Nitrogen and sulfur-containing additives in fluids for electric vehicles

Abstract

The electric driveline fluid is described. The fluid comprises an oil of a major lubricating viscosity and an electric driveline additive. The electric driveline additive includes a nitrogen or sulfur-containing additive or a derivative thereof. The amount of the electric driveline additive is approximately 0.001% to approximately 1.5% by weight, based on the total weight of the electric driveline fluid.

Description

Technical Field

[0001] The present disclosure relates to a lubricant additive composition and a lubricating oil composition containing the same. More specifically, the composition provides improved protection against wear, friction, and / or fatigue in electric vehicles.

Background Art

[0002] Wear, friction, and / or fatigue can be major problems for conventional internal combustion engines. The same can also be a major problem in automobiles that utilize electric motors relying on planetary gears (e.g., electric vehicles or hybrid vehicles). Different from conventional automobiles, electric vehicles and / or hybrid vehicles present some unique challenges, especially because often the same lubricating fluid is shared by the electric motor and the transmission.

Summary of the Invention

[0003] In one aspect, the present disclosure relates to an electric driveline fluid, the electric driveline fluid 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 a derivative thereof, the amount of the electric driveline additive being from about 0.001 wt% to about 1.5 wt% based on the total weight of the electric driveline fluid.

[0004] In another aspect, the present disclosure relates to a method of improving the wear, friction or fatigue performance of an engine equipped with an electric driveline, the method comprising lubricating the engine with an electric driveline fluid, the electric driveline fluid 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 a derivative thereof, the amount of the electric driveline additive being from about 0.001 wt% to about 1.5 wt% based on the total weight of the electric driveline fluid.

Modes for Carrying Out the Invention

[0005] Definitions The following terms are used throughout this specification and, unless otherwise indicated, have the following meanings:

[0006] The term “major amount” of base oil refers to an amount of base oil that is at least 40% by weight of the lubricating oil composition. In some embodiments, “major amount” of base oil refers to an amount of base oil that is more than 50% by weight, more than 60% by weight, more than 70% by weight, more than 80% by weight, or more than 90% by weight of the lubricating oil composition.

[0007] "HOB" refers to high overbasicity with a TBN of over 250 based on the active substance, while "LOB" refers to low overbasicity with a TBN of less than 100 based on the active substance.

[0008] The term "Total Base Number," or "TBN," refers to the level of alkalinity in an oil sample that indicates the composition's ability to continue neutralizing corrosive acids, according to ASTM standard number D2896 or an equivalent procedure. This test measures the change in conductivity and expresses the result as mgKOH / g (the equivalent number of milligrams of KOH required to neutralize 1 gram of the product). Therefore, a high TBN reflects that the product is strongly overbasic, and consequently indicates a large reserve of base for neutralizing acids.

[0009] As used herein, EV fluid refers to the electric drive fluid used in electric vehicles equipped with a wet EV motor. Electric drive fluid is similar to transmission fluid (used in conventional vehicles) but typically has one or more additional functions (e.g., acting as a coolant for the EV motor and providing electrical resistance). One or more additional functions can present unique challenges in formulating EV fluids.

[0010] This application relates to a nitrogen or sulfur-containing additive and / or a lubricating oil composition (e.g., an electric driveline fluid) containing the same. This composition(s) is suitable for use in automobiles including electric drivelines (i.e., automobiles equipped with electric motors). 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 driveline additive) and a highly overbasic sulfonate detergent. As an advantage, the composition exhibits enhanced protection against fatigue, wear, and / or friction.

[0011] In some additional embodiments, the lubricating oil compositions of the present invention can provide protection against fatigue, wear, and / or friction in hybrid vehicles or plug-in hybrid vehicles equipped with electric motors.

