Method for filling a fuel gas tank with fuel gas, fuel gas tank, and fuel gas tank system

Abstract

The present invention relates to a method for filling a storage volume (2) of a fuel gas tank (1) with fuel gas, wherein the fuel gas is introduced into the storage volume (2) via a supply line (3) having an integrated tank valve (4), and the temperature of the fuel gas in the region of a stagnation point (7) formed by a sensor (5) and / or a holder (8) accommodating the sensor (5) is detected by a sensor (5) integrated in the supply line (3). Furthermore, the present invention relates to a fuel gas tank (1) and a fuel gas tank system comprising at least one fuel gas tank (1) according to the present invention.

Description

Technical Field

[0001] The present invention relates to a method for filling a fuel gas tank with a fuel gas. The fuel gas can be, for example, hydrogen or natural gas. This type of fuel gas is required, for example, by a fuel cell vehicle or a vehicle having a gas engine.

[0002] Furthermore, the present invention relates to a fuel gas tank for a fuel gas tank system, and a fuel gas tank system including at least one fuel gas tank according to the present invention.

Background Art

[0003] In a vehicle operated by a fuel gas, such as hydrogen, the fuel gas is generally stored in a fuel gas tank under pressure. In the case of hydrogen, the pressure can be up to 70 MPa. The temperature in the fuel gas tank can then rise up to 85°C. The temperature limit is then usually predetermined by the material of the fuel gas tank, and carbon fiber reinforced plastic ("CFRP") is often used as the material. When using a CFRP material, if the temperature exceeds 85°C, the plastic required for fixing the carbon fibers, especially the synthetic resin, becomes too soft, and as a result, the required strength of the fuel gas tank is no longer guaranteed.

[0004] For example, hydrogen exhibits a negative Joule-Thomson effect within this relevant temperature range and is thus heated when refueling a fuel gas tank or a hydrogen tank. To avoid damage to the fuel gas tank, hydrogen is therefore cooled to approximately -40 °C prior to the tank process. Furthermore, an upwardly bent tank lance can be used for filling the fuel gas tank, and the tank lance feeds fresh hydrogen mixed with the tank contents, thereby reducing the temperature rise. As a further measure, the tank temperature can be measured or monitored, and as a result, the tank process can be aborted when the temperature limit is exceeded. This abort must be carried out early so that the temperature limit is reliably observed. A high measurement tolerance will thus act negatively. In general, since determining the mass stored in the fuel gas tank is also carried out based on the tank temperature, a high measurement tolerance will further lead to an error-included calculated tank level or an error-included calculated range of navigation distance.

[0005] For both purposes, it is therefore desirable to obtain as accurate information as possible about the temperature inside the fuel gas tank. However, for observing the temperature limit, the locally occurring maximum temperature is important, whereas for calculating the stored mass, the average temperature is more suitable. Reconciling these two desires is difficult. This is especially so because generally, a thermocouple, a thermistor, or a temperature resistor that can only detect the temperature within the immediate surroundings directly is used for temperature measurement. In addition, based on the limited accessibility of the inner chamber of the tank, the selection of the sensor position is strongly restricted.

[0006] From Patent Document 1, illustratively, a fuel gas tank comprising a tank pipeline, a tank valve for filling the fuel gas tank with fuel gas, and a sensor disposed in the tank pipeline for detecting a state variable of the fuel gas can be seen. The sensor is positioned so as to be located outside the pressurized jet that occurs when filling the fuel gas tank with fuel gas. In this way, the measurement accuracy of the sensor should be improved.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] The problem addressed by the present invention is to ensure compliance with a predetermined temperature limit in order to avoid overloading the fuel gas tank when filling the storage volume of the fuel gas tank with fuel gas.

Means for Solving the Problems

[0009] To solve the above problems, a method having the features of claim 1 and a fuel gas tank having the features of claim 5 are proposed. Advantageous developments of the present invention can be seen in the respective dependent claims. Furthermore, a fuel gas tank system comprising at least one fuel gas tank according to the present invention is presented.

[0010] In a method for filling a storage volume of a fuel gas tank with fuel gas, the fuel gas is introduced into the storage volume via a supply line having an integrated tank valve. At that time, the temperature of the fuel gas in the region of the stagnation point formed by a sensor incorporated in the supply line and / or a holder housing the sensor is detected by the sensor.

