Contaminant tolerant compressed natural gas injector and method of directing gaseous fuel therethrough

• US 20040011896A1
• Filed: 12/10/2002
• Published: 01/22/2004
• Est. Priority Date: 05/27/1998
• Status: Abandoned Application

• Current Assignee: Siemens Automotive Corporation (Siemens AG)
• Original Assignee: Siemens Automotive Corporation (Siemens AG)
• Inventors: Cohen, James H., Wright, Danny Orlen, Fochtman, James Paul
• Application Number:
  US10/315,262
• Publication Number:
  US 20040011896A1
• Time in Patent Office: Days
• US Class Current: 239/585.1
• CPC Class Codes: F02M 21/0215 Mixtures of gaseous fuels; Natural gas; Biogas; Mine gas; Landfill gas
• CPC Class Codes: F02M 21/0254 Electric actuators, e.g. solenoid or piezoelectric
• CPC Class Codes: F02M 21/0266 Hollow stem valves; Piston valves; Stems having a spherical tip
• CPC Class Codes: F02M 51/0625 characterised by arrangement of mobile armatures
• CPC Class Codes: F02M 51/0671 the armature having an elongated valve body attached thereto
• CPC Class Codes: F02M 61/12 characterised by the provision of guiding or centring means for valve bodies
• CPC Class Codes: Y02T 10/30 Use of alternative fuels, e.g. biofuels

Abstract

An electromagnetically actuable fuel injector for an internal combustion engine is disclosed having an outer housing, a fuel inlet connector positioned in the upper end portion of the outer housing for reception of fuel therein, and an armature having a valve needle attached thereto and positioned adjacent the fuel inlet connector and spaced therefrom by a working gap. The armature defines a generally elongated central opening to receive fuel flow from the fuel inlet connector and has valve needle attached thereto which interacts with a fixed valve having a fixed valve seat associated with the housing to selectively permit fuel to flow through a valve aperture associated with the fixed valve seat. The fuel inlet connector has a fuel outlet end facing a fuel inlet end of the armature and includes a plurality of radially extending raised pads separated by a corresponding plurality of radially extending recessed portions to reduce the contact area between the fuel inlet connector and the armature when the armature is moved upwardly, and to promote fuel flow transversely across the working gap therebetween to establish a first fuel flow path outside of the armature. The first fuel flow path prevents contaminants from accumulating in the working gap. The armature includes at least one first aperture extending through a wall portion thereof for receiving fuel flow from the generally elongated central opening and for directing the fuel flow to a second flow path toward the fixed valve seat. At least one-second aperture extends through a wall portion of the armature and extends at a generally acute angle relative to the longitudinal axis to establish a third fuel flow path toward the fixed valve seat. The size, orientation and numbers of the apertures can be varied to achieve predetermined flow conditions. A method of directing fuel through an injector is also disclosed although the fuel injector and method disclosed utilize gaseous fuels, all types of fuels are contemplated.

Claims

1. An electromagnetically operable fuel injector for a gaseous fuel injection system of an internal combustion engine, said injector having a generally longitudinal axis, which comprises:

a) a ferromagnetic core;

b) a magnetic coil at least partially surrounding the ferromagnetic core;

c) an armature magnetically coupled to said magnetic coil and being movably responsive to said magnetic coil, said armature actuating a valve closing element which interacts with a fixed valve seat of a fuel valve and being movable away from said fixed valve seat when said magnetic coil is excited, said armature having a generally elongated shape and a generally central opening for axial reception and passage of gaseous fuel from a fuel inlet connector positioned adjacent thereto, said fuel inlet connector and said armature being adapted to permit a first flow path of gaseous fuel between said armature and said magnetic coil as part of a path leading to said fuel valve; and

d) at least one first fuel flow aperture extending through a wall portion of said armature to define a second flow path of gaseous fuel as part of a path leading to said fuel valve.

2. The electromagnetically operable fuel injector according to Claim 1, wherein said armature defines at least one second aperture in a wall portion thereof to define a third flow path of gaseous fuel as part of a path leading to said fuel valve.

3. The electromagnetically operable fuel injector according to Claim 2, wherein said at least one-second aperture is oriented at a generally acute angle with respect to the longitudinal axis.

4. The electromagnetically operable fuel injector according to Claim 3, wherein said fuel inlet connector and said armature are spaced to define a working gap therebetween and are adapted to permit said first flow path of gaseous fuel within said working gap.

5. The electromagnetically operable fuel injector according to Claim 3, further comprising a valve body positioned downstream of said armature and having at least one aperture in a wall portion thereof for reception of fuel from at least two of said flow paths of gaseous fuel from said armature and said fuel inlet connector.

6. The electromagnetically operable fuel injector according to Claim 5, further comprising a valve body shell at least partially surrounding said armature and said valve body, said valve body shell defining a radial space with said armature for passage of said first flow path of gaseous fuel between said armature and said valve body shell.

