Method and control device for operating a motor vehicle configured as a fuel cell vehicle

Abstract

Method and control device for operating a motor vehicle configured as a fuel cell vehicle. The method has the following steps: for a future to be traveled route (preview horizon), an electrical power requirement of the motor vehicle is ascertained for reference points along the preview horizon. From the ascertained electrical power requirement, an average power requirement along the preview horizon is ascertained. In the case of an assumption that a fuel cell system is operated along the preview horizon in a constant operating mode to provide the average power requirement, a state of charge curve of a high-voltage energy store along the preview horizon is ascertained; if the ascertained state of charge curve lies within an invariant SOC boundary, the fuel cell system is operated to provide the average power requirement, and if the ascertained state of charge curve lies partly outside the invariant SOC boundary, an adjustment is made to the power to be provided by the fuel cell system, so that the state of charge curve of the high-voltage energy store along the preview horizon still or more greatly or more lies within the aforementioned SOC boundary.

Description

Technical Field

[0001] This invention relates to a method for operating a motor vehicle configured as a fuel cell vehicle. Furthermore, this invention also relates to a control device for operating a motor vehicle configured as a fuel cell vehicle. Background Technology

[0002] Motor vehicles configured as fuel cell vehicles are equipped with a high-voltage system, also known as a high-voltage circuit. Other components of a motor vehicle configured as a fuel cell vehicle include: an electric motor coupled to the high-voltage system and used as a drive unit; an electrical high-voltage energy storage device also coupled to the high-voltage system; and a fuel cell system coupled to the high-voltage system. The electric motor draws electrical power from the high-voltage system during motor-driven operation and feeds electrical power to the high-voltage system during generator-driven operation. The electrical high-voltage energy storage device draws electrical power from the high-voltage system during charging operation and feeds electrical power to the high-voltage system during discharging operation. In a motor vehicle configured as a fuel cell vehicle, the fuel cell system also feeds electrical power to the high-voltage system when the fuel cell system is activated, i.e., when current is generated from hydrogen.

[0003] DE 10 2021 004 503 A1 discloses a method for altering the operating strategy of a motor vehicle constructed as a fuel cell vehicle, wherein three strategic objectives can be followed: performance optimization, efficiency optimization, and service life optimization.

[0004] US 2015 / 0134174 A1 discloses a method for operating a motor vehicle that uses an electric motor as a drive unit, wherein the energy required for this is always on standby in a battery. An auxiliary power unit is used as a source of electrical energy, which can be implemented as an internal combustion engine or a fuel cell generator.

[0005] The requirement is to enable motor vehicles configured as fuel cell vehicles to operate with optimal power distribution between the fuel cell system and the high-voltage energy storage, more specifically, to operate with reduced dynamic load on the fuel cell system and while adhering to operating limitations for the high-voltage energy storage. Summary of the Invention

[0006] Therefore, the objective of this invention is to provide a novel method and control apparatus for operating a motor vehicle configured as a fuel cell vehicle. This objective is achieved by the method according to claim 1 and the control apparatus according to claim 9.

[0007] According to the present invention, for the foreseeable horizon, that is, for the future journey of the motor vehicle, for a reference point along the foreseeable horizon ( The electric power demand of the motor vehicle is obtained. From the electric power demand of the motor vehicle obtained from these reference points relative to the foreseeability horizon, the average electric power demand of the motor vehicle along the foreseeability horizon is obtained. Assuming the fuel cell system operates in a constant operating mode along the foreseeability horizon to provide the average electric power demand, the state of charge (SOC) curve of the high-voltage energy storage device along the foreseeability horizon is obtained. If the obtained SOC curve of the high-voltage energy storage device along the foreseeability horizon lies within the invariant SOC boundary of the high-voltage energy storage device along the foreseeability horizon, the fuel cell system is operated to provide the average power demand. If the obtained SOC curve of the high-voltage energy storage device along the foreseeability horizon partially lies outside the invariant SOC boundary of the high-voltage energy storage device along the foreseeability horizon, the power to be provided by the fuel cell system is adjusted so that the SOC curve of the high-voltage energy storage device along the foreseeability horizon remains, or is more, within the invariant SOC boundary of the high-voltage energy storage device along the foreseeability horizon.

