Lubricating fluid for internal combustion engines that operate on alternative combustion fuels with high spontaneous ignition temperatures.

Abstract

The present invention provides a lubricating oil composition, a lubrication method, and an internal combustion engine configured for the combustion of hydrogen fuel, which is configured for lubricating an internal combustion engine that operates on an alternative fuel having an ignition temperature of over approximately 700K. [Solution] The lubricating oil composition comprises at least one detergent system including at least one overbasic metal-containing sulfonate detergent, at least one neutral to low-basic metal-containing sulfonate detergent, and at least one overbasic metal-containing phenate detergent, wherein the metal provided by the overbasic sulfonate detergent is precisely balanced with respect to the total detergent metals and / or the total base number of the composition.

Description

Technical Field

[0001] The present disclosure relates to a lubricating fluid for an internal combustion engine operating on an alternative combustion fuel having a high autoignition temperature, and a method of lubricating an internal combustion engine using the lubricating fluid when operating on such an alternative combustion fuel.

Background Art

[0002] Many engine and vehicle manufacturers are exploring the use of alternative combustion fuels such as those having a high autoignition temperature of about 700 K or more as an alternative to gasoline or diesel fuel. Such alternative fuels include at least hydrogen fuel, compressed natural gas (CNG), and / or liquefied natural gas (LNG). Hydrogen fuel engines or natural gas fuel engines have several advantages. For example, existing internal combustion engines can generally be operated using such fuels with little or no modification, which simplifies implementation due to the ability to utilize a robust and durable engine platform that has a long history and is well understood.

[0003] However, one problem in the context of hydrogen fuel or natural gas fuel engines is a problem called stochastic preignition (SPI), which tends to be a limiting factor when developing for the widespread use of hydrogen fuel or natural gas fuel internal combustion engines. SPI in a hydrogen fuel engine or natural gas fuel engine is an early ignition event of the main fuel charge, resulting in early detonation, misfire, and / or knocking. This is similar to the low-speed preignition (LSPI) often seen in gasoline engines of certain turbocharged direct injection engines. Unfortunately, known solutions for improving LSPI in conventional gasoline fuel engines do not necessarily lead to an improvement in SPI in hydrogen fuel or natural gas fuel engines.

Summary of the Invention

[0004] In one embodiment, a lubricating oil composition configured for lubricating an internal combustion engine powered by a fuel having an ignition temperature greater than approximately 700K is described herein. In this embodiment, the lubricating oil composition is effective in reducing or minimizing stochastic pre-ignition (SPI). The lubricating oil composition comprises one or more base oils of lubricating viscosity and a detergent system comprising: (i) at least one overbasic metal-containing sulfonate detergent that provides about 2 to about 8 mmol of metal to the composition; (ii) at least one neutral to low-basic metal-containing sulfonate detergent that provides at least about 0.02 mmol of metal to the composition; and (iii) at least one overbasic metal-containing phenate detergent that provides up to about 4 mmol of metal to the composition, wherein the lubricating oil composition has a total base number (TBN) of at least about 9.5 as measured in accordance with ASTM D2896.

[0005] In other approaches or embodiments, the lubricating compositions described in the preceding paragraph include any combination of other features or embodiments. These other features or embodiments include one or more of the following: the ratio of the percentage of metal provided from the overbasic metal-containing sulfonate detergent to the TBN (ASTM D2896) of the lubricating oil composition is about 0.07 or less (or about 0.06 or less), and / or the TBN of the lubricating oil composition is about 10 to about 15 when measured in accordance with ASTM D2896, and / or the lubricating oil composition has a sulfated ash (SASH) content of more than 0.9 weight percent when measured in accordance with ASTM D874, and / or the lubricating oil composition is ASTM A cleaning agent system having a sulfated ash (SASH) content of more than 1.2 wt percent when measured in accordance with D874, and / or providing about 1000 to about 5000 ppm of calcium, and / or providing about 10 to about 800 ppm of magnesium, and / or providing only calcium, and / or further comprising one or more oil-soluble molybdenum compounds that provide about 200 ppm or less of molybdenum, and / or comprising at least a perbasic metal-containing sulfonate cleaning agent, at least a perbasic metal-containing phenate cleaning agent, or a combination thereof, wherein each perbasic cleaning agent contains at least about 200 TBN (ASTM The composition has D2896) and / or one or more base oils of lubricating viscosity comprises an API Group I base oil, an API Group II base oil, or a combination thereof, and / or the composition is configured to lubricate an internal combustion engine powered by a fuel having an ignition temperature greater than approximately 800K, and / or the composition is configured to lubricate an internal combustion engine powered by a fuel having an ignition temperature greater than approximately 850K, and / or the lubricating oil composition has an average measured stochastic pre-ignition (SPI) of less than or equal to 6 stochastic pre-ignition (SPI) counts at 1000 rpm and a net mean effective pressure (BMEP) of 12 bar, and / or the fuel having an ignition temperature greater than approximately 700K is hydrogen fuel.

[0006] In further approaches or embodiments, the disclosure also provides a method for lubricating an internal combustion engine when operating with a fuel having an ignition temperature greater than about 700K in order to mitigate abnormal combustion events. In one embodiment, the method comprises lubricating the crankcase of an internal combustion engine with any embodiment of the lubricating oil composition described in the abstract of this invention and burning a fuel having an ignition temperature greater than about 700K in the internal combustion engine. In another embodiment, the lubricating oil composition comprises (i) one or more base oils of lubricating viscosity, and (ii) a detergent system comprising (iia) at least one overbasic metal-containing sulfonate detergent that provides about 2 to about 8 mmol of metal to the composition, (iib) at least one neutral to low-basic metal-containing sulfonate detergent that provides at least about 0.02 mmol of metal to the composition, and (iic) at least one overbasic metal-containing phenate detergent that provides up to about 4 mmol of metal to the composition, wherein the lubricating oil composition has a total base number (TBN) of at least about 9.5 as measured in accordance with ASTM D2896.

[0007] In other embodiments, the method described in the preceding paragraph further includes, in any combination, other features, process steps, or embodiments. These other features, process steps, or embodiments include one or more of the following: the ratio of the percentage of metal provided from the overbasic metal-containing sulfonate detergent to the TBN of the lubricating oil composition (ASTM D2896) is about 0.07 or less (or about 0.06 or less), and / or the TBN of the lubricating oil composition is about 10 to about 15 when measured in accordance with ASTM D2896, and / or the lubricating oil composition has a sulfated ash (SASH) content of more than 0.9 weight percent when measured in accordance with ASTM D874, and / or the lubricating oil composition is ASTM A cleaning agent system having a sulfated ash (SASH) content of more than 1.2 wt percent when measured according to D874, and / or providing about 1000 to about 5000 ppm of calcium, and / or providing about 10 to about 800 ppm of magnesium, and / or providing only calcium metal, and / or further comprising one or more oil-soluble molybdenum compounds that provide about 200 ppm or less of molybdenum, and / or comprising at least an overbasic metal-containing sulfonate cleaning agent, at least an overbasic metal-containing phenate cleaning agent, or a combination thereof, wherein each overbasic cleaning agent contains at least about 200 TBN (ASTM The composition has D2896) and / or one or more base oils of lubricating viscosity comprises an API Group I base oil, an API Group II base oil, or a combination thereof, and / or the composition is configured to lubricate an internal combustion engine powered by a fuel having an ignition temperature greater than approximately 800K, and / or the composition is configured to lubricate an internal combustion engine powered by a fuel having an ignition temperature greater than approximately 850K, and / or the fuel having an ignition temperature greater than approximately 700K is hydrogen fuel, compressed natural gas, or liquefied natural gas, and / or the lubricating oil composition has an average measured stochastic pre-ignition (SPI) of less than or equal to approximately 6 stochastic pre-ignition (SPI) counts at a net mean effective pressure (BMEP) of 1000 rpm and 12 bar.

[0008] In further embodiments or approaches, the Disclosure also describes an internal combustion engine configured for the combustion of hydrogen fuel, the internal combustion engine comprising an engine crankcase lubricated with any embodiment of the lubricating oil composition as described in the Outline of the Invention, and in other embodiments, the lubricating oil composition comprises (i) one or more base oils of lubricating viscosity, and (ii) a detergent system comprising (iia) at least one overbasic metal-containing sulfonate detergent that provides about 2 to about 8 mmol of metal to the composition, (iib) at least one neutral to low-basic metal-containing sulfonate detergent that provides at least about 0.02 mmol of metal to the composition, and (iic) at least one overbasic metal-containing phenate detergent that provides up to about 4 mmol of metal to the composition, wherein the lubricating oil composition has a total base number (TBN) of at least about 9.5 as measured in accordance with ASTM D2896.

[0009] In further embodiments or approaches, the internal combustion engine described in the preceding paragraph may include other features or embodiments in any combination. These other features or embodiments include one or more of the following: the ratio of the percentage of metal provided by the overbasic metal-containing sulfonate detergent to the TBN (ASTM D2896) of the lubricating oil composition is about 0.07 or less (or about 0.06 or less), and / or the TBN of the lubricating oil composition is about 10 to about 15 when measured in accordance with ASTM D2896, and / or the lubricating oil composition has a sulfated ash (SASH) content of more than 0.9 weight percent when measured in accordance with ASTM D874, and / or the lubricating oil composition is ASTM A cleaning agent system having a sulfated ash (SASH) content of more than 1.2 wt percent when measured according to D874, and / or providing about 1000 to about 5000 ppm of calcium, and / or providing about 10 to about 800 ppm of magnesium, and / or providing only calcium metal, and / or further comprising one or more oil-soluble molybdenum compounds that provide about 200 ppm or less of molybdenum, and / or comprising at least an overbasic metal-containing sulfonate cleaning agent, at least an overbasic metal-containing phenate cleaning agent, or a combination thereof, wherein each overbasic cleaning agent contains at least about 200 TBN (ASTM The lubricating oil composition has D2896) and / or one or more base oils of lubricating viscosity, comprising an API Group I base oil, an API Group II base oil, or a combination thereof, and / or has an average measured stochastic pre-ignition (SPI) of about 6 or less at a net mean effective pressure (BMEP) of 1000 rpm and 12 bar.

