METHOD AND SYSTEM FOR OPERATING A MOTOR VEHICLE FUEL CELL

Abstract

The present development relates to a system and a method for operating a fuel cell (10) of a motor vehicle (1), the method comprising the following steps: - activating a delay mode of the fuel cell (10) by means of an operating element (26) by a user, and - Delaying the initiation of a shutdown procedure of the fuel cell (10) and continuing operation of the fuel cell (10) with the delay mode activated.

Description

Technical area

[0001] The present development relates to a method and a system for operating a motor vehicle fuel cell. Furthermore, the present development relates to a fuel cell motor vehicle equipped with such a system. background

[0002] Fuel cell-powered vehicles typically operate in hybrid mode. In addition to the fuel cell as a unit for generating electrical energy, such vehicles typically have a rechargeable battery that can be electrically coupled to the fuel cell. An electric drive can be powered by either the battery or the fuel cell. Depending on the battery's charge level, a fuel cell can typically be shut down for a certain period of time, particularly when there is insufficient free charging capacity on the battery side to absorb the electrical power generated by the fuel cell.

[0003] Activating and deactivating a fuel cell typically takes a certain amount of time. For example, certain sections of the fuel cell must be dehumidified and / or vented before shutdown. Furthermore, it may take some time until supply lines for the reaction gases are shut off and clear of reaction gas. Finally, fuel cells must operate within a specified temperature range, which requires cooling or heating.

[0004] If a fuel cell vehicle is operated in a start-stop mode in which the vehicle stops quite frequently or even switches off and is then switched on again within a relatively short time interval, a shutdown procedure intended for the fuel cell may not be fully complied with and may have to be interrupted by restarting the vehicle.

[0005] According to DE 10 2017 207 477 A1, for example, a method for operating a fuel cell system is provided, wherein a number and duration of shutdown and / or stop phases of the vehicle in a defined time interval in a first vehicle state or in a second vehicle state is determined using vehicle state-specific learning functions, and wherein operating parameters of the fuel cell system and at least one subsystem of the fuel cell system are set depending on the determined number and duration of the shutdown and / or stop phases of the vehicle.

[0006] In contrast, the present further development is based on the task of providing the end user of the motor vehicle with the most comprehensive possible control over the operation of the fuel cell, or rather the motor vehicle, using the simplest and most cost-effective means possible. Advantageous designs

[0007] This object is achieved by a method for operating a fuel cell, a system for controlling the operation of a fuel cell, and a computer program product according to the features of the independent patent claims. Advantageous embodiments of the present development are the subject of respective dependent patent claims.

[0008] In a first aspect, a method for operating a fuel cell of a motor vehicle is provided. The method comprises activating a delay mode of the fuel cell by means of a control element by a user. When the delay mode is activated, which can optionally be activated exclusively by means of the control element and / or exclusively by the user, a shutdown procedure of the fuel cell is initiated with a time delay, and consequently, the fuel cell continues to operate. While the initiation of the shutdown procedure of the fuel cell is delayed, the fuel cell continues to operate.

[0009] In this respect, the operator or user of the motor vehicle can determine for themselves whether the fuel cell should continue to operate in operating states of the motor vehicle in which the fuel cell would typically be switched off. Activation of the so-called delay mode, which can be initiated by the user, ensures that the motor vehicle's control unit(s) responsible for controlling the fuel cell or a system for controlling the operation of the fuel cell acts in such a way that the fuel cell continues to operate and is not switched off even when the motor vehicle or the operating state of the motor vehicle currently requires no or only a comparatively low amount of electrical power generation from the fuel cell.

[0010] This makes it possible, in particular, to ensure that the fuel cell continues to operate during comparatively short shutdown or stop phases of the motor vehicle, which would normally lead to the initiation of a fuel cell shutdown procedure. This avoids the need to interrupt an ongoing fuel cell shutdown procedure, namely when a fuel cell shutdown procedure was initiated as a result of a shutdown and / or stop phase of the motor vehicle, but this procedure must be interrupted due to a renewed power request to the fuel cell, for example, when the motor vehicle is restarted or after the motor vehicle has started moving.

