyol amides In some embodiments, the electric driveline system additive includes a polyol amide. The polyol amide can have the following general structure B: Structure B where each R is independently H or a hydrocarbyl group having 20 carbons or less.

[0018] Specific polyol amides include, for example, 2,3-dihydroxypropanamide (Structure Bl), N-ethyl-2,3-dihydroxypropanamide (Structure B2), 2,3-dihydroxy-N- isopropylpropanamide (Structure B3), and N,N-diethyl-2,3-dihydroxypropanamide (Structure B4).

[0019] Hydroxy amino ethers In some embodiments, the electric driveline system additive includes a hydroxyl amino ether. The hydroxyl amino ether can have the following general structure: where A and B are independently an alcohol, a hydrocarbyl alcohol, a polyol, an amine, a hydrocarbyl amine, an ether alcohol, or an ether amine, where at least one of A and B is an amine or a hydrocarbyl amine. In some embodiments, the hydroxyl amino ether contains 25 carbons or less.

[0020] Particular hydroxyl aminic ethers include, for example, 2-(2-aminoethoxy)ethan-1-ol (Structure CI) and 2-(2-(2-aminoethoxy)ethoxy)ethan-1-ol (Structure C2).

[0021] Sulfur-containing polyols Particular examples of sulfur-containing polyols include thioglycerol (Structure DI), thione (Structure D2), thioether (Structure D3 or D4 when x = 1), disulfide (Structure D3 or D4 when x = 2), and polysulfide (Structure D3 or D4 when x = 3). For Structure D3 or D4, x is an integer from 1 to 10. R is a hydrocarbyl group having 22 carbons or fewer.

[0022] Cyclic derivatives Cyclic derivatives can be formed by condensation reactions of nitrogen- or sulfur-containing additives with ketones, aldehydes, and the like. In some embodiments, the cyclic derivatives have 5-, 6-, 7-, or 8-membered rings. Particular cyclic derivatives include, for example, 2-methyl-1,3-dioxolan-4-amine (Structure El), 2,2-dimethyl-1,3-dioxolan-4-amine (Structure E2), 2-methyl-1,3-dioxolan-4-thiol (Structure E3), 2,2-dimethyl-1,3-dioxolan-4-thiol (Structure E4), and 1-(2-methyl-1,3-dioxolan-4-yl)ethane-1 -thione (Structure E5).

[0023] Without being limited by theory, it is believed that the chirality of one or more carbon atoms of each additive compound can greatly affect its performance.

[0024] The precise amount of the electric motor drive system additive can vary depending on the particular composition and amount of the oil or lubricating viscosity, the particular detergent and amount, and other desired properties of the lubricating oil composition. In some embodiments, the amount of the electric motor drive system additive is at least about 0.001 wt.%, or at least about 0.05 wt.%, or at least about 0.1 wt.%, or at least about 0.3 wt.%, or at least about 0.4 wt.%, or at least about 0.4 wt.%, or at least about 0.5 wt.%, or at least about 0.75 wt.%, or at least about 1.0 wt.%, and up to about 1.5 wt.%, or up to about 1.25 wt.%, or up to about 1.0 wt., or up to about 0.9 wt.%, or up to about 0.8 wt.%, based on the total weight of the lubricating oil composition.

[0025] Detergents In some embodiments, the lubricating oil composition comprises a metal sulfonate detergent. The metal can be any metal suitable for making a sulfonate detergent. Non-limiting examples of suitable metals include alkali metals, alkaline earth metals, and transition metals. In some embodiments, the metal is Ca, Mg, Ba, K, Na, Li, and the like.

[0026] Generally, the amount of detergent is about 0.001 wt% to about 10 wt%, about 0.05 wt% to about 3 wt%, or about 0.1 wt% to about 1 wt%, based on the total weight of the lubricating oil composition.

[0027] Optionally, the lubricating oil composition can include additional detergents generally known in the art. Some suitable detergents have been described in Mortier et al., “Chemistry and Technology of Lubricants”, 2ndEdition, London, Springer, Chapter 3, pages 75-85 (1996); and Leslie R. Rudnick, “Lubricant Additives: Chemistry and Applications,” New York, Marcel Dekker, Chapter 4, pages 113-136 (2003), which are incorporated herein by reference. Examples of these detergents include phenates, salicylates, phosphonates, and the like.

