WO2024099695A1

WO2024099695A1 - Gas tank system and method for monitoring filling of a gas tank system

Info

Publication number: WO2024099695A1
Application number: PCT/EP2023/078656
Authority: WO
Inventors: Christian Kuhnert; Birgit LENZ; Stefan Kieferle; Markus Strasser; Nicolas WUSSLER; Martin Schwab; Christian Schugger
Original assignee: Robert Bosch Gmbh
Priority date: 2022-11-07
Filing date: 2023-10-16
Publication date: 2024-05-16
Also published as: DE102022211721A1

Abstract

The invention relates to methods for monitoring the filling of a gas tank system, by way of which the occurrence of inadmissible pressure losses across valve devices that connect a high-pressure line system to a respective tank can be determined. The invention also relates to a gas tank system.

Description

Description of a filling of a

Technical area

The present invention relates to a gas tank system and various methods for monitoring a filling of gas tank systems with one or more tanks.

State of the art

Fuel cells are increasingly being used as energy converters, including in vehicles, to convert chemical energy stored in a fuel such as hydrogen together with oxygen directly into electrical energy. Fuel cells have an anode, a cathode and an electrolytic membrane arranged between the anode and cathode. The fuel is oxidized at the anode and the oxygen is reduced at the cathode.

The fuel is usually supplied to the fuel cell via a pipe system from a tank in which the gaseous fuel is stored at high pressure. A separating or shut-off valve is usually provided between the tank and a high-pressure part of the pipe system. The high-pressure part is also typically connected to a pipe part connected to the fuel cell via a flow control valve.

US 10 030 816 B2 discloses a method and a system for filling a gas tank system. Disclosure of the invention

The present invention provides a method for monitoring the filling of a gas tank system with the features of claim 1, a method for monitoring the filling of a gas tank system with the features of claim 2, a method for monitoring the filling of a gas tank system with the features of claim 5, a method for monitoring the filling of a gas tank system with the features of claim 6 and a method for monitoring the filling of a gas tank system with the features of claim 7 as well as a gas tank system with the features of claim 10.

Advantageous embodiments and further developments emerge from the further subclaims and from the description with reference to the figures of the drawing.

One idea underlying the invention is to detect an inadmissibly high pressure loss during the filling of a tank in a valve device that connects a high-pressure line system to the tank. Such inadmissible pressure losses in the valve device lead to underfilling of the tank. In particular in systems with several tanks, this can result in undesirable pressure equalization processes after the end of the filling. According to the invention, the pressure loss is detected, in particular by recording the pressure in the high-pressure line system during filling and additionally evaluating a thermodynamic state variable in the tank or tanks during filling, by recording the pressure in the high-pressure line system and additionally evaluating a thermodynamic state variable in the tank or tanks before and after filling, by evaluating a temperature development in the several tanks after filling with subsequent removal of gas from the tanks or by evaluating the pressure curve in the high-pressure line system after filling with subsequent removal of gas from the tanks. If an inadmissibly high pressure loss is detected based on the recorded or determined values, e.g. by comparison with corresponding threshold values, an error signal is generated by means of an electronic control device. This can include, for example, writing an entry in a data memory and/or issuing a warning signal.

One advantage of the invention is that the presence of valve devices whose permeability is reduced and which therefore make it difficult to completely fill the respective tank can be detected quickly and effectively. According to some embodiments, the respective valve devices can advantageously be localized.

The invention is explained below with reference to the figures of the drawings. The figures show:

Fig. 1 is a schematic representation of a hydraulic circuit diagram of a fuel cell system with a gas tank system according to an embodiment of the invention;

Fig. 2 is a flow chart of a method according to an embodiment of the invention;

Fig. 3 is a flow chart of a method according to another embodiment of the invention

Fig. 4 is a flow chart of a method according to another embodiment of the invention;

Fig. 5 is a flow chart of a method according to another embodiment of the invention;

Fig. 6 is a flow chart of a method according to another embodiment of the invention. In the figures, the same reference symbols designate identical or functionally identical components, unless otherwise stated.

Fig. 1 shows a schematic of a fuel cell system 200 that can be used in a vehicle, for example. The fuel cell system 200 comprises a gas tank system 100 and a consumer system 205.

As shown only schematically in Fig. 1, the consumer system 205 has a fuel cell arrangement 210. The fuel cell arrangement 210 has at least one fuel cell, but preferably several fuel cells connected electrically in series, which are designed to convert chemical energy stored in a gaseous fuel, such as hydrogen, together with oxygen directly into electrical energy. As further shown schematically in Fig. 1, the fuel cell arrangement 210 has a fuel supply connection 211, via which gaseous fuel can be supplied to the fuel cell arrangement 210, in particular to an anode of the at least one fuel cell.

The gas tank system 100 is explained below in connection with the fuel cell system 200, but is not limited to this use. As shown schematically in Fig. 1, the gas tank system 100 has a plurality of tanks 1, a high-pressure line system 2, a number of first valve devices 3 corresponding to the number of tanks 1, an optional flow control device 5, a first pressure sensor 4 and a control device 6. The gas tank system 100 also has a refueling connection or supply connection 20. As is also shown in Fig. 1 purely by way of example, each tank 1 can be equipped with a second pressure sensor 7 and/or with a temperature sensor 9.