[0011] By giving the user a direct option to activate the fuel cell's so-called deceleration mode via the control element, extremely simple control of the fuel cell is possible, which in particular contributes to avoiding unnecessary shutdown procedures. This can increase the service life of the fuel cell. Its maintenance requirements can also be reduced accordingly. Furthermore, avoiding a shutdown procedure can also have a positive impact on the vehicle's overall energy consumption.

[0012] According to a further development of the method, when the deceleration mode is activated, the fuel cell continues to operate after the motor vehicle is parked. When the motor vehicle is parked, it remains idle. At the very least, the motor vehicle's electric drive consumes no or only comparatively little electrical energy. When the motor vehicle is parked, and the associated comparatively low electrical energy consumption of the motor vehicle is achieved, a shutdown procedure for the fuel cell is normally initiated.

[0013] By activating the delay mode, this shutdown procedure is prevented or delayed, at least for a certain period of time. The delay of the shutdown procedure, which is to be implemented with this method, can depend on other parameters or operating conditions of the motor vehicle, or on the operating condition of its battery.

[0014] In deceleration mode, it can be provided that the electrical power generated by the continued operation of the fuel cell is fed to a rechargeable battery of the motor vehicle. Additionally or alternatively, it can be provided that the electrical power generated by the operation or continued operation of the fuel cell is fed to other electrical consumers of the motor vehicle, such as an air conditioning system or a heater, or that such electrical consumers of the motor vehicle are automatically activated to ensure the longest possible continued operation of the fuel cell.

[0015] According to a further embodiment, when the deceleration mode is activated, the fuel cell remains in operation after the motor vehicle is shut down and, so to speak, continues to operate. This can involve continued operation of the fuel cell and the associated consumption and / or storage of the inevitably generated electrical power.

[0016] The motor vehicle can be switched off by deactivating the motor vehicle's electrical systems, in particular by a user-initiated switch-off. Switching off the motor vehicle can, in particular, involve switching off the ignition or switching off the motor vehicle's electrical systems that are perceptible to the user. The motor vehicle can also be assumed to be switched off when the user leaves the motor vehicle, when one or more of the motor vehicle's doors are closed from the outside and, if applicable, locked or locked.

[0017] Even in such conditions, the fuel cell can continue to operate in deceleration mode when the vehicle is switched off. The resulting electrical power can be fed to the battery and / or selected electrical consumers of the vehicle.

[0018] According to a further embodiment of the method, the electrical power available as a result of the continued operation of the fuel cell is supplied to a rechargeable battery and / or at least one electrical consumer of the motor vehicle. This enables the continued operation of the fuel cell, because the electrical power generated during the operation of the fuel cell can be dissipated by the fuel cell.

[0019] According to a further embodiment of the method, the continued operation of the fuel cell is regulated depending on the charge level of the rechargeable battery. It can be provided that the power of the fuel cell is controlled or regulated depending on the charge level of the rechargeable battery. For example, if the battery charge level is comparatively low, the fuel cell can be operated at a comparatively high power level. If the battery charge level is comparatively high, the power of the fuel cell can also be throttled if necessary in order to maximize the delay period for initiating the shutdown procedure for the fuel cell.

[0020] According to a further embodiment, when a predetermined maximum charge level of the rechargeable battery is reached, the fuel cell shutdown procedure is initiated, even if the fuel cell or the system for controlling the operation of the fuel cell is in delay mode. In delay mode, the initiation of a fuel cell shutdown procedure can be delayed until the electrical power generated by the operation of the fuel cell can no longer be stored or consumed, or can no longer be stored or consumed sensibly. For example, it can be provided that the maximum charge level of the rechargeable battery is 80% of the battery capacity. If this value is reached by continued operation of the fuel cell, the fuel cell shutdown procedure can be initiated. This can prevent the battery from overcharging.

[0021] According to a further aspect, the present development further relates to a system for controlling the operation of a fuel cell of a motor vehicle. The system comprises a fuel cell control unit for controlling the fuel cell. The system further comprises a motor vehicle control unit, which is data-linked to the fuel cell control unit. The system further comprises an operating element, which is data-linked to the motor vehicle control unit. Finally, at least the motor vehicle control unit and / or the fuel cell control unit can be transferred into a deceleration mode by a user using the operating element.

