Energy demand of vehicle and / or method for reducing energy usage
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- ROBERT BOSCH GMBH
- Filing Date
- 2023-08-24
- Publication Date
- 2026-07-01
Smart Images
Figure 00000000_0000_ABST
Abstract
Description
[Technical field]
[0001] Prior Art The present invention relates to a method for reducing the energy demand and / or energy usage of a vehicle. Furthermore, the invention relates to a computing unit for implementing such a method and to a vehicle equipped with such a computing unit. [Background technology]
[0002] From the prior art, vehicles are known with conventional steering systems, in which a steering handle, for example in the form of a steering wheel, is mechanically fixedly connected to a steering gear via a steering column. Furthermore, vehicles are known with steer-by-wire steering systems, in which a direct mechanical connection between the steering handle and the steered wheels is dispensed with and the steering settings are transmitted exclusively electrically. To vary the wheel steering angles of the wheels, steer-by-wire steering systems comprise a wheel steering angle regulator configured as a central regulator or comprise a number of wheel steering angle regulators configured as individual wheel regulators. A disadvantage of individual wheel regulators over central regulators is that these individual wheel regulators have a relatively high overall energy demand or energy usage. For example, unlike a central regulator, the individual wheel regulators must provide actuator forces to maintain the desired target position both when external forces act symmetrically, i.e., when driving straight ahead, and also when they act asymmetrically, i.e., when driving around a curve. This necessarily leads to an increase in the power consumption of the individual wheel steering regulators. Summary of the Invention [Problem to be solved by the invention]
[0003] Starting from the above, the object of the present invention is to provide a method and a vehicle having improved properties, in particular with regard to efficiency. This object is achieved by the features of claims 1, 14 and 15, whereas reference can be made to the dependent claims for advantageous embodiments and developments of the invention. [Means for solving the problem]
[0004] Disclosure of the Invention A method, in particular a computer-implemented method, for reducing the energy demand and / or energy usage of a vehicle is proposed, the vehicle comprising a steering system with at least two wheel steering angle adjusters for changing the wheel steering angles of the respective wheels individually and a vehicle sensor for identifying a driving situation, in which in at least one operating state, in particular an operating state different from an error operating state, in which a predefined driving situation is identified by the vehicle sensor, preferably from a group of predefined driving situations, a power consumption of the at least one wheel steering angle adjuster is reduced, in particular intentionally, in order to reduce the energy demand and / or energy usage. In particular, in this case the at least one wheel steering angle adjuster is driven such that the power consumption of the at least one wheel steering angle adjuster is reduced below the power consumption of the at least one wheel steering angle adjuster assumed for the driving situation. The wheel steering angle adjusters are in this case in particular configured as individual wheel adjusters. Basically, in an operating state for which a corresponding predetermined driving situation is determined by the vehicle sensor or in at least one further operating state, the power consumption of a plurality of wheel steering angle control devices, for example at least two, at least three and / or at least four wheel steering angle control devices, can also be particularly deliberately reduced in order to reduce the energy demand and / or energy usage. Such an embodiment can improve the efficiency, in particular the energy efficiency, the module efficiency, the power efficiency and / or the cost efficiency. Furthermore, the power consumption of the wheel steering angle control devices can be dynamically adapted depending on the driving situation. Furthermore, the life and / or fatigue strength of the vehicle can advantageously be improved.
