WO2003038266A1

WO2003038266A1 - Liquid flow rate control valve

Info

Publication number: WO2003038266A1
Application number: PCT/DE2002/003701
Authority: WO
Inventors: Werner Hassel; Christian Postler
Original assignee: Robert Bosch Gmbh
Priority date: 2001-10-20
Filing date: 2002-09-30
Publication date: 2003-05-08
Also published as: DE10152253A1; DE10152253B4

Abstract

The invention concerns a liquid flow rate control valve, comprising a piezoelectric actuator (2), a transmission device (3), a control valve (13), an intermediate disc (12) and an injector needle (14) arranged in an injector body (13). The intermediate disc (12) comprises a first inlet (22) for communication between a high pressure duct (19) and a control chamber (25). The intermediate disc (12) also comprises an outlet (23) for communication between the control chamber (25) and the control valve (8) and a second inlet (24) for communication between the high pressure zone and the control valve (8), as well as a high pressure bore (21). The invention provides an inexpensive leak-proof valve.

Description

Valve for controlling liquids

State of the art

The present invention relates to a valve for controlling liquids, in particular for a fuel storage injection system of an internal combustion engine according to the preamble of claim 1.

Valves for controlling liquids are known, for example, as fuel injection valves in different configurations. The known valves have a nozzle needle which is arranged in a nozzle body. The nozzle needle is controlled via a control valve which is connected to an actuator, for example a piezo actuator. For this purpose, the nozzle needle is arranged in a control chamber, which is formed by a control chamber sleeve arranged at the end of the nozzle needle and an intermediate disk. A flow restrictor goes from the control room to the control valve. Furthermore, an inlet throttle is provided in the control chamber sleeve in order to provide a connection between the control chamber and the high-pressure region of the valve. A nozzle closing spring, which is connected to the nozzle needle, acts on the control chamber sleeve by a closing force for the nozzle needle provide. If fuel is to be injected, the control valve is opened so that the control chamber is connected to a low-pressure region of the valve via the outlet throttle, so that the nozzle needle lifts off its seat. The nozzle needle moves against the force of the nozzle closing spring. When the injection is to be ended, the control valve is closed again, so that the original pressure can build up again in the control chamber, so that the nozzle needle closes the injection nozzles of the valve again.

With such fuel injection valves, however, it is disadvantageous that problems arise in particular with regard to the sealing in the area of the control chamber sleeve. Furthermore, there is disadvantageous wear on the control chamber sleeve, which can lead to inaccuracies in the dimensioning of the injection quantity. In addition, the known injection valve has a large number of individual parts, the production of which is very cost-intensive and which necessitate increased assembly effort. In particular, the nozzle needle and the control chamber sleeve together with the associated additional components are very expensive to manufacture. Furthermore, the known fuel injection valves have a relatively long closing time, so that deviations in the predetermined fuel injection quantity can result.

Advantages of the invention

The valve according to the invention with the features of claim 1 has the advantage that it has a simple and compact structure and is particularly inexpensive to manufacture. ^' The valve closing time can be reduced further. There According to the invention, a smaller number of sealing points are present, a safe and reliable sealing between the high-pressure and low-pressure areas of the valve can also be ensured. This is achieved according to the invention in that the valve comprises a piezo actuator, a translator, a control valve, an intermediate disk and a nozzle needle arranged in a nozzle body. One end of the nozzle needle closes an injection opening and the other end of the nozzle needle is arranged in a control room. A first inlet, an outlet, a second inlet and a high-pressure bore are arranged in the intermediate disk. The first inlet connects a high pressure area with the control room. The drain connects the control room with the control valve. The second inlet connects the high pressure area with the control valve. This inventive design of the intermediate disk makes it possible for the number of components of a valve to be reduced, since the control chamber sleeve on the nozzle needle, which is necessary in the prior art, can be dispensed with. Thus, according to the invention, the manufacturing costs and the assembly costs can be significantly reduced. Furthermore, the valve according to the invention is constructed with very little wear and allows the use of simply constructed nozzle bodies and nozzle needles. Furthermore, according to the invention, a very good separation between the high pressure area and the low pressure area of the valve is possible. The nozzle is particularly pressure-resistant up to approx. 2050 bar.

