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

Abstract

To provide an improved lubricating composition effective for preventing or reducing low-speed pre-ignition in an engine and for preventing or reducing corrosion of engine components.SOLUTION: A lubricating composition comprises a base oil combined with a cyclic calcium chelate complex, and optionally further comprises an additional additive.SELECTED DRAWING: None

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 62 / 815,795, filed March 8, 2019, the contents of which are incorporated herein in their entirety.

[0002] This disclosure relates to lubricant compositions containing at least one calcium cyclic chelate complex, such as calcium chelates of 1,3-dicarbonyl compounds, ortho-ketophenols, 1,3-diimines, mixed chelates, and combinations thereof. The disclosure also relates to lubricant compositions containing at least one calcium cyclic chelate complex for direct injection, boosted, spark-ignition internal combustion engines. This disclosure also relates to methods for preventing or reducing low-speed pre-ignition in engines lubricated with formulated oils. The formulated oils have compositions containing at least one oil-soluble or oil-dispersible calcium cyclic chelate complex. [Background technology]

[0003] In recent years, engine manufacturers have developed smaller engines that offer higher power density and superior performance while reducing friction and pumping losses. This is achieved by slowing the engine down by increasing boost pressure using turbochargers or mechanical superchargers and by using higher transmission ratios, which allows for higher torque generation at lower engine speeds. However, higher torque at lower engine speeds has been found to cause random pre-ignition in the engine at low speeds, a phenomenon known as Low Speed ​​Pre-Ignition (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 lower engine speeds in these smaller, high-power engines.

[0004] One of the leading theories surrounding the cause of low-speed pre-ignition (LSPI) is that it is due, at least in part, to the auto-ignition of engine oil droplets entering the engine combustion chamber through the piston gap under high pressure when the engine is operating at low speeds and the compression stroke is at its longest (Amann et al. SAE 2012-01-1140).

[0005] Although some engine knocking and pre-ignition problems can and have been solved through new engine technology, such as the use of electronic controls and knock sensors, and through optimization of 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.

[0006] The present inventors have discovered a solution to address the problem of LSPI through the use of calcium cyclic chelate complexes, such as calcium chelates of 1,3-dicarbonyl compounds, ortho-ketophenols, 1,3-diimines, mixed chelates, and combinations thereof. Summary of the Invention

[0007] Lubricating oil additives that reduce or eliminate low-speed pre-ignition are disclosed herein. Suitable additives include calcium cyclic chelate complexes, such as calcium chelates containing one or more multidentate compounds, such as 1,3-dicarbonyl compounds, ortho-ketophenols, 1,3-diimines, and the like.

[0008] The details of one or more embodiments are set forth in the detailed description below. Other features, objects, and advantages will be apparent from the detailed description, and from the claims. DETAILED DESCRIPTION OF THE INVENTION

[0009] Before the present methods and systems are disclosed and described, it is to be understood that the methods and systems are not limited to specific synthetic methods, specific components, or particular compositions. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.

[0010] As used in the specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from "about" one particular value, and / or to "about" another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values ​​are expressed as approximations, by use of the antecedent "about," it will be understood that the particular value forms another embodiment. It will be further understood that each endpoint of a range is significant both in relation to the other endpoint, and independently of the other endpoint.

[0011] "Optional" or "optionally" means that the subsequently described event or circumstance may or may not occur, and that the detailed description includes instances where the event or circumstance occurs and instances where the event or circumstance does not occur.

[0012] Throughout this specification and the claims, the word "comprise" and variations of that word, such as "comprising" and "comprises," mean "including but not limited to," and are not intended to exclude, for example, other additives, components, integers, or steps. "Exemplary" means "an example of," and is not intended to convey an indication of a preferred or ideal embodiment. "For example," "for example," is used for illustrative purposes, not for limiting purposes.

[0013] Disclosed are components that can be used to implement the disclosed methods and systems. These and other components are disclosed herein, and it is understood that combinations, subsets, interactions, groups, etc. of these components, when disclosed, are each specifically contemplated and described herein with respect to all methods and systems, even if specific reference to each of their various individual and collective combinations and permutations may not be expressly disclosed. This applies to all aspects of this application, including, but not limited to, steps in the disclosed methods. Thus, when there are various additional steps that may be implemented, it is understood that each of these additional steps may be implemented by any specific embodiment or combination of embodiments of the disclosed methods.

[0014] The term "boosting" is used throughout the specification. Boosting refers to running an engine at a higher intake pressure than in a naturally aspirated engine. Boost conditions can be achieved through the use of a turbocharger (driven by the exhaust) or a supercharger (driven by the engine). "Boosting" allows engine manufacturers to use smaller engines that deliver higher power density for superior performance while reducing friction and pumping losses.

[0015] The terms oil-soluble or oil-dispersible are used throughout the specification and claims. Oil-soluble or oil-dispersible means that the amount needed to impart the desired level of activity or performance can be incorporated by dissolving, dispersing, or suspending in an oil of lubricating viscosity. Typically, this means that at least about 0.001 wt. % of the material can be incorporated into a lubricating oil composition. For further discussion of oil-soluble or oil-dispersible, and particularly the term "stably dispersible," see U.S. Pat. No. 4,320,019, which is expressly incorporated herein by reference for its relevant teachings in this regard.

[0016] The term "sulfated ash" as used herein refers to non-burnable residues resulting from detergent and metal additives in lubricating oils. Sulfated ash may be determined using ASTM test D874.

[0017] The term "Total Base Number" or "TBN," as used herein, refers to the amount of base equivalent to milligrams of KOH in one gram of sample. Thus, a higher TBN number indicates more alkaline products and, therefore, higher alkalinity. TBN was determined using the ASTM D 2896 test.

[0018] Unless otherwise specified, all percentages are in weight percent.

[0019] Generally, the sulfur level in the lubricating oil compositions of the present invention is about 0.7 wt.% or less, based on the total weight of the lubricating oil composition, e.g., sulfur levels of about 0.01 wt.% to about 0.70 wt.%, 0.01 wt.% to 0.6 wt.%, 0.01 wt.% to 0.5 wt.%, 0.01 wt.% to 0.4 wt.%, 0.01 wt.% to 0.3 wt.%, 0.01 wt.% to 0.2 wt.%, or 0.01 wt.% to 0.10 wt.%. In one embodiment, the sulfur level in the lubricating oil compositions 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.

[0020] In one embodiment, the phosphorus level in the lubricating oil composition of the present invention is about 0.12 wt. % or less, for example, from about 0.01 wt. % to about 0.12 wt. %. In one embodiment, the phosphorus level in the lubricating oil composition of the present invention is about 0.11 wt. % or less, for example, from about 0.01 wt. % to about 0.11 wt. %. In one embodiment, the phosphorus level in the lubricating oil composition of the present invention is about 0.10 wt. % or less, for example, from about 0.01 wt. % to about 0.10 wt. %. In one embodiment, the phosphorus level in the lubricating oil composition of the present invention is about 0.09 wt. % or less, for example, from about 0.01 wt. % to about 0.09 wt. %. In one embodiment, the phosphorus level in the lubricating oil composition of the present invention is about 0.08 wt. % or less, for example, from about 0.01 wt. % to about 0.08 wt. % based on the total weight of the lubricating oil composition. In one embodiment, the phosphorus level in the lubricating oil composition of the present invention is about 0.07 wt. % or less, for example, from about 0.01 wt. % to about 0.07 wt. % based on the total weight of the lubricating oil composition. In one embodiment, the phosphorus level in the lubricating oil composition of the present invention is about 0.05 wt. % or less, for example, from about 0.01 wt. % to about 0.05 wt. % based on the total weight of the lubricating oil composition.

[0021] 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, for example, the sulfated ash level is about 0.10 to about 1.60 wt. % 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, for example, the sulfated ash level is about 0.10 to about 1.00 wt. % 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, for example, the sulfated ash level is about 0.10 to about 0.80 wt. % 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, the sulfated ash level is from about 0.10 to about 0.60 wt. % as determined by ASTM D 874.

