Method for operating a motor vehicle and corresponding motor vehicle

Abstract

The invention relates to a method for operating a motor vehicle (1), wherein the motor vehicle (1) comprises a drive device (3) and a plurality of x-by-wire control devices (6). According to the invention, a central processing unit (9) of the motor vehicle (1) determines an overall status from status messages transmitted by the control devices (6), and actuates the drive device (3) and / or the control devices (6) on the basis of the overall status. The invention also relates to a motor vehicle (1).

Description

[0001] Method for operating a motor vehicle and corresponding motor vehicle

[0002] DESCRIPTION:

[0003] The invention relates to a method for operating a motor vehicle, wherein the motor vehicle has a drive device and a plurality of X-by-wire control devices. The invention further relates to a motor vehicle.

[0004] For example, DE 197 35 018 A1 is known from the prior art. This describes a system architecture for implementing functions in a motor vehicle, comprising at least two X-by-Wire systems whose control units are connected to each other directly or via a bus structure.

[0005] Furthermore, the document DE 197 10 082 A1 describes a drive system for commercial vehicles, in particular for agricultural or industrial tractors, which includes a generator driven by an internal combustion engine, at least one drive axle, the wheels of which are each driven by an associated electric motor fed by the generator, at least one steering axle, the wheels of which are steered jointly or individually by steering actuators, and manual control elements for at least the driving functions of steering and speed setting.

[0006] Furthermore, WO 99 / 39950 A1 discloses a method for controlling or regulating the braking system of a vehicle according to the break-by-wire principle, which comprises a brake pedal with a pedal mechanism and a pedal sensor system, an electronic evaluation unit, and wheel brake modules. The method comprises the following steps: detecting the driver's brake pedal actuation using at least two measuring devices that determine variables characterizing the brake pedal actuation; and determining the driver's braking request from the signals from the measuring devices in the electronic evaluation unit. The measuring devices determine the same variable characterizing the brake pedal actuation to determine the braking request, and a further measured variable for monitoring the pedal mechanism and the pedal sensor system is derived and compared with the braking request signal in the electronic evaluation unit.

[0007] The object of the invention is to propose a method for operating a motor vehicle which has advantages over known methods, in particular always enables reliable and safe operation of the motor vehicle even with X-by-wire control devices without a mechanical fallback level.

[0008] This is achieved according to the invention with a method for operating a motor vehicle having the features of claim 1. It is provided that a central computer of the motor vehicle determines an overall status from status messages transmitted by the control devices and controls the drive device and / or the control devices based on the overall status.

[0009] Advantageous embodiments with useful further developments of the invention are specified in the dependent claims. It should be noted that the exemplary embodiments explained in the description are not limiting; rather, any variations of the features disclosed in the description, the claims, and the figures are feasible.

[0010] The method serves to operate the motor vehicle. The motor vehicle has the drive device and the X-by-wire control devices. The drive device serves to drive the motor vehicle, thus providing a drive torque directed towards driving the motor vehicle. To provide the drive torque, the drive device has at least one drive unit, for example an internal combustion engine or an electric traction machine. Of course, the drive device can also have multiple drive units which jointly provide the drive torque at least temporarily. In this case, the drive units are preferably of different types; for example, one of the drive units is an internal combustion engine and another of the drive units is an electric traction machine.

[0011] Furthermore, the motor vehicle has several X-by-wire control devices. These are control devices that are controlled exclusively electrically, i.e., have no mechanical fallback level. The X-by-wire control devices include, for example, one or more brake-by-wire control devices, one or more steer-by-wire control devices, and / or one or more shift-by-wire control devices. The control devices can be directed toward braking, steering, or gear shifting, or can perform such operations at least temporarily.

[0012] The brake-by-wire control systems are used for braking, the steer-by-wire control systems for steering, and the shift-by-wire control systems for gear shifting. Each brake-by-wire control system comprises one or more wheel brakes with brake actuators that are controlled purely electronically. The steer-by-wire control systems each have a steering actuator that can be used to adjust the steering angle of the vehicle and are also controlled exclusively electronically.

[0013] Finally, the shift-by-wire control device includes a shift actuator located in a manual transmission of the motor vehicle. The manual transmission serves to set a gear selected from several different gears or a corresponding gear ratio between the drive unit or one of the drive units and at least one driven wheel of the motor vehicle. The shift actuator is provided and designed to set the selected gear or gear ratio on the manual transmission. The shift actuator is also controlled purely electronically.

