GAS DIRECT INJECTOR WITH REDUCED LEAKAGE
An injector has an inlet and an outlet and an armature tube having passage structure and having a distal end spaced from the outlet. The passage structure communicates with the inlet. A movable, magnetic armature is coupled to the armature tube. An electromagnetic coil is associated with a stator and with the armature. A first spring is constructed and arranged, when the coil is not activated, to bias the armature tube so that the distal end engages in a sealing manner with a first seat to limit leakage of the gaseous fuel from the outlet. A second valve is movable in a valve body. A second spring is constructed and arranged, when the coil is not activated, to bias the second valve so that a seating surface thereof engages a second seat to close the outlet.
The invention relates to a gas injector, where the gas could be natural gas (CNG or LNG), hydrogen or liquefied petroleum gas (LPG) or any mixtures of these gases and engine fuel systems and, more particularly, to a gas direct injector that reduces tip leakage.
BACKGROUNDWith gas injectors, tip leakage must be very low. In port gas injectors, the low leakage is achieved with an elastomeric seal. A problem with the direct gas injector is that the tip of the injector is too hot for an elastomeric seal at the tip. Conventional gas direct injectors use a metal-to-metal sealing solenoid valve. This metal-to-metal sealing will not meet leakage requirements.
Thus, there is a need to provide a low leakage gas direct injector using an additional elastomer sealing valve that is remote from the injector tip.
SUMMARYAn objective of the invention is to fulfill the need referred to above. In accordance with the principles of an embodiment, this objective is obtained by providing an injector having an inlet and an outlet for injecting gaseous fuels into an internal combustion engine. The injector includes an armature tube having passage structure and having a distal end spaced from the outlet. The passage structure communicates with the inlet. A movable, magnetic armature is coupled to the armature tube to define a first valve. A stator is spaced from the armature in a closed position of the injector, thereby defining a working air gap between the stator and the armature. An electromagnetic coil is associated with the stator and the armature. A first seat is associated with the distal end of the armature tube. A first spring is constructed and arranged, when the coil is not activated, to bias the armature tube so that the distal end engages in a sealing manner with the first seat close the passage structured and limit leakage of the gaseous fuel from the outlet. A valve body has an interior portion and a second seat at the outlet. A second valve is movable in the interior portion of the valve body. A second spring is constructed and arranged, when the coil is not activated, to bias the second valve so that a seating surface thereof engages the second seat to close the outlet. The first and second valves and the first and second springs are constructed and arranged such that when the coil is activated causing the armature and thus the armature tube to move with respect to the stator so that the distal end disengages from the first seat opening the passage structure and causing gaseous fuel to pass the first seat, pressure of the gaseous fuel causes the second valve to move against the bias of the second spring so that the seating surface disengages from the second seat to cause the gaseous fuel to exit the outlet.
In accordance with another aspect of an embodiment, a method limits leakage of a direct injector that has an inlet and an outlet for injecting gaseous fuels into an internal combustion engine. The injector also has an armature tube coupled to a movable armature, the armature tube having passage structure and having a distal end spaced from the outlet, the passage structure communicating with the inlet; a stator and a coil associated with the armature for causing movement of the armature and thus the armature tube upon energizing the coil; a first seat associated with the distal end of the armature tube; and a second valve movable in a valve body of the injector and with respect to a second seat. When the coil is not activated, the distal end of the armature tube is caused to engage in a sealing manner with the first seat to close the passage structured and limit leakage of the gaseous fuel from the outlet, and a seating surface of the second valve is caused to engage the second seat to close the outlet. When the coil is activated causing the armature and thus the armature tube to move with respect to the stator so that the distal end disengages from the first seat opening the passage structure and causing gaseous fuel to pass the first seat, the method ensures that pressure of the gaseous fuel causes the second valve to move so that the seating surface disengages from the second seat to cause the gaseous fuel to exit the outlet.
Other objects, features and characteristics of the present invention, as well as the methods of operation and the functions of the related elements of the structure, the combination of parts and economics of manufacture will become more apparent upon consideration of the following detailed description and appended claims with reference to the accompanying drawings, all of which form a part of this specification.
The invention will be better understood from the following detailed description of the preferred embodiments thereof, taken in conjunction with the accompanying drawings, wherein like reference numerals refer to like parts, in which:
With reference to
With reference to
As best shown in
Returning to
The passage 40 in the armature tube 28 and passage 38 in the member 36 communicate with the inlet 11 that is defined by an inlet tube assembly 50. The armature tube 28 also includes openings 52. The interior portion 30 and passages 38, 40 and openings 52 define passage structure, the function of which will be explained below. As shown in
When the coil 22 is activated (energized), in response to the magnetic field, the armature 16 moves the armature tube 28 in the direction A in
Thus, with reference to
Although the injectors 10, 10′ have been described for use with natural gas, hydrogen, LPG or any other gaseous fuel, the injectors can be used in any gaseous automotive platform. The injectors 10 and 10′ can fit into exiting packaging. Due to the valve group subassembly 13 and the magnetic group subassembly 14, the injectors 10, 10′ are modular.
The foregoing preferred embodiments have been shown and described for the purposes of illustrating the structural and functional principles of the present invention, as well as illustrating the methods of employing the preferred embodiments and are subject to change without departing from such principles. Therefore, this invention includes all modifications encompassed within the spirit of the following claims.
