Composition and method for preventing or reducing low-speed pre-ignition in direct injection spark ignition engine

Abstract

To provide a lubricating engine oil composition comprising, as major components, a lubricating oil base and at least one metal or semi-metal hydrogen atom donor compound.SOLUTION: Disclosed are a method for preventing or reducing low-speed pre-ignition in a direct injection boosted spark ignition internal combustion engine, and the use of at least one metal or semi-metal hydrogen atom donor compound in a lubricating engine oil composition for preventing or reducing low-speed pre-ignition in a direct injection boosted spark ignition internal combustion engine.SELECTED DRAWING: None

Description

[Technical field]

[0001] FIELD OF THEINVENTION The present disclosure relates to a lubricant composition containing at least one metal hydride compound.The present disclosure also relates to a lubricant composition containing at least one metal or metalloid hydrogen atom donor compound for direct injection boost spark ignition internal combustion engines.The present disclosure also relates to a method for preventing or reducing low speed pre-ignition in engines lubricated with formulated oils.The formulated oils have a composition comprising at least one oil-soluble or oil-dispersible metal or metalloid hydrogen atom donor compound. [Background technology]

[0002] 2. Background of the Invention In recent years, engine manufacturers have developed smaller (downsized) engines that offer higher power density and better performance while reducing friction and pumping losses. This is accomplished by increasing boost pressure using turbochargers or mechanical superchargers, and by slowing the engine down using higher transmission gear ratios, allowing it to produce higher torque at lower engine speeds. However, it has been found that providing higher torque at lower engine speeds can cause random pre-ignition of the engine at low speeds (a phenomenon known as "low speed pre-ignition" or "LSPI"), resulting in extremely high cylinder peak pressures that can lead to catastrophic engine failure. The possibility of LSPI prevents engine manufacturers from fully optimizing engine torque at low engine speeds in such small, high-power engines.

[0003] One of the leading theories regarding the cause of low speed pre-ignition (LSPI) is that it is due, at least in part, to spontaneous ignition of engine oil droplets that enter the engine combustion chamber under high pressure through the piston crevice when the engine is running at low speed and the compression stroke is at its longest (Amann et al. SAE 2012-01-1140).

[0004] Although some engine knock and pre-ignition problems can be solved by using new engine technologies such as electronic controls and knock sensors, and by optimizing engine operating conditions, there is a need for lubricating oil compositions that can reduce or prevent LSPI problems and also improve or maintain other performance such as wear and oxidation protection. Summary of the Invention [Problem to be solved by the invention]

[0005] The present inventors have discovered a solution to address the problem of LSPI by using metal hydride compounds. [Means for solving the problem]

[0006] Summary of the Invention A lubricating engine oil composition for use in a miniature boosted engine is disclosed which comprises a base stock as a major component and one or more of silicon hydrides, germanium hydrides, and tin hydrides as minor components, the miniature engine being in the range of 0.5 liters to 3.6 liters.

[0007] Also disclosed is a method for preventing or reducing low speed pre-ignition in a direct injection boosted spark ignition internal combustion engine, the method comprising the step of lubricating a crankcase of the engine with a lubricating oil composition comprising from about 25 to about 3000 ppm of a metal or metalloid hydrogen atom donor derived from one or more silicon hydrides, germanium hydrides, and tin hydrides, based on the total weight of the lubricating oil composition.

[0008] Further disclosed is the use of one or more of silicon hydrides, germanium hydrides, and tin hydrides in a lubricating engine oil composition to prevent or reduce low speed pre-ignition in a direct injection boosted spark ignition internal combustion engine. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Detailed Description of the Invention The term "boosting" is used throughout this specification. Boosting refers to running an engine at a higher intake pressure than a naturally aspirated engine. A boosted condition can be achieved by using a turbocharger (exhaust driven) or a supercharger (engine driven). "Boosting" allows engine manufacturers to use smaller engines, providing higher power density while reducing friction and pumping losses, providing superior performance.

[0010] Throughout this specification and claims, the expression oil-soluble or dispersible is used. Oil-soluble or dispersible means that the amount required to provide the desired level of activity or performance can be incorporated by dissolving, dispersing or suspending in oil of lubricating viscosity. Typically, this means that at least about 0.001% by weight of the material can be incorporated into the lubricating oil composition. For further discussion of oil-solubility and dispersibility, particularly the term "stably dispersible", see U.S. Pat. No. 4,320,019 (expressly incorporated herein by reference for the relevant teachings in this regard).

[0011] The term "sulfated ash" as used herein refers to non-combustible residues resulting from detergents and metal additives in lubricating oils. Sulfated ash may be determined using ASTM test D874. The term "total base number" or "TBN" as used herein refers to the amount of base equivalent to the milligrams of KOH in one gram of sample. Thus, a higher TBN number reflects more alkaline products and therefore stronger alkalinity. TBN was determined using ASTM D 2896 test.

[0012] Unless otherwise specified, all percentages are by weight.

[0013] Typically, the level of sulfur in the lubricating oil composition of the present invention is about 0.7 wt% or less, e.g., about 0.01 wt% to about 0.70 wt%, 0.01 wt% to about 0.6 wt%, 0.01 wt% to about 0.5 wt%, 0.01 wt% to about 0.4 wt%, 0.01 wt% to about 0.3 wt%, 0.01 wt% to about 0.2 wt%, 0.01 wt% to about 0.10 wt% sulfur, based on the total weight of the lubricating oil composition. In one embodiment, the level of sulfur in the lubricating oil composition of the present invention is about 0.60 wt% or less, about 0.50 wt% or less, about 0.40 wt% or less, about 0.30 wt% or less, about 0.20 wt% or less, or about 0.10 wt% or less, based on the total weight of the lubricating oil composition.

[0014] In one embodiment, the level of phosphorus in the lubricating oil composition of the present invention is about 0.12 wt.% or less, e.g., about 0.01 wt.% to about 0.12 wt.% phosphorus, based on the total weight of the lubricating oil composition. In one embodiment, the level of phosphorus in the lubricating oil composition of the present invention is about 0.11 wt.% or less, e.g., about 0.01 wt.% to about 0.11 wt.% phosphorus, based on the total weight of the lubricating oil composition. In one embodiment, the level of phosphorus in the lubricating oil composition of the present invention is about 0.10 wt.% or less, e.g., about 0.01 wt.% to about 0.10 wt.% phosphorus, based on the total weight of the lubricating oil composition. In one embodiment, the level of phosphorus in the lubricating oil composition of the present invention is about 0.09 wt.% or less, e.g., about 0.01 wt.% to about 0.09 wt.% phosphorus, based on the total weight of the lubricating oil composition. In one embodiment, the level of phosphorus in the lubricating oil composition of the present invention is about 0.08 wt.% or less, e.g., from about 0.01 wt.% to about 0.08 wt.% phosphorus based on the total weight of the lubricating oil composition. In one embodiment, the level of phosphorus in the lubricating oil composition of the present invention is about 0.07 wt.% or less, e.g., from about 0.01 wt.% to about 0.07 wt.% phosphorus based on the total weight of the lubricating oil composition. In one embodiment, the level of phosphorus in the lubricating oil composition of the present invention is about 0.05 wt.% or less, e.g., from about 0.01 wt.% to about 0.05 wt.% phosphorus based on the total weight of the lubricating oil composition.

