JP6591907B2 - Lubricating oil composition for internal combustion engines - Google Patents

Description

  The present invention relates to a lubricating oil composition for an internal combustion engine.

In recent years, lubricating oil (engine oil) used for internal combustion engines such as automobile engines has been required to improve fuel efficiency in order to reduce CO ₂ emissions from automobiles. As a method for improving the fuel economy of engine oil, there is a reduction in the viscosity of the oil. However, if the viscosity is excessively reduced, the engine may be worn. Therefore, a method for improving fuel economy by adding a friction modifier has been studied instead.

  For example, Patent Document 1 discloses a diesel engine oil composition containing a predetermined mineral oil base oil and various additives such as a molybdenum dithiocarbamate friction modifier for the purpose of improving fuel efficiency by reducing friction. Yes.

JP 2002-220597 A

  An object of this invention is to provide the lubricating oil composition for internal combustion engines which is excellent in fuel-saving property and the corrosion prevention property with respect to copper.

  The present invention is based on the lubricating base oil and the total amount of the lubricating oil composition, 0.03% by mass or more of an organic molybdenum friction modifier in terms of molybdenum element, and 0.03% by mass or more in terms of metal element, There is provided a lubricating oil composition for an internal combustion engine, comprising at least one metal-based detergent selected from the group consisting of alkali metal phenates and alkaline earth metal phenates.

  The base number of the metal detergent is preferably 200 mgKOH / g or more. In this case, the lubricating oil composition is also excellent in terms of corrosion resistance to lead.

  The lubricating oil composition is suitably used as a diesel engine oil.

  ADVANTAGE OF THE INVENTION According to this invention, the lubricating oil composition for internal combustion engines excellent in fuel-saving property and the corrosion prevention property with respect to copper can be provided.

  The lubricating oil composition according to this embodiment is selected from the group consisting of a lubricating base oil, an organic molybdenum friction modifier (hereinafter also referred to as “component (A)”), an alkali metal phenate, and an alkaline earth metal phenate. And at least one metallic detergent (hereinafter also referred to as “component (B)”). The lubricating oil composition according to this embodiment is suitable as a lubricating oil composition for internal combustion engines.

  The lubricating base oil is not particularly limited, and may be a base oil used for ordinary lubricating oil. Specifically, the lubricant base oil includes a mineral base oil, a synthetic base oil, or a mixture of both.

  As mineral base oils, lubricating oil fractions obtained by subjecting crude oil to atmospheric distillation and reduced pressure distillation are subjected to solvent deburring, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, hydrorefining, sulfuric acid Examples include paraffinic and naphthenic mineral oil base oils, normal paraffins, isoparaffins, and the like, which are purified by combining purification treatments such as washing and clay treatment alone or in combination of two or more. These mineral oil base oils may be used singly or in combination of two or more at any ratio.

Preferred mineral base oils include the following base oils.
(1) Distilled oil obtained by atmospheric distillation of paraffin-based crude oil and / or mixed-base crude oil (2) Vacuum-distilled distilled oil (WVGO) of atmospheric distillation residue oil of paraffin-based crude oil and / or mixed-base crude oil )
(3) Wax obtained by a lubricant dewaxing step and / or a Fischer-Tropsch wax produced by a GTL process or the like (4) One or more mixed oils selected from the above (1) to (3) Mild hydrocracking oil (MHC)
(5) Mixed oil of two or more oils selected from the above (1) to (4) (6) Detachment of (1), (2), (3), (4) or (5) Oil (DAO)
(7) Mild hydrocracking treatment oil (MHC) of (6) above
(8) A mixed oil or the like of two or more kinds of oils selected from the above (1) to (7) is used as a raw oil, and this raw oil and / or a lubricating oil fraction recovered from this raw oil is usually used. Oil obtained by refining by the refining method and recovering the lubricating oil fraction

Here, the normal refining method is not particularly limited, and a refining method used in base oil production can be arbitrarily employed. Examples of normal purification methods include the following purification methods.
(A) Hydrorefining such as hydrocracking, hydrofinishing, etc. (b) Solvent refining such as extraction of furfural solvent (c) Dewaxing such as solvent dewaxing, catalytic dewaxing, etc. (d) White clay with acid clay, activated clay Purification (e) Chemical (acid or alkali) purification such as sulfuric acid washing and caustic soda washing These purification methods can be used singly or in combination of two or more and in any order.

