CN109973252B

CN109973252B - Gas injector with improved blow-in characteristics

Info

Publication number: CN109973252B
Application number: CN201811404373.XA
Authority: CN
Inventors: E·奥克伦特; A·克劳斯; F·米勒
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2017-11-23
Filing date: 2018-11-23
Publication date: 2022-09-23
Anticipated expiration: 2038-11-23
Also published as: CN109973252A; DE102017220911A1

Abstract

The invention relates to a gas injector for injecting a gaseous medium, in particular a gaseous fuel, comprising: a closing element (2) for releasing and closing at least one blow-in opening (11), wherein the at least one blow-in opening (11) has a first through-going cross-section (A1) in a first plane (E1) perpendicular to an axial direction (X-X) of the gas injector, wherein a sealing seat (15) is arranged on the blow-in opening (11); -an actuator (3) for actuating the closing element (2), and-a valve member having at least one first through opening (12a,12b) for the passage of the gaseous fuel, wherein said at least one first through opening (12a,12b) has a second through cross-section (a2) in a second plane (E2) perpendicular to the axial direction (X-X) of the gas injector, said second gas injector being smaller than said first through cross-section (a1) of said at least one blowing opening (11).

Description

Gas injector with improved blow-in characteristics

Technical Field

The invention relates to a gas injector for injecting a gaseous medium, in particular a gaseous fuel, having improved injection properties.

Background

Gas injectors are known from the prior art in various embodiments. Gas injectors are used, for example, in gas internal combustion engines, wherein gas injectors have hitherto usually been arranged in the intake tract of the internal combustion engine in order to inject gaseous media, in particular natural gas, into the intake tract. The amount of gas to be blown in is usually set to a certain gas throughput by a stroke adaptation of the opening stroke of the gas injector. However, the problem arises that the amount to be blown in is often not uniform or deviates from the desired blowing amount, since the adjustment of the stroke is subject to certain tolerances. As a result, excessive gas consumption occurs during operation and the emissions of the gas internal combustion engine are negatively influenced. In order to make the amount of blown gas as precise as possible, the valve components of the gas injector must be manufactured with extremely high precision and extremely low tolerance deviations in addition to very precise stroke control. However, the production of such gas injectors is complicated and costly.

Disclosure of Invention

In contrast, the invention proposes a gas injector for injecting a gaseous medium, in particular a gaseous fuel, comprising: a closing element for releasing and closing at least one blow-in opening, wherein the at least one blow-in opening has a first through cross section in a first plane perpendicular to the axial direction of the gas injector, wherein a sealing seat is arranged on the blow-in opening; an actuator for actuating the closing element, and a valve member having at least one first through opening for conducting gaseous fuel therethrough, wherein the at least one first through opening has a second through cross section in a second plane perpendicular to the axial direction of the gas injector, the second through cross section being smaller than the first through cross section of the at least one blow-in opening. The gas injector has the following advantages: low-cost manufacturing can be achieved. In this case, according to the invention, a stroke release (huntdrossing) is carried out, i.e. the gas injector is operated only between two positions, namely a closed position and a fully open position. This eliminates the need for adjustments to determine the stroke of the gas injector during production. In particular, problems which may occur at the blow-in opening due to the use of elastomers as sealing material can be solved thereby, since elastomers are relatively tolerant and therefore the stroke actuation of each gas injector has to be individually checked up to now. This is solved according to the invention in the following way: the gas injector has a closing element for releasing and closing the at least one blow-in opening. The at least one blow-in opening is arranged in a first plane E1, which is perpendicular to the axial direction of the gas valve. The at least one blow-in opening has a first through-opening cross section. A through-cross-section is understood here to be a cross-section defined by the sole blow-in opening in the plane E1, or, in the case of a plurality of blow-in openings, by the sum of the corresponding through-cross-sections of the individual blow-in openings. Furthermore, a sealing seat is arranged on the at least one blow-in opening. Furthermore, the gas injector comprises an actuator for manipulating the closing element and a valve member having at least one first through opening for guiding the gaseous fuel therethrough. The at least one first through opening of the valve member has a second through cross section in a second plane E2 perpendicular to the axial direction X-X of the gas injector. The second through cross section is smaller than the first through cross section. The first passage cross section at the blow-in opening is therefore selected such that it is not the smallest cross section for the gaseous medium to flow through in the axial direction of the gas injector. It should be noted that the opening travel of the closing element from its closing position to its opening position releases a cross section facing the sealing seat which is greater than the through cross section of the second plane. This enables the gas injector to be operated in only two positions, namely the closed position or the fully open position. This can avoid a change in the flow rate due to a stroke tolerance. As a result, a low-cost production of the gas injector can be achieved and, in particular, the actuation of the gas injector can also be designed very simply and at low cost.

