Tank temperature sensor

Abstract

To provide a tank temperature sensor that can accurately detect the temperature of gas in a tank by restraining heat dissipation to the outside.SOLUTION: A tank temperature sensor 10 is a sensor inserted into a small-diameter tank 1, and for detecting the temperature of gas stored in the small-diameter tank 1, and comprises: a first cylindrical body 14 housing a temperature detection element 11, and a portion of a pair of lead wires 12 electrically connected to the temperature detection element 11, and comprising a closed end part 14a, and an opened end part 14b on the side opposite thereto; and a second cylindrical body 15 housing a portion of the lead wires 12, and comprising an inserted end part 15a inserted into the opened end part 14b, and an extending end part 15b extending to the outside of the small-diameter tank 1. A heat insulation part 20 is provided between the inserted end part 15a and the first cylindrical body 14 in at least one of an axial direction and a circumferential direction of the second cylindrical body 15.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a tank temperature sensor, and more particularly to a tank temperature sensor that is applied to a small diameter tank. [Background technology]

[0002] Fuel cell vehicles are equipped with a tank that stores fuel gas such as hydrogen gas. To detect the temperature of the gas stored in the tank, a temperature sensor is inserted into the tank, and the gas temperature is detected via the inserted temperature sensor (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-190523 Summary of the Invention [Problem to be solved by the invention]

[0004] However, because such temperature sensors are attached to a metal tank valve attached to the nozzle of the tank, they are easily affected by outside air temperature, making it difficult to accurately detect the temperature of the gas inside the tank. In particular, there has been a recent shift to smaller-diameter tanks with smaller tank necks in order to reduce the axial load on the tank. As a result, an integrated structure in which the temperature sensor is fixed to the end cap of small-diameter tanks is often adopted. However, with an integrated structure in which the temperature sensor and end cap are integrated, heat is easily dissipated to the outside through the end cap, which is made of metal, making it even more difficult to accurately detect the temperature of the gas inside the tank.

[0005] If the temperature of the gas inside the tank cannot be detected accurately, various problems will occur. For example, when hydrogen gas is filled into a small-diameter tank from a hydrogen station, the controller at the hydrogen station controls the amount of hydrogen gas to be filled based on the temperature and internal pressure of the gas inside the tank. Therefore, if the temperature of the gas inside the tank cannot be detected accurately, the target filling amount will not be reached.

[0006] The present invention has been made to solve these technical problems, and aims to provide a tank temperature sensor that suppresses heat radiation to the outside and can accurately detect the temperature of gas inside the tank. [Means for solving the problem]

[0007] The tank temperature sensor of the present invention is a tank temperature sensor that is inserted into the inside of a tank and detects the temperature of gas stored in the tank, and is characterized in that it comprises: a first cylindrical body that houses a temperature detection element and a portion of a pair of lead wires electrically connected to the temperature detection element, and has a closed end and an open end on the opposite side; and a second cylindrical body that houses a portion of the pair of lead wires, and has an insertion end that is inserted into the open end and an extension end that extends outside the tank, and in that an insulating portion is provided between the insertion end of the second cylindrical body and the first cylindrical body in at least one of the axial and circumferential directions of the second cylindrical body.

[0008] In the tank temperature sensor according to the present invention, a heat insulating portion is provided between the first cylinder and the insertion end of the second cylinder in at least one of the axial and circumferential directions of the second cylinder, and the heat insulating portion serves to improve the heat insulating performance between the first cylinder housing the temperature detection element and the second cylinder, thereby suppressing heat radiation to the outside and enabling accurate detection of the temperature of the gas in the tank.

[0009] In the tank temperature sensor according to the present invention, the heat insulating portion is preferably an air layer formed by tapering or stepping the outer edge corners of the insertion end, an air layer formed by roughening the portion of the insertion end facing the first cylindrical body, a resin layer provided between the insertion end and the first cylindrical body, or a heat insulating grease layer formed by applying heat insulating grease to the portion of the insertion end facing the first cylindrical body. This allows for a wider variety of heat insulating portions, and by using these variations according to the structure of the temperature sensor, it is possible to provide an inexpensive tank temperature sensor that can accurately detect the temperature of the gas in the tank.

