JP4559550B2 - Lubricating oil composition for internal combustion engines - Google Patents

Description

【００１２】
一般式（Ｉ）において、Ｒ¹ 〜Ｒ⁴ はそれぞれ同一でも異なっていてもよい炭素数２〜２０、好ましくは３〜１０の直鎖状又は分岐鎖状のアルキル基を示す。
具体的には、エチル基，ｎ−プロピル基，イソプロピル基，ｎ−ブチル基，イソブチル基，ｓｅｃ−ブチル基，ｔｅｒｔ−ブチル基，各種ペンチル基，各種ヘキシル基，各種ヘプチル基，各種オクチル基，各種ノニル基，各種デシル基，各種ウンデシル基，各種ドデシル，各種トリデシル基，各種テトラデシル基，各種ペンタデシル基，各種ヘキサデシル基，各種ヘプタデシル基，各種オクタデシル基，各種ノナデシル基，各種エイコシル基を挙げることができる。なお、Ｒ¹ 〜Ｒ⁴ を導入する際にα−オレフィンの混合物を原料とする場合があるが、その場合（ａ）成分としては異なる構造のアルキル基を有するＺｎＤＴＰの混合物となる。
【００１３】
（ａ）成分は、一種あるいは二種以上組み合わせて使用することができ、その配合量は、組成物全量基準で、リン（Ｐ）量として０．０２〜０．１５重量％である。０．０２重量％未満であると、摩擦低減効果及び高温における酸化安定性改善効果が十分に発揮されない場合がある。０．１５重量％を超えると、その量に見合った効果の向上が認められない場合がある。好ましくは、０．０５〜０．１０重量％の範囲である。
【００１４】
（ｂ）成分
特公平３−２２４３８号公報に記載の硫黄含有モリブデン錯体である。即ち、コハク酸イミド、カルボン酸アミド及びマンニッヒ塩基からなる群から選ばれる塩基性窒素化合物と三酸化モリブデンとを反応させて得られるモリブデン錯体に、さらに硫黄又はチオアセトアミドを反応させて得られる油溶性の硫黄含有モリブデン錯体である。
【００１５】
特公平３−２２４３８号公報の要点を纏めると下記の通りである。
（１）コハク酸イミドとして、炭素数７０〜１２８のポリイソブテニル無水コハク酸と、テトラエチレンペンタミン，トリエチレンテトラミンなどのポリアミンとの反応生成物が好適に使用される。
（２）カルボン酸アミドとして、炭素数１３〜２１の脂肪酸又はこの脂肪酸と、ポリイソブテニル基の炭素数が７２〜１２８であるポリイソブテニルカルボン酸との混合物と、トリエチレンテトラミン，テトラエチレンペンタミンなどのポリアミンとの反応生成物が好適に使用される。
（３）マンニッヒ塩基として、フェノール又は炭素数９〜２００のアルキル置換フェノールと、ホルムアルデヒド又はパラホルムアルデヒドと、メチルアミンなどのアルキルアミン、又はジエチレントリアミン，テトラエチレンペンタミンなどのポリアミンとの反応生成物が好適に使用される。
【００１６】
（４）塩基性窒素化合物と三酸化モリブデンとの反応には、触媒として、水やエチレングリコール、希釈剤として、潤滑油、炭化水素溶剤が好適に使用される。
（５）塩基性窒素化合物と三酸化モリブデンとの反応は、混合物の融点から還流温度の間で、大気圧前後の圧力で行う。
（６）塩基性窒素化合物と三酸化モリブデンとの反応生成物中には、通常、塩基性窒素原子１個当たり０．０１〜２個のモリブデン原子を含むようにする。
（７）最終生成物である硫黄含有モリブデン錯体中には、モリブデン原子１個当たり０．１〜４個の硫黄原子を含むようにする。
【００１７】
（ｂ）成分は、一種あるいは二種以上組み合わせて使用することができ、その配合量は、組成物全量基準で、モリブデン（Ｍｏ）量として２０〜１００重量ｐｐｍである。２０重量ｐｐｍ未満であると、高温における酸化安定性改善効果が十分に発揮されない場合がある。１００重量ｐｐｍを超えると、その量に見合った効果の向上が認められない場合がある。好ましくは、４０〜８０重量ｐｐｍの範囲である。
【００１８】
（ｃ）成分
ジチオカルバミン酸モリブデン（以下、ＭｏＤＴＣという）は下記一般式（II）で表される。
【００１９】
【化２】