  Synthetic base oils include poly α-olefins or hydrides thereof, isobutene oligomers or hydrides thereof, isoparaffins, alkylbenzenes, alkylnaphthalenes, diesters (ditridecyl glutarate, di-2-ethylhexyl adipate, di-2-ethylhexyl azease). Rate, diisodecyl adipate, ditridecyl adipate, di-2-ethylhexyl sebacate, etc.), polyol ester (trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol 2-ethylhexanoate, pentaerythritol pelargonate, etc.), Polyoxyalkylene glycol, dialkyl diphenyl ether, polyphenyl ether and the like can be mentioned, among which poly α-olefin is preferable. Examples of the poly α-olefin include oligomers or co-oligomers (1-octene oligomer, decene oligomer, ethylene-propylene co-oligomer, etc.) of α-olefin having 2 to 32 carbon atoms, preferably 6 to 16 carbon atoms, and those. A hydride is mentioned. These synthetic base oils may be used individually by 1 type, and may be used combining 2 or more types by arbitrary ratios.

The kinematic viscosity at 40 ° C. of the lubricating base oil is preferably 6.0 mm ² / s or more, more preferably from the viewpoint of sufficient oil film formation, excellent lubricity, and smaller evaporation loss under high temperature conditions. 12.0 mm ² / s or more, more preferably 15.0 mm ² / s or more. The kinematic viscosity at 100 ° C. of the lubricating base oil is preferably 60.0 mm ² / s or less, more preferably 50.0 mm ² / s or less, and more preferably 50.0 mm ² / s or less, from the viewpoint of improving low-temperature viscosity characteristics and further improving fuel economy. Preferably it is 40.0 mm < ² > / s or less.

The kinematic viscosity at 100 ° C. of the lubricating base oil is preferably 2.0 mm ² / s or more, more preferably from the viewpoint of sufficient oil film formation, excellent lubricity, and smaller evaporation loss under high temperature conditions. It is 3.0 mm ² / s or more, more preferably 3.5 mm ² / s or more. The kinematic viscosity at 100 ° C. of the lubricating base oil is preferably 8.0 mm ² / s or less, more preferably 7.0 mm ² / s or less, and more preferably 7.0 mm ² / s or less, from the viewpoint of improving low temperature viscosity characteristics and further improving fuel economy. Preferably it is 6.0 mm < ² > / s or less.

  The viscosity index of the lubricating base oil is preferably 100 or more, more preferably 110 or more, from the viewpoint that viscosity-temperature characteristics, thermal / oxidation stability, and volatilization prevention properties are improved and the friction coefficient can be further reduced. Preferably it is 120 or more. The viscosity index of the lubricating base oil is preferably 180 or less, more preferably 170 or less, and still more preferably 160 or less, from the viewpoint of excellent low-temperature viscosity characteristics.

  The kinematic viscosity and viscosity index in the present invention mean kinematic viscosity and viscosity index measured in accordance with JIS K2283: 2000, respectively.

  The content of the lubricating base oil may be, for example, 50% by mass or more, 70% by mass or more, or 90% by mass or more based on the total amount of the lubricating oil composition.

  Examples of the (A) organic molybdenum friction modifier include molybdenum dithiocarbamate (MoDTC), molybdenum dithiophosphate (MoDTP), and a molybdenum-amine complex. Among these, molybdenum dithiocarbamate (MoDTC) is preferable.

  Examples of molybdenum dithiocarbamate (MoDTC) include a compound represented by the following formula (1).

In formula (1), R ^{1 to} R ⁴ may be the same as or different from each other, and each represents a linear or branched alkyl group having 4 to 18 carbon atoms, or a linear or branched alkenyl group. And X ^{1 to} X ⁴ each independently represent an oxygen atom or a sulfur atom. However, the ratio of oxygen atom to sulfur atom in X ^{1 to} X ⁴ is 1/3 to 3/1 (that is, at least one of X ^{1 to} X ⁴ is an oxygen atom, and X ^{1 to} X ⁴ At least one of them is a sulfur atom).