In Fig. 1, a gas tank system 100 with three tanks 1A, 1B, 1C is shown purely as an example. However, the invention is not limited to this. In general, at least two tanks 1 can be provided, although more than three tanks 1 can also be provided. Each tank 1 is designed to store gas, in particular hydrogen. For example, each tank 1 can be designed to store gas at a pressure of up to 800 bar. The high-pressure line system 2 can in particular have a connecting line 21, a plenum 24 connected to the connecting line 21 and a number of connecting lines 23 corresponding to the number of tanks 1, each of which connects the plenum 24 to the respective tank 1. As shown in Fig. 1 purely by way of example, the first tank 1A can thus be connected to the plenum 24 via a first connecting line 23A, the second tank 1B via a second connecting line 23B and the third tank 1C via a third connecting line 23C. The connecting line 21 connects the plenum 24 to the consumer system 205. Optionally, a supply line 22 can also be provided, which is connected to the plenum 24 and the optional supply device 20.

The first valve devices 3 can each have a switchable solenoid valve 3 that can be switched between a closed state and an open state. In general, each first valve device 3 can be switched between a closed state and an open state. Optionally, each first valve device 3 can also have a filter 30, as shown schematically in Fig. 1. As shown schematically in Fig. 1, each valve device 3 is arranged between the tank 1 and the high-pressure line system 2. For example, each first valve device 3 can be arranged in a respective connecting line 23, as shown by way of example in Fig. 1. In the open state, the respective first valve device 3 connects the respective tank 1 to the high-pressure line system 2. In the closed state, the respective first valve device 3 separates the tank 1 and the high-pressure line system 2 from one another.

The optional flow control device 5 can also be switched between a closed state and an open state. The flow control device 5 can also be referred to as a pressure regulator and is generally designed to vary a gas flow or a pressure of the flowing gas. In particular, the flow control device 5 can have a second valve device, e.g. in the form of a solenoid valve, which can be switched between the closed state and the open state. As shown schematically in Fig. 1, the flow control device is arranged between the consumer system 205 and the high-pressure line system 2, in particular between the consumer system 205 and the connecting line 21. In the open state, the flow control device 5 connects the consumer system 205 to the high-pressure line system 2. In the closed state, the flow control device 5 separates the consumer system 205 and the high-pressure line system 2 from one another.

The tanks 1 are thus connected in parallel to one another to the high-pressure line system 2 or are connected to it. When the first valve device 3 and the second valve device 5 are open, the tanks 1 jointly supply a gas mass flow to the consumer system 205.

The supply line 22 is connected to the supply connection 20, which can be designed, for example, as a plug connection for a tank nozzle. As shown in Fig. 1, a check valve 8 can be arranged in the supply line 22, which closes the supply connection 20 against gas escaping from the high-pressure line system 2. Gas from a supply source, e.g. a gas station, can be supplied to the tanks 1 via the supply connection 20 through the high-pressure line system 2 when the first valve devices 3 are open in a filling process.

As shown in Fig. 1, the first pressure sensor 4 is connected to the high-pressure line system 2 and is configured to detect a pressure in the high-pressure line system 2. As shown in Fig. 1, the pressure sensor 4 can, for example, detect a pressure in the plenum 24.

The second pressure sensors 7 are assigned to the tanks 1, with each second pressure sensor 7 being designed to detect a pressure in a respective tank 1. In the same way, alternatively or in addition to the second pressure sensors 7, the temperature sensors 9 can be assigned to the tanks 1, with each temperature sensor 9 being designed to detect a pressure in a respective tank 1. The temperature sensors 9 are not necessarily arranged in the interior of the tank 1, as shown purely by way of example in Fig. 1, but can also be arranged on the outside of the tank 1, in which case Case a temperature in tank 1 is approximately determined based on the values recorded by temperature sensor 9.

The control device 6 is shown only schematically as a block in Fig. 1 and is implemented as an electronic control device 6. As shown by way of example in Fig. 1, the control device 6 can have a computing unit 61, such as a CPU, an ASIC, an FPGA or the like, and a data memory 62, in particular a non-volatile data memory such as a flash memory, an SD memory or the like, which can be read by the computing unit 61. As shown schematically in Fig. 1, the control device 6 is connected to the first valve device 3, optionally to the flow control device 5 and to the pressure sensor 4 in a signal-conducting manner, for example by wire, such as via a bus system. Alternatively, a wireless connection can also be provided, e.g. via WiFi or the like.

The control device 6 is designed to cause the gas tank system 100 to carry out one of the methods U, V, W, X, Y shown in Figs. 2 to 6 for monitoring the filling of the gas tank system 100. For example, software can be stored in the data memory 62 that can be executed by the computing unit 61 in order to cause the system 100 to carry out the respective method U, V, W, X, Y.

