JP2017119787A - Lubricating oil composition for diesel engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lubricating oil composition for a diesel engine, having excellent vaporizability, engine cleaning performance and fuel-saving performance, in an automobile engine oil.SOLUTION: The lubricating oil composition for a diesel engine is provided that contains: GTL (Gas To Liquid) base oil having a kinetic viscosity at 100°C of 4.5-5.5 mm/s; a comb-shaped PMA (polymethacrylate)-based viscosity index improver; and a boron-containing dispersant and/or a boron-containing cleaning agent, the content of the total of the boron-containing dispersant and/or the boron-containing cleaning agent being 0.025 mass% or more with respect to the total amount of the composition in terms of the boron content, and the lubricating oil composition for a diesel engine satisfying 0 W-30 or 5 W-30 according to SAE J300 specification.SELECTED DRAWING: None

Description

  The present invention relates to an engine oil for automobiles (a lubricating oil composition for an internal combustion engine), and more particularly to a lubricating oil composition for a diesel engine excellent in fuel efficiency, oil consumption suppression, and cleanliness.

  The problem with the crankcase lubricating oil is that the lubricating oil can easily escape from the crankcase by so-called blow-by gas. Blowby gas or such a gas / lubricant mixture is preferably recycled to the engine rather than vented to the atmosphere. In some engines, such recirculation is performed by injecting blow-by gas into the engine's air intake system so that the lubricant burns in the piston chamber. While blow-by gas recirculation solves the emissions problem, problems such as the formation of deposits in the air intake system can occur. For example, if deposits are generated in the air compressor, such a compressor will not work well and is more susceptible to damage. Also, for example, if an air cooler exists between the compressor and the cylinder block-crankcase, the air cooler may be contaminated. It has been desired to provide a diesel engine system that prevents or further reduces the formation of such deposits. (Patent Document 1)

  On the other hand, low fuel consumption performance is required. In order to achieve low fuel consumption performance, use a friction modifier that contributes to friction reduction performance, reduce stirring resistance, have low viscosity at low temperature, and improve viscosity index to ensure oil film at high temperature It has been studied to prepare a composition having proper viscosity characteristics using an agent. (Patent Document 2)

Japanese Patent No. 5501620 JP 2014-210844 A

  However, there is still no satisfactory satisfaction in suppressing the formation of deposits, exhibiting fuel saving performance, and maintaining the performance for a long period of time. Also, in the future, it is considered that downsizing and supercharging will continue to increase even in commercial vehicles equipped with diesel engines, and it is expected that the thermal load on engine oil will increase, but in conventional lubricating oil compositions, There was a problem that excellent evaporability could not be obtained.

  Then, this invention makes it a subject to provide the lubricating oil composition for diesel engines which has the outstanding evaporability, engine clean performance, and fuel-saving performance in the engine oil for motor vehicles.

  As a result of the diligent research conducted by the present inventors, a specific base oil, a specific viscosity index improver, a specific dispersant and a detergent are blended, and the specific viscosity grade is satisfied. The present inventors have found that the problem can be solved and completed the present invention. That is, the present invention is as follows.

The present invention (I)
a) a GTL base oil having a kinematic viscosity at 100 ° C. of 4.5 to 5.5 mm ² / s;
b) Comb-shaped PMA (polymethacrylate) viscosity index improver;
c) containing 0.025% by mass or more of a boron-containing dispersant and / or a boron-containing detergent with respect to the total amount of the composition in terms of boron content (total value),
d) A lubricating oil composition for diesel engines characterized by satisfying 0W-30 or 5W-30 in accordance with SAE J300 regulations.
The present invention (II)
e) Amount of polymer containing non-comb PMA (polymethacrylate) viscosity index improver, SCP (styrene diene copolymer) viscosity index improver and / or OCP (olefin copolymer) viscosity index improver, and without diluent As described above, the lubricating oil composition for diesel engines according to the invention (I) satisfies at least one of the following (1) to (3).
(1) Non-comb PMA viscosity index improver content / total viscosity index improver (polymer having a weight average molecular weight of 50,000 or more) content: 0.7 or less (2) OCP viscosity index improver content / Overall viscosity index improver (polymer having a weight average molecular weight of 50,000 or more) Content: 0.2 or less (3) SCP-based viscosity index improver content / Overall viscosity index improver (weight average molecular weight is 5) Polymer) content: 0.3 or less The present invention (III)
f) The lubricating oil composition for diesel engines according to the invention (I) or (II), which satisfies the following viscosity characteristics.
(HTHS 100 ° C. viscosity (capillary method) −HTHS 100 ° C. viscosity (TBS method)) / HTHS 100 ° C. viscosity (TBS method): 0.07 to 0.15

