Combustion chamber for a direct-injection supercharged combustion engine

Patent metadata

Field	Value
Publication number	US-9284879-B2
Application number	US-80944908-A
Country	US
Kind code	B2
Filing date	Dec 15, 2008
Priority date	Dec 19, 2007
Publication date	Mar 15, 2016
Grant date	Mar 15, 2016

Abstract

A piston for an internal combustion engine, including a body configured to collaborate with walls of a cylinder of axis of revolution C in which the piston is configured to slide along the axis C. The piston includes a transverse face including a central pip, a peripheral ring, and a bowl of axis of revolution B extending from the central pip towards the peripheral ring to which it connects at a lip. The bowl includes, in substantial vertical alignment with the lip, a torus in profile, of maximum radius capable of guiding fuel injected under the lip in a region of a re-entrant zone towards the central pip. The tip of the pip lying on the axis of revolution B of the bowl rises to a height that is a distance of between 4.8 mm and 5.5 mm, or equal to 5.4 mm, below the level of the peripheral ring.

First claim

The invention claimed is:

1. A piston for an internal combustion engine, comprising:
a body laterally delimited by a skirt configured to collaborate with walls of a cylinder of axis of revolution (C) in which the piston is configured to slide along the axis (C), the piston comprising a transverse face which comprises a central pip, a peripheral crown ring, and a bowl of axis of revolution (B) with a maximum depth (P), the bowl extending from the central pip toward the peripheral crown ring to which it is connected at a lip with a thickness (Ep),
the bowl comprising a conical portion and, substantially in vertical alignment with the lip, a torus in profile, or half-dome shaped, with a radius (Rt),
wherein the torus is situated at a distance (Db/2) from the axis of revolution (B) of the bowl, and the torus is configured to guide a fuel injected under the lip in a reentrance zone (R) toward the central pip,
wherein the conical portion is between the central pip and the torus in profile,
wherein a top of the pip situated on the axis of revolution (B) of the bowl rises up to a height that is a distance (Dt) of between 4.8 mm and 5.5 mm below the height of the peripheral crown ring, wherein the entire surface of the lip is parallel to the bowl axis of revolution, and wherein a distance between the lip and the axis (B) is less than a distance between the axis (B) and the peripheral crown ring,
wherein a distance (Db) is between 52.5 mm and 56 mm, and wherein a ratio of the distance (Db) over the maximum depth (P) of the bowl is between 3.6 and 4.3.

2. The piston for an internal combustion engine as claimed in claim 1 , wherein the central pip slopes toward the torus by an angle (A), measured from the axis of revolution (B) of the bowl in the geometric direction, of between 62.5° and 65°.

3. The piston as claimed in claim 1 , wherein the bowl is centered in the cylinder, the axis of revolution (B) of the bowl coinciding with the axis of revolution (C) of the cylinder.

4. The piston as claimed in claim 1 , wherein the thickness (Ep) of the lip is between 3 mm and 4.2 mm.

5. The piston as claimed in claim 1 , wherein a maximum radius of curvature (Rt) of the torus is between 5 mm and 6 mm.

6. The piston as claimed in claim 1 , wherein the lip is situated a distance (De/2) from the axis of revolution (B) of the bowl, the distance (De) being between 49 mm and 51.5 mm.

7. The piston as claimed in claim 1 , wherein the difference in distances, with respect to the axis of revolution of the bowl, of the end of the crown ring (De/2) and of the end of the torus (Db/2) is substantially equal to 2 mm.

8. The piston as claimed in claim 1 , wherein the maximum depth (P) of the bowl is between 13 mm and 14.5 mm.

9. An internal combustion engine of diesel type, comprising at least one piston as claimed in claim 1 .

10. The piston as claimed in claim 1 , wherein the distance (Dt) is equal to 5.4 mm.

11. The piston as claimed in claim 1 , wherein the angle (A) is substantially equal to 64.6°.

12. The piston as claimed in claim 1 , wherein the thickness (Ep) is substantially equal to 3.8 mm.

13. The piston as claimed in claim 1 , wherein the maximum radius of curvature (Rt) of the torus is substantially equal to 5.2 mm.

14. The piston as claimed in claim 1 , wherein the distance (De) is substantially equal to 50 mm.

15. The piston as claimed in claim 1 , wherein the distance (Db) is substantially equal to 54 mm.

16. The piston as claimed in claim 1 , wherein the maximum depth (P) of the bowl is substantially equal to 14 mm.

17. The piston as claimed in claim 1 , wherein the thickness Ep is less than the distance Dt.

18. The piston as claimed in claim 5 , wherein the difference in distances, with respect to the axis of revolution of the bowl, of the end of the crown ring (De/2) and of the end of the torus (Db/2) is at most equal to a maximum radius of curvature (Rt) of the torus.

19. The piston as claimed in claim 1 , wherein the axis of revolution of the bowl is offset from the axis of revolution of the cylinder.

20. The piston as claimed in claim 19 , wherein the axis of revolution of the bowl is offset from the axis of revolution of the cylinder by less than 3 mm.

Assignees

• Dingreville Mickael
• Lavoisier Frederic
• Lechere Frederic
• Renault Sas

Inventors

• Dingreville Mickael
• Lavoisier Frederic
• Lechere Frederic

Classifications

• Y02T10/12

  Improving ICE efficiencies · CPC title

• Y02T10/125

  Cross-Sectional Technologies · mapped topic

• F02B23/0672 Primary

  Omega-piston bowl, i.e. the combustion space having a central projection pointing towards the cylinder head and the surrounding wall being inclined towards the cylinder center axis (the surrounding wall being exactly vertical F02B23/0696) · CPC title