Patent Application
20080060949
This application relates to an apparatus and method for removing soot from lubricating oils, and more particularly this application relates to soot removal through the use of electro-agglomeration.
In modern automobiles, many types of fluid filters are common. An oil filter is a fluid filter used to strain the oil in the engine thus removing abrasive particles. Most such filters use a mechanical or ‘screening’ type of filtration, with a replaceable cartridge having a porous filter element therein, through which oil is repeatedly cycled to remove impurities such as small particles or dirt and metal. “Dirty” oil enters an oil filter under pressure, passes through the filter media where it is “cleaned,” and then is redistributed throughout the engine. This can prevent premature wear by ensuring that impurities will not circulate through the engine and reach the close fitting engine parts. Filtering also increases the usable life of the oil.
It is common for the normal operation of an internal combustion engine particularly that of a diesel engine, to result in the formation of contaminants. These contaminants include, among others, soot, which is formed from incomplete combustion of the fossil fuel, and acids that result from combustion. Both of these contaminants are typically introduced into the lubricating oil during engine operation and tend to increase oil viscosity and generate unwanted engine deposits, leading to increased engine wear.
The conventional solution to these problems has been to place various additives into lubricating oils, during their initial formulation. In order to combat soot-related problems, many conventional lubricating oils include dispersants that resist agglomeration of soot therein. These work well for a short period, but may become depleted. Additionally and due to the solubility and chemical stability limits of these dispersants in the oil, the service lives of the lubricating oil and the oil filter are less than optimal.
In order to counteract the effects of acidic combustion products, many conventional motor oils include neutralizing additives known as over-based detergents. These are a source of TBN (total base number), which is a measure of the quantity of the over-based detergent in the oil, expressed in terms of the equivalent number of milligrams of potassium hydroxide that is required to neutralize all basic constituents present in 1 gram of sample. Higher TBN oils provide longer lasting acid neutralization. The depletion of TBN is an important limiting factor for many internal combustion engines, and in particular for heavy-duty applications with diesel engines.
In order to improve engine protection and to combat other problems, conventional lubricating oils often include one or more further additives, which may be corrosion inhibitors, antioxidants, friction modifiers, pour point depressants, detergents, viscosity index improvers, anti-wear agents, and/or extreme pressure additives. The inclusion of these further additives may be beneficial; however, with conventional methods, the amount and concentration of these additives are limited by the ability of lubricating oils to suspend these additives, as well as by the chemical stability of these additives in the oil.
In addition to trapping impurities and decontaminating oil, it is the role of the oil filter to ensure fast and efficient flow through its media. Oil is the life blood of an engine, and its constant flow is essential for proper lubrication of engine components and the prevention of friction, heat and wear. Engine components rely on the oil circulation system to deliver a steady and adequate supply of motor oil.
Accordingly, it is desirable to provide a method and apparatus for removing the oil soot.
Disclosed herein is an apparatus and method for removing soot from engine oil. In one exemplary embodiment, a method for removing soot from an engine oil is provided, the method comprising: disposing an oil containing soot between a pair of electrodes; applying a DC or AC current to the electrodes for a period of time, wherein portions of the soot agglomerate on a positive electrode of the pair of electrodes and the positive electrode is removed thereby removing the soot from the oil.
In another exemplary embodiment an apparatus and method for removing soot from engine oil is disclosed. In one exemplary embodiment, a method for removing soot from an engine oil is provided, the method comprising: disposing an oil containing soot between a pair of electrodes; applying a DC or AC current to the electrodes for a period of time, wherein portions of the soot agglomerate on a positive electrode of the pair of electrodes and other portions of the soot not collected on the positive electrode is preagglomerated resulting in a larger average particle diameter; and applying a centrifugal force to the oil to remove the soot.
In one exemplary embodiment, a method for removing soot from engine oil is provided, the method comprising: disposing an oil containing soot particles between a pair of electrodes; applying a direct current to the electrodes for a period of time to generate an electric field, wherein the electric field causes a portion of the soot particles to agglomerate on a positive electrode of the pair of electrodes; and removing the positive electrode and the portion of soot particles agglomerated on the positive electrode to reduce the amount of soot particles in the oil.
In another exemplary embodiment a method for removing soot from engine oil is provided, the method comprising: disposing an oil containing soot particles between a pair of electrodes; applying a DC or AC current to the pair of electrodes for a period of time to generate an electric field, wherein the electric field causes the soot particles to agglomerate resulting in a larger average particle diameter of the soot particles; and removing the soot particles by a filtering process.
In another exemplary embodiment a filter for removing soot particles from an engine oil having soot particles disposed therein is provided, the filter comprising: a housing having an inlet and an outlet defining a flow path through a chamber defined by the housing; a mechanical filter element disposed inside the filter housing in the flow path; a pair of electrodes disposed in the flow path, the pair of electrodes being electrically coupled to a direct current, wherein an electric filed is generated by the pair of electrodes and one of the pair of electrodes is a positive electrode, wherein the electric field causes a portion of the soot particles to agglomerate on the positive electrode.
