Method for the operation of a tank unit for storing a gaseous fuel, and tank unit for storing a gaseous fuel

Abstract

The present invention relates to a method for operating a tank unit (1) for storing a gaseous fuel for a vehicle. The invention also relates to a tank unit (1) for storing a gaseous fuel for a vehicle (F), comprising at least one tank vessel (TB1, TB2, ..., TBn) and at least one valve mechanism.

Description

[0001] Description

[0002] title

[0003] Procedure for operating a to save a

[0004] Gas fuel and for storing a gas fuel

[0005] The present invention relates to a method for operating a tank device for storing a gas fuel and a tank device for storing a gas fuel.

[0006] State of the art

[0007] Safety devices and / or valves can be installed in known pressure storage tanks. Fuel cell systems with tank assemblies or tanks for gaseous media are known for this purpose. To stabilize pressure storage tanks in the event of an increase in the temperature of the storage medium or a leak, and to prevent or at least reduce the escape of gas, they can be equipped with valves, for example. However, it may also be desirable to obtain better knowledge of the tank fill level of tank devices and of leaks in order to better operate the vehicle and its fuel supply in an operating state.

[0008] In conventional H2 tank systems with multiple gas tanks, each equipped with its own tank valve, not all tanks are necessarily equipped with their own pressure sensor. DE112006003013B4 describes a tank with a fitting and a valve, with the valve mounted inside the fitting.

[0009] Disclosure of the invention

[0010] The present invention provides a method for operating a tank device for storing a gas fuel according to claim 1 and a tank device for storing a gas fuel according to claim 12.

[0011] Preferred further training is the subject of the subclaims.

[0012] Advantages of the invention

[0013] The idea underlying the present invention is to provide a method for operating a tank device for storing a gas fuel and a tank device for storing a gas fuel, wherein localization and detection of leaks in a tank device can be improved.

[0014] According to the invention, the localization and detection of leaks in a high-pressure region and / or a medium-pressure region can be advantageously improved, wherein one or more tank containers can belong to the high-pressure region. For this purpose, the one or more tank containers can each comprise a temperature sensor.

[0015] According to the invention, the method for operating a tank device comprises stopping a gas discharge from the medium-pressure region of the gas line system; detecting a first pressure in the high-pressure region by means of the first pressure sensor and first temperatures in the high-pressure region and a second pressure in the medium-pressure region by means of the second pressure sensor and second temperatures in the medium-pressure region; determining an average temperature in the medium-pressure region and an average temperature in the high-pressure region based on the determined first and second

[0016] Temperatures; determining a first reference density in the high pressure region based on the first pressure and the average temperature in the high pressure region and a second reference density in the medium pressure region based on the second pressure and the average temperature in the medium pressure region; re-detecting the first pressure, the first temperatures, the second pressure, and the second temperatures in the high pressure region and in the medium pressure region before another gas withdrawal from the medium pressure region of the gas line; determining current mean values ​​of the temperatures in the medium pressure region and in the high pressure region from the re-detected first and second temperatures; determining a current density in the high pressure region and in the medium pressure region from the current mean values ​​of the temperatures and the first and second pressures;and comparing the current density in the high pressure region and in the medium pressure region with the respective reference density and verifying a deviation between the respective current density and the reference density with regard to a leak in the high pressure region and / or the medium pressure region according to a predetermined verification rule;

[0017] The tank device comprises at least one tank container with at least one valve device; a gas line system to which the at least one tank container is connected via the valve device; a first pressure sensor in a high-pressure region and a second pressure sensor in a medium-pressure region of the gas line system, wherein the respective tank container is connected to the high-pressure region of the gas line system and the high-pressure region is connected to the medium-pressure region by a control valve; and a control device which is connected to the pressure sensors and the at least one valve device.

[0018] The method according to the invention advantageously allows a leak in the tank device to be detected when the vehicle and / or consumer system is at a standstill. Advantageously, a consumer of the gaseous fuel can be shut off, in other words, a valve to the consumer and / or a valve on the tank container and the gas line system can be closed. For example, the consumer can be switched off with regard to its operation (in the shut-off state) and / or a valve on the anode side of a fuel cell can be closed, for example, if the consumer corresponds to a fuel cell (here, the so-called ASV, i.e., the anode shut-off valve, can be closed).