[0015] In one embodiment, the sulfated ash level produced by the lubricating oil composition of the present invention is about 1.60 wt% or less, as determined by ASTM D 874, such as from about 0.10 to about 1.60 wt% sulfated ash, as determined by ASTM D 874. In one embodiment, the sulfated ash level produced by the lubricating oil composition of the present invention is about 1.00 wt% or less, as determined by ASTM D 874, such as from about 0.10 to about 1.00 wt% sulfated ash, as determined by ASTM D 874. In one embodiment, the sulfated ash level produced by the lubricating oil composition of the present invention is about 0.80 wt% or less, as determined by ASTM D 874, such as from about 0.10 to about 0.80 wt% sulfated ash, as determined by ASTM D 874. In one embodiment, the sulfated ash level produced by the lubricating oil composition of the present invention is less than or equal to about 0.60 wt. % as determined by ASTM D 874, for example, a sulfated ash level of from about 0.10 to about 0.60 wt. % as determined by ASTM D 874.

[0016] Suitably, the lubricating oil composition may have a total base number (TBN) of from 4 to 15 mg KOH / g (e.g., from 5 to 12 mg KOH / g, from 6 to 12 mg KOH / g, or from 8 to 12 mg KOH / g).

[0017] Low speed pre-ignition is most likely to occur in direct injection boosted (turbocharged or supercharged) spark ignition (gasoline) internal combustion engines that generate, during operation, a brake mean effective pressure level of more than about 15 bar (peak torque) (at least about 18 bar, particularly at engine speeds of about 1500 to about 2500 revolutions per minute (rpm), e.g., at least about 20 bar at engine speeds of about 1500 to about 2000 rpm). As used herein, brake mean effective pressure (BMEP) is defined as the work accomplished during one engine cycle divided by engine displacement, engine torque normalized by engine displacement. The word "brake" refers to the actual torque / power available at the engine flywheel, as measured by a dynamometer. Thus, BMEP is a measure of the useful power of the engine.

[0018] In one embodiment of the invention, the engine operates at a speed between 500 rpm and 3000 rpm, or between 800 rpm and 2800 rpm, or between 1000 rpm and 2600 rpm. Further, the engine may operate at a brake mean effective pressure between 10 bar and 30 bar, or between 12 bar and 24 bar.

[0019] Although LSPI events are relatively rare, they can be catastrophic in nature. Thus, it is desirable to significantly reduce or even eliminate LSPI events during normal or sustained operation of a direct fuel injection engine. In one embodiment, the method of the present invention is such that there are less than 150 LSPI events / million combustion cycles (which can also be expressed as 15 LSPI events / 100,000 combustion cycles), or less than 100 LSPI events / million combustion cycles, or less than 70 LSPI events / million combustion cycles, or less than 60 LSPI events / million combustion cycles, or less than 50 LSPI events / million combustion cycles, or less than 40 LSPI events / million combustion cycles, or less than 30 LSPI events / million combustion cycles, or less than 20 LSPI events / million combustion cycles, or less than 10 LSPI events / million combustion cycles, or there may be 0 LSPI events / million combustion cycles.

[0020] Thus, in one aspect, the present disclosure provides a method for preventing or reducing low speed pre-ignition in a direct injection boosted spark ignition internal combustion engine, the method comprising lubricating a crankcase of the engine with a lubricating oil composition comprising at least one metal hydride compound. In one embodiment, the amount of metal from the at least one metal hydride is in the lubricating oil composition from about 100 to about 3000 ppm, from about 200 to about 3000 ppm, from about 250 to about 2500 ppm, from about 300 to about 2500 ppm, from about 350 to about 2500 ppm, from about 400 ppm to about 2500 ppm, from about 500 to about 2500 ppm, from about 600 to about 2500 ppm, from about 700 to about 2500 ppm, from about 700 to about 2000 ppm, or from about 700 to about 1500 ppm. In one embodiment, the amount of metal from the metal or metalloid hydrogen atom donor compound is about 2000 ppm or less, or 1500 ppm or less in the lubricating oil composition.

[0021] In one embodiment, the method of the present invention provides a reduction in the number of LSPI events of at least 10 percent, or at least 20 percent, or at least 30 percent, or at least 50 percent, or at least 60 percent, or at least 70 percent, or at least 80 percent, or at least 90 percent, or at least 95 percent compared to an oil that does not contain at least one metal hydride compound.

[0022] In another aspect, the present disclosure provides a method for reducing the severity of low speed pre-ignition events in a direct injection boosted spark ignition internal combustion engine, the method comprising lubricating a crankcase of the engine with a lubricating oil composition comprising at least one metal hydride compound. An LSPI event is determined by monitoring the peak cylinder pressure (PP) and 2% mass fraction burn (MFB02) crank angle of the fuel charge in the cylinder. When both criteria are met, an LSPI event is said to have occurred. The peak cylinder pressure threshold varies by test, but is typically 4-5 standard deviations above the mean cylinder pressure. Similarly, the MFB02 crank angle threshold is typically 4-5 standard deviations earlier than the mean MFB02 crank angle. LSPI events can be reported as average events per test, events per 100,000 combustion cycles, events per cycle, and / or combustion cycles per event. In one embodiment, the number of LSPI events is less than 15 events, less than 14 events, less than 13 events, less than 12 events, less than 11 events, less than 10 events, less than 9 events, less than 8 events, less than 7 events, less than 6 events, less than 5 events, less than 4 events, less than 3 events, less than 2 events, or less than 1 event per 100,000 combustion cycles when both MFB02 and peak pressure (PP) requirements were at pressures above 90 bar. In one embodiment, the number of LSPI events that were above 90 bar was 0 events. In other words, LSPI events above 90 bar were completely suppressed. In one embodiment, the number of LSPI events is less than 15 events, less than 14 events, less than 13 events, less than 12 events, less than 11 events, less than 10 events, less than 9 events, less than 8 events, less than 7 events, less than 6 events, less than 5 events, less than 4 events, less than 3 events, less than 2 events, or less than 1 event per 100,000 combustion cycles when both MFB02 and peak pressure (PP) requirements were at pressures above 100 bar. In one embodiment, the number of LSPI events that were above 100 bar was 0 events. In other words, LSPI events above 100 bar were completely suppressed.In one embodiment, the number of LSPI events is less than 15 events, less than 14 events, less than 13 events, less than 12 events, less than 11 events, less than 10 events, less than 9 events, less than 8 events, less than 7 events, less than 6 events, less than 5 events, less than 4 events, less than 3 events, less than 2 events, or less than 1 event per 100,000 combustion cycles when both MFB02 and peak pressure (PP) requirements were at pressures above 110 bar. In one embodiment, the number of LSPI events that were above 110 bar was 0 events. In other words, LSPI events above 110 bar were completely suppressed. For example, the number of LSPI events is less than 15 events, less than 14 events, less than 13 events, less than 12 events, less than 11 events, less than 10 events, less than 9 events, less than 8 events, less than 7 events, less than 6 events, less than 5 events, less than 4 events, less than 3 events, less than 2 events, or less than 1 event per 100,000 combustion cycles when both MFB02 and peak pressure (PP) requirements are at pressures above 120 bar. In one embodiment, the number of LSPI events that were above 120 bar was 0 events. In other words, very serious LSPI events (i.e., events above 120 bar) were completely suppressed.

