Search

EP-4317370-B1 - LUBRICANT COMPOSITION

EP4317370B1EP 4317370 B1EP4317370 B1EP 4317370B1EP-4317370-B1

Inventors

  • SUNAHARA, KENJI
  • FUJITA, Shoichiro
  • KUBOTA, MASAYA

Dates

Publication Date
20260506
Application Date
20220317

Claims (15)

  1. A lubricating oil composition comprising a base oil (A), a molybdenum-based friction modifier (B), a metal-based detergent (C), and an ash-free dispersant (D), wherein the molybdenum-based friction modifier (B) contains two or more selected from a group consisting of a binuclear molybdenum dithiocarbamate (B1), a trinuclear molybdenum dithiocarbamate (B2), and a molybdenum-amine complex (B3), the metal-based detergent (C) contains a sulfur atom, the ash-free dispersant (D) contains a nitrogen atom, an acid value derived from the binuclear molybdenum dithiocarbamate (B1) and the trinuclear molybdenum dithiocarbamate (B2) as measured according to JIS K2501:2003 is less than 0.04 mgKOH/g, a content ratio of a sulfur content (C S ) derived from the metal-based detergent (C) to a nitrogen content (D N ) derived from the ash-free dispersant (D), [(C S )/(D N )] is 0.30 to 0.85 in terms of mass ratio, and a phosphorus content based on a total amount of the lubricating oil composition is more than 0.04% by mass and less than 0.10% by mass.
  2. The lubricating oil composition according to claim 1, wherein the sulfur content based on the total amount of the lubricating oil composition is 0.35% by mass or less.
  3. The lubricating oil composition according to claim 1 or 2, wherein the phosphorus content based on the total amount of the lubricating oil composition is 0.06% by mass to 0.08% by mass.
  4. The lubricating oil composition according to any one of claims 1 to 3, wherein the molybdenum content based on the total amount of the lubricating oil composition is 0.05% by mass to 0.12% by mass.
  5. The lubricating oil composition according to any one of claims 1 to 4, wherein the metal-based detergent (C) contains one or more selected from a group consisting of a calcium-based detergent (C1) and a magnesium-based detergent (C2).
  6. The lubricating oil composition according to claim 5, wherein the metal-based detergent (C) contains the calcium-based detergent (C1), and the calcium content based on the total amount of the lubricating oil composition is 0.10% by mass to 0.20% by mass.
  7. The lubricating oil composition according to claim 5, wherein the metal-based detergent (C) contains the magnesium-based detergent (C2), and the magnesium content based on the total amount of the lubricating oil composition is 0.03% by mass to 0.07% by mass.
  8. The lubricating oil composition according to claim 5, wherein the metal-based detergent (C) contains the calcium-based detergent (C1) and the magnesium-based detergent (C2), the calcium content based on the total amount of the lubricating oil composition is 0.10% by mass to 0.20% by mass, and the magnesium content based on the total amount of the lubricating oil composition is 0.03% by mass to 0.07% by mass.
  9. The lubricating oil composition according to any one of claims 1 to 8, wherein the binuclear molybdenum dithiocarbamate (B1) is a compound represented by the following general formula (b1-3). [In the general formula (b1-3), R 1 , R 2 , R 3 , and R 4 each independently represent a group of short-chain substituent groups (α) which are aliphatic hydrocarbon groups having 4 to 12 carbon atoms or a group of long-chain substituent groups (β) which are aliphatic hydrocarbon groups having 13 to 22 carbon atoms, provided that a molar ratio between the group of short-chain substituent groups (α) and the group of long-chain substituent groups (β) in a total molecule of the compound (B1), [(α)/(β)] is 0.10 to 2.0. Further, in the general formula (b1-3), X1, X2, X3 and X4 each independently represent an oxygen atom or a sulfur atom.]
  10. The lubricating oil composition according to any one of claims 1 to 9, further comprising a metal deactivator (E).
  11. The lubricating oil composition according to any one of claims 1 to 10, wherein an ash-free friction modifier content based on the total amount of the lubricating oil composition is less than 0.1% by mass.
  12. Use of the lubricating oil composition according to any one of claims 1 to 11 in an internal combustion engine.
  13. An internal combustion engine comprising the lubricating oil composition according to any one of claims 1 to 11.
  14. A method of lubricating an internal combustion engine using the lubricating oil composition according to any one of claims 1 to 11.
  15. A method of producing a lubricating oil composition, comprising a step of mixing a base oil (A), a molybdenum-based friction modifier (B), a metal-based detergent (C), and an ash-free dispersant (D), wherein the molybdenum-based friction modifier (B) contains two or more selected from a group consisting of a binuclear molybdenum dithiocarbamate (B1), a trinuclear molybdenum dithiocarbamate (B2), and a molybdenum-amine complex (B3), the metal-based detergent (C) contains a sulfur atom, the ash-free dispersant (D) contains a nitrogen atom, an acid value derived from the binuclear molybdenum dithiocarbamate (B1) and the trinuclear molybdenum dithiocarbamate (B2) as measured according to JIS K2501:2003 is less than 0.04 mgKOH/g, a content ratio of a sulfur content (C S ) derived from the metal-based detergent (C) to a nitrogen content (D N ) derived from the ash-free dispersant (D), [(C S )/(D N )] is adjusted to be 0.30 to 0.85 in terms of mass ratio, and a phosphorus content based on a total amount of the lubricating oil composition is adjusted to be more than 0.04% by mass and less than 0.10% by mass.