As already explained above, gas from a supply source, e.g. a gas station, can be supplied to the tanks 1 via the supply connection 20 through the high-pressure line system 2 when the first valve devices 3 are open during a filling process. It is desirable that all tanks 1 store essentially the same mass of gas at the end of the filling process. When gas is supplied to the tanks 1, pressure losses naturally occur at the first valve devices 3. If the pressure loss at one of the valve devices 3 becomes large, in particular significantly larger than at the other valve devices 3, this can lead to a desired filling quantity not being reached in the respective tank. Unacceptably high pressure losses can occur, for example, if the permeability of the filter 30 of the respective first valve device 3 is reduced. With the following explained Using methods U, V, W, X, Y it is possible to detect the presence of an inadmissibly high pressure loss at at least one of the first valve devices 3.

Fig. 2 shows a sequence of a method U for monitoring the filling of a gas tank system 100. The method U can be carried out on the gas tank system 100 shown in Fig. 1 and is explained below with reference to Fig. 1. Alternatively, the method U can also be carried out in a system with only one tank 1.

In step U1, gas is supplied to the tanks 1 via the high-pressure line system 2. The first valve devices 3 are in the open state.

In step U2, a first pressure in the high-pressure line system 2 is recorded over a predetermined recording period during the supply (step M1) of gas into the tank 1. For example, the first pressure can be continuously recorded by the first pressure sensor 4 and transmitted to the control device 6. The control device 6 can thus record a temporal pressure curve of the pressure in the high-pressure line system 2. The recording period can, for example, extend from the start of the gas supply in step M1 to a point in time at which the gas supply to the high-pressure line system 2 is terminated. Alternatively, the recording period can comprise a discrete period of time, e.g. of more than 10 seconds, which lies between the time of the start and the end of the gas supply to the high-pressure line system 2.

In step U3, a pressure gradient in the high-pressure line system is determined from the detected pressure, e.g. by means of the control device 6. For example, a pressure gradient can be formed for certain time periods, e.g. for time periods of 5 seconds each, of the detection period.

After step U3, method U may alternatively or cumulatively execute steps U41, U51, U61 or steps U42, U52, U62. In step U41, a second pressure in the tank 1 or the tanks 1 is recorded during the recording period, in particular continuously. This can be done, for example, by means of the second pressure sensors 7, which transmit the recorded pressure values to the control device 6. The control device 6 can thus record a pressure curve in the tank 1 over the recording period.

In the same way, alternatively or additionally, in step U42, a temperature in the tank 1 or the tanks 1 can be recorded during the recording period and transmitted to the control device 6, in particular continuously. The control device 6 can thus record a temperature profile in the tank 1 over the recording period.

In step U51, a pressure difference between the first and second pressures is determined. For example, the control device 6 can form a difference between the first and second pressures for all values of the first and second pressures detected during the detection period. In step U52, a temperature change during the detection period is determined. For example, the control device 6 can form a difference between the temperature at the end of the detection period and the temperature at the beginning of the detection period.

In step U61, the determined pressure difference is compared with a pressure threshold value that depends on the first pressure and the pressure gradient. The determined pressure difference is representative of a pressure loss at the respective first valve device 3. However, the pressure losses vary depending on the flow speed and density of the gas. This is taken into account by the dependency of the pressure threshold value, which represents a maximum permissible pressure loss. For example, a functional relationship can be stored in the data memory 62 that describes the dependency of the pressure threshold value on the first pressure and the pressure gradient and with the help of which the computing unit 61 can calculate the respective pressure threshold value. Alternatively, a look-up table can also be stored in the data memory 62 in which a specific pressure threshold value is assigned to a value of the pressure gradient and a value of the first pressure. The Comparison step U62 can be carried out, for example, for each time period for which a pressure gradient is determined.

If the determined pressure difference exceeds the pressure threshold, as indicated in Fig. 2 by the symbol "+", there is an impermissibly high pressure loss at the respective valve device 3 and the method U proceeds to step M7. If this is not the case, as shown in Fig. 2 by the symbol, the method U can be terminated, for example (block E).

In step U62, however, the determined temperature change is compared with a temperature change threshold value that is dependent on the first pressure and the pressure gradient, e.g. by the control device 6. The temperature change also represents the pressure losses occurring at the respective valve device 3, with the temperature change being smaller the greater the pressure loss. As explained above, the pressure loss is also dependent on the flow velocity and the density of the gas. The temperature change threshold value can therefore vary depending on the first pressure and the pressure gradient. For example, a functional relationship can be stored in the data memory 62 that describes the dependence of the temperature threshold value on the first pressure and the pressure gradient and with the aid of which the computing unit 61 can calculate the respective temperature threshold value. Alternatively, a look-up table can also be stored in the data memory 62 in which a specific temperature threshold value is assigned to a value of the pressure gradient and a value of the first pressure.

