Filter unit for the filtration of gaseous fluids, in particular air filter in internal combustion engines

1. An air filter unit for internal combustion engines, comprising:

a spirally wound filter element having opposing axial end faces, said filter element including

a support core;

a filter sheet spirally wound about said support core and having a plurality of parallel extending flow channels for filtration of air;

wherein neighboring flow channels of said parallel channels are alternatingly open or closed off at oppositely positioned end faces;

wherein said parallel flow channels that are immediately adjacent to the support core and are open at an axial outflow side are covered by an additional cover element that is connected to a component of the filter unit;

wherein said cover element completely covers said support core at its axial end face.

2. The filter unit according to claim 1 , wherein

several flow channels immediately adjoining the support core in the radial direction are covered by the cover element.

3. The filter unit according to claim 1 , wherein

all flow channels immediately adjacent to the support core are covered by the cover element at the axial outflow side of the filter element.

4. The filter unit according to claim 1 , further comprising:

a circumferentially extending frame that frames said filter element;

wherein said cover element is connected by securing ribs to said circumferentially extending frame.

5. The filter unit according to claim 4 , wherein

said securing ribs are positioned angularly relative to a center plane through said support core.

6. The filter unit according to claim 5 , wherein

said securing ribs are positioned at an angle different from 90 degrees relative to said center plane through said support core.

7. The filter unit according to claim 5 , wherein

said securing ribs are positioned at a right angle relative to said center plane through said support core.

8. The filter unit according to claim 5 , wherein

said securing ribs are aerodynamically contoured.

9. The filter unit according to claim 5 , wherein

said cover element, said securing ribs and said frame are formed as a monolithic component as a plastic injection-molded component.

10. The filter unit according to claim 5 , wherein

flow channels immediately adjoining the support core in the radial direction are covered by the cover element;

said cover element covers fluid-tightly said immediately adjoining flow channels that are open at the axial outflow side;

said cover element, said securing ribs and said frame are formed as a monolithic component as a plastic injection-molded component;

wherein said cover element is formed monolithically with said support core;

wherein said cover element is provided with an axially projecting reinforcement rib;

and

wherein in an area of the outflow side a flow-optimized extension part is placed onto the end face of the filter element.

11. The filter unit according to claim 1 , wherein

said cover element is glued onto said end face of said filter element.

12. The filter unit according to claim 11 , wherein

flow channels immediately adjoining the support core in the radial direction are covered by the cover element;

said cover element covers fluid-tightly said immediately adjoining flow channels that are open at the axial outflow side;

wherein said cover element is formed monolithically with said support core;

wherein said filter sheet is glued to said support core;

wherein said cover element is provided with an axially projecting reinforcement rib;

wherein said filter element has an oval cross-section;

and

wherein in an area of the outflow side a flow-optimized extension part is placed onto the end face of the filter element.

13. The filter unit according to claim 1 , wherein

said cover element is formed monolithically with said support core.

14. The filter unit according to claim 1 , wherein

said filter sheet is glued to said support core.

15. The filter unit according to claim 1 , wherein

said cover element is provided with an axially projecting reinforcement rib.

16. The filter unit according to claim 1 , wherein

said filter element has an oval cross-section.

17. The filter unit according to claim 1 , wherein

in an area of the outflow side a flow-optimized extension part is placed onto the end face of the filter element.

18. An intake module of an internal combustion engine with a filter unit according to claim 1 and a mass airflow sensor arranged downstream of the filter unit.

19. An air filter unit for internal combustion engines, comprising:

a spirally wound filter element having opposing axial end faces, said filter element including

a support core;

a filter sheet spirally wound about said support core and having a plurality of parallel extending flow channels for filtration of air;

wherein neighboring flow channels of said parallel channels are alternatingly open or closed off at oppositely positioned end faces;

wherein said parallel flow channels that are immediately adjacent to the support core and are open at an axial outflow side are covered by an additional cover element that is connected to a component of the filter unit;

wherein the cover element covers fluid-tightly said immediately adjacent flow channels that are open at the axial outflow side.