A method for preventing or reducing low-speed premature ignition in a direct-injection spark-ignition engine using silane-containing lubricating oil.

Abstract

This paper proposes a method to prevent or reduce low-speed premature ignition in engines lubricated with compound oil. [Solution] The method includes the step of lubricating the crankcase of an engine with a lubricating oil composition containing about 100 to about 3000 ppm of silicon derived from at least one silane-containing compound, based on the total weight of the lubricating oil composition.

Description

Technical Field

[0001] The present disclosure relates to a lubricant composition for a boosted direct injection spark ignition internal combustion engine containing at least one silane compound. The present disclosure also relates to a method for preventing or reducing low speed pre-ignition in an engine lubricated with a formulated oil. The formulated oil has a composition containing at least one oil-soluble or oil-dispersible silane compound.

Background Art

[0002] In recent years, engine manufacturers have developed smaller engines that achieve higher power density and excellent performance while reducing friction and pump losses. This is achieved by increasing the intake air pressure using a turbocharger or a mechanical supercharger and reducing the engine speed using a higher gear ratio enabled by the generation of higher torque at lower engine speeds. However, higher torque at lower engine speeds has been found to cause accidental pre-ignition in the low-speed engine, and this phenomenon is known as low speed pre-ignition or LSPI, which results in extremely high cylinder peak pressures and can lead to catastrophic engine failure. The possibility of LSPI hinders the complete optimization of engine torque at lower engine speeds in such smaller, high-output engines by engine manufacturers.

[0003] One of the leading theories regarding the cause of low speed pre-ignition (LSPI) is at least partially due to the auto-ignition of engine oil droplets entering the engine combustion chamber from the piston crevice under high pressure during the period when the engine is operating at low speed and the compression process time is at its longest (Amann et al., SAE 2012-01-1140).

[0004] Some engine knocking and pre-ignition problems can be solved, and have been solved, by the use of new engine technologies such as electronic control and knock sensors, and the optimization of engine operating conditions. However, there is a need for a lubricating oil composition that can reduce or prevent the LSPI problem and improve or maintain other properties such as wear and oxidation protection.

Summary of the Invention

Problems to be Solved by the Invention

[0005] The inventors have discovered a solution to address the LSPI problem by using a silane-containing additive.

Means for Solving the Problems

[0006] An engine lubricating oil composition for use in a boosted small engine, comprising a lubricating oil base material as a main component and at least one silane-containing compound as a minor component, wherein the small engine is in the range of 0.5 liters to 3.6 liters, is disclosed.

[0007] Also disclosed is a method for preventing or reducing low-speed pre-ignition in a boosted direct injection spark ignition internal combustion engine, the method comprising lubricating the crankcase of the engine with a lubricating oil composition comprising from about 100 to about 3000 ppm of silicon derived from at least one silane-containing compound, based on the total weight of the lubricating oil composition.

[0008] Further disclosed is the use of at least one silane-containing compound in an engine lubricating oil composition for preventing or reducing low-speed pre-ignition in a boosted direct injection spark ignition internal combustion engine.

Modes for Carrying Out the Invention

[0009] The term "boosted" is used throughout this specification. Boosted refers to operating the engine at an intake pressure higher than that of a naturally aspirated engine. Boosted conditions can be achieved by using a turbocharger (exhaust gas driven) or a supercharger (engine driven). "Boosted" allows engine manufacturers to use smaller engines with higher power densities to achieve excellent performance while reducing friction and pump losses.

[0010] Throughout this specification and the claims, the terms oil-soluble or oil-dispersible are used. Oil-soluble or oil-dispersible means that by dissolving, dispersing, or suspending in an oil of lubricating viscosity, the material can be incorporated in the amount necessary to achieve a desired level of activity or performance. Typically, this means that at least about 0.001% by weight of the material can be incorporated into the lubricating oil composition. For further consideration of the terms oil-soluble and oil-dispersible, and in particular "stable dispersibility," see U.S. Patent No. 4,320,019, expressly incorporated herein by reference for relevant teachings relating thereto.

[0011] As used herein, the term "sulfate ash" refers to the non-flammable residue resulting from metal additives in detergents and lubricants. Sulfate ash can be determined using ASTM test D874.

[0012] As used herein, the term "Total Base Number" or "TBN" refers to the amount of base equivalent to the number of milligrams of KOH in one gram of sample. Therefore, a higher TBN number reflects more alkali products and, consequently, higher alkalinity. TBN was determined using the ASTM D2896 test. Unless otherwise specified, all percentages are expressed in weight percent.

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

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

[0015] In one embodiment, the level of sulfated ash produced by the lubricating oil composition of the present invention is about 1.60% by weight or less, as determined by ASTM D874, for example, a level of sulfated ash of about 0.10 to about 1.60% by weight, as determined by ASTM D874. In one embodiment, the level of sulfated ash produced by the lubricating oil composition of the present invention is about 1.00% by weight or less, as determined by ASTM D874, for example, a level of sulfated ash of about 0.10 to about 1.00% by weight, as determined by ASTM D874. In one embodiment, the level of sulfated ash produced by the lubricating oil composition of the present invention is about 0.80% by weight or less, as determined by ASTM D874, for example, a level of sulfated ash of about 0.10 to about 0.80% by weight, as determined by ASTM D874. In one embodiment, the level of sulfated ash produced by the lubricating oil composition of the present invention is about 0.60% by weight or less, as determined by ASTM D874, for example, a level of sulfated ash of about 0.10 to about 0.60% by weight, as determined by ASTM D874.

[0016] The lubricating oil composition of the present invention may optionally have a total base number (TBN) of 4 to 15 mg KOH / g (for example, 5 to 12 mg KOH / g, 6 to 12 mg KOH / g, or 8 to 12 mg KOH / g).

[0017] Low-speed pre-ignition is most likely to occur in a boosted (turbocharged or supercharged) direct-injection spark-ignition (gasoline) internal combustion engine that generates a net mean effective pressure level (peak torque) greater than approximately 15 bar (e.g., at least approximately 18 bar, in particular at least approximately 20 bar) at engine speeds of approximately 1500 to approximately 2500 revolutions per minute (rpm) during operation (e.g., engine speeds of approximately 1500 to approximately 2000 rpm). As used herein, net mean effective pressure (BMEP) is defined as the amount of work achieved in one engine cycle divided by the engine's stroke volume, and engine torque normalized by engine displacement. The term "brake" refers to the actual torque / horsepower obtained at the engine flywheel as measured by a dynamometer. Therefore, BMEP is a standard for measuring the useful output of an engine.

[0018] In one embodiment of the present invention, the engine operates at a speed of 500 rpm to 3000 rpm, or 800 rpm to 2800 rpm, or even 1000 rpm to 2600 rpm. Furthermore, the engine may operate at a net mean effective pressure of 10 bar to 30 bar, or 12 bar to 24 bar.