[0019] It is advantageous to evaluate the pressure sensors in the high pressure and medium pressure ranges and the temperature sensors in the tank container(s).

[0020] The wording of the respective tank container can also be replaced by “one tank container” or “all tank containers” within the meaning of the invention, as can the tank level.

[0021] The average temperatures can be determined via the tank containers and / or via selected points in the piping system, i.e. temporally and / or spatially.

[0022] Sensors (for pressure and temperature) can be present in the tank and in the high-pressure and / or medium-pressure areas, whereby temperature values ​​can be retrieved. On the other hand, or in addition, ambient temperatures can also be determined, for example, with a sensor, or via a model, or via data exchange with a data platform. Such temperature determination can also apply to all other temperatures in and around the tank device. In this case, the ambient temperature can be used to determine the density before the valves are reopened, for example, when the system is equilibrated with the ambient temperature.

[0023] The comparison densities can refer to an expected density at the respective operating point (e.g. also at standstill), also taking into account the prevailing boundary conditions such as ambient temperatures or fill level or other factors.

[0024] According to a preferred embodiment of the method, a pressure reduction in the high-pressure region occurs after the valve device between the gas line system and the at least one tank container is closed, before gas consumption is shut down. A targeted partial pressure reduction (pressure reduction) in the high-pressure region can advantageously occur before or during shut-down, which can be achieved, for example, by allowing the consumer to continue running after the valve devices on the tank container(s) are closed.Furthermore, or additionally, the temperature profile at the tank containers and / or in the piping system (high-pressure and / or medium-pressure range) can then be determined over a predetermined downtime, whereby a control device can be regularly woken up at defined intervals and the determined temperatures can be measured and / or saved over a day and / or night time. Furthermore or alternatively, temperature information can be provided via a data exchange platform, so-called connected services, taking the location of the vehicle into account. In this way, temperatures in the high-pressure and / or medium-pressure range can be determined using a model or sensors, and an average temperature in the respective range can be recognized.

[0025] According to a preferred embodiment of the method, the predetermined verification rule relates to an increase in density in the high-pressure region, and in this case, a leak in the valve device is concluded.

[0026] According to a preferred embodiment of the method, the predetermined verification rule relates to a density reduction in the high-pressure region, and from this a leak in the high-pressure region is concluded, wherein an additional density increase in the medium-pressure region is concluded to be an internal leak in the control valve between the high-pressure region and the medium-pressure region.

[0027] According to a preferred embodiment of the method, the predetermined verification rule relates to an increase in density in the medium-pressure range, and in doing so, refilling or a leak at the control valve between the high-pressure range and the medium-pressure range is inferred. According to a preferred embodiment of the method, the predetermined verification rule relates to a reduction in density in the medium-pressure range, and in doing so, a leak in the medium-pressure range is inferred. In the case of an additional change in density at an inlet of the consumer, a fault at the consumer is inferred, and in the absence of a change in density at the inlet of the consumer, a leak at the medium-pressure range relative to the environment is inferred.

[0028] According to a preferred embodiment of the method, a pressure and temperatures in the high-pressure range and in the medium-pressure range are determined by the pressure sensors and by temperature sensors in the high-pressure range and / or in the medium-pressure range and / or by a temperature model for the high-pressure range and for the medium-pressure range over predetermined times and predetermined time intervals and / or information about an ambient temperature is determined from a data platform.

[0029] According to a preferred embodiment of the method, it is determined whether a pressure relief valve connecting the medium-pressure region to the environment was opened during a rest phase between the switching off of the gas extraction and the renewed gas extraction, wherein a pressure profile and a temperature profile in the medium-pressure region are determined over predetermined points in time and the temperature profile determined therefrom is compared with temperature values ​​and the pressure profile determined with pressure values ​​for triggering a pressure relief valve and a conclusion is drawn from this as to a prevailing condition for opening the pressure relief valve.

