Pressure Vessel and Motor Vehicle

Abstract

A pressure vessel, in particular a cryogenic pressure vessel, has an inner vessel, an outer vessel and a chamber that can be evacuated at least partly. A motor vehicle includes such a pressure vessel.

Claims

1.-39. (canceled)

40. A cryogenic pressure vessel for storing fuel in a motor vehicle, comprising: an inner vessel; and an outer vessel, wherein an evacuated space is arranged at least in certain regions between the inner vessel and the outer vessel.

41. The pressure vessel according to claim 40, wherein the inner vessel has a plastics material layer, a barrier layer is arranged at least in certain regions between the plastics material layer and the evacuated space, the barrier layer is configured and arranged so as to at least reduce passage of constituents escaping from the plastics material layer into the evacuated space, and a gap is formed at least in certain regions between the barrier layer and the plastics material layer.

42. The pressure vessel according to claim 41, wherein the barrier layer comprises a length compensation device which is configured to compensate changes in length of the inner vessel.

43. The pressure vessel according to claim 42, wherein the length compensation device comprises at least one corrugated bellows element.

44. The pressure vessel according to claim 42, wherein the length compensation device is arranged directly adjacent to that end of the inner vessel which is configured as a floating bearing.

45. The pressure vessel according to claim 41, wherein the barrier layer is of a metal material.

46. The pressure vessel according to claim 41, wherein the plastics material layer is a fiber-reinforced layer that surrounds a liner, and the barrier layer separates the fiber-reinforced layer from the evacuated space in substantially gas-tight fashion.

47. The pressure vessel according to claim 41, wherein the inner vessel has a connecting end piece, and a liner and/or a fiber-reinforced layer are/is connected to the connecting end piece.

48. The pressure vessel according to claim 47, wherein the connecting end piece is connected cohesively and in substantially gas-tight fashion to the barrier layer.

49. The pressure vessel according to claim 47, wherein the barrier layer comprises an annular plate that extends radially outward from the connecting end piece.

50. The pressure vessel according to claim 49, wherein a length compensation device is provided at an outer edge of the annular plate, and the annular plate and/or the length compensation device is arranged so as to be set back in an axial direction in relation to an outer delimitation of the connecting end piece.

51. The pressure vessel according to claim 41, wherein a substantially gas-tight space is formed between the barrier layer and the plastics material layer, and the pressure vessel is configured such that a gas composition in the substantially gas-tight space is evaluable from outside the present vessel.

52. The pressure vessel according to claim 51, wherein the substantially gas-tight space comprises at least one test connection, and the test connection is led out of the outer vessel.

53. The pressure vessel according to claim 41, wherein at least one radiation insulator is arranged outside the barrier layer.

54. The pressure vessel according to claim 40, wherein at least one electrical heating element for warming the fuel is provided in the inner vessel.

55. The pressure vessel according to claim 54, wherein the heating element, when installed, runs parallel to or along a longitudinal axis of the inner vessel.

56. The pressure vessel according to claim 54, wherein the heating element projects from an internally situated face side of a connecting end piece of the inner vessel.

57. The pressure vessel according to claim 56, wherein the internally situated face side is spaced apart from a fiber-reinforced layer such that heat generated by the heating element cannot warm the fiber-reinforced layer to a temperature above a limit temperature beyond which damage to the fiber-reinforced layer is likely.

58. The pressure vessel according to claim 54, wherein the heating element is surrounded at least in certain regions by a metal sleeve.

59. The pressure vessel according to claim 58, wherein the metal sleeve is connected in fuel-tight fashion to a connecting end piece of the inner vessel.

60. The pressure vessel according to claim 54, wherein the heating element is provided at a first end of the inner vessel, which is situated opposite a second end at which a line for filling and/or extraction is provided.

61. The pressure vessel according to claim 54, wherein the inner vessel is mechanically coupled to the outer vessel by way of at least one connecting element, and electrical lines of the heating element are routed within the connecting element.

62. The pressure vessel according to claim 61, wherein the connecting element is at least partially of a fiber composite material.

63. The pressure vessel according to claim 54, wherein a ratio of a heating length, projecting into the inner vessel, of the heating element to a total length of the inner vessel is between 0.1 and 0.8 or between 0.25 to 0.5.