[0011] Generally, the flow of the fuel gas introduced into the storage volume is first braked or blocked by the wall surrounding the storage volume, which results in the fuel gas being locally strongly heated within the region of the wall. At this time, a local temperature maximum value exceeding the allowable limit value may occur, and as a result, there is a risk of overloading the fuel gas tank. With the proposed method and the artificial stagnation point formed in the supply line, the occurrence of the local temperature maximum value is moved far away from the wall and into the supply line, where it is detected by the sensor arranged there. In this way, compliance with the predetermined temperature limit can be monitored more simply and with higher reliability to avoid overloading the fuel gas tank.

[0012] In a development form of the present invention, it is proposed to compare the measured value of the sensor with a previously determined temperature limit value and, when the temperature limit value is exceeded, to stop or interrupt the supply process. These further steps are used to reliably prevent overloading of the fuel gas tank. The previously determined temperature limit value is preferably still below the limit value predetermined by the material of the fuel gas tank.

[0013] Preferably, another sensor detects the temperature of the fuel gas outside the region of the stagnation point, for example within the storage volume, and an average value and / or a difference value are obtained from the measured values of both sensors. While the sensor arranged within the region of the stagnation point detects the local temperature maximum or the "total temperature", the "static temperature" can be detected by the above-mentioned other sensor. For this purpose, the above-mentioned other sensor is arranged outside the region of the stagnation point. By forming the average value, in this case, the average temperature within the fuel gas tank can be estimated from the measured values of both sensors, and this average temperature is required for calculating the stored mass. In addition, by forming the difference value, the flow rate of the fuel gas when filling the storage volume with fuel gas can be determined. From the flow rate of the fuel gas, in this case, the mass flow rate of the fuel gas or the mass introduced into the storage volume can be calculated.

[0014] Therefore, as a further measure, it is proposed to derive the flow rate of the fuel gas during the replenishment process from the differential value.

[0015] During the replenishment process, the total temperature and the static temperature are significantly separated from each other. That is, the difference between the measured values of both sensors is large. During the discharge process, assuming that the replenishment path is not used for discharge either, the behavior is reversed. When the difference is small, or when the measured values of both sensors are close to each other, this information can be used for checking the validity of the discharge process.

[0016] After the replenishment process, when an obviously too high temperature occurs in the first sensor, it may be due to an uncontrolled "refilling process" within a fuel gas tank system having a plurality of fuel gas tanks. That is, fuel gas from another fuel gas tank is flowing into the fuel gas tank. In this case, the tank valve can be operationally controlled or closed so as not to exceed a previously determined temperature limit value.

[0017] The first sensor for detecting the total temperature is preferably incorporated into the replenishment path so as to measure only the static component of the temperature when the flow direction of the fuel gas in the replenishment path is reversed. That is, the first sensor is blown directly only in one direction, specifically only in the filling direction. The sensor being blown directly in a flow direction reversed with respect to the filling direction can be particularly prevented by a holder, which causes shielding of the sensor when the flow direction in the replenishment path is reversed.

[0018] The ratio of the total temperature to the static temperature depends on the specific geometry and / or coupling of both sensors. By calibration, possible errors in the measured signals of both sensors can be reduced, and as a result, the measurement accuracy is further increased.

[0019] Furthermore, a fuel gas tank for a fuel gas tank system is proposed. The fuel gas tank has a storage volume that can be filled with fuel gas via a supply line having an integrated tank valve. Furthermore, the fuel gas tank is provided with a sensor incorporated in the supply line for detecting the temperature of the fuel gas, and the sensor and / or the holder housing the sensor form a stagnation point in the supply line, and the measurement area of the sensor is arranged within the area of the stagnation point. That is, the temperature of the fuel gas within the area of the stagnation point is measured, and as a result, the total temperature can be detected by the sensor.

[0020] The proposed fuel gas tank can, therefore, be used to implement the method according to the present invention described above. With the fuel gas tank, therefore, the same advantages as those achieved by the method according to the present invention described above can be achieved.

[0021] Preferably, the sensor and / or the holder has a spray surface, and the spray surface is oriented substantially perpendicular to the flow direction of the fuel gas in the supply line when filling the storage volume with fuel gas. During filling, therefore, the fuel gas is blocked at the spray surface, and as a result, the spray surface of the sensor and / or the holder forms a stagnation point. To detect the temperature of the fuel gas within the area of the stagnation point, preferably, the spray surface of the sensor simultaneously forms the measurement area of the sensor.

[0022] In a development of the present invention, outside the area of the stagnation point, another sensor is incorporated in the supply line or in the storage volume. With the said another sensor, based on the positioning outside the area of the stagnation point, the static temperature within the fuel gas tank is detected. From the total temperature measured by the first sensor and the static temperature measured by the said another sensor, an average value and / or a difference value can be formed. The average value provides information about the average temperature within the fuel gas tank required for calculating the stored mass. From the difference value, the flow velocity of the fuel gas in the filling direction can be estimated.