[0019] Although relatively rare, LSPI events can be inherently catastrophic. Therefore, a significant reduction or even elimination of LSPI events during normal or sustained operation of a direct fuel injection engine is desirable. In one embodiment, the method of the present invention may result in fewer than 150 LSPI events per million combustion cycles (which can also be expressed as 15 LSPI events / 100,000 combustion cycles), fewer than 100 LSPI events per million combustion cycles, fewer than 70 LSPI events per million combustion cycles, fewer than 60 LSPI events per million combustion cycles, fewer than 50 LSPI events per million combustion cycles, fewer than 40 LSPI events per million combustion cycles, fewer than 30 LSPI events per million combustion cycles, fewer than 20 LSPI events per million combustion cycles, or fewer than 10 LSPI events per million combustion cycles, or even zero LSPI events per million combustion cycles.

[0020] Accordingly, in one embodiment, the present disclosure provides a method for preventing or reducing low-speed premature ignition in a boost direct-injection spark-ignition internal combustion engine, comprising the step of lubricating the crankcase of the engine with a lubricating oil composition comprising at least one silane-containing compound. In one embodiment, the amount of silicon derived from at least one silane compound is about 100 to about 3000 ppm, about 200 to about 3000 ppm, 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, and about 700 to about 1500 ppm in the lubricating oil composition. In one embodiment, the amount of silicon derived from the silane-containing 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 reduces the number of LSPI events by at least 10%, at least 20%, at least 30%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 95% compared to an oil that does not contain at least one silane-containing compound.

[0022] In another embodiment, the disclosure provides a method for reducing the severity of low-speed premature ignition events in a boost direct-injection spark-ignition internal combustion engine, comprising the step of lubricating the crankcase of the engine with a lubricating oil composition comprising at least one silane-containing compound. LSPI events are determined by monitoring the peak in-cylinder pressure (PP) and the mass combustion ratio (MFB) of the fuel filled in the cylinder. An LSPI event can be considered to have occurred if either or both of the criteria are met. The peak in-cylinder pressure threshold varies from test to test but is typically 4–5 standard deviations greater than the average in-cylinder pressure. Similarly, the MFB threshold is typically 4–5 standard deviations earlier than the average MFB (expressed in crank angle). LSPI events may be reported in terms of the average number of events per test, the number of events per 100,000 combustion cycles, the number of events per cycle, and / or the number of combustion cycles per event. In one embodiment, when both the MFB02 and peak pressure (PP) requirements were greater than 90 bar, the number of LSPI events per 100,000 combustion cycles was less than 15, less than 14, less than 13, less than 12, less than 11, less than 10, less than 9, less than 8, less than 7, less than 6, less than 5, less than 4, less than 3, less than 2, or less than 1. In one embodiment, the number of LSPI events with pressures greater than 90 bar was zero, or in other words, LSPI events with pressures greater than 90 bar were completely suppressed. In one embodiment, when both the MFB02 and peak pressure (PP) requirements were at a pressure greater than 100 bar, the number of LSPI events per 100,000 combustion cycles was less than 15, less than 14, less than 13, less than 12, less than 11, less than 10, less than 9, less than 8, less than 7, less than 6, less than 5, less than 4, less than 3, less than 2, or less than 1. In one embodiment, the number of LSPI events at pressures greater than 100 bar was zero, or in other words, LSPI events at pressures greater than 100 bar were completely suppressed.In one embodiment, when both the MFB02 and peak pressure (PP) requirements were greater than 110 bar, the number of LSPI events per 100,000 combustion cycles was less than 15, less than 14, less than 13, less than 12, less than 11, less than 10, less than 9, less than 8, less than 7, less than 6, less than 5, less than 4, less than 3, less than 2, or less than 1. In one embodiment, the number of LSPI events with pressures greater than 110 bar was zero, or in other words, LSPI events with pressures greater than 110 bar were completely suppressed. For example, when both the MFB02 and peak pressure (PP) requirements were at pressures exceeding 120 bar, the number of LSPI events per 100,000 combustion cycles was less than 15, less than 14, less than 13, less than 12, less than 11, less than 10, less than 9, less than 8, less than 7, less than 6, less than 5, less than 4, less than 3, less than 2, or less than 1. In one embodiment, the number of LSPI events exceeding 120 bar was zero, or in other words, extremely severe LSPI events (i.e., events exceeding 120 bar) were completely suppressed.

[0023] It has now been discovered that the occurrence of LSPI in engines, which are prone to LSPI, can be reduced by lubricating the engine with a lubricating oil composition containing a silane-containing compound.

[0024] This disclosure further provides the method described herein for an engine being fueled with a liquid hydrocarbon fuel, a liquid non-hydrocarbon fuel, or a mixture thereof.

[0025] This disclosure further provides the method described herein for an engine being fueled with natural gas, liquefied petroleum gas (LPG), compressed natural gas (CNG), or a mixture thereof.

[0026] Lubricating oil compositions suitable for use as motor oil in passenger cars conventionally contain a large amount of lubricating viscous oil and a small amount of performance-enhancing additives (such as ash-containing compounds). Conveniently, silicon is introduced into the lubricating oil compositions used in the practice of this disclosure by one or more silane-containing compounds.

[0027] Lubricating viscous oil / base oil component The lubricating viscous oil used in the lubricating oil compositions of this disclosure, also called the base oil, is typically present in large quantities, for example, more than 50% by weight, preferably more than about 70% by weight, more preferably about 80 to about 99.5% by weight, and most preferably about 85 to about 98% by weight, based on the total weight of the composition. When used herein, the term “base oil” should be understood to mean a base material or blend of base materials that are lubricating components, manufactured by one manufacturer to the same specifications (regardless of the raw materials or the location of the manufacturer), meeting the specifications of the same manufacturer, and identified by a unique formulation, product identification number, or both. The base oils used herein may be any known or subsequently discovered lubricating viscous oil used in formulating lubricating oil compositions for any and all applications, e.g., engine oil, marine cylinder oil, functional fluids (hydraulic fluid, gear oil, transmission fluid, etc.). Furthermore, the base oil used herein may optionally contain viscosity index improvers, such as high molecular weight alkyl methacrylates, olefin copolymers, such as ethylene-propylene copolymers or styrene-diene copolymers, and mixtures thereof.

[0028] As those skilled in the art will readily understand, the viscosity of the base oil is determined by its application. Accordingly, the viscosity of the base oils used herein is typically in the range of about 2 to about 2000 centistokes (cSt) at 100 degrees Celsius. Generally, base oils used individually as engine oils have a kinematic viscosity in the range of about 2 to about 30 cSt, preferably about 3 to about 16 cSt, and most preferably about 4 to about 12 cSt at 100°C, and are selected or blended according to the desired end application. Additives in the finished oil to obtain engine oil of the desired quality, such as lubricating oil compositions, are 0W, 0W-4, 0 It has SAE viscosity grades such as W-8, 0W-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, and 40.

