Tank systems and methods for monitoring their tightness

Abstract

The tank system (100) for supplying a fluid to a consumer (115) comprises at least one tank (101), a system isolation valve (107), and a mechanically controlled pressure controller (111), the system isolation valve (107) being fluidly connected to the pressure controller (111) via a system pipe (113), the at least one tank (101) comprising a tank valve (103), the tank valve (103) being fluidly connected to the system isolation valve (107) via a tank pipe (105), a tank pipe sensor (109) arranged in the tank pipe (105), a system pipe sensor (117) arranged in the system pipe (113), and a calculation unit (119).

Description

[Technical Field]

[0001] The present invention relates to a tank system, a fuel cell system and a method for monitoring the tightness of a tank system as set forth in the accompanying claims. [Background technology]

[0002] Tank systems having high pressure reservoirs, such as those utilized to supply hydrogen to fuel cell systems, typically include a system isolation valve that separates the high pressure region from the medium pressure region of each tank system.

[0003] A mechanical pressure controller is positioned between the system isolation valve and the consumer to regulate the pressure at which fluid is supplied to the consumer from the respective high pressure reservoir.

[0004] To enable the system isolation valves to be used as redundant shutoff valves, monitoring of the tightness of the system isolation valves is required. Summary of the Invention

[0005] The present invention provides a tank system, a fuel cell system, and a method for monitoring the tightness of a tank system. Further features and details of the invention are apparent from the respective dependent claims, the description, and the drawings. The features and details described in the context of the method according to the invention are of course also valid in the context of the tank system according to the invention or the fuel cell system according to the invention, and vice versa, so that the disclosures relating to the individual aspects of the invention are always mutually referred to or can be referred to.

[0006] The presented invention serves, inter alia, to provide a highly reliable tank system.

[0007] Thus, in a first aspect of the present invention, a tank system for supplying fluid to a consumer device is presented.

[0008] The tank system described includes at least one tank, a system isolation valve, and a mechanically controlled pressure controller, the system isolation valve being fluidly connected to the pressure controller via an intermediate pipe, the at least one tank including a tank valve, the tank valve being fluidly connected to the system isolation valve via the tank pipe, and a computing unit.

[0009] The calculation unit is electrically connected to the tank valve and the system isolation valve and is configured to, in a first step, first close the tank valve of at least one tank while fluid is flowing from the tank system to the consumer, and in a second step subsequently close the system isolation valve, so that the tank pressure of the at least one tank becomes higher than the tank piping pressure of the tank piping, and the tank piping pressure becomes higher than the system piping pressure of the system piping, and the pressure controller opens, connecting the intermediate piping of the intermediate region between the system isolation valve and the pressure controller in fluid communication with the supply piping between the pressure controller and the consumer.

[0010] The calculation unit is further configured to estimate a first fluid mass at the first time in the region before the system isolation valve by reference to a first tank piping temperature and pressure of the tank piping determined at the first time, and to estimate a first fluid mass at the first time in the region after the system isolation valve by reference to a system piping temperature and pressure of the system piping determined at the first time.

[0011] The calculation unit is further configured to estimate a second fluid mass at the second time in the area before the system isolation valve by reference to the second tank piping temperature and the pressure in the tank piping determined at the second time, estimate a second fluid mass at the second time in the area after the system isolation valve by reference to the second system piping temperature and the pressure in the system piping determined at the second time, and monitor the tightness of the tank system by reference to a change in the first fluid mass in the area before the system isolation valve relative to the second fluid mass in the area before the system isolation valve and / or by reference to a change in the first fluid mass in the area after the system isolation valve relative to the second fluid mass in the area after the system isolation valve. A computing unit is understood in the context of the presented invention to be a computer, a processor, a sub-processor, a controller or any other programmable circuit.

[0012] The area before the system isolation valve is understood in the context of the presented invention to mean the area arranged before the system isolation valve in the direction of flow of the fluid from the tank, in particular the area between the tank and the system isolation valve. Correspondingly, the area after the system isolation valve is understood in the context of the presented invention to mean the area arranged after the system isolation valve in the direction of flow of the fluid from the tank, in particular the area between the system isolation valve and the consumer.

