DE102022207388A1 - Method for operating a fluid storage system and fluid storage system that can be operated with such a method - Google Patents

Abstract

The invention relates to a method for operating a fluid storage system (2), which has at least one fluid tank (4) in which a fluid can be stored or is stored under pressure, at least one valve unit (6) which is arranged on the fluid tank (4) and the a supply path (10), along which fluid can flow from the fluid tank (4) through the valve unit (6) in the direction of a consumer (12), and a refueling path (14) through which fluid passes for filling the fluid tank (4). the valve unit (6) can flow into the fluid tank (4), at least one controllable valve means (16) being arranged in the supply path (10), which moves from a closed functional position, in which flow through the valve means (16) is blocked, into a Open functional position can be transferred, in which fluid can flow through the valve means (16), and which comprises at least one control unit (18), through which the valve means (16) of the valve unit (6) can be controlled for opening and closing and through which at least when detecting the end of a refueling process of the fluid tank (4), a valve means de-icing procedure is carried out, in which the valve means (16) of the valve unit (6) is transferred from the closed functional position to the open functional position and back again to the closed functional position .

Description

The invention relates to a method for operating a fluid storage system and a fluid storage system that can be operated with such a method.

Fluid storage systems are known, for example, in hybrid vehicles. These can include a fluid tank in which a fluid can be stored. The fluid tank may comprise a hydrogen hydrogen tank and the fluid may comprise hydrogen. The fluid can be stored in the fluid tank under a high pressure of up to 900 bar.

When refueling the fluid tank, fluid is filled via a refueling path of a valve unit. The fluid covers temperatures of up to -40°C.

When filling the fluid tank of the fluid storage system of the motor vehicle, it can never be completely ruled out that individual components of the valve unit cool down due to the low temperatures of the fluid in such a way that residual moisture present in the valve unit can freeze and, for example, a valve means of the valve unit becomes stuck or its tightness in one closed functional position can have a negative impact.

As a result, quick opening and secure, tight closing immediately after filling the fluid tank with fluid cannot be guaranteed.

One object of an exemplary embodiment of the invention is to propose a method for operating a fluid storage system and a fluid storage system that can be operated with such a method, in which a high level of tightness of the valve unit and mobility of the valve means can be guaranteed after a refueling process.

This object is achieved by a method for operating a fluid storage system, which has at least one fluid tank in which a fluid can be stored or stored under pressure, which has at least one valve unit which is arranged on the fluid tank and which has a supply path along which the fluid from the fluid tank passes through the valve unit can flow in the direction of a consumer, and comprises a refueling path through which fluid for filling the fluid tank can flow through the valve unit into the fluid tank, at least one controllable valve means being arranged in the supply path, which is from a closed functional position in which flow through of the valve means is blocked, can be moved into an open functional position in which fluid can flow through the valve means, and which comprises at least one control unit through which the valve means of the valve unit can be controlled for opening and closing and through which at least when detecting the completion of a refueling process of the fluid tank, a valve means de-icing procedure is carried out, in which the valve means of the valve unit is transferred from the closed functional position to the open functional position and back again to the closed functional position.

The fact that a valve means de-icing procedure is carried out when detecting the end of a refueling process of the fluid tank ensures that fluid flows through the valve means. By activating the valve means to transfer from a closed functional position to an open functional position and back again, the risk of residual moisture freezing in the area of the valve means is reduced.

In addition, the fluid that flows through the valve unit over the refueling path during refueling and usually has a low temperature, for example -40 ° C, is stored in the fluid tank and placed under high pressure there. This high pressure can be up to 900 bar, for example. This causes the previously cold fluid to warm up to 30 to 50°C. When transferring the valve means in the supply path from the closed functional position to the open functional position, heated fluid flows from the fluid tank through the valve means and can heat them in such a way that icing of residual moisture on the valve means is released, in particular melted away.

The fluid can be any fluid that can be consumed by a consumer. For example, the consumer can be a brake fuel cell. In this case, the fluid can be hydrogen.

