Cast light metal piston

• US 10,655,561 B2
• Filed: 03/06/2013
• Issued: 05/19/2020
• Est. Priority Date: 03/07/2012
• Status: Active Grant

• Current Assignee: Mahle International GmbH (MAHLE-STIFTUNG GmbH)
• Original Assignee: Mahle International GmbH (MAHLE-STIFTUNG GmbH)
• Inventors: Adelmann, Jochen, Braig, Ralf, Marquardt, Michael
• Primary Examiner(s): Amick, Jacob M
• Assistant Examiner(s): Morales, Omar
• Application Number:
  US14/383,226
• Publication Number:
  US 20150027400A1
• Time in Patent Office: 2,631 Days
• Field of Search: 1231936
• CPC Class Codes: F01P 3/10 Cooling by flow of coolant through pistons
• CPC Class Codes: F02F 2003/0007 Monolithic pistons; One piece constructions; Casting of pistons
• CPC Class Codes: F02F 3/0084 the pistons being constructed from specific materials
• CPC Class Codes: F02F 3/20 the means being a fluid flowing through or along piston
• CPC Class Codes: F02F 3/22 the fluid being liquid

Abstract

A cast light metal piston for an internal combustion engine may include a piston crown and a piston skirt adjoining the piston crown. The piston skirt may include two skirt walls arranged on a pressure side and a counterpressure side, respectively. The piston skirt may have two box walls connecting the skirt walls, which conically taper towards one another in a direction of the piston crown. The piston may include an annularly encircling cooling channel. A thickness of the piston crown may amount to a maximum of 4.5 mm.

Claims

1. A cast light metal piston having a reciprocating axis for an internal combustion engine, comprising:

a piston crown and a piston skirt adjoining the piston crown, the piston skirt including;

two skirt walls arranged on a pressure side and a counterpressure side, respectively;

a first box wall connecting the skirt wall on the pressure side to the skirt wall on the counterpressure side, the first box wall having a first pin hub positioned between a pressure side portion of the first box wall and a counterpressure side portion of the first box wall;

a second box wall connecting the skirt wall on the pressure side to the skirt wall on the counterpressure side, the second box wall having a second pin hub positioned between a pressure side portion of the second box wall and a counterpressure side portion of the second box wall;

an annularly encircling cooling channel;

wherein a thickness of the piston crown amounts to a maximum of 4.5 mm;

wherein the pressure side portion of the first box wall and the pressure side portion of the second box wall conically taper toward one another in a direction toward the skirt wall arranged on the pressure side and conically taper toward one another in a direction toward the piston crown;

wherein the counterpressure side portion of the first box wall and the counterpressure side portion of the second box wall conically taper from respective first and second end portions toward one another in the direction toward the piston crown;

wherein the skirt wall arranged on the pressure side is shorter in a circumferential direction of the reciprocating axis than the skirt wall arranged on the counterpressure side; and

wherein the first and second box walls are separated from one another by a distance in a radial direction of the reciprocating axis, and wherein the distance between the pressure side portion of the first box wall at the first pin hub and the pressure side portion of the second box wall at the second pin hub is greater than the distance between the counterpressure side portion of the first box wall at the first pin hub and the counterpressure side portion of the second box wall at the second pin hub.

2. The piston according to claim 1, wherein the thickness of the piston crown amounts to a maximum of 3.5 mm.

3. The piston according to claim 1, wherein the skirt wall arranged on the pressure side has a thinner thickness in a circumferentially middle region than in circumferential end regions coupled to the pressure side portions of the first and second box walls.

4. The piston according to claim 1, wherein the first and second box walls are in a biconvex arrangement.

5. The piston according to claim 1, wherein the cooling channel is formed via at least one of a salt and sand core.

6. The piston according to claim 1, wherein the piston crown and skirt are aluminum.

7. The piston according to claim 1, wherein the counterpressure side portion of the first box wall and the counterpressure side portion of the second box wall diverge away from one another in a direction of the skirt wall arranged on the counterpressure side.

8. The piston according to claim 1, wherein the pressure side portion of the first box wall and the pressure side portion of the second box wall are structured convexly to one another along a direction extending between the skirt wall on the pressure side and the reciprocating axis.