[0010] In the tank temperature sensor according to the present invention, a first resin sealant is provided inside the first cylindrical body to seal the temperature detection element and a portion of the pair of lead wires, and a second resin sealant is provided inside the second cylindrical body to seal a portion of the pair of lead wires. The thermal conductivity of the resin used in the first resin sealant is preferably higher than the thermal conductivity of the resin used in the second resin sealant. This configuration improves the thermal conductivity of the temperature detection element sealed in the first resin sealant, thereby improving the thermal sensitivity of the temperature detection element and further suppressing heat dissipation to the outside via the second cylindrical body. As a result, the temperature of the gas in the tank can be detected more accurately.

[0011] In the tank temperature sensor according to the present invention, it is preferable that the resins used in the first and second resin sealants are both epoxy resins, and that the thermal conductivity of the epoxy resin used in the first resin sealant is 2.5 times or more that of the epoxy resin used in the second resin sealant, thereby enabling more accurate detection of the temperature of the gas inside the tank. [Effects of the Invention]

[0012] According to the present invention, heat radiation to the outside can be suppressed and the temperature of the gas inside the tank can be accurately detected. [Brief explanation of the drawings]

[0013] [Figure 1] 3 is a diagram showing an installation state of the tank temperature sensor according to the first embodiment. FIG. [Figure 2] FIG. 2 is a cross-sectional view showing the tank temperature sensor according to the first embodiment. [Figure 3] FIG. 6 is a cross-sectional view showing a tank temperature sensor according to a second embodiment. [Figure 4] FIG. 10 is a cross-sectional view showing a tank temperature sensor according to a third embodiment. [Figure 5] FIG. 10 is a cross-sectional view showing a tank temperature sensor according to a fourth embodiment. [Figure 6] FIG. 10 is a cross-sectional view showing a tank temperature sensor according to a fifth embodiment. [Figure 7] 1A and 1B are diagrams illustrating examples and comparative examples. [Figure 8] 1A and 1B are diagrams illustrating examples and comparative examples. DETAILED DESCRIPTION OF THE INVENTION

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A tank temperature sensor according to an embodiment of the present invention will be described below with reference to the drawings. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicated description will be omitted.

[0015] In the following embodiment, an example in which the tank temperature sensor is applied to a small diameter tank will be described, but the tank temperature sensor of the present invention can also be applied to tanks other than small diameter tanks.

[0016] In addition, to avoid complication of explanation, in the following explanation, the "tank temperature sensor" may be abbreviated to "temperature sensor."

[0017] [First embodiment] FIG. 1 is a diagram showing the installation state of a tank temperature sensor according to the first embodiment. The tank temperature sensor 10 of this embodiment is inserted into a small-diameter tank 1 and is used to detect the temperature of gas stored inside the small-diameter tank 1. Note that a small-diameter tank refers to one in which the mouth of the tank (i.e., the opening 6 of the liner 2, which will be described later) is small in order to reduce the contact area between the tank and the high-pressure gas and to reduce the axial load on the tank. Here, the structure of the small-diameter tank 1 will first be briefly described.

[0018] The small diameter tank 1 is a high-pressure container for storing, for example, hydrogen gas, and includes a substantially cylindrical liner 2 with both ends rounded into a dome shape, and a fiber-reinforced resin layer 3 covering the outer circumferential surface of the liner 2. The liner 2 is formed from a resin material that has gas barrier properties against hydrogen gas, and includes a cylindrical body 4 and a pair of dome sections 5 (only one dome section is shown in FIG. 1) provided at both ends of the body 4 in the axial L direction.

[0019] The dome portion 5 has a substantially hemispherical shape. A cylindrical opening 6 is provided at the end of the dome portion 5 opposite the body portion 4. The opening 6 has an outer diameter smaller than that of the dome portion 5 and is disposed so as to protrude from the dome portion 5 along the direction of the axis L. The opening 6 functions as a fill port for filling the inside of the small-diameter tank 1 with hydrogen gas, or as an outlet port for discharging hydrogen gas stored inside the small-diameter tank 1.

[0020] A nozzle portion 7 is attached to the outside of the fiber reinforced resin layer 3 that covers the opening 6. The nozzle portion 7 is made of a metal material such as stainless steel or an aluminum alloy and processed into a cylindrical shape, and has a cylindrical nozzle main body portion 71 that extends along the axis L, and a flange portion 72 that is connected to one end of the nozzle main body portion 71 and protrudes in the radial direction.

