METHOD FOR REFUELLING A MEANS OF TRANSPORT USING A HYDROGEN REFUELLING DEVICE

Description

[0001] The present invention relates to a method for refueling a means of transport by a hydrogen refueling device and a system for refueling a means of transport by a hydrogen refueling device. State of the art

[0002] The state of the art for refueling vehicles equipped with a hydrogen tank with hydrogen is described, among other things, in SAE J2601. This standard specifies, for example, that if communication occurs between the vehicle and a refueling device, the vehicle transmits a table once before the refueling process. This table contains a target pressure for the refueling process depending on the ambient temperature and the initial pressure in the hydrogen tank before the refueling process. The refueling device can, for example, use this table to determine and execute a refueling plan. The sensors arranged in a fuel cell system or peripherals are subject to manufacturing or service life-related tolerances. In complex systems, such as a fuel cell system, an unfavorable tolerance chain can lead to functional defects.The document US 2020 / 411886 A1 shows a refueling method according to the prior art and discloses that the refueling device stores the measured values ​​of pressure sensors of different vehicles during refueling in order to compare them with the measured values ​​of the pressure sensors of the refueling device. Disclosure of the invention

[0003] In vehicles powered by hydrogen, for example using a fuel cell system, a precise pressure sensor for detecting the pressure in a hydrogen tank would be useful to reduce the tolerance chain.

[0004] It is an object of the invention to provide a method that improves the accuracy of such a pressure sensor.

[0005] The object is achieved by a method for refueling a vehicle using a hydrogen refueling device. Advantageous embodiments and further developments can be found in the dependent claims and the following description.

[0006] A method for refueling a vehicle by means of a hydrogen refueling device is proposed, comprising the steps of establishing a communication connection between the hydrogen refueling device and the vehicle, coupling a hydrogen dispensing device to a tank of the vehicle and refueling the vehicle, detecting a first hydrogen pressure of a hydrogen flow delivered by the hydrogen dispensing device in the refueling device during refueling, detecting a second hydrogen pressure of the received hydrogen flow and / or the tank in the vehicle during refueling, determining a deviation between the first hydrogen pressure and the second hydrogen pressure, and changing a sensor characteristic curve in the vehicle to correct the detection of the second hydrogen pressure if the deviation exceeds a threshold value.

[0007] Establishing a communication connection can, for example, involve connecting the vehicle to the hydrogen refueling facility via a wireless network or other radio connection. It is conceivable that the hydrogen refueling facility has or is coupled to an infrastructure that allows a data connection between the vehicle and the hydrogen refueling facility. Of particular importance are wireless connections that prevent contact between the hydrogen refueling facility and the vehicle. Metallic contacts, in particular, should be avoided, as these pose a risk of explosion if sparks occur near hydrogen-carrying facilities. The communication connection is preferably bidirectional, so that data and parameters can be transmitted in both directions during the refueling process.

[0008] Coupling a hydrogen dispensing device to a tank may involve opening a tank cap and connecting a fuel nozzle. It is conceivable that the data connection is established when the tank cap is opened and / or the fuel nozzle is inserted. Alternatively, however, it may already be established at that time.

[0009] Fuel cell systems can have at least one second pressure sensor in the high-pressure area, for example on or near the tank. During refueling, a control unit coupled to the second pressure sensor can communicate with the refueling device. Since the refueling device measures the pressure during refueling, this value can be exchanged and compared with the pressure measurement on the vehicle side. This could allow an excessive deviation in a pressure measurement to be corrected by the second pressure sensor in such a way that a correction value, a correction term, or several correction values ​​are stored in the relevant second pressure sensor or the control unit and taken into account when outputting the second hydrogen pressure. This consequently adjusts the sensor characteristic curve and generates more precise measured values.

[0010] It is conceivable to perform this process once or multiple times during each refueling process. For multiple refueling, different variants could be considered, which are described below. In addition to reducing the tolerance chain in the control of fuel cell systems, maintenance costs can also be reduced. In principle, sensors used could be implemented more cost-effectively, as they can be calibrated or adjusted during refueling processes. The drift of sensor signals over their lifetime can be compensated for by the method according to the invention.