In principle, it is conceivable that the at least one valve means of the valve unit is transferred from the open functional position back to the closed functional position after predetermined time intervals have elapsed. It proves to be advantageous if at least one sensor means is functionally assigned to the control unit, through which an actual pressure of the fluid on the downstream side of the valve unit can be detected, with the control unit detecting a pressure drop in the actual pressure of the fluid on the downstream side of the Valve unit is detected since the valve means is transferred to the closed functional position and the valve means is controlled by the closed radio tion position is transferred to the open functional position when the pressure drop detected by the control unit reaches or exceeds a value stored in the control unit.

In such a case, a pressure difference can be generated, through which a flow velocity of the fluid through the valve unit is so high, at least in the initial phase, i.e. after the immediate transfer from the closed functional position to the open functional position, that stuck particles are loosened and carried away by the fluid from the valve unit become. The pressure drop can be, for example, 30 bar.

Because the control unit detects the pressure drop in the actual pressure, the opening and closing of the valve unit cannot be time-dependent, but rather pressure-dependent.

Embodiments of the method are conceivable in which a valve means of the valve unit is transferred from the closed functional position to the open functional position and back again only once in the course of the valve means de-icing procedure. In order to be able to ensure improved de-icing, it proves to be advantageous if, when carrying out the valve means de-icing procedure, the valve means of the valve unit is transferred from the closed functional position to the open functional position and back again to the closed functional position at least twice, in particular at least three times becomes.

When the valve means is transferred to the open functional position, pressure equalization occurs between the consumer side and the fluid tank side of the valve means. In order to design the valve means de-icing procedure in a time-efficient manner, a further development of the method provides that in the valve means de-icing procedure, the valve means after being transferred from the closed functional position to the open functional position after an open time period has elapsed, in particular after a maximum of 2 Seconds, in particular after a maximum of 5 seconds, in particular after a maximum of 10 seconds, is returned to the closed functional position.

The method, in particular the de-icing procedure, can be carried out when the fuel cell is starting and/or can be carried out when the fuel cell is switched off after refueling. During the shutdown process, the fuel cell can be in a run-on mode with the engine switched off.

Embodiments of the method are conceivable in which the valve defrosting procedure is carried out once or several times and the method is then ended. However, in order to be able to ensure that the at least one valve means closes correctly after the valve means de-icing procedure has been completed, it proves to be advantageous if in the control unit there is a TARGET pressure range on the downstream side of the valve unit when the functional position of the valve means is closed after a Time period after completion of the valve means de-icing procedure is stored, wherein a pressure drop in the actual pressure of the fluid on the downstream side of the valve unit is detected by the control unit and a new run through of the valve means de-icing procedure is initiated by the control unit when the ACTUAL pressure recorded by the control unit is above the TARGET pressure range after the period of time has elapsed.

When the valve means are closed and the fuel cell consumes fluid, the ACTUAL pressure drops by a certain amount within the period of time. If one of the valve means is not tight, the actual pressure does not drop or only drops very slowly. This can be interpreted by the control unit in such a way that at least one of the valve means is leaking.

If the control unit detects that the ACTUAL pressure exceeds the TARGET pressure range after the period of time has elapsed, this indicates that the valve means of the valve unit is not completely sealed. As a result, fluid can still flow through the valve means of the valve unit, whereby a pressure drop in the ACTUAL pressure after the period of time has elapsed is too small to be in the TARGET pressure range.

The valve means can basically comprise any valve means that can be controlled by the control unit and can be moved from the closed functional position to the open functional position and back. The method can be carried out simply and cost-effectively if the at least one valve means comprises a solenoid valve, which can be converted into the open functional position by the control unit by electrically energizing the closed functional position and which can be converted back into the closed functional position by the control unit or in the de-energized state State is automatically transferred to the closed functional position.

In this case, the valve means can be transferred from the closed functional position to the open functional position by energizing it and is automatically closed in the de-energized state.