【００２０】
一般式（ＩＩ）において、Ｒ⁵〜Ｒ⁸は炭素数５〜１６の炭化水素基であり、全て同一でも異なっていてもよい。ＸはＳ（硫黄原子）又はＯ（酸素原子）である。Ｒ⁵〜Ｒ⁸で表される炭化水素基としては、例えば、炭素数５〜１６のアルキル基、炭素数５〜１６のアルケニル基、炭素数５〜１６のシクロアルキル基、炭素数５〜１６のアルキルアリール基、炭素数５〜１６のアリールアルキル基などを挙げることができる。炭素数５〜１６の炭化水素の具体例としては、各種ペンチル基，各種ヘキシル基，各種ヘプチル基，各種オクチル基，各種ノニル基，各種デシル基，各種ウンデシル基，各種ドデシル基，各種トリデシル基，各種テトラデシル基，各種ペンタデシル基，各種ヘキサデシル基，各種オクテニル基，各種ノネニル基，各種デセニル基，各種ウンデセニル基，各種ドデセニル基，各種トリデセニル基，各種テトラデセニル基，各種ペンタデセニル基，シクロヘキシル基，ジメチルシクロヘキシル基，エチルシクロヘキシル基，メチルシクロヘキシルメチル基，シクロヘキシルエチル基，プロピルシクロヘキシル基，ブチルシクロヘキシル基，ヘプチルシクロヘキシル基，フェニル基，トリル基，ジメチルフェニル基，ブチルフェニル基，ノニルフェニル基，メチルベンジル基，フェニルエチル基，ナフチル基，ジメチルナフチル基などを挙げることができる。
【００２５】
（ｃ）成分は、一種あるいは二種以上組み合わせて使用することができ、その配合量は、組成物全量基準で、モリブデン（Ｍｏ）量として０．０１〜０．１５重量％である。０．０１重量％未満であると、摩擦低減効果及び高温における酸化安定性改善効果が十分に発揮されない場合がある。０．１５重量％を超えると、その量に見合った効果の向上が認められない。好ましくは、０．０３〜０．１０重量％の範囲である。
【００２６】
さらに、本発明の潤滑油組成物には、通常潤滑油の物性向上のために、本発明の目的が損なわれない範囲で、従来から潤滑油に慣用されている各種添加剤、例えば、アルカリ土類金属のスルホネート，フェネート，サリチレート等の金属系清浄剤、コハク酸イミド，コハク酸エステル等の無灰系分散剤、フェノール系，アミン系，硫黄系等の酸化防止剤、ジスルフィド類等の極圧剤、多価アルコール部分エステル，アミン，アミド等の摩擦調整剤、ポリメタクリレート，オレフィンコポリマー等の粘度指数向上剤、塩素化パラフィン−ナフタリン縮合物，ポリメタクリレート，ポリアクリレート，ポリアルキルスチレン等の流動点降下剤、ベンゾトリアゾール，チアジアゾール等の金属不活性化剤、アルケニルコハク酸やその部分エステル，ポリアルキレンエーテル，ポリアルキレンアルキルフェニルエーテル等の防錆剤、シリコーン油等の消泡剤などを、組成物全量基準で、（ａ）〜（ｃ）成分以外の添加剤全部で、３〜１０重量％の範囲で配合することができる。