The step U62 can be carried out individually for each tank 1. In this case, the temperature change determined for the respective tank 1 can be compared with a temperature change threshold value that is individual for this tank 1 or with a threshold value that is valid for all tanks 1. Alternatively, it is also conceivable that a maximum permissible difference in the temperature changes in the individual tanks 1 is used as the temperature change threshold value, and the comparison U62 of the determined temperature change with the temperature change threshold value involves determining a difference in the temperature changes of the individual tanks 1 and comparing it with the maximum permissible difference. This means that it is checked whether the individual tanks 1 heat up to different degrees. If one of the tanks 1 heats up significantly less than the others, in particular than the tank 1 that heats up the most, it can be concluded that there is an impermissible pressure loss at the first valve device 3. For this purpose, the control device 6 can compare the individual temperature changes of the tanks 1 with one another and calculate a difference between the largest and the smallest of the determined temperature changes and compare this difference with a threshold value in the form of a maximum permissible difference. This makes it easy to determine, in particular with an algorithm that requires little computing power, the tank 1 and the associated valve device 3 at which the greatest pressure loss occurs.

Analogous to step U61, the method U proceeds in step U62 to step U7 if the determined temperature change falls below the temperature change threshold, as shown in Fig. 2 by the symbol “+”, or, if this is not the case, to block E, as shown in Fig. 2 by the symbol

is marked.

In step U7, i.e. in the event that the determined pressure difference exceeds the pressure threshold or the determined temperature change falls below the temperature change threshold, the control device 6 generates an error signal. For example, this can include writing an error entry into the data memory 62 by the computing unit 61. Alternatively or additionally, the control device 6, in particular the computing device, can output a warning signal, e.g. in the form of an acoustic or optical warning signal. In steps U61, U62, in the case of multiple tanks 1, the temperature changes or pressure differences determined individually for each tank 1 and the associated first valve device 3 are compared with threshold values. Optionally, generating the error signal in step U7 can also include writing information identifying the tank 1 and the associated first valve device 3 together with the error entry into the data memory 62. For example, the error entry can contain an index that identifies the tank 1 and the associated first valve device 3. The method U shown schematically in Fig. 2 enables simple and efficient detection of inadmissibly high pressure losses at the first valve devices 3 when filling the tanks 1.

Fig. 3 shows an example of a further method V for monitoring the filling of a gas tank system 100, which is described below by way of example with reference to the system 100 explained in Fig. 1. Alternatively, the method U can also be carried out in a system with only one tank 1.

In step V1, a first pressure is detected in the high-pressure line system 2. For example, the first pressure can be continuously detected by the first pressure sensor 4 and transmitted to the control device 6. The control device 6 can thus record a temporal pressure curve of the pressure in the high-pressure line system 2.

In step V2, a first temperature in the tank 1 or in each tank 1 is recorded, in particular by means of the temperature sensors 9, e.g. continuously. The recorded temperature can be transmitted to the control device 6. The control device 6 can thus record a temperature profile in the tank 1.

In step V3, gas is supplied to the tank 1 or the tanks 1 via the high-pressure line system 2, i.e. in a state in which the first valve devices 3 are open. In this case, gas is supplied to the high-pressure line system 2 at the supply device 20 from a supply source and the high-pressure line system 2 passes the gas on to the tanks 1. The flow control device 5 is preferably closed. The first temperature and the first pressure can be detected in particular before the start of the gas supply in the high-pressure line system 2, in particular in a state in which the first valve devices 3 are open and the flow control device 5 is closed. A pressure that is stationary in this state can be detected as the first pressure, and the temperature that is stationary as the first temperature. In step V4, the gas supply to the high-pressure line system 2 is stopped. For example, the control device 6 can output a control signal to an interface (not shown) which communicates with a control of the supply source in order to stop the gas supply. For example, the gas supply can be stopped when a predetermined pressure is reached in the high-pressure line system 2.

In step V5, after stopping the gas supply in step V4, a second pressure in the high-pressure line system 2 is detected, e.g. by means of the first pressure sensor 4.

In step V6, a second temperature is recorded in the tank 1 after the gas supply has been stopped 1 (step V4). In this case, the first valve devices 3 can be opened and the flow control device 5 can be closed. The pressure that is stationary in this state can be recorded as the second pressure, and the temperature that is stationary as the second temperature.

In step V7, a pressure change in the high-pressure line system 2 is determined from the first and second pressures and a temperature change in the tank 1 or in each is determined from the first and second temperatures. For example, the control device 6 can form a pressure difference for the high-pressure line system 2 and an individual temperature difference for each tank 1, which corresponds to the respective temperature change.

In step V8, a comparison is made, e.g. by means of the control device 6, of the determined temperature change with a temperature change threshold value dependent on the determined pressure change. The temperature change threshold value can additionally depend on one or more of the following boundary conditions: the first pressure, the first temperature, the ambient temperature. The latter can be detected e.g. by means of a further temperature sensor (not shown) and transmitted to the control device 6. In the data memory 62, for example, a functional relationship can be stored which determines the Dependence of the temperature change threshold value on the pressure change and, if applicable, on the other boundary conditions and with the aid of which the computing unit 61 can calculate the respective temperature change threshold value. Alternatively, a look-up table can be stored in the data memory 62 in which a specific temperature change threshold value is assigned to the values of the boundary conditions.

If the comparison in step V8 shows that the determined temperature change falls below the temperature change threshold value, as shown in Fig. 3 by the symbol "+", the method proceeds to step V9. Otherwise, as shown in Fig. 3 by the symbol , the method V can be terminated, for example (block E).