[0013] A second point in time is understood to be a point in time that is later in time than the first point in time in the context of the presented invention.

[0014] The presented invention is based on a tank system that includes electrically controlled valves, i.e., tank valves for each tank and system isolation valves. Accordingly, one or more tank valves and the system isolation valve can be controlled by a computing unit as envisaged by the present invention. For this purpose, each valve is connected to the computing unit, for example, via a wired interface.

[0015] To monitor the tightness of the tank system presented, the calculation unit executes a process in which, in a first step, the tank valve is first closed while the consumer draws or delivers fluid from the tank system, thereby creating a pressure difference in the tank piping between the tank and the consumer or system isolation valve, since the fluid mass passing through the consumer is removed from the tank piping, reducing the pressure in the tank piping.

[0016] Subsequently, i.e., later in time than the first step, the system isolation valve is closed in a second step, which causes a pressure difference between the area before the system isolation valve and the area after the system isolation valve. This is because the fluid mass passing through the consumer is removed from the area after the system isolation valve, causing a pressure drop in the area after the system isolation valve. Accordingly, after the second step, a state occurs in the tank system where the tank pressure in the tank is higher than the tank pipe pressure in the tank piping, and the tank pipe pressure is higher than the system pipe pressure in the system piping in the area after the system isolation valve, and the pressure controller opens, connecting the intermediate pipe in the intermediate area between the system isolation valve and the pressure controller in fluid communication with the supply pipe between the pressure controller and the consumer. This means that the pressure controller remains open in the second step even after the consumer is shut down or deactivated.

[0017] By carrying out the first and second steps, different pressures are regulated in at least the area before the system isolation valve and the area after the system isolation valve in the tank system, and the areas are isolated from each other. Accordingly, if the system isolation valve is properly closed or sealed, the pressure transition in the area before the system isolation valve can be evaluated independently of the pressure transition in the area after the system isolation valve.

[0018] In order to monitor the tightness of the tank system over time, it is intended that the pressure in the area in front of the system isolation valve is determined at a first time point by a tank piping sensor arranged in the area in front of the system isolation valve, in particular after deactivation of a consumer device, and with reference to this pressure a first fluid mass in the area in front of the system isolation valve at the first time point is estimated, and the first fluid mass in the area in front of the system isolation valve is matched with a second fluid mass in the area in front of the system isolation valve, which is determined by the pressure determined by the tank piping sensor at a second time point.

[0019] The calculation unit may be configured to mathematically relate measurements determined by the tank piping sensors to the temperature of the tank system and to a predetermined volume of the area before the system isolation valve to determine the fluid mass in the area before the system isolation valve, and to mathematically relate measurements determined by the system piping sensors to the temperature of the tank system and to a predetermined volume of the area after the system isolation valve to determine the fluid mass in the area after the system isolation valve.

[0020] To determine the temperature of the tank system, temperature sensors may be used in the tank system, particularly in each tank or around the tank system, and / or a mathematical model of the tank system may be used.

[0021] By matching the first fluid mass in the area in front of the system isolation valve with the second fluid mass in the area in front of the system isolation valve, the change in fluid mass in the area in front of the system isolation valve over time can be estimated, thereby enabling a leak in the area in front of the system isolation valve to be recognized with high confidence, for example, when the second fluid mass in the area in front of the system isolation valve is smaller than the first fluid mass in the area in front of the system isolation valve.

[0022] By matching the second fluid mass in the area after the system isolation valve with the first fluid mass in the area after the system isolation valve, the change in fluid mass in the area after the system isolation valve over time can be estimated, thereby enabling a leak in the area after the system isolation valve to be recognized with high confidence, for example, when the second fluid mass in the area after the system isolation valve is smaller than the first fluid mass in the area after the system isolation valve.

[0023] The calculation unit may be configured to output an error message indicating a leak in the system isolation valve in the case where a decrease in the second fluid mass in the area before the system isolation valve relative to the first fluid mass in the area before the system isolation valve occurs in conjunction with an increase in the second fluid mass in the area after the system isolation valve relative to the first fluid mass in the area after the system isolation valve.