[0008] The method according to the invention provides a predictive power allocation between the fuel cell system and the high-voltage energy storage device for the future journey of a motor vehicle configured as a fuel cell vehicle. This predictive power allocation reduces the dynamic load on the fuel cell system and keeps the high-voltage energy storage device operating within permissible SOC boundaries. This reduces hydrogen consumption due to the fuel cell system. Furthermore, it reduces the risk of damage to both the fuel cell system and the high-voltage energy storage device.

[0009] The foreseeability horizon has a limited number of reference points. The first reference point of the foreseeability horizon is located at its beginning, and the last reference point is located at its end. Reference points along the foreseeability horizon are locations for which known function values, such as target electrical power requirements, are obtained. Specifically, the distance between reference points is related to the length of the foreseeability horizon. If the foreseeability horizon is relatively short, the distance between the reference points will be smaller or shorter compared to a relatively long foreseeability horizon. The number of reference points is preferably independent of the length of the foreseeability horizon; however, the distance between reference points is preferably related to the length of the foreseeability horizon. In particular, the distance between reference points along the foreseeability horizon is equal or constant.

[0010] The State of Charge (SOC) of an electrical high-voltage energy storage device refers to the state of charge of the device. SOC fluctuates between 0% and 100%. 100% SOC corresponds to a fully charged high-voltage energy storage device. 0% SOC corresponds to a fully discharged high-voltage energy storage device. The boundaries of SOC correspond to the states of charge that must not be lowered or higher than the permitted levels. Therefore, it must not fall below the lower boundary of SOC (also known as the minimum permissible SOC or state of charge), and must not exceed the upper boundary of SOC (also known as the maximum permissible SOC). SOC boundaries can also be referred to as SOC boundary values.

[0011] Therefore, preferably, when the change in the elevation curve of the total future journey exceeds a boundary value, the journey up to the first high or low point of the total journey is selected as the foreseeability horizon; and / or when the change in the elevation curve of the total future journey is less than the boundary value, a journey of a first length predetermined by the control side is selected as the foreseeability horizon; and / or when the predicted average speed along the entire journey is lower than the boundary value, a journey of a second length predetermined by the control side is selected as the foreseeability horizon. Thus, the foreseeability horizon can be optimally selected based on the total journey. Based on the terrain of the total journey and the predicted average speed along that total journey, the foreseeability horizon can be optimally selected in this manner and method to determine the optimal power distribution between the fuel cell system and the high-voltage energy storage device.

[0012] Preferably, for the foreseeable horizon, i.e., for the future journey of the vehicle, the vehicle's electrical power demand at the reference point is determined based on the vehicle's driving resistance and its secondary energy consumption. Therefore, the optimal power allocation between the fuel cell system and the high-voltage energy storage device can be determined more accurately.

[0013] Preferably, the average electric power demand of the motor vehicle along the foreseeability horizon is obtained by converting the electric power demand at a reference point into a time-varying power demand of the motor vehicle based on the predicted travel speed, integrating this time-varying power demand along the foreseeability horizon, and dividing by the predicted travel time relative to the foreseeability horizon. This method is particularly advantageous for obtaining the average electric power demand along the foreseeability horizon.

[0014] According to the first variant, when the known portion of the state of charge (SOC) curve along the foreseeability horizon is outside the constant state of charge (SOC) boundary along the foreseeability horizon, in order to adjust the power to be provided by the fuel cell system, the power to be provided by the fuel cell system is first adjusted for the sub-stroke along the foreseeability horizon up to a first reference point where the SOC curve is outside the constant SOC boundary, such that the SOC curve up to that reference point is within the SOC boundary. Preferably, these steps are then repeated until the SOC curve is within the SOC boundary for all or as many subsequent sub-strokes as possible. According to the second variant, when the known portion of the state of charge (SOC) curve along the foreseeability horizon lies outside the constant state of charge (SOC) boundary along the foreseeability horizon, in order to adjust the power to be provided by the fuel cell system, firstly, reference points are identified where the deviation between the SOC curve and the constant lower or upper SOC boundary is greatest at the location of the foreseeability horizon. Subsequently, the power to be provided by the fuel cell system is adjusted such that the SOC curve lies within the SOC boundary with respect to these reference points. Preferably, these steps are then repeated until the SOC of the high-voltage energy storage device is within the SOC boundary at all or as many reference points as possible. Using these two variants, namely the first and second variants described above, it is particularly advantageous to adjust the power to be provided by the fuel cell system to ensure that the high-voltage energy storage device operates within the predetermined constant SOC boundary with respect to its SOC curve. Attached Figure Description

