Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Organic compound containing silicon
Reexamination Certificate
2002-07-18
2003-07-01
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 silicon
C508S409000, C508S505000, C508S506000, C508S586000, C508S591000
Reexamination Certificate
active
06586374
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to engine lubricating oils and, more particularly, to a composition for, and method of using, a custom formulated, engineered, full synthetic engine oil having a significantly longer service life, improved lubricity, lower operating cost, and fewer health, safety and environmental risks than conventional engine lubricants.
2. Description of Related Art
The use of engine lubricants in both gasoline and diesel engines is well known. Historically, virtually all engine lubricants consisted primarily of refined hydrocarbon oils into which additive packages were blended to achieve improved properties and service life as necessary to achieve certification by organizations such as the Society of Automotive Engineers (SAE). In recent years, the use of synthetic lubricating oils for gasoline engines has become more widespread. Generally speaking, the cost of synthetic oils is greater than for conventional mineral oil lubricants but synthetic oils offer improved lubricity, lower oil consumption, better engine protection and longer service life for both the lubricating oil and the engines in which it is used. With increased emphasis on the use of synthetic oils and resultant competition among suppliers, several different types of synthetic lubricants have emerged, some of which perform only marginally better than lubricants have emerged, some of which perform only marginally better than conventional oils and may not provide long term savings that justify the higher initial cost.
Full synthetic oils consist primarily of high quality synthetic polyalphaolefin (“PAO”) base stocks and are typically priced much higher than conventional engine lube oils. Synthetic oils are now recommended for use in some automotive engines, particularly in high performance engines and those in luxury automobiles. Generally speaking, synthetic oils are viewed as having improved lubricity and longer service life when compared to conventional motor oils. However, because PAO base stocks are significantly more expensive than refined mineral oils, many consumers have resisted switching to synthetic oils because of cost.
As a result of price sensitivity on the part of consumers, many producers of so-called “synthetic” oils now manufacture and market blends in which more highly refined mineral oils are used in place of most, and in some cases all, of the PAO. The percentage of synthetic base stock in blended synthetic oils (sometimes referred to as “partial” synthetics) can vary, for example, from as little as about three weight percent in the lower grades up to about 30 weight percent in higher grade products, sometimes referred to as “engineered blends.” Such blends lack many of the improved properties previously associated with full synthetic oils containing a high percentage of PAO. Also, these lower grade “synthetic” lubricants may produce byproducts that foul or otherwise inhibit engine performance during use.
Beyond automotive use, the need for effective engine lubricants for diesel engines is also well known. Large diesel engines are widely used in various oilfield, industrial and transportation applications. Such engines are normally expected to remain in continuous or substantially continuous service for long periods, utilize heavier and more contaminated fuels than gasoline engines, and are frequently operated under heavy loads. In such use environments, lubricating oils that demonstrate great lubricity, long service life, lower oil consumption, better engine protection and overall cost effectiveness are often critical to the success of the related venture. Lubricity is necessary for achieving mechanical efficiency, reduced engine wear and longer intervals between major overhauls. Extended service life is desirable to reduce the out-of-service time, labor and material costs associated with oil changes. Also, by reducing the total volume of lubricating oil required to service an engine over an extended period, other cost efficiencies such as lower freight, handling and storage costs are achieved. Furthermore, longer service life, fewer oil changes and reduced transportation and handling all contribute to less worker exposure to health and safety risks, and less chance of accidental leakage or spills that can adversely affect the environment.
Lubricating oils consisting primarily of petroleum refined mineral oil and various additive packages are normally used in large diesel engines. Some synthetic oils have previously been disclosed and certified for diesel engines but their use has not become widespread. This is believed to be primarily attributable to the relatively large lubricant capacities associated with diesel engines that, when coupled with the higher selling price of synthetic lubricants, has previously been viewed as more than offsetting any related cost advantages in service life or performance. Many operators have failed, however, to fully appreciate all the costs associated with using inferior lubricants.
Diesel engines such as those used to power generators on offshore drilling platforms, for example, often have oil pans or sumps containing more than a hundred gallons of lubricating oil. Such engines are sometimes operated for 5,000 to 7,000 hours in a single year. When using a conventional lubricating oil consisting primarily of mineral oil, oil changes may be required as often as every 1,000 hours, and even more often where the diesel fuel contains more than about 0.5 weight percent sulfur or where impurities and additives in the oil contribute to the formation of sludge or acidic byproducts.
The acidity of a lubricating oil generally increases with extended use over time. As oils become more acidic, they can corrode engine parts, cause loss of power and increased repair costs. Lubricating oils typically have a total base number (“TBN”) in the range of about 8 to 10 when placed in service and are changed whenever the TBN drops to about 3 or 4. Where operators fail to maintain rigorous maintenance schedules and run engines with dirty or ineffective lubricant, significant engine wear can occur within relatively short periods, necessitating expensive overhauls and associated downtime.
An engineered, full synthetic lubricant is therefore needed that can be safely and effectively utilized in either gasoline or diesel-fueled engines and that will demonstrate superior performance and service life benefits which far surpass and justify any related increase in original purchase costs.
SUMMARY OF THE INVENTION
The lubricating oil disclosed herein is an engineered full PAO synthetic oil specially tailored for use as a high performance lubricant in gasoline and diesel engines. Engineered full synthetic oils are those made to the highest standards using the best PAO base stock available and are the most expensive and highest performing of the synthetic lubricating oils. These “full PAO” lubricants are designed rather than refined. As used herein, the term “full PAO” refers to lubricants containing only PAO as the principal base stock component, although viscosity improvers and minor amounts of other additives are used to further enhance the lubricant properties. It should be understood, however, that minor amounts of refined mineral oil may be present in the lubricants of the invention as diluents for some of the other additive components. The total amount of petroleum based oil used as a diluent in the compositions of the invention will preferably not exceed about 17 percent of the total lubricant by volume.
The synthetic engine lubricants of the invention are preferably formulated so as to meet or exceed the requirements for SAE 5W40 lubricants for gasoline or diesel engines. Such lubricants must have a product viscosity between about 12.9 and 16.7 centistokes (cs) over the requisite temperature range. The lubricants of the invention will desirably have a viscosity ranging between about 14.5 and 16.5 cs, preferably between about 15 and 16 cs, and most preferably, about 15.5 cs. Because the preferred PAO for use in the composit
Howard Jacqueline V.
Locke Liddell & Sapp LLP
Primrose Oil Company
Ross Monty L.
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