Filter module comprising a filter element in a filter housing

Abstract

A filter module is provided with a filter housing provided with an inflow opening. A filter element with an annular filter medium body with an elongate cross-sectional shape is arranged inside the filter housing. A flow path is defined between the inflow opening of the filter housing and an inflow side of the filter medium body. A swirl device is arranged in the flow path and impresses a swirl onto an incoming fluid. The swirl device is a part separate from an outer wall of the filter housing. The swirl device is arranged axially upstream of the inflow side of the filter medium body. The swirl device is provided with a displacement body arranged inside the filter housing adjacent to the inflow opening. The displacement body forms a flow guiding element.

Claims

1. A filter module comprising: a filter housing elongated along and surrounding a central axis, the filter housing comprising: an inlet housing; and a filter base housing, wherein the inlet housing is configured to be attached to the filter base housing, an inflow duct having a lateral inflow opening extending through an radial outer wall of the inlet housing, the inflow duct extending into an interior of the filter housing; a filter element arranged inside the filter base housing, the filter element comprising: an annular filter medium body surrounding the central axis and having an open interior; a first end disk arranged on and closing off a first axial end of the annular filter medium body, the first end disk positioned adjacent to and axially spaced away from the lateral inflow opening; wherein an annular flow passage is formed by a radial spacing between the annular filter medium body and an inner side of a housing wall of the filter base housing; wherein the swirl device further comprises one or more guiding ribs arranged in the annular flow passage between an end face of the filter element and the inner side of the housing wall of the filter base housing; an annular displacement body arranged inside the filter base housing and positioned upstream of the filter element, the annular displacement body comprising: a radially outer circumferential wall having: an inflow continuation wall contacting against the inflow duct at the radial outer wall of the inlet housing proximate to the lateral inflow opening, the inflow continuation wall forming a wall portion of the inflow duct inside the filter housing; the radially outer circumferential wall further comprising: a first axial end arranged at and supported on the first end disk; a second axial end arrange opposite the first axial end of the displacement body and comprises an annular axial edge contour having a geometry that follows and contacts against an inner surface contour of the inlet housing, such that an interior of the annular displacement body is closed off by the first end disk and by the inner surface contour of the inlet housing; wherein the inflow duct inside the filter housing is at least partially formed by the inflow continuation wall and the radially outer circumferential wall of the annular displacement body, the inflow duct extending across the first end disk from a first radial side of the first end disk towards an opposite second radial side of the first end disk and curved to open into the annular flow passage radially surrounding the annular filter medium body at the opposite second radial side of the first end disk; wherein a cross-sectional area of the inlet duct reduces from the lateral inflow opening in a direction towards the annular flow passage, the reducing cross-sectional area accelerating air flow to swirl about the annular filter medium in the annular flow passage, forming a swirl device effecting pre-separation of contaminants in the air flow before entering the filter medium body.

2. The filter module according to claim 1, wherein the annular displacement body is curved in a direction toward the annular flow passage arranged between an end face of the filter medium body and the inner side of the housing wall of the filter housing.

3. The filter module according to claim 2, wherein the annular displacement body, the housing wall of the filter housing and the inflow continuation wall delimit together an air flow path from the inflow opening in the direction toward the annular flow passage.

4. The filter module according to claim 1, wherein the first end disk of the filter element includes fastening elements formed as axial projections, projecting axially outward from the filter element; wherein the annular displacement body includes fastening receptacles configured to receive and engage the fastening elements to fix or center the filter element relative to the annular displacement body in the filter housing.

5. The filter module according to claim 1, wherein the one or more guiding ribs are arranged at the filter element.

6. The filter module according to claim 1, wherein the one or more guiding ribs are arranged at the filter housing.

7. The filter module according to claim 1, wherein the inflow opening is spaced radially outwards away from the central longitudinal axis.

8. The filter module according to claim 1, further comprising a flow-tight separation element arranged at or adjacent to the filter medium body of the filter element, wherein the flow-tight separation element extends across a partial surface of the filter medium body at the inflow side.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages and expedient embodiments can be taken from the additional claims, the figure description, and the drawings.

