Lubricants containing polyphosphate additives

Abstract

A lubricating oil composition is described. The composition comprises a majority of a base oil of lubricating viscosity and a polyphosphate-based dispersion. The dispersion includes ammonium polyphosphate and a dispersant.

Description

[Technical field]

[0001] The present disclosure relates to a lubricating oil additive composition and a lubricating oil composition comprising the lubricating oil additive composition. More specifically, the present invention provides a polyphosphate-based antiwear agent having reduced ash production levels. [Background technology]

[0002] Traditional anti-wear additives (such as zinc dithiophosphates) are often used in lubricants to reduce the risk of metal-to-metal contact in engines, but engine combustion in the presence of metal-containing lubricant additives can produce ash.

[0003] Ash buildup causes many well-known problems, including clogging of engine particulate filters resulting in reduced fuel economy and other adverse effects. It would therefore be desirable to provide new lubricating oil additives that are ashless or produce less ash than conventional lubricating oil additives. Summary of the Invention

[0004] In one aspect, a lubricating oil composition is provided that comprises a majority of a base oil of lubricating viscosity and a polyphosphate-based dispersion comprising ammonium polyphosphate and a dispersant.

[0005] In another aspect, a lubricating oil composition is provided that includes a majority amount of a base oil of lubricating viscosity, ammonium polyphosphate, and a dispersant.

[0006] In a further aspect, there is provided a method of operating an internal combustion engine comprising lubricating the engine with a lubricating oil comprising a majority amount of a base oil of lubricating viscosity, ammonium polyphosphate, and a dispersant. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Introduction In this specification, the following words and expressions, if used, have the meanings set out below.

[0008] The term "oil-soluble" means that for a particular additive, the amount required to provide the desired level of activity or performance can be added by dissolving, dispersing or suspending in an oil of lubricating viscosity. Typically, this means that at least 0.001 wt.% of the additive can be added to a lubricating oil composition. The term "fuel-soluble" is a similar expression that describes an additive that is dissolved, dispersed or suspended in a fuel.

[0009] By "minor amount" is meant less than about 50% by weight of the composition, expressed relative to the listed additive, calculated as the active ingredient of the additive, and expressed relative to the total weight in the composition.

[0010] By "major amount" is meant greater than about 50% by weight of the composition, expressed relative to the listed additive, calculated as the active ingredient of the additive, and expressed relative to the total weight in the composition.

[0011] An "engine" or "combustion engine" is a heat engine in which the combustion of a fuel occurs in a combustion chamber. An "internal combustion engine" is a heat engine in which the combustion of a fuel occurs in an enclosed space (the "combustion chamber"). A "spark ignition engine" is a heat engine in which the combustion is ignited by a spark, usually from a spark plug. This is in contrast to a "compression ignition engine", usually a diesel engine, in which the heat generated by the injection and compression of the fuel is sufficient to initiate combustion without an external spark.

[0012] The present invention provides a lubricating oil composition comprising a majority of a base oil of lubricating viscosity and a polyphosphate antiwear agent. Polyphosphate is not easily dissolved in oil due to its highly polar structure. Therefore, the present invention further provides a dispersant to which the polyphosphate antiwear agent is added to form a polyphosphate-based dispersion in oil. In general, the effectiveness of the polyphosphate-based dispersion depends on the uniformity of the dispersion in the lubricating oil fluid. The uniformity of the dispersion can be correlated with the turbidity of the polyphosphate-based dispersion.

[0013] Polyphosphate-Based Dispersions The polyphosphate-based dispersion of the present invention comprises ammonium polyphosphate and a dispersant. In some embodiments, the polyphosphate dispersion can be metal-free (i.e., less than about 2 ppm of the total lubricating oil composition), substantially metal-free (i.e., less than about 50 ppm of the total lubricating oil composition), zinc-free (i.e., less than about 2 ppm of the total lubricating oil composition), or substantially zinc-free (i.e., less than about 50 ppm of the total lubricating oil composition). As a result, the polyphosphate-based dispersion of the present invention is ash-free ("ashless") or has reduced ash content compared to metal-based antiwear agents.