[0024] If the second fluid mass in the area after the system isolation valve increases while the second fluid mass in the area before the system isolation valve decreases at the same time, it can be assumed that fluid is moving in the direction of the pressure gradient from the area before the system isolation valve, through the system isolation valve, to the area after the system isolation valve. Accordingly, it can be inferred that the system isolation valve is not sealing or is defective, and an appropriate error message can be output.

[0025] Furthermore, the calculation unit may be configured to output an error message indicating a leak in the area between the tank valve and the system isolation valve in cases where a decrease in the second fluid mass in the area before the system isolation valve relative to the first fluid mass in the area before the system isolation valve does not occur in conjunction with an increase in the second fluid mass in the area after the system isolation valve relative to the first fluid mass in the area after the system isolation valve.

[0026] Furthermore, the calculation unit may be configured to output an error message indicating a leak in the area upstream of the system isolation valve, in particular in at least one tank valve, in the case where the second fluid mass in the area upstream of the system isolation valve is greater than the first fluid mass in the area upstream of the system isolation valve.

[0027] When a second fluid mass in the area in front of the system isolation valve increases relative to a first fluid mass in the area in front of the system isolation valve, i.e., when the fluid mass in the area in front of the system isolation valve increases over time, particularly in the tank piping, it can be assumed that fluid is flowing from the tank into the area in front of the system isolation valve or into the tank piping, which must be the result of at least one non-sealing tank valve.

[0028] To output the error message, the calculation unit may store the error message, for example in a retrievable manner, in a memory, for example an error memory, and / or may transmit the error message to an indicator, for example a display of a consumer device supplied with fluid by the tank system.

[0029] The calculation unit may further be intended to be configured to output a validation message indicating the tightness of the tank system for cases where the first fluid mass in the area before the system isolation valve is equal to the second fluid mass in the area before the system isolation valve and the first fluid mass in the area after the system isolation valve is equal to the second fluid mass in the area after the system isolation valve.

[0030] For cases where all fluid masses are or remain constant over time, the tank system can be considered leak-free and a validation message can be output.

[0031] The computing unit may further be intended to include an interface for communicating with the consumer device, the computing unit being configured to receive a deactivation command from the consumer device to deactivate the consumer device, or to select a time to close the tank valve in response to a deactivation command, or to receive a time to close the tank valve from the consumer device.

[0032] In order to use the controlled pressure drop in the tank system to adjust different pressure zones in the tank system, the consumer must be in a state in which the fluid is delivered from the tank system but is not hindered in its function by the closure of the tank valve and the system isolation valve. Since such a state occurs upon deactivation of the consumer, the moment of closure of the tank valve can be selected depending on the deactivation command for deactivating the consumer, for example within a predetermined time range after the deactivation command.

[0033] Accordingly, the time at which the system isolation valve closes can also be selected depending on the time at which the tank valve closes and / or depending on the deactivation command, and can correspond to a predetermined time range after the time at which the tank valve closes.

[0034] The calculation unit may further be configured to receive information from the consumer device regarding the expected fluid consumption on the side of the consumer device and, in response to the expected fluid consumption, select a time to close the system isolation valve so that the consumer device reduces the pressure in the area behind the system isolation valve and opens the pressure controller.

[0035] In order to utilize the fluid consumption of the respective consumer to reduce the pressure in the area behind the system isolation valve, it is advisable to avoid a situation in which the system isolation valve is closed and the consumer is unable to extract fluid. Accordingly, the time for closing the system isolation valve can be selected so that the remaining amount that the consumer still extracts before deactivation of the fluid extraction corresponds to the fluid mass in the area behind the system isolation valve and before the consumer.

[0036] It may further be intended that the tank system is a hydrogen pressure tank system, with at least one tank being a hydrogen pressure tank.

[0037] It may further be intended that the calculation unit is configured for determining a tank pipe temperature of the tank pipe by means of a tank pipe temperature sensor and / or by means of a mathematical model for determining the tank pipe temperature, and / or for determining a system pipe temperature of the system pipe by means of a system pipe temperature sensor and / or by means of a mathematical model for determining the system pipe temperature.