A faster closing of the nozzle needle is achieved in particular via the second inlet of the intermediate disk, since during the closing process, fluid can flow into the control chamber via the first inlet on the one hand, and via the second inlet and outlet to the other Control room flows. The flow direction in the drain is reversed compared to an open valve.

The control chamber is particularly preferably formed by a recess in the nozzle body. This makes it possible to provide a particularly compact valve with small axial dimensions.

According to another preferred embodiment of the present invention, the control space is formed by a cutout in the intermediate disk. This allows even smaller axial dimensions of the valve to be achieved. It should be noted that the control chamber can also be formed in such a way that it is partially formed both in the nozzle body and in the intermediate disk and thus arises when the valve is mounted on the transition region between the intermediate disk and the nozzle body.

More preferably, a spring seat is formed in the washer to receive a nozzle closing spring. The nozzle closing spring is used to close the nozzle spring, the spring force having to be overcome when the nozzle needle is opened.

According to another preferred embodiment of the present invention, the nozzle closing spring is supported on the end face of the intermediate piece directed towards the nozzle needle.

In order to enable the nozzle closing spring to be securely attached to the nozzle needle, a spring seat is preferably formed at the end of the nozzle needle facing the control chamber. According to a particularly preferred embodiment of the present invention, the second inlet is connected to the high-pressure region of the valve via a separate bore in the nozzle body. On the one hand, this enables an asymmetrical deformation of the nozzle body to be compensated for, and on the other hand, seat relaxation is largely avoided.

According to another preferred embodiment of the present invention, the second inlet is arranged in the washer in such a way that it branches off directly from the high-pressure bore of the washer. This eliminates the need for a second separate hole in the nozzle body.

According to a further preferred embodiment of the present invention, the nozzle needle is closed exclusively by the fluid pressure from the high-pressure region of the valve, which is fed into the control chamber via the first and the second inlet. This makes it possible according to the invention to dispense with the closing springs for the nozzle needle, so that further savings potential can be realized on the valve according to the invention.

In order to enable a safe movement of the nozzle needle in the nozzle body, a chamfer is preferably provided on the end of the nozzle needle facing the control chamber.

The valve according to the invention for controlling liquids is used in particular as a fuel injection valve in storage injection systems. Both a mechanical and a hydraulic translator can be used as the translator for the stroke of the piezo actuator. drawing

Several embodiments of the invention are shown in the drawing and are explained in more detail in the following description.

FIG. 1 shows a schematic sectional view of a fuel injection valve according to a first exemplary embodiment of the present invention,

FIG. 2 shows an enlarged detailed view of the valve shown in FIG. 1,

FIG. 3 shows a schematic partial cross-sectional view of a fuel injection valve according to a second exemplary embodiment of the present invention,

FIG. 4 shows a schematic partial cross-sectional view of a fuel injection valve according to a third exemplary embodiment of the present invention, and

FIG. 5 shows a schematic partial cross-sectional view of a fuel injection valve according to a fourth exemplary embodiment of the present invention.

Description of the embodiments

A fuel injection valve 1 according to a first exemplary embodiment of the present invention is described below with reference to FIGS. 1 and 2. As shown in Figure 1, this includes

Fuel injection valve a piezo actuator 2, which is connected to a hydraulic booster 4 via an actuating piston 3. The hydraulic intensifier 4 consists of a first piston 5, a second piston 6 and a pressure chamber 7 arranged between the two pistons. The second piston 6 is connected to a control valve 8 via an actuating element. The control valve 8 comprises a valve member 9, which bears against a valve seat 10 when the piezo actuator is not actuated.

Furthermore, the fuel injection valve comprises an intermediate piece 12 and a nozzle body 13, in which a nozzle needle 14 is arranged. The nozzle needle 14 opens or closes a plurality of injection openings 20 through which fuel can be injected into a combustion chamber (not shown) of an engine. The lifting height of the nozzle needle 14 is designated by H in FIGS. 1 and 2.