[0022] In delay mode, the initiation of a fuel cell shutdown procedure occurs with a time delay. The fuel cell continues to operate for a period of time corresponding to the time delay of the fuel cell shutdown procedure. The system is intended in particular for implementing the previously described method for operating a fuel cell of a motor vehicle. In this respect, all features, advantages, and effects previously described with regard to the method also apply equally to the system for controlling the operation of the fuel cell; and vice versa.

[0023] The control element can be arranged as a separate, manually operable control element, for example, in the vehicle interior, such as integrated into a vehicle dashboard. However, the control element can also be emulated by a touch-sensitive display. In particular, the control element can be operated by the user, giving the user the option of activating or deactivating the so-called delay mode.

[0024] It can also be provided that the delay mode is deactivated when the motor vehicle is first started up, and that activation requires active intervention by the end user. Furthermore, it can be provided that the delay mode is automatically deactivated if the vehicle is parked or switched off for an extended period of time, for example, for one or more hours.

[0025] By operating the control element, the deceleration mode for the operation of the fuel cell can be activated. The deceleration mode can also be deactivated again by operating the control element again. Furthermore, the activated deceleration mode can be indicated visually. For example, the motor vehicle can have a corresponding indicator in the instrument panel or on the instrument panel, or possibly also in or on a display.

[0026] When the delay mode is activated, the vehicle control unit and / or the fuel cell control unit is / are configured to delay the initiation of the fuel cell shutdown procedure for as long as possible, even if this would actually be required by the current operating state of the vehicle. In this way, frequent shutdown and restart of the fuel cell, for example, during frequent start-stop processes of the vehicle, can be avoided as much as possible.

[0027] According to a further development of the system, the motor vehicle control unit and / or the fuel cell control unit, when the deceleration mode is activated, is configured to continue operating the fuel cell after the motor vehicle has been shut down and / or switched off. Contrary to the usual control of the fuel cell, shutting down the motor vehicle and / or switching off the motor vehicle does not result in the fuel cell being switched off or initiating the fuel cell shutdown procedure. Instead, the fuel cell is designed to continue operating.

[0028] According to a further embodiment of the system, it comprises a battery control unit for a rechargeable battery. The rechargeable battery can be electrically coupled to the fuel cell. It can be supplied with or charged by electrical power provided by the fuel cell. The motor vehicle control unit and / or the fuel cell control unit is / are configured, when the deceleration mode is activated, to initiate the fuel cell shutdown procedure when a predetermined maximum charge level of the rechargeable battery is reached. For this purpose, the battery control unit can typically communicate with the motor vehicle control unit.

[0029] If the battery control unit detects that the specified maximum charge level, such as the specified maximum permissible charge level of the rechargeable battery, has been reached or is about to be reached, the battery control unit can transmit corresponding signals to the vehicle control unit.

[0030] Upon receipt of these signals, the motor vehicle control unit can be configured to initiate a shutdown procedure for the fuel cell by transmitting corresponding signals or control commands to the fuel cell control unit. The fuel cell control unit is then configured to execute or initiate the shutdown procedure.

[0031] According to a further aspect, a motor vehicle is further provided which has a previously described system for controlling the operation of a fuel cell. The motor vehicle comprises a fuel cell and a battery, which are electrically coupled to the previously described system for controlling the operation of the fuel cell. The motor vehicle can be configured as a passenger car, but also as a delivery vehicle, a bus, or a van.

[0032] Finally, according to a further aspect, a computer program product comprising computer-readable instructions is provided which, when executed by a processor of a motor vehicle control unit and / or when executed by a processor of a fuel cell control unit of a previously described system for controlling the operation of a fuel cell, cause the respective processor to carry out a previously described method for operating a fuel cell. The computer program product or the computer-readable instructions serve to practically implement the previously described method in a previously described system for controlling the operation of a fuel cell. In this respect, all features, advantages, possible applications, and aspects described with regard to the previously described method and the previously described system also apply equally to the computer program product; and vice versa. Short description of the characters

[0033] Further objectives, features, and advantageous embodiments of the present development are explained in the following description of an exemplary embodiment. Herein: Fig. 1 a schematic representation of a motor vehicle, Fig. 2 a block diagram of a fuel cell system, Fig. 3 a block diagram of a fuel cell control and Fig. 4 a flowchart of the method for operating the automotive fuel cell. Detailed description