[0014] Each of the X-by-Wire control devices is intended and designed to influence the driving operation of the motor vehicle, for example, for braking, steering, or gear shifting. Each of the control devices has, for example, an operating element that is arranged in a passenger compartment of the motor vehicle and that is operatively connected to an actuator of the motor vehicle purely electronically, i.e., without a mechanical fallback level. Control devices of the same type can, of course, use the same operating element. The brake-by-wire control devices are thus jointly controlled by means of a brake operating device, in particular a brake pedal. The steer-by-wire control devices have a common steering operating device, in particular a common steering wheel or the like. The actuator is, for example, the wheel brake or one of the wheel brakes, the steering actuator, or the gearshift actuator.

[0015] In conventional motor vehicles, a mechanical connection is always available between the respective control element and the respective actuator, at least as a fallback. Electronic control of the respective actuator can also be provided; for example, a brake booster, power steering, or the like can be electrically operated. This means that even in the event of a power failure, the vehicle can be reliably operated via the mechanical fallback, although this may require greater force.

[0016] However, the motor vehicle underlying the method according to the invention has several X-by-wire control devices, which do not have such a mechanical fallback level. Nevertheless, the driving operation of the motor vehicle should be carried out reliably and safely. For this reason, each of the control devices transmits a status message to the central computer at least temporarily. Preferably, the status messages are transmitted from the respective control device to the central computer periodically or permanently. In the case of periodic transmission, the interval between successive transmissions of the status message is dimensioned such that, even in the event of a sudden malfunction, the central computer can initiate countermeasures in a timely manner to ensure the safety of the motor vehicle.

[0017] The central processing unit is preferably separate from the control units, thus representing an additional unit of the motor vehicle. The central processing unit and the control units are connected to one another for communication purposes, in particular via a bus system, for example via a CAN bus or Flexray bus. However, it can also be provided that one of the control units comprises the central processing unit or assumes its tasks. In this case, however, the control unit and the central processing unit are formed by different circuits, so that a defect in the control unit does not also mean a defect in the central processing unit. The central processing unit is particularly preferably a component of a control unit of the drive unit, which can also be referred to as an engine control unit.In this case, it is ensured that if the central computer is defective, the engine control unit is inoperable and the drive system is therefore out of operation.

[0018] The central processing unit receives the status messages transmitted by the control units and uses them to determine the overall status. This means that the overall status depends on all status messages transmitted by the control units. The absence of status messages from one or more of the control units can also influence the overall status. The overall status is therefore a function of the status messages. The overall status describes the overall state of the multiple X-by-wire control units and, consequently, the technical equipment of the motor vehicle. The central processing unit controls the drive unit and / or the control units based on the overall status, in particular to influence the driving operation of the motor vehicle.This preferably means that the central computer transmits a control command to the drive device and / or the control devices, which depends on the overall status.

[0019] The drive device and / or the control devices are in turn controlled depending on the transmitted control command. Based on the control command, for example, activation of the drive device is permitted or prevented, or the drive device is deactivated. It can also be provided that one of the control devices is controlled based on the control command to influence the driving operation of the motor vehicle, for example, for braking, steering, or gear shifting.

[0020] The central computer, which can also be referred to as a central coordinator, serves to collect and summarize the status messages for the overall status and to control at least one device of the motor vehicle, namely the drive device and / or the control devices. This implements central control of the motor vehicle to ensure its safety at all times. Furthermore, the central computer can be used to create a consistent display for the user of the motor vehicle, which is not based on the individual status messages, but rather on the overall status. This avoids the display of different status messages from the control devices, which can be confusing for the user. Overall, safe and consistent operation of the motor vehicle is achieved.

[0021] A further development of the invention provides that each of the control devices performs a self-diagnosis and, based on the result of the self-diagnosis, determines a control device status and / or a remaining running time of the motor vehicle, which is transmitted to the central computer as part of the respective status message. The remaining running time is, in particular, a remaining running time or a remaining running distance. The remaining running time describes the still permissible driving time, and the remaining running distance describes the still permissible driving distance. The self-diagnosis serves to determine the status of the respective control device. If it is determined during the self-diagnosis that the respective control device can be operated properly, this is recorded as part of the control device status and transmitted to the central computer as a status message.However, if the self-diagnosis determines that there is an error in the respective control device, the error is recorded in the control device status.