The advantageous embodiments show a preferred embodiment of the invention.

It is particularly preferred that the at least one first through opening of the valve member is arranged upstream of the at least one blow-in opening. In particular, the flow rate can be determined exclusively by the second through-cross-section at the first through-opening in the case of a supercritical pressure ratio between the pressure upstream of the first through-opening and the pressure downstream of the first through-opening. Alternatively, the at least one first through opening can also be arranged downstream of the blow-in opening.

The valve member in which the first through opening is arranged is particularly preferably a closing element of a gas injector.

It is further preferred that the closing element has an elastomer for sealing at the sealing seat. In particular, a flat sealing seat can thereby be realized in a simple manner at low cost.

Further preferably, the actuator is an electromagnetic actuator having an armature, which is connected to the closing element. At least one second through-opening is formed in the magnet armature, which is arranged in a third plane E3, which is perpendicular to the axial direction X-X of the gas injector. The at least one second through opening has a third through cross section and is preferably arranged upstream of the first through opening. Particularly preferably, the third through-opening cross section is larger than the second through-opening cross section.

According to a further preferred embodiment of the invention, the gas injector further has an inflow opening with a fourth through-opening cross section. The gaseous medium flows through the inflow opening into the interior of the gas injector. The fourth through cross section is here larger than the second through cross section of the first through opening.

According to a further preferred embodiment of the invention, the gas injector further comprises a control unit which is designed to actuate the actuator of the gas injector in such a way that the closing element is fully opened during each opening operation. In this way, a particularly simple actuation of the gas injector can be achieved.

In order to have as little leakage as possible, the wall gap between the closing element and the other valve component, in particular a valve sleeve, at the radially outer periphery of the closing element is as small as possible, in particular ≦ 1 mm.

A particularly good function of the gas injector is achieved when the first through-cross section of the blow-in opening is at least twice as large as the second through-cross section of the first through-opening. Preferably, the second through cross section is also at least twice as large as the first through cross section.

A particularly good function of the gas injector is achieved when the smallest through-going cross section in the throughflow direction of the gas injector is arranged as far away as possible from the blow-in opening. This advantage is obtained by: the less cross-sections there are in front of the narrowest cross-section, the less pressure losses occur, which are related to the tolerances of these cross-sections. Since in the supercritical case the flow rate is only dependent on the pre-pressure acting at the narrowest cross section, the deviation of the flow rate is also particularly low. This advantage is present in particular always when a supercritical pressure drop is present at the narrowest cross section. In other words, it should preferably be ensured that the pressure loss behind the narrowest cross section is not so great that the subsequent pressure in the flow direction rises to such an extent that there is no longer a critical pressure drop.

The invention further relates to a gas internal combustion engine having the inventive gas injector.

Drawings

Next, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings:

FIG. 1 is a schematic cross-sectional view of a gas injector according to a first preferred embodiment of the invention, an

Fig. 2a schematic enlarged partial cross-sectional view of the gas injector of fig. 1.

Detailed Description

Next, the gas injector 1 according to the first preferred embodiment of the present invention will be described in detail with reference to fig. 1 and 2.

As can be seen from fig. 1, the gas injector 1 comprises a closing element 2 and an actuator 3. In this embodiment, the actuator 3 is an electromagnetic actuator and includes an armature 4, an inner pole 5, and a coil 6.

The electrical terminal 30 is connected to the actuator 3. Furthermore, a control unit 31 for actuating the actuator 3 is also connected to the actuator 3 via this connection.