R ^{1 to} R ⁴ are preferably a linear or branched alkyl group having 4 to 18 carbon atoms, and particularly preferably a branched alkyl group having 8 to 14 carbon atoms. Specific examples of such a group include a butyl group, a 2-ethylhexyl group, an isotridecyl group, and a stearyl group.

  The component (A) may be one of the above organic molybdenum friction modifiers, or a mixture of two or more.

  The content of the component (A) is preferably 0.03% by mass or more, more preferably 0.035% by mass or more, in terms of molybdenum element, based on the total amount of the lubricating oil composition, from the viewpoint of further improving fuel economy. More preferably, it is 0.04 mass% or more. The content of the component (A) is preferably 0.08% by mass or less, more preferably 0.08% by mass or less, in terms of molybdenum element, based on the total amount of the lubricating oil composition, from the viewpoint of further excellent corrosion resistance against copper and long-term storage stability. Is 0.06% by mass or less, more preferably 0.05% by mass or less, and particularly preferably 0.045% by mass or less. The content of the component (A) is preferably from the viewpoint of excellent fuel economy, corrosion resistance to copper, and long-term storage stability, preferably in terms of molybdenum element, based on the total amount of the lubricating oil composition. 03-0.08 mass%, 0.03-0.06 mass%, 0.03-0.05 mass%, 0.03-0.045 mass%, 0.035-0.08 mass%, 0.0. 035 to 0.06% by mass, 0.035 to 0.05% by mass, 0.035 to 0.045% by mass, 0.04 to 0.08% by mass, 0.04 to 0.06% by mass, 0. It is 04-0.05 mass%, or 0.04-0.045 mass%. The content of component (A) (molybdenum element equivalent) can be measured by ICP elemental analysis.

  (B) As an alkali metal phenate or alkaline earth metal phenate, an alkylphenol having at least one linear or branched alkyl group having 4 to 30 carbon atoms, an alkylphenol sulfide obtained by reacting this alkylphenol with sulfur, Or the alkali metal salt or alkaline-earth metal salt of the Mannich reaction product of the alkylphenol obtained by making formaldehyde react with this alkylphenol can be mentioned. Carbon number of the said linear or branched alkyl group becomes like this. Preferably it is 6-18. The alkali metal may be sodium, potassium or the like. The alkaline earth metal may be magnesium, calcium, barium or the like, preferably magnesium or calcium, more preferably calcium. The component (B) may be one of these alkali metal phenates or alkaline earth metal phenates or a mixture of two or more.

  The content of the component (B) is preferably 0.03% by mass or more, more preferably 0.04% by mass in terms of metal elements, based on the total amount of the lubricating oil composition, from the viewpoint of further excellent corrosion resistance to copper. % Or more, more preferably 0.05 mass% or more. The content of the component (B) is preferably 0.25% by mass or less, more preferably 0.2% by mass or less, in terms of metal elements, based on the total amount of the lubricating oil composition, from the viewpoint of further improving fuel economy. More preferably, it is 0.15 mass% or less, Most preferably, it is 0.1 mass% or less. The content of the component (B) is preferably 0.03 to metal element in terms of the total amount of the lubricating oil composition from the viewpoint of achieving both higher levels of corrosion prevention and fuel economy for copper. 0.25 mass%, 0.03-0.2 mass%, 0.03-0.15 mass%, 0.03-0.1 mass%, 0.04-0.25 mass%, 0.04- 0.2% by mass, 0.04 to 0.15% by mass, 0.04 to 0.1% by mass, 0.05 to 0.25% by mass, 0.05 to 0.2% by mass, 0.05 to It is 0.15 mass%, or 0.05-0.1 mass%. The content of component (B) (metal element equivalent value) can be measured by ICP elemental analysis.

  The base number of the component (B) is preferably 50 mgKOH / g or more, more preferably 100 mgKOH / g or more, still more preferably 150 mgKOH / g or more, particularly preferably 200 mgKOH / g or more from the viewpoint of excellent corrosion resistance to lead. is there. The base number of the component (B) is preferably 500 mgKOH / g or less, more preferably 400 mgKOH / g or less, and still more preferably 300 mgKOH / g, from the viewpoint that the effect of reducing friction by the organic molybdenum friction modifier is more suitably exhibited. It is as follows. The base number in the present invention is 9. JIS K2501: 2003 9. The base number measured by the perchloric acid method.