[0021] Furthermore, a male screw portion 73 that screws into a lid-shaped member 8, which will be described later, is formed on the outer peripheral wall of the mouthpiece main body 71. A saw-like locking claw portion 74 is formed on the inner peripheral wall of the mouthpiece main body 71. The mouthpiece 7 is fixed to the fiber reinforced resin layer 3 by the locking claw portion 74 biting into the outer peripheral portion of the fiber reinforced resin layer 3.

[0022] The opening 6 of the liner 2 is closed by a lid-like member 8. The lid-like member 8 is, for example, an end cap, and has a substantially disk-shaped main body 81 and a side wall 82 that is connected to the outer periphery of the main body 81 and extends in the axial direction L. A through hole 83 is provided in the center of the main body 81 for allowing a lead wire 12 of a temperature sensor 10 (described later) to extend to the outside. A female thread 84 is formed on the inner circumferential wall of the side wall 82, which screws into the male thread 73 of the base 7. The lid-like member 8 having such a structure is made of a metal material such as an aluminum alloy.

[0023] As shown in FIG. 1, when installed in a small-diameter tank 1, the tank temperature sensor 10 is inserted into the small-diameter tank 1 through an opening 6 in a liner 2 and fixed to the small-diameter tank 1 by a lid-like member 8.

[0024] 2 is a cross-sectional view showing a tank temperature sensor according to the first embodiment. The tank temperature sensor 10 includes a temperature detection element 11 for detecting temperature, a pair of lead wires 12 electrically connected to the temperature detection element 11, a glass sealing body 13 that seals the temperature detection element 11 and the connection between the temperature detection element 11 and the lead wires 12, a first cylindrical body 14 that houses the glass sealing body 13 and a portion of the lead wires 12, and a second cylindrical body 15 that is connected to the first cylindrical body 14 and houses a portion of the lead wires 12.

[0025] The first cylindrical body 14 has a small-diameter cylindrical portion 141 formed with a relatively small outer diameter, and a large-diameter cylindrical portion 142 formed with a relatively large outer diameter and integrated with the small-diameter cylindrical portion 141. The first cylindrical body 14 is formed with a hat-shaped cross section by the small-diameter cylindrical portion 141, the large-diameter cylindrical portion 142, and a step portion 143 connecting the small-diameter cylindrical portion 141 and the large-diameter cylindrical portion 142.

[0026] One end of the small diameter cylindrical portion 141 is closed, and constitutes the closed end portion 14a of the first cylindrical body 14. A first resin sealing body 16 for sealing the glass sealing body 13 and a part of the lead wire 12 is provided inside the small diameter cylindrical portion 141. The first resin sealing body 16 is in close contact with the first cylindrical body 14 so that no gap is formed between the first resin sealing body 16 and the inner wall of the first cylindrical body 14. Note that instead of the first resin sealing body 16, a material such as alumina (Al2O3) may be filled inside the small diameter cylindrical portion 141 to fix the glass sealing body 13 and a part of the lead wire 12.

[0027] The large diameter cylindrical portion 142 is connected to the small diameter cylindrical portion 141 via a step portion 143. The end of the large diameter cylindrical portion 142 that is away from the small diameter cylindrical portion 141 is open and forms the open end portion 14b of the first cylindrical body 14.

[0028] The first cylindrical body 14 having such a structure is integrally formed from a metal material such as an aluminum alloy, stainless steel, etc. The thermal conductivity of stainless steel is lower than that of aluminum alloy (for example, the thermal conductivity of SUS316 is about 1 / 10 of that of A6061), and from the viewpoint of suppressing heat dissipation to the outside of the small-diameter tank 1, it is preferable that the first cylindrical body 14 be formed from stainless steel, which has a relatively low thermal conductivity.

[0029] The second cylindrical body 15 is formed in a substantially cylindrical shape and is coaxially connected to the first cylindrical body 14. The second cylindrical body 15 has an insertion end 15a that is inserted into the open end 14b of the first cylindrical body 14 and an extension end 15b that extends outward from the small-diameter tank 1. The insertion end 15a is formed so that its outer diameter is slightly smaller than the inner diameter of the large-diameter cylindrical portion 142 of the first cylindrical body 14. A circumferential groove 151 is provided on the outer peripheral wall of the insertion end 15a. An O-ring 17 is fitted into the circumferential groove 151 to seal between the first cylindrical body 14 and the second cylindrical body 15 (more specifically, between the large-diameter cylindrical portion 142 of the first cylindrical body 14 and the insertion end 15a of the second cylindrical body 15).

