Piston for an internal combustion engine

• US 9,726,109 B2
• Filed: 04/15/2013
• Issued: 08/08/2017
• 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
• Primary Examiner(s): Cronin, Stephen K
• Assistant Examiner(s): Tran, Long T
• Application Number:
  US14/395,237
• Publication Number:
  US 20150090215A1
• Time in Patent Office: 1,576 Days
• Field of Search: 1231936, 1231931, 1231933, 123 4135, 123 4136
• 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 having at least one cavity with an inner duct and configured to contain a heat transfer medium including liquid metal for dissipation of heat from the piston crown to an underside of the piston; and

a heat insulation region with an outer duct radially outward and fluidically separated from the inner duct for liquid metal and arranged between the ring section and the convection region to thermally insulate the ring section, wherein the inner duct for liquid metal is arranged is radially inside the outer duct.

2. The piston according to claim 1, wherein the inner duct for liquid metal is concentric to the outer duct.

3. The piston according to claim 2, wherein the outer duct and the inner duct for liquid metal are fluidically separated from one another by a dividing wall, wherein the dividing wall is constructed an integral component of the piston.

4. The piston according to claim 3, wherein the dividing wall, with a separate construction fluidically separating the outer duct and the inner duct for liquid metal, includes 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 dividing wall is fixed by clamping.

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

8. The piston according to claim 7, 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.

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

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

11. 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.

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

13. 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).

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

15. 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.

16. The piston according to claim 1, wherein the liquid metal is introduced into the inner duct as a paste or solid material.

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

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 including liquid metal 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 fluidically separating the outer duct from the inner duct for liquid metal, 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 the heat-insulating material includes at least one of air and a metal foam.

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