Description

Technical Field The present invention relates to a lubricating oil composition. Background Art In recent years, lubricating oil compositions used in internal combustion engines such as engines are required to have further improved fuel saving properties. For this reason, the viscosity of lubricating oil compositions has been reduced, and research on molybdenum-based friction modifiers has been progressing from the viewpoint of exhibiting a higher friction reducing effect. As a molybdenum-based friction modifier, for example, binuclear molybdenum dithiocarbamate and trinuclear molybdenum dithiocarbamate are known (see, for example, PTL 1). Citation List Patent Literature PTL 1: WO 2017/002969 A Summary of Invention Technical Problem In recent years, there has been a demand for further improvement in a friction reducing effect. Therefore, it is conceivable to further improve the friction reducing effect by using a combination of plural types of molybdenum-based friction modifiers. However, as a result of intensive studies by the present inventors, it has been found that the high-temperature detergency and oxidation stability of a lubricating oil composition deteriorates when the inventors attempt to further improve the friction-reducing capability by combining plural types of molybdenum-based friction modifiers. In addition, it has been found that the copper corrosion resistance of the lubricating oil composition also deteriorates. The lubricating oil composition with poor copper corrosion resistance may accelerate deterioration due to copper elution into oils due to corrosion of copper-based members used in internal combustion engines such as engines. The present invention has been made in view of such problems, and an object of the present invention is to provide a lubricating oil composition which, even while exhibiting an excellent friction reducing effect by combining plural types of molybdenum-based friction modifiers, has excellent high-temperature detergency, oxidation stability and copper corrosion resistance. In the present description, "copper corrosion resistance" means that even when a copper-based member is corroded, copper elution into oil is unlikely to occur. Solution to Problem In order to solve the above problems, the present inventors have made intensive studies and have found the following configuration. That is, the present invention relates to the following aspects. A lubricating oil composition containing a base oil (A), a molybdenum-based friction modifier (B), a metal-based detergent (C), and an ash-free dispersant (D), wherein the molybdenum-based friction modifier (B) contains two or more selected from the group consisting of a binuclear molybdenum dithiocarbamate (B1), a trinuclear molybdenum dithiocarbamate (B2), and a molybdenum-amine complex (B3),the metal-based detergent (C) contains a sulfur atom,the ash-free dispersant (D) contains a nitrogen atom,an acid value derived from the binuclear molybdenum dithiocarbamate (B1) and the trinuclear molybdenum dithiocarbamate (B2) as measured according to JIS K2501:2003 is less than 0.04 mgKOH/g,a content ratio of a sulfur content (CS) derived from the metal-based detergent (C) to a nitrogen content (DN) derived from the ash-free dispersant (D), [(CS)/(DN)] is 0.30 to 0.85 in terms of mass ratio, anda phosphorus content based on a total amount of the lubricating oil composition is more than 0.04% by mass and less than 0.10% by mass. Use of the lubricating oil composition according to the above in an internal combustion engine. An internal combustion engine containing the lubricating oil composition according to the above. A method of lubricating an internal combustion engine using the lubricating oil composition according to the above. A method of producing a lubricating oil composition, including a step of mixing a base oil (A), a molybdenum-based friction modifier (B), a metal-based detergent (C), and an ash-free dispersant (D), wherein the molybdenum-based friction modifier (B) contains two or more selected from the group consisting of a binuclear molybdenum dithiocarbamate (B1), a trinuclear molybdenum dithiocarbamate (B2), and a molybdenum-amine complex (B3),the metal-based detergent (C) contains a sulfur atom,the ash-free dispersant (D) contains a nitrogen atom,an acid value derived from the binuclear molybdenum dithiocarbamate (B 1) and the trinuclear molybdenum dithiocarbamate (B2) as measured according to JIS K2501:2003 is less than 0.04 mgKOH/g,a content ratio of a sulfur content (CS) derived from the metal-based detergent (C) to a nitrogen content (DN) derived from the ash-free dispersant (D), [(CS)/(DN)] is adjusted to be 0.30 to 0.85 in terms of mass ratio, anda phosphorus content based on a total amount of the lubricating oil composition is adjusted to be more than 0.04% by mass and less than 0.10% by mass. Advantageous Effects of Invention According to the present invention, it is possible to provide a lubricating oil com