[0005] Preferably, the vehicle is configured as a motor vehicle and includes, in particular, a steering system and vehicle sensors, in particular arranged for determining at least one current and / or future driving situation. For this purpose, the vehicle sensors may, for example, include at least one sensor element, in particular electrical, magnetic and / or optical, a navigation system, for example with a GPS module, and / or a communication module for wireless communication with an external computer network, for example with a cloud network. Furthermore, the steering system is configured as a steer-by-wire steering system, in which the steering settings are preferably transmitted to the wheels purely electrically. The steering system in this specification includes a wheel steering angle adjustment device for changing the respective wheel steering angle individually for the wheels, and an operating unit, which is preferably mechanically separated from the wheel steering angle adjustment device. By "operating unit" is to be understood an input unit, in particular operable by the driver, for driving the wheel steering angle adjustment device. The operating unit may in particular include a steering wheel, for example in the form of a steering wheel, and a feedback actuator, for example in the form of an electric motor, for generating a steering resistance and / or a return torque on the steering wheel, preferably. A "wheel steering angle adjustment device" is to be understood as an actuator unit, in particular operatively connected to the wheels, which is provided for transmitting a steering setting to the wheels by varying the wheel steering angle of the wheels and thereby advantageously at least for controlling the orientation of the wheels and / or for influencing the driving direction of the vehicle. For this purpose, the wheel steering angle adjustment device preferably comprises at least one steering adjustment element, for example in the form of a rack, and at least one steering actuator, for example in the form of an electric motor, operatively connected to the steering adjustment element. In this case, at least two wheel steering angle adjustment devices can be associated with an axle configured as the front axle of the vehicle or with a further axle configured as the rear axle. In principle, the vehicle can also comprise more than two wheel steering angle adjustment devices, for example four wheel steering angle adjustment devices configured as individual wheel adjustment devices, in which case two wheel steering angle adjustment devices are assigned to each axle.
[0006] Furthermore, the vehicle comprises a computing unit arranged to carry out the method for reducing the energy demand and / or energy usage of the vehicle. A "computing unit" is to be understood as an electrical and / or electronic unit having, in particular, an information input, an information processing and an information output. Advantageously, the computing unit further comprises at least one processor, at least one operating memory, at least one input means and / or output means, at least one operating program, at least one control routine, at least one calculation routine, at least one identification routine, at least one evaluation routine and / or at least one drive routine. In particular, the computing unit is arranged to drive at least one wheel steering angle adjustment device, preferably all wheel steering angle adjustment devices. In this context, the computing unit is arranged at least for reducing the power consumption of at least one wheel steering angle adjustment device in order to reduce the energy demand and / or energy usage, in particular for reducing the power consumption of at least one wheel steering angle adjustment device below the power consumption of said at least one wheel steering angle adjustment device envisaged for the driving situation. Furthermore, the calculation unit may be provided for interacting with the vehicle sensors to determine, in particular, a current and / or future driving situation and to compare it with at least one predefined driving situation. The one and / or a plurality of predefined driving situations can be stored, for example, in an operating memory. Furthermore, the calculation unit in this context may be provided for determining and evaluating, in particular, a future and / or future vehicle trajectory of the vehicle. Preferably, the calculation unit is in this case integrated in a control device of the vehicle, for example in a central vehicle control device or in a control device of the steering system, in particular in the form of a steering control device. "Provided" is to be understood in particular as being specially programmed, designed and / or installed. An object being provided for a predefined function is to be understood in particular as being that the object fulfills and / or executes this predefined function at least in a use state and / or in an operating state.
[0007] The power consumption of the at least one wheel steering angle adjustment device can be reduced in the operating state, for example by at least 10%, at least 50% or at least 80%, so that at least one minimum steering function of the wheel steering angle adjustment device is maintained. However, it is preferably proposed to omit active driving of the at least one wheel steering angle adjustment device in the operating state and / or to at least temporarily deactivate the at least one wheel steering angle adjustment device, so that a particularly high efficiency can be achieved. In this connection, the motor torque of the at least one wheel steering angle adjustment device, in particular the steering actuator, can be set to zero. Alternatively or additionally, the at least one wheel steering angle adjustment device can be transferred, for example, to a waiting mode and / or a standby mode. In that case, it can be achieved that the non-driven or non-activated wheel steering angle adjustment device is "coupled" by utilizing the vehicle body kinematics, in particular in the form of following.