(2) FIG. 1 shows in exploded illustration a filter module as air filter for an internal combustion engine with a filter element with elongate cross-sectional shape in a filter housing, with a displacement body which is arranged in the filter housing adjacent to an inflow opening.

(3) FIG. 2 shows a section lengthwise through the filter module in a first section plane.

(4) FIG. 3 shows a section lengthwise through the filter module in a further section plane.

(5) FIG. 4 is a further illustration of the air filter, partially in section.

(6) FIG. 5 shows a further embodiment of a filter module that is embodied as an air filter, with guide vanes in the flow path between an inflow opening in the filter housing and the filter element, in exploded view.

(7) FIG. 6 shows the embodiment of FIG. 5 in longitudinal section.

(8) FIG. 7 shows a filter module embodied as air filter in an illustration according to FIG. 2 in an embodiment variant.

(9) In the Figures, same components are provided with same reference characters.

DESCRIPTION OF PREFERRED EMBODIMENTS

(10) In the first embodiment according to FIGS. 1 through 4, a filter module 1 is illustrated that is embodied as an air filter in the intake manifold of an internal combustion engine for filtration of the combustion air to be supplied to the cylinders of the internal combustion engine. The filter module 1 comprises a filter element 2 that has an elongate cross-sectional shape and is arranged in a filter housing 3 with a filter base housing 4 and an upstream inlet housing 5. The filter base housing 4 accommodates the filter element 2. In the inlet housing 5 that is to be connected to the filter base housing 4, a laterally arranged inflow opening 6 which opens into an inflow duct (at 6, see FIG. 1) via which the combustion air is introduced into the filter housing 3 and guided in the direction toward the filter element 2. Relative to a central longitudinal axis 15 of the filter element 2, the inflow opening 6 is displaced laterally or radially wherein the inflow axis of the inflow opening 6 is positioned at an angle of approximately 90° relative to the central longitudinal axis 15 of the filter element 2.

(11) The filter element 2 comprises a filter medium body 7 which is embodied in an annular closed configuration and provided with an elongate cross-sectional shape. Relative to the central longitudinal axis 15, the filter medium body 7 is flowed through in radial direction from the exterior to the interior by the fluid to be filtered, the combustion air, so that the outer side of the filter medium body 7 forms the raw side or inflow side and the inner side the clean side. The filter medium body 7 is lined at its inner or clean side by a support frame 8 which is comprised of plastic material. The inwardly positioned flow space in the filter medium body 7 forms the clean space in which the purified fluid is collected and from which the purified fluid is axially discharged.

(12) At the two oppositely positioned end faces of the filter element 2, an end disk 9, 10 is arranged, respectively, wherein the first end disk 9 neighboring the inflow opening 6 is embodied in a closed configuration and the second oppositely positioned end disk 10 facing away from the inflow opening 6 is embodied in an open configuration so that the fluid can flow axially out of the inwardly positioned clean space via the open end disk 10. Adjacent to the open end disk 10 of the filter element 2, a housing-associated outlet section 11 adjoins the filter base housing 4 and comprises an outflow opening 12 (FIG. 1) via which the purified fluid is discharged from the filter module 1.

(13) The cross-sectional shape of the filter element 2 or of the filter medium body 7 is elongate wherein the longitudinal sides extend planar and parallel to each other and are connected by curved narrow sides. The extension of the longitudinal sides is at least twice as large as the distance bridged by the narrow sides, i.e., the distance between the two longitudinal sides. Across the axial length, relative to the central longitudinal axis 15, the filter element 2 and the filter medium body 7 have a non-constant cross section which in the region of the closed end disk 9 is smaller than in the oppositely positioned region with the open end disk 10 and increases continuously and uniformly from the smaller to the larger cross section.

(14) Adjacent to the housing-associated outlet section 11, the filter base housing 4 is provided with a radially expanded annular space 14 at which a discharge valve 13 is arranged. In the radially expanded annular space 14, separated dirt particles can collect which can be discharged through the discharge valve 13 from the filter housing.