[0023] It has now been found that the occurrence of LSPI in engines prone to LSPI can be reduced by lubricating such engines with a lubricating oil composition that includes a metal hydride compound.

[0024] The present disclosure further provides a method as described herein, wherein the engine is fueled with a liquid hydrocarbon fuel, a liquid non-hydrocarbon fuel, or a mixture thereof.

[0025] Lubricating oil compositions suitable for use as passenger car motor oils conventionally comprise a major amount of oil of lubricating viscosity, including ash-containing compounds, and minor amounts of performance-enhancing additives. Advantageously, the metals described herein are introduced into the lubricating oil compositions and used in the practice of the present disclosure by way of one or more metal or metalloid hydrogen atom donor compounds.

[0026] Oil / base oil composition of lubricating viscosity The oil of lubricating viscosity for use in the lubricating oil composition of the present disclosure, also referred to as base oil, is typically present in a major amount (e.g., greater than 50 wt%, preferably greater than about 70 wt%, more preferably about 80 wt% to about 99.5 wt%, and most preferably about 85 wt% to about 98 wt%) based on the total weight of the composition. As used herein, the expression "base oil" should be understood to mean a base oil or blend of base oils that are lubricant components manufactured to the same specifications by a single manufacturer (regardless of source or place of manufacturer), meet the same manufacturer's specifications, and are identified by a unique formulation, product identification number, or both. As used herein, a base oil may be any and all oils of lubricating viscosity now known or later discovered that are used in formulating lubricating oil compositions for such applications, such as engine oils, marine cylinder oils, functional fluids (e.g., hydraulic oils, gear oils, transmission fluids), and the like. Additionally, the base oils used herein may optionally contain viscosity index improvers, such as alkyl methacrylate polymers, olefin-based copolymers (e.g., ethylene-propylene or styrene-diene copolymers), and the like, and mixtures thereof.

[0027] As one skilled in the art will readily appreciate, the viscosity of the base oil will depend on the application. Thus, as used herein, the viscosity of the base oil will typically range from about 2 to about 2000 centistokes (cST) at 100° C. Generally, base oils used as engine oils will have kinematic viscosity ranges of about 2 cST to about 30 cST, preferably about 3 cST to about 16 cST, and most preferably about 4 cST to about 12 cST at 100° C., and may be selected or blended to produce the desired grade of engine oil (e.g., 0W, 0W-4, 0W-8, 0W-9, 0W-10, 0W-11, 0W-12, 0W-13, 0W-14, 0W-15, 0W-16, 0W-17, 0W-18, 0W-19, 0W-20, 0W-21, 0W-22, 0W-23, 0W-24, 0W-25, 0W-26, 0W-27, 0W-28, 0W-29 ... Lubricating oil compositions having SAE viscosity grades of 12, 0W-16, 0W-20, 0W-26, 0W-30, 0W-40, 0W-50, 0W-60, 5W, 5W-20, 5W-30, 5W-40, 5W-50, 5W-60, 10W, 10W-20, 10W-30, 10W-40, 10W-50, 15W, 15W-20, 15W-30, 15W-40, 30, 40, etc., are obtained.

[0028] Group I base oil generally refers to petroleum-derived lubricating base oils having a saturates content of less than 90 weight percent (as measured by ASTM D 2007) and / or a total sulfur content of more than 300 ppm (as measured by ASTM D 2622, ASTM D 4294, ASTM D 4297, or ASTM D 3120) and having a viscosity index (VI) of greater than or equal to 80 and less than 120 (as measured by ASTM D 2270).

[0029] Group II base oil generally refers to petroleum-derived lubricating base oils having a total sulfur content of 300 parts per million (ppm) or less (as determined by ASTM D 2622, ASTM D 4294, ASTM D 4927, or ASTM D 3120), a saturates content of 90 weight percent or more (as determined by ASTM D 2007), and a viscosity index (VI) between 80 and 120 (as determined by ASTM D 2270).

[0030] Group III base oil generally refers to petroleum derived lubricating base oils having less than 300 ppm sulfur, a saturates content greater than 90 wt. %, and a VI of 120 or greater.

[0031] Group IV base oils are polyalphaolefins (PAOs).

[0032] Group V base oils include all other base oils not included in Groups I, II, III, or IV.

[0033] The lubricating oil composition may contain minor amounts of other base oil components. For example, the lubricating oil composition may contain minor amounts of base oils derived from natural lubricating oils, synthetic lubricating oils, or mixtures thereof. Suitable base oils include base oils obtained by isomerization of synthetic wax and slack wax, and hydrocracked base oils produced by hydrocracking aromatic and polar components (not solvent extraction) of crude oil. Suitable natural oils include mineral lubricating oils (e.g., liquid petroleum), solvent- or acid-treated mineral lubricating oils that are paraffinic, naphthenic, or mixed paraffinic-naphthenic, oils derived from coal or shale, animal oils, vegetable oils (e.g., rapeseed oil, castor oil, and lard oil), and the like.

[0034] Suitable synthetic lubricating oils include, but are not limited to, hydrocarbon oils and halo-substituted hydrocarbon oils, such as polymerized and copolymerized olefins (e.g., polybutylene, polypropylene, propylene-isobutylene copolymers, chlorinated polybutylene, poly(1-hexene), poly(1-octene), poly(1-decene), and the like, and mixtures thereof), alkylbenzenes (e.g., dodecylbenzene, tetradecylbenzene, dinonylbenzene, di(2-ethylhexyl)-benzene, and the like), polyphenyls (e.g., biphenyl, terphenyl, alkylated polyphenyls, and the like), alkylated diphenyl ethers and alkylated diphenyl sulfides, and derivatives, analogs, and homologs thereof.