64. The pressure vessel according to claim 40, further comprising: a pressure relief device for relieving the pressure vessel of pressure, wherein the pressure relief device has at least one thermally activatable pressure relief apparatus, and the pressure relief apparatus is directly fluidically connected to an internal volume of the pressure vessel via a pressure relief line.

65. The pressure vessel according to claim 64, furthermore comprising: at least one rupture element, wherein the pressure relief apparatus and the rupture element are directly fluidically connected to the internal volume of the pressure vessel.

66. The pressure vessel according to claim 65, further comprising: at least one overpressure discharge valve, wherein at least one fuel converter is provided downstream of the overpressure discharge valve, and the pressure relief apparatus and the overpressure discharge valve are directly fluidically connected to the internal volume of the pressure vessel.

67. The pressure vessel according to claim 66, wherein the pressure relief device comprises an overpressure safety valve, wherein the overpressure safety valve is directly fluidically connected to the internal volume of the pressure vessel.

68. The pressure vessel according to claim 67, wherein the overpressure safety valve is provided so as to be spaced apart from the rupture element.

69. The pressure vessel according to claim 67, wherein the overpressure safety valve is provided at a side of the pressure vessel which is situated opposite the side at which the rupture element is formed.

70. The pressure vessel according to claim 67, wherein the rupture element is provided at a first end, and the overpressure safety valve is provided at a second end that is situated opposite the first end.

71. The pressure vessel according to claim 65, wherein the inner vessel forms the internal volume that stores the fuel.

72. The pressure vessel according to claim 71, wherein the rupture element is provided outside the outer vessel.

73. The pressure vessel according to claim 72, wherein in the wall of the outer vessel, a further rupture element fluidically connected to the evacuated space is provided.

74. The pressure vessel according to claim 66, wherein a pressure relief line has a first line end, and the rupture element and/or an overpressure discharge valve is formed at the first line end.

75. The pressure vessel according to claim 41, wherein a pressure relief line extends over a shell region of the outer vessel.

76. The pressure vessel according to claim 66, wherein a triggering pressure of the overpressure discharge valve is below a triggering pressure of the overpressure safety valve and/or below a triggering pressure of the rupture element.

77. A motor vehicle comprising at least one pressure vessel according claim 67.

78. The motor vehicle according to claim 77, wherein the overpressure safety valve is fluidically connected to a fuel outlet provided at a vehicle roof.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0070] FIG. 1 is a schematic cross-sectional view of the pressure vessel disclosed here; and

[0071] FIG. 2 is a further schematic detail view of the pressure vessel disclosed here.

DETAILED DESCRIPTION OF THE DRAWINGS

[0072] FIG. 1 schematically shows a view of the pressure vessel system disclosed here. The pressure vessel comprises an inner vessel 100 that is surrounded by the outer vessel 200. The evacuated space V is situated between the inner vessel 100 and the outer vessel 200. The inner vessel 100 comprises a liner 110 that is surrounded by a fiber-reinforced layer 120. Here, the filling and extraction line 410 is provided at the second end P2. It would likewise also be possible for two separate lines for filling and extraction to be provided. For filling, the pressure vessel in this case comprises a cryogenic filling connection 432, which is fluidically connected to the tank shut-off valve 420, which in this case is operated at cryogenic temperatures. The fluidic connection between the tank shut-off valve 420 and the cryogenic filling connection 432 is equipped with thermal insulation 433, for example a partially evacuated space and/or insulation with foamed plastics and/or aerogels. The cryogenic filling connection 432 is couplable to a corresponding refueling station coupling.

[0073] It is additionally preferably possible for a further filling connection 434 for warm refueling to be provided. The two filling connections 432, 434 are expediently configured such that the cryogenic filling connection 432 can receive cryogenic fuel at a fuel temperature which is lower, by at least 150 K or at least 180 K, than the lowest fuel temperature that the further filling connection 434 can receive. A pressure line 435 may advantageously be connected to the further filling connection 434, which pressure line, in the evacuated space V, opens into the cryogenic line system, in particular upstream of the tank shut-off valve 420 that is operated under cryogenic conditions, wherein a further tank shut-off valve 437 and/or a pressure-limiting valve 436 is preferably provided in said pressure line 435. The refueling of the pressure vessel can be reliably prevented by means of the further tank shut-off valve 437. The pressure limiting valve 436 may be configured to limit the maximum refueling pressure, preferably to the maximum admissible pressure of the pressure vessel that is allowable during the operation of the pressure vessel (generally the maximum operating pressure).