9. An internal combustion engine, comprising:

a cast light metal piston having a reciprocating axis, including;

a piston crown adjoining a piston skirt, the piston skirt including a pin hub, two skirt walls arranged on a pressure side and a counterpressure side, respectively, and first and second box walls connecting the skirt walls to the pin hub, the first and second box walls conically tapering towards one another in a direction of the piston crown;

an annularly encircling cooling channel arranged in the piston crown;

wherein a thickness of the piston crown is 4.5 mm or less;

wherein each of the first and second box walls comprises a pressure side portion arranged between the pin hub and the skirt wall arranged on the pressure side and a counterpressure side portion arranged between the pin hub and the skirt wall arranged on the counterpressure side;

wherein the pressure side portions of the first and second box walls conically taper from respective first and second end portions towards one another in a direction towards the skirt wall on the pressure side; and

wherein the counterpressure side portions of the first and second box walls diverge away from one another in a direction towards the skirt wall on the counterpressure side

wherein the first and second box walls are separated from one another by a distance in a radial direction of the reciprocating axis, and wherein the distance between the pressure side portion of the first box wall at the first pin hub and the pressure side portion of the second box wall at the second pin hub is greater than the distance between the counterpressure side portion of the first box wall at the first pin hub and the counterpressure side portion of the second box wall at the second pin hub.

10. The internal combustion engine according to claim 9, further comprising two spray nozzles for piston cooling, wherein one spray nozzle is directed at an inflow of the cooling channel and the other spray nozzle is directed at a bottom side of the piston crown facing the piston skirt.

11. The internal combustion engine according to claim 9, wherein the thickness of the piston crown is 3.5 mm or less.

12. The internal combustion engine according to claim 9, wherein the skirt wall arranged on the pressure side is shorter in a circumferential direction of the piston than the skirt wall arranged on the counterpressure side.

13. The internal combustion engine according to claim 9, wherein the pressure side portions of the first and second box walls are structured convexly to one another along a radial direction with respect to the reciprocating axis.

14. The internal combustion engine according to claim 9, wherein a distance in a radial direction of the reciprocating axis between the counterpressure side portions of the box walls at the pin hub is less than that defined between the pressure side portions of the first and second box walls at the pin hub.

15. The internal combustion engine according to claim 9, wherein the cooling channel has a varying diameter.

16. The internal combustion engine according to claim 9, wherein the piston crown and skirt are aluminum.

17. A light metal piston for an internal combustion engine, comprising:

a piston crown having a central region defining a thickness of 4.5 mm or less;

a piston skirt coupled to the piston crown;

an annular cooling channel disposed in the piston crown;

the piston skirt including a first skirt wall arranged on a pressure side, a second skirt wall arranged on a counterpressure side, a first box wall connecting the first skirt wall to the second skirt wall, a second box wall connecting the first skirt wall to the second skirt wall and arranged at a distance from the first box wall, and a pin hub extending along a direction transverse to the first box wall and the second box wall, wherein the pressure side is separated from the counterpressure side via the pin hub;

wherein each of the first box wall and the second box wall comprises a pressure side portion arranged between the pin hub and the first skirt wall and a counterpressure side portion arranged between the pin hub and the second skirt wall;

wherein the first box wall and the second box wall taper towards one another in a direction of the piston crown, and wherein the pressure side portion of the first box wall and the pressure side portion of the second box wall conically taper from respective first and second end portions towards one another in a direction towards the first skirt wall;

wherein the counterpressure side portion of the first box wall and the counterpressure side portion of the second box wall diverge away from one another in a direction towards the second skirt wall; and

wherein the first and second box walls are separated from one another by a distance in a radial direction of the reciprocating axis, and wherein the distance between the pressure side portion of the first box wall at the first pin hub and the pressure side portion of the second box wall at the second pin hub is greater than the distance between the counterpressure side portion of the first box wall at the first pin hub and the counterpressure side portion of the second box wall at the second pin hub.

18. The piston according to claim 17, wherein the pressure side portion of the first box wall and the pressure side portion of the second box wall are structured to extend convexly to one another between the first skirt wall and the pin hub.

19. The piston according to claim 17, wherein the cooling channel has a varying diameter.

20. The piston according to claim 17, wherein the first skirt wall is shorter in a circumferential direction of the piston than the second skirt wall.