[0029] Group I base oils generally refer to lubricating base oils derived from crude oil with a saturation content of less than 90% by weight (as determined by ASTM D2007) and / or a total sulfur content of more than 300 ppm (as determined by ASTM D2622, ASTM D4294, ASTM D4297, or ASTM D3120) and a viscosity index (VI) of 80 or more and less than 120 (as determined by ASTM D2270).

[0030] Group II base oils generally refer to lubricating base oils derived from crude oil with a total sulfur content of 300 ppm (parts per million) or less (as determined by ASTM D2622, ASTM D4294, ASTM D4927, or ASTM D3120), a saturation content of 90% by weight or more (as determined by ASTM D2007), and a viscosity index (VI) between 80 and 120 (as determined by ASTM D2270).

[0031] Group III base oils generally refer to lubricating base oils derived from crude oil with a sulfur content of less than 300 ppm, a saturation content of more than 90% by weight, and a VI of 120 or higher.

[0032] The base oil for Group IV is polyalphaolefin (PAO).

[0033] Group V base oils include all other base oils not included in Groups I, II, III, or IV.

[0034] Lubricating oil compositions may contain small amounts of other base oil components. For example, lubricating oil compositions may contain small amounts of base oil derived from natural lubricants, synthetic lubricants, or mixtures thereof. Suitable base oils include substrates obtained by isomerization of synthetic waxes and slack waxes, and hydrocracking substrates produced by hydrocracking (not solvent extraction) of aromatic and polar components of crude oil.

[0035] Suitable natural oils include, for example, liquid petroleum, solvent-treated or acid-treated paraffins, naphthenes or mixed paraffin-naphthene type mineral oil lubricants, coal or shale-derived oils, animal oils, and vegetable oils (e.g., rapeseed oil, castor oil, and lard).

[0036] Suitable synthetic lubricants include, but are not limited to, polymerized and copolymerized olefins, such as polybutylene, polypropylene, propylene-isobutylene copolymers, chlorinated polybutylene, poly(1-hexene), poly(1-octene), poly(1-decene), etc., and mixtures thereof, as well as hydrocarbon oils and halo-substituted hydrocarbon oils; alkylbenzenes such as dodecylbenzene, tetradecylbenzene, dinonylbenzene, and di(2-ethylhexyl)benzene; polyphenyls such as biphenyl, terphenyl, and alkylated polyphenyl; alkylated diphenyl ethers and alkylated diphenyl sulfides, as well as derivatives, analogs, and homologs thereof.

[0037] Other synthetic lubricants include, but are not limited to, oils produced by polymerizing olefins with fewer than five carbon atoms, such as ethylene, propylene, butylene, isobutene, pentene, and mixtures thereof. Methods for preparing such polymer oils are well known to those skilled in the art.

[0038] Examples of additional synthetic hydrocarbon oils include liquid polymers of α-olefins with appropriate viscosity. Particularly useful synthetic hydrocarbon oils include, for example, C6-C6 olefins such as 1-decene trimers. 12 It is a hydrogenated liquid oligomer of α-olefin.

[0039] Other categories of synthetic lubricants include, but are not limited to, alkylene oxide polymers, i.e., homopolymers, copolymers, and derivatives thereof (in which terminal hydroxyl groups are modified, for example, by esterification or etherification). These oils include ethylene oxide or propylene oxide, alkyl and phenyl ethers of these polyoxyalkylene polymers (e.g., methyl polypropylene glycol ether with an average molecular weight of 1,000, diphenyl ether of polyethylene glycol with a molecular weight of 500-1,000, diethyl ether of polypropylene glycol with a molecular weight of 1,000-1,500, etc.), or mono and polycarboxylic acid esters thereof, for example, acetate esters, mixed C3-C8 fatty acid esters, or C3 of tetraethylene glycol. 13 This is exemplified by oils prepared by polymerization of oxoacid diesters.

[0040] Further classifications of synthetic lubricants include, but are not limited to, esters of dicarboxylic acids, such as phthalic acid, succinic acid, alkyl succinic acid, alkenyl succinic acid, maleic acid, azelaic acid, suberic acid, sebacic acid, fumaric acid, adipic acid, linoleic acid dimer, malonic acid, alkyl malonic acid, alkenyl malonic acid, etc., with various alcohols, such as butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, ethylene glycol, diethylene glycol monoether, propylene glycol, etc. Specific examples of these esters include dibutyl adipate, di(2-ethylhexyl)sebacate, di-n-hexyl fumarate, dioctylsebacate, diisooctylazelaic acid, diisodecylazelaic acid, dioctylphthalate, didecylphthalate, dieicosylsebacate, 2-ethylhexyl diester of linoleic acid dimer, and composite esters formed by reacting 1 mole of sebaciic acid with 2 moles of tetraethylene glycol and 2 moles of 2-ethylhexanoic acid.

[0041] Furthermore, useful esters as synthetic oils include, but are not limited to, those made from carboxylic acids having about 5 to about 12 carbon atoms and alcohols (e.g., methanol, ethanol, etc.), polyols and polyol ethers, such as neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol, tripentaerythritol, etc.

[0042] For example, silicon-based oils such as polyalkyl-, polyaryl-, polyalkoxy-, or polyaryloxy-siloxane oils and silicate oils constitute another useful category of synthetic lubricants. Specific examples, though not limited to these, include tetraethyl silicate, tetraisopropyl silicate, tetra(2-ethylhexyl) silicate, tetra(4-methylhexyl) silicate, tetra(p-tert-butylphenyl) silicate, hexyl-(4-methyl-2-pentaoxy)disiloxane, poly(methyl)siloxane, and poly(methylphenyl)siloxane. Further useful synthetic lubricants, though not limited to these, include liquid esters of phosphorus-containing acids, such as diethyl esters of tricresyl phosphate, trioctyl phosphate, and decanephosphonic acid, and high molecular weight tetrahydrofuran.

[0043] Lubricating oils may be derived from unrefined, refined, or re-refined oils, either natural or synthetic, or mixtures of two or more such oils of the types disclosed above. Unrefined oils are obtained directly from natural or synthetic sources (e.g., coal, shale, or tar sand bitumen) without further refinement or processing. Examples of unrefined oils, but not limited to, include shale oil obtained directly from retort extraction operations, petroleum obtained directly from distillation, or ester oil obtained directly from esterification processes, each of which is then used without further processing. Refined oils are similar to unrefined oils except that they have been further processed in one or more refining steps to improve one or more properties. These refining techniques are known to those skilled in the art and include, for example, solvent extraction, secondary distillation, acid or base extraction, filtration, percolation, hydrogenation, and dewaxing. Re-refined oils are obtained by processing spent oil in a process similar to that used to obtain refined oils. Such re-refined oils, also known as recovered or reprocessed oils, are often subjected to additional processing using techniques aimed at removing spent additives and oily decomposition products.