  The lubricating oil composition may further contain other additives. Other additives include metallic detergents other than component (B), ashless dispersant, viscosity index improver, antiwear agent, antioxidant, antifoaming agent, pour point depressant, corrosion inhibitor, rust inhibitor Agents, demulsifiers, metal deactivators and the like.

  Examples of the metal detergent other than the component (B) include alkali metal salicylates, alkaline earth metal salicylates, alkali metal sulfonates, and alkaline earth metal sulfonates. The alkali metal may be sodium, potassium or the like. The alkaline earth metal may be magnesium, calcium, barium or the like, preferably magnesium or calcium, more preferably calcium. The lubricating oil composition may contain these metallic detergents alone or in any combination of two or more.

  Examples of the ashless dispersant include nitrogen-containing compounds having at least one linear or branched alkyl group or alkenyl group having 40 to 400 carbon atoms in the molecule, or derivatives thereof. The carbon number of the alkyl group or alkenyl group of the ashless dispersant is preferably 40 to 400, more preferably 60 to 350. When the carbon number of the alkyl group or alkenyl group is 40 or more, the solubility of the ashless dispersant in the lubricating base oil tends to be improved. On the other hand, when the carbon number of the alkyl group or alkenyl group is 400 or less, The low temperature fluidity of the lubricating oil composition tends to be improved. Specific examples of preferred alkyl groups or alkenyl groups include branched alkyl groups and branched alkenyl groups derived from olefin oligomers such as propylene, 1-butene, and isobutylene, or ethylene-propylene co-oligomers. Can be mentioned.

  As the ashless dispersant, specifically, at least one nitrogen-containing compound selected from the group consisting of succinimide, alkenyl succinimide, benzylamine and polyamine, or this nitrogen-containing compound is used as carboxylic acid, phosphoric acid, boron. Examples include modified products modified with compounds and the like.

  Examples of the succinimide include a so-called mono-type succinimide in which succinic anhydride is added to one end of the polyamine, or a so-called bis-type succinimide in which succinic anhydride is added to both ends of the polyamine.

Specific examples of benzylamine include compounds represented by the following formula (2).
^{_{R 5 -Ph-CH 2 NH- (}} CH 2 CH 2 NH) p -H (2)
In Formula (2), R ⁵ represents an alkyl group or alkenyl group having 40 to 400 carbon atoms, and preferably represents an alkyl group or alkenyl group having 60 to 350 carbon atoms. Ph represents a phenylene group, and p represents an integer of 1 to 5, preferably an integer of 2 to 4.

Specifically as a polyamine, the compound etc. which are represented by following formula (3) can be illustrated.
R ⁶ —NH— (CH ₂ CH ₂ NH) _q —H (3)
In formula (3), R ⁶ represents an alkyl group or alkenyl group having 40 to 400 carbon atoms, and preferably represents an alkyl group or alkenyl group having 60 to 350 carbon atoms. q represents an integer of 1 to 5, preferably an integer of 2 to 4.

  Examples of the modified products include polycarboxylic acids having 2 to 30 carbon atoms such as monocarboxylic acids having 1 to 30 carbon atoms (fatty acids, etc.), oxalic acid, phthalic acid, trimellitic acid, pyromellitic acid, etc. Alternatively, an oxygen-containing compound such as hydroxy (poly) alkylene carbonate is allowed to act to neutralize part or all of the remaining amino group and imino group, or an amidated modified compound, and a sulfur compound is allowed to act on the nitrogen-containing compound. And a boric acid modified compound obtained by modifying the above nitrogen-containing compound with a boron compound.

  For example, as a method for producing a boronated succinimide which is one of the boric acid-modified compounds, JP-A-42-8013, JP-A-42-8014, JP-A-51-52381, The publicly known method etc. which are indicated by JP, 51-130408, A, etc. are mentioned. Specifically, the boronated succinimide includes alcohols, organic solvents such as hexane and xylene, light lubricating base oil, polyamine, polyalkenyl succinic acid (anhydride), boric acid and boric acid ester. Or it can obtain by mixing boron compounds, such as a borate, and heat-processing on suitable conditions. In addition, the boron content in the boronated succinimide thus obtained may be 0.1 to 4.0% by mass.