[0022] Suitably, the lubricating oil composition may have a total base number (TBN) of 4 to 15 mgKOH / g (e.g., 5 to 12 mgKOH / g, 6 to 12 mgKOH / g, or 8 to 12 mgKOH / g). Low-speed pre-ignition is most likely to occur in direct-injection boosted (turbocharged or supercharged), spark-ignition (gasoline) internal combustion engines operating at engine speeds of about 1500 to about 2500 revolutions per minute (rpm), e.g., about 1500 to about 2000 rpm, and generating a brake mean effective pressure level of greater than about 15 bar (peak torque), e.g., at least about 18 bar, particularly at least about 20 bar. As used herein, brake mean effective pressure (BMEP) is defined as the work accomplished during one engine cycle divided by the engine's swept volume, and engine torque is normalized by engine displacement. The term "net (brake)" refers to the actual torque / power available at the engine's flywheel as measured by a dynamometer. BMEP is therefore a measure of the engine's useful power output.

[0023] In one embodiment of the invention, the engine is operated at a speed between 500 and 3000 rpm, or 800 rpm to 2800 rpm, or even 1000 rpm to 2600 rpm. Additionally, the engine may be operated at a brake mean effective pressure of 10 bar to 30 bar, or 12 bar to 24 bar.

[0024] Although LSPI events are relatively rare, they can be catastrophic in nature. Therefore, 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 is configured to achieve less than 150 LSPI events per million combustion cycles (which may also be expressed as 15 LSPI events per 100,000 combustion cycles), or less than 100 LSPI events per million combustion cycles, or less than 70 LSPI events per million combustion cycles, or less than 60 LSPI events per million combustion cycles, or less than 50 LSPI events per million combustion cycles, or less than 40 LSPI events per million combustion cycles, or less than 30 LSPI events per million combustion cycles, or less than 20 LSPI events per million combustion cycles, or less than 10 LSPI events per million combustion cycles, or even 0 LSPI events per million combustion cycles.

[0025] 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, comprising lubricating the crankcase of the engine with a lubricating oil composition comprising at least one calcium cyclic chelate complex. In one embodiment, the amount of metal from the at least one calcium cyclic chelate complex in the lubricating oil composition is from about 100 to about 3,000 ppm, from about 200 to about 3,000 ppm, from about 250 to about 2,500 ppm, from about 300 to about 2,500 ppm, from about 350 to about 2,500 ppm, from about 400 to about 2,500 ppm, from about 500 to about 2,500 ppm, from about 600 to about 2,500 ppm, from about 700 to about 2,500 ppm, from about 700 to about 2,000 ppm, or from about 700 to about 1,500 ppm. In one embodiment, the amount of metal from the calcium cyclic chelate complex is about 2000 ppm or less, or 1500 ppm or less in the lubricating oil composition. In one particular embodiment, the lubricating composition does not contain any calcium salicylate compounds.

[0026] 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 oil that does not contain at least one calcium cyclic chelate complex.

[0027] 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, comprising lubricating the engine's crankcase with a lubricating oil composition comprising at least one calcium cyclic chelate complex. LSPI events are determined by monitoring peak cylinder pressure (PP) and mass fraction of fuel burned (MFB) in the cylinder. An LSPI event can be said to have occurred when either or both criteria are met. The peak cylinder pressure threshold varies by test but is typically 4 to 5 standard deviations above the mean cylinder pressure. Similarly, the MFB threshold is typically 4 to 5 standard deviations earlier than the mean MFB (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. In one embodiment, the number of LSPI events where both the MFB02 and peak pressure (PP) requirements were above 90 bar pressure was 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. In one embodiment, the number of LSPI events above 90 bar was zero events, or in other words, fully suppressed LSPI events above 90 bar. In one embodiment, the number of LSPI events where both the MFB02 and peak pressure (PP) requirements were above 100 bar pressure was less than 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 event per 100,000 combustion cycles. In one embodiment, the number of LSPI events above 100 bar was zero events, or in other words, fully suppressed LSPI events above 100 bar.In one embodiment, the number of LSPI events where both the MFB02 and peak pressure (PP) requirements were at pressures above 110 bar was less than 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 event per 100,000 combustion cycles. In one embodiment, the number of LSPI events above 110 bar was zero events, or in other words, fully suppressed LSPI events above 110 bar. For example, the number of LSPI events where both the MFB02 and peak pressure (PP) requirements were above 120 bar pressure was 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. In one embodiment, the number of LSPI events above 120 bar was zero events, or in other words, very severe LSPI events (i.e., events above 120 bar) that were completely suppressed.

[0028] It has now been discovered that the occurrence of LSPI in an engine prone to LSPI can be reduced by lubricating such an engine with a lubricating oil composition containing a calcium cyclic chelate complex. Calcium species, such as calcium-based detergents, are known to cause LSPI, and the ability of the disclosed cyclic calcium chelate complex to reduce LSPI was previously unknown and unexpected.

[0029] The present disclosure further provides a method as described herein for injecting a liquid hydrocarbon fuel, a liquid non-hydrocarbon fuel, or a mixture thereof into an engine.

[0030] The present disclosure further provides a method as described herein, wherein the engine is injected with natural gas, liquefied petroleum gas (LPG), compressed natural gas (CNG), or a mixture thereof.

[0031] Lubricating oil compositions suitable for use as passenger car motor oils conventionally comprise a major amount of oil of lubricating viscosity and minor amounts of performance-enhancing additives, including ash-containing compounds. Advantageously, the metals described herein are introduced into the lubricating oil compositions used in the practice of this disclosure by one or more calcium cyclic chelate complexes.

[0032] Oil / base oil composition of lubricating viscosity The oil of lubricating viscosity used in the lubricating oil compositions of this 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 to about 99.5 wt. %, and most preferably about 85 to about 98 wt. %, based on the total weight of the composition. The term "base oil," as used herein, is understood to mean a base stock or blend of base stocks that is a lubricant component manufactured to the same specifications by a single manufacturer (regardless of source or location of manufacturer) and meeting the same manufacturer's specifications, and identified by a unique formulation, product identification number, or both. Base oils, as used herein, can be any now known or later discovered oil of lubricating viscosity used to formulate lubricating oil compositions for any and all such applications, such as engine oils, marine cylinder oils, functional fluids, e.g., hydraulic oils, gear oils, transmission fluids, and the like. In addition, the base oils used herein may optionally contain viscosity index improvers, such as polymeric alkyl methacrylates; olefinic copolymers, such as ethylene-propylene copolymers or styrene-diene copolymers; and the like, and mixtures thereof.

[0033] As one skilled in the art will readily appreciate, the viscosity of a base oil will depend on the intended use. Accordingly, the viscosity of base oils used herein typically ranges from about 2 to about 2000 centistokes (cSt) at 100° C. Generally, base oils used as engine oils will have kinematic viscosities ranging from about 2 to about 30 cSt at 100° C., preferably from about 3 to about 16 cSt, and most preferably from about 4 to about 12 cSt, and are selected or blended depending on the desired end use and additives in the finished oil to produce a desired grade of engine oil, e.g., 0W, 0W-4, 0W-8, 0W-12, 0W-16, 0W-18, 0W-20, 0W-22, 0W-24, 0W-26, 0W-28, 0W-29, 0W-30, 0W-31, 0W-32, 0W-33, 0W-34, 0W-35, 0W-36, 0W-37, 0W-38, 0W-39, 0W-40, 0W-41, 0W-42, 0W-43, 0W-44, 0W-45, 0W-46, 0W-47, 0W-48, 0W-49, 0W-50, 0W-51, 0W-52, 0W-53, 0W-54, 0W-55, 0W-56, 0W-57, 0W-58, 0W-59, 0W-60, 0W-61, 0W-62, 0W-63, 0W-64, 0W-65, 0W-66, 0W-67 Lubricating oil compositions having SAE viscosity grades such as 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 provided.

[0034] Group I base oil generally refers to petroleum-derived lubricating base oils having a saturates content of 90 weight percent (as determined by ASTM D 2007) and / or a total sulfur content of greater than 300 ppm (as determined by ASTM D 2622, ASTM D 4294, ASTM D 4297, or ASTM D 3120), and having a viscosity index (VI) of 80 or greater and 120 or less (as determined by ASTM D 2270).

