DE102024200784A1 - METHOD AND SYSTEM FOR CONTROLLING A MOTOR VEHICLE FUEL CELL - Google Patents

Abstract

The present development relates to a system (15) and a method for controlling a fuel cell (30) of a motor vehicle (1) located in the interior (14) of a closed housing (10), comprising:- determining a volume of the interior (14) of the housing (10),- controlling the fuel cell (30) and/or a fuel supply (20) of the fuel cell (30) as a function of the determined volume.

Description

Technical area

The present development relates to a method and a system for controlling a motor vehicle fuel cell and a motor vehicle equipped accordingly.

background

Motor vehicles equipped with a fuel cell typically have a hydrogen fuel supply. The fuel supply typically includes a hydrogen tank and hydrogen-carrying lines. Hydrogen is a highly volatile gas. Therefore, common hydrogen fuel supplies exhibit a certain degree of leakage, which is tolerable up to a specified limit.

However, if the vehicle is parked in a closed enclosure, care must be taken to ensure that fuel or hydrogen leakage remains within a specified limit. Furthermore, when operating fuel cells in motor vehicles in a closed enclosure or indoors, strict care must be taken to ensure that the oxygen concentration in the ambient air does not fall below a specified threshold when oxygen is consumed as a reaction gas during fuel cell operation.

A typical limit for hydrogen leakage from fuel cell-powered vehicles is approximately 9 liters of hydrogen per hour. Hydrogen leakage can be quantitatively determined or measured using common measuring devices, such as leak detectors. If the vehicle is located outside of a closed enclosure, such a limit is of course irrelevant. Existing limits are intended for a worst-case scenario in which the volume of the enclosure is just large enough to accommodate the vehicle. For much larger enclosures, such as garages, higher limits for hydrogen leakage and for the operation of the fuel cell within the enclosure would often be permissible.

The objective of this further development is to provide a method and system for controlling a fuel cell in a motor vehicle that enables operation or control of the fuel cell even when the currently applicable limits are exceeded, while simultaneously complying with specified safety standards. This should increase user comfort for the end user while simultaneously reducing the requirements for the technical implementation of, for example, a fuel supply for a fuel cell. The proposed measures should be as cost-neutral or cost-effective as possible and, if possible, implementable without increasing the weight of the vehicle.

Advantageous designs

These objects are achieved by a method and a system for controlling a fuel cell of a motor vehicle located in the interior of a closed housing according to the features of the independent patent claims. Advantageous embodiments are the subject of respective dependent patent claims. Furthermore, a motor vehicle with a fuel cell and a system for controlling the fuel cell according to the features of another independent patent claim is provided.

The method is used to control a fuel cell of a motor vehicle located in the interior of a closed enclosure. It comprises determining the volume of the interior of the enclosure in which the motor vehicle is located, as well as controlling the fuel cell and/or controlling a fuel supply to the fuel cell depending on the determined volume.

In particular, the operating state and/or operating time of the fuel cell can be regulated based on the determined volume. Furthermore, a limit value for the leakage of the fuel supply with regard to hydrogen loss can be determined or varied depending on the determined volume. If the volume of the enclosure is comparatively large, for example, a comparatively high limit value for the leakage of the fuel supply is tolerable. Furthermore, with a comparatively large enclosure volume, the fuel cell can be operated for a comparatively long period of time or with a comparatively high fuel consumption before the oxygen content in the enclosure falls below a predetermined threshold.

Determining the volume of the enclosure enables adaptive control of the fuel cell and the fuel supply for the fuel cell, which is tailored to the respective situation of the vehicle environment.

According to a further development of the process, the volume of the interior is determined by The distance is determined by measuring one or more distances between the motor vehicle and a wall of the enclosure using at least one distance sensor or multiple distance sensors of the motor vehicle. One or more distance sensors, for example, located at the front of the vehicle, at the rear of the vehicle, and/or on one or more sides of the motor vehicle, can be used as distance sensors. Typically, distance sensors of a parking assistance system can provide corresponding distance information to one or more walls of the enclosure.

In this respect, existing distance sensors in the vehicle can be used to measure or determine the volume of the enclosure, eliminating the need to implement any additional hardware or system components. The distance data obtained from existing distance sensors can be used to determine or calculate the volume of the enclosure.

This allows the implementation effort for the process to be kept as low as possible. This avoids any increase in the weight of the vehicle, as well as any significant increase in the costs of manufacturing the vehicle and/or implementing the process.

According to a further embodiment of the method, the operating time and/or operating state of the fuel cell is regulated depending on the determined volume. This applies in particular to application scenarios in which the fuel cell must be operated before the vehicle is started up, for example, to pre-temperature the vehicle or to charge a vehicle battery while the vehicle is stationary. The closed housing, or its volume, defines a total air volume, based on which the operating time of the fuel cell can be determined for a given operating state of the fuel cell.