[0014] In some embodiments, the polyphosphate-based dispersions can be used in combination with metal-based antiwear agents, such as zinc dithiophosphate (ZnDTP), hi some embodiments, the zinc dithiophosphate is present at about 0.01% to 15% by weight.

[0015] According to one embodiment, the ammonium polyphosphate has the following generalized structure I: [ka] wherein R is independently hydrogen or a hydrocarbyl group, n is an integer ranging from 1 to 1000, and m is n+2.

[0016] Since ammonium polyphosphate is generally insoluble in the medium of lubricating oil, it is effective to add the polyphosphate as a dispersion in the oil by mixing it in a dispersant.

[0017] The dispersant may be any molecule capable of dispersing or distributing ammonium polyphosphate in the lubricating oil composition. Dispersants are typically long amphiphilic molecules with both hydrophilic and hydrophobic ends. Dispersants are capable of forming flocculating structures, such as emulsions, in the lubricating oil composition.

[0018] The amount of dispersant used is usually the minimum amount that gives a stable dispersion. In particular, metal dispersants (such as metal detergents) can lead to ash formation. These dispersants should not exceed about 6% of the total volume of the ingredients. The total amount of surfactants should not exceed about 20% of the total volume of the ingredients.

[0019] Dispersing agents compatible with the present invention include known organic surfactants such as stearates, benzenesulfonates, phosphatidylcholines, alkenyl succinates, oleates, fatty alcohols, alkenyl succinimides, and the like.

[0020] The polyphosphate-based dispersions of the present invention can be prepared by any suitable means. The following describes a method for obtaining the dispersion by dehydrating an aqueous solution of ammonium hydroxide and phosphoric acid, or a water-in-oil emulsion of an aqueous solution of ammonium phosphate. Ideally, a solution is prepared in which the charge molar ratio of ammonium hydroxide to phosphoric acid is 1:1.

[0021] This solution is then added to a combination of neutral oil, dispersant, and optionally detergent, and mixed in a high shear mixer (e.g., blender) to form an emulsion. The resulting emulsion is heated (140°C) to partially dehydrate it. During dehydration of the emulsion, water is rapidly removed at 104°C to 108°C.

[0022] After this point, nearly all of the process water has been removed. The additional water removed after this stage is believed to be dehydration of the hydrated phosphate oligomers. The cloudy emulsion begins to clear at 110-120°C, then becomes cloudy again at 130-140°C. At this point the product has reached the desired level of dehydration and heating should be stopped immediately.

[0023] The cooled product reverts to a clear homogeneous mixture at room temperature containing approximately 6.5% by weight phosphorus from the dispersed ammonium polyphosphate.

[0024] lubricating oil composition The polyphosphate dispersants of the present disclosure are useful as dispersant additives in lubricating oils. The concentration of the dispersion of the present disclosure in the lubricating oil composition may be in the range of 0.01 to 15% by weight (e.g., 0.1 to 10% by weight, 0.2 to 5.0% by weight, 0.5 to 2.0% by weight) based on the total weight of the lubricating oil composition.

[0025] An oil of lubricating viscosity (sometimes referred to as a "base stock" or "base oil") is the primary liquid component of a lubricant into which additives and possibly other oils are blended to provide, for example, the final lubricant (i.e., lubricant composition). Base oils are useful for preparing concentrates and lubricating oil compositions therefrom, and can be selected from natural (vegetable, animal, or mineral) and synthetic lubricating oils, and mixtures thereof.

