WO2014202473A1

WO2014202473A1 - Pressure regulating valve

Info

Publication number: WO2014202473A1
Application number: PCT/EP2014/062328
Authority: WO
Inventors: Bernd Stuke; Alexander Wernau; Martin Katz
Original assignee: Robert Bosch Gmbh
Priority date: 2013-06-21
Filing date: 2014-06-13
Publication date: 2014-12-24
Also published as: DE102013219418A1

Abstract

Pressure regulating valve (2), having at least one medium inlet opening (4a), at least one medium outlet opening (4b), a valve element (6), arranged between the medium inlet opening (4a) and the medium outlet opening (4b) and set up to assume an open state and a closed state, wherein, in the open state, a medium connection is produced between the medium inlet opening and the medium outlet opening, and wherein, in the closed state, a medium connection is suppressed between the medium inlet opening and the medium outlet opening, and a drive unit (8), set up to set the valve element (6) in an open state, closed state and/or between said states; characterized by a medium-proof sealing element (12), arranged between the valve element (6) and the drive unit (8), with the result that the pressure regulating valve (2) has a medium-loaded, first region (18a) with medium inlet opening, valve element and medium outlet opening, and a second region (18b) with drive unit, wherein the medium of the first region cannot pass over into the second region.

Description

description

title

Pressure control valve

The present invention relates to a pressure regulating valve having the features of

The preamble of claim 1. State of the art

Pressure control valves are used for example in fuel injection systems

Injection of fuel used in a combustion chamber of an internal combustion engine. In particular, pressure control valves are used in common rail injection systems for diesel engines. In these systems, a high-pressure pump delivers the fuel to be injected to high pressure and feeds it to a high-pressure accumulator, the so-called common rail. In the high pressure accumulator, a pressure control valve may be provided to adjust and maintain the pressure in the rail depending on a predetermined target pressure. Pressure control valves are often designed as solenoid valves.

Fig. 1 shows a conventional pressure control valve.

The pressure regulating valve 2 of FIG. 1 has a medium inlet opening 4a and a medium outlet opening 4b. The medium outlet opening 4b is schematically divided in FIG. 1 into a total of four indicated medium outlet openings 4b. One

Valve element 6, formed from a valve ball 6a, which is pressed by a rod member 6c in the valve seat 6b, is further provided. Using the drive unit 8, which acts on rod element 6 c, opening and closing of the valve element 6 can be achieved by releasing or pressing the valve ball 6 a from / to the valve seat 6 b.

The pressure control valve 2 is characterized in that the valve ball 6a is held in the control position by means of the rod element 6c, the stroke of the ball valve or valve element 6 is thus adjusted in such a way that via the valve seat

desired pressure difference is adjustable. The counterforce to the hydraulic load through the pressure control valve to be transported medium is provided via the drive unit 8, exemplified by a magnetic actuator provided. To achieve a high control quality, the hydraulic forces near the operating point must not vary significantly.

A flow of the medium from the medium inlet opening 4a via the valve element 6 to the medium outlet openings 4b, however, in a conventional

Pressure control valve, after the medium has passed the narrowest cross section in the valve seat, axially guided along the rod member radially outward. Here are two flow paths possible. A flow path runs along the spherical surface, following the rod element up to the medium outlet openings 4b, another along the conical valve seat up to the medium outlet openings 4b.

Both medium paths are almost equal and can change continuously during operation. As a result, the force on the rod element and thus also the force balance changes. This may lead to instabilities, in particular noise generation or formation of pressure waves in the pressure control valve, which couple into the connected low-pressure circuit and thereby trigger or amplify interference.

The conventional pressure control valve has a long guide for the

Bar element between the actual valve element 6 and the drive unit 8. As a result, further disturbing forces, for example due to formation of deposits in the guide, lack of ventilation or pumping losses from armature upper side to underside, in particular due to the fact that all components in the pressure control valve

medium-loaded, thus are in contact with the medium to be transported.

Disclosure of the invention

The object of the present invention is to provide an improved

Provide pressure control valve with a modified structure, in which on the one hand the drive unit is not medium-loaded and on the other hand has a changed flow behavior of the medium. To achieve the object, a pressure regulating valve with the features of claim 1 is given. Preferred embodiments will be apparent from the dependent

Claims. Furthermore, a high pressure accumulator is proposed with such a pressure control valve.

According to the invention, the pressure regulating valve is constructed in such a way that, on the one hand, a medium-loaded first region and a second region which is not medium-stressed are formed. This is achieved in that the pressure regulating valve has a medium-tight sealing element, which is the range of

Medium inlet, medium outlet and valve element from the remaining pressure control valve, in particular from the drive unit, separates. The medium through the pressure regulating valve is thus substantially exclusively in the range of

Inlet opening arranged over the valve element to the outlet opening.