In another exemplary embodiment a filter for removing soot particles from an engine oil having soot particles disposed therein is provided, the filter comprising: a housing having an inlet and an outlet defining a flow path through a chamber defined by the housing; a pair of electrodes disposed in the flow path, the pair of electrodes being electrically coupled to a AC current, wherein an electric filed is generated by the pair of electrodes and wherein the electric field causes a portion of the soot particles to agglomerate resulting in a larger average particle diameter of the soot particles and some of the soot particles are removed by a filtering process.
The above-described and other features and advantages of the present application will be appreciated and understood by those skilled in the art from the following detailed description, drawings, and appended claims.
FIGS. 16 is a partial cross-sectional view of the filter illustrated in
A major negative to the use of centrifugal methods for soot removal is the relatively low efficiency as currently practiced. In accordance with an exemplary embodiment of the present invention methods and apparatus for soot removal from an oil are provided. Non-limiting embodiments are directed to an oil filtration device (e.g., filter) that is configured to apply an electric field in accordance with an exemplary embodiment of the present invention. Thereafter, the agglomerated soot is removed via removal of a soot covered electrode, application of a centrifugal force, and/or subsequent filtration by a filtration media. In accordance with an exemplary embodiment, any one of the three methods may be employed alone or in combination with one another.
In accordance with an exemplary embodiment of the present invention, the application of a strong electric field to the oil will cause soot particulate agglomeration, thereby enhancing subsequent soot removal by centrifugation or other separation techniques. In one exemplary embodiment, the separation techniques may employ subsequent filtration using a filtration media, removal of an electrode or electrode for applying the electric field wherein soot has agglomerated or adhered to the electrode itself or any combination of the foregoing processes. In accordance with an exemplary embodiment, the process of electro-agglomeration will cause the average soot particulate size to increase. This will cause an increase of the sedimentation rate upon application of a centrifugal force or other filtration technique.
In accordance with an exemplary embodiment, the lubricating oil containing soot is positioned between two electrodes connected to a DC power supply. Alternatively, an AC power supply may be employed. A direct current of up to 25 kV is applied to the electrodes. Of course, currents greater or less than 25 kV may be used. The resulting strong electrical field will cause the soot to agglomerate on the positive electrode. The agglomerated soot may then be actively removed. In one exemplary embodiment, the positive electrode with the agglomerated soot may be simply removed and this electrode is either discarded or cleaned, wherein a new electrode or the cleaned electrode is replaced into the oil filtration device, which in one embodiment may comprise an oil filter mounted on an internal combustion engine for example, a diesel engine wherein soot removal from the oil is desirable.
In another exemplary embodiment and by simply removing the electric field a partial or passive deagglomeration may result, wherein the partially agglomerated soot will then be separated from the liquid oil phase by centrifugation or other separation method, which may include filtration through filtration media.
In accordance with an exemplary embodiment, a voltage potential is applied to electrodes connected to an AC or DC power supply. In one non-limiting example, a voltage potential of up to 25 KV is applied to the electrodes. The strong electric field will cause the soot to agglomerate on the positive electrode if the current applied is direct. This approach can serve as an effective means of reducing the soot level in the circulating oil and entails no further purification or post separation scheme. However, a portion of the soot remaining in the liquid phase that is not collected on the electrode has been demonstrated to be preagglomerated resulting in a larger average particle size or diameter. This larger average particle diameter allows for the soot to be trapped by a filtration media of a filter disposed in a flow path of a filter constructed in accordance with the teachings of exemplary embodiments of the present invention.
Also and in some instances, no agglomeration on the electrode is observed if the applied voltage is alternating in nature. The partially agglomerated or preagglomerated soot not collected on the electrode (e.g., AC or DC current) can then be separated from the liquid oil phase by centrifugation or other downstream separation method.
The attached Figures illustrate various exemplary embodiments of the present invention. In one embodiment and upon exposure to a strong electrostatic field particles will pre-agglomerate or clump prior to or during a process of migration to the positive electrode. This will result in larger average particle size and would likely increase sedimentation rate of the particles.
In one alternative embodiment and for separation by filtration, this mechanism would likely require the use of alternating current in order to return agglomerates to the oil flow for downstream separation by centrifugation.
In accordance with an exemplary embodiment of the present invention the effect of electro-agglomeration was studied on centrifuge separation, soot levels over time and TBN.
In a first example a time-base study of the effect of an electric field on a sedimentation rate was performed wherein electrode soot loadings were observed.
