Exhaust system for a rotary crankcase ventilation system

Abstract

The crankcase ventilation system includes a housing with an inner wall. A coalescing filter element is disposed within the housing and is rotatable within the housing about an axis extending in an axial direction. The coalescing filter element includes an inner periphery defining a hollow interior and an outer periphery defining an exterior. The exterior faces the inner wall. A tangential discharge portion is disposed on the inner wall, and a lower discharge portion is disposed on the inner wall, axially below the tangential discharge portion.

Description

[0001] Cross-references to related applications This PCT application claims the benefit and priority of U.S. Provisional Application No. 63 / 569,792, filed March 26, 2024, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0002] This disclosure generally relates to a rotating crankcase ventilation system.

[0003] background During the operation of an internal combustion engine, some combustion gases can flow out of the combustion cylinders and into the engine's crankcase. These gases are commonly referred to as "blowby gases." Blowby gases consist of a mixture of aerosols, oil, and air. If released directly into the environment, the aerosols contained in the blowby gases can be harmful. Therefore, blowby gases are typically guided out of the crankcase via a crankcase ventilation system. The crankcase ventilation system allows the blowby gases to pass through a coalescer (i.e., a coalescing filter element) to remove most of the aerosols and oil contained in the blowby gases. The filtered blowby gases ("clean" gases) are then either released into the environment (in the case of an open crankcase ventilation system) or guided back to the internal combustion engine's air intake for further combustion (in the case of a closed crankcase ventilation system).

[0004] Some crankcase ventilation systems utilize rotary crankcase ventilation filter elements, such as rotary coalescer elements, which improve the filtration efficiency of the crankcase ventilation system by rotating the coalescer element during filtration. In rotary coalescer elements, contaminants (e.g., leaked gas suspensions and transported oil droplets) are separated at least partially by centrifugal separation technology.

[0005] Overview One embodiment of this disclosure relates to a crankcase ventilation system including a housing with an inner wall. A coalescing filter element is disposed within the housing and is rotatable within the housing about an axis extending in an axial direction. The coalescing filter element includes an inner periphery defining a hollow interior and an outer periphery defining an exterior. The exterior faces the inner wall. A tangential drain is disposed on the inner wall, and a lower drain is disposed on the inner wall, axially below the tangential drain.

[0006] One embodiment of this disclosure relates to a housing of a crankcase ventilation system, the housing including an inner wall defining a cavity configured to receive a coalescing filter element. The housing includes a tangential discharge portion extending through the inner wall. The tangential discharge portion is positioned at a first height along the inner wall. The housing includes a lower discharge portion extending through the inner wall. The lower discharge portion is positioned at a second height along the inner wall. The first height is axially higher than the second height.

[0007] These and other features, together with the organization and manner of their operation, will become apparent from the following detailed description taken in conjunction with the accompanying drawings, in which similar elements have similar numbers in all the several drawings described below. Brief description of the attached diagram The above and other features of this disclosure will become more fully apparent from the following description and the appended claims, taken in conjunction with the accompanying drawings. It should be understood that these drawings depict only a few embodiments according to this disclosure and are therefore not intended to limit its scope; the disclosure will be described with additional specificity and detail using the drawings.

[0009] Figure 1 This is a cross-sectional view of the crankcase ventilation system according to an embodiment.

[0010] Figure 2A This is a cross-sectional view of a crankcase ventilation system according to another embodiment.

[0011] Figure 2B is Figure 2A A cross-sectional view of the crankcase ventilation system.

[0012] Figure 3 yes Figure 2A A top cross-sectional view of the housing of the crankcase ventilation system; Figure 4 yes Figure 2A A top cross-sectional view of the crankcase ventilation system; Figure 5 yes Figure 2A Another cross-sectional view of the crankcase ventilation system; Figure 6 yes Figure 2A A cross-sectional view of the housing of the crankcase ventilation system; Figure 7 yes Figure 2A A perspective view of the crankcase ventilation system; and Figure 8 yes Figure 2A Another perspective view of the crankcase ventilation system, wherein the crankcase ventilation system is oriented at an angle relative to a vertical plane.

[0013] Reference to the accompanying drawings is consistent throughout the following detailed description. In the drawings, similar symbols generally identify similar parts unless the context otherwise requires. The illustrative embodiments described in the detailed description, drawings, and claims are not intended to be limiting. Other embodiments may be used, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. It will be readily understood that aspects of this disclosure, as generally described herein and illustrated in the figures, can be arranged, substituted, combined, and designed in a variety of different configurations, all of which are expressly contemplated and are part of this disclosure.