【００２７】
【実施例】
次に、本発明を実施例によりさらに詳しく説明するが、本発明はこれらの例によってなんら限定されるものではない。
実施例１〜６、比較例１〜４及び参考例１〜３
下記の基油に、下記の添加剤を第１表及び第２表に示す割合で配合し、実施例と比較例、並びに参考例の潤滑油組成物を得た。その潤滑油組成物について、下記に示す方法で高温酸化安定性、摩擦係数について評価し、その結果を第１表（実施例、参考例）、第２表（比較例）に示す。
（１）基油
・ＰＡＯ（１−デセンの二量体の水素化物：１００℃における動粘度６．０ｍｍ²／ｓ、％ＣＡ＝０、実施例１）
・鉱油１（パラフィン系鉱油：１００℃における動粘度４．２ｍｍ²／ｓ、％ＣＡ＝０、実施例２〜６、比較例２〜４、参考例２，３）
・鉱油２（パラフィン系鉱油：１００℃における動粘度４．３ｍｍ²／ｓ、％ＣＡ＝５．０、参考例１）
・鉱油３（パラフィン系鉱油：１００℃における動粘度４．１ｍｍ²／ｓ、％ＣＡ＝７．６、比較例１）
【００２８】
（２）添加剤
（ａ）成分
・ＺｎＤＴＰ（Ｚｎ含量９．０重量％、Ｐ含量７．８重量％、Ｓ含量１５．０重量％、アルキル基は第２級で炭素数３及び６のものと、第１級で炭素数８のものがある、実施例１〜６、比較例１〜３、参考例１〜３）
（ｂ）成分
・硫黄含有Ｍｏ錯体（特公平３−２２４３８号公報の実施例１に準拠して調製、Ｍｏ含量６．３重量％、Ｓ含量２．２重量％、実施例１〜６、比較例１，３，４、参考例１〜３）
（ｃ）成分
・ＭｏＤＴＣ（Ｍｏ含量４．５重量％、Ｓ含量５．７重量％、アルキル基の炭素数８〜１３、実施例１〜６、比較例１，２，４、参考例１）
・ＭｏＤＴＰ（ジチオリン酸モリブデン：Ｍｏ含量９．０重量％、Ｐ含量３．３重量％、Ｓ含量９．９重量％、アルキル基の炭素数８、参考例２）
・Ｍｏアミン塩（モリブデン酸のアミン塩：Ｍｏ含量４．５重量％、参考例３）
【００２９】
（３）評価方法
（ｉ）摩擦係数（μ）
ブロック オン リング試験機（ＬＦＷ−１）で回転数１，４００ｒｐｍ、荷重２０ｌｂｓ、油温８０℃、時間１５分、リングの半分が試料油に浸漬する油量でテストブロックにＦａｌｅｘ社製Ｈ−６０テストブロック、テストリングにＦａｌｅｘ社製Ｓ−１０テストリングを用いてブロックに荷重をかけ、リングを回転させたときに生じる抵抗を歪み計で検出し、摩擦係数を算出した。
（ii）高温酸化安定性
ＡＳＴＭ Ｄ−４７４２（ＴＦＯＵＴ）に準拠して、下記の評価条件で酸化誘導時間（分）を測定した。
（評価条件）
試験温度：１６０℃、酸素圧：６２０ｋＰａ、試料油：１．５ｇ、
触媒：ＳＲＭ１８１７ｃ、水量：試料油に対し２重量％、燃料触媒量：試料油に対して４重量％、金属触媒量：試料油に対して４重量％
【００３０】
【表１】

