Lubricating oil composition for internal combustion engines

• US 6,114,288 A
• Filed: 05/03/1999
• Issued: 09/05/2000
• Est. Priority Date: 05/01/1998
• Status: Expired due to Fees

• Current Assignee: Shell Oil Company (Shell Plc)
• Original Assignee: Shell Research Limited (Shell Plc)
• Inventors: Kubo, Koichi, Fujitsu, Takashi, Nagakari, Mitsuhiro
• Primary Examiner(s): Medley, Margaret
• Assistant Examiner(s): Toomer, Cephia D.
• Application Number:
  US09/304,020
• Time in Patent Office: 491 Days
• Field of Search: 508/371, 508/551, 508/376, 508/378
• US Class Current: 508/371
• CPC Class Codes: C10M 163/00 Lubricating compositions characterised by the additive being a mixture of a compound of unknown or incompletely defined constitution and a non-macromolecular compound, each of these compounds being essential
• CPC Class Codes: C10M 2207/262 derived from hydroxy substituted aromatic acids, e.g. salicylates
• CPC Class Codes: C10M 2215/08 Amides
• CPC Class Codes: C10M 2223/045 Metal containing thio derivatives
• CPC Class Codes: C10N 2010/04 Groups 2 or 12
• CPC Class Codes: C10N 2030/02 Pour-point; Viscosity index
• CPC Class Codes: C10N 2030/06 Oiliness; Film-strength; Anti-wear; Resistance to extreme pressure
• CPC Class Codes: C10N 2030/42 Phosphor free or low phosphor content compositions
• CPC Class Codes: C10N 2030/45 Ash-less or low ash content
• CPC Class Codes: C10N 2030/68 Shear stability
• CPC Class Codes: C10N 2040/25 Internal-combustion engines
• CPC Class Codes: C10N 2050/10 Semi-solids; greasy

Abstract

Lubricating oil composition for internal combustion engines having a high temperature shear viscosity of from 2.1 to less than 2.9 mPas wherein the lubricating base oil comprises 1) a zinc dialkyldithiophosphate, 2) a metallic detergent chosen from calcium alkylsalicylate and a mixture of calcium alkylsalicylate and magnesium alkylsalicylate and optionally 3) friction modifier.

Claims

1. A lubricating oil composition having a sulfated ash content and being free of molybdenum for internal combustion engines which has a high temperature high shear viscosity according to ASTM D 4683 in the range of from 2.1 to less than 2.9 mPas, which composition comprises lubricating base oil and

(1) zinc dialkyldithiophosphate having a primary and/or secondary alcohol mixed therewith in a residue so that the phosphorus content in the oil is from 0.04 to 0.12 mass %, wherein the relationship between the primary and secondary alcohol in the zinc dialkyldithiophosphate alcohol residue satisfies the following

expression in terms of the amount (mass %) of elemental phosphorus in the oil:

space="preserve" listing-type="equation">0.04≦

(Pri)+(Sec)≦

0.12

space="preserve" listing-type="equation">(Pri)=0 to 0.03

where, (Pri) is the mass % of primary alcohol residue and (Sec) is the mass % of secondary alcohol residue, and

(2) a metallic detergent selected from the group consisting of calcium alkylsalicylate and ii) a mixture of calcium alkylsalicylate and magnesium alkylsalicylate wherein the lubricating oil sulphated ash content is from 0.8 to 1.8 mass %, according to JIS K2272, and optionally,

(3) at most 2.0 mass % of friction modifier.

2. A lubricating oil composition according to claim 1, wherein the zinc dialkyldithiophosphate has an alkyl group of from 3 to 12 carbon atoms.

3. A lubricating oil composition according to claim 1, wherein the alkylsalicylate compound(s) content is from 1 to 8% mass of the lubricating oil composition.

4. A lubricating oil composition according to claim 1 wherein the amount of metallic magnesium does not exceed the amount of calcium.

5. A lubricating oil composition according to claim 1 wherein the friction modifier is fatty acid amide.

6. A lubricating oil composition according to claim 1 wherein the friction modifier is present in an amount of from 0.05 to 0.35 mass %, based on total composition.