Lubricant composition

Abstract

To provide a lubricant composition that effectively suppresses generation of deposits regardless of a use environment, offers superior fuel efficiency, and is suitable for internal combustion engines.SOLUTION: A lubricant composition includes a base oil (A) and a metal-based detergent (B). In the component (A), a content of a heavy fraction (Hf) with 32 or more carbon atoms is 14.0 mass% or more based on a total amount of the component (A). The component (B) includes overbased calcium salicylate (B1) with a base number of 100 mgKOH / g or more. In the component (B), a content of the component (B1) is 35.0 mass% or more based on a total amount of the component (B).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to lubricating oil compositions, internal combustion engines, and methods of lubricating internal combustion engines. [Background technology]

[0002] Internal combustion engines used in automobiles and the like are subject to various demands, such as compactness and high output, fuel economy, and compliance with exhaust gas regulations, and development is underway for lubricating oil compositions for use in internal combustion engines that can meet these demands. For example, Patent Document 1 discloses an invention relating to a lubricating oil composition containing 14 mass% or more of a fraction having a boiling point of 500 to 550°C and 5 mass% or more of a fraction having a boiling point exceeding 550°C, with the aim of providing a lubricating oil composition with improved performance in suppressing the formation of compressor deposits. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-196595 Summary of the Invention [Problem to be solved by the invention]

[0004] Meanwhile, as an environmentally friendly measure, development is underway on turbochargers equipped with EGR systems that re-intake and recirculate part of the exhaust gas. Turbochargers equipped with EGR systems are prone to engine oil deposits when the boost pressure is increased, which reduces the efficiency of the turbocharger. Furthermore, fuel economy is also required for internal combustion engines used in automobiles and other vehicles. In this situation, there is a demand for lubricating oil compositions that are highly effective in suppressing deposit formation, have excellent fuel economy, and can be suitably used in internal combustion engines, regardless of the operating environment. [Means for solving the problem]

[0005] As a result of extensive research, the present inventors have found that the above-mentioned problems can be solved by a lubricating oil composition that uses a base oil in which the content of heavy fraction (Hf) having 32 or more carbon atoms is adjusted to fall within a specified range, and a metallic detergent containing an overbased calcium salicylate having a specified base number in a specified proportion. Specifically, the present invention discloses the following aspects. [1] A base oil (A) and a metal-based detergent (B), The content of heavy fraction (Hf) having a carbon number of 32 or more in component (A) is 14.0 mass% or more based on the total amount of component (A), Component (B) contains an overbased calcium salicylate (B1) having a base number of 100 mg KOH / g or more, The content of component (B1) in component (B) is 35.0 mass% or more based on the total amount of component (B). Lubricating oil composition. [2] An internal combustion engine filled with the lubricating oil composition described in [1] above. [3] A method for lubricating an internal combustion engine, comprising applying the lubricating oil composition according to [1] above to the internal combustion engine. [Effects of the Invention]

[0006] The lubricating oil composition of a preferred embodiment of the present invention is excellent in the effect of suppressing deposit formation, detergency and stability, and fuel economy, regardless of the environment in which it is used, and therefore can be suitably used, for example, for lubricating internal combustion engines. DETAILED DESCRIPTION OF THE INVENTION

[0007] The upper and lower limits of the numerical ranges described herein can be combined in any combination. For example, if a numerical range is described as "preferably 30 to 100, more preferably 40 to 80," the range "30 to 80" and the range "40 to 100" are also included in the numerical ranges described herein. Furthermore, for example, when a numerical range is described as "preferably 30 or more, more preferably 40 or more, and preferably 100 or less, more preferably 80 or less," the range of "30 to 80" and the range of "40 to 100" are also included in the numerical range described in this specification. In other words, in specifying the upper and lower limits described in this specification, the numerical range from the lower limit to the upper limit can be specified by appropriately selecting from the respective options and combining them as desired. Furthermore, as a numerical range described in this specification, for example, "60 to 100" means a range of "60 or more and 100 or less." In addition, the various features described as preferred embodiments in this specification can be combined in multiple ways.

[0008] [Constitution of lubricating oil composition] The lubricating oil composition of one embodiment of the present invention contains a specific base oil (A) and a specific metal-based detergent (B), and may further contain other components as long as the effects of the present invention are not impaired. For example, from the viewpoint of providing a lubricating oil composition with low temperature dependency of viscosity and good fuel economy, the lubricating oil composition of one embodiment of the present invention may further contain a viscosity index improver (C).

[0009] In the lubricating oil composition of one embodiment of the present invention, the total content of components (A) and (B) is, based on the total amount (100 mass%) of the lubricating oil composition, preferably 50 mass% or more, more preferably 60 mass% or more, more preferably 65 mass% or more, even more preferably 70 mass% or more, even more preferably 75 mass% or more, still more preferably 80 mass% or more, and particularly preferably 83 mass% or more, and may also be 100 mass% or less, 99.9 mass% or less, 99.0 mass% or less, 97.0 mass% or less, 95.0 mass% or less, 92.0 mass% or less, or 90.0 mass% or less.

[0010] In the lubricating oil composition of one embodiment of the present invention, the total content of components (A), (B), and (C) is, based on the total amount (100 mass%) of the lubricating oil composition, preferably 55 mass% or more, more preferably 60 mass% or more, more preferably 65 mass% or more, even more preferably 70 mass% or more, even more preferably 75 mass% or more, still more preferably 80 mass% or more, and particularly preferably 85 mass% or more, and may also be 100 mass% or less, 99.9 mass% or less, 99.0 mass% or less, 97.0 mass% or less, 95.0 mass% or less, 92.0 mass% or less, or 90.0 mass% or less.

[0011] Hereinafter, each component contained in the lubricating oil composition of one embodiment of the present invention will be described in detail.

[0012] <Component (A): Base oil> In the lubricating oil composition of one embodiment of the present invention, the base oil used as component (A) may be one or more selected from mineral oils and synthetic oils. Examples of mineral oils include atmospheric residues obtained by atmospheric distillation of crude oils such as paraffinic crude oil, intermediate crude oil, and naphthenic crude oil; distillates obtained by vacuum distillation of these atmospheric residues; and refined oils obtained by subjecting the distillates to one or more refining treatments such as solvent deasphalting, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, and hydrorefining.

[0013] Examples of synthetic oils include poly-α-olefins such as α-olefin homopolymers and α-olefin copolymers (e.g., α-olefin copolymers having 8 to 14 carbon atoms, such as ethylene-α-olefin copolymers); isoparaffins; polyalkylene glycols; ester-based oils such as polyol esters, dibasic acid esters, and phosphate esters; ether-based oils such as polyphenyl ethers; alkylbenzenes; alkylnaphthalenes; and synthetic oils (GTL) obtained by isomerizing wax produced from natural gas by the Fischer-Tropsch process or the like (GTL wax (Gas To Liquids WAX)).

