Piston for an internal combustion engine

Patent metadata

Field	Value
Publication number	US-9771891-B2
Application number	US-201414894338-A
Country	US
Kind code	B2
Filing date	May 28, 2014
Priority date	May 31, 2013
Publication date	Sep 26, 2017
Grant date	Sep 26, 2017

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, a circumferential fire land, a circumferential ring belt having a plurality of ring grooves, and a circumferential cooling duct. The cooling duct may be open in a direction away from the fire land and may be at least partially closed by a closure element. The cooling duct may include a cooling duct bottom and a cooling duct ceiling. The piston skirt may have at least two piston bosses connected to one another via at least two running faces. At least one running face may have an inner face connected via a connecting land to an underside of the piston head.

First claim

The invention claimed is:

1. A piton 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 a circumferential cooling duct disposed radially inwards of the circumferential ring belt with respect to the reciprocating axis, wherein the circumferential cooling duct is open in a direction away from the circumferential fire land and is at least partially closed by a closure element, the circumferential cooling duct including a cooling duct bottom and a cooling duct ceiling; the piston skirt including at least two piston bosses connected to one another via at least two running faces, wherein one running face of the at least two running faces has an inner face connected via a connecting land to an underside of the piston head; wherein the piston head and the piston skirt together define a compression eight, the compression height ranging between 38% and 45% of a nominal diameter of the piston head; and wherein the circumferential fire land has an axial extent with respect to the reciprocating axis that is 9% or less than the nominal diameter of the piston head.

2. The piston as claimed in claim 1 , wherein the closure element is arranged in the piston head to define a circumferential annular gap at the cooling duct bottom.

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

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

5. The piston as claimed in claim 4 , wherein the at least two components include a main piston body and a piston ring element.

6. The piston as claimed in claim 5 , wherein the closure element is configured in one piece with the main piston body.

7. The piston as claimed in claim 5 , wherein the closure element is configured in one piece with the piston ring element.

8. The piston as claimed in claim 1 , wherein the closure element is arranged in the piston head to define the cooling duct bottom in a position above a lowermost ring groove of the plurality of ring grooves.

9. The piston as claimed in claim 8 , wherein the cooling duct bottom is arranged between a first ring groove and a second ring groove of the plurality of ring grooves, and wherein the first ring groove and the second ring groove are positioned towards the piston crown in relation to the lowermost ring groove.

10. The piston as claimed in claim 1 , wherein an axial extent between the piston crown and the cooling duct bottom with respect to the reciprocating axis is between 11% and 17% of the nominal diameter of the piston head.

11. The piston as claimed in claim 1 , wherein the circumferential 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 circumferential cooling duct is from 0.8 times to 1.7 times the width of the circumferential cooling duct.

12. 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.

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

14. The piston as claimed in claim 13 , wherein the combustion bowl includes an undercut extending in a radial direction of the piston head with respect to the reciprocating axis.

15. 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 combustion bowl; a circumferential fire land; a circumferential ring belt positioned away from a region of combustion in relation to the circumferential fire land, the circumferential ring belt including a plurality of ring grooves; and an annular cooling duct disposed radially inwards of the circumferential ring belt with respect to the reciprocating axis, wherein the annular cooling duct is open in a direction away from the circumferential fire land and is at least partially closed by a closure element, the closure element defining a cooling duct bottom positioned away from the circumferential fire land in relation to a cooling duct ceiling; the piston skirt including at least two piston bosses connected to one another via at least two running faces, and wherein one running face of the at least two running faces has a radially inner face connected via a connecting land to an axial underside of the piston head with respect to the reciprocating axis; and wherein the closure element is arranged on the piston head to define a circumferential annular gap in the annular cooling duct, and wherein the closure element is configured to position the cooling duct bottom above a lowermost ring groove in a region of an intermediate ring groove of the plurality of ring grooves in relation to the region of combustion.

16. The piston as claimed in claim 15 , wherein the circumferential annular gap is provided between the cooling duct bottom defined by the closure element and a wall of the combustion bowl.

17. The piston as claimed in claim 15 , wherein the closure element is coupled to the circumferential ring belt and is curved in a direction of the piston crown.

18. A piston having a center axis for an internal combustion engine, comprising: a piston head including a piston crown, a circumferential fire land, a circumferential ring belt positioned away from a region of combustion in relation to the circumferential fire land the circumferential ring belt including a plurality of ring grooves, and an annular cooling duct disposed radially inwards of the circumferential ring belt with respect to the center axis, the annular cooling duct configured open in a direction away from the circumferential fire land; a closure element at least partially closing the annular cooling duct and defining a cooling duct bottom positioned away from the circumferential fire land in relation to a cooling duct ceiling, the closure element extending from a bottom of the circumferential ring belt towards the piston crown and is arranged in the piston head to provide a circumferential annular gap at the cooling duct bottom; a piston skirt including at least two piston bosses connected to one another via at least two running faces, and a connecting land connecting a radially inner face of one of the at least two running faces, and a connecting land connecting a radially inner face of one of the at least two running faces to an axial underside of the piston head with respect to the reciprocating axis; and wherein the cooling duct bottom of the closure element is positioned at a level of an intermediate ring groove of the plurality of ring grooves.

19. The piston as claimed in claim 18 , wherein the closure element is connected integrally with the piston head.

20. The piston as claimed in claim 18 , wherein the plurality of ring grooves include a first ring groove, a second ring groove defining the intermediate ring groove, and a third ring groove disposed away from t

Assignees

• Mahle Int Gmbh

Inventors

• Scharp Rainer
• Kemnitz Peter

Classifications

• F02F3/00

  Pistons · CPC title

• F02F3/20

  the means being a fluid flowing through or along piston · CPC title

• F01P3/08

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

• F02F3/22 Primary

  the fluid being liquid · CPC title

• F02F3/16

  having cooling means · CPC title