【００３１】
【表２】

【００３２】
【表３】

【００３３】
【表４】

【００３４】
【発明の効果】
本発明の内燃機関用潤滑油組成物は、高温条件下で長時間の酸化寿命を有し、かつ優れた低燃費性能を有するものであり、特にエンジン油として実用的である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lubricating oil composition for an internal combustion engine, and more particularly, is suitable as a lubricating oil for a gasoline engine, has a long oxidation life under high temperature conditions, and has excellent fuel efficiency. The present invention relates to a lubricating oil composition.
[0002]
[Prior art]
In response to energy / environmental problems, it is essential to have a fuel efficiency improvement effect for lubricating oils for internal combustion engines. Recently, long drainage has been added to the required performance to address environmental problems. The lubricating oil for internal combustion engines is required to have a high level of lubricating performance.
[0003]
From the above background, friction modifiers such as organic molybdenum compounds are used in lubricating oils for internal combustion engines such as automobiles for the purpose of imparting a fuel efficiency improvement effect. However, recent improvements in automobile technology have led to higher engine output and higher rotation speed, and the use in severe conditions has led to demand for oxidation stability under high temperature conditions.
[0004]
Japanese Examined Patent Publication No. 3-22438 discloses an engine oil having improved oxidation stability at high temperature by combining a sulfur-containing molybdenum complex and diphenylamine, but has not yet provided an effect of improving fuel consumption. Japanese Laid-Open Patent Publication No. 6-313183 discloses an engine oil having a fuel efficiency improvement effect and high-temperature oxidation stability by combining MoDTP or MoDTC and an amine antioxidant, but both effects are insufficient. there were.
[0005]
[Problems to be solved by the invention]
The present invention has been made from the above viewpoint, and has an object to provide a lubricating oil composition for an internal combustion engine having a long oxidation life under high temperature conditions and having excellent fuel efficiency. is there.
[0006]
[Means for Solving the Problems]
As a result of intensive studies, the present inventors have found that the object of the present invention can be effectively achieved by combining specific additives with highly refined base oils, thereby completing the present invention. It is a thing. That is, the gist of the present invention is as follows.
(1) A mineral oil or synthetic oil having a kinematic viscosity at 100 ° C. of ² to 12 mm ² / s and a% CA of 2 or less by ring analysis (ndm method) is used as a base oil. Based on the total amount of the composition, (a) 0.02-0.15% by weight of zinc dithiophosphate as phosphorus (P), (b) basicity selected from the group consisting of succinimide, carboxylic acid amide and Mannich base An oil-soluble sulfur-containing molybdenum complex obtained by further reacting sulfur or thioacetamide with a molybdenum complex obtained by reacting a nitrogen compound and molybdenum trioxide with 20 to 100 ppm by weight of molybdenum (Mo), and ( c) dithiocarbamate molybdenum molybdenum (Mo) amount as 0.01 to 0.15 wt% blended lubricating oil composition for an internal combustion engine comprising.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below. First, in the present invention, mineral oil or synthetic oil is used as the base oil, and it is important that they have a kinematic viscosity at 100 ° C. of ² to 12 mm ² / s. Preferably it is 3-8 mm < ² > / s. If the kinematic viscosity is less than 2 mm ² / s, the evaporation loss is large, which is not preferable. On the other hand, if it exceeds 12 mm ² / s, the power loss due to viscous resistance becomes large and the fuel efficiency improvement effect cannot be obtained, which is not preferable. Moreover,% CA by ring analysis (ndm method) needs to be 2 or less . If it exceeds 2 , the oxidation stability at high temperature deteriorates.
As mineral oil, for example, a distillate obtained by subjecting paraffin-based crude oil, intermediate-based crude oil, or naphthenic-based crude oil to atmospheric distillation, or distilling atmospheric residue oil under reduced pressure, or using this as a conventional method Accordingly, refined oils obtained by refining, such as solvent refined oil, hydrogenated refined oil, dewaxed oil, and clay-treated oil, can be mentioned, among which the above viscosity range and% CA range Should be selected.
[0009]
On the other hand, as synthetic oil, for example, poly α-olefin, α-olefin copolymer, polybutene, polyisobutylene, alkylbenzene, polyol ester, dibasic acid ester, polyoxyalkylene glycol, polyoxyalkylene glycol ester, polyoxyalkylene glycol ether, Examples include trimellitic acid ester, hindered ester, and silicone oil.
Among these, poly α-olefin (PAO) is preferable.
These base oils can be used alone or in combination of two or more kinds, and mineral oil and synthetic oil may be used in combination.
[0010]
Next, the components (a) to (c) blended in the base oil will be described.
(A ) Component Zinc dithiophosphate (hereinafter referred to as ZnDTP) is represented by the following general formula (I).
[0011]
[Chemical 1]

