Piston for internal combustion engine

• US RE46,806 E1
• Filed: 03/25/2016
• Issued: 04/24/2018
• Est. Priority Date: 03/17/2011
• Status: Active Grant

• Current Assignee: Cummins Intellectual Property, Inc. (Cummins Incorporated)
• Original Assignee: Cummins Intellectual Property, Inc. (Cummins Incorporated)
• Inventors: Venugopal, Rishikesh, Stanton, Donald W., Ranganath, Bhargav, Bodin, Thomas
• Primary Examiner(s): DOERRLER, WILLIAM CHARLES
• Application Number:
  US15/081,441
• Time in Patent Office: 760 Days
• Field of Search: 1231936, 1231931
• CPC Class Codes: F02B 2275/14 Direct injection into combustion chamber
• CPC Class Codes: F02B 23/0651 the fuel spray impinging on reflecting surfaces or being specially guided throughout the combustion space
• CPC Class Codes: F02B 23/0669 having multiple fuel spray jets per injector nozzle
• CPC Class Codes: F02B 23/0693 the combustion space consisting of step-wise widened multiple zones of different depth
• CPC Class Codes: F02B 23/0696 W-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 wall
• CPC Class Codes: Y02T 10/125 Combustion chambers and charge mixing enhancing inside the combustion chamber

Abstract

A piston and an engine are provided that includes various precise configuration parameters, including dimensions, shape and/or relative positioning of combustion chamber features. More particularly, configuration parameters for a piston crown and a piston bowl located within the piston crown are provided. The piston bowl configuration results in a combustion process that yields decreased heat transfer to a cylinder head of the internal combustion engine as well as reduced NOx emissions.

Claims

1. An internal combustion engine, comprising:

an engine body;

a cylinder head attached to the engine body;

a combustion chamber positioned between the cylinder head and the engine body; and

a piston, including a piston crown that forms a portion of the combustion chamber, located in the engine body, the piston crown including a central axis,

a plurality of valve pockets arranged about the periphery of the piston crown in a plane perpendicular to the central axis,

an uppermost surface portion, and

a piston bowl positioned radially inward from the valve pockets, the piston bowl including;

a compound radius including a radius R1, radius R1 including a center of radius at a radial distance L1 from the central axis, radius R1 connected to and extending inwardly from the valve pockets to form a smooth transition between the valve pockets and the piston bowl;

a frustoconical outer floor portion connected to the compound radius, the frustoconical outer floor portion extending a distance L4 from the compound radius at an angle of to a plane perpendicular to the central axis;

an annular outer bowl portion including a radius R5; and

a spray-targeting feature positioned between the annular outer bowl portion and the frustoconical outer floor portion and including a radius R3 with a center of radius located at an axial distance H3 from the valve pockets,

wherein each of the valve pockets includes a rolled edge extending between the valve pocket and the uppermost surface portion, the rolled edge including a radius to form a smooth transition between the valve pocket and the uppermost surface portion;

wherein a ratio L4/R3 is in the range of 0.2 to 3.0.

2. The internal combustion engine of claim 1, wherein a ratio L4/R3 is in the range of 0.2 to 3.0.

3. The internal combustion engine of claim 2 1, wherein a ratio of H3/L1 is in the range of 0.15 to 0.3.

4. The internal combustion engine of claim 3, wherein α

1 is less than 60 degrees.

5. The internal combustion engine of claim 1, wherein a ratio of H3/L1 is in the range of 0.15 to 0.3.

6. The internal combustion engine of claim 5, wherein α

1 is less than 60 degrees.

7. The internal combustion engine of claim 1, wherein α

1 is less than 60 degrees.

8. The internal combustion engine of claim 1, the piston bowl further including a ski jump feature located radially inward from the annular outer bowl portion, the ski jump feature tangentially connected to the annular outer bowl portion and including a radius R4.

9. The internal combustion engine of claim 8, wherein a ratio R5/R4 is in the range of 2.5 to 5.0.

10. The internal combustion engine of claim 9, wherein a ratio L4/R3 is in the range of 0.2 to 3.0.

11. The internal combustion engine of claim 10, wherein a ratio of H3/L1 is in the range of 0.15 to 0.3.

12. The internal combustion engine of claim 11, wherein α

1 is less than 60 degrees.