Step V8 can be carried out individually for each tank 1. The temperature change determined for the respective tank 1 can be compared with a temperature change threshold value that is individual for this tank 1 or with a threshold value that is valid for all tanks 1. Alternatively, it is also conceivable that a maximum permissible difference in the temperature changes in the individual tanks 1 is used as the temperature change threshold value, and the comparison V8 of the determined temperature change with the temperature change threshold value comprises determining a difference in the temperature changes of the individual tanks 1 and comparing it with the maximum permissible difference. This means that it is checked whether the individual tanks 1 heat up to different degrees. If one of the tanks 1 heats up significantly less than the others, in particular than the tank 1 that heats up the most, it can be concluded that the tank is insufficiently filled due to an impermissible pressure loss at the first valve device 3. For this purpose, the control device 6 can compare the individual temperature changes of the tanks 1 with one another and form a difference between the largest and the smallest of the determined temperature changes and compare this difference with a threshold value in the form of a maximum permissible difference. This makes it easy to determine, in particular with an algorithm that requires little computing power, the tank 1 and the associated valve device 3 at which the greatest pressure loss occurs. In step V9, the control device 6 generates an error signal. For example, this can include writing an error entry into the data memory 62 by the computing unit 61. Alternatively or additionally, the control device 6, in particular the computing device, can output a warning signal, e.g. in the form of an acoustic or optical warning signal. In step V8, in the case of several tanks 1, the temperature changes determined individually for each tank 1 and the associated first valve device 3 are compared with threshold values. Optionally, the generation of the error signal in step V9 can also include writing an error entry into the tank

1 and the associated first valve device 3 together with the error entry in the data memory 62. For example, the error entry can contain an index that identifies the tank 1 and the associated first valve device 3.

The method V shown schematically in Fig. 3 enables simple and efficient detection of inadmissibly high pressure losses at the first valve devices 3 when filling the tanks 1. In contrast to the method shown in Fig.

2, the pressure in the high-pressure line system 2 and the temperature in the tank 1 do not necessarily have to be monitored continuously during filling. For monitoring the valve devices 3, it is sufficient in method V that the pressure and temperature are recorded before the start and after the end of filling. This further simplifies data processing and can be carried out with even less computing effort.

Fig. 4 shows an example of a further method W for monitoring a filling of a gas tank system 100, which is described below by way of example with reference to the system 100 explained in Fig. 1.

In step W1, gas is supplied to the tanks 1 via the high-pressure line system 2 with the first valve devices 3 open. In this case, gas is supplied to the high-pressure line system 2 at the supply device 20 from a supply source and the high-pressure line system 2 passes the gas on to the tanks 1. The flow control device 5 is preferably closed in this case. In step W2, the gas supply to the high-pressure line system 2 is stopped. For example, the control device 6 can output a control signal to an interface (not shown) which communicates with a control of the supply source in order to stop the gas supply. For example, the gas supply can be stopped when a predetermined pressure is reached in the high-pressure line system 2, which is optionally detected in step W3, which is explained below, by means of the first pressure sensor 4 and transmitted to the control device 6.

In step W3, a pressure in the high-pressure line system 2 is detected. The pressure can be detected, for example, by means of the first pressure sensor 4 and transmitted to the control device 6. Step W3 can optionally be carried out during the gas supply (step W1) and is carried out after the gas supply is stopped in step W2 for at least a predetermined period of time, e.g. a period in a range between 2 and 20 seconds. The detection of the pressure and the transmission to the control device 6 can in particular take place continuously.

In step W4, a pressure gradient in the high-pressure line system 2 is determined from the recorded pressure at least for the predetermined period of time after stopping (step W2) the gas supply, e.g. by means of the control device 6. After stopping the gas supply, the first valve devices 3 remain open for the predetermined period of time. This allows pressure equalization between the tanks 1 to take place if they are unevenly filled. This equalization process results in a negative pressure gradient. The uneven filling is a sign that a high pressure loss is occurring at one of the first valve devices 3.

In step W5, the pressure gradient determined for the period after stopping (step W2) the gas supply is compared with a threshold value. For example, the control device 6 can first check the sign of the pressure gradient and further compare the amount of the pressure gradient with a threshold value for the pressure gradient if the pressure gradient has a negative sign. If the determined pressure gradient is negative and an amount of the determined pressure gradient exceeds the threshold value, the method proceeds to step W6, as shown in Fig. 4 by the symbol "+". Otherwise, the method W can be terminated, for example (block E), as shown in Fig. 4 by the symbol .

In step W6, the control device 6 generates an error signal. For example, this can include writing an error entry into the data memory 62 by the computing unit 61. Alternatively or additionally, the control device 6, in particular the computing device, can output a warning signal, e.g. in the form of an acoustic or optical warning signal.

The method W shown schematically in Fig. 4 enables a simple and efficient detection of inadmissibly high pressure losses at the first valve devices 3 when filling the tanks 1.

Fig. 5 shows a further method X for monitoring a filling of a gas tank system 100, which is explained below by way of example with reference to the gas tank system 100 shown in Fig. 1.