7. The electromagnetically operable fuel injector according to Claim 6, wherein said fuel inlet connector is positioned above said armature and is spaced from said armature by a working gap, said fuel inlet connector defining a through passage for directing fuel toward said armature and said fixed valve seat.

8. The electromagnetically operable fuel injector according to Claim 7, wherein said fuel inlet connector comprises an upper end portion adapted for reception of gaseous fuel from a fuel source, and a lower end portion for discharging gaseous fuel, said lower end portion having a lower surface which faces an upper surface of said armature, said lower surface of said fuel inlet connector having a plurality of radially extending raised pads defined thereon, said pads having recessed portions therebetween to permit fuel to flow therethrough and across said working gap defined between said fuel inlet connector and said armature.

9. An electromagnetically operable fuel injector for a compressed natural gas fuel injection system of an internal combustion engine, said injector having a generally longitudinal axis, which comprises:

a) a ferromagnetic core;

b) a magnetic coil at least partially surrounding said ferromagnetic core;

c) an armature coupled to said magnetic coil and movably responsive to said magnetic coil, said armature having a first upper end face and a lower end portion;

d) a valve closing element connected to said lower end portion of said armature and interactive with a fixed valve seat to selectively permit fuel to pass through said valve seat as said valve closing element is moved to a valve open position by said armature;

e) a fuel inlet connector extending in a generally longitudinal direction above said armature and defining a path for fuel to enter said inlet connector and to be directed toward said armature, said fuel inlet connector having a lowermost end portion having a lowermost surface spaced above said armature to define a working gap through which said armature is movable; and

f) said armature having a fuel reception portion for receiving fuel directed from said fuel inlet connector, said armature further defining a generally axial fuel passage and at least a first fuel flow aperture extending through a wall portion thereof for directing fuel from said fuel inlet connector through said generally axial fuel passage and into said aperture toward said fixed valve seat for entry into an air intake manifold for the engine, said fuel flow aperture being oriented generally transverse to said longitudinal axis.

10. The electromagnetically operable fuel injector according to Claim 9, wherein said armature further defines at least a second fuel flow aperture extending through a lower portion thereof and oriented at an acute angle with said longitudinal axis, and positioned for directing fuel therethrough toward said fixed valve seat.

11. The electromagnetically operable fuel injector according to Claim 10, wherein said lowermost surface of said fuel inlet connector and said armature are adapted to permit gaseous fuel to flow across said working gap and between said armature and said magnetic coil whereby at least three fuel flow paths are permitted.

12. The electromagnetically operable fuel injector according to Claim 11, wherein said lowermost end portion of said fuel inlet connector has a generally chamfered configuration along the lowermost outer surface thereof.

13. The electromagnetically operable fuel injector according to Claim 12, wherein said generally chamfered portion of said fuel inlet connector has a generally arcuate cross-section.

14. The electromagnetically operable fuel injector according to Claim 13, wherein said valve closing element is a valve needle adapted for selective engagement and disengagement with said fixed valve seat.

15. The electromagnetically operable fuel injector according to Claim 14, wherein said valve needle is attached to said armature by crimped portions of said armature.

16. The electromagnetically operable fuel injector according to Claim 15, wherein a fuel filter is positioned at an upper end portion of said fuel inlet connector for filtering fuel prior to reception by said fuel inlet connector.

17. The electromagnetically operable valve according to Claim 16, wherein said fuel inlet connector includes a lower surface portion having a plurality of radially extending grooves defining a corresponding plurality of radially extending raised pads so as to reduce the effective surface area of said lower surface portion of said fuel inlet connector facing said armature to thereby permit the gaseous fuel to flow generally transversely in said working gap, said transverse fuel flow thereby preventing accumulation of contaminants in said working gap.

18. The electromagnetically operable fuel injector according to Claim 17, wherein said generally radially extending pads have a generally trapezoidal shape.

19. An electromagnetically operable fuel injector for a gaseous fuel injection system of an internal combustion engine, said injector having a generally longitudinal axis, which comprises:

a) a ferromagnetic core;

b) a magnetic coil at least partially surrounding the ferromagnetic core;

c) an armature magnetically coupled to said magnetic coil and being movably responsive to said magnetic coil, said armature actuating a valve closing element which interacts with a fixed valve seat of a fuel valve and being movable away from said fixed valve seat when said magnetic coil is excited, said armature having a generally elongated shape and a generally central opening for axial reception and passage of gaseous fuel from a fuel inlet connector positioned adjacent thereto, said fuel inlet connector having a lower surface portion having a continuous annular surface having a circular shape; and

d) at least one first fuel flow aperture extending through a wall portion of said armature for reception of gaseous fuel flowing from said inlet connector and for directing the gaseous fuel to a valve body at least partially surrounding said armature, said valve body having a generally elongated central opening for reception of substantially all of the gaseous fuel from said armature.