[0012]
In the general formula (I), R ^{1 to} R ⁴ each represents a linear or branched alkyl group having 2 to 20 carbon atoms, preferably 3 to 10 carbon atoms, which may be the same or different.
Specifically, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, various pentyl groups, various hexyl groups, various heptyl groups, various octyl groups, Examples include various nonyl groups, various decyl groups, various undecyl groups, various dodecyls, various tridecyl groups, various tetradecyl groups, various pentadecyl groups, various hexadecyl groups, various heptadecyl groups, various octadecyl groups, various nonadecyl groups, and various eicosyl groups. it can. In addition, when introducing R ^{1 to} R ⁴ , a mixture of α-olefins may be used as a raw material. In this case, the component (a) is a mixture of ZnDTP having alkyl groups having different structures.
[0013]
(A) component, one kind or in combination of two or more can be used, the amount of that is the total amount of the composition, is 0.02 to 0.15 wt% of phosphorus (P) content. If it is less than 0.02% by weight, the friction reducing effect and the oxidation stability improving effect at high temperatures may not be sufficiently exhibited. If it exceeds 0.15% by weight, the improvement corresponding to the amount may not be recognized. Good Mashiku is in the range of 0.05 to 0.10 wt%.
[0014]
( B) component The sulfur-containing molybdenum complex described in JP- B- 3-22438. That is, oil solubility obtained by further reacting sulfur or thioacetamide with a molybdenum complex obtained by reacting molybdenum trioxide with a basic nitrogen compound selected from the group consisting of succinimide, carboxylic acid amide and Mannich base. This is a sulfur-containing molybdenum complex.
[0015]
The gist of JP-B-3-22438 is summarized as follows.
(1) As a succinimide, a reaction product of polyisobutenyl succinic anhydride having 70 to 128 carbon atoms and a polyamine such as tetraethylenepentamine or triethylenetetramine is preferably used.
(2) As a carboxylic acid amide, a fatty acid having 13 to 21 carbon atoms or a mixture of this fatty acid and a polyisobutenyl carboxylic acid having a polyisobutenyl group having 72 to 128 carbon atoms, triethylenetetramine, tetraethylenepentamine A reaction product with a polyamine such as is preferably used.
(3) As a Mannich base, a reaction product of phenol or an alkyl-substituted phenol having 9 to 200 carbon atoms, formaldehyde or paraformaldehyde, an alkylamine such as methylamine, or a polyamine such as diethylenetriamine or tetraethylenepentamine is preferable. Used for.
[0016]
(4) For the reaction between the basic nitrogen compound and molybdenum trioxide, water or ethylene glycol is used as a catalyst, and a lubricating oil or hydrocarbon solvent is preferably used as a diluent.
(5) The reaction between the basic nitrogen compound and molybdenum trioxide is carried out at a pressure around atmospheric pressure between the melting point of the mixture and the reflux temperature.
(6) The reaction product of a basic nitrogen compound and molybdenum trioxide usually contains 0.01 to 2 molybdenum atoms per basic nitrogen atom.
(7) The sulfur-containing molybdenum complex as the final product contains 0.1 to 4 sulfur atoms per molybdenum atom.
[0017]
(B) component, one kind or in combination of two or more can be used, the amount of that is the total amount of the composition, from 20 to 100 ppm by weight as molybdenum (Mo) amount. If it is less than 20 ppm by weight, the oxidation stability improving effect at high temperatures may not be sufficiently exhibited. If the amount exceeds 100 ppm by weight, the improvement corresponding to the amount may not be recognized. Good Mashiku is in the range of 40 to 80 weight ppm.
[0018]
( C) Component Molybdenum dithiocarbamate (hereinafter referred to as MoDTC) is represented by the following general formula (II).
[0019]
[Chemical 2]

