JP2018184518A - Lubricating oil composition for internal-combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lubricating oil composition for an internal-combustion engine for improving fuel-efficiency while keeping HTHSV150 and KV100 defined by SAE-J300 above the lower limit value.SOLUTION: A lubricant oil composition of the present invention comprises a GTL, gas to liquid, base oil synthesized by Fischer-Tropsch process and 0.1 to 20 mass% viscosity index improver; and at least has 50°C HTHS viscosity/150°C HTHS viscosity of 6.50 or less and 50°C kinetic viscosity/150°C HTHS viscosity of 8.00 or less.SELECTED DRAWING: None

Description

  The present invention relates to a lubricating oil composition for an internal combustion engine (hereinafter sometimes referred to as an engine) that is excellent in fuel efficiency in a practical temperature range.

  The tightening of regulations for environmental conservation is currently being carried out on a global scale. With regard to automobiles in particular, fuel economy regulations and exhaust gas regulations are becoming increasingly strict, but this is based on environmental problems such as global warming, concerns over oil resource depletion, and resource protection measures. In particular, in response to demands for reducing fuel consumption of automobiles, various components of the automobile have been improved, such as reducing the weight of automobiles, improving engines that improve energy efficiency, and improving transmission efficiency of driving force.

  In order to contribute to fuel saving with engine oil, it is necessary to reduce friction loss in the engine. This friction loss is mainly due to viscous resistance under fluid lubrication conditions depending on the lubricating oil used and friction between metals at the sliding part under mixed lubrication or boundary lubrication conditions. In order to obtain this, the viscosity of the lubricating oil must be lowered than before and the viscosity resistance must be lowered. In order to lower the viscosity of the lubricating oil, it is effective to use a lower viscosity base oil and a viscosity index improver such as a comb polymer to suppress changes in viscosity due to temperature differences (for example, Patent Document 1). Patent Document 2).

Special table 2015-520285 gazette Japanese Patent No. 5502730

  Here, in particular, as a representative example of fuel saving measures for passenger cars in recent years, there is an idling stop function that works when a passenger car stops due to a signal or the like, and the engine frequently stops in traveling in an urban area. For this reason, in short-distance driving such as shopping, the temperature of the lubricating oil for the internal combustion engine does not rise sufficiently and the driving ends. Similarly, in PHV (Plug-in-Hybrid Vehicle), etc., the engine does not get warm enough for short-distance commuting or shopping due to on-off of the engine rotation as required. It is easy to get up.

  On the other hand, lowering the viscosity of engine oil is known to increase the risk of wear due to oil film rupture at high temperatures and the risk of increased friction between metals. To prevent this, the viscosity standard of SAE J300 The lower limit values of the shear viscosity at 150 ° C. (hereinafter referred to as HTHSV150) and the kinematic viscosity at 100 ° C. (hereinafter referred to as KV100) are defined. Therefore, when trying to lower the viscosity of engine oil, the lower limit of HTHSV150 and KV100 becomes a barrier, and even when used for PHV and idling stop vehicles, to achieve further fuel saving with the same viscosity grade No specific method has been proposed.

  Therefore, the present invention further improves fuel economy under comprehensive driving conditions including the situation where the engine itself is not operating, while maintaining HTHSV150 and KV100 defined in SAE J300 at or above the lower limit values. It is an object of the present invention to obtain a lubricating oil composition for an internal combustion engine capable of

  As a new approach based on the above problems, the present inventors have repeatedly studied characteristics of various temperature ranges that are not normally focused on. In particular, in an idling stop vehicle and a PHV in which engine stop and start are repeated. It has been found that fuel economy can be remarkably improved only when both the shear viscosity and the kinematic viscosity at 50 ° C. are in a specific range (a specific range in correlation with temperature characteristics in a higher temperature range). As a result, the fuel efficiency of the lubricating oil composition for an internal combustion engine can be improved while maintaining HTHSV 150 ° C. and KV 100 ° C. at or above the lower limit specified in SAE J300, and the present invention has been completed. Specifically, the present invention is as follows.