[0035] Other synthetic lubricating oils include, but are not limited to, oils made by polymerizing olefins having less than 5 carbon atoms, such as ethylene, propylene, butylene, isobutene, pentene, and mixtures thereof. Methods for preparing such polymeric oils are well known to those skilled in the art.

[0036] Further synthetic hydrocarbon oils include liquid polymers of alpha olefins having suitable viscosity. Particularly useful synthetic hydrocarbon oils are, for example, C6-C8 polymers such as 1-decene trimer. 12 It is a hydrogenated liquid oligomer of alpha olefins.

[0037] Another class of synthetic lubricating oils includes, but is not limited to, alkylene oxide polymers, i.e., homopolymers, interpolymers, and derivatives thereof, in which the terminal hydroxyl groups have been modified, for example, by esterification or etherification. These oils include oils prepared by the polymerization of ethylene oxide or propylene oxide, the alkyl and phenyl ethers of these polyoxyalkylene polymers (e.g., methyl polypropylene glycol ether having an average molecular weight of 1,000, diphenyl ether of polyethylene glycol having a molecular weight of 500-1000, diethyl ether of polypropylene glycol having a molecular weight of 1,000-1,500, etc.), or their mono- and polycarboxylic acid esters (e.g., acetate esters, mixed C3-C8 fatty acid esters, or C6-C8 fatty acid esters of tetraethylene glycol, etc.). 13 oxo acid diesters, etc.

[0038] Yet another class of synthetic lubricating oils includes, but is not limited to, the esters of dicarboxylic acids (e.g., phthalic acid, succinic acid, alkyl succinic acids, alkenyl succinic acids, maleic acid, azelaic acid, suberic acid, sebacic acid, fumaric acid, adipic acid, linoleic acid dimer, malonic acid, alkyl malonic acids, alkenyl malonic acids, and the like) with various alcohols (e.g., butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, ethylene glycol, diethylene glycol monoether, propylene glycol, and the like). Specific 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, dieicosyl sebacate, 2-ethylhexyl diester of linoleic acid dimer, complex ester (formed by reacting one mole of sebacic acid with two moles of tetraethylene glycol and two moles of 2-ethylhexanoic acid), and the like.

[0039] Esters useful as synthetic oils include, but are not limited to, esters made from alcohols (e.g., methanol, ethanol, etc.), polyols and polyol ethers (e.g., neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol, tripentaerythritol), and the like, and carboxylic acids having from about 5 to about 12 carbon atoms.

[0040] Silicon-based oils (such as polyalkylsiloxane oils, polyarylsiloxane oils, polyalkoxysiloxane oils, or polyaryloxysiloxane oils, and silicic acid oils) constitute another useful class of synthetic lubricating oils. Specific examples of these include, but are not limited to, tetraethyl silicate, tetra-isopropyl silicate, tetra-(2-ethylhexyl) silicate, tetra-(4-methyl-hexyl) silicate, tetra-(p-tert-butylphenyl) silicate, hexyl-(4-methyl-2-pentoxy)disiloxane, poly(methyl)siloxane, poly(methylphenyl)siloxane, and the like. Still other useful synthetic lubricating oils include, but are not limited to, liquid esters of phosphorus-containing acids (such as tricresyl phosphate, trioctyl phosphate, diethyl ester of decane phosphonic acid, and the like), tetrahydrofuran polymers, and the like.

[0041] Lubricating oils can be derived from unrefined, refined, and rerefined oils, either natural, synthetic, or mixtures of any two or more of these types disclosed above. Unrefined oils are those obtained directly from natural or synthetic sources (e.g., coal, shale, or tar sands bitumen) without further purification or treatment. Examples of unrefined oils include, but are not limited to, shale oils obtained directly from a retort operation, petroleum oils obtained directly from distillation, or ester oils obtained directly from an esterification process, each of which is then used without further treatment. Refined oils are similar to unrefined oils, except that they have been further treated in one or more purification steps to improve one or more properties. These purification techniques are known to those skilled in the art and include, for example, solvent extraction, secondary distillation, acid or base extraction, filtration, percolation, hydrotreating, dewaxing, and the like. Rerefined oils are obtained by treating used oils in processes similar to those used to obtain refined oils. Such rerefined oils are also known as reclaimed or reprocessed oils and are often additionally processed by techniques aimed at removing spent additives and oil breakdown products.

[0042] Lubricating oil basestocks derived from the hydroisomerization of wax may also be used, either alone or in combination with the aforementioned natural and / or synthetic basestocks. Such wax isomerate oils are produced by hydroisomerizing natural or synthetic waxes or mixtures thereof over a hydroisomerization catalyst.

[0043] Natural waxes are typically slack waxes recovered by the solvent dewaxing of mineral oils. Synthetic waxes are typically waxes produced by the Fischer-Tropsch process.

[0044] Other useful fluids of lubricating viscosity include non-conventional or unconventional base stocks, preferably catalytically or synthetically engineered to provide high performance lubricating properties.

[0045] Metal or metalloid hydrogen atom donor compounds The lubricating oil compositions herein may contain one or more metal or metalloid hydrogen atom donor compounds selected from the group consisting of silicon hydrides, germanium hydrides, and tin hydrides.

[0046] In one embodiment, the one or more metal or metalloid hydrogen atom donor compounds have the formula: [ka] In the formula, R1, R2, and R3 are each independently selected from a hydrogen atom, a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, a C3-C10 cycloalkyl group, -(OR4), -NR5R6, -O(=O)R7, or a chlorine atom, provided that two or more of R1, R2, and R3 are not hydrogen atoms, and R4 is a C6-C 14R5 is H, a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group; R6 is H, a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group; R7 is a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group; and M is a silicon atom, a germanium atom, or a tin atom.

[0047] In one embodiment, the one or more metal or metalloid hydrogen atom donor compounds have the formula: [ka] In the formula, R2 and R3 are each independently selected from a C6-C14 aryl group, an alkyl group, or a C3-C10 cycloalkyl group, -(OR4), -NR5R6, -O(=O)R7, or a chlorine atom; R4 is a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group; R5 is H, a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group; R6 is H, a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group; R7 is a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group; and M is a silicon atom, a germanium atom, or a tin atom.

[0048] In one embodiment, the one or more metal or metalloid hydrogen atom donor compounds have the formula: [ka] In the formula, R1, R2, and R3 are each independently selected from a hydrogen atom, a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, a C3-C10 cycloalkyl group, -(OR4), -NR5R6, -O(=O)R7, or a chlorine atom, provided that two or more of R1, R2, and R3 are not hydrogen atoms, R4 is a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group, R5 is H, a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group, R6 is H, a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group, and R7 is a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group.