[0034] In Fig. 1 schematically shows a motor vehicle 1 with a motor vehicle body 2 and an interior 3 functioning as a passenger compartment. The motor vehicle 1 comprises a drive 4, which is typically designed as an electric drive, a battery 5 and a fuel cell 10. By means of the fuel cell 10, electrical power can be generated "on board," which can be supplied to the battery 5 and / or the drive 4. The block diagram of the Fig. 2 shows or symbolizes an interplay between the fuel cell 10 and electrical consumers and the battery 5. The fuel cell 10 can provide electrical power through an electrochemical reaction of hydrogen and oxygen, which can be absorbed by both the rechargeable battery 5 and the drive 4. Furthermore, the motor vehicle 1 can have additional electrical consumers 12, for example in the form of a heater, an air conditioning system, or other electrically operated systems that absorb or consume electrical power.

[0035] The battery 5 can function, in particular, as a so-called buffer battery. It can supply varying electrical power to the drive 4 and the other electrical consumers 12 depending on the operating state. A constant electrical power can typically be drawn from the fuel cell 10. Using the battery 5, or the buffer battery, differences between the current total power consumption of the electrical consumers 12 and the drive 4 compared to the current electrical power generated by the fuel cell 10 can be effectively compensated.

[0036] In Fig. 3 shows a system 21 for controlling the operation of a fuel cell 10. The system 21 comprises a fuel cell control unit 20, which primarily serves to control the fuel cell 10. The system 21 further comprises a motor vehicle control unit 24, which in turn is coupled to the fuel cell control unit 20. The motor vehicle control unit 24 can in particular be designed as a central control unit of the motor vehicle. The system 21 can further optionally comprise a battery control unit 22, which serves to control the battery 5 and which is typically electrically connected to the battery 5. The battery control unit 22 can in particular monitor the state of charge of the battery 5 and control or regulate charging of the battery 5 and discharging of the battery 5.

[0037] The system 21 shown here further comprises an operating element 26, which is data-linked to the motor vehicle control unit 24. The previously described deceleration mode for the fuel cell 10 can be activated using the operating element 26. When the deceleration mode is activated, at least the motor vehicle control unit 20 and / or the fuel cell control unit 20 ensure that the fuel cell 10 is not deactivated prematurely.

[0038] In particular, when the delay mode of system 21 is activated, the initiation of a shutdown procedure of fuel cell 10, which would otherwise occur, is provided at least temporarily. Continued operation of fuel cell 10 is provided during a time interval or a period of this time delay. Continued operation typically occurs for as long as the electrical power generated during continued operation of fuel cell 10 can be absorbed by electrical consumers 12 and / or by rechargeable battery 5.

[0039] If the absorption capacities for the electrical power generated are exhausted or are running low, for example when the charge level of the battery 5 reaches a predetermined maximum charge level, the fuel cell control unit 20 and / or the motor vehicle control unit 24 is designed to initiate the shutdown procedure for the fuel cell 10 even when the deceleration mode is active.

[0040] It is provided in particular that when the deceleration mode is activated, even switching off the motor vehicle 1, in particular locking the motor vehicle 1 from the outside, does not lead to the initiation of the switch-off procedure of the fuel cell 10, but that the fuel cell 10 continues to operate at least for a certain amount of time even in such operating states or configurations of the motor vehicle 1.

[0041] By allowing the user to activate the delay mode themselves via the control element 26, they gain direct control over the operation of the fuel cell 10. The system and method described here can be implemented in practice relatively easily and inexpensively in terms of software and hardware. By delaying or postponing the initiation of the shutdown procedure for the fuel cell 10, its service life can be increased and, if necessary, the energy consumption of the motor vehicle 1 can also be reduced.

[0042] The flow chart of the Fig. Figure 4 shows some of the method steps for operating the fuel cell by way of example. In a first step 100, the motor vehicle 1 or the fuel cell 10 is operated in normal mode. In step 102, a user activates a deceleration mode of the fuel cell 10 using the control element 26.

[0043] By activating the delay mode in step 104, the fuel cell 10 continues to operate even in operating states in which the fuel cell would normally be deactivated, for example as a result of switching off and / or turning off the motor vehicle 1, and a shutdown procedure would have to be initiated.

