Piston for an internal combustion engine

Patent metadata

Field	Value
Publication number	US-2016115901-A1
Application number	US-201414894902-A
Country	US
Kind code	A1
Filing date	May 28, 2014
Priority date	May 31, 2013
Publication date	Apr 28, 2016
Grant date	—

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

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 having a plurality of ring grooves and an encircling cooling duct disposed radially inwards from the ring belt with respect to the reciprocating axis, wherein the cooling duct is open in an axial direction away from the fire land and is at least partially closed via a closure element, the 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.

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 cooling duct base via the closure element is arranged between a first ring groove and a second ring groove of the plurality of ring grooves.

4 . 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.

5 . The piston as claimed in claim 1 , wherein an axial height of the fire land with respect to the reciprocating axis is 9% or less than a nominal diameter of the piston head.

6 . The piston as claimed in claim 5 , 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.

7 . The piston as claimed in claim 5 , wherein the 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 cooling duct is 0.8 times to 1.7 times the width of the cooling duct.

8 . The piston as claimed in claim 5 , 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.

9 . The piston as claimed in claim 5 , wherein the piston head and the piston skirt together define a compression height, and wherein the compression height is between 38% and 4 5 % of the nominal diameter of the piston head.

10 . The piston as claimed in claim 5 , 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 cooling duct ranging from 2.5% and to 4.5% of the nominal diameter of the piston head.

11 . The piston as claimed in claim 10 , wherein the combustion depression includes an undercut in the radial direction.

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

13 . 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.

14 . The piston as claimed in claim 13 , wherein the at least two components include a piston main body and a piston ring element.

15 . The piston as claimed in claim 14 , wherein the closure element is configured as one piece with the piston main body.

16 . The piston as claimed in claim 14 , wherein the closure element is configured as one piece with the piston ring element.

17 . 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.

18 . The piston as claimed in claim 2 , wherein the closure element is configured on the piston head to define an annular gap disposed at the cooling duct base.

19 . The piston as claimed in claim 2 , wherein an axial height of the fire land with respect to the reciprocating axis is 9 percent or less than a nominal diameter of the piston head.

20 . A piston for an internal combustion engine, comprising:
a piston head and a piston skirt together defining a reciprocating axis, wherein the piston head includes:
a piston crown;
a combustion bowl;
a circumferential fire land;
a circumferential ring belt positioned axially towards the piston skirt in relation to the fire land with respect to the reciprocating axis, the ring belt including a plurality of ring grooves; and
an annular cooling duct disposed radially inwards of the ring belt with respect to the reciprocating axis, wherein the cooling duct is open in a direction away from the fire land and is at least partially closed by a closure element, the closure element defining a cooling duct base positioned away from the fire land in relation to a cooling duct ceiling;
wherein the plurality of ring grooves include a first ring groove, a second ring groove positioned between the first ring groove and a third ring groove, wherein the third ring groove is positioned away from the fire land with respect to the first ring groove and the second ring groove;
wherein the closure element is configured on the piston head to position the cooling duct base above the third ring groove and at least in a position commensurate with the second ring groove.

Assignees

• Mahle Int Gmbh

Inventors

• Scharp Rainer
• Kemnitz Peter

Classifications

• F02F3/00

  Pistons · CPC title

• F01P3/08

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

• F02F3/20

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

• F02F3/16

  having cooling means · CPC title

• F02F3/02

  having means for accommodating or controlling heat expansion · CPC title