The effect of electro-agglomeration on TBN is illustrated in
Referring in particular to
In accordance with an exemplary embodiment of the present invention the filter housing is configured to allow removal and replacement of at least the positive electrode. For example, the housing will comprise a removable cap to access the chamber. In one embodiment, the positive electrode is removable for cleaning and replacement or it is removed and discarded while a new positive electrode is inserted into the filter wherein the new positive electrode is easily coupled to the power supply. In one exemplary embodiment, the power supply is integral with the engine or system the oil filter is fluidly coupled to. Furthermore, the power supply can be easily connected and disconnected from the filter housing and/or the electrodes to allow removal and replacement of the filter and/or the positive electrode. In one exemplary embodiment, the filter and housing may be totally removed and replaced or the filter housing is integral with the engine and comprises a cap for access into the chamber of the housing, wherein the electrode(s) are removed. Also, and as discussed above, as the soot agglomerates on the positive electrode the current levels decreased thus, a measurement of the current via an amp meter can be used to determine when to remove and replace the positive electrode namely, the observed current will indicate when the filter needs to be replaced.
In one alternative embodiment and for separation by filtration via a filter media, this mechanism would likely require the use of alternating current in order to return agglomerates from the positive electrode to the oil flow for downstream separation by centrifugation or filtration by a filter media. Alternatively, and with a DC current the filter media can be employed to capture soot particles not captured on the positive electrode.
In one alternative exemplary embodiment and as illustrated by the dashed lines in
Referring in particular to
In one alternative exemplary embodiment and as illustrated by the dashed lines in
In another alternative embodiment, the filter further comprises a rotatable member 40 (See also
In one alternative exemplary embodiment, the electrode arrangements may include a metallic mesh serving as the positive electrode and may be formatted in a spiral wound, pleated, concentric or stacked plate arrangement. The positive electrode might also be in the form of a conducting fiber packed into a fixed-bed flow arrangement. In another alternative embodiment and referring to
In another embodiment, the filtering process is facilitated by filtering the larger diameter or size soot particles through a filtration media of the mechanical filter element, wherein the soot particles are disposed upon a surface of the filtration media. The filtration media being any media capable of providing the desired results (e.g., cellulose, nylon, synthetic or equivalents thereof).
Also illustrated in
In accordance with an exemplary embodiment, the filter may comprise only the pair of electrodes with at least one removable electrode. Alternatively, the filter will comprise the pair of electrodes and a filtration media configured to filter the larger diameter preagglomerated soot particles. In yet another alternative embodiment, the filter will comprise the pair of electrodes and a rotatable element for applying a centrifugal force to the preagglomerated soot particles and a removable surface for collecting the preagglomerated soot particles. In yet another alternative exemplary embodiment, the rotating element and the positive electrode are combined or are one in the same. In still yet another alternative embodiment, the filter will comprise the pair of electrodes, a filtration media configured to filter the larger diameter preagglomerated soot particles and a rotatable element for applying a centrifugal force to the preagglomerated soot particles having a removable surface for collecting the preagglomerated soot particles.
In accordance with an exemplary embodiment, the lubricating oil containing soot is allowed to flow between two electrodes connected to either a DC or AC source of current. Upon application of an electric current, the soot will collect on the positive electrode to very high levels under certain conditions and electrode arrangements. The electrode arrangements may include a metallic mesh serving as the positive electrode and may be formatted in a spiral wound, pleated, concentric or stacked plate arrangement. The positive electrode might also be in the form of a conducting fiber packed into a fixed-bed flow arrangement. The rotating element in a centrifuge may also serve as the positive electrode, thus combining electrostatic with centrifugal separation in a single electromechanical device. The oil flow to the soot removal device might be either a full flow or bypass flow with or without further downstream separation.
For example, and as illustrated in
In accordance with an exemplary embodiment of the present invention the filters may be connected in series or alone as stand alone filters, wherein each of the filters are in fluid communication with each other via an oil circulation system. For example, the system may comprise only one filter (
In any of these embodiments, the power supply is removably secured to the oil filter to allow removal and replacement of the oil filter wherein the filter itself is simply replaced or the electrodes of the filter are replaced. In one exemplary embodiment, the power supply is electrically coupled to a power supply of a vehicle having an engine with the oil system requiring filtration.
One non-limiting example of a filter similar to filter 100 is found in U.S. patent application Ser. No. 11/626,476 filed Jan. 24, 2007, the contents of which are incorporated herein by reference thereto. It being understood that this filter may be in series with other filters (e.g., filter 70 and filter 120) wherein each of the filters are in fluid communication with an oil or the components of filter 100 can be incorporated into a filter having a pair of electrodes and in one alternative one of the electrodes may comprise a portion of the centrifuge of the filter. For example, and as illustrated by the dashed lines in
While the invention has been described with reference to an exemplary embodiment, 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 embodiment 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 appended claims and their legal equivalence.
This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/825,397 filed Sep. 12, 2006, the contents of which are incorporated herein by reference thereto.
| Number | Date | Country | |
|---|---|---|---|
| 60825397 | Sep 2006 | US |