[0020]
In general formula (II), R < ⁵ > -R < ⁸ > is a C5-C16 hydrocarbon group, and may be same or different altogether. X is S (sulfur atom) or O (oxygen atom). Examples of the hydrocarbon group represented by R ⁵ to R ^8, for example, an alkyl group having 5 to 16 carbon atoms, an alkenyl group having 5 to 16 carbon atoms, a cycloalkyl group having 5 to 16 carbon atoms, carbon atoms 5-16 And an arylalkyl group having 5 to 16 carbon atoms. Specific examples of the hydrocarbon having 5 to 16 carbon atoms include various pentyl groups, various hexyl groups, various heptyl groups, various octyl groups, various nonyl groups, various decyl groups, various undecyl groups, various dodecyl groups, various tridecyl groups, Various tetradecyl groups, various pentadecyl groups, various hexadecyl groups, various octenyl groups, various nonenyl groups, various decenyl groups, various undecenyl groups, various dodecenyl groups, various tridecenyl groups, various tetradecenyl groups, various pentadecenyl groups, cyclohexyl groups, dimethylcyclohexyl groups , Ethylcyclohexyl group, methylcyclohexylmethyl group, cyclohexylethyl group, propylcyclohexyl group, butylcyclohexyl group, heptylcyclohexyl group, phenyl group, tolyl group, dimethylphenyl group, butylphenyl group, nonylphenol Group, can be exemplified a methyl benzyl group, phenylethyl group, a naphthyl group, dimethyl naphthyl group and the like.
[0025]
(C) component, one kind or in combination of two or more can be used, the amount of that is the total amount of the composition, is 0.01 to 0.15 wt% as molybdenum (Mo) amount. If it is less than 0.01% by weight, the friction reducing effect and the oxidation stability improving effect at high temperatures may not be sufficiently exhibited. When it exceeds 0.15% by weight, the improvement of the effect commensurate with the amount is not recognized. Good Mashiku is in the range of 0.03 to 0.10 wt%.
[0026]
Furthermore, the lubricating oil composition of the present invention usually contains various additives conventionally used in lubricating oils, such as alkaline earth, within the range where the object of the present invention is not impaired in order to improve the physical properties of the lubricating oil. Metal detergents such as sulfonates, phenates, salicylates, etc., ashless dispersants such as succinimides and succinates, antioxidants such as phenols, amines and sulfurs, extreme pressures such as disulfides , Friction modifiers such as polyhydric alcohol partial esters, amines and amides, viscosity index improvers such as polymethacrylates and olefin copolymers, pour points of chlorinated paraffin-naphthalene condensates, polymethacrylates, polyacrylates, polyalkylstyrenes, etc. Depressants, metal deactivators such as benzotriazole and thiadiazole, alkenyl succinic acid and its partial esters, Anti-rusting agent such as realkylene ether and polyalkylene alkyl phenyl ether, antifoaming agent such as silicone oil, etc., based on the total amount of the composition, 3 to 10% by weight of all additives other than components (a) to (c) % Can be blended.
[0027]
【Example】
EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
Examples 1-6, Comparative Examples 1-4 and Reference Examples 1-3
The following additives were blended with the following base oils in the proportions shown in Tables 1 and 2 to obtain lubricating oil compositions of Examples , Comparative Examples , and Reference Examples . The lubricating oil composition was evaluated for high-temperature oxidation stability and friction coefficient by the methods described below, and the results are shown in Table 1 (Examples and Reference Examples ) and Table 2 (Comparative Examples).