[0012] Nitrogen or sulfur-containing additives The lubricating oil compositions of this disclosure include an electric driveline additive comprising 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 or fewer carbon atoms, such as 24 or fewer carbon atoms, 23 or fewer carbon atoms, 22 or fewer carbon atoms, 21 or fewer carbon atoms, 20 or fewer carbon atoms, 19 or fewer carbon atoms, 18 or fewer carbon atoms, 17 or fewer carbon atoms, or 16 or fewer carbon atoms.

[0013] In some embodiments, the nitrogen-containing additive includes polyolamines, polyolamides, or hydroxyaminoethers.

[0014] Polyolamine In some embodiments, the electric driveline additive comprises a polyolamine, which has at least two hydroxyl groups.

[0015] In some embodiments, the polyolamine has the following generalized structure: [ka] In the formula, X, Y, and Z are independently an amine, an alcohol, a hydrocarbylamine, or a hydrocarbyl alcohol group, where at least two of X, Y, and Z are alcohols or hydrocarbyl alcohol groups, and at least one of X, Y, and Z is an amine or a hydrocarbylamine. As described above, the total number of carbon atoms in the polyolamine is 25 or less.

[0016] Specific examples of polyolamines include, for example, 3-aminopropane-1,2-diol (structure A1), 2-aminopropane-1,3-diol (structure A2), and 3-(dimethylamino)propane-1,2-diol (structure A3). In some embodiments, the polyolamine comprises at least one 1,2-diol moiety (e.g., structure A1). In some embodiments, the polyolamine comprises at least one 1,3-diol moiety (e.g., structure A2). [ka]

[0017] Polyolamide In some embodiments, the electric driveline additive includes a polyolamide. The polyolamide may have the following generalized structure B: [ka] In the formula, each R is independently either H or a hydrocarbyl group having 20 or fewer carbon atoms.

[0018] Specific polyol amides include, for example, 2,3-dihydroxypropanamide (Structure B1), N-ethyl-2,3-dihydroxypropanamide (Structure B2), 2,3-dihydroxy-N-isopropylpropanamide (Structure B3), and N,N-diethyl-2,3-dihydroxypropanamide (Structure B4).

Chem.

[0019] Hydroxyamino ether In some embodiments, the electric drive line additive includes a hydroxyamino ether. The hydroxyamino ether can have the following generalized structure:

Chem.

[0020] Specific hydroxyamino ethers include, for example, 2-(2-aminoethoxy)ethan-1-ol (Structure C1) and 2-(2-(2-aminoethoxy)ethoxy)ethan-1-ol (Structure C2).

Chem.

[0021] Sulfur-containing polyol Specific examples of sulfur-containing polyols include thioglycerol (structure D1), thion (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 structures D3 or D4, x is an integer from 1 to 10. R is a hydrocarbyl group having 22 or fewer carbon atoms. [ka]

[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, cyclic derivatives have 5-membered, 6-membered, 7-membered, or 8-membered rings. Specific examples of cyclic derivatives include, for example, 2-methyl-1,3-dioxolan-4-amine (structure E1), 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-thion (structure E5). [ka]

[0023] While not limited to theory, the chirality of one or more carbon atoms in each additive compound is thought to significantly influence its performance.

[0024] The exact amount of electric driveline additive may vary depending on the specific composition and amount or lubricating viscosity of the oil, the specific detergent and amount, and other desired properties of the lubricating oil composition. In some embodiments, the amount of electric driveline additive is from at least about 0.001, or at least about 0.05, or at least about 0.1, or at least about 0.3, or at least about 0.4, or at least about 0.4, or at least about 0.5, or at least about 0.75, or at least about 1.0% by weight, up to about 1.5, or up to about 1.25, or up to about 1.0, or up to about 0.9, or up to about 0.8% by weight, based on the total weight of the lubricating oil composition.

[0025] Cleansing agent In some embodiments, the lubricating oil composition contains a metal sulfonate detergent. The metal can be any metal suitable for the manufacture of the 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, etc.