[0015] Preferred improvements are derived from the dependent claims and the following description. Embodiments of the invention are explained in detail with reference to the accompanying drawings, without being limited thereto. Wherein:

[0016] Figure 1 A sketch of a motor vehicle constructed as a fuel cell vehicle is shown;

[0017] Figure 2 A signal flow diagram illustrating the method for operating a fuel cell vehicle according to the present invention is shown;

[0018] Figure 3 A signal flow diagram illustrating a first variant of the method according to the present invention is shown;

[0019] Figure 4 A signal flow diagram is shown to illustrate a second variation of the method according to the invention. Detailed Implementation

[0020] Figure 1A block diagram of a motor vehicle 10 configured as a fuel cell vehicle is shown in a highly schematic manner. The motor vehicle has a high-voltage system 11, which is also referred to as a high-voltage circuit.

[0021] The motor vehicle 10 has a motor 12 coupled to a high-voltage system 11, which serves as a drive unit. This motor draws electrical power from the high-voltage system 11 in motor-type operation according to arrow 13, and feeds electrical power to the high-voltage system 11 in generator-type operation according to arrow 14. Furthermore, the motor vehicle 10 also has an electrical high-voltage energy storage device 15 coupled to the high-voltage system 11. This electrical high-voltage energy storage device is also referred to as a traction battery. During charging operation, the high-voltage energy storage device 15 draws electrical power from the high-voltage system 11 according to arrow 16. During discharging operation, the respective high-voltage energy storage device 15 feeds electrical power to the high-voltage system 11 according to arrow 17.

[0022] Furthermore, the motor vehicle 10, which is configured as a fuel cell vehicle, also has a fuel cell system 18. Thus, when the fuel cell system 18 is activated, that is, when current is generated from hydrogen, the fuel cell system feeds electrical power to the high-voltage system 11 according to arrow 19.

[0023] As another component of the motor vehicle 10, which is configured as a fuel cell vehicle, Figure 1 An optional brake 20 is also shown, which, when activated, draws electrical power from the high-voltage system 11 according to arrow 21. However, this brake 20 is not mandatory.

[0024] The present invention aims to enable such a motor vehicle 10 to operate along its intended journey with optimal power distribution between the fuel cell system 18 and the high-voltage energy storage device 15, in order to minimize hydrogen consumption, in particular, in the fuel cell system 18, and to keep the risk of damage to the fuel cell system and the high-voltage energy storage device 15 very low. Reference will be made below. Figures 2 to 4 The method according to the present invention is described.

[0025] First, according to Figure 2 Box 22 in the diagram defines a forward horizon for optimizing power distribution between the fuel cell system 18 and the high-voltage energy storage device 15. The forward horizon refers to the future distance the vehicle is expected to travel.

[0026] In order to determine the respective foreseeability horizons, the terrain of the total journey to be traversed by the motor vehicle 10 and the average speed along the total journey predicted based on the speed limit of the total journey are considered, so as to divide the total journey into several journeys that are optimal for power distribution optimization, and thus foreseeability horizons.

[0027] When the change in the elevation curve of the total journey exceeds the boundary value, that is, when the total journey has a highly variable elevation curve, especially when the journey up to the first high or low point of the total journey is selected as the foreseeable horizon.

[0028] Conversely, when the change in the elevation curve of the total future journey is less than the boundary value, i.e. when there is a small change in the elevation curve, the journey with a first length (e.g., 100 km) predefined on the control side is selected as the foreseeable horizon.

[0029] Specifically, the aforementioned determination of the foreseeability horizon is performed when the predicted average speed along the total distance is greater than the boundary value. Conversely, if the predicted average speed along the total distance to be traversed in the future is less than the boundary value, i.e., especially if there are urban routes, a distance with a predetermined second length on the control side is selected as the foreseeability horizon. This second length is less than the predetermined first length, wherein the predetermined second length may, for example, be less than 50 km.

[0030] In this manner and method, the total journey can be divided into multiple foreseeable horizons. For each foreseeable horizon, the steps described below are performed independently. The determination of the foreseeable horizons is based primarily on map data or GPS data of the total journey to be traversed. The foreseeable horizons determined in box 22 are divided by a limited number of reference points, wherein the distance between the reference points is smaller if the foreseeable horizon is shorter. Therefore, the number of reference points is particularly independent of the length of the foreseeable horizon.

