Control Device and Method for Controlling a Fuel-Cell-Based Motor Vehicle Drive

Abstract

A control device for controlling an electric motor vehicle drive having an electric drive, a first fuel-cell-based energy source, and a second fuel-cell-free energy source, has a human-machine interface for detecting a user input for selecting an operating mode for the motor vehicle drive and a control unit. The control unit is configured to receive a selection signal from the human-machine interface indicating a user input for selecting an operating mode for the motor vehicle drive and to control the motor vehicle drive in accordance with the selection signal to transfer the same into a first operating mode in which the first energy source is operated to supply the electric drive with electrical energy or to transfer the same into a second operating mode in which the first energy source is deactivated and in which the second energy source is operated to supply the electric drive with electrical energy.

Claims

1. A control device for controlling an electric motor vehicle drive, wherein the electric motor vehicle drive has an electric drive, a first fuel-cell-based electrical energy source, and a second fuel-cell-free electrical energy source, comprising: a human-machine interface, wherein the human-machine interface detects a user entry for selecting an operating mode for the electric motor vehicle drive; and a control unit, wherein the control unit is configured to receive a selection signal from the human-machine interface which indicates the user entry and to control the electric motor vehicle drive in accordance with the selection signal in order to: transfer the electric motor vehicle drive into a first operating mode in which the first fuel-cell-based electrical energy source is operated in order to feed the electric drive with electrical energy; or transfer the electric motor vehicle drive into a second operating mode in which the first fuel-cell-based electrical energy source is deactivated and is in a secure state and in which the second fuel-cell-free electrical energy source is operated in order to feed the electric drive with electrical energy.

2. The control device as claimed in claim 1, wherein the control unit is further configured to, in accordance with the selection signal, control the electric motor vehicle drive in order to transfer the electric motor vehicle drive into a third operating mode in which the electric drive is not fed by the first fuel-cell-based electrical energy source nor the second fuel-cell-free electrical energy source and the first fuel-cell-based electrical energy source is operated to supply the second fuel-cell-free electrical energy source with electrical energy.

3. The control device as claimed in claim 1, wherein the control unit is further configured to control the electric motor vehicle drive in the second operating mode such that a power consumption of the electric drive is kept under a predetermined power threshold which is under a maximum energy supply power of the second fuel-cell-free electrical energy source.

4. The control device as claimed in claim 1, wherein the control device is further configured to output a currently selected operating mode by the human-machine interface.

5. The control device as claimed in claim 1, wherein the control unit is further configured to: determine, while the second operating mode is activated, if an available energy content to feed the electric drive remaining in the second fuel-cell-free electrical energy source has reached a predetermined threshold or has fallen below the predetermined threshold and, if determined that the available energy content has reached the predetermined threshold or has fallen below the predetermined threshold, output a notification on the human-machine interface and make available a selection option for a change into another operating mode in which the second fuel-cell-free electrical energy source does not act as an energy supplier.

6. The control device as claimed in claim 1, wherein the control device is further configured to: generate or receive position data which indicates a current position of a motor vehicle in which the electric motor vehicle drive is disposed; based on electronic map material and the position data, identify a traffic area that cannot be driven on in an active fuel-cell mode; determine if the current position has approached the identified traffic area according to a predetermined criterion; and if determined, output a notification on the human-machine interface.

7. The control device as claimed in claim 1, wherein the control device is further configured to detect a motor-start or a motor-stop entry on the human-machine interface and to respectively start or stop the electric drive manually or automatically.

8. An electric motor vehicle drive, comprising: the control device as claimed in claim 1; an electric drive with an electric traction motor; a first fuel-cell-based electrical energy source for feeding the electric drive with electrical energy; a second fuel-cell-free electrical energy source for feeding the electric drive with electrical energy; and a safety device, wherein the safety device keeps the first fuel-cell-based electrical energy source in a deactivated and secure state.

9. The electric motor vehicle drive as claimed in claim 8, wherein the safety device has a safety valve which interrupts a fuel supply to the first fuel-cell-based electrical energy source if the electric motor vehicle drive is in the second operating mode.