The present invention (1)
A lubricating oil composition for an internal combustion engine containing a GTL (Gas Liquid) base oil synthesized by a Fischer-Tropsch process, wherein the content of the viscosity index improver relative to the entire lubricating oil composition is 0.1 The lubricating oil composition for an internal combustion engine, which is ˜20% by mass and satisfies the following (A) to (E).
(A) High-temperature high shear viscosity (HTHSV (ASTM D4683 or ASTM D5481)) at 150 ° C. and 10 ⁶ s ⁻¹ is 1.0 mPa · s or more (B) Kinematic viscosity (KV (JIS K2283)) at 100 ° C. is 3 .0mm ² / s or more (C) HTHSV50 ℃ / HTHSV150 ℃ is 6.50 or less (D) KV50 ℃ / HTHSV150 ℃ is 8.00 or less (E) NOACK evaporation amount (JPI-5S-41) is more than 15 wt% The present invention (2)
KV100 ° C. is 1 to 8 mm ² / s, a viscosity index of 110 or more,% by ASTM D3238 _{C A} of 5 or less,% _{C P} is singly or more containing 60 or more base oil, the composition is the content of base oil The lubricating oil for internal combustion engines according to the invention (1), wherein the fraction of 380 ° C. or less in the gas chromatographic distillation according to ASTM D2887 of the whole base oil is 10% by mass or less based on the whole product It is a composition.
The present invention (3)
The lubricating oil composition for internal combustion engines according to the invention (1) or (2), which satisfies at least one of the following (F) to (I).
(F) It contains a metal-containing detergent having at least one selected from Ca and Mg, and satisfies [Ca] + [Mg] = 0.10 to 0.25. [Ca] and [Mg] are the concentrations (mass%) of calcium and magnesium in the lubricating oil composition, respectively.
(G) A succinimide-based ashless dispersant and / or a boron-modified succinimide-based ashless dispersant, and 0.01 to 0.20% by mass in terms of nitrogen concentration (based on the total amount of the lubricating oil composition) is there.
(H) 0.03 to 0.09 mass% (based on the total amount of the lubricating oil composition) of ZnDTP in terms of phosphorus concentration.
(I) An organic molybdenum compound is contained in an amount of 0.01 to 0.12% by mass (based on the total amount of the lubricating oil composition) in terms of Mo concentration.
The present invention (4)
The lubricating oil composition for internal combustion engines according to the invention (1) or (2), comprising at least one selected from a corrosion inhibitor, a phenolic antioxidant, an amine antioxidant, and a sulfur-containing additive It is a thing.
The present inventions (1) to (4) are particularly suitable for PHV and / or for idling stop vehicles.

  According to the present invention, a lubricating oil composition for an internal combustion engine that can further improve fuel economy in PHV and idling stop vehicles while maintaining HTHSV150 and KV100 at or above the lower limit values defined in SAE J300. Things are provided.

The lubricating oil composition for an internal combustion engine according to the present embodiment has a high-temperature high-shear viscosity at 150 ° C. and 10 ⁶ s ⁻¹ ((ASTM D4683 or ASTM D5481), hereinafter referred to as HTHSV) is 1.0 mPa · s or more, 100 Kinematic viscosity {(JIS K2283), hereinafter referred to as KV} is 3.0 mm ² / s or more, NOACK evaporation (JPI-5S-41) is 15% by mass or less, and HTHSV 50 ° C./HTHSV 150 ° C. ≦ It satisfies 6.50 and KV50 ° C./HTHSV 150 ° C. ≦ 8.00.

  Hereinafter, the composition, production method, properties and application of the lubricating oil composition for internal combustion engines according to the present embodiment will be described in detail, but the present invention is not limited to these.

<<< Composition >>>
The lubricating oil composition for an internal combustion engine according to this embodiment includes a base oil and a viscosity index improver, and further includes other additives as necessary. Hereinafter, the composition (blending component) of the present invention will be described.

<< Base oil >>
The base oil in the lubricating oil composition according to this embodiment contains, as an essential component, a GTL (Gas Liquid) base oil synthesized by the Fischer-Tropsch method. GTL (Gas Liquid Liquid) base oil synthesized by the Fischer-Tropsch method, which is a natural gas liquid fuel technology, has extremely low sulfur content and aromatic content compared to mineral oil base oil refined from crude oil. Since the ratio is extremely high, the evaporation loss is very small and the oxidation stability is excellent, so that it is suitable as the base oil of the present invention. The viscosity properties of the GTL base oil is not particularly limited, the kinematic viscosity at usual 100 ℃ 1.0~50.0mm ² / s, more preferably 1.0~12.0mm ² / s, more preferably 3.0 -0.0mm < ² > / s may be sufficient. Also, typically the viscosity index may be 100 to 180, preferably 105 to 160, more preferably 110 to 150.
In general, the total sulfur content may be less than 10 ppm and the total nitrogen content may be less than 1 ppm. An example of such a GTL base oil product is SHELL XHVI (registered trademark).

