DE102021106523A1 - Flow control valve for controlling or regulating a mass flow of a fluid and method for operating such a flow control valve - Google Patents

Abstract

The present invention relates to a flow control valve (10) for controlling or regulating a mass flow of a fluid, comprising a first pressure chamber (34) fluidically connected to an inlet (14), a second pressure chamber (70) fluidically connected to an outlet (16), a Tappet (76), a valve seat (46), and a piston (38), which is mounted in the valve housing (12) so that it can move along the longitudinal axis (L) and can be moved by means of the tappet (76) along the longitudinal axis (L) between a first end position and a second end position, forms a through-channel (50) which fluidically connects the first pressure chamber (34) and the second pressure chamber (70) to one another at least in the second end position, has a sealing section (40) which, in the first end position, is on the valve seat (46) and in the first end position the first pressure chamber (34) fluidly separates from the second pressure chamber (70), and has a control groove (62) which provides a flow cross-sectional area, wel which fluidly connects the through-channel (50) and the first pressure chamber (34) or the through-channel (50) and the second pressure chamber (70), the size of the flow cross-sectional area depending on the position of the piston (38) between the first end position and the second end position is changeable. The invention also relates to a method for operating such a flow control valve (10).

Description

The present invention relates to a flow control valve for controlling or regulating a mass flow of a fluid. In addition, the invention relates to a method for operating such a flow control valve.

Catalytic converters, which are used for the aftertreatment of exhaust gases emitted by internal combustion engines of motor vehicles, require a minimum operating temperature in order to be able to treat the exhaust gases to their full extent. The lower limit of the minimum operating temperature is approximately in the range of 160°C to 180°C. So far, the thermal energy contained in the exhaust gas has been used to heat up the catalytic converter, which, however, leads to the situation that the minimum operating temperatures are only reached on average after a minimum operating time of the internal combustion engine of 10 minutes or longer. The minimum operating time depends on many factors, of which the outside temperature and the type of route driven are two of the most important factors. The lower the outside temperatures, the longer the minimum operating time. The type of route traveled is to be understood in particular as the speed profile. When driving in "stop-and-go" mode, the minimum operating time is longer than when driving constantly at higher speeds. In addition, in order to save fuel, modern vehicles are equipped with an automatic start-stop system, which switches off the combustion engine in "stop-and-go" mode when it is stationary, which further extends the minimum service life.

Studies have shown that in many cases a motor vehicle is not operated continuously for more than 10 minutes. As a result, the emitted exhaust gases are in many cases not or only partially after-treated, which leads to correspondingly high concentrations of pollutants, especially in large cities.

In order to counteract the high concentrations of pollutants, the “Euro 7 emissions standard” was issued. In order to be able to meet this emission standard, it is necessary to bring the catalytic converter of a motor vehicle with an internal combustion engine to the above operating temperature within 1 minute. The thermal energy contained in the exhaust gas is not sufficient for this, which is why the catalytic converter has to be actively heated.

For this purpose it is known to use electric heaters. However, to heat the catalytic converter from ambient temperature to the above-mentioned operating temperature, high power is required, which is in the range from 20 to 30 kW. The commonly used vehicle batteries quickly reach their limits, with hybrid vehicles being particularly affected.

In order to protect the vehicle batteries, the catalytic converter can be heated with the chemical energy contained in the fuel instead of electrical energy. However, a corresponding burner, with which the catalytic converter is heated to the operating temperature, requires only very small amounts of fuel. The corresponding mass flows are around 1 to 2 kg/h. In order to bring the catalytic converter up to the operating temperature in the most fuel-efficient way possible, it is therefore necessary to precisely regulate the smallest mass flows of fuel.

In principle, two different types of valves can be used, namely a seat valve on the one hand and a slide or piston valve on the other. However, seat valves have the disadvantage that they release a comparatively large flow cross-sectional area per stroke unit, so that they are not or only partially suitable for regulating the amounts of fuel required here with sufficient precision.

Controlling the smallest amounts of fuel is much easier to implement with a slide or piston valve. Here, the shut-off body designed as a piston is provided with a control groove which releases a larger or smaller cross-sectional flow area depending on the position of the piston in the valve. Due to the principle, however, slide or piston valves have a certain amount of leakage. If, for example, a motor vehicle were not moved for a long period of time, a large quantity of fuel could accumulate in an uncontrolled manner, which could cause problems when igniting. In order to remedy this situation, it is known to connect a poppet valve and a spool or piston valve in series. The poppet valve is used to seal a line without leakage, while the spool or spool valve is used to control mass or volume flow. However, the effort involved in providing them is relatively high here, since two components are required, which also require a corresponding amount of installation space. In addition, the seat valve and the slide or piston valve must be matched to one another in terms of control technology, which further increases the complexity.

The object of one embodiment of the present invention is to propose a flow control valve with which even small mass flows can be regulated without leaks and with sufficient precision. In addition, an embodiment of the invention is based on the object Specify method for operating such a flow control valve.

This object is achieved with the features specified in claims 1 and 14. Advantageous embodiments are the subject matter of the dependent claims.