[0026] The definitions of base stocks and base oils in this disclosure are the same as those set forth in American Petroleum Institute (API) Publication 1509 Annex E ("API Base Oil Interchangeability Guidelines for Passenger Car Motor Oils and Diesel Engine Oils," December 2016). Group I base stocks contain less than 90% saturates and / or more than 0.03% sulfur and have a viscosity index of 80 or greater and less than 120 using the test methods specified in Table E-1. Group II base stocks contain 90% or greater saturates, 0.03% or less sulfur, and have a viscosity index of 80 or greater and less than 120 using the test methods specified in Table E-1. Group III base stocks contain 90% or greater saturates, 0.03% or less sulfur, and have a viscosity index of 120 or greater using the test methods specified in Table E-1. Group IV base stocks are polyalphaolefins (PAOs). Group V base stocks include all other base stocks not included in Groups I, II, III, or IV.

[0027] Natural oils include animal oils, vegetable oils (e.g., castor oil and lard oil), and mineral oils. Animal and vegetable oils with favorable thermo-oxidative stability can be used. Of the natural oils, mineral oils are preferred. Mineral oils vary widely with respect to their crude source, for example, whether they are paraffinic, naphthenic, or mixed paraffinic-naphthenic. Oils derived from coal or shale are also useful base oils. Natural oils also vary by the methods used in their production and refinement, for example, their distillation range, and whether they are straight run or cracked, hydrorefined, or solvent extracted.

[0028] Synthetic oils include hydrocarbon oils. Hydrocarbon oils include oils such as polymerized and copolymerized olefins (e.g., polybutylene, polypropylene, propylene isobutylene copolymers, ethylene-olefin copolymers, and ethylene-alpha olefin copolymers). Polyalphaolefin (PAO) oil base stocks are widely used synthetic hydrocarbon oils. Examples include C8-C 14 Olefins, e.g., C8, C 10 , C 12 , C 14 PAOs derived from olefins, or mixtures thereof, can also be used.

[0029] Other useful fluids for use as base oils include non-conventional or unconventional base stocks, preferably catalytically treated or synthetically processed to impart high performance properties.

[0030] Unconventional or unconventional base stocks / base oils include one or more of a mixture of base stock(s) derived from one or more Gas-to-Liquids (GTL) materials, as well as isomerized / isodewaxed base stock(s) derived from natural wax or waxy feedstocks, mineral and / or non-mineral oil waxy feedstocks such as slack wax, natural wax, and non-petroleum derived waxy materials such as gas oil, waxy fuels hydrocracker residual oil, waxy raffinate, hydrocrackate, pyrolysate, or other mineral, mineral oil, or even waxy materials received from coal liquids or shale oil, as well as mixtures of such base stocks.

[0031] The base oils for use in the lubricating oil compositions of the present disclosure can be any of the API Group I, Group II, Group III, Group IV and Group V oils, and mixtures thereof, preferably API Group II, Group III, Group IV and Group V oils, and mixtures thereof, more preferably the various oils corresponding to Group III through Group V base oils because of their superior volatility, stability, viscometric and cleanliness properties.

[0032] Generally, the base oil is 2.5 to 20 mm 2 / sec (e.g., 3 to 12 mm 2 / sec, 4~10mm 2 / sec, or 4.5-8mm 2 The kinematic viscosity (ASTM D445) at 100° C. is in the range of 1 / sec.

[0033] The lubricating oil composition can also include conventional lubricant additives to provide auxiliary functions, resulting in a finished lubricating oil composition in which these additives are dispersed or dissolved.For example, the lubricating oil composition can be blended with antioxidants, ashless dispersants, antiwear agents, detergents such as metal detergents, rust inhibitors, anti-foam agents, demulsifiers, friction modifiers, metal deactivators, pour point depressants, viscosity modifiers, antifoam agents, co-solvents, package compatibility agents, corrosion inhibitors, pigments, extreme pressure agents, etc., and mixtures thereof.Various additives are known and commercially available.These additives, or their analogous compounds, can be used to prepare the lubricating oil composition of the present invention by conventional blending procedures.

[0034] Each of the above additives, when used, is used in a functionally effective amount to impart the desired properties to the lubricant. Thus, for example, if the additive is an ashless dispersant, a functionally effective amount of the ashless dispersant is an amount sufficient to impart the desired dispersant properties to the lubricant. In general, the concentration of each of these additives when used can range from about 0.001 to about 20% by weight, for example, from about 0.01 to about 10% by weight, unless otherwise specified.

