Method for operating fuel gas tank system, control device

Abstract

The invention relates to a method for operating a fuel gas tank system (1) having a plurality of fuel gas tanks (2) connected in parallel for storing a fuel gas, preferably hydrogen, in order to avoid local icing during the extraction of the fuel gas from one fuel gas tank (2). According to the invention, the temperature in the fuel gas tank (2) and / or in an extraction path (4) connected thereto, in particular in the region of at least one functionally dependent component (3), is monitored, and when a predefined lower temperature extreme value (Tref) is exceeded, (a) extraction from the fuel gas tank (2) is stopped and a switch is made to another fuel gas tank (2), and / or (b) the extraction path (4) and / or the at least one functionally dependent component (3) is supplied with heat in a targeted manner. The invention also relates to a controller for carrying out the steps of the method.

Description

Technical Field

[0001] This invention relates to a method for operating a fuel gas tank system. Furthermore, the invention also relates to a controller for performing the steps of this method.

[0002] Preferred applications are for mobile fuel gas tank systems in fuel cell vehicles and / or fuel gas vehicles, such as vehicles with hydrogen internal combustion engines. The fuel gas can be, in particular, hydrogen or natural gas, stored at high pressure in multiple parallel-connected fuel gas tanks within the fuel gas tank system. The storage pressure is typically 700 to 350 bar for hydrogen. Background Technology

[0003] When fuel gas, such as hydrogen, is drawn from the fuel gas tank of a fuel gas tank system, a temperature drop occurs within the fuel gas tank and the valves involved. Furthermore, the temperature within the fuel gas tank is affected by other factors, particularly by heat transfer processes on the outer wall of the fuel gas tank and on the installed accessories. Here, the magnitude of the current flow velocity plays a significant role. In large agricultural machinery, due to low travel speeds and installation conditions, small flow around the fuel gas tank is typically observed.

[0004] During the operation of a fuel gas tank system, moisture may accumulate inside the tank. This moisture, whether liquid or gaseous, can be carried out with the mass flow of fuel gas during extraction and deposited along the extraction path on the inner surface and surrounding accessories. If the temperature drops further due to continuous fuel gas extraction, falling below the freezing point of water, localized icing may occur. This localized icing can then lead to changes in the flow cross-section and / or damage to functionally relevant components. Summary of the Invention

[0005] Therefore, the objective of this invention is to prevent icing of functionally relevant components in a fuel gas tank system having multiple fuel gas tanks.

[0006] To address this task, a method having the features of claim 1 is proposed. Advantageous extensions of the invention can be derived from the dependent claims. Furthermore, a controller for performing the steps of the method according to the invention is also provided.

[0007] This invention proposes a method for operating a fuel gas tank system having multiple fuel gas tanks connected in parallel for storing fuel gas, preferably hydrogen. In this method, to prevent localized icing during fuel gas extraction from the fuel gas tanks, the temperature is monitored within the fuel gas tanks and / or in the extraction path connected to the fuel gas tanks, particularly in the area containing at least one functionally relevant component. Furthermore, when the temperature is below a predetermined lower temperature extreme value T_ref,

[0008] (a) Stop drawing from the fuel gas tank and switch to another fuel gas tank; and / or

[0009] (b) To supply heat to the extraction path and / or at least one functionally relevant component in a targeted manner.

[0010] Switching to another fuel gas tank when the temperature drops below the lower temperature extreme T_ref prevents further cooling caused by the gas mass flow, thus preventing icing in the extraction path. Alternatively or supplementarily, icing in the extraction path can be prevented by selectively supplying heat.

[0011] Preferably, the two measures are combined so that after switching to another fuel gas tank, heat is selectively supplied to the extraction path connected to the first fuel gas tank to raise the temperature back above T_ref as quickly as possible. This is because if the temperature in the other fuel gas tank or in the extraction path connected to it also drops below the lower temperature extreme T_ref within a short period, another switchover may be necessary. Then, the first fuel gas tank will be put back into service.

[0012] The lower temperature extreme value T_ref is preferably chosen in such a way that there is no risk of icing even when the temperature extreme value is reached. This ensures that the flow passage cross section is not blocked by icing and that the function of at least one functionally relevant component is guaranteed.

