JP6936041B2 - Lubricating oil composition for internal combustion engine - Google Patents

Description

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

Tightening of regulations on environmental protection is currently taking place on a global scale. Especially for automobiles, fuel consumption regulations and emission regulations are becoming more and more strict, but this is based on environmental problems such as global warming, concerns about depletion of petroleum resources, and resource protection measures. In particular, in response to the demand for fuel efficiency of automobiles, various components of automobiles have been improved, such as weight reduction of automobiles, improvement of engines for improving energy efficiency, and improvement of transmission efficiency of driving force.

In order to contribute to fuel efficiency with engine oil, it is necessary to reduce friction loss in the engine. This friction loss is mainly due to the viscous resistance of the lubricating oil used under fluid lubrication conditions and the friction between metals in the sliding parts under mixed lubrication or boundary lubrication conditions, resulting in a better fuel saving effect. In order to obtain the lubricating oil, the viscosity of the lubricating oil must be made lower than before, and the viscous resistance must be lowered. In order to reduce the viscosity of the lubricating oil, it is effective to suppress the change in viscosity due to the difference in temperature by using a base oil having a lower viscosity and a viscosity index improver such as a comb-shaped polymer (for example, Patent Document 1). , Patent Document 2).

Special Table 2015-520285 Patent No. 5502730

Here, as a typical example of fuel-saving measures for passenger cars in recent years, there is an idling stop function that works when the passenger car stops at a traffic light or the like, and the engine frequently stops when traveling in an urban area. Therefore, in short-distance operation such as shopping, the oil temperature of the lubricating oil for the internal combustion engine does not rise sufficiently and the operation ends. Similarly, in PHVs (Plug-in-Hybrid Vehicles) and the like, the engine may not be sufficiently warmed up for short-distance commuting or shopping due to the on-off of engine rotation as needed. The situation is easy to get up.

On the other hand, it is known that lowering the viscosity of engine oil increases the risk of wear due to breakage of the oil film at high temperature and increase in friction between metals. The lower limit values of the shear viscosity at 150 ° C. (hereinafter, HTHSV150) and the kinematic viscosity at 100 ° C. (hereinafter, KV100) are specified. Therefore, when trying to reduce the viscosity of engine oil, the lower limit values of HTHSV150 and KV100 become a barrier, and even when it is used for PHVs and idling stop vehicles, it is possible to realize further fuel efficiency with the same viscosity grade. No specific method was proposed.

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

Based on the above problems, the present inventors have repeatedly studied the characteristics of various temperature ranges, which are not usually paid attention to, as a new approach. Especially in idling stop vehicles and PHVs in which the engine is repeatedly stopped and started. , It was found that fuel efficiency can be remarkably improved only when both the shear viscosity and the kinematic viscosity at 50 ° C. are set to a specific range (a specific range in the correlation with the temperature characteristics in a higher temperature range). As a result, the present invention has been completed by making it possible to improve the fuel efficiency of the lubricating oil composition for an internal combustion engine while maintaining HTHSV 150 ° C. and KV 100 ° C. above the lower limit values specified in SAE J300. Specifically, the present invention is as follows.