[0008] Furthermore, it is proposed to monitor at least one environmental quantity and / or at least one operating quantity of the vehicle in the operating state and evaluate it in order to determine a restart condition. Preferably, in this case, the environmental quantity and / or operating quantity to be monitored and / or evaluated in particular are selected and / or changed depending on the current driving situation. In that case, preferably, a restart condition is used to restart the normal operation of the at least one wheel steering angle control device. As environmental quantity, for example, camera data and / or roadway map data can be used, while as operating quantity, for example, actuation of the vehicle pedal of the vehicle, actuation of the parking brake of the vehicle, detection signals of inertial sensors of the vehicle, vehicle speed, steering wheel displacement, wheel steering angle, rack position of the wheel steering angle control device and / or wheel speed signals can be used. Furthermore, the determination of the environmental quantity and / or operating quantity can be performed using vehicle sensors of the vehicle and / or in particular additional sensors. As a result, a particularly high operational reliability can be achieved and advantageously a predictive restart of the at least one wheel steering angle control device can be achieved.
[0009] Particularly preferably, it is further proposed to temporarily limit the rate of increase of the motor torque when restarting the normal operation of the at least one wheel steering angle adjuster, in particular the position control device used to drive the at least one wheel steering angle adjuster, in particular until the target position is reached. However, as an alternative, a gain scheduling approach can also be used when restarting the normal operation of the at least one wheel steering angle adjuster, in order to prevent any irritation to the driver, in particular when restarting the normal operation of the at least one wheel steering angle adjuster.
[0010] Furthermore, it is proposed to adapt, in the operating state, the in particular virtual steering ratio between the steering wheel and the wheel steering angle adjustment device of the steering system in such a way that the steering or driving behavior remains unchanged, thereby providing a function that is advantageously unnoticeable in particular for the driver.Steering ratio in this context defines the correlation in particular between the steering setting at the steering wheel and the wheel steering angle of one or more wheels.
[0011] Furthermore, it is proposed to take into account at least one further environmental variable and / or at least one further operating variable of the vehicle when reducing the power consumption of the at least one wheel steering angle control device. Preferably, in this case, the further environmental variable and / or the further operating variable are selected and / or changed depending on the respective driving situation. As the further environmental variable, for example, camera data and / or road map data can be used, while as the operating variable, for example, the operation of the vehicle pedal of the vehicle, the operation of the parking brake of the vehicle, the detection signal of an inertial sensor of the vehicle, the vehicle speed, the displacement of the steering wheel, the wheel steering angle, the rack position of the wheel steering angle control device and / or the wheel rotation speed signal can be used. Basically, the further environmental variable can be identical to the environmental variable and / or the further operating variable can be identical to the operating variable.
[0012] According to a further embodiment, it is proposed to take into account the extent of the upcoming journey when reducing the power consumption of the at least one wheel steering angle adjustment device, which in particular further improves efficiency and makes it possible to dispense with continuous switching of the at least one wheel steering angle adjustment device.Furthermore, when reactivating the normal operation of the at least one wheel steering angle adjustment device, the extent of the upcoming journey can also be taken into account, so that a particularly predictive reactivation can be achieved.
[0013] It is further proposed that the direction of the curve is taken into account when reducing the power consumption of the at least one wheel steering angle control device. In this connection, it is conceivable, for example, to reduce the power consumption only in the wheel steering angle control device on the inside of the curve or in the wheel steering angle control device on the outside of the curve. Furthermore, the direction of the curve can also be taken into account when reactivating the normal operation of the at least one wheel steering angle control device. This makes it possible, inter alia, to achieve a particularly high degree of flexibility and / or variability.
[0014] It is preferably further proposed to take into account the vehicle speed and / or the lateral acceleration of the vehicle when reducing the power consumption of the at least one wheel steering angle control device. In this connection, the reduction of the power consumption of the at least one wheel steering angle control device can be carried out, for example, only below or above a predefined limit vehicle speed and / or limit lateral acceleration. Furthermore, the vehicle speed and / or the lateral acceleration of the vehicle can also be taken into account when reactivating the normal operation of the at least one wheel steering angle control device. By taking into account the vehicle speed and / or the lateral acceleration of the vehicle, safety-critical driving situations can advantageously be identified, so that in such cases a reduction of the power consumption of the at least one wheel steering angle control device can be omitted or an earlier reactivation of the normal operation can be achieved.
