METALLIC HOLLOW VALVE FOR AN INTERNAL COMBUSTION ENGINE OF A UTILITY MOTOR VEHICLE

Abstract

A metallic hollow valve for an internal combustion engine of a utility vehicle may include a tubular valve stem and a valve head merging into the valve stem. The valve head may have an outer diameter that is enlarged compared to the valve stem. The valve stem and the valve head may together delimit a hollow space. The valve stem may have an outer diameter of more than 7 mm, for example between 8 mm and 11 mm. The valve stem may have an inner diameter of at least 4.5 mm, for example between 5 mm and 7 mm.

Claims

1. A metallic hollow valve for an internal combustion engine of a utility vehicle, comprising: a tubular valve stem and a valve head merging into the valve stem, the valve head having an outer diameter that is enlarged compared to the valve stem; the valve stem and the valve head together delimiting a hollow space; wherein the valve stem has an outer diameter of more than 7 mm; and wherein the valve stem has an inner diameter of at least 4.5 mm.

2. The metallic hollow valve according to claim 1, wherein the valve head includes a head base facing away from the valve stem, and wherein the head base has a base thickness between 2 mm and 5 mm.

3. The metallic hollow valve according to claim 1, wherein the valve stem has a wall thickness between 1.5 mm and 5 mm.

4. The metallic hollow valve according to claim 1, further comprising a valve neck arranged between valve stem and valve head, wherein the valve neck has a wall thickness between 1.5 mm and 5 mm.

5. The metallic hollow valve according to claim 1, wherein the valve head is at least one of forged and electrochemically machined.

6. The metallic hollow valve according to claim 1, wherein the hollow space is at least partly filled with a fluid.

7. An internal combustion engine for a utility vehicle, comprising: at least one cylinder including a combustion chamber having an air inlet and an exhaust outlet; a valve drive including a metallic hollow valve for opening and closing at least one of the air inlet and the exhaust outlet, the metallic hollow valve including: a tubular valve stem and a valve head merging into the valve stem; the valve stem and the valve head together delimiting a hollow space; the valve stem having an outer diameter of between 7 mm and 11 mm and an inner diameter of between 4.5 mm and 7 mm; and wherein the valve head has an outer diameter that is enlarged compared to the outer diameter of the valve stem.

8. The internal combustion engine according to claim 7, further comprising a valve seat surrounding at least one of the air inlet and the exhaust outlet, wherein the metallic hollow valve engages via a contact section against the valve seat in a closed position, in which the metallic hollow valve closes at least one of the air inlet and the exhaust outlet; and wherein the metallic hollow valve is hard-faced at least in a region of the contact section.

9. The internal combustion engine according to claim 8, wherein the metallic hollow valve is hard-faced via at least one of a plasma powder deposit welded Iron filler material and a plasma powder deposit welded Cobalt filler material.

10. A utility vehicle, comprising: an internal combustion engine including: at least one cylinder including a combustion chamber having an air inlet and an exhaust outlet; a valve drive including a metallic hollow valve for opening and closing at least one of the air inlet and the exhaust outlet, the metallic hollow valve including: a tubular valve stem and a valve head merging into the valve stem; the valve stem and the valve head together delimiting a hollow space; the valve stem having an outer diameter of between 8 mm and 11 mm, an inner diameter of between 5 mm and 7 mm, and a wall thickness of between 1.5 mm and 5 mm; and wherein the valve head has an outer diameter that is enlarged compared to the outer diameter of the valve stem.

11. The utility vehicle according to claim 10, wherein the valve head has at least one of a hard-faced iron material deposit and a hard-faced cobalt material deposit.

12. The utility vehicle according to claim 10, wherein the internal combustion engine further includes a valve seat surrounding at least one of the air inlet and the exhaust outlet, wherein the metallic hollow valve engages via a contact section against the valve seat in a closed position, in which the metallic hollow valve closes the at least one of the air inlet and the exhaust outlet; and wherein the metallic hollow valve includes at least one of a hard-faced iron material deposit and a hard-faced cobalt material deposit disposed at least in a region of the contact section.