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

[0027] Optionally, the lubricating oil composition may contain additional detergents commonly known in the art. Several suitable detergents are described in Mortier et al., “Chemistry and Technology of Lubricants,” 2nd Edition, 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), both of which are incorporated herein by reference. Examples of these detergents include phenates, salicylates, and phosphonates.

[0028] In some embodiments, the cleaning agent comprises at least one highly overbasic (TBN greater than 250 on an active substance basis) sulfonate cleaning agent, such as highly overbasic calcium sulfonate.

[0029] Overbasic metal detergents are generally produced by carbonating a mixture of hydrocarbons, a cleansing acid (e.g., sulfonic acid, alkyl hydroxybenzoate, etc.), a metal oxide or hydroxide (e.g., calcium oxide or calcium hydroxide), and an accelerator (e.g., xylene, methanol, and water). For example, when preparing overbasic calcium sulfonate, in carbonation, calcium oxide or calcium hydroxide reacts with gaseous carbon dioxide to form calcium carbonate. The sulfonic acid is neutralized with excess CaO or Ca(OH)2 to form a sulfonate.

[0030] Generally speaking, an overbasic detergent may be a low-overbasic (LOB) overbasic salt, for example, an overbasic salt with a TBN of less than 100 based on the active substance. In one embodiment, the TBN of a low-overbasic salt may be about 10 to about 100. In another embodiment, the TBN of a low-overbasic salt may be about 10 to about 80. An overbasic detergent may be a moderately overbasic (MOB) overbasic salt, for example, an overbasic salt with a TBN of about 100 to about 250 based on the active substance. In one embodiment, the TBN of a moderately overbasic salt may be about 100 to about 200. In another embodiment, the TBN of a moderately overbasic salt may be about 125 to about 175. An overbasic detergent may be a high-overbasic (HOB) overbasic salt, for example, an overbasic salt with a TBN greater than 250 based on the active substance. In one embodiment, the TBN of a high-overbasic salt may be about 250 to about 800 based on the active substance.

[0031] Other additives Optionally, the lubricating oil composition may further contain at least additives or modifiers (hereinafter referred to as "additives") that can impart or improve any desired properties of the lubricating oil composition. Any additive known to those skilled in the art can be used in the lubricating oil compositions disclosed herein. Several suitable additives are described in Mortier et al., “Chemistry and Technology of Lubricants,” 2nd Edition. London, Springer, (1996); and Leslie R. Rudnick, “Lubricant Additives: Chemistry and Applications,” New York, Marcel Dekker (2003), both of which are incorporated herein by reference. In some embodiments, the additives can be selected from the group consisting of antioxidants, wear inhibitors, cleaning agents, rust inhibitors, anti-emulsifiers, friction modifiers, multifunctional additives, viscosity index improvers, pour point depressants, foam inhibitors, metal deactivators, dispersants, corrosion inhibitors, lubricity improvers, thermal stability improvers, anti-fogging additives, anti-icing agents, dyes, markers, antistatic agents, biocides, and combinations thereof.

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

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

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

[0035] In certain embodiments, the base oil is or contains any natural or synthetic lubricating base oil fraction. Some non-limiting examples of synthetic oils include oils such as polyalphaolefins or PAOs prepared from the polymerization of at least one alpha-olefin, such as ethylene, or from hydrocarbon synthesis procedures using carbon monoxide and hydrogen gas, such as the Fischer-Tropsch process. In certain embodiments, the base oil contains one or more heavy fractions in less than about 10% by weight, 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% by weight, less than about 5% by weight, less than about 2.5% by weight, less than about 1% by weight, or less than about 0.1% by weight, based on the total weight of the base oil. In further embodiments, the base oil does not contain any heavy fractions.

