DE10335245A1 - Cryogenic tank system for storing fuel at a very cold temperature for use in motor vehicles, comprises a gas-tight test layer which is formed between its internal space and the insulating layer - Google Patents

Abstract

The cryogenic tank system (10) comprises a gas-tight test layer (24) which is formed between its internal space (12) and the insulating layer (14). A test mechanism (36) is provided for monitoring the pressure inside the test layer. The test layer (24) is formed of two membranes (26,28), at least one of which is supported on the support structure (16) of the internal space for containing the fuel. An independent claim is also included for the application of the cryogenic tank system in a motor vehicle.

Description

The The invention relates to a cryotank system for storing fuel in Tiefkaltem state, in particular a cryogenic tank for storing of liquefied Hydrogen for a motor vehicle drive unit, wherein the cryotank with a Interior for picking up the liquefied fuel and a Provided surrounding the interior insulation layer. Further The invention relates to the use of such a cryotank system in a motor vehicle.

In recently, Time will be for Combustion units, such as stationary or mobile Fuel cells or internal combustion engines, amplified alternative drive energies sought and doing it also with liquefied gases in general and with liquid Hydrogen worked in particular. The liquefied gas or the liquid hydrogen is in Kryotank systems of the type mentioned in Tiefkaltem state stored, because below room temperature such fuels would otherwise the gaseous Assume state and thus require a disproportionate memory space.

To the Store the fuel in cryogenic state are the cryotank systems with a liquid Fuel receiving interior and a surrounding this interior Insulation layer provided. The interior is usually of an inner container and the insulation layer surrounded by an outer container. Fluid conducting elements, such as pipes with valves and also heat exchangers, are passed through the insulating layer and connect the interior with the combustion unit to be supplied.

at such a cryogenic tank system can cause problems if, for example, a leak in the interior or a line break on Tank due to an unavoidable heat input from the environment liquid Fuel evaporates on the tank. Although evaporating fuel could in principle be thermally disposed of with a burner, in case of a leak or Line break could the vaporizing amount of fuel but being so big that thermal disposal alone would not be enough.

Especially is serious in these problem cases that a leak or a failure of the cryotank system without any warning or Malfunction even with proper maintenance and even without Incorrect operation could occur.

task The invention is a cryotank system of the aforementioned To provide kind of, in a cost effective and reliable way a problem described above detected and, where appropriate, countermeasures can be initiated.

The Object is according to the invention with a generic Kryotank system solved, in which between the interior and the insulation layer is a gas-tight completed test layer trained and a testing device to monitor the pressure within the test layer is provided.

According to the invention is at a cryotank system of the fuel receiving interior with a double-walled shell in the form of a limited to certain areas or the interior Completely enveloping, gastight test layer Mistake. With the test layer is for example an inner container, which surrounds the interior, in addition secured and monitored.

The provided according to the invention gastight test layer forms a hermetically sealed space between the interior and the surrounding insulation layer, such as a leak on the inner container of the cryotank system to a pressure change at the test layer leads and this pressure change according to the invention with a test equipment can be detected and reacted accordingly.

Furthermore forms the inventively provided gas-tight test layer one another shell around the interior of the cryogenic tank system, whereby through this additional shell itself in case of a leak in the inner container the cryotank system leakage of stored in the interior Fuel first is at least largely prevented.

The Invention is further with a cryotank system mentioned above solved, in which around the insulating layer around a second also locally limited or completely enclosing, gastight test layer trained and a second test device to monitor the pressure is provided within the second test layer.

The such trained second test layer according to the invention again forms a double-walled shell, this shell around the Isolation layer is formed around, there detecting a pressure change allows and at the same time an additional one Protection against leakage of fuel from the cryotank system offers.

at a particularly appropriate training The invention is both of a cryotank system mentioned above a first gas-tight test layer between the interior and the insulating layer as well as a second gastight sealed Check Layer provided around the insulation layer around. In the corresponding cryogenic tank system also pressure differences between the test layers are detected, so For example, detects a leak on the insulation layer and can be reacted accordingly. Furthermore, through the two test layers the interior of the cryotank system according to the invention by a total of four more cases (two per test layer) additionally and redundantly sealed.

at An advantageous development of the invention is the first test layer by means of two thin-walled Membranes formed, of which at least one in particular a support structure the interior is supported for receiving fuel. The test layer according to the invention can alone through thin-walled Membranes be formed or sealed, because at the boundary layer of the interior or on the inner container always from the internal overpressure (Tank pressure) or assumed in the event of damage from the depressurized state can be. The membranes can therefore saving weight comparatively thin and without pronounced structural rigidity be educated. The overpressure in the interior can be conventional Way at a support structure of the inner container be included, the first test layer with its two membranes, for example against the inside of this support structure depressed and held there. The pressure in such arranged first Check Layer is normally equal to the internal pressure (tank pressure) of the interior of the cryotank system according to the invention.

