Crankcase ventilation filter assembly with rotating filter element and stationary filter element

Abstract

A crankcase ventilation filter assembly includes a housing. The crankcase ventilation filter assembly includes a rotating filter element positioned at least partially within the housing. The rotating filter element includes a first filter media configured to rotate within the housing and is structured for axial flow of a fluid through the first filter media. The crankcase ventilation filter assembly includes a stationary filter element positioned at least partially within the housing. The stationary filter element includes a second filter media positioned radially outward from the first filter media and is structured for inside-out radial flow of the gas through the second filter media. An air gap is defined between the second filter media and the housing such that fluid exiting the second filter media flows through the air gap and out of the crankcase ventilation filter assembly.

Description

CRANKCASE VENTILATION FILTER ASSEMBLY WITH ROTATING FILTER ELEMENT AND STATIONARY FILTER ELEMENTCROSS-REFERENCE TO RELATED APPLICATIONS1000.11 The present application claims priority to United States Provisional Patent Application No. 63 / 540,731, filed September 27, 2023. The contents of this application are incorporated herein by reference in their entirety.TECHNICAL FIELD[0002 [ The present disclosure relates generally to filters for use with internal combustion engine systems.BACKGROUND[00031 During operation of an internal combustion engine, a fraction of combustion gases can flow out of the combustion cylinder and into the crankcase of the engine. These gases are often called “blowby” gases. The blowby gases include a mixture of aerosols, oils, and air. If vented directly to the ambient, the aerosols contained in the blowby gases can harm the environment. Accordingly, the blowby gases are often routed out of the crankcase via a crankcase ventilation system. The crankcase ventilation system may pass the blowby gases through a coalescer (i.e., a coalescing filter element) to remove a majority of the aerosols and oils contained in the blowby gases. The filtered blowby gases (“clean” gases) are then either vented to the ambient (in open crankcase ventilation systems) or routed back to the air intake for the internal combustion engine for further combustion (in closed crankcase ventilation systems).[00041 Some crankcase ventilation systems utilize rotating crankcase ventilation filter elements, for example, rotating coalescer elements that increase the filter efficiency of crankcase ventilation systems by rotating the coalescer element during filtering. In rotating coalescer elements, the contaminants (e g., oil droplets suspended and transported by blowby gases) are separated at least in part by centrifugal separation techniques. Additionally, therotation of the coalescer element can create a pumping effect, which reduces the pressure drop through the crankcase ventilation system.SUMMARY|0005] Embodiments described herein relate generally to crankcase ventilation filter assemblies that include a rotating filter element with an axial flow filter media and a stationary filter element positioned around the rotating filter element, the stationary filter element having a radial flow filter media. The radial flow filter media can facilitate inside-out radial flow.[0006| In one set of embodiments, a crankcase ventilation filter assembly includes a housing. The crankcase ventilation filter assembly includes a rotating filter element positioned at least partially within the housing. The rotating filter element includes a first filter media configured to rotate within the housing and structured for axial flow of a fluid through the first filter media. The crankcase ventilation filter assembly includes a rotating and stationary filter element positioned at least partially within the housing. The stationary filter element includes a second filter media positioned radially outward from the first filter media and structured for radial flow of the gas through the second filter media. The radial flow of the gas can be an inside-out radial flow (e.g., the gas flows from a first position to a second position, wherein the first position is radially inward from a second position. An air gap is defined between the second filter media and the housing such that fluid exiting the second filter media flows through the air gap and out of the crankcase ventilation filter assembly.|0007] In another set of embodiments, a filter assembly comprising a housing, a rotating filter element positioned at least partially within the housing, and a stationary filter element positioned at least partially within the housing. The rotating filter element comprises a first filter media configured to rotate within the housing and structured for axial flow of a fluid through the first filter media, and an outer circumferential wall positioned radially outward of the first filter media. A lower end of the outer circumferential wall at least partially defines a rotating filter element exit point through which separated liquid drains from the rotating filter element. The stationary filter element comprises a second filter media positioned radially outward from the first filter media and the outer circumferential wall. The second filter mediais structured for inside-out radial flow of the fluid through the second filter media after passing through the first filter media. The stationary filter element further comprises a lower endcap coupled to a lower portion of the second filter media, the lower endcap including an inner ridge. The inner ridge at least partially defines a stationary filter element exit point through which separated liquid drains from the stationary filter element. A lower end of the outer circumferential wall is positioned axially lower than an upper edge of the inner ridge, thereby inhibiting separated liquid from flowing from the rotating filter element exit point into the stationary filter element.

