Marine diesel cylinder lubricant composition

Abstract

The marine diesel engine lubricating oil composition contains (a) a large amount of lubricating viscous oil and (b) one or more olefin copolymers having a number average molecular weight of 30,000 to 120,000. The marine diesel lubricating oil composition has a TBN of less than 70 mg KOH / g. The marine diesel lubricating oil composition is a single grade lubricating oil composition that meets the 2015 January revised SAE J300 requirements for SAE40, SAE50 or SAE60 single grade lubricating oils.

Description

Technical Field

[0001] The present disclosure relates to lubricating oil compositions, and more particularly to the use of olefin copolymer thickeners in marine cylinder lubricating oil compositions.

Background Art

[0002] This section is intended to introduce the reader to various technical aspects that may be related to the various aspects of the present disclosure described and / or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. It should, therefore, be understood that these descriptions are to be interpreted in this light and should not be construed as an admission of prior art.

[0003] Marine diesel internal combustion engines can generally be classified as low-speed, medium-speed or high-speed engines. Low-speed diesel engines are unique in size and operation. These engines are extremely large and typically operate in the range of about 60 to 200 revolutions per minute (rpm). Low-speed diesel engines operate on a two-stroke cycle and are typically crosshead-type directly reversing engines in which a partition plate and one or more stuffing boxes separate the output cylinders from the crankcase to prevent combustion products from entering the crankcase and mixing with the crankcase oil. Marine two-stroke diesel cylinder lubricants must meet performance requirements in order to follow the severe operating conditions required for more modern and larger bore engines that operate at significantly varying outputs, loads and cylinder liner temperatures. Completely separating the crankcase from the combustion area has led those skilled in the art to lubricate the combustion chamber and the crankcase with different lubricating oils, known as cylinder lubricant and system oil, respectively. Marine cylinder lubricants are subject to their own requirements.

[0004] In a two-stroke crosshead type engine, the cylinders are lubricated on a gross loss basis by injecting cylinder oil individually to each cylinder by an oil injector arranged around the cylinder liner. The cylinder lubricant is not recycled and burns with the fuel. The cylinder lubricant needs to form a strong film between the cylinder liner and the piston ring to provide sufficient lubrication to the cylinder wall to prevent scuffing, and needs to be thermally stable so that the lubricant does not form deposits on the high temperature surfaces of the piston and the piston ring, and needs to be able to neutralize the sulfur-based acidic products of combustion.

[0005] Recent concerns for health and the environment have led to regulations obliging the use of lower sulfur fuels for the operation of marine diesel engines. As a result, manufacturers are now devising marine diesel engines for use with a variety of fuels, including non-residual gas fuels (e.g., compressed or liquefied natural gas), high-quality distillate fuels, and ultimately lower-quality intermediate fuels or heavy fuels, such as marine residual fuels, which generally have a higher sulfur content and a higher asphaltene content. In the case of operation with non-residual fuels, the fuel contains little asphaltene present in the fuel and has a much lower sulfur level. When burning lower sulfur fuels, less acid is formed in the combustion chamber.

[0006] One of the main characteristics of a lubricant that helps protect a marine diesel engine is the "thickness", i.e., the viscosity, of the lubricating oil film. Lubricants for lubricating marine diesel internal combustion engines have high viscosity industrial requirements due to low operating speeds and high loads, and are typically lubricants of SAE40, SAE50 or SAE60 viscosity grades, which are high viscosity single grades (i.e., those having little or no viscosity index improvement characteristics). Since hydrocracking reduces the viscosity of the base oil of the raw material, marine oils usually cannot be formulated with only hydrocracked base oils of the raw material. Conventional marine formulations typically contain a large amount of high viscosity bright stock in the marine lubricant. Bright stock is a high viscosity base oil that is highly refined and dewaxed and manufactured from raw material residual oil or bottom oil.

[0007] However, it is not always desirable to rely on bright stock. This is because there are aromatics that are oxidatively unstable. In addition, the availability of bright stock has been decreasing, and as a result, large-scale use, such as for marine engines, requires alternative solutions for imparting the desired viscosity to the lubricant. Considering the increasing severity that continues to change, associated with the design changes to modern marine engines, together with the decreasing acceptance capacity of bright stock, there continues to be a need for an improved marine diesel cylinder lubricating oil formulation technology that provides performance improvements while achieving the high viscosity required for marine cylinder lubricants. SUMMARY OF THE INVENTION

[0008] The following presents a summary of certain embodiments disclosed herein. It should be understood that these aspects are presented merely to provide a brief summary to the reader of these certain embodiments and are not intended to limit the scope of the present disclosure. Indeed, the present disclosure may encompass various aspects not shown below.

[0009] As described above, there continues to be a need for an improved marine diesel cylinder lubricating oil formulation technology that provides performance improvements while achieving the high viscosity required for marine cylinder lubricants. Now, it has been recognized that technical effects such as these can be obtained by utilizing a suitable olefin copolymer thickener in combination with a light and / or heavy neutral base oil in a marine cylinder lubricant formulation, examples of which are described herein.

[0010] As an example, in one aspect, the present disclosure relates to a marine diesel engine lubricating oil composition comprising (a) a large amount of lubricating viscous oil; and (b) one or more olefin copolymers having a number average molecular weight of 30,000 to 120,000. The marine diesel lubricating oil composition has a TBN of less than 70 mg KOH / g and is a single grade lubricating oil composition that meets the 2015 January revised SAE J300 requirements for SAE40, SAE50, or SAE60 single grade lubricants.

[0011] In another aspect, the present disclosure relates to a method of increasing the viscosity of a lubricating oil composition in a marine diesel internal combustion engine. The method includes adding to the engine a lubricating oil composition comprising (a) a large amount of lubricating viscous oil; and (b) one or more olefin copolymers having a number average molecular weight of 30,000 to 120,000. The marine diesel lubricating oil composition has a TBN of less than 70 mg KOH / g and is a single grade lubricating oil composition that meets the 2015 January revised SAE J300 requirements for SAE40, SAE50, or SAE60 single grade lubricants.

[0012] In a further aspect, the present disclosure relates to a method of suppressing deposit formation in an internal combustion engine. The method includes operating the internal combustion engine with a lubricating oil composition. The lubricating oil composition comprises (a) a large amount of lubricating viscous oil; and (b) one or more olefin copolymers having a number average molecular weight of 30,000 to 120,000. The marine diesel lubricating oil composition has a TBN of less than 70 mg KOH / g and is a single grade lubricating oil composition that meets the 2015 January revised SAE J300 requirements for SAE40, SAE50, or SAE60 single grade lubricants.

DETAILED DESCRIPTION OF THE INVENTION

[0013] Definitions As used herein, the following words and expressions have the meanings given below.

[0014] "Large amount" means more than 40 wt% of the composition.

[0015] "Small amount" means less than 40 wt% of the composition.

[0016] "Marine residual fuel" refers to a material that can be burned in large marine engines, as defined by the International Organization for Standardization (ISO) 10370, having a residual carbon of at least 2.5 wt% (e.g., at least 5 wt% or at least 8 wt%) based on the total weight of the fuel and a viscosity at 50 °C exceeding 14.0 cSt, such as the marine residual fuel defined in the International Organization for Standardization standard ISO 8217:2005 "Petroleum products - Fuels (class F) - Specifications for marine fuels", the entire contents of which are hereby incorporated by reference.

[0017] "Residual fuel" refers to a fuel that meets the specifications of residual marine fuel specified in the ISO 8217:2010 international standard. "Low-sulfur marine fuel" refers to a fuel that, in addition to meeting the specifications of residual marine fuel specified in the ISO 8217:2010 standard, has sulfur of about 1.5 wt% or less, and in some cases about 0.5 wt% or less, based on the total weight of the fuel.

[0018] "Distillate fuel" refers to a fuel that meets the specifications of distillate marine fuel specified in the ISO 8217:2010 international standard. "Low-sulfur distillate fuel" refers to a fuel that, in addition to meeting the specifications of distillate marine fuel specified in the ISO 8217:2010 international standard, has sulfur of about 0.1 wt% or less, and in some cases about 0.005 wt% or less, based on the total weight of the fuel.

[0019] "Low-sulfur fuel" means that sulfur is about 1.5 wt% or less, in some cases about 1.0 wt% or less, in some cases 0.5 wt% or less, and in some cases 0.1 wt% or less, based on the total weight of the fuel.

[0020] "High-sulfur fuel" is a fuel in which sulfur exceeds 1.5 wt% based on the total weight of the fuel.

[0021] The term "on an active substance basis" refers to an additive material that is neither a diluent oil nor a solvent.

[0022] As used in this specification and the claims, "alpha olefin" refers to an olefin having a carbon-carbon double bond between the first and second carbon atoms of the longest continuous chain of carbon atoms. The term "alpha olefin" includes linear and branched alpha olefins, unless otherwise specified. In the case of branched alpha olefins, the branch can be at the 2-position (vinylidene) and / or at positions 3 and higher with respect to the olefin double bond. The term "vinylidene" always refers to an alpha olefin having a branch at the 2-position with respect to the olefin double bond, as used in this specification and the claims. Alpha olefins are almost invariably mixtures of isomers and are often also mixtures of compounds having a certain range of carbon numbers. Low molecular weight alpha olefins, for example, C6, C8, C 10 , C 12 and C 14 alpha olefins are almost without exception 1-olefins. For higher molecular weight olefin cuts, for example, C 16 -C 18 , or C 20 -C 24 the proportion of double bonds isomerized to internal or vinylidene positions increases.

[0023] "Normal alpha olefin" (NAO) refers to a linear aliphatic monoolefin having a carbon-carbon double bond between the first and second carbon atoms. Note that "normal alpha olefin" is not synonymous with "linear alpha olefin" because the term "linear alpha olefin" can include linear olefinic compounds having a double bond between the first and second carbon atoms.