In addition, de-icing of the valve means can be further improved if the valve means de-icing procedure involves increasing and/or a Lowering the mass flow of the fluid flowing through the valve means of the valve unit.

In addition, in a further development of the last two embodiments, it is conceivable that the increasing and/or lowering of the pressure and/or the mass flow rate of the fluid flowing through the at least one valve means occurs once or at least twice.

The measures described above, namely by increasing and/or lowering the pressure and/or the mass flow rate of the fluid flowing through the at least one valve means, can improve the removal of particles, in particular frozen residual moisture, from the valve means.

In principle, it is conceivable that the motor vehicle and the fluid storage system only comprise a single fluid tank. In addition, in one embodiment of the fluid storage system it is provided that the fluid storage system comprises at least two, in particular at least three, valve units, each of which is arranged on its own fluid tank or on a common fluid tank, and that the fluid storage system comprises at least one distribution unit into which the at least two valve units, in particular at least three valve units, open into a distribution section of the distribution unit, through which the flowing fluid can be passed on to a consumer and in which the sensor means is arranged in the distribution section, the actual pressure of the fluid detected by the sensor means in the distribution section of the distribution unit is recorded.

All three fluid tanks can be filled with fluid via the distributor section and can be brought into fluid connection with a common consumer via the distributor section.

If the sensor means is arranged in the distributor section of the distributor unit, the fluid storage system can be designed with reduced components. In such a case, one and the same sensor means can be used to check and control the valve means.

In a further development of the last-mentioned embodiment, it proves to be advantageous if the valve means de-icing procedure involves a joint and simultaneous or a separate and successive transfer from the closed functional position to the open functional position and back again to the closed functional position of the valve means of the at least two valve units , in particular the valve means of the at least three valve units, wherein after a valve means of a valve unit has been transferred from the open functional position to the closed functional position, a valve means of a further valve unit is transferred from the open functional position to the closed functional position, or if the valve means de-icing Procedure comprises a separate and successive passage through the valve means de-icing procedure of the valve means of the at least two valve units, in particular the valve means of the at least three valve units, wherein after completion of the valve means de-icing procedure of one valve unit with the valve means de-icing procedure of another Valve unit is started.

If, as part of the valve means de-icing procedure, all valve means are transferred together and simultaneously from the closed functional position to the open functional position, the valve means de-icing procedure can be carried out within a short time. If, as part of the valve means de-icing procedure, the individual valve means are transferred back separately and one after the other from the closed functional position to the open functional position, it is easier to determine whether and which valve means does not contain sufficient tightness.

In this case, it is conceivable, for example, that the valve means is first transferred from the closed functional position to the open functional position and back again by a first valve unit and then directly followed by a valve means of another valve unit.

In addition, only a single valve means of a valve unit can be transferred from the closed functional position to the open functional position and back again several times before a valve means of another valve unit is transferred several times from the closed functional position to the open functional position. The valve means of the valve units that are not or are not currently undergoing the valve means de-icing procedure are in the closed functional position.

In principle, it is conceivable that after the valve means has been transferred to the closed functional position, the valve means de-icing procedure of the next valve unit begins immediately. However, in order to be able to produce a sufficient pressure drop between the valve units that are in fluid communication with one another on the consumer side of the valve units, it proves to be advantageous if the valve means de-icing procedure involves a separate and successive passage through the valve means de-icing procedure of the valve means of the at least two Valve units, especially the Valve means of the at least three valve units, and if after completion of the valve de-icing procedure of a valve unit and the beginning of the valve de-icing procedure of a further valve unit, a transition period of time, in particular at least two seconds, in particular at least five seconds, in particular at least ten seconds , lies.