In the open state of the valve element, a medium connection between the inlet opening and the outlet opening is realized. Medium connection in this context means that a medium entering through the inlet opening in the

Pressure control valve flow and exit via the outlet may like.

According to the invention, the medium-tight sealing element is realized, for example, by providing the sealing element directly above the valve ball, for example in the form of an elastic membrane. This is the actuator part of the

Valve part separated, no medium can reach the actuator. Due to the flexibility of the membrane, the drive unit, which may be of conventional construction, acts on one side of the sealing element, while the valve element, in particular with its constituent valve ball and valve seat, is arranged on the other, opposite side of the membrane.

A holder of the valve ball, for example, by a suitable

Receiving element, for example, a dome element, be realized, which on the one hand provides a certain guidance of the valve ball, on the other hand can also be designed such that the valve ball mounted in the holding element or

is held positively or non-positively. The holding element itself in turn can be positively mounted on the sealing element. By a suitably ausgestaltetes sealing element with, for example, a bias voltage, the valve element in a rest state without external power supply, in particular without power supply by the drive unit, be designed such that it remains in an open state. The application of force by the drive unit can thus be used essentially exclusively for closing the valve element.

The drive unit itself need not be frictionally connected to the sealing element, but can only apply a force on the sealing element, which deforms this due to its flexibility and thereby the

Valve element and in particular the valve ball moves, for example, presses on the valve seat, thereby closing the valve element and thus the pressure control valve. Due to the medium separation and in particular the non-admission of the

Drive side with medium can thus no medium to drive, for example, trained as a magnetic drive, even reach, it can thus include no air or other gases, and also the formation or deposition of viscous medium at low temperatures to the drive unit and

In particular, the rod element of the drive unit is thus avoided.

Decomposition products can not settle in the guide of the rod and there is no temperature input from the medium to the drive unit. This results in that cheaper materials can be used on the drive side, which in particular need not be media-resistant.

On the drive side, the surrounding medium may be air, alternatively, due to the encapsulation of the pressure control valve, a (different) suitable medium, such as a suitable silicone oil, are filled. The sealing effect of the membrane can be supplemented by further sealing elements, such as an O-ring.

Demands on the medium-tight sealing element can be assumed to be comparatively low. A diaphragm must not be made too thick in order to be able to transmit elastically the power of the drive unit. The membrane requires a sufficiently high compressive strength against occurring pressure surges and can additionally take over the function of a spring to open the valve in a defined manner or to keep it open without power. The holding element or dome element can be suitably connected to the membrane, in particular by a magnetic

Bracket.

Due to the separation of the medium-loaded region of the pressure regulating valve from the non-medium-loaded drive region of the pressure regulating valve, different drive technologies can be used. Thus are

Drive units, designed as a plunger armature or flat armature, feasible, with a particular design is particularly dependent on an operating characteristic of the drive unit, which should be designed such that, together with the

hydraulic valve characteristic results in the greatest possible stability of the drive.

Due to the non-mediumbeaufschlagten drive side of the pressure control valve, a conventionally provided rod element may be much shorter or in the

Essentially completely eliminated. May completely be omitted in particular be understood that a rod member only has such a length, which no longer needed or no longer has the conventionally required function of the stabilization in a guide, especially due to the lack of

Mediumbeaufschlagung. At the same time due to the mounting of the valve ball through the medium-tight sealing element together with the holding element a

Centering function by the rod no longer be required.

By a suitably formed surface of the holding element, in particular in conjunction with the surface of the valve ball and the valve seat, thus, a stable medium flow may be realized. By providing a substantially unique flow path, the flow around the valve ball can be stabilized. This may be achieved particularly preferably by the

Medium flow guided along the valve seat and is prevented by the holding element from flowing around the valve ball over a large area. Furthermore, the medium outlet in

Are area of the valve seat or even below the valve seat, whereby a discharge is provided radially outward substantially.

A further advantageous development is that the sealing element, in particular a membrane, has means for pressure measurement, with which a Deformation of the sealing element can be detected and wherein on the deformation of the sealing element, a pressure can be determined. Such a pressure measurement provides information about the pressure in the rail, wherein the pressure measurement on the

Sealing element is more accurate than a model-based pressure determination via the actuator flow of the pressure control valve. It is particularly advantageous if the means for

Pressure measurement include strain gauges. About strain gauges can be easily, inexpensively and with high accuracy detect a deformation of the sealing element, in particular a sealing membrane, whereby a relatively accurate

Pressure measurement on the pressure control valve is possible. It is particularly advantageous if the strain gauges on the magnetic actuator side facing the

Membrane are arranged. By arranging on the "dry" side, i.e. not in contact with the medium, a simple contacting of the

Strain gauges possible, there is also no risk of damage due to deposits of the medium.

