Patent Application
20120031760
This application relates to an apparatus and method for removing soot, sludge and other insoluble particulates from lubricating oils, and more particularly this application relates to particulate 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, sludge and other insoluble particulates from the oil.
Disclosed herein is an apparatus and method for removing soot, sludge and other insoluble particulates from the engine oil. In one exemplary embodiment, a method for removing the particulates from an engine oil is provided, the method comprising: disposing an oil containing the particulates between a pair of electrodes, wherein one of the electrodes is a positive electrode; wrapping a media on the positive electrode, wherein the media is configured to collect a portion of the particulates drawn towards the positive electrode; applying an electric current to the electrodes for a period of time, wherein portions of the particulates agglomerate in the media and removing the agglomerated particulates from the oil.
In another embodiment, a method for removing soot from engine oil is provided, the method including the steps of: 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 size of the soot particles; and removing the soot particles by a filtering process, wherein the filtering process comprises application of a centrifugal force to the oil, wherein the centrifugal force causes the soot particles to be disposed in a media disposed on one of the pair of electrodes that is removable from the oil.
In another embodiment, a filter for removing soot particles from an engine oil having soot particles disposed therein is provided, the filter having: 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 electrodes being disposed in the flow path after the inlet, the pair of electrodes being electrically coupled to a DC current, wherein an electric field 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, wherein at least the positive electrode is removable from the filter to allow removal of the soot particles agglomerated on the positive electrode; and a media applied to the surface of the positive electrode, wherein the media is configured to improve the collecting efficiency of the agglomerated portion of soot particles on the positive electrode.
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.
A disadvantage to the use of centrifugal methods for soot and/or particulate removal is the relatively low efficiency as currently practiced. In accordance with an exemplary embodiment of the present invention methods and apparatus for soot, sludge and other insoluble particulates 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. One non-limiting example of such an oil filtration device is found in U.S. patent application Ser. No. 11/854,295 filed Sep. 12, 2007, the contents of which are incorporated herein by reference thereto. Thereafter, the agglomerated soot and/or other particulates are removed via removal of a particulate-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. Reference is also made to U.S. Patent Application Publication No. 2008/0060949 the contents of which are incorporated herein by reference thereto.
In accordance with an exemplary embodiment of the present invention, the application of a strong electric field to the oil will cause particulate agglomeration, thereby enhancing subsequent 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 electrodes, that apply the electric field when particulates have 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 or other particulate size to increase. This will cause an increase of the sedimentation or collection rate upon application of a centrifugal force or other filtration technique.
In accordance with an exemplary embodiment, the lubricating oil containing soot, sludge and other insoluble particulates is positioned between two electrodes connected to a DC power supply. A direct current of up to 5 kV is applied to the electrodes. Of course, currents greater or less than 5 kV may be used. The resulting strong electrical field will cause the soot, sludge and other insoluble particulates from the oil to agglomerate on the positive electrode. To enhance particulate agglomeration, a coating is applied to the surface of the positive electrode, wherein the coating is a soot-collecting agent having properties and configured to improve the collecting efficiency of the agglomerated soot or other particles on the positive electrode. The agglomerated particles may then be actively removed. In one exemplary embodiment, the positive electrode with the agglomerated particles may be simply removed and this electrode is either discarded or cleaned. 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 particulates 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 electric power supply. In one non-limiting example, a voltage potential of up to 5 kV or less is applied to the electrodes. Of course, voltage potentials greater or less than 5 kV may be used. The strong electric field will cause the soot to agglomerate on the positive electrode. To enhance soot or other particle agglomeration, a coating is applied to the surface of the positive electrode, wherein the coating is a soot-collecting agent having properties and configured to improve the collecting efficiency of the agglomerated of soot particles on the positive electrode. 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 or other particulates 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 particulates to be more efficiently 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, however agglomeration does occur in the circulating oil. The partially agglomerated or preagglomerated soot not collected on the electrode 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 electrical 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 and collection 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 maintain agglomerates in 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 coating 11 applied to the surface of the positive electrode may include as components, soot particles extracted from lubricating oil, carbon black from acetylene, soot purchased commercially, activated carbon powder, oil-absorbing polymer, other soot-collecting agents or a combination thereof. Here, the coating is adhered to the surface of the positive electrode using a suitable adhesive material or the like.
