Method and apparatus for determining the pressure in a pressure vessel

Abstract

The technology disclosed herein relates to a device (101) for determining pressure information relating to the fuel pressure of fuel in a pressure vessel (110) of a pressure vessel system (100), wherein the pressure vessel system (100) is configured to convey fuel from the pressure vessel (110) via a pressure transducer (120) to an energy converter (102), and wherein the pressure vessel system (100) has a low-pressure sensor (122) on a low-pressure side of the pressure transducer (120). The device (101) is configured to determine that a measurement operating condition of the pressure vessel system (100) exists and to acquire a measured value of the fuel pressure on the low-pressure side of the pressure transducer (122) using the low-pressure sensor (122). The device (101) is further configured to determine the pressure information relating to the fuel pressure in the pressure vessel (110) based on the measured value of the low-pressure sensor (122).

Description

[0001] The technology disclosed here relates to a method and a corresponding device designed to determine pressure information relating to the fuel pressure of fuel in a pressure vessel, in particular to ensure safe operation of the pressure vessel.

[0002] A road vehicle may have a fuel cell stack that generates electrical energy for the operation, in particular for propulsion, of the vehicle based on a fuel such as hydrogen. The fuel may be stored in one or more pressure vessels of a pressure vessel system of the vehicle and can be supplied to the fuel cell stack via lines as needed. The pressure vessel system typically includes a pressure sensor configured to detect measured values ​​relating to the fuel pressure of the fuel in the one or more pressure vessels.

[0003] The one or more pressure vessels of the pressure vessel system and the pressure sensor can each be designed for a nominal pressure of 350 barg or more, or 700 barg or more. The measurement error of a pressure sensor is typically proportional to the nominal pressure for which the pressure sensor is designed (e.g., 1-2% of the nominal pressure or full-scale pressure). The measured value of the pressure sensor can therefore have a measurement error of 10-20 bar. In a situation with a relatively low fuel pressure, this can lead to the fuel pressure being determined only with relatively low accuracy.

[0004] A preferred object of the technology disclosed here is to reduce or eliminate at least one disadvantage of a previously known solution or to propose an alternative solution. A preferred object of the technology disclosed here is to enable efficient and precise determination of the fuel pressure in a pressure vessel of a pressure vessel system.

[0005] The problem(s) are solved by the subject matter of the independent patent claims. The dependent claims represent preferred embodiments.

[0006] According to one aspect, a device for determining pressure information relating to the fuel pressure of fuel in a pressure vessel of a pressure vessel system is described. The pressure information can optionally be used to determine the remaining amount of fuel in the pressure vessel (e.g., based on a predefined model). The fuel quantity can be used to determine or estimate the range of a vehicle in which the pressure vessel system is installed. Alternatively or additionally, the pressure information can be used to check whether the fuel pressure reaches the permissible minimum pressure of the pressure vessel or not.

[0007] The pressure vessel system may comprise one or more pressure vessels for storing the fuel (in particular hydrogen, such as H2, or compressed natural gas (CNG)). The pressure vessel system may be part of a higher-level system (e.g., a vehicle). The higher-level system (or the pressure vessel system) may comprise an energy converter configured to generate electrical energy for operating the higher-level system based on fuel from the pressure vessel system. In a preferred example, the higher-level system is a motor vehicle (such as a passenger car, a truck, a motorcycle, a bus, etc.). The generated electrical energy may be used to operate an electric drive motor of the motor vehicle.

[0008] The pressure vessel system can be used in particular for storing fuel that is gaseous under ambient conditions. The pressure vessel system can be used, for example, in a motor vehicle that is powered by compressed (also called compressed natural gas or CNG) or liquefied (also called liquid natural gas or LNG) natural gas or by hydrogen (in particular H2) as fuel. The pressure vessel system is typically fluidly connected to at least one energy converter that is designed to convert chemical energy of the fuel into one or more other forms of energy, for example into electrical energy and / or kinetic energy. The energy converter can be, for example, an internal combustion engine or a fuel cell system or a fuel cell stack with at least one fuel cell.

[0009] The pressure vessel system typically comprises at least one pressure vessel, in particular a composite overwrapped pressure vessel. The pressure vessel can be, for example, a cryogenic pressure vessel or a high-pressure gas vessel.

