Fuel injection spray patterns for opposed-piston engines

• US 20120073541A1
• Filed: 08/15/2011
• Published: 03/29/2012
• Est. Priority Date: 08/16/2010
• Status: Active Grant

• Current Assignee: Achates Power, Inc.
• Original Assignee: Achates Power, Inc.
• Inventors: Fuqua, Kevin B., Redon, Fabien G., Shen, Huixian, Wahl, Michael H.
• Granted Patent: US 8,820,294 B2
• Time in Patent Office: Days
• US Class Current: 123/301
• CPC Class Codes: F01B 7/02 with oppositely reciprocating pistons
• CPC Class Codes: F01B 7/08 with side rods
• CPC Class Codes: F01B 7/12 using rockers and connecting-rods
• CPC Class Codes: F02B 2275/48 Tumble motion in gas movement in cylinder
• CPC Class Codes: F02B 23/0621 Squish flow
• CPC Class Codes: F02B 23/0624 Swirl flow
• CPC Class Codes: F02B 23/063 the combustion space in the piston interacting fluid dynamically with the cylinder head, the injector body or the cylinder wall F02B23/04 takes precedence
• CPC Class Codes: F02B 23/0633 the combustion space being almost completely enclosed in the piston, i.e. having a small inlet in comparison to its volume
• CPC Class Codes: F02B 23/0645 Details related to the fuel injector or the fuel spray
• 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 23/0663 having multiple injectors per combustion chamber
• CPC Class Codes: F02B 23/0675 the combustion space being substantially spherical, hemispherical, ellipsoid or parabolic
• CPC Class Codes: F02B 23/0678 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 Class Codes: F02B 75/04 Engines with variable distances between pistons at top dead-centre positions and cylinder heads
• CPC Class Codes: F02B 75/28 Engines with two or more pistons reciprocating within same cylinder or within essentially coaxial cylinders arranged oppositely relative to main shaft F02B75/24
• CPC Class Codes: F02B 75/282 the pistons having equal strokes
• CPC Class Codes: F02B 75/32 Engines characterised by connections between pistons and main shafts and not specific to preceding main groups
• CPC Class Codes: F02M 61/14 Arrangements of injectors with respect to engines; Mounting of injectors
• CPC Class Codes: F02M 61/1806 characterised by the arrangement of discharge orifices, e.g. orientation or size
• CPC Class Codes: F16C 33/04 Brasses; Bushes; Linings
• CPC Class Codes: Y02T 10/12 : Improving ICE efficiencies

Abstract

A combustion chamber for an opposed-piston engine includes a squish zone defined between circumferential peripheral areas of opposing end surfaces of the pistons, a cavity defined by one or more bowls in the end surfaces, and at least one injection port that extends radially through the squish zone into the cavity. The cavity has a cross-sectional shape that imposes a tumbling motion on air flowing from the squish zone into the cavity. Opposing spray patterns of fuel are injected into the combustion chamber. In some aspects, the opposing spray patterns are injected along a major axis of the combustion chamber.

Claims

1. A method for operating an internal combustion engine including at least one cylinder with longitudinally-separated exhaust and intake ports, a pair of pistons disposed in opposition to one another in a bore of the cylinder, and a combustion chamber defined in the bore between end surfaces of the pistons, in which charge air is admitted into the bore from the intake port as the pistons move from respective bottom dead center positions in the bore, a tumble component is added to the motion of the air in the combustion chamber, and spray patterns of fuel are injected into the combustion chamber in opposing radial directions of the cylinder.

2. The method of claim 1, wherein the tumble component is added to the motion of the air as the pistons approach top dead center positions in the bore.

3. The method of claim 2, in which each spray pattern includes a plurality of plumes disposed in an array with respect to an axis of injection.

4. The method of claim 3, in which the spray patterns are rotationally oriented so as to orient the plumes of the spray patterns in opposition.

5. The method of claim 3, in which the spray patterns are rotationally oriented so that the plumes of the spray patterns are interdigitated.