[0049] In one embodiment, the one or more metal or metalloid hydrogen atom donor compounds have the formula: [ka] In the formula, R2 and R3 are each independently selected from a hydrogen atom, a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, a C3-C10 cycloalkyl group, -(OR4), -NR5R6, -O(=O)R7, or a chlorine atom; R4 is a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group; R5 is H, a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group; R6 is H, a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group; and R7 is a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group.

[0050] In one embodiment, the one or more metal or metalloid hydrogen atom donor compounds have the formula: [ka] In the formula, R1, R2, and R3 are each independently selected from a hydrogen atom, a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, a C3-C10 cycloalkyl group, -(OR4), -NR5R6, -O(=O)R7, or a chlorine atom, provided that two or more of R1, R2, and R3 are not hydrogen atoms, R4 is a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group, R5 is H, a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group, R6 is H, a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group, and R7 is a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group.

[0051] In one embodiment, the one or more metal or metalloid hydrogen atom donor compounds have the formula: [ka] In the formula, R1, R2, and R3 are each independently selected from a hydrogen atom, a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, a C3-C10 cycloalkyl group, -(OR4), -NR5R6, -O(=O)R7, or a chlorine atom, provided that two or more of R1, R2, and R3 are not hydrogen atoms, R4 is a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group, R5 is H, a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group, R6 is H, a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group, and R7 is a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group.

[0052] In one embodiment, the one or more metal or metalloid hydrogen atom donor compounds have the formula: [ka] In the formula, R8 is a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group, and n is 0 or an integer of 1-400.

[0053] In one embodiment, the one or more metal or metalloid hydrogen atom donor compounds have the formula: [ka] In the formula, n is 0 or an integer of 1 to 400.

[0054] In one embodiment, the one or more metal or metalloid hydrogen atom donor compounds have the formula: [ka] In the formula, R9 is a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, and m is an integer of 1 to 20.

[0055] In one embodiment, the metal or metalloid hydrogen atom donor compound is a compound in which a hydride is directly bonded to a metal atom, hi one embodiment, the metal hydride is not a silazane.

[0056] Generally, the amount of the metal or metalloid hydrogen atom donor compound can be from about 0.001% to about 25% by weight, from about 0.05% to about 20% by weight, or from about 0.1% to about 15% by weight, or from about 0.1% to about 5% by weight, or from about 0.1% to about 4.0% by weight, based on the total weight of the lubricating oil composition.

[0057] In one aspect, the present disclosure provides a lubricating engine oil composition for a direct injection boost spark ignition internal combustion engine comprising at least one metal hydride compound. In one embodiment, the amount of metal from the at least one metal or metalloid hydrogen atom donor compound is about 25 to about 3000 ppm, about 100 to about 3000 ppm, about 200 to about 3000 ppm, or about 250 to about 2500 ppm, about 300 to about 2500 ppm, about 350 to about 2500 ppm, about 400 ppm to about 2500 ppm, about 500 to about 2500 ppm, about 600 to about 2500 ppm, about 700 to about 2500 ppm, about 700 to about 2000 ppm, or about 700 to about 1500 ppm. In one embodiment, the amount of metal from the metal or metalloid hydrogen atom donor compound is about 2000 ppm or less, or about 1500 ppm or less. The metal in each of these embodiments is selected from silicon, germanium, tin, or combinations thereof.

[0058] In one embodiment, the metal or metalloid hydrogen atom donor compound may be combined with conventional lubricant detergent additives containing magnesium and / or calcium. In one embodiment, the calcium detergent(s) may be added to the lubricant composition in an amount sufficient to provide from 0 to about 2400 ppm calcium metal, from 0 to about 2200 ppm calcium metal, from 100 to about 2000 ppm calcium metal, from 200 to about 1800 ppm calcium metal, or from about 100 to about 1800 ppm calcium metal, or from about 200 to about 1500 ppm, or from about 300 to about 1400 ppm, or from about 400 to about 1400 ppm calcium metal in the lubricant composition. In one embodiment, the magnesium detergent(s) may be added to the lubricating oil composition in an amount sufficient to provide from about 100 to about 1000 ppm of magnesium metal, or from about 100 to about 600 ppm, or from about 100 to about 500 ppm, or from about 200 to about 500 ppm of magnesium metal in the lubricating oil composition.

[0059] In one embodiment, the metal or metalloid hydrogen atom donor compound may be combined with a conventional lubricant detergent additive containing lithium. In one embodiment, the lithium detergent(s) may be added to the lubricant composition in an amount sufficient to provide from 0 to about 2400 ppm lithium metal, from 0 to about 2200 ppm lithium metal, from 100 to about 2000 ppm lithium metal, from 200 to about 1800 ppm lithium metal, or from about 100 to about 1800 ppm, or from about 200 to about 1500 ppm, or from about 300 to about 1400 ppm, or from about 400 to about 1400 ppm lithium metal in the lubricant composition.

[0060] In one embodiment, the metal or metalloid hydrogen atom donor compound may be combined with a conventional lubricant detergent additive containing sodium. In one embodiment, the sodium detergent(s) may be added to the lubricant composition in an amount sufficient to provide from 0 to about 2400 ppm sodium metal, from 0 to about 2200 ppm sodium metal, from 100 to about 2000 ppm sodium metal, from 200 to about 1800 ppm sodium metal, or from about 100 to about 1800 ppm, or from about 200 to about 1500 ppm, or from about 300 to about 1400 ppm, or from about 400 to about 1400 ppm sodium metal in the lubricant composition.

[0061] In one embodiment, the metal or metalloid hydrogen atom donor compound may be combined with a conventional lubricating oil detergent additive containing potassium. In one embodiment, the potassium detergent(s) may be added to the lubricating oil composition in an amount sufficient to provide from 0 to about 2400 ppm potassium metal, from 0 to about 2200 ppm potassium metal, from 100 to about 2000 ppm potassium metal, from 200 to about 1800 ppm potassium metal, or from about 100 to about 1800 ppm, or from about 200 to about 1500 ppm, or from about 300 to about 1400 ppm, or from about 400 to about 1400 ppm potassium metal in the lubricating oil composition.

[0062] In one embodiment, the disclosure provides a lubricating engine oil composition comprising a lubricating oil basestock as a major component and at least one metal hydride compound as a minor component, wherein an engine exhibits greater than 50% reduced low speed pre-ignition compared to the low speed pre-ignition performance achieved in an engine using a lubricating oil without the at least one metal hydride compound, based on normalized low speed pre-ignition (LSPI) counts per 100,000 engine cycles, engine operation at 500-3,000 revolutions per minute, and a brake mean effective pressure (BMEP) of 10-30 bar.