[0030] The extending end portion 15b is formed in a disk shape extending in a radial direction perpendicular to the axial direction of the second cylindrical body 15, and has an abutment surface 152 that abuts against the end surface of the small-diameter tank 1 on the opening 6 side. A second resin sealing body 18 that seals a part of the lead wire 12 is provided inside the second cylindrical body 15. The second resin sealing body 18 is in close contact with the second cylindrical body 15 so that no gap is generated between the second resin sealing body 18 and the inner wall of the second cylindrical body 15.

[0031] The second cylindrical body 15 having such a structure is formed from a metal material such as an aluminum alloy, stainless steel, etc. The thermal conductivity of stainless steel is lower than that of aluminum alloy (for example, the thermal conductivity of SUS316 is about 1 / 10 of the thermal conductivity of A6061), and from the viewpoint of suppressing heat dissipation to the outside of the small-diameter tank 1, it is preferable that the second cylindrical body 15 be formed from stainless steel, which has a relatively low thermal conductivity.

[0032] Furthermore, a circumferential groove is provided on the outer peripheral wall of the second cylindrical body 15, and an O-ring 19 is fitted into the circumferential groove to seal between the second cylindrical body 15 and the opening 6 of the small diameter tank 1 (more specifically, between the outer peripheral wall of the second cylindrical body 15 and the inner peripheral wall of the opening 6). In this way, airtightness between the temperature sensor 10 and the small diameter tank 1 can be ensured.

[0033] The second cylindrical body 15 and the first cylindrical body 14 are connected to each other by crimping the large diameter cylindrical portion 142 with the insertion end portion 15a of the second cylindrical body 15 inserted into the inside of the large diameter cylindrical portion 142 of the first cylindrical body 14.

[0034] The temperature sensor 10 configured as described above is attached to the small-diameter tank 1 by inserting the rest of the second cylindrical body 15, except for the extended end 15b, into the small-diameter tank 1, and sandwiching the extended end 15b between the small-diameter tank 1 and the lid-like member 8, with the abutment surface 152 of the second cylindrical body 15 abutting against the liner 2, the fiber-reinforced resin layer 3, and the end faces of the nozzle portion 7. When attached to the small-diameter tank 1, the large-diameter cylindrical portion 142 of the first cylindrical body 14 does not come into contact with the small-diameter tank 1 (see FIG. 1). In this manner, heat radiation to the outside of the small-diameter tank 1 via the first cylindrical body 14 and the small-diameter tank 1 can be suppressed.

[0035] In this embodiment, the thermal conductivity of the resin used in the first resin sealant 16 is higher than the thermal conductivity of the resin used in the second resin sealant 18. Preferably, the resins used in the first resin sealant 16 and the second resin sealant 18 are both epoxy resins. The thermal conductivity of the epoxy resin used in the first resin sealant 16 is 2.5 times or more the thermal conductivity of the epoxy resin used in the second resin sealant 18.

[0036] Furthermore, a heat insulating section 20 is provided between the insertion end 15a of the second cylindrical body 15 and the first cylindrical body 14 in the axial and circumferential directions of the second cylindrical body 15. The heat insulating section 20 is an air layer formed, for example, by tapering the outer edge corners of the insertion end 15a. That is, an inclined surface is formed at the outer edge corners of the insertion end 15a so as to rise from the outside toward the inside of the second cylindrical body 15. By doing so, a space is created in the axial and circumferential directions of the second cylindrical body 15, surrounded by the inclined surface of the second cylindrical body 15 and the large-diameter cylindrical section 142 and the stepped section 143 of the first cylindrical body 14, and the air remaining in this space forms an air layer (i.e., the heat insulating section 20).