[0014] Detailed description of various embodiments The embodiments described herein generally relate to a rotary crankcase ventilation system including a discharge system for discharging oil separated from leaking gases. Specifically, the embodiments described herein relate to a crankcase ventilation system including a discharge system having a discharge port tangential to the discharge flow.

[0015] refer to Figure 1 The image shows a cross-sectional view of a rotary crankcase ventilation system 100 according to an example embodiment. The crankcase ventilation system 100 receives fluid, i.e., blow-by gas received from the crankcase of an internal combustion engine, and removes aerosols, oil, and other particles contained in the blow-by gas. The crankcase ventilation system includes a housing 110 and a coalescing filter element 120. The coalescing filter element is driven by various mechanisms (e.g., electric, mechanical, pneumatic, etc.).

[0016] The coalescing filter element 120 rotates within the housing 110 about an axis extending in the axial direction. As the coalescing filter element 120 rotates, it separates oil, aerosols, and other contaminants contained in leaked gases. In some embodiments, the coalescing filter element 120 is driven to rotate by a component mechanically coupled to the engine. In some embodiments, the coalescing filter element 120 is driven to rotate by a fluid motor. In some embodiments, the coalescing filter element 120 is driven to rotate by an electric motor. In some embodiments, the coalescing filter element 120 is driven to rotate by a component magnetically coupled to the engine.

[0017] The coalescing filter element 120 has an inner periphery defining a hollow interior and an outer periphery defining an exterior. The housing 110 has an inner wall 112 facing the outer periphery of the coalescing filter element 120. An inlet supplies leaked gas from the crankcase into the housing 110 and into the hollow interior of the coalescing filter element 120. An outlet delivers clean, separated air from the exterior of the coalescing filter element 120 out of the housing 110. A discharge section 114 located below the coalescing filter element 120 delivers separated oil from the exterior of the coalescing filter element 120 out of the housing 110.

[0018] During operation of the crankcase ventilation system 100, leaking gas enters the housing 110 through the inlet and reaches the hollow interior of the coalescing filter element 120. The leaking gas flows from the hollow interior through the coalescing filter element 120 in an inward-outward direction, i.e., radially outward from the hollow interior to the outside. Oil in the leaking gas is pushed radially outward from the inner periphery by centrifugal force and discharged from the outer periphery. The separated oil collects at the lower outer edge of the housing 110 near the coalescing filter element 120 and flows by gravity to the discharge section 114, as indicated by arrow 102. In some embodiments, discharge through the discharge section 114 may be provided by a one-way check valve. In some embodiments, the separated oil may be returned to the engine crankcase.

[0019] At certain angular locations of the crankcase ventilation system 100, such as when tilted upwards (e.g., 15 degrees, 20 degrees, 25 degrees, 30 degrees, 45 degrees, 60 degrees, 75 degrees), additional pressure may be required in the housing 110 to overcome gravity and expel the separated oil from the housing 110. As a result, carryover of the separated liquid may occur. In some embodiments, a high outlet velocity of the separated oil may be required to expel the separated oil.

[0020] Overall reference Figures 2A-8 This shows a crankcase ventilation system 200. Similar to... Figure 1 The crankcase ventilation system 100 and crankcase ventilation system 200 are configured to receive fluid, i.e., blow-by gases received from the crankcase of an internal combustion engine, and to remove aerosols, oil, and other particles contained in the blow-by gases. However, the exhaust system in crankcase ventilation system 200 differs from that in crankcase ventilation system 100 in that it utilizes non-gravity exhaust. In this way, the exhaust system in crankcase ventilation system 200 can provide continuous exhaust at varying angular positions.

[0021] Crankcase ventilation system 200 includes a housing 210 and a coalescing filter element 220 disposed within the housing 210. The coalescing filter element 220 rotates within the housing 110 about an axis 250 extending in an axial direction. The coalescing filter element 220 has an outer periphery 222 (e.g., an outer surface or external surface) and a hollow interior 224. The lower edge of the coalescing filter element 220 includes a plurality of discharge channels 226. At least some of the oil removed from the leaked gas can exit the coalescing filter element 220 via the discharge channels 226. In some embodiments, the coalescing filter element 220 is functionally and / or structurally similar to any coalescing filter element described herein.