[0028] In some embodiments, the detergent comprises at least one highly overbased (TBN higher than 250 based on actives) sulfonate detergent, such as highly overbased calcium sulfonate.

[0029] Overbased metal detergents are typically produced by carbonating a mixture of a hydrocarbon, a detergent acid (e.g., sulfonic acid, alkylhydroxybenzoate, etc.), a metal oxide or hydroxide (e.g., calcium oxide or calcium hydroxide), and a promoter such as xylene, methanol, and water. For example, to make overbased calcium sulfonate, during carbonation, calcium oxide or calcium hydroxide reacts with gaseous carbon dioxide to form calcium carbonate. The sulfonic acid is neutralized with an excess of CaO or Ca(OH)2to form the sulfonate.

[0030] Generally, the overbased detergents can be low overbased (LOB), such as overbased salts having a TBN of less than 100 based on active material. In one aspect, the TBN of the low overbased salt can be from about 10 to about 100. In another aspect, the TBN of the low overbased salt can be from about 10 to about 80. The overbased detergents can be medium overbased (MOB), such as overbased salts having a TBN of from about 100 to about 250 based on active material. In one aspect, the TBN of the medium overbased salt can be from about 100 to about 200. In another aspect, the TBN of the medium overbased salt can be from about 125 to about 175. The overbased detergents can be high overbased (HOB), such as overbased salts having a TBN of greater than 250 based on active material. In one aspect, the TBN of the high overbased salt can be from about 250 to about 800 based on active material.

[0031] Other Additives Optionally, the lubricating oil composition can further include at least an additive or modifier (hereinafter “additive”) that can impart or improve any desired property of the lubricating oil composition. Any additive known to one of ordinary skill in the art can be used in the lubricating oil compositions disclosed herein. Some suitable additives are described in Mortier et al., “Chemistry and Technology of Lubricants”, 2ndEdition, London, Springer, (1996) and Leslie R. Rudnick, “Lubricant Additives: Chemistry and Applications”, New York, Marcel Dekker (2003), which are incorporated herein by reference. In some embodiments, the additive can be selected from the group consisting of antioxidants, antiwear agents, detergents, rust inhibitors, demulsifiers, friction modifiers, multifunctional additives, viscosity index improvers, pour point depressants, foam inhibitors, metal deactivators, dispersants, corrosion inhibitors, lubricity improvers, thermal stability improvers, anti-mist additives, freeze point depressants, dyes, markers, static dissipative agents, biocides, and combinations thereof.

[0032] Generally, when used, the concentration of each additive in the lubricating oil composition can range from about 0.001 wt% to about 10 wt%, from about 0.01 wt% to about 5 wt%, or from about 0.1 wt% to about 2.5 wt%, based on the total weight of the lubricating oil composition. Further, the total amount of additives in the lubricating oil composition can range from about 0.001 wt% to about 20 wt%, from about 0.01 wt% to about 10 wt%, or from about 0.1 wt% to about 5 wt%, based on the total weight of the lubricating oil composition.

[0033] In some embodiments, the electric driveline oil is substantially free of sulfur-containing zinc compounds, such as zinc dialkyldithiophosphates. In some embodiments, the sulfur-containing zinc compound is present in an amount that contributes 100 ppm or less zinc, based on the total weight of the electric driveline oil. In some embodiments, the electric driveline oil contains less than 100 ppm zinc, based on the total weight of the electric driveline oil.

[0034] Oil of lubricating viscosity The lubricating oil compositions disclosed herein generally include at least one oil of lubricating viscosity. Any base oil known to those skilled in the art can be used as the oil of lubricating viscosity disclosed herein. Some base oils suitable for use in making the lubricating oil compositions are described in Mortier et al., “Chemistry and Technology of Lubricants”, 2ndEdition, London, Springer, Chapters 1 and 2 (1996); and A. Sequeria, Jr., “Lubricant Base Oil and Wax Processing”, New York, Marcel Decker, Chapter 6, (1994); and D. V. Brock, Lubrication Engineering, Vol. 43, pp. 184-5, (1987), all of which are incorporated by reference herein. Generally, the amount of base oil in the lubricating oil composition can be from about 70 wt% to about 99.5 wt%, based on the total weight of the lubricating oil composition. In some embodiments, the amount of base oil in the lubricating oil composition is from about 75 wt% to about 99 wt%, from about 80 wt% to about 98.5 wt%, or from about 80 wt% to about 98 wt%, based on the total weight of the lubricating oil composition.