[0014] The base oil (A) used in one embodiment of the present invention satisfies the following requirement (I). Requirement (I): The content of heavy components (Hf) having a carbon number of 32 or more in component (A) is 14.0 mass% or more based on the total amount of component (A). By using a base oil (A) adjusted to satisfy requirement (I), it is possible to obtain a lubricating oil composition with good fluidity, with the amount of evaporation being suppressed, even when used under high-temperature and / or high-pressure environments where the base oil is likely to evaporate. As a result, the lubricating oil composition of one embodiment of the present invention with good fluidity can distribute the metal-based detergent of component (B) throughout the lubricated surface, and can effectively suppress the generation of deposits. On the other hand, lubricating oil compositions in which the content of heavy fractions (Hf) having 32 or more carbon atoms in component (A) is less than 14.0 mass % tend to be unable to sufficiently suppress evaporation under high temperature and / or high pressure environments, resulting in reduced fluidity and insufficient effect in suppressing deposit formation.

[0015] From the viewpoint of providing a lubricating oil composition that maintains good fluidity and is highly effective in suppressing deposit formation even when used in a high-temperature and / or high-pressure environment, the content of heavy fractions (Hf) having 32 or more carbon atoms is preferably 15.0% by mass or more, more preferably 16.0% by mass or more, even more preferably 17.0% by mass or more, still more preferably 18.0% by mass or more, and particularly preferably 19.0% by mass or more, based on the total amount (100% by mass) of component (A); and from the viewpoint of providing a lubricating oil composition that has good fuel economy properties, it is preferably 40.0% by mass or less, more preferably 37.0% by mass or less, more preferably 35.0% by mass or less, more preferably 33.0% by mass or less, even more preferably 30.0% by mass or less, even more preferably 27.0% by mass or less, still more preferably 25.0% by mass or less, and particularly preferably 23.0% by mass or less.

[0016] Furthermore, the base oil (A) used in one embodiment of the present invention preferably satisfies at least one of the following requirements (IIa) and (IIb), and more preferably satisfies both of the following requirements (IIa) and (IIb): Requirement (II): The ratio of the content of light fraction (Lf) having 21 or less carbon atoms to the content of heavy fraction (Hf) having 32 or more carbon atoms in component (A) [(Lf) / (Hf)] is 0.05 or more by mass. Requirement (III): The content of light fraction (Lf) having 21 or less carbon atoms in component (A) is 1.0 mass% or more based on the total amount of component (A). By using a base oil (A) adjusted to satisfy requirement (II) and / or requirement (III), it is possible to obtain a lubricating oil composition with improved fuel economy.

[0017] From the viewpoint of obtaining a lubricating oil composition with further improved fuel economy, the content ratio [(Lf) / (Hf)] is preferably 0.07 or more, more preferably 0.09 or more, more preferably 0.10 or more, even more preferably 0.11 or more, still more preferably 0.12 or more, particularly preferably 0.13 or more, and may further be 0.15 or more, 0.17 or more, 0.20 or more, 0.23 or more, 0.25 or more, 0.27 or more, or 0.30 or more. Furthermore, from the viewpoint of providing a lubricating oil composition that maintains good fluidity and has a higher effect of suppressing deposit formation even when used in a high-temperature and / or high-pressure environment, the content ratio [(Lf) / (Hf)] is preferably 0.80 or less, more preferably 0.70 or less, more preferably 0.60 or less, even more preferably 0.55 or less, still more preferably 0.50 or less, and particularly preferably 0.48 or less.

[0018] From the viewpoint of obtaining a lubricating oil composition with further improved fuel economy, the content of the light fraction (Lf) having 21 or less carbon atoms is, based on the total amount (100 mass%) of component (A), preferably 1.5 mass% or more, more preferably 1.7 mass% or more, even more preferably 2.0 mass% or more, still more preferably 2.3 mass% or more, and particularly preferably 2.5 mass% or more, and may further be 2.7 mass% or more, 3.0 mass% or more, 3.5 mass% or more, 4.0 mass% or more, 4.5 mass% or more, 5.0 mass% or more, 5.5 mass% or more, 6.0 mass% or more, 6.5 mass% or more, or 7.0 mass% or more. Furthermore, from the viewpoint of obtaining a lubricating oil composition that maintains good fluidity and is more effective in suppressing deposit formation even when used in a high-temperature and / or high-pressure environment, the content of light fractions (Lf) having 21 or less carbon atoms is preferably 25.0 mass% or less, more preferably 20.0 mass% or less, more preferably 17.0 mass% or less, more preferably 15.0 mass% or less, even more preferably 12.0 mass% or less, even more preferably 10.0 mass% or less, still more preferably 9.5 mass% or less, and particularly preferably 9.0 mass% or less, based on the total amount (100 mass%) of component (A).

[0019] In one embodiment of the present invention, the content of the middle fraction (Mf) having from 22 to 31 carbon atoms in component (A) is, based on the total amount (100 mass%) of component (A), preferably 35.0 mass% or more, more preferably 40.0 mass% or more, more preferably 45.0 mass% or more, even more preferably 50.0 mass% or more, even more preferably 55.0 mass% or more, still more preferably 60.0 mass% or more, particularly preferably 65.0 mass% or more, and is preferably 85 mass% or less, more preferably 83.5 mass% or less, more preferably 81.0 mass% or less, even more preferably 80.0 mass% or less, even more preferably 79.0 mass% or less, still more preferably 78.0 mass% or less, and particularly preferably 77.0 mass% or less.

[0020] In this specification, the contents of components with each carbon number constituting component (A), the content ratio of heavy fraction (Hf) having 32 or more carbon atoms, the content ratio of light fraction (Lf) having 21 or less carbon atoms, and the content ratio of medium fraction (Mf) having 22 to 31 carbon atoms are values ​​measured in accordance with the method described in the Examples.

[0021] The kinematic viscosity at 40°C of the component (A) used in one embodiment of the present invention is preferably 10 to 120 mm 2 / s, more preferably 15 to 100 mm 2 / s, preferably 20 to 80 mm 2 / s, more preferably 25 to 70 mm 2 / s, and even more preferably 30 to 60 mm 2 / s, particularly preferably 35 to 50 mm2 / s.

[0022] The viscosity index of component (A) used in one embodiment of the present invention is preferably 80 or greater, more preferably 100 or greater, even more preferably 110 or greater, still more preferably 120 or greater, and particularly preferably 130 or greater.

[0023] The kinematic viscosity and viscosity index refer to values ​​measured and calculated in accordance with JIS K2283:2000. In one embodiment of the present invention, when a mixed oil of two or more base oils is used as component (A), the mixed oil preferably has a kinematic viscosity and a viscosity index within the above ranges. Also, the weighted average of the kinematic viscosity and the viscosity index calculated from the content ratios of the base oils constituting the mixed oil preferably falls within the above ranges.