[0015] It is further proposed that the health and / or wear state of the at least one wheel steering angle control device is taken into account when reducing the power consumption of the at least one wheel steering angle control device. In this connection, it is conceivable, for example, to reduce the power consumption only in wheel steering angle control devices that have a poor or relatively poor health and / or wear state. This makes it possible, in particular, to increase the service life and / or fatigue strength of the vehicle.
[0016] In particular, when the power consumption of the at least one wheel steering angle control device is reduced, a particularly high energy efficiency can be achieved if the current power demand of the at least one wheel steering angle control device and / or the power demand required by the driving situation is taken into account. In this connection, it is conceivable, for example, to reduce the power consumption only in wheel steering angle control devices that have a high or relatively high power demand.
[0017] It is further proposed to take into account the loading state of the vehicle when reducing the power consumption of at least one wheel steering angle control device. The loading state of the vehicle is directly linked to the power demand of the wheel steering angle control device, so that a high loading state, for example, leads to an increased power demand of the wheel steering angle control device, and an asymmetric loading state leads to different power demands of the wheel steering angle control devices. By taking the loading state into account, therefore, advantageously, wheel steering angle control devices with a high or relatively high power demand can be identified and, if necessary, their power consumption can be reduced accordingly, which can further improve the energy efficiency.
[0018] According to an embodiment, the first predetermined driving situation corresponds to a driving process with low steering demands, for example a driving with low vehicle speed and low lateral acceleration or a large curve radius, and in order to reduce the energy demand and / or energy usage, it is proposed to reduce the power consumption of the wheel steering angle control devices, in particular the power consumption of one wheel steering angle control device of the two wheel steering angle control devices and / or exactly one wheel steering angle control device. In particular, in this embodiment, the power consumption of only some wheel steering angle control devices of the plurality of wheel steering angle control devices is reduced. In this connection, the wheel steering angle control devices whose power consumption is reduced can be, for example, a wheel steering angle control device on the inside of a curve, a wheel steering angle control device on the outside of a curve, a wheel steering angle control device having a poor health and / or wear state, and / or a wheel steering angle control device having a relatively high power demand. Furthermore, while the wheel steering angle control device with reduced power consumption is maintaining a straight-ahead position by utilizing the vehicle body kinematics or cooperating according to the yawing movement of the vehicle, the remaining wheel steering angle control device can generate a yawing movement of the vehicle, which can reduce the energy demand and / or energy usage and advantageously increase the efficiency, especially in driving processes with low, i.e. non-zero, steering demands.
[0019] According to a further embodiment, the second predefined driving situation corresponds to a stopping process in which the vehicle is stationary, and in order to reduce the energy demand and / or energy usage, it is proposed to reduce the power consumption of the two, preferably all, wheel steering angle control devices, so that the energy demand and / or energy usage can be reduced and advantageously the efficiency can be increased, in particular during stopping processes in which the vehicle is stationary.
[0020] Furthermore, if the third predetermined driving situation corresponds to straight driving, i.e. corresponds to a driving process with a steering request equal to or approximately equal to zero and preferably an increased vehicle speed, it is proposed to reduce the power consumption of the two wheel steering angle adjustment devices, preferably of all wheel steering angle adjustment devices, in order to reduce the energy demand and / or energy usage. In this connection, it is also possible in this case to utilize the body kinematics, in particular in the form of following, where the return behavior of the axle due to following is speed-dependent and the wheels are centered better and better as the vehicle speed increases. This allows the energy demand and / or energy usage to be reduced, particularly when driving straight, and advantageously increases the efficiency.
[0021] The method and vehicle for reducing the energy demand and / or energy usage of a vehicle should not be limited to the applications and embodiments described above, and in particular, the method and vehicle for reducing the energy demand and / or energy usage of a vehicle may have a different number of individual elements, components and units than those described herein to fulfill the functions described herein.