[0022] Additionally or alternatively, the remaining running time of the motor vehicle is determined, which is permissible when the fault is present, for example due to legal requirements. The remaining running time is read from a table in which it is stored, for example, depending on the fault or the control device status. The control device status and / or the remaining running time are then transmitted to the central computer in the form of a status message. The remaining running time, in particular the remaining running time or the remaining distance, is measured from the first occurrence of the fault or begins to run from this point in time. This procedure ensures that the status messages transmitted by the control devices always reflect the actual states of the control devices.For this purpose, the self-diagnosis of each of the control devices is preferably carried out at least before the activation of the drive device, but particularly preferably additionally periodically or permanently after the activation of the drive device.

[0023] A further development of the invention provides that the control devices are supplied with electrical power by means of a power supply device, wherein the power supply device performs a self-diagnosis and, based on the result of the self-diagnosis, determines a power supply device status and / or a further remaining running value of the motor vehicle, which is transmitted to the central processing device as part of a further status message, wherein the central processing device takes the further status message into account when determining the overall status. The power supply device serves to supply the control devices with electrical power. In the event of a failure of the power supply device, the control devices are no longer supplied with electrical power and are therefore no longer functional.

[0024] The power supply device's self-diagnosis is performed analogously to the procedure for the control devices. The result of the self-diagnosis is summarized in the power supply device status or the additional remaining running time and communicated to the central processing device as an additional status message. Similar to the remaining running time, the additional remaining running time is preferably an additional remaining running time or an additional remaining distance. The central processing device receives the additional status message and takes it into account when determining the overall status. In particular, the overall status is based on the power supply device status and / or the additional remaining running time of the motor vehicle. The additional remaining running time describes the time for which the motor vehicle can be operated safely based on the result of the self-diagnosis. In particular, legal requirements are taken into account here.Incorporating the result of the power supply device's self-diagnosis into determining the overall status enables a particularly reliable and comprehensive diagnosis of the motor vehicle.

[0025] A further development of the invention provides that the overall status comprises an overall state determined based on the control device states and / or the power supply device state, and / or that the overall status comprises an overall remaining runtime variable determined based on the remaining runtime variables and / or the additional remaining runtime variable. The overall status therefore contains the overall state, the overall remaining runtime variable, or both. The overall state is determined from the control device states and, optionally, the power supply device state. Analogously, the overall remaining runtime variable is determined from the remaining runtime variables of the control devices and, optionally, the additional remaining runtime variable of the power supply device.

[0026] For example, the overall status is only set to a first value that corresponds to full functionality of the motor vehicle if the control device statuses and / or the power supply device status indicate full functionality of the respective device. As soon as one of the control device statuses and / or the power supply device status indicates a fault in the respective device, the overall status is set to a second value that indicates a fault. The overall remaining running time is preferably set to the shortest of the remaining running times and / or the further remaining running time. This ensures that reliable and safe operation of the motor vehicle can take place over the entire remaining running time. The overall remaining running time is measured from the first occurrence of a fault in one of the devices or begins to run from this time.

[0027] A further development of the invention provides that the overall state is set to a first overall state value if the control device states have values ​​that correspond to functional control devices and / or the power supply device state has a value that corresponds to a functional power supply device, and / or that the overall state is set to a second overall state value if one of the control device states has a value that corresponds to a non-functional control device and / or the power supply device state has a value that corresponds to a non-functional power supply device. This has already been discussed. In this respect, the overall state only has the first overall state value if all control device states or the power supply device state indicate the functionality of the respective device.Conversely, the overall state is set to the second overall state value if only one of the control device states and / or the power supply device state has a value indicating a non-functional device. Consequently, a high level of safety for the motor vehicle is achieved.

[0028] A further development of the invention provides that the total remaining running time is set to the smallest value of the remaining running time values ​​and / or the additional remaining running time values. This has also been mentioned above. Using the smallest value for the total remaining running time has the particular advantage that the motor vehicle user is always shown the remaining running time over which the motor vehicle can still be operated reliably and safely.

[0029] A further development of the invention provides that the self-diagnosis of the control devices and the transmission of the status messages to the central computer device take place when the drive device is deactivated and activation of the drive device is only permitted if the determined overall state corresponds to the first overall state value and / or the overall remaining running time has not yet expired, and / or that the self-diagnosis of the control devices and the transmission of the status messages to the central computer device take place when the drive device is activated and the drive device and / or the control devices are controlled to stop the motor vehicle if the determined overall state corresponds to the second overall state value and / or the overall remaining running time has expired.