The available air volume can also vary depending on the ambient pressure, air humidity, and air temperature. Therefore, the parameters of ambient pressure, air humidity, and/or air temperature can be considered accordingly when calculating or estimating the air volume available in the closed enclosure, or the molecular mass of the available oxygen.

For example, with a comparatively small enclosure volume, the fuel cell can only be operated for a comparatively short period of time until a critical lower limit for the remaining oxygen concentration in the ambient air inside the enclosure is reached. With a comparatively large enclosure with a correspondingly large volume, the operating time of the fuel cell can be significantly extended because significantly more oxygen is available for the fuel cell. If the critical limit is reached, or a maximum operating time calculated based on the volume is reached, the operation of the fuel cell can be stopped or at least throttled so as not to further reduce the oxygen concentration in the ambient air of the vehicle inside the enclosure.

According to a further embodiment, the fuel supply for the fuel cell is regulated depending on the determined volume of the enclosure and a measurable leakage of the fuel supply. In particular, a limit value for a permissible leakage of the fuel supply can be variably adjusted based on the determined volume of the enclosure.

If the enclosure volume is comparatively small, a comparatively small limit value for permissible leakage in the fuel supply must be set. If the volume is comparatively large, the limit value can be increased because, due to the increased volume, it can be assumed that even with a larger leakage of hydrogen from the fuel supply, a maximum limit value for the hydrogen concentration in the ambient air inside the enclosure will not (yet) be reached. However, if the limit value for the hydrogen concentration in the interior of the enclosure adapted on the basis of the volume determination or volume measurement is reached, or if the measurable leakage in the fuel supply is greater than the adaptively set limit value or the limit value set based on the determined volume, the fuel supply is interrupted for safety reasons. The system is put into a lockout state, which requires the intervention of a service technician who can ensure the operational safety of the fuel cell or fuel supply before it can be restarted.

According to a further embodiment of the method, a leakage of the fuel supply is measured by means of a leak detector, and the permissible leakage limit of the fuel supply is varied depending on the determined volume. In other words, the permissible leakage limit of the fuel supply can be Depending on the determined volume, the leakage limit can be adjusted as needed. If the interior volume of the enclosure is comparatively small, a comparatively small leakage limit should be provided.

With a comparatively large interior volume of the enclosure, the leakage limit can be set significantly higher. Such a higher leakage limit enables safe operation of the fuel cell and fuel supply without premature and unnecessary safety-related interruption or emergency shutdown of the fuel cell and/or fuel supply.

In a further aspect, the present development relates to a system for controlling a fuel cell of a motor vehicle located in the interior of a closed enclosure. The system comprises a device for determining the volume of the interior of the enclosure, as well as a controller for controlling the fuel cell and/or a fuel supply to the fuel cell depending on the determined volume. The controller for the fuel cell or the fuel supply is linked via data technology to the device for determining the volume of the interior.

The device for determining the volume of the interior is designed in particular to determine, estimate or calculate the volume of the interior in which the vehicle is parked. The device for determining the volume of the interior is designed in particular for the quantitative determination of the volume. Depending on the volume of the closed interior, the fuel cell and the fuel supply for the fuel cell can then be adjusted as required in order to ensure, on the one hand, that the hydrogen concentration in the environment of the motor vehicle does not rise above a predetermined limit as a result of a leak in the fuel supply and/or that the oxygen concentration in the ambient air in the interior of the enclosure does not fall below a predetermined limit.

According to a further embodiment of the system, the device for determining the volume of the interior of the closed enclosure comprises at least one distance sensor and an evaluation unit data-linked thereto, which are designed to determine or calculate the volume of the interior by measuring a distance between the motor vehicle and at least one wall of the enclosure using the at least one distance sensor. The enclosure may have one or more walls. Likewise, the device for determining the volume may comprise several distance sensors, which are similarly data-linked to the evaluation unit provided for this purpose.

For example, the front, rear, and lateral distance of the vehicle to the wall or walls of the enclosure can be measured, and the volume of the interior can be determined based on these measurements. A vertical extension of the interior, or an extension of the interior in the direction of the vehicle's vertical axis, may be unnecessary in this case. At least the corresponding dimension of the vehicle along the vehicle's vertical axis can be assumed as the minimum enclosure dimension.

The distance sensor(s) can be implemented, for example, as sensors of a parking assistance system of the motor vehicle. The distance sensors can, for example, comprise one or more ultrasonic sensors, one or more lidar sensors, or optical sensors, by means of which a distance between the respective sensor and the surroundings of the motor vehicle, for example, between the sensor and a wall of the enclosure, can be quantitatively determined or measured.