[0044] Lubricant bases derived from the hydroisomerization of waxes can also be used alone or in combination with said natural and / or synthetic bases. Such wax isomerization oils are produced by hydroisomerizing natural or synthetic waxes or mixtures thereof in the presence of a hydroisomerization catalyst.

[0045] Natural waxes are typically slack waxes recovered by solvent dewaxing of mineral oils, and synthetic waxes are typically waxes produced by the Fischer-Tropsch process.

[0046] Other useful lubricating viscous fluids include unconventional or anomalous bases that have preferably been treated or synthesized catalytically to achieve high-performance lubricating properties.

[0047] Silane compounds The lubricant compositions herein can contain one or more silane-containing compounds. <able>

[0048] In one embodiment, the silane can have the following general formula (I): [(R 1 ) 3-a (R 2 O) a Si] r A (I) Wherein, R 1 is selected from the group consisting of saturated and unsaturated hydrocarbyls and chain-substituted saturated and unsaturated hydrocarbyls, R 2 is selected from the group consisting of hydrogen, saturated and unsaturated hydrocarbyls and chain-substituted saturated and unsaturated hydrocarbyls, a is an integer from 1 to 3, and A is a group with a valence r (r is an integer greater than or equal to 1), and is selected from the group consisting of saturated and unsaturated linear, branched or cyclic hydrocarbyl groups, oxygen atoms, or linear, branched or cyclic siloxane or polysiloxane groups (excluding oxygen atoms, each of which optionally contains substituents having oxygen, nitrogen, sulfur, or halogen heteroatoms).

[0049] Preferred silanes are those corresponding to formula (I) (wherein r is 1), and their oligomers formed by hydrolysis, hydrosilylation, or polymerization. When r is 1, A is preferably a saturated or unsaturated linear, branched, or cyclic hydrocarbyl group containing, optionally, an N-bonding group (e.g., amine, imine, carbamate, thiocarbamate, isocyanate, isocyanurate, etc.), an O-bonding group (e.g., ester, ether, polyether group, etc.), an S-bonding group (e.g., mercaptan, blocked mercaptan, thioether, thioester, sulfide, polysulfide, etc.), or a C-bonding group (e.g., carbonyl or carbonyl derivatives such as acetal, ketal, thioketal, nitrile, cyanate, thiocyanate, etc.). Preferably, when r is 1, A is selected from the group of linear or branched hydrocarbyl groups containing 1 to 24 carbon atoms, such as methyl, ethyl, propyl, butyl, hexyl, octyl, nonyl, methyl ethyl, methyl propyl, methyl butyl, decyl, dodecyl, and diethyleneyl benzyl. More preferably, when r is 1, A is selected from linear or branched hydrocarbyl groups containing 2 to 18 carbon atoms, most preferably 4 to 12 carbon atoms.

[0050] In one embodiment, the silane corresponds to formula (I) (where r is 2). Such an additive corresponds to general formula (II): (R 1 3-a )(R 2 O) a -Si-B-Si-(OR 2 ) a (R 1 3-a ) (II) [In the formula, R 1 , R 2 , and a are as described above in formula (I), and B is a divalent group selected from the group consisting of saturated or unsaturated linear, branched or cyclic hydrocarbyl groups, oxygen atoms, linear, branched or cyclic siloxane or polysiloxane groups, which, except for the oxygen atom, are oxygen, nitrogen, sulfur, halogen heteroatoms, (CR 4 R5 ) b (CR 6 R 7 ) c , C b H 2b -X'-C c H 2c , (CR 4 R 5 ) p -X'-(CR 6 R 7 ) q and CycloC s H q (C b H 2b ) t The compound optionally includes substituents having R, where R 4 , R 5 , R 6 and R 7 x' is either the same or different, independently selected from the group consisting of hydrogen, saturated and unsaturated hydrocarbyls, and saturated and unsaturated chain-substituted hydrocarbyls, b, c, p and q are independently integers selected from 1 to 18, s is an integer greater than 2, t is an integer greater than 1, a is an integer from 1 to 3, and X' is [ka] A selection from the group consisting of and mixtures thereof, in the formula, R 4 , R 5 , R 6 and R 7 These are independently the same or different, as described above. Preferably, when r is 2, A is the dialkylene polysulfide unit CH2CH2CH2S u The formula is CH2CH2CH2, where u is an integer from 1 to 10, most preferably an average value of 2 or 4. In one embodiment, a is 3.

[0051] Preferably, X' contains a sulfur atom. In one embodiment, X' is [ka] Selected from.

[0052] In general formulas (I) and (II), R 1 and R 2 Preferably, independently, C1~C 18 Selected from the group consisting of alkyl, aryl, alkalil, alkoxyaryl, alkoxyalkyl, and alkylthioalkyl.

[0053] Comfortable, R 1 and R 2 The following are independently selected from the group consisting of C1-C8 linear, branched, or cyclic alkyl groups, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, isopropyl, isobutyl, isopentyl, isoheptyl, isooctyl, sec-butyl, 1-methylbutyl, 1-ethylpropyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclooctyl, etc., aryl, alkalil, alkoxyaryl, or alkoxyalkyl groups, such as phenyl, tolyl, xylyl, benzyl, methoxyphenyl, methoxymethyl, methoxyethyl, ethoxymethyl, ethoxyethyl, etc., and ethylthiomethyl, methylthioethyl, etc.

[0054] Even more comfortable, R 1 and R 2 The following are independently selected from the group consisting of methyl, ethyl, propyl, butyl, pentyl, isopropyl, isobutyl, isopentyl, sec-butyl, 1-methylbutyl, 1-ethylpropyl, cyclopentyl, cyclohexyl, phenyl, tolyl, benzyl, and methoxyethyl.

[0055] Most preferably, R 1 and R 2 These are independently selected from the group consisting of methyl and ethyl.

[0056] Preferably, R 4 , R 5 , R 6 and R 7 These are, independently, hydrogen, C1~C 18Selected from the group consisting of alkyl, aryl, alkalil, alkoxyaryl, alkoxyalkyl, and alkylthioalkyl.