• - mindestens einen Eingang und mindestens einen Ausgang,
• - einen mit dem Eingang fluidisch verbundenen ersten Druckraum,
• - einen mit dem Ausgang fluidisch verbundenen zweiten Druckraum, wobei der erste Druckraum entlang einer Längsachse axial versetzt zum zweiten Druckraum angeordnet ist,
• - einen Stößel, der entlang der Längsachse bewegbar gelagert und mittels einer bestrombaren Betätigungseinrichtung entlang der Längsachse bewegbar ist,
• - einen Ventilsitz, und
• - einen Kolben, welcher
  • ◯ entlang der Längsachse bewegbar gelagert und mittels des Stößels entlang der Längsachse zwischen einer ersten Endstellung und einer zweiten Endstellung bewegbar ist,
  • ◯ einen Durchtrittskanal bildet, der den ersten Druckraum und den zweiten Druckraum zumindest in der zweiten Endstellung fluidisch miteinander verbindet,
  • ◯ einen Dichtabschnitt aufweist, der in der ersten Endstellung am Ventilsitz anliegt und in der ersten Endstellung den ersten Druckraum fluidisch vom zweiten Druckraum trennt, und
  • ◯ eine Steuernut aufweist, die eine Strömungsquerschnittsfläche bereitstellt, welche den Durchtrittskanal und den ersten Druckraum oder den Durchtrittskanal und den zweiten Druckraum fluidisch miteinander verbindet, wenn sich der Kolben zwischen der ersten Endstellung und der zweiten Endstellung befindet, wobei die Größe der Strömungsquerschnittfläche in Abhängigkeit der Position des Kolbens zwischen der ersten Endstellung und der zweiten Endstellung veränderbar ist.

An embodiment of the invention relates to a flow control valve for controlling or regulating a mass flow of a fluid, comprising

• - at least one input and at least one output,
• - a first pressure chamber fluidically connected to the input,
• - a second pressure chamber fluidically connected to the outlet, the first pressure chamber being arranged axially offset along a longitudinal axis with respect to the second pressure chamber,
• - a plunger, which is mounted so that it can move along the longitudinal axis and can be moved along the longitudinal axis by means of an actuation device that can be energized,
• - a valve seat, and
• - a piston, which
  • ◯ is movably mounted along the longitudinal axis and can be moved by means of the plunger along the longitudinal axis between a first end position and a second end position,
  • ◯ forms a passage channel which fluidly connects the first pressure chamber and the second pressure chamber to one another at least in the second end position,
  • ◯ has a sealing section which rests against the valve seat in the first end position and fluidly separates the first pressure chamber from the second pressure chamber in the first end position, and
  • ◯ has a control groove which provides a flow cross-sectional area which fluidly connects the through-channel and the first pressure chamber or the through-channel and the second pressure chamber with one another when the piston is between the first end position and the second end position, the size of the flow cross-sectional area depending on the Position of the piston between the first end position and the second end position can be changed.

The piston has a sealing section on the one hand and a control groove on the other. With the sealing section, the flow control valve can be closed without leakage in the first end position. Consequently, the first end position can also be referred to as the closed position. With the control groove, the flow cross-sectional area through which the fluid must flow can be selected depending on the position of the piston between the first and the second end position. In this case, the fluid can in particular be fuel that is used to heat up a catalytic converter by means of a burner, the use of the flow control valve not being limited to a specific type of fluid. The proposed flow control valve therefore combines the advantages of a seat valve (leak-free sealing) with the advantages of a slide or piston valve (precise regulation of even the smallest mass flows). There is no need for coordination of control and regulation technology, as is necessary with seat valves and slide or piston valves connected in series. In addition, installation space can be saved since the flow control valve can be designed to be more compact than separate seat valves and slide or piston valves. Since only one valve has to be manufactured, a contribution is made to the resource-saving use of raw materials. With a sufficient quantity, cost advantages can also be expected.

According to a further embodiment, the control groove can have a depth that changes along the longitudinal axis. The depth of the control groove can change linearly, so that it forms a certain angle of inclination to the longitudinal axis. In this embodiment, the control groove can be manufactured particularly easily. However, it is just as possible to give the control groove a certain profile, so that the depth of the control groove does not change linearly. This can be desirable for technical control reasons.

In a further developed embodiment, the control groove can have a width that changes along the longitudinal axis. Here, too, the width of the control groove can change linearly or by means of a certain profile. Both the changing width and the changing depth of the control groove ensure that the flow cross-sectional area changes depending on the position of the piston between the first end position and the second end position. The mass flow can be set accordingly by the flow control valve.

In a further developed embodiment, the piston can be prestressed into the first end position by means of a first spring. As mentioned, the sealing section is in contact with the valve seat in the first end position. As a result, the flow control valve is closed without leakage. As also mentioned, the piston is displaced along the longitudinal axis with the aid of the ram by means of an actuation device that can be energized. In the event that the power supply fails for whatever reason, the first spring ensures that the flow control valve is closed sen is In particular, when the flow control valve is used to control or regulate a mass flow of a fuel with which a catalytic converter is heated to the operating temperature, the first spring ensures that the flow control valve is closed when the motor vehicle in question is switched off and not in operation. An uncontrolled accumulation and/or escape of fuel is avoided.