  The ashless dispersant may be one of the above compounds or a mixture of two or more.

  When the lubricating oil composition contains an ashless dispersant, the content of the ashless dispersant is preferably 0.1% by mass or more, more preferably 2.5% by mass or more, based on the total amount of the lubricating oil composition. And more preferably 5% by mass or more. When the content of the ashless dispersant is 0.1% by mass or more, the friction reducing property tends to be improved. The content of the ashless dispersant is preferably 20% by mass or less, more preferably 10% by mass or less, based on the total amount of the lubricating oil composition. When the content of the ashless dispersant is 20% by mass or less, the low temperature fluidity of the lubricating oil composition tends to be sufficient. The content of the ashless dispersant is preferably 0.1 to 20% by mass, more preferably 1 to 10% by mass, based on the total amount of the lubricating oil composition.

  When using a boronated ashless dispersant such as the boronated succinimide, the content of the boronated ashless dispersant in the lubricating oil composition is 0.01 mass in terms of boron element based on the total amount of the lubricating oil composition. % Or more, preferably 0.02% by mass or more, more preferably 0.025% by mass or more. The content of the boronated ashless dispersant in the lubricating oil composition may be 0.15% by mass or less, preferably 0.1% by mass or less, in terms of boron element, based on the total amount of the lubricating oil composition. Preferably it is 0.05 mass% or less. The content of boronated ashless dispersant (in terms of boron element) can be measured by ICP elemental analysis.

  In the lubricating oil composition, it is preferable to use a boronated succinimide and a non-borated succinimide in combination as an ashless dispersant. The ratio of the content of the boronated succinimide to the content of the non-boronated succinimide is preferably 0.1, from the viewpoint of sufficient heat resistance and wear resistance effect by the boronated succinimide. Preferably it is 0.2 or more, More preferably, it is 0.3 or more. The ratio of the content of boronated succinimide to the content of non-borated succinimide is preferably 0.6 or less, more preferably 0.5 or less, and still more preferably 0.4, from the viewpoint of excellent cleanability. It is as follows.

  Examples of the viscosity index improver include a poly (meth) acrylate viscosity index improver, an olefin copolymer viscosity index improver, and a styrene-diene copolymer viscosity index improver. These viscosity index improvers may be either non-dispersed or dispersed, preferably non-dispersed. The viscosity index improver is preferably a poly (meth) acrylate viscosity index improver, more preferably a non-dispersed poly (meta), from the viewpoint of high viscosity index improvement effect and excellent viscosity-temperature characteristics and low temperature viscosity characteristics. ) Acrylate viscosity index improver.

  The pour point depressant may be, for example, poly (meth) acrylate, preferably poly (meth) acrylate having a weight average molecular weight of 10,000 to 300,000, more preferably 50,000 to 200,000.

  Antiwear agents include phosphorous acid esters (phosphites), phosphoric acid esters, and phosphorus-based antiwear agents such as amine salts, metal salts, and derivatives thereof, disulfides, polysulfides, sulfurized olefins, sulfurized fats and oils, etc. And sulfur-based antiwear agents.

  Examples of the antioxidant include ashless antioxidants such as phenols and amines, and metal antioxidants such as copper and molybdenum. Specifically, for example, as a phenol-based ashless antioxidant, 4,4′-methylenebis (2,6-di-tert-butylphenol), 4,4′-bis (2,6-di-tert- Butylphenol) and the like, and examples of amine-based ashless antioxidants include phenyl-α-naphthylamine, alkylphenyl-α-naphthylamine, dialkyldiphenylamine, and diphenylamine.

As the defoaming agent, for example, 100,000 mm kinematic viscosity at 25 ° C. is 1000 mm ² / s or more ² / s or less silicone oil, alkenylsuccinic acid derivatives, esters of polyhydroxy aliphatic alcohols and long-chain fatty acids, methyl salicylate And esters of o-hydroxybenzyl alcohol and the like.

  Examples of the corrosion inhibitor include benzotriazole, tolyltriazole, and imidazole compounds.

  Examples of the rust preventive include alkenyl succinic acid ester, polyhydric alcohol ester, petroleum sulfonate, alkylbenzene sulfonate, dinonylnaphthalene sulfonate, and the like.

