DEVICE FOR FILTERING THE INTAKE AIR OF INTERNAL COMBUSTION ENGINES

Abstract: A device for filtering the intake air of internal combustion engines, provided with an expansion box (110) having an opening (12), includes: a first filtering tubular element (2); an upper annular element (1) provided with an upper annular housing (8) in which the upper end of the filtering element is fixed (2); a second filtering element (3) peripherally fixed to the upper element (1); supporting means (4) provided with a lower annular housing (9), in which the lower end of the filtering element is fixed (2); a central hole (5) in flow communication with the opening (12) in correspondence of an assembling condition M; a flat flange (7) for fixing the expansion box (110).

Description: DEVICE FOR FILTERING THE INTAKE AIR OF INTERNAL COMBUSTION ENGINES TECHNICAL FIELD The present invention relates to filters for filtering the intake air of internal combustion engines. Essentially the invention refers to filters for the intake air of supercharged and aspirated internal combustion engines, particularly of the type used in the races. As known in the automotive field, the air filtering has particular importance since conditions the gasoline and air mixing and therefore the so obtained fuel mixture used in the combustion. The intake air therefore must be filtered for removing any impurities that may clog or wear and damage the inner members of the engine. The known air filters are normally flattened, cylindrical or conical shaped and they need a case or a container fixing, supporting and inserting said air filters inside the airflow. However the case has the drawback to encumber the motor compartment. Another drawback of the known filters consists in that, once assembled, they are not visible and therefore they must be disassembled to be checked. A further drawback of the known filters consists in that the filtering elements have form and dimensions preset by the characteristics of the relative container and therefore not adjustable. The known filters for the use in sporting engines, the usually called "sprint filter", have polyester filtering elements, whose ends have heavy polyurethane flanges and/or caps that are extremely expensive and further cannot withstand temperatures greater than 90° C, because of the used material. These filters are generally truncated cone shaped and they are enclosed in metallic containers shaped as almost conic or truncated -conic portions. The known filters with the paper filtering elements guarantee a good filtration, because they hold particles bigger than 10 μm, but they have the drawback of an excessive flow resistance for the airflow passing through. Another drawback of the known filters consists in the insufficient filtering surface, due to the conic shape of the filter having wide inclination angles. DISCLOSURE OF THE INVENTION The main object of the present invention is to propose a filter for the intake air of internal combustion engines that does not require a special case or container but that is assembled on the expansion box of the intake collector. A further object of the present invention is to propose a visible and checkable filter from the outside and with an easy and fast assembling and disassembling. A further object is to propose a filter with adjustable geometric features without modifying the fixing or housing means. A further object is to propose a light filter but at the same time solid, stiff and resistant to temperatures higher than 200 C°. Other object is to propose a filter with a large surface of the filtering elements and low flow resistances of the filtered air. Further object is to propose a filtering device reliable having a life for a route not less than 150.000 km, however usable with a very low maintenance and easy to dispose because principally made of a natural material. BRIEF DESCRIPTION OF THE DRAWINGS The characteristics of the invention are underlined in the following with particular reference to the attached drawings, in which: figure 1 shows a perspective view of the filter in an assembled condition in the engine; figure 2 shows an enlarged longitudinal section view of the filter of figure 1 ; - figure 3 shows a top view of the filter of figure 2; figure 4 shows a plant view of supporting means of the filter of figure 2; figure 5 shows a section view according to the plain V-V of the supporting means of the figure 4; figure 6 shows a section view of two variant of the filter of figure 1 in correspondence of the assembling condition; figure 7 shows a section view of the filter of figure 6 in correspondence of a variant of the assembling condition. BEST MODE OF CARRYING OUT THE INVENTION With reference to the figures from 1 to 7, numeral 10 indicates a filter for the intake air of internal combustion engines, numeral 100 indicates an intake collector of the air and numeral 110 indicates an expansion box of the internal combustion engine. The filter 10 includes a first filtering element 2, a second filtering element 3, a top element 1 and supporting means 4. The first filtering elements 2 are tubular shaped, for instance cylindrical or truncated-conical shaped with round or oval or elliptical cross sections, delimited by an upper and a lower end. The second filtering elements 3 are substantially flat with a circular or oval or elliptical shape. The first filtering elements 2 have angular or undulated beads in order to stiffen the structure and to increase the surface development. Both the filtering elements, first 2 and second 3, are made by interposing between two layers of metallic net, for instance made of aluminum, a plurality, for instance four, of layers of fabric or felt in natural cotton soaked with low viscosity oil, before assembling the filter 10. The upper element 1 consists in a circular or elliptical or oval flange having a "L" shaped section whose inside angle carry out an upper annular housing 8 to which the upper ends of the first filtering elements 2 and the external edge of the second filtering elements 3 are fixed. The supporting means 4 include a lower annular housing 9, circular or oval or elliptical shaped, to which the lower end of the first filtering elements 2 is fixed. Furthermore, the supporting means 4 have a central circular hole 5 and an elliptical shaped flat flange 7 with a plurality, for instance three, of external holes 6 for assembling the filter 10. It is also provided that the upper element 1 and the supporting means 4 are made in composite material with synthetic matrix strengthened with carbon fibers. Furthermore the fixing of the first filtering elements 2 to the annular housings, upper 8 and lower 9, and the fixing of the second filtering means 3 to the upper annular housing 8 is made by gluing with bi-component synthetic resins, for instance epoxidic or polyurethanic. The collector 100 substantially consists in a duct, for instance a wrinkled flexible or rigid hose, whose ends are connected and in flow communication with the supply elements of the internal combustion engine and with the expansion box 110. The expansion box 110 substantially consists in a rigid case, for instance cylindrical shaped with elliptical section or parallelepipedal shaped, having in a flat portion fixing means 13 consisting, for instance, in stud bolts corresponding to the external holes 6 of the flange 7 and nuts or wing nuts. The expansion box 110 has an opening 12 that, in assembling condition M, mates the hole 5 of the flange 4. It is further provided a gasket 14 positioned between the flange 7 and the expansion box 110 in order to guarantee the pneumatic seal. Obviously the gasket 14, for instance made of synthetic rubber, has no interference with the fixing means and with the opening 12 of air passage of the expansion box 110. The sealing gasket 14 has also the purpose to share the forces and to uniform the joining pressure between the expansion box 110 and the filter 10 and to reduce the vibrations transmitted to this latter. The operation provides that the engine intake air flows initially through the filtering elements first and second 2,3 which purifies the air from particles and dusts, having dimensions bigger than the filtering capacity of the fabric or oil soaked cotton felt, and in sequence, flows through the expansion box 110 and the collector 100 finally arriving to the supply elements of the internal combustion engine where the air and fuel are mixed. It is advantageous to underline that it is possible to mount the filter object of the present invention in external position but also in an assembling condition MM in which the filter 10 is inside to the expansion box 110 of suitable geometric features. Besides, the filter object of the present invention is suitable for fast changes and disposition variations that are valuable features in the races and the prototypes fields. There are variants, not shown, in which the flange 7 is approximately circular or polygonal shaped in order to realize the better coupling with the expansion box 110 whit respect to the characteristics of this latter. Further variants, partially shown in figures 6 and 7, refers to the shape of the second filtering element 2 that has alternatively concave or convex shape, with approximately semi -elliptical section, developed toward the inside or the outside of the filter 10, or with beads having concentric annular parallel development, or with approximately conical shape, developed toward the outside or the inside of the filter 10, having a series of radial beads starting from the cone vertex up to the base in proximity of the upper element 1. The beads have for instance triangular or undulated sections. The above-described variants do not modify the operation but increase the filtering useful surface of the filter 10 and/or strengthen this latter. The main advantage of the present invention is to provide filters that do not need a particular container but can be mounted on an expansion box of the intake collector. A further advantage consists in that the filters according to the present invention are visible and checkable from the outside and have an easy and quick assembling and disassembling, and have variable and modifiable geometric features without modifying the fixing or housing means. Another advantage is to provide single body filters lightweight but at the same time solid, stiff and resistant to temperatures even higher than 200 C°, and filters having a large surface of the filtering elements and low flow resistance of the filtered air. A further advantage consists in providing a reliable filter having a life for a route not less than 150.000 km, however usable with a very low maintenance and easy to dispose because primarily made of a natural material.

