ASYMMETRIC PISTON

• US 20160258382A1
• Filed: 03/04/2015
• Published: 09/08/2016
• Est. Priority Date: 03/04/2015
• Status: Active Grant

• Current Assignee: Mahle International GmbH (MAHLE-STIFTUNG GmbH)
• Original Assignee: Mahle International GmbH (MAHLE-STIFTUNG GmbH)
• Inventors: Wirkkala, Kenneth L. II, Muscas, Iosif, Perrone, Luiz
• Granted Patent: US 9,759,156 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B21K 1/185 with cooling channels
• CPC Class Codes: F02F 2003/0007 Monolithic pistons; One piece constructions; Casting of pistons
• CPC Class Codes: F02F 2003/0061 by welding
• CPC Class Codes: F02F 3/003 the parts being connected by casting, brazing, welding or clamping
• CPC Class Codes: F02F 3/0069 the crown and skirt being interconnected by the gudgeon pin
• CPC Class Codes: F02F 3/025 having circumferentially slotted piston skirts, e.g. T-slots
• 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
• CPC Class Codes: F02F 3/26 having combustion chamber in piston head the surface thereof being covered F02F3/14

Abstract

Exemplary pistons and methods of making the same are disclosed. An exemplary piston may include a crown defining a combustion bowl and a ring land extending circumferentially around the combustion bowl. Exemplary pistons may further include a skirt supporting the crown. The skirt may include a pair of pin bosses defining a pin bore configured to receive a piston pin, and two opposing skirt supports defining surfaces configured to slide along a cylinder bore surface. The skirt supports each define a different radial stiffness.

Claims

1. A piston, comprising:

a crown defining a combustion bowl and a ring land extending circumferentially around the combustion bowl, the crown defining at least in part a cooling gallery extending circumferentially about the piston; and

a skirt supporting the crown, the skirt including a pair of pin bosses, the pin bosses each defining a pin bore configured to receive a piston pin along a pin bore axis extending between the pin bosses, the skirt including two opposing skirt supports defining surfaces configured to slide along a cylinder bore surface, wherein a first one of the skirt supports defines an opening extending parallel to the pin bore axis such that the first one of the skirt supports defines a radial stiffness different from a second one of the skirt supports.

2. The piston of claim 1, wherein the opening extends through an upper surface of the skirt panel.

3. The piston of claim 1, wherein opposite lateral ends of the opening define an acute angle with a longitudinal piston axis.

4. The piston of claim 1, wherein at least one of the skirt supports defines a varying thickness running along the associated skirt surface.

5. The piston of claim 4, wherein the varying thickness decreases in magnitude from an upper portion of the skirt support to a lower portion of the skirt support.

6. The piston of claim 1, wherein at least one of the crown and the skirt is forged.

7. The piston of claim 6, wherein the crown and skirt are forged from a single monolithic piece.

8. The piston of claim 1, wherein at least one of the crown and the skirt is cast.

9. The piston of claim 1, wherein the crown and skirt are one of welded and bonded together.

10. The piston of claim 9, wherein the crown and skirt each define a radially inner joining surface and a radially outer annular joining surface, and the crown and skirt are joined together along the radially inner and radially outer annular joining surfaces.

11. The piston of claim 1, wherein one of the first and second skirt supports defines at least a second opening configured to permit fluid communication between the cooling gallery and an engine crankcase.

12. The piston of claim 1, wherein the radial stiffness of the second one of the skirt supports is at least twice the radial stiffness of the first one of the skirt supports.

13. A method of making a piston, comprising:

forming a crown defining a combustion bowl and a ring land extending circumferentially around the combustion bowl; and

providing a skirt supporting the crown, the skirt including a pair of pin bosses, the pin bosses each defining a pin bore configured to receive a piston pin, the skirt including two opposing skirt supports defining surfaces configured to slide along a cylinder bore surface; and

establishing a first one of the skirt supports as defining an opening extending parallel to the pin bore axis such that a radial stiffness of the first skirt support is different from a radial stiffness of the second one of the skirt supports.

14. The method of claim 13, further comprising establishing the opening as extending through an upper surface of the skirt panel.

15. The method of claim 13, further comprising establishing opposite lateral ends of the opening as defining an acute angle with a longitudinal piston axis.

16. The method of claim 13, further comprising forging at least one of the crown and the skirt.

17. The method of claim 16, wherein the crown and skirt are forged from a single monolithic piece.

18. The method of claim 13, further comprising joining the crown and skirt together in one of a welding process and a bonding process.

19. The method of claim 18, wherein the crown and skirt each define a radially inner joining surface and a radially outer annular joining surface, and the crown and skirt are joined together along the radially inner and radially outer annular joining surfaces.

20. The method of claim 13, further comprising establishing one of the first and second skirt supports as defining at least a second opening configured to permit fluid communication between the cooling gallery and an engine crankcase.