Patent Application
20130199983
An oil filter containing a continuous release additive vessel that releases an additive into the oil to extend oil drain intervals.
Current lubricating oils do not meet the engine manufacturer's desired oil drain intervals because of limits in ash content placed upon the latest oil category. The inability of the oil to remain useful for extended service intervals is due to multiple changes in both the oil and the engine over the past few years. For example, many modern diesel engines are now equipped with exhaust gas recirculation (EGR) systems and diesel particulate filters (DPF), have reduced oil sump volumes, use lower viscosity oils, and use ultra low sulfur diesel (ULSD) and alternative fuels or coolants (including non-aqueous), all of which change the operating conditions of the engine and the rate of oil degradation.
The latest oil category, CJ-4, CI-4, limits the ash and sulfur content of new oil to 1.0% and 1.5%, respectively, which in turn limits the amount of high performance anti-wear additives (for example zinc dialkyldithiophosphates (ZDDP)) and over-based detergents (for example magnesium or calcium sulfonate or salicylate) because of the metal present in the chemical composition. It is expected that these limits will continue to decrease or at least remain the same as future oil categories are launched, continuing to limit the oil manufacturer's abilities to extend the oil's useful life.
The need for additional additives is driven by the reactions occurring in the crankcase of a diesel engine. The primary limiting factor of oil life that is most commonly seen is the inability for the total base number (TBN) to remain above the condemning limit of 2.5 mgKOH/g or alternatively at a level higher than that of the total acid number (TAN). This can be due to a variety of chemical reactions that occur in the crankcase including oxidation of the oil from high temperature and pressure environments, and the formation of both strong and weak acids in the oil from fuel blow-by (including biodiesel), coolant leaks, moisture and other contamination, sludge or soot formation and a variety of other mechanism.
Weak acids (such as acetic acid, methyl acetate, ethyl acetate, carboxylic acids, etc.) are formed due to the blow-by of combustion products of biodiesel based fuels. These acids are best neutralized by weak bases (such as metal oxide or methyl amine). Strong acids are also formed and are best neutralized by strong base material in the oil thus depleting the initial TBN value.
Other reasons preventing the oil from reaching the desired drain intervals include thickening or thinning of the oil viscosity (e.g. maximum excursion equals±one grade), the inability to disperse soot and particulates in the oil, and excessive nitration. With the past oil category, CI-4, ash content of up to 1.5% was acceptable with no limit on the sulfur content. This allowed an additive to include higher levels of over-based detergent and other additives and reach longer service intervals. Because additives are depleted continuously over time in the oil in part due to acid neutralization and by reacting with peroxides (a product of oxidation) generated in the engine oil, an improved technique of continually metering additives into the oil to extend the oil's useful life would be useful.
An engine oil filter is described that will continually release highly concentrated additives into the engine oil to reduce maintenance costs by reducing oil usage through extended oil drain intervals. The additives may include, but are not limited to, overbased detergents, weak base materials, anti-oxidants, anti-wear additives, friction modifiers, dispersants, viscosity modifiers, anti-foam additives, nano additives, or other additives beneficial to engine oil, individually or in various combinations.
In one embodiment, the oil filter includes a housing defining an interior chamber and having a first end and a second end, an oil inlet and an oil outlet at the first end of the housing, and oil flow pathway between the inlet and the outlet for oil flowing through the interior chamber. Filter media is disposed within the interior chamber in the oil flow pathway between the inlet and the outlet, and the filter media is configured to filter oil flowing through the interior chamber. An additive vessel is disposed in the interior chamber and is configured to introduce additive material contained therein into oil flowing through the interior chamber.
In one embodiment, the additive material includes an over-based detergent and optionally one or more of: a weak base additive, an anti-oxidant additive, an anti-wear additive, a friction modifier additive, a dispersant additive, an anti-foam additive, a nano-additive, a corrosion inhibitor additive, a pour point depressant additive and a surfactant additive. For example, in one example, the additive material comprises the over-based detergent for example in an amount ranging from about 10% to about 90% by weight of the additive material, a friction modifier additive for example in an amount ranging from about 0.2% to about 3% by weight, an anti-oxidant additive for example in an amount ranging from about 0.5% to about 3% by weight, an anti-wear additive for example in an amount ranging from about 1.0% to about 5% by weight, and an inert solvent for example in an amount ranging from about 0 to about 88.3% by weight.
