Patent Application
20080227674
Exemplary embodiments of the present invention relate the use of lubricating oil in an internal combustion engine. More particularly, exemplary embodiments of the present invention relate to regeneration of dispersant incorporated into lubricating oil.
During engine operation, contacting parts rub against each other at high speeds, often for prolonged periods of time. The resulting friction absorbs otherwise useful power produced by the motor and converts the energy into useless heat. In addition, the friction wears away the contacting surfaces of these parts, and this wear can have the effect of increasing fuel consumption and degrading and lowering the efficiency of the motor.
Lubricating oil, or lubricant, is used by various kinds of internal combustion engines in automobiles and other vehicles, boats, lawn mowers, trains, airplanes, etc., to create a film between surfaces of parts moving against each other to minimize contact therebetween and decrease friction, wear, and production of excessive heat. Lubricant further cools the engine by carrying heat away from the moving engine parts.
Because engine soot, which can form as a result of incomplete fuel combustion, is a common by-product of internal combustion engines, lubricant also plays a cleaning role in the engine. Soot particles are spherical in shape and 98 percent carbon by weight. They typically form in a very small size (around 0.03 microns), but they often agglomerate to form larger particles. These microscopic soot particles accumulate in the oil during operation and threaten to grind against the moving engine parts, and thereby cause erosion and wear. Because these undesirable particles inevitably build up in lubricating oil, the oil is circulated through an oil filter to remove the harmful particles.
Lubricating oils also often include additives such as detergents and dispersants that help keep the engine clean by minimizing sludge build up, corrosion inhibitors, and alkaline additives that neutralize acidic oxidation products of the oil. Detergents and dispersants keep oil-insoluble combustion products in suspension and prevent the agglomeration of resinous and asphalt-like oxidation products. This inhibits the formation of deposits on metal surfaces, oil thickening and sludge deposition, and also prevents corrosive wear by neutralising acidic products of combustion.
While the oil filter removes many of the particles, the oil filter eventually becomes filled up. As this occurs, the oil and especially the additives undergo thermal and mechanical degradation. In high soot conditions, dispersants can become quickly depleted, leading to a loss of oil dispersancy and permitting soot particles to agglomerate and form larger particles that build up on engine surfaces. This soot eventually impedes oil flow and also can form on oil filters, blocking oil flow and allowing dirty oil into the engine. For these reasons, the oil and the oil filter need to be periodically replaced to improve fuel efficiency, lower temperature, and prevent wear.
Dispersants are increasingly required to allow engine lubricants to operate for longer periods and to carry the dirt that builds up in use. Nevertheless, when the soot concentration in the oil exceeds the amount of dispersant, the dispersant becomes deactivated. Further, over periods of use, dispersants tend to chemically degrade and lose their dispersing properties. Dispersants, which tend to be expensive, are no longer useful in the treatment process when deactivated or degraded. Accordingly, there is a need for a process for regenerating used dispersant additives incorporated into lubricating oil that removes the suspended soot from the dispersant, thereby prolonging the useful life of the lubricating oil by allowing the dispersant to continue to capture soot in the engine and prevent agglomeration.
Exemplary embodiments of the present invention pertain to a method of regenerating used dispersant incorporated into lubricating oil. The method comprises the steps of supplying used lubricating oil having dispersant molecules suspending particulate matter into a regenerating chamber; releasing the particulate matter by creating a stress on the bond between the dispersant molecules and the suspended particulate matter; permitting the released particulate matter to agglomerate; removing the agglomerated particulate matter from the lubricating oil; and discharging the lubricating oil back to the engine. An alternative method comprises the steps of supplying used lubricating oil having non-metallic polymer dispersant molecules suspending particulate matter into a capturing chamber, the dipersant molecules having polar ends and non-polar tails; interacting the used lubricating oil with an oil-insoluble capturing composition having a binding affinity for the particulate matter that is greater than that of the polar ends of the dispersant molecules to displace the suspended particulate matter and bind the particulate matter to the capturing composition within the capturing chamber; and discharging the lubricating oil back to the engine.
For a more complete understanding of the present invention, the reader is referred to the following detailed description section, which should be read in conjunction with the accompanying drawings. Throughout the following detailed description and in the drawings, like numbers refer to like parts.
While the specification concludes with claims defining the features of the invention that are regarded as novel, it is believed that the invention will be better understood from a consideration of the description of exemplary embodiments in conjunction with the drawings. It is of course to be understood that the embodiments described herein are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed in relation to the exemplary embodiments described herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriate form. Furthermore, the terms and phrases used herein are not intended to be limiting but rather to provide an understandable description of the invention.