  ADVANTAGE OF THE INVENTION According to this invention, in the engine oil for motor vehicles, it becomes possible to provide the lubricating oil composition for diesel engines which has the outstanding evaporability, engine cleaning performance, and fuel-saving performance.

  Hereinafter, although the component (component), composition (component content), and physical properties of the lubricating oil composition for diesel engines according to the present invention will be described in detail, the present invention is not limited to these.

≪Ingredients≫
The lubricating oil composition according to the present embodiment comprises a GTL base oil as a base oil, a comb PMA viscosity index improver, a boron-containing dispersant and / or a boron-containing detergent, and other components as necessary. contains.

(Base oil)
As the base oil of the lubricating oil composition according to the present embodiment, GTL (gas-liquid) oil synthesized by the Fischer-Tropsch method of natural gas liquid fuel technology is used. By using such a base oil, it is possible to improve oxidation stability and reduce evaporation loss in the system of the present invention.

  When comb polymers are used, compared to Yubase base oil, especially in the system of the present invention, GTL base oil reduces the temporary shear viscosity at 100 ° C, contributing to improved fuel economy. Can do.

In particular, in the present invention, a GTL base oil having a kinematic viscosity at 100 ° C. of 4.5 to 5.5 mm ² / s is used. When the kinematic viscosity at 100 ° C. of the base oil is less than 4.5, sufficient evaporability cannot be obtained. Further, if the kinematic viscosity at 100 ° C. exceeds 5.5, sufficient fuel efficiency cannot be obtained.

Here, the kinematic viscosity at 100 ° C. in order to obtain the base oil is a 4.5~5.5mm ² / s, the kinematic viscosity at 100 ° C. has a single a 4.5~5.5mm ² / s Although GTL base oils are preferred, when preparing, GTL base oil kinematic viscosity at 100 ° C. is 3.0~6.0mm ² / s and (a1), 100 ° C. kinematic viscosity 7.0~13mm ² / s It is preferable to mix two kinds of the GTL base oil (a2). When the 100 ° C. kinematic viscosity of the low-viscosity base oil component (a1) is less than 3.0 mm ² / s, the amount of evaporation increases, making it difficult to maintain the viscosity of the composition over a long period of time. On the other hand, if a high viscosity base oil component (a2) having a kinematic viscosity at 100 ° C. exceeding 13 mm ² / s is used, the viscosity at low temperature −40 ° C. is increased and the startability at low temperature is deteriorated. Furthermore, in this case, the viscosity index of the mixed GTL base oil is preferably 120 to 180, and more preferably 120 to 150.

  These GTL base oils typically have a total sulfur content of less than 10 ppm and more preferably a total nitrogen content of less than 1 ppm. An example of such a GTL base oil product is SHELL XHVI®.

(Cleaning agent)
The lubricating oil composition according to this embodiment may contain a boron-containing detergent as a detergent. Boron-containing detergents include, but are not limited to, boric acid-containing alkaline earth metal salts, and more specifically, borated alkaline earth metal alkyl salicylate detergents and borated alkaline earth metal alkyltoluenes. A sulfonate detergent is mentioned, and it is preferable that it is a calcium borate alkyltoluene sulfonate. In addition, what is necessary is just to use a well-known thing as such a boron containing detergent (For example, a borated alkaline-earth metal alkyltoluenesulfonate detergent can be manufactured in accordance with the method described in Unexamined-Japanese-Patent No. 2008-297547. ).