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 may 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 decrease. Measurement of the current via an amp meter may help 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 only, this mechanism would likely require the use of alternating current in order to maintain agglomerates in 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
For example, and in one embodiment, the filter comprising the housing is a screw on type of filter wherein the entire housing comprising the electrodes is removed and replaced. Alternatively and when the housing is integral with the engine, the housing has a cap portion that is removed and the electrodes are simply removed and, if applicable, the filter media is also removed.
Referring in particular to
In one alternative exemplary embodiment, and as illustrated by the dashed lines in
In another alternative embodiment, also shown in
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 may also be in the form of a conducting fiber packed into a fixed-bed flow arrangement. Alternatively, the positive electrode may be formed of stainless steel, copper, aluminum, platinum or other electrically conducting material. In one exemplary embodiment of the present invention, the surface of the positive electrode has a coating applied, wherein the coating is a soot-collecting agent such as soot particles extracted from lubricating oil, carbon black from acetylene, soot purchased commercially, activated carbon powder, oil-absorbing polymer, other soot-collecting agents or a combination thereof configured to improve the soot-collecting efficiency on the surface of the positive electrode. 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 an electric 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. Alternatively, the positive electrode may be formed of stainless steel, copper, aluminum, platinum or other electrically conducting material. In one exemplary embodiment of the present invention, the surface of the positive electrode has a coating applied, wherein the coating is a soot-collecting agent such as soot particles extracted from lubricating oil, carbon black from acetylene, soot purchased commercially, activated carbon powder, oil-absorbing polymer, other soot-collecting agents or a combination thereof configured to improve the soot-collecting efficiency on the surface of the positive electrode. The rotating element in a centrifuge may also serve as the positive electrode, thus combining electrostatic with centrifugal separation in a single electro-mechanical device. The oil flow to the soot removal device may 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
Referring now to
Accordingly, the soot removal helps maintain the oil viscosity for an extended period of time and improves the wear characteristics of the oil. Current technologies with soot removal efficiencies of less than 20% do not provide an efficient enough soot removal solution to generate any significant extension of the oil drain intervals for the fleets.
Referring now to
In this embodiment an electric field is provided between two electrodes, one of which is wrapped by a media, which in one embodiment will comprise multiple layers of media to remove soot particles from the lubrication oil. Non-limiting examples of suitable media include but are not limited to the following examples: 1) woven and nonwoven fibrous materials, comprising any one of the following or combinations thereof organic fibers, natural or synthetic fibers made from cellulose, polyolefins, polyesters, polyamides; inorganic fibers, metallic and ceramic fibers, stainless steel fibers, alumina and spun glass and silica fibers; 2) open cell organic and inorganic foams made from polyurethanes, polyolefins, polyesters, polyamides; sintered ceramics, alumina or silica; and combinations thereof; and 3) electrodes mechanically surrounded by fine particles (particles kept within a cage or a screen which provides the voids) and fine particles of alumina, silica etc.
Accordingly, the soot particles agglomerate due to the generated electric field and move towards the media covered electrode. The wrapped media provides a structural support for the soot to grab onto and prevents the soot from sliding down the electrodes. The soot collection in one embodiment will mostly be in the media rather than on the media surface.
In one implementation the lubrication oil is flowed through the filter between two electrodes one of which is wrapped with the filter media. The electrode configuration could be two concentric cylinders (See at least
Once the media is saturated with soot the cartridge consisting of the media wrapped soot gathering electrode can be replaced with a new one. Alternatively, the media may be left in the filter provided that the media has enough capacity to entrain the soot particles therein. The graphs of
In one embodiment the intensity of the electric field is varied. For example and as illustrated in at least
As discussed above, the lubrication oil is flowed through the filter between the two electrodes one of which may be wrapped with the filter media. The electrode configuration could be two concentric cylinders or other alternate configuration and the electrode distances can be reduced as compared to applications with stronger electric fields. The low strength electric field is generated either using an external power (lower than 3 kV) source or by developing in-situ using piezoelectric materials or other alternatives.
Upon application of the electric field the soot will start migrating and collecting around the soot gathering electrode. If media is used, the media will have to be replaced once it saturated with soot. Alternatively, both the soot collecting electrode and the media are removed and replaced.
In summary, there are at least several components to the soot removal process 1) generation of the electric field; 2) configuration of the electrically charged materials; and 3) stabilization of the debris cake.