[0036] In certain embodiments, the lubricating oil composition comprises a base oil with a primary lubricating viscosity. In some embodiments, the base oil has a kinematic viscosity 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 at 100°C. The kinematic viscosity of the base oils or lubricating oil compositions 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 produced using a variety of different processes, including but not limited to extraction, solvent purification, hydrogenation, oligomerization, esterification, and repurification. In some embodiments, the base stock comprises repurified stock. In further embodiments, the repurified stock is substantially free of substances introduced by manufacture, contamination, or prior use.

[0038] In some embodiments, the base oil comprises one or more base stocks from groups I to V as specified in American Petroleum Institute (API) Publication 1509, Fourteen Edition, December 1996 (i.e., API Base Oil Interchangeability Guidelines for Passenger Car Motor Oils and Diesel Engine Oils) (incorporated herein by reference). The API guidelines define base stock as a lubricant component that can be produced using a variety of different processes. Group I, II, and III base stocks are mineral oils, each having a specific range of saturated mass, sulfur content, and viscosity index. Group IV base stocks are polyalphaolefins (PAOs). Group V base stocks comprise all other base stocks not included in groups I, II, III, or IV.

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

[0040] The base oil can be selected from the group consisting of natural oils of lubricating viscosity, synthetic oils of lubricating viscosity, and mixtures thereof. In some embodiments, the base oil includes base stocks obtained by isomerization of synthetic waxes and slack waxes, as well as hydrocracking base stocks produced by hydrocracking (rather than solvent extraction) the aromatic and polar components of crude oil. In other embodiments, the base oil of lubricating viscosity includes natural oils, e.g., animal oils, vegetable oils, mineral oils (e.g., liquid petroleum and paraffinic, naphthenic, or mixed paraffin-naphthenic solvent-treated or acid-treated mineral oils), coal or shale-derived oils, and combinations thereof. Some non-limiting examples of animal oils include bone oil, lanolin, fish oil, lard, dolphin oil, seal oil, shark oil, tallow oil, and whale oil. Some non-exclusive 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, oyster oil, jojoba oil, and meadowfoam oil. Such oils may be partially or fully hydrogenated.

[0041] In some embodiments, synthetic oils of lubricating viscosity include hydrocarbon oils and halo-substituted hydrocarbon oils, such as polymerized and copolymerized olefins, alkylbenzenes, polyphenyls, alkylated diphenyl ethers, alkylated diphenyl sulfides, and their derivatives, analogs, and homologs. In other embodiments, synthetic oils include alkylene oxide polymers, interpolymers, copolymers, and their derivatives, where terminal hydroxyl groups can be modified by esterification, etherification, etc. In further embodiments, synthetic oils include esters of dicarboxylic acids and various alcohols. In specific embodiments, synthetic oils include C5-C 12 Examples include monocarboxylic acids and esters produced from polyols and polyol ethers. In further embodiments, examples of synthetic oils include trialkyl phosphate oils such as tri-n-butyl phosphate and tri-iso-butyl phosphate.

[0042] In some embodiments, examples of synthetic oils with lubricating viscosity include silicone-based oils (such as polyalkyl-, polyaryl-, polyalkoxy-, polyaryloxysiloxane oils, and silicate oils). In other embodiments, examples of synthetic oils include liquid esters of phosphorus-containing acids, high molecular weight tetrahydrofurans, and polyalphaolefins.

[0043] Base oils derived from the hydrogen isomerization of waxes may also be used alone or in combination with the aforementioned natural and / or synthetic base oils. Such wax isomerized oils are produced by hydrogen isomerizing natural or synthetic waxes or mixtures thereof on a hydrogen isomerization catalyst.

[0044] In further embodiments, the base oil comprises poly-alpha-olefins (PAOs). Generally, poly-alpha-olefins can be derived from alpha-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-alpha-olefins include those derived from octene, decene, or mixtures thereof. These poly-alpha-olefins may have viscosities of about 2 to about 15, about 3 to about 12, or about 4 to about 8 centistokes at 100°C. In some cases, poly-alpha-olefins can be used with other base oils, such as mineral oils.