[0063] In one aspect, the present disclosure provides a lubricating oil composition for use in a downsized boosted engine comprising a lubricating oil basestock as a major component and at least one metal hydride compound as a minor component, the downsized engine ranging in volume from about 0.5 to about 3.6 liters, from about 0.5 to about 3.0 liters, from about 0.8 to about 3.0 liters, from about 0.5 to about 2.0 liters, or from about 1.0 to about 2.0 liters. The engine may have 2, 3, 4, 5, or 6 cylinders.

[0064] In one aspect, the present disclosure provides the use of at least one metal or metalloid hydrogen atom donor compound to prevent or reduce low speed pre-ignition in a direct injection boosted spark ignition internal combustion engine.

[0065] Lubricant Additives In addition to the metal or metalloid hydrogen atom donor compounds described herein, the lubricating oil composition may contain additional lubricating oil additives.

[0066] The lubricating oil compositions of the present disclosure may also contain other conventional additives that can impart or improve any desired properties of the lubricating oil composition in which these additives are dispersed or dissolved. Any additive known to those skilled 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," 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. For example, the lubricating oil compositions can be blended with antioxidants, antiwear agents, metal detergents, rust inhibitors, haze removers, demulsifiers, metal deactivators, friction modifiers, pour point depressants, antifoam agents, co-solvents, corrosion inhibitors, ashless dispersants, multifunctional agents, dyes, extreme pressure agents, and the like, and mixtures thereof. A variety of additives are known and commercially available. These additives, or similar compounds thereof, may be used to prepare the lubricating oil compositions of this disclosure by conventional blending procedures.

[0067] The lubricating oil composition of the present invention may contain one or more detergents. Metal-containing or ash-forming detergents function both as detergents to reduce or remove deposits, and as acid neutralizers or rust inhibitors, thereby reducing wear and corrosion and extending engine life. Detergents generally contain a polar head with a long hydrophobic tail. The polar head comprises a metal salt of an acidic organic compound. The salts may contain substantially stoichiometric amounts of the metal, in which case they are usually described as normal or neutral salts. Large amounts of metal bases can be incorporated by reacting an excess of a metal compound (e.g., oxide or hydroxide) with an acid gas (e.g., carbon dioxide).

[0068] Detergents that may be used include oil-soluble neutral and overbased sulfonates, phenates, sulfurized phenates, thiophosphonates, salicylates, and naphthenates, as well as other oil-soluble carboxylates of metals, particularly alkali or alkaline earth metals such as barium, sodium, potassium, lithium, calcium, and magnesium. The most commonly used metals are calcium and magnesium, both of which may be present in detergents used in lubricants, as well as mixtures of calcium and / or magnesium with sodium.

[0069] The lubricating oil composition of the present invention may contain one or more antiwear agents capable of reducing friction and excessive wear. Any antiwear agent known to those skilled in the art may be used in the lubricating oil composition. Non-limiting examples of suitable antiwear agents include zinc dithiophosphates, metal salts of dithiophosphoric acids (e.g., Pb, Sb, Mo, etc.), metal salts of dithiocarbamic acids (e.g., Zn, Pb, Sb, Mo, etc.), metal salts of fatty acids (e.g., Zn, Pb, Sb, etc.), boron compounds, phosphate esters, phosphites, amine salts of phosphate esters or thiophosphate esters, reaction products of dicyclopentadiene and thiophosphoric acid, and combinations thereof. The amount of antiwear agent may vary from about 0.01 wt.% to about 5 wt.%, from about 0.05 wt.% to about 3 wt.%, or from about 0.1 wt.% to about 1 wt.%, based on the total weight of the lubricating oil composition.

[0070] In certain embodiments, the antiwear agent is or includes a dihydrocarbyl dithiophosphate metal salt, such as a zinc dialkyldithiophosphate compound. The metal of the dihydrocarbyl dithiophosphate metal salt may be an alkali metal or alkaline earth metal, or aluminum, lead, tin, molybdenum, manganese, nickel, or copper. In some embodiments, the metal is zinc. In other embodiments, the alkyl group of the dihydrocarbyl dithiophosphate metal salt has from about 3 to about 22 carbon atoms, from about 3 to about 18 carbon atoms, from about 3 to about 12 carbon atoms, or from about 3 to about 8 carbon atoms. In further embodiments, the alkyl group is linear or branched.

[0071] The amount of dihydrocarbyl dithiophosphate metal salt (including zinc dialkyl dithiophosphate salt) in the lubricating oil compositions disclosed herein is measured by its phosphorus content. In some embodiments, the phosphorus content of the lubricating oil compositions disclosed herein is from about 0.01 wt % to about 0.14 wt %, based on the total weight of the lubricating oil composition.

[0072] The lubricating oil composition of the present invention may contain one or more friction modifiers that can reduce friction between moving parts. Any friction modifier known to those skilled in the art may be used in the lubricating oil composition. Non-limiting examples of suitable friction modifiers include aliphatic carboxylic acids, derivatives of aliphatic carboxylic acids (e.g., alcohols, esters, borate esters, amides, metal salts, etc.), mono-, di-, or tri-alkyl substituted phosphoric or phosphonic acids, derivatives of mono-, di-, or tri-alkyl substituted phosphoric or phosphonic acids (e.g., esters, amides, metal salts, etc.), mono-, di-, or tri-alkyl substituted amines, mono-, di-, or tri-alkyl substituted amides, and combinations thereof. In some embodiments, examples of friction modifiers include alkoxylated fatty amines, boronated fatty epoxides, fatty phosphites, fatty epoxides, fatty amines, boronated alkoxylated fatty amines, metal salts of fatty acids, fatty acid amides, glycerol esters, boronated glycerol esters, and fatty imidazolines, C4-C6 fatty acid esters, as disclosed in U.S. Pat. No. 6,372,696, the contents of which are incorporated herein by reference. 75 Or C6~C 24 Or C6~C 20 and mixtures thereof. The amount of friction modifier may vary from about 0.01% to about 10% by weight, from about 0.05% to about 5% by weight, or from about 0.1% to about 3% by weight, based on the total weight of the lubricating oil composition.

[0073] The lubricating oil compositions of the present disclosure may include a molybdenum-containing friction modifier. The molybdenum-containing friction modifier may be any one of the known molybdenum-containing friction modifiers or known molybdenum-containing friction modifier compositions.

[0074] Preferred molybdenum-containing friction modifiers are, for example, sulfurized oxymolybdenum dithiocarbamate, sulfurized oxymolybdenum dithiophosphate, amine-molybdenum complex compounds, oxymolybdenum diethylate amide, and oxymolybdenum monoglyceride. Most preferred are molybdenum dithiocarbamate friction modifiers.

[0075] The lubricating oil composition of the present invention will generally contain a molybdenum-containing friction modifier in an amount of from 0.01 to 0.15% by weight, based on the molybdenum content.