[0010] In further embodiments, the use of any embodiment of a lubricating oil composition as outlined herein is also provided herein for use in an internal combustion engine powered by a fuel having an ignition temperature greater than approximately 700K, a fuel having an ignition temperature greater than approximately 800K, or a fuel having an ignition temperature greater than approximately 850K, and / or when the fuel having an ignition temperature greater than approximately 700K is hydrogen fuel, compressed natural gas, or liquefied natural gas, to achieve an average measured stochastic pre-ignition (SPI) of less than or equal to approximately 6 stochastic pre-ignition (SPI) counts at 1000 rpm and 12 bar net mean effective pressure (BMEP).

[0011] Other embodiments of the present disclosure will be apparent to those skilled in the art in consideration of the specification of the invention disclosed herein and the practice of the invention. [Brief explanation of the drawing]

[0012] [Figure 1] This is a graph of stochastic preignition (SPI) against the ratio of the percentage of metal from the overbasic sulfonate detergent to the total base number of the lubricant, measured according to ASTM D2896. [Modes for carrying out the invention]

[0013] Stochastic pre-ignition (SPI) is a limiting factor in the widespread use of alternative combustion fuels (fuels with an ignition temperature of at least about 700K, as considered herein) in internal combustion engines. SPI is a phenomenon that tends to be similar to low-speed pre-ignition (LSPI) in gasoline engines, which can be encountered in certain turbocharged direct-injection gasoline engines; however, solutions to address LSPI in gasoline engines do not necessarily improve SPI in, for example, hydrogen fuel or natural gas fuel internal combustion engines. LSPI can be mitigated by optimizing the effects of calcium in engine lubricants, but this solution has little to no effect on improving SPI events in hydrogen fuel or natural gas fuel internal combustion engines. Therefore, conventional gasoline engine oils are not necessarily suitable for use in engines operating on alternative combustion fuels, such as hydrogen fuel or natural gas fuel internal combustion engines.

[0014] According to exemplary embodiments herein, lubricating oil compositions are provided for use in an internal combustion engine fueled by an alternative fuel having an ignition temperature of at least about 700 K (preferably a fuel having an ignition temperature of 850 K or higher, most preferably hydrogen fuel), or for a method of lubricating such an internal combustion engine. The lubricating oil compositions herein are effective in reducing SPI in engines powered by alternative fuels. In one aspect or embodiment, the lubricating composition comprises one or more base oils of lubricating viscosity and a selected detergent system, the selected detergent system comprising: (i) at least one overbasic metal-containing sulfonate detergent that provides a specific amount of metal to the lubricating composition; (ii) optionally at least one low-basic and / or neutral metal-containing sulfonate detergent that provides a certain amount of metal to the composition; and (iii) at least one overbasic metal-containing phenate detergent that provides a certain amount of metal to the composition, wherein the lubricating composition has a total base number (TBN) of at least about 9.5 as measured in accordance with ASTM D2896. As shown in the following examples, the amount of detergent metal from each of these detergent sources, when precisely balanced, helps reduce SPI. In other embodiments or designs, the lubricating compositions herein may also have a selected relationship or ratio of the percentage of overbasic metal from the overbasic sulfonate detergent to the total detergent metal, and further to TBN (ASTM D2896), such a ratio of about 0.07 or less (or about 0.06 or less). As also shown in the following examples, this discovered ratio may also help reduce SPI in some embodiments.

[0015] Higher levels of metal (such as calcium) from overbasic-containing sulfonate detergents tend to adversely affect SPI in the context of hydrogen fuel engines or natural gas fuel engines. However, in one embodiment, a careful balance between the amount of metal from overbasic metal-containing sulfonate detergents, the amount of metal from overbasic metal-containing phenate detergents and / or the amount of metal from low-basic or neutral metal-containing sulfonate detergents, and / or in other embodiments, a careful balance of the percentage relationship between the metal from the overbasic sulfonate detergents and the total detergent metal, and / or further to the TBN (ASTM D2896) of the final fluid, has been found to mitigate SPI in internal combustion engines operating on alternative combustion fuels described herein, having an ignition temperature of at least about 700K. As shown by the examples, the lubricating oil compositions having the detergent system described herein achieve a reduction in mean SPI when the engine is running on an alternative fuel having an ignition temperature of at least about 700K, particularly hydrogen fuel, compressed natural gas fuel, and / or liquefied natural gas fuel, most preferably hydrogen fuel such as gaseous hydrogen fuel.

[0016] Cleansing agents The cleaning agent system of the lubricating oil composition herein comprises one or more metal-containing cleaning agents, preferably one or more overbasic metal-containing sulfonate cleaning agents, optionally one or more overbasic metal-containing phenate cleaning agents, and / or optionally one or more neutral to low-basic to neutral metal-containing sulfonate cleaning agents. In one embodiment, the one or more metal-containing cleaning agents include one or more overbasic sulfonate cleaning agents, one or more overbasic phenate cleaning agents, and one or more neutral to low-basic or neutral sulfonate cleaning agents. In some embodiments, the overbasic cleaning agents herein have a total base number (TBN) of at least about 200 (preferably about 240 to about 450 or about 250 to about 420) as measured by ASTM D2896, and the neutral to low-basic or neutral cleaning agents have a total base number (TBN) of 50 or less as measured by ASTM D2896. Suitable cleaning agents and methods for preparing the same are described in detail in numerous patent publications, including, for example, U.S. Patent No. 7,732,390, No. 4,165,291, and / or No. 4,206,062 (and the references cited herein), which are incorporated herein by reference.

[0017] In the embodiment, a suitable detergent base (e.g., sulfonate or phenate) may be salted with an alkali or alkaline earth metal, where these metals are preferably calcium and / or magnesium, most preferably calcium. In an approach or embodiment, the cleaning agent system herein preferably comprises (i) at least one overbasic metal-containing sulfonate cleaning agent that provides the composition with about 2 to about 8 mmol of metal (preferably about 2.5 to about 7.5 mmol of metal, more preferably the metal is calcium and / or magnesium, most preferably calcium); (ii) at least one neutral to low-basic to neutral metal-containing sulfonate cleaning agent that provides the composition with at least about 0.02 mmol of metal (preferably about 0.025 to about 0.2 mmol of metal, more preferably the metal is calcium and / or magnesium, most preferably calcium); and (iii) at least one overbasic metal-containing phenate cleaning agent that provides the composition with up to about 4 mmol of metal (preferably about 2 to about 3.5 mmol of metal, more preferably the metal is calcium and / or magnesium, most preferably the metal is calcium), and the composition is ASTM It has a total base number (TBN) of at least about 9.5 (preferably about 10 to about 15, most preferably about 10 to about 12) as measured in accordance with D2896. In other embodiments, the cleaning agent system herein provides about 1000 to about 5000 ppm of calcium and / or about 10 to about 800 ppm of magnesium.

[0018] In embodiments, in accordance with the discussion of detergent systems herein, suitable detergents may include petroleum sulfonic acid, and long-chain mono- or dialkylaryl sulfonic acid having an aryl group of benzyl, tolyl, and xylyl, and / or linear or branched alkali metal salts or alkaline earth metal salts of various phenates or derivatives of phenates, such as calcium salts, sodium salts, or magnesium salts. Examples of suitable detergents (in accordance with the limitations of TBN and metals described herein) include, but are not limited to, the following low-basic, neutral, and / or over-basic variations of detergents. Calcium phenate, calcium sulfur-containing phenate, calcium sulfonate, calcium calixalate, calcium salixalate, calcium salicylate, calcium carboxylic acid, calcium phosphate, calcium mono- and / or di-thiophosphate, calcium alkylphenol, calcium sulfur-bonded alkylphenol compound, calcium methylene crosslinked phenol, magnesium phenate, magnesium sulfur-containing phenate, magnesium sulfonate, magnesium calixalate, magnesium salixalate, magnesium salicylate, magnesium carboxylic acid, magnesium phosphate, magnesium mono- and / or di-thiophosphate, magnesium alkylphenol, magnesium sulfur-bonded alkylphenol compound, magnesium methylene crosslinked phenol, sodium phenate, sodium sulfur-containing phenate, sodium sulfonate, sodium calixalate, sodium salixalate, sodium salicylate, sodium carboxylic acid, sodium phosphate, sodium mono- and / or di-thiophosphate, sodium alkylphenol, sodium sulfur-bonded alkylphenol compound, or sodium methylene crosslinked phenol. Preferably, the cleaning agent system of this specification comprises at least a superbasic calcium and / or magnesium sulfonate cleaning agent and a superbasic calcium and / or magnesium phenate cleaning agent, providing the above amount of metal.

[0019] Overbasic metal-containing sulfonate and phenate detergents, as well as optional low-basic to neutral metal-containing sulfonate detergents, are well known in the art and generally include alkaline or alkaline earth metal overbasic detergent additives. Such detergent additives can be prepared by reacting a metal oxide or metal hydroxide with a base and carbon dioxide gas. The base is typically an acid, such as an aliphatic-substituted sulfonic acid or aliphatic-substituted phenol in the context of lubricants herein.