The lubricating oil composition according to this embodiment may contain other base oils as necessary. As other base oils, mineral oils and hydrocarbon-based synthetic oils called highly refined base oils can be used, and in particular, API (American Petroleum Institute, American Petroleum Institute) base oil category, Group 2, Group 3 and Group A base oil selected from the group consisting of base oils classified into 4 can be used. The base oil used here has a kinematic viscosity at 100 ° C. of 3.0 to 12.0 mm ² / s, preferably 3.0 to 10.0 mm ² / s, more preferably 3.0 to It may be 8.0 mm ² / s. The viscosity index of the base oil may be 100 to 180, preferably 100 to 160, more preferably 100 to 150. The sulfur element content of the base oil may be 300 ppm or less, preferably 200 ppm or less, more preferably 100 ppm or less, and even more preferably 50 ppm or less. The density of the base oil at 15 ° C. is 0.80 to 0.95 g / cm ³ , preferably 0.80 to 0.90 g / cm ³ , more preferably 0.80 to 0.85 g / cm ^3. Also good.

Group 2 base oils are, for example, paraffinic mineral oils obtained by applying a suitable combination of hydrocracking, dewaxing and other refining means to a lubricating oil fraction obtained by distillation of crude oil under reduced pressure. Can be mentioned. Also, the base oil of the Gulf Company Law Group 2, which is refined by hydrorefining methods such as, together with the total sulfur content is less than 10 ppm, aromatic content% C _A is 5 or less, the lubricating oil composition of the present embodiment It can be suitably used as a base oil blended into a product. Group 2 base oils preferably have a viscosity index (the viscosity index in the present invention is measured by ASTM D2270 and JIS K2283) of 100 or more and less than 120, and more preferably 105 or more and less than 120. The kinematic viscosity at 100 ° C. of the base oil of group 2 (the kinematic viscosity in the present invention is measured by ASTM D445 and JIS K2283) is preferably 3.0 to 12.0 mm ² / s, and preferably 3.0 to 9 More preferably, it is 0.0 mm ² / s. The group 2 base oils preferably have a total sulfur content of less than 300 ppm, more preferably less than 200 ppm, even more preferably less than 100 ppm, and particularly preferably less than 10 ppm. The total sulfur content is a value measured using a radiation excitation method (according to ASTM D4294, JIS K2541-4). The total nitrogen content of the Group 2 base oil may be less than 10 ppm, preferably less than 1 ppm. Further, the aniline point of the group 2 base oil (aniline point in the present invention is measured by ASTM D611, JIS K2256) is preferably 80 to 150 ° C, and more preferably 100 to 135 ° C.

Group 3 base oils include, for example, “paraffinic mineral oil obtained by applying advanced hydrorefining means to a lubricating oil fraction obtained by distillation of crude oil under reduced pressure”, “mobile wax (WAX) )) Base oil refined by isomerization process. The viscosity index of Group 3 base oils is preferably 120 to 150, more preferably 120 to 140. Kinematic viscosity at 100 ° C. of the base oil group 3 is preferably 3.0~12.0mm ² / s, more preferably 3.0~9.0mm ² / s. Further, the total sulfur content of the Group 3 base oils is preferably less than 100 ppm, and more preferably less than 10 ppm. The total nitrogen content of Group 3 base oils is preferably less than 10 ppm, more preferably less than 1 ppm. Furthermore, the aniline point of the group 3 base oil is preferably 80 to 150 ° C, more preferably 110 to 140 ° C.

  Group 4 base oils include polyalphaolefins (poly-α-olefins), alpha olefin oligomers (α-olefin oligomers), or mixtures thereof (polyalphaolefins and alpha olefin oligomers). Polyalphaolefin (PAO) is a polymer of various alphaolefins (monomers). The polyalphaolefin may be a mixture of not only one “alpha olefin (monomer) polymer” but also a plurality of “alpha olefin (monomer) polymer”. The alpha olefin oligomers are oligomers of various alpha olefins (monomers), and also include hydrogenated alpha olefin (monomer) oligomers. Although it does not specifically limit as an alpha olefin (monomer), For example, ethylene, propylene, butene, an alpha olefin of 5 or more carbon atoms, etc. are mentioned.