In a further embodiment, the ram can have a first end face and a second end face and a ram bore running between the first end face and the second end face, the first end face interacting with the piston to move the same and the ram bore being fluidically connected to the through-flow channel. In this case, a third pressure chamber can be provided, into which the tappet bore opens at the second end face. In this embodiment it is possible to set the same pressure in the first pressure chamber and in the third pressure chamber. As a result, the plunger only has to be moved against the biasing force exerted by the first spring, but not against a differential pressure. The actuating device can therefore either have smaller dimensions or be operated with a lower current. In addition, the ram can be accelerated faster, so that the control can be carried out faster and more dynamically.

A further developed embodiment can be characterized in that the tappet is prestressed against the piston by means of a second spring. The second spring supports the actuating device in moving the tappet, so that the tappet can also be accelerated more quickly as a result, which in turn leads to faster and more dynamic regulation. In addition, the ram is prevented from hitting the piston in an uncontrolled manner. Noise and damage occurring as a result are avoided. In addition, the constant contact of the piston on the ram ensures that there is always a flow of force between the piston and the ram.

According to a further embodiment, the flow control valve comprises a first screw plug for adjusting the pretensioning force of the first spring and/or a second screw plug for adjusting the pretensioning force of the second spring. The screw plug is used to set the first spring and piston in the flow control valve at a specific flow rate during assembly. The prestressing force of the second spring acting on the tappet and thus also on the piston can be adjusted with the second locking screw, with the prestressing force of the first spring and that of the second spring acting in opposite directions. The flow control valve can be calibrated in this way and guarantee a common reference point for operation in the vehicle and the parameter data stored there in order to be able to regulate the fluid volume precisely.

According to a further embodiment, a contact piston can be connected to the piston, the contact piston interacting with the first end face of the plunger. Depending on the configuration of the piston, the control groove can start from that piston end face which interacts with the tappet. In this respect, the end face in question can be damaged when the plunger is in contact with it. This damage, in turn, can also affect the control groove, which can change its shape. The change in shape can cause a change in flow cross-sectional area, which can adversely affect the control or regulation of mass flow through the flow control valve. The contact piston can be designed and arranged in such a way that the piston end face in question is protected, so that the above-mentioned influences on the control groove can be prevented.

According to a further embodiment, the contact piston can have a through bore which fluidly connects the passage channel and the tappet bore. The contact piston can be essentially tubular and therefore simple in design. This ensures that the pressures in the first pressure chamber and in the third pressure chamber can equalize.

In a further developed embodiment, the contact piston can have at least one further bore opening into the through-bore, which fluidly connects the through-bore to the control groove. Consequently, the through-channel is also fluidically connected to the further bores. In this embodiment, the contact piston is incorporated into the fluid flow path through the flow control valve. The structural design of the contact piston can be kept simple as a result.

In a further developed embodiment, the first pressure chamber and the second pressure chamber as well as the valve seat can be formed by an insert part that can be inserted into the flow control valve. The insert is also referred to as a "cartridge". The use of an insert significantly simplifies the production of the flow control valve, so that the production costs can be kept low.

A further embodiment can be designed in such a way that in the sealing section a sealing element ment is arranged, which has a relation to a sectional plane running through the longitudinal axis has a polygonal cross-section. In many cases, the sealing elements are designed as O-rings, which have a circular or elliptical cross section. Because of the circular or elliptical cross-section, the O-rings bear against the groove in question with a comparatively small contact surface, resulting in relatively strong deformation when the flow control valve is in the first end position and the O-ring is correspondingly loaded. If the flow control valve is to be opened, the deformations must first be overcome, which requires a certain stroke. However, this hub is then no longer available for controlling the mass flows, which has a negative effect on the dynamics and the accuracy of the control.

If the sealing element has a polygonal cross section, it can bear against the groove in question over a large area, as a result of which the deformation in the first end position can be significantly reduced. As a result, the flow control valve opens even with smaller strokes, which improves the accuracy and the dynamics of the control of the mass flows. In the case of sealing elements with a polygonal cross section, it is particularly advisable to arrange the groove in question either in the valve housing or on the piston, which increases design freedom.

In a further embodiment, the flow control valve can have a temperature sensor for determining the temperature of the fluid in the inlet. The viscosity and density of fluids are generally temperature dependent. Knowing the temperature of the fluid at the inlet can be taken into account when controlling the flow control valve and, in particular, when determining the axial position of the piston. As a result, the size of the flow cross-sectional area can be adjusted so that the required mass flow can be provided by the control valve regardless of the temperature of the fluid.

A further developed embodiment can be characterized in that the flow control valve has a first pressure sensor for determining the pressure of the fluid in the inlet. The mass flow of the fluid through the flow control valve depends on the pressure of the fluid. As already described for the temperature, the pressure that the fluid has in the inlet can be taken into account when controlling the flow control valve. As a result, the desired mass flow can be set independently of the pressure of the fluid in the inlet.

In a further embodiment, it may be appropriate for the flow control valve to have a second pressure sensor for determining the pressure of the fluid in the outlet. Atmospheric pressure usually prevails at the outlet. However, there can also be operating states in which there is a negative pressure at the outlet. As a result, a suction effect occurs, which in turn exerts an influence on the mass flow through the flow control valve. In the event that the flow control valve has both the first pressure sensor and the second pressure sensor, a differential pressure between the input and the output can be determined, which in turn can be taken into account when controlling the flow control valve, also with the aim of achieving the desired mass flow to set the flow control valve as precisely as possible.