[0022] drawing Further advantages will become apparent from the following description of the drawings, in which an embodiment of the invention is shown. [Brief description of the drawings]
[0023] [Figure 1a] FIG. 1 is a schematic diagram of a vehicle with a steering system configured as a steer-by-wire steering system. [Figure 1b] FIG. 1 is a schematic diagram of a vehicle with a steering system configured as a steer-by-wire steering system. [Diagram 2] 2 is an exemplary flow chart with main method steps of a method for reducing the energy demand and / or energy usage of a vehicle. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] Description of the embodiment 1a and 1b show schematic diagrams of a vehicle 10, exemplarily configured as a passenger car, with a number of wheels 18, 20 and a steering system 12. The steering system 12 has an operative connection with the wheels 18, 20 and is provided for influencing the direction of travel of the vehicle 10. Furthermore, the steering system 12 is configured as a steer-by-wire steering system, in which the steering setting in at least one operating state is electrically transmitted to the wheels 18, 20.
[0025] The steering system 12 comprises an operating unit 28 known per se. The operating unit 28 comprises a steering wheel 24, for example in the form of a steering wheel, which can in particular be operated by the driver, and a feedback actuator 30, which is in particular mechanically coupled to the steering wheel 24. In the present embodiment, the feedback actuator 30 is provided for generating at least a steering resistance and / or a return torque for the steering wheel 24. Alternatively, the steering wheel can also be configured as a joystick, a steering lever and / or a steering ball or the like. Furthermore, it is basically also possible to omit the feedback actuator. Furthermore, it is also conceivable to omit the operating unit altogether.
[0026] Furthermore, the steering system 12 comprises a number of wheel steering angle adjusters 14, 16. In the present embodiment, the steering system 12 comprises, for example, two wheel steering angle adjusters 14, 16, which are configured as individual wheel steering angle adjusters and are arranged on one axle configured as the front axle, in particular the wheel steering angle adjuster 14 and the further wheel steering angle adjuster 16, and thus in particular a wheel-individual steering section. The wheel steering angle adjusters 14, 16 are at least substantially identically configured. The wheel steering angle adjusters 14, 16 are configured separately from one another and have no mechanical connection in the present embodiment. The wheel steering angle adjusters 14, 16 can be driven independently of one another. Furthermore, the wheel steering angle adjusters 14, 16 are connected purely electrically to the operating unit 28 and thus to the steering wheel 24. Each of the wheel steering angle adjustment devices 14, 16 has an operative connection with exactly one of the wheels 18, 20, in this embodiment exemplarily the front wheel. The wheel steering angle adjustment devices 14, 16 are provided for varying the respective wheel steering angle of the corresponding wheels 18, 20 depending on the steering setting. For this purpose, each of the wheel steering angle adjustment devices 14, 16 includes a steering adjustment element 32, 34 exemplarily configured as a rack and a steering actuator 36, 38 which interacts with the steering adjustment element 32, 34 and is configured as an electric motor. In principle, it is of course also possible for the steering system to include at least one wheel steering angle adjustment device configured as a central adjustment device. Furthermore, the steering system can also include at least four wheel steering angle adjustment devices configured as individual wheel adjustment devices. In principle, the steering system can also include a combination of wheel steering angle adjustment devices configured as individual wheel adjustment devices and wheel steering angle adjustment devices configured as a central adjustment device. Furthermore, it is possible in particular to assign at least one wheel steering angle adjustment device to a wheel configured as a rear wheel.
[0027] Furthermore, the vehicle 10 comprises a vehicle sensor 22 known per se for identifying a driving situation. The vehicle sensor 22 is provided in particular for determining at least one current and / or future driving situation and for providing a sensor signal correlating to the driving situation. In the present embodiment, the vehicle sensor 22 is provided in this case at least for determining at least one environmental quantity and / or at least one operating quantity of the vehicle 10. As environmental quantities, for example camera data and / or roadway map data can be determined, while as operating quantities, for example actuation of the vehicle pedal of the vehicle 10, actuation of the parking brake of the vehicle 10, detection signals of inertial sensors of the vehicle 10, the vehicle speed, the displacement of the steering wheel 24, the wheel steering angle, the rack position of the wheel steering angle adjusters 14, 16 and / or wheel rotation speed signals can be determined. For this purpose, the vehicle sensor 22 may comprise at least one sensor element (not shown), in particular electrical, magnetic and / or optical. Alternatively or additionally, the vehicle sensor 22 may comprise a navigation system (not shown), for example with a GPS module. Furthermore, the vehicle sensor 22 may include a communication module (not shown) for wireless communication with an external computer network, e.g., a cloud network, by means of which roadway map data can be retrieved, etc. In principle, however, it is also conceivable to completely omit the sensor elements, the navigation system and / or the communication module.