[0020] The term “overbasic” refers to metal salts, such as the metal salts of the fluids herein, in which the amount of metal present exceeds the stoichiometric amount. Such salts may have a conversion level greater than 100% (i.e., such salts may contain more than 100% of the theoretical amount of metal required to convert an acid to its “standard” or “neutral” salt). The expression “metal ratio,” often abbreviated as MR (metal ratio), is used to indicate the ratio of the total stoichiometric equivalents of metal in an overbasic salt to the stoichiometric equivalents of metal in a neutral salt, according to known chemical reactivity and stoichiometry. In standard or neutral salts, the metal ratio is 1, while in overbasic salts, the MR is greater than 1. They are commonly referred to as overbasic, highly basic, or ultrabasic salts and may be salts of organic sulfur acids. When used herein, the overbasic detergents herein may, in one embodiment, have a total base number (TBN) of about 200 mg KOH / gram or more, about 240 mg KOH / gram or more, about 250 mg KOH / gram or more, about 280 mg KOH / gram or more, or about 300 mg KOH / gram or more. When used herein, the total base number or TBN of the detergent additive is determined using ASTM D2896. When such a detergent composition is formed in an inert diluent, e.g., process oil, usually mineral oil, the total base number reflects the basicity of the overall composition, including the diluent and any other materials that may be included in the detergent composition (e.g., accelerators).

[0021] Examples of suitable overbasic detergents (subject to the TBN and metal limitations specified herein) include, but are not limited to, overbasic calcium phenates, overbasic calcium and sulfur-containing phenates, overbasic calcium sulfonates, overbasic calcium calixalates, overbasic calcium salixalates, overbasic calcium salicylates, overbasic calcium carboxylic acids, overbasic calcium phosphates, overbasic calcium mono- and / or di-thiophosphates, overbasic calcium alkylphenols, overbasic calcium sulfur-linked alkylphenol compounds, overbasic calcium methylene crosslinked phenols, overbasic magnesium phenates, overbasic magnesium sulfur-containing phenates, overbasic magnesium sulfonates, overbasic magnesium calixalates, overbasic magnesium salixalates, overbasic magnesium salicylates, overbasic magnesium carboxylic acids, overbasic magnesium phosphates, overbasic magnesium mono- and / or di-thiophosphates, overbasic magnesium alkylphenols, overbasic magnesium sulfur-linked alkylphenol compounds, or overbasic magnesium methylene crosslinked phenols.

[0022] In some embodiments, the detergent systems used in the lubricants herein comprise a superbasic calcium sulfonate, a superbasic magnesium sulfonate, or a combination thereof, each superbasic detergent having a total base number (TBN) (ASTM D2896) of 200 to 450, or in other approaches, about 200 to about 425, or about 250 to about 425, or about 280 to about 425. In other embodiments, the detergent systems herein may also comprise a superbasic calcium phenate, a superbasic magnesium phenate, or a combination thereof, each having a total base number (ASTM D2896) of 200 to 450, or in other approaches, about 200 to about 400, or about 225 to about 350, or about 240 to about 300. In further embodiments, the detergent systems of this specification may also include low-basic to neutral calcium sulfonates, low-basic to neutral magnesium sulfonates, or combinations thereof, each having a total base number (ASTM D2896) of 50 or less, or in other approaches, about 0 to about 50, or about 0 to about 40, or about 0 to about 30. The above TBN values ​​reflect the values ​​of the finished detergent components diluted in the base oil.

[0023] While not wishing to be limited by theory, lubricants having higher levels of overbased sulfonate detergents tend to exhibit higher levels of undesirable SPI events when used to lubricate engines operating on alternative combustion fuels described herein (e.g., fuels having a self-ignition temperature of at least about 700 K (e.g., hydrogen or natural gas fuels)). However, acceptable levels of SPI can be achieved when the metals provided by the overbased sulfonate detergent content are accurately balanced relative to the total detergent metals and / or when the percentage of metals from the overbased sulfonate detergent is balanced relative to the lubricant TBN (ASTM D2896). As shown in FIG. 1 and the examples below, for example, when the ratio of the weight percentage of metals from the overbased sulfonate detergent to the lubricant TBN (ASTM D2896) is about 0.07 or less, in other embodiments, about 0.06 or less, about 0.055 or less, or about 0.01 to about 0.07, about 0.01 to about 0.06, or about 0.02 to about 0.055 (or any other range between the recited endpoints), the average SPI event is less than 6 average SPI events per 1000 cycles, and in other embodiments, 2 to 6 average SPI events per 1000 cycles. As described in the Examples section below, SPI can be evaluated at, for example, FEV Europe GmbH or other suitable test facilities using a 6-cylinder engine modified (as necessary) to operate using an alternative fuel (e.g., a fuel having a self-ignition temperature of at least 700 K such as hydrogen fuel, compressed natural gas fuel, or liquefied natural gas fuel) at 1000 rpm and a net mean effective pressure (BMEP) of 12 bar. As shown in FIG. 1 and the examples, when the percentage of metals provided by the overbased sulfonate detergent (e.g., mmol of metals from the overbased sulfonate detergent divided by the total mmol of metals from the detergent) is too high relative to the TBN of the detergent, the SPI event increases to an undesirable level (generally, an average SPI event of 6 or more).

[0024] Lubricating oil composition The lubricant composition of the present specification includes the above detergent system and other additives suitable for lubricating an internal combustion engine when using an alternative combustion fuel having the described autoignition temperature. In one approach, the total base number of the lubricating composition of the present specification is at least about 9.5 when measured in accordance with ASTM D2896, in other embodiments, from about 10 to about 15, and in further embodiments, from about 10 to about 12. As described above, this TBN is balanced with respect to the percentage of metal provided by the overbased sulfonate detergent and can reduce SPI at a desirable ratio of about 0.07 or less (or other ratios as described herein), as shown in the examples.

[0025] The lubricant composition of the present specification can also provide a higher level of sulfuric acid ash, measured by ASTM D874, in some embodiments. For example, in embodiments, the lubricant composition of the present specification has a sulfuric acid ash (SASH) of greater than about 0.9 weight percent, greater than about 1.0 weight percent, greater than about 1.1 weight percent, greater than about 1.2 weight percent, greater than about 1.3 weight percent, greater than about 1.4 weight percent, or greater than about 1.5 weight percent. In other embodiments, the lubricant composition of the present specification has a sulfuric acid ash (SASH) content of up to about 1.0 weight percent, or up to about 1.6 weight percent, or from about 1.0 weight percent to about 1.6 weight percent, or from about 1.2 weight percent to about 1.6 weight percent when measured by ASTM D874.

[0026] Base oil: The lubricating fluids herein comprise one or more base oils having a lubricating viscosity. Suitable base oils for use in formulating the lubricating oil compositions herein for use in lubricating internal combustion engines powered by alternative fuels as described herein may be selected from suitable synthetic oils or natural oils, or mixtures thereof, having a suitable lubricating viscosity. Natural oils may include animal oils and vegetable oils (e.g., castor oil, lard), as well as liquid petroleum and mineral oils such as paraffinic, naphthenic, or mixed paraffin-naphthenic solvent-treated or acid-treated mineral lubricants. Oils derived from coal or shale may also be suitable. Furthermore, oils derived from gas liquefaction processes are also suitable. The base oils may have a kinematic viscosity at 100°C (e.g., kV100) of about 2 to about 15 cSt, as measured by ASTM D2270-10.

[0027] The base oils used in the present invention as described herein may be a single base oil or a mixture of two or more base oils. In one embodiment, one or more base oils may be selected from any of the base oils in Groups I to IV specified in the American Petroleum Institute (API) Base Oil Interoperability Guidelines. In other embodiments, one or more base oils of lubrication viscosity preferably consist only of API Group I base oils, API Group II base oils, or a combination thereof. Such base oil groups are shown below in Table 1.

[0028] [Table 1]

[0029] API Group III base oils may include oils derived from Fischer-Tropsch synthetic hydrocarbons. Fischer-Tropsch synthetic hydrocarbons are produced from synthesis gas containing H2 and CO using a Fischer-Tropsch catalyst. Such hydrocarbons typically require further processing to be useful as base oils. These types of oils are commonly referred to as gas-liquefied oils (GTLs). For example, hydrocarbons may be hydrogen-isomerized using the processes disclosed in U.S. Patent No. 6,103,099 or No. 6,180,575, or hydrocracking or hydrogen-isomerized using the processes disclosed in U.S. Patent No. 4,943,672 or No. 6,096,940, or dewaxed using the method disclosed in U.S. Patent No. 5,882,505, or hydrogen-isomerized and dewaxed using the processes disclosed in U.S. Patent No. 6,013,171, No. 6,080,301, or No. 6,165,949.

[0030] PAOs, which are API Group IV base oils, are typically derived from monomers having 4 to 30, 4 to 20, or 6 to 16 carbon atoms. Examples of PAOs that may be used in the present invention include those derived from octene, decene, or mixtures thereof. PAOs may have a kinematic viscosity of 2 to 15, 3 to 12, or 4 to 8 cSt at 100°C, as measured by ASTM D2270-10. Examples of PAOs include PAOs with a viscosity of 4 cSt at 100°C, PAOs with a viscosity of 6 cSt at 100°C, and mixtures thereof.

[0031] The base oil, in combination with additive compositions such as those disclosed in the embodiments herein, provides a lubricating oil composition for lubricating the crankcase of an internal combustion engine powered by a gaseous fuel having an ignition temperature greater than about 700 K. Therefore, the base oil may be present in the lubricating oil composition in an amount exceeding about 80% by weight, based on the total weight of the lubricating oil composition. In some embodiments, the base oil may be present in the lubricating oil composition in an amount exceeding about 85% by weight, based on the total weight of the lubricating oil composition.