[0010] High-pressure gas cylinders are designed to permanently store fuel at ambient temperatures at a nominal working pressure (also called nominal working pressure or NWP) of at least 350 bar (= overpressure compared to atmospheric pressure) or at least 700 bar (= overpressure above atmospheric pressure). A cryogenic pressure cylinder is suitable for storing fuel at the aforementioned operating pressures even at temperatures that are significantly below the operating temperature of the vehicle (e.g., more than 50 Kelvin or more than 100 Kelvin).

[0011] The pressure vessel system comprises, for example, a line configured to conduct fuel from the pressure vessel via a pressure transducer (in particular via a pressure regulator) to the energy converter. The pressure transducer can be configured to reduce the fuel pressure. A high-pressure side can be arranged at the inlet of the pressure transducer (between the pressure vessel and the pressure transducer), which is designed for the relatively high fuel pressure of the pressure vessel.

[0012] The pressure transducer can be designed to set the fuel pressure to a specific target pressure on the low-pressure side at the outlet of the pressure transducer, in particular by (binary) opening and closing a valve and / or by varying the degree of opening of the valve. For example, the degree of opening of the valve of the pressure transducer can be varied continuously between 0% and 100%. The degree of opening can be increased if the actual pressure (i.e., the actual value of the pressure) at the outlet of the pressure transducer is less than the target pressure. Conversely, the degree of opening can be reduced if the actual pressure at the outlet of the pressure transducer is less than the target pressure. The target pressure can be lower, in particular by a factor of 2 or more, or by a factor of 5 or more, or by a factor of 10 or more, than the nominal pressure of the pressure vessel (for which the high-pressure side is designed).

[0013] The pressure vessel system includes a low-pressure sensor on the low-pressure side of the pressure transducer (i.e., on the side of the pressure transducer facing away from the high-pressure side and / or the pressure vessel). The low-pressure sensor can be designed for the target pressure of the low-pressure side.

[0014] Furthermore, the pressure vessel system can have a high-pressure sensor on the high-pressure side (between the pressure vessel and the inlet of the pressure transducer). The high-pressure sensor can be designed for the nominal pressure of the pressure vessel.

[0015] The device is configured to determine that a measuring operating situation of the pressure vessel system exists. In particular, the device can be configured to check at a check time whether a measuring operating situation exists or not. A measuring operating situation can exist, for example, when the pressure transducer is open (e.g. completely open and / or with an opening degree of 100%). This can be detected on the basis of the fuel pressure on the low-pressure side. The device can, for example, be configured, as part of the check at the check time as to whether a measuring operating situation exists or not, to compare a measured value of the low-pressure sensor, which was recorded at the check time, with the target value of the fuel pressure of the fuel on the low-pressure side.It can be determined that the pressure transducer is open when the measured value of the low pressure sensor is less than the set value of the fuel pressure of the fuel on the low pressure side.

[0016] Furthermore, a prerequisite for the existence of a measuring operating situation can be that no fuel is supplied to the energy converter. The pressure vessel system can comprise a supply valve arranged between the pressure transducer and the energy converter (in particular on the fuel supply line of the energy converter). The device can be configured to determine, as part of the check at the check time as to whether the measuring operating situation exists or not, whether the supply valve is open or closed at the check time. It can be determined that no fuel is supplied to the energy converter if it is determined that the supply valve is closed.

[0017] It can thus be checked whether a measuring operating situation of the pressure vessel system exists that is suitable for determining the pressure information based on a measured value of the low-pressure sensor.

[0018] The device is further configured to detect a measured value of the fuel pressure on the low-pressure side of the pressure transducer using the low-pressure sensor when a measuring operating situation exists. Furthermore, the device is configured to determine the pressure information relating to the fuel pressure in the pressure vessel based on the measured value of the low-pressure sensor. The pressure information can, in particular, indicate whether a specific minimum pressure threshold for the permissible minimum pressure of the pressure vessel has been reached or undershot.

[0019] The device can be configured to determine, based on the measured value of the low-pressure sensor as pressure information, whether the minimum pressure threshold for the fuel pressure in the pressure vessel has been reached or undershot. The minimum pressure threshold can, for example, be a certain safety margin higher than the permissible minimum pressure of the pressure vessel.