[0035] In certain embodiments, the base oil is or comprises any natural or synthetic lubricating base oil fraction. Some non-limiting examples of synthetic oils include oils made from the polymerization of at least one a-olefin, such as ethylene, or from hydrocarbon synthesis procedures using carbon monoxide and hydrogen, such as the Fisher-Tropsch process, such as polyalphaolefins or PAOs. In certain embodiments, the base oil comprises less than about 10 wt% of one or more heavy fractions, based on the total weight of the base oil. A heavy fraction refers to a lubricating oil fraction having a viscosity of at least about 20 cSt at 100 °C. In certain embodiments, the heavy fraction has a viscosity of at least about 25 cSt or at least about 30 cSt at 100 °C. In further embodiments, the amount of one or more heavy fractions in the base oil is less than about 10 wt%, less than about 5 wt%, less than about 2.5 wt%, less than about 1 wt%, or less than about 0.1 wt%, based on the total weight of the base oil. In other further embodiments, the base oil does not comprise a heavy fraction.

[0036] In certain embodiments, the lubricating oil composition comprises a major amount of a base oil of lubricating viscosity. In some embodiments, the base oil has a kinematic viscosity at 100 °C of about 2.5 centistokes (cSt) to about 20 cSt, about 4 centistokes (cSt) to about 20 cSt, or about 5 cSt to about 16 cSt. The kinematic viscosity of the base oil or lubricating oil composition disclosed herein can be measured according to ASTM D 445, which is incorporated herein by reference.

[0037] In other embodiments, the base oil is or comprises a base stock or a blend of base stocks. In further embodiments, the base stock is manufactured using various different methods, including but not limited to distillation, solvent refining, hydroprocessing, oligomerization, esterification, and rerefining. In some embodiments, the base stock comprises a rerefined stock. In further embodiments, the rerefined stock is substantially free of materials introduced by manufacturing, contamination, or prior use.

[0038] In some implementations, the base oil comprises one or more base oils from Groups I through V as defined in American Petroleum Institute (API) Publication 1509, Fourteenth Edition, December 1996 (i.e., API Base Oil Interchangeability Guidelines for Passenger Car Motor Oils and Diesel Engine Oils), which is incorporated herein by reference. The API guidelines define base oils as lubricant components that can be manufactured using various methods. Group I, II, and III base oils are mineral oils, each with a specific range of saturated mass, sulfur content, and viscosity index. Group IV base oils are polyalphaolefins (PAOs). Group V base oils include all other base oils not included in Groups I, II, III, or IV.

[0039] In some embodiments, the base oil comprises one or more base oils selected from Group I, Group II, Group III, Group IV, Group V, or combinations thereof. In other embodiments, the base oil comprises one or more base oils selected from Group II, Group III, Group IV, or combinations thereof. In still other embodiments, the base oil comprises one or more base oils selected from Group II, Group III, Group IV, or combinations thereof, wherein the base oil has a kinematic viscosity at 100°C of about 2.5 centiliters (cSt) to about 20 cSt, about 4 cSt to about 20 cSt, or about 5 cSt to about 16 cSt.

[0040] The base oil can be selected from the group consisting of natural oils having a lubricating viscosity, synthetic oils having a lubricating viscosity, and mixtures thereof. In some embodiments, the base oil includes base oil feedstocks obtained by isomerization of synthetic waxes and porous waxes, and hydrocracked base oil feedstocks produced by hydrocracking (rather than solvent extraction) the aromatic and polar components of crude oil. In other embodiments, the base oil having a lubricating viscosity includes natural oils such as animal oils, vegetable oils, mineral oils (e.g., liquid petroleum and solvent-treated or acid-treated paraffin, naphthenic, or mixed paraffin-naphthenic mineral oils), oils derived from coal or shale, and combinations thereof. Some non-limiting examples of animal oils include bone oil, lanolin, fish oil, lard, dolphin oil, seal oil, shark oil, tallow, and whale oil. Some non-limiting examples of vegetable oils include castor oil, olive oil, peanut oil, rapeseed oil, corn oil, sesame oil, cottonseed oil, soybean oil, sunflower oil, safflower oil, hemp oil, linseed oil, tung oil, Brazil nut oil, jojoba oil, and meadowfoam seed oil. These oils may be partially or fully hydrogenated.