Other additives and additive amounts can be used depending upon factors including, but not limited to, the type of oil, the oil category, the properties of the oil that one wants to improve, and the effectiveness of the additive(s). The additives can be used singly by themselves or in a multi-component mixture at any desired ratio. The additives may be combined with an inert solvent, such as base oil, for viscosity adjustment.
In one embodiment, the oil filter includes a full flow pleated filter media, a by-pass media, a venturi nozzle, and the additive vessel which continuously releases an oil additive into the oil flowing through the oil filter. However, other combinations of elements are contemplated including, but not limited to: a) an oil filter containing the full flow pleated media, a venturi, and the additive vessel; b) by-pass media and the additive vessel; and c) a full flow pleated filter media, a by-pass media, and the additive vessel.
With reference to
Next to the filter element 18 is a by-pass filter media section 24. The by-pass filter media 24 can comprise, for example, an assembly of stacked, ring-shaped discs made of, for example, cellulose material. The by-pass filter media 24 is configured to filter the oil as the oil flows through the by-pass media toward a central oil passageway 26 thereof. The by-pass filter media 24 abuts up against the lower endplate 20 and includes an enclosing base endplate 28. The filter 10 may include any ratio of full flow filter media 18 to by-pass filter media 24.
The filter element 18 includes an inner sleeve 30 that supports the interior surface of the filter media and defines an interior space 32. The lower endplate 20 is open at its center and is formed with a short, cylindrical conduit 34 that extends upwardly into the interior space 32. A tube 36 fits around the conduit 34 and provides fluid flow communication from the central oil passageway 26 of the by-pass filter media 24 into a venturi nozzle 38 disposed within the interior space 32.
The upper endplate 22 is formed with an inner annular lip 40 which provides an anchor for an inner seal 42. The venturi nozzle 38 includes an outwardly flared end that fits around the inner annular lip. When the filter 10 is mounted during use, an inside annular surface of the inner seal 42 fits up against a stem of a filter head as described in U.S. Pat. No. 5,906,736. The nut plate 16, which may be stamped, molded, or machined, is internally threaded and is assembled to an externally-threaded portion of the filter head.
The housing 12 is metal and has a substantially cylindrical sidewall which includes a formed upper lip which is shaped with an inverted receiving channel. Tightly and securely anchored into the channel is an annular upper, outer lip of the nut plate 16.
The nut plate 16 is provided with at least one oil inlet opening 48 to allow oil to be filtered to enter the filter. The nut plate 16 also defines a central, threaded outlet opening 50 by which the filter is threaded onto a corresponding threaded mounting post on the filter head and through which oil exits the filter. Further details on the general construction and operation of this type of filter can be found in U.S. Pat. No. 5,906,736 which is incorporated herein by reference in its entirety.
An additive vessel 60 is disposed within the chamber 14 next to the by-pass filter media 24 between the by-pass filter media and the second end of the housing 12. The additive vessel 60 contains one or more additive materials and is configured to continuously release the additive into the oil at a controlled rate.
A coil spring 62 within the housing 12 pushes directly or indirectly against the bottom of the additive vessel 60 which forces the additive vessel 60 into engagement with the endplate 28.
The additive(s) released into the oil are intended to improve oil quality in some manner including, but not limited to, replenishing reserve alkalinity (RA), reducing oxidation and wear, stabilizing oil viscosity, and/or neutralizing acids in the oil. One example by which an additive may improve an oil's useful life is illustrated through the reaction of a sulfonate and carboxylate acid to create a neutral salt and water as shown below, thus preventing the TAN of the oil from increasing.