[0022] The housing 210 has an inner wall 212 facing the outer periphery 222 of the coalescing filter element 220. The inner wall 212 defines a cavity configured to receive the coalescing filter element 220. The housing 210 has an inlet 228. The inlet 228 supplies leaked gas from the crankcase into the housing 210 and into the hollow interior 224 of the coalescing filter element 220. Figure 2A In the illustrated embodiment, inlet 228 may be oriented at an angle. For example, when crankcase ventilation system 200 is in a vertical position and axis 250 extends vertically (e.g., perpendicular to a horizontal surface or floor), inlet 228 is oriented at an angle relative to the horizontal surface or floor. For example, inlet 228 may not be parallel to the horizontal surface or floor, or perpendicular to axis 250. Housing 210 has outlet 230. Outlet 230 delivers clean, separated air from the outside of coalescing filter element 220 out of housing 210. Leaking gas flows from hollow interior 224 through coalescing filter element 220 in an inward-outward direction, i.e., radially outward from hollow interior 224 to outer periphery 222. Oil in the leaking gas is propelled radially outward from hollow interior 224 by centrifugal force and discharged from outer periphery 222.

[0023] The housing 210 has a bottom surface 232. Separated oil is collected at or on the bottom surface 232 of the housing 210. The bottom surface 232 or a portion thereof is located near the lower edge of the coalescing filter element 220. The bottom surface 232 extends radially inward from the inner wall 212 of the housing 210.

[0024] The bottom surface 232 may have multiple portions disposed at different heights within the housing 210. For example, the bottom surface 232 may have a first portion 234. The first portion 234 extends radially inward from the inner wall 212. The first portion 234 has a first end 235 and a second end 236. In some embodiments, the first end 235 and the second end 236 may be disposed at the same axial height. For example, the first portion 234 may have a flat planar surface extending along a horizontal plane perpendicular to the axial direction of the housing 210. In some embodiments, the first end 235 and the second end 236 may be disposed at different axial heights. For example, the first end 235 may be positioned axially higher than the second end 236, such that the first portion 234 has a spirally downward slope.

[0025] The bottom surface 232 may have a second portion 237. The second portion 237 may be located at a lower position along the axial direction than the first portion 234. In some embodiments, the second portion 237 may extend between a first end 235 and a second end 236 of the first portion 234.

[0026] In some embodiments, the bottom surface 232 may have a third portion 238. The second portion 237 may be disposed at a position lower in the axial direction than the first portion 234, and the third portion 238 may be disposed at a position lower in the axial direction than the second portion 237. The second portion 237 and the third portion 238 may be disposed between the first end 235 and the second end 236 of the first portion 234.

[0027] In some embodiments, the housing 210 includes a protrusion 240. The protrusion 240 extends radially inward from the inner wall 212. The protrusion 240 is positioned at a position higher in the axial direction than the bottom surface 232. The protrusion 240 is configured to guide separated oil into a tangential discharge portion 216. For example, the surface of the protrusion 240 may be parallel to the tangential discharge portion 216, allowing oil to slide along the protrusion 240 and directly into the tangential discharge portion 216.

[0028] The crankcase ventilation system 200 includes a discharge system 213. Separated oil exits the housing 210 via the discharge system 213. The discharge system 213 includes a lower discharge section 214 and a tangential discharge section 216. The discharge system 213 in the crankcase ventilation system 200 allows the separated oil to flow in two separate flow paths. In a first flow path 217, the separated oil exits the housing 210 via the tangential discharge section 216. In a second flow path 218, the separated oil exits the housing 210 via the lower discharge section 214.

[0029] In some embodiments, the lower discharge portion 214 and the tangential discharge portion 216 are aligned along an axial plane. In some embodiments, the lower discharge portion 214 and the tangential discharge portion 216 are axially offset. In some embodiments, the lower discharge portion 214 and the tangential discharge portion 216 are substantially parallel to each other. In some embodiments, the lower discharge portion 214 and the tangential discharge portion 216 are angularly offset from each other (e.g., vertically, horizontally, or both). In some embodiments, a conduit may be fluidly connected to the lower discharge portion 214 and the tangential discharge portion 216.