[0031] After defining and dividing the foreseeability horizon in box 22, the electric power requirement of the motor vehicle 10 is determined in box 23 for the foreseeability horizon and for these reference points along the foreseeability horizon. This determination of the electric power requirement of the motor vehicle 10 for each reference point of the foreseeability horizon with respect to the high-voltage system 11 is based on the driving resistance along the foreseeability horizon (i.e., dependent on air resistance, rolling resistance, climbing resistance, and acceleration resistance).

[0032] The driving resistance is multiplied, in particular, by a speed prediction calculated based on the speed limit at a reference point, to obtain a prediction of the electrical power required at the output of the vehicle 10. This power prediction at the output can be corrected using the efficiency of the vehicle 10's drive system to deduce the electrical power required by the high-voltage system 11 at the reference point. Here, in addition to the driving resistance of the vehicle 10, secondary power consumers that draw electrical power from the high-voltage system 11 are also considered. These secondary power consumers may be, for example, a cooling system, an air conditioning system, or a power-take-out device.

[0033] After obtaining the power demand for each reference point of the foreseeability horizon in box 23, the average power demand of the motor vehicle (i.e., the high-voltage system 11) along the distance to be traversed, and thus along the foreseeability horizon, is obtained from the power demand of the motor vehicle at the reference points of the foreseeability horizon. In order to obtain the average power demand, in particular, the power demand of the high-voltage system 11 at the reference points is converted into a time-varying power demand based on the predicted travel speed at the reference points, wherein the time-varying power demand is integrated along the foreseeability horizon, more precisely along the predicted travel time, and then divided by the predicted travel time, so that the average power demand of the motor vehicle (i.e., the high-voltage system 11) is finally obtained in box 24.

[0034] Subsequently, in box 25, assuming that the fuel cell system 18 operates in a constant operating mode along the foreseeable horizon and further along the future journey to provide the average electrical power demand known in box 24, the state-of-charge curve of the high-voltage energy storage 15 along the foreseeable horizon is obtained.

[0035] To obtain the state-of-charge (SOC) curve of the high-voltage energy storage device 15 in block 25, the integrated electrical power flows into and out of the high-voltage energy storage device 15 are added based on a pre-defined battery capacity and initial SOC of the high-voltage energy storage device 15. Here, for each reference point of the foreseeability horizon, the electrical power of the high-voltage energy storage device 15 is calculated by subtracting the electrical power provided by the fuel cell system 18 from the power demand of the high-voltage system 11, preferably after correcting for accumulated battery losses in the high-voltage energy storage device 15. Battery losses can be considered using a loss model for the high-voltage energy storage device 15.

[0036] Furthermore, the state-of-charge curve can also be obtained by relying on the state-of-charge-related performance of the high-voltage energy storage device 15. If the motor vehicle 10 configured as a fuel cell vehicle has... Figure 1 The brake 20 can then dissipate excess electrical energy. This prevents the high-voltage energy storage device 15 from being charged beyond its SOC upper limit.

[0037] In the subsequent box 26, it is checked whether the state of charge (SOC) curve of the high-voltage energy storage device 15, as known in box 25, lies within the SOC boundary that remains unchanged along the foresight horizon for the high-voltage energy storage device 15. Therefore, it is assumed that, for the high-voltage energy storage device 15, the lowest SOC boundary, or lower SOC boundary, and the highest SOC boundary, or upper SOC boundary, are predetermined and known on the control side, just like the battery capacity of the high-voltage energy storage device 15.

[0038] If it is confirmed in box 26 that the state of charge curve along the foresight horizon known in box 25 lies within the invariant SOC boundary, then proceed from box 26 to box 27, so that the fuel cell system 18 can subsequently operate at a constant operating point to provide the average electrical power demand of the high-voltage system 11 known in box 24, so that the high-voltage energy storage 15 can also operate within its SOC boundary.

[0039] Conversely, if it is confirmed in box 26 that the known portion of the state of charge curve along the foreseeability horizon lies outside the invariant SOC boundary along the foreseeability horizon and further along the path to be traversed, then proceed from box 26 to box 28 to adjust the power to be provided by the fuel cell system in box 28 such that the state of charge curve of the high-voltage energy storage 15 remains, or more significantly, within the invariant SOC boundary along the foreseeability horizon, so that the fuel cell vehicle can subsequently operate in box 27 taking into account the electrical power provided by the fuel cell system as adjusted in box 28.