[0035] Group II base oil generally refers to a petroleum-derived lubricating base oil having a total sulfur content of less than or equal to 300 parts per million (ppm) (as determined by ASTM D 2622, ASTM D 4294, ASTM D 4927, or ASTM D 3120), a saturates content of greater than or equal to 90 weight percent (as determined by ASTM D 2007), and a viscosity index (VI) between 80 and 120 (as determined by ASTM D 2270).

[0036] Group III base oil generally refers to petroleum derived lubricating base oils having less than 300 ppm sulfur, a saturates content greater than 90 weight percent, and a VI of 120 or greater.

[0037] Group IV base oils are polyalphaolefins (PAOs).

[0038] Group V base oils include all other base oils not included in Group I, II, III, or IV.

[0039] 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 stocks obtained by isomerization of synthetic wax and slack wax, and hydrocracked base stocks produced by hydrocracking (rather than solvent extraction) of the aromatic and polar components of crude oil.

[0040] Suitable natural oils include mineral lubricating oils, such as liquid petroleum oils, solvent-treated or acid-treated mineral lubricating oils of the paraffinic, naphthenic, or mixed paraffinic-naphthenic type, oils derived from coal or shale, animal oils, vegetable oils (e.g., rapeseed oil, castor oil, and lard oil), and the like.

[0041] Suitable synthetic lubricating oils include, but are not limited to, hydrocarbon oils and halo-substituted hydrocarbon oils, such as polymerized or copolymerized olefins, such as polybutylene, polypropylene, propylene-isobutylene copolymers, chlorinated polybutylene, poly(1-hexene), poly(1-octene), poly(1-decene), and the like, and mixtures thereof; alkylbenzenes, such as dodecylbenzene, tetradecylbenzene, dinonylbenzene, di(2-ethylhexyl)-benzene, and the like; polyphenyls, such as biphenyls, terphenyls, alkylated polyphenyls, and the like; alkylated diphenyl ethers and alkylated diphenyl sulfides, and their derivatives, analogs, and homologs.

[0042] 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.

[0043] Further synthetic hydrocarbon oils include liquid polymers of alpha olefins having the appropriate viscosity. Particularly useful synthetic hydrocarbon oils are C6 to C8 12 and hydrogenated liquid oligomers of alpha olefins, such as 1-decene trimer.

[0044] Another class of synthetic lubricating oils includes, but is not limited to, alkylene oxide polymers, i.e., homopolymers, interpolymers, and derivatives thereof where 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, 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 to 1,000, diethyl ether of polypropylene glycol having a molecular weight of 1,000 to 1,500, etc.), or their mono- and polycarboxylic acid esters, such as acetate esters, mixed C3-C8 fatty acid esters, or C6-C8 fatty acid esters of tetraethylene glycol. 13 Examples include oxo acid diesters.

[0045] Yet another class of synthetic lubricating oils includes, but is not limited to, the esters of dicarboxylic acids such as phthalic acid, succinic acid, alkylsuccinic acids, alkenylsuccinic acids, maleic acid, azelaic acid, suberic acid, sebacic acid, fumaric acid, adipic acid, linoleic acid dimer, malonic acid, alkylmalonic acids, alkenylmalonic acids, and the like, with various alcohols such as 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 esters formed by reacting 1 mole of sebacic acid with 2 moles of tetraethylene glycol and 2 moles of 2-ethylhexanoic acid, and the like.

[0046] Esters useful as synthetic oils also include, but are not limited to, those made from carboxylic acids having from about 5 to about 12 carbon atoms with alcohols such as methanol, ethanol, and the like, polyols and polyol ethers such as neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol, tripentaerythritol, and the like.

[0047] Silicon-based oils, such as polyalkyl-, polyaryl-, polyalkoxy-, or polyaryloxy-siloxane oils and silicate oils, comprise another useful class of synthetic lubricating oils. Specific examples include, but are not limited to, tetraethyl silicate, tetraisopropyl silicate, tetra(2-ethylhexyl) silicate, tetra(4-methylhexyl) 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, and the diethyl ester of decanephosphine acid, and polymeric tetrahydrofurans.

[0048] Lubricating oils can be derived from unrefined, refined, and re-refined oils, which are either natural, synthetic, or a mixture of two or more of any of the types disclosed hereinabove. Unrefined oils are those obtained directly from natural or synthetic sources (e.g., coal, shale, or tar sand bitumen) without further refining or processing. Examples of unrefined oils include, but are not limited to, shale oil obtained directly from retorting operations, petroleum oil obtained directly from distillation, or ester oil obtained directly from an esterification process, each of which is subsequently used without further processing. Refined oils are similar to unrefined oils except that they have been further processed in one or more purification 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, hydrotreating, dewaxing, etc. Re-refined oils are obtained by treating used oils in processes similar to those used to obtain refined oils. Such re-refined oils are also known as reclaimed or reprocessed oils and are often additionally processed by techniques directed to removal of spent additives and oil breakdown products.

[0049] Lubricating oil base stocks derived from the hydroisomerization of wax may also be used, either alone or in combination with the above-mentioned natural and / or synthetic base stocks. Such wax isomerate oil is produced by the hydroisomerization of natural or synthetic waxes or mixtures thereof over a hydroisomerization catalyst.

[0050] Natural waxes are typically slack waxes recovered by the solvent dewaxing of mineral oils, while synthetic waxes are typically waxes produced by the Fischer-Tropsch process.

[0051] Other useful fluids of lubricating viscosity include unconventional or unconventional base stocks that have been processed, preferably catalytically processed or synthetically, to impart high performance lubricating properties.

[0052] As used herein, a calcium cyclic chelate complex is a compound having at least one ring formed by the interaction of a calcium ion and a polydentate ligand. As used herein, a polydentate ligand is a compound having at least two Lewis base atoms capable of associating with the same calcium ion. Lewis base atoms include oxygen, nitrogen, sulfur, and phosphorus. A complex between a calcium ion and two Lewis base atoms in the same ligand may be referred to as a bidentate complex, while a complex between a calcium ion and a compound having three Lewis base atoms in the same ligand may be referred to as a tridentate complex. In some cases, the chelate ring complex may have the formula: [ka] During the ceremony: [ka] represents a single or double bond, provided that the valence is satisfied; Y in each case is O, S, NR n1 are independently selected from Z in each occurrence is O, S, NR n2 are independently selected from R 1 , R 2 , R 3 , R n1 , and R n2 is R a , OR b , and N(R b )2 are independently selected from where R a In each case, hydrogen, C 1-8 Alkyl, C 2-8 Alkenyl, C 2-8 Alkynyl, aryl, C 1-8 Heteroaryl, C 3-8 Cycloalkyl, or C 1-8 heterocyclyl; R b In each case, C 1-8 Alkyl, C 2-8 Alkenyl, C 2-8 Alkynyl, aryl, C 1-8 Heteroaryl, C 3-8 Cycloalkyl, or C 1-8 heterocyclyl; where R 1 , R 2 , R 3 , R n1 , and R n2 two or more of which may be joined together to form a ring; It can be a compound having the formula:

[0053] Those skilled in the art will recognize that the calcium chelates shown above can be associated with one or more monodentate ligands to provide charge balance, satisfy the valence requirements of the calcium atom, and / or saturate its coordination sphere. Exemplary such ligands include ionic species, such as hydroxides, halides, carboxylates, and bicarbonates; and nonionic species, such as water, carboxylic acids, amines, primary amines, secondary amines, tertiary amines, and ammonia. The cyclic calcium chelate complexes disclosed herein may be associated with nonionic and / or ionic monodentate ligands, depending on the molecular structure of the chelate and on the other chemical compounds present in the lubricating composition. Unless specified to the contrary, any designation of a cyclic calcium chelate complex neither excludes nor requires the presence of one or more monodentate ligands.

[0054] As used herein, a mixed chelate is a complex in which Y and Z are not the same heteroatom.