In addition, the object is achieved by a fluid storage system with at least one fluid tank, in which a fluid can be stored or stored under pressure, with at least one valve unit which is arranged on the fluid tank and which has a supply path along which fluid from the fluid tank through the valve unit in Direction of a consumer can be flowed, as well as a refueling path through which fluid for filling the fluid tank can flow through the valve unit into the fluid tank, at least one controllable valve means being arranged in the supply path, which can flow from an open functional position in which fluid can flow through the valve means is, can be moved into a closed functional position in which flow through the valve means is blocked, and with at least one control unit through which the valve means of the valve unit can be controlled for opening and closing, the fluid storage system being operable using a method with the aforementioned steps .

In addition, it proves to be advantageous if the fluid storage system comprises at least three valve units and at least one distribution unit, which comprises a distribution section into which the three distribution units open and in which a sensor means is arranged.

Finally, it proves to be advantageous if at least one of the valve means of the valve unit comprises a solenoid valve which can be moved by the control unit from the closed functional position to the open functional position and back again to the closed functional position.

One or more check valves can be provided in the second flow path, which are opened when the fluid tank is filled by the valve unit and prevent a backflow from the fluid tank against the inflow direction of the refueling path.

Further features, details and advantages of the invention result from the attached patent claims, from the graphic representation and subsequent description of a preferred embodiment of the fluid storage system and the method.

• 1 Eine schematische Darstellung eines Fluidspeichersystems;
• 2 Eine Detailansicht einer Ventileinheit eines Fluidtanks des Fluidspeichersystems gemäß 1;
• 3 Ein schematisches Ablaufdiagramm eines erfindungsgemäßen Verfahrens;
• 4 Ein graphischer Druckverlauf des IST-Drucks des Fluids in Abhängigkeit der Funktionsstellung der Ventilmittel der Ventileinheiten.

In the drawing shows:

• 1 A schematic representation of a fluid storage system;
• 2 A detailed view of a valve unit of a fluid tank of the fluid storage system according to 1 ;
• 3 A schematic flow diagram of a method according to the invention;
• 4 A graphical pressure curve of the actual pressure of the fluid depending on the functional position of the valve means of the valve units.

1 shows a fluid storage system provided overall with the reference number 2. The fluid storage system 2 includes in the in 1 shown embodiment three fluid tanks 4, in which a fluid can be stored or stored under pressure. The fluid can be, for example, hydrogen.

In addition, the fluid storage system 2 includes three valve units 6, each of which has a valve unit 6 arranged on a fluid tank 4. The valve units 6 each include a supply path 10 along which fluid can flow from the fluid tank 4 through the valve unit 6 in the direction of a consumer 12. The consumer 12 can be, for example, a fuel cell.

In addition, the valve units 6 each include a refueling path 14 through which fluid for filling the fluid tank 4 can flow through the valve unit 6 into the fluid tank 4. At least one controllable valve means 16 is arranged in the supply path 10, which can be moved from a closed functional position, in which flow through the valve means 16 is blocked, to an open functional position, in which fluid can flow through the valve means 16.

In addition, the fluid storage system 2 includes a control unit 18, through which the valve means 16 of the valve unit 6 can be controlled for opening and closing.

In the exemplary embodiment shown in the figures, the valve means 16 each include solenoid valves, which are automatically transferred from the closed functional position to the open functional position by electrical current and back to the closed functional position in a de-energized state.

The three valve units 6 open into the in 1 shown embodiment together in a distribution unit 20, which includes a distribution section 22. In the distribution section 22 of the distributor lerunit 20, a sensor means 24 is arranged, through which an actual pressure of the fluid on the side of the distribution units 20 facing the consumer 12 can be detected. The fluid tanks 4 can also be filled with fluid via the distribution unit 20. In such a case, fluid is supplied to the distribution unit 20 via an inlet 26 and supplied to the respective fluid tanks 4 via the refueling path 14 via the valve units 6. In addition, the exemplary embodiment of the fluid storage system 2 according to 1 a pressure control element 28, which is functionally assigned to the control unit 18 and through which the actual pressure of the fluid on the downstream side of the valve means 16 or the valve units 6 can be increased or lowered in the open functional position of the valve means 16.