13. The internal combustion engine of claim 9, wherein a ratio of H3/L1 is in the range of 0.15 to 0.3.

14. The internal combustion engine of claim 13, wherein α

1 is less than 60 degrees.

15. The internal combustion engine of claim 9, wherein α

1 is less than 60 degrees.

16. An internal combustion engine, comprising:

an engine body;

a cylinder head attached to the engine body;

a combustion chamber positioned between the cylinder head and the engine body; and

a piston, including a piston crown that forms a portion of the combustion chamber, located in the engine body, the piston crown including a central axis, an uppermost surface portion, a plurality of valve pockets arranged about the periphery of the piston crown in a plane perpendicular to the central axis, and a piston bowl positioned radially inward from the valve pockets, the piston bowl including;

a compound radius including a radius R1, radius R1 including a center of radius at a radial distance L1 from the central axis, radius R1 connected to and extending inwardly from the valve pockets to form a smooth transition between the valve pockets and the piston bowl;

a frustoconical outer floor portion connected to the compound radius, the frustoconical outer floor portion extending a distance L4 from the compound radius at an angle α

1 to a plane perpendicular to the central axis;

an annular outer bowl portion; and

a spray-targeting feature positioned between the annular outer bowl portion and the frustoconical outer floor portion and including a radius R3 with a center of radius located at an axial distance H3 from the end surface, each of the valve pockets including a rolled edge extending between the valve pocket and the uppermost surface portion, the rolled edge including a radius to form a smooth transition between the valve pocket and the uppermost surface portion;

wherein a ratio L4/R3 is in the range of 0.2 to 3.0 and a ratio H3/L1 is in the range of 0.15 to 0.3.

17. The internal combustion engine of claim 16, wherein α

1 is less than 60 degrees.

18. An internal combustion engine, comprising:

an engine body;

a cylinder head attached to the engine body;

a combustion chamber positioned between the cylinder head and the engine body; and

a piston, including a piston crown that forms a portion of the combustion chamber, located in the engine body, the piston crown including a central axis, an uppermost surface portion, a plurality of valve pockets arranged about the periphery of the piston crown in a plane perpendicular to the central axis, and a piston bowl positioned radially inward from the valve pockets, the piston bowl including;

a compound radius connected to and extending inwardly from the valve pockets to form a smooth transition between the valve pockets and the piston bowl;

a frustoconical outer floor portion connected to the compound radius, the frustoconical outer floor portion extending from the compound radius at an angle α

1 to a plane perpendicular to the central axis;

an annular outer bowl portion including a radius R5;

a spray-targeting feature positioned between the annular outer bowl portion and the frustoconical outer floor portion; and

a ski jump feature positioned between the annular outer bowl portion and the central axis and connected to the angular outer bowl portion, the ski jump feature including a radius R4,

each of the valve pockets including a rolled edge extending between the valve pocket and the uppermost surface portion, the rolled edge including a radius to form a smooth transition between the valve pocket and the uppermost surface portion;

wherein a ratio R5/R4 is in the range of 2.5 to 5.0.

19. The internal combustion engine of claim 18, wherein angle α

1 is less than 60 degrees.

20. The internal combustion engine of claim 19, wherein the frustoconical outer floor portion extends radially outward a distance L4 at an angle α

1 and the spray-targeting feature has a radius R3 and a ratio L4/R3 is in the range of 0.2 to 3.0.

21. A piston, comprising:

a piston crown including a central axis,

a plurality of valve pockets arranged about the periphery of the piston crown in a plane perpendicular to the central axis,

an uppermost surface portion, and

a piston bowl positioned radially inward from the valve pockets, the piston bowl including;

a compound radius including a radius R1, radius R1 including a center of radius at a radial distance L1 from the central axis, radius R1 connected to and extending inwardly from the valve pockets to form a smooth transition between the valve pockets and the piston bowl;

a frustoconical outer floor portion connected to the compound radius, the frustoconical outer floor portion extending a distance L4 from the compound radius at an angle α

1 to a plane perpendicular to the central axis;

an annular outer bowl portion including a radius R5; and

a spray-targeting feature positioned between the annular outer bowl portion and the frustoconical outer floor portion and including a radius R3 with a center of radius located at an axial distance H3 from the valve pockets,

wherein each of the valve pockets includes a rolled edge extending between the valve pocket and the uppermost surface portion, the rolled edge including a radius to form a smooth transition between the valve pocket and the uppermost surface portion;

wherein a ratio of H3/L1 is in the range of 0.15 to 0.3.