[0055] Those skilled in the art will appreciate that the chelate complexes shown above may, for example, be in equilibrium with two or more tautomeric species (defined herein as compounds that differ only at the location of the double bond and acidic proton). For example, a chelate may have various tautomeric forms: [ka]

[0056] The ratio of the individual tautomeric species is Y, Z, R 1 , R 2 , and R 3 The specific nature of R will depend not only on the specific characteristics of the lubricating composition in which the complex is placed, but also on the specific features of the lubricating composition in which it is placed. Furthermore, either Y or Z may be protonated depending on the molecular composition of the chelate and the local environment. 1 , R 2 , R 3Additional tautomeric species may exist, depending on the specific nature of , Y, and Z. Unless expressly stated to the contrary, the representation of one tautomer is not intended to exclude any other possible tautomers or to require the further existence of the specifically represented tautomeric species.

[0057] In certain embodiments, the chelate complex is a six-membered complex, and Y and Z are each oxygen: [ka] In the formula, R 1 , R 2 , and R 3 has the meaning given above. In the equilibrium shown above, sp 3 Although the hybridized oxygen is shown without hydrogen atoms, one skilled in the art will understand that such atoms may be present in certain circumstances. Depending on the specific conditions, the calcium atom may be further substituted by one or more monodentate ligands.

[0058] In certain embodiments, the chelate complex is a six-membered complex, and Y and Z are each nitrogen: [ka] In the formula, R 1 , R 2 , R 3 , R n1 , and R n2 has the meaning given above. In the equilibrium shown above, sp 3 Although the hybridized nitrogen is shown without a hydrogen atom, one skilled in the art will understand that such an atom may be present in certain circumstances. Depending on the specific conditions, the calcium atom may be further substituted by one or more monodentate ligands.

[0059] In still further embodiments, the chelate complex is a six-membered mixed chelate complex, where one of Y and Z is oxygen and the other is nitrogen: [ka] In the formula, R 1 , R 2 , R 3 , R n1 , and R n2 has the meaning given above. In the equilibrium shown above, sp 3 Although the hybrid atoms are shown without hydrogen atoms, one skilled in the art will understand that such atoms may be present in certain circumstances. Depending on the specific conditions, the calcium atom may be further substituted by one or more monodentate ligands.

[0060] In some embodiments, R 1 and R 3 are respectively, C 1-8 is an alkyl group, and R 2 (if present) is hydrogen. 1-8 Alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-butyl, and tert-butyl. 1-8 Alkyl groups may be independently substituted one or more times. Suitable substituents include, but are not limited to, alkoxy, alkenyl, alkynyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, aldehyde, amino, carboxylic acid, ester, ether, halide, hydroxy, ketone, nitro, silyl, sulfo-oxo, phosphine, or thiol.

[0061] In some embodiments of the present invention, R 1 is O.C. 1-8 alkyl, for example, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, iso-butoxy, or tert-butoxy; R 3 is C 1-8Alkyl, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and tert-butyl. 1-8 The alkyl group is, as shown above, C 1-8 In some cases, R 2 is C 1-8 alkyl, and R 1 and R 3 Exemplary five- and six-membered complexes are shown below: [ka] [Table 1-1] [Table 1-2] [Table 1-3]

[0062] In some embodiments, the chelate complex comprises one or more ortho-ketophenol ligands, for example, a ligand of the formula: [ka] The compound may include a complex having the formula: In the formula, R 2a , R 2b , R 2c , and R 2d is hydrogen; hydroxy; C 1-22 Alkyl, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl; OC 1-22 alkyl, e.g., methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, iso-butoxy, or tert-butoxy; where R1 , R 2a , R 2b , R 2c , and R 2d Any two or more of may be taken together to form a ring. In certain embodiments, R 2a , R 2b , R 2c , and R 2d may be hydrogen, while in the other, R 2a In some cases, the keto-phenol is R 1 is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and tert-butyl, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, or tert-butoxy. In certain preferred embodiments, Y and Z are each oxygen; however, as used herein, the term ortho-ketophenol also refers to phenols such as those in which Y is NR n1 In some cases, the keto-phenol ligand may be further substituted once: [ka] In the formula, R k are hydroxyl, amino, C 1-22 Alkyl, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-butyl, and tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl; and OC 1-22 Alkyl, for example, selected from methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, iso-butoxy, or tert-butoxy.

[0063] In certain embodiments, the complex has the formula: [ka] where n is 0, 1 or 2; R 4a , R 4a’ , R 4b , R 4b’ , R 4c , R 4c’ , R 4d , R 4d’ , R 4e , and R 4e’ is hydrogen; hydroxy; C 1-22 Alkyl, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl; C 1-22 O-alkyl, for example, independently selected from methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, iso-butoxy, or tert-butoxy; 4a , R 4a’ , R 4b , R 4b’ , R 4c , R 4c’ , R 4d , R 4d’ , R 4e , and R 4e’ In certain embodiments, R 4c and R 4c’ may each be either hydroxyl or amino, and in further embodiments, R 4b and R 4b’ are each methoxy. In certain preferred embodiments, Y and Z are each oxygen.

[0064] In yet another embodiment of the present invention, Y is NR n1 where R n1 is C 1-8 Alkyl, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-butyl, and tert-butyl; C 1-8O-alkyl, for example, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, iso-butoxy, or tert-butoxy. Such alkyl and alkoxy groups may be independently substituted as defined above. In some cases, R n1 and R 1 may be taken together to form either a heterocyclyl or heteroaryl ring. In a further embodiment, Z is NR n2 where R n2 is C 1-8 Alkyl, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-butyl, and tert-butyl; C 1-8 O-alkyl, for example, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, iso-butoxy, or tert-butoxy. Such alkyl and alkoxy groups may be independently substituted as defined above. In some cases, R n2 and R 3 may be taken together to form either a heterocyclyl ring or a heteroaryl ring.

[0065] In some cases, Y is NR n1 and Z may be NR n2 where R n1 is C 1-8 alkyl, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and tert-butyl; R n2 is C 1-8 alkyl, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and tert-butyl; R 2 is hydrogen or methyl.

[0066] In a further embodiment, the calcium complex has the formula: [ka] In the formula, R1 and R 3 is as defined above, and R 6a and R 6d is hydrogen or C 1-8 alkyl; R 6b and R 6c are, respectively, [ka] where R 7a , R 7b , R 7c , and R 7d is hydrogen, hydroxyl, C 1-8 Alkyl and OC 1-8 alkyl; 7a , R 7b , R 7c , and R 7d wherein any two or more of the groups may be taken together to form a ring.

[0067] In certain embodiments, the calcium chelate complex has the formula: [ka] In the formula, R 5a , R 5b , R 5c , and R 5d is hydrogen; hydroxy; C 1-22 Alkyl, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl; C 1-22 O-alkyl, for example, independently selected from methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, iso-butoxy, or tert-butoxy; 2 , R 5a , R 5b , R 5c , and R 5dmay include compounds having the formula wherein any two or more of may be taken together to form a ring.

[0068] In some cases, the calcium cyclic chelate complex can be one of the following compounds: [ka]

[0069] In some embodiments, the calcium cyclic chelate complex comprises a calcium compound and a cyclic chelate complex of the formula: [ka] During the ceremony Y is O, S, NR n1 is selected from Z is O, S, NR n2 is selected from R 1 , R 2 , R 3 , R n1 , and R n2 is R a , OR b , and N(R b )2 are independently selected from where R a In each case, hydrogen, C 1-8 Alkyl, C 2-8 Alkenyl, C 2-8 Alkynyl, aryl, C 1-8 Heteroaryl, C 3-8 Cycloalkyl, or C 1-8 heterocyclyl; R b In each case, C 1-8 Alkyl, C 2-8 Alkenyl, C 2-8 Alkynyl, aryl, C 1-8 Heteroaryl, C 3-8 Cycloalkyl, or C 1-8 heterocyclyl; where R 1 , R2 , R 3 , R n1 , and R n2 two or more of which may be joined together to form a ring; It may be a reaction product with at least one ligand compound having the formula:

[0070] Suitable calcium compounds include calcium hydroxide and calcium carbonate, either of which may be mixed with calcium oxide. In other cases, the calcium compound may be a salt such as calcium chloride or calcium acetate. In such cases, a salt, such as lithium hydroxide, lithium carbonate, sodium hydroxide, or sodium carbonate, is used to facilitate the reaction between the calcium compound and the ligand. The stoichiometric ratio of calcium compound to ligand compound may be about 1:1, although in some embodiments, either the calcium or the compound may be in excess. In other cases, the calcium compound to ligand ratio may be about 1:2, or 1:3.