• In einem ersten Schritt 100 werden die Fluidtanks 4 mit Fluid befüllt. Das Beenden des Befüllens der Fluidtanks 4, insbesondere das Beenden des Betankungsvorgangs, wird im Schritt 100 festgestellt.

3 shows a schematic flow diagram of an embodiment of the method according to the invention. With reference to the representation of the 1 and 2 The procedure is described below:

• In a first step 100, the fluid tanks 4 are filled with fluid. The completion of the filling of the fluid tanks 4, in particular the completion of the refueling process, is determined in step 100.

After detecting the completion of the refueling process of the fluid tanks 4, a valve means de-icing procedure 100 is carried out. In a first step 101, a valve means 16 of a first valve unit 6 is transferred from the closed functional position to the open functional position. In step 101a, the valve means 16 can remain in the open functional position for a maximum of 2 seconds, in particular a maximum of 5 seconds, in particular a maximum of 10 seconds, before it is returned to the closed functional position. Back in the closed functional position, the control unit 18 detects a pressure drop in the actual pressure of the fluid on the downstream side of the valve unit 6 since the valve means 16 was transferred into the closed functional position by the sensor means 24. If the pressure drop reaches or exceeds a value stored in the control unit 18, the valve means 16 is returned to the open functional position. The value stored in the control unit 18 includes, for example, 30 bar.

After the valve means 16 of the first valve unit 6 has been opened and closed again three times, the in 4 In the exemplary embodiment shown, the valve defrosting procedure is completed. Thereafter, in a step 101b, analogous to step 101a, a valve means 16 of a second valve unit 6 is subjected to the valve means de-icing procedure.

When the valve means de-icing procedure is completed in step 101b for the valve means 16 of the second valve unit 6, in a step 101c a valve means 16 of a third valve unit 6 is subjected to the valve means de-icing procedure. When changing from steps 101a to 101b and from 101b to 101c, a transition time period can be provided, for example 2 seconds, for example 5 seconds, for example at least 10 seconds.

After steps 101a, 101b and 101c have been completed, in 4 shown embodiment of the method can be returned to normal operation.

4 shows a course of the actual pressure 30 of the fluid when going through method steps 101a to 101c according to the method 3 .

Time runs from left to right. At the beginning, all valve means 16 of the valve units 6 are open. Then all three valves are closed first and the first pressure drop occurs as the fuel cell consumes H2. Thereafter, only one valve means 16 of a valve unit 6 is always in an open or closed functional position. When the valve means 16 is transferred from the open functional position to the closed functional position, it can be seen that the actual pressure 30 suffers a pressure drop. When it is transferred again from the closed functional position to the open functional position, the initial pressure is at least almost reached again.

The features of the invention disclosed in the above description, in the claims and in the drawing may be essential both individually and in any combination in the implementation of the invention in its various embodiments within the scope of the following claims.

Reference symbol list

2

Fluid storage system

4

Fluid tank

6

Valve unit

10

supply path

12

consumer

14

Refueling path

16

Valve means

18

Control unit

20

Distribution unit

22

distribution section

24

Sensor means

26

inlet

28

Pressure control element

30

ACTUAL pressure

100-101c

Procedural steps

Claims (10)