In similar Way, it is particularly advantageous if the second invention Test layer by means of two thin-walled Membranes is formed, of which at least one in particular on a support structure the insulating layer is supported. The second test layer surrounding the insulation layer can be solely by means of thin-walled Be sealed membranes because for this second test layer either from the external overpressure (Air pressure) or in the event of damage from a depressurized state can be.

The according to the invention first and / or second test layer should be with at least one for the pressure measurement suitable test gas filled be. Alternatively or in addition could at least one test gas in a test layer be introduced in the event of a leak in the interior or on the insulating layer with an incoming or outgoing gas (for example Air or hydrogen) reacts chemically or physically and in which this reaction is used to detect the leak with a test device (e.g., measuring the electrical conductivity of the test gas). In certain circumstances can when using such, chemically or physically Reactive test gas to a surveillance the pressure at the associated Test layer omitted become. For testing or monitoring the Cryotank system could So alone the optionally occurring reaction of the test gas can be used. Furthermore, could at least one of the test layers according to the invention with at least one gas detector as testing device Be provided with the entry of a gas into the test layer can be determined in it. For example, the gas detector could do this be formed so that it is an entry of air (in particular of Oxygen or nitrogen) or hydrogen into one of the test layers detects (oxygen sensor, nitrogen sensor or hydrogen sensor). The detection of the incoming gas could also alternatively or additionally to a pressure measurement on the associated test layer done.

The Cryotank system according to the invention should about that Be advantageous coupled with a safety device, the at a significant change the pressure in at least one of the test layers or at another test signal automatic at least one security measure initiates. The security measure For example, in a warning of the driver of a vehicle, in a stoppage of the vehicle or in an alarm of emergency services consist.

As mentioned in the beginning it is common in cryotank systems, that they have a line for supplying and discharging fuel to / from Have interior through the insulation layer. In the cryotank system according to the invention Such a line is advantageous from the first test layer essentially surrounded. With the test layer arranged in this way Even a leak in the area of the line can be reliably detected.

Furthermore or alternatively it is advantageous, albeit a valve for throttling and / or shutting off a supply and discharge of fuel to / from Interior, which is also common in cryogenic tank systems, surrounded by the first test layer is. With the help of the first test layer then the valve is secured.

The Secured according to the invention Insulation layer is particularly advantageous as isolation vacuum educated. The isolation vacuum represents a particularly low heat input safe in the cryogenic tank and at the same time very easy due to the according to the invention with membranes monitored test layers become.

The inventive cryotank system is intended in particular for use in a motor vehicle and suitable, because the test layers according to the invention almost require no additional Space, have a low weight and are easy in the control and monitoring well-known mobile cryogenic tank systems.

following become preferred embodiments a cryotank system according to the invention with the attached schematic drawings closer explained. It shows:

1 3 is a sectional perspective view of a first embodiment of a cryotank system according to the invention;

2 , a section of the cryotank system according to 1 in the filled, proper condition,

3 the view according to 2 with a leak on a pipe and on a valve of the cryotank system,

4 the view according to 2 with a leak on an outer shell of the cryotank system,

5 the view according to 2 with a leak on an inner shell of the cryotank system,

6 the view according to 2 with a leak on a first membrane of a second test layer of the cryotank system,

7 the view according to 2 with a leak between a first test layer and the second test layer of the cryotank system,

8th the view according to 2 A second embodiment of a cryotank system according to the invention and

9 a highly simplified sectional view of a third embodiment of a cryotank system according to the invention.

In 1 is a cryogenic tank system 10 for storing cryogenic hydrogen in the liquid state. The hydrogen is in a substantially cylindrical interior 12 of the cryotank system 10 saved. To the interior 12 of the cryotank system 10 around is an insulation layer 14 formed, the heat input from an environment of the cryotank system 10 should avoid as possible in the liquid hydrogen.

The interior 12 is from an inner shell or an inner container 16 limited to the outside of the insulation layer 14 borders. To the insulation layer 14 around is an outer shell or an outer container 18 formed, which is the actual outer casing of the cryotank system 10 forms.

A line 20 with a valve disposed therein 22 leads from the interior 12 out to a combustion unit, not shown. In the combustion unit, the interior can 12 stored hydrogen are burned and converted into electrical and mechanical energy, for example, to drive a motor vehicle.