[0028] Furthermore, the vehicle 10 comprises a control device 40, which in this embodiment is configured as a steering control device and is therefore part of the steering system 12. The control device 40 has an electrical connection with the operating unit 28. Furthermore, the control device 40 has an electrical connection with the wheel steering angle adjustment devices 14, 16. Furthermore, the control device 40 has an electrical connection with the vehicle sensors 22. The control device 40 is provided for controlling at least the operation of the steering system 12.
[0029] The control device 40 comprises a calculation unit 26. The calculation unit 26 comprises at least one processor (not shown), for example in the form of a microprocessor, and at least one operating memory (not shown). Furthermore, the calculation unit 26 comprises at least one operating program stored in the operating memory, the operating program comprising at least one calculation routine, at least one identification routine, at least one evaluation routine and / or at least one drive routine. In principle, the control device can also be different from the steering control device and can be configured, for example, as an individual central vehicle control device with a central calculation unit. Furthermore, it is also conceivable to provide separate control devices for the respective wheel steering angle adjustment devices and the operating unit, which are communicatively connected to each other.
[0030] A disadvantage of individual wheel adjusters compared to a central adjuster is that they have a relatively high overall energy demand or energy usage, for example, unlike a central adjuster, the individual wheel adjusters must provide actuator forces to maintain the desired target position both when external forces act symmetrically and when they act asymmetrically.
[0031] Therefore, in the following, a method is proposed for reducing the energy demand and / or energy usage of the vehicle 10 in order to improve the efficiency. In the present embodiment, the method is exemplarily described in connection with the wheels 18, 20 and the wheel steering angle adjustment devices 14, 16 associated with the wheels 18, 20, but the following description is also applicable to further wheels, in particular wheels on a further axle configured as a rear axle, and corresponding further wheel steering angle adjustment devices. In the present embodiment, in particular a calculation unit 26 is provided for carrying out the method and for this purpose has a computer program with in particular corresponding program code means.
[0032] According to the invention, in at least one operating state, in which a certain driving situation is determined by the vehicle sensor 22, the power consumption of the at least one wheel steering angle adjustment device 14, 16 is reduced in order to reduce the energy demand and / or energy usage. In this case, the at least one wheel steering angle adjustment device 14, 16 is driven such that the power consumption of the at least one wheel steering angle adjustment device 14, 16 is reduced below the power consumption of the at least one wheel steering angle adjustment device 14, 16 assumed for the driving situation. In the present embodiment, for this purpose, in the operating state, active driving of the at least one wheel steering angle adjustment device 14, 16 is omitted and the motor torque of the at least one wheel steering angle adjustment device 14, 16, in particular of the corresponding steering actuator 36, 38, is set to zero. However, as an alternative, the at least one wheel steering angle adjustment device can also be at least temporarily deactivated, for example put into a waiting and / or standby mode. Furthermore, it is conceivable to reduce the power consumption of the at least one wheel steering angle adjuster only in such a way that a minimum steering function of the at least one wheel steering angle adjuster is maintained.
[0033] Furthermore, in the operating state, at least one environmental variable and / or at least one operating variable of the vehicle 10 are monitored and evaluated in order to identify a restart condition, which is used to restart the normal operation of the at least one wheel steering angle controller 14, 16. In this connection, the environmental variables and / or operating variables to be specifically monitored and / or evaluated can also be selected and / or changed depending on the current driving situation. As environmental variables, for example, camera data and / or road map data can be used, while as operating variables, for example, the operation of the vehicle pedal, the operation of the parking brake, the detection signals of the inertial sensors, the vehicle speed, the displacement of the steering wheel 24, the wheel steering angle, the rack position of the wheel steering angle controller 14, 16 and / or the wheel rotation speed signals can be monitored.