The present invention (1)
A lubricating oil composition for an internal combustion engine containing a GTL (gast liquid) base oil synthesized by the Fisher Tropsch method, and the content of the viscosity index improver in the entire lubricating oil composition is 0.1 as the amount of resin. It is a lubricating oil composition for an internal combustion engine, which is about 20% by mass and satisfies the following (A) to (E).
(A) High temperature and high shear viscosity (HTHSV (ASTM D4683 or ASTM D5481)) at 150 ° C., 10 ⁶ s ^-1 is 1.0 mPa · s or more (B) Dynamic viscosity at 100 ° C. (KV (JIS K2283)) is 3. .0 mm ² / s or more (C) ASTMV 50 ° C./HTHSV150 ° C. is 6.50 or less (D) KV50 ° C./HTHSV150 ° C. is 8.00 or less (E) NOACK evaporation amount (JPI-5S-41) is 15% by mass or less 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 Lubricating oil for internal combustion engine according to the above invention (1), which is 50% by mass or less based on the whole product, and the fraction of the whole base oil at 380 ° C. or lower in gas chromatodistillation by ASTM D2887 is 10% by mass or less. It is a composition.
The present invention (3)
The lubricating oil composition for an internal combustion engine according to the invention (1) or (2), which satisfies at least one of the following (F) to (I).
(F) 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) Contains an imide-based succinimide-based dispersant and / or a boron-modified imide-based succinimide-based dispersant, and in terms of nitrogen concentration, 0.01 to 0.20% by mass (based on the total amount of the lubricating oil composition). be.
(H) ZnDTP is contained in an amount of 0.03 to 0.09% by mass (based on the total amount of the lubricating oil composition) in terms of phosphorus concentration.
(I) The 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 an internal combustion engine according to the invention (1) or (2), which comprises at least one selected from a corrosion inhibitor, a phenolic antioxidant, an amine-based antioxidant, and a sulfur-containing additive. It is a thing.
The present inventions (1) to (4) are particularly suitable for PHVs and / or for idling stop vehicles.

According to the present invention, a lubricating oil composition for an internal combustion engine capable of further improving fuel efficiency even in PHVs and idling stop vehicles while maintaining HTHSV150 and KV100 above the lower limit values specified in SAE J300. Things are provided.

The lubricating oil composition for an internal combustion engine according to this embodiment has a high temperature and high shear viscosity {(ASTM D4683 or ASTM D5481), hereinafter referred to as HTHSV} at ^{150 ° C., 10 6} s ^{-1, and is 100 mPa · s or more.} The kinematic viscosity at ° C. {(JIS K2283), hereinafter referred to as KV} satisfies 3.0 mm ² / s or more, the NOACK evaporation amount (JPI-5S-41) satisfies 15% by mass or less, and HTHSV 50 ° C./HTHSV150 ° C.≤ 6.50 and KV50 ° C./HTHSV150 ° C.≤8.00 are satisfied.

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

<<< Composition >>>
The lubricating oil composition for an internal combustion engine according to the present embodiment contains a base oil and a viscosity index improver, and further contains 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 the present embodiment contains a GTL (gas to liquid) base oil synthesized by the Fischer-Tropsch method as an essential component. GTL (Gas to Liquids) base oil synthesized by the Fischer-Tropsch method, which is a technology for converting natural gas into liquid fuel, has an extremely low sulfur content and aromatic content compared to mineral oil base oil refined from crude oil, and has a paraffin composition. 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 It may be 1 to 10.0 mm ^{2 / s.} In addition, the viscosity index is usually 100 to 180, preferably 105 to 160, and more preferably 110 to 150.
In addition, the total sulfur content may be less than 10 ppm and the total nitrogen content may be less than 1 ppm. As an example of such a GTL base oil product, SHELL XHVI® can be mentioned.

The lubricating oil composition according to this embodiment may contain other base oils, if necessary. As other base oils, mineral oils called highly refined base oils and hydrocarbon-based synthetic oils can be used. In particular, in the API (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, and more preferably 3.0 to 3.0 to 1. It may be 8.0 mm ² / s. The viscosity index of the base oil may be 100 to 180, preferably 100 to 160, and 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 further 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} , and more preferably ^{0.80 to 0.85 g / cm 3.} May be good.