To ensure that the interior 12 stored hydrogen does not inadvertently enter the environment of the cryotank system 10 can enter is the interior 12 with a first test layer or a first layered test volume 24 surrounded by a first membrane 26 and a second membrane 28 is limited. The first membrane 26 is a thin layer of a comparatively flexible material that extends between the interior 12 and the first test layer 24 located. The second membrane 28 is also formed comparatively thin-walled and lies on the inside of the inner shell 16 at.

As a further safety device of the cryotank system 10 is a second test layer 30 provided as a thin layer or layered test volume, the insulating layer 14 essentially surrounds. The second test layer 30 is inside of a first membrane 32 limited, which is also relatively thin-walled and between the insulation layer 14 and the second test layer 30 located. Furthermore, the second test layer 30 on the outside of a second thin-walled membrane 34 bounded on the inside of the outer shell 18 is applied.

With the first test layer 24 is fluid-conducting a first test device 36 connected with the pressure in the first test layer 24 can be determined. Similarly, with the second test layer 30 a second testing device 38 fluidly connected. The testing equipment 36 and 38 are set up to be in the first test 24 or in the second test layer 30 indicate present pressure p ₁ or p ₂ and can initiate at least one safety measure in cooperation with a safety device, not shown, at a significant change of at least one of the two pressures automatically.

Such safety measures can for example in the shutdown of an associated vehicle or in the alert of Einsatzkräf exist.

In 2 is the cryotank system 10 illustrated in a proper condition in which the interior 12 of the cryotank system 10 with cryogenic, liquefied hydrogen at a hydrogen pressure p _h and the insulation layer 14 are filled with an isolation vacuum at a vacuum pressure p _v . In the environment of the cryotank system according to 2 is the ambient pressure p _u before.

In proper condition, all membranes 26 . 28 . 32 and 34 the first test layer 24 and the second test layer 30 intact and within the first test layer 24 is a test pressure p ₁ <p ₂ and in the second test layer 30 a test pressure p ₂ <p _u measured.

In 3 is the cryotank system 10 illustrated with a first damage when connected to the line 20 a leak 40 and at the valve 22 a leak 42 available. In such a damage to the cryotank system 10 changes due to one of the leaks 40 respectively. 42 the test pressure p ₁ in the first test layer 24 , The test pressure p ₁ assumes the hydrogen pressure p _h , while the test pressure p ₂ in the second test layer 30 continues to be less than the ambient pressure. The pressure change of the test pressure p ₁ is from the first test device 36 and the associated safety device detected and the necessary security measures are initiated.

In 4 is a claim on the cryotank system 10 shown in which on the outer shell 18 a leak 44 is present. Due to the leak 44 is in the cryogenic tank system 10 according to 4 also the second membrane 34 the second test layer 30 damaged. Therefore, the pressure p ₂ in the second test layer changes 38 ; p ₂ is equal to the ambient pressure p _u . This pressure change is from the second test device 38 detected and appropriate security measures are taken.

5 is an illustration of a cryotank system 10 with a damage or a leak 46 on the inner shell 16 , the leak 46 leads to damage of the second membrane 28 the first test layer 24 so that the test pressure p ₁ assumes the vacuum pressure p _v . On this pressure change can with the help of the first test device 36 be adequately responded.

In 6 is a cryogenic tank system 10 illustrates that there is a leak 48 at the first membrane 32 the second test layer 30 has come. the leak 48 at the first membrane 32 leads to a pressure equalization between the insulation layer 14 and the second test layer 30 , The test pressure p ₂ is therefore equal to the vacuum pressure p _v . On the pressure change can with the help of the second test device 38 be reacted.

7 finally serves to illustrate a cryotank system 10 in which there is a leak 50 between the first test layer 24 and the second test layer 30 has come. The first test layer 24 and the second test layer 30 border directly in the area where the line 20 with her valve 22 through the second test layer 30 passed through, because in the cryogenic tank system 10 is also the lead 20 with her valve 22 from the first test layer 24 surround.

the leak 50 leads to a pressure equalization between the first and the second test layer 24 respectively. 30 , so that the two test pressures p ₁ and p ₂ equalize. This pressure change also deviates from the in 2 illustrated pressure situation in a proper state of the cryotank system 10 from. The pressure change can therefore with the aid of the first and second test device 36 respectively. 38 detected and it can be reacted accordingly with a security measure.