[0034] Furthermore, in this embodiment, when resuming normal operation of the at least one wheel steering angle adjuster 14, 16, in particular the position control device used to drive the at least one wheel steering angle adjuster 14, 16, the rate of increase of the motor torque is temporarily limited, in this embodiment, in particular until the target position is reached, thereby preventing driver irritation when normal operation is resumed. However, alternatively, a gain scheduling approach can also be used when resuming normal operation of the at least one wheel steering angle adjuster.
[0035] Furthermore, when reducing the power consumption of the at least one wheel steering angle adjuster 14, 16, at least one further environmental variable and / or at least one further operating variable of the vehicle 10, the length of the upcoming journey, the direction of the curve, the vehicle speed, the lateral acceleration of the vehicle 10, the health and / or wear state of the at least one wheel steering angle adjuster 14, 16, the current power demand of the at least one wheel steering angle adjuster 14, 16 and / or the power demand required for the driving situation, and / or the loading state of the vehicle 10 can be taken into account. When reactivating the normal operation of the at least one wheel steering angle adjuster 14, 16, the length of the upcoming journey, the direction of the curve, the vehicle speed and / or the lateral acceleration of the vehicle 10 can likewise be taken into account to achieve a particularly foreseen reactivation. Furthermore, a particularly efficient deactivation and / or reactivation of the at least one wheel steering angle adjuster 14, 16 can be achieved, especially when the driving maneuver is automated.
[0036] In the following, exemplary driving situations are described in which the method generally described above can be advantageously applied.
[0037] In this description, the first predetermined driving situation may correspond to a driving process with low steering demands, for example a driving with low vehicle speed and low lateral acceleration or a large curve radius. In order to reduce the energy demand and / or energy usage, in this embodiment, the power consumption of the individual wheel steering angle adjusters 14, 16, i.e. of the wheel steering angle adjuster 14 or the further wheel steering angle adjuster 16, can be reduced. Furthermore, the wheel steering angle adjuster 14, 16 with reduced power consumption can generate a yawing movement of the vehicle 10 by the remaining wheel steering angle adjuster 14, 16 while the wheel steering angle adjuster 14, 16 with reduced power consumption holds a straight-ahead position, advantageously by utilizing the vehicle body kinematics, or cooperates according to the yawing movement of the vehicle 10. However, in this embodiment, it is also possible to alternatively reduce the power consumption of the two wheel steering angle adjusters and generate a yawing movement of the vehicle by using the brake system and / or the ESP system. Furthermore, due to a slight phase shift between the reduced-power wheel steering angle adjuster 14,16 and the residual wheel steering angle adjuster 14,16, the residual wheel steering angle adjuster 14,16 or the path-following wheels 18,20 coupled to the residual wheel steering angle adjuster 14,16 tend to be steered slightly more strongly when entering a curve in order to maintain the unchanged agility of the vehicle 10. In this case, in order to improve the inconspicuousness of the function, the especially virtual steering ratio between the steering wheel 24 and the wheel steering angle adjuster 14,16 can be adapted so that the steering or driving behavior remains unchanged. Furthermore, by monitoring environmental and / or operating quantities of the vehicle 10, such as, for example, camera data and / or detection signals of inertial sensors, an intervention can be made if necessary, for example in the case of critical driving situations with relatively large driving dynamics, and possibly the normal operation of the reduced-power wheel steering angle adjuster 14,16 can be reactivated.
[0038] In this connection, the wheel steering angle control device 14, 16 with reduced power consumption may be, for example, a wheel steering angle control device on the inside of a curve or, alternatively, a wheel steering angle control device on the outside of a curve. Furthermore, the wheel steering angle control device 14, 16 with reduced power consumption may be a wheel steering angle control device with a relatively poor health and / or wear state, which can advantageously increase the life and / or fatigue strength of the vehicle 10. In this case, for example, learning algorithms in the form of artificial intelligence, particularly preferably recurrent neural networks, can be used to determine the health and / or wear state of the at least one wheel steering angle control device 14, 16. Furthermore, the wheel steering angle control device 14, 16 with reduced power consumption may be a wheel steering angle control device with a relatively high power demand. In this connection, it must be taken into account that the loading state of the vehicle 10 is directly linked to the power demand of the wheel steering angle control devices 14, 16, so that, for example, an asymmetric loading state may result in different power demands of the wheel steering angle control devices 14, 16. The same basically applies to asymmetries of the vehicle body.