[0020] The device can, in particular, be configured to compare the measured value of the low-pressure sensor with the minimum pressure threshold. Depending on the comparison, it can then be determined, in particular if the measured value of the low-pressure sensor is equal to or less than the minimum pressure threshold, that the minimum pressure threshold for the fuel pressure of the fuel in the pressure vessel has been reached or undershot.

[0021] The device may further be configured to initiate one or more safety measures with respect to the pressure vessel if it is determined that the minimum pressure threshold for the fuel pressure of fuel in the pressure vessel has been reached or exceeded. Examples of safety measures include: • closing the pressure vessel shut-off valve; • deactivating the pressure vessel system, in particular the energy converter; and / or • issuing a notice to the user of the pressure vessel system.

[0022] Thus, a device is described which is designed to use one or more measured values ​​from the low-pressure sensor of the pressure vessel system when a measuring operating situation exists to determine the fuel pressure in the pressure vessel and, if necessary, to check based on this whether the permissible minimum pressure of the pressure vessel is reached. This enables particularly safe operation of the pressure vessel in a particularly efficient manner. In particular, a minimum pressure threshold value can be used which is relatively close to the permissible minimum pressure and thus has only a relatively small additional safety margin (compared to a pressure threshold value which must be used for measured values ​​from the high-pressure sensor (due to the increased measurement error)).

[0023] The device can be configured to determine that the shutoff valve of the pressure vessel is open (and thus the high-pressure side of the pressure transducer is fluidly connected to the pressure vessel). In response to this, in particular only in response to this, it can be determined that a measuring operating situation of the pressure vessel system exists. As a further prerequisite for the existence of a measuring operating situation, it may therefore be necessary for the shutoff valve of the pressure vessel to be open. This allows the fuel pressure in the pressure vessel to be determined with increased accuracy based on a measured value from the low-pressure sensor.

[0024] The device can be configured to compare a measured value from the high-pressure sensor with a pressure threshold. The pressure threshold can depend on the measurement error and / or the measurement tolerance of the high-pressure sensor. Furthermore, the pressure threshold can be greater than the permissible minimum pressure of fuel in the pressure vessel, which must not be undercut for safety reasons. Typically, the pressure threshold is greater than the minimum pressure threshold used to determine the pressure information based on the measured value from the low-pressure sensor (due to the fact that the low-pressure sensor has a higher measurement accuracy than the high-pressure sensor).

[0025] The pressure threshold may be lower than the fuel pressure setpoint on the low pressure side of the pressure transducer.

[0026] The pressure information (in particular the fact axis whether the minimum pressure of the pressure vessel is reached) can be determined based on the measured value of the high pressure sensor if the measured value of the high pressure sensor is equal to or greater than the pressure threshold value.

[0027] On the other hand, the pressure information (in particular the actual axis as to whether the minimum pressure of the pressure vessel is reached) can be determined based on the measured value of the low-pressure sensor if the measured value of the high-pressure sensor is less than the pressure threshold. In particular, the device can be configured to check, if the measured value of the high-pressure sensor is less than the pressure threshold, whether a measurement operating situation of the pressure vessel system exists in order to be able to determine the pressure information based on the measured value of the low-pressure sensor. The pressure information can be determined (possibly only) based on the measured value of the low-pressure sensor if it is determined that a measurement operating situation exists. On the other hand, the pressure information can be determined based on the measured value of the high-pressure sensor.

[0028] By taking into account a measured value from the high-pressure sensor, the pressure information can be determined with increased reliability (especially when there is no measuring operating situation).

[0029] The device can be configured to detect that a refueling process for refueling the pressure vessel with fuel is to be performed and / or that the pressure vessel system is to be deactivated. It can be checked (if necessary only) in response to the detection whether or not a measuring operating situation of the pressure vessel system exists. This allows for particularly efficient detection of the presence of a measuring operating situation.

[0030] According to a further aspect, a pressure vessel system is described, in particular for a motor vehicle. The pressure vessel system comprises the device described in this document.

[0031] According to a further aspect, a (road) motor vehicle (in particular a passenger car or a truck or a bus or a motorcycle) is described which comprises the pressure vessel system and / or the device described in this document.

