Piston for an internal combustion engine

Patent metadata

Field	Value
Publication number	US-11054030-B2
Application number	US-202016821981-A
Country	US
Kind code	B2
Filing date	Mar 17, 2020
Priority date	Mar 18, 2019
Publication date	Jul 6, 2021
Grant date	Jul 6, 2021

Abstract

A piston for an internal combustion engine may include a piston head, an encircling fire land, and at least one annular groove structured to receive a piston ring and disposed contiguous to the fire land. The piston may include a first fire land portion having a first axial height h 1 , a second fire land portion having a second axial height h 2 , and a third fire land portion having a third axial height h 3 . The first fire land portion may have an upper external diameter D 1 . The third fire land portion may have a lower external diameter D 3 . A transition from the first to the second fire land portion may have a first external diameter D 12 . A transition from the second to the third fire land portion may have a second external diameter D 23 . The relationship (D 12 −D 23 )/h 2 >(D 23 −D 3 )/h 3 may apply.

First claim

The invention claimed is:

1. A piston for an internal combustion engine, comprising:
a piston head, an encircling fire land, and at least one annular groove structured to receive a piston ring, the at least one annular groove disposed contiguous to the fire land;
a first fire land portion disposed contiguous to the piston head, a second fire land portion, and a third fire land portion disposed contiguous to the at least one annular groove, the second fire land portion disposed between and connecting the first fire land portion and the third fire land portions;
the first fire land portion having a first axial height h 1 , the second fire land portion having a second axial height h 2 , and the third fire land portion having a third axial height h 3 ;
the first fire land portion having an upper external diameter D 1 , and the third fire land portion having a lower external diameter D 3 ;
wherein a transition from the first fire land portion to the second fire land portion has a first external diameter D 12 , and a transition from the second fire land portion to the third fire land portion has a second external diameter D 23 ; and
wherein (D 12 −D 23 )/h 2 >(D 23 −D 3 )/h 3 .

2. The piston according to claim 1 , wherein the second fire land portion is conical and has an external diameter that decreases in a consistent manner in a direction of the third fire land portion.

3. The piston according to claim 2 , wherein (D 12 −D 23 )≈0.5 mm.

4. The piston according to one claim 1 , further comprising a chamfer having an axial chamfer height hF of 0.5 mm or less, the chamfer disposed at one of (i) a transition from the piston head to the first fire land portion and (ii) a transition from the third fire land portion to the at least one annular groove.

5. The piston according to claim 4 , wherein h 1 =h 3 .

6. The piston according to claim 1 , wherein h 1 +h 3 =h 2 .

7. The piston according to claim 1 , wherein:
the second fire land portion includes a step; and
the second external diameter D 23 at the transition from the second fire land portion to the third fire land portion decreases in a stepped manner.

8. The piston according to claim 7 , wherein h 3 = 3 h 1 .

9. The piston according to claim 7 , wherein h 3 =h 1 .

10. The piston according to claim 1 , wherein the second fire land portion is curved and has an external diameter that decreases in a consistent and monotonous manner from the first external diameter D 12 to the second external diameter D 23 .

11. The piston according to claim 10 , wherein h 1 +h 3 =h 2 and h 1 =h 3 .

12. The piston according to claim 1 , wherein h 1 +h 2 +h 3 =5.25 mm.

13. The piston according to claim 1 , wherein the at least one annular groove includes a piston-head-proximal groove flank and a piston-head-distal groove flank, and wherein the piston-head-proximal groove flank and the piston-head-distal groove flank extend parallel to a radial direction.

14. The piston according to claim 1 , wherein the first fire land portion is structured cylindrical such that D 1 =D 12 .

15. The piston according to claim 1 , wherein the third fire land portion is structured cylindrical such that D 23 =D 3 .

16. The piston according to claim 1 , wherein (i) a transition from the piston heat to the first fire land portion, and (ii) a transition from the third fire land portion to the at least one annular groove are each structured without a chamfer.

17. The piston according to claim 1 , further comprising:
a first chamfer having an axial chamfer height hF of 0.2 mm or less disposed at a transition from the piston head to the first fire land portion; and
a second chamfer having an axial chamfer height hF of 0.2 mm or less disposed at a transition from the third fire land portion to the at least one annular groove.

18. The piston according to claim 1 , wherein the upper external diameter D 1 decreases in a consistent manner in a direction of the external diameter D 12 at the transition from the first fire land portion to the second fire land portion.

19. The piston according to claim 1 , wherein the external diameter D 23 decreases in a consistent manner in a direction of the at least one annular groove.

20. An internal combustion engine, comprising a cylinder and a piston disposed in the cylinder, the piston including:
a piston head, an encircling fire land, and at least one annular groove structured to receive a piston ring and disposed contiguous to the fire land;
a first fire land portion disposed contiguous to the piston head, a second fire land portion, and a third fire land portion disposed contiguous to the at least one annular groove, the second fire land portion disposed between and connecting the first fire land portion and the third fire land portion;
the first fire land portion having a first axial height h 1 , the second fire land portion having a second axial height h 2 , and the third fire land portion having a third axial height h 3 ;
the first fire land portion having an upper external diameter D 1 , and the third fire land portion having a lower external diameter D 3 ;
wherein a transition from the first fire land portion to the second fire land portion has a first external diameter D 12 , and a transition from the second fire land portion to the third fire land portion has a second external diameter D 23 , and
wherein (D 12 −D 23 )/h 2 >(D 23 −D 3 )/h 3 .

Assignees

• Mahle Int Gmbh

Inventors

• Beerens Christoph

Classifications

• F16J1/09

  with means for guiding fluids (F16J1/08 takes precedence) · CPC title

• F16J9/22 Primary

  Rings for preventing wear of grooves or like seatings · CPC title

• F02F3/00 Primary

  Pistons · CPC title

• F02F5/00

  Piston rings, e.g. associated with piston crown · CPC title

• F16J9/08

  with expansion obtained by pressure of the medium · CPC title