[0035] The following illustrative examples are intended to be non-limiting. EXAMPLES

[0036] Polyphosphate dispersion 1 A dispersion containing ammonium polyphosphate was prepared by dehydrating an oil-in-water emulsion of an aqueous ammonium phosphate solution by heating to 139° C. for 1.5 hours.

[0037] The aqueous solution was prepared in a 2 liter glass beaker by stirring and heating a mixture of 510.8 g DI water and 250.8 g ammonium phosphate to 80° C. until the ammonium phosphate was completely dissolved.

[0038] An oil-in-water emulsion was prepared by slowly adding the water phase to an oil phase containing 540.3 g of Exxon 150 neutral oil, 120.54 g of an alkenyl succinate salt having a molecular weight of approximately 1100 amu, and 51.26 g of a neutral sulfonate salt.

[0039] The solution was vigorously mixed using a high shear mixer while the aqueous phase was slowly added to form a cloudy emulsion, which was then partially dehydrated in a 4 L beaker equipped with a mechanical stirrer, a temperature controlled hot plate, and a nitrogen inlet.

[0040] Polyphosphate dispersion 2 The dispersed polyphosphate component was prepared according to the procedure described for Polyphosphate Dispersion 1, except that equimolar amounts of phosphoric acid and ammonium hydroxide were used instead of the ammonium phosphate solution.

[0041] Polyphosphate Dispersion 3 A dispersed polyphosphate component was prepared following the steps described for Polyphosphate Dispersion 1, except that the neutral sulfonate was omitted. This example contained 4.26% phosphorus. The TBN was 128 mg KOH / g.

[0042] Polyphosphate Dispersion 4 The dispersed polyphosphate component was prepared according to the procedure described in Polyphosphate Dispersion 1, except that 2-ethylhexanol was added instead of the neutral sulfonate.

[0043] Polyphosphate Dispersions 1-4 all exhibited NTU (nephelometric turbidity units) below 100, indicating that stable suspensions were formed.

[0044] These polyphosphate dispersions were added to Group II paraffinic base oil at various treat rates to prepare the comparative and example examples summarized in Table 1.

[0045] Comparative Example 1 is a Group II paraffinic base oil containing no antiwear additives.

[0046] Comparative Example 2 is a Group II paraffinic base oil containing 1 wt. % of a commercial secondary zinc dialkyldithiophosphate.

[0047] Example 1A is a Group II paraffinic base oil containing 0.125 wt. % Polyphosphate Dispersion 1.

[0048] Example 1B is a Group II paraffinic base oil containing 0.25 wt. % Polyphosphate Dispersion 1.

[0049] Example 1C is a Group II paraffinic base oil containing 0.5 wt. % Polyphosphate Dispersion 1.

[0050] Example 1D is a Group II paraffinic base oil containing 1.0 wt. % Polyphosphate Dispersion 1.

[0051] Example 2 is a Group II paraffinic base neutral oil containing 1.0 wt. % Polyphosphate Dispersion 2.

[0052] Example 3 is a Group II paraffinic base neutral oil containing 1.0 wt. % Polyphosphate Dispersion 3.

[0053] Ex 4 is a Group II paraffinic base oil containing 1.0 wt % Polyphosphate Dispersion 4.

[0054] Electrical Contact Resistance (ECR) Measurement by MTM Comparative Examples 1 and 2 and Examples 1-4 were evaluated using a Mini Traction Machine (MTM) tribometer from PCS Instruments Ltd., London, UK. The MTM tribometer was set up to operate in pin-on-disc mode using an abrasive disc made from 52100 steel from PCS Instruments and a 0.25 inch fixed ball bearing, also made from 52100 steel from Falex corporation, in place of the pin. Testing was carried out at 100°C, 7 Newton load, and sliding speed of 200 mm / sec for 40 minutes, followed by a break-in period of 5 minutes at 0.1 Newton load and sliding speed of 2000 mm / sec.