[0032] Alternative combustion fuels The lubricating oil compositions herein are configured for lubricating the crankcase of an internal combustion engine powered by an alternative combustion fuel, the alternative combustion fuel being a fuel having an ignition temperature of at least about 700K, at least about 800K, or at least about 850K for the purposes of this disclosure. In other approaches, the alternative combustion fuel may have an ignition temperature of up to about 900K, up to about 880K, or up to about 860K. Such alternative combustion fuels include, but are not limited to, hydrogen fuel (ignition temperature of about 858K), which may be gaseous hydrogen fuel, and natural gas fuel (ignition temperature of about 813K), which may be compressed natural gas and / or liquefied natural gas. Preferably, the alternative combustion fuels herein suitable for use with the lubricating compositions herein include gaseous hydrogen fuel, which is burned in a gaseous state within the engine.

[0033] Other additives The lubricating oil compositions described herein may also include, in addition to the above-mentioned components, other additives of the type used in crankcase lubrication compositions. Such additives include, but are not limited to, antioxidants, viscosity modifiers, phosphorus-containing components, detergents, corrosion inhibitors, rust inhibitors, defoamers, deemulsifiers, pour point depressants, seal swelling agents, as well as additional dispersants, additional friction modifiers, and additional sulfur-containing components.

[0034] Dispersants: Lubricating oil compositions may optionally contain one or more dispersants or mixtures thereof. Dispersants are often known as ashless dispersants because they do not contain metals that form ash before being mixed into the lubricating oil composition and do not typically contribute to ash when added to the lubricant. Ashless dispersants are characterized by polar groups being bonded to hydrocarbon chains with relatively high molecular weights. Typical ashless dispersants include N-substituted long-chain alkenyl succinimides. An example of an N-substituted long-chain alkenyl succinimide is polyisobutylene succinimide, in which the number-average molecular weight of the polyisobutylene substituent is in the range of about 350 to about 50,000, or about 5,000, or about 3,000, as measured by GPC. Succinimide dispersants and their preparations are disclosed, for example, in U.S. Patent No. 7,897,696 or U.S. Patent No. 4,234,435. Alkenyl substituents can be prepared from polymerizable monomers containing about 2 to about 16 carbon atoms, or about 2 to about 8 carbon atoms, or about 2 to about 6 carbon atoms. Succinimide dispersants are typically imides formed from polyamines (typically poly(ethyleneamine)).

[0035] Preferred amines are selected from polyamines and hydroxyamines. Examples of polyamines that can be used include, but are not limited to, higher homologues such as diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), and pentaethylamine hexamine (PEHA).

[0036] A suitable heavy polyamine is a polyalkylene-polyamine mixture containing small amounts of lower polyamine oligomers such as TEPA and PEHA (pentaethylenehexamine), but mainly containing six or more nitrogen atoms, two or more primary amines per molecule, and oligomers having a broader branching range than conventional polyamine mixtures. The heavy polyamine preferably contains polyamine oligomers containing seven or more nitrogen atoms per molecule and two or more primary amines per molecule. The heavy polyamine contains more than 28% by weight (e.g., more than 32% by weight) of total nitrogen and 120 to 160 grams of primary amine groups per equivalent weight.

[0037] In some approaches, preferred polyamines are commonly known as PAMs and contain a mixture of ethyleneamines, with TEPA and pentaethylenehexamine (PEHA) being the main components of the polyamine, usually less than 80%.

[0038] Typically, PAMs contain 8.7–8.9 milliequivalents of primary amine per gram (115–112 gram equivalents per primary amine equivalent) and a total nitrogen content of approximately 33–34% by weight. Heavier cuts of PAM oligomers, which are substantially TEPA-free and contain only small amounts of PEHA, but primarily contain oligomers with more than six nitrogen atoms and broader branching, can produce dispersants with improved dispersibility.

[0039] In embodiments, the disclosure further includes at least one polyisobutylene succinimide dispersant derived from polyisobutylene having a number average molecular weight in the range of about 350 to about 50,000, or about 5,000, or about 3,000, as determined by GPC. Polyisobutylene succinimide may be used alone or in combination with other dispersants.

[0040] In some embodiments, polyisobutylene, if present, may have a terminal double bond content of more than 50 mol%, more than 60 mol%, more than 70 mol%, more than 80 mol%, or more than 90 mol%. Such PIBs are also referred to as highly reactive PIBs ("HR-PIBs"). HR-PIBs having a number-average molecular weight in the range of about 800 to about 5000 as determined by GPC are suitable for use in the embodiments of this disclosure. Conventional PIBs typically have a terminal double bond content of less than 50 mol%, less than 40 mol%, less than 30 mol%, less than 20 mol%, or less than 10 mol%.

[0041] HR-PIB having a number-average molecular weight in the range of approximately 900 to 3000, as determined by GPC, may be preferred. Such HR-PIBs are commercially available or can be synthesized by polymerization of isobutene in the presence of a non-chlorinating catalyst such as boron trifluoride, as described in U.S. Patent No. 4,152,499 by Boerzel et al. and U.S. Patent No. 5,739,355 by Gateau et al. When HR-PIB is used in the above-mentioned thermal ene reaction, it may result in a higher conversion rate and less precipitate formation during the reaction due to increased reactivity. A preferred method is described in U.S. Patent No. 7,897,696.

[0042] In one embodiment, the disclosure further comprises at least one dispersant derived from polyisobutylene succinic anhydride, "PIBSA". PIBSA may have an average succinic acid moiety of about 1.0 to about 2.0 per polymer. The active ingredient % of alkenyl or alkyl succinic anhydride can be determined using chromatographic techniques. This method is described in columns 5 and 6 of U.S. Patent No. 5,334,321. The conversion percentage of polyolefin is calculated from the active ingredient % using the formulas in columns 5 and 6 of U.S. Patent No. 5,334,321. Unless otherwise stated, all percentages are weight percentages, and all molecular weights are number-average molecular weights determined by gel permeation chromatography (GPC) using commercially available polystyrene standards (with a number-average molecular weight of 180 to about 18,000 as a calibration standard).

[0043] In one embodiment, the dispersant may be derived from polyalphaolefin (PAO) succinic anhydride. In one embodiment, the dispersant may be derived from olefin maleic anhydride copolymer. As an example, the dispersant may be described as poly-PIBSA. In an embodiment, the dispersant may be derived from an anhydride grafted onto an ethylene-propylene copolymer.

[0044] A suitable class of nitrogen-containing dispersants can be derived from olefin copolymers (OCPs), more specifically from ethylene-propylene dispersants that can be grafted with maleic anhydride. A more complete list of nitrogen-containing compounds that can be reacted with functionalized OCPs is described and / or commercially available in U.S. Patents Nos. 7,485,603, 7,786,057, 7,253,231, 6,107,257, and 5,075,383.

[0045] One class of suitable dispersants may also be Mannich bases. Mannich bases are materials formed by the condensation of higher molecular weight alkyl-substituted phenols, polyalkylene polyamines, and aldehydes such as formaldehyde. Mannich bases are described in detail by U.S. Patent No. 3,634,515.

[0046] A suitable class of dispersants may also be high molecular weight esters or semi-esteramides. Suitable dispersants may also be post-treated by conventional methods with any of a variety of agents. These include boron, urea, thiourea, dimercaptothiadiazole, carbon disulfide, aldehydes, ketones, carboxylic acids, hydrocarbon-substituted succinic anhydride, maleic anhydride, nitriles, epoxides, carbonates, cyclic carbonates, hindered phenol esters, and phosphorus compounds. U.S. Patents 7,645,726, 7,214,649, and 8,048,831 are incorporated herein by reference in their entirety.

