Air filtration device for internal combustion engine

Abstract

Filtration method and device for filtering solid contaminants from a stream of a flowing fluid such as internal combustion engine intake air. An imperforate housing has a tubular inlet exiting at its downstream end into a conically divergent first wall section terminating in a maximum diameter apex. A convergent second wall section terminates at a housing outlet opening of greater diameter than that of the housing inlet. A perforate filter element disposed within the housing conical portions has an exterior configuration generally complimental to the housing interior, and thus has a first generally conical divergent section, and a second generally conical downstream section convergent from a maximum diameter apex of the filter element and defining the filter device outlet. The housing and filter element define therebetween first and second frustoconical annular fluid flow chambers of successively diminishing cross-sectional radial thickness in the direction of downstream fluid flow.

1. A method for filtering solid contaminants from a stream of flowing fluid comprising the steps of:
 (1) providing a housing having a tubular inlet exiting at its downstream end into a conically divergent first imperforate housing conical wall section having a first taper angle of divergence in a downstream direction and terminating in a maximum diameter apex and then continuing in a conically convergent second imperforate housing conical wall section having a second taper angle of convergence and having an outlet opening of greater diameter than the diameter of the inlet opening of the first wall section at the tubular inlet,  
 (2) providing a fluid-pervious filter element disposed within an interior chamber of the housing defined by said conical wall sections of the housing and having an exterior configuration generally complimental  complemental to that of the interior chamber of the housing, said filter element comprising a first generally conical wall section divergent at a third taper angle of divergence juxtaposed to said housing first wall section and a second generally conical wall section convergent at a fourth taper angle of convergence juxtaposed to said housing second wall and extending axially downstream from a maximum diameter apex of the filter to an outlet of said filter element, and  
 (3) orienting the housing and filter element relative to one another and to the flowing fluid stream to thereby cause the fluid to enter the housing inlet and then to flow axially along and between the filter element and housing and then radially inwardly through the filter element and then exit via the filter element outlet whereby solid contaminants are entrained on the exterior surface of the filter element.  
 
     
     
       2. The method of  claim 1  wherein said third taper angle divergence of said filter element is slightly greater than said first taper angle of divergence of the housing to thereby define an annular space therebetween of frustoconical contour having a cross-sectional area that diminishes in the downstream direction of fluid flow. 
     
     
       3. The method of  claim 2  wherein said second taper angle of convergence of said housing is greater than said fourth taper angle of convergence of said filter element. 
     
     
       4. The method of  claim 3  wherein said fourth taper angle of convergence of the second wall section of said filter element is greater than the third taper angle of divergence of said first wall section of said filter element. 
     
     
       5. The method of  claim 4  wherein said second taper angle of convergence of the convergent downstream second wall section of said housing is greater than said first taper angle of divergence of the upstream divergent first wall section of said housing. 
     
     
       6. The method of  claim 5  wherein said housing is constructed of flexible rubbery material and is molded as a one-piece unit. 
     
     
       7. The method of  claim 5  wherein said housing comprises a two-piece unit comprising half sections that mate together at mounting flanges along the side edges of each of the half sections, said housing being made of a plastic material having at least a semi-rigid characteristic sufficient to withstand substantial pressure differences in operation between that of the interior fluid flow stream and that of the exterior ambient air. 
     
     
       8. The method of  claim 1  wherein the filter element is corrugated to provide axially extending radial corrugations generally uniformly around the entire circumference of the filter element and extending substantially for the entire axial length thereof. 
     
     
       9. The method of  claim 8  wherein said filter element is made from a layout on a flat sheet blank that has a maximum radius arc at the downstream peripheral edge and a minimum radius arc at the upstream peripheral edge that when unrolled, is similar to an unrolled tapered megaphone wall, and wherein the flat layout blank is then formed through cooperative meshing tapered forming dies that are suitably corrugated with a tighter pattern on the pointed end and a wider pattern on the exit end, such that, when the sheet is rolled between these forming dies, the blank is progressively curved until the leading side edge is brought into registry with the trailing side edge to provide a generally conical shape in the overall form, and then these two side edges are suitably joined or seamed together. 
     