[0024] "Isomerized olefin" or "isomerized normal alpha olefin" refers to an olefin obtained by isomerizing an olefin. In general, an isomerized olefin has a double bond at a different position than the starting olefin that gave rise to it and can also have different properties.

[0025] "Isomerization level (I)" refers to the isomerization level measured by the NMR method. The isomerization level of olefins was determined by hydrogen-1 (1H) NMR. The NMR spectra were obtained at 400 MHz on a Bruker Ultrashield Plus 400 in deuterated chloroform using TopSpin 3.2 spectral processing software. The isomerization level represents the relative amount of methyl groups (-CH3) (chemical shift 0.30 - 1.01 ppm) bonded to the methylene backbone group (-CH2-) (chemical shift 1.01 - 1.38 ppm) and is defined by the equation (I) = m / (m + n), where m is the NMR integration value of the methyl group with a chemical shift of 0.30 ± 0.03 - 1.01 ± 0.03 ppm and n is the NMR integration value of the methylene group with a chemical shift of 1.01 ± 0.03 - 1.38 ± 0.10 ppm.

[0026] The terms "total base number" or "TBN" or "BN" mean the alkaline level in an oil sample according to ASTM standard D2896 or equivalent procedures, which represents the ability of the composition to continue to neutralize corrosive acids. The test measures the change in electrical conductivity and the results are expressed as mg KOH / g (the number of milligrams of KOH equivalent required to neutralize 1 gram of the product). Thus, a high TBN reflects a strongly overbased product and, as a result, a greater store of base for neutralizing acids. When a TBN value is introduced in this specification, it should be understood that it is expressed in units of mg KOH / g.

[0027] "Overbased" is used to describe a metal detergent where the ratio of the number of equivalents of the metal part to the number of equivalents of the acid part is greater than 1.

[0028] "Soap" means a neutral detergent compound containing approximately stoichiometric amounts of metal to achieve the neutralization of acidic groups or groups present in the organic acids used to make the detergent.

[0029] "Metal" refers to an alkali metal, an alkaline earth metal or a mixture thereof. When using an alkali metal, the alkali metal is lithium, sodium or potassium. When using an alkaline earth metal, the alkaline earth metal can be selected from the group consisting of calcium, barium, magnesium and strontium. Calcium and magnesium are preferred.

[0030] "Weight percent" (wt%) means, unless otherwise expressly stated, the percentage that the listed component(s), compound(s) or substituent(s) occupy in the total weight of the entire composition. All percentages reported are weight percentages on an active raw material basis (i.e., not taking into account carriers or diluent oils), unless otherwise stated. The diluent oil for lubricant additives can be any suitable base oil (e.g., Group I base oil, Group II base oil, Group III base oil, Group IV base oil, Group V base oil, or a mixture thereof). The weight percentages representing the combination of raw materials and carriers or diluent oils are called "as received" weight percentages.

[0031] The term "sulfated ash content" refers to the amount of metal-containing additives (e.g., calcium, magnesium, molybdenum, zinc) in a lubricating oil composition and is typically measured in accordance with ASTM D874, which is incorporated herein by reference.

[0032] Lubricating oil composition It has been found that by using a suitable olefin copolymer thickener in combination with a light and / or heavy neutral base oil in a marine lubricant, one or more surprising technical effects are achieved in a marine cylinder lubricant composition. These technical effects can include improved resistance to deposit formation and oxidation stability in engines operating under various load conditions, such as high load conditions, while achieving an appropriate lubricating oil viscosity.

[0033] In certain embodiments, the lubricating oil composition of the present disclosure is a marine diesel engine cylinder lubricating oil. In such embodiments, the lubricating oil composition comprises (a) a large amount of lubricating viscous oil; and (b) one or more olefin copolymers having a number average molecular weight of 30,000 to 120,000, and the lubricating oil composition is a single-grade lubricating oil composition that meets the specifications of the January 2015 revised SAE J300 requirements for SAE 40, 50, or 60 single-grade engine oils and has a TBN of less than 70 mg KOH / g as determined by ASTM D2896. The kinematic viscosity of the lubricating viscous oil may correspond to the viscosity of a heavy neutral oil or a light neutral oil.

[0034] The lubricating oil composition may be a single-grade lubricating oil composition that meets the specifications of the January 2015 revised SAE J300 requirements for 40, 50, or 60 single-grade engine oils. SAE 40 oil has a kinematic viscosity at 100 °C of 12.5 mm 2 / s to less than 16.3 mm 2 / s. SAE 50 oil has a kinematic viscosity at 100 °C of 16.3 mm 2 / s to less than 21.9 mm 2 / s. SAE 60 oil has a kinematic viscosity at 100 °C of 21.9 mm 2 / s to less than 26.1 mm 2 / s.

[0035] In some embodiments, the lubricating oil composition is suitable for use as a marine cylinder lubricant (MCL). The marine cylinder lubricant of the present disclosure is made to meet the SAE 40, SAE 50, or SAE 60 single-grade specifications to form a lubricant film with a sufficiently high viscosity on the cylinder liner wall at high temperatures.

[0036] Apart from providing a sufficient degree of lubricity, one of the main functions of a marine cylinder lubricant is to neutralize the sulfur-based acidic components of the burned sulfur-containing fuel. This neutralization has typically been accomplished by containing basic species such as overbased metal detergents. The neutralization capacity of the oil is characterized by its basicity and is measured by its total base number (TBN). Typically, sulfur-containing fuels for operating marine diesel engines create a need for marine cylinder lubricants that have high detergency and neutralization capacity even if the oil is exposed to loads such as heat for only a short period. On the other hand, low-sulfur fuels may not require as much neutralization capacity as sulfur-containing fuels.

[0037] To enable sufficient neutralization and detergency while maintaining a relatively low level of deposits, the marine diesel cylinder lubricants of the present disclosure have a TBN of less than 70 mg KOH / g. By way of example, the TBN can be in the range of less than 70 mg KOH / g to 2 mg KOH / g, or less than 70 mg KOH / g to 5 mg KOH / g, or less than 70 mg KOH / g to 10 mg KOH / g, 70 mg KOH / g to 15 mg KOH / g, 70 mg KOH / g to 20 mg KOH / g, 60 to 2 mg KOH / g, 60 to 5 mg KOH / g, 60 to 10 mg KOH / g, 60 to 15 mg KOH / g, 60 to 20 mg KOH / g, 50 to 2 mg KOH / g, 50 to 5 mg KOH / g, 50 to 10 mg 120 KOH / g, 50 to 15 mg KOH / g, or 50 to 20 mg KOH / g. As a further example, the TBN can be in the range of less than 40 mg KOH / g to 2 mg KOH / g, or less than 40 mg KOH / g to 5 mg KOH / g, or less than 40 mg KOH / g to 10 mg KOH / g, 40 mg KOH / g to 15 mg KOH / g, or 40 mg KOH / g to 20 mg KOH / g. In certain embodiments, the TBN can be in the range of 40 to 15 mg KOH / g.

[0038] In certain embodiments, the lubricating oil composition of the present disclosure has a sulfuric acid ash content of at least 1.50 wt% as determined by ASTM D874. For example, the lubricating oil composition of the present disclosure may have a sulfuric acid ash level of 1.5 - 27 wt% as determined by ASTM D874. As a further example, the lubricating oil composition of the present disclosure may have a sulfuric acid ash content of 2.0 - 25.0 wt%, 2.5 - 25.0 wt%, 3.0 - 25.0 wt%, or 5.0 - 25.0 wt% as determined by ASTM D874.

[0039] Lubricating viscous oil The lubricating oil composition of the present disclosure has at least 40 wt%, for example, at least 50 wt% (such as at least 60 wt%, at least 70 wt%, at least 80 wt%, or at least 90 wt%) of lubricating viscous oil based on the total weight of the composition. For example, the lubricating oil composition of the present disclosure may contain 40 wt% - 95 wt%, 50 wt% - 90 wt%, 55 wt% - 85 wt% of lubricating viscous oil. Lubricating viscous oil may sometimes also be referred to as base oil.

[0040] According to certain embodiments of the present disclosure, the lubricating viscous oil has a kinematic viscosity at 100 °C of 4.0 mm 2 / s to less than 8.5 mm 2 / s. For example, the lubricating viscous oil has a kinematic viscosity at 100 °C of 4.0 mm 2 / s to 8 mm 2 / s, or 4.5 mm 2 / s to 8 mm 2 / s, or 5.0 mm 2 / s to 7.5 mm 2 / s.

[0041] According to further embodiments of the present disclosure, the lubricating viscous oil has a kinematic viscosity at 100 °C of 8.5 mm 2 / s to 15.0 mm 2 / s. For example, the lubricating viscous oil has a kinematic viscosity at 100 °C of 9.0 mm 2 / s to 14.0 mm 2 / s, or 10.0 mm 2 / s to 13.0 mm 2 / s, or 10.0 mm 2 / s to 12.0 mm 2 / s can be.

[0042] In yet a further embodiment, the lubricating viscous oil may include a mixture of two or more base oils. The first base oil of the mixture of two or more base oils has a kinematic viscosity at 100 °C of 8.5 mm 2 / s to 15.0 mm 2 / s, for example, 4.0 mm 2 / s to 8 mm 2 / s, or 4.5 mm 2 / s to 8 mm 2 / s, or 5.0 mm 2 / s to 7.5 mm 2 / s. The second base oil of the mixture of two or more base oils has a kinematic viscosity at 100 °C of 8.5 mm 2 / s to 15.0 mm 2 / s, for example, 9.0 mm 2 / s to 14.0 mm 2 / s, or 10.0 mm 2 / s to 13.0 mm 2 / s, or 10.0 mm 2 / s to 12.0 mm 2 / s can be.