[0047] In addition to the post-treatment of carbonates and boric acid, each compound may be post-treated or further post-treated by a variety of post-treatments designed to improve or impart different properties. Such post-treatments include those summarized in columns 27-29 of U.S. Patent No. 5,241,003, which is incorporated herein by reference. Such treatments include treatment by: inorganic phosphoric acid or anhydride (e.g., U.S. Patents No. 3,403,102 and No. 4,648,980), organophosphorus compounds (e.g., U.S. Patent No. 3,502,677), phosphorus pentasulfide, boron compounds as already described above (e.g., U.S. Patents No. 3,178,663 and No. 4,652,387), carboxylic acids, polycarboxylic acids, anhydrides, and / or acid halides (e.g., U.S. Patents No. 3,708,522 and No. 4,9 (Patent No. 48,386), epoxides, polyepoxyates, or thioepoxides (e.g., U.S. Patents No. 3,859,318 and 5,026,495), aldehydes or ketones (e.g., U.S. Patent No. 3,458,530), carbon disulfide (e.g., U.S. Patent No. 3,256,185), glycidol (e.g., U.S. Patent No. 4,617,137), urea, thiourea, or guanidine (e.g., U.S. Patents No. 3,312,619 and 3,865,813, and British Patent No. 1,065) ,595), organic sulfonic acids (e.g., U.S. Patent No. 3,189,544 and UK Patent No. 2,140,811), alkenyl cyanides (e.g., U.S. Patents No. 3,278,550 and No. 3,366,569), diketenes (e.g., U.S. Patent No. 3,546,243), diisocyanates (e.g., U.S. Patent No. 3,573,205), alkansultones (e.g., U.S. Patent No. 3,749,695), 1,3-dicarbonyl compounds (e.g., U.S. Patent No. 4,579,675) U.S. Patent No. 4,617,138, 4,645,515, 4,668,246, 4,963,275, and 4,971,711), cyclic carbonates or thiocarbonates, linear monocarbonates or polycarbonates, or chloroformates (e.g., U.S. Patent No. 4,612,132, 4,647,(Patents No. 390, No. 4,648,886, No. 4,670,170), nitrogen-containing carboxylic acids (e.g., U.S. Patent No. 4,971,598 and UK Patent No. 2,140,811), hydroxy-protected chlorodicarbonyloxy compounds (e.g., U.S. Patent No. 4,614,522), lactams, thiolactams, thiolactones, or dithiolactones (e.g., U.S. Patents No. 4,614,603 and No. 4,666,460), cyclic carbonates or thiocarbonates, linear monocarbonates or polycarbonates, or chloroformates (e.g., U.S. Patent Nos. 4,612,132, 4,647,390, 4,646,860, and 4,670,170), nitrogen-containing carboxylic acids (e.g., U.S. Patent No. 4,971,598 and UK Patent No. 2,440,811), hydroxy-protected chlorodicarbonyloxy compounds (e.g., U.S. Patent No. 4,614,522), lactams, thiolactams, thiolactones, or dithiolactones (e.g., U.S. Patents No. 4,614,603 and 4,666,460), cyclic carbamates, cyclic thiocarbamates, or cyclic dithiocarbamates (e.g., U.S. Patent Nos. 4,663,062 and 4,666,459), hydroxyaliphatic carboxylic acids (e.g., U.S. Patents Nos. 4,482,464, 4,521,318 and 4,713,189), oxidizing agents (e.g., U.S. Patent No. 4,379,064), combinations of phosphorus pentasulfide and polyalkylene polyamines (e.g., U.S. Patent No. 3,185,647), combinations of carboxylic acids or aldehydes or ketones and sulfur or sulfur chloride (e.g., U.S. Patents Nos. 3,390,086 and 3,470,098), hydrazine and disulfide Combinations of carbon (e.g., U.S. Patent No. 3,519,564), combinations of aldehydes and phenols (e.g., U.S. Patents No. 3,649,229, 5,030,249, and 5,039,307), combinations of aldehydes and O-diesters of dithiophosphate (e.g., U.S. Patent No. 3,865,740), combinations of hydroxyaliphatic carboxylic acids and boric acid (e.g., U.S. Patent No. 4,554,086), combinations of hydroxyaliphatic carboxylic acids followed by formaldehyde and phenol (e.g., U.S. Patent No. 4,636,(e.g., U.S. Patent No. 322), combinations of hydroxyaliphatic carboxylic acids and subsequent aliphatic dicarboxylic acids (e.g., U.S. Patent No. 4,663,064), combinations of formaldehyde and phenol and subsequent glycolic acid (e.g., U.S. Patent No. 4,699,724), combinations of hydroxyaliphatic carboxylic acids or oxalic acid and subsequent diisocyanates (e.g., U.S. Patent No. 4,713,191), combinations of inorganic acids or anhydrides of phosphorus or their partial or whole sulfur analogs and boron compounds (e.g., U.S. Patent No. 4,857,21 (4) Combinations of organic diacids, followed by unsaturated fatty acids, followed by nitroso aromatic amines, optionally followed by boron compounds, and subsequently glycolating agents (e.g., U.S. Patent No. 4,973,412), combinations of aldehydes and triazoles (e.g., U.S. Patent No. 4,963,278), combinations of aldehydes and triazoles, followed by boron compounds (e.g., U.S. Patent No. 4,981,492), and combinations of cyclic lactones and boron compounds (e.g., U.S. Patents No. 4,963,275 and 4,971,711). In this specification, the patents mentioned above are incorporated herein in their entirety.

[0048] A suitable dispersant may have a TBN of approximately 5 to 30 TBN when measured in a dispersant sample containing approximately 50% diluted oil, and may be a dispersant of approximately 10 to 65 mg KOH / g on an oil-free basis. TBN is measured by the method of ASTM D2896.

[0049] In further embodiments, the optional dispersion additive may be a hydrocarbyl-substituted succinamide or succinimide dispersant. In some approaches, the hydrocarbyl-substituted succinamide or succinimide dispersant may be derived from a hydrocarbyl-substituted acylating agent reacted with a polyalkylene polyamine, where the hydrocarbyl substituent of the succinamide or succinimide dispersant is a linear or branched hydrocarbyl group having a number-average molecular weight of about 250 to about 5,000 when measured by GPC using polystyrene as the calibration standard.

[0050] In some approaches, the polyalkylene polyamine used to form the dispersant has the following formula:

[0051] [ka] In the formula, each R and R' is independently a divalent C1-C6 alkylene linker, each R1 and R2 independently forms a 5-membered or 6-membered ring by being fused with one or more aromatic or non-aromatic rings, either with hydrogen, a C1-C6 alkyl group, or the nitrogen atom to which they are bonded, and n is an integer from 0 to 8. Another approach is to select polyalkylene polyamines from the group consisting of mixtures of polyethylene polyamines having an average of 5-7 nitrogen atoms, triethylenetetramine, tetraethylenepentamine, and combinations thereof.

[0052] If present, the dispersant may be used in an amount sufficient to provide up to about 20% by weight, based on the final weight of the lubricating oil composition. Other amounts of dispersant that may be used may be about 0.1% to about 15% by weight, or about 0.1% to about 10% by weight, about 0.1% to about 8% by weight, or about 1% to about 10% by weight, or about 1% to about 8% by weight, or about 1% to about 6% by weight, based on the final weight of the lubricating oil composition. In some embodiments, the lubricating oil composition utilizes a mixed dispersant system. A single type or a mixture of two or more types of dispersants in any desired ratio may be used.

[0053] Anti-wear agents: The lubricating oil compositions herein may also optionally contain one or more anti-wear agents. Examples of suitable anti-wear agents include, but are not limited to, metal thiophosphates; metal dialkyldithiophosphates; phosphate esters or salts thereof; phosphate esters; phosphites; phosphorus-containing carboxylic acid esters, ethers, or amides; sulfurized olefins; thiocarbamate-containing compounds such as thiocarbamate esters, alkylene-linked thiocarbamates, dithiocarbamates, and / or bis(S-alkyldithiocarbamyl) disulfides; and mixtures thereof. Suitable anti-wear agents may be molybdenum dithiocarbamate, bis(dialkyl-dithiocarbamate), or alkylene bis(dialkyl-dithiocarbamate) and similar anti-wear agents. Phosphorus-containing anti-wear agents are fully described in European Patent No. 612839. The metal in the dialkyldithiophosphate salt may be an alkali metal, an alkaline earth metal, aluminum, lead, tin, molybdenum, manganese, nickel, copper, titanium, or zinc. A useful wear-resistant agent may be zinc dialkyldithiophosphate.

[0054] Further examples of suitable abrasion resistant agents include titanium compounds, tartrates, tartrimides, oil-soluble amine salts of phosphorus compounds, sulfurized olefins, phosphates (e.g., dibutylphosphite), phosphonates, thiocarbamate-containing compounds such as thiocarbamate esters, thiocarbamate amides, thiocarbamate ethers, alkylene-linked thiocarbamates, and bis(S-alkyldithiocarbamyl) disulfides. Tartarates or tartrimides may contain alkyl ester groups, and the total number of carbon atoms on the alkyl group may be at least 8. In one embodiment, the abrasion resistant agent may include citrates.

[0055] The anti-wear agent may be present in a range of about 0% to about 15% by weight, or about 0.01% to about 10% by weight, or about 0.05% to about 5% by weight, or about 0.1% to about 3% by weight of the lubricating oil composition. In other embodiments, the compositions herein may further contain one or more oil-soluble molybdenum compounds, if present, providing molybdenum of about 200 ppm or less, less than about 150 ppm, less than about 100 ppm, or less than about 50 ppm.

[0056] Antioxidants: In some embodiments, the lubricating oil compositions of this specification may contain one or more antioxidants. Suitable antioxidants include, in particular, phenolic antioxidants, aromatic amine antioxidants, sulfur-containing antioxidants, and organic phosphites.

[0057] Examples of phenolic antioxidants include 2,6-di-tert-butylphenol, liquid mixtures of tributylated phenols, 2,6-di-tert-butyl-4-methylphenol, 4,4'-methylenebis(2,6-di-tert-butylphenol), 2,2'-methylenebis(4-methyl-6-ter-t-butylphenol), and mixed methylene crosslinked polyalkylphenols, as well as 4,4'-thiobis(2-methyl-6-tert-butylphenol), N,N'-di-sec-butylphenylenediamine, 4-isopropylaminodiphenylamine, phenyl-alpha-naphthylamine, and cyclic alkylated diphenylamines. Examples include sterically hindered tertiary butylated phenols, bisphenols, and cinnamic acid derivatives, as well as combinations thereof.

[0058] Examples of aromatic amine antioxidants include, but are not limited to, diarylamines having the following formulas.

[0059] [ka] In the formula, R' and R'' each independently represent a substituted or unsubstituted aryl group having 6 to 30 carbon atoms. Examples of substituents on the aryl group include aliphatic hydrocarbon groups such as alkyl groups, hydroxyl groups, halogen radicals, carboxylic acid or ester groups, or nitro groups, all having 1 to 30 carbon atoms.

[0060] The aryl group is preferably a substituted or unsubstituted phenyl or naphthyl, and in particular, one or both of the aryl groups are substituted with at least one alkyl group having 4 to 30 carbon atoms, preferably 4 to 18 carbon atoms, most preferably 4 to 9 carbon atoms. It is preferable that one or both of the aryl groups are substituted, for example, monoalkylated diphenylamine, dialkylated diphenylamine, or a mixture of mono- and dialkylated diphenylamine.