[0041] In some embodiments, the synthetic oil having a lubricating viscosity includes hydrocarbon oils and halogen-substituted hydrocarbon oils, such as polymerized and interpolymerized olefins, alkylbenzenes, polybenzenes, alkylated diphenyl ethers, alkylated diphenyl sulfides, and their derivatives, analogs, and homologues. In other embodiments, the synthetic oil includes epoxy alkyl polymers, interpolymers, copolymers, and their derivatives, wherein the terminal hydroxyl groups may be modified by esterification, etherification, etc. In still other embodiments, the synthetic oil includes esters of dicarboxylic acids and various alcohols. In some embodiments, the synthetic oil includes C5 to C6... 12 Esters prepared from monocarboxylic acids, polyols, and polyol ethers. In another embodiment, the synthetic oil includes trialkyl phosphate oils, such as tributyl phosphate and triisobutyl phosphate.

[0042] In some embodiments, the synthetic oil having a lubricating viscosity includes silicone-based oils (such as polyalkyl-, polyaryl-, polyalkoxy-, polyaryloxy-siloxane oils, and silicate oils). In other embodiments, the synthetic oil includes phosphoric acid-containing liquid esters, polymeric tetrahydrofurans, polyalphaolefins, etc.

[0043] Base oils derived from wax hydroisomerization can be used alone or in combination with the aforementioned natural and / or synthetic base oils. These wax isomerized oils are produced by hydroisomerizing natural or synthetic waxes or mixtures thereof on a hydroisomerization catalyst.

[0044] In another embodiment, the base oil comprises a poly-α-olefin (PAO). Generally, poly-α-olefins can be derived from α-olefins having about 2 to about 30, about 4 to about 20, or about 6 to about 16 carbon atoms. Non-limiting examples of suitable poly-α-olefins include those derived from octene, decene, mixtures thereof, etc. These poly-α-olefins have viscosities at 100°C of about 2 centipoise to about 15 centipoise, about 3 centipoise to about 12 centipoise, or about 4 centipoise to about 8 centipoise. In some instances, poly-α-olefins can be used with other base oils, such as mineral oils.

[0045] In another embodiment, the base oil comprises a polyalkylene glycol or a polyalkylene glycol derivative, wherein the terminal hydroxyl groups of the polyalkylene glycol may be modified by esterification, etherification, acetylation, etc. Non-limiting examples of suitable polyalkylene glycols include polyethylene glycol, polypropylene glycol, polyisopropylene glycol, and combinations thereof. Non-limiting examples of suitable polyalkylene glycol derivatives include ethers of polyalkylene glycols (e.g., methyl ether of polyisopropylene glycol, diphenyl ether of polyethylene glycol, diethyl ether of polypropylene glycol, etc.), monocarboxylic acid esters and polycarboxylic acid esters of polyalkylene glycols, and combinations thereof. In some cases, polyalkylene glycols or polyalkylene glycol derivatives may be used in conjunction with other base oils, such as poly-α-olefins and mineral oils.

[0046] In another embodiment, the base oil comprises any one of the following esters of dicarboxylic acids (e.g., phthalic acid, succinic acid, alkyl succinic acid, alkenyl succinic acid, maleic acid, azelaic acid, octanoic acid, sebacic acid, fumaric acid, adipic acid, linoleic acid dimer, malonic acid, alkyl malonic acid, alkenyl malonic acid, etc.) and various alcohols (e.g., butanol, hexanol, dodecyl alcohol, 2-ethylhexanol, ethylene glycol, diethylene glycol monoether, propylene glycol, etc.). Non-limiting examples of these esters include dibutyl adipate, di(2-ethylhexyl) sebacate, di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl phthalate, di(eicosyl) sebacate, 2-ethylhexyl diester of linoleic acid dimer, etc.