     
       10. The method of  claim 9  wherein the corrugations are V-shaped with rounded root and peak spices. 
     
     
       11. The method of  claim 10  wherein the forming dies are shaped to form a radially extending flange portion of filter as an integral downstream portion of the roll form. 
     
     
       12. The method of  claim 11  wherein the forming dies are suitably shaped to provide a finished bulbous configuration of the filter element. 
     
     
       13. The method of  claim 1  wherein the exterior surface of the filter element and the interior surface of the housing define therebetween an annular fluid flow chamber surrounding the filter element, and wherein the volume of said annular chamber is on the order of 15 to 20% greater than the volume defined within the interior surface of the filter element. 
     
     
       14. The method of  claim 13  wherein the volume of said annular chamber is approximately 16 to 18% greater than the volume of the interior of the filter element. 
     
     
       15. A method for filtering solid contaminants from a stream of flowing fluid comprising the steps of:
 (1) providing a housing having a tubular inlet exiting at its downstream end into an imperforate housing wall having an overall generally divergent shape in a downstream direction and having an outlet opening of greater diameter than that of an inlet opening at the tubular inlet,  
 (2) providing a perforate filter element disposed within an interior chamber defined by the interior configuration of the housing wall and having an exterior configuration generally complemental to that of the interior of the housing wall such that said filter element has an overall generally divergent shape in the downstream direction, the exterior configuration of said filter element and the interior configuration of said housing wall defining therebetween a fluid flow chamber surrounding said filter element having a volume on the order of about 15 to about 20% greater than the interior volume of said filter element, and  
 (3) orienting the housing and filter element relative to one another and to the flowing fluid stream to thereby cause the fluid to flow axially along and between the filter element and housing and then radially inwardly through the filter element and then exit via an outlet of said filter element outlet whereby solid contaminants are entrained on the exterior surface of the filter element.  
 
     
     
       16. The method of  claim 15  wherein said filter element divergent shape has a divergence angle that is slightly greater than that of the divergent shape of said housing to thereby define therebetween and in said fluid flow chamber a fluid flow space surrounding said divergent shape of said filter and having a radial cross-sectional area that diminishes in the direction of fluid flow downstream. 
     
     
       17. The method of  claim 15  wherein said filter element and said housing both have a bulbous cross-sectional shape disposed more closely adjacent their respective downstream outlet ends than to their upstream ends so as to define in the downstream flow direction from an  each having a respective apex of the bulbous section  disposed more closely adjacent their respective downstream outlet ends than to their upstream ends and spaced from the downstream outlet ends so as to define in the downstream flow direction a convergent shape. 
     
     
       18. The method of  claim 15  wherein the fluid flow chamber is blocked at its downstream end so that the only exit for the fluid flowing into the fluid flow chamber is by penetrating through and into the filter element and thence via the outlet of the filter element. 
     
     
       19. The method of  claim 18  wherein the housing tubular inlet has an imperforate tubular wall inlet section upstream of the upstream end of the filter element within the housing adapted to telescopically receive the outlet of an associated fluid feed duct for feeding fluid from a fluid intake source into the housing of the filter element. 
     
     
       20. A filtration device for filtering solid contaminants from a stream of flowing fluid comprising a housing having a tubular inlet exiting at its downstream end into a conically divergent first imperforate housing conical wall section having a first taper angle of divergence in a downstream direction and terminating in a maximum diameter apex and then continuing in a conically convergent second imperforate housing conical wall section having a second taper angle of convergence and having an outlet opening of greater diameter than the diameter of the inlet opening of the first wall section at the tubular inlet, and a fluid-pervious filter element disposed within the  an interior chamber defined by said conical wall sections of the housing and having an exterior configuration generally complimental  complemental to that of the interior conical wall sections of the housing, said filter element comprising a first generally conical wall section divergent at a third taper angle of divergence and being juxtaposed to said housing first wall section and a second generally conical wall section convergent at a fourth taper angle of convergence and being juxtaposed to said housing second wall section and extending axially downstream from a maximum diameter apex of said filter element to an outlet of said filter element. 
     
     
       21. The filtration device of  claim 20  wherein said third taper angle of divergence of said filter element is slightly greater than said first taper angle of divergence of the housing to thereby define an annular space therebetween of frustoconical contour having a cross-sectional area wherein the difference between the I.D. and O.D. thereof diminishing in the direction of fluid flow downstream. 
     