[0071] In some cases, the calcium cyclic chelate complex is formed by combining a calcium compound, e.g., a calcium base, with a compound of the formula: [ka] It may be a reaction product with a ligand compound having the formula:

[0072] Suitable calcium compound:ligand moiety ratios include 1:1, 1:2, and 1:3. In some embodiments, R 1 and R 3 are respectively, C 1-8 is an alkyl group, and R 2 is hydrogen. 1-8 Alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-butyl, and tert-butyl. 1-8Alkyl groups may be independently substituted one or more times. Suitable substituents include, but are not limited to, alkoxy, alkenyl, alkynyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, aldehyde, amino, carboxylic acid, ester, ether, halide, hydroxy, ketone, nitro, silyl, sulfo-oxo, phosphine, or thiol.

[0073] In some embodiments of the present invention, R 1 is O.C. 1-8 alkyl, for example, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, iso-butoxy, or tert-butoxy; R 3 is C 1-8 Alkyl, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and tert-butyl. 1-8 The alkyl group is, as shown above, C 1-8 In some cases, R 2 is C 1-8 alkyl, and R 1 and R 3 The following table provides exemplary combinations of R groups that may be present on the ligand: [Table 2-1] [Table 2-2] [Table 2-3]

[0074] In some cases, the calcium cyclic chelate complex is formed by combining a calcium compound, e.g., a calcium base, with a compound of the formula: [ka] In the formula, R2a , R 2b , R 2c , and R 2d is hydrogen; hydroxy; C 1-22 Alkyl, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl; OC 1-22 alkyl, e.g., methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, iso-butoxy, or tert-butoxy; where R 1 , R 2a , R 2b , R 2c , and R 2d may be the reaction product of an ortho-ketophenol having the formula, wherein any two or more of R 2a , R 2b , R 2c , and R 2d may be hydrogen, while in the other, R 2a In some cases, the orthoketophenol may be R 1 is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and tert-butyl, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, or tert-butoxy. In certain preferred embodiments, Y and Z are each oxygen, however the term ortho-ketophenol also refers to, for example, phenols where Y is NR n1 In some cases, the ortho-ketophenol may contain a trisubstituted phenyl ring: [ka] In the formula, R k are hydroxyl, amino, C 1-22Alkyl, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-butyl, and tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl; and OC 1-22 Alkyl, for example, selected from methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, iso-butoxy, or tert-butoxy.

[0075] In some embodiments, the calcium chelate is a calcium chelate comprising a calcium compound, e.g., a calcium base, and a compound of the formula: [ka] where n is 0, 1 or 2; R 4a , R 4a’ , R 4b , R 4b’ , R 4c , R 4c’ , R 4d , R 4d’ , R 4e , and R 4e’ is hydrogen; hydroxy; C 1-22 Alkyl, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl; C 1-22 O-alkyl, for example, independently selected from methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, iso-butoxy, or tert-butoxy; 4a , R 4a’ , R 4b , R 4b’ , R 4c , R 4c’ , R 4d , R 4d’ , R 4e , and R 4e’ may be the reaction product of a ligand compound having the formula, wherein any two or more of R 4c and R 4c’may each be either hydroxyl or amino, and in further embodiments, R 4b and R 4b’ are each methoxy. In certain preferred embodiments, Y and Z are each oxygen.

[0076] In a further embodiment, the calcium chelate is a calcium chelate comprising a calcium compound, e.g., a calcium base, and a calcium chelate of the formula: [ka] In the formula, R 1 and R 3 is as defined above, and R 6a and R 6d is hydrogen or C 1-8 alkyl; R 6b and R 6c are, respectively, [ka] where R 7a , R 7b , R 7c , and R 7d is hydrogen, hydroxyl, C 1-8 Alkyl and OC 1-8 alkyl; 7a , R 7b , R 7c , and R 7d may be a reaction product with a salen compound having the formula, wherein any two or more of the following may be taken together to form a ring.

[0077] In other embodiments, the calcium chelate complex is a calcium chelate complex formed by combining a calcium compound, e.g., a calcium base, with a compound of the formula: [ka] In the formula, R 5a , R 5b , R 5c , and R5d is hydrogen; hydroxy; C 1-22 Alkyl, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl; C 1-22 O-alkyl, for example, independently selected from methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, iso-butoxy, or tert-butoxy; 2 , R 5a , R 5b , R 5c , and R 5d Any two or more of which may be taken together to form a ring with a ligand compound having the formula:

[0078] In further embodiments, the calcium chelate may be the reaction product of a calcium compound, such as a calcium base, with any one of the following ligand compounds: [ka]

[0079] Generally, the amount of calcium cyclic chelate complex 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.

[0080] In one aspect, the present disclosure provides a lubricating oil composition for a direct-injection, boosted, spark-ignition internal combustion engine, comprising at least one calcium chelate complex. In one embodiment, the amount of metal from the at least one calcium cyclic chelate complex is about 100 to about 3,000 ppm, about 200 to about 3,000 ppm, about 250 to about 2,500 ppm, about 300 to about 2,500 ppm, about 350 to about 2,500 ppm, about 400 to about 2,500 ppm, about 500 to about 2,500 ppm, about 600 to about 2,500 ppm, about 700 to about 2,500 ppm, about 700 to about 2,000 ppm, or about 700 to about 1,500 ppm. In one embodiment, the amount of metal from the calcium cyclic chelate complex is about 2,000 ppm or less, or about 1,500 ppm or less.

[0081] In one embodiment, the lubricating composition may include conventional lubricating oil detergent additives containing magnesium and / or calcium. In one embodiment, the calcium detergent(s) may be added in an amount sufficient to provide the lubricating oil composition with from 0 to about 2400 ppm of calcium detergent(s), from 0 to about 2200 ppm of calcium detergent(s), from 100 to about 2000 ppm of calcium detergent(s), from 200 to about 1800 ppm of calcium detergent(s), 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 of calcium detergent(s). In one embodiment, the magnesium detergent(s) may be added in an amount sufficient to provide the lubricating oil composition with 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.

[0082] In one embodiment, the lubricating composition may include a conventional lubricating oil detergent additive containing lithium. In one embodiment, the lithium detergent(s) may be added in an amount sufficient to provide the lubricating oil composition with 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.

[0083] In one embodiment, the lubricating composition may include a conventional lubricating oil detergent additive containing sodium. In one embodiment, the sodium detergent(s) may be added in an amount sufficient to provide the lubricating oil composition with 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.

[0084] In one embodiment, the lubricating composition may include a conventional lubricating oil detergent additive containing potassium. In one embodiment, the potassium detergent(s) may be added in an amount sufficient to provide the lubricating oil composition with 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.

[0085] In one embodiment, a lubricating engine oil composition comprising a lubricating oil base stock as a major component and at least one calcium cyclic chelate complex may be added to an engine. In some embodiments, the engine exhibits a greater than 50% reduction in low speed pre-ignition based on a normalized low speed pre-ignition (LSPI) number per 100,000 engine cycles, engine operation between 500 and 3,000 revolutions per minute, and a brake mean effective pressure (BMEP) between 10 and 30 bar, compared to the low speed pre-ignition performance achieved in an engine using a lubricating oil that does not contain the at least one calcium cyclic chelate complex.

[0086] In one aspect, the present disclosure provides a lubricating engine oil composition for use in a small boosted engine, comprising a lubricating oil base stock as a major component and at least one calcium cyclic chelate complex as a minor component, wherein the small engine has a capacity ranging from 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 2, 3, 4, 5, or 6 cylinders.

[0087] In one aspect, the present disclosure provides the use of at least one calcium cyclic chelate complex to prevent or reduce low speed pre-ignition in a direct injection boosted spark ignition internal combustion engine.

[0088] lubricating oil additives In addition to the calcium cyclic chelate complexes described herein, the lubricating oil composition may contain additional lubricating oil additives.