(1) Base oil PAO (1-decene dimer hydride: kinematic viscosity at 100 ° C. 6.0 mm ² / s,% CA = 0, Example 1)
Mineral oil 1 (paraffinic mineral oil: kinematic viscosity at 100 ° C. 4.2 mm ² / s,% CA = 0, Examples 2 to 6 , Comparative Examples 2 to 4, Reference Examples 2 and 3 )
Mineral oil 2 (paraffinic mineral oil: kinematic viscosity at 100 ° C. 4.3 mm ² / s,% CA = 5.0, Reference Example 1 )
Mineral oil 3 (paraffinic mineral oil: kinematic viscosity at 100 ° C. 4.1 mm ² / s,% CA = 7.6, Comparative Example 1)
[0028]
(2) Additive (a) Component · ZnDTP (Zn content: 9.0 wt%, P content: 7.8 wt%, S content: 15.0 wt%, alkyl group is secondary and has 3 and 6 carbon atoms) And Examples 1 to 6 , Comparative Examples 1 to 3 , Reference Examples 1 to 3 ) which are primary and have 8 carbon atoms.
(B) Component / sulfur-containing Mo complex (prepared according to Example 1 of JP-B-3-22438, Mo content 6.3% by weight, S content 2.2% by weight, Examples 1-6 , comparison Examples 1 , 3 , 4 and Reference Examples 1-3 )
Component (c) · MoDTC (Mo content 4.5 wt%, S content of 5.7 wt%, carbon number of 8 to 13 alkyl groups, Examples 1 6 and Comparative Examples 1, 2, 4, Reference Example 1)
MoDTP ( Molybdenum dithiophosphate: Mo content 9.0% by weight, P content 3.3% by weight, S content 9.9% by weight, alkyl group carbon number 8, Reference Example 2 )
Mo amine salt (amine salt of molybdic acid: Mo content 4.5% by weight, Reference Example 3 )
[0029]
(3) Evaluation method (i) Friction coefficient (μ)
The block on ring tester (LFW-1) has a rotation speed of 1,400 rpm, a load of 20 lbs, an oil temperature of 80 ° C., a time of 15 minutes, and the amount of oil in which half of the ring is immersed in the sample oil. A load was applied to the block using a Falex S-10 test ring for the test block and test ring, and the resistance generated when the ring was rotated was detected with a strain gauge, and the friction coefficient was calculated.
(Ii) High-temperature oxidation stability Based on ASTM D-4742 (TFOUT), oxidation induction time (minutes) was measured under the following evaluation conditions.
(Evaluation conditions)
Test temperature: 160 ° C., oxygen pressure: 620 kPa, sample oil: 1.5 g,
Catalyst: SRM1817c, amount of water: 2% by weight of sample oil, amount of fuel catalyst: 4% by weight of sample oil, amount of metal catalyst: 4% by weight of sample oil
[0030]
[Table 1]

[0031]
[Table 2]

[0032]
[Table 3]

[0033]
[Table 4]

[0034]
【The invention's effect】
The lubricating oil composition for an internal combustion engine of the present invention has a long oxidation life under high temperature conditions and excellent fuel efficiency, and is particularly practical as an engine oil.

Claims (1)

A mineral oil or synthetic oil having a kinematic viscosity at 100 ° C. of ² to 12 mm ² / s and a% CA of 2 or less by ring analysis (ndm method) is used as the base oil. And (b) a basic nitrogen compound selected from the group consisting of succinimide, carboxylic acid amide and Mannich base, with (a) zinc dithiophosphate as the amount of phosphorus (P), 0.02 to 0.15% by weight An oil-soluble sulfur-containing molybdenum complex obtained by further reacting sulfur or thioacetamide with a molybdenum complex obtained by reacting with molybdenum trioxide in an amount of 20 to 100 ppm by weight as molybdenum (Mo), and (c) dithiocarbamine acid molybdenum molybdenum (Mo) amount as 0.01 to 0.15 wt% blended lubricating oil composition for an internal combustion engine comprising.