[0011] In an advantageous embodiment, the first and second hydrogen pressures are recorded once after refueling has begun. Determining the deviation and, if necessary, changing the sensor characteristic curve could occur at the beginning of the refueling process. After a stable hydrogen flow has been established, the hydrogen pressure could be recorded in the refueling device and the vehicle. However, it is also conceivable that the deviation is only recorded after a certain time, after a stable hydrogen flow has been delivered for a predetermined period. This method step could also be performed shortly before the end of the refueling process.

[0012] However, it is preferable to record the first and second hydrogen pressures and determine the deviation several times. For example, several hydrogen pressure values ​​could be recorded at different times and then compared with each other. This would allow individual measurements to be supported and subjected to a plausibility check. The mutual recording of the hydrogen pressures does not necessarily have to be completely synchronized. It is conceivable that hydrogen pressures are recorded in the refueling facility and in the vehicle according to a predetermined pattern and stored with a time stamp, which are then subsequently compared. They can be transmitted or recorded successively or simultaneously in order to compare them ad hoc or collectively after the refueling process. The time stamps linked to the individual measured values ​​allow the individual measured values ​​recorded by both sides to be assigned.

[0013] The determination of the deviation and / or the recording of the first and second hydrogen pressures could be repeated, for example, after a predetermined waiting time. In particular, the recording of the hydrogen pressures could be performed at regular or irregular time intervals or according to a predetermined temporal pattern.

[0014] Determining the deviation and / or recording the first and second hydrogen pressures could also be repeated after passing through a predetermined pressure change. During refueling, several pressure levels could be passed through, which could be specified, for example, in a refueling plan. Upon reaching certain pressure levels, the hydrogen pressures could be recorded on both sides, with one or more of the measured values ​​being compared with each other.

[0015] Particularly advantageously, the second hydrogen pressure is transmitted from the vehicle to the refueling device, with the refueling device determining the deviation. It can be assumed that the pressure sensor in the refueling device is more accurate than the pressure sensor in the vehicle, since the refueling device carries out precise control of a refueling process. The detection of the first hydrogen pressure could therefore already be carried out continuously during the refueling process, so that recording the second hydrogen pressure and the comparison only requires a minor modification of a software program in the refueling device and the necessary resources could already be available. If an intolerable deviation in the hydrogen pressures is detected, the refueling device could send a corresponding signal to the vehicle, which could then be implemented on-board.

[0016] Alternatively, the vehicle could of course also be configured to detect the deviation. The refueling device can transmit the recorded initial hydrogen pressure values ​​to the vehicle, where the deviation is then determined to adjust the sensor characteristic curve.

[0017] In an advantageous embodiment, the method comprises issuing a warning signal if the deviation exceeds a second threshold that is higher than the first threshold. The second threshold could be defined such that exceeding it would be interpreted as a sensor defect. The warning signal can therefore be understood as a maintenance notification that is transmitted to the vehicle and processed there in a predetermined manner. It may be expedient to continue the refueling process after issuing a warning signal in such a way that a safe operating mode is adopted.

[0018] It is particularly advantageous if the deviation is determined and the sensor characteristic curve is changed after the refueling process. This allows multiple hydrogen pressures to be recorded and compared, from which different deviations and more comprehensive change parameters can be determined. As a final step, at the end of or after the refueling process, the sensor characteristic curve could be adjusted.

[0019] The method may further comprise the step of calculating or estimating a pressure loss between the refueling device and the vehicle, i.e., the tank located therein. The pressure loss could be modeled or stored in the second control unit, or determined or transmitted by the refueling device at the beginning of the refueling.

[0020] The vehicle and / or the refueling device could be configured to perform the process during each refueling operation. A sensor characteristic curve in the vehicle is then constantly adapted.