(15) A displacement body 16 which is annular (see FIG. 1) is inserted in the inlet housing 5 and significantly reduces the free volume that is available in the inlet housing 5 for receiving the introduced fluid and, at the same time, forms a defined flow path for the fluid in the direction toward the filter element 2 with the filter medium body 7. The displacement body 16 is fastened in the inlet housing 5 and preferably comprises receptacles for the filter element 2 that receive the filter element 2, preferably its closed end disk 9, in a detachable way. For this purpose, at the outer circumference of the end disk 9, distributed about the circumference, a plurality of fastening elements 17 formed as projections (see FIG. 1) are arranged that have correlated therewith corresponding fastening receptacles 18 at the displacement body 16. The fastening elements 17 and receptacles 18 are to be brought into fastening engagement in order to center the displacement body 16 and the filter element 2 relative to each other.

(16) The displacement body 16 is dimensioned such that between the outer side of the displacement body 16 and the inner side of the outer housing wall of the inlet housing 5 a flow path 19 (FIG. 3) is formed for the fluid which is introduced via the inflow opening 6. The outer contour of the displacement body 16 has an annular axial edge contour (16C, see FIG. 1) having a geometry that follows and contacts against the inner contour of the inlet housing 5 such that an interior of the displacement body (16) is closed off by the first end disk (9) and by the inner contour of the inlet housing 5. Both contours are embodied in a curved configuration so that the flow path 19 is also correspondingly curved. The flow path 19 extends in the direction toward a flow passage 20 which is formed between the end face of the filter medium body 7 with the end disk 9 and the housing wall of the filter housing 3. This flow passage 20 extends all around circumferentially and enables passage of the introduced fluid to the raw or inflow side of the filter medium body 7 in the filter base housing 4. The displacement body 16 as well as the inlet housing 5 are arranged axially upstream of the filter element 2 in the flow direction.

(17) The fluid which is laterally introduced via the inflow opening 6 flows into the flow path 19 between displacement body 16 and inlet housing 5 and, due to the curvature of the flow path 19, is imparted with a swirl that leads to the separation of dirt particles. In addition, in comparison to the inflow opening 6, the flow path 19 has a reduced flow cross section so that the introduced fluid is accelerated. The increased speed of the fluid and of the dirt particles entrained therein improves the degree of separation.

(18) At the outer side of the closed end disk 9, a centrally positioned support sleeve 22 is integrally formed with which the filter element 2 can be axially supported from the exterior. For this purpose, the inlet housing 5 is provided with a recess 24 which is axially aligned with the support sleeve 22 and serves as a support for the support sleeve 22.

(19) The displacement body 16 comprises an outer contour that is smaller than the inner contour of the receiving inlet housing 5. In this way, at a plurality of sides, preferably all around at all sides, between the outer wall of the displacement body 16 and the inner side of the housing wall of the inlet housing 5 a flow path is provided which extends from the inlet opening 6 in the inlet housing 5 to the flow passage 20 in the region of the closed end disk 9 of the filter element 2. This flow path 19 has a curvature in all directions so that the inflowing fluid is imparted correspondingly with a swirl in all directions and with this swirl enters the annular circumferentially extending flow passage 20 in which the guiding ribs 21 are arranged.

(20) In the flow passage 20, a plurality of guiding ribs 21 are arranged and distributed about the circumference; they form flow vanes and further accelerate the flow in the direction toward the filter medium body 7. Stated more precisely, the initial swirl which has been generated by the displacement body 16 and the housing inner wall is absorbed and further amplified. In this way, the degree of separation can also be further improved. The guiding ribs 21 can be arranged at the filter housing 3, in particular the filter base housing 4. Conceivable is also an arrangement of the guiding ribs 21 at the filter element 2, in particular at the closed end disk 9.