20. The electromagnetically operable fuel valve according to Claim 19, wherein said at least one first fuel flow aperture extending through a wall portion of said armature is oriented at a generally acute angle with respect to said generally longitudinal axis.

21. An electromagnetically operable fuel injector for an internal combustion engine, said injector defining a generally longitudinal axis, which comprises:

a) an outer housing;

b) a fuel inlet connector positioned in the upper end portion of said outer housing, said fuel inlet connector having an uppermost end portion for reception of fuel therein and a lowermost end portion for discharge of fuel therefrom;

c) an armature positioned below said fuel inlet connector and defining a generally axial elongated central opening to receive fuel flow from said fuel inlet connector, said armature having an uppermost end portion positioned below said lowermost end portion of said fuel inlet connector to define a working gap, and a lowermost end portion having a valve closing element positioned thereon for interaction with a fixed valve having a fixed valve seat associated with said housing to selectively permit fuel to flow through a valve aperture associated with said fixed valve seat when said armature is selectively moved upwardly toward said fuel inlet connector;

d) said fuel inlet connector having a lowermost end portion having a lowermost surface which faces said uppermost end portion of said armature, said lowermost end portion of said fuel inlet connector having a plurality of radially extending grooves separated by a corresponding plurality of radially extending raised pads to reduce the effective contact surface area between said inlet connector and said armature and to permit fuel to flow from said fuel inlet connector across said working gap;

e) a magnetic coil system for moving said armature and said valve closing element away from said fixed valve seat and toward said fuel inlet connector when said magnetic coil system is energized so as to permit fuel to flow through said fixed valve seat;

f) a resilient device to bias said armature and said valve closing element to move toward said fixed valve seat when said magnetic coil system is deenergized;

g) at least one first aperture extending through a wall portion of said armature for receiving fuel flow from said fuel inlet connector and directing said fuel flow from said generally elongated central opening of said armature toward said fixed valve seat, said at least one aperture being generally transverse to the longitudinal axis; and

h) at least one second aperture extending through a wall portion of said armature for receiving fuel flow from said fuel inlet connector and directing said fuel flow toward said fixed valve seat, said second aperture being oriented at a generally acute angle relative to the longitudinal axis for directing fuel from said generally central opening outwardly of said armature and downwardly toward said fixed valve seat.

22. The electromagnetically operable fuel injector according to Claim 21, wherein said valve closing element is a generally elongated valve needle having a spherically shaped end portion and configured and adapted to engage a frusto-conically shaped fixed valve seat to close said valve, and movable therefrom to open said valve to permit fuel to pass therethrough toward the intake manifold of the internal combination engine.

23. The electromagnetically operable fuel injector according to Claim 22, wherein said valve needle is connected to the lower end portion of said armature by crimped portions.

24. The electromagnetically operable fuel injector according to Claim 23, wherein said resilient device is a coil spring in engagement at one end with said fuel inlet connector and at the other end with said armature to bias said armature downwardly toward said valve seat.

25. The electromagnetically operable fuel injector according to Claim 24, wherein said armature includes at least two of said first apertures extending through wall portions thereof and generally transverse to the longitudinal axis for receiving fuel from said generally axial elongated central opening.

26. The electromagnetically operable fuel injector according to Claim 25, wherein said armature defines a plurality of said first apertures for receiving fuel from said generally axial elongated central opening.

27. The electromagnetically operable fuel injector according to Claim 26, wherein said armature defines at least a plurality of said second apertures, each said second apertures extending at a generally acute angle to the longitudinal axis to receive fuel from said generally central opening.

28. A method of directing gaseous fuel through air electromagnetically operable fuel injector for a fuel system of an internal combustion engine, said injector having a generally longitudinal axis, and including a fuel inlet end portion and a fuel outlet end portion, a fuel inlet connector positioned at said fuel inlet end portion and having a fuel inlet end portion and a fuel outlet end portion, an armature positioned adjacent said fuel outlet end portion of said fuel inlet connector and having a generally central elongated opening for reception of fuel from said fuel inlet connector, said armature being spaced from said fuel inlet connector to define a working gap to permit movement of said armature toward and away from said fuel inlet connector to selectively open and close a fuel valve to permit gaseous fuel to pass therethrough to an air intake manifold, comprising:

a) directing the gaseous fuel to pass axially through said fuel inlet connector;

b) directing the gaseous fuel to pass from said fuel inlet connector to said generally elongated central opening of said armature in an axial direction toward said fuel valve;

c) directing at least a portion of the fuel flow from said fuel inlet connector to said armature to flow generally transversely across said working gap; and

d) diverting at least a portion of the flow of gaseous fuel passing through said armature to flow in a direction away from said axial direction.

