Piston design for splitting jets

Patent metadata

Field	Value
Publication number	US-10087882-B2
Application number	US-201615338643-A
Country	US
Kind code	B2
Filing date	Oct 31, 2016
Priority date	Oct 31, 2016
Publication date	Oct 2, 2018
Grant date	Oct 2, 2018

Abstract

A piston has a piston crown portion forming at least one arcuate indent in aligned fashion with a fuel jet discharged into a combustion chamber. Each arcuate event forms lobes, which separate the fuel jet into portions, or is tiered, to accommodate fuel jet portions being discharged into the combustion chamber at different times. Each lobe or tier includes an entry surface, a recirculation surface and a wall to separate it from adjacent lobes or tiers, respectively.

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, wherein the top surface of the crown portion 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; 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; a plurality of arcuate indents formed in the top surface of the crown portion, the plurality of arcuate indents being arranged to cover the crown portion in aligned relation with a plurality of nozzle openings formed in the nozzle tip of the fuel injector and along a respective fuel jet centerline, each of the plurality of arcuate indents including a flat entry surface and further including two or more lobes, each of the two or more lobes includes the flat 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 flat entry surface, and a wall extending generally in an axial direction and disposed radially along the recirculation surface; wherein each flat entry surface lies along a respective angled plane that is disposed at an acute angle relative to a plane of the top surface of the crown portion; wherein each flat entry surface has a generally triangular shape with curved edges that includes a central point disposed adjacent a piston surface center; wherein the flat entry surface extends away from the piston surface center in a radial direction along the respective angled plane; and wherein, during operation, a single fuel jet provided into each of the plurality of arcuate indents is separated into a plurality of fuel jet portions, each of the plurality of fuel jet portions corresponding to one of the two or more lobes.

2. The internal combustion engine of claim 1 , wherein each of the arcuate indents has a concave shape extending away from the plane of the top surface of the crown portion in a direction into a body of the piston, and wherein each of the plurality of arcuate indents presents flat, concave or convex surfaces, which directly or indirectly redirect a respective fuel jet provided into each of the plurality of the arcuate indents during operation of the internal combustion engine.

3. The internal combustion engine of claim 1 , wherein, opposite the central point of the top surface of the crown portion, the flat entry surface of each of the two or more lobes has a generally curved edge that is sickle-shaped, which forms a transition between the flat entry surface and the recirculation surface.

4. The internal combustion engine of claim 1 , wherein each recirculation surface forms a bottom-most portion of the corresponding one of the two or more lobes of each of the plurality of arcuate indents.

5. The internal combustion engine of claim 4 , wherein each recirculation surface has a concave shape that sweeps in the spiral direction radially outwardly from a center portion of the piston along a corresponding curved edge of the flat entry surface.

6. 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, wherein the top surface of the crown portion 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; 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; a plurality of arcuate indents formed in the top surface of the crown portion, the plurality of arcuate indents being arranged to cover the crown portion in aligned relation with a plurality of nozzle openings formed in the nozzle tip of the fuel injector and along a respective fuel jet centerline, each of the plurality of arcuate indents including two or more lobes, each of the two or more lobes 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; wherein each recirculation surface forms a bottom-most portion of the corresponding one of the two or more lobes of the arcuate indent and 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; and wherein, during operation, a single fuel jet provided into each of the plurality of arcuate indents is separated into a plurality of fuel jet portions, each of the plurality of fuel jet portions corresponding to one of the two or more lobes.

7. The internal combustion engine of claim 6 , wherein each of the plurality of arcuate indents has a concave shape extending away from the single plane in a direction into a body of the piston, and wherein the plurality of arcuate indents present flat, concave or convex surfaces, which directly or indirectly redirect the fuel jet provided into the plurality of arcuate indents during operation of the internal combustion engine.

8. The internal combustion engine of claim 6 , wherein each of the plurality of arcuate indents includes a flat entry surface.

9. The internal combustion engine of claim 8 , wherein the flat entry surface lies along an angled plane that is disposed at an acute angle relative to the single plane of the top surface of the crown portion.

10. The internal combustion engine of claim 9 , wherein each flat entry surface has a generally triangular shape with curved edges that includes a central point disposed adjacent a piston surface center, and wherein each flat entry surface extends away from the piston surface center in a radial direction along the angled plane.

11. The internal combustion engine of claim 9 , wherein, opposite a central point of the top surface of the crown portion, the flat entry surface of each of the two or more lobes has a generally curved edge that is sickle-shaped, which forms a transition between the flat entry surface and the recirculation surface.

12. 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 combu

Assignees

• Caterpillar Inc

Inventors

• John Bobby
• Anders Jonathan W

Classifications

• F02B23/0624

  Swirl flow · CPC title

• F02M61/14

  Arrangements of injectors with respect to engines; Mounting of injectors · CPC title

• F02F3/24

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

• F02F1/242

  Arrangement of spark plugs or injectors · CPC title

• F02F3/28 Primary

  Other pistons with specially-shaped head · CPC title