[0030] According to a preferred embodiment of the method, a normally expected density in the medium-pressure range is determined by determining a lowest temperature in the medium-pressure range during a predetermined period of time after the gas extraction is stopped and before the gas extraction is resumed, as well as a pressure when the control valve closes between the high-pressure range and the medium-pressure range. According to a preferred embodiment of the method, an internal leak in the control valve between the high-pressure range and the medium-pressure range is detected if a density in the medium-pressure range is higher than the normally expected density in the medium-pressure range.

[0031] According to a preferred embodiment of the method, the determination of an average temperature is carried out using a temperature model.

[0032] The gas line can be used to supply the gas fuel to the tank containers and also to transport the gas from the tank containers to the vehicle's engine or fuel cell. The valve device can comprise a closable valve that can be opened and closed electrically.

[0033] The vehicle may be a fuel cell vehicle. The gas fuel may be a gaseous fuel used to power a fuel cell, such as hydrogen or other suitable gases. Alternatively, the gas fuel may also be a gas used in a gas-powered vehicle, such as CNG or LPG, which may also be liquefied petroleum gas.

[0034] Vehicles with a fuel cell system may have tanks filled with gas fuel, whereby the tank(s) may be under high pressure (up to approximately 700 bar nominally). During the standstill of a vehicle with an H2 storage system, different pressures may develop in the individual tanks. This is caused by different temperature changes in the individual tanks, for example, due to different heating or cooling due to different tank designs or different environmental conditions at the tanks. These differences or effects can be taken into account for individual tanks.

[0035] The tank device can also be characterized by the features and advantages mentioned in connection with the method and vice versa. According to the invention, the tank device for storing a gas fuel for a vehicle comprises at least one tank container with at least one valve device; a gas line system to which the at least one tank container is connected via the valve device; a first pressure sensor in a high-pressure region and a second pressure sensor in a medium-pressure region of the gas line system, wherein the respective tank container is connected to the high-pressure region of the gas line system and the high-pressure region is connected to the medium-pressure region by a control valve; a control device which is connected to the pressure sensors and the at least one valve device and is configured to carry out a method according to the invention.

[0036] Advantageously, a density determination can be carried out in the high-pressure range and in the medium-pressure range at a time after the consumer has been shut down. For this purpose, a pressure and a temperature can be measured in the high-pressure range. Afterward, an average temperature for the high-pressure range and / or for the medium-pressure range can be determined based on an existing sensor and / or a temperature model, which can be achieved, for example, under

[0037] Gas temperatures, ambient temperature, or other environmental or operating parameters can be taken into account. In a further step, the gas densities for the high-pressure range and / or the medium-pressure range can be memorized or stored in the control unit (e.g., in its memory) after shutdown. Furthermore, a new density determination can be performed in the high-pressure range and / or medium-pressure range before the valves on the tank containers or to the consumer are opened (during the next vehicle start-up).

[0038] Furthermore, an evaluation of the density change in the high-pressure range and / or the medium-pressure range can be carried out. For this purpose, if an increase in density is detected in the high-pressure range, it can be concluded that one or more valves are leaking (internal leak). In connection with this conclusion, a targeted reduction in the pressure in the piping system may be necessary. If a reduction in density is detected in the high-pressure range, it can be concluded that there is a leak from the high-pressure range (external leak), in which case further evaluation can be carried out. For this further evaluation, it can be determined whether there is a leak in the high-pressure range without an increase in density in the medium-pressure range, which then suggests an external leak from the high-pressure range (to the environment).On the other hand, it can then be determined if there is a leak in the high pressure area with an increase in density in the medium pressure area, which then suggests an internal leak at the control valve between the high pressure area and the medium pressure area.

[0039] With regard to the medium-pressure range, it can be determined whether there is an increase in density in the medium-pressure range, which could then indicate refilling or a leak through the control valve. Furthermore, if there is a reduction in density in the medium-pressure range, a leak from the medium-pressure range can be concluded. Further evaluation can then be carried out. If there is a leak in the medium-pressure range without a change in density or without leak detection in the inlet area of ​​a fuel cell (downstream of the anode shut-off valve ASV), an external leak from the medium-pressure range upstream of the fuel cell can be concluded. If a leak in the medium-pressure range can be detected with a change in density or leak detection in the area of ​​the fuel cell, a fault in the fuel cell can be concluded.