  Examples of the demulsifier include polyalkylene glycol nonionic surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, and polyoxyethylene alkyl naphthyl ether.

  Examples of the metal deactivator include imidazoline, pyrimidine derivatives, benzotriazole or derivatives thereof.

  The content of other additives may be 0.01 to 20% by mass based on the total amount of the lubricating oil composition.

The kinematic viscosity at 40 ° C. of the lubricating base oil is preferably 6.0 mm ² / s or more, more preferably from the viewpoint of sufficient oil film formation, excellent lubricity, and smaller evaporation loss under high temperature conditions. 12.0 mm ² / s or more, more preferably 15.0 mm ² / s or more. The kinematic viscosity at 100 ° C. of the lubricating base oil is preferably 60.0 mm ² / s or less, more preferably 50.0 mm ² / s or less, and more preferably 50.0 mm ² / s or less, from the viewpoint of improving low-temperature viscosity characteristics and further improving fuel economy. Preferably it is 40.0 mm < ² > / s or less.

Kinematic viscosity at 100 ° C. of the lubricating oil composition, from the viewpoint of excellent lubricity, preferably 5.0 mm ² / s or more, more preferably 7.0 mm ² / s or more, more preferably 8.0 mm ² / s or more It is. Kinematic viscosity at 100 ° C. of the lubricating oil composition, to ensure low-temperature viscosity required, from the viewpoint of further improving the fuel economy, preferably 14.0 mm ² / s or less, more preferably 13.0 mm ² / s or less More preferably, it is 12.0 mm ² / s or less.

  The viscosity index of the lubricating oil composition is preferably 120 or more, more preferably 140 or more, further from the viewpoint of improving viscosity-temperature characteristics, thermal / oxidation stability, and volatilization prevention properties, and further reducing the friction coefficient. Preferably it is 150 or more. The viscosity index of the lubricating base oil is preferably 270 or less, more preferably 260 or less, and even more preferably 250 or less, from the viewpoint of excellent low-temperature viscosity characteristics.

  The molybdenum element content in the lubricating oil composition is preferably 0.03 mass% or more, more preferably 0.04 mass%, in terms of molybdenum element, based on the total amount of the lubricating oil composition, from the viewpoint of further improving fuel economy. % Or more. The molybdenum element content in the lubricating oil composition is preferably 0.08% by mass or less, more preferably 0.08% by mass or less in terms of molybdenum element, based on the total amount of the lubricating oil composition, from the viewpoint of excellent corrosion resistance against copper and long-term storage stability. Is 0.05% by mass or less, more preferably 0.045% by mass or less.

  The total content of alkali metals and alkaline earth metal elements in the lubricating oil composition is preferably 500 ppm by mass or more, more preferably 1000 ppm by mass or more, and even more preferably 1500 ppm by mass or more, based on the total amount of the lubricating oil composition. It is. The total content of alkali metals and alkaline earth metal elements in the lubricating oil composition is preferably 3500 ppm by mass or less, more preferably 3000 ppm by mass or less, and even more preferably 2600 ppm by mass or less. When the total content of alkali metal and alkaline earth metal element in the lubricating oil composition is 500 ppm by mass or more, long drain performance such as base number maintenance and high-temperature cleanability tends to be improved. On the other hand, when the total content of alkali metal and alkaline earth metal element in the lubricating oil composition is 3500 ppm by mass or less, the amount of sulfated ash produced is reduced, and the exhaust gas purification catalyst is less likely to be clogged, and the exhaust gas It tends to be able to maintain the purification performance of the aftertreatment device. The alkali metal and alkaline earth metal element content can be measured by ICP elemental analysis.

  The amount of sulfated ash in the lubricating oil composition is preferably 1.6% by mass or less, more preferably 1.3% by mass, based on the total amount of the lubricating oil composition, from the viewpoint of maintaining the purification performance of the exhaust gas aftertreatment device. More preferably, it is 1.1 mass% or less, Most preferably, it is 1.0 mass% or less. When the amount of sulfated ash in the lubricating oil composition is 1.6% by mass or less, the exhaust gas purification catalyst tends to be clogged. The sulfated ash in the present invention means the amount of sulfated ash measured by “5. Sulfated ash test method” of JIS K2272: 1998.