As the base oil of Group 2, for example, a paraffinic mineral oil obtained by appropriately combining refining means such as hydrocracking and dewaxing with a lubricating oil fraction obtained by distilling 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 to be blended in a product. The viscosity index of the base oil of Group 2 (the viscosity index in the present invention is measured by ASTM D2270 and JIS K2283) is preferably 100 or more and less than 120, and more preferably 105 or more and less than 120. The kinematic viscosity of the base oil of Group 2 at 100 ° C. (the kinematic viscosity in the present invention is measured by ASTM D445, JIS K2283) is ^{preferably 3.0 to 12.0 mm 2} / s, preferably 3.0 to 9. More preferably, it is 0.0 mm ^{2 / s.} Further, the base oil of Group 2 preferably has a total sulfur content of less than 300 ppm, more preferably less than 200 ppm, further 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 (ASTM D4294 compliant, 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 base oil of Group 2 (the aniline point in the present invention is measured by ASTM D611 and JIS K2256) is preferably 80 to 150 ° C., more preferably 100 to 135 ° C.

Examples of the base oil of Group 3 include "paraffinic mineral oil obtained by applying advanced hydrorefining means to a lubricating oil fraction obtained by distilling crude oil under reduced pressure" and "mobile wax (WAX). ) Base oil refined by an isomerization process ”and the like. The viscosity index of the base oil of Group 3 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. The total sulfur content of the base oil of Group 3 is preferably less than 100 ppm, more preferably less than 10 ppm. The total nitrogen content of the base oil of Group 3 is preferably less than 10 ppm, more preferably less than 1 ppm. Further, the aniline point of the base oil of Group 3 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), and mixtures thereof (polyalphaolefins and alphaolefin oligomers). Polyalphaolefin (PAO) is a polymer of various alphaolefins (monomers). Further, the polyalphaolefin may be a mixture of not only one kind of "polymer of alpha olefin (monomer)" but also a plurality of kinds of "polymer of alpha olefin (monomer)". The alpha olefin oligomer is an oligomer of various alpha olefins (monomers), and also includes an oligomer of hydrogenated alpha olefins (monomers). The alpha olefin (monomer) is not particularly limited, and examples thereof include ethylene, propylene, butene, and alpha olefin having 5 or more carbon atoms.

Examples of the hydrocarbon-based synthetic oil include the above-mentioned polyolefins containing PAO and the like, alkylbenzenes, alkylnaphthalene and the like, or mixtures 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 It is preferably 3.0 to 8.0 mm ² / s, more preferably 3.0 to 8.0 mm. 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, further preferably 20 to 110, and in the case of polyalphaolefin. Is preferably 100 to 170, more preferably 110 to 170, and even 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. It is more preferably 9200 g / cm ^3.

Further, as the base oil of the present lubricating oil composition, a base oil belonging to Group 1 in the API (American Petroleum Institute) base oil category may be blended with the base oil. The base oil of Group 1 can be obtained, for example, by applying a refining means such as solvent refining, hydrorefining, and dewaxing to a lubricating oil fraction obtained by atmospheric distillation of crude oil in an appropriate combination. Paraffinic mineral oil can be mentioned. 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, and 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, and 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, and 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 it 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, The total base oil should be contained alone or in combination so that the distillate of 380 ° C. or lower in gas chromatodistillation by ASTM D2887 is 10% by mass or less and 50% by mass or less of the entire lubricating oil composition. Is preferable. By using such a base oil, it is possible to provide a lubricating oil composition in which a part of the GTL oil is replaced with another base oil without significantly impairing the low evaporation loss characteristic of the GTL oil. It will be possible.