As can be seen from fig. 2, an elastic body 20 is arranged on the closing element 2. The elastomer 20 seals at the sealing seat 15. In this embodiment, the sealing seat 15 is arranged on the blow hole plate 16.

The blow-in openings 11 are formed in the blow-in perforated plate 16, through which the gaseous medium can be blown into the combustion chamber 10 as in the open state of the gas injector shown in fig. 2. It should be noted that, instead of the injection into the combustion chamber, injection into the intake pipe or the like may be performed.

In fig. 2, the arrows B here show the flow path of the gaseous fuel through the open gas injector 1.

First through

openings

12a,12b are also provided in the closing element 2. Furthermore, a second through-opening 13 is formed in the armature 4. As also shown in fig. 1, a third through-opening 14 in the form of an inflow opening is provided in the gas injector in order to convey the gaseous fuel into the interior of the gas injector. The inflow opening is connected, for example, to a rail or a gas tank.

Furthermore, the gas injector 1 comprises a return element 7, which in this embodiment is a spring element. The reset element 7 resets the closing element into the closed position shown in fig. 1 after the injector has opened.

Furthermore, a wall gap 9 is formed on the outer circumference of the closing element 2 relative to the valve sleeve 8 in order to ensure the mobility of the closing element 2. The wall gap is selected to be as small as possible in order to keep leakage through the wall gap as small as possible in the open state of the injector.

In the closed state, the closing element 2 is sealed at the sealing seat 15 by means of the elastomer 20. In this case, a flat sealing seat can be provided, which can be produced particularly inexpensively and simply. The insufflation opening 11 is kidney-shaped or arcuate in configuration and is completely surrounded by a sealing seat 15, on which the elastomer body 20 seals.

It should be noted here that a plurality of individual blow-in openings 11 are usually provided in the closing element 2. The plurality of blow-in openings are preferably on a common diameter around the central axis of the injector and are closed by an annular elastic body 20.

For reasons of clarity, only one blow-in opening 11 is shown in fig. 2. As can be seen from fig. 2, a first through-cross-section a1 of the blow-in opening 11 is drawn in a first plane E1 perpendicular to the axial direction X-X of the injector. The first through-going cross-section a1 of the blow-in opening is understood here to be the cross-section which is released by the one or more blow-in openings 11 in the open condition of the injector. Here, the first through cross-section is the smallest cross-section at the one or more insufflation openings.

In this embodiment, two closing

element openings

12a and 12b are shown at the closing element 2. The second through-cross-section a2 is formed by the sum of the through-cross-sections of the first and second

closing element openings

12a,12 b. It should be noted here that a plurality of further

closing element openings

12a,12b can also be provided here along the periphery of the closing element. The second through-cross-section a2 is therefore defined by the sum of the through-cross-sections a2' and a2 ″ of the two

closing element openings

12a and 12 b. The sum of all second through-cross-sections a2 of the

closure element openings

12a,12b is here smaller than the sum of the first through-cross-sections a1 of the blow-in openings 11. The second plane E2 is also perpendicular to the axial direction X-X, such that the first plane E1 is parallel to the second plane E2.

By thus determining the first and second through-going cross-sections a1, a2 enables a stroke-relaxed gas injector. The control unit 31 is only further designed such that it is necessary to actuate the actuator 3 between the closed first position and the fully open second position of the closing element 2. In this case, in the fully open position, the armature 4 is in contact with the inner pole 5, the path of the armature 4 being indicated by the arrow a in fig. 2.

Furthermore, a third plane E3 is drawn in fig. 2, which is likewise perpendicular to the axial direction X-X of the gas injector. Here, a minimum third through-cross-section a3 at the second through-opening 13 in the armature 4 is shown. The third through cross section A3 is larger than the second through cross section a2 at the closing element 2.

In fig. 1, a fourth through cross section a4 at the inflow opening 14 is shown in a fourth plane E4 perpendicular to the axial direction X-X. The fourth through-going cross-section a4 is also larger than the second through-going cross-section a 2.

Thus, in the entire injector 1, the second through cross section a2 is the smallest through cross section through all the components of the gas injector through which the gaseous fuel flows.

