Piston for an internal combustion engine

Patent metadata

Field	Value
Publication number	US-10174712-B2
Application number	US-201414894339-A
Country	US
Kind code	B2
Filing date	May 28, 2014
Priority date	May 31, 2013
Publication date	Jan 8, 2019
Grant date	Jan 8, 2019

Abstract

A piston for an internal combustion engine may include a piston crown and a piston skirt. The piston crown may include a piston head, a peripheral top land, a peripheral annular zone having a plurality of annular grooves and an annular closed cooling channel. The cooling channel may include a cooling channel base and a cooling channel cover. The cooling channel base may be arranged above the lower annular groove in relation to a region of combustion.

First claim

The invention claimed is:

1. A piston for an internal combustion engine, comprising: a piston crown and a piston skirt together defining a reciprocating axis, the piston crown including a piston head, a combustion recess, a peripheral top land, a peripheral annular zone having a plurality of annular grooves and an annular closed cooling channel including a cooling channel base and a cooling channel cover, the cooling channel base arranged above a lowest annular groove of the plurality of annular grooves;
a peripheral recess extending at least partially about the piston crown and disposed below the cooling channel base relative to the piston head;
the piston crown defining a wall thickness in a radial direction with respect to the reciprocating axis between the combustion recess and the cooling channel ranging from 2.5% to 4.5% of a nominal diameter of the piston crown;
wherein the top land defines an axial extent with respect to the reciprocating axis of 9% or less than the nominal diameter of the piston crown; and
wherein a distance between the piston head and the cooling channel base in an axial direction of the reciprocating axis is between 11% and 17% of the nominal diameter of the piston crown.

2. The piston as claimed in claim 1 , wherein the cooling channel base is arranged between a first annular groove and a second annular groove of the plurality of annular grooves, and wherein the first annular groove and the second annular groove are positioned towards the top land in relation to the lowest annular groove.

3. The piston as claimed in claim 1 , wherein the peripheral recess is delimited axially by the cooling channel base, and wherein the peripheral recess has a rounded transition defined between the cooling channel base and a wall of the combustion recess and between the cooling channel base and a wall of the annular zone.

4. The piston as claimed in claim 3 , wherein the peripheral recess has at least one of a U-shaped cross-section and an oval cross-section oriented in an axial direction of the reciprocating axis.

5. The piston as claimed in claim 1 , wherein the cooling channel defines an axial extent and a radial extent with respect to the reciprocating axis, and wherein the axial extent is between 0.8 times to 1.7 times the radial extent of the cooling channel.

6. The piston as claimed in claim 1 , wherein a distance between the piston head and the cooling channel cover is between 3% and 7% of the nominal diameter of the piston crown.

7. The piston as claimed in claim 1 , wherein the piston crown and the piston skirt together define a compression height, and wherein the compression height is between 38% and 45% of the nominal diameter of the piston crown.

8. The piston as claimed in claim 1 , wherein the combustion recess further includes an undercut, and wherein the wall thickness of the piston crown between the combustion recess and the cooling channel is defined in a region of the undercut.

9. The piston as claimed in claim 1 , wherein the piston crown is integral with the piston skirt to define a single-part piston.

10. The piston as claimed in claim 1 , wherein the piston crown and the piston skirt collectively are composed of at least two components connected nonreleasably to each other.

11. The piston as claimed in claim 10 , wherein the at least two components include at least a piston basic body and a peripheral recess edge reinforcement.

12. The piston as claimed in claim 10 , wherein the at least two components include at least a piston basic body and a peripheral piston head element.

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

14. The piston as claimed in claim 1 , wherein the wall thickness of the piston crown in the radial direction ranging from 2.5% to 4.5% of the nominal diameter is a minimum wall thickness in the radial direction defined by a wall of the piston crown arranged between the combustion recess and the cooling channel.

15. The piston as claimed in claim 1 , wherein the axial extent of the top land of 9% or less than the nominal diameter and the distance between the piston head and the cooling channel base in the axial direction of between 11% and 17% of the nominal diameter are each uniform throughout an extent of the cooling channel in a circumferential direction of the piston crown.

16. A piston for an internal combustion engine, comprising:
a piston crown and a piston skirt together defining a reciprocating axis;
the piston crown including a piston head, a combustion recess, a peripheral top land, a peripheral annular zone including a plurality of annular grooves, and an annular closed cooling channel disposed radially inwards from the annular zone in relation to the reciprocating axis, the cooling channel including a cooling channel base and a cooling channel cover, wherein the cooling channel base is arranged above a lowermost annular groove of the plurality of annular grooves with respect to the piston head;
the piston skirt including piston bosses connected to one another via running surfaces;
a peripheral recess disposed below the cooling channel base at least in a region of the running surfaces of the piston skirt, wherein the peripheral recess is open axially in a direction away from the cooling channel;
wherein the combustion recess includes an undercut, and the piston crown defines a wall thickness in a radial direction with respect to the reciprocating axis between a region of the undercut of the combustion recess and the cooling channel ranging from 2.5% to 4.5% of a nominal diameter of the piston crown;
wherein the top land defines an axial extent with respect to the reciprocating axis of 9% or less than the nominal diameter of the piston crown;
wherein the cooling channel defines an axial extent and a radial extent with respect to the reciprocating axis, the axial extent being between 0.8 times to 1.7 times the radial extent of the cooling channel;
wherein a distance between the piston head and the cooling channel cover in an axial direction of the reciprocating axis is between 3% and 7% of the nominal diameter of the piston crown; and
wherein a distance between the piston head and the cooling channel base in the axial direction is between 11% and 17% of the nominal diameter.

17. The piston as claimed in claim 16 , wherein the piston crown and the piston skirt are structured as at least two components connected nonreleasably to each other.

18. The piston as claimed in claim 17 , wherein the at least two components are secured to one another via a welded connection.

19. The piston as claimed in claim 16 , wherein the peripheral recess extends completely around the piston crown in a circumferential direction of the reciprocating axis.

20. The piston as claimed in claim 16 , wherein the axial extent of the top land of 9% or less than the nominal diameter, the axial extent of the cooling channel of 0.8 times to 1.7 times the radial extent of the cooling channel, the distance between the piston head and the cooling channel cover in the axial direction of between 3% and 7% of the nominal diameter, and the distance between the piston head and the cooling channel base in the axial direction of between 11% and 17% of the nominal diameter are each uniform throughout an extent of the cooling channel in a circumferential direction of the piston crown.

Assignees

• Mahle Int Gmbh

Inventors

• Scharp Rainer
• Kemnitz Peter

Classifications

• F02F3/18 Primary

  the means being a liquid or solid coolant, e.g. sodium, in a closed chamber in piston · CPC title

• F02F3/22 Primary

  the fluid being liquid · CPC title