The intermediate piece 12 according to the invention is shown in detail in FIG. As shown in FIG. 2, a high-pressure bore 21, an inlet throttle 22, an outlet throttle 23 and a second inlet 24 are formed in the intermediate piece 12. The high-pressure bore 21 connects a high-pressure line 19, via which a fuel under high pressure is fed from a high-pressure pump, not shown, to a bore 17 in the nozzle body 13. The bore 17 leads to a high-pressure region 16 of the valve. The inlet throttle 22 connects the high-pressure bore 21 to a control chamber 25. The control chamber 25 is connected to the control valve 8 via the outlet throttle 23. Furthermore, the control valve 8 is connected to the high-pressure region 16 of the valve via the second inlet 24 and a bore 18 (cf. FIG. 2). One end of the nozzle needle 14 is also arranged in the control chamber 25, a wide chamfer 29 being formed on the nozzle needle 14. A nozzle closing spring 26 is arranged in a recess 27, which is also formed in the intermediate piece 12. The nozzle closing spring 26 is thus supported on the one hand on the intermediate piece 12 and on the other hand on the nozzle needle 14.

The individual components of the valve are held together in a known manner via a nozzle clamping nut 15 (cf. FIG. 1). The nozzle needle 14 is further guided into the nozzle body 13 via a needle guide 30. Furthermore, a shoulder 31 is formed on the nozzle needle 14 and is positioned in the high-pressure region 16 of the valve.

- J -_Ξ -.i: - Xc ~ _i --X3S fuel injection valve according to the first embodiment is as follows: When fuel is to be injected, the piezo actuator 2 is activated so that it lengthens. This stroke of the piezo actuator 2 is transmitted via the actuating piston 3 and the hydraulic translator 4 to the valve member 9 of the control valve 8, which stands out from its valve seat 10. This opens a connection to the low-pressure region 11. More precisely, the control chamber 25 is connected to the low-pressure region 11 via the cutout 27 and the outlet throttle 23. As a result, the pressure in the control chamber 25 drops, as a result of which the nozzle needle 14 is moved upward into the control chamber 25 by the pressure on the shoulder 31 in the high-pressure region 16, so that the nozzle needle 14 lifts off its seat. As a result, fuel is injected at the injection openings 20. The nozzle needle 14 is moved against the force of the nozzle closing spring 26. When the injection of fuel is to be stopped, the piezo actuator 2 is activated again, so that it shortens again to its original length. As a result, the valve member 9 moves back onto its valve seat 10, so that the connection to the low-pressure region 11 is interrupted again. As a result, a higher pressure can build up in the control chamber 25, which leads to the closing of the nozzle needle 14. This higher pressure in the control chamber 25 is provided on the one hand via the connection to the high-pressure bore 21 provided by the inlet throttle 22 and also via the connection from the high-pressure region 16 via the bore 18 and the second inlet 24 and the outlet throttle 23. The flow direction reverses in the Flow restrictor 23 um. This makes it possible according to the invention that the nozzle needle 14 closes more quickly. JoexeJtge.ste.- lt ωird_

The formation of the intermediate disks 12 with the high-pressure bore 21, the inlet throttle 22, the outlet throttle 23, the second inlet 24 and the recess 27 for receiving the nozzle closing spring 26 thus enables a particularly compact valve according to the invention. The control chamber 25 is formed in the nozzle body 13. As a result, the control chamber sleeves used in the prior art can be dispensed with according to the invention, which on the one hand significantly increase the manufacturing costs and on the other hand lead to sealing problems in the area of the sleeves. In contrast, in the valve 1 according to the invention, the high pressure area and the low pressure area are safely separated from one another via the control valve 8. Furthermore, the symmetrical arrangement of the two bores 17 and 18 achieves a symmetrical pressure distribution in the nozzle body 13. A fuel injection valve according to a second exemplary embodiment of the present invention is described below with reference to FIG. 3. The same or functionally identical parts are designated with the same reference numerals as in the first embodiment.

As shown in FIG. 3, in contrast to the first exemplary embodiment, the nozzle closing spring 26 is arranged in the second exemplary embodiment in such a way that it is supported on the one hand on an end face of the intermediate piece 12 directed towards the nozzle needle 14 and on the other hand on a spring seat 28 formed on the nozzle needle 14. In this exemplary embodiment, however, it would also be possible for an enlarged cutout to be arranged in the intermediate piece 12. so__da_S3 sich- jder_iteuexraιιιιι s.owohJ JLTL dan

Nozzle body 13 and extends into the intermediate piece 12. Otherwise, the second exemplary embodiment essentially corresponds to the first exemplary embodiment, so that reference can be made to the description given there.

A third exemplary embodiment according to the present invention is described below with reference to FIG. Identical or functionally identical parts are designated with the same reference symbols as in the previous exemplary embodiments.