<< Viscosity index improver >>
The viscosity index improver is generally a polymer base material having a viscosity index improving effect. In this embodiment, various viscosity index improvers can be used. Examples of viscosity index improvers include poly (meth) acrylates and olefin copolymers such as ethylene / propylene copolymers and styrene / diene copolymers as non-dispersive viscosity index improvers, and copolymerization of these with nitrogen-containing monomers. Dispersed viscosity index improvers such as those obtained by As the viscosity index improver, a comb-shaped polymer having a high viscosity index improving effect and being advantageous in reducing (designing) low-temperature viscosity is desirable. The comb-shaped polymer is a known polymer, and is a polymer in which a relatively long side chain is bonded to a polymer main chain to form a comb shape. As such a comb-shaped polymer, known ones can be used. More specifically, for example, (1) a repeating unit derived from a polyolefin-based macromonomer, (2) a styrene monomer having 8 to 17 carbon atoms in the main chain, and 1 to 10 in an alcohol group. Alkyl (meth) acrylate having a carbon atom of, vinyl ester having 1 to 11 carbon atoms in an acyl group, vinyl ether having 1 to 10 carbon atoms in an alcohol group, 1 to 10 in an alcohol group. To a low molecular weight monomer selected from the group consisting of (di) alkyl fumarate having a carbon atom of, (di) alkyl maleate having 1 to 10 carbon atoms in an alcohol group, and a mixture of these monomers. A comb-shaped polymer containing a repeating unit from which it is derived can be preferably used. In particular, the degree of molar branching is 0.3 to 1.1 mol%, and with respect to the mass of the above repeating unit, (1) repeating units derived from a polyolefin-based macromonomer and (2) 8 to 17 repeating units. A styrene monomer having a carbon atom, an alkyl (meth) acrylate having 1 to 10 carbon atoms in an alcohol group, a vinyl ester having 1 to 11 carbon atoms in an acyl group, and 1 to 10 in an alcohol group. Vinyl ether having 1 to 10 carbon atoms in the alcohol group, (di) alkyl humarate having 1 to 10 carbon atoms in the alcohol group, (di) alkyl polymer having 1 to 10 carbon atoms in the alcohol group, and these. A total of at least 80% by weight of repeating units derived from low molecular weight monomers selected from the group consisting of a mixture of monomers of the above, and 8 to 30% by mass of repeating units derived from polyolefin-based macromonomers. Moreover, it is preferable that the iodine value is 0.2 g or less per 1 g of the comb-shaped polymer.

Here, the content of the viscosity index improver is 0.1 to 15% by mass as a resin amount, and more preferably 0.1 to 10% by mass as a resin amount with respect to the entire lubricating oil composition.

<< Other additives >>
The lubricating oil composition according to the present embodiment contains Ca / Mg-based cleaning agents (metal-containing cleaning agents having at least one selected from Ca and Mg) as additives (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). Further, as other additives, corrosion inhibitors, phenolic antioxidants, amine-based antioxidants, and / or sulfur-containing additives are also suitably applicable. Hereinafter, such other additives will be described.

<Ca / Mg-based cleaning agent>
The lubricating oil composition according to this embodiment contains a Ca-based cleaning agent (cleaning agent containing at least Ca) and / or an Mg-based cleaning agent (cleaning agent containing at least Mg), and the content thereof is [Ca. ] + [Mg] = 0.10 to 0.25 {Note that [Ca] and [Mg] are the concentrations (% by 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 cleaning agent). A part or all of the above may be replaced with an Mg-based cleaning agent.). When [Ca] + [Mg] is 0.25 or less, it is advantageous in improving the torque improvement rate, and when it is 0.10 or more, the cleanliness is more excellent.

Examples of the Ca / Mg-based cleaning agent include known metal-containing cleaning agents containing calcium and / or magnesium as alkaline earth metals. It is preferable that such a metal-containing cleaning agent contains phenate, salicylate, carboxylate or sulfonate as a main component.

<Imide succinimide / Boron-modified imide succinimide dispersant>
The lubricating oil composition according to this embodiment contains an imide-based succinimide-based dispersant and / or a boron-modified imide-based succinimide-based dispersant, and the content thereof is 0.01 to 0.20% by mass in terms of nitrogen concentration. It is preferable to satisfy (the total amount standard of the lubricating oil composition). When the nitrogen concentration is 0.20% by mass or less, it is advantageous in terms of wear resistance.