[0045] In further embodiments, the base oil comprises a polyalkylene glycol or a polyalkylene glycol derivative, where 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, the polyalkylene glycol or polyalkylene glycol derivative may be used with other base oils such as poly-alpha-olefins and mineral oil.

[0046] In further embodiments, the base oil includes any esters of dicarboxylic acids (e.g., phthalic acid, succinic acid, alkyl succinic acid, alkenyl succinic acid, maleic acid, azelaic acid, suberic acid, sebacic acid, fumaric acid, adipic acid, linoleic acid dimer, malonic acid, alkyl malonic acid, alkenyl malonic acid, etc.) and various alcohols (e.g., butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, 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 azelaate, diisodecyl azelaate, dioctyl phthalate, didecyl phthalate, dieicosyl sebacate, and 2-ethylhexyl diester of linoleic acid dimer.

[0047] In further embodiments, the base oil comprises hydrocarbons prepared by the Fischer-Tropsch process. The Fischer-Tropsch process uses a Fischer-Tropsch catalyst to prepare hydrocarbons from a gas containing hydrogen and carbon monoxide. Further processing may be required to make these hydrocarbons useful as base oils. For example, the hydrocarbons can be dewaxed, hydrogen-isomerized, and / or hydrocrackened using methods known to those skilled in the art.

[0048] In further embodiments, the base oil includes unrefined oil, refined oil, refined oil, or mixtures thereof. Unrefined oil is oil obtained directly from a natural or synthetic source without further refining. 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 the former is further processed by one or more refining processes to improve one or more properties. Many such refining processes are known to those skilled in the art, such as solvent extraction, secondary distillation, acid or base extraction, filtration, and leaching. Refined oil is obtained by applying a process similar to that used to obtain refined oil to refined oil. Such refined oil is also known as recycled oil or reprocessed oil and is often further processed by processes aimed at removing spent additives and oil decomposition products.

[0049] The following embodiments are presented to illustrate the embodiments, but are not intended to limit this application to the specific embodiments described. Unless otherwise indicated, all parts and percentages are by weight. All numerical values ​​are approximate. Where a numerical range is given, it should be understood that embodiments outside that range may still be included within the scope of this application. Specific details described in each embodiment should not be construed as essential features. [Examples]

[0050] The following examples are for illustrative purposes only and are not intended to limit the scope of the subject.

[0051] The oil sample of the invention and the comparative oil sample were subjected to the following performance tests.

[0052] Shell 4-ball abrasion test The wear resistance of each lubricating oil composition was determined according to the ASTM D4172 four-ball wear mark test under conditions of 1200 rpm, an oil temperature of 60°C, and a load of 40 kgf 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. Smaller wear mark diameters indicate better wear resistance.

[0053] High-frequency reciprocating rig (HFRR) wear test The coefficient of friction was measured by a high-frequency reciprocating rig (HFRR) test. The test apparatus and procedure were the same as those of ASTM D6079, except that the temperature of the test oil was raised from 32°C to 110°C for 1 hour at a rate of 2°C / min, a 500g load, and a frequency of 20Hz. This test can measure the average coefficient of friction and the amount of wear.

[0054] ZF bearing pitting test Bearing performance is evaluated using the ZF Specification 03C bearing pitting test 0000 702 232. This test uses an FE 8 thrust roller bearing with an axial force of 68 kN and a rotational speed of 300 rpm. The temperature is 100°C. The test measures the time to failure; failure is determined when vibrations become severe and a metal fragment detaches from the bearing or the case it contacts, at which point the FE8 test apparatus automatically stops. The removed metal leaves a pit inside the bearing or case. To pass the ZF 03C specification test, the minimum time to failure is 300 hours. The maximum test duration is 750 hours. The ZF bearing pitting test is available from Assmann Laboratories, Aachen, Germany.