[0040] In block 28, adjusting the power supplied by the fuel cell system 18 to keep the state-of-charge curve of the high-voltage energy storage device 15 within the SOC boundary to a greater extent or more preferably completely can be achieved in different ways and methods, among which, refer to Figure 3 and Figure 4 Preferred variations for adjusting the electrical power to be provided by the fuel cell system 18 are described.

[0041] In a first variant of the invention, when it is confirmed in block 26 that the known portion of the state of charge curve along the foreseeability horizon is outside the SOC boundary which is constant with respect to the foreseeability horizon, the following reference points of the foreseeability horizon are first determined in block 29: at these reference points, the known state of charge curves are outside the SOC boundary.

[0042] In box 30, starting from the starting point of the foreseeable horizon, the following sub-journey of the foreseeable horizon is determined: at this sub-journey, the state of charge curve is first located outside the invariant SOC boundary.

[0043] Subsequently, in block 31, the electrical power to be provided by the fuel cell system 18 is adjusted so that the reference point for the sub-stroke determined in block 30 (for which the state of charge curve deviates most in absolute value from its respective SOC boundary) lies within the SOC boundary.

[0044] To adjust the electrical power supplied by the fuel cell system 18, the electrical power supplied by the fuel cell system 18 can be increased when the state of charge (SOC) is below the lower boundary of the minimum SOC. Alternatively, the electrical power supplied by the fuel cell system 18 can be reduced when the known state of charge curve exceeds the upper boundary of the SOC, or the maximum SOC boundary.

[0045] The adjustment of the electrical power to be provided by the fuel cell system 18 is carried out from the current starting reference point of each sub-journey until the reference point where the absolute value of the state of charge curve deviates from the respective SOC boundary, as known in box 31.

[0046] The electrical power to be adjusted depends on the difference between the corresponding SOC boundary at or near the reference point known in block 30 and the state of charge of the high-voltage energy storage 15.

[0047] In box 32, based on the power of the fuel cell system 18 to be provided, adjusted in box 31, a new state-of-charge curve for the high-voltage energy storage 15 is obtained across the entire foreseeability horizon, as described above. Figure 2 As stated above.

[0048] In the subsequent box 33, it is checked whether the new state-of-charge curve for the current sub-journey with respect to the foreseeability, as learned in box 32, lies inside or outside the SOC boundary that remains unchanged with respect to the foreseeability. If the adjusted state-of-charge curve learned in box 32 lies outside the SOC boundary that remains unchanged with respect to the foreseeability, then return to box 30. At this point, the reference point where the adjusted new state-of-charge curve lies outside the effective SOC boundary with respect to the foreseeability changes, thus causing the new sub-journey with respect to the foreseeability to be learned in box 30.

[0049] Conversely, if it is confirmed in box 33 that the new state-of-charge curve for the current sub-trip is within the SOC boundary, proceed from box 33 to box 34, where it is checked whether the end point of the foreseeability horizon has been reached. If it is confirmed in box 34 that the end point of the foreseeability horizon has been reached, meaning there are no further sub-trips beyond that foreseeability horizon that could cause the state-of-charge curve to be outside the SOC boundary, proceed from box 34 to box 27. If it is confirmed in box 34 that the end point of the foreseeability horizon has not yet been reached, meaning there are still further sub-trips that could cause the state-of-charge curve to be outside the SOC boundary, proceed from box 34 to box 35, so that the end point of the sub-trip previously checked in terms of the state-of-charge curve is used as the starting point for the next sub-trip, and then return to box 29.

[0050] When adjusting the electrical power to be provided by the fuel cell system 18 in box 31, if the operating mode of the fuel cell system 18 required to adjust the electrical power to be provided by the fuel cell system 18 is lower than the minimum permissible operating mode, then the fuel cell system 18 is shut down.

[0051] The adjustment of the electrical power to be provided by the fuel cell system 18 in block 31 can be based on the expected degree of aging of the fuel cell system 18 due to shutting it off. If the minimum permissible operating mode of the fuel cell system 18 results in a lower degree of aging of the fuel cell system 18 than that resulting from shutting it off, it is preferable not to shut down the fuel cell system, but to continue operating the fuel cell system 18 in order to feed the minimum possible electrical power to the high-voltage system 11 through the fuel cell system. In this case, an optional brake 20 can be used to exhaust excess electrical power.

[0052] If the power required when adjusting the power to be provided by the fuel cell system in box 31 is greater than the power that the fuel cell system 18 can provide in the highest permissible operating mode, then the power to be provided by the fuel cell system will be adjusted to the maximum power that can be provided.