Since the advantages of the present invention, in particular when using the

Pressure control valve in a high-pressure accumulator for a fuel injection system come to fruition, a high pressure accumulator is further indicated with a pressure control valve according to the invention.

Embodiments of the invention are illustrated in the figures and explained in more detail in the following description.

Show it:

1 shows an exemplary embodiment of a pressure regulating valve;

Fig. 2a, b show exemplary embodiments of pressure control valves according to the present invention; and

3 is a detailed representation of an exemplary embodiment of the

Mediumbeaufschlagten area of the pressure control valve according to the present invention in juxtaposition with known pressure control valves. Fig. 4 is a sealing element of a pressure control valve according to the invention

Still referring to FIGS. 2a, b, exemplary embodiments of pressure control valves according to the present invention are illustrated.

2 a, b are schematic representations of different embodiments of the pressure control valve 2. Essentially, the pressure control valves according to FIGS. 2 a and 2 b differ by their drive unit 8, which in FIG. 2 a functions as a magnetic drive unit with plunger armature and in FIG magnetic drive unit is formed with flat armature. Other types of drives or

Drive units are conceivable, for example a piezoactuator. all

Drive units in common is ultimately that they have to exert a comparatively small stroke on the medium-tight sealing element 12, so that via the holding element 14 valve ball 6a is pressed onto the valve seat 6b, whereby the pressure control valve 2 closes, thereby the medium connection between

Medium inlet opening 4a and medium outlet 4b prevents.

By way of example, the pressure regulating valve 2 will now be described with reference to FIG. 2a. A medium, for example diesel fuel, enters the pressure regulating valve 2 via the medium inlet opening 4a. In Fig. 2a, the pressure control valve 2 is shown in the closed state, thus the valve element 6 is closed by the valve ball 6a rests on the valve seat 6b. Valve ball 6a is suitably formed

Received holding device or holding element 14 and held in this, for example, a dome element, positive or non-positive. The holding element 14 is attached to the medium-tight sealing element 12, which has a certain flexibility on the one hand and a certain bias on the other hand, so that in

Idle state, thus without force applied by the drive unit 8, the valve element 6 would be in the open state. The rod member 10 of the drive unit 8 engages the valve element 6 opposite side of the medium-tight sealing element and this by suitable force, in Fig. 2a directed downwards, also to move down and so put valve ball 6a towards the valve seat 6b or on press this. The pressure control valve 2 forms due to the medium-tight

Sealing element 12 a first region 18 a, which is mediumbeaufschlagt, as well as a second region 18b which is substantially non-medium-pressurized.

In the open state of the pressure regulating valve 2, the medium flows over

Medium inlet opening 4a past the valve seat 6b and valve ball 6a and flows in

Direction of the Mediumauslassöffnung 4 b, which in Fig. 2a schematically to one side, the right side goes out, then out, then down and then exits in the circumferential direction of the pressure control valve, wherein in Fig. 2a, b only a single exit to the left Page is shown. The exact arrangement and

Distribution of Mediumauslassöffnungen 4b is regularly a concrete

Implementation and a specific purpose of a pressure control valve 2 according to the invention owed.

Due to the medium-tight sealing element 12, the drive unit 8 is medium-freed. This may be e.g. not necessarily be a suitably trained

Guide, at least not as long guide, as this is necessary, for example, in conventional pressure control valves without medium-free second area 18b provide. Rather, rod element 10 can be made comparatively short and essentially immediately following the drive unit 8 on the

medium-density sealing element 12 act. Due to the design, at least a slight guidance of the rod element 10 of the drive unit 8 may or may not be necessary.

be provided, as shown for example in Fig. 2b. It is noticeable here, however, that the guide is considerably shortened in comparison with the prior art, in particular in that rod element 10 does not have to take over a centering function, as is necessary in the state of the art.

Still referring to FIG. 3, a detail of one exemplary embodiment of the medium-pressurized portion of the pressure control valve of the present invention is shown in juxtaposition with prior-art pressure control valves.

FIG. 3 shows a detailed illustration of the valve element 6 or of the first area 8a of the pressure regulating valve 2. The left side of Fig. 3 illustrates the arrangement in a known pressure control valve, while the right side, to the right of the dashed center axis, represents a structure according to the present invention. In known pressure control valves it is shown that the medium has two possible flow paths 1 and 2 and in particular can switch between them. Flow course 1 takes place essentially along the surface of the

Valve seat, while flow path 2 is formed substantially following the surface of the ball. Due to these two possible flow patterns, the exact course is unpredictable, thus difficult to control and unstable.

In comparison, the flow of the flow in the pressure control valve 2 according to the invention is shown on the right side. In particular, characterized in that the ball valve 6a is enclosed over a large area by the holding element 14 or the Kalottenelement 14, the second flow path of the medium is prevented, since this can no longer flow over the spherical surface, but after a short distance already on

Retaining element 14 arrives and is diverted from this or.