• - Vorspannen des Kolbens in die erste Endstellung mittels der ersten Feder, so dass der Dichtabschnitt am Ventilsitz anliegt,
• - Bestromen der Betätigungseinrichtung zum Bewegen des Stößels entlang der Längsachse derart, dass
  • o der Kolben gegen die Vorspannkraft der ersten Feder entlang der Längsachse verschoben und der Dichtabschnitt vom Ventilsitz weg bewegt wird und
  • o die Steuernut den Durchtrittskanal und den ersten Druckraum oder den Durchtrittskanal und den zweiten Druckraum fluidisch miteinander verbindet, wobei
  • o die Größe der Strömungsquerschnittfläche der Steuernut in Abhängigkeit der Position des Kolbens zwischen der ersten Endstellung und der zweiten Endstellung mittels der Bestromung der Betätigungseinrichtung veränderbar ist.

One embodiment of the invention relates to a method for operating a flow control valve according to one of the previous embodiments, comprising the following steps:

• - Prestressing of the piston into the first end position by means of the first spring, so that the sealing section rests against the valve seat,
• - Energizing the actuating device for moving the plunger along the longitudinal axis in such a way that
  • o the piston is displaced along the longitudinal axis against the biasing force of the first spring and the sealing section is moved away from the valve seat and
  • o the control groove fluidly connects the through-channel and the first pressure chamber or the through-channel and the second pressure chamber with one another, wherein
  • o the size of the flow cross-sectional area of the control groove can be changed depending on the position of the piston between the first end position and the second end position by energizing the actuating device.

The technical effects and advantages that can be achieved with the proposed method correspond to those that have been discussed for the present flow control valve. In summary, it should be pointed out that with the present flow control valve it is possible to control or regulate even the smallest mass flows with sufficient accuracy without leakage occurring. It is not necessary to use spatially separate seat valves and slide or piston valves. Voting for control or regulation purposes can be omitted.

• 1 eine perspektivische Ansicht einer ersten Ausführungsform eines vorschlagsgemäßen Stromregelventils,
• 2 eine Seitenansicht des in 1 dargestellten Stromregelventils,
• 3 eine Schnittdarstellung durch das Stromregelventil entlang der in 2 definierten Schnittebene A-A,
• 4 eine vergrößerte Darstellung des in 3 definierten Ausschnitts B,
• 5 eine vergrößerte Darstellung des in 4 definierten Ausschnitts C,
• 6 eine vergrößerte Darstellung einer zweiten Ausführungsform eines Stromregelventils in Anlehnung an die in 5 gewählte Darstellung,
• 7A bis 7D verschiedene Ausführungen der Steuernut
• 8A und 8B eine vergrößerte Darstellung eines drittes Ausführungsbeispiels in Anlehnung an die in 4 gewählte Darstellung, und
• 9A und 9B eine vergrößerte Darstellung eines vierten Ausführungsbeispiels in Anlehnung an die in 4 gewählte Darstellung.

Exemplary embodiments of the invention are described below with reference to FIG the accompanying drawings explained in more detail. Show it

• 1 a perspective view of a first embodiment of a proposed flow control valve,
• 2 a side view of the in 1 illustrated flow control valve,
• 3 a sectional view through the flow control valve along the in 2 defined cutting plane AA,
• 4 an enlarged view of the in 3 defined section B,
• 5 an enlarged view of the in 4 defined section C,
• 6 an enlarged view of a second embodiment of a flow control valve based on in 5 selected representation,
• 7A until 7D different versions of the control groove
• 8A and 8B an enlarged view of a third embodiment based on in 4 selected representation, and
• 9A and 9B an enlarged view of a fourth embodiment based on in 4 selected representation.

In the 1 and 2 1 shows an exemplary embodiment of a flow control valve 10 according to the present invention using a perspective illustration or using a side view. The flow control valve 10 has a valve housing 12 with an inlet 14 and an outlet 16 . A supply line, not shown here, can be connected to the input 14, with which a fluid, for example fuel, can be supplied from a pressure source to the flow control valve 10. Correspondingly, a discharge line (also not shown) can be connected to the outlet 16, with which the fluid that has flowed through the flow control valve 10 can be passed on to a consumer, for example a burner. Furthermore, a temperature sensor 18 is attached to the valve housing 12, with which the temperature of the fluid in the inlet 14 can be determined. Furthermore, a first pressure sensor 20 is fastened to the valve housing 12 and is used to determine the pressure of the fluid in the inlet 14 . In addition, the flow control valve 10 includes a second pressure sensor 22 which can be used to determine the pressure of the fluid in the outlet 16 . In addition, in 1 an actuator 24 is shown, which can be energized. Accordingly, in 1 Power connections 26 recognizable. The exact function of the actuating device 24 is discussed in more detail below.

