Piston for an internal combustion engine

Patent metadata

Field	Value
Publication number	US-11719186-B2
Application number	US-201917273090-A
Country	US
Kind code	B2
Filing date	Sep 16, 2019
Priority date	Sep 21, 2018
Publication date	Aug 8, 2023
Grant date	Aug 8, 2023

Abstract

The present disclosure relates to a piston for an internal combustion engine. The piston comprises a cover which at least partially covers a piston basehead of the piston. A heat-isolating air gap is formed between the cover and the piston basehead, which is fluidically connected to a combustion chamber and/or an upper side of the cover facing away from the heat-isolating air gap. The fluidic connection permits a fluid exchange to take place between the heat-isolating air gap and the combustion chamber. In this way, a pressure gradient can be reduced between the combustion chamber and the heat-isolating air gap. As a result, the cover is/can be kept thin without being deformed during combustion.

First claim

What is claimed is:

1. A piston for an internal combustion engine comprising:
a piston crown for a piston-side delimitation of a combustion chamber of the internal combustion engine; and
a cover which at least partially covers the piston crown, wherein, directly between the cover and the piston crown, there is formed a thermally insulating gap which has a fluidic connection to the combustion chamber and/or to a top side, averted from the thermally insulating gap, of the cover,
wherein:
the piston crown has a piston depression, and the cover is at least partially arranged in the piston depression and/or adapted to the piston depression;
the piston depression is in the form of an omega-shaped depression and/or a stepped depression, and the cover at least partially has an omega-shaped and/or a stepped cross section; and
the fluidic connection is formed at least partially by an annular gap between an inner circumferential edge of the cover and a central elevation of the piston depression.

2. The piston as claimed in claim 1 , wherein the thermally insulating gap is an air gap.

3. The piston as claimed in claim 1 , wherein:
the fluidic connection is designed to allow a pressure approximation and/or a pressure equalization between the combustion chamber and the thermally insulating gap, and/or
a pressure on the top side of the cover and a pressure on a rear side, which faces toward the thermally insulating gap, of the cover are approximated and/or substantially equalized during the operation of the internal combustion engine by means of the fluidic connection.

4. The piston as claimed in claim 1 , wherein:
the cover is arranged so as to separate a flame front during a combustion in the combustion chamber from the piston crown, and/or
the fluidic connection is arranged spaced apart from a fuel injection jet impingement region of the cover.

5. The piston as claimed in claim 4 , wherein the cover is arranged so as to separate the flame front during the combustion in the combustion chamber from a piston depression of the piston crown.

6. The piston as claimed in claim 1 , wherein:
the fluidic connection is formed at least partially by at least one annular gap between the piston crown and the cover.

7. The piston as claimed in claim 1 , wherein:
the fluidic connection is formed at least partially by an annular gap between an outer circumferential edge of the cover and the piston crown; and/or
the fluidic connection is formed at least partially by an annular gap between an inner circumferential edge of the cover and the piston crown.

8. The piston as claimed in claim 1 , wherein:
the fluidic connection is formed at least partially by at least one passage hole and/or at least one passage slot of the cover.

9. The piston as claimed in claim 8 , wherein:
multiple passage holes and/or multiple passage slots are included, arranged spaced apart from a fuel injection jet impingement region of the cover.

10. The piston as claimed in claim 1 , wherein:
the thermally insulating gap has a height greater than or equal to 0.5 mm and/or less than or equal to 2 mm, and/or approximately 1 mm; and/or
the thermally insulating gap) has a substantially constant height.

11. The piston as claimed in claim 1 , wherein the piston depression has a central elevation, and
the cover extends annularly around the central elevation.

12. The piston as claimed in claim 1 , wherein:
the fluidic connection is formed at least partially by an annular gap between an outer circumferential edge of the piston depression and an outer circumferential edge of the cover.

13. The piston as claimed in claim 1 , wherein:
a cross-sectional contour of the cover follows a cross-sectional contour of the piston depression.

14. The piston as claimed in claim 13 , wherein:
the cross-sectional contour of the cover follows the cross-sectional contour of the piston depression with a substantially constant spacing; and/or
the pistol depression is in the form of a stepped depression with a central elevation.

15. The piston as claimed in claim 1 , wherein the cover is in the form of a metal sheet.

16. The piston as claimed in claim 15 , wherein:
the metal sheet has a substantially constant metal sheet thickness; and/or
the metal sheet has a metal sheet thickness greater than or equal to 0.5 mm and/or less than or equal to 2 mm, and/or approximately 1 mm.

17. The piston as claimed in claim 1 , wherein:
the cover is welded to the piston crown and/or a depression of the pistol crown.

18. The piston as claimed in claim 17 , wherein:
the cover is welded by means of spot welding and/or friction welding.

19. A motor vehicle having a piston as claimed in claim 1 .

Assignees

• Man Truck & Bus Se

Inventors

• Malischewski Thomas
• Dietrich Jens
• Zülow Daniel

Classifications

• F02F3/26 Primary

  having combustion chamber in piston head (the surface thereof being covered F02F3/14) · CPC title

• B23K20/1265

  Non-butt welded joints, e.g. overlap-joints, T-joints or spot welds · CPC title

• F02F3/14 Primary

  within combustion chambers · CPC title

• F02B23/0603

  at least part of the interior volume or the wall of the combustion space being made of material different from the surrounding piston part, e.g. combustion space formed within a ceramic part fixed to a metal piston head · CPC title

• F02B23/0696

  W-piston bowl, i.e. the combustion space having a central projection pointing towards the cylinder head and the surrounding wall being inclined towards the cylinder wall · CPC title