  Here, the lubricating oil composition according to the present embodiment may contain other detergent (for example, a metallic detergent) as long as the effects of the present invention are not impaired. Examples of metal detergents include alkaline earth metal sulfonates, alkaline earth metal phenates, alkaline earth metal salicylates, alkaline earth metal naphthenates, and the like. Examples of the alkaline earth metal include calcium and magnesium. These can be used alone or in combination of two or more. Usually, calcium or magnesium sulfonates, phenates and salicylates are preferably used. Alkaline earth metal phenates include alkylphenols having a linear or branched alkyl group having 4 to 30, preferably 6 to 18 carbon atoms, alkylphenol sulfides, alkaline earth metal salts of alkylphenol Mannich reactants, especially calcium A salt is preferably used. Alkaline earth salicylates include alkaline earth metal salts of alkylsalicylic acid having a linear or branched alkyl group having 1 to 30 carbon atoms, preferably 6 to 18, particularly preferably magnesium salts and / or calcium salts. Preferably used. These base numbers can be arbitrarily selected depending on the type and purpose of the lubricating oil to be applied.

(Dispersant)
The lubricating oil composition according to this embodiment may contain a boron-containing dispersant as a dispersant. The boron-containing dispersant is, for example, a boronated dispersant such as polybutenyl succinimide, polybutenyl succinamide, benzylamine, and succinate.

  Polybutenyl succinimide is obtained from polybutene obtained by polymerizing high-purity isobutene or a mixture of 1-butene and isobutene with a boron fluoride catalyst or an aluminum chloride catalyst, and has a vinylidene structure at the end of polybutene. What it has is contained normally 5-100 mol%. The polyalkylene polyamine chain preferably contains 2 to 5, particularly 3 to 4 nitrogen atoms from the viewpoint of obtaining an excellent sludge inhibiting effect. In addition, as a derivative of polybutenyl succinimide, a boric acid compound such as boric acid or an oxygen-containing organic compound such as alcohol, aldehyde, ketone, alkylphenol, cyclic carbonate, or organic acid is added to the polybutenyl succinimide. It can be used as a so-called modified succinimide in which a part or all of the remaining amino group and / or imino group is neutralized or amidated by acting.

  In addition, the lubricating oil composition according to the present embodiment only needs to include at least one of the boron-containing detergent and the boron-containing dispersant described above, and includes only the boron-containing detergent, only the boron-containing dispersant. Any embodiment comprising both a boron-containing detergent and a boron-containing dispersant is within the scope of the present invention.

(Antiwear agent)
Examples of the antiwear agent that imparts wear resistance and extreme pressure that can be used in the lubricating oil composition according to this embodiment include zinc dithiophosphate (ZnDTP). Examples of ZnDTP generally include zinc dialkyldithiophosphate, zinc diaryldithiophosphate, zinc arylalkyldithiophosphate, and the like. These alkyl groups may be linear or branched. For example, the zinc group of zinc dialkyldithiophosphate is a zinc dialkyldithiophosphate having an alkylaryl group substituted with a primary or secondary alkyl group having 3 to 22 carbon atoms or an alkyl group having 3 to 18 carbon atoms. used. Specific examples of zinc dialkyldithiophosphate include zinc dipropyldithiophosphate, zinc dibutyldithiophosphate, zinc dipentyldithiophosphate, zinc dihexyldithiophosphate, zinc diisopentyldithiophosphate, zinc diethylhexyldithiophosphate, zinc dioctyldithiophosphate, Zinc nonyldithiophosphate, zinc didecyldithiophosphate, zinc didodecyldithiophosphate, zinc dipropylphenyldithiophosphate, zinc dipentylphenyldithiophosphate, zinc dipropylmethylphenyldithiophosphate, zinc dinonylphenyldithiophosphate, didodecylphenyldithiophosphate Zinc, zinc dodecylphenyl dithiophosphate, and the like can be mentioned.

