GAS INJECTOR HAVING REDUCED WEAR

Abstract

A gas injector for injecting a gaseous fuel. The gas injector includes a solenoid actuator having an armature, an internal pole and a coil; a closing element, which unblocks and seals a gas path at a valve seat, the armature being connected to the closing element; a sealed lubricant chamber, which is filled with a lubricant, and in which the armature is situated, the lubricant ensuring lubrication of the armature; and a flexible sealing element, which seals the lubricant chamber with respect to the gas path, a damping device being situated in the lubricant chamber.

Claims

1-10. (canceled)

11. A gas injector for injecting a gaseous fuel, comprising: a solenoid actuator having an armature, an internal pole, and a coil; a closing element, which unblocks and seals a gas path at a valve seat, the armature being connected to the closing element; a sealed lubricant chamber, which is filled with a lubricant, and in which the armature is situated, the lubricant ensuring lubrication of the armature; and a flexible sealing element, which seals the lubricant chamber with respect to the gas path.

12. The gas injector as recited in claim 11, further comprising: a damping device configured to decelerate the closing element during a resetting operation of the gas injector from an open into a closed state, and situated in the lubricant chamber.

13. The gas injector as recited in claim 12, wherein the damping device includes a damping pin and an elastic damping element; and, the damping pin and the elastic damping element are configured to be brought into operative connection with the closing element and/or the armature, during the resetting operation.

14. The gas injector as recited in claim 13, wherein the damping pin is guided in a damping guide element in the lubricant chamber.

15. The gas injector as recited in claim 14, wherein in the closed state of the injector, a first axial gap between the damping guide element and the damping pin is smaller than a second axial gap between the armature and the internal pole.

16. The gas injector as recited in claim 11, wherein the sealed lubricant chamber is filled completely or partially with lubricant, the lubricant including oil or gasoline or diesel, or grease.

17. The gas injector as recited in claim 11, wherein the flexible sealing element is a bellows, the bellows being a metal bellows or a diaphragm.

18. The gas injector as recited in claim 11, wherein: a gas path for the gaseous fuel runs in a region between a valve housing and a solenoid housing of the solenoid actuator; or the gas path of the gaseous fuel runs through a region of the solenoid actuator in which the coil is situated.

19. The gas injector as recited in claim 11, wherein the gas injector is an injector that opens outwards.

20. The gas injector as recited in claim 11, wherein a mean diameter of the flexible sealing element is equal to a diameter of the valve seat on the valve body, at which the closing element unblocks and seals the gas path.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In the following, exemplary embodiments of the present invention are described in detail with reference to the figures.

[0018] FIG. 1 shows a schematic sectional view of a gas injector according to a first exemplary embodiment of the present invention.

[0019] FIG. 2 shows a schematic, enlarged part-sectional view of the gas injector of FIG. 1.

[0020] FIG. 3 shows a further schematic, enlarged part-sectional view of the gas injector of FIG. 1.

[0021] FIG. 4 shows a schematic part-sectional view of a gas injector according to a second exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0022] In the following, a gas injector 1 according to a first preferred exemplary embodiment of the present invention is described in detail with reference to FIGS. 1 through 3.

[0023] As is apparent from FIG. 1, in order to introduce a gaseous fuel, gas injector 1 includes a solenoid actuator 2, which moves a closing element 3 from a closed state into an open state; in this exemplary embodiment, the closing element being a valve needle opening outwards. In this context, FIGS. 1 through 3 show the closed state of the gas injector.

[0024] Solenoid actuator 2 includes an armature 20, which abuts closing element 3 with the aid of an armature pin 24. In addition, solenoid actuator 2 includes an internal pole 21, a coil 22 and a solenoid housing 23, which secures a magnetic yoke of the solenoid actuator.

[0025] Furthermore, gas injector 1 includes a main member 7 having a connecting pipe 70, through which the gaseous fuel is fed. In this context, a valve housing 8, in which solenoid actuator 2 is situated, is fixed to main member 7. Valve housing 8 is followed by a valve body 9, at whose free end a valve seat 90 is provided, in which closing element 3 unblocks and seals a passage for the gaseous fuel.

[0026] An electrical terminal 13, which is run through main member 7 to solenoid actuator 2, is represented schematically in FIGS. 1 through 3.

[0027] A retaining member 12 is provided, in order to fix internal pole 21 to valve body 9.

[0028] Reference numeral 10 denotes a restoring element for closing element 3, for moving it back again into the closed state shown in FIG. 1, after an opening operation.

[0029] In addition, a gas stream in the form of a gas path 14 through gas injector 1 is represented in FIG. 1. In this context, the gas stream begins at the connecting pipe and is then rerouted by 90° into an annular space 80 between valve housing 8 and main member 7. In this case, gas stream 14 goes further past an outer region of solenoid actuator 2, through a filter 11 in the region at closing element 3, to valve seat 90. Accordingly, in this connection, openings, which are not shown in the figures, are provided in the specific components.

[0030] Then, upon the opening of gas injector 1, the gaseous fuel flows past the periphery of solenoid actuator 2 and past open sealing seat 90 into a combustion chamber of an internal combustion engine, which is indicated in FIG. 1 by arrow A.

[0031] Thus, closing element 3 unblocks a gas path at valve seat 90 and seals it. For guidance, a first guide region 31 and a second guide region 32 are between closing element 3 and valve body 9, as is apparent in the detail from FIG. 2.

[0032] In addition, gas injector 1 includes a sealed lubricant chamber 4. Lubricant chamber 4 may be seen in the detail from FIGS. 2 and 3. Sealed lubricant chamber 4 is filled completely or partially with a lubricant.