[0030] The tangential discharge portion 216 is located on the inner wall 212 at an axially intermediate position above the lower discharge portion 214. For example, the tangential discharge portion 216 is positioned at a first height along the inner wall 212. The lower discharge portion 214 is disposed at a second height along the inner wall 212. The first height is axially higher than the second height. In some embodiments, the tangential discharge portion 216 is located on the inner wall 212, near the lower outer edge of the coalescing filter element 220.

[0031] The tangential discharge portion 216 defines an orifice extending through the inner wall 212 of the housing 210. The tangential discharge portion 216 defines a central axis 219. The tangential discharge portion 216 is oriented relative to the inner wall 212 at a discharge angle 255. For example, as... Figure 3 As shown, the tangential discharge portion 216 extends through the inner wall 212 at point 260. Point 260 is defined at the intersection of the central axis 219 and the inner wall 212. At point 260, the inner wall 212 extends in a first direction 265. The first direction 265 is tangential to the inner wall 212 at this point (e.g., the line in the first direction 265 intersects the curved inner wall 212 only at point 260). The tangential discharge portion 216 extends from point 260 in a second direction 275. The angle between the first direction 265 and the second direction 270 is the discharge angle 255. The tangential discharge portion 216 is oriented to produce a small discharge angle 255. For example, the discharge angle 255 is less than 45 degrees. Figure 3 As shown, the discharge angle 255 can be less than 30 degrees. The separated oil flows more easily from the inner wall 212 into the tangential discharge section 216, which has a smaller discharge angle 255.

[0032] The tangential discharge portion 216 is axially aligned with the tangential velocity direction of a portion of the oil in the coalescing filter element 220. For example, the discharge passage 226 of the coalescing filter element 220 can be axially aligned with the central axis 219. This alignment of the discharge passage 226 with the central axis 219 of the tangential discharge portion 216 allows oil exiting the coalescing filter element 220 via the discharge passage 226 to flow out of the housing 210 via the tangential discharge portion 216. The arrangement of the tangential discharge portion 216 utilizes the high swirling velocity at the inner wall 212 of the housing to aid in the discharge of separated oil. Therefore, when the crankcase ventilation system 200 is oriented in various locations where gravity drainage may be insufficient, the tangential discharge portion 216 allows the crankcase ventilation system 200 to discharge separated oil. The placement of the tangential discharge portion 216 further allows for a more compact crankcase ventilation system design.

[0033] A tangential discharge portion 216 is axially disposed above the bottom surface 232. A lower discharge portion 214 is disposed at a position axially lower than at least a portion of the bottom surface 232. For example, in Figure 3 In the illustrated embodiment, the bottom surface 232 includes a first portion 234 and a second portion 237. The second portion is positioned at a lower position axially than the first portion. The tangential discharge portion may be positioned at a higher position axially than the first portion, and the lower discharge portion may be positioned axially between the first and second portions.

[0034] like Figure 3 As shown, the bottom surface 232 includes a third portion 238. The second portion 237 is located at a lower position axially than the first portion 234, and the third portion 238 is located at a lower position axially than the second portion 237. The lower discharge portion 214 extends through the inner wall 212 at an axial position between the second portion 237 and the third portion 238.

[0035] like Figure 3 As shown, the tangential discharge portion 216 is positioned adjacent to the protrusion 240. For example, the protrusion 240 and the tangential discharge portion 216 are positioned at the same axial height. The protrusion 240 can facilitate the movement of separated oil into the tangential discharge portion 216. The protrusion 240 is configured to change the orientation of the inner wall 212 at a point 260 where the tangential discharge portion 216 extends through the inner wall 212 to reduce the discharge angle 255.

[0036] like Figure 8 As shown, the crankcase ventilation system 200 includes at least one check valve 221. For example, the check valve 221 may be located in or connected to the tangential discharge section 216. The check valve 221 may also be located in or connected to the lower discharge section 214. In some embodiments, discharge through the tangential discharge section 216 and / or the lower discharge section 214 can be provided via the check valve 221.

[0037] like Figures 2A-4 As shown, the tangential discharge portion 216 is an opening extending through the inner wall 212 of the housing 210. In some embodiments, the tangential discharge portion 216 includes a plurality of discharge holes.