[0008] It should be appreciated that all combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided such concepts are not mutually inconsistent) are contemplated as being part of the subject matter disclosed herein. In particular, all combinations of claimed subject matter appearing at the end of this disclosure are contemplated as being part of the subject matter disclosed herein.BRIEF DESCRIPTION OF THE DRAWINGS|0009] The foregoing and other features of the present disclosure will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings. Understanding that these drawings depict only several implementations in accordance with the disclosure and are therefore, not to be considered limiting of its scope, the disclosure will be described with additional specificity and detail through use of the accompanying drawings.

[0010] FIG. 1 is a side cross-section view of crankcase ventilation filter assembly, according to an example embodiment.[00111 Reference is made to the accompanying drawings throughout the following detailed description. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative implementations described in the detailed description, drawings, and claims are not meant to be limiting. Other implementations may be utilized, and other changes may be made, without departing from the spirit or scope of thesubject matter presented here. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the figures, can be arranged, substituted, combined, and designed in a wide variety of different configurations, all of which are explicitly contemplated and made part of this disclosure.DETAILED DESCRIPTION[00121 Embodiments described herein relate generally to rotating crankcase ventilation filter assemblies that include an axial flow filter media positioned around a hub coupled to a central shaft that is coupled to a motor. The filter media and the hub are secured between end caps that define an inner volume within which the filter media and the hub are secured.|0013[ Referring to the figures generally, various crankcase ventilation filter assemblies are described. The described filter assemblies can increase the number of particulates filtered out of the fluid, namely blow-by gases, generated by an engine by providing a two-stage filtration system. The first stage can include a rotating filter element structured for axial flow of a gas through a first filter media. The second stage can include a stationary filter element structured for radial flow (e.g., inside-out flow) of the gas through a second filter media. The stationary filter element can be positioned around the rotating filter element such that gas that has traveled through the rotating filter element can be filtered again to remove the remaining particles from the gas before exiting the filter assembly.

[0014] Rotating filter elements can remove a majority of particles from a blow-by gas from an engine, but the addition of the outer stationary filter element allows the filtration system to remove the particles that may be missed by the rotating filter element. This can further reduce the contaminants being released into the atmosphere in open crankcase ventilation systems or improve engine efficiency in closed crank case ventilation systems. For example, the rotating filter element and the stationary filter element can capture particles of all sizes, but the rotating filter element may be more efficient with larger particles and the stationary filter element may be more efficient with smaller particles. For example, the stationary filter element may be more efficient at capturing particles of <0.4 microns that a rotating filter element. Additionally, usingthe stationary filter element can reduce the complexity and cost that might be incurred when trying to achieve ultra-high efficiency with only a rotating filter element.|0015] Referring to FIG. 1, a cross-sectional view of a crankcase ventilation filter assembly 100 is shown, according to an example embodiment. The crankcase ventilation filter assembly 100 generally processes blowby gases received from an internal combustion engine crankcase to remove aerosols, oils, and other particulates contained in the crankcase blowby gases. The crankcase ventilation filter assembly 100 generally includes a housing 200 having an inlet 202 that receives crankcase blowby gases to be filtered, a central compartment 204, and an outlet 206 that provides filtered blowby gases to the internal combustion engine (in a closed crankcase ventilation system) or to the ambient (in an open crankcase ventilation system).[0016| The crankcase ventilation filter assembly 100 includes a drive shaft 208 that extends in an axial direction relative to the housing 200. The drive shaft 208 can extend at least partially through the central compartment 204 of the housing 200. At least a portion of the central compartment can be a chamber 210. The chamber 210 can be structured to receive and collect the oil and aerosols separated from the blowby gases. The housing 200 has at least one drain 212 structured to drain the separated liquid from the crankcase ventilation filter assembly 100 back to the engine.[00171 The crankcase ventilation filter assembly 100 includes a two-stage filtration system that includes a rotating filter element 300 and a stationary filter element 400. The rotating filter element 300 is positioned at least partially in the housing 200. In the embodiment of FIG 1, the rotating filter element 300 is a rotating coalescer element. The rotating filter element 300 can be any type of rotating coalescer. For example, the rotating filter element 300 can be electrically driven, hydraulically driven, mechanically driven, or pneumatically driven. The drive shaft 208 is coupled with the rotating filter element 300 to rotate the rotating filter element 300.[0018 [ The rotating filter element 300 includes a first filter media 302. The first filter media 302 is structured for axial flow of gas through the first filter media 302. For example, the first filter media 302 may have axial flow channels arranged in a direction generally parallel to anaxis defined by a drive shaft 208 of the crankcase ventilation filter assembly 100. Accordingly, the rotating filter element 300 is an axial flow coalescing element. In some arrangements, the first filter media 302 is a wound filter media. The first filter media 302 may be frustoconical in overall shape such that the axial flow channels are not arranged in a direction that is generally parallel to an axis defined by the drive shaft 208 of the crankcase ventilation filter assembly 100.