[0043] The lubricating viscous oil of the present disclosure may include only one base oil component or a mixture of two or more base oil components to provide the above kinematic viscosity. The lubricating viscous oil may be selected from any of Groups I to V of base oils specified in the American Petroleum Institute (API) base oil interchangeability regulations (API 1509). The five base oil groups are summarized in Table 1 below.

Table 1

[0044] Groups I - III are mineral oil process feedstocks. Group IV base oils contain true synthetic molecular species produced by the polymerization of olefinically unsaturated hydrocarbons. Many Group V base oils are also true synthetic products and can include diesters, polyol esters, polyalkylene glycols, alkylated aromatics, polyphosphate esters, polyvinyl ethers, and / or polyphenyl ethers, but can also be naturally occurring oils such as vegetable oils. Despite Group III base oils being derived from mineral oils, it should be noted that the severe processing these fluids undergo causes their physical properties to closely resemble those of some true synthetic oils such as PAO. Therefore, oils derived from Group III base oils are sometimes referred to in the industry as synthetic fluids.

[0045] The base oils used in the disclosed lubricating oil compositions can be mineral oils, animal oils, vegetable oils, synthetic oils, or mixtures thereof. Suitable oils can be derived from hydrocracked, hydrogenated, hydrofinished, unrefined, refined, and re-refined oils, and mixtures thereof.

[0046] Unrefined oils are those derived from natural, inorganic, or synthetic sources without, or with very little, further refining treatment. Refined oils are similar to unrefined oils except that they have been treated in one or more refining processes that can result in the improvement of one or more properties. Examples of suitable refining techniques are solvent extraction, secondary distillation, acid or base extraction, filtration, leaching, etc. Oils refined to food grade quality may or may not be useful. Edible oils are sometimes also referred to as white oils. In some embodiments, the lubricating oil composition does not contain edible oil or white oil.

[0047] Re-refined oils are also known as recycled or reprocessed oils. These oils are obtained using the same or similar processes as refined oils. In many cases, these oils are further treated by techniques aimed at removing used additives and oil degradation products.

[0048] Mineral oils can include those obtained by excavation, or oils derived from plants and animals, or any mixture thereof. Such oils include castor oil, lard oil, olive oil, peanut oil, corn oil, soybean oil, and linseed oil, as well as inorganic lubricating oils such as liquid petroleum oils, and paraffinic, naphthenic, or solvent-treated or acid-treated inorganic lubricating oils of a mixed paraffinic and naphthenic type. Such oils may be partially or fully hydrogenated if desired. Oils derived from coal or shale are also useful.

[0049] Useful synthetic lubricating oils include hydrocarbon oils such as polymerized, oligomerized, or copolymerized olefins (e.g., polybutylene, polypropylene, propylene / isobutylene copolymer); poly(1-hexene), poly(1-octene), trimers of 1-decene such as poly(1-decene), such materials being often referred to as α-olefins, and furthermore, mixtures thereof, alkylbenzenes (e.g., dodecylbenzene, tetradecylbenzene, dinonylbenzene, di-(2-ethylhexyl)benzene); polyphenyls (e.g., biphenyl, terphenyl, alkylated polyphenyls); diphenylalkanes, alkylated diphenylalkanes, alkylated diphenyl ethers and alkylated diphenyl sulfides, and derivatives, analogs and homologs thereof, or mixtures thereof. Polyalphaolefins are typically hydrogenated materials.

[0050] Other synthetic lubricating oils include polyol esters, diesters, liquid esters of phosphorus-containing acids (e.g., tricresyl phosphate, trioctyl phosphate, and diethyl ester of decanephosphonic acid), or high molecular weight tetrahydrofuran. Synthetic oils can be produced by the Fischer-Tropsch reaction and can typically be hydrogen isomerized Fischer-Tropsch hydrocarbons or waxes. In one embodiment, the oil can be prepared by Fischer-Tropsch gas-liquid synthesis procedures similar to other gas-liquid oils.

[0051] The base oils useful for formulating lubricating oils in the present disclosure are any of the various oils corresponding to API Group I, Group II, Group III, Group IV, and Group V oils, as well as mixtures thereof. In one embodiment, the base oil is a Group II base oil or a blend of two or more different base oils. In another embodiment, the base oil is a Group I base oil or a blend of two or more different Group I base oils. Suitable Group I base oils include light overhead fractions from vacuum distillation columns, such as any light neutral, medium neutral, and heavy neutral feedstock base oils, etc.

[0052] The base oil may also include a feedstock residue base oil or bottom fraction, such as bright stock. Bright stock is a high-viscosity base oil conventionally produced from feedstock residue oil or bottom oil and is highly refined and dewaxed. Bright stock has a kinematic viscosity at 40 °C greater than 180 mm 2 / s (e.g., greater than 250 mm 2 / s, and in some cases in the range of 500 - 1100 mm 2 / s). In certain embodiments, the lubricating oil composition does not contain bright stock.

[0053] Viscosity modifier According to this embodiment, a viscosity modifier can be added to the lubricating oil composition to increase its viscosity in order to obtain a finished lubricating oil composition having a desired viscosity grade. Surprisingly, when using a suitable olefin copolymer viscosity modifier in combination with light and / or heavy neutral base oils, it has been found that a lubricating oil composition is provided that exhibits improved resistance to deposit formation and oxidation stability in engines operating under high load conditions while achieving an appropriate lubricating oil viscosity.

[0054] According to embodiments of the present disclosure, suitable thickeners may include olefin copolymers (OCPs) as described herein. Such additives will generally be present at 0.1 wt% or more, for example, 0.1 - 12 wt% of the lubricating oil composition based on the active substance. In certain embodiments, the OCP is present at 0.2 - 10 wt%, 0.3 - 9 wt%, 0.4 - 8 wt%, or 0.5 - 7 wt% of the lubricating oil composition based on the active substance. In yet further embodiments, the OCP is present at 0.5 - 12.0 wt%, 0.5 - 5 wt%, or 1 - 2 wt% of the lubricating oil composition based on the active substance. In further embodiments, the OCP is present at 1.0 wt% or more, for example, 1.0 - 12.0 wt%, 1.0 wt% - 5 wt%, 1.3 wt% - 4.5 wt%, 1.5 wt% - 4.0 wt%, 2.0 - 12.0 wt%, or 2.0 wt% - 3.5 wt% of the lubricating oil composition based on the active substance. In certain embodiments, the OCP is the only viscosity modifier or thickener present in the lubricating oil composition.

[0055] In certain embodiments, the olefin copolymer is a copolymer based on ethylene units and units of alpha olefins (e.g., normal alpha olefins, isomerized alpha olefins), such as an ethylene - propylene copolymer composition. Suitable other alpha olefins that may substitute for propylene or be combined with ethylene and propylene to form a terpolymer or a quaternary polymer include, for example, 1 - butene, 1 - pentene, 1 - hexene, 1 - heptene, 1 - octene, 1 - nonene, 1 - decene, and branched - chain alpha olefins such as 4 - methyl - 1 - pentene, 4 - methyl - 1 - hexene, 4 - methylpentene - 1,4,4 - dimethyl - 1 - pentene, 6 - methylheptene - 1, and mixtures thereof.

[0056] The olefin copolymer according to a particular embodiment of the present invention advantageously has a number average molecular weight of from 30,000 to 120,000 g / mol, preferably from 40,000 to 120,000 g / mol, more preferably from 45,000 to 115,000 g / mol. In some embodiments, such molecular weight can balance useful thickening and the stability of the formulation under load. The molecular weight, in combination with the amounts referenced above, can provide an appropriate viscosity for a marine cylinder lubricant composition.

[0057] The shear stability index (SSI) of the olefin copolymer, i.e., its resistance to mechanical degradation under shear stress, is in the range of 5 to 50. In certain embodiments, the SSI is in the range of 15 to 50, for example, 24 to 50, or 24 to 40.

[0058] The olefin copolymer according to a particular embodiment of the present invention advantageously has an ethylene unit content in the range of 30% to 80% by weight, preferably 30% to 75% by weight, more preferably 49% to 72% by weight, based on the weight of the olefin copolymer. The olefin copolymer according to the present invention also advantageously has an ethylene unit content in the range of 40% to 90 mol%, preferably 40% to 80%, more preferably 50% to 80% on a molar basis, based on the number of moles of the olefin copolymer.

[0059] The olefin copolymer according to a particular embodiment of the present invention can be a bimodal ethylene copolymer composition having a first ethylene copolymer portion having a relatively low ethylene content and a second ethylene copolymer portion having a relatively high ethylene content. In one embodiment, the polymerization process used to produce the olefin copolymer is in the presence of one or more metallocene catalysts with two or more alpha-olefin monomers, one of which is preferably ethylene and the remainder are, in some embodiments, C3 - C 12It may include copolymerizing an alpha-olefin, which may be, for example, propylene. The olefin copolymer used in certain embodiments may include one or more olefin copolymers described in US20130203640, the entire disclosure of which is hereby incorporated by reference.

[0060] In certain ones of these embodiments, the olefin copolymer composition of the present disclosure may include (a) a first ethylene-alpha olefin copolymer and (b) a second ethylene-alpha olefin copolymer. As an example, the first ethylene-alpha olefin copolymer (a) has an ethylene content of about 60 to about 80 wt%, and may be referred to herein as a "semicrystalline" ethylene-alpha olefin copolymer. More typically, the ethylene content of the first ethylene-alpha olefin copolymer is about 63 to about 77 wt%, and even more typically, the ethylene content of the first ethylene-alpha olefin copolymer is about 65 to about 75 wt%. The second ethylene-alpha olefin copolymer (b) has an ethylene content of less than about 60 wt%, more typically less than about 55 wt%, and even more typically about 42 to about 54 wt%, and is a less crystalline ethylene-alpha olefin copolymer than the first ethylene-alpha olefin copolymer (a), and may be referred to herein as an "amorphous" ethylene-alpha olefin copolymer.

