PISTON FOR AN INTERNAL COMBUSTION ENGINE

• US 20150090215A1
• Filed: 04/15/2013
• Published: 04/02/2015
• Est. Priority Date: 04/18/2012
• Status: Active Grant

• Current Assignee: Mahle International GmbH (MAHLE-STIFTUNG GmbH)
• Original Assignee: Mahle International GmbH (MAHLE-STIFTUNG GmbH)
• Inventors: Boczek, Sascha-Oliver
• Granted Patent: US 9,726,109 B2
• Time in Patent Office: Days
• US Class Current: 123/193.6
• CPC Class Codes: F02F 3/18 the means being a liquid or solid coolant, e.g. sodium, in a closed chamber in piston
• CPC Class Codes: F02F 3/20 the means being a fluid flowing through or along piston

Abstract

A piston for an internal combustion engine may include an encircling ring section in a region of a piston crown. The piston may include a convection region, which has at least one cavity containing a heat transfer medium for dissipation of heat from the piston crown to an underside of the piston. The piston may include a heat insulating region, which is arranged between the ring section and the convection region and thermally insulates the ring section.

Claims

1. A piston for an internal combustion engine, comprising:

an encircling ring section in a region of a piston crown, a convection region, which has at least one cavity containing a heat transfer medium for dissipation of heat from the piston crown to an underside of the piston, and a heat insulation region, which is arranged between the ring section and the convection region and thermally insulates the ring section.

2. The piston according to claim 1, wherein the heat insulation region comprises an outer duct, and the cavity comprises an inner duct arranged radially inside the outer duct and concentric to the outer duct.

3. The piston according to claim 2, characterized in that wherein the outer duct and the inner duct are separated from one another by a dividing wall, wherein the dividing wall is constructed as at least one of a separate structural part and an integral component of the piston.

4. The piston according to claim 3, wherein the dividing wall, with a separate construction, is constructed from at least one of spring steel and plastic.

5. The piston according to claim 3, wherein:

the piston is a composite piston and includes a piston upper part, a piston lower part and the dividing wall, or

the piston is a composite piston and includes a piston upper part, a piston lower part and a ring section part.

6. The piston according to claim 5, wherein:

the piston upper part and the piston lower part are welded to one another, and wherein the dividing wall is fixed by at least one of a welded connection and clamping, or

the piston upper part and the piston lower part are welded to one another, and the ring section part with the piston upper part and the piston lower part are welded to one another, wherein the dividing wall forms an integral component of the piston lower part.

7. The piston according to claim 1, wherein the piston is at least one of steel and a light metal.

8. The piston according to claim 1, wherein the piston is produced by a casting process, and the dividing wall is constructed as an insert part.

9. The piston according to claim 1, wherein the heat transfer medium is a liquid metal.

10. The piston according to claim 3, wherein the dividing wall is arranged obliquely to a piston axis.

11. The piston according to claim 3, wherein the dividing wall has angled edge regions, via which the dividing wall rests on the piston.

12. The piston according to claim 3, wherein the dividing wall is formed from at least one of a spring plate, a polyimide and polyetheretherketone (PEEK).

13. The piston according to claim 6, wherein the dividing wall is arranged obliquely to a piston axis.

14. The piston according to claim 13, wherein the dividing wall has a cross-section of a plate spring and has a smaller diameter in a region of the piston crown than in a region of the underside.

15. The piston according to claim 6, wherein the dividing wall has angled edge regions via which the dividing wall rests on the piston.

16. The piston according to claim 9, wherein the liquid metal includes at least one of sodium, potassium and an alloy containing at least one of sodium and potassium.

17. The piston according to claim 10, wherein the dividing wall has a cross-section of a plate spring and has a smaller diameter in a region of the piston crown than in a region of the underside.

18. A piston for an internal combustion engine, comprising:

a piston crown having an encircling ring section for receiving piston rings, the piston crown having an outer duct in a region of the ring section and an inner duct arranged radially inside the outer duct and concentric to the outer duct;

a heat-insulating material arranged in the outer duct for thermally insulating the ring section;

a heat transfer medium enclosed in the inner duct for dissipation of heat from the piston crown to an underside of the piston by convection; and

a dividing wall separating the outer duct from the inner duct, wherein the dividing wall is arranged obliquely to a piston axis such that the dividing wall has a smaller diameter in the region of the piston crown than in a region of the underside.

19. The piston according to claim 18, wherein at least one of (i) the heat-insulating material includes at least one of air and a metal foam, and (ii) the heat transfer medium includes a liquid metal.

20. The piston according to claim 18, wherein in the dividing wall is at least one of a spring steel, a polyimide and polyetheretherketone.