In contrast to the two previous exemplary embodiments, the valve 1 according to the third exemplary embodiment has no nozzle closing spring. In the third exemplary embodiment, the nozzle needle 14 is closed in such a way that the closing operation is carried out exclusively by the hydraulic pressure. For this purpose, the surfaces on the shoulder 31 of the nozzle needle 14 on the one hand and the surface of the nozzle needle 14 facing the control chamber 25 are different, so that a resultant force is generated in the direction of the closing direction of the nozzle needle 14 when the control valve 8 is closed. Otherwise, the third exemplary embodiment corresponds to the two previous exemplary embodiments, so that reference can be made to the description there.

FIG. 5 shows a fuel valve 1 according to a fourth exemplary embodiment of the present invention. Identical or functionally identical parts are again identified by the same reference numerals as in the previous exemplary embodiments.

Embodiment also no closing spring. Furthermore, the second high-pressure inlet 24 is arranged in the intermediate piece 12 such that the second inlet establishes a direct connection between the high-pressure bore 21 and the control valve 8 (cf. FIG. 5). This makes it possible to dispense with the second bore in the nozzle body 13. As a result, the valve according to the invention can be manufactured even more cost-effectively. The function of the valve again corresponds to the function of the exemplary embodiments described above, the second inlet 24 also being used for faster closing of the nozzle needle 14. It should be noted that the arrangement of the second inlet 24 according to the fourth exemplary embodiment can also be used in the other exemplary embodiments. The present invention thus relates to a valve for controlling liquids with a piezo actuator 2, a translator 3, a control valve 8, an intermediate disk 12 and a nozzle needle 14 arranged in a nozzle body 13. A first inlet 22 is connected to the intermediate disk 12 a high-pressure line 19 with a control chamber 25 is provided. Furthermore, an outlet 23 for connecting the control chamber 25 to the control valve 8, a second inlet 24 for connecting the high pressure region to the control valve 8 and a high pressure bore 21 are arranged in the intermediate disk 12. This provides an inexpensive and leak-proof valve according to the invention.

The preceding description of the exemplary embodiments according to the present invention only serves

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Limitation of the invention. Various changes and modifications are possible within the scope of the invention without leaving the scope of the invention and its equivalents.

Claims

Expectations

1. Valve for controlling liquids comprising a piezo actuator (2), a translator (3), a control valve (8), an intermediate disk (12) and a nozzle needle (14) arranged in a nozzle body (13), one end of the nozzle needle (14) at least one

the nozzle needle (14) is arranged in a control chamber (25), characterized in that in the intermediate disk

(12) a first inlet (22) for connecting a high-pressure area to the control chamber, an outlet (23) for connecting the control chamber (25) to the control valve

(8), a second inlet (24) for connecting the

High pressure area with the control valve (8) and a high pressure bore (21) are arranged.

2. Valve according to claim 1, characterized in that the control chamber (25) through a recess in the nozzle body

(13) is formed.

3. Valve according to claim 1 or 2, characterized in that the control chamber (25) is formed by a recess in the intermediate plate (12).

4. Valve according to one of claims 1 to 3, characterized in that a recess (27) is formed in the intermediate disc (12) to receive a nozzle closing spring (26).

5. Nentil according to one of claims 1 to 3, characterized in that the nozzle closing spring (26) is supported on the end face of the intermediate piece (12) directed towards the nozzle needle (14).

6. Valve according to claim 4 or 5, characterized in that a spring seat (28) is formed at the end of the nozzle needle (14) directed towards the control chamber (25).

7. Valve according to one of claims 1 to 6, characterized in that the second inlet (24) via a separate bore (18) in the nozzle body (13) with the

8. Valve according to one of claims 1 to 6, characterized in that the second inlet (24) is arranged in the intermediate plate (24) such that the second inlet (24) directly from the high pressure bore (21) of the intermediate plate (12) branches to the control valve (8).

9. Valve according to one of claims 1 to 8, characterized in that the closing of the nozzle needle (14) takes place exclusively by fluid pressure from the high pressure region of the valve, which on the one hand via the first inlet (22) and on the other hand via the second inlet (24) and the drain (23) is fed to the control room (25).

10. Valve according to one of claims 1 to 9, characterized in that at the control room (25) directed side of the nozzle needle (14) a chamfer (29) is formed.