[0061] The first ethylene - alpha - olefin copolymer (a) has a melt flow rate ratio (MFRR), as defined as the ratio of the MFR measured at 230°C / 21.6 kg and 230°C / 2.16 kg, greater than 30, more typically up to about 55, even more typically from about 33 to about 45, preferably greater than 34, more preferably from about 34 to about 45, and even more preferably from about 35 to about 43. The first ethylene - alpha - olefin copolymer (a) has an MFR of at least about 1.5 g / 10 min when the MFR conditions are also observed, and in another embodiment, the MFR is at least about 1.6 g / 10 min. A more typical range of the MFR is from about 1.5 g / 10 min to about 6.5 g / 10 min, and an even more typical range is from about 2.5 g / 10 min to about 5.5 g / 10 min. The MFR is measured by condition L (230°C / 2.16 kg) of ASTM D1238. In one embodiment, the first ethylene - alpha - olefin copolymer (a) has an MFRR greater than 30 and an MFR of at least about 1.5 g / 10 min. More preferably, the first ethylene - alpha - olefin copolymer (a) has an MFRR greater than 34 and an MFR of at least about 1.6 g / 10 min.

[0062] In one embodiment, the olefin copolymer composition contains from about 30 wt% to about 70 wt% of the first ethylene - alpha - olefin copolymer (a) and from about 70 wt% to about 30 wt% of the second ethylene - alpha - olefin copolymer (b), based on the total amount of (a) and (b) in the composition. In another embodiment, the olefin copolymer composition contains from about 40 wt% to about 60 wt% of the first ethylene - alpha - olefin copolymer (a) and from about 60 wt% to about 40 wt% of the second ethylene - alpha - olefin copolymer (b), based on the total amount of (a) and (b) in the composition. In a particular embodiment, the olefin copolymer composition contains from about 50 to about 54 wt% of the first ethylene - alpha - olefin copolymer (a) and from about 46 to about 50 wt% of the second ethylene - alpha - olefin copolymer (b), based on the total amount of (a) and (b) in the composition.

[0063] In one embodiment, the weight average molecular weight of the first ethylene-alpha olefin copolymer is from about 60,000 to about 120,000. In another embodiment, the weight average molecular weight of the first ethylene-alpha olefin copolymer is from about 70,000 to about 110,000. In one embodiment, the weight average molecular weight of the second ethylene-alpha olefin copolymer is from about 60,000 to about 120,000. In another embodiment, the weight average molecular weight of the second ethylene-alpha olefin copolymer is from about 70,000 to about 110,000.

[0064] In one embodiment, the weight average molecular weight of the composition of the first ethylene-alpha olefin copolymer and the second ethylene-alpha olefin copolymer is from about 60,000 to about 120,000. In another embodiment, the weight average molecular weight of the composition of the first ethylene-alpha olefin copolymer and the second ethylene-alpha olefin copolymer is from about 70,000 to about 110,000. In yet a further embodiment, the weight average molecular weight of the composition of the first ethylene-alpha olefin copolymer and the second ethylene-alpha olefin copolymer is from about 80,000 to about 100,000. The molecular weight distribution of each of the ethylene-alpha olefin copolymers can be less than about 2.5, more typically from about 2.1 to about 2.4. The polymer distribution as determined by GPC for each of the ethylene-alpha olefin copolymers is typically unimodal.

[0065] Other performance additives The lubricant composition of the present disclosure may contain one or more performance additives that can impart or improve any desirable properties of the lubricant composition. Any additive known to those skilled in the art can be used in the lubricant composition disclosed herein. Descriptions of some suitable additives are made by R.M. Mortier et al. “Chemistry and Technology of Lubricants,” 3rd Edition, Springer (2010), and L.R. Rudnik “Lubricant Additives: Chemistry and Applications,” Second Edition, CRC Press (2009).

[0066] Generally, the concentration of each additive in the lubricant composition when used can be in the range of 0.001 to 10 wt% (e.g., 0.01 to 5 wt%, or 0.05 to 2.5 wt%) of the lubricant composition. Each additive in the lubricant composition, including diluent oil, can be in the range of 0.5 to 45 wt% (e.g., 1.0 to 45 wt%, 5.0 to 40 wt%, 10 to 35 wt%, 20 to 32 wt%, or 25 to 30 wt%) of the lubricant composition. Further, the total amount of additives in the lubricant composition can be in the range of 0.001 to 20 wt% (e.g., 0.01 to 15 wt%, or 0.1 to 10 wt%) of the lubricant composition. The total amount of additives in the lubricant composition, including diluent oil, can be in the range of 0.5 to 78 wt% (e.g., 1.0 to 78 wt%, 5.0 to 78 wt%, 10 to 78 wt%, 20 to 78 wt%, 30 to 78 wt%, or 45 to 78 wt%) of the lubricant composition.

[0067] By way of example, the present lubricant composition may contain one or more lubricant performance additives including detergents, dispersants, anti-wear agents, antioxidants, friction modifiers, corrosion inhibitors, rust inhibitors, demulsifiers, antifoaming agents, viscosity modifiers, pour point depressants, nonionic surfactants, thickeners, and the like. Some of these are described in more detail below.

[0068] Detergent The lubricating oil composition of the present disclosure may include one or more detergents. A detergent is an additive that reduces the formation of piston deposits, such as high-temperature varnish and lacquer deposits, in an engine. Detergents typically have acid-neutralizing properties and can keep fine solid particles in suspension. Most detergents are metal salts of acidic organic compounds.

[0069] Detergents containing metals or forming ash function as detergents for reducing or removing deposits, as well as acid neutralizers or rust inhibitors, thereby reducing wear and corrosion and extending the life of the engine. Detergents generally include a polar head having a long hydrophobic tail. The polar head includes a metal salt of an acidic organic compound.

[0070] In the art, detergents are generally considered to be neutral or overbased. A detergent containing substantially stoichiometric amounts of metal salts is usually referred to as a standard or neutral detergent. In embodiments where a large amount of metal base is incorporated into the detergent by reacting an excess metal compound (e.g., an oxide or hydroxide) with an acidic gas (e.g., carbon dioxide), the detergent is considered overbased.

[0071] Overbased metal detergents are generally produced by carbonating (with CO2) a mixture of a hydrocarbon, a detergent acid (e.g., a sulfonic acid or a carboxylic acid), a metal oxide or hydroxide (e.g., calcium oxide or calcium hydroxide), and an accelerator, such as xylene, methanol, and / or water. For example, to prepare overbased calcium sulfonate in carbonation, calcium oxide or calcium hydroxide reacts with gaseous carbon dioxide to form calcium carbonate. The sulfonic acid is neutralized with excess CaO or Ca(OH)2 to form a sulfonate.

[0072] Overbased detergents can be further characterized as low overbased, medium overbased or high overbased. A low overbased detergent can be, for example, an overbased salt having a TBN of less than 100. In one embodiment, the TBN of the low overbased salt can be from about 5 to about 80. In another embodiment, the TBN of the low overbased salt can be from about 10 to about 80. In yet another embodiment, the TBN of the low overbased salt can be from about 10 to about 50.

[0073] A medium overbased detergent can be, for example, an overbased salt having a TBN of from about 100 to about 250. In one embodiment, the TBN of the medium overbased salt can be from about 100 to about 200. In another embodiment, the TBN of the medium overbased salt can be from about 125 to about 175.

[0074] A high overbased detergent can be, for example, an overbased salt having a TBN of greater than 250. In one embodiment, the TBN of the high overbased salt can be from about 250 to about 800.

[0075] Compounds that can be used as detergents include oil-soluble neutral and overbased sulfonates, phenates, sulfurized phenates, thiophosphonates, salicylates and naphthenates of metals, especially alkali or alkaline earth metals such as barium, sodium, potassium, lithium, calcium and magnesium, and other oil-soluble carboxylates. The most commonly used metals are calcium and magnesium, which may both be present in the detergents used in lubricants, and mixtures of calcium and / or magnesium with sodium.

[0076] In one embodiment, the detergent can be one or more alkali or alkaline earth metal salts of alkyl-substituted hydroxyaromatic carboxylic acids and is a carboxylate or salicylate. Suitable hydroxyaromatic compounds include mononuclear mono-hydroxy and poly-hydroxy aromatic hydrocarbons having from 1 to 4, preferably from 1 to 3, hydroxyl groups.

[0077] Suitable hydroxyaromatic compounds include phenol, catechol, resorcinol, hydroquinone, pyrogallol, cresol, and the like. In certain embodiments, a preferred hydroxyaromatic compound is phenol.

[0078] The alkyl substitution part of an alkali or alkaline earth metal salt of an alkyl-substituted hydroxyaromatic carboxylic acid can be derived from an alpha olefin having 10 to 80 carbon atoms. The olefin used can be linear, isomerized linear, branched, or partially branched linear. The olefin can be a mixture of linear olefins, a mixture of isomerized linear olefins, a mixture of branched olefins, a mixture of partially branched linear olefins, or a mixture of any of the above.

[0079] In some embodiments, the mixture of linear olefins is a mixture of normal alpha olefins selected from olefins having 10 to 40 carbon atoms per molecule. In one embodiment, the normal alpha olefin is isomerized using at least one of a solid catalyst or a liquid catalyst.