3 shows a sectional view of the 1 and 2 Flow control valve 10 shown along the 2 defined cutting plane AA. It can be seen that the valve housing 12 is designed as a valve block 28 and is therefore solid. A sleeve-shaped insert part 30 is inserted into the valve block 28 , for which purpose the valve block 28 has a corresponding valve block bore 32 . A first pressure chamber 34 is arranged inside the insert part 30 and is fluidically connected to the inlet 14 by means of an inlet bore 36 . The term “fluidically connected” can be understood below to mean that a fluid can flow between the fluidically connected components without these necessarily being mechanically connected to one another.

A piston 38 is slidably mounted within the insert part 30 along a longitudinal axis L defined by the valve block bore 32 . As in particular from the 4 it is recognizable which the in 3 defined section B is enlarged, the piston 38 is provided with a sealing section 40, in which a sealing element 41 is arranged, which is designed as an O-ring 42 in the illustrated embodiment. The piston 38 is pressed against a valve seat 46 formed by the insert part 30 by a first spring 44 . The piston 38 is designed in such a way that the sealing section 40 rests against the valve seat 46, in this case with the O-ring 42. Alternatively, a metallic sealing seat (not shown) can also be provided, in which the piston 38 has an outer cone , which can be pressed against an inner cone of the insert part 30. The first spring 44 is supported on a first screw plug 48 which is screwed into the insert part 30, as in particular from FIG 3 recognizable. The prestressing of the first spring 44 can be adjusted with the first locking screw 48 . The insert part 30 is covered with a cover 49 at the left end.

Referring to the 4 For example, the piston 38 is provided with a through-channel 50 which includes a blind hole 52 and a number of radial holes 54 running perpendicularly to the longitudinal axis L in the area of the closed end. A contact piston 56 is connected to the piston 38 at the free end of the passage channel 50 . The contact piston 56 is equipped with a through hole 58 which is approximately aligned with the through-channel 50 . In addition, the contact piston 56 has a number of further bores 60 which run perpendicularly to the longitudinal axis L and open into the through bore 58 . How in particular from the 5 recognizable which the in 4 Marked section C shows enlarged, the piston 38 has a control groove 62 in the area of the end at which the contact piston 56 is connected to the piston 38, which starts from a piston end face 64 of the piston 38.

the 7A until 7D show some embodiments of this cam 62. The 7A until 7B are a basic plan view of the control groove 62 and the piston 38, while the 7C and 7D show a basic sectional view through the control groove 62 and consequently through the piston 38. From the 7A and 7B it can be seen that the control groove 62 can have a width W that changes along the longitudinal axis L. While the width W of the in 7A The control groove 62 shown changes linearly along the longitudinal axis L, the width W of the in 7B shown control groove 62 along the longitudinal axis L by means of a non-linear relationship.

In the 7C and 7D it is shown that the depth T of the control groove 62 along the longitudinal axis L can change. Again, the depth changes in the in 7C The control groove 62 shown linearly along the longitudinal axis L, while the depth T of the in 7D shown control groove 62 changes along the longitudinal axis L with a non-linear relationship. The control groove 62, which in 5 is shown essentially corresponds to that shown in 7C is shown.

From the 5 It can also be seen that the contact piston 56 is constructed in the shape of a mushroom and forms an edge 66 that protrudes radially outwards. This rim 66 projects along the longitudinal axis L beyond the piston end face 64 so that an intermediate space 68 is formed between the piston 38 and the rim 66 . This intermediate space 68 adjoins the further bores 60 of the contact piston 56 radially outwards.

In particular, referring to the 4 and 5 a second pressure chamber 70 is arranged in the insert part 30, which is fluidically connected to the outlet 16 by means of an outlet bore 72, which is particularly evident from the 3 emerges.

From the 3 also shows that the actuating device 24 comprises an electromagnet 74 with which a plunger 76 mounted concentrically to the longitudinal axis L can be displaced along the longitudinal axis L. The plunger 76 has a first end face 78, which in particular 5 is clearly visible, and which can be brought to the contact piston 56 to the plant. In addition, the plunger 76 has a second end face 80, which in 3 is shown. A tappet bore 82 runs between the first end face 78 and the second end face 80 and opens into a third pressure chamber 83 at the second end face 80 . From the 5 It can be seen that the tappet bore 82 in the region of the first end face 78 is fluidly connected to the through bore 58 of the contact piston 56 and consequently also to the through-channel 50 of the piston crown. Beyond that is off 3 recognizable that a second spring 84 is at least partially arranged in the third pressure chamber 83 and biases the plunger 76 against the contact piston 56 . The second spring 84 is supported on a second locking screw 86, with which the prestressing force of the second spring 84 can be adjusted.

Referring to the 2 it is clear that two transverse bores 90 connect the tappet bore 82 to an armature space 92 . Furthermore, the electromagnet 74 has a cone 94, an armature 96, a copper coil 98 and a non-magnetic sleeve. The copper coil 98 can also be made of any other suitable material. In this way it is achieved that the magnetic field is directed in such a way that the magnetic force applied by the electromagnet can be transmitted to the tappet 76 as effectively as possible and can be converted into a linear movement of the tappet.