[0074] In a flow path that is fluidically parallel with respect to the cryogenic tank shut-off valve 420, there is provided a refueling check valve 421 that is configured to allow fuel to pass through to the pressure vessel during the refueling process, and to block the passage in all other operating states (for example extraction or storage). Here, check valves 439 are furthermore provided at the filling connections 432, 434, which check valves prevent a backflow of the fuel into the refueling station or into the surroundings.

[0075] The sensor arrangement provided at the second end P2 comprises in this case a sensor element 205 that is configured to detect a signal that is indicative of at least the fuel temperature in the internal volume I. The sensor element 205 is connected to the sensor connection 204 via the electrical line 203. The sensor connection 204 is in this case provided on the outer vessel 200, and the sensor element 205 is provided on the inner vessel 100. Via the sensor connection 204, a control unit can be connectable or connected to the sensor element 205 via suitable elements such as electrical lines, bus systems etc. The sensor connection 204 and the sensor element 205 are accommodated within the connecting element 144. The connecting element 144 at the second end P2 is expediently constructed as disclosed in conjunction with the connecting element 144 of the first end P1. The sensor connection 204 and the sensor element 205 are in this case arranged coaxially with respect to one another and are preferably configured so as to be coaxial with the pressure vessel longitudinal axis A-A. The sensor element 205, the sensor connection and the electrical line 203 could alternatively or additionally (also) be provided at the first end P1 in the same way.

[0076] In this case, the heating element 130 is arranged at the first end P1, which is situated opposite the second end P2. The heating element 130 is in this case configured as a heating rod that extends concentrically with respect to the pressure vessel longitudinal axis A-A. The heating element 130 is a resistance heating unit. The heating element 130 comprises a metal sleeve 135 which forms the outer surface of the heating element 130 and which thus shields the heating element with respect to the fuel. The heating element 130 is in this case welded in fuel-tight fashion to an internally situated face side 142 of the connecting end piece 140 and projects into the internal volume I of the inner vessel 100. The face side 142 together with the peripheral wall 143 forms the pot-shaped connecting end piece 140.

[0077] The connecting end piece 140 - also referred to as boss - comprises a second region, which in this case is connected to the liner 110 (in this case by means of at least one weld seam) and which is surrounded at least in certain regions by the fiber-reinforced layer 120. The face side 142 is in this case spaced apart from the fiber-reinforced layer 120 to such an extent i) that the limit temperature is not reached in the fiber-reinforced layer 120, and ii) that the unused toroidal structural space between inner vessel and outer vessel is as small as possible, and that the toroidal structural space is nevertheless sufficient to compensate for pressure-induced and/or temperature-induced changes in length, and the heat dissipation path in the connecting element 144 is of sufficient length.

[0078] The connecting element 144 is of tubular form and inserted into the pot-shaped connecting end piece 140. The connecting element 144 is formed at least in certain regions from a fiber composite material in order to thus minimize the introduction of heat into the inner vessel and compensate for any vibrations. The outer surface of the connecting element 144 lies in this case at least in certain regions against the inner surface of the peripheral wall 143 (cf.

[0079] FIG. 2) and may form a floating bearing. At least one electrical line 133 may be accommodated in the interior of the connecting element 144. The at least one electrical line supplies electrical energy to the heating element 130 and provides the electrical signals for the open-loop and/or closed-loop control of the heating element 130. The ratio of the heating length lh, projecting into the inner vessel 100, of the heating element 130 to the total length L100 of the inner vessel 100 lies between 0.1 and 0.8 or between 0.25 to 0.5.