     
       22. The filtration device of  claim 21  wherein said second taper angle of convergence of said housing is greater than said fourth taper angle of convergence of said filter element. 
     
     
       23. The filtration device of  claim 22  wherein said fourth taper angle of convergence of the downstream second wall section of said filter element is greater than the third taper angle of divergence of said first wall section of said filter element. 
     
     
       24. The filtration device set forth in  claim 23  wherein said second taper angle of convergence of the convergent downstream second wall section of said housing is greater than said first taper angle of divergence of the upstream divergent first wall section of said housing. 
     
     
       25. The filtration device of  claim 24  wherein said housing is constructed of flexible rubbery material and is molded as a one-piece unit. 
     
     
       26. The filtration device of  claim 24  wherein said housing comprises a two-piece unit comprising half sections that mate together at mounting flanges along the side edges of each of the half sections, said housing being made of a plastic material having at least a semi-rigid characteristic sufficient to withstand substantial pressure differences in operation between that of the interior fluid flow stream and that of the exterior ambient air. 
     
     
       27. The filtration device of  claim 20  wherein the filter element is corrugated to provide axially extending radial corrugations generally uniformly around the entire circumference of the filter element and extending substantially for the entire axial length thereof. 
     
     
       28. The filtration device of  claim 20  wherein the exterior surface of the filter element and the interior surface of the housing define therebetween an annular fluid flow chamber surrounding the filter element, and wherein the volume of said annular chamber is on the order of 15 to 20% greater than the volume defined within the interior surface of the filter element. 
     
     
       29. The filtration device of  claim 28  wherein the volume of said annular chamber is approximately 16 to 18% greater than the volume of the interior of the filter element. 
     
     
       30. A filtration device for filtering solid contaminants from a stream of flowing fluid comprising a housing having a tubular inlet exiting at its downstream end into an imperforate housing wall having an overall generally divergent shape in a downstream direction and having an outlet opening of greater inside diameter than that of an inlet opening at the tubular inlet, and a perforate filter element disposed within an interior chamber defined by the interior configuration of the housing wall and having an exterior configuration generally complemental to that of the interior configuration of the housing wall such that said filter element has an overall generally divergent shape in the downstream direction, the exterior outside diameter (O.D.) of said filter element and the interior inside diameter (I.D.) of said housing defining therebetween an annular air flow chamber surrounding said filter element having a volume on the order of about 15 to about 20% greater than the interior volume of said filter element. 
     
     
       31. The filtration device of  claim 30  wherein the divergence angle of said filter element is slightly greater than that of said generally divergent shape of said housing wall to thereby define therebetween and in said annular flow chamber a fluid flow space surrounding said filter and having a radial cross-sectional area wherein the difference between said I.D. and O.D. thereof diminishes in the direction of fluid flow downstream. 
     
     
       32. The filtration device of  claim 30  wherein said filter element and said housing both have a bulbous cross-sectional shape disposed more closely adjacent their respective downstream outlet ends than to their upstream ends so as to define from an  each having a respective apex of the bulbous section  disposed more closely adjacent their respective downstream outlet ends than to their upstream ends and spaced from the downstream outlet ends so as to define a convergent shape in the downstream flow direction. 
     
     
       33. The filtration device of  claim 30  wherein the annular fluid flow chamber is blocked at its downstream end so that the only exit for the fluid flowing into the fluid flow chamber is by penetrating through and into the filter element and thence via the outlet of the filter element. 
     
     
       34. The filtration device of  claim 33  wherein said housing tubular inlet has an imperforate tubular wall inlet section upstream of the upstream end of the filter element within the housing adapted to telescopically receive the outlet of an associated fluid feed duct for feeding fluid from a fluid intake source into the housing of the filter element. 
     
     
       35. The filtration device of  claim 34  wherein said tubular wall inlet section of said housing tubular inlet has a mass fluid flow sensor mounted therein. 
     
     
       36. The filtration device of  claim 30  wherein said housing is constructed of flexible rubbery material and is molded as a one-piece unit. 
     