In 8th is an embodiment of a cryotank system 10 illustrated in which as in the embodiment according to the 1 to 7 a first test layer 24 and a second test layer 30 are provided. So with the cryotank system 10 reliably prevents that at an interface between the first test layer 24 and the environment by a leak of air below ambient temperature to the wall of the inner container 16 is a third test layer 52 provided that the exit of the pipe 20 with their first test layer 24 from the outer container 18 on the outside and the first test device 36 covered.

The third test layer 52 is either evacuated or filled with a test gas pressure that is different than the pressures in the adjacent areas. A leak at the interface between the first test layer 24 and the environment may therefore due to a resulting pressure change in the test layer 52 be determined.

With 9 should again be emphasized that the test layers of the invention 24 . 38 and 52 may not completely enclose the associated spaces Under certain circumstances, it may be sufficient for the test beds to be limited to specific locations, sections or areas of the associated spaces.

In 9 is, for example, a first test layer 24 shown only in the area of entry of the pipe 20 is formed in the cryogenic tank system. With the reference numerals 54 . 56 . 58 . 60 . 62 and 64 are other sections of a cryotank system 10 illustrates where further locally limited further test layers 24 . 30 and or 52 make sense. Particularly to be protected steles include in particular those areas of the inner and outer containers 16 respectively. 18 that have a small radius of curvature.

10

Cryogenic tank system

12

inner space

14

insulation layer

16

inner shell or inner container

18

outer shell or outer container

20

management

22

Valve

24

first Check Layer

26

first Membrane of the first test layer

28

second Membrane of the first test layer

30

second Check Layer

32

first Membrane of the second test layer

34

second Membrane of the second test layer

36

first test equipment

38

second test equipment

40

leak on the line

42

leak at the valve

44

leak on the outer shell

46

leak on the inner shell

48

leak at the first membrane of the second test layer

50

leak between the first test layer and the second test layer

52

third Check Layer

54 to 62

areas further locally limited test layers

Claims (12)

Cryogenic tank system ( 10 ) for storing fuel in a cryogenic state with an interior space ( 12 ) for receiving the fuel and the interior ( 12 ) surrounding insulation layer ( 14 ), characterized in that between the interior ( 12 ) and the insulation layer ( 14 ) a gas-tight test layer ( 24 ) and a test device ( 36 ) for monitoring the pressure within the test layer ( 24 ) is provided. Cryogenic tank system according to claim 1, characterized in that the first test layer ( 24 ) by means of two membranes ( 26 . 28 ) is formed, of which at least one in particular on a support structure ( 16 ) of the interior ( 12 ) is supported for receiving fuel. Cryogenic tank system ( 10 ) for storing fuel in a cryogenic state with an interior space ( 12 ) for receiving the fuel and the interior ( 12 ) surrounding insulation layer ( 14 ), in particular according to claim 1 or 2, characterized in that around the insulating layer ( 14 ) around a second gas-tight test layer ( 30 ) and a second test device ( 38 ) for monitoring the pressure within the second test layer ( 30 ) is provided. Cryogenic tank system according to claim 3, characterized in that the second test layer ( 30 ) by means of two membranes ( 32 . 34 ) is formed, of which at least one in particular on a support structure ( 18 ) of the insulation layer ( 14 ) is supported. Cryogenic tank system according to one of claims 1 to 4, characterized in that the first and / or second test layer ( 24 ; 30 ) is filled with at least one test gas. Cryotank system according to one of claims 1 to 5, characterized in that the first and / or second test device ( 36 ; 38 ) with a safety device for the automatic initiation of at least one safety measure in the event of a significant change in the pressure in at least one of the test layers ( 24 ; 30 ) is provided. Cryogenic tank system according to one of claims 1 to 6, characterized in that a line ( 20 ) for supplying and discharging fuel to / from the interior ( 12 ) through the insulation layer ( 14 ) and the first test layer ( 24 ) The administration ( 20 ) through the insulation layer ( 14 ) substantially surrounds. Cryogenic tank system according to one of claims 1 to 7, characterized in that a valve ( 22 ) for throttling and / or shutting off a supply and discharge of fuel to / from the interior ( 12 ) and the first test layer ( 24 ) the valve ( 22 ) substantially surrounds. Kroytank system according to one of claims 1 to 8, characterized in that the insulating layer ( 14 ) is designed as isolation vacuum. Cryogenic tank system ( 10 ) according to one of claims 1 to 9, characterized in that the first test layer ( 24 ) around a third gas-tight test layer ( 52 ) and a third test device for monitoring the pressure within the third test layer ( 52 ) is provided. Cryogenic tank system according to claim 10, characterized in that from the third test layer ( 52 ) also the second test facility ( 38 ) is enclosed. Use of a cryotank system according to one of claims 1 to 11 in a motor vehicle convincing.