As the boron-free bistype succinimide-based ashless dispersant, known ones can be used, and examples thereof include bistype succinimide in which succinic anhydride is added to both ends of the polyamine at the time of imidization. As the boron-modified succinimide-based ashless dispersant, known ones can be used, and succinic anhydride is added to one end of the polyamine at the time of imidization, and succinic anhydride is added to both ends of the monotype succinimide and / or the polyamine. Examples thereof include succinimide obtained by boron-modifying the bis-type succinimide to which an acid has been added.

<ZnDTP>
It is preferable that the lubricating oil composition according to the present embodiment contains ZnDTP and satisfies the phosphorus content of 0.03 to 0.09% by mass (based on the total amount of the lubricating oil composition) with respect to the content thereof. .. ZnDTP has a function as an abrasion resistant agent, and when the phosphorus content is 0.03% by mass or more, the abrasion resistance is more excellent. Further, when the phosphorus content is 0.09% by mass or less, the effect of the friction modifier is hardly impaired.

ZnDTP is an abbreviation for Zinc Dialdythiophosphate (zinc dialkyldithiophosphate) and is represented by the following structural formula (1). In the formula, R represents a hydrocarbon group that is independent of each other. It is preferably a primary or secondary C3-C20 alkyl group. 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 an organic molybdenum compound and an ashless friction modifier. The organic molybdenum compound and the ashless friction modifier can be used alone or in combination.

Known organic molybdenum compounds can be used, for example, molybdenum dithiocarbamate (may be simply MoDTC or the like), trinuclear molybdenum compound described in WO-98 / 26030, molybdenum sulfide, molybdenum dithioline. Examples thereof include acid salts, molybdenum-amine complexes, molybdenum-succinateimide complexes, molybdenum salts of organic acids, and molybdenum salts of alcohols. Further, as the content, it is preferable to satisfy 0.01 to 0.12% by mass (based on the total amount of the lubricating oil composition) in terms of Mo concentration by any combination of these organic molybdenum compounds. When the Mo concentration is 0.12% by mass or less, the storage stability is more excellent.

Known ashless friction modifiers can be used, for example, an alkyl group or an alkenyl group having 3 to 30 carbon atoms, particularly a linear alkyl group or a linear alkenyl group having 3 to 30 carbon atoms is contained in the molecule. Examples thereof include ashless friction modifiers having at least one amine compound, fatty acid ester, fatty acid amide, fatty acid, aliphatic alcohol, aliphatic ether and the like. In addition, a part or all of these alkyl groups or alkenyl groups may be substituted with an alkoxy group, or the carbon atom of the alkyl group or the alkenyl group may be substituted with a heteroatom. The content of the ash-free friction modifier is not particularly limited, but it is preferable to satisfy, for example, 0.01 to 1.0% by mass (based on the total amount of the lubricating oil composition). When it is 1.0% by mass or less, the storage stability and the seal compatibility are more excellent.

In the present invention, molybdenum dithiocarbamate is most suitable from the viewpoint of reducing friction most.

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

Known corrosion inhibitors can be used, and examples thereof include benzotriazole-based, tolyltriazole-based, thiadiazole-based, and imidazole-based compounds.

The content of the corrosion inhibitor is not particularly limited, but may be, for example, 0.01 to 0.1% by mass (based on the total amount of the lubricating oil composition).

<Phenol-based antioxidants and / or amine-based antioxidants>
The lubricating oil composition according to this embodiment preferably contains a phenol-based antioxidant and / or an amine-based 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. Known amine-based antioxidants can be used, and examples thereof include aromatic amine compounds such as alkyldiphenylamine, alkylnaphthylamine, phenyl-α-naphthylamine, and alkylphenyl-α-naphthylamine.

The content of the amine-based antioxidant is not particularly limited, but may be, for example, 0.1 to 2.0% by mass (based on the total amount of the lubricating oil composition). Further, the content of the phenolic antioxidant is not particularly limited, and may be, for example, 0.1 to 2.0% by mass with respect to the entire lubricating oil composition.