[0024] In the lubricating oil composition of one embodiment of the present invention, the content of component (A) is, based on the total amount (100 mass%) of the lubricating oil composition, preferably 40 mass% or more, more preferably 50 mass% or more, more preferably 60 mass% or more, even more preferably 65 mass% or more, even more preferably 70 mass% or more, still more preferably 75 mass% or more, and particularly preferably 80 mass% or more, and may be 99.9 mass% or less, 99.5 mass% or less, 99.0 mass% or less, 97.0 mass% or less, 95.0 mass% or less, 92.0 mass% or less, or 90.0 mass% or less.

[0025] <Component (B): Metallic detergent> The lubricating oil composition of one embodiment of the present invention contains a metallic detergent (B) containing an overbased calcium salicylate (B1) having a base number of 100 mgKOH / g or more. The component (B) and the component (B1) used in one embodiment of the present invention may be used alone or in combination of two or more kinds. By including an overbased calcium salicylate (B1) as the metallic detergent (B), it is possible to obtain a lubricating oil composition that not only improves detergency and stability in high-temperature environments but also has excellent fuel economy. The component (B) used in one embodiment of the present invention may be used alone or in combination of two or more types.

[0026] In one embodiment of the lubricating oil composition of the present invention, from the viewpoint of improving detergency and stability in high-temperature environments and also providing a lubricating oil composition with excellent fuel economy, the content of component (B1) in component (B) is 35.0 mass% or more based on the total amount (100 mass%) of component (B) contained in the lubricating oil composition. Lubricating oil compositions containing less than 50% by mass of component (B1) are prone to problems with detergency and stability in high-temperature environments, and may also exhibit reduced fuel economy. From the above viewpoints, the content of component (B1) in component (B) is, based on the total amount (100 mass%) of component (B) contained in the lubricating oil composition, preferably 37.0 mass% or more, more preferably 40.0 mass% or more, more preferably 45.0 mass% or more, even more preferably 50.0 mass% or more, even more preferably 55.0 mass% or more, still more preferably 60.0 mass% or more, and particularly preferably 63.0 mass% or more, and may also be 100 mass% or less, 99.0 mass% or less, 98.0 mass% or less, 95.0 mass% or less, 90.0 mass% or less, 85.0 mass% or less, 80.0 mass% or less, 75.0 mass% or less, or 70.0 mass% or less.

[0027] An example of the component (B1) used in one embodiment of the present invention is a compound represented by the following general formula (b-1). [ka]

[0028] In the above general formula (b-1), R is a hydrogen atom or a hydrocarbon group having 1 to 18 carbon atoms. Examples of hydrocarbon groups that can be selected as R include alkyl groups having 1 to 18 carbon atoms, alkenyl groups having 1 to 18 carbon atoms, cycloalkyl groups having 3 to 18 ring carbon atoms, aryl groups having 6 to 18 ring carbon atoms, alkylaryl groups having 7 to 18 carbon atoms, and arylalkyl groups having 7 to 18 carbon atoms.

[0029] The component (B1) used in one embodiment of the present invention is overbased and has a base number of 100 mgKOH / g or more. From the viewpoint of further improving detergency and stability in high-temperature environments and providing a lubricating oil composition that is also more excellent in fuel economy, the base number of component (B1) used in one embodiment of the present invention is preferably 120 mgKOH / g or more, more preferably 150 mgKOH / g or more, more preferably 170 mgKOH / g or more, even more preferably 200 mgKOH / g or more, even more preferably 220 mgKOH / g or more, still more preferably 250 mgKOH / g or more, and particularly preferably 270 mgKOH / g or more, and may also be 600 mgKOH / g or less, 550 mgKOH / g or less, 500 mgKOH / g or less, 450 mgKOH / g or less, or 400 mgKOH / g or less. In this specification, the term "base number" refers to a value measured by the perchloric acid method in accordance with "9. Potentiometric titration method (base number - perchloric acid method)" of JIS K2501 "Petroleum products and lubricants - Testing method for neutralization number."

[0030] In the lubricating oil composition of one embodiment of the present invention, from the viewpoint of further improving detergency and stability in high-temperature environments and providing a lubricating oil composition with excellent fuel economy, the content of component (B1) in terms of calcium atoms, based on the total amount (100% by mass) of the lubricating oil composition, is preferably 0.01% by mass or more, more preferably 0.05% by mass or more, more preferably 0.07% by mass or more, even more preferably 0.10% by mass or more, still more preferably 0.12% by mass or more, and particularly preferably 0.14% by mass or more, and is preferably 0.80% by mass or less, 0.70% by mass or less, 0.60% by mass or less, 0.50% by mass or less, 0.40% by mass or less, 0.30% by mass or less, 0.25% by mass or less, 0.22% by mass or less, or 0.20% by mass or less. In this specification, the calcium atom (Ca) content refers to a value measured in accordance with JPI-5S-38-92.

[0031] In the lubricating oil composition of one embodiment of the present invention, from the viewpoint of further improving detergency and stability in high-temperature environments and providing a lubricating oil composition with excellent fuel economy, the content of component (B1) is, based on the total amount (100 mass%) of the lubricating oil composition, preferably 0.10 mass% or more, more preferably 0.50 mass% or more, more preferably 0.70 mass% or more, even more preferably 1.00 mass% or more, still more preferably 1.20 mass% or more, and particularly preferably 1.40 mass% or more, and is preferably 8.00 mass% or less, 7.00 mass% or less, 6.00 mass% or less, 5.00 mass% or less, 4.00 mass% or less, 3.00 mass% or less, 2.50 mass% or less, 2.20 mass% or less, or 2.00 mass% or less.

[0032] The lubricating oil composition of one embodiment of the present invention may contain, as component (B), a metallic detergent (B2) other than component (B1), or may not contain any metallic detergent (B2) other than component (B1). When the component (B2) is contained, the component (B2) may be used alone or in combination of two or more kinds.

[0033] Examples of component (B2) used in one embodiment of the present invention include organic acid metal salt compounds containing a metal atom selected from alkali metals and alkaline earth metals. Specific examples include metal salicylates (excluding overbased calcium salicylates corresponding to component (B1)), metal phenates, and metal sulfonates, all of which contain a metal atom selected from alkali metals and alkaline earth metals. As the metal atom contained in the metallic detergent, sodium, calcium, magnesium or barium is preferred, with calcium being more preferred, from the viewpoint of providing a lubricating oil composition with improved high-temperature detergency.