  Examples of the hydrocarbon-based synthetic oil include polyolefins including PAO described above, alkylbenzene, alkylnaphthalene, and the like, or a mixture thereof.

The viscosity of these synthetic oils is not particularly limited, the kinematic viscosity at 100 ° C., is preferably 3.0~12.0mm ² / s, more to be 3.0~10.0mm ² / s Preferably, it is 3.0-8.0 mm < ² > / s. The viscosity index of the synthetic base oil is preferably 10 to 120 in the case of alkylbenzene or alkylnaphthalene, more preferably 20 to 120, still more preferably 20 to 110, and polyalphaolefin. Is preferably 100 to 170, more preferably 110 to 170, and still more preferably 110 to 155. Density at 15 ℃ of the synthetic base oil is preferably 0.8000~0.9500g / cm ^3, more preferably 0.8100~0.9500g / cm ^3, 0.8100~0. More preferably, it is 9200 g / cm ³ .

Furthermore, as the base oil of the lubricating oil composition, a base oil belonging to Group 1 in the API (American Petroleum Institute, American Petroleum Institute) base oil category may be blended with the base oil. Group 1 base oils can be obtained, for example, by applying a suitable combination of solvent refining, hydrorefining, dewaxing and other refining means to a lubricating oil fraction obtained by atmospheric distillation of crude oil. Mention may be made of paraffinic mineral oil. The group 1 base oil used here has a kinematic viscosity at 100 ° C. of 3.0 to 35.0 mm ² / s, preferably 3.0 to 10.0 mm ² / s, more preferably 3.0 to 8. It may be 0 mm ² / s. Further, the viscosity index may be 90 to 120, preferably 95 to 115, more preferably 95 to 110. Further, the sulfur content may be 0.03 to 0.7% by mass, preferably 0.1 to 0.7% by mass, more preferably 0.4 to 0.7% by mass. The% by ASTM D3238 _{C A} of 5 or less, preferably 4 or less, and more preferably may be 3.4 or less. Moreover,% _{C P} by ASTM D3238 is 60 or more, preferably 63 or more, more preferably may be 66 or more.

The lubricating oil composition according to the present embodiment, KV100 ° C. is 1 to 8 mm ² / s, a viscosity index of 110 or more,% by ASTM D3238 _{C A} of 5 or less,% _{C P} is the base oil is 60 or higher, One or a plurality of base oils are contained so that a fraction of 380 ° C. or less in gas chromatographic distillation according to ASTM D2887 is 10% by mass or less and 50% by mass or less of the whole lubricating oil composition. Is preferred. By using such a base oil, it is possible to provide a lubricating oil composition in which part of the GTL oil is replaced with another base oil without significantly impairing the low evaporation loss characteristic of the GTL oil. It becomes possible.

<< Viscosity index improver >>
The viscosity index improver is a polymer substrate generally having a viscosity index improving effect. In this embodiment, various viscosity index improvers can be used. Examples of viscosity index improvers include non-dispersed viscosity index improvers, poly (meth) acrylates and olefin copolymers such as ethylene / propylene copolymers and styrene / diene copolymers, and copolymerization of these with nitrogen-containing monomers. Dispersion-type viscosity index improvers such as those obtained by As the viscosity index improver, a comb polymer that has a high effect of improving the viscosity index and is advantageous in reducing (designing) low temperature viscosity is desirable. The comb polymer is a known polymer and is a polymer in which a relatively long side chain is combined with a polymer main chain to form a comb shape. As such a comb polymer, known ones can be used. More specifically, for example, in the main chain, (1) a repeating unit derived from a polyolefin-based macromonomer, and (2) a styrene monomer having 8 to 17 carbon atoms, 1 to 10 in an alcohol group Alkyl (meth) acrylate having 1 to 10 carbon atoms, vinyl ester having 1 to 11 carbon atoms in acyl group, vinyl ether having 1 to 10 carbon atoms in alcohol group, 1 to 10 in alcohol group A low molecular weight monomer selected from the group consisting of (di) alkyl fumarate having 5 carbon atoms, (di) alkyl maleate having 1 to 10 carbon atoms in an alcohol group, and a mixture of these monomers A comb polymer containing the derived repeating unit can be suitably used. In particular, the degree of molar branching is 0.3 to 1.1 mol%, and (1) a repeating unit derived from a polyolefin-based macromonomer with respect to the mass of the repeating unit, and (2) 8 to 17 Styrene monomer having carbon atom, alkyl (meth) acrylate having 1 to 10 carbon atoms in alcohol group, vinyl ester having 1 to 11 carbon atoms in acyl group, 1 to 10 in alcohol group Vinyl ether having 1 to 10 carbon atoms, (di) alkyl fumarate having 1 to 10 carbon atoms in the alcohol group, (di) alkyl maleate having 1 to 10 carbon atoms in the alcohol group, and these And a repeating unit derived from a low molecular weight monomer selected from the group consisting of a monomer mixture of It comprises 8 to 30 wt% repeating units derived from the fin-based macromonomers and, it is preferable that the iodine value is less than 0.2g per comb polymer 1g.