     
       37. The filtration device of  claim 30  wherein said housing comprises a two-piece unit comprising half sections that mate together at mounting flanges along the side of edges of each of the half sections, said housing being made of a plastic material having at least a semi-rigid characteristic sufficient to withstand in operation substantial pressure differences between that of the interior fluid flow stream and that of the exterior ambient air. 
     
     
       38. The filtration device of  claim 30  wherein the filter element is corrugated to provide axially extending radial corrugations generally uniformly around the entire circumference of the filter element and extending substantially for the entire axial length thereof. 
     
     
       39. A filtration device for filtering solid contaminants from a stream of flowing fluid comprising a housing having a first fluid flow opening with the housing having an overall divergent shape from the first fluid flow opening toward a second fluid flow opening of greater inside diameter than the first fluid flow opening, and a perforate filter element disposed within an interior chamber defined by an interior configuration of the housing and having an exterior configuration generally complemental to that of the interior configuration of the housing such that said filter element has an overall generally divergent shape toward the second fluid flow opening, said filter element having an exterior outside dimension and said housing having an interior inside dimension defining therebetween a fluid flow chamber surrounding said filter element and having a cross- sectional area wherein the difference between said interior inside dimension and said exterior outside dimension diminishes in the direction from said first fluid flow opening to said second fluid flow opening.   
     
     
       40. The filter device of  claim 39  wherein said filter element and said housing both have a bulbous cross- sectional shape each having a respective apex disposed more closely adjacent the respective second fluid flow opening than to the first fluid flow opening and spaced from the respective second fluid flow opening so as to define a convergent shape from the apex to the second fluid flow opening.   
     
     
       41. The filter device of  claim 39  wherein the fluid flow chamber is closed in proximity to the second fluid flow opening so that the only path for fluid flowing through the fluid flow chamber is by penetrating through the filter element between the first and second fluid flow openings of said housing. 
     
     
       42. A filtration device for filtering solid contaminants from a stream of flowing fluid comprising a housing having a tubular first fluid flow opening exiting at one axial end into a conically divergent first imperforate housing conical wall section having a first taper angle of divergence in an axial direction and terminating in a maximum diameter apex and then continuing in a conically convergent second imperforate housing conical wall section having a second taper angle of convergence and having an axial opposite second fluid flow opening of greater diameter than the diameter of the first fluid flow opening of the first wall section and a fluid- pervious filter element disposed within an interior chamber defined by said conical wall sections of the housing and having an exterior configuration generally complemental to that of the conical wall sections of the housing, said filter element comprising a first generally conical wall section divergent at a third taper angle of divergence and being juxtaposed to said housing first wall section and a second generally conical wall section convergent at a fourth taper angle of convergence and being juxtaposed to said housing second wall section and extending axially from a maximum diameter apex of said filter element to a fluid flow opening of said filter element.   
     
     
       43. The filter device of  claim 42  wherein the fluid flow chamber is closed in proximity to the second fluid flow opening so that the only path for fluid flowing through the fluid flow chamber is by penetrating through the filter element between the first and second fluid flow openings of said housing. 
     
     
       44. A method for filtering solid contaminants from a stream of flowing fluid comprising the steps of:
 (   1   )  providing a housing having a first fluid flow opening exiting at one end into an imperforate housing wall having an overall generally divergent shape toward a second fluid flow opening of greater diameter than that of an first fluid flow opening,      (   2   )  providing a perforate filter element disposed within an interior chamber defined by the interior configuration of the housing wall and having an exterior configuration generally complemental to that of the interior configuration of the housing wall such that said filter element has an overall generally divergent shape toward the second fluid flow opening, the exterior configuration of said filter element and the interior configuration of said housing wall defining therebetween a fluid flow chamber surrounding said filter element having a radial cross - sectional area that diminishes in the direction of said second fluid flow opening, and      (   3   )  orienting the housing and filter element relative to one another and to the flowing fluid stream to thereby cause the fluid to flow between the first and second fluid flow openings, axially along and between the filter element and housing, and radially through the filter element whereby solid contaminants are entrained on the filter element.     
     
     
       45. The method of  claim 44  wherein the fluid flow chamber is blocked near the second fluid flow opening and the only path for the fluid flowing through the fluid flow chamber is by penetrating through the filter element between the first and second air flow openings.