Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Organic -co- compound
Reexamination Certificate
2002-06-05
2003-09-02
Howard, Jacqueline V. (Department: 1764)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Organic -co- compound
Reexamination Certificate
active
06613724
ABSTRACT:
This invention relates to gas-fuelled engine lubricating oil compositions. Gas-fuelled engines can, for example, be found in mobile and stationary power sources.
Gas-fuelled engines, sometimes referred to as gas-fired engines or merely gas engines, are known and may be used in the oil and gas industry, for example, to drive pumping stations of natural gas pipelines, blowers and generators in purification plants and on gas tankers; and to compress natural gas at well heads and along pipe lines. Gas-fuelled engines also find application in motor vehicles, such as in passenger motor cars and in heavy-duty trucks, where the fuel is in the form of liquid petroleum gas or compressed natural gas. They are also used in electric power generation plants, particularly when they are also equipped with heat recovery systems.
The design of the gas-fuelled engines may be two- or four-stroke, spark-ignited or compression-ignited, though four-stroke compression-ignited designs constitute a large percentage. Natural gas constitutes a typical fuel.
The engines generally run continuously near full load conditions, shutting down only for maintenance, such as for oil changes. This condition of running continuously places severe demands on the lubricating oil composition, for example, the oil oxidation and nitration processes often limit the life of the lubricating oil composition. Therefore, it is desirable for gas-fuelled lubricating oil compositions to have long life through good resistance to oil oxidation and nitration.
U.S. Pat. No. 6,140,282 discloses a lubricating oil composition for gas engines comprising a major amount of oil and a minor amount of a mixture of a 64 TBN neutral calcium salicylate and a calcium sulfonate and/or phenate detergent. The examples either explicitly include an anti-oxidant or they include an additive system that includes an anti-oxidant.
JP-B-2970991 discloses oil compositions for gas engines, comprising base oil, an alkaline earth metal salicylate having base number of 175 to 300 mgKOH/g, a dispersant, a zinc dithiophosphate and an anti-oxidant selected from: a mixture of phenolic- and aminic-type compounds, di-t-butyl p-cresol, diphenylamine and a polymeric hindered phenol compound.
The aim of the present invention is to provide improved gas-fuelled lubricating oil compositions. In particular, the aim of the present invention is to provide gas-fuelled lubricating oil compositions exhibiting good performance towards oil oxidation and nitration processes, so that the interval between an oil change can be extended, and improved anti-corrosion properties.
Applicant has found a defined gas-fuelled lubricating oil composition that provides good resistance to oil oxidation and nitration processes and improved anti-corrosion properties.
Accordingly, a first aspect of the present invention is a gas-fuelled engine lubricating oil composition having a sulfated ash content according to ASTM D-874 of 0.01 to 1.3%, which comprises or is made by admixing:
(i) a major amount of oil of lubricating viscosity;
(ii) a minor amount of a detergent composition comprising at least one calcium salicylate having a TBN in the range from 70 to 245 according to ASTM D-2896, preferably in the range from 95 to 195;
(iii) 0 to 0.2 mass % of nitrogen, based on the mass of the oil composition, of a dispersant; and
(iv) a minor amount of one or more co-additives;
with the proviso that the oil composition is substantially free from an anti-oxidant additive.
In a second aspect, the present invention provides use of the gas-fuelled engine lubricating oil composition defined in the first aspect to reduce viscosity increase and minimize acidity increase.
In a third aspect, the present invention provides use of the gas-fuelled engine lubricating oil composition defined in the first aspect to provide resistance to oxidation and nitration processes.
In a fourth aspect, the present invention provides use of the gas-fuelled engine lubricating oil composition to improve corrosion resistance.
In a fifth aspect, the present invention provides a method of lubricating a gas-fuelled engine, which method comprises supplying a lubricating oil composition of the first aspect to the engine.
In a sixth aspect, the present invention provides a concentrate for a gas-fuelled engine lubricating oil composition, the concentrate being substantially free from an anti-oxidant additive and comprising:
(ii) more than 40 mass %, preferably a major amount, of a detergent composition comprising at least one calcium salicylate having a TBN in the range from 70 to 245 according to ASTM D-2896, preferably in the range from 95 to 195;
(iii) 0 to 0.5 mass % of nitrogen, based on the mass of the oil composition, of a dispersant; and
(iv) a minor amount of one or more co-additives.
The lubricating oil compositions according to the first aspect have been found to be effective in lubricating gas-fuelled engines in heavy-duty trucks, pumping stations of natural gas pipelines, and stationary power sources.
The acidity of the lubricating oil composition is determined by ASTM D-664.
“Major amount” means in excess of 50 mass % of the composition, preferably in excess of 60 mass % of the composition, more preferably in excess of 70 mass % of the composition, and most preferably in excess of 80 mass % of the composition.
“Minor amount” means less than 50 mass % of the composition, preferably less than 40 mass %, more preferably less than 30 mass % and most preferably less than 20 mass %, both in respect of the stated additive and in respect of the total mass % of all the additives present in composition, reckoned as active ingredient of the additive or additives.
“Comprises or comprising” or a cognate word is taken to specify the presence of the stated features, steps, integers or components, but does not preclude the presence or addition of one or more other features, steps, integer components or groups thereof.
“Consists essentially or consisting essentially” or a cognate word is taken to specify the presence of the stated features, steps, integers or components, but does not preclude the presence or addition of one or more other features, steps, integer components or groups thereof provided their inclusion does not substantially affect the present invention.
“Consists or consisting” or a cognate word is taken to specify the presence of the stated features, steps, integers or components and no other features, steps, integers or components.
“Substantially free from an anti-oxidant additive” means 0.25 or less, preferably 0.1 or less, more preferably 0.05 or less, mass %, based on active ingredient, of anti-oxidant, based on the mass of the oil composition.
Unless otherwise started, all proportions are expressed as mass % active ingredient, i.e. as if solvent or diluent or other inert material was absent.
The features of the present invention will now be discussed in more detail.
Lubricating Oil Composition
Gas-fuelled engine lubricating oil compositions of the present invention preferably have from 0.01 to 1, more preferably from 0.01 to 0.5, even more preferably from 0.1 to 0.5, % of sulfated ash, as measured according to ASTM D874.
Preferably, the gas-fuelled engine lubricating oil compositions of the present invention have a total base number (TBN), as measured according to ASTM D-2896, in the range from 2 to 20, preferably 2 to 12. Gas-fuelled engine lubricating oil compositions, which have a TBN in the range from 2 to 10 are especially preferred, advantageously the TBN is in the range from 2 to 7, more advantageously from 4 to 7.
In a preferred embodiment of the present invention, the gas-fuelled engine lubricating oil composition has from 0.0 to 0.1 mass % of phosphorus, based on the mass of the oil composition. The oil composition especially has less than 0.8, more preferably less than 0.05, preferably in the range from 0.02 to 0.03, mass % of phosphorus. The amount of phosphorus is measured according to method to ASTM D-5185.
Applicant has found that the gas-fuelled engine lubricating oil composition of the present invention is effecti
Chambard Laurent
Strickland Keith
Howard Jacqueline V.
Infineum International Ltd.
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