[0061] Examples of diarylamines that may be used include, but are not limited to, diphenylamine; various alkylated diphenylamines, 3-hydroxydiphenylamine, N-phenyl-1,2-phenylenediamine, N-phenyl-1,4-phenylenediamine, monobutyldiphenylamine, dibutyldiphenylamine, monooctyldiphenylamine, dioctyldiphenylamine, monononyldiphenylamine, dinonyldiphenylamine, monotetradecyldiphenylamine, ditetradecyldiphenylamine, phenyl-alpha-naphthylamine, monooctylphenyl-alpha-naphthylamine, phenyl-beta-naphthylamine, monoheptyldiphenylamine, diheptyldiphenylamine, p-oriented styrene-diphenylamine, mixed butyloctyldiphenylamine, and mixed octylstyryldiphenylamine.

[0062] Sulfur-containing antioxidants include, but are not limited to, sulfurized olefins, characterized by the type of olefin used in their production and the final sulfur content of the antioxidant. High molecular weight olefins, i.e., olefins having an average molecular weight of 168 to 351 g / mol, are preferred. Examples of olefins that can be used include alpha-olefins, isomerized alpha-olefins, branched-chain olefins, cyclic olefins, and combinations thereof.

[0063] As alpha-olefins, any C4-C 25 Examples include, but are not limited to, alpha-olefins. Alpha-olefins can be isomerized before or during the sulfidation reaction. Structural and / or conformational isomers of alpha-olefins containing internal double bonds and / or branching can also be used. For example, isobutylene is the branched olefin counterpart of alpha-olefin 1-butene.

[0064] Sulfur sources that can be used in the sulfurization reaction of olefins include elemental sulfur, sulfur monochloride, sulfur dichloride, sodium sulfide, sodium polysulfide, and mixtures thereof that are added together at different stages of the sulfurization process.

[0065] Unsaturated oils can also be sulfurized and used as antioxidants due to their unsaturation. Examples of oils or fats that can be used include corn oil, canola oil, cottonseed oil, grape seed oil, olive oil, palm oil, peanut oil, coconut oil, rapeseed oil, safflower seed oil, sesame seed oil, soybean oil, sunflower seed oil, animal fat, and combinations thereof.

[0066] The total amount of antioxidants in the lubricating oil compositions described herein may be present in an amount that delivers a maximum of approximately 200 ppm of nitrogen, or a maximum of approximately 150 ppm of nitrogen, or approximately 100 to approximately 150 ppm of nitrogen.

[0067] Friction modifiers: In some embodiments, the lubricating oil compositions herein may also contain additional friction modifiers other than those contained in the friction modifier system described above. Suitable additional friction modifiers may include metal-containing and metal-free friction modifiers, and suitable friction modifiers include, but are not limited to, imidazolines, amides, amines, succinimides, alkoxylated amines, alkoxylated etheramines, amine oxides, amidoamines, nitriles, betaines, quaternary amines, imines, amine salts, aminoguanidines, alkanolamides, phosphonates, metal-containing compounds, glycerol esters, sulfurized fatty compounds and olefins, sunflower oil, other naturally occurring vegetable or animal oils, dicarboxylic acid esters, polyol esters or partial esters, and one or more aliphatic or aromatic carboxylic acids.

[0068] Suitable friction modifiers may contain hydrocarbyl groups selected from linear, branched, or aromatic hydrocarbyl groups, or mixtures thereof, and such hydrocarbyl groups may be saturated or unsaturated. Hydrocarbyl groups may consist of carbon and a heteroatom such as hydrogen or sulfur or oxygen. Hydrocarbyl groups may range from 12 to 25 carbon atoms. In some embodiments, the friction modifier may be a long-chain fatty acid ester. In other embodiments, the long-chain fatty acid ester may be a mono-ester, di-ester, or (tri)glyceride. Friction modifiers may be long-chain fatty amides, long-chain fatty esters, long-chain fatty epoxide derivatives, or long-chain imidazolines.

[0069] Other suitable friction modifiers may include organic, ashless (metal-free), and nitrogen-free organic friction modifiers. Such friction modifiers may contain esters formed by reacting a carboxylic acid and an anhydride with an alkanol, and may generally contain polar end groups (e.g., carboxyl or hydroxyl) covalently bonded to a lipophilic hydrocarbon chain. An example of an organic, ashless, nitrogen-free friction modifier is commonly known as glycerol monooleate (GMO), which may contain mono-, di-, and tri-esters of oleic acid. Other suitable friction modifiers are described in U.S. Patent No. 6,723,685.

[0070] Amineral friction modifiers may include amines or polyamines. Such compounds may have hydrocarbyl groups that are either saturated or unsaturated linear, or mixtures thereof, and may contain 12 to 25 carbon atoms. Further examples of suitable friction modifiers include alkoxylated amines and alkoxylated etheramines. Such compounds may have hydrocarbyl groups that are either linear, saturated, unsaturated, or mixtures thereof. These may contain about 12 to about 25 carbon atoms. Examples include ethoxylated amines and ethoxylated etheramines.

[0071] Amines and amides may be used on their own or as adducts or reaction products with boron compounds such as boron oxide, boron halides, metaborates, boric acid, or mono-, di-, or tri-alkylborates. Other suitable friction modifiers are described in U.S. Patent No. 6,300,291.

[0072] If the additional friction modifier contains nitrogen, such additional friction modifier may be present in the lubricating oil composition in any amount, provided that the performance requirements are not impaired.

[0073] Corrosion inhibitors: Other rust inhibitors or corrosion inhibitors may also be included in the lubricating oil compositions described herein. Such materials include monocarboxylic acids and polycarboxylic acids. Examples of preferred monocarboxylic acids are octanoic acid, decanoic acid, and dodecanoic acid. Examples of preferred polycarboxylic acids include dimers and trimers produced from tall oil fatty acids, oleic acid, linoleic acid, and other acids.

[0074] Other useful types of rust inhibitors include alkenyl succinic acids and alkenyl succinic anhydride corrosion inhibitors, such as tetrapropenyl succinic acid, tetrapropenyl succinic anhydride, tetradecenyl succinic acid, tetradecenyl succinic anhydride, hexadecenyl succinic acid, and hexadecenyl succinic anhydride. Semi-esters of alkenyl succinic acids having 8 to 24 carbon atoms in the alkenyl group with alcohols such as polyglycols are also useful. Other suitable rust inhibitors or corrosion inhibitors include etheramines, acidic phosphoric acid, amines, polyethoxylated compounds such as ethoxylated amines, ethoxylated phenols, and ethoxylated alcohols, imidazolines, aminosuccinic acid, or derivatives thereof. Mixtures of such rust inhibitors or corrosion inhibitors may be used. The total amount of corrosion inhibitors present in the lubricating compositions described herein may be up to 2.0% by weight, or in the range of 0.01 to 1.0% by weight, based on the total weight of the lubricating composition.

[0075] Viscosity modifiers: The lubricating oil composition may optionally contain one or more viscosity modifiers. Suitable viscosity modifiers include polyolefins, olefin copolymers, ethylene / propylene copolymers, polyisobutene, styrene-isoprene polymers, styrene / maleate copolymers, styrene-butadiene copolymers, styrene-isoprene polymers, alpha-olefin maleic anhydride copolymers, polymethacrylates, polyacrylates, polyalkylstyrenes, hydrated alkenylaryl conjugated diene copolymers, or mixtures thereof. Viscosity modifiers may also contain star polymers, a suitable example of which is described in U.S. Patent Application Publication No. 2012 / 0101017(A1).

[0076] The lubricating oil compositions described herein may also optionally contain one or more dispersing viscosity modifiers in addition to, or in place of, the viscosity modifiers. Suitable dispersing viscosity modifiers include functionalized polyolefins, such as ethylene-propylene copolymers functionalized with the reaction product of an acylating agent (such as maleic anhydride) and an amine, amine-functionalized polymethacrylates, or esterified maleic anhydride-styrene copolymers reacted with an amine.

[0077] Viscosity modifiers and / or dispersants: The total amount of viscosity modifiers, if present, may be up to about 1.0% by weight, or up to about 0.5% by weight, or up to about 0.3% by weight, based on the total weight of the lubricating oil composition.

[0078] Demulsifiers: Demulsifiers may also be included in the compositions herein, and such demulsifiers may include trialkyl phosphates, as well as various polymers and copolymers of ethylene glycol, ethylene oxide, and propylene oxide, or mixtures thereof, including polyethylene oxide, polypropylene oxide, and (ethylene oxide-propylene oxide) polymers. If present, the amount of demulsifier in the lubricating oil composition may be up to about 0.05% by weight, up to about 0.02% by weight, or less than about 0.015% by weight, based on the total weight of the lubricating oil composition.

[0079] Defoaming agents. Defoaming agents used to reduce or prevent the formation of stable foam include silicones, polyacrylates, or organic polymers. Defoaming agents that may be useful in the compositions of the disclosed invention include polysiloxanes, copolymers of ethyl acrylate and 2-ethylhexyl acrylate, and optionally vinyl acetate. If present, the amount of defoaming agent in the lubricating oil composition may be up to about 0.1% by weight, up to about 0.05% by weight, or less than about 0.04% by weight, based on the total weight of the lubricating oil composition.

[0080] Pour point depressants: The lubricating oil compositions described herein may optionally contain one or more pour point depressants. Suitable pour point depressants include maleic anhydride-styrene esters, polymethacrylates, polymethyl methacrylates, polyacrylates, or polyacrylamides, or mixtures thereof. If a pour point depressant is present, it may be present in an amount of about 0.001% to about 0.04% by weight, based on the total weight of the lubricant.

