# US 8,539,926 B2 · Piston, cylinder and piston assembly and piston ring for a piston

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- Number: US 8,539,926 B2
- Document ID: US8539926B2
- Status: Granted
- Kind: B2
- Application number: 12/652,846
- Filed: 2010-01-06
- Published: 2010-06-17
- Granted: 2013-09-24
- Earliest claimed: 2007-07-06
- Assignees: Mahle Koenig Kommanditgesellschaft GmbH & Co. KG
- Applicants: Karlheinz Langner; Reiner Ulrich
- Inventors: Karlheinz Langner; Reiner Ulrich
- Web page: https://patentgrep.com/patent/US8539926B2

## CPC

- F16J 1/001: {One-piece pistons}
- F02B 25/14: using reverse-flow scavenging, e.g. with both outlet and inlet ports arranged near bottom of piston stroke
- F02F 3/027: {the skirt wall having cavities}
- F02F 3/24: having means for guiding gases in cylinders, e.g. for guiding scavenging charge in two-stroke engines
- F02F 3/0076: {the inside of the pistons being provided with ribs or fins}
- Y10T 29/49249: Piston making
- F16J: PISTONS {(specially adapted for dampers F16F9/32)}; CYLINDERS; SEALINGS
- F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G)
- F02F: CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A piston includes a piston head, two skirt walls disposed opposite one another and at least one pin bearing disposed between the skirt walls and supported on the piston head. Each skirt wall extends over a partial region of the periphery of the piston or piston head. The two skirt walls are connected by at least one self-supporting support wall disposed at a distance from the piston head. A cylinder and piston assembly and a piston ring for a cylinder, are also provided.

## Claims

### Claim 1

A piston, comprising:
a piston head;
two skirt walls lying opposite one another and each extending over a partial area of an outer contour of the piston or said piston head;
at least one pin bearing braced on said piston head and disposed between said skirt walls;
at least one supporting wall interconnecting said skirt walls and disposed at a distance from said piston head, said at least one supporting wall bordering an intermediate space separating said piston head from said at least one supporting wall in a self-supporting fashion between said skirt walls, and said at least one supporting wall not being connected with said at least one pin bearing; and
a piston ring disposed below said at least one pin bearing in at least one circumferential groove formed in said skirt walls and formed in said at least one supporting wall separated from said piston head by said intermediate space.

### Claim 2 (depends on 1)

The piston according to claim 1, wherein said at least one self-supporting wall is strip-shaped.

### Claim 3 (depends on 1)

The piston according to claim 1, wherein said supporting wall has a curvature matching a curvature of said skirt walls.

### Claim 4 (depends on 3)

The piston according to claim 3, wherein said supporting wall has a shape of a section of a cylindrical ring.

### Claim 5 (depends on 1)

The piston according to claim 1, wherein one of said skirt walls extends over an angle of 55 to 90° and/or the other of said skirt walls extends over an angle of 90 to 115° along an outer contour or edge of said piston head or is shaped onto said piston head.

### Claim 6 (depends on 1)

The piston according to claim 1, wherein one of said skirt walls extends over an angle of 60 to 80° and/or the other of said skirt walls extends over an angle of 100 to 110° along an outer contour or edge of said piston head or is shaped onto said piston head.

### Claim 7 (depends on 5)

The piston according to claim 5, wherein said skirt walls have equal heights.

### Claim 8 (depends on 6)

The piston according to claim 6, wherein said skirt walls have equal heights.

### Claim 9 (depends on 1)

The piston according to claim 1, wherein side surfaces of said skirt walls, said at least one supporting wall connecting said skirt walls and a lower edge of said piston head, define a cutout leaving said at least one pin bearing free.

### Claim 10 (depends on 1)

The piston according to claim 1, wherein said at least one supporting wall is disposed in an area of said skirt walls at a height of 50 to 90% of a height of said skirt walls or of a height of a taller one of said skirt walls measured from said piston head, and/or said at least one supporting wall has a height of 10 to 25% of said height of said skirt walls or of said height of said taller skirt wall.

### Claim 11 (depends on 1)

The piston according to claim 1, wherein said at least one supporting wall is disposed in an area of said skirt walls at a height of 55 to 80% of a height of said skirt walls or of a height of a taller one of said skirt walls measured from said piston head, and/or said at least one supporting wall has a height of 10 to 15% of said height of said skirt walls or of said height of said taller skirt wall.

### Claim 12 (depends on 1)

The piston according to claim 1, wherein said at least one supporting wall is placed at an interval from said at least one pin bearing and/or said at least one supporting wall is connected exclusively with said skirt walls and carried by them exclusively.

### Claim 13 (depends on 1)

The piston according to claim 1, which further comprises rounded transitional sections from the supporting walls and/or wall part to at least one of said piston head or said skirt walls.

### Claim 14 (depends on 1)

The piston according to claim 1, wherein said at least one supporting wall and said skirt walls have a circular outer contour at a level of said at least one supporting wall or at an end area of said skirt walls.

### Claim 15 (depends on 1)

The piston according to claim 1, wherein said piston ring has a mouth opening fixed in an outer contour area of one of said skirt walls.

### Claim 16 (depends on 15)

The piston according to claim 15, wherein said piston ring is a prestressed negative oval with a prestressing withdrawn in an area of said mouth opening of said piston ring or lessened relative to a tensioning in a diametrically opposite area of said piston ring and/or said piston ring in said area of said mouth opening and in an area lying opposite said mouth opening is configured to be radially reinforced or expanded, optionally with a reinforcement increasing continuously from an area with a least ring thickness to a maximum value exceeding said least ring thickness measured in radial direction in said area of least ring thickness by 20 to 40% and/or said radially reinforced or expanded area of said piston ring extends over a central angular range of 70 to 110°.

### Claim 17 (depends on 16)

The piston according to claim 16, wherein said prestressing is withdrawn or lessened by 10 to 30%, said reinforcement increases by 25 to 35% and said radially reinforced or expanded area extends over a central angular range of 80 to 190°.

### Claim 18 (depends on 1)

The piston according to claim 1, wherein said piston ring is supported at an interval of from 50 to 88% of a height of the piston from said piston head in said at least one circumferential groove.

### Claim 19 (depends on 1)

The piston according to claim 1, wherein said piston ring is supported at an interval of from 60 to 88% of a height of the piston from said piston head in said at least one circumferential groove.

### Claim 20 (depends on 1)

The piston according to claim 1, which further comprises a circumferential wall reinforcement disposed on an inner side of said skirt walls and said at least one supporting wall in vicinity of said at least one circumferential groove.

### Claim 21 (depends on 20)

The piston according to claim 20, wherein said wall reinforcements have a height and a width exceeding a height of said at least one circumferential groove or a depth of said annular groove by about 50 to 200%.

### Claim 22 (depends on 20)

The piston according to claim 20, wherein said wall reinforcements have a height and a width exceeding a height of said at least one circumferential groove or a depth of said annular groove by about 80 to 150%.

### Claim 23 (depends on 1)

A cylinder and piston assembly, comprising:
a cylinder; and
a piston according to claim 1 belonging to or supported within said cylinder.