(Metal deactivator)
Metal deactivators that can be used in the lubricating oil composition according to this embodiment include benzotriazole derivatives such as benzotriazole and alkyl-tolutriazole, and benzimidazole derivatives such as benzimidazoles and toluimidazoles. Examples thereof include indazole derivatives such as toluindazoles, benzothiazole derivatives such as benzothiazoles and torzothiazoles, and the like. Furthermore, a benzoxazole derivative, a thiadiazole derivative, a triazole derivative, etc. are mentioned.

(Antioxidant)
Examples of the antioxidant that can be used in the lubricating oil composition according to this embodiment include amine-based antioxidants and phenol-based antioxidants. As amine-based antioxidants, p, p′-dioctyl-diphenylamine (manufactured by Seiko Chemical Co., Ltd .: non-flex OD-3), p, p′-di-α-methylbenzyl-diphenylamine, Np-butylphenyl- Dialkyl-diphenylamines such as Np′-octylphenylamine, monoalkyldiphenylamines such as mono-t-butyldiphenylamine and monooctyldiphenylamine, di (2,4-diethylphenyl) amine, di (2-ethyl-4 -Bis (dialkylphenyl) amines such as nonylphenyl) amine, alkylphenyl-1-naphthylamines such as octylphenyl-1-naphthylamine, Nt-dodecylphenyl-1-naphthylamine, 1-naphthylamine, phenyl-1- Naphtylamine, phenyl-2-naphthyla , N-hexylphenyl-2-naphthylamine, aryl-naphthylamines such as N-octylphenyl-2-naphthylamine, N, N′-diisopropyl-p-phenylenediamine, N, N′-diphenyl-p-phenylenediamine, etc. Phenylenediamines, phenothiazines (manufactured by Hodogaya Chemical Co., Ltd .: Phenothiazine), and phenothiazines such as 3,7-dioctylphenothiazine. Examples of phenolic antioxidants include 2-t-butylphenol, 2-t-butyl-4-methylphenol, 2-t-butyl-5-methylphenol, 2,4-di-t-butylphenol, 2,4- Dimethyl-6-t-butylphenol, 2-t-butyl-4-methoxyphenol, 3-t-butyl-4-methoxyphenol, 2,5-di-t-butylhydroquinone (manufactured by Kawaguchi Chemical Co., Ltd .: Antage DBH), 2,6-di-t-butylphenol such as 2,6-di-t-butylphenol, 2,6-di-t-butyl-4-methylphenol, 2,6-di-t-butyl-4-ethylphenol 2,6-di-tert-butyl-4-, such as -4-alkylphenols, 2,6-di-tert-butyl-4-methoxyphenol, 2,6-di-tert-butyl-4-ethoxyphenol There is a Turkey alkoxy phenols. 3,5-di-t-butyl-4-hydroxybenzyl mercapto-octyl acetate, n-octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate (manufactured by Yoshitomi Pharmaceutical Co., Ltd.) Yoshinox SS), n-dodecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2'-ethylhexyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) ) Alkyl-3- () such as propionate, benzenepropanoic acid 3,5-bis (1,1-dimethyl-ethyl) -4-hydroxy-C7-C9 side chain alkyl ester (manufactured by Ciba Specialty Chemicals: Irganox L135) 3,5-di-t-butyl-4-hydroxyphenyl) propionates, 2,6-di-t-butyl-α-di Tylamino-p-cresol, 2,2′-methylenebis (4-methyl-6-t-butylphenol) (manufactured by Kawaguchi Chemical Co .: Antage W-400), 2,2′-methylenebis (4-ethyl-6-t-) And 2,2′-methylenebis (4-alkyl-6-t-butylphenol) such as (Butylphenol) (manufactured by Kawaguchi Chemical Co., Ltd .: Antage W-500). Further, 4,4′-butylidenebis (3-methyl-6-tert-butylphenol) (manufactured by Kawaguchi Chemical Co., Ltd .: Antage W-300), 4,4′-methylenebis (2,6-di-tert-butylphenol) (shell) -Japan company make: Ionox220AH), 4,4'-bis (2,6-di-t-butylphenol), 2, 2- (di-p-hydroxyphenyl) propane (shell Japan company make: bisphenol A), 2,2-bis (3,5-di-t-butyl-4-hydroxyphenyl) propane, 4,4′-cyclohexylidenebis (2,6-t-butylphenol), hexamethylene glycol bis [3- ( 3,5-di-t-butyl-4-hydroxyphenyl) propionate] (manufactured by Ciba Specialty Chemicals: Irganox L109), triethyle Glycol bis [3- (3-t-butyl-4-hydroxy-5-methylphenyl) propionate] (manufactured by Yoshitomi Pharmaceutical Co., Ltd .: Tominox 917), 2,2′-thio- [diethyl-3- (3 5-di-t-butyl-4-hydroxyphenyl) propionate] (manufactured by Ciba Specialty Chemicals: Irganox L115), 3,9-bis {1,1-dimethyl-2- [3- (3-t-butyl -4-hydroxy-5-methylphenyl) propionyloxy] ethyl} 2,4,8,10-tetraoxaspiro [5,5] undecane (Sumitomo Chemical: Sumilizer GA80), 4,4'-thiobis (3-methyl -6-t-butylphenol) (manufactured by Kawaguchi Chemical Co., Ltd .: Antage RC), 2,2'-thiobis (4,6-di-t-butyl-resorcin) There is Lumpur class. Tetrakis [methylene-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] methane (manufactured by Ciba Specialty Chemicals: Irganox L101), 1,1,3-tris (2-methyl) -4-hydroxy-5-t-butylphenyl) butane (Yoshitomi Pharmaceutical Co., Ltd .: Yoshinox 930), 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4 -Hydroxybenzyl) benzene (manufactured by Shell Japan: Ionox 330), bis- [3,3′-bis- (4′-hydroxy-3′-t-butylphenyl) butyric acid] glycol ester, 2- (3 ', 5'-di-tert-butyl-4-hydroxyphenyl) methyl-4- (2 ", 4" -di-tert-butyl-3 "-hydroxyphenyl) methyl Of polyphenols such as -6-tert-butylphenol, 2,6-bis (2'-hydroxy-3'-tert-butyl-5'-methyl-benzyl) -4-methylphenol, pt-butylphenol and formaldehyde Examples include condensates and phenol aldehyde condensates such as a condensate of pt-butylphenol and acetaldehyde.