[0021] Analogously, the invention further relates to a system for refueling a means of transport with hydrogen, comprising a refueling device with a hydrogen dispensing device, a first connection unit, a first pressure sensor and a first control unit, a second connection unit and a second control unit for integration into a means of transport, wherein the first pressure sensor is coupled to the first control unit and is designed to detect a first hydrogen pressure of a hydrogen flow delivered by the hydrogen dispensing device, wherein the second control unit is designed to record a second hydrogen pressure of the hydrogen flow and / or of a tank in the means of transport detected by a second pressure sensor in the means of transport, and wherein one of the first control unit and the second control unit is designed toto determine a deviation between the first hydrogen pressure and the second hydrogen pressure and to change a sensor characteristic in the vehicle to correct the detection of the second hydrogen pressure if the deviation exceeds a first threshold value.

[0022] Furthermore, one of the first control unit and the second control unit may be configured to output a warning signal if the deviation exceeds a second threshold value that is higher than the first threshold value.

[0023] The system or the components contained therein are furthermore designed to carry out one, several or any of the method steps described above.

[0024] Further measures improving the invention are presented in more detail below together with the description of the preferred embodiments of the invention with reference to figures. Examples of implementation

[0025] It shows: Figure 1 a schematic representation of the system for refueling a vehicle. Figure 2 a schematic representation of the method according to the invention for refueling a means of transport.

[0026] Figure 1 schematically shows a system 2 for refueling a means of transport 4. In the case shown, the means of transport 4 is, for example, a bus in which hydrogen is used via a fuel cell (not shown) to generate electrical power. The system 2 comprises a hydrogen refueling device 6 having a fuel nozzle 8 as a hydrogen dispensing device. This can be coupled to the means of transport 4 in order to establish a fluid connection with a tank 10 inside the means of transport 4. The hydrogen refueling device 6 further comprises a first control unit 12, which is connected to a first connection unit 14.

[0027] The first connection unit 14 is capable of communicating with a second connection unit 16 of the vehicle 4. This can be done either directly, i.e., as a point-to-point connection, or via a corresponding infrastructure. The second connection unit 16 is coupled to a second control unit 18. Consequently, the first control unit 12 and the second control unit 18 can communicate with each other.

[0028] The refueling device 6 has a first pressure sensor 20, which is coupled to the first control unit 12 and is designed to detect a first hydrogen pressure of a hydrogen mass flow that is fed into the fueling nozzle 8. A corresponding second pressure sensor 22 is provided in the vehicle 4, which is coupled to the tank 10 and the second control unit 18 and is designed to detect a second hydrogen pressure. This second hydrogen pressure increases during refueling by the refueling device 6. Due to the pressure equilibrium, the first hydrogen pressure corresponds to the second hydrogen pressure. Consequently, ideally, the measured values ​​of the first pressure sensor 20 and the second pressure sensor 22 are identical. Due to aging and wear, the second pressure sensor 22 in particular can become increasingly imprecise.One of the first control unit 12 and the second control unit 18 is configured to determine a deviation between the first hydrogen pressure and the second hydrogen pressure and to modify a sensor characteristic curve in the vehicle 4 to correct the detection of the second hydrogen pressure if the deviation exceeds a first threshold value. This improves the precision of the second pressure sensor 22 and compensates for sensor errors. Furthermore, one of the first control unit 12 and the second control unit 18 can be configured to output a warning signal if the deviation exceeds a second threshold value that is higher than the first threshold value. This is particularly useful in the case of extreme deviations.

[0029] Fig. 2shows a method for refueling the vehicle 4 using the hydrogen refueling device 6. The method comprises the steps of establishing 24 a communication connection between the hydrogen refueling device 6 and the vehicle 4, coupling 26 the hydrogen dispensing device 8 to the tank 10 of the vehicle 4, and refueling 28 the vehicle. During refueling, a first hydrogen pressure of a hydrogen stream dispensed by the hydrogen dispensing device 8 is detected 30 in the refueling device 6. Simultaneously, before, or afterward, a second hydrogen pressure is detected 32 in the vehicle. A deviation between the first hydrogen pressure and the second hydrogen pressure is determined 34. If the deviation exceeds a first threshold value, a sensor characteristic curve in the vehicle 4 is modified 36 to correct the detection of the second hydrogen pressure.If the deviation exceeds a second threshold, a warning signal is also issued 38. The second threshold exceeds the first threshold and could, for example, be twice as large, three times as large or larger.