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

As such a sulfur-containing additive, known ones can be used, and examples thereof include sulfide fats and oils, sulfur-crosslinked metal phenates, dihydrocarbyl polysulfide, and dithiocarbamates other than MoDTC.

The content of the sulfur-containing additive is not particularly limited, but may be, for example, 0.1% by mass to 2.0% by mass with respect to the entire lubricating oil composition.

<Other ingredients>
Further, in the lubricating oil composition according to the present embodiment, if necessary, additives other than the above, such as antioxidants, ashless dispersants, metal cleaners, friction modifiers, rust preventives, and defoamers, are added. Can be included. In addition, an additive package or the like in which a part or all of the additives to be blended is packaged can be used (or can be used in combination).

The content of such other components is not particularly limited, but for example, a lubricating oil composition can be used as an additive other than the base oil in consideration of the diluting oil contained in each additive such as the viscosity index improver. It may be 10% by mass to 30% by mass or the like with respect to the whole object.

<<< Manufacturing method >>>
The method for producing the lubricating oil composition according to this embodiment is not particularly limited, and for example, it can be produced by adding and mixing each of the above-mentioned components by an arbitrary procedure.

<<< Properties >>>
The lubricating oil composition according to this embodiment has all the following properties (A) to (E).
(A) High temperature and high shear viscosity (HTHSV (ASTM D4683 or ASTM D5481)) at 150 ° C., 10 ⁶ s ^-1 is 1.0 mPa · s or more (B) Dynamic viscosity at 100 ° C. (KV (JIS K2283)) is 3. .0 mm ² / s or more (C) ASTMV 50 ° C./HTHSV150 ° C. is 6.50 or less (D) KV50 ° C./HTHSV150 ° C. is 8.00 or less (E) NOACK evaporation amount (JPI-5S-41) is 15% by mass or less

The lubricating oil composition according to the present embodiment, the HTHSV50 ℃ / HTHSV150 ℃ and 6.50 or less, and, by a 8.00 or less KV50 ℃ / HTHSV150 ℃, (A ) 150 ℃, 10 6 s -1 High temperature and 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. It is possible to satisfy the NOACK evaporation amount (JPI-5S-41) of mass% or less and improve the fuel saving property.

In order to specifically achieve the above (C) and (D), it is effective to lower the solubility in the base oil as compared with the existing viscosity index improver and raise the temperature at which the polymer is completely dissolved. .. For example, when the viscosity index improver is PMA, it can be adjusted by lengthening 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.

<<< Applications >>>
The lubricating oil composition according to this embodiment can be used as a lubricating oil composition for a normal internal combustion engine, but is a lubricating oil for a PHV internal combustion engine and / or for an internal combustion engine of an idling stop vehicle. Especially suitable as a composition.

<< Raw materials >>
The following raw materials were blended so as to have the blending amount (mass%) shown in Table 1 to obtain the lubricating oil compositions according to Examples 1 and 2 and Comparative Examples 1 to 5. In this example, the composition having an HTHSV of 2.5 or more at 150 ° C. was classified as equivalent to 0W-20, and the composition having a HTHSV of less than 2.5 was 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
Mixture / Package B of highly refined mineral oil, imide succinate-based dispersant, calcium-based metal detergent, ZnDTP, and amine-based antioxidant
Mixture / Package C of highly refined mineral oil, succinate imide-based ashless dispersant, calcium-based metal cleaning agent, magnesium-based metal cleaning agent, ZnDTP, and amine-based antioxidant
Highly refined mineral oil, succinate imide-based ashless dispersant, magnesium-based metal cleaning agent, calcium-based metal cleaning agent, ZnDTP, amine-based friction modifier, amine-based antioxidant, phenol-based antioxidant mixture <viscosity index improvement Agent>
・ Viscosity index improver E Non-comb type PMA
・ Viscosity index improver FOCP
・ Viscosity index improver D, G, H comb-shaped PMA
Here, the viscosity index improvers D, G, and H are comb-shaped PMAs manufactured under different conditions, and show different polarities due to differences in the number of repetitions, the chain length of the long-chain alkyl chain, and the like.
<Friction modifier>
・ Sakuralube 525 (MoDTC (Molybdenum Dithiocarbamate), manufactured by ADEKA CORPORATION)
<Defoamer>
-DCF 3% mass solution in which 3% by mass of polymethylsiloxane (silicone oil) having a weight average molecular weight of about 30,000 is dissolved in JIS No. 1 kerosene.

