Internal combustion engine with split pilot injection

Patent metadata

Field	Value
Publication number	US-10041402-B2
Application number	US-201715489994-A
Country	US
Kind code	B2
Filing date	Apr 18, 2017
Priority date	May 12, 2016
Publication date	Aug 7, 2018
Grant date	Aug 7, 2018

Abstract

An internal combustion engine includes a housing defining an internal cavity, an inner body sealingly moving within the internal cavity for defining at least one combustion chamber of variable volume, a pilot subchamber in communication with the at least one working chamber, an ignition element in communication with the pilot subchamber, a main injector communicating with the at least one combustion chamber, and a pilot injector having a tip in communication with the pilot subchamber. The tip of the pilot injector includes at least a first injection hole defining a first spray direction and a second injection hole defining a second spray direction different from the first spray direction. The first spray direction extends toward the communication between the pilot subchamber and the at least one working chamber. A method of performing combustion in an internal combustion engine is also discussed.

First claim

The invention claimed is:

1. An internal combustion engine comprising:
a housing defining an internal cavity;
an inner body sealingly moving within the internal cavity for defining at least one working chamber of variable volume;
a pilot subchamber in communication with the at least one working chamber;
an ignition element in communication with the pilot subchamber;
a main injector communicating with the at least one working chamber; and
a pilot injector having a tip in communication with the pilot subchamber, the tip of the pilot injector including at least one first injection hole and at least one second injection hole, the at least one first injection hole configured to form a first spray having a first spray direction, the at least one second injection hole configured to form a second spray having a second spray direction different from the first spray direction, the first spray direction extending toward a communication the pilot subchamber and the at least one working chamber, the at least one first injection hole and the at least one second injection hole being configured such that first spray includes a greater volume of fuel than the second spray.

2. The internal combustion engine as defined in claim 1 , wherein the second spray direction extends away from the communication between the pilot subchamber and the at least one working chamber.

3. The internal combustion engine as defined in claim 1 , wherein the second spray direction extends toward the ignition element.

4. The internal combustion engine as defined in claim 1 , wherein the pilot subchamber is defined in an insert received in a wall of the housing, the pilot subchamber communicating with the at least one working chamber through an opening defined in the insert, and wherein the first spray has a central axis extending through the opening.

5. The internal combustion engine as defined in claim 4 , wherein the second spray has a central axis intersecting a wall of the pilot subchamber at a location spaced apart from the opening.

6. The internal combustion engine as defined in claim 1 , wherein the first spray direction extends along a central longitudinal axis of the pilot injector.

7. The internal combustion engine as defined in claim 1 , wherein the at least one first injection hole has a greater cross-sectional area than that of the at least one second injection hole.

8. The internal combustion engine as defined in claim 1 , wherein the internal combustion engine is a rotary engine, the inner body is a rotor having three apex portions mounted for eccentric revolutions within the internal cavity, the internal cavity having an epitrochoid shape with two lobes.

9. The internal combustion engine as defined in claim 1 , wherein the at least one first injection hole and the at least one second injection hole are relatively sized such the first spray includes at least 62.5% of a pilot quantity of fuel injected by the pilot injector.

10. An internal combustion engine comprising:
a housing defining an internal cavity;
an inner body sealingly moving within the internal cavity for defining at least one working chamber of variable volume;
a pilot subchamber in communication with the at least one working chamber;
an ignition element in communication with the pilot subchamber;
a main injector in communication with the at least one working chamber; and
a pilot injector having a tip including at least first and second injection holes in communication with the pilot subchamber, the first injection hole configured to form a first spray having a first spray direction, the pilot injector having a central longitudinal axis aligned with a communication between the pilot subchamber and the at least one working chamber, the central longitudinal axis intersecting the first injection hole and the first spray direction corresponding to the central longitudinal axis, the second injection hole being spaced from the central longitudinal axis.

11. The internal combustion engine as defined in claim 10 , wherein the second spray direction has a central axis intersecting a wall of the pilot subchamber at a location spaced apart from the communication between the pilot subchamber and the at least one working chamber.

12. The internal combustion engine as defined in claim 11 , wherein the spray direction of the second injection hole extends toward the ignition element.

13. The internal combustion engine as defined in claim 10 , wherein the pilot subchamber is defined in an insert received in a wall of the housing, the pilot subchamber communicating with the at least one working chamber through an opening defined in the insert, and wherein the central longitudinal axis extends through the opening.

14. The internal combustion engine as defined in claim 10 , wherein the first injection hole has a greater cross-sectional area than that of the second injection hole such that first spray includes a greater volume of fuel than the second spray.

15. The internal combustion engine as defined in claim 10 , wherein the internal combustion engine is a rotary engine, the inner body is a rotor having three apex portions mounted for eccentric revolutions within the internal cavity, the internal cavity having an epitrochoid shape with two lobes.

16. A method of performing combustion in an internal combustion engine, the method comprising:
simultaneously injecting first and second sprays of a pilot quantity of fuel in a pilot subchamber with a pilot injector, the first spray being directed toward a communication between the pilot subchamber and a working chamber of the internal combustion engine, the second spray being directed away from the first spray;
igniting the fuel within the pilot subchamber;
injecting a main quantity of fuel in the working chamber with a main injector; and
circulating the ignited fuel from the pilot subchamber into the working chamber to ignite the main quantity of fuel in the working chamber.

17. The method as defined in claim 16 , wherein igniting the fuel is performed with an ignition element, and wherein the second spray is directed toward the ignition element.

18. The method as defined in claim 16 , wherein igniting the fuel is performed with two spaced apart ignition elements, and wherein the second spray is directed between the two ignition elements.

19. The method as defined in claim 16 , wherein the first spray includes a greater volume of fuel than the second spray.

20. The method as defined in claim 16 , wherein the first spray is directed along a central longitudinal axis of the pilot injector.

21. The method as defined in claim 16 , wherein the internal combustion engine is a rotary engine, the inner body is a rotor having three apex portions mounted for eccentric revolutions within the internal cavity, the internal cavity having an epitrochoid shape with two lobes.

Assignees

• Pratt & Whitney Canada

Inventors

• Schulz Edwin
• Lanktree Michael
• Thomassin Jean

Classifications

• F01C21/106

  with a radial surface, e.g. cam rings · CPC title

• F02B19/12

  with positive ignition (engines with non-timed positive ignition, and with incandescent chambers F02B9/08) · CPC title

• F01C1/344

  with vanes reciprocating with respect to the inner member · CPC title

• F02B19/1019

  with only one pre-combustion chamber (F02B19/1004 take precedence) · CPC title

• F01C1/22

  of internal-axis type with equidirectional movement of co-operating members at the points of engagement, or with one of the co-operating members being stationary, the inner member having more teeth or tooth- equivalents than the outer member · CPC title