[0057] Comfortable, R 4 , R 5 , R 6 and R 7 The following are independently selected from the group consisting of hydrogen, C1-C8 linear, branched, or cyclic alkyl groups, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, isopropyl, isobutyl, isopentyl, isoheptyl, isooctyl, sec-butyl, 1-methylbutyl, 1-ethylpropyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclooctyl, etc.; aryl, alkaryl, alkoxyaryl, or alkoxyalkyl groups, such as phenyl, tolyl, xylyl, benzyl, methoxyphenyl, methoxymethyl, methoxyethyl, ethoxymethyl, ethoxyethyl, etc.; and ethylthiomethyl, methylthioethyl, etc.

[0058] Even more comfortable, R 4 , R 5 , R 6 and R 7 The following are independently selected from the group consisting of hydrogen, methyl, ethyl, propyl, butyl, pentyl, isopropyl, isobutyl, isopentyl, sec-butyl, 1-methylbutyl, 1-ethylpropyl, cyclopentyl, cyclohexyl, phenyl, tolyl, benzyl, and methoxyethyl.

[0059] R 4 , R 5 , R 6 and R 7 Most preferably, it is all hydrogen.

[0060] Furthermore, polyvalent types of A, such as the isomer of triethyleneylcyclohexane (CH2CH2)3C6H9 (in this case, r is 3), are also preferred.

[0061] Examples of silanes of this disclosure, but not limited to these, include bis(3-triethoxysilyl-1-propyl)tetrasulfide, bis(3-triethoxysilyl-1-propyl)disulfide, 1,2-bis-(triethoxysilyl)ethane, 1,4-bis-(triethoxysilyl)butane, 1,6-bis-(triethoxysilyl)hexane, octyltriethoxysilane, and 1,2,4-tris-(2-trimethoxysilylethyl)cyclohexane.

[0062] In one embodiment, the silane of the Disclosure also contains at least one sulfur atom in the molecule.

[0063] Other silanes having two Si-containing moieties are described in U.S. Patents No. 6,127,468 and No. 6,359,046, which are incorporated herein by reference.

[0064] The oligomer silane structures and their preparations are described in U.S. Patents No. 4,950,779 and No. 6,140,445, which are incorporated herein by reference.

[0065] References for the preparation of monomeric silanes are found in "Chemistry and Technology of Silicones," W. Noll, 1968, Academic Press, New York, or "Silane Coupling Agents," 2nd edition, E. Pleuddemann, 1991, Plenum Publishing, New York, which are incorporated herein by reference.

[0066] Methods for producing sulfur silane can be found in U.S. Patents No. 5,596,116 and No. 5,489,701, along with the references contained herein, which are incorporated herein by reference.

[0067] Examples of suitable commercially available silane additives are shown below: [ka]

[0068] Generally, the amount of silane-containing compound may be about 0.001% to about 25% by weight, about 0.05% to about 20% by weight, or about 0.1% to about 15% by weight, or about 0.1% to about 5% by weight, or about 0.1% to about 4.0% by weight, based on the total weight of the lubricating oil composition.

[0069] In one embodiment, the present disclosure provides a lubricating engine oil composition for a boost direct-injection spark-ignition internal combustion engine comprising at least one silicon-containing compound. In one embodiment, the amount of silicon derived from at least one silane-containing compound is, based on the total weight of the lubricating oil composition, about 100 to about 3000 ppm, about 200 to about 3000 ppm, about 200 to about 2500 ppm, about 200 to about 2000 ppm, about 200 to about 1500 ppm, or about 250 to about 2500 ppm, or about 250 to about 2000 ppm. m, or approximately 250 to approximately 1500 ppm, or approximately 250 to approximately 1200 ppm, approximately 300 to approximately 2500 ppm, approximately 350 to approximately 2500 ppm, approximately 400 ppm to approximately 2500 ppm, approximately 500 to approximately 2500 ppm, approximately 600 to approximately 2500 ppm, approximately 700 to approximately 2500 ppm, approximately 700 to approximately 2000 ppm, or approximately 700 to approximately 1500 ppm. In one embodiment, the amount of silicon derived from the silane-containing compound is approximately 2000 ppm or less or approximately 1500 ppm or less, based on the total weight of the lubricating oil composition.

[0070] In one embodiment, a silane-containing compound can be combined with a conventional lubricating oil detergent additive containing magnesium and / or calcium. In one embodiment, one or more calcium detergents can be added to the lubricating oil composition in an amount sufficient to provide the composition with 0 to about 2400 ppm of calcium metal, 0 to about 2200 ppm of calcium metal, 100 to about 2000 ppm of calcium metal, 200 to about 1800 ppm of calcium metal, or about 100 to about 1800 ppm, or about 200 to about 1500 ppm, or about 300 to about 1400 ppm, or about 400 to about 1400 ppm of calcium metal. In one embodiment, magnesium detergent(s) can be added to the lubricating oil composition in an amount sufficient to provide the composition with approximately 100 to approximately 1000 ppm of magnesium metal, or approximately 100 to approximately 600 ppm, or approximately 100 to approximately 500 ppm, or approximately 200 to approximately 500 ppm of magnesium metal.

[0071] In one embodiment, a silane-containing compound can be combined with a conventional lubricating oil detergent additive containing lithium. In one embodiment, one or more lithium detergents can be added to the lubricating oil composition in an amount sufficient to provide the composition with 0 to about 2400 ppm of lithium metal, 0 to about 2200 ppm of lithium metal, 100 to about 2000 ppm of lithium metal, 200 to about 1800 ppm of lithium metal, or about 100 to about 1800 ppm, or about 200 to about 1500 ppm, or about 300 to about 1400 ppm, or about 400 to about 1400 ppm of lithium metal.

[0072] In one embodiment, a silane-containing compound can be combined with a conventional lubricating oil detergent additive containing sodium. In one embodiment, one or more sodium detergents can be added to the lubricating oil composition in an amount sufficient to provide the composition with 0 to about 2400 ppm of sodium metal, 0 to about 2200 ppm of sodium metal, 100 to about 2000 ppm of sodium metal, 200 to about 1800 ppm of sodium metal, or about 100 to about 1800 ppm, or about 200 to about 1500 ppm, or about 300 to about 1400 ppm, or about 400 to about 1400 ppm of sodium metal.

[0073] In one embodiment, a silane-containing compound can be combined with a conventional lubricating oil detergent additive containing potassium. In one embodiment, one or more potassium detergents can be added to the lubricating oil composition in an amount sufficient to provide the composition with 0 to about 2400 ppm of potassium metal, 0 to about 2200 ppm of potassium metal, 100 to about 2000 ppm of potassium metal, 200 to about 1800 ppm of potassium metal, or about 100 to about 1800 ppm, or about 200 to about 1500 ppm, or about 300 to about 1400 ppm, or about 400 to about 1400 ppm of potassium metal.