Various ways may be employed to develop the electric field, which include but are not limited to the following methods/concepts: use of metallic electrodes within the oil's flow path which are connected to an external power supply; configuring piezoelectric materials into a flow path whereby the charge can be developed on the surface of the material by the cyclic pressure change developed during the course of filter's operation; use of thermoelectric materials which develop an electrical potential when brought up to a specified temperature; use of material partners which develop a triboelectric charge when these opposite materials (on the triboelectric scale) move or rub against each other against each other; and use of permanently charged materials, like fibrous materials, which have been previously charged through such processes like corona discharge, commonly called electrets.
The configuration of the electrically charged materials may be achieved by the following non-limiting methods and/or concepts: two electrodes or materials which possess/generate the electric charge are brought into close proximity so that the distance for migration is small in comparison to the mean free path of the suspended particles for example, electrodes parallel to the flow or perpendicular to the flow and wherein the collection zone and the electric field is perpendicular to the flow or the collection zone is within the flow past the non collection electrode so to speak parallel to the flow; and having the electrified materials in a woven or nonwoven format or a solid structure.
The stabilization of the debris cake may be achieved in one non-limiting manner by stabilizing the collected gel debris cake from the competing dissolution process by incorporating a porous media to provide static zones that can stabilize the collected cake. This concept may have more relevance when working with lower voltages and hence lower driving force configurations. Here the electrode(s) are surrounded by a porous material, either an open cell foam, fibrous woven or nonwoven material or any structure which can provide a tortuous continuous path to the electrode, wherein the size of the pores are sufficient to allow for unimpeded electrical migrational diffusion but small enough to prevent turbulence and dissolution of the gel cake.
In addition, this embodiment and others disclosed herein are also contemplated for use in gasoline passenger car applications to remove particulate debris from the lube oil including fine inorganic dust and sludge components resulting in an extension of the oil change interval.
The below Tables illustrate various trials utilizing the soot removal techniques and apparatus for various embodiments disclosed herein.
ot1.074
ot1.077
ot1.080
ot1.081
ot1.082
ot1.083
ot1.084
ot1.085
ot1.086
ot1.087
ot1.088
ot1.089
ot1.090
ot1.091
ot1.092
ot1.093
ot1.106
ot1.107
ot1.108
ot1.112
ot1.111
ot1.123
ot1.125
ot2.049
ot1.157
ot1.158
ot1.159
ot1.160
ot1.161
ot1.171
ot1.183
ot1.184
ot1.185
ot1.198
ot1.170
ot1.195
ot1.196
ot1.197
ot1.198
ot1.199
ot1.200
ot1.201
ot1.202
ot1.204
ot1.205
ot1.206
indicates data missing or illegible when filed
t.670
t.671
t.672
t.673
t.674
t.675
t.676
t.677
t.678
t.679
t.680
t.681
t.682
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t.685
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t.688
t.689
t.690
t.691
t.692
t.693
t.694
t.695
t.696
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t.701
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t.712
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t.716
t.718
t.719
t.720
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t.723
t.724
t.725
t.734
t.736
t.737
t.738
t.739
indicates data missing or illegible when filed
Exemplary implementations include onboard transportation applications as well as static applications to control the soot levels in lubricating oils. 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. 61/333,239 filed May 10, 2010, the contents of which are incorporated herein by reference thereto. This application also claims the benefit of U.S. Provisional Patent Application Ser. No. 61/470,214 filed Mar. 31, 2011, the contents of which are incorporated herein by reference thereto. This application is a continuation in part of U.S. patent application Ser. No. 12/606,711, filed Oct. 27, 2009, which claims the benefit of U.S. Provisional Patent Application Ser. No. 61/108,632 filed Oct. 27, 2008 the contents each of which are incorporated herein by reference thereto. This application is also a continuation in part of U.S. patent application Ser. No. 11/854,295 filed Sep. 12, 2007, which claims the benefit of U.S. Provisional Patent Application Ser. No. 60/825,397 filed Sep. 12, 2006, the contents each of which are incorporated herein by reference thereto.
| Number | Date | Country | |
|---|---|---|---|
| 61470214 | Mar 2011 | US | |
| 61333239 | May 2010 | US | |
| 61108632 | Oct 2008 | US | |
| 60825397 | Sep 2006 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 12606711 | Oct 2009 | US |
| Child | 13104550 | US | |
| Parent | 11854295 | Sep 2007 | US |
| Child | 12606711 | US |
