Engine oil with improved fuel economy properties (law372).

• US 5,658,862 A
• Filed: 01/19/1996
• Issued: 08/19/1997
• Est. Priority Date: 12/20/1994
• Status: Expired due to Fees

• Current Assignee: Exxon Research and Engineering Company (Exxon Mobil Corporation)
• Original Assignee: Exxon Research and Engineering Company (Exxon Mobil Corporation)
• Inventors: Vrahopoulou, Elisavet P.
• Primary Examiner(s): MEDLEY, MARGARET B
• Application Number:
  US08/589,176
• Time in Patent Office: 578 Days
• Field of Search: 252/49.6, 252/32.7, 252/39, 252/33.6, 252/51.5 A, 508/192, 508/365, 508/379, 508/536, 508/591
• US Class Current: 508/192
• CPC Class Codes: C10M 129/54 containing hydroxy groups
• CPC Class Codes: C10M 133/56 Amides; Imides
• CPC Class Codes: C10M 135/18 thiocarbamic type, e.g. containing the groups
• CPC Class Codes: C10M 137/10 Thio derivatives
• CPC Class Codes: C10M 141/08 at least one of them being an organic sulfur-, selenium- or tellurium-containing compound
• CPC Class Codes: C10M 141/10 at least one of them being an organic phosphorus-containing compound
• CPC Class Codes: C10M 143/02 Polyethene
• CPC Class Codes: C10M 161/00 Lubricating compositions characterised by the additive being a mixture of a macromolecular compound and a non-macromolecular compound, each of these compounds being essential
• CPC Class Codes: C10M 2205/00 Organic macromolecular hydrocarbon compounds or fractions, whether or not modified by oxidation as ingredients in lubricant compositions
• CPC Class Codes: C10M 2205/022 Ethene
• CPC Class Codes: C10M 2207/144 containing hydroxy groups
• CPC Class Codes: C10M 2207/146 having carboxyl groups bound to carbon atoms of six-membeered aromatic rings having a hydrocarbon substituent of thirty or more carbon atoms
• CPC Class Codes: C10M 2207/262 derived from hydroxy substituted aromatic acids, e.g. salicylates
• CPC Class Codes: C10M 2215/04 having amino groups bound to acyclic or cycloaliphatic carbon atoms
• CPC Class Codes: C10M 2215/042 containing hydroxy groups; Alkoxylated derivatives thereof
• CPC Class Codes: C10M 2215/086 Imides
• CPC Class Codes: C10M 2215/26 Amines
• CPC Class Codes: C10M 2215/28 Amides; Imides
• CPC Class Codes: C10M 2217/046 Polyamines, i.e. macromoleculars obtained by condensation of more than eleven amine monomers
• CPC Class Codes: C10M 2217/06 Macromolecular compounds obtained by functionalisation op polymers with a nitrogen containing compound
• CPC Class Codes: C10M 2219/066 : Thiocarbamic type compounds
• CPC Class Codes: C10M 2219/068 : Thiocarbamate metal salts
• CPC Class Codes: C10M 2223/045 : Metal containing thio derivatives
• CPC Class Codes: C10M 2227/061 : Esters derived from boron
• CPC Class Codes: C10N 2010/12 : Groups 6 or 16
• CPC Class Codes: C10N 2020/01 : Physico-chemical properties
• CPC Class Codes: C10N 2040/25 : Internal-combustion engines
• CPC Class Codes: C10N 2040/251 : Alcohol-fuelled engines
• CPC Class Codes: C10N 2040/255 : Gasoline engines
• CPC Class Codes: C10N 2040/28 : Rotary engines

Abstract

A lubricating oil composition having improved fuel economy and fuel economy retention property which comprises a lubricating oil basestock, a boron containing alkenyl succinimide, molybdenum, di-thiocarbamate and/or molybdenum dithiophosphate, calcium and magnesium salicylate, and ethylene copolymer.

Claims

1. An engine oil for an internal combustion engine having improved fuel economy and fuel economy retention properties comprises:

(a) an oil base stock,

(b) at least 2 wt %, based on engine oil, of a boron containing alkenyl succinimide with the proviso that the boron concentration in the engine oil is about 900 to 2000 ppmw, based on engine oil, wherein the ratio of (d) to component (e) is in the range of 8/1 to 1/8,

(c) from 50 to 2000 ppmw, based on engine oil, of molybdenum atoms present as molybdenum dithiophosphate or molybdenum dithiocarbamate,

(d) from 50 to 4000 ppmw, based on engine oil, of calcium atoms present as calcium salicylate,

(e) from 50 to 4000 ppmw, based on engine oil, of magnesium atoms present as magnesium salicylate, and

(f) from 0 to 15 wt %, based on engine oil, of a copolymer of ethylene and at least one other alpha-olefin monomer, wherein said copolymer has a molecular weight distribution characterized by at least one of a ratio of M_w /M_n of less than 2 and a ratio of M_z /M_w of less than 1.8, and wherein the copolymer comprises intramolecularly heterogeneous polymeric chains containing at least one crystallizable segment of methylene units and at least one low crystallinity ethylene-alpha-olefin copolymer segment, wherein the crystallizable segment comprises at least about 10 wt % of the copolymer chain and contains as average ethylene content of at least about 57 wt %, wherein the low crystallinity segment contains an average ethylene content of from about 20 to 53 wt %, and wherein at least two portions of an individual intramolecularly heterogeneous chain, each portion comprising at least 5 wt % of said chain, differ in composition from one another by at least 7 wt % ethylene.

2. The engine oil of claim 1 wherein the copolymer has an intermolecular compositional dispersity such that 95 wt % of copolymer chains have a composition 15 wt % or less different from the average ethylene composition.

3. The engine oil of claim 1 wherein the copolymer has a molecular weight distribution characterized by a M_w /M_n and a M_z /M_w ratio less than about 1.5.

4. The engine oil of claim 1 wherein the copolymer has a weight-average molecular weight of 20,000 to 1,000,000.

5. The copolymer of claim 4 wherein the weight-average molecular weight is from 50,000 to 500,000.

6. The engine oil of claim 1 wherein the polyalkenyl succinimide is a polyisobutenyl succinimide.

7. The engine oil of claim 1 wherein component (b) is molybdenum dithiocarbamate.

8. A method for improving the fuel economy and fuel retention performance of an internal combustion engine which comprises operating the engine with the engine oil of claim 1.

9. The engine oil claim 6 wherein component (b) is molybdenum dithiocarbamate.