Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Phosphosulfurized or phosphooxidized organic compound of...
Reexamination Certificate
2001-09-20
2003-02-18
McAvoy, Ellen M. (Department: 1764)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Phosphosulfurized or phosphooxidized organic compound of...
C508S354000, C508S436000, C508S502000, C508S569000, C508S572000
Reexamination Certificate
active
06521571
ABSTRACT:
This invention relates to a lubricant suitable for use in a trunk piston diesel (compression-ignited) engine. Trunk piston diesel engines are used in marine, power generation and rail traction applications.
Trunk piston diesel engines are known for use in water-borne vessels, i.e. for so-called marine applications, including auxiliary power generation, and also for land-based applications such as power-generation. They may be characterised as medium-speed engines, e.g. in contrast to slow-speed cross-head engines requiring separate cylinder lubrication using a marine diesel cylinder lubricant.
Problems in the lubrication of trunk piston diesel engines may arise from the high temperatures to which the lubricant is subjected. For example, lubricating oil compositions, or lubricants, for trunk piston diesel engines (commonly referred to as trunk piston engine oils or TPEOs) may give non-optimal performance in their ability to resist formation of piston undercrown deposits.
The present invention provides a solution to the problem by using specific additives to enable the oil to resist the adverse effects of high temperature.
Thus, in a first aspect, the invention is a lubricant for use in a four-stroke trunk piston diesel engine, the lubricant comprising, or made by admixing:
(A) a base stock of lubricating viscosity, in a major amount;
(B) at least one overbased metal detergent, preferably having an ash content (as determined in accordance with ASTM D874) of at least 0.85% sulfated ash, in a minor amount; and
(C) at least one auxiliary ashless or metal-free additive component, in a minor amount, and that is different from (B), selected from:
(C1) an oil-soluble sulfurized alkylphenol, a phosphorosulfurized or sulfurized hydrocarbon, and a sulfide of an oil, a fat or a polyolefin, and/or
(C2) an amine phosphate.
A second aspect of the invention is a method of lubricating a four-stroke trunk piston diesel engine for use in marine, power generation or rail traction, the engine having a power output of 200 or greater, such as 400 or greater, preferably 550 or greater, more preferably in the. range of 600 to 100,000, kW, which method comprises supplying to the engine the lubricant defined above.
A third aspect of the invention is a method of raising the temperature of the onset of the hydrodynamic film in operation of a four-stroke trunk piston diesel engine for use in marine, power generation or rail traction, the engine having a power output of 200 or greater, such as 400 or greater, preferably 550 or greater, more preferably in the range of 600 to 100,000, kW, the method including the step of lubricating the engine with the lubricant defined above.
A fourth aspect of the invention is the use of additives (B) and (C) as defined above in a lubricant to suspend asphaltene components in the lubricant when used in a four-stroke trunk piston diesel engine in marine, power generation or rail traction, the engine having a power output of 200 or greater, such as 400 or greater, preferably 550 or greater, more preferably in the range of 600 to 100,000, kW.
The fourth aspect of the invention relates to a problem in use of TPEOs commonly referred to as “black paint” whereby they may become contaminated with asphaltene components from the fuel used, when a residual fuel, leading to cleanliness problems in service. Thus, the lubricant in the present invention may further comprise a fuel oil with a residual fuel content, in a minor amount.
Phenate-based detergents may benefit the high temperature performance of TPEOs; however their use limits the amount of salicylate-based detergent, necessary for meeting the above-mentioned “black paint” and other problems, that may be used. The present invention, by providing high temperature performance benefits other than arising from phenate use, enables more salicylate to be used as the detergent and thereby enables both high temperature performance and “black paint” control requirements to be met. In the invention therefore, the lubricant may be substantially free of phenate-based detergents and/or comprise salicylate as the sole type of detergent.
In this specification, the following words and expressions shall have the meanings ascribed below:
“major amount”—in excess of 50 mass % of the lubricant;
“minor amount”—less that 50 mass % of the lubricant, both in respect of the stated additive and in respect of the total mass % of all the additives present in the lubricant, reckoned as active ingredient of the additive or additives;
“active ingredient (a.i.)” refers to additive material that is not diluent.
“comprises or comprising, or cognate words”—specifies the presence of stated features, steps, integers or components, but does not preclude the presence or addition of one or more other features, steps, integers, components, or groups thereof;
“TBN”—Total Base Numbers as measured by ASTM D2896;
“oil-soluble or oil-dispersible”—do not necessarily indicate solubility, dissolvability, miscibility or capability of suppression in oil in all proportions. They do mean, however, solubility or stable dispersibility sufficient to exert the intended effect in the environment in which the oil is employed. Moreover, additional incorporation of other additives may permit incorporation of higher levels of a particular additive, if desired; it will be understood that the various components of the lubricant, essential as well as optimal and customary, 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 features of the invention will now be discussed in more detail as follows:
Trunk Piston Diesel Engine
The trunk piston diesel engine may, for example, be a four-stroke trunk piston diesel engine suitable for use in marine, power generation or rail traction applications. The engines preferably have a power output of 200 or greater, such as 400 or greater, preferably 550 or greater, more preferably in the range of 600 to 100,000, kW. Further, the engines may, for example, have an engine speed in the range of from 200 to 2,000, preferably 400 to 1,000, rpm, and a brake horse-power (BHP) per cylinder of 50 to 10,000, preferably 100 to 7,000.
Lubricant
The lubricant may, for example, have a TBN in the range of from 25 to 100, such as from 25 or 30 to 60, to 55, preferably, 40, for example in the range of from 60 to 100. Preferably, the viscosity index of the lubricant is at least 90, more preferably at least 95, and at most 140 such as 120, preferably 110. A preferred viscosity index range is from 95 to 115.
The lubricant may, for example, have a kinematic viscosity at 100° C. (as measured by ASTM D445) of at least 9, preferably at least 13, more preferably in the range from 14 to 24, for example from 14 to 22, mm
2
s
−1
.
(A) Base Stock of Lubricating Viscosity
The base stock is an oil of lubricating viscosity (sometimes referred to as base oil) and may be any oil suitable for the lubrication of a trunk piston engine. The lubricating oil may suitably be an animal, vegetable or a mineral oil. Suitably the lubricating oil is a petroleum derived lubricating oil, such as a naphthenic base, paraffinic base or mixed base oil. Alternatively, the lubricating oil may be a synthetic lubricating oil. Suitable synthetic lubricating oils include synthetic ester lubricating oils, which oils include diesters such as di-octyl adipate, di-octyl sebacate and tri-decyl adipate, or polymeric hydrocarbon lubricating oils, for example liquid polyisobutene and poly-alpha olefins. Commonly, a mineral oil is employed. The lubricating oil may generally comprise greater that 60, typically greater than 70%, by mass of the lubricant and typically have a kinematic viscosity at 100° C. of from 2 to 40, for example from 3 to 15, mm
2
s
−1
, and a viscosity index from 80 to 100, for example from 90 to 95.
Another class of lubricating oil is hydrocracked oils, where the refining process further breaks down the middle and heavy distillate fractions in the presence of hydrogen at hig
Chambard Laurent
Dunn Adrian
Garner Terence
Infineum International Ltd.
McAvoy Ellen M.
LandOfFree
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