  Here, content of a viscosity index improver is 0.1-15 mass% as a resin amount with respect to the whole lubricating oil composition, More preferably, it is 0.1-10 mass% as a resin amount.

<< Other additives >>
The lubricating oil composition according to the present embodiment is a Ca / Mg-based detergent (a metal-containing detergent having at least one selected from Ca and Mg) as an additive (other additives) other than the viscosity index improver, It is preferable to contain a succinimide-based / boron-modified succinimide-based ashless dispersant, ZnDTP, and / or a friction modifier (preferably an organic molybdenum compound). In addition, as other additives, corrosion inhibitors, phenolic antioxidants, amine-based antioxidants, and / or sulfur-containing additives can also be suitably applied. Hereinafter, such other additives will be described.

<Ca / Mg detergent>
The lubricating oil composition according to the present embodiment includes a Ca-based detergent (a detergent containing at least Ca) and / or an Mg-based detergent (a detergent containing at least Mg). ] + [Mg] = 0.10 to 0.25 {Note that [Ca] and [Mg] are the concentrations (mass%) of calcium and magnesium in the lubricating oil composition, respectively. } Is preferable. When [Ca] + [Mg] = 0.10 to 0.25, [Mg] = 0 (that is, Mg is not blended) or [Mg]> 0 (that is, Ca-based detergent) Any or all of the above may be replaced with a Mg-based detergent. When [Ca] + [Mg] is 0.25 or less, it is advantageous for improving the torque improvement rate, and when it is 0.10 or more, the cleanliness is more excellent.

  As a Ca / Mg type | system | group detergent, the well-known metal containing detergent containing calcium and / or magnesium as an alkaline-earth metal is mentioned. Such metal-containing detergents preferably contain phenate, salicylate, carboxylate or sulfonate as a main component.

<Succinimide-based / boron-modified succinimide-based ashless dispersant>
The lubricating oil composition according to this embodiment includes a succinimide-based ashless dispersant and / or a boron-modified succinimide-based ashless dispersant, and the content thereof is 0.01 to 0.20% by mass in terms of nitrogen concentration. It is preferable to satisfy (based on the total amount of the lubricating oil composition). In addition, when it is 0.20 mass% or less in terms of nitrogen concentration, it is advantageous in wear resistance.

  As the bis-type succinimide-based ashless dispersant not containing boron, known ones can be used, and examples thereof include bis-type succinimides in which succinic anhydride is added to both ends of the polyamine during imidization. As the boron-modified succinimide-based ashless dispersant, known ones can be used, and monotype succinimide and / or polyamine having both ends of polyamine added to one end of polyamine during imidization. Examples thereof include succinimide obtained by boron-modifying bis-type succinimide to which an acid is added.

<ZnDTP>
The lubricating oil composition according to this embodiment preferably contains ZnDTP and satisfies 0.03 to 0.09 mass% (based on the total amount of the lubricating oil composition) as the phosphorus content with respect to the content thereof. . In addition, ZnDTP has a function as an antiwear agent, and when the phosphorus content is 0.03% by mass or more, the wear resistance is more excellent. Moreover, when it is 0.09 mass% or less as phosphorus content, it is hard to inhibit the effect of a friction modifier.

ZnDTP is an abbreviation for Zinc Dialkyldithiophosphate (zinc dialkyldithiophosphate) and is represented by the following structural formula (1). In the formula, R represents a mutually independent hydrocarbon group. A primary or secondary C3-C20 alkyl group is preferred. More preferably, it is a primary or secondary C3-C10 alkyl group.