[0030] The recording 30 or 32 can be performed multiple times. The recorded second hydrogen pressures can also be transmitted 40 to the refueling device 6 in order to determine the deviation there. It is conceivable to record the hydrogen pressures independently of one another and multiple times, for example at specific time intervals, after passing through specific pressure stages, or in other patterns. The second hydrogen pressure values ​​can be transmitted to the refueling device 6 directly after each recording or collected after the refueling process. To clearly identify the respective recording time, the individual hydrogen pressure values ​​are each provided with a time stamp, for example. The first hydrogen pressure values ​​recorded in the refueling device 6 can also be provided with time stamps.When measuring synchronously or when passing through discrete pressure levels during refueling, the individual pressure values ​​can be compared with each other.

Claims

1. Method for fuelling a means of transport (4) by means of a hydrogen fuelling device (6), having the steps of: - establishing (24) a communication connection between the hydrogen fuelling device (6) and the means of transport (4), - coupling (26) a hydrogen delivery device (8) to a tank (10) of the means of transport (4) and fuelling the means of transport (4), - sensing (30) a first hydrogen pressure of a hydrogen stream delivered by the hydrogen delivery device (8) in the fuelling device (6) during fuelling (28), - sensing (32) a second hydrogen pressure of the received hydrogen stream and / or of the tank (10) in the means of transport (4) during fuelling (28), - determining (34) a deviation between the first hydrogen pressure and the second hydrogen pressure, and - changing (36) a sensor characteristic curve in the means of transport (4) in order to correct the sensing of the second hydrogen pressure if the deviation exceeds a first threshold value.

2. Method according to Claim 1, wherein the first and second hydrogen pressure is sensed (30, 32) once after fuelling (28) has been started.

3. Method according to Claim 1, wherein the first and second hydrogen pressure is sensed (30, 32) multiple times and the deviation is determined (34) multiple times.

4. Method according to Claim 3, wherein the determination (34) of the deviation and / or the sensing (30, 32) of the first and second hydrogen pressure is / are repeated after a predetermined waiting time has elapsed.

5. Method according to Claim 3 or 4, wherein the determination (34) of the deviation is repeated after passing through a predetermined pressure change level.

6. Method according to one of the preceding claims, wherein the second hydrogen pressure is transmitted from the means of transport (4) to the fuelling device (6), and the fuelling device (6) determines (34) the deviation.

7. Method according to one of the preceding claims, further comprising - outputting (38) a warning signal if the deviation exceeds a second threshold value that is higher than the first threshold value.

8. Method according to one of the preceding claims, wherein the deviation is determined (34) and the sensor characteristic curve is changed (36) after the fuelling process.

9. System (2) for fuelling a means of transport with hydrogen, having: - a fuelling device (6) comprising a hydrogen delivery device (8), a first connection unit (14), a first pressure sensor (20) and a first control unit (12), - a second connection unit (16) and a second control unit (18) for integration into a means of transport (4), wherein the first pressure sensor (20) is coupled to the first control unit (12) and is designed to sense a first hydrogen pressure of a hydrogen stream delivered by the hydrogen delivery device (8), wherein the second control unit (18) is designed to receive, in the means of transport (4), a second hydrogen pressure of the hydrogen stream or of a tank (10) that is sensed by a second pressure sensor (22) in the means of transport (4), and wherein one of the first control unit (12) and the second control unit (18) is designed to determine a deviation between the first hydrogen pressure and the second hydrogen pressure and to change a sensor characteristic curve in the means of transport (4) in order to correct the sensing of the second hydrogen pressure if the deviation exceeds a first threshold value.

10. System (2) according to Claim 9, wherein the one of the first control unit (12) and the second control unit (18) is designed to output a warning signal if the deviation exceeds a second threshold value which is higher than the first threshold value.