[0013] To keep additional energy demands as low as possible, an extension of the invention proposes that, in step (b), heat supply be terminated when the temperature rise x [K] exceeds a lower temperature limit (T_ref). For this purpose, an upper temperature limit can be pre-defined. If the temperature in the fuel gas tank and / or in the extraction path exceeds this limit, targeted heat supply is terminated.

[0014] Advantageously, in step (b), heat is generated by means of electric heating devices and / or electric heating elements. These electric heating devices and / or electric heating elements can be selectively manipulated to generate heat, and furthermore, they can be integrated into the fuel gas tank system in a space-saving manner. The electric heating devices and / or electric heating elements are preferably arranged on the extraction path and / or on at least one functionally related component.

[0015] Furthermore, temperature monitoring is preferably performed using at least one temperature sensor disposed on the fuel gas tank, the extraction path, and / or at least one functional component. Ideally, the temperature is monitored at multiple defined locations within the fuel gas tank system, i.e., at least one temperature sensor is present at each of these locations.

[0016] Using multiple temperature sensors, it is preferable to monitor the temperature in all fuel gas tanks and / or all extraction paths, rather than just in one fuel gas tank and / or one extraction path. To enable temperature comparison, the temperature sensors should be positioned at the same locations on the fuel gas tanks and / or along the extraction paths.

[0017] It is preferable to monitor the temperature in the area where at least one tank valve of the fuel gas tank is located. A tank valve is typically not a single valve, but a valve assembly that integrates multiple valves and other safety devices within its housing. Therefore, a tank valve comprises multiple functionally related components. Consequently, temperature monitoring can be performed with fewer temperature sensors and thus more efficiently. Since each fuel gas tank in a storage tank system typically has its own tank valve, it is preferable to monitor the temperature in the areas where all tank valves of the fuel gas tank system are located.

[0018] Furthermore, preferably, in step (b), heat is supplied selectively to the area where at least one tank valve of the fuel gas tank is located. Because tank valves typically include multiple function-related components, the number of electric heating devices and / or electric heating elements can be reduced, making the targeted heat supply more efficient.

[0019] To address the task described at the outset, the present invention also proposes a controller for a fuel gas tank system. This controller is configured to perform the steps of the method according to the present invention.

[0020] For example, a controller can analyze and evaluate sensor data from at least one temperature sensor to monitor the temperature in the fuel gas tank and / or in the extraction path connected to that fuel gas tank. Based on the analysis and evaluation results, the controller can then switch from one fuel gas tank to another during fuel gas extraction. For this purpose, a pre-defined lower temperature extreme value T_ref is preferably stored in the controller. If temperature data for all fuel gas tanks and / or all extraction paths are available in the controller, the controller can identify the hottest fuel gas tank or extraction path as needed, allowing switching to that tank or path. Therefore, the controller can determine the order of fuel gas tanks during fuel gas extraction, and in particular, the operating sequence of the tank valves connected to the fuel gas tanks. Attached Figure Description

[0021] The method according to the invention and its advantages are described in detail below with reference to the accompanying drawings. The drawings show:

[0022] Figure 1 : A schematic diagram of a fuel gas tank system capable of operating according to the method of the present invention;

[0023] Figure 2: A graph used to show the trend of tank temperature under conditions of continuous fuel gas extraction and constant ambient temperature;

[0024] Figure 3 : A graph used to show the trend of tank temperature under conditions of continuous fuel gas extraction and ambient temperature variation due to different vehicle speeds.

[0025] Figure 4 The possible operating sequence of tank valves and heating devices. Detailed Implementation

[0026] from Figure 1 A simplified schematic diagram of the fuel gas tank system 1, which has multiple fuel gas tanks 2, can be seen. The fuel gas tank system 1 shown is currently used to supply fuel gas, preferably hydrogen, to the fuel cell stack 7. Alternatively, hydrogen can also be supplied to a hydrogen internal combustion engine via the fuel gas tank system 1.

[0027] Each fuel gas tank 2 is connected to a tank valve 6, and at least one functionally related component 3, particularly a valve, is integrated into the tank valve for drawing fuel gas from the fuel gas tank 2. Therefore, the drawing path 4 passes through the tank valve 6, and the drawing paths 4 of multiple fuel gas tanks 2 converge sequentially. Temperature sensors 5 are also integrated into the tank valves 6 of the fuel gas tank system 1 shown, by means of which the temperature in the corresponding fuel gas tank 2 is monitored.

