Internal combustion engine and method for its operation

Patent metadata

Field	Value
Publication number	US-10731544-B2
Application number	US-201816139289-A
Country	US
Kind code	B2
Filing date	Sep 24, 2018
Priority date	Sep 24, 2018
Publication date	Aug 4, 2020
Grant date	Aug 4, 2020

Abstract

In internal combustion engine, a fuel injector has a nozzle tip forming first and second pluralities of nozzle openings configured to inject respective pluralities of first and second fuel jets into a combustion chamber. The first fuel jets are directed between projections formed in a piston during a main injection, and the second fuel jets are directed towards the protrusions during a post injection. The protrusions are asymmetrical to redirect the first fuel jets.

First claim

I claim:

1. An internal combustion engine, comprising:
an engine block having a cylinder bore;
a cylinder head having a flame deck surface disposed at one end of the cylinder bore;
at least one intake valve associated with the cylinder head and configured to open and allow a flow of intake charge into 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, the crown portion including a piston bowl having a generally concave shape and extending within the crown portion and a wall, the wall extending peripherally around the piston;
a fuel injector having a nozzle tip disposed in fluid communication with the combustion chamber, the nozzle tip having a first plurality of nozzle openings configured to inject a plurality of first fuel jets into the combustion chamber, each of the plurality of first fuel jets being provided along a respective first fuel jet centerline;
a plurality of protrusions disposed in the piston bowl adjacent the wall, each of the plurality of protrusions including a first side surface and a second side surface, wherein each of the plurality of protrusions is disposed between two adjacent ones of the respective first fuel jet centerlines;
wherein the fuel injector nozzle tip has a second plurality of nozzle openings configured to inject a plurality of second fuel jets, each of the plurality of second fuel jets being provided along a respective second fuel jet centerline;
wherein each of the respective second fuel jet centerlines intersects a respective one of the plurality of protrusions;
wherein the fuel injector is configured and operates to provide the plurality of first fuel jets during a main injection event during a compression stroke and/or an expansion stroke; and
wherein the fuel injector is configured and operates to provide the plurality of second fuel jets during a post injection event during the compression stroke and/or the expansion stroke, which post injection event occurs after an initiation of the main injection event.

2. The internal combustion engine of claim 1 , wherein a number of the first plurality of nozzle openings matches a number of the plurality of protrusions.

3. The internal combustion engine of claim 1 , wherein a number of the second plurality of nozzle openings matches a number of the first plurality of nozzle openings.

4. The internal combustion engine of claim 1 , wherein the plurality of protrusions are each arranged at regular intervals along equally distributed radial axes along the top surface, each of the distributed radial axes being disposed at an angle that is between spray directions of adjacent ones of the first nozzle openings of the fuel injector such that each of the first fuel jets emanates in a radial direction between two adjacent ones of the equally distributed radial axes.

5. The internal combustion engine of claim 1 , wherein the plurality of protrusions are each arranged at regular intervals along equally distributed radial axes along the top surface, each of the equally distributed radial axes being aligned with one of the second plurality of nozzle openings of the fuel injector such that each of the second fuel jets emanates in a radial direction towards a corresponding protrusion of the plurality of protrusions.

6. The internal combustion engine of claim 1 , wherein the first plurality of nozzle openings are configured to inject the plurality of first fuel jets at a first angle relative to a longitudinal axis of the cylinder bore and the second plurality of nozzle openings are configured to inject the plurality second fuel jets at a second angle relative to the longitudinal axis of the cylinder bore, the first angle being different from the second angle.

7. A method of operating an internal combustion engine, the method comprising:
slidably disposing a piston within a cylinder bore, the piston including a crown portion extending below a top surface of a piston body, the crown portion including a bowl having a generally concave shape and extending within the crown portion and a wall, the wall extending peripherally around the piston body, wherein the crown portion includes a plurality of protrusions disposed in the bowl adjacent the wall, each of the plurality of protrusions including a first side surface and a second side surface, each of the plurality of protrusions lying along a respective radial axis;
providing a plurality of first fuel jets over a first time period during a compression and/or expansion stroke, each of the plurality of first fuel jets being provided between two adjacent ones of the respective radial axes; and
providing a plurality of second fuel jets over a second time period during the compression and/or expansion stroke, the second time period beginning after the first time period begins;
wherein each of the plurality of second fuel jets is provided in a direction that is between two adjacent ones of the first fuel jets.

8. The method of claim 7 , wherein each of the plurality of second fuel jets is provided in a direction towards one of the plurality of protrusions.

9. The method of claim 7 , wherein the plurality of first fuel jets represents a main injection event that delivers a majority of a fuel quantity required to carry out an expansion stroke.

10. The method of claim 9 , wherein the plurality of second fuel jets represents a post injection event that delivers a minority of the fuel quantity required to carry out the expansion stroke.

11. The method of claim 7 , wherein a number of the plurality of first fuel jets matches a number of the plurality of protrusions.

12. The method of claim 7 , wherein a number of the plurality of second fuel jets matches a number of the plurality of first fuel jets.

13. The method of claim 7 , wherein a number of the plurality of second fuel jets matches a number of the plurality of protrusions.

14. The method of claim 7 , wherein the first fuel jets are provided at a first angle relative to a longitudinal axis of the cylinder bore and the second fuel jets are provided at a second angle relative to the longitudinal axis of the cylinder bore, the first angle being different from the second angle.

15. A method for operating an internal combustion engine, comprising:
admitting a swirling intake charge mass into a combustion cylinder;
providing a plurality of first fuel jets into the combustion cylinder;
redirecting the plurality of first fuel jets within the combustion cylinder;
providing a plurality of second fuel jets into the combustion cylinder after beginning to provide the plurality of first fuel jets;
wherein the plurality of second fuel jets are each provided along a radial axis that is disposed between adjacent ones of the first fuel jets.

16. The method of claim 15 , wherein redirecting the plurality of first fuel jets is accomplished by:
defining the combustion cylinder at least partially by a crown portion of a reciprocable piston, the crown portion including a bowl having a plurality of protrusions disposed peripherally around the bowl; and
directing the plurality of first fuel jets along axes extending between adjacent ones of the protrusions.

17. The method of claim 16 , wherein providing the plurality of second fuel jets includes directing each of the plurality of second fuel jets towards one of the plurality of protrusions.

18. Th

Assignees

• Caterpillar Inc

Inventors

• Svensson Kenth I

Classifications

• F02B23/0678 Primary

  Unconventional, complex or non-rotationally symmetrical shapes of the combustion space, e.g. flower like, having special shapes related to the orientation of the fuel spray jets · CPC title

• F02D41/405

  with post injections · CPC title

• F02B23/0669

  having multiple fuel spray jets per injector nozzle · CPC title

• F02M61/182

  Discharge orifices being situated in different transversal planes with respect to valve member direction of movement · CPC title

• Y02T10/40

  Engine management systems · CPC title