[0038] In a second aspect, the presented invention relates to a fuel cell system.

[0039] The fuel cell system presented comprises a possible embodiment of the tank system presented, in which a controller of the fuel cell system is communicatively connected with a computing unit of the tank system.

[0040] In particular, the calculation unit of the tank system may be configured to output error messages and / or validation messages on a display of the fuel cell system.

[0041] In a third aspect, the presented invention relates to a method for monitoring the tightness of a tank system.

[0042] The method presented includes closing a tank valve of at least one tank of the tank system while fluid is flowing from the tank system to a consumer; closing a system isolation valve after the tank valve is closed, thereby causing a tank pressure in the at least one tank to be higher than a tank piping pressure in the tank piping between the at least one tank and the system isolation valve, which tank piping pressure is higher than a system piping pressure in the system piping in an area after the system isolation valve; opening a pressure controller between the system isolation valve and the consumer to connect an intermediate piping in an intermediate area between the system isolation valve and the pressure controller in fluid communication with a supply piping between the pressure controller and the consumer; determining a first fluid mass at a first time point in the area before the system isolation valve with reference to a first upstream temperature determined at the first time point for the area before the system isolation valve; and determining a second fluid mass at a second time point in the area before the system isolation valve with reference to a second upstream temperature determined at the second time point for the area before the system isolation valve. a first fluid mass in the area after the system isolation valve at a first time point is determined with reference to a first later-stage temperature determined for the area after the system isolation valve at the first time point; a second fluid mass in the area after the system isolation valve at a second time point is determined with reference to a second later-stage temperature determined for the area after the system isolation valve at the second time point; and monitoring the tightness of the tank system with reference to a change in the first fluid mass in the area before the system isolation valve relative to the second fluid mass in the area before the system isolation valve and / or with reference to a change in the first fluid mass in the area after the system isolation valve relative to the second fluid mass in the area after the system isolation valve. Other advantages, features, and details of the present invention will become apparent from the following detailed description of the preferred embodiments of the present invention, which is given with reference to the accompanying drawings. Each feature mentioned in the claims and the detailed description of the invention may be an essential part of the invention either alone or in any combination. [Brief explanation of the drawings]

[0043] [Figure 1] FIG. 1 is a schematic diagram illustrating one possible embodiment of the tank system presented. [Figure 2] 1 is a schematic diagram illustrating one possible embodiment of the fuel cell system presented. [Figure 3] FIG. 1 illustrates one possible embodiment of the method presented. DETAILED DESCRIPTION OF THE INVENTION

[0044] 1 shows a tank system 100. The tank system 100 includes multiple tanks 101, each of which includes a tank valve 103.

[0045] Tank piping 105 connects tank 101 and / or tank valve 103 in fluid communication with system isolation valve 107 .

[0046] Located in the tank pipe 105 is a tank pipe sensor 109 configured to detect pressure and optionally also temperature in the tank pipe 105 .

[0047] Accordingly, the tank 101 , tank valve 103 , tank piping 105 , and tank piping sensor 109 form the area before the system isolation valve 107 .

[0048] In the area after the system isolation valve 107 is located a pressure controller 111 which regulates the pressure in the system piping 113 for supply to the consumer 115 .

[0049] A system piping sensor 117 is located that is configured to also detect

[0050] The tank system 100 further includes a calculation unit 119 configured to first close the tank valve 103 in a first step while fluid is flowing from the tank system 100 to the consumer 115, and subsequently close the system isolation valve 107 in a second step, so that the tank pressure in each tank 101 becomes higher than the tank piping pressure in the tank piping 105, and the tank piping pressure becomes higher than the system piping pressure in the system piping 113, and the pressure controller 111 opens to fluidly connect the intermediate piping 121 in the intermediate region between the system isolation valve 107 and the pressure controller 111 to the supply piping 123 between the pressure controller 111 and the consumer 115.