[0080] In some embodiments, among the alkyl groups contained in an alkali or alkaline earth metal salt of an alkyl-substituted hydroxyaromatic carboxylic acid, for example, among the alkyl groups of an alkaline earth metal salt of an alkyl-substituted hydroxybenzoic acid detergent, at least about 75 mol% (e.g., at least about 80 mol%, at least about 85 mol%, at least about 90 mol%, at least about 95 mol%, or at least about 99 mol%) are C 20 alkyl substituents as described above. In certain of these embodiments, the alkali or alkaline earth metal salt of the alkyl-substituted hydroxyaromatic carboxylic acid has at least 75 mol% of C 20 ~C 28An alkali or alkaline earth metal salt of an alkyl-substituted hydroxybenzoic acid, which is derived from an alkyl-substituted hydroxybenzoic acid having a residue of a normal alpha olefin containing a normal alpha olefin as an alkyl group. In another embodiment, at least about 50 mol% (e.g., at least 60 mol%, at least 70 mol%, at least 80 mol%, at least 85 mol%, at least 90 mol%, at least 95 mol%, or at least 99 mol%) of the alkyl groups of the alkali or alkaline earth metal salt of the alkyl-substituted hydroxybenzoic acid is C 20 ~C 24 an alkyl substituent.

[0081] In another embodiment, at least about 50 mol% (e.g., at least 60 mol%, at least 70 mol%, at least 80 mol%, at least 85 mol%, at least 90 mol%, at least 95 mol%, or at least 99 mol%) of the alkyl groups of the alkali or alkaline earth metal salt of the alkyl-substituted hydroxybenzoic acid is C 14 ~C 18 an alkyl substituent. In another embodiment, the alkali or alkaline earth metal salt of the alkyl-substituted hydroxyaromatic carboxylic acid is isomerized C 10 ~C 40 normal alpha olefin, isomerized C 20 ~C 28 normal alpha olefin, or preferably isomerized C 20 ~C 24 normal alpha olefin having an alkyl group derived from. In one embodiment, the isomerized normal alpha olefin has an isomerization level of the alpha olefin of about 0.1 to about 0.4. In another embodiment, the alkyl group is derived from at least two alkylphenols. The alkyl group attached to at least one of the at least two alkylphenols is derived from an isomerized alpha olefin. The alkyl group attached to the other alkylphenol may be derived from a branched or partially branched olefin, a highly isomerized olefin, or a mixture thereof.

[0082] For the alkali or alkaline earth metal salts of alkyl-substituted hydroxyaromatic carboxylic acids, the alkyl-substituted moiety may be derived from cashew nut shell liquid (CNSL) or hydrodistilled CNSL. Distilled CNSL is a mixture of biodegradable meta-hydrocarbyl-substituted phenols including cardanol, which has a linear and unsaturated hydrocarbyl group. The catalytic hydrogenation of distilled CNSL yields a mixture of meta-hydrocarbyl-substituted phenols rich mainly in 3-pentadecylphenol.

[0083] The alkali or alkaline earth metal salts of alkyl-substituted hydroxyaromatic carboxylic acids can be a mixture of ortho and para isomers. In one embodiment, the alkyl-substituted hydroxyaromatic carboxylic acid can contain 1 to 99% ortho isomer and 99 to 1% para isomer. In another embodiment, the alkyl-substituted hydroxyaromatic carboxylic acid can contain about 5 to 70% ortho isomer and 95 to 30% para isomer.

[0084] The alkali or alkaline earth metal salts of alkyl-substituted hydroxyaromatic carboxylic acids can be neutral or overbased. Generally, the overbased alkali or alkaline earth metal salts of alkyl-substituted hydroxyaromatic carboxylic acids have an improved TBN of the alkali or alkaline earth metal salts of alkyl-substituted hydroxyaromatic carboxylic acids by processes such as adding a base source (e.g., lime) and an acid compound for overbasing (e.g., carbon dioxide).

[0085] As described above, certain embodiments of the lubricating oil formulation may use one or more sulfonate detergents alone or in combination with other detergents. The sulfonates can be prepared from sulfonic acids obtainable by sulfonating alkyl-substituted aromatic hydrocarbons such as those obtained by fractional distillation of petroleum or alkylation of aromatic hydrocarbons. Examples of alkyl-substituted aromatic hydrocarbons that can be sulfonated include those obtained by alkylating benzene, toluene, xylene, naphthalene, diphenyl or halogen derivatives thereof. The alkylation can be carried out in the presence of a catalyst and an alkylating agent having from 3 to more than 70 carbon atoms. Alkaryl sulfonates usually contain from 9 to more than 80 carbon atoms, preferably from 16 to 60, preferably from 16 to 30, and most preferably from 20 to 24 carbon atoms per alkyl-substituted aromatic moiety.

[0086] The oil-soluble sulfonates or alkaryl sulfonic acids can be neutralized with metal oxides, hydroxides, alkoxides, carbonates, carboxylates, sulfides, hydrosulfides, nitrates, borates and ethers. The amount of the metal compound is selected taking into account the desired TBN of the final product.

[0087] Metal salts of phenols and sulfurized phenols (e.g., phenate or sulfurized phenate detergents) are prepared by reacting phenol or sulfurized phenol with a suitable metal compound such as an oxide or hydroxide. Sulfurized phenol can be prepared by reacting phenol with sulfur or a sulfur-containing compound such as hydrogen sulfide, sulfur monohalide or sulfur dihalide to form a product that is usually a mixture of compounds in which two or more phenols are bridged by sulfur-containing bridges. Further details regarding the general preparation of sulfurized phenates can be found, for example, in U.S. Pat. Nos. 2,680,096, 3,178,368 and 3,801,507, the contents of which are incorporated herein by reference.

[0088] The sulfur used for the formation of the sulfurized compound can have any allotropic form of sulfur. Sulfur can exist either as molten sulfur, or as a solid (e.g., powder or fine particles), or as a suspension of a solid in a compatible hydrocarbon liquid.

[0089] In some embodiments, it is desirable to use calcium hydroxide as the calcium base because it is easier to handle, for example, compared to calcium oxide, and yet gives excellent results. Other calcium bases, such as calcium alkoxides, may also be used.

[0090] Suitable alkylphenols that can be used are those in which the alkyl substituents contain a sufficient number of carbon atoms so as to render the resulting alkylphenate (e.g., overbased calcium sulfonate alkylphenate) composition oil-soluble. Oil solubility can be provided by a single long-chain alkyl substituent or by a combination of alkyl substituents. Typically, the alkylphenols used will be a mixture of different alkylphenols, e.g., C 20 ~C 24 alkylphenol mixture. In one embodiment, a suitable alkylphenol compound will be derived from an isomerized normal alpha olefin alkyl group having from about 10 to about 40 carbon atoms per molecule and an isomerization level of the alpha olefin of from about 0.1 to about 0.4. In one embodiment, the isomerized normal alpha olefin has from about 20 to about 24 carbon atoms. In one embodiment, a suitable alkylphenol compound will be derived from an alkyl group that is a branched olefinic propylene oligomer or a mixture thereof having from about 9 to about 80 carbon atoms. In one embodiment, the branched olefinic propylene oligomer or mixture thereof has from about 9 to about 40 carbon atoms. In one embodiment, the branched olefinic propylene oligomer or mixture thereof has from about 9 to about 18 carbon atoms. In one embodiment, the branched olefinic propylene oligomer or mixture thereof has from about 9 to about 12 carbon atoms.

[0091] In one embodiment, suitable alkylphenolic compounds include distilled cashew nut shell liquid (CNSL) or hydrogenated distilled CNSL. Distilled CNSL is a mixture of biodegradable meta-hydrocarbyl-substituted phenols including cardanol, having a hydrocarbyl group that is linear and unsaturated. Contact hydrogenation of distilled CNSL results in a mixture of meta-hydrocarbyl-substituted phenols that is rich in 3-pentadecylphenol.

[0092] The alkylphenol can be para-alkylphenol, meta-alkylphenol or ortho-alkylphenol. In certain embodiments where overbased products are desired, the alkylphenol preferably consists predominantly of para-alkylphenol, with no more than about 45 mole percent of the alkylphenol being ortho-alkylphenol; more preferably, no more than about 35 mole percent of the alkylphenol is ortho-alkylphenol. Alkyl-hydroxy toluene or xylene, and other alkylphenols having one or more alkyl substituents in addition to at least one long-chain alkyl substituent can also be used. In the case of distilled cashew nut shell liquid, contact hydrogenation of distilled CNSL results in a mixture of meta-hydrocarbyl-substituted phenols.

[0093] Generally, the selection of the alkylphenol can be based on the properties desired in the marine diesel engine lubricating oil composition, particularly TBN and oil solubility. Further information regarding the preparation of suitable alkylphenols can be found, for example, in U.S. Pat. Nos. 5,024,773, 5,320,763, 5,318,710 and 5,320,762, each of which is incorporated herein by reference.

[0094] Typically, the amount of the detergent can be from about 0.001 wt% to about 50 wt%, or from about 0.05 wt% to about 25 wt%, or from about 0.1 wt% to about 20 wt%, or from about 0.01 to 15 wt%, based on the total weight of the marine diesel lubricating oil composition.

[0095] The detergent may also include a mixed surfactant system containing a phenate and / or sulfonate component, such as those described in U.S. Patent Nos. 6,429,178, 6,429,179, and 6,153,565, for example, "hybrid" or "composite" detergents formed by phenate / salicylate, sulfonate / phenate, sulfonate / salicylate, sulfonate / phenate / salicylate. The detergent may also include a methylene-bridged polyphenol composition prepared by reacting phenol with formaldehyde or its reversible polymer, optionally sulfiding the methylene-bridged intermediate and then reacting the intermediate with an excess of metal base to produce a methylene-bridged polyphenol phenate composition. In one embodiment, the methylene-bridged polyphenol phenate composition may be further reacted with an epoxide. In one embodiment, the methylene-bridged polyphenol phenate composition is not sulfided.