[0019] As shown in FIG. 1 (designated by the flow arrows), crankcase gas flows from the inlet 202, entering the first filter media 302 from a first, bottom end of the first filter media 302, through the first filter media 302 in an axial direction, and out a second, top end of the first filter media 302. Coalesced liquid (e.g., oil and aerosols separated from the crankcase blowby gas) passes through the layers of first filter media 302, and separated liquid drains to a bottom region of the rotating filter element 300, exiting through openings, shown as rotating filter exit points 304, at the largest local radius from a center axis of the rotating filter element 300 (e.g., the axis defined by the drive shaft 208). In some arrangements, the rotating filter element 300 is positioned in a manner such that gravity assists the draining of the separated liquid from the housing 200.

[0020] The rotating filter element 300 may include a drain lip 306. The drain lip 306 is defined by a diameter less than a diameter of an outer circumferential wall 308 of the rotating filter element 300. The drain lip 306 can be contiguous with, and extend inwardly from, the outer circumferential wall 308. The inward and upward extension of the drain lip 306 can mitigate outflow of coalesced / separated liquid from the first filter media 302 because the first filter media 302 is retained below the drain lip 306 and because the coalesced / separated liquid is biased radially outward (e.g., towards the outer circumferential wall 308, etc.) and therefore underneath the drain lip 306 towards the outer circumferential wall 308.

[0021] The stationary filter element 400 of the crankcase ventilation filter assembly 100 is positioned at least partially within the housing 200. The stationary filter element 400 includes a second filter media 402. The second filter media 402 can be various types of media. For example, the second filter media 402 can be pleated, a meltdown polymer, include single ormultiple layers of glass, include nano-fiber layers, or any combination thereof. The second filter media 402 is positioned radially outward from the first filter media 302. The second filter media 402 extends around the first filter media 302. The second filter media 402 can have any shape that extends around the first filter media 302. For example, the second filter media 402 can be cylindrical or non-cylindrical. The second filter media 402 is structured for radial flow (e.g., inside-out flow) of the gas through the second filter media 402. For example, after the blowby gas exits the rotating filter element 300, the blowby gas can flow radially through the second filter media 402 to remove remaining particles from the blowby gas.