[0023] When incorporating the above-mentioned other sensor into the supply path, the above-mentioned other sensor is preferably arranged or oriented such that the fuel gas is guided to pass along the sensor, rather than being directly impinged by the fuel gas. This is because, unlike the first sensor, it is important to avoid the formation of stagnation points within the area of the above-mentioned other sensor. For this purpose, this sensor can be arranged substantially parallel to the flow direction of the fuel gas. Alternatively, the above-mentioned other sensor can be arranged not only outside the area of the stagnation point but also outside the supply path, as a result, ensuring that the static temperature is more strongly considered.

[0024] According to a further proposal, both sensors are coupled via a holder. The holder thereby facilitates the assembly of the sensors.

[0025] More preferably, the supply path is guided, at least in part, via a pipe that penetrates into the storage volume. The pipe predetermines the filling direction. Further, the pipe has a defined flow cross-section, and the flow cross-section simplifies the formation of stagnation points by the first sensor and / or the holder. The first sensor and / or the holder are incorporated into the pipe for this purpose, specifically, preferably, incorporated such that the impingement surface is oriented perpendicular to the flow direction of the fuel gas in the filling direction.

[0026] Advantageously, the supply line, the tank valve and at least one sensor form a tank unit, which is inserted, preferably centrally arranged, into an opening in the end face of the wall surrounding the storage volume, in particular screwed in. As a tank unit, all components can be pre-assembled and inserted into the fuel gas tank as a pre-assembled structural unit, as a result of which the assembly is simplified. At the same time, the installation space can be saved. The tank unit may further accommodate another component, for example another valve and / or another sensor. Furthermore, the tank unit may have a pipe protruding into the storage volume, through which the supply line is guided in at least some sections, in particular the end section of the supply line.

[0027] Furthermore, a fuel gas tank system comprising at least one fuel gas tank according to the present invention is proposed. For example, a plurality of identical fuel gas tanks may be connected via a common frame in a parallel arrangement. The frame facilitates the assembly of the fuel gas tank system in a vehicle, for example in a fuel cell vehicle.

[0028] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

Brief Description of the Drawings

[0029]

Figure 1

Figure 2a)

Figure 2b)

Figure 2c)

Figure 2d)

Figure 3

Figure 4

DETAILED DESCRIPTION OF THE INVENTION

[0030] The fuel gas tank 1 shown in FIG. 1 includes a wall 12 surrounding the storage volume 2. The wall 12 has an opening 13 at the end face, and a tank unit 11 is inserted into the opening 13. A supply path 3 having an incorporated tank valve 4 extends through the tank unit 11 to fill the fuel gas tank 1 with fresh fuel gas. One end section of the supply path 3 is defined by a pipe 10 that penetrates into the storage volume 2. Since the fuel gas, for example hydrogen, is strongly heated when introduced into the storage volume 2, the temperature of the fuel gas is monitored by sensors 5 and 6. The first sensor 5 is used to detect the total temperature at that time, and the second sensor 6 is used to detect the static temperature.

[0031] To detect the total temperature, that is, the maximum temperature occurring locally, the first sensor 5 lies across the supply path 3 and is incorporated into the pipe 10 so as to be directly blown by the fuel gas in the filling direction. At the impingement surface 9 of the sensor 5 that is oriented perpendicular to the flow direction of the fuel gas, the fuel gas is blocked, and as a result, a stagnation point 7 is formed on the impingement surface 9. The second sensor 6 for detecting the static temperature is also incorporated into the pipe 10 but is oriented so as not to be directly blown in the filling direction. That is, no stagnation point is formed by the second sensor 6, and the fuel gas can flow past without being obstructed.

[0032] Of the two sensors 5, 6, at least one of the sensors 5, 6 may be attached to the pipe 10 indirectly via the holder 8. This can be said especially about the first sensor 5. This is because the holder 8 enables the sensor 5 to be arranged as centrally as possible with respect to the supply path 3, and as a result, the sensor 5 is well sprayed. Depending on the configuration of the holder 8, the second sensor 6 can also be incorporated into the holder 8. The embodiments can be seen in FIGS. 2a) to 2d). These show that the second sensor 6 is arranged downstream of the first sensor 5 in the flow direction of the fuel gas, specifically at an angle, particularly at a right angle, so that the fuel gas can flow through without being obstructed. For flow optimization in the supply path 3, the holder 8 may have an outer contour that tapers in the filling direction, for example, a conical shape that tapers upstream of the second sensor 6. When the flow direction of the fuel gas in the supply path 3 is reversed, the fuel gas simultaneously flows over the first sensor 5 via the outer contour of the holder 8, and as a result, it is ensured that the first sensor 5 also only detects the static temperature.