As shown in the exemplary embodiment illustrated in
Referring now to
At step 130, the suspended particulate matter is released from the dispersant molecules by creating a stress on the bond between the dispersant molecules and the particulate matter. This can be done, for instance, by increasing the temperature within the regeneration chamber if the type of dispersant used has a high enthalpy. Auxiliary regeneration additives, such as elements from the transition metals (for example, cerium, iron, copper, strontium, and platinum), can also be included in the lubricating oil to depress the energy required to break the particulate-dispersant bond. The heat can be supplied by, for instance, power from the vehicle's onboard electrical system that warms the regeneration chamber to the appropriate temperature, thus permitting well-controlled regeneration of the dispersant.
Once the bond between the particulate matter and the dispersant is broken, at step 140, the released particulate matter can be permitted to agglomerate. As shown in the exemplary embodiment illustrated in
Once the particulate matter has agglomerated, the agglomerated particulate matter is removed from the lubricating oil at step 150. Because the particle size of the particulate matter will be larger at this step, conventional filtration or centrifugation can be used to separate and remove the particulate matter. At this point, the present exemplary process has regenerated the dispersant in the lubricating oil by removing or substantially reducing the particulate matter, thereby substantially restoring the dispersing ability of the dispersant to its original level. At step 160, the regenerated lubricating oil can be discharged back to the engine using, for instance, the oil pump or a light phase outlet of the regeneration chamber, where the free dispersant will continue to capture particulate matter and prevent agglomeration.
Referring now to
At step 230, the used lubricating oil is caused to interact with an oil-insoluble capturing composition. The capturing composition has a binding affinity for the particulate matter that is greater than that of the polar ends of the non-metallic dispersant polymer molecules. The capturing composition can be, for instance, disposed on a surface of fibrous media or included as part of a solvent phase within the capturing chamber.
In exemplary, non-limiting embodiments in which the capturing composition employed at step 230 is disposed on a surface of fibrous media, the media can be incorporated in a filter system. The fibrous media intercepts the particulate the matter through inertial forces and retains the particulates through chemical binding. The filter system can involve stand-still regeneration or exchangeable filters that are regenerated through combustion of the captured particulate matter, and then disposed of and replaced at the end of the life-cycle of the system.
In exemplary, non-limiting embodiments in which the capturing composition employed at step 230 is included as part of a solvent phase within the capturing chamber, the dispersant is not soluble in the displacing solvent, and the displacing solvent is not be soluble in oil. For a sufficiently high-degree of impaction to facilitate the chemical reaction of the step, the immiscible oil and solvent phases should be mixed until equilibrium is reached. Because the dispersant is insoluble in the solvent, the particulate matter will be displaced from the dispersant in the lubricating oil and extracted into the solvent phase. Once this ion transfer is complete, the solvent, which now carries the particulate matter, and the oil, which contains the dispersant that is now free of particulate matter, are permitted to separate. For better dispersant recovery, the lubricating oil, in exemplary embodiments, can be sequentially mixed with two equal volumes or several smaller volumes of solvent rather than with all the solvent in one large volume.
In other exemplary, non-limiting embodiments in which the capturing composition employed at step 230 is included as part of a solvent phase within the capturing chamber, a phase transfer catalyst for capturing the particulate matter can be utilized. In these exemplary embodiments, the capturing catalyst can be immobilized on a fiber surface through which the lubricating oil is filtered. During filtration, the particulate matter is displaced from the dispersant in the lubricating oil and reacts to bond with the catalyst. As a result of the reaction, the particulate matter becomes soluble in the solvent phase, which enables the particulate matter to be separated from the oil and move into the solvent phase, thereby freeing the dispersant molecules, which remain in the oil.
The interaction that takes place step 230 causes, at step 240, a chemical reaction within the capturing chamber in which the suspended particulate matter is displaced from the dispersant molecules and binds to the capturing composition (for example, the particulate matter can be bound to a capture surface or within a solvent phase). The operation of displacement and binding can be seen in the exemplary reaction illustrated in
At this point in exemplary process 200, the dispersant in the lubricating oil has been regenerated by having the particulate matter that had been suspended therein removed or substantially reduced, thereby substantially restoring the dispersing ability of the dispersant to its original level. The lubricating oil can then, at step 250, be discharged back to the engine using, for instance, the oil pump or a light phase outlet of the regeneration chamber, where the free dispersant can capture particulate matter and prevent agglomeration.
While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof Therefore, it is intended that the invention not be limited to the particular embodiments disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the present application.
This application claims the benefit of U.S. patent application Ser. No. 60/895,133, filed Mar. 15, 2007, the contents of which are incorporated herein by reference thereto.
| Number | Date | Country | |
|---|---|---|---|
| 60895133 | Mar 2007 | US |