(Viscosity index improver)
The lubricating oil composition according to the present embodiment contains a comb polymethacrylate viscosity index improver. The comb polymer represents a polymer having a plurality of extended side chains in a comb shape with respect to the polymer main chain. Among these comb polymers, the viscosity index improver according to this embodiment includes a comb polymethacrylate polymer as a viscosity index improver. In the present invention, the “viscosity index improver” refers to a polymer having a weight average molecular weight of 50,000 or more.

  As the comb polymethacrylate viscosity index improver according to the present embodiment, for example, a polymer described in JP 2010-532805 may be appropriately used.

  Further, the comb-shaped polymethacrylate viscosity index improver according to this embodiment preferably has a weight average molecular weight of 200 to 600,000, more preferably 25 to 500,000, and 300 to 450,000. Most preferably. Further, it is preferable that the PSSI (Permanent Siability Index) is 10 or less.

  Specific examples of such comb-shaped polymethacrylate viscosity index improvers include Viscoplex 3-201 (registered trademark) and Viscoplex 3-220 (registered trademark).

  Moreover, the lubricating oil composition according to the present embodiment may contain a viscosity index improver other than the comb polymethacrylate viscosity index improver. One example of such a viscosity index improver is one or more polymers selected from the group consisting of non-comb PMA (polymethacrylate), OCP (olefin copolymer) and SCP (styrene diene copolymer).