10. A method for controlling an electric motor vehicle drive, wherein the electric motor vehicle drive has an electric drive, a first fuel-cell-based electrical energy source, and a second fuel-cell-free electrical energy source, comprising the acts of: detecting, on a human-machine interface, a user entry for selecting an operating mode for the electric motor vehicle drive; receiving a selection signal from the human-machine interface which indicates the user entry by a control unit; and controlling the electric motor vehicle drive by the control unit in accordance with the selection signal in order to: transfer the electric motor vehicle drive into a first operating mode in which the first fuel-cell-based electrical energy source is operated in order to feed the electric drive with electrical energy; or transfer the electric motor vehicle drive into a second operating mode in which the first fuel-cell-based electrical energy source is deactivated and is in a secure state and in which the second fuel-cell-free electrical energy source is operated in order to feed the electric drive with electrical energy.

11. The method as claimed in claim 10, further comprising the act of: controlling the electric motor vehicle drive by the control unit in accordance with the selection signal in order to transfer the electric motor vehicle drive into a third operating mode in which the electric drive is not fed by the first fuel-cell-based electrical energy source nor the second fuel-cell-free electrical energy source and the first fuel-cell-based electrical energy source is operated to supply the second fuel-cell-free electrical energy source with electrical energy.

12. The method as claimed in claim 10, wherein, in the second operating mode, the electric motor vehicle drive is controlled such that a power consumption of the electric drive is kept under a predetermined power threshold which is under a maximum energy supply power of the second fuel-cell-free electrical energy source.

13. The method as claimed in claim 10 further comprising the act of outputting a currently selected operating mode by the human-machine interface.

14. The method as claimed in claim 10 further comprising the acts of: determining, while the second operating mode is activated, if an available energy content to feed the electric drive remaining in the second fuel-cell-free electrical energy source has reached a predetermined threshold or has fallen below the predetermined threshold; and if determined that the available energy content has reached the predetermined threshold or has fallen below the predetermined threshold, outputting a notification on the human-machine interface and making available a selection option for a change into another operating mode in which the second fuel-cell-free electrical energy source does not act as an energy supplier.

15. The method as claimed in claim 10 further comprising the acts of: generating or receiving position data which indicates a current position of a motor vehicle in which the electric motor vehicle drive is disposed; based on electronic map material and the position data, identifying a traffic area that cannot be driven on in an active fuel-cell mode; determining if the current position has approached the identified traffic area according to a predetermined criterion; and if determined, outputting a notification on the human-machine interface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0039] FIG. 1 is a schematic representation of a motor vehicle drive according to one preferred embodiment of the invention.

[0040] FIG. 2 is a flow chart to illustrate a preferred embodiment of the method according to the invention.

[0041] FIG. 3 is a flow chart to illustrate a preferred embodiment of an optional process as part of the method according to the invention that serves to control the motor vehicle drive in the second fuel-cell-free operating mode.

[0042] FIG. 4 is a flow chart to illustrate a preferred embodiment of an optional navigation process as part of the method according to the invention that serves to control the motor vehicle drive in the second fuel-cell-free operating mode.

DETAILED DESCRIPTION OF THE DRAWINGS

[0043] In the following Figures, the same reference numbers are consistently used for the same elements of the invention or elements of the invention that correspond to each other.