[0047] In another embodiment, the base oil comprises hydrocarbons prepared via the Fischer-Tropsch process. The Fischer-Tropsch process uses a Fischer-Tropsch catalyst to produce hydrocarbons from a gas containing hydrogen and carbon monoxide. These hydrocarbons may require further processing to be usable as base oils. For example, methods known to those skilled in the art can be used to dewax, hydroisomerize, and / or hydrocracking the hydrocarbons.

[0048] In another embodiment, the base oil includes unrefined oil, refined oil, re-refined oil, or mixtures thereof. Unrefined oil is oil obtained directly from a natural or synthetic source without further purification. Non-limiting examples of unrefined oil include shale oil obtained directly from a dry distillation operation, petroleum obtained directly from primary distillation, and ester oil obtained directly from an esterification process and used without further processing. Refined oil is similar to unrefined oil, except that it has been further processed by one or more purification methods to improve one or more properties. Many such purification methods are known to those skilled in the art, such as solvent extraction, double distillation, acid or alkali extraction, filtration, percolation, etc. Re-refined oil is obtained by applying methods similar to those used to obtain refined oil to refined oil. Such re-refined oils are also called regenerated oils or reprocessed oils and are typically subjected to additional treatment by methods designed to remove waste additives and oil decomposition products.

[0049] The following embodiments are presented to illustrate implementation methods, but are not intended to limit this application to the specific embodiments described. Unless otherwise stated, all parts and percentages are by weight. All values ​​are approximate. When numerical ranges are given, it should be understood that implementations outside the stated ranges are still within the scope of this application. Specific details described in each embodiment should not be construed as essential features.

[0050] Examples The following examples are intended for illustrative purposes only and are not intended to limit the scope in any way.

[0051] The following performance tests were conducted on the oil sample of the present invention and the comparative oil sample.

[0052] Shell 4-ball wear test According to the 4-ball wear test ASTM D4172, the anti-wear properties of each lubricant composition were determined under the conditions of 1200 rpm, 60°C oil temperature, and a 40 kgf load for 60 minutes. After the test, the test balls were removed and the wear marks were measured. The wear mark diameters are reported in Table 1. A smaller wear mark diameter indicates better anti-wear performance.

[0053] High frequency reciprocating rig (HFRR) wear test The coefficient of friction is measured using a high-frequency reciprocating test chamber (HFRR). The test equipment and procedure are similar to the ASTM D6079 method, except that the test oil temperature is increased from 32°C to 110°C at a rate of 2°C / min, and a 500 g load is used with a frequency of 20 Hz for 1 hour. This test can measure the average coefficient of friction and wear volume.

[0054] ZF bearing fretting test Bearing performance was evaluated using the ZF Standard 03C bearing pitting test 0000 702 232. This test was conducted on an FE 8 roller thrust bearing with an axial force of 68 kN and a speed of 300 rpm. The temperature was 100°C. In this test, the duration of failure was measured, and a failure was defined as when vibration became so severe that metal fragments detached from the bearing or the housing in contact with it, and the FE8 test bench automatically shut down. The detached metal left pits in the bearing or housing. The minimum failure duration to pass the ZF 03C test is 300 hours. The maximum permissible test run time is 750 hours. ZF bearing pitting test equipment is available from Assmann Laboratories, Aachen, Germany.

[0055] Bearing performance is evaluated using the ZF Standard 03C bearing pitting test. In this test, the duration of failure is measured, and a failure is defined as when vibration becomes so severe that metal fragments detach from the bearing or the housing in contact with it, and the FE8 test bench automatically shuts down. The minimum failure duration for passing the test is 300 hours. The maximum permissible test run time is 750 hours. ZF bearing pitting test equipment is available from Assmann Laboratories, Aachen, Germany.

[0056] The compositions of Examples 1-5 were evaluated using the four-ball wear test and the HFRR wear test.

[0057] The results of the four-ball wear test and the HFRR wear test are summarized in Table 1 below.