  The non-comb PMA (polymethacrylate) viscosity index improver is not particularly limited and may be a known one, but it is preferable that the weight average molecular weight is 100,000 to 400,000. Specific examples of such PMA include those described in JP-A-2014-1255569.

  The OCP (olefin copolymer) viscosity index improver is not particularly limited, and a known one can be used, but a weight average molecular weight of 50,000 to 300,000 is preferable. Specific examples of such OCPs include those described in Japanese Patent Application Laid-Open No. 2014-125569.

  The SCP (styrene diene copolymer) viscosity index improver is not particularly limited, and any known one can be used, but the weight average molecular weight is preferably 200,000 to 1,000,000. Specific examples of such SCP include Infineum (registered trademark) SV150.

  The lubricating oil composition according to this embodiment may contain a comb polymer other than comb polymethacrylate as a viscosity index improver.

  Such a viscosity index improver (a polymer having a weight average molecular weight of 50,000 or more) is generally blended in an appropriate liquid medium in order to facilitate handling.

(Defoamer)
Examples of the antifoaming agent that can be used in the lubricating oil composition according to the present embodiment include organosilicates such as dimethylpolysiloxane, diethyl silicate, and fluorosilicone, and non-silicone antifoaming agents such as polyalkyl acrylate. .

≪Composition≫
(Amount of base oil)
The content of the base oil is preferably 60 to 90% by mass, more preferably 65 to 90% by mass, and 70 to 85% by mass based on the total mass of the lubricating oil composition. More preferably, it is in the range.

(Content of viscosity index improver)
The content of the viscosity index improver (total viscosity index improver content) is not particularly limited and can be appropriately changed. For example, 0.05 to 20% by mass based on the total mass of the lubricating oil composition And so on. Hereinafter, the preferable content of each viscosity index improver will be described in detail.

・ Comb PMA
The content of the comb PMA is not particularly limited, but is preferably 1.0 to 6.0% by mass based on the total mass of the lubricating oil composition, based on the total mass of the lubricating oil composition. It is more preferably 1.0 to 5.0% by mass, and still more preferably 1.0 to 4.0% by mass.

・ Non-comb PMA
The content of the non-comb PMA is preferably such that the non-comb PMA content / total viscosity index improver content is 0.7 or less.

・ OCP
The OCP content is preferably such that the OCP content / total viscosity index improver content is 0.2 or less.

・ SCP
The SCP content is preferably such that the SCP content / total viscosity index improver content is 0.3 or less.

  Viscosity index improvers include non-comb PMA (polymethacrylate), SCP (styrene diene copolymer) and / or OCP (olefin copolymer), and at least one (preferably all) of the above ranges. When satisfying, in the system of the present invention, the production cost can be reduced while the effects of the present invention are exhibited.

(Boron-containing detergent and boron-containing dispersant)
In order to obtain a desired effect, the content of the boron-containing detergent and the boron-containing dispersant needs to be 0.025% by mass or more based on the total amount of the composition as a boron-containing conversion value (total value). In addition, although an upper limit is not specifically limited, For example, what is necessary is just to be 0.1 mass% or less (preferably 0.050 mass% or less) etc.

(Amounts of other components in the lubricating oil composition)
The preferred addition amount of other components that may be added to the lubricating oil composition according to this embodiment will be described. First, the preferred addition amount of the antioxidant is in the range of 0.01 to 2% by mass based on the total mass of the lubricating oil composition, alone or in combination. A suitable addition amount of the metal deactivator is in the range of 0.01 to 0.5% by mass based on the total mass of the lubricating oil composition, alone or in combination. The preferred addition amount of the antiwear agent (eg, ZnDTP) is, for example, 0.01 to 0.10% by mass, more preferably, as a phosphorus (P) amount based on the total mass of the lubricating oil composition, alone or in combination. Is in the range of 0.05 to 0.08 mass%. A suitable addition amount of the antifoaming agent is, for example, in the range of 0.0001 to 0.01% by mass based on the total mass of the lubricating oil composition, alone or in combination. A suitable addition amount of the metal-based detergent is, for example, 0.05 to 0.3% by mass, more preferably 0.1 to 0 by metal amount based on the total mass of the lubricating oil composition, alone or in combination. .2% by mass. The preferred addition amount of the ashless dispersant is an amount that provides, for example, 0.01 to 0.3% by mass of nitrogen, alone or in combination, based on the total mass of the lubricating oil composition.