[0034] The component (B2) used in one embodiment of the present invention may be any of a neutral salt, a basic salt, an overbased salt, and a mixture thereof. The base number of the component (B2) used in one embodiment of the present invention is preferably 0 to 600 mgKOH / g, more preferably 10 to 600 mgKOH / g, and even more preferably 20 to 500 mgKOH / g.

[0035] In the lubricating oil composition of one embodiment of the present invention, the content of component (B) calculated as a metal atom, based on the total amount (100 mass%) of the lubricating oil composition, is preferably 0.01 mass% or more, more preferably 0.05 mass% or more, more preferably 0.07 mass% or more, even more preferably 0.10 mass% or more, still more preferably 0.12 mass% or more, and particularly preferably 0.14 mass% or more, and is preferably 1.00 mass% or less, 0.90 mass% or less, 0.80 mass% or less, 0.70 mass% or less, 0.60 mass% or less, 0.50 mass% or less, 0.40 mass% or less, 0.30 mass% or less, 0.25 mass% or less, or 0.20 mass% or less. In this specification, the metal atom content refers to a value measured in accordance with JPI-5S-38-92.

[0036] In the lubricating oil composition of one embodiment of the present invention, the content of component (B) is, based on the total amount (100 mass%) of the lubricating oil composition, preferably 0.10 mass% or more, more preferably 0.50 mass% or more, more preferably 1.00 mass% or more, even more preferably 1.50 mass% or more, still more preferably 1.70 mass% or more, and particularly preferably 2.00 mass% or more, and may be 8.00 mass% or less, 7.00 mass% or less, 6.00 mass% or less, 5.00 mass% or less, 4.00 mass% or less, 3.70 mass% or less, 3.50 mass% or less, 3.20 mass% or less, 3.00 mass% or less, 2.70 mass% or less, or 2.50 mass% or less.

[0037] <Component (C): Viscosity index improver> The lubricating oil composition of one embodiment of the present invention may contain a viscosity index improver as component (C). By containing the viscosity index improver (C), it is possible to obtain a lubricating oil composition with reduced temperature dependency of viscosity and good fuel economy. The component (C) used in one embodiment of the present invention may be used alone or in combination of two or more types.

[0038] Examples of component (C) used in one embodiment of the present invention include polymers such as non-dispersed polymethacrylate, dispersed polymethacrylate, olefin copolymers (e.g., ethylene-propylene copolymers), dispersed olefin copolymers, and styrene copolymers (e.g., styrene-diene copolymers, styrene-isoprene copolymers). Component (C) used in one embodiment of the present invention may be a comb polymer having a structure in which the main chain has many three-pronged branching points from which high molecular weight side chains emerge, or may be a star polymer having a structure in which one atom, such as a carbon atom, is bonded to three or more chain polymers.

[0039] From the viewpoint of obtaining a lubricating oil composition having a small temperature dependency of viscosity and good fuel economy, and adjusting the viscosity grade of the lubricating oil composition to 0W-20 according to SAE J300:2015, it is preferable that component (C) used in one embodiment of the present invention is a combination of a comb polymer and a dispersant polymethacrylate. The content ratio of comb polymer to disperse polymethacrylate [comb polymer / disperse polymethacrylate] is preferably 20 / 80 or more, more preferably 40 / 60 or more, more preferably 55 / 45 or more, even more preferably 65 / 35 or more, even more preferably 75 / 25 or more, still more preferably 80 / 20 or more, particularly preferably 85 / 15 or more, and is preferably 99 / 1 or less, more preferably 98 / 2 or less, even more preferably 97 / 3 or less, still more preferably 96 / 4 or less, particularly preferably 95 / 5 or less.

[0040] From the viewpoint of obtaining a lubricating oil composition having a small temperature dependency of viscosity and good fuel economy properties, and adjusting the viscosity grade of the lubricating oil composition to 0W-30 according to SAE J300:2015, it is preferred that component (C) used in one embodiment of the present invention is a combination of a non-dispersant polymethacrylate and a dispersant polymethacrylate. The content ratio of non-dispersed polymethacrylate to dispersed polymethacrylate [non-dispersed polymethacrylate / dispersed polymethacrylate] is preferably 20 / 80 or more, more preferably 40 / 60 or more, more preferably 55 / 45 or more, even more preferably 65 / 35 or more, even more preferably 75 / 25 or more, still more preferably 80 / 20 or more, particularly preferably 85 / 15 or more, and is preferably 99 / 1 or less, more preferably 98 / 2 or less, even more preferably 97 / 3 or less, still more preferably 96 / 4 or less, particularly preferably 95 / 5 or less.

[0041] The weight average molecular weight (Mw) of the viscosity index improver used in one embodiment of the present invention is, from the viewpoint of providing a lubricating oil composition with low temperature dependency of viscosity and good fuel economy, preferably 10,000 or more, more preferably 30,000 or more, more preferably 50,000 or more, even more preferably 70,000 or more, even more preferably 100,000 or more, still more preferably 120,000 or more, and particularly preferably 150,000 or more, and may further be 170,000 or more, 200,000 or more, 250,000 or more, or 300,000 or more. Furthermore, from the viewpoint of providing a lubricating oil composition that can suppress the generation of deposits, it may be 1,000,000 or less, 900,000 or less, 800,000 or less, 700,000 or less, 650,000 or less, 600,000 or less, 550,000 or less, or 500,000 or less.

[0042] In the lubricating oil composition of one embodiment of the present invention, from the viewpoint of obtaining a lubricating oil composition having little temperature dependency of viscosity and good fuel economy, the content of component (C) converted to resin content is preferably 0.01% by mass or more, more preferably 0.10% by mass or more, more preferably 0.30% by mass or more, more preferably 0.50% by mass or more, even more preferably 0.70% by mass or more, even more preferably 0.90% by mass or more, still more preferably 1.10% by mass or more, and particularly preferably 1.30% by mass or more, based on the total amount (100% by mass) of the lubricating oil composition. Furthermore, from the viewpoint of providing a lubricating oil composition that can suppress the generation of deposits, the content of component (C) converted to resin content is preferably 4.0 mass% or less, more preferably 3.5 mass% or less, more preferably 3.0 mass% or less, even more preferably 2.5 mass% or less, still more preferably 2.2 mass% or less, and particularly preferably 2.0 mass% or less, based on the total amount (100 mass%) of the lubricating oil composition.

[0043] In addition, component (C) used in one embodiment of the present invention, as well as the pour point depressant and antifoaming agent described below, are often commercially available in the form of a solution dissolved in a diluent oil such as a mineral oil or a synthetic oil, taking into consideration handleability and solubility with component (A). In this specification, the contents of component (C), the pour point depressant, and the antifoaming agent refer to the contents calculated as solids, excluding the diluent oil.