[0032] According to a further aspect, a method for determining pressure information relating to the fuel pressure of fuel in a pressure vessel of a pressure vessel system is described. The pressure vessel system is configured to conduct fuel from the pressure vessel via a pressure transducer to an energy converter. The pressure vessel system has a low-pressure sensor on the low-pressure side of the pressure transducer.

[0033] The method includes determining that a measurement operating condition of the pressure vessel system exists. A measurement operating condition may exist, for example, when the pressure transducer is (fully and / or permanently) open and when no fuel is being supplied to the energy converter.

[0034] The method further comprises detecting, when the measuring operating situation is present and based on the low-pressure sensor, a measured value of the fuel pressure on the low-pressure side of the pressure transducer, and determining the pressure information with regard to the fuel pressure in the pressure vessel based on the measured value of the low-pressure sensor.

[0035] According to another aspect, a software (SW) program is described. The SW program can be configured to be executed on a processor and thereby to carry out the method described in this document.

[0036] According to a further aspect, a storage medium is described. The storage medium can comprise a software program configured to be executed on a processor and thereby to carry out the method described in this document.

[0037] It should be noted that the methods, devices, and systems described in this document can be used both alone and in combination with other methods, devices, and systems described in this document. Furthermore, any aspects of the methods, devices, and systems described in this document can be combined in a variety of ways. In particular, the features of the claims can be combined in a variety of ways. Furthermore, features listed in parentheses are to be understood as optional features.

[0038] The invention will be described in more detail below using exemplary embodiments. Fig. 1 an exemplary pressure vessel system; and Fig. 2 a flowchart of an exemplary method for determining pressure information relating to the fuel pressure in a pressure vessel.

[0039] As stated at the beginning, this document deals with the efficient and precise determination of the fuel pressure in a pressure vessel of a pressure vessel system. In this context, Fig. 1 shows an exemplary pressure vessel system 100 with a pressure vessel 110 that can be used to provide fuel (in particular hydrogen, such as H2) for an energy converter (e.g., for a fuel cell or a fuel cell stack) 102. The pressure vessel 110 is connected to the energy converter 102 via a line 112. The pressure vessel 110 can have a valve 111 through which fuel can be selectively fed from the pressure vessel 110 into the line 112.

[0040] The fuel pressure in the pressure vessel 110 can be relatively high, in particular at 500 barg or more, in order to accommodate the highest possible amount of fuel in the pressure vessel 110. On the other hand, the energy converter 102 can be operated with fuel having a relatively low pressure (e.g., 20 barg or less). The fuel line 112 between the pressure vessel 110 and the energy converter 102 can therefore have a high-pressure side and a low-pressure side, which are connected to one another via a pressure converter 120.

[0041] The fuel pressure on the high-pressure side (between the pressure vessel 110 and the pressure transducer 120) can be detected by a high-pressure sensor 121, and the fuel pressure on the low-pressure side (between the pressure transducer 120 and the energy converter 102) can be detected by a low-pressure sensor 122. The high-pressure sensor 121 is designed for at least the nominal pressure of the pressure vessel 110, e.g., 500 barg or more, or 800 barg or more. The low-pressure sensor 122 is designed for the nominal pressure of the energy converter 102, e.g., 30 barg or less. As explained above, a pressure sensor 121, 122 typically has a measurement error that is proportional to the nominal pressure of the pressure sensor 121, 122. As a result, the low pressure sensor 122 typically has a significantly smaller (absolute) measurement error than the high pressure sensor 121 (e.g., an (absolute) measurement error that is smaller by a factor of 10 or more).

[0042] The pressure vessel system 100 can have a (control) device 101 that is designed to control the valve 111 of the pressure vessel 110 and / or to detect or determine measured values ​​from the pressure sensors 121, 122. Furthermore, the device 101 can be designed to determine quantity information relating to the amount of fuel in the pressure vessel 110 based on the measured values ​​from one or more pressure sensors 121, 122. For this purpose, the device 101 can use predefined characteristic data and / or a predefined (possibly analytical) characteristic formula that makes it possible to determine the amount of fuel in the pressure vessel 110 based on the fuel pressure in the pressure vessel 110 (and possibly based on one or more further measured variables, such as the fuel temperature).