[0076] The lubricating oil composition of the present invention preferably contains an organic antioxidant in an amount of 0.01-5 wt%, preferably 0.1-3 wt%. The antioxidant may be a hindered phenol antioxidant or a diarylamine antioxidant. Diarylamine antioxidants are advantageous in providing a base number derived from the nitrogen atom. Hindered phenol antioxidants are advantageous in that they do not produce NOx gases.

[0077] Examples of the hindered phenol antioxidant include 2,6-di-t-butyl-p-cresol, 4,4'-methylenebis(2,6-di-t-butylphenol), 4,4'-methylenebis(6-t-butyl-o-cresol), 4,4'-isopropylidenebis(2,6-di-t-butylphenol), 4,4'-bis(2,6-di-t-butylphenol), 2,2'-methylenebis(4-methyl-6-t-butylphenol), 4,4'-thiobis(2-methyl- 6-t-butylphenol), 2,2-thio-diethylenebis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, octyl 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, octadecyl 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, and octyl 3-(3,54-butyl-4-hydroxy-3-methylphenyl)propionate, as well as commercially available products such as, but not limited to, Irganox L135® (BASF), Naugalube 531® (Chemtura), and Ethanox 376® (SI Group).

[0078] Examples of diarylamine antioxidants include alkyldiphenylamines having alkyl groups of 3 to 9 carbon atoms, p,p-dioctyldiphenylamine, phenyl-naphthylamine, alkylated-naphthylamine, and mixtures of alkylated phenyl-naphthylamines. The diarylamine antioxidants may have 1 to 3 alkyl groups.

[0079] Each of the hindered phenol antioxidants and diarylamine antioxidants can be used alone or in combination. If desired, other oil-soluble antioxidants can be used in combination with the antioxidant(s) described above.

[0080] The lubricating oil compositions of the present invention may further contain oxymolybdenum complexes of succinimides, particularly sulfur-containing oxymolybdenum complexes of succinimides, which may provide increased oxidation protection when used in combination with the phenolic or aminic antioxidants described above.

[0081] In preparing lubricating oil formulations, the additives are typically introduced in the form of a 10 to 80% by weight concentrate of the active ingredient in a hydrocarbon oil (e.g., a mineral lubricating oil or other suitable solvent).

[0082] Typically, these concentrates may be diluted with 3 to 100 parts by weight (e.g., 5 to 40 parts by weight) of lubricating oil per part by weight of the additive package in forming the finished lubricant (e.g., crankcase motor oil). The purpose of the concentrate, of course, is to facilitate and simplify the handling of the various materials, as well as to facilitate dissolution or dispersion in the final blend.

[0083] Process for preparing lubricating oil composition The lubricating oil compositions disclosed herein can be prepared by any method known to those skilled in the art for making lubricating oils. In some embodiments, the base oil can be blended or mixed with the metal or metalloid hydrogen atom donor compound described herein. Optionally, in addition to the metal or metalloid hydrogen atom donor compound, one or more other additives can be added. The metal or metalloid hydrogen atom donor compound and the optional additives can be added to the base oil individually or simultaneously. In some embodiments, the metal or metalloid hydrogen atom donor compound and the optional additives are added to the base oil individually, in one or more additions, and the additions can be in any order. In other embodiments, the metal or metalloid hydrogen atom donor compound and the additives are added to the base oil simultaneously, optionally in the form of an additive concentrate. In some embodiments, solubilization of the metal or metalloid hydrogen atom donor compound or any solid additives in the base oil can be aided by heating the mixture to a temperature of about 25°C to about 200°C, about 50°C to about 150°C, or about 75°C to about 125°C.

[0084] Any mixing or dispersing device known to those skilled in the art can be used to blend, mix, or solubilize the ingredients. Blending, mixing, or solubilization can be performed in a blender, agitator, disperser, mixer (e.g., planetary mixer and double planetary mixer), homogenizer (e.g., Gaulin homogenizer and Ranney homogenizer), grinder (e.g., colloid mill, ball mill, and sand mill), or any other mixing or dispersing device known in the art.

[0085] Application of the lubricating oil composition The lubricating oil compositions disclosed herein may be suitable for use as motor oils (i.e., engine oils or crankcase oils) in spark-ignition internal combustion engines, particularly direct injection boosted engines (i.e., susceptible to low speed pre-ignition).

[0086] The following examples are presented to illustrate the embodiments of the present invention, but are not intended to limit the present invention to the specific embodiments described. Unless otherwise indicated, all parts and percentages are by weight. All numerical values ​​are approximate. When numerical ranges are given, it should be understood that embodiments outside the ranges described may still fall within the scope of the present invention. The specific details described in each example should not be interpreted as necessary features of the present invention. EXAMPLES

[0087] The following examples are intended for illustrative purposes only and do not limit the scope of the invention in any way.

[0088] Test compounds were blended into lubricating oils and their ability to reduce LSPI events was determined using the test method described below.

[0089] Low speed pre-ignition events were measured on a Ford 2.0L Ecoboost engine. The engine is a turbocharged gasoline direct injection (GDI) engine. The Ford Ecoboost engine is run in four replicates of approximately four hours. The engine is run at 1750 rpm, with an oil sump temperature of 95° C., and a brake mean effective pressure (BMEP) of 1.7 MPa. The engine is run for 175,000 combustion cycles at each stage and the LSPI events are counted.

[0090] LSPI events are determined by monitoring the peak cylinder pressure (PP) of the fuel charge in the cylinder and the crank angle at 2% mass fraction burned (MFB02). When both criteria are met, an LSPI event is said to have occurred. The peak cylinder pressure threshold varies by test, but is typically 4-5 standard deviations above the mean cylinder pressure. Similarly, the MFB02 threshold is typically 4-5 standard deviations earlier than the mean MFB02 (expressed in crank angles). LSPI events may be reported as average events per test, events per 100,000 combustion cycles, events per cycle, and / or combustion cycles per event. The results of this test are presented below.

[0091] Additives associated with the test lubricants that reduce the frequency of LSPI are considered additives that reduce the frequency of LSPI compared to the corresponding baseline lubricant. The test results are shown in Table 1.

[0092] Baseline formulation The baseline formulation contained Group 2 base oil, a mixture of primary and secondary zinc dialkyldithiophosphates in amounts to provide the lubricating oil composition with 737-814 ppm phosphorus, a polyisobutenyl succinimide dispersant (borated and ethylene carbonate post-treated), a molybdenum succinimide complex, an alkylated diphenylamine antioxidant, a borated friction modifier, a foam inhibitor, a pour point depressant, and an olefin copolymer viscosity index improver.

[0093] The lubricating oil composition was blended into a 5W-30 viscosity grade oil.

[0094] Metal or metalloid hydrogen atom donor compound A (Triphenylsilane) Triphenylsilane was commercially available from Millipore Sigma® or Gelest®.