[0037] In the temperature sensor 10 having such a structure, the air layer surrounded by the inclined surface of the second cylindrical body 15 and the large-diameter cylindrical portion 142 and step portion 143 of the first cylindrical body 14 constitutes the heat insulating portion 20, and the heat insulating portion 20 serves to improve the heat insulating performance between the first cylindrical body 14 and the second cylindrical body 15 that house the temperature detection element 11. This makes it possible to suppress heat radiation to the outside via the second cylindrical body 15, and to accurately detect the temperature of the gas inside the small-diameter tank 1.

[0038] Furthermore, the first cylindrical body 14 that houses the temperature detection element 11 has a hat-shaped cross section formed by a small-diameter cylindrical portion 141, a large-diameter cylindrical portion 142, and a step portion 143 that connects the small-diameter cylindrical portion 141 and the large-diameter cylindrical portion 142. This increases the heat-receiving surface area of the first cylindrical body 14 that houses the temperature detection element 11, and reduces the heat capacity (heat mass) of the first cylindrical body 14 on the temperature detection element 11 side, thereby improving the thermal sensitivity of the temperature detection element 11. As a result, the temperature of the gas inside the small-diameter tank 1 can be detected more accurately.

[0039] Furthermore, by sealing the gap between the first cylindrical body 14 and the second cylindrical body 15 with an O-ring 17, the first cylindrical body 14 housing the temperature detection element 11 is separated from the second cylindrical body 15, thereby reducing the heat capacity of the entire first cylindrical body 14. This further improves the thermal sensitivity of the temperature detection element 11.

[0040] Furthermore, the thermal conductivity of the epoxy resin used in the first resin sealing body 16 is at least 2.5 times that of the epoxy resin used in the second resin sealing body 18. In this way, by using a high thermal conductivity epoxy resin to seal the temperature detection element 11 and a low thermal conductivity epoxy resin to seal the other parts, the thermal conductivity to the temperature detection element 11 can be increased, thereby improving the thermal sensitivity of the temperature detection element 11 and further suppressing heat radiation to the outside via the second cylindrical body 15. As a result, the temperature of the gas inside the small-diameter tank 1 can be detected more accurately.

[0041] In this embodiment, the heat insulating portion 20 is an air layer formed by tapering the outer edge corners of the insertion end 15a of the second cylindrical body 15, but the heat insulating portion may be an air layer formed by making the outer edge corners of the insertion end 15a step-shaped. Also, the heat insulating portion may be an air layer formed by roughening the portion of the insertion end 15a facing the first cylindrical body 14.

[0042] When roughening the portion of the insertion end 15a facing the first cylindrical body 14, for example, the surface of the insertion end 15a facing the step portion 143 of the first cylindrical body 14 is roughened by mechanical or chemical treatment. Specifically, for example, laser processing, shot blasting, or etching is performed on the surface of the insertion end 15a facing the step portion 143 so that multiple projections and depressions are formed on the surface. The multiple projections and depressions thus formed also function as air layers, and therefore have the same effect as the heat insulating section 20.

[0043] [Second embodiment] Next, a second embodiment of a tank temperature sensor will be described with reference to Fig. 3. The tank temperature sensor 10A of this embodiment differs from the first embodiment described above in the configuration of the heat insulating portion 21. Only the differences will be described below.

[0044] Fig. 3 is a cross-sectional view showing a tank temperature sensor according to the second embodiment. As shown in Fig. 3, a heat insulating portion 21 made of an air layer is provided between the insertion end portion 15a of the second cylindrical body 15 and the first cylindrical body 14 in the axial direction of the second cylindrical body 15. That is, in the axial direction of the second cylindrical body 15, the insertion end portion 15a and the step portion 143 of the first cylindrical body 14 are connected so as to have a gap therebetween without abutting each other. The air remaining in this gap forms an air layer (i.e., the heat insulating portion 21).

[0045] The temperature sensor 10A having such a structure can provide the same effects as the temperature sensor 10 of the first embodiment, and can also provide more variations in the heat insulating portion.

[0046] [Third embodiment] Next, a third embodiment of a tank temperature sensor will be described with reference to Fig. 4. The tank temperature sensor 10B of this embodiment differs from the first embodiment described above in the configuration of the heat insulating portion 22. Only the differences will be described below.