With regard to the respective through-cross-sections a1, a2, A3, a4 at the blow-in opening 11 and at the first, second and third through-

openings

12a,12b, 13 and 14, it should be noted that in this case an effective through-cross-section must be considered, that is to say a cross-section for which it is also noted that the alternating through-openings are formed in that

But a reduced through cross-section. Preferably, all other through-going cross-sections at the gas injector 1 are at least twice as large as the second through-going cross-section a2 at the closing element 2. In particular, pressure losses which are still effective when flowing through the gas injector can be ignored.

Thus, a gas injector 1 with a flat sealing seat can be provided, wherein the blow-in opening 11 can be produced in particular in a metal component, i.e. in this embodiment in the blow-in orifice plate 16. Since the cross section determining the flow rate is not determined by the elastomer component, a constant and precise blow-in quantity can also be ensured over the service life of the gas valve.

Thus, according to the invention, a gas injector 1 can be provided which does not require a stroke adaptation for influencing the flow rate, but can be operated only in two extreme positions, namely a closed state and a fully open state. In this case, the nominal stroke or the full stroke of the gas injector does not have to be adapted to the injector, in particular by the depth of penetration of the inner pole, which serves as an armature stop surface, to achieve the desired flow rate, since the nominal stroke likewise no longer has an effect on the flow rate. Since the closing element 2 does not need to be finely actuated to determine the predetermined stroke, a very robust, very easily handled gas injector can be realized. Here, a rapid opening and closing of the gas injector can also be achieved.

Claims

1. A gas injector for blowing in a gaseous medium, comprising:

a closing element (2) for releasing and closing the at least one insufflation opening (11),

-wherein the at least one blow-in opening (11) has a first through cross-section (A1) in a first plane (E1) perpendicular to the axial direction (X-X) of the gas injector,

-wherein a sealing seat (15) is arranged on the blow-in opening (11),

-an actuator (3) for actuating the closing element (2), and

-a valve member having at least one first through opening (12a,12b) for guiding gaseous fuel therethrough,

-wherein said at least one first through opening (12a,12b) has, in a second plane (E2) perpendicular to the axial direction (X-X) of the gas injector, a second through cross section (a2) smaller than said first through cross section (a1) of said at least one blow-in opening (11).

2. A gas injector according to claim 1, wherein the first through opening (12a,12b) is arranged upstream of the blow-in opening (11).

3. A gas injector according to claim 1 or 2, wherein the valve member is the closing element (2) and the at least one first through opening (12a,12b) is configured in the closing element (2).

4. Gas injector according to claim 1 or 2, wherein the closing element (2) has an elastomer body (20) for sealing at the sealing seat (15).

5. Gas injector according to claim 1 or 2, wherein the actuator (3) is an electromagnetic actuator having an armature (4), wherein the armature (4) is connected with the closing element (2), wherein at least one second through opening (13) is configured in the armature (4), which through opening has a third through cross section (A3) in a third plane (E3) perpendicular to the axial direction (X-X) of the gas injector.

6. The gas injector of claim 5, wherein the third through cross-section (A3) is larger than the second through cross-section (A2).

7. The gas injector according to claim 1 or 2, further comprising a third through opening (14) having a fourth through cross section (a4), wherein gaseous medium flows into the gas injector through the third through opening (14), wherein the fourth through cross section (a4) is larger than the second through cross section (a 2).

8. Gas injector according to claim 1 or 2, further comprising a control unit (31) which is set up for actuating the actuator (3) in such a way that the closing element (2) is fully opened during each opening.

9. A gas injector according to claim 1 or 2, wherein a wall gap (9) is present between the closing element (2) and a valve sleeve (8) at the outer periphery of the closing element (2).

10. Gas injector according to claim 5, wherein the first through cross section (A1) at the blow-in opening (11) is at least twice the second through cross section (A2) at the closing element opening (12a,12b) and/or the third through cross section (A3) in the armature (4) is at least twice the second through cross section (A2) of the first through opening (12a,12 b).

11. A gas injector as claimed in claim 1 or 2, wherein the gaseous medium is a gaseous fuel.