[0081] Generally speaking, the lubricating oil compositions described herein may contain additive components within the range listed in Table 2.

[0082] [Table 2]

[0083] The proportions of each component described above represent the weight percentage of each component based on the total weight of the lubricating oil composition containing the components described herein. The additives used in formulating the compositions described herein may be blended with the base oil individually or in various partial combinations. However, it may be preferable to blend all components simultaneously using an additive concentrate (i.e., the additive plus a diluent such as a hydrocarbon solvent). The use of an additive concentrate takes advantage of the intercompatibility provided by the combination of components when they are in the form of an additive concentrate. Furthermore, the use of concentrates reduces mixing time and the possibility of mixing errors.

[0084] Unless otherwise indicated in the context of the discussion herein, the following definitions of terms are provided to clarify the meaning of specific terms used herein.

[0085] The terms “lubricating oil,” “lubricant composition,” “lubricant composition,” “lubricant,” and “lubricating oil composition” refer to a final lubrication product comprising a majority of base oil and a trace amount of additive composition. As used herein, “majority” means at least 50 percent by weight, and “trace amount” means less than 50 percent by weight.

[0086] As used herein, the terms “additive package,” “additive concentrate,” and “additive composition” refer to the portion of the lubricating oil composition excluding the majority of the base oil.

[0087] As used herein, the terms “hydrocarbyl substituent” or “hydrocarbyl group” are used in their ordinary sense, as is well known to those skilled in the art. Specifically, they refer to a group having carbon atoms directly bonded to the rest of the molecule and having primarily hydrocarbon characteristics. Each hydrocarbyl group is independently selected from the hydrocarbon substituents, the substituted hydrocarbon substituents comprising one or more of the following: halo, hydroxyl, alkoxy, mercapto, nitro, nitroso, amino, pyridyl, furyl, imidazolyl, oxygen, and nitrogen, and two or fewer non-hydrocarbon substituents present for every 10 carbon atoms in the hydrocarbyl group.

[0088] As used herein, the terms “percent by weight” or “wt%” mean the percentage of the listed components relative to the total weight of the composition, unless otherwise specified.

[0089] As used herein, the terms “soluble,” “oil-soluble,” and “dispersible” may indicate, but do not necessarily, that a compound or additive is soluble, soluble, miscible, or suspendable in oil in all proportions. However, the aforementioned terms mean that they are soluble, suspendable, soluble, or stably dispersible in oil to a degree sufficient to exert their intended effect, for example, in an environment in which oil is used. Furthermore, if desired, it may be possible to incorporate higher levels of specific additives by incorporating other additives.

[0090] As used herein, the term "alkyl" refers to a linear, branched, cyclic, and / or substituted saturated chain portion of about 1 to about 200 carbon atoms.

[0091] As used herein, the term “alkenyl” refers to a linear, branched, cyclic, and / or substituted saturated chain portion comprising approximately 3 to approximately 30 carbon atoms.

[0092] As used herein, the term "aryl" refers to monocyclic and polycyclic aromatic compounds that may include, for example, nitrogen and oxygen, alkylaryl, amino, hydroxyl, alkoxy, halo substituents, and / or heteroatoms.

[0093] As used herein, "number-average molecular weight" or "Mn" is determined by gel permeation chromatography (GPC) using commercially available polystyrene standards (with Mn values ​​of approximately 180 to 18,000 as calibration standards).

[0094] Throughout this disclosure, terms such as “comprises,” “includes,” and “contains” are considered open-ended and should be understood to include any elements, processes, or components that are not expressly enumerated. The phrase “consisting essentially of” means including any expressly enumerated elements, processes, or components, and any additional elements, processes, or components that do not substantially affect the basic and novel aspects of the invention. This disclosure also intends that any composition described using the terms “comprises,” “includes,” or “contains” should also be interpreted as including disclosures of the same composition that “consisting of” or “essentially of” those components that are specifically enumerated. [Examples]

[0095] A better understanding of this disclosure and its many advantages can be made clear by the following examples. The following examples are illustrative and not limiting in any way to its scope or intent. Those skilled in the art will readily understand that variations of the components, methods, steps, and devices described in these examples can be used. Unless otherwise stated, or unless evident from the context of the discussion in the following examples and throughout this disclosure and the claims, all percentages, ratios, and parts mentioned in this disclosure are by weight. Any standardized test method described in the examples, disclosure, or claims refers to a version of the test method that was publicly published at the time of filing of this disclosure, unless evident from the context of its use.

[0096] The examples herein evaluate mean stochastic pre-ignition (SPI) events at FEV Europe GmbH using a 7.7-liter medium-load 6-cylinder inline H2 engine (H2 fuel has an autoignition temperature of approximately 850K–858K) with an average peak cycle pressure of 160 bar and a maximum peak cycle pressure of 180 bar. The crank angle was adjusted to match the combustion center of the target to neither promote nor mitigate SPI. SPI was evaluated by measuring the SPI count in each cylinder over a total of 150 measurements at a mean effective pressure (BMEP) of 12 bar and 1000 rpm. Each measurement included 500 cycles for each cylinder. The average SPI of the engine per 500 cycles was determined by calculating the average events across all six cylinders.

[0097] Table 3 below lists the lubricants of the first set, namely Comparative Lubricants 1-3 and Lubricants 1-2 of the present invention. The lubricants contained the same base additive package containing the same amounts and types of dispersants, antioxidants, defoamers, friction modifiers, and viscosity modifiers. Only the detergent system and ZDDP anti-wear additive were varied between the lubricants as shown in Table 3 below. The process oil in the base package was slightly varied to account for the variation in the treatment rate of the detergent system. The lubricants were blended in the same base oil blend of API Group II base oils and had a kV of approximately 14 cSt at 100°C.

[0098] Table 4 below describes Invention 3, an additional lubricant. This lubricant contained a different base additive package and included a variation of the detergent system of the present invention. This formulation was tested in API Group II base oils at its treatment rate to obtain a final fluid having approximately 15 cSt at kV 100°C.

[0099] Table 5 details the differences arising from changes in the detergent system (i.e., the amount of calcium and magnesium delivered to the lubricant), the TBN of the lubricant (ASTM D2896), and the measured sulfated ash content of the lubricant (ASTM D874). The detergents used in the lubricants in these examples are as follows: • Cleaning agent additive 1 (Det-1): A perbasic calcium sulfonate cleaning agent containing approximately 300 TBN (measured by ASTM D2896) and approximately 11.9% by weight of calcium. • Cleaning agent additive 2 (Det-2): A low-basic to neutral calcium sulfonate cleaning agent containing approximately 25-50 TBN (measured by ASTM D2896) and approximately 2.7% by weight of calcium. • Cleaning agent additive 3 (Det-3): A perbasic calcium phenate cleaning agent containing approximately 250 TBN (measured by ASTM D2896) and approximately 9.25% by weight of calcium. • Cleaning agent additive 4 (Det-4): A perbasic magnesium sulfonate cleaning agent containing approximately 400 TBN (measured by ASTM D2896) and approximately 9.6% by weight of magnesium.

[0100] [Table 3]

[0101] [Table 4] * Additional additives may include antioxidants, defoamers, process oils, and pour point depressants.

[0102] [Table 5] * Exemplary mmol calculation of Invention 3: 0.741 g of Det 4 × 9.6 wt% Mg = approximately 0.0711 g of Mg / 0.0234 g / mmol = approximately 3.04 mmol of metal delivered from the overbasic sulfonate detergent to the lubricant. The amounts of other metals are determined similarly. ** Calculation of an exemplary ratio of Invention 3: (3.04 mmol of metal from overbasic sulfonate detergent / (3.04 mmol + 3.10 mmol + 0.03 mmol)) / 10 TBN = approximately 0.05 ratio.

[0103] [Table 6] * ASTM D8291 evaluated each lubricant composition in a conventional gasoline-fueled engine.

[0104] As shown by comparative lubricant samples 1-3 in Tables 5 and 6 (and Figure 1), when the metal delivered from the overbasic sulfonate detergent is not precisely balanced with respect to the total detergent metal and / or the percentage of metal from the overbasic sulfonate detergent relative to TBN (e.g., mmol of metal and / or comparative ratio greater than 0.07, as shown in Tables 5 and Figure 1), the average SPI is unacceptably high (e.g., greater than 6) when the lubricant is used in a hydrogen fuel internal combustion engine. However, as shown by comparative lubricant samples 1-3 in Tables 5 and 6 (and Figure 1), when the metal delivered from the overbasic sulfonate detergent is precisely balanced with respect to the total detergent metal and / or the percentage of metal from the overbasic sulfonate detergent relative to TBN (e.g., selected mmol of metal and / or ratio of 0.07 or less, as shown in Tables 5 and Figure 1), the average SPI event is minimized (e.g., 6 or less) when the lubricant is used in a hydrogen fuel internal combustion engine. Figure 1 also shows improvements in SPI in embodiments that include a precisely balanced percentage ratio of overbasic sulfonate metals relative to TBN, which is suitable for alternative fuel engines, particularly hydrogen fuel engines. The data in Table 6 also shows that lubricants that pass LSPI sequence IX (ASTM D8291) in conventional gasoline engines do not necessarily achieve passing SPI in hydrogen fuel internal combustion engines.

[0105] The lubricating compositions of this disclosure are described in detail and in the abstract herein, but the foregoing description should be understood to describe, and not limit, the scope of this disclosure as defined by the appended claims. Other embodiments, advantages, and modifications are within the scope of the claims. This specification and examples are for illustrative purposes only, and the true scope of this disclosure is intended to be shown by the following claims.