[0044] The continued operation of the fuel cell 10 in step 104 takes place over a time interval, the length of which may depend on the current operating state of the motor vehicle or the state of charge of the battery 5.

[0045] If, for example, the electrical power generated by the continuous operation of the fuel cell 10 can no longer be stored in the battery 5 or consumed in another way, for example by activating electrical consumers 12, the shutdown procedure of the fuel cell 10 is finally initiated with a time delay in step 106.

[0046] The illustrated embodiments merely show possible configurations of the development, for which numerous further variants are conceivable within the scope of the development. The exemplary embodiments shown are in no way to be interpreted as limiting the scope, applicability, or configuration options of the development. This description merely shows the person skilled in the art one or several possible implementations of an exemplary embodiment. Thus, a wide variety of modifications can be made to the function and arrangement of the described elements without departing from the scope of protection defined by the following claims or their equivalents. List of reference symbols 1 motor vehicle 2 Motor vehicle body 3 Interior 4 Drive 5 Battery 10 fuel cell 12 electrical consumers 20 fuel cell control unit 21 Control system 22 Battery control unit 23 processor 24 Motor vehicle control unit 25 processor 26 Control element QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2017 207 477 A1

[0005]

Claims

[1] Method for operating a fuel cell (10) of a motor vehicle (1) comprising the following steps: - activating a delay mode of the fuel cell (10) by means of an operating element (26) by a user, and - Delaying the initiation of a shutdown procedure of the fuel cell (10) and continuing operation of the fuel cell (10) with the delay mode activated. [2] Method according to claim 1, wherein when the deceleration mode is activated, the fuel cell (10) continues to operate in a continued operation after the motor vehicle (1) has been switched off. [3] Method according to claim 1 or 2, wherein when the deceleration mode is activated, the fuel cell (10) continues to operate after the motor vehicle (1) has been switched off. [4] Method according to one of the preceding claims 2 or 3, wherein an electrical power available as a result of the continued operation of the fuel cell (10) is supplied to a rechargeable battery (5) and / or at least one electrical consumer (12) of the motor vehicle (1). [5] Method according to claim 4, wherein, when the delay mode is activated, the continued operation of the fuel cell (10) is controlled as a function of a charge state of the rechargeable battery (5). [6] Method according to claim 5, wherein when the deceleration mode is activated and when a predetermined maximum charge state of the rechargeable battery (5) is reached, the shutdown procedure of the fuel cell (10) is initiated. [7] System for controlling the operation of a fuel cell (10) of a motor vehicle (1), comprising: - a fuel cell control unit (20) for controlling the fuel cell (10), - a motor vehicle control unit (24) which is data-technically coupled to the fuel cell control unit (20), and - an operating element (26) which is data-technically coupled to the motor vehicle control unit (24), - wherein the motor vehicle control unit (24) and / or the fuel cell control unit (20) can be transferred by a user by means of the operating element (26) into a delay mode in which initiation of a shutdown procedure of the fuel cell (10) takes place with a time delay and wherein the fuel cell (10) continues to be operated over a period of the time delay. [8] System according to claim 7, wherein the motor vehicle control unit (24) and / or the fuel cell control unit (20) is / are designed, when the deceleration mode is activated, to continue operating the fuel cell (10) after the motor vehicle (1) has been turned off and / or switched off. [9] System according to claim 7 or 8, which further comprises a battery control unit (22) for a rechargeable battery (5), wherein the rechargeable battery (5) can be electrically coupled to the fuel cell (10), and wherein the motor vehicle control unit (24) and / or the fuel cell control unit (20) is / are designed, when the deceleration mode is activated, to initiate the shutdown procedure of the fuel cell (10) when a predetermined maximum charge state of the rechargeable battery (5) is reached. [10] Computer program product comprising computer-readable instructions which, when executed by a processor (25) of a motor vehicle control unit (24) and / or when executed by a processor (23) of a fuel cell control unit (20) of a system according to one of the preceding claims 7 to 9, cause the processor to carry out a method for operating a fuel cell (10) of a motor vehicle (1) according to one of the preceding claims 1 to 6.

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