Method for operating a fluid storage system (2), which has at least one fluid tank (4) in which a fluid can be stored or stored under pressure, which has at least one valve unit (6) which is arranged on the fluid tank (4) and which has a supply path (10 ), along which fluid can flow from the fluid tank (4) through the valve unit (6) in the direction of a consumer (12), as well as a refueling path (14) through which fluid for filling the fluid tank (4) through the valve unit (6 ) can flow into the fluid tank (4), with at least one controllable valve means (16) being arranged in the supply path (10), which can be moved from a closed functional position, in which flow through the valve means (16) is blocked, into an open functional position , in which fluid can flow through the valve means (16), and which comprises at least one control unit (18), through which the valve means (16) of the valve unit (6) can be controlled for opening and closing and through which at least when detecting the termination of a During the refueling process of the fluid tank (4), a valve means de-icing procedure is carried out, in which the valve means (16) of the valve unit (6) is transferred from the closed functional position to the open functional position and back again to the closed functional position. Procedure according to Claim 1 , characterized in that at least one sensor means (24) is functionally assigned to the control unit (18), through which an actual pressure (30) of the fluid on the downstream side of the valve unit (6) can be detected, wherein the control unit (18) a pressure drop in the actual pressure (30) of the fluid on the downstream side of the valve unit (6) since the valve means (16) was transferred to the closed functional position is detected and the valve means (16) is transferred from the closed functional position to the open functional position when the pressure drop detected by the control unit (18) reaches or exceeds a value stored in the control unit (18). Procedure according to one of the Claims 1 or 2 , characterized in that when carrying out the valve means de-icing procedure, the valve means (16) of the valve unit (6) is transferred at least twice, in particular at least three times, from the closed functional position to the open functional position and back again to the closed functional position. Method according to one of the preceding claims, characterized in that in the valve means de-icing procedure the valve means (16) after being transferred from the closed functional position to the open functional position after an open period has elapsed, in particular after a maximum of 2 seconds, in particular after a maximum 5 seconds, in particular after a maximum of 10 seconds, is returned to the closed functional position. Method according to one of the preceding claims, characterized in that in the control unit (18) a TARGET pressure range on the downstream side of the valve unit (6) with the functional position of the valve means (16) closed after a period of time after completion of the valve means de-icing process. Procedure is stored, wherein a pressure drop in the actual pressure (30) of the fluid on the downstream side of the valve unit (6) is detected by the control unit (18) and the valve medium de-icing procedure is carried out again by the control unit (18). is initiated when the ACTUAL pressure (30) detected by the control unit (18) is above the TARGET pressure range after the period of time has elapsed. Method according to one of the preceding claims, characterized in that the at least one valve means (16) comprises a solenoid valve which can be converted into the open functional position by the control unit (18) by electrically energizing the closed functional position and again by the control unit (18). can be transferred back to the closed functional position or is automatically transferred to the closed functional position in the de-energized state. Method according to one of the preceding claims, characterized in that the valve means de-icing procedure comprises increasing and/or decreasing the mass flow of the fluid flowing through the valve means (16) of the valve unit (6). Procedure according to Claim 7 , characterized in that the increasing and/or lowering of the pressure and/or the mass flow rate of the fluid flowing through the at least one valve means (16) occurs once or occurs at least twice. Method according to one of the preceding claims, characterized in that the fluid storage system (2) comprises at least two, in particular at least three, valve units (6), which are each arranged on a separate fluid tank (4) or on a common fluid tank (4), and that the fluid storage system (2) comprises at least one distribution unit (20) into which the at least two valve units (6), in particular at least three valve units (6), in a distributor section (22) of the distributor unit (20), through which the flowing fluid can be passed on to a consumer (12) and in which the sensor means (24) is arranged in the distributor section (22), the through which Sensor means (24) detects the actual pressure (30) of the fluid in the distributor section (22) of the distributor unit (20). Procedure according to Claim 9 , characterized in that the valve means de-icing procedure involves a joint and simultaneous or a separate and successive transfer from the closed functional position to the open functional position and back again to the closed functional position of the valve means (16) of the at least two valve units (6), in particular the valve means (16) of the at least three valve units (6), wherein after a valve means (16) of a valve unit (6) has been transferred from the open functional position to the closed functional position, a valve means (16) of a further valve unit (6) of the open functional position is transferred to the closed functional position, or that the valve means de-icing procedure involves a separate and successive passage through the valve means de-icing procedure of the valve means (16) of the at least two valve units (6), in particular the valve means (16). at least three valve units (6), wherein after completion of the valve means de-icing procedure of a valve unit (6), the valve means de-icing procedure of a further valve unit (6) is started.

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