<Friction modifier>
In the lubricating oil composition according to the present embodiment, any compound usually used as a friction modifier for lubricating oil can be used, and examples thereof include organic molybdenum compounds and ashless friction modifiers. The organomolybdenum compound and the ashless friction modifier can be used alone or in combination.

  Known organic molybdenum compounds can be used, such as molybdenum dithiocarbamate (sometimes simply referred to as MoDTC or the like), trinuclear molybdenum compounds described in WO-98 / 26030, molybdenum sulfide, molybdenum dithiophosphorus. Acid salts, molybdenum-amine complexes, molybdenum-succinimide complexes, molybdenum salts of organic acids, molybdenum salts of alcohols, and the like. Moreover, as content, it is suitable to satisfy | fill 0.01-0.12 mass% (total quantity reference | standard of a lubricating oil composition) in conversion of Mo density | concentration by arbitrary combinations of these organic molybdenum compounds. In addition, when it is 0.12 mass% or less in terms of Mo concentration, the storage stability is more excellent.

  As the ashless friction modifier, known ones can be used. For example, an alkyl group or alkenyl group having 3 to 30 carbon atoms, particularly a linear alkyl group or linear alkenyl group having 3 to 30 carbon atoms in the molecule. Examples include ashless friction modifiers such as amine compounds, fatty acid esters, fatty acid amides, fatty acids, aliphatic alcohols, and aliphatic ethers that have at least one. Some or all of these alkyl groups or alkenyl groups may be substituted with alkoxy groups, or carbon atoms of the alkyl groups or alkenyl groups may be substituted with heteroatoms. In addition, although it does not specifically limit as content of an ashless friction modifier, For example, it is suitable to satisfy | fill 0.01-1.0 mass% (total quantity basis of a lubricating oil composition). In addition, when it is 1.0 mass% or less, storage stability and seal compatibility are more excellent.

  In the present invention, molybdenum dithiocarbamate is most preferable from the viewpoint that friction can be reduced most.

<Corrosion inhibitor>
The lubricating oil composition according to this embodiment preferably contains a corrosion inhibitor.

  As the corrosion inhibitor, known ones can be used, and examples thereof include benzotriazole, tolyltriazole, thiadiazole, and imidazole compounds.

  In addition, although it does not specifically limit as content of a corrosion inhibitor, For example, what is necessary is just to be 0.01-0.1 mass% (total quantity basis of a lubricating oil composition).

<Phenolic antioxidant and / or amine antioxidant>
The lubricating oil composition according to this embodiment preferably contains a phenolic antioxidant and / or an amine antioxidant as an ashless antioxidant.

  Known phenolic antioxidants can be used, for example, 4,4'-methylenebis (2,6-di-tert-butylphenol), 4,4'-bis (2,6-di-). tert-butylphenol) and the like. As the amine-based antioxidant, known ones can be used, and examples thereof include aromatic amine compounds such as alkyldiphenylamine, alkylnaphthylamine, phenyl-α-naphthylamine, and alkylphenyl-α-naphthylamine.

  Although it does not specifically limit as content of an amine antioxidant, For example, what is necessary is just to set it as 0.1-2.0 mass% (total quantity of lubricating oil composition). Moreover, it is not specifically limited as content of a phenolic antioxidant, For example, what is necessary is just to be 0.1-2.0 mass% etc. with respect to the whole lubricating oil composition.

<Sulfur-containing additive>
The lubricating oil composition according to this embodiment preferably contains a sulfur-containing additive. In addition, the sulfur containing additive shown here shows the sulfur compound except ZnDTP and MoDTC mentioned above, and it is preferably selected as a component further added after adding MoDTC.

  As such sulfur-containing additives, known ones can be used, and examples thereof include sulfurized fats and oils, sulfur-crosslinked metal phenates, dihydrocarbyl polysulfides, and dithiocarbamates other than MoDTC.

  In addition, although it does not specifically limit as content of a sulfur containing additive, For example, what is necessary is just to be 0.1 mass%-2.0 mass% etc. with respect to the whole lubricating oil composition.

<Other ingredients>
Furthermore, in the lubricating oil composition according to the present embodiment, additives other than the above, such as antioxidants, ashless dispersants, metal detergents, friction modifiers, rust inhibitors, antifoaming agents, etc., as necessary. Can be included. Further, an additive package in which a part or all of the additive to be blended is packaged can be used (or used together).