[0022] The second filter media 402 is positioned away from an outer wall of the housing 200 such that there is an air gap 404 between the second filter media 402 and the housing 200. The air gap 404 allows the blowby gas to flow through the second filter media 402 and out of the crankcase ventilation filter assembly 100 via the outlet 206 of the housing 200. The second filter media 402 extends across the outlet 206 such that the blowby gas that exits the rotating filter element 300 flows through the second filter media 402 of the stationary filter element 400 before exiting via the outlet 206. The second filter media 402 can be a coalescing filter media structured to retain the particles from the blowby gas and coalesce the particles into a film such that the particles can flow toward a bottom end of the second filter media 402 to be drained.|0023] The stationary filter element 400 includes a first endcap 406, shown as an upper endcap, and a second endcap 408, shown as a lower endcap. The second filter media 402 is coupled with the upper endcap 406 and the lower endcap 408. For example, the second filter media 402 can be potted (e.g., adhered to) or embedded (e.g., melted into) with the first endcap 406 and the second endcap 408. The upper endcap 406 can be coupled with an upper end of the second filter media 402.|0024] The upper endcap 406 includes a first sealing member 410. The first sealing member 410 can be structured to form a first seal between the upper endcap 406 and the housing 200. In the embodiment shown in Figure 1, the first sealing member 410 is positioned within a radially extending recess of the upper endcap 406 and is positioned so as to form a radially directed seal with the housing 200.

[0025] The lower endcap 408 includes a second sealing member 412. The second sealing member 412 can be structured to form a second seal between the lower endcap 408 and the housing 200. In the embodiment shown in Figure 1, the second sealing member 412 is positioned within a radially extending recess of the lower endcap 408 and is positioned so as to form a radially directed seal with the housing 200.[O026| The formed seals can be any type of seal, including but not limited to, a radial seal, an axial seal, or a contact seal. The first sealing member 410 and the second sealing member 412 are structured to form seals with the housing 200 that prevent gas from exiting the stationary filter element at a location other than the designated outlet 206. The first sealing member 410 and the second sealing member 412 can be any type of element configured to form a seal with the housing 200. For example, the first sealing members 410 and the second sealing member 412 can be elastomeric or non-elastomeric.|0027] The lower endcap 408 includes a base 414. The base 414 is structured to interface with and couple to the lower end of the second filter media 402. The lower endcap 408 includes an inner ridge 416 that extends a first distance from the base 414 toward an upper end of the second filter media 402. The lower endcap 408 includes an outer ridge 418 that extends a second distance from the base 414 toward the upper end of the second filter media 402. In some embodiments, the first distance can be less than the second distance. For example, the base 414, the inner ridge 416, and the outer ridge 418 can define a receptacle 420 configured to receive the liquid separated from the blowby gas via the second filter media 402. In the embodiment shown in FIG. 1, the outer ridge 418 defines a lower endcap radially directed recess, with the second sealing member 412 positioned therein.|0028J The stationary filter element 400 has at least one stationary filter exit point 422 for the separated liquid to exit the receptacle 420 and drain into a chamber 210. With the first distance being less than the second distance, an upper edge of the inner ridge 416 is lower than an upper edge of the outer ridge 418 such that the collected liquid will pool in the receptacle 420 and eventually flow over the inner ridge 416 and drain out of the stationary filter element 400 via a stationary drain 424. As such, the stationary filter exit point can be the upper edge of the innerridge 416. In some embodiments, the first distance may be the same or greater than the second distance such that the upper edge of the inner ridge 416 is level with or higher than the upper edge of the outer ridge 418. In such an arrangement, the inner ridge 416 may include at least one drain opening positioned a third distance away from the base 414. The third distance is less than the second distance of the outer ridge 418 such that the collected liquid can drain out of the receptacle 420 via the drain opening in the inner ridge 416. As such, the drain opening can be the stationary filter exit point 422.|0029] In some embodiments, the liquid separated from the blowby gas in the rotating filter element 300 and the liquid separated from the blowby gas in the stationary filter element 400 collect in the same chamber 210, i.e., the same chamber 210 is in separated liquid receiving communication with both the rotating filter element 300 and the stationary filter element 400, and drain out of the chamber 210 via the same drain 212. In other embodiments, the housing 200 may include a plurality of chambers 210 and drains 212. For example, the liquid from the rotating filter element 300 may exit the housing 200 via a first chamber 210 and first drain 212, and the liquid from the stationary filter element 400 may exit the housing 200 via a second chamber 210 and second drain 212.