[0055] The formation of a wear-preventing lubricant film can be measured by electrical contact resistance (ECR). ECR (Electrical Contact Resistance) is an add-on to the standard MTM system. The electrical resistance is measured between the disk and the upper specimen (ball, pin or roller).

[0056] An electrical potential is applied to the ball. When the upper specimen is completely separated from the lower specimen (disc), the ECR reading is 100%. Direct metal-to-metal contact between the specimens results in a short circuit and an ECR reading of 0%. A reading of 100% indicates that a completely insulating oil film has formed. The maximum ECR values ​​and the time required to reach 100% ECR (indicating the formation of a lubricating oil film) are also shown in Table 1.

[0057] Comparative Example 1, which contains no additive, was unable to reach 100% ECR. Similarly, Example 1A, which contains a very low dosage of ammonium polyphosphate dispersion, was unable to reach 100% ECR. Examples 1B-1D and Examples 2-4 all reached 100% ECR within a relatively short time frame, and Examples 1D and 2 in particular showed comparable film formation A performance to Comparative Example 2, which contains the same dosage of commercial ZnDTP antiwear additive. [Table 1]

[0058] Baseline Formulation A A baseline formulation A was prepared by blending the following components together to obtain a lubricant formulation of SAE 5W-30 viscosity grade: (a) a mixture of borated succinimide dispersants and non-borated succinimide dispersants; (b) magnesium sulfonate surfactant; (c) calcium phenates and calcium sulfonates; (d) alkylated diphenylamine and hindered phenol antioxidants; (e) molybdenum succinimide antioxidants; (f) conventional amounts of pour point depressants, viscosity index improvers, and foam suppressants, and (g) The balance is a blend of Group II base oils.

[0059] Comparative Example 3 Comparative Example 3 was formulated using baseline Formulation A with the addition of 1.03 wt. % of a commercially available zinc secondary dialkyldithiophosphate (ZnDTP).

[0060] Example 5 Example 5 was formulated using baseline formulation A with the addition of 0.77 wt % of the commercial secondary ZnDTP and 0.31 wt % of the ammonium polyphosphate dispersion of Example 1.

[0061] Example 6 Example 6 was formulated using baseline formulation A with the addition of 0.52 wt % of the commercial secondary ZnDTP and 0.625 wt % of the ammonium polyphosphate dispersion of Example 1.

[0062] Example 7 Example 7 was formulated using baseline formulation A with the addition of 0.26 wt % of the commercial secondary ZnDTP and 0.94 wt % of the ammonium polyphosphate dispersion of Example 1.

[0063] Example 8 Example 8 was formulated using baseline Formulation A with the addition of 1.25% by weight of the ammonium polyphosphate dispersion of Example 1.

[0064] Mini Traction Machine (MTM) Evaluation The lubricating oil compositions of Comparative Example 3 and Examples 5-8 were evaluated using a Mini Traction Machine (MTM) tribometer from PCS Instruments Ltd. (London, UK). The MTM tribometer was set up to operate in pin-on-disc mode using an abrasive disc made of 52100 steel from PCS Instruments and a 0.25 inch fixed ball bearing, also made of 52100 steel from Falex corporation, in place of the pin. Testing was carried out at 100°C, 7 Newton load, and sliding speed of 200 mm / s for 40 minutes, followed by a break-in period of 5 minutes at 0.1 Newton load and sliding speed of 2000 mm / s. The test results in Table 2 show the wear scars generated on the ball bearings as measured by optical microscopy using conventional methods. The average wear scar from four test runs is shown. [Table 2]

[0065] As shown in Table 2 above, at the same phosphorus-based treat rate, Examples 5-8 containing ashless ammonium polyphosphate dispersions exhibit superior antiwear performance compared to Comparative Example 3 containing the conventional ZnDTP additive. More importantly, Examples 5-8 contain lower levels of sulfated ash than Comparative Example 3. Example 8 does not contain zinc and therefore has a reduced sulfated ash concentration compared to Comparative Example 3.