[0095] Metal or metalloid hydrogen atom donor compound B (Tributylgermane) Tributylgermane was commercially available from Millipore Sigma®.

[0096] Example 1 A lubricating oil composition was prepared by adding 458 ppm of silicon from triphenylsilane and 2164 ppm of calcium from a combination of overbased Ca sulfonate and phenate detergents to the baseline formulation.

[0097] Comparative Example 1 A lubricating oil composition was prepared by adding 2255 ppm of calcium from a combination of overbased Ca sulfonate and phenate detergents to the baseline formulation.

[0098] Example 2 A lubricating oil composition was prepared by adding 1483 ppm of germanium from tributylgermane and 2204 ppm of calcium from a combination of overbased Ca sulfonate and phenate detergents to the baseline formulation. [Table 1]

[0099] These data show that examples of Applicant's invention including the disclosed metal or metalloid hydrogen atom donor compounds provided significantly superior LSPI performance in a Ford engine, both in terms of number of events and number of severe LSPI events, as compared to comparative examples not including a metal or metalloid hydrogen atom donor. The severity is reduced by reducing the number of high pressure events (i.e., 120 bar or higher) that could potentially damage the engine.

Claims

1. A lubricating oil composition comprising a metal or metalloid hydrogen atom donor compound selected from the group consisting of silicon hydrides, germanium hydrides, and tin hydrides.

2. The metal or metalloid hydrogen atom donor compound has the formula: 【Chemistry 1】 In the formula, R １ , R ２ , and R ３ are each independently a hydrogen atom, a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, a C3-C10 cycloalkyl group, -(OR ４ ), -NR ５ R ６ , -O(=O)R ７ or a chlorine atom, R １ , R ２ , and R ３ Two or more of R are not hydrogen atoms. ４ is C ６ -C １４ an aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group; R ５ is H, a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group; R ６ is H, a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group; R ７ 2. The lubricating oil of claim 1, wherein R is a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group, and M is a silicon atom, a germanium atom, or a tin atom.

3. The metal or metalloid hydrogen atom donor compound has the formula: 【Chemistry 2】 In the formula, R ２ and R ３ are each independently a C6-C14 aryl group, an alkyl group, or a C3-C10 cycloalkyl group, -(OR ４ ), -NR ５ R ６ , -O(=O)R ７ or a chlorine atom; R ４ is a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group; R ５ is H, a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group; R ６ is H, a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group; R ７ 3. The lubricating oil of claim 2, wherein R is a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group, and M is a silicon atom, a germanium atom, or a tin atom.

4. The metal or metalloid hydrogen atom donor compound has the formula: 【Chemistry 3】 In the formula, R １ , R ２ , and R ３ are each independently a hydrogen atom, a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, a C3-C10 cycloalkyl group, -(OR ４ ), -NR ５ R ６ , -O(=O)R ７ or a chlorine atom, R １ , R ２ , and R ３ Two or more of R are not hydrogen atoms. ４ is a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group; R ５ is H, a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group; R ６ is H, a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group; R ７ is a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group.

5. The metal or metalloid hydrogen atom donor compound has the formula: 【Chemistry 4】 In the formula, R ２ and R ３ are each independently a hydrogen atom, a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, a C3-C10 cycloalkyl group, -(OR ４ ), -NR ５ R ６ , -O(=O)R ７ or a chlorine atom; R ４ is a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group; R ５ is H, a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group; R ６ is H, a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group; R ７ is a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group.

6. The metal or metalloid hydrogen atom donor compound has the formula: 【Chemistry 5】 In the formula, R １ , R ２ , and R ３ are each independently a hydrogen atom, a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, a C3-C10 cycloalkyl group, -(OR ４ ), -NR ５ R ６ , -O(=O)R ７ or a chlorine atom, R １ , R ２ , and R ３ Two or more of R are not hydrogen atoms. ４ is a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group; R ５ is H, a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group; R ６ is H, a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group; R ７ is a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group.

7. The metal or metalloid hydrogen atom donor compound has the formula: 【Chemistry 6】 In the formula, R １ , R ２ , and R ３ are each independently a hydrogen atom, a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, a C3-C10 cycloalkyl group, -(OR ４ ), -NR ５ R ６ , -O(=O)R ７ or a chlorine atom, R １ , R ２ , and R ３ Two or more of R are not hydrogen atoms. ４ is a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group; R ５ is H, a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group; R ６ is H, a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group; R ７ is a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group.

8. The metal or metalloid hydrogen atom donor compound has the formula: 【Chemistry 7】 In the formula, R ８ is a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, or a C3-C10 cycloalkyl group; and n is 0 or an integer from 1 to 400.

9. The metal or metalloid hydrogen atom donor compound has the formula: 【Chemistry 8】 2. The lubricating oil composition of claim 1, wherein n is 0 or an integer from 1 to 400.

10. The metal or metalloid hydrogen atom donor compound has the formula: 【Chemistry 9】 In the formula, R ９ is a C6-C14 aryl group, a saturated or unsaturated C1-C30 alkyl group, and m is an integer from 1 to 20.

11. 10. The lubricating oil composition of claim 1, wherein the composition further comprises a detergent selected from calcium detergents, magnesium detergents, sodium detergents, lithium detergents, and potassium detergents.

12. 12. The lubricating oil composition of claim 11, wherein the detergent is a carboxylate, salicylate, phenate, or sulfonate detergent.

13. The lubricating oil composition of claim 1 , wherein the composition further comprises a molybdenum-containing compound.

14. 10. The lubricating oil composition of claim 1, wherein the composition further comprises at least one other additive selected from ashless dispersants, ashless antioxidants, phosphorus-containing anti-wear additives, friction modifiers, and polymeric viscosity modifiers.

15. 1. A method for preventing or reducing low speed pre-ignition in a direct injection boosted spark ignition internal combustion engine, the method comprising the step of lubricating a crankcase of the engine with a lubricating oil composition comprising from about 25 to about 3000 ppm metal from at least one metal or metalloid hydrogen atom donor compound selected from the group consisting of silicon hydrides, germanium hydrides, and tin hydrides, based on a total weight of the lubricating oil composition.

16. 1. Use of at least one metal or metalloid hydrogen atom donor compound selected from the group consisting of silicon hydrides, germanium hydrides, and tin hydrides in a lubricating engine oil composition to prevent or reduce low speed pre-ignition in a direct injection boosted spark ignition internal combustion engine.

17. 17. The use of claim 16, wherein the at least one metal or metalloid hydrogen atom donor compound is present at about 25 to about 3000 ppm metal from the metal hydride, based on the total weight of the lubricating oil composition.

18. 17. The use according to claim 16, wherein the engine is a miniature boosted engine in the range of 0.5 litres to 3.6 litres.

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