[0040] Furthermore, a normal expected density (for the current operating point, e.g., taking into account the existing system operating parameters) can be determined in the medium-pressure range, for example, for a predetermined time or period, without assuming an internal leak at the control valve. This can result from a closing pressure of the pressure regulator (control valve) and a lowest temperature during standstill, whereby a determination of the temperature profile in the high-pressure range and / or medium-pressure range may be necessary. For this purpose, a case-by-case distinction can be made.

[0041] If the density at the time before the valve on the tank container or towards the consumer is opened during the next commissioning of the consumer corresponds to the normally expected density in the medium pressure range, there is probably no internal leakage of the control valve (only normal refilling is present) and the determined mass reduction in the high pressure range corresponds to the mass increase in the medium pressure range, then the condition "no external leakage in the high pressure range and medium pressure range" can be concluded.

[0042] If the density prior to opening the valves during the next commissioning is higher than the "normally expected density in the medium-pressure range," this is assumed to be due to an internal leak in the control valve. In this case, a mathematical assessment of the control valve leak can be performed, taking into account the change in density, the volume of the medium-pressure range (its change), and the time since the lowest temperature.

[0043] If the density at the time before the valves are opened during the next commissioning corresponds to the "normally expected density in the medium-pressure range," there is probably no internal leakage of the control valve (only normal refilling), and the determined mass reduction in the high-pressure range may be greater than the mass increase in the medium-pressure range with a predetermined threshold. In this case, an "external leakage from the high-pressure range" can also be inferred.

[0044] If the density prior to the valve opening during the next start-up is lower than the "normally expected density in the medium-pressure range," an external leak from the medium-pressure range can be assumed. In this case, a mathematical assessment of an external leak can be performed, taking into account the density change in the medium-pressure and high-pressure ranges, the volumes in the medium-pressure and high-pressure ranges (and their changes), and the time since shutdown.

[0045] As a supplementary procedure for the verification, it can be determined whether a pressure relief valve (PRV) was open during a shutdown, whereby the determination of the temperature curve may be necessary for this step and / or a temperature determination may be available via data exchange of the connected services.

[0046] This can be done by determining whether the density at the time before the valves open (of the valve) is higher than the "normally expected density in the medium-pressure range" during the next start-up. This can then be used to conclude that there is an internal leak in the control valve. For this purpose, a mathematical evaluation of the maximum pressure during standstill can be performed based on the determined density in the medium-pressure range before start-up and the maximum temperature encountered during standstill.

[0047] The maximum pressure during standstill can then be compared with a threshold stored in the control device for the minimum closing pressure of the pressure relief valve. If the calculated maximum pressure is greater than or equal to a threshold, it may be possible to infer an external leak due to the PRV opening. Furthermore, a supplementary method can be used to check whether the PRV was open during standstill; for this purpose, it may be necessary to determine the temperature curve using the wake-up approach. With the wake-up approach, in addition to the temperature, the pressure in the medium-pressure range can also be measured. If one of the measured pressures is greater than or equal to the threshold, it may be possible to infer an external leak due to the PRV opening.

[0048] The high-pressure area can be located upstream of the regulator toward the tank containers. The medium-pressure area can be located between the regulator and the consumer, such as the fuel cell.

[0049] Further features and advantages of embodiments of the invention will become apparent from the following description with reference to the accompanying drawings.

[0050] Brief description of the drawing The present invention is explained in more detail below with reference to the embodiment shown in the schematic figure of the drawing.

[0051] They show:

[0052] Fig. 1 is a schematic representation of a tank device for storing a gas fuel for a vehicle according to an embodiment of the present invention.

[0053] In the figures, the same reference symbols denote the same or functionally identical elements.

[0054] Fig. 1 shows a schematic representation of a tank device for storing a gas fuel for a vehicle according to an embodiment of the present invention.