[0053] Reference Figure 2 and Figure 3 The described method is repeated based on the defined criteria, especially by time control or by event control.

[0054] Therefore, the power distribution between the fuel cell system 18 and the high-voltage energy storage device 15 can be reassessed within a fixed time interval. On the other hand, the assessment of the power distribution can also depend on the presence of defined events, such as changes in travel distance, changes in vehicle parameters, or changes in the speed profile (e.g., due to traffic congestion).

[0055] Figure 4 Showing the target Figure 3 A variant in which the electrical power to be provided by the fuel cell system 18 is adjusted in block 28.

[0056] exist Figure 3 In this process, adjustments are made starting from the foreseeable horizon, initially targeting the sub-cycle until the known state-of-charge curve of the high-voltage energy storage device 15 first lies outside the invariant SOC boundary, and subsequently potentially targeting further sub-cycles. Figure 4In a variant, the power to be provided by the fuel cell system is adjusted as follows: a reference point is determined across the entire foreseeability range at which the deviation in absolute value between the state of charge (SOC) curve of the high-voltage energy storage device 15 and the constant SOC boundary is maximized. Subsequently, the power to be provided by the fuel cell system 18 is adjusted such that, with respect to this reference point, the SOC curve of the high-voltage energy storage device 15 lies within the SOC boundary. This process is then repeated until, preferably, the SOC curve lies within the SOC boundary at all reference points.

[0057] Therefore, in Figure 4 In box 36, the extreme values ​​of the state of charge curve of the high-voltage energy storage device 15 located outside the constant SOC boundary within the entire foreseeability horizon are obtained. Preferably, the reference point that is lowest in absolute value below the lower SOC boundary or the lowest SOC boundary is obtained, and the reference point that is highest in absolute value above the upper SOC boundary or the highest SOC boundary is obtained. Therefore, there are cases where the SOC boundary of the high-voltage energy storage device 15 is exceeded at these reference points. If there are cases of exceeding the constant SOC boundary in both directions, the reference point that occurs first in time is selected in box 37. If there is a case of exceeding the SOC boundary in only one direction (i.e., either below the lower SOC boundary or above the upper SOC boundary), that reference point is selected in box 37.

[0058] Subsequently, in box 38, the power to be provided by the fuel cell system 18 is adjusted for the reference point selected in box 37. In box 38, the power to be provided by the fuel cell system 18 is actually adjusted, wherein if the power to be provided by the fuel cell system 18 should be adjusted because it exceeds the upper boundary of the State of Charge (SOC), the power to be provided by the fuel cell system 18 is reduced. Conversely, if the power to be provided by the fuel cell system 18 needs to be adjusted because it is below the lower boundary of the SOC, the power to be provided by the fuel cell system 18 is increased.

[0059] After adjusting the power to be provided by the fuel cell system 18 in box 38, the updated state of charge curve for the high-voltage energy storage 15 is obtained in box 39, wherein in box 40, it is checked whether the new state of charge curve is within or outside the SOC boundary.

[0060] If the new state of charge curve is confirmed to be outside the SOC boundary in box 40, then return to box 36 from box 40. Conversely, if the new state of charge curve is confirmed to be inside the SOC boundary in box 40, then proceed to box 41, whereby the adjustment of the power to be provided by fuel cell system 18 is completed and then you can return to box 27.

[0061] If it is confirmed in box 36 that there are cases where the SOC boundary is broken in both directions, then first select the reference point that first breaks the SOC boundary in time to perform steps in boxes 38, 39, and 40. Then, select the reference point that breaks the SOC boundary later in time to perform steps in boxes 38, 39, and 40.

[0062] When adjusting the power to be provided by the fuel cell system in box 38, the power to be provided is performed from the beginning of the foreseeability horizon until the reference point determined in box 37. If optimization is to be performed on the end of the foreseeability horizon, the time period is selected to extend to the end of that horizon. The power to be adjusted depends on the difference between the corresponding SOC boundary and the state of charge of the high-voltage energy storage 15 at or above the reference point known in box 37. This difference is divided by the mentioned time period to determine the power adjustment. If the adjusted power of the high-voltage energy storage 15 is lower than the minimum power that can be provided, it is preferable again to decide whether to shut down the fuel cell system 18 or continue operating the fuel cell system while providing the minimum possible power, depending on the expected degree of aging.