≪Physical properties≫
(Capillary viscosity / TBS viscosity)
Here, it is considered that there is an excellent correlation between the HTHS viscosity at 100 ° C. and the fuel consumption characteristics. There are also various methods for measuring HTHS viscosity. Especially, the viscosity obtained by the HTHS viscosity measured by the Capillary method and the viscosity measured by the TBS method may differ depending on the type of the viscosity index improver used. Under such circumstances, the larger the value of Equation 1 below, the larger the viscosity measured by a method using a capillary viscometer (Capillary), and the smaller the viscosity measured using a rotational viscometer (TBS). , Indicating that the difference becomes large. In this case, the shear viscosity of the oil is reduced at a portion that slides in a state close to a rotational viscometer, such as between the crankshaft and the bearing. That is, it is considered that the viscous resistance can be reduced and the friction loss can be reduced at the above portion. On the other hand, at a portion where the oil is sheared in a state close to a capillary viscometer, a high shear viscosity can be maintained and sufficient durability can be maintained.

(Capillary viscosity−TBS viscosity) / TBS viscosity (Formula 1)

  In the lubricating oil composition according to this embodiment, it was found that [(Capillary viscosity−TBS viscosity) / TBS viscosity] satisfies 0.07 to 0.15, and low fuel consumption is realized in correlation therewith. .

Here, the method for measuring the Capillary viscosity is a value measured based on the ASTM D5481 test method (150 ° C.) with the temperature condition set to 100 ° C. (shear rate is 1.0 * 10 ^ 6S ⁻¹ ).

  Moreover, the measuring method of TBS viscosity is the value measured by the method described in patent 5565999.

  EXAMPLES Next, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited at all by these examples.

<< Raw Materials >> The raw materials used in this example are as follows. The properties of each base oil are shown in Table 1. (Base oil) Base oil-1: XHVI4 (GTL oil) Base oil-2: XHVI8 (GTL oil) Base oil-3: XHVI3 (GTL oil) Base oil-4: Yubase4 (mineral oil) Base oil-5: Yubase8 (Mineral oil) Base oil-6: Yubase3 (mineral oil) (Additive package) DH-2 DI package-1: As shown in the table, in this example, when 14.00% was added, boron in the lubricating oil Content of 0.033 mass% {Including boron-containing dispersant (calcium borate alkyltoluene sulfonate) and boron-containing detergent (boronated succinic acid ester-based dispersant), other additive amounts are DI package-2, 3 Equivalent} DH-2 DI Package-2: As shown in the table, in this example, when 14.00% is added, the boron content of the lubricating oil is 0.027 mass%. Contains boron-containing dispersant (calcium borate alkyltoluene sulfonate) and boron-containing detergent (boronated succinate-based dispersant), the amount of other additives is equivalent to DI package-1, 3} DH-2 DI package -3: As shown in the table, in this example, when 14.00% is added, the boron content of the lubricating oil becomes 0.020 mass% {boron-containing dispersant (calcium borate alkyltoluenesulfonate) and boron content Contains detergent (boronated succinic acid ester-based dispersant), and the amount of other additives is equivalent to DI packages-1 and 2} (viscosity index improver) Viscosity index improver solution-1: Viscoplex 3-220 (comb PMA system) Solution containing viscosity index improver (diluted by about 40%) Viscosity index improver solution-2: Viscoplex 3-201 (comb PMA Solution containing viscosity index improver (diluted about 60%) Viscosity index improver solution-3: Solution containing Viscoplex 6-954 (non-comb PMA viscosity index improver) (diluted about 40%) Viscosity index improver solution- 4: Solution containing Lz7177B (olefin copolymer viscosity index improver) (diluted by about 87.5%) Viscosity index improver solution-5: Solution containing Infineum (registered trademark) SV150 (styrene diene copolymer viscosity index improver) (Dilution of about 93.5%) (antifoaming agent) DCF 3 mass% solution

The said raw material was made into the mixing | blending shown in Table 2 and Table 3, and the lubricating oil composition which concerns on the present Examples 1-8 and Comparative Examples 1-10 was obtained.