[0033] The first sensor 5 is preferably incorporated into the holder 8 such that the spraying surface 9 of the sensor 5 simultaneously forms the spraying surface 9 of the holder 8. The spraying surface 9 may be configured flat as shown in FIGS. 2a) and 2b). However, the spraying surface 9 may be convexly shaped as shown in FIG. 2c) or concavely shaped as shown in FIG. 2d). Flow optimization can also be achieved through the shape of the spraying surface 9.

[0034] In FIG. 3, another holder 8 having a sensor 5 for detecting the entire temperature can be seen. The holder 8 is incorporated in the pipe 10 and extends perpendicular to the flow direction 15 of the fuel gas. As shown in FIG. 3, the connection line 14 can be guided to the sensor 5 through the holder 8 to simultaneously realize the necessary electrical connection of the sensor 5. The second sensor 6 for detecting the static temperature is incorporated in the inner surface of the pipe 10, and as a result, the flow cross-section is not restricted by the second sensor 6. The fuel gas flow thereby passes along the second sensor 6. The connection line 14 of the second sensor 6 is guided to the outside through the holder 8.

[0035] The embodiment of FIG. 4 differs from the embodiment of FIG. 3 only in that the second sensor 6 is incorporated in the outer surface of the pipe 10, and as a result, the static temperature of the fuel gas in the storage volume 2 is detected by the second sensor 6. In addition, the connection line 14 is guided to the outside through the holder 8.

Explanation of reference numerals

[0036] 1 Fuel gas tank 2 Storage volume 3 Supply path 4 Tank valve 5 First sensor 6 Second sensor 7 Stagnation point 8 Holder 9 Spraying surface 10 Pipe 11 Tank unit 12 Wall 13 Opening 14 Connection line 15 Flow direction

Claims

1. A method for filling a storage volume (2) of a fuel gas tank (1) with fuel gas, comprising: introducing the fuel gas into the storage volume (2) via a supply line (3) having an integrated tank valve (4), and detecting the temperature of the fuel gas in the region of a stagnation point (7) formed by the sensor (5) and / or a holder (8) accommodating the sensor (5) within the supply line (3), said sensor (5) being integrated within the supply line (3). A method for filling a storage volume (2) of a fuel gas tank (1) with fuel gas.

2. comparing a measured value of the sensor (5) with a pre-determined temperature limit value, and halting or interrupting the filling process when the temperature limit value is exceeded. The method according to claim 1, characterized in that.

3. detecting, by means of another sensor (6), the temperature of the fuel gas outside the region of the stagnation point (7), for example within the storage volume (2), and determining an average value and / or a difference value from the measured values of both sensors (5, 6). The method according to claim 1 or 2, characterized in that.

4. The method according to claim 3, characterized in that the flow rate of the fuel gas is derived from the difference value.

5. A fuel gas tank (1) for a fuel gas tank system, comprising: a storage volume (2) fillable with fuel gas via a supply line (3) having an integrated tank valve (4), and further a sensor (5) integrated within the supply line (3) for detecting the temperature of the fuel gas, wherein the sensor (5) and / or a holder (8) accommodating the sensor (5) forms a stagnation point (7) within the supply line (3), and a measurement region of the sensor (5) is arranged within the region of the stagnation point (7). A fuel gas tank (1) for a fuel gas tank system.

6. The fuel gas tank (1) according to claim 5, characterized in that the sensor (5) and / or the holder (8) has a spraying surface (9), which is oriented substantially perpendicular to the flow direction (15) of the fuel gas within the supply line (3) when filling the storage volume (2) with fuel gas.

7. The fuel gas tank (1) according to claim 5 or 6, characterized in that another sensor (6) is integrated within the supply line (3) or within the storage volume (2) outside the region of the stagnation point (7).

8. The fuel gas tank (1) according to any one of claims 5 to 7, characterized in that the supply line (3) is guided, at least in part, via a pipe (10) that penetrates into the storage volume (2).

9. The supply line (3), the tank valve (4) and at least one of the sensors (5, 6) form a tank unit (11), and the tank unit (11) is inserted into an opening (13) in an end face, preferably arranged centrally, of a wall (12) surrounding the storage volume (2), in particular screwed in, of the fuel gas tank (1) according to any one of claims 5 to 8.

10. A fuel gas tank system comprising at least one fuel gas tank (1) according to any one of claims 5 to 9.

Images