[0055] The bearing performance is evaluated using the ZF Specification 03C bearing pitting test. This test measures the time to failure; failure is determined when vibrations become severe and metal fragments detach from the bearing or its contact case, at which point the FE8 test apparatus automatically shuts down. The minimum time to failure required to pass the test is 300 hours. The maximum test duration is 750 hours. The ZF bearing pitting test is available from Assmann Laboratories, Aachen, Germany.

[0056] The compositions of Examples 1 to 5 were evaluated using the four-ball and HFRR abrasion tests.

[0057] The results of the ball-strike and HFRR wear tests are summarized in Table 1 below. [Table 1] [Table 2]

[0058] 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, Example 6 demonstrates the effectiveness of the glycerol derivative in the bearing pitting test.

[0059] As shown in Table 2, the ZF bearing pitting results (ZF FE8) for Example 6 demonstrate the effectiveness of the glycerol derivative in passing the bearing pitting test.

[0060] The compositions of Examples 7-9 were evaluated using a four-ball abrasion test. The results are summarized in Table 3 below. [Table 3]

[0061] As shown in Table 3, the four-ball abrasion results for Examples 7-9 demonstrate the abrasion resistance of nitrogen-containing additives at low concentrations (0.01-0.05 wt%).

[0062] It will be understood that various modifications can be made to the embodiments disclosed herein. Therefore, the above description should not be construed as limiting, but merely as illustrative examples of embodiments of the present invention. For example, the functions described above and implemented for operation are for illustrative purposes only. Those skilled in the art will be able to implement other configurations and methods without departing from the scope and spirit of this application. Furthermore, those skilled in the art will be able to conceive of other modifications within the scope and spirit of the claims appended herein.

Claims

1. Electric drive line fluid, (a) A main amount of oil with lubricating viscosity, (b) an electric driveline additive containing a nitrogen or sulfur-containing additive or a derivative thereof, The amount of the electric driveline additive is approximately 0.001% by weight to approximately 1.5% by weight, based on the total weight of the electric driveline fluid. The aforementioned electric drive line fluid.

2. The electric driveline fluid according to claim 1, further comprising a perbasic sulfonate cleaning agent.

3. The electric drive line fluid according to claim 1, wherein the nitrogen or sulfur-containing additive is an alkyl polyol.

4. The electric drive line fluid according to claim 1, wherein the derivative is a cyclic derivative.

5. The electric drive line fluid according to claim 1, wherein the electric drive line fluid substantially does not contain a sulfur-containing zinc compound.

6. The electric drive line fluid according to claim 1, wherein the electric drive line fluid has less than 100 ppm of Zn.

7. The electrofluid according to claim 1, wherein the sulfur-containing compound is thioglycerol, thion, thioether, disulfide, or polysulfide.

8. The electrofluid according to claim 1, wherein the nitrogen-containing compound is a polyolamine, polyolamide, or hydroxyaminoether.

9. A method for improving the wear, friction, or fatigue performance of an engine equipped with an electric driveline, the method comprising lubricating the engine with an electric driveline fluid, the electric driveline fluid being (a) A main amount of oil with lubricating viscosity, (b) an electric driveline additive comprising a nitrogen or sulfur-containing compound or a derivative thereof, The amount of the electric driveline additive is approximately 0.001% by weight to approximately 1.5% by weight, based on the total weight of the electric driveline fluid. The aforementioned method.

10. The method according to claim 9, wherein the electric drive line fluid further comprises a perbasic sulfonate cleaning agent.

11. The method according to claim 9, wherein the derivative is a cyclic derivative.

12. The method according to claim 9, wherein the electric driveline fluid substantially does not contain a sulfur-containing zinc compound.

13. The method according to claim 9, wherein the electric drive line fluid has less than 100 ppm of Zn.

14. The method according to claim 9, wherein the sulfur-containing compound is thioglycerol, thion, thioether, disulfide, or polysulfide.

15. The method according to claim 9, wherein the nitrogen-containing compound is a polyolamine, a polyolamide, or a hydroxyaminoether.

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