[0030] The crankcase ventilation filter assembly 100 further includes a barrier 500. The barrier 500 is positioned at least partially between the first filter media 302 and the second filter media 402. The barrier 500 is structured to prevent liquid captured by the rotating filter element 300 from entering the stationary filter element 400. For example, the barrier 500 may cause the rotating element exit point 304 to be lower than the stationary filter exit point 422. For example, the barrier 500 may be a bottom end of the outer circumferential wall 308 of the rotating filter element 300. The end of the barrier 500 may be positioned axially lower than the upper edge of the inner ridge 416 of the lower endcap 408 such that the rotating element exit point 304 is positioned lower than the stationary filter exit point 422, thereby preventing or inhibiting the liquid from flowing from the rotating filter element 300 into the stationary filter element 400.

[0031] It should be noted that the term “example” as used herein to describe various embodiments is intended to indicate that such embodiments are possible examples, representations, and / or illustrations of possible embodiments (and such term is not intended to connote that such embodiments are necessarily extraordinary or superlative examples).[00321 The terms “coupled,” “connected,” and the like as used herein mean the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent) or moveable (e g., removable or releasable). Such joining may be achieved with the two members or the two members and any additional intermediate members being integrally formed as a single unitary body with one another or with the two members or the two members and any additional intermediate members being attached to one another.[003 1 It is important to note that the construction and arrangement of the various exemplary embodiments are illustrative only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described herein. Other substitutions, modifications, changes and omissions may also be made in the design, operating conditions and arrangement of the various exemplary embodiments without departing from the scope of the embodiments described herein.[0034| While this specification contains many specific implementation details, these should not be construed as limitations on the scope of any embodiment or of what may be claimed, but rather as descriptions of features specific to particular implementations of particular embodiments. Certain features described in this specification in the context of separate implementations can also be implemented in combination in a single implementation.Conversely, various features described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations andeven initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

Claims

WHAT IS CLAIMED IS:

1. A crankcase ventilation filter assembly, comprising: a housing; a rotating filter element positioned at least partially within the housing, the rotating filter element comprising a first filter media configured to rotate within the housing and structured for axial flow of a fluid through the first filter media; and a stationary filter element positioned at least partially within the housing, the stationary filter element comprising a second filter media positioned radially outward from the first filter media and structured for inside-out radial flow of the gas through the second filter media; wherein an air gap is defined between the second filter media and the housing such that fluid exiting the second filter media flows through the air gap and out of the crankcase ventilation filter assembly.

2. The crankcase ventilation filter assembly of claim 1, wherein the stationary filter element further comprises: an upper endcap coupled with an upper end of the second filter media, the upper endcap comprising a first sealing member structured to form a first seal with the housing; and a lower endcap coupled with a lower end of the second filter media, the lower endcap comprising a second sealing member structured to form a second seal with the housing.

3. The crankcase ventilation filter assembly of claim 1, wherein the first seal and the second seal are radially directed seals.

4. The crankcase ventilation filter assembly of claim 1, wherein the stationary filter element further comprises: a lower endcap coupled with a lower end of the second filter media, the lower endcap comprising: a base interfacing with the second filter media;an inner ridge extending a first distance from the base toward an upper end of the second filter media; and an outer ridge extending a second distance from the base toward the upper end of the second filter media; wherein the first distance is less than the second distance.

5. The crankcase ventilation filter assembly of claim 4, wherein the outer ridge defines a lower endcap radially directed recess, and further comprising a sealing member positioned within the lower endcap radially directed recess, the sealing member forming a radially directed seal with the housing.

6. The crankcase ventilation filter assembly of claim 4, wherein the base, the inner ridge, and the outer ridge cooperate to define a receptacle configured to receive separated liquid, and wherein the stationary filter element further comprises a stationary drain through which the separated liquid flows from the receptacle.