[0044] <Lubricant additives> The lubricating oil composition of one embodiment of the present invention may further contain other lubricating oil additives in addition to components (B) to (C) as needed, provided that the effects of the present invention are not impaired. Examples of such lubricating oil additives include pour point depressants, antioxidants, friction modifiers, anti-wear agents, extreme pressure agents, metal deactivators, ashless dispersants, rust inhibitors, and anti-foaming agents. These lubricating oil additives may be used alone or in combination of two or more.

[0045] The content of each of these lubricating oil additives can be adjusted as appropriate within a range that does not impair the effects of the present invention, but is typically 0.001 to 15 mass%, preferably 0.005 to 10 mass%, and more preferably 0.01 to 5 mass%, for each additive independently, based on the total amount (100 mass%) of the lubricating oil composition.

[0046] [Pour point depressants] The lubricating oil composition of one embodiment of the present invention may further contain a pour point depressant. The pour point depressants may be used alone or in combination of two or more. Examples of pour point depressants used in one embodiment of the present invention include ethylene-vinyl acetate copolymers, condensates of chlorinated paraffin and naphthalene, condensates of chlorinated paraffin and phenol, polymethacrylates, and polyalkylstyrenes. The weight average molecular weight (Mw) of the pour point depressant used in one embodiment of the present invention may be 5,000 or more, 7,000 or more, 10,000 or more, 15,000 or more, 20,000 or more, 25,000 or more, 30,000 or more, 35,000 or more, 40,000 or more, 45,000 or more, 50,000 or more, 55,000 or more, or 60,000 or more, and may be 150,000 or less, 120,000 or less, 100,000 or less, 90,000 or less, or 80,000 or less.

[0047] [Antioxidants] The lubricating oil composition of one embodiment of the present invention may further contain an antioxidant. The antioxidants may be used alone or in combination of two or more. Examples of antioxidants used in one embodiment of the present invention include amine-based antioxidants such as alkylated diphenylamine, phenylnaphthylamine, and alkylated phenylnaphthylamine; phenol-based antioxidants such as 2,6-di-t-butylphenol, 4,4'-methylenebis(2,6-di-t-butylphenol), isooctyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, and n-octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate; and sulfur-based antioxidants such as phenothiazine, dioctadecyl sulfide, dilauryl-3,3'-thiodipropionate, and 2-mercaptobenzimidazole.

[0048] [Friction modifiers and anti-wear agents] The lubricating oil composition of one embodiment of the present invention may further contain a friction modifier or an anti-wear agent. The friction modifier or anti-wear agent may be used alone or in combination of two or more kinds. Examples of friction modifiers and anti-wear agents used in one embodiment of the present invention include sulfur-based compounds such as sulfurized olefins, dialkyl polysulfides, diaryl alkyl polysulfides, and diaryl polysulfides; phosphorus-based compounds such as phosphate esters, thiophosphate esters, phosphites, alkyl hydrogen phosphites, phosphate ester amine salts, and phosphites ester amine salts; organic molybdenum-based compounds such as molybdenum dithiocarbamate (MoDTC), molybdenum dithiophosphate (MoDTP), and amine salts of molybdenum acid; organic zinc-based compounds such as zinc dithiophosphate (ZnDTP) and zinc dithiocarbamate (ZnDTC); and ashless friction modifiers such as amine compounds, fatty acid esters, fatty acid amides, fatty acids, aliphatic alcohols, aliphatic ethers, urea-based compounds, and hydrazide-based compounds.

[0049] [Extreme pressure agents] The lubricating oil composition of one embodiment of the present invention may further contain an extreme pressure agent. The extreme pressure agents may be used alone or in combination of two or more. Examples of extreme pressure agents used in one embodiment of the present invention include sulfur-based compounds such as sulfurized olefins, dialkyl polysulfides, diaryl alkyl polysulfides, and diaryl polysulfides; and phosphorus-based compounds such as phosphate esters, thiophosphate esters, phosphite esters, alkyl hydrogen phosphites, phosphate ester amine salts, and phosphite ester amine salts.

[0050] [Metal deactivator] The lubricating oil composition of one embodiment of the present invention may further contain a metal deactivator. The metal deactivators may be used alone or in combination of two or more. Examples of the metal deactivator used in one embodiment of the present invention include benzotriazole, triazole derivatives, benzotriazole derivatives, and thiadiazole derivatives.

[0051] [Ashless dispersant] The lubricating oil composition of one embodiment of the present invention may further contain an ashless dispersant from the viewpoint of improving dispersibility. The ashless dispersants may be used alone or in combination of two or more. The ashless dispersant used in one embodiment of the present invention is preferably an alkenyl succinimide, and examples thereof include an alkenyl succinic acid bisimide represented by the following general formula (f-1) and an alkenyl succinic acid monoimide represented by the following general formula (f-2).

[0052] [ka]

[0053] In the above general formulas (f-1) and (f-2), R f1 , R f2 and R f3 are each independently an alkenyl group having a mass average molecular weight (Mw) of 500 to 3000 (preferably 900 to 2500). R f1 , R f2 and R f3 Examples of the alkenyl group that can be selected as include a polybutenyl group, a polyisobutenyl group, an ethylene-propylene copolymer, and the like. Among these, a polybutenyl group or a polyisobutenyl group is preferred. A f1 , A f2 and A f3 are each independently an alkylene group having 2 to 5 carbon atoms. x1 is an integer of 0 to 10, preferably an integer of 1 to 4, and more preferably 2 or 3. x2 is an integer of 1 to 10, preferably an integer of 2 to 5, and more preferably 3 or 4.

[0054] The compound represented by the general formula (f-1) or (f-2) may be a modified alkenyl succinimide that is reacted with one or more compounds selected from the group consisting of boron compounds, alcohols, aldehydes, ketones, alkylphenols, cyclic carbonates, epoxy compounds, and organic acids.

[0055] [Rust inhibitor] The lubricating oil composition of one embodiment of the present invention may further contain a rust inhibitor. The rust inhibitor may be used alone or in combination of two or more kinds. Examples of the rust inhibitor used in one embodiment of the present invention include fatty acids, alkenyl succinic acid half esters, fatty acid soaps, alkyl sulfonates, polyhydric alcohol fatty acid esters, fatty acid amines, oxidized paraffins, and alkyl polyoxyethylene ethers.

[0056] [Antifoaming agent] The lubricating oil composition of one embodiment of the present invention may further contain an antifoaming agent. The antifoaming agents may be used alone or in combination of two or more. Examples of the defoaming agent used in one embodiment of the present invention include alkylsilicone-based defoaming agents, fluorosilicone-based defoaming agents, and fluoroalkyl ether-based defoaming agents.

[0057] <Method of manufacturing lubricating oil composition> There are no particular limitations on the method for producing the lubricating oil composition of one embodiment of the present invention, but from the viewpoint of productivity, it is preferred that the method comprises a step of blending, as necessary, components (B) and (C) and other lubricating oil additives into base oil (A).