[0043] The device 101 can be configured to consider one or more measured values ​​of the low-pressure sensor 122 when determining the fuel pressure in the pressure vessel 110, particularly in a situation in which the pressure vessel 110 has a relatively low pressure. Thus, the accuracy of the determined pressure information with respect to the fuel pressure in the pressure vessel 110 can be increased, particularly in a situation in which the pressure vessel 110 only has a relatively low fuel pressure.

[0044] The pressure transducer 120 of the pressure vessel system 100 can be configured to regulate the pressure on the low-pressure side to a specific setpoint or target pressure. For this purpose, a valve of the pressure transducer 120 can be opened or closed (in particular, fully opened or fully closed). If necessary, the degree of opening of the valve of the pressure transducer 120 can be varied (continuously). By opening the valve, fuel flows from the high-pressure side to the low-pressure side, thereby increasing the pressure on the low-pressure side. The volumetric or mass flow of fuel via the valve of the pressure transducer 120 typically depends on the pressure difference between the high-pressure side and the low-pressure side.

[0045] When the pressure on the low-pressure side drops below a certain lower pressure threshold (which is typically lower than the pressure setpoint or the target pressure for the low-pressure side), the valve of the pressure transducer 120 is opened and / or the degree of opening of the valve of the pressure transducer 120 is increased so that (more) fuel flows from the high-pressure side via the pressure transducer 120 to the low-pressure side, which leads to an increase in pressure on the low-pressure side and (typically) a decrease in pressure on the high-pressure side. When the pressure on the low-pressure side rises above a certain upper pressure threshold (which is typically higher than the pressure setpoint orthe target pressure for the low-pressure side), the valve of the pressure transducer 120 is closed and / or the degree of opening of the valve of the pressure transducer 120 is reduced, which leads to a reduction in the amount of fuel flowing from the high-pressure side via the pressure transducer 120 to the low-pressure side.

[0046] In a corresponding manner, by varying the degree of opening and / or by binary opening and closing of the valve of pressure transducer 120, the pressure on the low-pressure side can be adjusted, in particular regulated, to the pressure setpoint or the target pressure. The pressure on the high-pressure side typically decreases and gradually approaches the pressure on the low-pressure side. From a certain point in time, the pressures on the high-pressure and low-pressure sides are equal, which typically results in the valve of pressure transducer 120 being permanently (fully) open (with an opening degree of 100%).

[0047] When the valve of the pressure transducer 120 is permanently (fully) open and / or when the pressures on the high pressure side and on the low pressure side are the same, the measured values ​​of the low pressure sensor 122 can be used to determine the fuel pressure in the pressure vessel 110 and / or the remaining amount of fuel in the pressure vessel 110 with increased accuracy (compared to the measured values ​​of the high pressure sensor 121).

[0048] The accuracy with which measured values ​​relating to the fuel pressure in the pressure vessel 110 can be recorded using the low-pressure sensor 122 can be further increased by preventing any possible fuel volume flow at the measuring point of the low-pressure sensor 122. This can be achieved by preventing the fuel supply to the energy converter 102, e.g., by closing a supply valve 105 on the line 112 to the energy converter 102 and / or on the fuel supply line of the energy converter 102.

[0049] The (control) device 101 of the pressure vessel system 100 can thus be configured to detect a measuring operating situation of the pressure vessel system 100 in which • the fuel supply to the energy converter 102 on the low pressure side of the fuel line 112 is blocked (e.g. because the supply valve 105 is closed); • the pressure converter 120 is permanently open (e.g., because the pressure on the low-pressure side of the fuel line 112 is less than the setpoint of the fuel pressure on the low-pressure side); and • if necessary, the tank valve 111 of the pressure vessel 110 is open.

[0050] The above-mentioned measuring operating situation can occur, for example, if the user of the pressure vessel system 100 has indicated a desire to refuel the pressure vessel 110 (e.g. by actuating a control element) and / or if the pressure vessel system 100 is switched off (e.g. upon completion of a journey of a vehicle having the pressure vessel system 100).

[0051] In such a measuring operating situation, one or more measured values ​​relating to the fuel pressure in the pressure vessel 110 (which corresponds to the pressure at the measuring point of the low-pressure sensor 122) can be recorded using the low-pressure sensor 122.