[0096] Other detergents may be present in any suitable amount, for example, from 0.1 to 45 wt% or from 0.5 to 30 wt% of the lubricating oil composition.

[0097] Dispersant The lubricating oil composition of the present disclosure may include one or more dispersants. Oil-insoluble oxidation by-products are generated during the operation of the engine. The dispersant helps to keep these by-products in a dissolved state and thus reduces their deposition on the metal surface. The dispersant does not contain ash-forming metals before being incorporated into the lubricating oil composition and is often known as an ashless dispersant because it generally does not cause any ash when added to the lubricant. Ashless dispersants are characterized by polar groups bonded to relatively high molecular weight hydrocarbon chains. Typical ashless dispersants include N-substituted long-chain alkenyl succinimides. Examples of N-substituted long-chain alkenyl succinimides include polyisobutylene succinimides in which the number average molecular weight of the polyisobutylene substituent ranges from 500 to 5000 daltons (e.g., 900 to 2500 daltons). The succinimide dispersant and its preparation are disclosed, for example, in U.S. Patent Nos. 4,234,435 and 7,897,696. The succinimide dispersant is typically an imide formed from a polyamine, typically poly(ethyleneamine).

[0098] In some embodiments, the lubricant composition includes at least one polyisobutylene succinimide dispersant derived from polyisobutylene having a number average molecular weight in the range of 500 to 5000 daltons (e.g., 900 to 2500 daltons). The polyisobutylene succinimide can be used alone or in combination with other dispersants.

[0099] The dispersant may be post-treated by reaction with any of various agents by conventional methods. These agents include boron compounds (e.g., boric acid), and cyclic carbonates (e.g., ethylene carbonate).

[0100] Another class of dispersants includes Mannich bases. Mannich bases are materials formed by condensing higher molecular weight alkyl-substituted phenols, polyalkylene polyamines, and aldehydes, such as formaldehyde. Mannich bases are described in more detail in U.S. Patent No. 3,634,515.

[0101] Another class of dispersants includes high molecular weight esters prepared by the reaction of a hydrocarbyl acylating agent with a polyhydroxy aliphatic alcohol such as glycerol, pentaerythritol or sorbitol. Such materials are described in more detail in U.S. Patent No. 3,381,022.

[0102] Another class of dispersants includes high molecular weight ester amides.

[0103] The dispersant may be present in the lubricating oil composition in an amount of 0.1 to 15 wt%.

[0104] Antiwear agent Antiwear agents reduce friction and excessive wear and typically comprise compounds containing sulfur or phosphorus or both as the main component. Of particular note are metal dihydrocarbyl dithiophosphates where the metal can be an alkali or alkaline earth metal or aluminum, lead, tin, molybdenum, manganese, nickel, copper or zinc. Zinc dihydrocarbyl dithiophosphate (ZDDP) is an oil-soluble salt of dihydrocarbyl dithiophosphoric acid and has the following formula: Zn[SP(S)(OR)(OR’)]2 wherein R and R′ can be the same or different hydrocarbyl radicals containing from 1 to 18 (e.g., 2 to 12) carbon atoms and can be represented by. To obtain oil solubility, the total number of carbon atoms in the dithiophosphoric acid (i.e., R and R′) is generally 5 or more.

[0105] The antiwear agent may be present in the lubricating oil composition in an amount of 0.1 to 6 wt%.

[0106] Antioxidant Antioxidants retard the oxidative degradation of the base oil during use. Such degradation can lead to deposits on metal surfaces, the presence of sludge, or an increase in viscosity in the lubricant.

[0107] Useful antioxidants include hindered phenols. Hindered phenol antioxidants often contain a secondary butyl group and / or a tertiary butyl group as the steric hindrance group. The phenol group may further be substituted with a hydrocarbyl group (typically a linear or branched alkyl), and / or a crosslinking group linking to a second aromatic group. Examples of hindered phenol antioxidants include 2,6-di-tert-butylphenol, 2,6-di-tert-butylcresol, 2,4,6-tri-tert-butylphenol, 2,6-dialkyl-phenolic propionate derivatives, and bisphenols, for example, 4,4'-bis(2,6-di-tert-butylphenol) and 4,4'-methylene-bis(2,6-di-tert-butylphenol).

[0108] Alkylphenol sulfides, as well as their alkali and alkaline earth metal salts, are also useful as antioxidants.

[0109] Non-phenolic antioxidants that can be used may include aromatic amine antioxidants, for example, diarylamines and alkylated diarylamines. Specific examples of aromatic amine antioxidants include N-phenyl-2-naphthylamine, 4,4'-dioctyldiphenylamine, butylated / octylated diphenylamine, nonylated diphenylamine, and octylated N-phenyl-2-naphthylamine.

[0110] The antioxidant may be present in the lubricating oil composition at 0.01 to 15.0 wt%.

[0111] Friction modifier A friction modifier is any material that can change the coefficient of friction of a surface coated with any lubricant or fluid containing such a material. Suitable friction modifiers include fatty amines, esters such as glycerol borate esters, fatty phosphites, fatty acid amides, fatty epoxides, borated fatty epoxides, alkoxylated fatty amines, borated alkoxylated fatty amines, metal salts of fatty acids, or fatty imidazolines, as well as condensation products of carboxylic acids and polyalkylene-polyamines. As used herein, the term "fatty" with respect to a friction modifier means a carbon chain having 10 to 22 carbon atoms, typically a straight-chain carbon chain. Molybdenum compounds are also known as friction modifiers. The friction modifier can be present in the lubricating oil composition at 0.01 to 10.0 wt%.

[0112] Rust inhibitor Rust inhibitors generally protect lubricated metal surfaces from chemical attack by water or other contaminants. Suitable rust inhibitors can include nonionic suitable rust inhibitors, which include polyoxyalkylene agents (e.g., polyoxyethylene lauryl ether, polyoxyethylene higher alcohol ether, polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene octyl stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene sorbitol monostearate, polyoxyethylene sorbitol monooleate, and polyethylene glycol monooleate); stearic acid and other fatty acids; dicarboxylic acids; metal soaps; fatty acid amine salts; metal salts of heavy sulfonic acids; partial carboxylic acid esters of polyhydric alcohols; phosphate esters; (short-chain) alkenyl succinic acids, their partial esters and their nitrogen-containing derivatives; and synthetic alkylaryl sulfonates (e.g., metal salts of dinonylnaphthalene sulfonic acid). Such additives can be present in the lubricating oil composition at 0.01 to 5 wt%.

[0113] Demulsifier The demulsifier promotes oil-water separation in a lubricating oil composition exposed to water or steam. Suitable demulsifiers include trialkyl phosphates, as well as various polymers and copolymers of ethylene glycol, ethylene oxide, propylene oxide, or mixtures thereof. Such additives can be present at 0.01 - 5 wt% of the lubricating oil composition.

[0114] Antifoaming agent The antifoaming agent delays the formation of stable bubbles. Silicones and organic polymers are typical antifoaming agents. For example, polysiloxanes such as silicone oil or polydimethylsiloxane provide antifoaming properties. Further antifoaming agents include copolymers of ethyl acrylate and 2-ethylhexyl acrylate, optionally with vinyl acetate. Such additives can be present at 0.001 - 1 wt% of the lubricating oil composition.

[0115] Viscosity modifier The viscosity modifier results in a lubricant having operability at high and low temperatures. These additives impart shear stability at elevated temperatures and an acceptable viscosity at low temperatures. Suitable viscosity modifiers can include polyolefins, olefin copolymers (OCP), ethylene / propylene copolymers, polyisobutene, hydrogenated styrene-isoprene polymers, styrene / maleic ester copolymers, hydrogenated styrene / butadiene copolymers, hydrogenated isoprene polymers, alpha-olefin maleic anhydride copolymers, polymethacrylates, polyacrylates, polyalkylstyrenes, and hydrogenated alkenylaryl conjugated diene copolymers. Such additives can be present at 0.1 - 15 wt% of the lubricating oil composition.

[0116] Pour point depressant The pour point depressant lowers the lowest temperature at which a fluid can flow or be poured. Examples of suitable pour point depressants include polymethacrylates, polyacrylates, polyacrylamides, condensation products of haloparaffin waxes and aromatic compounds, vinyl polymers of carboxylic acids, and terpolymers of dialkyl fumarates, vinyl esters of fatty acids, and allyl vinyl ethers. Such additives can be present in the lubricating oil composition at 0.01 - 1.0 wt%.

[0117] Nonionic surfactant Nonionic surfactants such as alkylphenols can improve the handling properties of asphaltenes during engine operation. Examples of such materials include alkylphenols having an alkyl substituent from a straight-chain or branched alkyl group having 9 - 30 carbon atoms. Other examples include alkylbenzenols, alkylnaphthols, and aldehyde condensates of alkylphenols, where the aldehyde is formaldehyde such that the condensate becomes a methylene-bridged alkylphenol. Such additives can be present in the lubricating oil composition at 0.1 - 20 wt%.

[0118] Marker The lubricating oil composition of the present invention may contain a dye or marker component, such as a tracer, which are particularly suitable for marking lubricants to protect brand integrity, prevent misidentification, and aid in the identification of leaks. The most useful types of markers or dyes are those that allow for easy extraction, measurement, and / or identification from the marked liquid. Many additives and tracers that have been proposed for use or are currently used for marking lubricants or tags include colorants and fluorescent dyes (e.g., diazo dyes, anthraquinone dyes, phthalain dyes, etc.), radioactive substances, metal compounds or complexes (e.g., metal-organic compounds, metal salts, metal oxides, metal coordination complexes, etc.), and various specific compounds that react in combination with a selected agent to yield a brightly colored derivative.