[0063] If the adjustment of the power to be provided by the fuel cell system 18 results in exceeding the maximum power that the fuel cell system 18 can provide, then the power to be provided by the fuel cell system 18 will be set to the maximum available power.

[0064] The method according to the invention allows a motor vehicle configured as a fuel cell vehicle to operate with optimal power distribution between the fuel cell system 18 and the high-voltage energy storage 15, taking into account both battery capacity and the permissible, invariant state of charge (SOC) boundary of the high-voltage energy storage 15. This reduces the dynamic load on the fuel cell system 18. It also reduces hydrogen consumption due to the fuel cell system 18. Furthermore, it reduces the risk of damage to both the fuel cell system 18 and the high-voltage energy storage 15.

[0065] The present invention also relates to a control device for a motor vehicle 10 configured as a fuel cell vehicle, the control device being configured to automatically implement the above-described method on the control side. For this purpose, the control device has hardware and software components, wherein the data interface, processor, and memory belong to the hardware components.

[0066] The data interface is used to exchange data with components involved in implementing the method according to the invention, such as motor 12, high-voltage energy storage 15, and fuel cell system 18. The memory is used to store data, and the processor is used to process the data.

[0067] Implementing a program module for executing the method according to the invention in the control device according to the invention is a software-related mechanism.

[0068] List of reference numerals

[0069] 10 Motor vehicles

[0070] 11 High Voltage Systems

[0071] 12 motors

[0072] 13. Drawing electrical power from high-voltage systems

[0073] 14. Feeding power to high-voltage systems

[0074] 15 High-voltage energy storage

[0075] 16. Drawing electrical power from high-voltage systems

[0076] 17. Feeding electrical power to high-voltage systems

[0077] 18. Fuel Cell System

[0078] 19. Feeding power to high-voltage systems

[0079] 20 Brakes

[0080] 21. Drawing electrical power from high-voltage systems

[0081] 22. Define and delineate the foreseeable horizon.

[0082] 23. Obtaining power demand

[0083] 24. Obtain average power demand

[0084] 25. Obtain the charge state curve

[0085] 26. Compare the charge state curve with the SOC boundary.

[0086] 27. Operating the fuel cell system

[0087] 28. Adjust the power of the fuel cell system.

[0088] 29. Obtain the reference point outside the SOC boundary.

[0089] 30. Obtain information about the child's itinerary.

[0090] 31. Adjusting the power of the fuel cell system

[0091] 32. Obtaining the new state-of-charge curve

[0092] 33. Compare the new state-of-charge curve with the SOC boundary.

[0093] 34. End of Foresight

[0094] 35. Obtain further information about the sub-trips.

[0095] 36. Determine the limiting reference point outside the SOC boundary.

[0096] 37. Select the first limiting reference point in time.

[0097] 38. Adjust the power of the fuel cell system.

[0098] 39. Obtaining the new state-of-charge curve

[0099] 40. Compare the new state-of-charge curve with the SOC boundary.

[0100] 41. Complete the power adjustment of the fuel cell system.

Claims

1. A method for operating a motor vehicle (10) configured as a fuel cell vehicle, wherein, The motor vehicle (10) has a high-voltage system (11), a motor (12) serving as a drive unit, an electrical high-voltage energy storage device (15), and a fuel cell system (18), wherein the motor (12) draws electrical power (13) from the high-voltage system (11) in motor-driven operation and feeds electrical power (14) to the high-voltage system (11) in generator-driven operation, wherein the electrical high-voltage energy storage device (15) draws electrical power (16) from the high-voltage system (11) in charging operation and feeds electrical power (17) to the high-voltage system (11) in discharging operation, and wherein the fuel cell system (18) feeds electrical power (19) to the high-voltage system (11) in an active state, the method having the following steps: Regarding the foreseeable horizon, that is, the future journey of the motor vehicle (10), the electrical power requirement of the motor vehicle (10) is determined along a reference point of the foreseeable horizon. From the electric power demand of the motor vehicle (10) known from a reference point relative to the foreseeability horizon, the average power demand of the motor vehicle (10) along the foreseeability horizon is obtained. Assuming that the fuel cell system (18) operates in a constant operating mode along the foreseeable horizon to provide the average power demand, the state-of-charge curve of the high-voltage energy storage device (15) along the foreseeable horizon is obtained, wherein, If the known state of charge curve along the predicted horizon lies within the SOC boundary that remains constant along the predicted horizon, then the fuel cell system (18) is operated to provide the average power demand. If the known state of charge curve along the foreseeability boundary is located outside the SOC boundary that remains unchanged along the foreseeability boundary, the power to be provided by the fuel cell system (18) is adjusted so that the state of charge curve of the high-voltage energy storage device (15) along the foreseeability boundary remains or is located more or more within the SOC boundary that remains unchanged along the foreseeability boundary.