[0066] Baseline Formulation B A baseline formulation B was prepared by blending the following components together to obtain a lubricant formulation of SAE 5W-30 viscosity grade: (a) a succinimide dispersant, (b) calcium phenates and calcium sulfonates; (c) alkylated diphenylamine antioxidants; (d) conventional amounts of pour point depressants, viscosity index improvers, and foam suppressors; and (e) The balance being a blend of Group III base oils.

[0067] Comparative Example 4 Comparative Example 4 was formulated using baseline Formulation B which contained no zinc dialkyldithiophosphate (ZnDTP).

[0068] Comparative Example 5 A lubricant formulation was formed containing the same additives, base oil, and treat rate as baseline formulation B with the addition of 0.17 wt. % of a secondary zinc dialkyldithiophosphate.

[0069] Comparative Example 6 A lubricant formulation was formed containing the same additives, base oil, and treat rate as baseline formulation B with the addition of 0.43 wt. % secondary zinc dialkyldithiophosphate.

[0070] Example 9 A lubricant formulation was formed containing the same additives, base oil, and treat levels as Baseline Formulation B with 0.47 wt % of the ammonium polyphosphate dispersion of Example 1 added.

[0071] Sequence IVA Screener Exam Comparative Examples 4-6 and Example 9 were evaluated for valve train wear in a modified version of the Sequence IVA test (ASTM D 6891).

[0072] The Modified Sequence IVA Screener test evaluates a lubricant's ability to prevent camshaft lobe wear in overhead camshaft engines. More specifically, the test measures the ability of a crankcase oil to control camshaft lobe wear in spark ignition engines with overhead valve trains and sliding cam followers. The test is designed to simulate service in taxis, light delivery trucks, and commuter vehicles.

[0073] The Sequence IVA Screener test method is a 50 hour test with two sets of 25 hour cycles, one run for 25 hours at 40°C followed by 25 hours at 100°C. Unleaded fuel "Haltermann KA24E Green" is used. The test rig is a KA24E Nissan 2.4 liter, water-cooled, fuel injected engine, 4 cylinder in-line, overhead camshaft, with two intake valves and one exhaust valve per cylinder.

[0074] The average cam wear values ​​(average (μm) at seven positions) are shown in Table 3 below. [Table 3]

[0075] Comparative Example 4 does not contain any anti-wear additive and shows high average cam wear. Comparative Examples 5 and 6 show low cam wear but high sulfated ash levels with ZnDTP. In contrast, Example 9 shows not only superior anti-wear performance for a formulation containing ZnDTP, but also low ash levels.

[0076] Unless inconsistent with the present text, all documents described herein, including any priority documents and / or test procedures, are incorporated herein by reference. As is apparent from the above general description and specific embodiments, various forms of the present disclosure have been illustrated and described, but various modifications can be made without departing from the spirit and scope of the present disclosure. Accordingly, the present disclosure is not intended to be limited thereby.

[0077] Similarly, the term "comprising" is considered synonymous with the term "comprising." Similarly, whenever a composition, element, or group of elements is preceded by the transitional phrase "comprising," it also contemplates the same composition or group of elements being preceded by the transitional phrase "consisting essentially of," "consisting of," "selected from the group of consisting of," or "is," and vice versa.

[0078] As used herein, the terms "a" and "the" are understood to encompass the plural as well as the singular.

[0079] Various terms have been defined above. Unless a term used in the claims is defined above, it should be given the broadest definition that one of ordinary skill in the relevant art would give that term, as reflected in at least one printed publication or issued patent. Furthermore, all patents, test methods, and other documents cited in this application are incorporated by reference in their entirety to the extent such disclosure is not inconsistent with this application and in all jurisdictions where such incorporation is permitted.