[0051] The calculation unit 119 further includes a calculation unit for estimating a first fluid mass at a first time point in an area before the system isolation valve 107 with reference to measurements determined at a first time point by the tank piping sensor 109, for estimating a first fluid mass at a first time point in an area after the system isolation valve 107 with reference to measurements determined at a first time point by the system piping sensor 117, for estimating a second fluid mass at a second time point in an area before the system isolation valve 107 with reference to measurements determined at a second time point by the tank piping sensor 109, and for estimating a second fluid mass at a second time point in an area after the system isolation valve 107 with reference to measurements determined at a second time point by the tank piping sensor 109. and to estimate a second fluid mass in the area after the system isolation valve 107 at a second time point by reference to measurements determined by the system piping sensor 117 at a second time point, and to monitor the tightness of the tank system 100 by reference to a change in the first fluid mass in the area before the system isolation valve 107 relative to the second fluid mass in the area before the system isolation valve 107 and / or by reference to a change in the first fluid mass in the area after the system isolation valve 107 relative to the second fluid mass in the area after the system isolation valve 107.

[0052] Optionally, temperature sensors 125 are arranged in the tanks 101 in order to detect the temperature of the fluid, i.e. in particular hydrogen, stored in each tank 101 and to calculate the fluid mass occurring in the area before and / or after the system isolation valve 107. To this end, for example, the values ​​determined by the temperature sensors 125 can be fed into a mathematical model of the tank system 100.

[0053] 2 shows a fuel cell system 200. The fuel cell system 200 includes the tank system 100 shown in FIG.

[0054] FIG. 3 illustrates a method 300 for monitoring the sealability of a tank system.

[0055] The method 300 includes a first closing step 301 in which a tank valve of at least one tank of the tank system is closed while fluid is flowing from the tank system to the consumer, and a second closing step 303 in which after the tank valve is closed, the system isolation valve is closed, so that the tank pressure of the at least one tank becomes higher than the tank piping pressure of the tank piping between the at least one tank and the system isolation valve, and the tank piping pressure becomes higher than the system piping pressure of the system piping in the area after the system isolation valve, and a pressure controller between the system isolation valve and the consumer opens to fluidly connect the intermediate piping in the intermediate area between the system isolation valve and the pressure controller to the supply piping between the pressure controller and the consumer.

[0056] The method 300 further includes a first determining step 305 in which a first fluid mass at a first time in the area before the system isolation valve is determined with reference to measurements determined at the first time by a tank piping sensor located in the area before the system isolation valve and the pressure in the area before the system isolation valve; a second determining step 307 in which a second fluid mass at a second time in the area before the system isolation valve is determined with reference to measurements determined at the second time by the tank piping sensor and the pressure in the area before the system isolation valve; and a second determining step 308 in which the first fluid mass at a first time in the area after the system isolation valve is determined with reference to measurements determined at the second time by the tank piping sensor and the pressure in the area before the system isolation valve. a third determining step 309 in which a second fluid mass in the area after the system isolation valve is determined with reference to the pressure in the area after the system isolation valve at a first time point; a fourth determining step 311 in which a second fluid mass in the area after the system isolation valve at a second time point is determined with reference to measurements determined by the system piping sensors at the second time point and the pressure in the area after the system isolation valve; and a monitoring step 313 in which the tightness of the tank system is monitored with reference to a change in the first fluid mass in the area before the system isolation valve relative to the second fluid mass in the area before the system isolation valve and / or a change in the first fluid mass in the area after the system isolation valve relative to the second fluid mass in the area after the system isolation valve.

[0057] In particular, the third decision step 309 is performed in parallel with or immediately after the first decision step 305 .

[0058] In particular, the fourth decision step 311 is performed in parallel with or immediately after the second decision step 307 . [Explanation of symbols]

[0059] 100 Tank System 101 Tank 103 Tank valve 105 Tank piping 107 System isolation valve 109 Tank piping sensor 111 Pressure Controller 113 System Piping 115 Consumers 119 Computational Units 121 Intermediate piping 200 Fuel Cell System 201 Control device 300 ways 301 Closed 303 Closed 305 Decision 307 Decision 309 Decision 311 decision 313 Surveillance

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