[0038] The lower discharge portion 214 is located on the inner wall at a lower axial position than the tangential discharge portion 216. Separated oil flows to the lower discharge portion 214 by gravity. In some embodiments, the lower discharge portion 214 and the tangential discharge portion 216 are aligned along the same axial (e.g., vertical) plane. In some embodiments, the lower discharge portion 214 and the tangential discharge portion 216 may be vertically offset (e.g., extending in different axial planes). In some embodiments, the lower discharge portion 214 and the tangential discharge portion 216 are substantially parallel to each other. In some embodiments, the lower discharge portion 214 and the tangential discharge portion 216 are angularly offset to each other (e.g., vertically, horizontally, or both). In some embodiments, the lower discharge portion 214 and the tangential discharge portion 216 allow separated oil to flow within the housing 210 perpendicular to the axis extending in the axial direction.

[0039] In some embodiments, the lower discharge portion 214 is an opening in the sidewall of the housing 210. In some embodiments, the lower discharge portion 214 includes a plurality of discharge holes. In some embodiments, discharge through the lower discharge portion 214 can be provided by a check valve. In some embodiments, the lower discharge portion 214 can be omitted.

[0040] Therefore, the crankcase ventilation system 200 provides both gravity discharge and discharge assisted by a high swirling velocity. In some embodiments, when the crankcase ventilation system 200 is tilted upward, the separated oil is discharged through a tangential discharge section 216. In some embodiments, a smaller portion of the separated oil is discharged through a lower discharge section 214.

[0041] refer to Figure 8 The crankcase ventilation system 200 is shown oriented at an angle. In some embodiments, the crankcase ventilation system 200 may be oriented at an angle such that the axis 250 of the crankcase ventilation system 200 is angled relative to a vertical plane (e.g., not perpendicular to a horizontal plane). When the crankcase ventilation system 200 is oriented at an angle, the high swirling velocity of the crankcase ventilation system 200 allows oil to continue to be discharged from the crankcase ventilation system 200 via the tangential discharge portion 216.

[0042] It should be noted that the term “example” 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 imply that such embodiments must be particular or best examples).

[0043] As used herein, the term "substantially" and similar terms are intended to have a broad meaning consistent with common and accepted use by one of ordinary skill in the art to which the subject matter of this disclosure pertains. Those skilled in the art upon reviewing this disclosure will understand that these terms are intended to allow for the description of certain features described and claimed, without limiting the scope of these features to the precise numerical ranges provided. Therefore, these terms should be interpreted as indicating that non-substantial or irrelevant modifications or alterations to the described and claimed subject matter (e.g., within five percent of a given angle or other value) are considered to be within the scope of the invention as set forth in the appended claims.

[0044] As used herein, the terms “link”, “connection”, etc., refer to the direct or indirect connection between two components. Such a connection can be fixed (e.g., permanent) or movable (e.g., removable or releasable). Such a connection can be achieved by the two components, or two components and any additional intermediate components, being integrally formed into a single unit, or by the two components, or two components and any additional intermediate components, being attached to each other.

[0045] References to the location of elements herein (e.g., "top", "bottom", etc.) are used only to describe the orientation of the various elements in the accompanying drawings. It should be noted that, according to other exemplary embodiments, the orientation of different elements may differ, and such variations are intended to be covered by this disclosure.

[0046] It is important to note that the structures and arrangements of the various exemplary embodiments are merely illustrative. While only a few embodiments have been described in detail in this disclosure, those skilled in the art will readily recognize that many modifications (e.g., variations in the size, dimensions, structure, shape and proportion of various elements, values ​​of parameters, mounting arrangements, use of materials, color, orientation, etc.) are possible without substantially departing from the novel teachings and advantages of the subject matter described herein. Other substitutions, modifications, variations, and omissions may also be made in the design, operating conditions, and arrangements of the various exemplary embodiments without departing from the scope of the embodiments described herein.

[0047] While this specification contains numerous specific implementation details, these should not be construed as limiting any embodiment or the scope of the claims, but rather as descriptions of features characteristic of a particular implementation of a particular embodiment. Certain features described in the context of individual implementations may also be implemented in combination in a single implementation. Conversely, various features described in the context of a single implementation may also be implemented individually or in any suitable sub-combination in multiple implementations. Furthermore, although the foregoing features may be described as functioning in certain combinations, or even originally claimed, in some cases one or more features from a claimed combination may be removed from that combination, and the claimed combination may refer to a sub-combination or a variation of a sub-combination.