[0089] The lubricating oil compositions of the present disclosure may also contain other conventional additives, which can impart or improve any desirable properties to the lubricating oil composition in which they are dispersed or dissolved. Any additive known to those skilled in the art may 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 may be blended with antioxidants, antiwear agents, metal detergents, rust inhibitors, dehazing agents, demulsifiers, metal deactivators, friction modifiers, pour point depressants, antifoam agents, cosolvents, 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, and these additives, or similar compounds thereof, are used in preparing the lubricating oil compositions of this disclosure by conventional blending procedures.

[0090] The lubricating oil compositions 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 metal, in which case they are commonly described as normal or neutral salts. Large amounts of metal bases may be incorporated by reacting excess metal compounds (e.g., oxides or hydroxides) with acid gases (e.g., carbon dioxide).

[0091] Detergents that can 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, and mixtures of calcium and / or magnesium with sodium, both of which can be present in detergents used in lubricants.

[0092] The lubricating oil composition of the present invention may contain one or more antiwear agents that can reduce 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 (e.g., Pb, Sb, Mo, etc.) salts of dithiophosphates, 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, phosphites, amine salts of phosphoric acid 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.

[0093] 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 can 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.

[0094] The amount of dihydrocarbyl dithiophosphate metal salt, including zinc dialkyldithiophosphate 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.

[0095] The lubricating oil composition of the present invention may contain one or more friction modifiers capable of reducing 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, borated 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- or di-alkyl-substituted amides, and combinations thereof. In some embodiments, examples of friction modifiers include, but are not limited to, alkoxylated fatty amines; borated fatty epoxides; fatty phosphites, fatty epoxides, fatty amines, borated alkoxylated fatty amines, metal salts of fatty acids, fatty acid amides, glycerol esters, borated glycerol esters; and fatty imidazolines as disclosed in U.S. Pat. No. 6,372,696, the contents of which are incorporated herein by reference; C4-C 75 , or C6~C 24 , or C6~C 20 Friction modifiers derived from the reaction product of a fatty acid ester with a nitrogen-containing compound selected from the group consisting of ammonia and alkanolamines, and mixtures thereof, are included. The amount of friction modifier can vary from about 0.01% to about 10%, from about 0.05% to about 5%, or from about 0.1% to about 3% by weight based on the total weight of the lubricating oil composition.

[0096] The lubricating oil compositions of the present disclosure may contain a molybdenum-containing friction modifier, which may be any one of the known molybdenum-containing friction modifiers or known molybdenum-containing friction modifier compositions.

[0097] Preferred molybdenum-containing friction modifiers include, for example, sulfurized oxymolybdenum dithiocarbamate, sulfurized oxymolybdenum dithiophosphate, amine-molybdenum complex compounds, oxymolybdenum diethylate amide, and oxymolybdenum monoglyceride.Molybdenum dithiocarbamate friction modifiers are most preferred.

[0098] The lubricating oil compositions of the present invention generally contain a molybdenum-containing friction modifier in an amount of 0.01 to 0.15 wt. % molybdenum content.

[0099] The lubricating oil composition of the present invention preferably contains an organic oxidation inhibitor in an amount of 0.01 to 5 wt. %, preferably 0.1 to 3 wt. %. The oxidation inhibitor may be a hindered phenol oxidation inhibitor or a diarylamine oxidation inhibitor. Diarylamine oxidation inhibitors are advantageous in that they provide a base number attributed to the nitrogen atom. Hindered phenol oxidation inhibitors are advantageous in that they do not produce NOx gases.

[0100] Examples of hindered phenol oxidation inhibitors 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, and 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).

[0101] Examples of diarylamine oxidation inhibitors include alkyldiphenylamines having a mixture of alkyl groups of 3 to 9 carbon atoms, p,p-dioctyldiphenylamine, phenyl-naphthylamine, phenyl-naphthylamine, alkylated-naphthylamine, and alkylated phenyl-naphthylamine. The diarylamine oxidation inhibitors may have 1 to 3 alkyl groups.

[0102] The hindered phenol oxidation inhibitors and diarylamine oxidation inhibitors may each be used alone or in combination. If desired, other oil-soluble oxidation inhibitors may be used in combination with the above oxidation inhibitor(s).

[0103] The lubricating oil compositions of the present invention may further contain oxymolybdenum complexes of succinimides, particularly sulfur-containing oxymolybdenum complexes of succinimides, which can provide increased oxidation inhibition when used in combination with the above-mentioned phenolic or amine-based oxidation inhibitors.

[0104] In preparing lubricating oil formulations, it is common practice to introduce the additives in the form of a 10 to 80 wt. % active ingredient concentrate in a hydrocarbon oil, e.g., mineral lubricating oil, or other suitable solvent.

[0105] Typically, these concentrates can 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 a finished lubricant, e.g., crankcase motor oil. The purpose of the concentrate, of course, is to make handling of the various materials less difficult and messy, and to facilitate dissolution or dispersion in the final blend.

[0106] Process for preparing lubricating oil compositions The lubricating oil compositions disclosed herein may be prepared by any method known to those skilled in the art for making lubricating oils. In some embodiments, the base oil may be blended or mixed with the calcium cyclic chelate complex. Optionally, one or more other additives may be added in addition to the calcium cyclic chelate complex. The calcium cyclic chelate complex and optional additives may be added to the base oil individually or simultaneously. In some embodiments, the calcium cyclic chelate complex and optional additives are added to the base oil individually in one or more additions, and such additions may be in any order. In other embodiments, the calcium cyclic chelate complex and additives, optionally in the form of an additive concentrate, are added to the base oil simultaneously. In some embodiments, solubilization of the calcium cyclic chelate complex or any solid additives in the base oil may be aided by heating the mixture to a temperature of from about 25°C to about 200°C, from about 50°C to about 150°C, or from about 75°C to about 125°C.

[0107] Any mixing or dispersing equipment known to those skilled in the art may be used to blend, mix, or solubilize the ingredients. Blending, mixing, or solubilization may be carried out using a blender, agitator, disperser, mixer (e.g., planetary mixers and double planetary mixers), homogenizer (e.g., Gaulin homogenizer and Rannie homogenizer), mill (e.g., colloid mill, ball mill, and sand mill), or any other mixing or dispersing equipment known in the art.

[0108] Uses 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 prone to low-speed pre-ignition, particularly direct-injection boosted engines.

[0109] The following examples are presented to illustrate embodiments of the present invention, but 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. When numerical ranges are given, it should be understood that embodiments outside the stated ranges may still fall within the scope of the invention. The specific details described in each example should not be construed as necessary features of the invention. [Example]

[0110] The following examples are intended to be illustrative of the present invention only and are not intended to limit the scope of the present invention in any way.

[0111] Test compounds were blended into lubricating oils and their capacity to reduce LSPI events was determined using the test method described below.

[0112] Low-speed pre-ignition events were measured in a Ford 2.0L Ecoboost engine. The engine is a turbocharged gasoline direct injection (GDI) engine. The Ford Ecoboost engine is operated in four replicates of approximately four hours. The engine is operated at 1750 rpm and 1.7 MPa brake mean effective pressure (BMEP) with an oil sump temperature of 95°C. The engine is run for 175,000 combustion cycles at each stage, and LSPI events are counted.

[0113] LSPI events are determined by monitoring the peak cylinder pressure (PP) and mass fraction of fuel burned (MFB) in the cylinder. An LSPI event can be said to have occurred when either or both criteria are met. The peak cylinder pressure threshold varies by test but is typically 4-5 standard deviations above the mean cylinder pressure. Similarly, the MFB threshold is typically 4-5 standard deviations earlier than the mean MFB (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 shown below.

[0114] Additives associated with the test lubricants that reduce the frequency of LSPI compared to the corresponding baseline lubricant are considered to be LSPI mitigating additives. The test results are listed in Table 1.

[0115] 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 741-814 ppm phosphorus, a mixture of polyisobutenyl succinimide dispersants (borated and ethylene carbonate post-treated), a molybdenum succinimide complex, an alkylated diphenylamine antioxidant, a borated friction modifier, an antifoam agent, a pour point depressant, and an olefin copolymer viscosity index improver.