13. The utility vehicle according to claim 10, wherein at least one of: the valve head includes a head base facing away from the valve stem, and wherein the head base has a base thickness between 2 mm and 5 mm; and the valve stem has a wall thickness between 1.5 mm and 5 mm.

14. The utility vehicle according to claim 10, wherein the metallic hollow valve further includes a valve neck arranged between valve stem and valve head, wherein the valve neck has a wall thickness between 1.5 mm and 5 mm.

15. The internal combustion engine according to claim 7, wherein the valve head includes a head base facing away from the valve stem, and wherein the head base has a base thickness between 2 mm and 5 mm.

16. The internal combustion engine according to claim 7, wherein the valve stem has a wall thickness between 1.5 mm and 5 mm.

17. The internal combustion engine according to claim 7, wherein the metallic hollow valve further includes a valve neck arranged between valve stem and valve head, wherein the valve neck has a wall thickness between 1.5 mm and 5 mm.

18. The metallic hollow valve according to claim 1, wherein the valve head includes at least one of a hard-faced iron material deposit and a hard-faced cobalt material deposit.

19. The metallic hollow valve according to claim 1, wherein the outer diameter of the valve stem is between 8 mm and 11 mm.

20. The metallic hollow valve according to claim 1, wherein the inner diameter of the valve stem is between 5 mm and 7 mm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The FIGURE shows a cross-sectional view of an exemplary metallic hollow valve according to the disclosure.

DETAILED DESCRIPTION

[0022] The only FIGURE shows an example of a metallic hollow valve 1 according to the invention in a longitudinal section along a centre longitudinal axis M of the valve stem 2 of the hollow valve. By way of the centre longitudinal axis M, an axial direction A is defined. Along the axial direction A, the valve stem 2 merges into a valve head 3, which compared with the valve stem 2 has an enlarged outer diameter d.sub.A. The valve stem 2 and the valve head 3 are integrally moulded onto one another. The valve head 3 can be produced by means of forging or by means of electrochemical machining.

[0023] As is evident from the FIGURE, the valve steam 2 and the valve head 3known also as valve disc to the person skilled in the arthave a common hollow space 4. This hollow space 4 is partly filled with a fluid, preferentially with sodium, which for the sake of clarity is not shown in the FIGURE. The valve stem 2 has an outer diameter d.sub.A of more than 7 mm. Preferably, the value for the outer diameter d.sub.A is between 8 mm and 11 mm. Furthermore, the valve stem has an inner diameter d.sub.I of at least 4.5 mm. Preferably, the value for the inner diameter d.sub.I is between 5 mm and 7 mm. Particularly preferably, the valve stem has a wall thickness d between 1.5 mm and 5 mm. Here, said wall thickness d is defined by the difference between the outer diameter d.sub.A and the inner diameter d.sub.I.

[0024] As is further evident from the representation of the FIGURE, the valve head 3 has a head base 5 facing away from the valve stem 2, which has a base thickness d.sub.B between 2 mm and 5 mm. Furthermore, the wall thickness d.sub.K of a valve neck 6 formed between the valve stem 2 and the valve head 3 can be between 1.5 mm and 5 mm.

[0025] The hollow valve 1 shown in the FIGURE can be employed as part of a valve drive in an internal combustion engine (not shown in the FIGURE) of a utility vehicle in order to open and close air inlets and/or exhaust outlets. Said air inlet or exhaust outlet can be surrounded by a valve seat, against which the hollow valve 1 lies with a contact section 7 in a closing position, in which it closes the air inlet and the exhaust outlet respectively. Said contact section 7, which is merely schematically indicated in the FIGURE, is exposed to particular mechanical and thermal loads during the operation of the valve drive in the internal combustion engine. For this reason, the hollow valve 1 can be designed hard-faced at least in the region of the contact section 7. Such hard facing of the contact section 7 can be produced in particular by means of plasma powder deposit welding, particularly preferably using Iron (Fe) or Cobalt (Co) as filler material.