[0058] Table 1 1

[0059] 1 60 mM HOB sulfonate, 0.1 wt% glycerol derivative, base oil 2 Average 4 balls: 40 kgf, 60℃, 1200 RPM, 60 minutes 3 Average HFRR: 60 min, 20 Hz, 1 mm, 110 °C, 500 g 4 EOT friction average value (lasting 15 minutes) Table 2 1

[0060] 5 bearing pitting, mean time to failure The composition of Example 6 was evaluated using the ZF bearing pitting test. The results of the ZF bearing test are summarized in Table 2 below. As shown in the table, Example 6 demonstrates the effectiveness of the glycerol derivative in the bearing pitting test.

[0061] As shown in Table 2, the pitting results of the ZF bearing in Example 6 (ZF FE8) demonstrate the effectiveness of the glycerol derivative in the bearing pitting test.

[0062] The compositions of Examples 7-9 were evaluated using a four-ball abrasion test. The results are summarized in Table 3 below.

[0063] Table 3

[0064] 6 Average 4 balls: 40 kgf, 60℃, 1200 RPM, 60 minutes 7 60 mM HOB sulfonate, 0.01 wt% glycerol derivative, base oil 8 60 mM HOB sulfonate, 0.05 wt% glycerol derivative, base oil As shown in Table 3, the four-ball milling results of Examples 7-9 demonstrate the anti-wear ability of low amounts (0.01-0.05 wt%) of nitrogen-containing additives.

[0065] It should be understood that various modifications can be made to the embodiments disclosed herein. Therefore, the foregoing description should not be construed as restrictive, but merely as examples of embodiments of the invention. For example, the functions described above and implemented for operational purposes are for illustrative purposes only. Other arrangements and methods can be implemented by those skilled in the art without departing from the scope and spirit of this application. Furthermore, other modifications will occur to those skilled in the art within the scope and spirit of the appended claims.

Claims

1. An electric driveline oil, the electric driveline oil comprising: (a) a major amount of an oil of lubricating viscosity; and (b) an electric driveline additive, the electric driveline additive including a nitrogen- or sulfur-containing additive or derivatives thereof; wherein the electric driveline additive in an amount of about 0.001 wt % to about 1.5 wt % based on the total weight of the electric driveline oil.

2. The electric driveline oil of claim 1, further comprising an overbased sulfonate detergent.

3. The electric driveline oil of claim 1, wherein the nitrogen- or sulfur-containing additive is an alkyl polyol.

4. The electric driveline oil of claim 1, wherein the derivatives thereof are cyclic derivatives.

5. The electric driveline oil of claim 1, wherein the electric driveline oil is substantially free of sulfur-containing zinc compounds.

6. The electric driveline oil of claim 1, wherein the electric driveline oil has less than 100 ppm of Zn.

7. The electric oil of claim 1, wherein the sulfur-containing compound is a thioglycerol, a thione, a thioether, a disulfide, or a polysulfide.

8. The electric oil of claim 1, wherein the nitrogen-containing compound is a polyol amine, a polyol amide, or a hydroxyl amino ether.

9. A method of improving wear, friction, or fatigue performance of an engine featuring an electric driveline, the method comprising lubricating the engine with an electric driveline oil, the electric driveline oil comprising: (a) a major amount of an oil of lubricating viscosity; and (b) an electric driveline additive, the electric driveline additive including a nitrogen- or sulfur-containing compound or derivatives thereof; wherein the electric driveline additive in an amount of about 0.001 wt % to about 1.5 wt % based on the total weight of the electric driveline oil.

10. The method of claim 9, wherein the electric driveline oil further comprises an overbased sulfonate detergent.

11. The method of claim 9, wherein the derivatives thereof are cyclic derivatives.

12. The method of claim 9, wherein the electric driveline oil is substantially free of sulfur-containing zinc compounds.

13. The method of claim 9, wherein the electric driveline oil has less than 100 ppm of Zn.

14. The method of claim 9, wherein the sulfur-containing compound is a thioglycerol, a thione, a thioether, a disulfide, or a polysulfide.

15. The method of claim 9, wherein the nitrogen-containing compound is a polyol amine, a polyol amide, or a hydroxyl amino ether.

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