29. The method according to Claim 28, wherein said step of directing the gaseous fuel passing through said armature to flow in a direction away from the axial direction is accomplished by directing the gaseous fuel through at least one first aperture provided in a wall portion of said armature.

30. The method according to Claim 29, wherein said aperture in said wall portion of said armature extends generally transverse to said axial direction.

31. The method according to Claim 30, wherein a lower end portion of said fuel inlet connector facing an upper end portion of said armature is configured to permit said gaseous fuel to flow from said fuel inlet connector to be directed transversely across said working gap.

32. The method according to Claim 31, wherein at least a portion of the gaseous fuel flowing in said armature is permitted to pass through at least one second aperture in a lower wall portion thereof;

said at least one second aperture extending at an acute angle to said longitudinal axis, whereby at least three separate fuel flow paths are established.

33. The method according to Claim 32, wherein said injector comprises a magnetic coil system having a magnetic coil, and said armature is magnetically coupled to said magnetic coil system to cause said armature to move toward and away from said fuel inlet connector, at least one of said fuel flow paths being located between said armature and said magnetic coil.

34. A method of directing compressed natural gas through an electromagnetically operable fuel injector for a fuel system of an internal combustion engine, said injector having a generally longitudinal axis, and including a fuel inlet end portion and a fuel outlet end portion, a fuel inlet connector positioned at said fuel inlet end portion, and an armature positioned adjacent said fuel inlet connector and said fuel outlet end portion of said injector, said armature being spaced from said fuel inlet connector to define a working gap to permit movement of said armature toward and away from said fuel inlet connector, said armature having a generally axial fuel passage opening and having attached thereto a valve needle having an end portion adapted to selectively disengage and engage a fuel valve to open and close said valve to permit gaseous fuel to pass therethrough, comprising:

a) directing the gaseous fuel through said fuel inlet connector;

b) directing the gaseous fuel to pass from said fuel inlet connector to said fuel passage opening of said armature in an axial direction toward said fuel valve;

c) directing at least a portion of the flow of gaseous fuel passing through said armature to flow through at least one first aperture in a wall portion of said armature, said aperture extending in a direction generally transverse to said axial direction;

d) directing at least a portion of the flow of gaseous fuel passing through said armature to flow in a direction at an acute angle to said axial direction through at least one second aperture in a lower wall portion of said armature; and

e) directing at least a portion of the flow of gaseous fuel passing from said fuel inlet connector to said armature to flow generally transverse to said axial direction across said working gap between said fuel inlet connector and said armature so as to establish at least three separate fuel flow paths between said fuel inlet portion and said fuel outlet portion of said injector.

35. The method according to Claim 34, wherein said fuel inlet connector includes a plurality of adjacent raised pads on a lowermost end portion thereof, said raised pads being respectively spaced by adjacent recessed portions to permit the flow of gaseous fuel through said working gap when said armature moves toward said fuel inlet connector to thereby open said fuel valve.

36. The method according to Claim 35, wherein said at least one first and second apertures in said armature are from about 1 to about 2.0 mm in diameter.

37. The method according to Claim 36, wherein predetermined numbers of said first and second apertures are provided and the diameters thereof are predetermined to establish a predetermined number of fuel flow paths and volumetric flow rates thereof.

38. A method of directing fuel through an electromagnetically operable fuel injector for a fuel system of an internal combustion engine, said injector having a generally longitudinal axis, and including a fuel inlet end portion and a fuel outlet end portion, a fuel inlet connector positioned at said fuel inlet end portion, and an armature positioned adjacent said fuel inlet connector and said fuel outlet end portion of said injector, said armature being spaced from said fuel inlet connector to define a working gap to permit movement of said armature toward and away from said fuel inlet connector, said armature having a generally axial fuel passage opening for reception of fuel from said fuel inlet connector, and having attached thereto a valve needle having an end portion adapted to selectively disengage and engage a fuel valve to open and close said valve to permit fuel to pass therethrough, comprising:

a) directing the fuel through said fuel inlet connector;

b) directing the fuel to pass from said fuel inlet connector to said fuel passage opening of said armature in an axial direction toward said fuel valve;

c) directing at least a portion of the flow of fuel passing from said fuel inlet connector to said armature to flow generally transverse to said axial direction across said working gap between said fuel inlet connector and said armature so as to establish at least one separate fuel flow path outside of said armature.

d) directing at least a portion of the flow of fuel passing through said armature to flow at least along a second flow path through at least one first aperture in a wall portion of said armature, said aperture extending in a direction generally transverse to said axial direction; and

e) directing at least a portion of the flow of fuel passing through said armature to flow at least along a third flow path in a direction at an acute angle to said axial direction through at least one second aperture in a lower wall portion of said armature.