Claims
1. An injector having an inlet and an outlet for injecting gaseous fuels into an internal combustion engine, the injector comprising:
- an armature tube having passage structure and having a distal end spaced from the outlet, the passage structure communicating with the inlet,
- a movable, magnetic armature coupled to the armature tube to define a first valve,
- a stator spaced from the armature in a closed position of the injector, thereby defining a working air gap between the stator and the armature,
- an electromagnetic coil associated with the stator and the armature,
- a first seat associated with the distal end of the armature tube,
- a first spring constructed and arranged, when the coil is not activated, to bias the armature tube so that the distal end engages the first seat to close the passage structure and limit leakage of the gaseous fuel from the outlet,
- a valve body having an interior portion and a second seat at the outlet,
- a second valve movable in the interior portion of the valve body, and
- a second spring constructed and arranged, when the coil is not activated, to bias the second valve so that a seating surface thereof engages the second seat to close the outlet,
- wherein the first and second valves and the first and second springs are constructed and arranged such that when the coil is activated causing the armature and thus the armature tube to move with respect to the stator so that the distal end of the armature tube disengages from the first seat opening the passage structure and causing gaseous fuel to pass the first seat, pressure of the gaseous fuel causes the second valve to move against the bias of the second spring so that the seating surface disengages from the second seat to cause the gaseous fuel to exit the outlet, wherein the distal end of the armature tube includes an elastomer member constructed and arranged to engage the first seat in a sealing manner.
2. (canceled)
3. The injector of claim 1, wherein the first seat is annular having a central sealing portion, an outer sealing portion and flow passages there-through and located between the sealing portions such that 1) when the coil is not activated, the elastomer member of the armature tube engages the sealing portions and 2) when the coil is activated and the elastomer member disengages from the sealing portions, the gaseous fuel can pass through the flow passages.
4. The injector of claim 3, wherein the flow passages are slots extending circumferentially of the annular elastomer member.
5. The injector of claim 3, wherein an end surface of the armature tube includes an annular groove, with a portion of the elastomer member disposed in the groove.
6. The injector of claim 1, wherein the first seat is coupled to a back-up member that is fixed to a housing of the injector.
7. The injector of claim 1, wherein the second valve is located between the first valve and the outlet.
8. The injector of claim 1, wherein a distal end of the injector is constructed and arranged to be mounted for direct injection.
9. The injector of claim 1, further comprising a flange coupled to a distal end of the injector, with an O-ring associated with the flange so that the injector can be mounted for port injection.
10. The injector of claim 1, wherein, when the coil is activated, the second valve is constructed and arranged to move in a direction opposite the movement of the armature tube.
11. The injector of claim 1, in combination with the gaseous fuel, the gaseous fuel being natural gas, hydrogen, or LPG.
12. A method of limiting leakage of a direct injector, the injector comprising an inlet and an outlet for injecting gaseous fuels into an internal combustion engine, the injector further comprising an armature tube coupled to a movable armature to define a first valve, the armature tube having passage structure and having a distal end spaced from the outlet, the passage structure communicating with the inlet; a stator and a coil associated with the armature for causing movement of the armature and thus the armature tube upon energizing the coil; a first seat associated with the distal end of the armature tube; and a second valve movable within a valve body of the injector and with respect to a second seat, the method comprising the steps of:
- when the coil is not activated, causing the distal end of the armature tube to engage in a sealing manner with the first seat and close the passage structure to limit leakage of the gaseous fuel from the outlet, and causing a seating surface of the second valve to engage the second seat to close the outlet, wherein the first seat has a central sealing portion, an outer sealing portion and flow passages there-through that are located between the sealing portions, and
- when the coil is activated causing the armature and thus the armature tube to move with respect to the stator so that the distal end disengages from the first seat opening the passage structure and causing gaseous fuel to pass the first seat, ensuring that pressure of the gaseous fuel causes the second valve to move so that the seating surface disengages from the second seat to cause the gaseous fuel to exit the outlet.
13. The method of claim 12, wherein the distal end of the armature tube includes an elastomer member for sealing with the first seat.
14. The method of claim 13, wherein the step of causing at the distal end of the armature tube to engage with the first seat includes:
- using a spring to bias the armature tube so that the elastomer member engages the sealing portions and, when the coil is activated and the elastomer member disengages from the sealing portions, the gaseous fuel can pass through the flow passages.
15. The method of claim 12, wherein the step of causing a seating surface of the second valve to engage the second seat of the valve body includes:
- using a spring to bias the second valve so that the seating surface engages the second seat.
16. The method of claim 15, wherein the step of ensuring that pressure of the gaseous fuel causes the second valve to move includes:
- selecting a force of the spring so that a certain pressure of the fuel overcomes the force of the spring.
17. The method of claim 13, further comprising:
- limiting an exposure of the elastomer member to combustion temperatures by locating the second valve between the first valve and the outlet so that the elastomer member is spaced from the outlet.
18. The method of claim 12, wherein, when the coil is energized, the second valve moves by the pressure in a direction opposite the movement of the armature tube.
19. The method of claim 12, further comprising:
- configuring the injector so as to be mounted for direct injection into a combustion chamber of an engine.
20. The method of claim 12, wherein the gaseous fuel is natural gas, hydrogen, or LPG.
Type: Application
Filed: Mar 20, 2015
Publication Date: Sep 22, 2016
Inventors: Michael J. Hornby (Williamsburg, VA), Klaus Husslein (Regensburg), Harry Schüle (Neunburg), Christopher Heukenroth (Berlin), Wolfram Klemp (Berlin), Thomas Komischke (Berliln), Thomas Gerlach (Hamburg)
Application Number: 14/664,367