According to a further embodiment, the system comprises a controller for the fuel cell, which is designed to regulate an operating time and/or an operating state of the fuel cell depending on the determined volume. This controller is particularly designed to ensure, based on the determined volume, that the oxygen concentration in the interior of the enclosure does not fall below a predetermined minimum limit. In this way, the fuel cell can also be operated while the motor vehicle is stationary, for example, to pre-temperature the motor vehicle and/or to charge a motor vehicle battery while the motor vehicle remains in the interior of the enclosure.

The control system for the fuel cell can, in particular, be designed to change the operating state of the fuel cell or to interrupt its operation when a fuel cell operating time previously calculated or determined based on the determined volume is reached. This ensures that the oxygen concentration in the ambient air inside the enclosure does not fall below the specified minimum limit.

According to a further development of the system, the control for the fuel cell is also Designed to regulate, and if necessary interrupt, the fuel supply to the fuel cell depending on the determined volume and the measurable or measured leakage of the fuel supply. This ensures that any hydrogen leakage from the fuel supply remains within specified and permissible limits or tolerances that are tailored to the respective volume of the interior of the enclosure.

The system for controlling a fuel cell described here is particularly designed for implementing or executing the method for controlling the fuel cell as described herein. In this respect, all features, advantages, and possible applications previously described with regard to the method also apply equally to the system; and vice versa.

Finally, according to a further aspect, a motor vehicle with a fuel cell and a fuel supply system is provided. The motor vehicle is, in particular, equipped with a previously described system for controlling the fuel cell. In this respect, all features, advantages, and possible applications described above with regard to both the system and the method apply equally to the motor vehicle.

Short description of the characters

• 1 eine schematische Darstellung eines Kraftfahrzeugs mit einer Brennstoffzelle,
• 2 Blockschaltbild des Kraftahrzeugs in einer geschlossenen Umgebung,
• 3 ein erstes Flussdiagramm des Verfahrens zur Steuerung der Kraftfahrzeug-Bennstoffzelle,
• 4 ein weiteres Flussdiagramm des Verfahrens zur Steuerung der Kraftfahrzeug-Bennstoffzelle.

Further objects, features, and advantageous applications of the present method and system are explained in the following description with reference to the drawings.

• 1 a schematic representation of a motor vehicle with a fuel cell,
• 2 Block diagram of the motor vehicle in a closed environment,
• 3 a first flowchart of the method for controlling the motor vehicle fuel cell,
• 4 another flowchart of the method for controlling the automotive fuel cell.

Detailed description

The 1 The schematically shown motor vehicle 1 has a motor vehicle body 2 and an interior 3 functioning as a passenger compartment. The motor vehicle 1 is parked within a closed enclosure 10, for example in the form of a garage. A schematic plan view of the motor vehicle from above is shown in 2 in relation to the housing 10. The motor vehicle 1 is shown purely schematically in the form of a block diagram. The motor vehicle 1 comprises a fuel cell 30 and a fuel supply 20, which is connected to the fuel cell 30 in a fluid- and/or gas-conducting manner.

The fuel supply 20 comprises a fuel tank 22 and a leak detector 24, by means of which a fuel leak from the area of the fuel supply can be detected or measured. Furthermore, the motor vehicle comprises a system 15 for controlling the fuel cell 30 or for controlling the fuel supply 20. In addition to the fuel cell 30 and/or the fuel supply 20, the system 15 comprises a controller 26, by means of which an operating state and/or operating time of the fuel cell 30 can be regulated. Furthermore, the operating state of the fuel supply 20 can also be monitored or regulated by means of the controller 26.

Furthermore, the motor vehicle 1 comprises a device 40 for determining the volume of an interior space 14 of the housing 10. The device 40 comprises an evaluation unit 41, which is data-linked to one or more distance sensors 42. The distance sensors 42 can be arranged either at the rear or at the front of the motor vehicle. In particular, they can be 2 Determine the outlined distance d to one or more side walls 11, 12 of the housing 10. Sensors 42 arranged at the front or rear can determine a distance to an end wall 12 of the housing 10. Sensors 42 arranged laterally can determine or measure a distance to a side wall 11. By means of the distance sensors 42 and the evaluation unit 41 coupled thereto for data purposes, it is possible to determine at least one cross-sectional area of a side wall or side walls 11, 12 of the housing 10 in order to be able to at least estimate or calculate the volume of the interior space 14 of the housing 10.

In the vertical direction, i.e. in the z-direction, the corresponding dimension or the extension of the motor vehicle along the vehicle's vertical axis (z-axis) can be assumed as the minimum height.

The distance sensors 42 can be implemented, in particular, as distance sensors of a parking assistance system. In this respect, components present on or in the motor vehicle can be used to determine the volume of the interior 14 of the housing 10.