  The lubricating oil composition according to this embodiment is suitably used as a lubricating oil composition for internal combustion engines. Examples of the internal combustion engine include a gasoline engine, a diesel engine, an oxygen-containing compound-containing engine, a gas engine, and the like. The lubricating oil composition according to this embodiment is particularly preferably used as a diesel engine oil.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example, this invention is not limited to an Example.

Lubricating oil compositions having the compositions shown in Tables 1 and 2 were prepared using the base oils and additives shown below.
(Base oil)
Hydrorefined mineral oil (kinematic viscosity at 100 ° C .: 4.2 mm ² / s, viscosity index: 124)
(Additive)
A-1: Molybdenum dithiocarbamate (molybdenum element content: 10% by mass)
B-1: Calcium phenate (base number: 286 mg KOH / g, calcium element content: 10.2% by mass)
B-2: Calcium phenate (base number: 255 mg KOH / g, calcium element content: 9.25% by mass)
B-3: Calcium phenate (base number: 147 mg KOH / g, calcium element content: 5.3% by mass)
b-1: Calcium salicylate (base number: 173 mg KOH / g, calcium element content: 6.2% by mass)
b-2: Calcium sulfonate (base number: 425 mg KOH / g, calcium element content: 16.1% by mass)
C-1: (dispersed) polymethacrylate having a nitrogen-containing group (weight average molecular weight: 260000, SSI: 50)
C-2: Styrene diene copolymer (weight average molecular weight: 430000, SSI: 25)
D-1: Additive package containing ashless dispersant, zinc dialkyldithiophosphate, etc. (phosphorus element content: 0.9 mass%)

(Fuel saving)
About each lubricating oil composition of an Example , a reference example, and a comparative example, fuel-saving property was evaluated by the friction coefficient by a SRV test. When the friction coefficient of the SRV test under the conditions of the disk temperature of 100 ° C., the load of 200 N, the amplitude of 1.5 mm, and the frequency of 50 Hz is “A”, the friction coefficient exceeds 0.10 and is 0.150 or less. Was evaluated as “B”, and the friction coefficient exceeding 0.150 was evaluated as “C”. The results are shown in Tables 1 and 2. If the evaluation of the friction coefficient is A, it can be said that the fuel efficiency is excellent.

(Corrosion prevention against copper)
About each lubricating oil composition of an Example , a reference example, and a comparative example, the corrosion inhibitory property with respect to copper was evaluated based on the corrosion oxidation stability test (JISK2503: 2010). However, the sample amount was 100 ml, the test temperature was 135 ° C., the test time was 168 hours, the air flow rate was 5 L / h, and the catalyst was copper, lead, and tin. The results are shown in Tables 1 and 2. It can be said that the smaller the elution amount of copper (for example, 50 mass ppm or less), the more excellent the corrosion resistance to copper.

(Corrosion prevention for lead)
About each lubricating oil composition of an Example and a reference example, the corrosion inhibitory property with respect to lead was evaluated based on the corrosion oxidation stability test (JISK2503: 2010). However, the sample amount was 100 ml, the test temperature was 135 ° C., the test time was 168 hours, the air flow rate was 5 L / h, and the catalyst was copper, lead, and tin. The results are shown in Table 3. It can be said that the smaller the elution amount of lead, the better the corrosion resistance against lead.

Claims (3)

Lubricating base oil,
Based on the total amount of the lubricating oil composition,
As component (A) , 0.03% by mass or more of an organic molybdenum friction modifier in terms of molybdenum element;
(B) at least one metal-based detergent selected from the group consisting of an alkali metal phenate and an alkaline earth metal phenate in an amount of 0.05 % by mass to 0.1% by mass in terms of a metal element;
As components other than B) component contains at least one metal-based detergents selected from the group consisting of alkali metal salicylates and alkaline earth metal salicylate,
The total content of alkali metal and alkaline earth metal element in the lubricating oil composition is 1500 mass ppm or more and 2600 mass ppm or less based on the total amount of the lubricating oil composition.
Lubricating oil composition for internal combustion engines.   The lubricating oil composition for an internal combustion engine according to claim 1, wherein the base number of the metallic detergent is 200 mgKOH / g or more.   The lubricating oil composition for an internal combustion engine according to claim 1 or 2, which is used as a diesel engine oil.