The flow control valve 10 is operated in the following manner: In the de-energized state, which in the 3 until 5 is shown, the piston 38 is pressed with the first spring 44 against the valve seat 46, so that the piston 38 assumes a first end position in which the control valve is sealed in particular with the O-ring 42 without leakage. It is therefore a "normally closed" flow control valve 10. The second spring 84 presses the plunger 76 against the contact piston 56. Since the biasing force exerted by the second spring 84 is less than the biasing force exerted by the first spring 44, the Piston 38 is not moved away from the valve seat 46. In the first end position, the fluid which is present at the inlet 14 with a specific inlet pressure can only flow via the inlet bore 36 into the first pressure chamber 34 and up to the valve seat 46, but no further. If the actuating device 24 is now energized, the plunger 76 is moved towards the contact piston 56 and towards the piston 38, as a result of which the piston 38 together with the contact piston 56 counteracts the direction of action of the prestressing force of the first spring 44 and counteracts the differential pressure acting on the valve seat 46 between the Input 14 and the output 16 is shifted. Based on the in the 3 until 5 selected representation, the plunger 76, the contact piston 56 and the piston 38 are moved to the left. As a result, the sealing portion 40 is moved away from the valve seat 46. As soon as the radial bores 54 pass over the valve seat 46 are pushed out into the first pressure chamber 34, the first pressure chamber 34 and the through-channel 50 are fluidically connected to one another, as a result of which the fluid flows from the first pressure chamber 34 through the through-channel 50 to the through-bore 58 and further through the further bores 60 to the intermediate space 68 between the piston 38 and the edge 66 of the contact piston 56 can flow. At the same time, the fluid also continues to flow through the tappet bore 82 and the transverse bores 90 into the armature chamber 92 and into the third pressure chamber 83. This ensures that the hydraulic axial forces are compensated and the electromagnet 74 only works against the force of the first spring 44. The fluid can then flow into the control groove 62 . Out of 5 it can be seen that a certain overlap D remains between the end of the control groove 62 pointing to the second pressure chamber 70 and a wall 88 of the second pressure chamber 70 in the first end position. This overlap D ensures that no fluid flows into the outlet bore 72 when the valve seat 46 opens.

The fluid can only flow completely through the control groove 62 and into the second Pressure chamber 70 occur. From there it can flow on to the outlet 16 via the outlet bore 72 .

As already mentioned, the ram 76 has the ram bore 82 which runs between the first end face 78 and the second end face 80 . Consequently, the fluid can enter the tappet bore 82 from the through bore 58 of the contact piston 56 and from there can flow further into the armature chamber 92 and the third pressure chamber 83 . This ensures that the pressure in the third pressure chamber 83 corresponds to the pressure in the first pressure chamber 34 . As a result, the plunger 76, the contact piston 56 and the piston 38 do not have to be moved against a differential pressure once fluid communication between the first pressure chamber 34 and the third pressure chamber 83 has been established. In particular from the 4 it can be seen that a certain distance along the longitudinal axis L remains between the valve seat 46 and the radial bores 54 when the piston 38 is in the first end position. This distance is smaller in the first end position than the already mentioned overlap D. As a result, the pressure equalization between the first pressure chamber 34 and the third pressure chamber 83 does not take place immediately after the movement of the piston 38 away from the valve seat 46, but first the O-ring 42 moves out of the sealing seat 46. Rather, the piston 38 must be moved by a certain distance in order to be able to establish the pressure equalization. As long as this pressure equalization has not yet been established, the piston 38, the contact piston 56 and the plunger 76 must be moved against the differential pressure, for which purpose the actuating device 24 can be subjected to a “peak current”. As soon as the pressure equalization has been established, the piston 38, the contact piston 56 and the plunger 76 only have to be moved against the difference between the biasing force of the first spring 44 and the biasing force of the second spring 84. This requires a significantly lower current. In the position of the piston 38 in which the pressure equalization has already been established, however, the overlap D has been reduced but has not yet been completely eliminated. Therefore, no fluid can yet flow from the control groove 62 into the second pressure chamber 70 .

In particular, referring to the 5 until 7D It can be seen that, depending on the position of the piston 38, the size of the flow cross-sectional area that the control groove 62 releases changes. As long as the control groove 62 does not protrude into the second pressure chamber 70 , it can be assumed that the fluid cannot flow from the control groove 62 into the second pressure chamber 70 . The further the control groove 62 protrudes into the second pressure chamber 70, the greater the flow cross-sectional area released by the control groove 62 and consequently the mass flow. Accordingly, the mass flow of the fluid through the flow control valve 10 can be adjusted by means of the position of the piston 38, for which purpose the actuating device 24 is energized to a greater or lesser extent. The biasing force of the first spring 44 ensures that the piston 38 in the direction of the valve seat 46, in the 3 until 5 to the right. If the piston 38 so far against the direction of action of the first spring 44, in the 3 until 5 has been shifted to the left, so that the fluid can flow directly from the intermediate space 68 between the piston 38 and the edge 66 of the contact piston 56 into the second pressure chamber 70, the control groove 62 loses its influence on the mass flow of the fluid through the flow control valve 10. In In this case, the piston 38 is in a second end position. A very high mass flow can be set in the second end position. If the energization of the actuating device 24 is removed, the first spring 44 pushes the piston 38 back into the first end position.