Possible operating modes of the system 15, or the method for controlling the fuel cell 30, are shown in the two flow diagrams according to the 3 and 4 schematically outlined. In the flow chart of the 3 In a first step 100, the distance of the motor vehicle 1 to one or more side or end walls 11, 12 of the enclosure 10 is measured. For example, the distance to a side wall 11 of the enclosure 10 can be determined using a number of distance sensors 42. The distance to one or more end walls 12 of the enclosure 10 can be determined using further sensors 42. Based on the distance measurement, the minimum volume of the enclosure 10 can then be determined in step 100 using the evaluation unit 41.

In step 102, an inevitable leak in the fuel supply 20 for the fuel cell 30 is measured, for example, using the leak detector 24. In a further step 104, the maximum permissible limit for the leak is adjusted depending on the determined volume of the interior 14 of the housing 10, or raised or lowered to a limit corresponding to the volume. In the subsequent step 106, the leak measured in the previous step 102 is compared with the volume-dependent limit. If the comparison in step 106 shows that the measured leak is below the threshold, the diagnostic method ends in step 108, and the fuel cell 30 or the fuel supply 20 can continue to operate in a normal operating mode.

However, if the comparison in step 106 shows that the measured leakage reaches or is above the limit value, the method continues with step 110, in which appropriate countermeasures are taken, such as switching off the fuel supply 20 and/or activating an alarm system that prevents the end user from operating the motor vehicle 1 and/or activating the fuel cell.

The procedure according to 4 In a first step 200, the method also provides for the measurement of one or more distances d between the motor vehicle 1 and the housing 10, in particular between the motor vehicle and the side walls 11, 12 of the housing 10. Based on this measurement, a minimum volume of the housing 10 can be determined in step 200. In the subsequent step 202, the fuel cell is put into operation, for example, to heat the passenger compartment or the vehicle interior 3 to a predetermined temperature before starting the journey. In step 204, the maximum operating time of the fuel cell 30 is calculated, assuming that the motor vehicle remains within the closed housing for that period.

The calculation in step 204 is based on the volume of the interior 14 of the housing 10 and assuming an oxygen consumption corresponding to the respective operating state of the fuel cell 30. In step 206, the fuel cell 30 is then operated for the calculated period of time, for example, to heat the passenger compartment or the interior 3 of the motor vehicle 1 to a predetermined temperature before operation of the fuel cell 30 is terminated or throttled in step 208, for example, when either the predetermined temperature in the vehicle interior 3 has been reached or when the maximum permissible operating time of the fuel cell 30, which was calculated based on the available volume in the interior of the closed housing, has been reached.

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

body

10

Enclosure

11

side wall

12

front wall

14

Interior

15

system

20

Fuel supply

22

tank

24

Leakage detector

26

steering

30

fuel cell

40

Furnishings

41

Evaluation unit

42

Distance sensor

Claims (10)

Method for controlling a fuel cell (30) of a motor vehicle (1) located in the interior (14) of a closed housing (10), comprising: - determining a volume of the interior (14) of the housing (10), - controlling the fuel cell (30) and/or a fuel supply (20) of the fuel cell (30) as a function of the determined volume. Procedure according to Claim 1 , wherein the volume of the interior space (14) is determined by measuring a distance between the motor vehicle (1) and a wall (11, 12) of the housing (10) by means of at least one distance sensor (42) of the motor vehicle (1). Method according to one of the preceding claims, wherein an operating time and/or an operating state of the fuel cell (30) is regulated as a function of the determined volume. Method according to one of the preceding claims, wherein the fuel supply (20) for the fuel cell (30) is regulated as a function of the determined volume and as a function of a measurable leakage of the fuel supply (20). Procedure according to Claim 4 wherein a leakage of the fuel supply (20) is measured by means of a leakage detector (24) and a permissible leakage limit value is varied depending on the determined volume. System (15) for controlling a fuel cell (30) of a motor vehicle (1) located in the interior (14) of a closed housing (10), comprising: - a device (40) for determining a volume of the interior (14) of the housing (10), - a controller (26) for controlling the fuel cell (30) and/or a fuel supply (20) of the fuel cell (30) as a function of the determined volume. System (15) according to Claim 6 , wherein the device (40) for determining the volume of the interior space (14) comprises at least one distance sensor (42) and an evaluation unit (41) coupled thereto for data purposes, which are designed to determine the volume of the interior space (14) by measuring a distance between the motor vehicle (1) and a wall (11, 12) of the housing (10) by means of the at least one distance sensor (42). System (15) according to one of the preceding Claims 6 or 7 , wherein the control (26) for the fuel cell (30) is designed to regulate an operating time and/or an operating state of the fuel cell (30) as a function of the determined volume. System (15) according to one of the preceding Claims 6 until 8 , wherein the controller (26) is designed to regulate the fuel supply (20) for the fuel cell (30) as a function of the determined volume and as a function of a measurable leakage of the fuel supply (20). Motor vehicle (1) with a fuel cell (30) and with a system (15) according to one of the preceding Claims 6 - 9 .