[0080] The pressure vessel furthermore comprises a pressure relief device 170. The pressure relief device 170 does not serve for the filling of the pressure vessel or for the extraction of fuel for the energy converter 500. Rather, the pressure relief device 170 generally serves for the relief of pressure in the event of a malfunction or fault or for the relief of pressure during very long standstill periods. The filling and extraction line 410 connects the internal volume I of the inner vessel 100 to a line system that is provided in the evacuated space V. The filling and extraction line 410 in this case comprises a T-piece that is fluidically connected to the pressure relief line 171. The pressure relief line 171 could likewise open directly in the internal volume I. In this case, two thermally activatable pressure relief apparatuses (TPRDs) 172, 174 are provided in the pressure relief line 171. For example, for this purpose, the pressure relief line 171 may be formed from multiple line elements, between which in each case one thermally activatable pressure relief apparatus 172, 174 is provided. If, for example, a thermal event occurs adjacent to the pressure relief apparatus 174, then the pressure relief apparatus 174 opens, for example by virtue of a fusible link melting or a glass ampule being destroyed. The fuel then escapes abruptly before the thermal event can cause a rupture of the inner vessel 100. Such an arrangement of the TPRDs is particularly space-saving and operationally reliable. The overpressure discharge valve 177 may particularly advantageously also be formed on the pressure relief line 171 and fluidically connected to the pressure relief line 171. It is preferable for the overpressure discharge valve 177 and/or the thermally activatable pressure relief apparatus 174 and/or the rupture element 176 to be formed as close as possible to the first line end 178 or as close as possible to the first end P1. It is advantageously thus possible for the pressure relief line 171 to serve as a heat exchange path such that the cryogenic fuel acts on the components with higher temperatures than at the other end of the pressure relief line 171 directly adjacent to the tank shut-off valve 420. The overpressure discharge valve 177 and/or the thermally activatable pressure relief apparatus 174 and/or the rupture element 176 and/or the overpressure safety valve 177 disclosed here are in this case directly fluidically connected to the internal volume I of the pressure vessel. In other words, no shut-off element (for example valve) that could possibly block the flow path for the relief of pressure is provided between the components and the internal volume I.

[0081] A further pressure relief line 171 branches off in the opposite direction from the T-piece, which further pressure relief line is fluidically connected to the overpressure safety valve 175. The overpressure safety valve 175 may be provided so as to be received in the outer vessel 200 from the outside. It is advantageously thus possible for the overpressure safety valve 175 to be exchanged without the need for additional access to the evacuated space V for this purpose.

[0082] The overpressure discharge valve 177 is fluidically connected to a fuel converter 180. If the fuel pressure increases to a value above the triggering pressure of the overpressure discharge valve 177, then fuel can flow out of the internal volume I into the fuel converter 180 via the pressure relief line 171 and via the overpressure discharge valve 177. The fuel converter 180 is configured to catalytically convert the fuel. It is thus the case that no or only negligibly little fuel passes into the surroundings. A throttle for limiting the discharge fuel mass flow may be provided in the fuel converter 180 or upstream of the fuel converter 180. If the fuel cannot be discharged, or cannot be sufficiently discharged, via the overpressure discharge valve 177 and the fuel converter 180, the pressure in the internal volume increases further until the triggering pressure of the overpressure safety valve 175 is reached. The triggering pressure of the overpressure safety valve 175 is in this case thus higher than the triggering pressure of the overpressure discharge valve 177. When the overpressure safety valve 175 is open, a mass flow can escape, which mass flow may be greater than the mass flow that can be catalytically converted by means of the fuel converter 180. The fuel can expediently be discharged via a suitable fuel outlet into the surroundings or into a suction-type fuel extraction device. For this purpose, channels may for example be provided which lead to a roof fin in the vehicle roof, via which the fuel escapes. If the overpressure safety valve 175 were to malfunction, then the pressure in the internal volume I could increase further until the triggering pressure of the rupture element 176 is reached, which is higher than the triggering pressure of the overpressure safety valve 175. If the rupture element 176 ruptures, then a rapid relief of pressure also occurs. The overpressure safety valve 175 and the rupture element 176 are of different construction, such that there is less likelihood of a failure of both components owing to the same fault. It is advantageous here if the overpressure safety valve 175 and the rupture element 176 are configured so as to be spaced apart from one another to a great extent. By virtue of the overpressure safety valve 175 being formed on the top side and the rupture element 176 being formed on the bottom side of the pressure vessel, there is increased likelihood that, in a normal situation and in an upside-down situation, even in the event of deformation of the bodyshell, the fuel can still be reliably released. For the same reason, it is particularly preferable here for the rupture element 176 and the overpressure safety valve 175 to be provided at different ends P1, P2 of the pressure vessel.