The mass flow of the fluid through the flow control valve 10 is dependent not only on the size of the flow cross-sectional area released by the control groove 62, but also, among other things, on the temperature and the pressure of the fluid in the inlet 14. For this reason, the temperature of the fluid in the inlet 14 can be determined with the temperature sensor 18 and the pressure of the fluid in the inlet 14 with the first pressure sensor 20. Atmospheric pressure is usually present at the outlet 16, so that the pressure of the fluid in the inlet 14 can also be used to determine a pressure difference. Depending on the area of application of the pressure control valve, however, it can also happen that there is a negative pressure at the outlet 16 and suction effects therefore occur. The pressure of the fluid in the outlet 16 can be determined with the second pressure sensor 22 , so that a differential pressure between the inlet 14 and the outlet 16 can also be determined in the event of a negative pressure at the outlet 16 . The temperature measured by the temperature sensor 18 and the pressures of the fluid measured by the first pressure sensor 20 and the second pressure sensor 22 can be taken into account when controlling the flow control valve 10 . The energization of the actuating device 24 can be selected in such a way that the desired mass flow through the pressure control valve is set even with changing temperature and pressure conditions.

6 shows a second embodiment of a flow control valve 10 based on in 5 selected representation. The essential structure of the flow control valve 10 according to the second embodiment corresponds largely to that of the first embodiment. The manner in which the two flow control valves 10 are operated is also largely the same. However, if one compares the control grooves 62, one finds that the control groove 62 according to the 6 shown flow control valve 10 is larger than the control groove of in 5 illustrated flow control valve 10. In particular, the depth T (cf. 7A until 7D ) greater. The mass flow of the fluid that can flow through the control groove 62 is correspondingly greater, so that the 6 shown flow control valve 10 is suitable for heating larger catalysts that are used for example in trucks or construction machinery, while in the 1 until 5 shown flow control valve 10 is suitable for cars.

It should also be noted that in 6 a compensating ring 102 can be seen, with which the position of the contact piston 56 with respect to the longitudinal axis L can be adjusted. Various compensating rings 102 can be used, which have different extensions along the longitudinal axis L. Manufacturing inaccuracies can be compensated for with the compensation ring 102.

With the screw plug 48, the first spring 44 and the piston 38 in the flow control valve 10 are set to a specific flow rate at a specific flow during assembly. The flow control valve 10 can be calibrated in this way and guarantee a common reference point for operation in the vehicle and the parameter data stored there in order to be able to control the fuel quantity precisely.

In the 8A and 8B is a third embodiment of a flow control valve 10 based on in 4 Selected representation shown enlarged. In 8A the flow control valve 10 is in the first end position, while it is in 8B located between the first end position and the second end position. The essential difference lies in the design of the sealing element 41, which in the third exemplary embodiment shown here is not designed as an O-ring 42, but which has a polygonal cross section in relation to a sectional plane running through the longitudinal axis L. The sealing element 41 is arranged in a sealing element groove 43 arranged in the piston 38 .

As in particular from the 8B shows, the sealing element 41 has a rectangular cross section. In the first end position (see 8A ) the sealing element 41 rests against the valve seat 46 and is correspondingly deformed. In order to allow the deformation, clearances are provided radially outside of the valve seat 46 .

In the 9A and 9B is a fourth embodiment of a flow control valve 10 based on in 4 Selected representation shown enlarged. In 9A the flow control valve 10 is in the first end position, while it is in 9B located between the first end position and the second end position. In the fourth exemplary embodiment as well, the sealing element 41 has a polygonal cross section with respect to a sectional plane running through the longitudinal axis L. In this case, the sealing element 41 is provided with a pentagonal cross section. In contrast to the third exemplary embodiment of the flow control valve 10 , the sealing element 41 is arranged in a sealing element groove 43 located in the insert part 30 . Due to the pentagonal cross section, the sealing element 41 forms a conical sealing surface, with which the sealing element 41 comes to rest in the first end position with a corresponding conical sealing surface of the piston 38 (see FIG 9A ). In the first end position, the piston 38 is in contact with a contact surface 104 of the insert part 30 . This prevents the sealing element 41 from being subjected to excessive stress and correspondingly severe deformation, which in extreme cases could lead to the sealing element 41 being destroyed.

Due to the polygonal cross section of the sealing element 41, it rests over a large area in the sealing element groove 43, which is why the deformations of the sealing element 41 that occur in the first end position are kept small in comparison to the O-ring 42. Due to the smaller deformations, the flow control valve 10 already opens with a smaller stroke than is the case in comparison to the O-ring 42, in which the deformations first have to be overcome in order for the flow control valve 10 to open.

