Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Organic compound containing boron
Reexamination Certificate
2001-03-14
2002-07-23
Howard, Jacqueline V. (Department: 1764)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Organic compound containing boron
C508S364000, C508S365000, C508S372000, C508S380000, C508S398000, C508S586000
Reexamination Certificate
active
06423670
ABSTRACT:
The present invention relates to a crankcase lubricant which exhibits superior performance properties in heavy duty (HD) diesel (compression ignited) internal combustion engines whilst being a low phosphorus formulation. Such lubricants may be referred to variously as lubricating oils, lubricating oil compositions, and lubricating oil formulations.
The heavy duty trucking market has come to adopt the diesel engine as its preferred power source due to both its excellent longevity and its economy of operation. Specialized lubricants have been developed to meet the more stringent performance requirements of HD diesel engines compared with passenger car engines.
Several engine tests are required to demonstrate satisfactory HD performance, including the following:
Sequence IIIE (ASTM D553) test for antioxidancy as measured by viscosity increase.
Daimler Chrylser OM364LA diesel engine test for bore polish, piston cleanliness, cylinder wear, engine sludge and oil consumption.
Cummins M11 test to evaluate soot-related valve train wear, filter plugging and sludge.
Thus, there is a need in the art for lubricating oils that are capable of meeting the HD diesel requirements. Surprisingly, a low phosphorus lubricating oil which affords improved performance in the Sequence IIIE, OM364LA and Cummins M11 tests has now been discovered. Thus, the present invention is directed, in a first aspect, towards a heavy duty diesel engine lubricating oil composition comprising a major amount of an oil of lubricating viscosity to which has been added:
(a) a lubricating oil borated or non-borated ashless dispersant which has not more than 0.3, for example not more than 0.2, such as not more than 0.1, mass % boron, in a minor amount;
(b) an oil-soluble neutral calcium phenate detergent in a minor amount;
(c) an oil-soluble overbased calcium or magnesium sulfonate or mixture thereof present in a minor amount so that not more than 0.1, for example not more than 0.05, such as not more than 0.025, mass % magnesium is present in the composition;
(d) a metal dihydrocarbyldithiophosphate present in such an amount that the phosphorus content of the composition is from 0.025 to 0.10, such as 0.05 to 0.07 or to 0.08, mass %; and
(e) a antioxidant phenolic or aminic, preferably a hindered phenol, in a minor amount, the composition being free of any neutral metal sulfonate and any other neutral metal detergent, other than the phenate (b).
As used herein, all mass % numbers are on an active ingredient basis unless otherwise noted, and are based on elemental boron, magnesium or phosphorus in respect of (a), (c) and (d) above as appropriate.
The composition is preferably free of aminic, such as aromatic amine, antioxidants.
A major amount means in excess of 50 mass % of the composition and a minor amount means less than 50 mass % of the composition, both in respect of the stated additive, and in respect of the total mass % of all of the additives present in the composition.
It will be understood that the additives of the composition may react under the conditions of formulation, storage, or use and that the invention also provides the product obtainable or obtained as a result of any such reaction.
The word “comprises” or comprising”, or cognate words, when used in this specification, is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, or components.
In a second aspect, the invention is directed towards a concentrate for blending with an oil of lubricating viscosity to provide a heavy duty diesel engine lubricating oil composition, said concentrate comprising:
(a) a lubricating oil borated or non-borated ashless dispersant which has not more than 0.3, for example not more than 0.2, such as not more than 0. 1, mass % boron;
(b) an oil-soluble neutral calcium phenate detergent;
(c) an oil-soluble overbased calcium or magnesium sulfonate or mixture thereof present in such an amount so that not more than 0.3 mass % magnesium is present in the concentrate;
(d) a metal dihydrocarbyldithiophosphate present in such amount so that the phosphorus content of the concentrate is up to 0.7 mass %; and
(e) a phenolic or aminic, preferably a hindered phenol, antioxidant, the concentrate being free of any neutral metal sulfonate and any other neutral metal detergent, other than the phenate (b).
In a third aspect, the invention is directed towards a method of lubricating a heavy duty diesel engine which comprises supplying to the crankcase thereof a lubricating oil composition according to the first aspect of the invention.
In the fourth aspect, the invention is directed towards the use in a crankcase lubricating oil composition of a combination of additives (a) to (e) according to the first aspect of the invention to achieve adequate performance in one or more of the following tests for crankcase lubricating oils:
Sequence IIIE (ASTM D553) for antioxidancy;
Daimler Chrysler OM364LA for bore polish, piston cleanliness, cylinder wear, engine sludge, and oil consumption;
Cummins M11 for soot-related valve train wear, filter plugging and sludge.
In a fifth respect, the invention is directed towards a combination comprising
(i) moveable, contacting mechanical parts to be lubricated of a heavy duty diesel internal combustion engine; and
(ii) a lubricating oil composition according to the first aspect of the invention.
The features of the invention will now be discussed in further detail as follows.
Lubricating Oil
The oil of lubricating viscosity may be selected from any of the synthetic or natural oils used as crankcase lubricating oils for heavy duty diesel (compression-ignited) engines. The oil of lubricating viscosity conveniently has a viscosity of 2.5 to 12, preferably 2.5 to 9, mm
2
/s at 100° C. Mixtures of synthetic and natural base oils may be used if desired.
Dispersant (a)
The ashless dispersant comprises an oil-soluble polymeric hydrocarbon backbone having functional groups that are capable of associating with particles to be dispersed. Dispersants may be present in amounts of from 2 to 10, preferably 3 to 5, mass %. Typically, the dispersants comprise amine, alcohol, amide, or ester polar moieties attached to the polymer backbone often via a bridging group. The dispersant may be, for example, selected from oil-soluble salts, esters, amino-esters, amides, imides, and oxazolines of long chain hydrocarbon substituted mono and dicarboxylic acids or their anhydrides; thiocarboxylate derivatives of long chain hydrocarbons; long chain aliphatic hydrocarbons having a polyamine attached directly thereto; and Mannich condensation products formed by condensing a long chain substituted phenol with formaldehyde and polyalkylene polyamine, and Koch reaction products.
The oil-soluble polymeric hydrocarbon backbone is typically an olefin polymer, especially polymers comprising a major molar amount (i.e. greater than 50 mole %) of a C
2
to C
18
olefin (e.g., ethylene, propylene, butylene, isobutylene, pentene, octene-1, styrene), and typically a C
2
to C
5
olefin. The oil-soluble polymeric hydrocarbon backbone may be a homopolymer (e.g., polypropylene or polyisobutylene) or a copolymer of two or more of such olefins (e.g., copolymers of ethylene and an alpha-olefin such as propylene and butylene or copolymers of two different alpha-olefins).
One preferred class of olefin polymers is polybutenes and specifically polyisobutenes (PIP,) or poly-n-butenes, such as may be prepared by polymerization of a C
4
refinery stream. Another preferred class of olefin polymers is ethylene alpha-olefin (EAO) copolymers or alpha-olefin homo- and copolymers such as may be prepared using metallocene chemistry having in each case a high degree (e.g.>30%) of terminal vinylidene unsaturation.
The oil-soluble polymeric hydrocarbon backbone will usually have number average molecular weight ({overscore (M)}n) within the range of from 300 to 20,000. The {overscore (M)}n of the backbone is preferably within the range of 500 to 10,000, more pr
Locke Christopher J.
MacDonald Isabel P.
Howard Jacqueline V.
Infineum International Ltd.
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