[0058] [Properties of lubricating oil composition] The kinematic viscosity at 40°C of the lubricating oil composition of one embodiment of the present invention is preferably 50.0 mmHg, from the viewpoint of providing a lubricating oil composition with better fuel economy. 2 / s or less, preferably 47.0 mm 2 / s or less, more preferably 45.0 mm 2 / s or less, and preferably 5.0 mm 2 / s or more, preferably 10.0 mm 2 / s or more, more preferably 15.0 mm 2 / s or more, and even more preferably 20.0 mm 2 / s or more.

[0059] The kinematic viscosity at 100°C of the lubricating oil composition of one embodiment of the present invention is preferably 15.0 mmHg, from the viewpoint of providing a lubricating oil composition with improved fuel economy. 2 / s or less, preferably 13.0 mm 2 / s or less, more preferably 11.0 mm 2 / s or less, and preferably 3.0 mm 2 / s or more, preferably 4.0 mm 2 / s or more, more preferably 5.0 mm 2 / s or more.

[0060] The viscosity index of the lubricating oil composition of one embodiment of the present invention is preferably 130 or more, more preferably 140 or more, more preferably 150 or more, even more preferably 160 or more, still more preferably 170 or more, and particularly preferably 180 or more.

[0061] The viscosity grade of the lubricating oil composition of one embodiment of the present invention may be 0W-20 to 0W-30 according to the classification according to SAE J300:2015.

[0062] When the lubricating oil composition of one embodiment of the present invention has a viscosity grade of 0W-20 according to SAE J300:2015, the kinematic viscosity of the lubricating oil composition at 40°C is preferably 40.0 mmHg, from the viewpoint of providing a lubricating oil composition with improved fuel economy. 2 / s or less, preferably 37.0 mm 2 / s or less, more preferably 35.0 mm 2 / s or less, and preferably 22.0 mm 2 / s or more, preferably 25.0 mm 2 / s or more, more preferably 27.0 mm 2 / s or more.

[0063] When the lubricating oil composition of one embodiment of the present invention has a viscosity grade of 0W-20 according to SAE J300:2015, the kinematic viscosity of the lubricating oil composition at 100°C is preferably 8.0 mmHg, from the viewpoint of providing a lubricating oil composition with improved fuel economy. 2 / s or less, preferably 7.7 mm 2 / s or less, more preferably 7.5 mm 2 / s or less, and preferably 5.5 mm 2 / s or more, preferably 6.0 mm 2 / s or more, more preferably 6.5 mm 2 / s or more.

[0064] When the lubricating oil composition of one embodiment of the present invention has a viscosity grade of 0W-30 according to SAE J300:2015, the kinematic viscosity of the lubricating oil composition at 40°C is preferably 45.0 mmHg, from the viewpoint of providing a lubricating oil composition with better fuel economy. 2 / s or less, preferably 44.0 mm 2 / s or less, and preferably 25.0 mm 2 / s or more, preferably 30.0 mm 2 / s or more, more preferably 35.0 mm 2 / s or more, and even more preferably 40.0 mm 2 / s or more.

[0065] When the lubricating oil composition of one embodiment of the present invention has a viscosity grade of 0W-30 according to SAE J300:2015, the kinematic viscosity of the lubricating oil composition at 100°C is preferably 10.0 mmHg, from the viewpoint of providing a lubricating oil composition with improved fuel economy. 2 / s or less, preferably 9.8 mm 2 / s or less, and preferably 6.0 mm 2 / s or more, preferably 7.0 mm 2 / s or more, more preferably 8.0 mm 2 / s or more, and even more preferably 9.0 mm 2 / s or more.

[0066] The HTHS viscosity at 150°C of the lubricating oil composition of one embodiment of the present invention is preferably 2.5 mPa·s or more, and more preferably 2.6 mPa·s or more, from the viewpoint of improving oil film retention in high-temperature environments and providing a lubricating oil composition with excellent wear resistance; and from the viewpoint of providing a lubricating oil composition with good fuel economy in high-temperature environments and suitable for use in high-pressure environments, the HTHS viscosity is preferably 3.7 mPa·s or less, more preferably 3.5 mPa·s or less, even more preferably 3.4 mPa·s or less, still more preferably 3.3 mPa·s or less, and particularly preferably 3.2 mPa·s or less. In this specification, the HTHS viscosity at 150°C means a value measured at 150°C in accordance with ASTM D4683.

[0067] For the lubricating oil composition of one embodiment of the present invention, the residual oil percentage measured and calculated based on the method described in the Examples below is preferably 25.0% by mass or more, more preferably 26.0% by mass or more, even more preferably 27.0% by mass or more, and still more preferably 28.0% by mass or more, from the viewpoint of providing a lubricating oil composition that maintains good fluidity and is highly effective in suppressing deposit formation even when used in a high-temperature and / or high-pressure environment.

[0068] The SRV friction coefficient of the lubricating oil composition of one embodiment of the present invention, measured according to the method described in the Examples below, is preferably 0.08 or less, more preferably 0.07 or less, even more preferably 0.06 or less, and still more preferably 0.05 or less.

[0069] The lubricating oil composition of one embodiment of the present invention preferably has a score of 7.0 or more, more preferably 7.5 or more, even more preferably 8.0 or more, and still more preferably 8.5 or more in a hot tube test carried out in accordance with JPI-5S-55-99. The specific procedures and conditions for the hot tube test are as described in the Examples section below.

[0070] [Uses of lubricating oil composition] The lubricating oil composition of one embodiment of the present invention is excellent in the effect of suppressing deposit formation, detergency and stability, and fuel economy, regardless of the environment in which it is used. Therefore, the lubricating oil composition of one embodiment of the present invention can be suitably used, for example, to lubricate internal combustion engines. Therefore, the lubricating oil composition of one embodiment of the present invention can be applied to various devices that can exhibit the above-mentioned properties, but can also be suitably used for lubricating parts in internal combustion engines. It can be particularly suitable for lubricating parts in diesel engines, among other internal combustion engines. It can also be suitably used for lubricating parts in turbochargers equipped with an EGR system that re-intakes and recirculates a portion of the exhaust gas.

[0071] Such internal combustion engines are prone to high temperature and / or high pressure environments, which increase the evaporation rate of the lubricating oil composition, reducing its fluidity and making it susceptible to deposit formation. At the same time, problems such as reduced detergency and stability and reduced fuel economy are also likely to arise. In response to these problems, the lubricating oil composition of one embodiment of the present invention has excellent deposit suppression effects, detergency and stability, and fuel economy, regardless of the usage environment, and can therefore be suitably used for lubricating internal combustion engines, which are prone to such high temperature and / or high pressure environments.