[0106] Other embodiments of this disclosure will become apparent to those skilled in the art from consideration of this specification and the practice of the embodiments disclosed herein. Where used throughout the specification and claims, “a” and / or “an” may refer to one or more. Unless otherwise indicated, all figures used herein to describe properties such as amounts, molecular weights, percentages, ratios, and reaction conditions of components should be understood in all cases as being modified by the term “approximately,” whether or not the term “approximately” is present. Thus, unless otherwise indicated, the numerical parameters described herein are approximations that may vary depending on the desired properties to be obtained by this disclosure. Each numerical parameter should be interpreted at least in terms of the number of significant figures reported and by applying ordinary rounding techniques, not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims. Although the numerical ranges and parameters describing the broad disclosure are approximations, the numerical values ​​described in specific examples are reported as accurately as possible. However, any numerical value inherently contains certain errors that inevitably arise from the standard deviation found in their respective test measurements.

[0107] It should be understood that each component, compound, substituent, or parameter disclosed herein is disclosed for use alone or in combination with any one or more other components, compounds, substituents, or parameters disclosed herein.

[0108] It should be further understood that each range disclosed herein should be interpreted as a disclosure of each specific value within the disclosure range having the same number of significant figures. Therefore, the range 1–4 should be interpreted as a clear disclosure of the values ​​1, 2, 3, and 4, as well as any range of values ​​such as 1–4, 1–3, 1–2, 2–4, 2–3, etc.

[0109] It should be further understood that each lower limit of each range disclosed herein should be interpreted as being disclosed in combination with each upper limit of each range and each specific value within each range disclosed herein for the same component, compound, substituent, or parameter. Therefore, this disclosure should be interpreted as a disclosure of all ranges derived by combining each lower limit of each range with each upper limit of each range or each specific value within each range, or by combining each upper limit of each range with each specific value within each range.

[0110] Furthermore, any specific amounts / values ​​of components, compounds, substituents, or parameters disclosed in the description or examples should be interpreted as disclosures of either a lower or upper limit of a range, and can therefore be combined with any other lower or upper limit or specific amounts / values ​​in the range for the same component, compound, substituent, or parameter disclosed elsewhere in this application to form a range for that component, compound, substituent, or parameter.

Claims

1. A lubricating oil composition configured for lubricating an internal combustion engine that operates on a fuel having an ignition temperature of over approximately 700K, One or more base oils with lubricating viscosity, It is a cleaning agent, (i) at least one overbasic metal-containing sulfonate detergent that provides the composition with about 2 to about 8 mmol of metal, (ii) At least one neutral to low basic metal-containing sulfonate detergent that provides at least about 0.02 mmol of metal to the composition, (iii) A cleaning agent system comprising: at least one overbasic metal-containing phenate cleaning agent that provides the composition with up to approximately 4 mmol of metal; The lubricating oil composition is a lubricating oil composition having a total base number (TBN) of at least about 9.5, as measured in accordance with ASTM D2896.

2. The lubricating oil composition according to claim 1, wherein the ratio of the percentage of metal provided by the overbasic metal-containing sulfonate detergent to the TBN (ASTM D2896) of the lubricating oil composition is about 0.07 or less, and / or the TBN of the lubricating oil composition is about 10 to about 15 when measured in accordance with ASTM D2896, and / or the detergent system comprises at least an overbasic metal-containing sulfonate detergent, at least an overbasic metal-containing phenate detergent, or a combination thereof, and each overbasic detergent has at least about 200 TBN (ASTM D2896).

3. The lubricating oil composition according to claim 1, wherein the lubricating oil composition has a sulfated ash (SASH) content of more than 0.9 weight percent when measured in accordance with ASTM D874, or the lubricating oil composition has a sulfated ash (SASH) content of more than 1.2 weight percent when measured in accordance with ASTM D874.

4. The lubricating oil composition according to claim 1, further comprising one or more oil-soluble molybdenum compounds, wherein the cleaning agent system provides about 1,000 to about 5,000 ppm of calcium, and / or the cleaning agent system provides about 10 to about 800 ppm of magnesium, and / or the composition provides about 200 ppm or less of molybdenum.

5. The lubricating oil composition according to claim 1, wherein one or more base oils of the aforementioned lubricating viscosity include a base oil of API group I, a base oil of API group II, or a combination thereof.

6. The lubricating oil composition according to claim 1, wherein the composition is configured to lubricate an internal combustion engine powered by a fuel having an ignition temperature of over 800 K, or the composition is configured to lubricate an internal combustion engine powered by a fuel having an ignition temperature of over 850 K, or the fuel having an ignition temperature of over 700 K is hydrogen fuel, and / or the lubricating oil composition has an average measured SPI of about 6 stochastic pre-ignition (SPI) counts or less at a net mean effective pressure (BMEP) of 1000 rpm and 12 bar.

7. A method for lubricating an internal combustion engine when operating with a fuel having an ignition temperature of over approximately 700K, in order to mitigate abnormal combustion events, This includes lubricating the crankcase of an internal combustion engine with a lubricating oil composition, and burning a fuel having an ignition temperature of over approximately 700K in the internal combustion engine, The method comprising: (i) one or more base oils of lubricating viscosity; and (ii) a detergent system comprising: (iiia) at least one overbasic metal-containing sulfonate detergent that provides about 2 to about 8 mmol of metal to the composition; (iiib) at least one neutral to low-basic metal-containing sulfonate detergent that provides at least about 0.02 mmol of metal to the composition; and (iic) at least one overbasic metal-containing phenate detergent that provides up to about 4 mmol of metal to the composition, wherein the lubricating composition has a total base number (TBN) of at least about 9.5 as measured in accordance with ASTM D2896.

8. The method according to claim 7, wherein the ratio of the percentage of metal provided by the overbasic metal-containing sulfonate detergent to the TBN (ASTM D2896) of the lubricating oil composition is about 0.07 or less, and / or the TBN of the lubricating oil composition is about 10 to about 15 when measured in accordance with ASTM D2896, and / or the detergent system comprises at least an overbasic metal-containing sulfonate detergent, at least an overbasic metal-containing phenate detergent, or a combination thereof, each overbasic detergent having at least about 200 TBN (ASTM D2896).

9. The method according to claim 7, wherein the lubricating oil composition has a sulfated ash (SASH) content of more than 0.9 weight percent when measured in accordance with ASTM D874, or the lubricating oil composition has a sulfated ash (SASH) content of more than 1.2 weight percent when measured in accordance with ASTM D874.

10. The method according to claim 7, further comprising one or more oil-soluble molybdenum compounds, wherein the cleaning agent system provides about 1,000 to about 5,000 ppm of calcium, and / or the cleaning agent system provides about 10 to about 800 ppm of magnesium, and / or the composition provides about 200 ppm or less of molybdenum.

11. The method according to claim 7, wherein one or more base oils of the aforementioned lubrication viscosity include base oils of API group I, base oils of API group II, or a combination thereof.

12. The method according to claim 7, wherein the composition is configured to lubricate an internal combustion engine powered by a fuel having an ignition temperature of over 800 K, or the composition is configured to lubricate an internal combustion engine powered by a fuel having an ignition temperature of over 850 K, or the fuel having an ignition temperature of over 700 K is hydrogen fuel, compressed natural gas, or liquefied natural gas, and / or the lubricating oil composition has an average measured SPI of about 6 stochastic pre-ignition (SPI) counts or less at a net mean effective pressure (BMEP) of 1000 rpm and 12 bar.

13. An internal combustion engine configured for the combustion of hydrogen fuel, An engine crankcase lubricated with a lubricating oil composition, The lubricating oil composition comprises (i) one or more base oils of lubricating viscosity, and (ii) a detergent system comprising (iiia) at least one overbasic metal-containing sulfonate detergent that provides about 2 to about 8 mmol of metal to the composition, (iiib) at least one neutral to low-basic metal-containing sulfonate detergent that provides at least about 0.02 mmol of metal to the composition, and (iic) at least one overbasic metal-containing phenate detergent that provides up to about 4 mmol of metal to the composition, wherein the lubricating oil composition has a total base number (TBN) of at least about 9.5 as measured in accordance with ASTM D2896. An internal combustion engine that uses hydrogen fuel.

14. An internal combustion engine according to claim 13, wherein the ratio of the percentage of metal provided by the overbasic metal-containing sulfonate detergent to the TBN (ASTM D2896) of the lubricating oil composition is about 0.07 or less, and / or the TBN of the lubricating oil composition is about 10 to about 15 when measured in accordance with ASTM D2896, and / or the detergent system comprises at least an overbasic metal-containing sulfonate detergent, at least an overbasic metal-containing phenate detergent, or a combination thereof, and each overbasic detergent has at least about 200 TBN (ASTM D2896).

15. The internal combustion engine according to claim 13, wherein the lubricating oil composition has a sulfated ash (SASH) content of more than 0.9 weight percent when measured in accordance with ASTM D874, or the lubricating oil composition has a sulfated ash (SASH) content of more than 1.2 weight percent when measured in accordance with ASTM D874.

16. The internal combustion engine according to claim 13, wherein the cleaning agent system provides about 1,000 to about 5,000 ppm of calcium, and / or the cleaning agent system provides about 10 to about 800 ppm of magnesium, and / or the composition further comprises one or more oil-soluble molybdenum compounds that provide about 200 ppm or less of molybdenum.

17. The internal combustion engine according to claim 13, wherein the lubricating oil composition has an average measured SPI of about 6 stochastic pre-ignition (SPI) counts or less at a net mean effective pressure (BMEP) of 1000 rpm and 12 bar.

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