[0028] As in Figure 2 As exemplarily shown, the temperature inside fuel gas tank 2 decreases when fuel gas is drawn from fuel gas tank 2. This is regardless of the initial temperatures (initial temperatures at...). Figure 2 The temperatures are 20°C, 0°C, -10°C, and -25°C respectively. After a given time period, the temperature drops by approximately 35K. This means that the temperature drops below the freezing point of water, causing moisture carried out with the gas flow during fuel gas extraction to potentially deposit and freeze on the inner surface of the extraction path 4. If this occurs in the area where component 3 is located, the function of component 3 is no longer guaranteed.

[0029] Ambient temperature also affects the temperature inside fuel gas tank 2; for vehicles, this ambient temperature is particularly affected by vehicle speed. This relationship can be seen from... Figure 3 This can be seen from the text.

[0030] The method of this invention avoids icing in the extraction path during fuel gas extraction from fuel gas tank 2. For this purpose, the temperature in fuel gas tank 2 or in tank valve 6 is detected by temperature sensor 5. If the temperature in the fuel gas tank drops below a predetermined lower temperature limit T_ref due to fuel gas extraction, extraction from that fuel gas tank 2 is stopped, and the tank valve 6 of another fuel gas tank 2 whose temperature exceeds the lower temperature limit T_ref is operated. That is, the process switches to another fuel gas tank 2 and fuel gas is now extracted from that fuel gas tank 2.

[0031] Figure 4 The example illustrates the operating sequence of three tank valves 6.1, 6.2, and 6.3, which are operated alternately. Figure 4 The circular symbols in the first three lines indicate that the corresponding tank valve or the extraction path passing through the tank valve is in the open state, and the horizontal symbols indicate that the corresponding tank valve or the corresponding extraction path is in the closed state.

[0032] The next three lines represent the temperatures in the fuel gas tank connected to the tank valve, as measured by a temperature sensor. If the temperature is higher than T_ref, the tank valve is open; if the temperature is lower than T_ref, the tank valve is closed.

[0033] The last three lines indicate the status of the heating devices connected to the tank valve, which can be used to supply heat to the tank valve in a targeted manner. If the temperature is below T_ref, the heating device is activated (circle symbol), and heat is supplied to the tank valve in a targeted manner; if the temperature is above T_ref, the heating device is deactivated (horizontal line symbol).

Claims

1. A method for operating a fuel gas tank system (1), the fuel gas tank system having a plurality of fuel gas tanks (2) connected in parallel for storing fuel gas, preferably hydrogen, wherein, To avoid localized icing during fuel gas extraction from a fuel gas tank (2), the temperature is monitored in the fuel gas tank (2) and / or in the extraction path (4) connected to the fuel gas tank (2), particularly in the area containing at least one functionally related component (3), and when below a predetermined lower temperature extreme (T_ref), (a) Stop drawing from the fuel gas tank (2) and switch to another fuel gas tank (2), and / or (b) To supply heat to the extraction path (4) and / or at least one functionally related component (3) in a targeted manner.

2. The method according to claim 1, Its features are, In step (b), the heat supply is terminated when the temperature x[K] rises above the lower temperature extreme value (T_ref).

3. The method according to claim 1 or 2, Its features are, In step (b), heat is generated by means of an electric heating device and / or an electric heating element, which is preferably arranged on the extraction path (4) and / or on the at least one functionally related component (3).

4. The method according to any one of the preceding claims, Its features are, Temperature monitoring is performed using at least one temperature sensor (5) arranged on the fuel gas tank (2), the extraction path (4), and / or the at least one functional component (3).

5. The method according to any one of the preceding claims, Its features are, The temperature in the area where at least one valve (6) of the fuel gas tank (2) is located is monitored.

6. The method according to any one of the preceding claims, Its features are, In step (b), heat is supplied selectively to the area where at least one valve (6) of the fuel gas tank (2) is located.

7. A controller for a fuel gas tank system (1), the controller being configured to perform the steps of the method according to any one of the preceding claims.

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