In step X1, gas is supplied to the tanks 1 via the high-pressure line system 2. In this case, the first valve devices 3 are opened and the flow control device 5 is preferably closed. Gas is supplied to the high-pressure line system 2 from a supply source at the supply device 20 and the high-pressure line system 2 passes the gas on to the tanks 1.

In step X2, the gas supply to the high-pressure line system 2 is stopped. For example, the control device 6 can output a control signal to an interface (not shown) which communicates with a control of the supply source in order to stop the gas supply. For example, the gas supply can be stopped when a predetermined pressure is reached in the high-pressure line system 2, which is optionally detected during the execution of step X1 by means of the first pressure sensor 4 and transmitted to the control device 6. In step X3, the first valve devices 3 are closed so that the tanks 1 are separated from the high-pressure line system 2. For example, the control device 6 can output a control signal to the first valve devices 3 in order to switch them from the open to the closed state.

Subsequently, in step X4, the first valve devices 3 are opened again, e.g. by a control signal output by the control device 6, so that the tanks 1 are again connected to the high-pressure line system 2. Optionally, the flow control device 5 can also be opened so that gas from the tanks 1 is supplied to the consumer system 205 through the high-pressure line system 2.

After opening the first valve devices 3 in step X4, a temperature in each tank 1 is detected in step X5, at least over a predetermined detection period after opening X4 of the first valve devices 3. This can be done, for example, continuously by means of the temperature sensors 9, which transmit the detected temperatures to the control device 6.

In step X6, a temperature change in the tanks 1 over the predetermined detection period is determined or ascertained from the detected temperatures, e.g. using the control device 6. For example, this can initially comprise a pure determination of whether a temperature increase or a temperature drop is taking place in the respective tank 1. If the temperature change corresponds to a temperature increase, the amount of the temperature change can also be ascertained.

In step X7, the determined temperature changes are compared with a temperature change threshold value, for example by the control device. In this case, the temperature change determined for the respective tank 1 can be compared with a temperature change threshold value that is individual for this tank 1 or with a threshold value that is valid for all tanks 1. If it is determined in step X7 that the temperature change in at least one tank 1 corresponds to a temperature increase and the temperature change determined for this tank 1 exceeds the If the temperature change threshold value exceeds the value of the temperature change threshold value, the method X proceeds to step X8, as indicated in Fig. 5 by the symbol "+". Otherwise, as shown in Fig. 5 by the symbol , the method X can be terminated (block E). A temperature increase in a tank 1 after the first valve devices 3 have been reopened can occur as a result of this tank 1 being refilled from the other tanks 1. Consequently, this tank 1 was not filled to the same extent as the other tanks 1, which indicates a reduced flow or increased pressure loss in the associated first valve device 3.

In step X8, the control device 6 generates an error signal. For example, this can include writing an error entry into the data memory 62 by the computing unit 61. Alternatively or additionally, the control device 6, in particular the computing device, can output a warning signal, e.g. in the form of an acoustic or optical warning signal. In step X7, the temperature changes determined individually for each tank 1 and the associated first valve device 3 are compared with the threshold value. Optionally, generating the error signal in step X8 can also include writing information identifying the tank 1 and the associated first valve device 3 together with the error entry into the data memory 62. For example, the error entry can contain an index that identifies the tank 1 and the associated first valve device 3.

The method X shown schematically in Fig. 5 enables simple and efficient detection of impermissibly high pressure losses at the first valve devices 3 when filling the tanks 1. With the method X, the pressure in the high-pressure line system 2 and the temperature in the tank 1 do not necessarily have to be monitored during filling in order to determine a pressure loss at a first valve device 3. For monitoring the valve devices 3, with the method X it is sufficient that after filling or during subsequent removal of gas from the tanks 1 the temperature development in the tanks 1 is monitored immediately after the opening of the first valve devices 3. Fig. 6 shows a further method Y for monitoring a filling of a gas tank system 100, which is explained below by way of example with reference to the gas tank system 100 shown in Fig. 1.

In step Y1, gas is supplied to the tanks 1 via the high-pressure line system 2. In this case, the first valve devices 3 are opened and the flow control device 5 is preferably closed. Gas is supplied to the high-pressure line system 2 from a supply source at the supply device 20 and the high-pressure line system 2 passes the gas on to the tanks 1.

In the optional step Y2, a filling pressure in the high-pressure line system 2 is detected during the supply Y1 of gas 1 into the tanks 1, e.g. by means of the first pressure sensor 4, and transmitted to the control device 6.

In step Y3, the gas supply to the high-pressure line system 2 is stopped. For example, the control device 6 can output a control signal to an interface (not shown) which communicates with a controller of the supply source in order to stop the gas supply. For example, the gas supply can be stopped when in the high-pressure line system 2, when the detected filling pressure reaches a reference value.

Furthermore, the valve devices 3 are closed (step Y4) so that the tanks 1 are separated from the high-pressure line system 2. For example, the control device 6 can output a control signal to the first valve devices 3 in order to switch them from the open to the closed state.

Subsequently, in step Y5, the first valve devices 3 are opened again, e.g. by a control signal output by the control device 6, so that the tanks 1 are again connected to the high-pressure line system 2.

