Piston for a heat engine, heat engine comprising such a piston, and methods

Patent metadata

Field	Value
Publication number	US-11098674-B2
Application number	US-201816477232-A
Country	US
Kind code	B2
Filing date	Jan 10, 2018
Priority date	Jan 11, 2017
Publication date	Aug 24, 2021
Grant date	Aug 24, 2021

Abstract

Various implementations include a combustion engine piston, including a skirt in a counter-part and including a first contact area of the piston in the counter-part, a head which extends transverse to a central axis, and a ring carrier which comprises at least two lands and at least two grooves for receiving the rings, including a first land adjoining the head and a second land situated between the first land and the skirt, wherein the lands include at least one contact land having a diameter greater than a minimum diameter of the skirt to form a second contact area of the piston in the counter-part, and wherein at least one contact land comprises a friction-reducing surface coating, formed at least on a radial sector covering an angle of at least 30 degrees, and up to on a single sector covering an angle of 360 degrees.

First claim

The invention claimed is:

1. A combustion engine piston, comprising:
a skirt for guiding the piston in translation along a central axis in a counter-part and including a first contact area of the piston in the counter-part,
a head which extends transverse to the central axis and is arrangeable to be in contact with the combustion gases, and
a ring carrier which comprises at least two lands and at least two grooves for receiving rings, including a first land adjoining the head and a second land situated between the first land and the skirt,
wherein the lands include at least one contact land having a diameter greater than a minimum diameter of the skirt to form a second contact area of the piston in the counter-part,
wherein the at least one contact land comprises a friction-reducing surface coating formed at least on a radial sector covering an angle of at least 30 degrees, and up to on a single sector covering an angle of 360 degrees, and
wherein the diameter of the contact land is considered without the coating, and the diameter of the skirt is considered without bore.

2. The piston according to claim 1 , wherein at least one contact land has a diameter greater than an average diameter of the skirt.

3. The piston according to claim 1 , wherein the piston is a short piston, having a diameter and a height smaller than the diameter.

4. The piston according to claim 1 , wherein the base material of the piston is steel.

5. The piston according to claim 1 , wherein the friction-reducing surface coating is made from DLC-type amorphous carbon a-C:H.

6. The piston according to claim 1 , wherein the friction-reducing surface coating is made from DLC-type amorphous carbon ta-C.

7. The piston according to claim 1 , wherein the at least one contact land includes at least one sublayer formed below the friction-reducing surface coating.

8. The piston according to claim 1 , wherein the second land has a diameter larger than the first land.

9. The piston according to claim 1 , wherein among the lands of the ring carrier, only the at least one contact land-include a friction-reducing surface coating.

10. The piston according to claim 1 , wherein the ring carrier comprises a single contact land.

11. The piston according to claim 10 , wherein in that the single contact land is the second land.

12. The piston according to claim 1 , wherein the ring carrier comprises two contact lands.

13. The piston according to claim 12 , wherein the two contact lands are the second land and a third land.

14. The piston according to claim 12 , wherein the two contact lands are the first land and the second land.

15. A heat engine, comprising:
a piston according to claim 1 ; and
a counter-part receiving the piston.

16. The heat engine according to claim 15 , wherein the counter-part includes a friction-reducing surface coating made from amorphous carbon of the DLC type.

17. A method for coating a piston according to claim 1 , wherein the method comprises the following steps:
a step for positioning a mask on the piston, and
a step for localized deposition of a friction-reducing surface coating through the mask, at least on the at least one contact land.

18. A method for implementing a heat engine according to claim 15 , wherein the skirt and the at least one contact land including the friction-reducing surface coating make up the contact areas of the piston in the counter-part.

Assignees

• Hydromecanique & Frottement

Inventors

• Prost Fabrice
• Heau Christophe
• Montelimard Romain

Classifications

• F02F3/0084 Primary

  the pistons being constructed from specific materials · CPC title

• F16J9/00 Primary

  Piston-rings {, e.g. non-metallic piston-rings}, seats therefor; Ring sealings of similar construction (other sealings between pistons and cylinders F16J3/06, F16J15/16 {; manufacture of piston-rings B23P15/06, B23P15/08}; tools for mounting or removing piston-rings or the like B25B; piston sealing arrangements on brake master cylinders B60T11/236 {; sealing provided on pump pistons F04B53/143}) · CPC title

• F02F3/10 Primary

  having surface coverings (F02F3/02 takes precedence) · CPC title

• F16J9/26

  characterised by the use of particular materials · CPC title

• F16J1/02

  Bearing surfaces · CPC title