[0055] The tank device 1 comprises at least one tank container (TB1, TB2, ..., TBn) with at least one valve device; a gas line system GL, to which the at least one tank container (TB1, TB2, ..., TBn) is connected via the valve device; a first pressure sensor in a high-pressure region and a second pressure sensor in a medium-pressure region of the gas line system GL, wherein the respective tank container (TB1, TB2, ..., TBn) is connected to the high-pressure region of the gas line system GL and the high-pressure region is connected to the medium-pressure region by a control valve; a control device which is connected to the pressure sensors and the at least one valve device and is designed to carry out a method according to the invention. In the method, gas discharge from the medium-pressure region of the gas line system is stopped;detecting a first pressure in the high-pressure region by means of the first pressure sensor and first temperatures in the high-pressure region and a second pressure in the medium-pressure region by means of the second pressure sensor and second temperatures in the medium-pressure region; determining an average temperature in the medium-pressure region and an average temperature in the high-pressure region based on the determined first and second temperatures; determining a first reference density in the high-pressure region based on the first pressure and the average temperature in the high-pressure region and a second reference density in the medium-pressure region based on the second pressure and the average temperature in the medium-pressure region; re-detecting the first pressure, the first temperatures, the second pressure, and the second temperatures in the high-pressure region and in the medium-pressure region before another gas extraction from the medium-pressure region of the gas line;determining current mean values ​​of the temperatures in the medium-pressure region and in the high-pressure region from the newly acquired first and second temperatures; determining a current density in the high-pressure region and in the medium-pressure region from the current mean values ​​of the temperatures and the first and second pressures; and comparing the current density in the high-pressure region and in the medium-pressure region with the respective reference density and verifying a deviation between the respective current density and the reference density with regard to a leak in the high-pressure region and / or the medium-pressure region according to a predetermined verification rule;

[0056] Fig. 1 shows a system comprising a hydrogen storage device with a tank device 1 and a fuel cell device BZE.

[0057] The majority of the tank containers TB1, TB2, ... is symbolically represented as a tank, which can be connected to a safety valve SV, for example a thermally operated safety valve, and to a shut-off valve 2. One tank side TS (for example towards a filling station) can be connected to the tank TB1, ... by means of a check valve RSV. The shut-off valve can be connected to the fuel cell BZ in the fuel cell device BZE by means of a regulator R, in particular via a gas line GL. The gas line GL itself can have the sensor Si on the high pressure side, i.e. upstream of the regulator in the flow direction, wherein the side at the fuel cell, i.e. downstream of the regulator R, can also have such a pressure and / or temperature sensor Si. The fuel cell BZ can be connected to a blower GB and to an exhaust gas area AB.The fuel cell can subsequently supply an energy management system D, for example, with a battery Batt, one or more capacitors C, an associated control device D-SE, and drive a motor M. The high-pressure region can be located upstream of the regulator R toward the tank containers. The medium-pressure region can be located between the regulator R and the consumer, such as the fuel cell.

[0058] Although the present invention has been fully described above using the preferred embodiment, it is not limited thereto but can be modified in many ways.

Claims

Claims 1. A method for operating a tank device (1) for storing a gaseous fuel for a vehicle, wherein the tank device (1) comprises: at least one tank container (TB1, TB2, TBn) with at least one valve device; a gas line system (GL) to which the at least one tank container (TB1, TB2, ..., TBn) is connected via the valve device; a first pressure sensor in a high-pressure region and a second pressure sensor in a medium-pressure region of the gas line system (GL), wherein the respective tank container (TB1, TB2, ..., TBn) is connected to the high-pressure region of the gas line system (GL) and the high-pressure region is connected to the medium-pressure region by a control valve; and a control device connected to the pressure sensors and the at least one valve device; the method comprising the steps: - stopping the release of gas from the medium pressure area (MD) of the gas pipeline system (GL); - detecting a first pressure in the high pressure range by means of the first pressure sensor and first temperatures in the high pressure range and a second pressure in the medium pressure range by means of the second pressure sensor and second temperatures in the medium pressure range; - determining an average temperature in the medium pressure region and an average temperature in the high pressure region based on the first and second temperatures determined; - determining a first reference density in the high pressure region based on the first pressure and the average temperature in the high pressure region and a second reference density in the medium pressure region based on the second pressure and the average temperature in the medium pressure region; - re-measuring the first pressure, the first temperatures, the second pressure and the second temperatures in the high-pressure and medium-pressure regions before a new gas extraction from the medium-pressure region of the gas line; - Determining current mean values ​​of the temperatures in the medium pressure range and in the high pressure range from the newly recorded first and second temperatures; Determining a current density in the high pressure region and in the medium pressure region from the current mean values ​​of the temperatures and the first and second pressures; and - Comparing the current density in the high pressure region and in the medium pressure region with the respective reference density and verifying a deviation between the respective current density and the reference density with regard to a leak in the high pressure region and / or the medium pressure region according to a predetermined verification rule.