Claims: CLAIMS 1) Device for filtering the intake air of internal combustion engines provided with an expansion box (110) having an opening (12), with the filter (10) including a first filtering tubular element (2) and being characterized in that it includes: an upper annular element (1) provided with an upper annular housing (8) in which the upper end of the filtering element is fixed (2); a second filtering element (3) peripherally fixed to the upper element (1); supporting means (4) provided with a lower annular housing (9), in which the lower end of the filtering element is fixed (2), a central hole (5) in flow communication with the opening (12) in correspondence of an assembling condition M and a flat flange (7) for fixing the expansion box (110). 2) Device according to claim 1 characterized in that the upper element (1) consists in an annular "L" section flange. 3) Device according to claim 1 characterized in that the supporting means (4) and the upper element (1) are made of composite material with synthetic matrix strengthened with carbon fibers. 4) Device according to claim 1 characterized in that the flange (7) is approximately elliptical or circular or polygonal shaped. 5) Device according to claim 1 characterized in that the flange (7) has external holes (6) in which are engaged fixing means (13) of the expansion box (110) in correspondence of said assembling condition M. 6) Device according to any of the preceding claims characterized in that the second filtering element (3) is flat and approximately circular shaped. 7) Device according to any of the preceding claims characterized in that the second filtering element (3) is concave or convex with semi-elliptical section. 8) Device according to any claims from 1 to 5 characterized in that the second filtering element (3) has a series of beads fit to increase the filtering surface and the stiffness. 9) Device according to claim 8 characterized in that the beads are annular and concentric. 10) Device according to any claims from 1 to 5 characterized in that the second filtering element (3) is approximately conical shaped and has a series of beads along its generating lines. 11) Device according to any of the preceding claims characterized in that the filtering elements first (2) and second (3) consist of a plurality of cotton layers, soaked of low viscosity oil, interposed between net elements. 12) Device according to any of the preceding claims characterized in that it further includes a gasket (14) which, in the assembling conditions (M, MM) is interposed between the expansion box (110) and the flange (4) without interfering with the holes (6) and with the opening (12). 13) Device according to any of the preceding claims characterized in that the filtering elements first (2) and second (3) and the annular housings (8, 9) are mutually glued with bi- components synthetic resins. 14) Device according to any of the preceding claims characterized in that the filter (10) is external to the expansion box (110) in correspondence of the assembling condition (M). 15) Device according to any of the preceding claims characterized in that the filter (10) is almost totally contained inside the expansion box (110) in correspondence of a second assembling condition (MM).

Inventors: BERGAMI GAETANO, BERGAMI, GAETANO
Applicants: BERGAMI GAETANO, BMC S R L, BERGAMI, GAETANO, BMC S.R.L.
Application year: 2001
Main classification: F02M35
IPC codes: F02M35