[0116] The lubricating oil compositions were blended into a 5W-30 viscosity grade oil.

[0117] (Calcium 2,2,6,6-tetramethyl-3,5-dioxoheptan-4-ide) Calcium 2,2,6,6-tetramethyl-3,5-dioxoheptan-4-ide) was a commercially available product from Millipore Sigma®.

[0118] Example 1 A lubricating oil composition was prepared by adding about 1120 ppm of calcium from calcium 2,2,6,6-tetramethyl-3,5-dioxoheptan-4-ide and about 1120 ppm of calcium from a combination of overbased Ca sulfonate and phenate detergents to a baseline formulation.

[0119] Comparative Example 1 A lubricating oil composition was prepared by adding 2255 ppm of calcium from a combination of overbased Ca sulfonate and phenate detergent to the baseline formulation.

[0120] Comparative Example 2 Lubricating oil compositions were prepared by adding approximately 1000 ppm of calcium from a combination of overbased Ca sulfonate and phenate detergent to a baseline formulation.

[0121] Comparative Example 3 Lubricating oil compositions were prepared by adding about 1120 ppm of calcium from a calcium oleate combination of overbased Ca sulfonate and phenate detergent to the baseline formulation.

[0122] [Table 3] [Table 4]

[0123] The data show that Applicant's inventive examples comprising calcium chelate complexes of the present disclosure, e.g., calcium chelates of 1,3-dicarbonyl compounds, 1,3-ketophenols, 1,3-diimines, or phenols, provided significantly better LSPI performance in a Ford engine, both in terms of number of events and even severe LSPI events, than comparative examples that did not contain calcium cyclic chelate complexes, e.g., calcium chelates of 1,3-dicarbonyl compounds, ortho-ketophenols, 1,3-diimines, mixed chelates, or combinations thereof. Severity is reduced by reducing the number of high-pressure events (i.e., above 120 bar) that can damage the engine.

[0124] Even more impressive about the results obtained with Example 1 was that this calcium compound improved LSPI performance when calcium has been shown to be highly detrimental to LSPI.

[0125] Ball Rust Test (BRT) - ASTM D6557 The BRT is a bench-screening tool for evaluating the rust-inhibitory ability of fluid lubricants. This method is suitable for evaluating automotive engine oils under low-temperature, acidic service conditions. Multiple test tubes, each containing a test oil and a sample—carbon steel balls, 5.6 mm (AISI 1040)—are placed in a test-tube rack attached to a mechanical shaker. The shaker speed is set at 300 rpm, and the temperature is controlled at 48±0.1°C. Air and an acidic solution are continuously supplied to each test tube for an 18-hour period to create a corrosive environment. The carbon steel balls are then removed, rinsed, and analyzed by an optical imaging system that quantifies the rust-inhibitory ability of each test oil by measuring the shade value of each carbon steel ball compared to a calibration standard carbon steel ball. A copy of this test method may be obtained from ASTM International at 100 Barr Harbor Drive, PO Box 0700, West Conshohocken, Pa. 19428-2959, and is incorporated herein for all purposes. [Table 5]

[0126] The basicity of a lubricating oil composition can be determined by acid titration. The resulting neutralization number is expressed as total base number, or TBN, and can be measured using a variety of methods. Two conventional methods of choice are ASTM D4739 (potentiometric hydrochloric acid titration) and ASTM D2896 (potentiometric perchloric acid titration). ASTM D2896 uses stronger acids and a more polar solvent system than ASTM D4739. The combination of stronger acids and more polar solvents results in a more repeatable method for measuring the presence of both strong and weak bases. TBN values ​​determined by ASTM D2896 are often used in new oil specifications. The ASTM D4739 method is favored for engine testing, measuring TBN loss / retention with used oil. Generally, the ASTM D4739 method results in lower TBN measurements because only stronger base species are titrated. A copy of this test method may be obtained from ASTM International, 100 Barr Harbor Drive, PO Box 0700, West Conshohocken, Pa. 19428-2959, and is incorporated herein for all purposes.

[0127] The engine oil composition has excellent performance in the ASTM D6557 Ball Rust Test (BRT). Preferably, the average tint value is at least 100, or at least 110, or at least 120. The calcium compound of Example 1 also provides more TBN to the lubricating oil than conventional detergents.

[0128] The compositions and methods of the appended claims are not limited in scope by the specific compositions and methods described herein, which are intended as illustrations of some aspects of the claims; any compositions and methods that are functionally equivalent are intended to be within the scope of the claims. Various modifications of the compositions and methods in addition to those shown and described herein are intended to be within the scope of the appended claims. Furthermore, while certain representative compositions and method steps disclosed herein have been specifically described, other combinations of compositions and method steps are also intended to be within the scope of the appended claims, even if not specifically recited. Thus, although a combination of steps, elements, components, or components may be explicitly referred to herein or below, other combinations of steps, elements, components, and components are included even if not explicitly recited. The term "comprising" and variations thereof, as used herein, are used synonymously with the term "including" and variations thereof, and are open, non-limiting terms. Although the terms "comprising" and "including" are used herein to describe various embodiments, the terms "consisting essentially of" and "consisting of" may be used in place of "comprising" and "including" to provide more specific embodiments of the present invention, and such terms are also disclosed. Other than as examples, or where otherwise stated, all numbers expressing quantities of ingredients, reaction conditions, and the like used in the specification and claims are not intended to limit the application of the doctrine of equivalents to the claims, but should be construed as a minimum and interpreted in light of the number of significant digits and ordinary rounding approaches.

Claims

1. A lubricating composition comprising a base oil and at least one cyclic calcium chelate complex.

2. 10. The lubricating composition of the preceding claim, wherein the calcium chelate complex comprises a ligand comprising at least one 1,3-dicarbonyl compound, 1,3-ketophenol, 1,3-diimine, or ortho-ketophenol.

3. The calcium chelate complex has the formula: 【Chemistry 1】 During the ceremony: 【Chemistry 2】 independently represent a single or double bond, provided that valence is satisfied; Y is O, S, or NR ｎ１ are independently selected from Z is O, S, or NR ｎ２ are independently selected from R １ , R ２ , R ３ , R ｎ１ , and R ｎ２ is R ａ , OR ｂ , and N(R ｂ ) ２ are independently selected from R ａ is in each case hydrogen, C １－８ Alkyl, C ２－８ Alkenyl, C ２－８ Alkynyl, aryl, C １－８ Heteroaryl, C ３－８ cycloalkyl, or C １－８ heterocyclyl; R ｂ In each case, C １－８ Alkyl, C ２－８ Alkenyl, C ２－８ Alkynyl, aryl, C １－８ Heteroaryl, C ３－８ cycloalkyl, or C １－８ heterocyclyl; R １ , R ２ , R ３ , R ｎ１ , and R ｎ２ two or more of may be joined together to form a ring; 10. A lubricating composition according to any preceding claim, comprising a complex having the formula:

4. The calcium chelate complex has the formula: 【Transformation 3】 10. The lubricating composition of any preceding claim, having

5. R １ is selected from methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, iso-butoxy, tert-butoxy, methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-butyl, and tert-butyl.

6. R ３ is selected from methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, iso-butoxy, tert-butoxy, methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-butyl, and tert-butyl.

7. R ２ is selected from hydrogen, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, iso-butoxy, tert-butoxy, methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-butyl, and tert-butyl.