[0044] Initially, reference is made to FIG. 1. There, a motor vehicle drive 1 in accordance with a preferred embodiment of the invention is shown. The motor vehicle drive 1 has a control device 2, a fuel-cell-based first energy source 7, a fuel-cell-free second energy source 8, an electric drive 9 as well as a control unit 10 to control the electric drive 9. The first energy source 7 is supplied with fuel from a fuel tank 11, which can be supplied by a fuel line 12, in particular, for hydrogen. On both ends of the fuel line 12, there are safety valves 13a and 13b, with which the fuel supply to the first energy source 7 can be interrupted. The fuel tank 11 can also be implemented in the form of a tank system made up of a plurality of individual tanks, which can, in particular, be designed to operate at temperatures and/or pressures that are different from each other. The control device 2 contains a human-machine interface 4, which, in turn, has a display device 5, in particular, to display notifications and display the current operating mode of the motor vehicle drive 1 as well as a switch combination 6. As a first operating element, the switch combination 6 has a start-stop switch 6a, which serves to start or to stop the motor vehicle drive 1. In addition, as another entry element, an operating mode switch 6b is arranged, by means of which one of three available operating modes B1, B2, B3 for the motor vehicle drive 1 can be respectively selected. The operating mode switch 6b has three different entry options accordingly, which can be particularly implemented by pressing for various lengths of time, by means of various snap-in positions or other activation options of the operating mode switch 6b. In addition, the switch combination 6, preferably on the operating mode switch 6b, has a display element 6c, which can be used in particular to signal a switch position, for example, by means of various light signals, which can vary from each other in color, how they blink, etc. The control device 2 furthermore has a control unit 3, which is connected to the human-machine interface 4 via a communications link as well as via a switch device made up of two switches 14 and 15 here as an example, which can be controlled by means of the control unit 3 (controls are shown here by means of dashed links) in order to be set into various switching states. The switch 14 serves to connect the electric drive 9 to the first energy source 7 (switch position a) or the second energy source (switch position c) depending on the operating mode B1, B2, or B3 of the motor vehicle drive 1 selected, or, however, to electrically decouple the electric drive 9 from both energy sources 8, 9 (switch position b). The second switch 15 can be implemented as a simple ON/OFF switch, with which an electrical connection between the first and the second energy source can be disconnected or established. In the first operating mode B1, the switch 14 is in switch position a so that the electric drive 9 is supplied with electrical energy from the fuel-cell-based first energy source 7. Simultaneously, the switch 15 is opened. In contrast, in the second operating mode B2, the switch 14 is in switch position c so that the electric drive 9 is now supplied with electrical energy from the fuel-cell-free second energy source 8. In turn, here, the switch 15 is also opened. In the third operating mode B3, which can be referred to as the stationary charging mode, the switch 14 is in the open switch position b, in which it does not couple the first nor the second energy source to the electric drive 9. The electric drive 9 is therefore deactivated and thereby de-energized in this operating mode. Now, however, the switch 15 is closed so that the first energy source 7 can be operated in order to charge the second energy source 8, which is designed as an accumulator, in particular a lithium-ion cell-based accumulator, by means of the closed connection established by the switch 15. By means of a corresponding control by the control unit 3, the safety valves 13a and 13b are shut in the third operating mode B3 so that the first energy source is in a secure state, in which the fuel supply from the fuel tank 11 is interrupted. In particular, by means of the safety valve 13a, the output of the fuel tank 11 is also sealed so that this as well as the fuel line 12 are also in a secure state.

[0045] Now, reference is made to FIG. 2. There, a preferred embodiment of the method according to the invention is shown, which should now be explained, thereby making reference to the motor vehicle drive in FIG. 1 as an example.

[0046] In a first step S0 on the start-stop switch 6a, the method begins with a user entry, by means of which the motor vehicle drive 1 is started. In another step S1, the current operating mode B1, B2 or B3 is output on the human-machine interface 4 according to the setting of the last entry(ies) on the operating mode switch 6b, in particular, displayed on the display device 5. As an alternative to this, a certain operating mode can also be defined as a standard operating mode, which is activated independently of the last operating mode or a certain setting of the operating mode switch 6b when starting the motor vehicle drive 1. In particular, this is useful if the operating mode switch 6b does not have any different fixed switch positions so that its original state is always the same at the beginning of the method. The latter can particularly be the case if the various operating modes can be selected solely by a pressing on the operating mode switch 6b for various periods of time without this remaining in a certain setting, in particular, snapping into it.

[0047] In another step S2, a user entry to select an operating mode for the motor vehicle drive 1 is detected on the human-machine interface 4. Simultaneously, in parallel to this, an optional navigation process S8 is started, which will be explained in detail in the following making reference to FIG. 4.

[0048] In another step S3, a verification is made of if another user entry to stop the motor vehicle drive 1 has taken place by means of the start-stop switch 6a. If this is the case, the method is terminated. Otherwise, the method goes on to step S4, in which it is determined, which operating mode the user entry that took place at step S2 corresponds to. If this user entry corresponds to an entry to select a first operating mode B1, the motor vehicle drive 1 is transferred into this first operating mode B1, whereby, in particular, the switch 14 is set to switch position a and the switch 15 is opened. In contrast, if the user entry corresponds to a selection of a second operating mode B2, in step S6, a transfer of the motor vehicle drive 1 into this second operating mode B2 takes place, whereby, in particular, the switch 14 is set to switch position c and the switch 15 is opened. In contrast, if the user entry corresponds to a selection of the third operating mode B3, in step S7, the motor vehicle drive is transferred into this third operating mode B3, whereby, in particular, the switch 14 is set to switch position b and the switch 15 is closed.