[0083] The tank shut-off valve 420 is also directly fluidically connected to the internal volume I of the inner vessel 100 in this case. The tank shut-off valve 420 is shown merely schematically. The tank shut-off valve is an electrically actuatable and normally closed valve. Downstream of the tank shut-off valve 420, the extraction path 411 extends to the energy converter 500. A heat exchanger 190 is provided in the extraction path, which heat exchanger has a coolant inflow path 192 and a coolant outflow path 194. The coolant may be extracted from a coolant circuit of the motor vehicle.

[0084] FIG. 2 shows a schematic cross-sectional view of the inner vessel 100. The inner vessel 100 comprises the liner 110, which is surrounded by the fiber-reinforced layer 120. At the two ends of the inner vessel 100, there is provided in each case one connecting end piece 140 (also referred to as boss), which connecting end pieces are in this case of identical configuration for the sake of simplicity. Here, a barrier layer 150 is provided so as to be spaced apart by a gap S. The barrier layer 150 is in this case manufactured from a steel alloy. The barrier layer 150 together with the fiber-reinforced layer 120 forms a substantially gas-tight space GR. Here, the barrier layer 150 forms a body that surrounds the fiber-reinforced layer 120 of the inner vessel 100 completely and in substantially gas-tight fashion, such that the vacuum of the evacuated space V does not degrade in a functionally detrimental manner. The outer vessel 200 and further elements of the pressure vessel have been omitted for the sake of simplicity.

[0085] A test connection which may be provided, and through which the substantially gas-tight space GR may be accessible from the outside, is not shown. If any gases escape from the fiber-reinforced layer, these cannot escape into the evacuated space V, owing to the sealing action of the barrier layer 150. The gases collect in the substantially gas-tight space GR. In one configuration, the escaped gases can be extracted through the test connection.

[0086] The gap S may be selected such that, even in the event of maximum expansion of the inner vessel 100 in a radial direction, the fiber-reinforced layer 120 does not make contact with the barrier layer 150. For the compensation of length expansions in an axial direction, the barrier layer 150 in this case comprises a length compensation device 152. The length compensation device 152 is configured as a corrugated bellows or membrane bellows. The length compensation device 152 is fastened in substantially gas-tight fashion by way of a first end P1 to an annular plate 154 and by way of a second end P2 to a cap part 157 (also referred to as dome part). The one or more cap part(s) 157 is/are in turn connected in substantially gas-tight fashion to a generally cylindrical central part 156. In this configuration of the barrier layer 150, the barrier layer comprises an annular plate 154, two cap parts 157, one or two central part(s) 156 and a corrugated bellows 152. These parts are preferably produced from a metal material (in this case from a steel alloy) and particularly preferably from the same material and are cohesively connected to one another so as to close off the substantially gas-tight space GR to the outside. Depending on the manufacturing concept, the barrier layer 150 may be formed by fewer or more parts or semifinished parts. The annular plate 154 is welded in its center to the connecting end piece 140. In other words, the plate 154 is the connecting piece between corrugated bellows and boss. At its radial edge, the plate 154 is welded to the corrugated bellows. Even though only one annular plate 154 and only one length compensation device 152 are shown here, it would also be possible for in each case one annular plate 154 and one length compensation device 152 to be provided at both ends.

[0087] If the inner vessel 100 expands in an axial direction (illustrated here by an arrow), then the second end P2 moves outward. This change in length is simultaneously “locally” compensated at the second end P2 by the length compensation device 152. Weld seams are illustrated in FIG. 2 as black dots. Fewer or more weld seams may be provided depending on the configuration of the inner vessel 100.

[0088] In the context of the technology disclosed here, the expression “substantially” (for example “substantially vertical axis”) encompasses in each case the exact characteristic or the exact value (for example “vertical axis”) and in each case deviations that are not of significance for the function of the characteristic/of the value (for example “tolerable deviation from a vertical axis”).

[0089] The above description of the present invention serves merely for illustrative purposes and not for the purposes of limiting the invention. In the context of the invention, various changes and modifications are possible without departing from the scope of the invention and its equivalents. In particular, the features disclosed in conjunction with [0090] i) the pot-shaped connecting element (inner tank mounting); [0091] ii) the heating device; [0092] iii) the barrier layer; [0093] iv) the discharge valve; [0094] v) the rupture element; [0095] vi) the refueling system; and [0096] vii) the sensor arrangement,
are in each case individually functionally independent and are also usable with other pressure vessels and in particular with other cryogenic pressure vessels. The combination thereof is however particularly advantageous.