[0119] Examples of markers include materials selected from the group consisting of barium sulfate, bismuth trioxide, iodine, iodide, titanium oxide, zirconium oxide, gold, platinum, silver, tantalum, niobium, stainless steel, and combinations thereof. Certain metal soaps, fatty acid metal soaps, metal carboxylates, or known metal desiccants supplied as solutions containing metals such as cobalt, lead, magnesium, titanium, zirconium, manganese, rhodium, platinum, aluminum, manganese, calcium, cerium, copper, nickel, vanadium, barium, tungsten, vanadium, and zinc, and materials such as mixtures thereof are also useful as lubricant markers. Examples of zirconium-containing materials can include zirconium carboxylates such as zirconium 2-ethylhexanoate, zirconium octanoate, and zirconium salicylate materials.

[0120] Use of the Lubricating Oil Composition The lubricant composition can be effective as a cylinder lubricant for compression ignition internal combustion engines, including marine diesel engines, stationary gas engines, and the like.

[0121] The internal combustion engine can be a two-stroke engine. In one embodiment, the internal combustion engine is a marine diesel engine. In certain embodiments, the marine diesel engine can be a low-speed crosshead two-stroke compression ignition engine having a speed of 200 rpm or less (e.g., 60 - 200 rpm).

[0122] The marine diesel engine can be lubricated by a marine diesel cylinder lubricant (e.g., generally in a two-stroke engine).

[0123] The term "marine" is not limited to engines used in watercraft; as understood in the art, it includes those for other industrial applications, such as for auxiliary power generation for main propulsion, and stationary land-based engines for power generation.

[0124] In some embodiments, the internal combustion engine may be fueled by residual fuel, marine residual fuel, low sulfur marine residual fuel, marine distillate fuel, low sulfur marine distillate fuel, or high sulfur fuel.

[0125] The internal combustion engine may also operate on "gaseous fuel", for example, a fuel mainly composed of methane (e.g., natural gas), biogas, gasified liquefied gas, or gasified liquefied natural gas (LNG).

Examples

[0126] The following exemplary examples are intended to be non-limiting and demonstrate the effect of using a suitable olefin copolymer thickener in combination with a light neutral base oil or a heavy neutral base oil to provide various viscosity levels.

[0127] The following components were used in the formulation of the marine lubricating oil composition of the examples. Generally, the marine lubricating oil composition of the examples included a lubricating viscous oil (base oil component), a thickener, and a set of additives.

[0128] The base oil components used in the formulation of the examples included the following:

[0129] XOM 150N: ExxonMobil CORE® 150N Group I lubricating oil, kinematic viscosity at 100 °C of 5.1 mm 2 / s

[0130] XOM 600N: ExxonMobil CORE® 600N: Group I lubricating oil, kinematic viscosity at 100 °C of 12.4 mm 2 / s

[0131] XOM 2500BS: ExxonMobil CORE® 2500BS: Group I bright stock lubricating oil, kinematic viscosity at 100 °C of 30.6 mm 2 / s

[0132] RLOP 600R: Chevron 600R RLOP: Group II lubricating oil, kinematic viscosity at 100 °C 12.0 mm 2 / s

[0133] RLOP 220R: Chevron 220 RLOP: Group II lubricating oil, kinematic viscosity at 100 °C 6.4 mm 2 / s

[0134] The olefin copolymer thickener used in the formulations of the examples was a concentrate of an olefin copolymer, specifically an ethylene-propylene copolymer, made with a diluent. Therefore, in the tables shown below, the weight percentages listed for the OCP thickeners are shown on a received basis rather than an active substance basis. To obtain the weight percentage on an active substance basis of the olefin copolymer, it is necessary to multiply the weight percentage listed for the OCP thickener by the weight percentage of the olefin copolymer present in the OCP thickener.

[0135] OCP-1: A concentrate having 6.30 wt% of a 50 SSI olefin copolymer in Group II diluent oil, containing 60% ethylene, and having a number average molecular weight (Mn) of 112,000 g / mol.

[0136] The set of additives used in the formulations of the examples included the following.

[0137] Additive set A: 6.92 wt% of an oil concentrate of calcium sulfonate detergent of BN420 (38.7 wt% diluent oil), 6.0 wt% of an oil concentrate of calcium sulfonate detergent of BN17 (50.0 wt% diluent oil), and C 20 ~C 24 9.0 wt% of an oil concentrate of calcium phenate sulfide detergent of BN95 derived from isomerized alpha olefin of C

[0138] Additive set B: C20 ~C 24 5.0 wt% of an oil concentrate (40 wt% diluent oil) of calcium sulfide phenate detergent BN260 derived from isomerized alpha olefin, and C 20 ~C 24 4.0 wt% of an oil concentrate (33.0 wt% diluent oil) of calcium overbased carboxylate detergent BN410 derived from isomerized alpha olefin, and C 20 ~C 24 5.45 wt% of an oil concentrate (20 wt% diluent oil) of calcium overbased carboxylate detergent BN180 derived from isomerized normal alpha olefin, 0.2 wt% of an oil concentrate (32 wt% diluent oil) of bis-succinimide dispersant derived from 1000 MW PIB, 1.5 wt% of antioxidant, 0.11 wt% of antifoaming agent, and diluent oil.

[0139] Additive set C: 1.03 wt% of an oil concentrate (38.7 wt% diluent oil) of calcium sulfonate detergent BN420, 6.0 wt% of an oil concentrate (50.0 wt% diluent oil) of calcium sulfonate detergent BN17, and C 20 ~C 24 9.0 wt% of an oil concentrate (20 wt% diluent oil) of calcium sulfide phenate detergent BN95 derived from isomerized alpha olefin, 0.2 wt% of an oil concentrate (32 wt% diluent oil) of bis-succinimide dispersant derived from 1000 MW PIB, 1.5 wt% of antioxidant, and 0.11 wt% of antifoaming agent.

[0140] Additive set D: C 20 ~C 24 3.0 wt% of an oil concentrate (40 wt% diluent oil) of calcium sulfide phenate detergent BN260 derived from isomerized alpha olefin, and C 20 ~C 24 0.3 wt% of an oil concentrate (33.0 wt% diluent oil) of calcium overbased carboxylate detergent BN410 derived from isomerized alpha olefin, and C 20 ~C 24An oil concentrate (20 wt% diluent oil) of a basic calcium carboxylate detergent of BN180 derived from isomerized normal alpha olefin at 2.9 wt%, an oil concentrate (32 wt% diluent oil) of a bis-succinimide dispersant derived from 1000 MW PIB at 0.2 wt%, an antioxidant at 1.5 wt%, and an antifoaming agent at 0.11 wt%.

[0141] For the following examples, the degree of oxidation stability was evaluated using the tests described below. The results of each example are shown in Tables 2 to 5.

[0142] Test Method DSC Oxidation Test In accordance with ASTM D-6186, the thin-film oxidation stability of the test oil was evaluated using a DSC test. During the test, the heat flow entering and leaving the test oil in the sample cup was compared with that in the reference cup. The oxidation onset temperature is the temperature at which the oxidation of the test oil begins. The oxidation induction time is the time at which the oxidation of the test oil begins. A larger oxidation induction time means better performance. The oxidation reaction is exothermic and is clearly indicated by the heat flow. The oxidation induction time is calculated to evaluate the thin-film oxidation stability of the test oil.

[0143] Modified Institute of Petroleum 48 (MIP-48) Test The MIP-48 test consists of a heat part and an oxidation part. Between both parts of the test, the test sample is heated. In the heat part of the test, nitrogen is flowed through the heated oil sample for 24 hours, and in parallel, air is flowed through the heated oil sample for 24 hours between the oxidation parts of the test. The sample is cooled and the viscosities of both samples are determined. The viscosity increase of the test oil caused by oxidation is determined and the influence of heat is corrected. The viscosity increase based on oxidation of each marine lubricating oil composition is calculated by subtracting the kinematic viscosity at 200 °C of the nitrogen-flushed sample from the kinematic viscosity at 200 °C of the air-flushed sample, and dividing the result of the subtraction by the kinematic viscosity at 200 °C of the nitrogen-flushed sample. This is done to correct for any possible evaporation effects or other thermal effects during the test and thereby focus on the influence of oxidation. With this correction, negative values may occur. Test oils that exhibit better stability with respect to the viscosity increase based on oxidation will result in lower absolute value %.

[0144] Results Example 1 and Comparative Example A Example 1 and Comparative Example A were formulated into a marine cylinder lubricant composition with a viscosity grade of SAE 50 (kinematic viscosity at 100 °C of 18.5 mm 2 / s) and a BN of 40 using an additive package A of 24.98 wt%. The finished oil lubricant of Comparative Example A was formulated using a large amount of heavy neutral oil Chevron RLOP 600R Group II base oil and a small amount of XOM Core 2500BS to achieve an appropriate lubricating oil viscosity. The finished oil lubricant of Example 1 contained a combination of light neutral oil Chevron 220R Group II base oil and an olefin copolymer thickener to achieve an appropriate lubricating oil viscosity. Each lubricant was evaluated for oxidation stability using a DSC oxidation test. The results of each example are shown in Table 2 below. The weight percentages listed for the OCP thickener are those for the acceptance criteria.

Table 2

[0145] As is clear from the results shown in Table 2, the marine cylinder lubricant composition containing the combination of light neutral oil 220R and an olefin copolymer thickener exhibited surprisingly better oxidation performance than Comparative Example A, since the oxidation induction time of the examples of the present invention was greater than that of the comparative examples. Therefore, in certain embodiments, a marine cylinder lubricant formulation comprising a combination of a light neutral oil and an olefin copolymer thickener can have enhanced performance compared to a marine cylinder lubricant formulation that does not contain an olefin copolymer thickener.