The additive may include, but is not limited to, any of the following additives which may be combined with a base oil or solvent for viscosity adjustment:
The percentages in Table 1 are by volume or by weight. One or more of the listed additives may be blended with an inert solvent, such as base oil, to reach 100% composition. The listed additives can be used individually as one pure additive or in any combinations to form a multi-component mixture at any ratio.
One exemplary embodiment of a multi-component additive mixture that is believed to be useful is listed in Table 2 (by volume % or by weight %), which may or may not be mixed with an inert solvent such as a base oil to adjust viscosity.
Tables 3-6 shown below indicate possible additive compositions for the additive vessel. All compositions and treat rates (TR) are in % by volume or % by weight (both are applicable). The mixtures below may also be blended with an inert solvent, such as base oil, to reach 100% composition.
With reference to
The vessel 60 utilizes the pressure gradient across the filter element in addition to the vacuum effect created by the venturi 38 on the clean side of the pleated filter media 18 to drive the additive up the capillary tube 72 and into the oil. The release rate of the additive is controlled by careful selection of the capillary inner diameter (release rate goes with fourth power of inner diameter ID) and capillary length (release rate goes with inverse proportion of length) according to the well-known Hagen-Poiseuille equation for laminar flow in capillary tubes:
where;
The difference between P1 and P2 changes over the life of the filter 10 as the filter media becomes more plugged. However, P1 will always be greater than P2. As P1−P2 increases, the additive release rate will also increase, thus compensating for the dilution of the additive.
Approximately 85-95% of the oil flows through the filter media 18, and most of the remainder flows through the by-pass media 24 except for the small amount that flows into the additive vessel.
The very small inner diameter of the capillary tube 72 makes it intolerant of particulates which may plug or damage the tube. Therefore, the additive(s) in the vessel 60 is in liquid form.
The venturi 38 helps to drive flow through the capillary tube 72. In addition, it is beneficial if the by-pass filter media not include additive material intended to be introduced into the oil. The use of a stationary additive material in the by-pass filter media section can lead to a decrease in media capacity due to reduced porosity. Therefore, eliminating an additive material from the by-pass media would allow for equivalent capacity using a reduced by-pass media area, thus allowing for a larger chemical vessel. In addition, using a liquid additive in the vessel 60 will have improved reactivity when compared to use of a stationary additive in the by-pass media due to the fact that the active sites of an additive chemical contained in the by-pass media become coated with soot, sludge, and other contaminants and therefore have a reduced ability to neutralize acids. Nonetheless, if one finds it advantageous to do so, the by-pass media or the full flow filter media may include an optional stationary additive material, for example a strong or weak base additive material in particulate form, intended to be introduced into the oil.
Also, the central oil passageway 26 in the by-pass media is advantageous. Without this open flow path, the pressure across the capillary tube will be very similar on the dirty side and clean side, so there will be no force to drive liquid flow through the capillary. The lack of such a central passageway 26 also minimizes the effect of the venturi tube 38 on the additive vessel, further hindering the driving force of the flow.
While the filter 10 has been described with the additive vessel at the bottom of the filter, the filter 10 can include other configurations such as with the additive vessel in other locations in the filter, for example located between the by-pass media 24 and the full flow media 18.
In addition, although the filter 10 has been described as having a combination of the full flow filter media 18, the venturi 38, the by-pass media 24, and the additive vessel 60, other configurations are possible. For example, the filter can include the full flow pleated media 18, the venturi 38, and the additive vessel 60, without the by-pass media. In another example, the filter can include the by-pass media 24 and the additive vessel 60 without the pleated media 18. In another example, the filter can include the full flow pleated filter media 18, the by-pass media 24, and the additive vessel 60, without the venturi nozzle 38 and the sleeve 30. Other configurations and combinations of elements are possible.
The invention may be embodied in other forms without departing from the spirit or novel characteristics thereof. The embodiments disclosed in this application are to be considered in all respects as illustrative and not limitative. The scope of the invention is indicated by the appended claims rather than by the foregoing description; and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.
| Number | Date | Country | |
|---|---|---|---|
| 61595326 | Feb 2012 | US |