[0052] For example, a shutdown procedure of the pressure vessel system 100 can be carried out in which • first, the supply valve 105 to the energy converter 102 is closed; and • with a certain delay (ie after a certain delay time interval has elapsed) the tank and / or shut-off valve 111 of the pressure vessel 110 is closed.

[0053] During the delay time interval, the fuel pressure in the pressure vessel 110 can be determined in a particularly precise manner based on one or more measured values ​​of the low-pressure sensor 122.

[0054] The pressure vessel 110 can be designed such that the pressure in the pressure vessel 110 should not fall below a certain minimum pressure, e.g., to prevent damage to the pressure vessel 110. The measures described in this document can ensure in a particularly reliable manner that the minimum pressure of the pressure vessel 110 is not undercut. In particular, it can be ensured that the removal of fuel from the pressure vessel 110 is prevented (e.g., by closing the intake and / or shut-off valve 111) as soon as a certain lower pressure threshold is reached or undercut.

[0055] The pressure transducer 120 (also referred to as a pressure reducer) is preferably configured such that the target pressure on the low-pressure side is less than the minimum pressure of the pressure vessel 110. Furthermore, the pressure transducer 120 is preferably configured such that the pressure transducer 120 does not generate a pressure loss when the target pressure on the low-pressure side is undershot, provided there is no mass flow (via the pressure transducer 120).

[0056] If the target pressure is undershot, the pressure transducer 120 thus represents only a flow resistance. Consequently, in situations where no fuel is being drawn from the pressure vessel 110 and / or no mass flow through the pressure transducer 120 is taking place, the pressure in the pressure vessel 110 can be measured with high accuracy using the low-pressure sensor 122. As a result, the lead times in the safety function can be reduced. This, in turn, reduces the mass of fuel that cannot be drawn from the pressure vessel 110 for safety reasons. With the same volume of the pressure vessel 110, the range of the vehicle in which the pressure vessel system 100 is installed is increased.

[0057] To determine the range, the high-pressure sensor 121 is preferably included (if necessary, additionally) in order to be able to determine the vehicle's range even at a higher tank pressure (which is higher than the target pressure of the low-pressure side). However, the range determination typically does not have to meet the integrity requirements of the safety function for monitoring the minimum pressure of the pressure vessel 100. Furthermore, the larger measurement error of the high-pressure sensor 121 can be compensated for by one or more additional measures.

[0058] In an FCEV (fuel cell electric vehicle), for example, a specific measurement operating situation can be established at each end of the withdrawal of hydrogen from the pressure vessel 110 in order to be able to carry out an indirect measurement of the fuel pressure in the pressure vessel 110 via the low-pressure sensor 122 and thereby monitor the safety threshold for the minimum pressure of the pressure vessel 110.

[0059] The end of the fuel withdrawal from the pressure vessel 110 can be detected. In response, the supply valve 105 at the end of the low-pressure region upstream of the energy converter 102 (in particular, upstream of the fuel cell) can be closed. The fact that the supply valve 105 has been closed can be detected by reading back the control of the supply valve 105. The shut-off valve 111 on the pressure vessel 110 remains open (at least temporarily, for a delay interval). This can be detected by reading back the control of the shut-off valve 111.

[0060] An indirect measurement of the pressure in the pressure vessel 110 can then be performed (preferably during the delay interval) using the low-pressure sensor 122. Furthermore, the measured value of the low-pressure sensor 122 can be compared with the minimum pressure threshold of the pressure vessel 110. Depending on the result of the comparison, an error reaction can possibly be triggered. Furthermore, the shut-off valve 111 of the pressure vessel 110 can be closed (after the delay interval has elapsed).

[0061] If, during operation of the fuel cell system 100, it is detected based on one or more measured values ​​of the high-pressure sensor 121 in the high-pressure range that, taking into account the measurement tolerance of the high-pressure sensor 121, a certain pressure threshold value of the pressure vessel 110 (i.e., the safety threshold for the minimum pressure of the pressure vessel 110) has not yet been undercut, the indirect measurement via the low-pressure sensor 122 can be dispensed with. The calculation of the fill level of the pressure vessel 110 can advantageously be carried out taking into account measured values ​​from both sensors 121, 122, independently of the verification of the safety threshold.

[0062] A mechanical piston-spring pressure regulator can be used as pressure transducer 120. Such a pressure transducer 120 can be designed such that, at an inlet pressure that is lower than the control pressure (i.e., the target pressure), pressure equalization between the inlet and outlet pressures automatically occurs.