Here, Table 2 shows the concentrations of B, Ca, Mg, Mo, P, Zn, N, and S (mass%, lubricating oil composition) in the lubricating oil compositions according to Comparative Examples 1 to 5 and Examples 1 to 4. (Total amount standard) is shown. The measuring method is based on JIS K2609 for B, Ca, Mg, Mo, P and Zn, JIS K2609 for N, and JIS K2541-4 (radiation excitation method) for S.

<< Evaluation >>
Next, for each lubricating oil composition, the high temperature and high shear viscosity (50 ° C., 150 ° C.) is determined based on ASTM D5481, and the kinematic viscosity (40 ° C., 50 ° C., 100 ° C.) is determined based on JIS K 2283. The NOACK evaporation amount was measured based on 5S-41, and the fuel saving property 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 for it (friction torque) was measured with a torque meter. As an engine, an in-line 4-cylinder 2.0L 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).
The test oil temperature was set to 50 ° C., assuming the start of running in a general passenger car and the running state in which the engine oil temperature does not easily rise like an idling stop vehicle and a PHV.

From Table 3, comparison between the same viscosity grade equivalents, that is, comparison of Comparative Example 1, Example 1 and Example 3 as equivalent to 0W-20, and Comparative Example 2, Comparative Example 3 and Example as equivalent to 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. Is understood.

Claims (3)

A lubricating oil composition for an internal combustion engine containing a GTL (gast liquid) base oil synthesized by the Fisher Tropsch method, and the content of the viscosity index improver in the entire lubricating oil composition is 0.1 as the amount of resin. a 20% by weight and, meets the following (a) ~ (I),
A lubricating oil composition for an internal combustion engine, wherein the viscosity index improver is a poly (meth) acrylate which is a comb-shaped polymer.
(A) High temperature and high shear viscosity (HTHSV (ASTM D4683 or ASTM D5481)) at 150 ° C., 10 ⁶ s ^-1 is 1.0 mPa · s or more (B) Dynamic viscosity at 100 ° C. (KV (JIS K2283)) is 3. .0 mm ² / s or more (C) ASTMV 50 ° C./HTHSV150 ° C. is 6.50 or less (D) KV50 ° C./HTHSV150 ° C. is 8.00 or less (E) NOACK evaporation amount (JPI-5S-41) is 15% by mass or less
(F) 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) Contains an imide-based succinimide-based dispersant and / or a boron-modified imide-based succinimide-based dispersant, and in terms of nitrogen concentration, 0.01 to 0.20% by mass (based on the total amount of the lubricating oil composition). be.
(H) ZnDTP is contained in an amount of 0.03 to 0.09% by mass (based on the total amount of the lubricating oil composition) in terms of phosphorus concentration.
(I) The 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. 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 The internal combustion engine according to claim 1, wherein the fraction of the entire oil composition is 50% by mass or less, and the distillate of the entire base oil at 380 ° C. or lower in gas chromatodistillation by ASTM D2887 is 10% by mass or less. Lubricating oil composition. The lubricating oil composition for an internal combustion engine according to claim 1 or 2 , which comprises at least one selected from a corrosion inhibitor, a phenol-based antioxidant, an amine-based antioxidant, and a sulfur-containing additive.