6. The method of claim 1, wherein the charge air is swirled as it is admitted into the bore and the tumble component is added to a swirling motion of the air as the pistons approach top dead center positions in the bore.

7. The method of claim 6, in which each spray pattern includes a plurality of plumes disposed in an array with respect to an axis of injection.

8. The method of claim 7, in which the spray patterns are rotationally oriented so as to orient the plumes of the spray patterns in opposition.

9. The method of claim 7, in which the spray patterns are rotationally oriented so that the plumes of the spray patterns are interdigitated.

10. A method for operating an internal combustion engine including at least one cylinder with longitudinally-separated exhaust and intake ports, and a pair of pistons disposed in opposition to one another in a bore of the cylinder, by admitting air into the bore through the intake port as the pistons move from respective bottom dead center positions in the bore, causing a tumbling motion in the charge of air between opposing end surfaces of the pistons as the pistons move toward respective top dead center positions in the bore, and side-injecting opposing spray patterns of fuel into the charge air between the opposing end faces.

11. The method of claim 10, including moving the opposing bowls on facing end surfaces of the pistons together to define a combustion chamber having an elongated ellipsoidal shape.

12. The method of claim 11, in which injecting a charge of fuel into the charge of air includes injecting the fuel along a major axis of the combustion chamber.

13. The method of claim 11, in which each spray pattern includes a plurality of plumes disposed in an array with respect to an axis of injection.

14. The method of claim 13, in which the spray patterns are rotationally oriented so as to orient the plumes of the spray patterns in opposition.

15. The method of claim 13, in which the spray patterns are rotationally oriented so that the plumes of the spray patterns are interdigitated.

16. The method of claim 10, in which a swirling motion is imposed on the air admitted into the bore.

17. The method of claim 16, including moving the opposing bowls on facing end surfaces of the pistons together to define a combustion chamber having an elongated ellipsoidal shape having a major axis.

18. The method of claim 17, in which injecting a charge of fuel into the charge of air includes injecting the fuel along the major axis.

19. The method of claim 18, in which each spray pattern includes a plurality of plumes disposed in an array with respect to an axis of injection.

20. The method of claim 19, in which the spray patterns are rotationally oriented so as to orient the plumes of the spray patterns in opposition.

21. The method of claim 19, in which the spray patterns are rotationally oriented so that the plumes of the spray patterns are interdigitated.

22. A method for operating an internal combustion engine including at least one cylinder with longitudinally-separated exhaust and intake ports, and a pair of pistons disposed in opposition for reciprocating in a bore of the cylinder, by forming a combustion chamber having an elongated ellipsoidal shape between the end surfaces of the pistons as the pistons move toward respective top dead center positions in the bore, providing squish flows of charge air into the combustion chamber in directions that are skewed with respect to a major axis of the elongated ellipsoidal shape, generating at least one tumbling motion of charge air in the combustion chamber in response to the squish flows and swirling charge air, and injecting opposing spray patterns of fuel into the combustion chamber.

23. The method of claim 22, in which injecting opposing spray patterns of fuel into the combustion chamber includes injecting the spray patterns of fuel along the major axis.

24. The method of claim 23, in which each spray, pattern includes a plurality of plumes disposed in an array with respect to an axis of injection.

25. The method of claim 24, in which the spray patterns are rotationally oriented so as to orient the plumes of the spray patterns in opposition.

26. The method of claim 25, in which the plumes include four plumes.

27. The method of claim 25, in which generating at least one tumbling motion includes generating a first tumbling motion about a major axis and generating a second tumbling motion about an axis orthogonal to the major axis.

28. The method of claim 24, in which the spray patterns are rotationally oriented so that the plumes of the spray patterns are interdigitated.

29. The method of claim 28, in which the plumes include four plumes.

30. The method of claim 28, in which generating at least one tumbling motion includes generating a first tumbling motion about a major axis and generating a second tumbling motion about an axis orthogonal to the major axis.

31. The method of claim 24, in which the spray patterns are rotationally oriented in a range between an orientation in which the plumes of the spray patterns in opposition and an orientation in which the plumes of the spray patterns are interdigitated.