8. R １ and R ２ 10. A lubricating composition according to any preceding claim, wherein:

9. R ２ and R ３ 10. A lubricating composition according to any preceding claim, wherein:

10. R １ , R ２ and R ３ 10. A lubricating composition according to any preceding claim, wherein:

11. The calcium chelate complex comprises: 【Chemistry 4】 During the ceremony, R ２ａ , R ２ｂ , R ２ｃ , and R ２ｄ is hydrogen; hydroxy; C １－２２ alkyl; and O—C １－２２ independently selected from alkyl, R １ , R ２ａ , R ２ｂ , R ２ｃ , and R ２ｄ any two or more of may be taken together to form a ring; 10. A lubricating composition according to any preceding claim, comprising the formula:

12. The calcium chelate complex comprises: 【Transformation 5】 During the ceremony, R ｋ is hydroxyl, amino, C １－２２ Alkyl, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-butyl, and tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl; and O—C １－２２ alkyl, for example selected from methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, iso-butoxy, or tert-butoxy; 10. A lubricating composition according to any preceding claim, comprising the formula:

13. The calcium chelate complex has the formula: 【Transformation 6】 n is 0, 1 or 2; R ４ａ , R ４ａ’ , R ４ｂ , R ４ｂ’ , R ４ｃ , R ４ｃ’ , R ４ｄ , R ４ｄ’ , R ４ｅ , and R ４ｅ’ is hydrogen; hydroxy; C １－２２ Alkyl, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-butyl, and tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl; C １－２２ O-alkyl, for example, independently selected from methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, iso-butoxy, or tert-butoxy; R ４ａ , R ４ａ’ , R ４ｂ , R ４ｂ’ , R ４ｃ , R ４ｃ’ , R ４ｄ , R ４ｄ’ , R ４ｅ , and R ４ｅ’ Any two or more of may be joined together to form a ring, and preferably R ４ｃ and R ４ｃ’ is either hydroxyl or amino, preferably R ４ｂ and R ４ｂ’ are methoxy, 10. A lubricating composition according to any preceding claim, having the formula:

14. Y is NR ｎ１ and R ｎ１ is C １－８ Alkyl, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-butyl, and tert-butyl; C １－８ 10. The lubricating composition of any preceding claim, wherein O-alkyl is, for example, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, iso-butoxy, or tert-butoxy.

15. Z is NR ｎ２ and R ｎ２ is C １－８ Alkyl, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-butyl, and tert-butyl; C １－８ 10. The lubricating composition of any preceding claim, wherein O-alkyl is, for example, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, iso-butoxy, or tert-butoxy.

16. Y is NR ｎ１ and Z is NR ｎ２ and R ｎ１ is C １－８ alkyl, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-butyl, and tert-butyl; R ｎ２ is C １－８ alkyl, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-butyl, and tert-butyl; R ２ 4. The lubricating composition of any preceding claim, wherein is hydrogen or methyl.

17. The calcium complex has the formula: 【Transformation 7】 During the ceremony, R ６ａ and R ６ｄ is hydrogen or C １－８ alkyl; R ６ｂ and R ６ｃ are, respectively, 【Transformation 8】 and R ７ａ , R ７ｂ , R ７ｃ , and R ７ｄ is hydrogen, hydroxyl, C １－８ Alkyl, and O-C １－８ independently selected from alkyl, R ７ａ , R ７ｂ , R ７ｃ , and R ７ｄ any two or more of may be taken together to form a ring; 10. A lubricating composition according to any preceding claim, having the formula:

18. The calcium chelate complex has the formula: 【Chemistry 9】 During the ceremony, R ５ａ , R ５ｂ , R ５ｃ , and R ５ｄ is hydrogen; hydroxy; C １－２２ Alkyl, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-butyl, and tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl; C １－２２ O-alkyl, for example, independently selected from methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, iso-butoxy, or tert-butoxy; R ２ , R ５ａ , R ５ｂ , R ５ｃ , and R ５ｄ any two or more of may be taken together to form a ring; 10. A lubricating composition according to any preceding claim, having the formula:

19. The cyclic calcium chelate complex is formed by mixing a calcium compound with a compound of the formula: 【Chemistry 10】 During the ceremony Y is O, S, NR ｎ１ is selected from Z is O, S, NR ｎ２ is selected from R １ , R ２ , R ３ , R ｎ１ , and R ｎ２ is R ａ , OR ｂ , and N(R ｂ ) ２ are independently selected from R ａ is in each case hydrogen, C １－８ Alkyl, C ２－８ Alkenyl, C ２－８ Alkynyl, aryl, C １－８ Heteroaryl, C ３－８ cycloalkyl, or C １－８ heterocyclyl; R ｂ In each case, C １－８ Alkyl, C ２－８ Alkenyl, C ２－８ Alkynyl, aryl, C １－８ Heteroaryl, C ３－８ cycloalkyl, or C １－８ heterocyclyl; R ２ａ , R ２ｂ , R ２ｃ , and R ２ｄ is hydrogen; hydroxy; C １－２２ alkyl; and O—C １－２２ independently selected from alkyl, Any two or more R groups may be joined together to form a ring; 10. A lubricating composition according to any preceding claim which is a reaction product with a ligand having the formula:

20. The calcium chelate complex comprises a calcium compound and a compound of the formula: 【Chemistry 11】 During the ceremony, n is 0, 1 or 2; R ４ａ , R ４ａ’ , R ４ｂ , R ４ｂ’ , R ４ｃ , R ４ｃ’ , R ４ｄ , R ４ｄ’ , R ４ｅ , and R ４ｅ’ is hydrogen; hydroxy; C １－２２ Alkyl, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-butyl, and tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl; C １－２２ O-alkyl, for example, independently selected from methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, iso-butoxy, or tert-butoxy; R ４ａ , R ４ａ’ , R ４ｂ , R ４ｂ’ , R ４ｃ , R ４ｃ’ , R ４ｄ , R ４ｄ’ , R ４ｅ , and R ４ｅ’ Any two or more of may be joined together to form a ring, and preferably R ４ｃ and R ４ｃ’ is either hydroxyl or amino, preferably R ４ｂ and R ４ｂ’ are each methoxy, 10. A lubricating composition according to any preceding claim which is a reaction product with a ligand compound having the formula:

21. The calcium chelate complex comprises a calcium compound and a compound of the formula: 【Chemistry 12】 During the ceremony, R ｋ is hydroxyl, amino, C １－２２ Alkyl, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-butyl, and tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl; and O—C １－２２ alkyl, for example selected from methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, iso-butoxy, or tert-butoxy; 10. A lubricating composition according to any preceding claim which is a reaction product with a ligand compound having the formula:

22. The calcium chelate complex comprises a calcium compound and a compound of the formula: 【Chemistry 13】 During the ceremony, R ５ａ , R ５ｂ , R ５ｃ , and R ５ｄ is hydrogen; hydroxy; C １－２２ Alkyl, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-butyl, and tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl; C １－２２ O-alkyl, for example, independently selected from methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, iso-butoxy, or tert-butoxy; R ２ , R ５ａ , R ５ｂ , R ５ｃ , and R ５ｄ any two or more of may be taken together to form a ring; 10. A lubricating composition according to any preceding claim which is a reaction product with a ligand compound having the formula:

23. The calcium chelate complex comprises a calcium compound and a compound of the formula: 【Chemistry 14】 During the ceremony, R ６ａ and R ６ｄ is hydrogen or C １－８ alkyl; R ６ｂ and R ６ｃ are, respectively, 【Chemistry 15】 and R ７ａ , R ７ｂ , R ７ｃ , and R ７ｄ is hydrogen, hydroxyl, C １－８ Alkyl, and O-C １－８ independently selected from alkyl, R ７ａ , R ７ｂ , R ７ｃ , and R ７ｄ any two or more of may be taken together to form a ring; 10. A lubricating composition according to any preceding claim which is a reaction product with a ligand compound having the formula:

24. 10. The lubricating composition of any preceding claim, wherein the calcium compound comprises a calcium base.

25. 10. The lubricating composition of any preceding claim, wherein the calcium compound comprises a calcium salt.

26. 26. A method of preventing or reducing low speed pre-ignition events in an internal combustion engine having a crankcase, the method comprising contacting the crankcase with a lubricating composition according to any one of claims 1 to 25.

27. 27. The method of claim 26, wherein the low speed pre-ignition events experienced by the internal combustion engine are 90% or less, 80% or less, 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, or 5% or less of the low speed pre-ignition events experienced by an internal combustion engine lubricated with an otherwise similar lubricating composition that does not contain the calcium cyclic chelate complex.

28. A method of reducing or preventing corrosion in an internal combustion engine having a crankcase, the method comprising contacting the crankcase with a lubricating composition according to any one of claims 1 to 25.

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