Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Nitrogen and heavy metal – or nitrogen and aluminum – in the...
Patent
1997-03-14
1998-09-15
Gibson, Sharon
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Nitrogen and heavy metal, or nitrogen and aluminum, in the...
508364, 508379, 508444, 508438, C10M13518, C10M13710, C10M14500
Patent
active
058078134
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of PCT/JP96/019881,filed Jul. 17, 1996.
TECHNICAL FIELD
The present invention relates to a lubricating oil composition. Particularly, the present invention relates to a lubricating oil composition which enables exhibiting the low friction effect of organic molybdenum compounds for a longer time. More particularly, the present invention relates to a lubricating oil composition which maintains the low friction property to achieve sustained low fuel consumption during the use, enables using the organic molybdenum compound added as the friction modifier in a smaller amount than the amount required in conventional lubricating oil compositions, and can particularly advantageously be used as a lubricating oil for internal combustion engines.
BACKGROUND ART
Heretofore, lubricating oils are used in internal combustion engines, driving apparatus, such as automatic transmissions, shock absorbers, power steering, and the like, and gears in order to achieve smooth movements of these apparatus. Particularly, lubricating oils for internal combustion engines (generally called engine oils) play the roll of lubricating various types of sliding part, such as combinations of piston rings and cylinder liners, combinations of crank shafts and bearings of connecting rods, and moving valve mechanisms including cams and valve lifters, and also play the roll of cooling the inside of engines, cleaning and dispersing combustion products, and preventing rust and corrosion.
As described above, various properties are required for a lubricating oil. Particularly in recent years, decrease in the friction coefficient of engine oil is required for the purpose of improving fuel economy. Heretofore in internal combustion engines, because friction parts to which lubricating oils are related cause a large energy loss, friction modifiers, such as molybdenum dithiophosphate (MoDTP) and molybdenum dithiocarbamate (MoDTC), are frequently used in order to decrease the friction loss and the fuel consumption. However, it has been pointed out that oils containing MoDTP or MoDTC lose the expected effect significantly at an early time of use.
The decrease in the expected effect of the organic molybdenum compound at an early time of use has heretofore been considered to be caused by consumption of the molybdenum compound. Therefore, the added amount of the molybdenum compound is generally increased to compensate the amount lost by the decomposition. However, it has been found in recent years that the decrease in the effect is caused by the formation of degradation products of fuels (degradation acids) although the consumption of the organomolybdenum compound is small.
On the other hand, many studies have been conducted on the mechanism of the function of the molybdenum compound. For example, studies have been conducted on the effect of the type of the compound, the effect of the atmosphere, and the interaction of the compound with zinc dithiophosphate (ZnDTP) which is one of additives to engine oils. However, one study alone can be found in relation to the sustenance of the effect, i.e., it was reported in "Preprints for Scientific Meeting of Automotive Engineers, Japan", Volume 952, Page 207 that the effect of MoDTP to improve fuel consumption could be maintained by increasing the used amount of MoDTP and by simultaneously using an additive containing sulfur.
Under the above circumstance, the present invention has the object of providing a lubricating oil composition which maintains the low friction property to achieve sustained low fuel consumption during the use, enables using the organic molybdenum compound added as the friction modifier in a smaller amount than the amount required in conventional lubricating oil compositions, and can particularly advantageously be used as a lubricating oil for internal combustion engines.
DISCLOSURE OF THE INVENTION
As the result of extensive studies conducted by the present inventors to develop the lubricating oil composition having the above advantageous properties, it was discove
REFERENCES:
patent: 4812246 (1989-03-01), Yabe
patent: 4832867 (1989-05-01), Seiki et al.
patent: 4877541 (1989-10-01), Wisotsky et al.
patent: 5076945 (1991-12-01), Habeeb
Gibson Sharon
Idemitsu Kosan Co. Ltd.
Toomer Cephia D.
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