[0072] Furthermore, in consideration of the above-mentioned properties of the lubricating oil composition of one embodiment of the present invention, the present invention can also provide the following [I] and [II]. [I] An internal combustion engine filled with the lubricating oil composition according to one embodiment of the present invention. [II] A method for lubricating an internal combustion engine, in which the lubricating oil composition according to one embodiment of the present invention is applied to the internal combustion engine. Examples of the internal combustion engines described in [I] and [II] above include diesel engines and superchargers equipped with an EGR system that re-intakes and recirculates part of the exhaust gas.

[0073] As described above, the present invention discloses the following aspects. [1] A base oil (A) and a metal-based detergent (B), The content of heavy fraction (Hf) having a carbon number of 32 or more in component (A) is 14.0 mass% or more based on the total amount of component (A), Component (B) contains an overbased calcium salicylate (B1) having a base number of 100 mg KOH / g or more, The content of component (B1) in component (B) is 35.0 mass% or more based on the total amount of component (B). Lubricating oil composition. [2] The lubricating oil composition according to the above item [1], wherein the ratio of the content of light fraction (Lf) having 21 or less carbon atoms to the content of heavy fraction (Hf) having 32 or more carbon atoms in component (A), [(Lf) / (Hf)], is 0.05 or more by mass. [3] The lubricating oil composition according to the above [1] or [2], wherein the content of light fraction (Lf) having 21 or less carbon atoms in component (A) is 1.0 to 20.0 mass% based on the total amount of component (A). [4] The lubricating oil composition according to any one of the above [1] to [3], wherein the content of component (B1) in terms of calcium atoms is 0.01 to 0.80 mass% based on the total amount of the lubricating oil composition. [5] The lubricating oil composition according to any one of the above [1] to [4], wherein the content of component (B) in terms of metal atoms is 0.01 to 1.00 mass% based on the total amount of the lubricating oil composition. [6] The lubricating oil composition according to any one of the above [1] to [5], further comprising a viscosity index improver (C). [7] The kinematic viscosity of the lubricating oil composition at 40°C is 45.0 mm 2 The lubricating oil composition according to any one of the above [1] to [6], wherein the viscosity is 1 / s or less. [8] The lubricating oil composition according to any one of the above [1] to [7], wherein the viscosity index of the lubricating oil composition is 130 or more. [9] The lubricating oil composition according to any one of the above [1] to [8], wherein the lubricating oil composition has an HTHS viscosity at 150°C of 2.5 mPa·s or more.

[10] The lubricating oil composition according to any one of [1] to [9] above, wherein the viscosity grade of the lubricating oil composition is 0W-20 to 0W-30 according to the classification according to SAE J300:2015.

[11] The lubricating oil composition according to any one of the above [1] to

[10] , which is used in a diesel engine.

[12] An internal combustion engine filled with the lubricating oil composition according to any one of the above [1] to

[11] .

[13] The internal combustion engine according to

[12] above, wherein the internal combustion engine is a diesel engine.

[14] A method for lubricating an internal combustion engine, comprising applying the lubricating oil composition according to any one of the above [1] to

[11] to the internal combustion engine.

[15] The lubrication method for an internal combustion engine according to

[14] above, wherein the internal combustion engine is a diesel engine. [Example]

[0074] The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples. The methods for measuring various physical properties are as follows.

[0075] (1) Kinematic viscosity and viscosity index Measurements and calculations were made in accordance with JIS K2283:2000. (2) Ring analysis Measurement was performed in accordance with ASTM D-3238 ring analysis (ndM method). (3) Content of each carbon number component that makes up the base oil Using a gas chromatograph (manufactured by Shimadzu Corporation, product name "GC-2014") under the following measurement conditions, the content of components with each carbon number constituting the base oil was calculated by comparing with a chromatogram of a standard sample. Column size: 4mm x 3mm x 1.5mm (SUS) Column packing material: Silicone OV-1 1.5% Shinwasorb-S 60 / 80 Standard samples: n-hexane, n-paraffin: C8 to C36 standard samples Gas: He gas, 50 mL / min (4) Base number (perchloric acid method) Measurements were performed in accordance with "9. Potentiometric titration method (base number, perchloric acid method)" of JIS K2501 "Petroleum products and lubricants - Neutralization number test method." (5) Calcium atom (Ca) content Measurements were performed in accordance with JPI-5S-38-92. (6) Weight average molecular weight (Mw) Measurement was carried out using a gel permeation chromatograph (Agilent Technologies, "1260 Model HPLC") under the following conditions, and the values ​​measured were converted into standard polystyrene values. (Measurement conditions) Column: Two Shodex LF404 columns connected in series. Column temperature: 35℃ Developing solvent: chloroform ·Flow rate: 0.3mL / min (7)HTHS viscosity (150℃) Measured at 150°C in accordance with ASTM D4683.

[0076] Examples 1 to 6, Comparative Examples 1 to 6 Lubricating oil compositions were prepared by adding and mixing the base oil and various additives in the amounts shown in Tables 1 and 2. In the examples and comparative examples shown in Table 1, the viscosity characteristics of the lubricating oil compositions were adjusted to correspond to 0W-20 in the SAE J300:2015 classification. In the examples and comparative examples shown in Table 2, the viscosity characteristics of the lubricating oil compositions were adjusted to correspond to 0W-30 in the SAE J300:2015 classification. The details of each component used in preparing the lubricating oil composition are as follows:

[0077] <Component (A): Base oil> "Base oil (a-1)": Base oil classified as Group III of the API base oil category, kinematic viscosity at 40°C = 7.1 mm 2 / s, viscosity index=109. "Base oil (a-2)": Base oil classified as Group III of the API base oil category, kinematic viscosity at 40°C = 18.4 mm 2 / s, viscosity index=125. "Base oil (a-3)": Base oil classified as Group III of the API base oil category, kinematic viscosity at 40°C = 32.7 mm 2 / s, viscosity index=132. "Base oil (a-4)": Base oil classified as Group III of the API base oil category, kinematic viscosity at 40°C = 43.8 mm 2 / s, viscosity index=143.

[0078] <Component (B): Metallic detergent> "Overbased calcium salicylate (1)": calcium salicylate with a base number of 356 mg KOH / g, calcium content of 12.5% ​​by mass, corresponds to component (B1). "Overbased calcium salicylate (2)": calcium salicylate with a base number of 228 mg KOH / g, calcium content of 7.9% by mass, corresponds to component (B1). "Neutral Ca salicylate": Calcium salicylate with a base number of 67.4 mg KOH / g and a Ca content of 2.32% by mass. "Overbased Ca sulfonate": Calcium sulfonate with a base number of 305 mg KOH / g and a Ca content of 11.7% by mass. "Overbased Ca phenate": Calcium phenate with a base number of 152 mg KOH / g and a Ca content of 5.49% by mass. "Neutral Ca sulfonate": Calcium sulfonate with a base number of 17 mg KOH / g and a Ca content of 2.4% by mass.