[0146] Example 2 and Comparative Example B Example 2 and Comparative Example B were formulated into a marine cylinder lubricant composition having a viscosity grade of SAE 50 with a BN of 40 (kinematic viscosity at 100 °C of 18.5 mm 2 / s) using a 17.12 wt% additive package B. The finished oil lubricant of Comparative Example B was formulated using a large amount of heavy neutral oil Chevron RLOP 600R Group II base oil and a small amount of XOM Core 2500BS to achieve an appropriate lubricating oil viscosity. The finished oil lubricant of Example 2 contained a combination of light neutral oil Chevron 220R Group II base oil and an olefin copolymer thickener to achieve an appropriate lubricating oil viscosity. Each lubricant was evaluated for oxidation stability using a DSC oxidation test. The results of each example are shown in Table 3 below. The weight percentages listed for the OCP thickener are those at the acceptance criteria.

Table 3

[0147] As is clear from the results shown in Table 3, the marine cylinder lubricant composition containing the combination of light neutral oil 220R and an olefin copolymer thickener exhibited surprisingly better oxidation performance than Comparative Example B, since the oxidation induction time of the examples of the present invention was greater than that of the comparative examples. Therefore, in certain embodiments, a marine cylinder lubricant formulation comprising a combination of a light neutral oil and an olefin copolymer thickener can have enhanced performance compared to a marine cylinder lubricant formulation that does not contain an olefin copolymer thickener.

[0148] Example 3 and Comparative Example C Example 3 and Comparative Example C were formulated into a marine cylinder lubricant composition of SAE 50 viscosity grade with a BN of 15 (kinematic viscosity at 100 °C of 18.5 mm 2 / s) using a formulation of 18.78 wt% of Additive Package C. The finished oil lubricant of Comparative Example C was formulated using a large amount of heavy neutral oil Chevron RLOP 600R Group II base oil and a small amount of XOM Core 2500BS to achieve an appropriate lubricating oil viscosity. The finished oil lubricant of Example 3 contained a combination of light neutral oil Chevron 220R Group II base oil and an olefin copolymer thickener to achieve an appropriate lubricating oil viscosity. Each lubricant was evaluated for oxidation stability using a DSC oxidation test. The results of each example are shown in Table 4 below. The weight percentages listed for the OCP thickener are those for the acceptance criteria.

Table 4

[0149] As is apparent from the results shown in Table 4, where the oxidation induction time of the examples of the present invention is greater than that of the comparative examples, the marine cylinder lubricant composition containing a combination of light neutral oil 220R and an olefin copolymer thickener exhibited surprisingly better oxidation performance than Comparative Example C. Thus, in certain embodiments, a marine cylinder lubricant formulation comprising a combination of a light neutral oil and an olefin copolymer thickener can have enhanced performance compared to a marine cylinder lubricant formulation that does not contain an olefin copolymer thickener.

[0150] Example 4 and Comparative Example D Example 4 and Comparative Example D were formulated into a marine cylinder lubricant composition of SAE 50 viscosity grade with a BN of 15 (kinematic viscosity at 100 °C of 18.5 mm 2It was formulated into a marine cylinder lubricant composition ( / s). The finished oil lubricant of Comparative Example D was formulated using a large amount of heavy neutral oil Chevron RLOP 600R Group II base oil and a small amount of XOM Core 2500BS to achieve an appropriate lubricating oil viscosity. The finished oil lubricant of Example 4 contained a combination of a light neutral oil Chevron 220R Group II base oil and an olefin copolymer thickener to achieve an appropriate lubricating oil viscosity. Each lubricant was evaluated for oxidation stability using a DSC oxidation test. The results of each example are shown in Table 5 below.

Table 5

[0151] As is clear from the results shown in Table 5, where the oxidation induction time of the examples of the present invention is greater than that of the comparative examples, the marine cylinder lubricant composition containing a combination of light neutral oil 220R and an olefin copolymer thickener exhibited surprisingly better oxidation performance than Comparative Example D. Thus, in certain embodiments, a marine cylinder lubricant formulation comprising a combination of a light neutral oil and an olefin copolymer thickener can have enhanced performance compared to a marine cylinder lubricant formulation that does not contain an olefin copolymer thickener.

[0152] It should be understood that the specific embodiments described above are presented by way of example, and that these embodiments may admit of various modifications and alternative forms and can be used in any suitable combination. Furthermore, it should be understood that the claims are not intended to be limited to the specific forms disclosed, but rather are intended to cover all modifications, equivalents, and alternative forms falling within the spirit and scope of the present disclosure.

Claims

1. A marine diesel cylinder lubricating oil composition comprising: (a) a large amount of lubricating viscous oil; and (b) one or more olefin copolymers having a number average molecular weight of 30,000 to 120,000 wherein the marine diesel engine lubricating oil composition has a TBN of less than 70 mg KOH / g, and further, the marine diesel engine lubricating oil composition is a single grade lubricating oil composition that meets the 2015 January revised SAE J300 requirements for SAE40, SAE50 or SAE60 single grade lubricating oils.

2. The one or more olefin copolymers are bimodal and the ethylene unit content is in the range of 30% to 80% by weight based on the weight of the olefin copolymer. The composition according to claim 1.

3. The composition according to claim 1, wherein the one or more olefin copolymers are present in the lubricating oil composition at 0.5 to 5 wt% on an active substance basis.

4. The composition according to claim 1, wherein the one or more olefin copolymers are present in the lubricating oil composition at 1 to 2 wt% on an active substance basis.

5. The composition according to claim 1, wherein the one or more olefin copolymers are the only viscosity modifier present in the lubricating oil composition.

6. The composition according to claim 1, wherein the lubricating oil composition does not contain bright stock.

7. The composition according to claim 1, wherein the lubricating oil composition has a sulfuric acid ash content of 1.5 wt% or more.

8. The composition according to claim 1, wherein the lubricating oil composition has a TBN of 15 to 40 mg KOH / g.

9. The composition according to claim 1, wherein the one or more olefin copolymers consist of one or more ethylene-propylene copolymers.

10. The oil of lubricating viscosity has a viscosity of 4.0 mm at 100° C. ２ / s ~ 8.5 mm ２ The composition according to claims 1 to 9, having a kinematic viscosity of less than 1 / s.

11. The lubricating viscous oil has a kinematic viscosity of 8.5 mm ２ / s to 15.0 mm ２ / s at 100°C, and the composition according to any one of claims 1 to 9.

12. A method for increasing the viscosity of a cylinder lubricating oil composition in a marine diesel internal combustion engine, comprising adding to the engine (a) a large amount of lubricating viscous oil; and (b) one or more olefin copolymers having a number average molecular weight of 30,000 to 120,000 wherein the marine diesel lubricating oil composition has a TBN of less than 70 mg KOH / g, and further, the marine diesel lubricating oil composition is a single grade lubricating oil composition that meets the 2015 January revised SAE J300 requirements for SAE40, SAE50 or SAE60 single grade lubricating oils.

13. ​ The method according to claim 12, wherein the one or more olefin copolymers are present at 1 to 2 wt% of the lubricating oil composition based on the active substance.

14. The method according to claim 12, wherein the one or more olefin copolymers are the only viscosity modifier present in the lubricating oil composition.

15. The method according to claim 12, wherein the lubricating oil composition does not contain bright stock.

16. The method according to claim 12, wherein the lubricating oil composition has a sulfuric acid ash content of 1.5 wt% or more.

17. The method according to claim 12, wherein the lubricating oil composition has a TBN of 15 to 40 mg KOH / g.

18. The method according to claim 12, wherein the one or more olefin copolymers consist of one or more ethylene-propylene copolymers.

19. The lubricating viscous oil has a kinematic viscosity of 4.0 mm ２ / s to less than 8.5 mm ２ / s at 100°C, and the method according to claims 13 to 18.

20. The lubricating viscous oil has a kinematic viscosity of 8.5 mm ２ / s to 15.0 mm ２ / s, and the method according to claims 13 to 18.

21. A method for suppressing deposit formation in an internal combustion engine, comprising operating the internal combustion engine with a cylinder lubricating oil composition comprising (a) a large amount of lubricating viscous oil; and (b) one or more olefin copolymers having a number average molecular weight of 30,000 to 120,000 wherein the marine diesel lubricating oil composition has a TBN of less than 70 mg KOH / g, and further wherein the marine diesel lubricating oil composition is a single grade lubricating oil composition that meets the specifications of the January 2015 revised SAE J300 requirements for SAE40, SAE50 or SAE60 single grade lubricating oils.

22. The method according to claim 21, wherein the one or more olefin copolymers are present at 1 to 2 wt% of the lubricating oil composition based on the active substance.

23. The method according to claim 21, wherein the one or more olefin copolymers are the only viscosity modifier present in the lubricating oil composition.

24. The method according to claim 21, wherein the lubricating oil composition does not contain bright stock.

25. The method according to claim 21, wherein the lubricating oil composition has a sulfuric acid ash content of 1.5 wt% or more.

26. The method according to claim 21, wherein the lubricating oil composition has a TBN of 15 mg KOH / g to less than 40 mg KOH / g.

27. The method according to claim 21, wherein the one or more olefin copolymers consist of one or more ethylene-propylene copolymers.

28. The lubricating viscous oil has a kinematic viscosity at 100 °C of 4.0 mm ２ / s to less than 8.5 mm ２ / s, and the method according to claims 21 to 27.

29. The lubricating viscous oil has a kinematic viscosity of 8.5 mm ２ / s to 15.0 mm ２ / s, and the method according to claims 21 to 27.

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