≪Evaluation≫
Next, the evaluation test was done about the lubricating oil composition which concerns on Examples 1-8 and Comparative Examples 1-10. In addition, about the lubricating oil composition which concerns on an Example, it was confirmed that all satisfy | fill 5W-30.

(Fuel consumption characteristics)
Fuel efficiency characteristics were evaluated based on a bench fuel economy test using a 4000cc diesel engine manufactured by a Japanese manufacturer. The driving conditions were set with reference to the Ministry of Land, Infrastructure, Transport and Tourism 10.15 mode. The gallery temperature at the time of measurement was set to 90 ° C. In addition, the result shown in Table 2 and Table 3 shows the fuel efficiency improvement rate (%) when the commercially available diesel engine oil classified as 10W-30 in the SAE viscosity grade is used as a reference. In this evaluation, when the fuel efficiency improvement rate (%) is 1.0 or more, the fuel efficiency characteristics are evaluated as ◯.

(Evaporation)
Noack volatility (%) was measured based on ASTM D5800. In this evaluation, when the Noack volatility (%) was 13.0 or less, the evaporability was evaluated as ◯.

(Cleanliness)
A hot tube test was carried out in accordance with the Japan Petroleum Institute Standard JPI-5S-55-99 “Engine Oil-Hot Tube Test Method”. The test conditions were set at a test temperature of 290 ° C./300° C., a test time of 16 hours, a sample oil feed rate of 0.3 ml / hour, and an air flow rate of 10 ml / hour. ) Was 7.0 or more, the cleanliness was evaluated as ◯.

([(Capillary viscosity−TBS viscosity) / TBS viscosity])
[(Capillary viscosity−TBS viscosity) / TBS viscosity] was calculated according to the method described above.

  Furthermore, in each Example and Comparative Example, kinematic viscosity (40 ° C.), kinematic viscosity (100 ° C.), viscosity index (VI), boron content (calculated value), calcium content (calculated value), phosphorus content (calculated value) The amount of zinc (calculated value), the amount of nitrogen (calculated value), and the amount of molybdenum (calculated value) were calculated (Base stock Vk 100 ° C. is the kinematic viscosity of the mixed base oil 100 ° C.).

Claims (3)

a) a GTL base oil having a kinematic viscosity at 100 ° C. of 4.5 to 5.5 mm ² / s;
b) Comb-shaped PMA (polymethacrylate) viscosity index improver;
c) containing a boron-containing dispersant and / or a boron-containing detergent,
d) The total content of the boron-containing dispersant and / or the boron-containing detergent is 0.025% by mass or more based on the total amount of the composition in terms of boron content,
e) A diesel engine lubricating oil composition characterized by satisfying 0W-30 or 5W-30 in accordance with SAE J300 regulations. e) a non-comb PMA (polymethacrylate) viscosity index improver, an SCP (styrene diene copolymer) viscosity index improver and / or an OCP (olefin copolymer) viscosity index improver, and the following (1) to The lubricating oil composition for a diesel engine according to claim 1, satisfying at least one of (3).
(1) Non-comb PMA viscosity index improver content / total viscosity index improver content: 0.7 or less (2) OCP viscosity index improver content / total viscosity index improver content: 0. 2 or less (3) SCP viscosity index improver content / total viscosity index improver content: 0.3 or less f) The lubricating oil composition for diesel engines according to claim 1 or 2, which satisfies the following viscosity characteristics.
(HTHS 100 ° C. viscosity (capillary method) −HTHS 100 ° C. viscosity (TBS method)) / HTHS 100 ° C. viscosity (TBS method): 0.07 to 0.15