Claims

1. A crankcase ventilation system, comprising: A housing, the housing including an inner wall; A coalescing filter element disposed within the housing, the coalescing filter element being rotatable within the housing about an axis extending in an axial direction, the coalescing filter element including an inner periphery defining a hollow interior and an outer periphery defining an exterior facing the inner wall; A tangential discharge section is disposed on the inner wall of the housing; and The lower discharge section is disposed on the inner wall and is axially located below the tangential discharge section.

2. The crankcase ventilation system according to claim 1, wherein, The tangential discharge section is located near the lower edge of the coalescing filter element.

3. The crankcase ventilation system according to claim 2, wherein, The coalescing filter element includes a plurality of discharge channels disposed at the lower edge of the coalescing filter element, the plurality of discharge channels being axially aligned with the tangential discharge portion.

4. The crankcase ventilation system according to claim 1, wherein: The tangential discharge section defines a central axis, which intersects the inner wall at a point; The inner wall extends from the point in a first direction, and the tangential discharge portion extends from the point in a second direction; The first direction and the second direction define a discharge angle, which is less than 45 degrees.

5. The crankcase ventilation system according to claim 1, wherein, The tangential discharge portion is an opening that extends through the inner wall of the housing.

6. The crankcase ventilation system according to claim 1, wherein, The lower discharge section and the tangential discharge section are aligned along a single axial plane.

7. The crankcase ventilation system according to claim 1, wherein, The housing includes a bottom surface, wherein the tangential discharge portion is axially disposed above the bottom surface.

8. The crankcase ventilation system according to claim 7, wherein, The bottom surface includes a first portion and a second portion, wherein a first end and a second end of the first portion are disposed at the same height, and the second portion is disposed at a lower position along the axial direction than the first portion, and the second portion extends between the first end and the second end of the first portion.

9. The crankcase ventilation system according to claim 7, wherein, The bottom surface includes a first part and a second part, wherein a first end of the first part is located at a position higher in the axial direction than a second end of the first part, such that the first part has a spirally downward inclined portion, and the second part is located at a position lower in the axial direction than the first part.

10. The crankcase ventilation system according to claim 7, wherein, The bottom surface includes a first portion, a second portion, and a third portion, wherein the second portion is located at a lower position along the axial direction than the first portion, and the third portion is located at a lower position along the axial direction than the second portion, and the lower discharge portion extends through the inner wall at an axial position between the second portion and the third portion.

11. The crankcase ventilation system according to claim 1, wherein, The housing includes a protrusion extending radially inward from the inner wall, the protrusion being adjacent to the tangential discharge portion.

12. The crankcase ventilation system according to claim 1, further comprising: A first check valve is disposed in the tangential discharge section; and A second check valve is provided in the lower discharge section.

13. A housing for a crankcase ventilation system, the housing comprising: An inner wall defining a cavity configured to receive a coalescing filter element; A tangential discharge section extends through the inner wall and is positioned at a first height along the inner wall; and The lower discharge section extends through the inner wall and is positioned at a second height along the inner wall, the first height being axially higher than the second height.

14. The housing according to claim 13, wherein: The tangential discharge section defines a central axis, which intersects the inner wall at a point; The inner wall extends from the point in a first direction, and the tangential discharge portion extends from the point in a second direction; The first direction and the second direction define a discharge angle, which is less than 45 degrees.

15. The housing according to claim 13, wherein, The lower discharge section and the tangential discharge section are aligned along a single vertical plane.

16. The housing according to claim 13, further comprising a bottom surface, wherein the tangential discharge portion is axially disposed above the bottom surface, and the lower discharge portion is axially disposed below at least a portion of the bottom surface.

17. The housing according to claim 16, wherein, The bottom surface includes a first portion and a second portion, wherein a first end and a second end of the first portion are disposed at a first axial position, and the second portion is disposed at a second axial position below the first axial position, the second portion extending between the first end and the second end of the first portion.

18. The housing according to claim 16, wherein, The bottom surface includes a first part and a second part, the second part being axially located below the first part, wherein the tangential discharge portion is positioned at an axial position higher than the first part, and the lower discharge portion is axially positioned between the first part and the second part.

19. The housing according to claim 13, further comprising a protrusion extending radially inward from the inner wall, the protrusion being adjacent to the tangential discharge portion.

20. The housing according to claim 13, wherein, The tangential discharge section is an opening that extends through the inner wall.

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