2. The method according to claim 1, characterized in that, When the change in the elevation curve of the total future journey exceeds the boundary value, the journey up to the first high or low point of the total journey is selected as the foreseeable horizon, and / or When the change in the height curve of the total travel is less than the boundary value, a travel of a limited first length is selected as the foreseeability horizon, and / or When the predicted average speed along the total travel distance is less than the boundary value, a travel distance with a defined second length is selected as the foreseeability horizon.

3. The method according to claim 1 or 2, characterized in that, The electric power demand of the vehicle (10) at the reference point is determined by the driving resistance of the vehicle (10) and the secondary power consumption of the vehicle (10) for the foresight horizon.

4. The method according to any one of claims 1 to 3, characterized in that, The average power demand of the motor vehicle (10) along the foreseeability horizon is obtained in such a way that the electric power demand at a reference point of the foreseeability horizon is converted into the power demand of the motor vehicle (10) over time based on the predicted driving speed, and the power demand over time is integrated along the foreseeability horizon and divided by the predicted driving time for the foreseeability horizon.

5. The method according to any one of claims 1 to 4, characterized in that, Assuming that the fuel cell system (18) operates in a constant operating mode along the foreseeability horizon to provide the average power demand, the state of charge curve of the high-voltage energy storage device (15) along the foreseeability horizon is known by relying on the battery power loss and / or on the battery performance as a function of SOC and / or as a function of temperature and / or on the braking resistance.

6. The method according to any one of claims 1 to 5, characterized in that, When the known portion of the state of charge curve along the foreseeability horizon is outside the constant state of charge (SOC) boundary along the foreseeability horizon, in order to adjust the power to be provided by the fuel cell system (18), the power to be provided by the fuel cell system (18) is first adjusted for the sub-stroke along the foreseeability horizon up to a first reference point where the state of charge curve is outside the constant SOC boundary, such that the state of charge curve up to that reference point is within the SOC boundary. Preferably, these steps are then repeated until the state of charge curve is within the SOC boundary for all or as many subsequent sub-strokes as possible.

7. The method according to any one of claims 1 to 5, characterized in that, When the known portion of the state of charge curve along the foreseeability horizon lies outside the constant state of charge (SOC) boundary along the foreseeability horizon, in order to adjust the power to be provided by the fuel cell system (18), firstly, the reference points where the deviation of the state of charge curve from the constant lower or upper SOC boundary along the foreseeability horizon is the largest are determined, wherein the power to be provided by the fuel cell system (18) is then adjusted such that the state of charge curve lies within the SOC boundary with respect to these reference points, wherein preferably, these steps are then repeated until the state of charge of the high-voltage energy storage device (15) lies within the SOC boundary at all or as many reference points as possible.

8. The method according to any one of claims 1 to 7, characterized in that, The method can be repeated either by time control or by event control.

9. Control equipment for operating a motor vehicle (10) configured as a fuel cell vehicle, in, The control device determines the electric power requirement of the vehicle (10) based on a foreseeable horizon, i.e., the future journey of the vehicle, and a reference point along the foreseeable horizon. The control device determines the average power demand of the vehicle along the foreseeability horizon by obtaining the electric power demand of the vehicle (10) from a reference point relative to the foreseeability horizon. Wherein, the control device, assuming that the fuel cell system (18) operates in a constant operating mode along the foreseeable horizon to provide the average power demand, obtains the state-of-charge curve of the high-voltage energy storage along the foreseeable horizon, wherein, If the known state of charge curve along the predicted horizon lies within the SOC boundary that remains unchanged along the predicted horizon, then the control device causes the fuel cell system (18) to operate to provide the average power demand. If the known state of charge curve along the foreseeability boundary is located outside the state of charge (SOC) boundary that remains unchanged along the foreseeability boundary, the control device adjusts the power to be provided by the fuel cell system (18) so that the state of charge curve of the high-voltage energy storage along the foreseeability boundary remains or is located more or more within the state of charge (SOC) boundary that remains unchanged along the foreseeability boundary.

10. The control device according to claim 9, characterized in that, The control device is configured to implement the method according to any one of claims 1 to 8.

Images