(21) In FIGS. 5 and 6, a further embodiment of a filter module 1 is illustrated which forms an air filter for the intake manifold of an internal combustion engine. The basic configuration of the air filter 1 and the cross-sectional geometry of the filter element 2 correspond to that of the first embodiment. In contrast to the first embodiment, the displacement body in the inlet housing 5 is missing in FIGS. 5 and 6. Accordingly, the combustion air entering via the inlet opening 6 can expand in the complete interior in the inlet housing 5 and flow in the direction toward the flow passage 20 located between the outer circumference of the closed end disk 9 at the filter medium body 7 and the inner side of the housing wall of the filter base housing 4.

(22) In the flow passage 20, guiding ribs 21 are arranged which are embodied partially as curved guiding vanes 21 and partially have straight sections. The guiding vanes 21 form a swirl device for the combustion air flowing through. Distributed about the circumference, a plurality of such guiding vanes 21 are arranged in the flow passage 20. The guiding vanes 21 are fastened in particular at the filter element 2. In an alternative embodiment, it is also possible to fasten the guiding vanes 21 at a housing part, for example, at the filter base housing 4 or at the inlet housing 5.

(23) In FIG. 7, an embodiment variant of a filter module 1 embodied as an air filter is illustrated. The basic configuration corresponds to that of FIGS. 1 to 4.

(24) The filter module 1 according to FIG. 7 comprises a filter element 2 which is embodied hollow cylindrically or with elongate cross-sectional shape and arranged in a filter housing 3 which comprises a filter base housing 4 and an upstream inlet housing 5. The filter base housing 4 and the inlet housing 5 at which an inflow opening 6 is located are of a one-piece configuration. The filter base housing 4 accommodates the filter element 2 in its receiving space 26. The combustion air to be filtered is introduced via the laterally arranged inflow opening 6 into the filter housing 3 and guided in the direction toward the filter element 2. Relative to the central longitudinal axis 15 of the filter element 2, the inflow opening 6 is positioned laterally or radially displaced wherein the inflow axis of the inflow opening 6 is positioned at an angle of approximately 90° relative to the central longitudinal axis 15 of the filter element 2.

(25) The filter element 2 comprises a filter medium body 7 which is embodied in an annular closed embodiment and provided with an elongate cross-sectional shape. Relative to its central longitudinal axis 15, the filter medium body 7 is flowed through in radial direction from the exterior to the interior by the fluid to be filtered, the combustion air, so that the outer side of the filter medium body 7 forms the raw or inflow side and the inner side the clean side. The filter medium body 7 is lined at its inner or clean side by a support frame 8 which is comprised of plastic material. The inwardly positioned flow space in the filter medium body 7 forms the clean space in which the purified fluid is collected and from which the purified fluid is axially discharged.

(26) At both oppositely positioned end faces of the filter medium body 7, an end disk 9, 10 is arranged, respectively, wherein the first end disk 9 neighboring the inflow opening 6 is embodied in a closed configuration and the second oppositely positioned end disk 10 facing away from the inflow opening 6 is embodied in an open configuration so that the fluid can flow axially out of the inwardly positioned clean space via the open end disk 10. Adjacent to the open end disk 10 of the filter element 2, a housing-associated outlet section 11 adjoins the filter base housing 4 and comprises an outflow opening 12 via which the purified fluid is discharged from the filter module 1. The outlet section 11 is embodied separate from the filter base housing 4 but is connected to the filter base housing 4.

(27) The cross-sectional shape of the filter element 2 or of the filter medium body 7 can be embodied elongate wherein the longitudinal sides in an exemplary fashion extend planar and parallel to each other and are connected by curved narrow sides. However, a circular cross-sectional shape of the filter element 2 and of the filter medium body 7 is also possible.

(28) The filter element 2 and the filter medium body 7 have across the axial length, relative to the central longitudinal axis 15, a non-constant cross section that is smaller in the region of the closed end disk 9 than in the oppositely positioned region with the open end disk 10 and increases continuously and uniformly from the smaller to the larger cross section.

(29) Adjacent to the housing-associated outlet section 11, in the filter base housing 4 a radially expanded annular space 14 is provided which forms a dirt collecting region and at which a discharge valve 13 is arranged. In the radially expanded dirt collecting region 14 which is of an annular embodiment, the separated dirt particles can collect which can be discharged via the discharge valve 13 from the filter housing 3.