Reference List

10

flow control valve

12

valve body

14

Entry

16

Exit

18

temperature sensor

20

first pressure sensor

22

second pressure sensor

24

actuating device

26

power connection

28

valve block

30

insert part

32

valve block bore

34

first pressure room

36

entrance hole

38

Pistons

40

sealing section

41

sealing element

42

o ring

43

sealing element groove

44

first spring

46

valve seat

48

first locking screw

49

lid

50

passageway

52

blind hole

54

radial bore

56

contact plunger

58

through hole

60

further drilling

62

control groove

64

piston face

66

edge

68

space

70

second pressure room

72

exit hole

74

electromagnet

76

pestle

78

first face

80

second face

82

tappet bore

83

third pressure room

84

second spring

86

second locking screw

88

wall

90

cross bore

92

anchor room

94

cone

96

anchor

98

copper coil

100

sleeve

102

balancing ring

104

contact surface

D

overlap

L

longitudinal axis

T

depth

W

Broad

Claims (16)

Flow control valve (10) for controlling or regulating a mass flow of a fluid, comprising - at least one inlet (14) and at least one outlet (16), - a first pressure chamber (34) fluidically connected to the inlet (14), - one to the outlet (16) fluidically connected second pressure chamber (70), the first pressure chamber (34) being arranged axially offset relative to the second pressure chamber (70) along a longitudinal axis (L), - a tappet (76) which can be moved along the longitudinal axis (L). is mounted in the valve housing (12) and can be moved along the longitudinal axis (L) by means of an actuation device (24) that can be energized, - a valve seat (46), and - a piston (38) which can be moved along the longitudinal axis (L) in the valve housing ( 12) and mounted by means of the plunger (76) along the longitudinal axis (L) between a first end position and a second end position, o forms a through-channel (50) which fluidly connects the first pressure chamber (34) and the second pressure chamber (70) to one another at least in the second end position, o has a sealing section (40) which in the in the first end position rests against the valve seat (46) and in the first end position fluidly separates the first pressure chamber (34) from the second pressure chamber (70), and o has a control groove (62) which provides a flow cross-sectional area which separates the passage channel (50) and the fluidly connects the first pressure chamber (34) or the through-channel (50) and the second pressure chamber (70) to one another when the piston (38) is between the first end position and the second end position, the size of the flow cross-sectional area depending on the position of the piston (38) can be changed between the first end position and the second end position. Flow control valve (10) after claim 1 , characterized in that the control groove (62) has a depth (T) that varies along the longitudinal axis (L). Flow control valve (10) according to one of Claims 1 or 2 , characterized in that the control groove (62) has a width (W) that varies along the longitudinal axis (L). Flow control valve (10) according to one of the preceding claims, characterized in that the piston (38) is prestressed into the first end position by means of a first spring (44). Flow control valve (10) according to one of the preceding claims, characterized in that - the tappet (76) o has a first end face (78) and a second end face (80) and o one between the first end face (78) and the second end face (80 ) running tappet bore (82), wherein the first end face (78) interacts with the same to move the piston (38) and the tappet bore (82) is fluidically connected to the through-channel (50), and - a third pressure chamber (83) is provided is, in which the tappet bore (82) at the second end face (80) opens. Flow control valve (10) according to one of the preceding claims, characterized in that the tappet (76) is prestressed against the piston (38) by means of a second spring (84). Flow control valve (10) after claim 6 , characterized in that the flow control valve (10) comprises a first screw plug (48) for adjusting the biasing force of the first spring (44) and / or a second screw plug (86) for adjusting the biasing force of the second spring (84). Flow control valve (10) according to one of the preceding claims, characterized in that a contact piston (56) is connected to the piston (38), the contact piston (56) interacting with the first end face (78) of the tappet (76). Flow control valve (10) after claim 8 , characterized in that the contact piston (56) has a through bore (58) which fluidly connects the through-channel (50) and the tappet bore (82). Flow control valve (10) after claim 9 , characterized in that the contact piston (56) has at least one further bore (60) which opens into the through bore (58) and fluidically connects the through bore (58) to the control groove (62). Flow control valve (10) according to one of the preceding claims, characterized in that the first pressure chamber (34) and the second pressure chamber (70) and the valve seat (46) are formed by an insert part (30) which can be inserted into the valve housing (12). Flow control valve (10) according to one of the preceding claims, characterized in that a sealing element (41) is arranged in the sealing section (40) which has a polygonal cross-section in relation to a sectional plane running through the longitudinal axis (L). Flow control valve (10) according to one of the preceding claims, characterized in that the flow control valve (10) has a temperature sensor (18) for determining the temperature of the fluid in the inlet (14). Flow control valve (10) according to one of the preceding claims, characterized in that the flow control valve (10) has a first pressure sensor (20) for determining the pressure of the fluid in the inlet (14). Flow control valve (10) according to one of the preceding claims, characterized in that the flow control valve (10) has a second pressure sensor (22) for determining the pressure of the fluid in the outlet (16). Method for operating a flow control valve (10) according to one of Claims 4 until 15 , comprising the following steps: - biasing the piston (38) to the first extreme position tion by means of the first spring (44) so that the sealing section (40) rests against the valve seat (46), - energizing the actuating device (24) to move the plunger (76) along the longitudinal axis (L) in such a way that o the piston ( 38) is displaced along the longitudinal axis (L) against the prestressing force of the first spring (44) and the sealing section (40) is moved away from the valve seat (46) and o the control groove (62) opens the passage channel (50) and the first pressure chamber (34 ) or fluidically connects the through-channel (50) and the second pressure chamber (70), wherein o the size of the flow cross-sectional area of the control groove (62) depends on the position of the piston (38) between the first end position and the second end position by means of the energization of the Actuating device (24) can be changed.

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