[0074] In one embodiment, the present disclosure provides a lubricating engine oil composition comprising a lubricating oil base as a main component and at least one silane-containing compound as a trace component, wherein the engine exhibits a reduction of more than 50% in low-speed early ignition (LSPI) when compared to the LSPI performance achieved in an engine using a lubricating oil that does not contain at least one silane-containing compound, based on a normalized low-speed early ignition (LSPI) count / 100,000 engine cycles, engine operating speed of 500 to 3,000 revolutions per minute, and net mean effective pressure (BMEP) of 10 to 30 bar.

[0075] In one embodiment, the present disclosure provides a lubricating engine oil composition for use in a boosted mini-engine, comprising a lubricating oil base as a main component and at least one silane-containing compound as a trace component, wherein the mini-engine is in the range of about 0.5 to about 3.6 liters, about 0.5 to about 3.0 liters, about 0.8 to about 3.0 liters, about 0.5 to about 2.0 liters, or about 1.0 to about 2.0 liters. The engine may have two, three, four, five, or six cylinders.

[0076] In one embodiment, the disclosure provides the use of at least one silane-containing compound to prevent or reduce low-speed premature ignition in a boost direct-injection spark-ignition internal combustion engine.

[0077] Lubricant additives In addition to the silane compounds described herein, the lubricating oil composition may include additional lubricating oil additives.

[0078] The lubricating oil compositions of this 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 may be used in the lubricating oil compositions disclosed herein. Several suitable additives are described in Mortier et al., "Chemistry and Technology of Lubricants," 2nd edition, London, Springer, (1996); and Leslie R. Rudnick, "Lubricant Additives: Chemistry and Applications," New York, Marcel Dekker (2003), both of which are incorporated herein by reference. For example, lubricating oil compositions can be blended with antioxidants, anti-wear agents, metal detergents, rust inhibitors, dehazing agents, deemulsifiers, metal deactivators, friction modifiers, pour point depressants, antifoaming agents, cosolvents, corrosion inhibitors, ashless dispersants, multifunctional factors, dyes, extreme pressure agents, etc., and mixtures thereof. Various additives are known and commercially available. These additives or compounds similar thereto can be used in the preparation of the lubricating oil compositions of this disclosure by conventional blending methods.

[0079] The lubricating oil composition of the present invention may contain one or more detergents. The metal-containing or ash-forming detergent has both the function of a detergent for reducing or removing deposits and the function of an acid neutralizer or rust inhibitor, thereby reducing wear and corrosion and extending engine life. The detergent generally comprises a polar head and a long hydrophobic tail. The polar head contains a metal salt of an acidic organic compound. The salt may contain substantially stoichiometric amounts of metal, in which case such salts are usually described as normal salts or neutral salts. A large amount of metal base may be mixed by reacting an excess metal compound (e.g., oxide or hydroxide) with an acidic gas (e.g., carbon dioxide).

[0080] Suitable detergents include oil-soluble neutral and overbasic sulfonates, phenates, phenate sulfides, thiophosphonates, salicylates, and naphthenates, as well as metals, particularly alkali metals or alkaline earth metals, such as barium, sodium, potassium, lithium, calcium, and magnesium, and other oil-soluble carboxylates. 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.

[0081] The lubricating oil composition of the present invention may contain one or more anti-wear agents capable of reducing friction and excessive wear. Any anti-wear agent known to those skilled in the art may be used in the lubricating oil composition. Non-limiting examples of suitable anti-wear agents include zinc dithiophosphate, metal (e.g., Pb, Sb, Mo, etc.) salts of dithiophosphate, metal (e.g., Zn, Pb, Sb, Mo, etc.) salts of dithiocarbamates, metal (e.g., Zn, Pb, Sb, etc.) salts of fatty acids, boron compounds, phosphate esters, phosphite esters, amine salts of phosphate esters or thiophosphate esters, reaction products of dicyclopentadiene and thiophosphate, and combinations thereof. The amount of anti-wear agent may vary from about 0.01% to about 5% by weight, about 0.05% to about 3% by weight, or about 0.1% to about 1% by weight, based on the total weight of the lubricating oil composition.

[0082] In certain embodiments, the anti-wear agent is or comprises a dihydrocarbyl dithiophosphate metal salt, such as a dialkyldithiophosphate zinc compound. The metal of the dihydrocarbyl dithiophosphate metal salt may be an alkali 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 about 3 to about 22 carbon atoms, about 3 to about 18 carbon atoms, about 3 to about 12 carbon atoms, or about 3 to about 8 carbon atoms. In further embodiments, the alkyl group is linear or branched.

[0083] The amount of dihydrocarbyl dithiophosphate metal salts, such as dialkyldithiophosphate zinc salt, in the lubricating oil compositions disclosed herein is determined by their phosphorus content. In some embodiments, the phosphorus content of the lubricating oil compositions disclosed herein is about 0.01% to about 0.14% by weight, based on the total weight of the lubricating oil composition.

[0084] 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 fatty carboxylic acids; derivatives of fatty carboxylic acids (e.g., alcohols, esters, borate esters, amides, metal salts, etc.); mono, di, or trialkyl-substituted phosphoric acid or phosphonic acid; derivatives of mono, di, or trialkyl-substituted phosphoric acid or phosphonic acid (e.g., esters, amides, metal salts, etc.); mono, di, or trialkyl-substituted amines; mono or dialkyl-substituted amides and combinations thereof. In some embodiments, examples of friction modifiers include, but are not limited to, alkoxylated fatty amines; borate fatty epoxides; fatty phosphites, fatty epoxides, fatty amines, borate alkoxylated fatty amines, metal salts of fatty acids, fatty acid amides, glycerol esters, borate glycerol esters; and fatty imidazolines disclosed in U.S. Patent No. 6,372,696, the contents of which are incorporated herein by reference; C4-C 75 Or C6~C 24 Or C6~C 20 Examples include friction modifiers obtained from reaction products of fatty acid esters with nitrogen-containing compounds selected from the group consisting of ammonia and alkanolamines, and mixtures thereof. The amount of friction modifier may vary from about 0.01% to about 10% by weight, about 0.05% to about 5% by weight, or about 0.1% to about 3% by weight, based on the total weight of the lubricating oil composition.

[0085] The lubricating oil composition of this disclosure may contain a molybdenum-containing friction modifier. The molybdenum-containing friction modifier may be any one of a known molybdenum-containing friction modifier or a known molybdenum-containing friction modifier composition.

[0086] Preferred molybdenum-containing friction modifiers include, for example, oxymolybdenum dithiocarbamate sulfide, oxymolybdenum dithiophosphate sulfide, amine-molybdenum complex compounds, oxymolybdenum diethylamide, and oxymolybdenum monoglyceride. The most preferred is the molybdenum dithiocarbamate friction modifier.

[0087] The lubricating oil composition of the present invention generally contains a molybdenum-containing friction modifier in an amount of 0.01 to 0.15% by weight with respect to the molybdenum content.

