Piston design for flow re-direction

Patent metadata

Field	Value
Publication number	US-9995203-B2
Application number	US-201615335904-A
Country	US
Kind code	B2
Filing date	Oct 27, 2016
Priority date	Oct 27, 2016
Publication date	Jun 12, 2018
Grant date	Jun 12, 2018

Abstract

An internal combustion engine includes an engine block having a cylinder bore and a cylinder head having a flame deck surface disposed at one end of the cylinder bore. A piston connected to a rotatable crankshaft and configured to reciprocate within the cylinder bore has a piston crown portion facing the flame deck surface such that a combustion chamber is defined within the cylinder bore and between the piston crown and the flame deck surface. A fuel injector having a nozzle tip disposed in fluid communication with the combustion chamber has at least one nozzle opening configured to inject a fuel jet into the combustion chamber along a fuel jet centerline. At least one arcuate indent is formed in the top surface in aligned fashion with the fuel jet and including an entry surface, a recirculation surface and a wall.

First claim

We claim:

1. An internal combustion engine, comprising:
an engine block having at least one cylinder bore;
a cylinder head having a flame deck surface disposed at one end of the cylinder bore;
a piston connected to a rotatable crankshaft and configured to reciprocate within the cylinder bore, the piston having a crown portion facing the flame deck surface such that a combustion chamber is defined within the cylinder bore and between a top surface of the crown portion and the flame deck surface;
a fuel injector having a nozzle tip disposed in fluid communication with the combustion chamber, the nozzle tip having at least one nozzle opening configured to inject a fuel jet into the combustion chamber and along a fuel jet centerline;
at least one arcuate indent formed in the top surface, the at least one arcuate indent being aligned with the fuel jet centerline and including an entry surface extending from a central portion of the piston, a recirculation surface having a concave shape and extending along a spiral direction adjacent the entry surface, and a wall extending generally in an axial direction and disposed radially along the recirculation surface.

2. The internal combustion engine of claim 1 , wherein the top surface has a generally circular shape that is defined within a circular periphery and has a generally flat shape that extends along a single plane that is nominally disposed in perpendicular relation to a centerline axis of the cylinder bore.

3. The internal combustion engine of claim 2 , wherein the piston forms a plurality of arcuate indents arranged to cover the crown portion in aligned relation with a plurality of nozzle openings formed in the nozzle tip of the fuel injector.

4. The internal combustion engine of claim 2 , wherein the at least one arcuate indent has a concave shape extending away from the plane in a direction into a body of the piston, and wherein the at least one arcuate indent presents flat, concave or convex surfaces, which directly or indirectly redirect the fuel jet provided into the arcuate indent during operation of the internal combustion engine.

5. The internal combustion engine of claim 2 , wherein the at least one arcuate indent includes a flat, entry surface.

6. The internal combustion engine of claim 5 , wherein the entry surface lies along an angled plane that is disposed at an acute angle relative to the plane of the top surface.

7. The internal combustion engine of claim 6 , wherein the entry surface has a generally triangular shape with curved edges that includes a central point disposed adjacent a piston surface center, and wherein the entry surface extends away from the piston surface center in a radial direction along the angled plane to provide a cambered or pitched surface that, during operation, engages and contacts a respective fuel jet to direct it along the plane and into the arcuate indent.

8. The internal combustion engine of claim 6 , wherein, opposite a central point of the top surface, the entry surface has a generally curved edge that is sickle-shaped, which forms a transition between the entry surface and the recirculation surface.

9. The internal combustion engine of claim 1 , wherein recirculation surface forms a bottom-most portion of the arcuate indent.

10. The internal combustion engine of claim 9 , wherein the recirculation surface has a concave shape that sweeps in the spiral direction radially outwardly from a center portion of the piston along a curved edge of the entry surface.

11. The internal combustion engine of claim 10 , wherein a cross section available for fuel jet redirection of the recirculation surface is maximum along a middle portion thereof and decreases in both radial directions inwardly and outwardly with respect to the piston.

12. The internal combustion engine of claim 1 , wherein the wall has a variable height that is minimum along radially inward and outward ends of the wall, and is maximum along a middle portion thereof.

13. The internal combustion engine of claim 12 , wherein the wall presents a top edge having a generally curved shape and a bottom edge that follows an external edge of the recirculation surface.

14. The internal combustion engine of claim 1 , wherein at an interface or rim of the at least one arcuate indent with respect to the top surface is disposed a convex transition.

15. The internal combustion engine of claim 1 , further comprising a depressed surface that bows away from a plane of the crown portion.

16. The internal combustion engine of claim 1 , further comprising a plurality of arcuate indents arranged symmetrically around the piston, wherein a transition between adjacent arcuate indents in a radially outward region is truncated to create a segmented circular periphery that surrounds a central depression defined around a piston surface center.

17. The internal combustion engine of claim 1 , further comprising a plurality of arcuate indents arranged symmetrically around the piston, wherein a transition between adjacent arcuate indents in a radially outward region forms sharp angles.

18. The internal combustion engine of claim 1 , further comprising a recessed upper edge that creates an empty space around a top, outer periphery of the piston, which opens up space above a region along an outer peripheral cylindrical surface of the piston that is disposed above an upper seal ring of the piston and occupies a cylindrical space between the piston and an inner surface of the cylinder bore.

19. The internal combustion engine of claim 18 , further comprising a frusto-conical surface extending at an acute angle between a top edge of the outer peripheral cylindrical surface of the crown portion and an outer periphery of the top surface.

20. The internal combustion engine of claim 19 , wherein the frusto-conical surface occupies a height in an axial direction along a centerline of the crown portion.

Assignees

• Caterpillar Inc

Inventors

• John Bobby
• Anders Jonathan W
• Delvecchio Kerry A

Classifications

• F02B23/0669

  having multiple fuel spray jets per injector nozzle · CPC title

• F02B23/0651 Primary

  the fuel spray impinging on reflecting surfaces or being specially guided throughout the combustion space · CPC title

• F02F3/24

  having means for guiding gases in cylinders, e.g. for guiding scavenging charge in two-stroke engines · CPC title

• Y02T10/12

  Improving ICE efficiencies · CPC title