Piston for an internal combustion engine

Patent metadata

Field	Value
Publication number	US-9869269-B2
Application number	US-201414894902-A
Country	US
Kind code	B2
Filing date	May 28, 2014
Priority date	May 31, 2013
Publication date	Jan 16, 2018
Grant date	Jan 16, 2018

Abstract

A piston for an internal combustion engine may include a piston head and a piston skirt. The piston head may include a piston crown, an encircling fire land, an encircling ring belt having a plurality of ring grooves and an encircling cooling duct disposed radially inwards from the ring belt. The cooling duct may be open in an axial direction away from the fire land and may be at least partially closed via a closure element. The cooling duct may have a cooling duct base and a cooling duct ceiling. The closure element may be arranged on the piston head to define the cooling duct base in a position above a lowermost ring groove of the plurality of ring grooves.

First claim

The invention claimed is:

1. A piston for an internal combustion engine, comprising: a piston head and a piston skirt together defining a reciprocating axis; the piston head including a piston crown, an encircling fire land, an encircling ring belt including a plurality of ring grooves, and an encircling cooling duct disposed radially inwards from the encircling ring belt with respect to the reciprocating axis, the encircling cooling duct being open in an axial direction away from the encircling fire land and at least partially closed via a closure element, the encircling cooling duct having a cooling duct base and a cooling duct ceiling, wherein the closure element is arranged in the piston head to define the cooling duct base in a position above a lowermost ring groove of the plurality of ring grooves; wherein an axial height of the encircling fire land with respect to the reciprocating axis is 9% or less than a nominal diameter of the piston head; and wherein an axial extent between the piston crown and the cooling duct base with respect to the reciprocating axis is between 11% and 17% of the nominal diameter of the piston head.

2. The piston as claimed in claim 1 , wherein the cooling duct base via the closure element is arranged at a level of an intermediate ring groove of the plurality of ring grooves.

3. The piston as claimed in claim 1 , wherein the closure element is configured on the piston head to define an encircling annular gap disposed at the cooling duct base.

4. The piston as claimed in claim 1 , wherein the encircling cooling duct defines a height in an axial direction and a width in a radial direction with respect to the reciprocating axis, and wherein the height of the encircling cooling duct is 0.8 times to 1.7 times the width of the cooling duct.

5. The piston as claimed in claim 1 , wherein an axial extent between the piston crown and the cooling duct ceiling with respect to the reciprocating axis is between 3% and 7% of the nominal diameter of the piston head.

6. The piston as claimed in claim 1 , wherein the piston head further includes a combustion depression, and wherein the piston head defines a wall thickness in a radial direction with respect to the reciprocating axis between the combustion depression and the encircling cooling duct ranging from 2.5% to 4.5% of the nominal diameter of the piston head.

7. The piston as claimed in claim 6 , wherein the combustion depression includes an undercut in the radial direction.

8. The piston as claimed in claim 1 , wherein the closure element is configured as a separate component from the piston head.

9. The piston as claimed in claim 1 , wherein the piston head and the piston skirt are composed of at least two components connected non-releasably to one another.

10. The piston as claimed in claim 9 , wherein the at least two components include a piston main body and a piston ring element.

11. The piston as claimed in claim 10 , wherein the closure element is configured as one piece with the piston main body.

12. The piston as claimed in claim 10 , wherein the closure element is configured as one piece with the piston ring element.

13. The piston as claimed in claim 1 , wherein at least one of the piston head and the piston skirt is composed of a steel material.

14. A piston for an internal combustion engine, comprising: a piston head and a piston skirt together defining a reciprocating axis; the piston head including a piston crown, a circumferential fire land, a circumferential ring belt including a plurality of ring grooves, and an annular cooling duct disposed radially inwards from the circumferential ring belt with respect to the reciprocating axis, the annular cooling duct configured open in an axial direction away from the circumferential fire land; a closure element at least partially closing the annular cooling duct and defining a cooling duct base positioned away from the circumferential fire land in relation to a cooling duct ceiling, the closure element disposed on the piston head to position the cooling duct base above a lowermost ring groove of the plurality of ring grooves; wherein the annular cooling duct defines a height in the axial direction of the reciprocating axis and a width in a radial direction of the reciprocating axis, and the height of the annular cooling duct is from 0.8 times to 1.7 times the width of the annular cooling duct; and wherein an axial extent between the piston crown and the cooling duct ceiling with respect to the reciprocating axis is from 3% to 7% of a nominal diameter of the piston head.

15. The piston as claimed in claim 14 , wherein the closure element extends in the radial direction of the reciprocating axis away from the circumferential ring belt and provides an annular gap at the cooling duct base.

16. A piston for an internal combustion engine, comprising: a piston body having a center axis and a piston ring element coupled to the piston body, the piston body and the piston ring element together defining a piston head; the piston head including a piston crown, a circumferential fire land, a circumferential ring belt including a plurality of ring grooves, and an annular cooling duct disposed radially inwards from the circumferential ring belt with respect to the center axis, the annular cooling duct configured open in an axial direction away from the circumferential fire land; a closure element at least partially closing the annular cooling duct and defining a cooling duct base positioned away from the circumferential fire land in relation to a cooling duct ceiling, the closure element connected integrally with the piston body and arranged on the piston head to provide an annular gap at the cooling duct base; and wherein the closure element positions the cooling duct base at a level between a first ring groove and a second ring groove of the plurality of ring grooves.

17. The piston as claimed in claim 16 , wherein the second ring groove is disposed between the first ring groove and a third ring groove of the plurality of ring grooves, and wherein the first ring groove is disposed proximal to the circumferential fire land in relation to the third ring groove.

18. The piston as claimed in claim 16 , wherein the piston head further includes a combustion depression disposed radially inwards of the annular cooling duct with respect to the center axis, and wherein the closure element extends in a radial direction of the center axis from a radially outer wall of the combustion depression towards the circumferential ring belt.

19. The piston as claimed in claim 18 , wherein the piston body and the piston ring element are coupled to one another via a weld seam disposed in the outer wall of the combustion depression, the closure element arranged integrally connected to a first part of the outer wall of the combustion depression defined by the piston body, and wherein the piston ring element defines a second part of the outer wall of the combustion depression, the piston crown, the fire land, and the circumferential ring belt.

20. The piston as claimed in claim 16 , wherein the piston body includes a piston skirt, and wherein a compression height defined by the piston head together with the piston skirt is from 38% to 45% of a nominal diameter of the piston head.

Assignees

• Mahle Int Gmbh

Inventors

• Scharp Rainer
• Kemnitz Peter

Classifications

• F02F3/00

  Pistons · CPC title

• F02F3/16

  having cooling means · CPC title

• F02F3/22 Primary

  the fluid being liquid · CPC title

• F01P3/08

  Cooling of piston exterior only, e.g. by jets · CPC title

• F02F3/02

  having means for accommodating or controlling heat expansion · CPC title