[0047] Fig. 4 is a cross-sectional view showing a tank temperature sensor according to the third embodiment. As shown in Fig. 4, a heat insulating portion 22 made of a resin layer is provided between the insertion end portion 15a of the second cylindrical body 15 and the first cylindrical body 14 in the axial direction of the second cylindrical body 15. That is, the heat insulating portion 22 made of a resin layer is interposed between the insertion end portion 15a and the step portion 143 of the first cylindrical body 14 in the axial direction of the second cylindrical body 15. The resin used for the heat insulating portion 22 is, for example, an epoxy resin having a lower thermal conductivity than the first resin sealing body 16, similar to the second resin sealing body 18.

[0048] The temperature sensor 10B having such a structure can provide the same effects as the temperature sensor 10 of the first embodiment. This also increases the variety of heat insulating parts.

[0049] [Fourth embodiment] Next, a fourth embodiment of a tank temperature sensor will be described with reference to Fig. 5. The tank temperature sensor 10C of this embodiment differs from the first embodiment described above in the configuration of the heat insulating portion 23. Only the differences will be described below.

[0050] FIG. 5 is a cross-sectional view showing a tank temperature sensor according to a fourth embodiment. As shown in FIG. 5, a heat insulating portion 23 made of a heat insulating grease layer is provided between the insertion end 15a of the second cylindrical body 15 and the first cylindrical body 14 in the axial and circumferential directions of the second cylindrical body 15. That is, an axial heat insulating grease layer 231 formed by applying heat insulating grease to the surface of the insertion end 15a facing the step portion 143 of the first cylindrical body 14 in the axial direction of the second cylindrical body 15 is provided. Furthermore, a circumferential heat insulating grease layer 232 formed by applying heat insulating grease to the outer peripheral wall surface of the insertion end 15a facing the open end 14b of the first cylindrical body 14 in the circumferential direction of the second cylindrical body 15 is provided. The axial heat insulating grease layer 231 and the circumferential heat insulating grease layer 232 constitute the heat insulating portion 23. Well-known heat insulating grease is used as the heat insulating grease.

[0051] The temperature sensor 10C having such a structure can provide the same effects as the temperature sensor 10 of the first embodiment. This also increases the variety of heat insulating parts.

[0052] [Fifth embodiment] Next, a fifth embodiment of a tank temperature sensor will be described with reference to Fig. 6. As shown in Fig. 6, a tank temperature sensor 10D of this embodiment includes a first cylindrical body 14A that houses a temperature detection element 11 and a portion of a pair of lead wires 12 electrically connected to the temperature detection element 11, and a second cylindrical body 15A that is connected to the first cylindrical body 14A and houses a portion of the pair of lead wires 12.

[0053] The first cylindrical body 14A has a closed end 14a and an open end 14b on the opposite side. The second cylindrical body 15A has an insertion end 15a that is fitted onto the open end 14b of the first cylindrical body 14 and an extension end 15b that extends outward from the small-diameter tank 1. That is, in this embodiment, the second cylindrical body 15A and the first cylindrical body 14A are connected to each other by crimping the insertion end 15a with the insertion end 15a of the second cylindrical body 15A fitted onto the open end 14b of the first cylindrical body 14A. Note that other structures of the temperature sensor 10D are similar to those of the first embodiment described above, and therefore, repeated explanations will be omitted.

[0054] Furthermore, the temperature sensor 10D of this embodiment is longer than the temperature sensors of the first to fourth embodiments described above in order to increase the heat-receiving surface area. When attached to the small-diameter tank 1, the temperature sensor 10D has its tip (more specifically, the tip of the closed end 14a) inserted deeper into the small-diameter tank 1 than the tips of the temperature sensors of the first to fourth embodiments. In this embodiment, the temperature sensor 10D is formed so that the tip of the closed end 14a reaches near the boundary between the body portion 4 and the dome portion 5 of the liner 2.

[0055] In the temperature sensor 10D having such a structure, the tip of the closed end 14a is formed to reach near the boundary between the body portion 4 and the dome portion 5 of the liner 2, thereby increasing the heat-receiving surface area of the temperature sensor 10D. This makes it possible to suppress heat radiation to the outside and accurately detect the temperature of the gas inside the small-diameter tank 1.

[0056] [Examples and Comparative Examples] Next, an example and a comparative example will be described with reference to Figures 7 and 8. Here, the temperature sensor 10D of the fifth embodiment (example) and a conventional temperature sensor (comparative example) were used to examine the change in the filling rate when hydrogen gas is filled into a small diameter tank from a hydrogen station. In the example and comparative example, all other devices and conditions were the same except for the temperature sensor used.