[0049] In FIG. 3, a preferred embodiment of an optional process is shown as part of the method in FIG. 2, which serves to control the motor vehicle drive in the second fuel-cell-free operating mode B2. The method steps shown in FIG. 3 represent substeps of the method step S6 in FIG. 2 according to this. In a first substep S6-1, it is checked if the energy content E.sub.2 of the second energy source is greater than a predetermined minimum amount of energy E.sub.min. If this is the case (S6-1; yes) so that the second energy source still has sufficient energy to continue to power the motor vehicle drive 1, the method proceeds to substep S6-3, otherwise (S6-1; no), it is branched off into another substep S6-2. In substep S6-2, on the human-machine interface, a notification is output, by means of which the driver or the user are signaled that the second operating mode will soon no longer be available and then it proceeds to substep S6-3. In substep S6-3, it is checked if the power consumption of the electric drive 9 is under a predetermined power threshold P.sub.max. If that is the case (S6-3; yes), in accordance with FIG. 2, step S1 is branched back to. Otherwise (S6-3; no) the power supplied to the electric drive is still reduced beforehand, in particular, by means of a gradual reduction. In parallel to branching back to step S1, the process shown in FIG. 3 is continued until the end of the second operating mode B2 in a loop-like manner.

[0050] FIG. 4 shows an optional navigation process S8, as shown in FIG. 1, in greater detail in accordance with a preferred embodiment. Thereby, position data that indicate a current position of the vehicle equipped with the motor vehicle drive 1, are generated by the control unit itself in a first substep S8-1 or are received by a position determination device, in particular, one that is external to the drive. In another substep S8-2, electronic map data are received and based upon these data, one or a plurality of traffic areas are identified, which cannot be driven on using a gas or fuel-cell drive according to the map data. Receiving the electronic map data can also alternatively take place at the same time as the position data is received in step S8-1. In a subsequent step S8-3, a verification is made of if the current position has approached one of the traffic areas identified during step S8-2 in accordance with a predetermined criterion, in particular, a distance criterion, such as a remaining stretch of road or a geometrical distance. If this is not the case (S8-3; no), the process branches back to the substep S8-1. Otherwise (S8-3; yes), i.e., if such an approach has been determined during step S8-3, an output of a corresponding notification for the driver takes place on the human-machine interface 4, thereby indicating that a corresponding traffic area is located in the proximity or, in particular, will soon be driven on so that the driver is reminded to switch into another permissible operating mode, in particular, into the operating mode B2, in a timely manner prior to driving on the traffic area. The process S8 is continuously repeated and runs in parallel to the main process in accordance with FIG. 2.

[0051] While, in the preceding, at least one exemplary embodiment has been described, it must be noted that a great number of variations concerning this exist. Thereby, it must also be noted that the described exemplary embodiments only represent non-limiting examples, and is not intended by means of this to limit the scope, the applicability or the configuration of the devices and methods described here. Rather, the preceding description should provide the person skilled in the art with instructions for the implementation of at least one exemplary embodiment, wherein it is understood that various changes in the function and arrangement of the elements described in an exemplary embodiment can be performed without deviating from the subject respectively defined in the enclosed claims as well as the legitimate equivalents thereof.

REFERENCE LIST

[0052] 1 motor vehicle drive [0053] 2 control device [0054] 3 control unit [0055] 4 human-machine interface [0056] 5 display device [0057] 6 switch combination [0058] 6a start-stop switch [0059] 6b operating mode switch [0060] 6c display element [0061] 7 first fuel-cell-based energy source [0062] 8 second fuel-cell-free energy source [0063] 9 electric drive [0064] 10 control device for electric drive [0065] 11 fuel tank for first energy source [0066] 12 fuel line [0067] 13a, b safety valves [0068] 14 first switch [0069] 15 second switch

[0070] The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.