[0033] As is apparent from FIG. 2, lubricant chamber 4 is bounded by main member 7, solenoid housing 23, internal pole 21, and a flexible sealing element 5 in the form of a bellows. In this context, flexible sealing element 5 provides sealing at closing element 3. Consequently, a first end of flexible sealing element 5 is fixed in position at a spring collar 16, which supports a restoring element 10 for closing element 3, and a second end of the flexible sealing element is fixed in position at a sleeve-shaped ring 15. In this context, flexible sealing element 5 compensates for the movement of closing element 3 occurring in axial direction X-X of the injector.

[0034] As may be seen in detail from FIGS. 2 and 3, the armature pin 24 having armature 20 fixed to it is situated in sealed lubricant chamber 4. Since lubricant chamber 4 is filled with a lubricant, for example, a liquid fuel such as gasoline or diesel, or a grease or the like, armature 20 is lubricated continuously. In this manner, the problem of missing lubrication of the moving parts, which occurs in the related art in the case of gaseous fuels, may be compensated for.

[0035] As is apparent from FIG. 2, a filling duct 63 for filling the sealed lubricant chamber 4 is formed in main member 7. Filling duct 63 is sealed in a fluid-tight manner with the aid of a sealing ball 64.

[0036] In addition, a damping device 6 is situated in sealed lubricant chamber 4. Damping device 6 includes a damping pin 60, a damping spring 61, and a damping guide element 62. Damping guide element 62 is used for guiding damping pin 60 and is situated at an inner circumference of solenoid housing 23 (cf. FIGS. 2 and 3).

[0037] In this context, damping pin 60 is operatively connected to the armature via armature pin 24.

[0038] In this case, damping device 6 has the task of decelerating closing element 3, together with armature 20, during a closing operation of gas injector 1. In this context, the damping is accomplished, on one hand, by the damping spring force from damping spring 61 at damping pin 60, as well as by hydraulic adhesion at an axial contact surface 65 between damping pin 60 and stationary damping guide element 62 (cf. FIG. 3) upon lift-off of damping pin 60 from axial contact surface 65.

[0039] During the resetting of closing element 3, it is additionally decelerated by the friction in damping guide element 62, into which part of armature pin 24 also projects. Furthermore, the masses to be accelerated and the displacement of the lubricant in sealed lubricant chamber 4 result in additional damping during the closing operation.

[0040] In the closed state, an axial gap C is provided between armature 20 and internal pole 21, as is apparent from FIG. 2. An axial gap B is provided between damping pin 60 and damping guide element 62. Axial gap C between armature 20 and internal pole 21 is preferably in a range of 0.05 to 3 mm and is, particularly preferably, 0.2 to 0.5 mm. When there is flow through coil 22, armature 20 is then drawn towards internal pole 21, through which closing element 3 in brought into the open state via armature pin 24, which allows gaseous fuel to flow out into the combustion chamber. It should be pointed out that, in order to reduce magnetic leakage flux, in particular, armature pin 24 and/or sleeve-shaped ring 15 are made of non-magnetizable materials.

[0041] In this context, axial gap B between damping pin 60 and damping guide element 62 is smaller than gap C between armature 20 and internal pole 21, and during the opening operation, it is closed by the spring force of damping spring 61, as well. Gap B is preferably 1% to 90% of gap C. During the resetting operation, this produces the hydraulic adhesion of damping pin 60 to damping guide element 62.

[0042] With that, the gas injector 1 shown in FIGS. 1 through 3 is pressure-balanced. This means that closing element 3 is connected to flexible sealing element 5 via spring collar 16; the flexible sealing element 5 implemented as a metal bellows having a mean diameter D1, which is equal to a diameter D2 on valve seat 90, at which closing element 3 produces a seal on valve body 9. Due to this, there is no pressure force on closing element 3, which means that a magnetic force, which is necessary to open closing element 3, may be kept quite small and is, in particular, independent of a pressure of the gaseous fuel.

[0043] It is noted that instead of the bellows, e.g., a diaphragm or a tube or the like may also be used as a flexible sealing element 5.

[0044] Consequently, gas injector 1 may generate decreased wear on the moving parts, in particular, on valve seat 90, armature 20, and in armature pin 24. In addition, heat conduction through sealed lubricant chamber 4 out of solenoid actuator 2 may be improved markedly, using a liquid lubricant.

[0045] FIG. 4 shows a gas injector 1 according to a second exemplary embodiment of the present invention. The same or functionally equivalent parts are designated as in the first exemplary embodiment.

[0046] As is apparent from FIG. 4, the construction of gas injector 1 is fundamentally the same as that of the first exemplary embodiment. However, in contrast to it, a gas path 14 is routed differently in the region of solenoid actuator 2. In this connection, the gas path 14 in the second exemplary embodiment goes through the coil space at the solenoid actuator 2, in which coil 22 is situated. In this instance, gas path 14 leads through openings in pot magnet 25. Due to this, a valve housing may be dispensed with. In this context, the electrical terminal 13 in the form of a contact pin is insulated from main member 7. In addition, a first guide region 31 of closing element 3 is provided at a circumference of spring collar 16. Accordingly, spring collar 16 includes, in this context, transit openings for gas path 14. Lubricant chamber 4 is encapsulated in accordance with the first exemplary embodiment and provides lubrication to armature 20 during opening and closing operations of gas injector 1.

[0047] In all other respects, this exemplary embodiment corresponds to the first exemplary embodiment, so that reference is made to the description supplied there.