Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Organic -co- compound
Reexamination Certificate
2002-03-29
2004-06-15
McAvoy, Ellen M (Department: 1764)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Organic -co- compound
C508S501000, C508S555000, C508S559000, C508S561000, C508S562000, C508S579000
Reexamination Certificate
active
06750185
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a lubricant oil composition for internal combustion engines and a friction reducing method for internal combustion engines and, more specifically, relates to a lubricant oil composition useful for reduction of friction loss and improvement in fuel economy in automotive internal combustion engines, particularly a lubricant oil composition for internal combustion engines suitable for lubrication of diesel engines equipped with an exhaust gas recirculation system (hereinafter often referred to as “EGR”).
BACKGROUND OF THE INVENTION
Lubricant oils are used for sliding parts of internal combustion engines, for example, piston rings, cylinder liners, crankshafts, bearings for connecting rods, valve system mechanisms including cams and valve lifters, and the like. However, because of their large energy loss by friction, in general, various techniques have been developed to reduce the friction loss and improve the fuel economy. As a friction reducing agent to be added to lubricant oils to reduce the friction coefficients of lubricant oils, for example, attention is paid to organic molybdenum compounds, and a combination of organic molybdenum compound with metallic detergent (e.g., Kokoku publication No. 6-62933), a combination of organic molybdenum compound with sulfur compound (e.g., Kokoku publication No. 5-83599) and the like have been proposed. As a friction reducing agent different from the organic molybdenum compounds, further, a combination of glycerol partial ester of fatty acid with organic copper compound (e.g., Kokoku publication No. 3-77837), a combination of pentaerythritol with succinimide or zinc dithiophosphate (Kokoku publication No. 55-80494), and the like have also been proposed.
However, the production of soot resulting from incomplete combustion of diesel fuel cannot be avoided in a diesel engine, unlike a gasoline engine, and the engine oil is contaminated with the produced soot. Accordingly, conventional friction reducing agents such as organic molybdenum compound, amine compounds, amide compounds and the like involve a difficulty in that a sufficient effect cannot be exhibited due to the influence of the soot in oil. To improve the fuel economy of diesel engines, only the mixing with alkali metal borate hydrate (e.g., Kokoku publication No. 1-48319) has been proposed.
From the viewpoint of prevention of global warming, measures of reducing CO
2
emission are increasingly required, and it is requested in Japan, for example, to improve the fuel consumption of diesel passenger cars by 14.9% on the average (compared with 10-15 mode fuel consumption/'95) from the 2005.
In the installation of the EGR system as the measures of reducing NOx emissions from diesel engines, the soot in oil is still increased to aggravate the wear of valve systems and pistons/cylinders by the soot, and the fuel economy effect by the friction reducing agent cannot be fully exhibited. There is an increasing expectation for development of fuel economy techniques for diesel engine oils, and the development of lubricant oil compositions for internal combustion engines capable of reducing the wear in the presence of soot is desired.
SUMMARY OF THE INVENTION
The subject of this invention is to provide a lubricant oil composition capable of reducing friction of internal combustion engines even in the presence of the soot resulting from incomplete combustion of fuel, particularly, a lubricant oil composition suitable for diesel engines equipped with EGR.
In the view of the problems of the prior arts as described above, the present inventors have found, that a lubricant oil composition obtained by mixing a nonionic surfactant with a specified alkylene oxide added thereto with a lubricant base oil is effective even under a lubricating conditions with soot in the oil, and an enhanced friction reducing effect can be exhibited by controlling its hydrophile lipophile balance (“HLB”) value and molecular weight, reaching the completion of this invention on the basis of such a knowledge.
This invention relates first to a lubricant oil composition comprising a lubricant base oil incorporated with 0.01 wt % or more, based on the total weight of the lubricant oil composition, of a nonionic surfactant with alkylene oxide added thereto consisting of at least one compound with an HLB value of 15 or more and a weight average molecular weight (hereinafter referred to as “molecular weight” for short) of 900 or more.
This invention relates secondly to a friction reducing method for internal combustion engines comprising, in an internal combustion engine in which a lubricant oil for sliding parts is contaminated with soot present in combustion exhaust gas, using a lubricant oil composition for internal combustion engines comprising a lubricant base oil incorporated with 0.01 wt % or more, based on the total weight of the lubricant oil composition, of a nonionic surfactant with alkylene oxide added thereto consisting of at least one compound with an HLB value of 15 or more and a molecular weight of 900 or more in the presence of the soot in oil.
As described above, this invention provides a lubricant oil composition for internal combustion engine comprising a lubricant base oil incorporated with an alkylene oxide-added nonionic surfactant consisting of a compound with an HLB value of 15 or more and a molecular weight of 900 or more, and a friction reducing method for internal combustion engine using this lubricant oil composition for internal combustion engines, and this invention involves the following (1) to (7) as preferable embodiments.
(1) A lubricant oil composition for internal combustion engines according to the above wherein the alkylene oxide-added nonionic surfactant is formed of a compound comprising a lipophilic group component having a bond group introduced thereto and a hydrophilic group component and containing an alkylene oxide group.
(2) A lubricant oil composition for internal combustion engines according to the above wherein the alkylene oxide-added nonionic surfactant contains at least one compound selected from the group consisting of compounds represented by the following general formulae (I) to (VI).
Chemical Formula 1
R
1
—O&Parenopenst;R
1
O&Parenclosest;
n
H (I)
Chemical Formula 2
R
2
—COO&Parenopenst;R
2
O&Parenclosest;
n
R
22
(II)
Chemical Formula 3
[R
3
—COO&Brketclosest;
P
Y&Brketopenst;O&Parenopenst;R
3
O&Parenclosest;
n
H]
q
(III)
Chemical Formula 4
Chemical Formula 5
Chemical Formula 6
In the above general formulae (I) to (VI),
1. R
1
, R
2
, R
3
, R
4
, R
5
and R
6
, which may be the same or different, each represents an alkyl group having 8-30 carbon atoms; an alkenyl group having 8-30 carbon atoms; an aromatic hydrocarbon group having 6-30 carbon atoms; or an aromatic hydrocarbon group substituted by at least one alkyl group or alkenyl group having 8-24 carbon atoms.
2. R
22
represents hydrogen atom or —OCR
2
.
3. R
1
-R
10
, which may be the same or different, each represents an alkylene group.
4. m and n, which may be the same or different, each represents the polymerization number of alkylene oxides.
5. Y represents the frame part of a polyhydric alcohol component.
6. p and q each represents an integer of 1 or more, and the total thereof is not more than the number of hydroxyl groups of the polyhydric alcohol.
7. R
55
represents an alkylene group.
(3) A lubricant oil composition for internal combustion engines according to the above wherein R
1
, R
2
, R
3
, R
4
, R
5
and R
6
in the above general formulae (I) to (VI), which may be the same or different, each represents an alkyl group or alkenyl group having 17-24 carbon atoms.
(4) A lubricant oil composition for internal combustion engines according to the above wherein R
1
, R
2
, R
3
, R
4
, R
5
and R
6
, which are the same or different, each represents a phenyl group substituted by at least one alkyl group or alkenyl group having 8-18 carbon atoms.
(5) A lubricant oil composition for internal combustion engines accordin
Nemoto Shuzo
Ogano Satoshi
Ryu Sonmin
Foss Norby L.
McAvoy Ellen M
Scuorzo Linda M.
TonenGeneral Sekiyu K.K.
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