[0030] The self-diagnosis of the control devices and the transmission of status messages occur when the drive system is deactivated, when the drive system is activated, or when both the drive direction and the drive system are deactivated. A deactivated drive system means that the drive system is not prepared to provide drive torque. For a deactivated internal combustion engine, for example, the ignition and / or fuel supply are interrupted. In particular, the internal combustion engine's speed is zero. For a deactivated electric traction machine, for example, the supply of electrical energy to the traction machine, in particular its power electronics, is interrupted.When the drive system is activated, it is prepared to provide the drive torque, i.e., the internal combustion engine is started and has a rotational speed other than zero; the electric traction motor or its power electronics is supplied with electrical current.

[0031] If the drive device is deactivated, its activation is only permitted if the overall status indicates that proper operation of the control devices or the power supply device is possible and, consequently, the overall status has the first overall status value and / or the overall remaining operating time has not yet expired. If the overall status does not have the first overall status value or if the overall remaining operating time has expired, activation of the drive device is prevented.

[0032] Additionally or alternatively, the described procedure is applied when the drive device is activated. If in this case the overall state does not have the first overall state value and / or the total remaining running time has expired, the drive device and / or the control devices are activated to stop the motor vehicle. Otherwise, continuation of the ferry operation is permitted. Such a procedure has the advantage that starting of the motor vehicle is not permitted if one of the control devices is defective, or that the ferry operation of the motor vehicle is terminated immediately or with a time delay when the defect occurs. This achieves a high level of safety for the motor vehicle. A further development of the invention provides that several of the following devices are used as control devices: brake-by-wire control device, steer-by-wire control device and shift-by-wire control device.The different control devices have already been mentioned. The control devices preferably comprise a plurality of brake-by-wire control devices and / or a plurality of steer-by-wire control devices and / or a plurality of shift-by-wire control devices, each of which is designed to be redundant with respect to one another. Each of the plurality of brake-by-wire control devices is provided and designed to brake the same wheel(s) of the motor vehicle. Analogously, each of the steer-by-wire control devices is provided and designed to adjust the steering angle of the motor vehicle. The plurality of shift-by-wire control devices are provided and designed to operate the same gearshift transmission. The redundant design of the control devices achieves a high level of safety for the motor vehicle.

[0033] A further development of the invention provides that the overall status is displayed to a user of the motor vehicle by means of a display device. The display device is, for example, a visual, acoustic, and / or haptic display device. For example, the overall condition and / or the total remaining mileage of the motor vehicle are displayed to the user. Using the overall status for the display device has the advantage of providing a uniform and consistent display to the user. This avoids the display of individual status messages from the control devices, which can be inconsistent and confusing for the user.

[0034] The invention further relates to a motor vehicle, in particular for carrying out the method according to the explanations in the context of this description, wherein the motor vehicle has a drive device and a plurality of X-by-wire control devices. A central processing device of the motor vehicle is provided and configured to determine an overall status from status messages transmitted by the control devices and to control the drive device and / or the control devices based on the overall status.

[0035] The advantages of such a motor vehicle design and such a procedure have already been pointed out. Both the motor vehicle and the method for its operation can be further developed in accordance with the explanations in this description, so reference is made to these in this regard.

[0036] The features and feature combinations described in the description, in particular the features and feature combinations described in the following description of the figures and / or shown in the figures, can be used not only in the respective combination specified, but also in other combinations or on their own, without departing from the scope of the invention. Thus, embodiments are also considered to be encompassed by the invention that are not explicitly shown or explained in the description and / or the figures, but which follow from or can be derived from the explained embodiments.

[0037] The invention will be explained in more detail below with reference to the exemplary embodiments shown in the drawings, without limiting the invention.

[0038] Figure 1 is a schematic representation of a motor vehicle having a drive device and several X-by-wire control devices.

[0039] Figure 1 shows a schematic representation of a motor vehicle 1. The motor vehicle 1 has a display device 2, which is arranged in an interior, in particular in a passenger compartment, of the motor vehicle 1. The display device 2 is preferably located on a dashboard of the motor vehicle 1. The motor vehicle 1 also has a drive device 3 and a driver assistance device 4. Furthermore, a power supply device 5 and several X-by-wire control devices 6 are part of the motor vehicle. Several of the control devices 6 are present as brake-by-wire control devices 7 and several as steer-by-wire control devices 8. The control devices 6 are therefore designed redundantly.

[0040] The control devices 6 and the power supply device 5 each perform a self-diagnosis and transmit the result of this self-diagnosis as part of a status message to a central processing device 9, which is also a component of the motor vehicle 1. The central processing device 9 determines an overall status from the individual status messages of the control devices 6 and the power supply device 5 and controls the drive device 3 and / or the control devices 6 depending on the overall status. Furthermore, it can be provided to display the overall status to a user of the motor vehicle 1 by means of the display device 2.