[0079] <Component (C): Viscosity index improver> "PMA": Non-dispersed polymethacrylate with Mw=400,000. - "Comb-shaped PMA": Polymethacrylate-based comb-shaped polymer with Mw=310,000. - "Dispersed OCP": Dispersed polyolefin copolymer with Mw=120,000.

[0080] <Other additives> · "Additive Mix": An additive mix containing antioxidants, ashless dispersants, friction modifiers, antifoam agents, and metal deactivators.

[0081] The kinematic viscosity at 40°C and 100°C, viscosity index, and HTHS viscosity at 150°C of the prepared lubricating oil compositions were measured or calculated, and the following various measurements and tests were also carried out. The results are shown in Tables 1 and 2.

[0082] (1)Residual oil rate measurement Using a container and constant temperature air bath used in the lubricating oil thermal stability test specified in JIS K2540, 1 g of sample oil was placed in the container, and heated at 200°C for 20 hours while air was flowing into the constant temperature air bath at a flow rate of 10 L / hr. The amount of residual oil in the sample oil after heating was measured. The residual oil rate was then calculated using the following formula. Residual oil rate [%] = Residual amount of sample oil after heating [g] / Mass of sample oil before heating (= 1g) x 100 The higher the residual oil ratio, the better the fluidity in high-temperature environments and the greater the deposit-suppressing effect of the lubricating oil composition. In this example, a residual oil ratio of 25.0% or more was determined to be a lubricating oil composition with good fluidity in high-temperature environments and a high deposit-suppressing effect.

[0083] (2) SRV test The friction coefficient of each lubricating oil composition prepared was measured using an SRV tester (manufactured by Optimol) under the following conditions. The lower the friction coefficient, the better the friction-reducing effect, and therefore the better the lubricating oil composition's fuel-saving properties. In this example, a friction coefficient of 0.08 or less was determined to be a lubricating oil composition with good fuel-saving properties. Test piece: (a) Disc: SUJ-2 material, (b) Cylinder: SUJ-2 material ·Amplitude: 1.5mm Frequency: 50Hz Load: 400N ·Temperature: 40℃

[0084] (3) Hot tube test A hot tube test was conducted in accordance with JPI-5S-55-99. Specifically, the lubricating oil compositions prepared in the Examples and Comparative Examples were flowed into a glass tube with an inner diameter of 2 mm at a rate of 0.3 mL / hour and air at a rate of 10 mL / min for 16 hours while the temperature of the glass tube was maintained at 290°C. After the hot tube test, the lacquer adhering to the glass tube was compared with a color sample, and the degree of discoloration inside the glass tube was scored on a 21-point scale in 0.5 increments, with 10 points for colorless and transparent and 0 points for black. The higher the score, the better the lubricating oil composition's high-temperature detergency and high-temperature stability. In this example, a score of 7.0 or higher was considered to be a lubricating oil composition with good high-temperature detergency.

[0085] [Table 1]

[0086] [Table 2]

[0087] From Tables 1 and 2, it can be seen that the lubricating oil compositions prepared in Examples 1 to 6 have excellent fluidity even in high-temperature environments and are highly effective in suppressing deposit formation. Furthermore, they also have good viscosity characteristics, such as kinematic viscosity at 40°C, and low friction coefficients measured in the SRV test, which means they are also excellent in fuel economy. Furthermore, they received high scores of 8.5 or higher in the hot tube test, and their detergency and stability in high-temperature environments were also good. On the other hand, the lubricating oil compositions prepared in Comparative Examples 1 and 4 have poor fluidity in high-temperature environments, which is thought to result in insufficient suppression of deposit formation. Furthermore, the lubricating oil compositions prepared in Comparative Examples 2 and 5 have a higher kinematic viscosity at 40°C than the Examples in the same table, resulting in problems with fuel economy and low scores in the hot tube test, which in turn result in problems with detergency and stability in high-temperature environments. Furthermore, the lubricating oil compositions prepared in Comparative Examples 3 and 6 also had high friction coefficients measured in the SRV test, which resulted in problems with fuel economy and low scores in the hot tube test, which in turn resulted in problems with detergency and stability in high-temperature environments.

Claims

1. A base oil (A) and a metal-based detergent (B), The content of heavy fraction (Hf) having a carbon number of 32 or more in component (A) is 14.0 mass% or more based on the total amount of component (A), Component (B) contains an overbased calcium salicylate (B1) having a base number of 100 mg KOH / g or more, The content of component (B1) in component (B) is 35.0 mass% or more based on the total amount of component (B). Lubricating oil composition.

2. 2. The lubricating oil composition according to claim 1, wherein the content ratio [(Lf) / (Hf)] of the light fraction (Lf) having 21 or less carbon atoms to the heavy fraction (Hf) having 32 or more carbon atoms in component (A) is, in mass ratio, 0.05 or more.

3. The lubricating oil composition according to claim 1 or 2, wherein the content of light fraction (Lf) having 21 or less carbon atoms in component (A) is 1.0 to 20.0 mass% based on the total amount of component (A).

4. 3. The lubricating oil composition according to claim 1, wherein the content of component (B1) in terms of calcium atoms is 0.01 to 0.80 mass % based on the total amount of the lubricating oil composition.

5. 3. The lubricating oil composition according to claim 1, wherein the content of component (B) in terms of metal atoms is 0.01 to 1.00 mass % based on the total amount of the lubricating oil composition.

6. The lubricating oil composition according to claim 1 or 2, further comprising a viscosity index improver (C).

7. The lubricating oil composition has a kinetic viscosity of 45.0 mm at 40°C. ２ The lubricating oil composition according to claim 1 or 2, wherein the viscosity is 0.05 to 1.0 MPa.

8. 3. The lubricating oil composition according to claim 1, wherein the lubricating oil composition has a viscosity index of 130 or greater.

9. 3. The lubricating oil composition according to claim 1, wherein the lubricating oil composition has a HTHS viscosity at 150° C. of 2.5 mPa·s or more.

10. The lubricating oil composition according to claim 1 or 2, wherein the viscosity grade of the lubricating oil composition is 0W-20 to 0W-30 according to the classification according to SAE J300:2015.

11. The lubricating oil composition according to claim 1 or 2, which is used in a diesel engine.

12. 3. An internal combustion engine filled with the lubricating oil composition according to claim 1 or 2.

13. 13. The internal combustion engine of claim 12, wherein the internal combustion engine is a diesel engine.

14. A method for lubricating an internal combustion engine, comprising applying the lubricating oil composition according to claim 1 or 2 to the internal combustion engine.

15. 15. The method of claim 14, wherein the internal combustion engine is a diesel engine.