2. Method according to claim 1, in which a pressure reduction in the high-pressure region takes place after closing of the valve device between the gas line system and the at least one tank container before the gas consumption is stopped.

3. Method according to claim 2, wherein the predetermined verification rule relates to an increase in density in the high-pressure region and thereby concludes that there is a leak in the valve device.

4. Method according to one of claims 1 to 3, in which the predetermined verification rule relates to a density reduction in the high-pressure region and a leak in the high-pressure region is inferred therefrom, wherein an additional density increase in the medium-pressure region is inferred to be an internal leak in the control valve between the high-pressure region and the medium-pressure region.

5. Method according to one of claims 1 to 4, wherein the predetermined verification rule relates to an increase in density in the medium-pressure range and thereby infers a refilling or a leak at the control valve between the high-pressure range and the medium-pressure range.

6. Method according to one of claims 1 to 5, in which the predetermined verification rule relates to a density reduction in the medium-pressure range and in this case a leak in the medium-pressure range is inferred, wherein in the case of an additional density change at an inlet of the consumer a fault is inferred at the consumer and in the case of an absence of a density change at the inlet of the consumer a leak at the medium-pressure range with respect to an environment is inferred.

7. Method according to one of claims 1 to 6, in which a determination of a pressure and of temperatures in the high-pressure range and in the medium-pressure range is carried out by the pressure sensors and by temperature sensors in the high-pressure range and / or in the medium-pressure range and / or by a temperature model for the high-pressure range and for the medium-pressure range over predetermined times and predetermined time intervals and / or information about an ambient temperature is determined from a data platform.

8. Method according to one of claims 1 to 7, in which it is determined whether a pressure relief valve which connects the medium-pressure region to the environment has been opened during a rest phase between the switching off of the gas extraction and the renewed gas extraction, wherein a pressure profile and a temperature profile in the medium-pressure region are determined over predetermined times and the temperature profile determined therefrom are compared with temperature values ​​and the pressure profile determined with pressure values ​​for triggering a pressure relief valve and a conclusion is drawn therefrom as to a prevailing condition for opening the pressure relief valve.

9. Method according to claim 7 or 8, in which a normally expected density in the medium pressure range is determined by determining a lowest temperature at the medium pressure range during a predetermined period of time after the gas extraction has been stopped and before the gas extraction is restarted, as well as a pressure when the control valve is closed between the high pressure range and the medium pressure range.

10. Method according to claim 8 and 9, wherein an internal leak of the control valve between the high pressure area and the medium pressure area is detected when a density at the medium pressure area is higher than the normally expected density is increased in the medium pressure range.

11. Method according to one of claims 1 to 10, wherein the determination of an average temperature is carried out using a temperature model.

12. Tank device (1) for storing a gaseous fuel for a vehicle (F), comprising: at least one tank container (TB1, TB2, ..., TBn) with at least one valve device; a gas line system (GL) to which the at least one tank container (TB1, TB2, ..., TBn) is connected via the valve device; a first pressure sensor in a high-pressure region and a second pressure sensor in a medium-pressure region of the gas line system (GL), wherein the respective tank container (TB1, TB2, ..., TBn) is connected via the valve device to the high-pressure region of the gas line system (GL) and the high-pressure region is connected from the medium-pressure region by a control valve; a control device which is connected to the pressure sensors and the at least one valve device and is configured to carry out a method according to one of claims 1 to 11.

13. Tank device (1) according to claim 12, wherein the control device is connectable to a fuel cell of the vehicle and is configured to determine a necessary gas consumption for a generated power of the fuel cell from the fuel cell.

14. Tank device (1) according to claim 12 or 13, which comprises a plurality of temperature sensors in the high pressure range and one or a plurality of temperature sensors in the medium pressure range.

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