In step Y6, a predetermined mass flow of gas is taken from the tanks 1 via the high-pressure line system 2. For example, the Flow control device 5 is opened so that gas from the tanks 1 is supplied to the consumer system 205 through the high-pressure line system 2. For this purpose, the control device 6 outputs a control signal to the flow control device 5 in order to switch it to the open state. The mass flow can be determined by an electrical power output by the fuel cell arrangement 210.

In step Y7, a pressure curve in the high-pressure line system 2 is recorded during the removal (step Y6) of the predetermined mass flow. For example, the first pressure sensor 4 can continuously record the pressure in the high-pressure line system 2 and transmit it to the control device 6, so that the control device 6 records the pressure curve.

In step Y8, the recorded pressure curve is compared with a reference pressure curve that depends on the mass flow removed, in particular by the control device 6. The reference pressure curve can depend in particular on the filling pressure that was reached in steps Y1 -Y3. Comparing the recorded pressure curve with the reference pressure curve can in particular comprise determining a pressure gradient of the recorded pressure curve and comparing it with a reference pressure gradient of the reference pressure curve. When gas is removed from the tanks 1, the pressure in the high-pressure line system 2 drops continuously as the tanks 1 are emptied. The resulting pressure gradient depends on the filling pressure, whereby, if all tanks 1 are evenly filled, the gas mass in the tanks 1 can be approximately calculated from the filling pressure at a known temperature, e.g. using the ideal gas equation. If a known mass flow is taken from the system 100, a typical decreasing pressure curve (reference pressure curve) results in the high-pressure line system 2. However, if one of the tanks 1 was not completely filled or, in extreme cases, was hardly filled at all because the pressure loss at the associated first valve device 3 was very high during filling (step Y1), the pressure in the high-pressure line system 2 drops faster than would be expected with the known mass flow. The amount of the pressure gradient In this case, the pressure gradient deviates from the value of the reference pressure curve by more than one threshold value.

If it is determined in step Y8 that the recorded pressure curve is outside a predetermined tolerance range around the reference pressure curve, e.g. because the pressure gradient of the recorded pressure curve deviates from the reference pressure gradient by more than a threshold value, as shown in Fig. 6 by the symbol "+", the method goes to step Y9. Otherwise, the method Y can be terminated, e.g. (block E), as shown in Fig. 6 by the symbol.

In step Y6, the control device 6 generates an error signal. For example, this can include writing an error entry into the data memory 62 by the computing unit 61. Alternatively or additionally, the control device 6, in particular the computing device, can output a warning signal, e.g. in the form of an acoustic or optical warning signal.

The method Y shown schematically in Fig. 6 enables a simple and efficient detection of inadmissibly high pressure losses at the first valve devices 3 when filling the tanks 1.

The methods U, V, W, X, Y shown in Figs. 2 to 6 represent various possibilities for detecting the presence of an impermissibly high pressure loss at one of the first valve devices 3 during the filling of the gas tank system 100. The methods V, W, X, Y of Figs. 3 to 6 and the variant of the method U from Fig. 2, in which the steps U42, U52 and U62 are carried out, are not dependent on detecting the pressure in the tanks 1. The methods U, V, W, X, Y shown in Figs. 2 to 6 can also be carried out in combination.

Although the present invention has been explained above using exemplary embodiments, it is not limited thereto, but can be modified in many ways. In particular, combinations of the above exemplary embodiments are also conceivable.

Claims

Expectations

1 . Method (U) for monitoring a filling of a gas tank system (100), comprising:

Supplying (U1) gas into a tank (1) of the gas tank system (100) via a high-pressure line system (2) which is connected to the tank (1) via a valve device (3) in the open state; detecting (U2) a first pressure in the high-pressure line system (2) over a predetermined detection period during the supply (U1) of gas into the tank (1);

Determining (U3) a pressure gradient in the high-pressure line system from the measured pressure;

detecting (U41) a second pressure or detecting (U42) a temperature in the tank (1) during the detection period;

Determining (U51) a pressure difference between the first and second pressures or determining (U52) a temperature change during the detection period; and

Comparing (U61) the determined pressure difference with a pressure threshold value dependent on the first pressure and the pressure gradient or comparing (U62) the determined temperature change with a temperature change threshold value dependent on the first pressure and the pressure gradient; and

Generating (U7) an error signal by means of a control device (6) if the determined pressure difference exceeds the pressure threshold value or the determined temperature change falls below the temperature change threshold value.