[0057] As described above, when hydrogen gas is being filled into a small-diameter tank from a hydrogen station, the controller at the hydrogen station controls the amount of hydrogen gas to be filled based on the gas temperature and internal tank pressure detected by a temperature sensor. Typically, the controller at the hydrogen station automatically stops filling hydrogen gas when the filling rate (SOC: State of Charge) reaches 98%. When a conventional temperature sensor is used (before the countermeasures were implemented in Figures 7 and 8), filling ends when the gas temperature detected by the temperature sensor is 42°C and the internal tank pressure is 75 MPa. However, because the actual average gas temperature inside the small-diameter tank is 55°C, the SOC is 95% (temperature T = 55°C, pressure P = 75 MPa). Therefore, a 3% difference occurred between the target SOC and the actual SOC. As shown in Figure 8, the deviation between the target SOC and the actual SOC was 3%.

[0058] This is because by detecting a low temperature of the hydrogen gas in the small-diameter tank, the controller at the hydrogen station estimates that the density of the hydrogen gas in the small-diameter tank is high, and as a result, even if the amount of hydrogen gas filled in the small-diameter tank is less than the actual amount, the estimated amount of hydrogen gas filled is considered to have reached the target amount.

[0059] In contrast, when the temperature sensor 10D of the fifth embodiment was used (after the countermeasures were taken in FIGS. 7 and 8), the deviation between the target SOC and the actual SOC was 0.1%. This improvement in the deviation between the target SOC and the actual SOC indicates that the temperature of the gas in the small-diameter tank can be detected more accurately when the temperature sensor 10D of the fifth embodiment is used.

[0060] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various design modifications can be made without departing from the spirit of the present invention as set forth in the claims. [Explanation of symbols]

[0061] 1: small diameter tank, 2: liner, 3: fiber reinforced resin layer, 6: opening, 7: nozzle portion, 8: lid-shaped member, 10, 10A, 10B, 10C, 10D: tank temperature sensor, 11: temperature detection element, 12: lead wire, 13: glass sealant, 14: first cylindrical body, 14a: closed end, 14b: open end, 15: second cylindrical body, 15a: insertion end, 15b: extension end, 16: first resin sealant, 17, 19: O-ring, 18: second resin sealant, 20, 21, 22, 23: heat insulating portion, 141: small diameter cylindrical portion, 142: large diameter cylindrical portion, 143: step portion, 151: circumferential groove, 152: contact surface, 231: axial heat insulating grease layer, 232: circumferential heat insulating grease layer

Claims

1. A tank temperature sensor that is inserted into a tank and detects the temperature of gas stored in the tank, a first cylindrical body that houses the temperature detection element and a portion of a pair of lead wires electrically connected to the temperature detection element, and has a closed end and an open end opposite the closed end; a second cylindrical body that houses a portion of the pair of lead wires and has an insertion end that is inserted into the open end and an extension end that extends outward from the tank; Equipped with a heat insulating portion is provided between the insertion end portion of the second cylindrical body and the first cylindrical body in at least one of the axial direction and the circumferential direction of the second cylindrical body, a first resin sealing body that seals the temperature detection element and a portion of the pair of lead wires is provided inside the first cylindrical body; a second resin sealing body that seals a portion of the pair of lead wires is provided inside the second cylindrical body; The tank temperature sensor is characterized in that the thermal conductivity of the resin used in the first resin sealing body is higher than the thermal conductivity of the resin used in the second resin sealing body.

2. The temperature sensor for a tank as described in claim 1, wherein the insulating portion is an air layer formed by tapering or stepping the outer edge corners of the insertion end, an air layer formed by roughening the portion of the insertion end facing the first cylindrical body, a resin layer provided between the insertion end and the first cylindrical body, or an insulating grease layer formed by applying insulating grease to the portion of the insertion end facing the first cylindrical body.

3. the resins used in the first resin encapsulant and the second resin encapsulant are both epoxy resins; 2. The tank temperature sensor according to claim 1, wherein the thermal conductivity of the epoxy resin used in the first resin sealing body is at least 2.5 times the thermal conductivity of the epoxy resin used in the second resin sealing body.

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