[0041] The control is carried out in such a way that the drive device 3 is either enabled for activation or activation is prevented depending on the overall status. Activation is understood to mean preparing for the provision of a drive torque directed towards driving the motor vehicle. If the activation of the drive device 3 is prevented, it cannot provide the drive torque, so that the motor vehicle 1 remains stationary. If the motor vehicle 1 is already in motion, it can be provided, depending on the overall status, to control the driver assistance device 4 to brake the motor vehicle 1. For this purpose, the driver assistance device 4, in turn, controls the corresponding control devices 6, more precisely the brake-by-wire control devices 7.Preferably, not just one of the brake-by-wire control devices 7, but several, in particular all, of the brake-by-wire control devices 7 are activated to brake the vehicle 1. This ensures reliable operation of the motor vehicle 1. LIST OF REFERENCE SYMBOLS:.

[0042] 1 motor vehicle

[0043] 2 Display device 3 Drive device

[0044] 4 Driver assistance system

[0045] 5 Power supply device

[0046] 6 X-by-Wire control device

[0047] 7 Brake-by-wire control device 8 Steer-by-wire control device

[0048] 9 Central computer

Claims

PATENT CLAIMS:

1. Method for operating a motor vehicle (1) wherein the motor vehicle (1) has a drive unit (3) and several X-by-Wire control units (6), characterized in that a central computing unit (9) of the motor vehicle (1) determines an overall status from status messages transmitted by the control units (6) and controls the drive unit (3) and / or the control units (6) on the basis of the overall status.

2. Method according to claim 1, characterized in that each of the control units (6) performs a self-diagnosis and, based on a result of the self-diagnosis, determines a control unit state and / or a residual running quantity of the motor vehicle (1), which is transmitted to the central computing unit (9) as part of the respective status message.

3. Method according to one of the preceding claims, characterized in that the control devices (6) are supplied with electrical current by means of a power supply device (5), wherein the power supply device (5) performs a self-diagnosis and, based on a result of the self-diagnosis, determines a power supply device state and / or a further remaining running quantity of the motor vehicle (1), which is transmitted to the central computing device (9) as part of a further status message, wherein the central computing device (9) takes the further status message into account when determining the overall status.

4. Method according to one of the preceding claims, characterized in that the overall status comprises an overall state which is determined on the basis of the control device states and / or the power supply device state, and / or that the overall status comprises an overall remaining runtime value which is determined on the basis of the remaining runtime values ​​and / or the further remaining runtime value.

5. Method according to one of the preceding claims, characterized in that the overall state is set to a first overall state value if the control device states have values ​​corresponding to functioning control devices (6), and / or the power supply device state has a value corresponding to a functioning power supply device (5), and / or that the overall state is set to a second overall state value if one of the control device states has a value corresponding to a non-functional control device (6), and / or the power supply device state has a value corresponding to a non-functional power supply device (5).

6. Method according to one of the preceding claims, characterized in that the total residual running size is set to the smallest value of the residual running sizes and / or the further residual running size.

7. Method according to one of the preceding claims, characterized in that the self-diagnostics of the control units (6) and the transmission of the status messages to the central computing unit (9) take place when the drive unit (3) is deactivated and activation of the drive unit (3) is only permitted if the determined overall state has the first overall state value and / or the total remaining running time has not yet expired, and / or that the self-diagnostics of the control units (6) and the transmission of the status messages to the central computing unit (9) take place when the drive unit (3) is activated and the drive unit (3) and / or the control units (6) are activated to stop the motor vehicle (1) if the determined overall state has the second overall state value and / or the total remaining running time has expired.

8. Method according to one of the preceding claims, characterized in that several of the following are used as control devices (6). The following devices are used: Brake-by-Wire control device (7), Steer-by-Wire control device (8) and Shift-by-Wire control device.

9. Method according to one of the preceding claims, characterized in that the overall status is displayed to a user of the motor vehicle (1) by means of a display device (2).

10. Motor vehicle (1), in particular for carrying out the method according to one or more of the preceding claims, wherein the motor vehicle (1) has a drive unit (3) and several X-by-Wire control units (6), characterized in that a central computing unit (9) of the motor vehicle (1) is provided and configured to determine an overall status from status messages transmitted by the control units (6) and to control the drive unit (3) and / or the control units (6) on the basis of the overall status.

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