[0063] Fig. 2 shows a flowchart of a (possibly computer-implemented) method 200 for determining pressure information relating to the fuel pressure of fuel in a pressure vessel 110 of a pressure vessel system 100. As pressure information, it can be determined in particular whether the fuel pressure in the pressure vessel 110 reaches or falls below a certain minimum pressure threshold value (which depends on the permissible minimum pressure of the pressure vessel 110).

[0064] The pressure vessel system 100 is configured to conduct fuel from the pressure vessel 110 via a pressure transducer 120 to an energy converter 102 (e.g., to generate electrical energy for operating an electric drive motor of a motor vehicle). Furthermore, the pressure vessel system 100 includes a low-pressure sensor 122 on the low-pressure side of the pressure transducer 120, between the pressure transducer 120 and the energy converter 102.

[0065] The method 200 includes determining 201 that a measurement operating situation of the pressure vessel system 100 exists. For example, it may be determined that a measurement operating situation exists if it is detected that the pressure transducer 120 is (permanently and / or completely) open and that no fuel is being supplied to the energy converter 102.

[0066] The method 200 further comprises detecting 202, upon (recognized) presence of the measurement operating situation and based on the low-pressure sensor 122, a measured value of the fuel pressure on the low-pressure side of the pressure transducer 120. Furthermore, the method 200 comprises determining 203 the pressure information relating to the fuel pressure in the pressure vessel 110 (in particular the pressure information regarding whether the fuel pressure in the pressure vessel 110 reaches or falls below the minimum pressure threshold) based on the measured value of the low-pressure sensor 122.

[0067] By using one or more measured values ​​of the low-pressure sensor 122, 203 to determine the pressure in the pressure vessel 110, the pressure in the pressure vessel 110 can be determined with a relatively low measurement error, thereby enabling particularly safe operation of a pressure vessel system 100.

[0068] The present invention is not limited to the embodiments shown. In particular, it should be noted that the description and figures are intended only to illustrate the principle of the proposed methods, devices, and systems by way of example. List of reference symbols 100 pressure vessel system 101 (Control) Device 102 energy converters 105 Supply valve 110 pressure vessels 111 Tank and / or shut-off valve 120 pressure transducers 121, 122 pressure sensor 200 methods for determining pressure information 201-203 Procedural steps