  The content of such other components is not particularly limited. For example, as an additive other than the base oil considering the diluent oil contained in each additive including a viscosity index improver, a lubricating oil composition What is necessary is just to set it as 10 mass%-30 mass% etc. with respect to the whole thing.

<<< Manufacturing method >>>
The manufacturing method of the lubricating oil composition according to the present embodiment is not particularly limited, and for example, the lubricating oil composition can be manufactured by adding and mixing the above-described components in an arbitrary procedure.

<<< Properties >>>
The lubricating oil composition according to this embodiment has all the following properties (A) to (E).
(A) High-temperature high shear viscosity (HTHSV (ASTM D4683 or ASTM D5481)) at 150 ° C. and 10 ⁶ s ⁻¹ is 1.0 mPa · s or more (B) Kinematic viscosity (KV (JIS K2283)) at 100 ° C. is 3 .0mm ² / s or more (C) HTHSV50 ℃ / HTHSV150 ℃ is 6.50 or less (D) KV50 ℃ / HTHSV150 ℃ is 8.00 or less (E) NOACK evaporation amount (JPI-5S-41) is more than 15 wt%

The lubricating oil composition according to the present embodiment has (A) 150 ° C., 10 ⁶ s ⁻¹ by setting HTHSV 50 ° C./HTHSV 150 ° C. to 6.50 or less and KV50 ° C./HTHSV 150 ° C. to 8.00 or less. Even when the high-temperature high-shear viscosity (HTHSV (ASTM D4683 or ASTM D5481)) is 1.0 mPa · s or more and the kinematic viscosity (KV) at 100 ° C. is 3.0 mm ² / s or more, 15 It becomes possible to satisfy NOACK evaporation of less than mass% (JPI-5S-41) and improve fuel efficiency.

  In order to achieve the above (C) and (D), it is effective to lower the solubility in the base oil than the existing viscosity index improver and increase the temperature at which the polymer is completely dissolved. . For example, when the viscosity index improver is PMA, the viscosity can be adjusted by increasing the chain length of R (long chain alkyl chain) of the —COOR group, which is a component of PMA, and increasing the polarity of PMA.

<<< Use >>>
Although the lubricating oil composition according to the present embodiment can be used as a lubricating oil composition for a normal internal combustion engine, the lubricating oil for a PHV internal combustion engine and / or an internal combustion engine for an idling stop vehicle Particularly suitable as a composition.

<< Raw material >>
The following raw materials were blended so as to have the blending amounts (mass%) shown in Table 1, and lubricating oil compositions according to Examples 1 and 2 and Comparative Examples 1 to 5 were obtained. In this example, those having a HTHSV at 150 ° C. of 2.5 or more in the composition were classified as equivalent to 0W-20, and those having less than 0W-16 were classified as equivalent to 0W-16.

<Base oil>
SHELL XHVI (registered trademark) 4 (GTL base oil)
SHELL XHVI (registered trademark) 3 (GTL base oil)
<DI package>
The main ingredients of the package used are shown below.
・ Package A
Highly refined mineral oil, succinimide-based ashless dispersant, calcium-based metal detergent, ZnDTP, amine-based antioxidant mixture / Package B
Highly refined mineral oil, succinimide-based ashless dispersant, calcium-based metal detergent, magnesium-based metal detergent, ZnDTP, amine-based antioxidant mixture / package C
Highly refined mineral oil, succinimide ashless dispersant, magnesium metal detergent, calcium metal detergent, ZnDTP, amine friction modifier, amine antioxidant, phenol antioxidant mixture <viscosity index improvement Agent>
・ Viscosity index improver E Non-comb PMA
・ Viscosity index improver F OCP
・ Viscosity index improvers D, G, H Comb PMA
Here, the viscosity index improvers D, G, and H are comb-shaped PMAs produced under different conditions, and have different polarities with different repeat numbers and chain lengths of long alkyl chains.
<Friction modifier>
・ Sakurarube 525 (MoDTC (Molybdenum Dithiocarbamate), manufactured by ADEKA Corporation)
<Antifoaming agent>
-DCF 3% mass solution in which 3% by mass of polymethylsiloxane (silicone oil) with a weight average molecular weight of about 30,000 is dissolved in JIS No. 1 kerosene

  Here, in Table 2, the concentrations of B, Ca, Mg, Mo, P, Zn, N, and S in the lubricating oil compositions according to Comparative Examples 1 to 5 and Examples 1 to 4 (mass%, lubricating oil composition) Is based on the total amount). The measurement method conforms to JPI-5S-38 for B, Ca, Mg, Mo, P, and Zn, JIS K2609 for N, and JIS K2541-4 (radiation excitation method) for S.