(30) The discharge valve 13 is preferably embodied as a passive valve that can be adjusted by external influences from the usually closed position into an open position in which the dirt particles can be discharged. For example, it is possible to connect the discharge valve 13 to a vacuum source, e.g., to a vacuum side of a cooling fan in a vehicle, so that the discharge valve 13 is opened at sufficiently high vacuum.

(31) The dirt collecting region 14 communicates with the receiving space 26 at the raw or inflow side of the filter medium body 7. The dirt collecting region 14 is located axially adjacent to the open end disk 10 at the outflow side of the filter element 2. Relative to the axial total length of the filter element 2, the dirt collecting region 14 extends across an axial partial length that amounts to not more than 20% of the total length of the filter element 2. The dirt collecting region 14 is radially expanded relative to the immediately adjoining housing wall of the filter base housing 4. At the axial center of the dirt collecting chamber 14, the filter base housing 4 and the outlet section 11 of the housing abut each other.

(32) In radial direction, the dirt collecting region 14 is separated by a separation element 27 from the filter medium body 7 wherein the separation element 27 is embodied as a circumferentially extending conically embodied calming wall 27 which is part of the filter housing 3. The calming wall 27 forms the radially inwardly positioned boundary wall of the dirt collecting chamber 14. The calming wall 27 extends circumferentially all around and is positioned at a minimal distance relative to the inflow side or raw side of the filter medium body 7. In axial direction, the calming wall 27 extends from an end face section of the filter housing 3, in particular of the outlet section 11, at the level of the end disk 10 past the axial extension of the dirt collecting region 14. The axial length of the calming wall 27 amounts to, for example, at least one fourth of the axial total length of the filter element 2. The calming wall 27 provides for a flow calming action in this axial section in the receiving space 26 and reduces in this section the inflow into the filter medium body 7. The dirt collecting region 14 is in flow communication with the receiving space 26.

(33) Due to the flow calming action and the larger radial extension of the dirt collecting region 14 in comparison to the immediately neighboring housing wall of the filter base housing 4, dirt particles can deposit in the dirt collecting region 14 and are subsequently discharged via the discharge valve 13.

(34) The calming wall 27 is located axially adjacent to the open end disk 10 and extends in axial direction, beginning at the open end disk 10, across a partial region of the filter medium body 7.

(35) The axially oppositely positioned side is provided with a further separation element 27a in the form of a separation film which is applied immediately onto the filter medium body 7. The separation film 27a extends, beginning at the closed end disk 9, in axial direction so that the calming wall 27 and the separation film 27a extend from oppositely positioned end faces axially in the direction toward the center of the filter medium body 7. The axial length of the calming wall 27 and of the separation film 27a is at least approximately of the same size. At the center between the two separation elements 27 and 27a, a partial section of the filter medium body 7 is provided which is free of separation elements and thus can immediately receive radially incoming flow of the raw fluid to be purified.

(36) Both separation elements 27 and 27a provide for a flow calming action of the raw fluid flowing into the inflow space at the inflow side of the filter medium body so that it is possible that coarse dirt particles deposit in the annular space 14 and can be discharged via the discharge valve 13. Despite the separation elements 27 and 27a, the raw fluid can flow into the filter medium body 7 across its entire axial length and its entire inflow side. The calming wall 27 is positioned radially at a distance to the inflow side of the filter medium body 7 so that an annular space is formed between the calming wall 27 and the inflow side of the filter medium body into which the raw fluid can flow.

(37) The filter medium body 7 is of a folded configuration wherein the longitudinal extension of the folds extends parallel to the longitudinal axis 15 of the filter element. In the region of the calming film 27a that is applied immediately onto the filter medium body 7 and, for example, is welded or glued to the filter medium body 7, the raw fluid can flow along the folds of the filter medium body 7, beginning at the partial section of the filter medium body without separation element, axially into the partial region which is covered by the separation film 27a. In this way, the filter medium body 7 is available for filtration of the raw fluid even in the region of the separation film 27a.