Claims

[1] Device (101) for determining pressure information relating to a fuel pressure of fuel in a pressure vessel (110) of a pressure vessel system (100); wherein the pressure vessel system (100) is designed to conduct fuel from the pressure vessel (110) via a pressure transducer (120) to an energy converter (102); and wherein the pressure vessel system (100) has a low-pressure sensor (122) on a low-pressure side of the pressure transducer (120), between the pressure transducer (120) and the energy converter (102); wherein the device (101) is configured, - to determine that a measuring operating situation of the pressure vessel system (100) exists in which - the pressure transducer (120) is open; and - no fuel is supplied to the energy converter (102); - when the measuring operating situation is present, to record a measured value of the fuel pressure on the low-pressure side of the pressure transducer (120) using the low-pressure sensor (122); and - to determine pressure information relating to the fuel pressure in the pressure vessel (110) on the basis of the measured value of the low pressure sensor (122). [2] Device (101) according to claim 1, wherein the device (101) is arranged - to determine that a shut-off valve (111) of the pressure vessel (110) is open; and - in response thereto, in particular only in response thereto, to determine that a measuring operating situation of the pressure vessel system (100) exists. [3] Device (101) according to one of the preceding claims, wherein the device (101) is arranged - to determine, on the basis of the measured value of the low-pressure sensor (122) as pressure information, whether a minimum pressure threshold value for the fuel pressure in the pressure vessel (110) has been reached or fallen below; wherein the minimum pressure threshold value is in particular a safety amount above a permissible minimum pressure of the pressure vessel (110); and - to effect one or more safety measures with respect to the pressure vessel (110) when it is determined that the minimum pressure threshold value for the fuel pressure of fuel in the pressure vessel (110) has been reached or fallen below. [4] Device (101) according to claim 3, wherein the device (101) is arranged - to compare the measured value of the low pressure sensor (122) with the minimum pressure threshold; and - depending on the comparison, in particular when the measured value of the low-pressure sensor (122) is equal to or less than the minimum pressure threshold, to determine that the minimum pressure threshold for the fuel pressure of fuel in the pressure vessel (110) has been reached or fallen below. [5] Device (101) according to one of claims 3 to 4, wherein the one or more security measures comprise - closing a shut-off valve (111) of the pressure vessel (110); - Deactivating the pressure vessel system (100), in particular the energy converter (102); and / or - issuing a notice to a user of the pressure vessel system (100). [6] Device (101) according to one of the preceding claims, wherein - the pressure vessel system (100) has a high-pressure sensor (121) on a high-pressure side of the pressure transducer (120), between the pressure vessel (110) and the pressure transducer (120); and - the device (101) is arranged - to compare a measured value of the high pressure sensor (121) with a pressure threshold value; - to determine the pressure information based on the measured value of the high-pressure sensor (121) if the measured value of the high-pressure sensor (121) is equal to or greater than the pressure threshold value; and - to determine the pressure information on the basis of the measured value of the low pressure sensor (122) if the measured value of the high pressure sensor (121) is less than the pressure threshold value. [7] Device (101) according to claim 6, wherein the device (101) is arranged, when the measured value of the high pressure sensor (121) is less than the pressure threshold value, - to determine whether a measuring operating situation of the pressure vessel system (100) exists in order to be able to determine the pressure information on the basis of the measured value of the low-pressure sensor (122); and - to determine the pressure information based on the measured value of the low pressure sensor (122) when it is determined that a measuring operating situation exists. [8] Device (101) according to one of claims 6 to 7, wherein - the pressure threshold value depends on a measurement error and / or a measurement tolerance of the high-pressure sensor (121); and / or - the pressure threshold value is greater than a minimum pressure of fuel in the pressure vessel (110), which must not be undercut for safety reasons; and / or - the pressure threshold is greater than a minimum pressure threshold used to determine the pressure information based on the measured value of the low-pressure sensor (122); and / or - the pressure threshold value is less than a setpoint for the fuel pressure of fuel on the low pressure side of the pressure transducer (120). [9] Device (101) according to one of the preceding claims, wherein the device (101) is arranged - to detect that - a refueling operation is to be carried out to refuel the pressure vessel (110) with fuel; and / or - the pressure vessel system (100) is to be deactivated; and - in response to the detection, to check whether a measuring operating situation of the pressure vessel system (100) exists or not. [10] Device (101) according to one of the preceding claims, wherein - the pressure vessel system (100) comprises a supply valve (105) arranged between the pressure converter (120) and the energy converter (102); and - the device (101) is designed to check at a check point in time whether the measuring operating situation is present or not, - to determine whether the supply valve (105) is open or closed at the check time; and - to determine that no supply of fuel is made to the energy converter (102) when it is determined that the supply valve (105) is closed. [11] Device (101) according to one of the preceding claims, wherein the device (101) is configured to check at a check time whether the measuring operating situation is present or not, - to compare a measured value of the low-pressure sensor (122) at the check time with a target value of the fuel pressure of fuel on the low-pressure side; and - to determine that the pressure transducer (120) is open when the measured value of the low pressure sensor (122) is less than the setpoint of the fuel pressure of fuel on the low pressure side. [12] Method (200) for determining pressure information relating to a fuel pressure of fuel in a pressure vessel (110) of a pressure vessel system (100); wherein the pressure vessel system (100) is designed to conduct fuel from the pressure vessel (110) via a pressure transducer (120) to an energy converter (102); and wherein the pressure vessel system (100) has a low-pressure sensor (122) on a low-pressure side of the pressure transducer (120), between the pressure transducer (120) and the energy converter (102); wherein the method (200) comprises, - Determining (201) that a measuring operating situation of the pressure vessel system (100) exists in which - the pressure transducer (120) is open; and - no fuel is supplied to the energy converter (102); - detecting (202), when the measuring operating situation is present and using the low-pressure sensor (122), a measured value of the fuel pressure on the low-pressure side of the pressure transducer (120); and - Determining (203) the pressure information relating to the fuel pressure in the pressure vessel (110) on the basis of the measured value of the low-pressure sensor (122).

Images