7. The crankcase ventilation filter assembly of claim 6, wherein the housing defines a housing receptacle below at least one of the rotating filter element and the stationary filter element, the housing receptacle in separated liquid-receiving communication with the stationary filter element via the stationary drain.

8. The crankcase ventilation filter assembly of claim 7, wherein the housing further comprising a housing drain in separated liquid-receiving communication with the housing receptable.

9. The crankcase ventilation filter assembly of claim 8, wherein the rotating filter element defines a rotating filter element exit point, and wherein the housing receptacle is in separated liquid-receiving communication with the rotating filter element via the rotating filter element exit point.

10. The crankcase ventilation filter assembly of claim 9, wherein the rotating filter element includes an outer circumferential wall positioned radially outside of the first filter media, and wherein the rotating filter element exit point is defined between the first filter media and a lower end of the outer circumferential wall.

11. The crankcase ventilation filter assembly of claim 1, further comprising a barrier positioned at least partially between the first filter media and the second filter media, the barrier preventing liquid separated by the rotating filter element from entering the stationary filter element.

12. The crankcase ventilation filter assembly of claim 11, wherein the stationary filter element further comprises: a lower endcap coupled with the second filter media, the lower endcap comprising an inner ridge, an end of the barrier positioned below a top edge of the inner ridge.

13. The crankcase ventilation filter assembly of any of claims 1-10, wherein: the housing comprises an outlet through which filtered fluid exits the crankcase ventilation filter assembly; and the second filter media extends across the outlet.

14. The crankcase ventilation filter assembly of claim 1, wherein the rotating filter element further comprises: an outer circumferential wall positioned radially outside of the first filter media; and a drain lip extending radially inwardly and axially upwardly from an upper end of the outer circumferential wall, the drain lip retaining separated liquid therebelow and mitigating an outflow of the separated liquid from the first filter media to the second filter media.

15. A filter assembly, comprising:a housing; a rotating filter element positioned at least partially within the housing, the rotating filter element comprising: a first filter media configured to rotate within the housing and structured for axial flow of a fluid through the first filter media, and an outer circumferential wall positioned radially outward of the first filter media, a lower end of the outer circumferential wall at least partially defining a rotating filter element exit point through which separated liquid drains from the rotating filter element; and a stationary filter element positioned at least partially within the housing, the stationary filter element comprising: a second filter media positioned radially outward from the first filter media and the outer circumferential wall, the second filter media and structured for inside-out radial flow of the fluid through the second filter media after passing through the first filter media, and a lower endcap coupled to a lower portion of the second filter media, the lower endcap including an inner ridge, the inner ridge at least partially defining a stationary filter element exit point through which separated liquid drains from the stationary filter element, wherein a lower end of the outer circumferential wall is positioned axially lower than an upper edge of the inner ridge, thereby inhibiting separated liquid from flowing from the rotating filter element exit point into the stationary filter element.

16. The filter assembly of claim 15, wherein the housing defines at least one housing receptacle positioned axially below at least one of the rotating filter element and the stationary filter element, each of the at least one housing receptacle in separated liquidreceiving communication with at least one of the rotating filter element and the stationary filter element.

17. The filter assembly of claim 16, wherein the housing further comprising at least one housing drain, each of the at least one housing drain in separated liquid-receiving communication with at least one of the at least one housing receptable.

18. The filter assembly of any of claims 15-17, further comprising a drain lip extending radially inwardly and axially upwardly from an upper end of the outer circumferential wall, the drain lip retaining separated liquid therebelow and mitigating an outflow of the separated liquid from the first filter media to the second filter media.

19. The filter assembly of any of claims 15-17, wherein the lower endcap defines a lower endcap radially directed recess, and further comprising a sealing member positioned within the lower endcap radially directed recess, the sealing member forming a radially directed seal with the housing.

20. The filter assembly of any of claims claim 15-17, wherein the lower endcap further comprises a base interfacing with the second filter media and an outer ridge extending from the base toward the upper end of the second filter media, and wherein the base, the inner ridge, and the outer ridge cooperate to define a receptacle configured to receive separated liquid from the second filter media.

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