[0080] The above description of the disclosure illustrates and describes the disclosure. Moreover, while only preferred embodiments are shown and described in the disclosure, it should be understood that the disclosure can be used in various other combinations, modifications, and environments, as described above, and that changes or modifications can be made within the scope of the concepts expressed herein, equivalent to the teachings above and / or the skill or knowledge of the relevant art. While the above relates to embodiments of the disclosure, other and further embodiments of the disclosure can be devised without departing from the basic scope thereof, which scope is determined by the claims.

[0081] The above-described embodiments are intended to further illustrate the best known modes for carrying out the invention, and to enable others skilled in the art to utilize the present disclosure in such or other embodiments with various modifications as may be required for a particular application or use. Therefore, the above description is not intended to limit the invention to the forms disclosed herein. It is intended that the appended claims be construed to include alternative embodiments.

Claims

1. 1. A lubricating oil composition comprising: a majority amount of a base oil of lubricating viscosity; a polyphosphate-based dispersion comprising ammonium polyphosphate and a dispersing agent; The ammonium polyphosphate has the following structure: 【Chemical 1】 wherein R is independently hydrogen or a hydrocarbyl group, n is an integer ranging from 1 to 1000, and m is n+2.

2. 10. The lubricating oil composition of claim 1, wherein the dispersant is a surfactant.

3. 2. The lubricating oil composition of claim 1, wherein the dispersant is a stearate, a benzenesulfonate, a phosphatidylcholine, an alkenyl succinate, an oleate, or a fatty alcohol.

4. 10. The lubricating oil composition of claim 1, further comprising an antioxidant, dispersant, antiwear agent, detergent, rust inhibitor, dehaze agent, demulsifier, friction modifier, metal deactivator, pour point depressant, viscosity modifier, antifoam agent, cosolvent, package compatibility agent, corrosion inhibitor, dye, or extreme pressure additive.

5. 10. The lubricating oil composition of claim 1, further comprising a zinc dithiophosphate.

6. 1. A lubricating oil composition comprising: a majority amount of a base oil of lubricating viscosity; ammonium polyphosphate, a dispersant, The ammonium polyphosphate has the following structure: 【Chemistry 2】 wherein R is independently hydrogen or a hydrocarbyl group, n is an integer ranging from 1 to 1000, and m is n+2.

7. 7. The lubricating oil composition of claim 6, wherein the dispersant is a surfactant.

8. 7. The lubricating oil composition of claim 6, wherein the dispersant is a stearate, a benzenesulfonate, a phosphatidylcholine, an alkenyl succinate, an oleate, or a fatty alcohol.

9. 7. The lubricating oil composition of claim 6, further comprising an antioxidant, dispersant, antiwear agent, detergent, rust inhibitor, dehaze agent, demulsifier, friction modifier, metal deactivator, pour point depressant, viscosity modifier, antifoam agent, cosolvent, package compatibility agent, corrosion inhibitor, pigment, or extreme pressure additive.

10. The lubricating oil composition of claim 6, further comprising a zinc dithiophosphate.

11. 1. A method of operating an internal combustion engine, comprising: below: a majority amount of a base oil of lubricating viscosity; ammonium polyphosphate, lubricating the engine with a lubricating oil comprising a dispersant; The ammonium polyphosphate has the following structure: 【Chemistry 3】 wherein R is independently hydrogen or a hydrocarbyl group, n is an integer ranging from 1 to 1000, and m is n+2.

12. The method of claim 11 , wherein the dispersant is a surfactant.

13. 12. The method of claim 11, wherein the dispersing agent is a stearate, a benzenesulfonate, a phosphatidylcholine, an alkenyl succinate, an oleate, or a fatty alcohol.

14. 12. The method of claim 11, wherein the lubricating oil composition further comprises an antioxidant, a dispersant, an antiwear agent, a detergent, a rust inhibitor, a dehaze agent, a demulsifier, a friction modifier, a metal deactivator, a pour point depressant, a viscosity modifier, an antifoam agent, a cosolvent, a package compatibility agent, a corrosion inhibitor, a pigment, or an extreme pressure additive.

15. 12. The method of claim 11, wherein the lubricating oil further comprises a zinc dithiophosphate.

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