[0088] The lubricating oil composition of the present invention preferably contains an organic antioxidant in an amount of 0.01 to 5% by weight, preferably 0.1 to 3% by weight. The antioxidant may be a hindered phenol antioxidant or a diarylamine antioxidant. Diarylamine antioxidants are advantageous in that a basic number originating from nitrogen atoms can be obtained. Hindered phenol antioxidants are advantageous in that they do not produce NOx gas. Examples of hindered phenol antioxidants 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), and 4,4'-thiobis(2-methyl-6 Examples include 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 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 Irganox L135® (BASF), Naugalube 531® (Chemtura), and Ethanox 376® (SI Group), but are not limited to these.

[0089] Examples of diarylamine antioxidants include alkyldiphenylamines, p,p-dioctyldiphenylamines, phenyl-naphthylamines, phenyl-naphthylamines, alkylated naltylamines, and alkylated phenyl-naphthylamines, which have a mixture of alkyl groups with 3 to 9 carbon atoms. Diarylamine antioxidants may have 1 to 3 alkyl groups.

[0090] Hindered phenol antioxidants and diarylamine antioxidants can be used individually or in combination. If desired, other oil-soluble antioxidants may be used in combination with the above antioxidants (one or more).

[0091] The lubricating oil composition of the present invention may further contain a succinimide oxymolybdenum complex, particularly a succinimide sulfur-containing oxymolybdenum complex. When used in combination with the above-mentioned phenolic or amine-based antioxidants, the succinimide sulfur-containing oxymolybdenum complex can increase the oxidation inhibition rate.

[0092] In the preparation of lubricating oil formulations, it is customary to introduce additives in the form of concentrates containing 10 to 80% by weight of the active ingredient in a hydrocarbon oil, such as a mineral oil-based lubricant, or other suitable solvent.

[0093] Typically, these concentrates may be diluted in the formation of a finished lubricating oil, such as crankcase motor oil, at a ratio of 3 to 100 parts by weight per part by weight of the additive package, for example, 5 to 40 parts by weight of lubricating oil. Naturally, the purpose of the concentrates is to reduce the difficulty and inconvenience of handling the various materials and to facilitate the dissolution or dispersion of the final blend.

[0094] Method for preparing a lubricating oil composition The lubricating oil compositions disclosed herein can be prepared by any method known to those skilled in the art to manufacture lubricating oils. In some embodiments, the base oil may be blended or mixed with the silane-containing compounds described herein.

[0095] Optionally, one or more other additives may be added in addition to the silane-containing compound. The silane-containing compound and the optional additives may be added to the base oil individually or simultaneously. In some embodiments, the silane-containing compound and the optional additives may be added to the base oil individually in one or more additions, and the additions may be in any order. In other embodiments, the silane-containing compound and the additives may be added to the base oil simultaneously in the form of an additive concentrate. In some embodiments, solubilization of the silane-containing compound or any solid additive in the base oil may be assisted 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.

[0096] Any mixing or dispersion apparatus known to those skilled in the art may be used to blend, mix, or solubilize the components. Blending, mixing, or solubilization can be carried out using a blender, stirrer, disperser, mixer (e.g., planetary mixer and double planetary mixer), homogenizer (e.g., Gaulin homogenizer and Rannie homogenizer), mill (e.g., colloid mill, ball mill and sand mill) or any other mixing or dispersion apparatus known in the art.

[0097] Uses of lubricating oil compositions The lubricating oil compositions disclosed herein may be suitable for use as motor oil (i.e., engine oil or crankcase oil) in spark-ignition internal combustion engines, particularly boost direct injection engines that are susceptible to the effects of low-speed premature ignition.

[0098] The following examples are provided to illustrate embodiments of the present invention and are not intended to limit the invention to the specific embodiments described. Unless otherwise indicated, all parts and percentages are by weight. All numerical values ​​are approximate. Where numerical ranges are given, it should be understood that embodiments outside the specified range are also included within the scope of the invention. The specific details described in each example should not be construed as essential features of the invention. [Examples]

[0099] The following examples are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0100] The test compounds were blended into gasoline or lubricating oil, and their ability to reduce these LSPI events was determined using the following test method.

[0101] A GM2.0 L LHU 4-cylinder gasoline turbocharged direct injection engine was used for the LSPI test. Each cylinder was equipped with a combustion pressure sensor.

[0102] A test procedure divided into six sections was used to determine the number of LSPI events that occurred under the conditions of an engine speed of 2000 rpm and a load of 275 Nm. The LSPI test conditions were run for 28 minutes, with each section divided into pauses. Each section was slightly shortened to eliminate transients. Each shortened section typically has approximately 110,000 combustion cycles (27,500 combustion cycles per cylinder). In total, the six shortened sections have approximately 660,000 combustion cycles (165,000 combustion cycles per cylinder).

[0103] LSPI-affected combustion cycles were determined by monitoring the crank angle at peak in-cylinder pressure (PP) and total heat dissipation (AI5) at 5%. An LSPI-affected combustion cycle is defined as having both (1) a PP greater than 5 standard deviations above the average PP for a given cylinder and shortened section, and (2) an AI5 greater than 5 standard deviations below the average for a given cylinder and shortened section.

[0104] The frequency of LSPI occurrences is reported as the number of LSPI-affected combustion cycles per million combustion cycles, and is calculated as follows: LSPI occurrence frequency = [(Total number of combustion cycles affected by LSPI in the 6 shortened periods) / (Total number of combustion cycles in the 6 shortened periods)] × 1,000,000

[0105] Additives associated with test lubricants that reduce the frequency of LSPI are considered to be additives that reduce the frequency of LSPI when compared to the corresponding reference lubricant. The test results are shown in Table 1.

[0106] Standard formulation The standard formulation contained a Group 2 base oil, a mixture of primary and secondary dialkylzinc dithiophosphates in an amount that supplied 741-814 ppm of phosphorus to the lubricating oil composition, a mixture of polyisobutenyl succinimide dispersants (borate-treated and ethylene carbonate post-treated), a molybdenum succinimide complex in an amount that supplied 177-187 ppm of molybdenum to the lubricating oil composition, an alkylated diphenylamine antioxidant, a borate friction modifier, an antifoaming agent, a pour point depressant, and an olefin copolymer viscosity index improver. The standard formulation contained approximately 5 ppm of silicon derived from the antifoaming agent.

[0107] The lubricating oil compositions were blended to obtain an oil with a viscosity grade of 5W-30.

[0108] Silane compound A Silane compound A is a commercially available silane compound with chemical formula C 18 H 42 It was O6S2Si bis[3-(triethoxysilyl)propyl] disulfide.