2. Method (V) for monitoring a filling of a gas tank system (100), comprising:

Detecting (V1) a first pressure in a high-pressure line system (2) which is connected to a tank (1) of the gas tank system (100) via a valve device (3); Detecting (V2) a first temperature in the tank (1); supplying (V3) gas into the tank (1) via the high-pressure line system (2);

Stop (V4) the gas supply;

Detecting (V5) a second pressure in the high pressure line system (2) after stopping (V4) the gas supply;

Detecting (V6) a second temperature in the tank (1) after stopping (V4) the gas supply;

Determining (V7) a pressure change in the high-pressure line system (2) from the first and the second pressure, and a temperature change in the tank (1) from the first and the second temperature;

Comparing (V8) the determined temperature change with a temperature change threshold value dependent on the determined pressure change; and generating (V9) an error signal by means of a control device (6) if the determined temperature change falls below the temperature change threshold value. Method (V) according to claim 2, wherein the temperature change threshold value additionally depends on one or more of the following boundary conditions: the first pressure, the first temperature, the ambient temperature. Method (U, V) according to one of the preceding claims, wherein the gas tank system (100) has a plurality of tanks (1), each of which is connected to the high-pressure line system (2) via a valve device (3) and to all of which gas is supplied via the high-pressure line system (2), wherein a maximum permissible difference in the temperature changes in the individual tanks (1) is used as the temperature threshold value, and wherein comparing (U62, V8) the determined temperature change with the temperature change threshold value comprises determining a difference in the temperature changes of the individual tanks (1) and comparing it with the maximum permissible difference. Method (W) for monitoring a filling of a gas tank system (100) with several tanks (1), comprising:

Supplying (W1) gas into the tanks (1) via a high-pressure line system (2) which is connected to each tank (1) via a valve device (3) in the open state;

Stopping (W2) the gas supply to the high-pressure line system (2); detecting (W3) a pressure in the high-pressure line system (2);

Determining (W4) a pressure gradient in the high-pressure line system (2) from the detected pressure at least for a period of time after stopping (W2) the gas supply;

Comparing (W5) the pressure gradient determined for the period after stopping (W2) the gas supply with a threshold value; and generating (W6) an error signal by means of a control device (6) if the determined pressure gradient is negative and an amount of the determined pressure gradient exceeds the threshold value. Method (X) for monitoring a filling of a gas tank system (100) with several tanks (1), comprising:

Supplying (X1) gas into the tanks (1) via a high-pressure line system (2) which is connected to each tank (1) via a valve device (3) in the open state;

Stopping (X2) the gas supply to the high pressure line system (2);

Closing (X3) the valve devices (3) so that the tanks (1) are separated from the high-pressure line system (2);

Opening (X4) the valve devices (3) so that the tanks (1) are reconnected to the high-pressure line system (2);

Detecting (X5) a temperature in each tank (1) after opening (X4) of the valve devices (3) over a predetermined detection period;

Determining (X6) a temperature change in the tanks (1) over the predetermined detection period from the detected temperatures; comparing (X7) the determined temperature changes with a temperature change threshold value; and Generating (X8) an error signal by means of a control device (6) if the temperature change in at least one tank (1) corresponds to a temperature increase and the temperature change determined for this tank (1) exceeds the temperature change threshold value. Method (Y) for monitoring a filling of a gas tank system (100) with several tanks (1), comprising:

Supplying (Y1) gas into the tanks (1) via a high-pressure line system (2) which is connected to each tank (1) via a valve device (3) in the open state;

Stopping (Y3) the gas supply to the high pressure line system (2);

Closing (Y4) the valve devices (3) so that the tanks (1) are separated from the high-pressure line system (2);

Opening (Y5) the valve devices (3) so that the tanks (1) are reconnected to the high-pressure line system (2);

Extracting (Y6) a predetermined mass flow of gas from the tanks (1) via the high-pressure line system (2);

Detecting (Y7) a pressure curve in the high-pressure line system (2) during the extraction (Y6) of the predetermined mass flow; comparing (Y8) the detected pressure curve with a reference pressure curve dependent on the extracted mass flow; and generating (Y9) an error signal by means of a control device (6) if the detected pressure curve lies outside a predetermined tolerance range around the reference pressure curve. Method (Y) according to claim 7, additionally comprising:

Detecting (Y2) a filling pressure in the high-pressure line system (2) during the supply (Y1) of gas (1) into the tanks (1); wherein the gas supply is stopped (Y3) when the detected filling pressure reaches a reference value; and wherein the reference pressure curve depends on the filling pressure. Method (Y) according to claim 7 or 8, wherein the comparison (Y8) of the detected pressure curve with the reference pressure curve comprises determining a pressure gradient of the detected pressure curve and comparing it with a reference pressure gradient of the reference pressure curve, wherein the error signal is generated if the pressure gradient of the detected pressure curve deviates from the reference pressure gradient by more than a threshold value. Gas tank system (100), in particular for a fuel cell system (200), comprising: a plurality of tanks (1) for receiving gas; a high-pressure line system (2); a number of valve devices (3) corresponding to the number of tanks (1), each of which can be switched between an open state in which it connects the respective tank (1) to the high-pressure line system (2) and a closed state in which it separates the respective tank (1) from the high-pressure line system (2); a first pressure sensor (4) for detecting a pressure in the high-pressure line system (2); a number of second pressure sensors (7) and/or temperature sensors (9) corresponding to the number of tanks (1) for detecting a pressure and/or a temperature in each tank (1); a supply connection (20) connected to the high-pressure line system (2) for connecting a refueling system; and a control device (6) which is connected in a signal-conducting manner to the valve devices (3), the first pressure sensor (4) and the second pressure sensors (7) and/or the second temperature sensors (9) and is designed to cause the gas tank system (100) to carry out a method (M, V, W, X, Y) according to one of the preceding claims.