22. The piston of claim 21, wherein a ratio L4/R3 is in the range of 0.2 to 3.0.

23. The piston of claim 21, wherein α

1 is less than 60 degrees.

24. The piston of claim 21, the piston bowl further including a ski jump feature located radially inward from the annular outer bowl portion, the ski jump feature tangentially connected to the annular outer bowl portion and including a radius R4.

25. A piston, comprising:

a piston crown including a central axis, an uppermost surface portion,

a plurality of valve pockets arranged about the periphery of the piston crown in a plane perpendicular to the central axis, and

a piston bowl positioned radially inward from the valve pockets, the piston bowl including;

a compound radius including a radius R1, radius R1 including a center of radius at a radial distance L1 from the central axis, radius R1 connected to and extending inwardly from the valve pockets to form a smooth transition between the valve pockets and the piston bowl;

a frustoconical outer floor portion connected to the compound radius, the frustoconical outer floor portion extending a distance L4 from the compound radius at an angle α

1 to a plane perpendicular to the central axis;

an annular outer bowl portion; and

a spray-targeting feature positioned between the annular outer bowl portion and the frustoconical outer floor portion and including a radius R3 with a center of radius located at an axial distance H3 from the end surface, each of the valve pockets including a rolled edge extending between the valve pocket and the uppermost surface portion, the rolled edge including a radius to form a smooth transition between the valve pocket and the uppermost surface portion;

wherein a ratio L4/R3 is in the range of 0.2 to 3.0 and a ratio H3/L1 is in the range of 0.15 to 0.3.

26. The piston of claim 25, wherein α

1 is less than 60 degrees.

27. A piston, comprising:

a piston crown including a central axis, an uppermost surface portion,

a plurality of valve pockets arranged about the periphery of the piston crown in a plane perpendicular to the central axis, and

a piston bowl positioned radially inward from the valve pockets, the piston bowl including;

a compound radius connected to and extending inwardly from the valve pockets to form a smooth transition between the valve pockets and the piston bowl;

a frustoconical outer floor portion connected to the compound radius, the frustoconical outer floor portion extending from the compound radius at an angle α

1 to a plane perpendicular to the central axis;

an annular outer bowl portion including a radius R5;

a spray-targeting feature positioned between the annular outer bowl portion and the frustoconical outer floor portion; and

a ski jump feature positioned between the annular outer bowl portion and the central axis and connected to the annular outer bowl portion, the ski jump feature including a radius R4,

each of the valve pockets including a rolled edge extending between the valve pocket and the uppermost surface portion, the rolled edge including a radius to form a smooth transition between the valve pocket and the uppermost surface portion;

wherein a ratio R5/R4 is in the range of 2.5 to 5.0.

28. The piston of claim 27, wherein angle α

1 is less than 60 degrees.

29. The piston of claim 28, wherein the frustoconical outer floor portion

extends radially outward a distance L4 at an angle α

1 and the spray-targeting feature has a radius R3 and a ratio L4/R3 is in the range of 0.2 to 3.0.

30. A piston, comprising:

a piston crown including a central axis,

a plurality of valve pockets arranged about the periphery of the piston crown in a plane perpendicular to the central axis,

an uppermost surface portion, and

a piston bowl positioned radially inward from the valve pockets, the piston bowl including;

a compound radius including a radius R1, radius R1 including a center of radius at a radial distance L1 from the central axis, radius R1 connected to and extending inwardly from the valve pockets to form a smooth transition between the valve pockets and the piston bowl;

a frustoconical outer floor portion connected to the compound radius, the frustoconical outer floor portion extending a distance L4 from the compound radius at an angle α

1 to a plane perpendicular to the central axis;

an annular outer bowl portion including a radius R5;

a spray-targeting feature positioned between the annular outer bowl portion and the frustoconical outer floor portion and including a radius R3 with a center of radius located at an axial distance H3 from the valve pockets; and

a frustoconical segment positioned between the spray-targeting feature and the annular outer bowl portion to prevent an undercut in the piston bowl;

wherein each of the valve pockets includes a rolled edge extending between the valve pocket and the uppermost surface portion, the rolled edge including a radius to form a smooth transition between the valve pocket and the uppermost surface portion.