[0109] (Example 1) A lubricating oil composition was prepared by adding silicon (approximately 1087 ppm) derived from silane-containing compound A and calcium (2456 ppm) derived from a combination of overbasic Ca sulfonate and phenate detergent to a standard formulation.

[0110] (Comparative Example 1) A lubricating oil composition was prepared by adding calcium (2399 ppm) derived from a combination of overbasic Ca sulfonate and phenate detergent to a standard formulation.

[0111] (Example 2) A lubricating oil composition was prepared by adding silicon (approximately 993 ppm) derived from silane-containing compound A and calcium (2221 ppm) derived from a combination of overbasic Ca sulfonate and phenate detergent to a standard formulation.

[0112] (Example 3) A lubricating oil composition was prepared by adding silicon (approximately 520 ppm) derived from silane-containing compound A and calcium (2218 ppm) derived from a combination of overbasic Ca sulfonate and phenate detergent to a standard formulation.

[0113] (Example 4) A lubricating oil composition was prepared by adding silicon (approximately 262 ppm) derived from silane-containing compound A and calcium (2222 ppm) derived from a combination of overbasic Ca sulfonate and phenate detergent to a standard formulation.

[0114] (Comparative Example 2) A lubricating oil composition was prepared by adding calcium (2255 ppm) derived from a combination of overbasic Ca sulfonate and phenate detergent to a standard formulation.

[0115] [Table 1]

[0116] The data demonstrate that the present applicant's example of the present invention, which includes a silane compound, resulted in significantly better LSPI performance.

[0117] Low-speed premature ignition events were also measured in the Ford 2.0L Ecoboost engine, which is a turbocharged direct-injection (GDI) gasoline engine.

[0118] The Ford Ecoboost engine is run in four iterations of approximately four hours each. The engine is operated at an oil reservoir temperature of 95°C, 1750 rpm, and a net mean effective pressure (BMEP) of 1.7 MPa. The engine is run for 175,000 combustion cycles in stages, and LSPI events are counted.

[0119] LSPI events are determined by monitoring the peak in-cylinder pressure (PP) and the mass combustion ratio (MFB) of the fuel filled in the cylinder. An LSPI event can be considered to have occurred if either or both of the criteria are met. The peak in-cylinder pressure threshold varies from test to test, but is typically 4–5 standard deviations higher than the average in-cylinder pressure. Similarly, the MFB threshold is typically 4–5 standard deviations earlier than the average MFB (expressed in crank angle). LSPI events can be reported as the average number of events per test, the number of events per 100,000 combustion cycles, the number of events per cycle, and / or the number of combustion cycles per event. The results of this test are shown below. [Table 2]

[0120] The data show that the applicant's example of the present invention, which includes the silane compound of this disclosure, yielded significantly better LSPI performance in terms of both the number of events and, furthermore, the number of severe LSPI events, compared to a comparative example that does not include the silane compound in the Ford engine. Severity is reduced by reducing the number of high-pressure events (i.e., above 120 bar) that could damage the engine.

Claims

1. A method for preventing or reducing low-speed premature ignition in a boost direct-injection spark-ignition internal combustion engine, comprising the step of lubricating the crankcase of the engine with a lubricating oil composition containing about 100 to about 3000 ppm of silicon derived from at least one silane-containing compound, based on the total weight of the lubricating oil composition.

2. The method according to claim 1, wherein the engine is operated under a load of approximately 12 to approximately 30 bar net mean effective pressure (BMEP).

3. The method according to claim 1, wherein the engine is operated at a speed of 500 to 3000 rpm.

4. The silane-containing compound is defined by the following general formula (I): [(R １ ) ３－ａ (R ２ O) ａ Si] ｒ A (I) (In the formula, R １ R is selected from the group consisting of saturated and unsaturated hydrocarbyl and chain-substituted saturated and unsaturated hydrocarbyl, ２ (a) is selected from the group consisting of hydrogen, saturated and unsaturated hydrocarbyl groups and chain-substituted saturated and unsaturated hydrocarbyl groups, a is an integer from 1 to 3, and A is a group with a valence r (r is an integer of 1 or more), selected from the group consisting of saturated and unsaturated linear, branched or cyclic hydrocarbyl groups, an oxygen atom, or linear, branched or cyclic siloxane or polysiloxane groups (each of which, except for the oxygen atom, may optionally include substituents having oxygen, nitrogen, sulfur, or a halogen heteroatom). The method according to claim 1, comprising:

5. The method according to claim 1, wherein the lubricating oil further comprises a detergent selected from calcium detergent, magnesium detergent, sodium detergent, lithium detergent, and potassium detergent.

6. The method according to claim 5, wherein the detergent is a carboxylate, salicylate, phenate, or sulfonate detergent.

7. The method according to claim 1, wherein the lubricating oil further comprises a molybdenum-containing compound.

8. The method according to claim 1, wherein the lubricating oil composition further comprises at least one other additive selected from ashless dispersants, ashless antioxidants, phosphorus-containing anti-wear additives, friction modifiers, and polymer viscosity modifiers.

9. The method according to claim 1, wherein the engine is fueled with a liquid hydrocarbon fuel, a liquid non-hydrocarbon fuel, or a mixture thereof.

10. The method according to claim 1, wherein the engine is fueled by natural gas, liquefied petroleum gas (LPG), compressed natural gas (CNG), or a mixture thereof.

11. Use of at least one silane-containing compound in a lubricating engine oil composition to prevent or reduce low-speed premature ignition in a boost direct injection spark-ignition internal combustion engine.

12. The use according to claim 11, wherein the at least one silane-containing compound is present in an amount of silicon derived from the at least one silane-containing compound at a concentration of about 100 to about 3000 ppm, based on the total weight of the lubricating oil composition.

13. A lubricating engine oil composition for use in a boost small engine, comprising a lubricating oil base material as the main component and at least one silane-containing compound as a trace component, wherein the small engine is in the range of 0.5 liters to 3.6 liters.

14. The silane-containing compound is defined by the following general formula (I): [(R １ ) ３－ａ (R ２ O) ａ Si] ｒ A (I) (In the formula, R １ R is selected from the group consisting of saturated and unsaturated hydrocarbyl and chain-substituted saturated and unsaturated hydrocarbyl, ２ (a) is selected from the group consisting of hydrogen, saturated and unsaturated hydrocarbyl groups and chain-substituted saturated and unsaturated hydrocarbyl groups, a is an integer from 1 to 3, and A is a group with a valence r (r is an integer of 1 or more), selected from the group consisting of saturated and unsaturated linear, branched or cyclic hydrocarbyl groups, an oxygen atom, or linear, branched or cyclic siloxane or polysiloxane groups (each of which, except for the oxygen atom, may optionally include substituents having oxygen, nitrogen, sulfur, or a halogen heteroatom). The lubricating oil composition according to claim 13, having the following characteristics.

Images