<< Evaluation >>
Next, regarding each lubricating oil composition, high temperature high shear viscosity (50 ° C., 150 ° C.) based on ASTM D5481, kinematic viscosity (40 ° C., 50 ° C., 100 ° C.) based on JIS K 2283, The NOACK evaporation amount was measured based on 5S-41, and fuel economy was further evaluated. The evaluation results are shown in Table 3. The evaluation method of fuel efficiency is as follows.

The engine was driven by an electric motor, and the force required (friction torque) was measured with a torque meter. As the engine, an in-line 4-cylinder 2.0 L direct injection engine was used, and the test oil temperature was 50 ° C. and the rotation speed was 2000 rpm (the lubricating oil composition of Comparative Example 1 was used as the reference oil).
Note that the test oil temperature was set to 50 ° C. assuming a running state in which the engine oil temperature is unlikely to rise, such as the start of running in a general passenger car and idling stop vehicles and PHV.

  From Table 3, comparison between equivalent viscosity grades, ie, comparison of Comparative Example 1, Example 1 and Example 3 as equivalent to 0W-20, and Comparative Example 2, Comparative Example 3 as implementation of 0W-16 By comparing Example 2 and Example 4, fuel efficiency can be improved by setting HTHSV50 ° C / HTHSV150 ° C to 6.50 or less and KV50 ° C / HTHSV150 ° C to 8.00 or less. It is understood.

Claims (4)

A lubricating oil composition for an internal combustion engine containing a GTL (Gas Liquid) base oil synthesized by a Fischer-Tropsch process, wherein the content of the viscosity index improver relative to the entire lubricating oil composition is 0.1 A lubricating oil composition for an internal combustion engine, which is ˜20 mass% and satisfies the following (A) to (E).
(A) High-temperature high shear viscosity (HTHSV (ASTM D4683 or ASTM D5481)) at 150 ° C. and 10 ⁶ s ⁻¹ is 1.0 mPa · s or more (B) Kinematic viscosity (KV (JIS K2283)) at 100 ° C. is 3 .0mm ² / s or more (C) HTHSV50 ℃ / HTHSV150 ℃ is 6.50 or less (D) KV50 ℃ / HTHSV150 ℃ is 8.00 or less (E) NOACK evaporation amount (JPI-5S-41) is more than 15 wt% KV100 ° C. is 1 to 8 mm ² / s, a viscosity index of 110 or more,% by ASTM D3238 _{C A} of 5 or less,% _{C P} is singly or more containing 60 or more base oil, lubricating the content of base oil It is 50 mass% or less with respect to the whole oil composition, and the fraction for 380 degrees C or less in the gas chromatographic distillation by ASTM D2887 of the whole base oil is 10 mass% or less for internal combustion engines of Claim 1 Lubricating oil composition. The lubricating oil composition for an internal combustion engine according to claim 1 or 2, which satisfies at least one of the following (F) to (I).
(F) It contains a metal-containing detergent having at least one selected from Ca and Mg, and satisfies [Ca] + [Mg] = 0.10 to 0.25. [Ca] and [Mg] are the concentrations (mass%) of calcium and magnesium in the lubricating oil composition, respectively.
(G) A succinimide-based ashless dispersant and / or a boron-modified succinimide-based ashless dispersant, and 0.01 to 0.20% by mass in terms of nitrogen concentration (based on the total amount of the lubricating oil composition) is there.
(H) 0.03 to 0.09 mass% (based on the total amount of the lubricating oil composition) of ZnDTP in terms of phosphorus concentration.
(I) An organic molybdenum compound is contained in an amount of 0.01 to 0.12% by mass (based on the total amount of the lubricating oil composition) in terms of Mo concentration. The lubricating oil composition for an internal combustion engine according to any one of claims 1 to 3, comprising at least one selected from a corrosion inhibitor, a phenol-based antioxidant, an amine-based antioxidant, and a sulfur-containing additive.