As a result, and in particular through a medium outlet opening 4b in the region of the valve seat, a, in Fig. 3, right side, downwardly directed stable

Medium flow formed. Depending on the configuration of the pressure control valve 2 according to the invention, the space next to the holding element 14 may be designed to be favorable in terms of flow, in particular cavities may be cut off, as indicated in FIG. 3 by the reference numeral 20. This makes it possible to provide a particularly stable medium flow.

4, a sealing element 12 of a pressure control valve 2 according to the invention is shown. The sealing element 12 is designed as a sealing membrane and contributes to his

Surface means for pressure measurement 30, in this embodiment, three evenly distributed over the circumference of the sealing membrane strain gauges 32nd Die

Sealing membrane is designed so that on one side the dome element 14 is attached together with valve ball 6a, on the other side a rod member 10 presses by means of a controllable magnetic force on the sealing membrane. If the magnetic force is reduced, the valve ball 6a rises from the valve seat 6b and the diaphragm deforms due to this load. The load is directly dependent on the pressure in the high-pressure accumulator. Thus, it is possible, the pressure in the high pressure accumulator in addition to a rail pressure sensor with high accuracy and independent of this rail pressure sensor to monitor. As actuators both plunger armature and flat armature according to the embodiments in Fig. 2a and Fig. 2b are conceivable.

Claims

Pressure control valve (2), comprising

at least one medium inlet opening (4a) and at least one medium outlet opening (4b);

a valve element (6) disposed between the medium inlet port (4a) and the medium outlet port (4b) and configured to assume an open state and a closed state,

wherein in the opened state a medium connection between the medium inlet opening (4a) and the medium outlet opening (4b) is provided, and wherein in the closed state, a medium connection between the medium inlet opening (4a) and the medium outlet opening (4b) is prevented; and a drive unit (8) arranged to move the valve element (6) from an open state to a closed state, or a state between these states;

marked by

a medium-tight sealing element (12) arranged between the valve element (6) and the drive unit (8), so that the pressure regulating valve (2) has a

having medium-loaded, first region (18a) with medium inlet opening (4a), valve element (6) and medium outlet opening (4b) and a second region (18b) with drive unit (8), wherein the medium of the first region is not in the second Area can cross.

Pressure control valve according to claim 1,

characterized in that the valve element (6) as a ball element (6a) is formed and on the sealing element (12) has a holding element (14), in particular a dome element with an at least partially circular opening for receiving or for abutment of the valve element (6). is attached, in particular mounted in a form-fitting manner. Pressure control valve according to claim 2,

characterized in that the holding element (14) is designed such that the ball element (6a) is held in the at least partially circular opening, in particular is held in a form-fitting manner.

Pressure control valve according to claim 2,

characterized in that the valve element (6) and the holding element (14) are integrally formed, so that an element with at least one

part-circular surface on the sealing element (12) is mounted, in particular is mounted in a form-fitting manner.

Pressure control valve according to one of claims 1 to 4,

characterized in that the drive unit (8) is formed as a unit from the group consisting of magnetic actuator with flat armature,

Magnetic actuator with solenoid and piezoelectric actuator.

Pressure control valve according to one of claims 1 to 5,

characterized in that the drive unit (8) without external

Power supply assumes a state in which the valve element (6) is in the open state.

Pressure control valve according to one of claims 1 to 6,

characterized in that the valve element (6) and the at least one medium inlet opening (4a) are formed such upon contact of valve element (6) and medium inlet port (4a) form the closed state, so that the medium connection between the medium inlet port (4a) and medium outlet opening (4b) is prevented.

Pressure control valve according to one of claims 1 to 7,

characterized in that the surfaces of medium inlet opening (4a), valve element (6) and retaining element (14) in the transition region or sealing region of sealing element (12) and medium inlet opening (4a) are formed such a substantially defined or stable Provide medium flow.

9. Pressure control valve according to one of claims 1 to 8,

characterized in that the sealing element (12) is formed as a, elastic membrane element consisting of a metallic material, designed as a spring element.

10. Pressure control valve according to one of claims 1 to 9, characterized in that on the sealing element (12) means for pressure measurement (30) are arranged, which detect a deformation of the sealing element (12).

11. Pressure control valve according to claim 10, characterized in that the means for pressure measurement (30) comprise strain gauges (32).

12. Pressure control valve according to claim 9 and claim 11, characterized in that the strain gauges (32) are arranged on the magnetic actuator side facing the membrane, in particular at regular intervals.

13. High-pressure accumulator for a fuel injection system, in particular common rail injection system, with a pressure control valve (2) according to at least one of the preceding claims.