[0039] The second predefined driving situation may correspond to a stopping process, in which the vehicle 10 is stationary. In order to reduce the energy demand and / or energy usage, in this embodiment the power consumption of the two wheel steering angle control devices 14, 16, i.e. the wheel steering angle control device 14 and the further wheel steering angle control device 16, can be reduced. However, in this embodiment it is also possible to reduce the power consumption of a single wheel steering angle control device instead. To identify a stopping process, for example, the operation of the vehicle pedals, in particular the brake pedal, the wheel speed signal, the operation of the parking brake, the signal of the start-stop system and / or a red light detected by a camera can be identified. However, if the roadway is very slippery, there is a risk that the wheels 18, 20 will rotate spontaneously even in the stationary state, so that in this case it is important to monitor the state of the vehicle 10, for example the wheel speed signal and, if necessary, to reactivate the normal operation of the wheel steering angle control devices 14, 16. Additionally, the above information can also be used to determine the friction value of the roadway or the ground.
[0040] The third predefined driving situation may correspond to straight driving, i.e. a driving process with a steering request equal to zero. In order to reduce the energy demand and / or energy use, in this embodiment the power consumption of the two wheel steering angle adjusters 14, 16, i.e. the wheel steering angle adjuster 14 and the further wheel steering angle adjuster 16, can be reduced. However, in this embodiment it is also possible to reduce the power consumption of a single wheel steering angle adjuster instead. In this case too, vehicle body kinematics can be utilized, in particular in the form of following, where the return behavior of the axle due to following is speed-dependent, and the wheels 18, 20 are centered better and better as the vehicle speed increases. In this connection, depending on the design of the vehicle 10, the geometry of the wheel suspension of the vehicle 10 can also be adapted to enhance effects such as self-centering. In this embodiment too, by monitoring the environmental and / or operating quantities of the vehicle 10, interventions can be made if necessary and, if necessary, the normal operation of the wheel steering angle adjusters 14, 16 can be reactivated.
[0041] Finally, FIG. 2 shows an exemplary flow chart with the main method steps of a method for reducing the energy demand and / or energy usage of a vehicle 10.
[0042] In method step 50, first of all, a current and / or future driving situation is determined and evaluated by the vehicle sensors 22 in interaction with the calculation unit 26. In this connection, once a predefined driving situation has been identified, in particular from a group of predefined driving situations, method step 52 is proceeded to.
[0043] In order to reduce the energy demand and / or the energy usage, the power consumption of the at least one wheel steering angle adjuster 14, 16 is reduced in method step 52, in particular to be reduced below the power consumption of the at least one wheel steering angle adjuster 14, 16 expected for the driving situation. In this case, active activation of the at least one wheel steering angle adjuster 14, 16 is omitted and / or the at least one wheel steering angle adjuster 14, 16 is at least temporarily deactivated.
[0044] Then, in method step 54, at least one environmental variable and / or at least one operating variable of the vehicle 10 are monitored and evaluated. As environmental variables, for example, camera data and / or roadway map data can be used, while as operating variables, for example, the operation of the vehicle pedal, the operation of the parking brake, the detection signals of the inertial sensors, the vehicle speed, the displacement of the steering wheel 24, the wheel steering angle, the rack position of the wheel steering angle adjusters 14, 16 and / or the wheel speed signals can be monitored. In this context, the environmental variables and / or operating variables to be monitored and / or evaluated in particular are selected and / or changed depending on the current driving situation. If a restart condition is identified when monitoring the environmental variables and / or operating variables, method step 56 is proceeded to.
[0045] In method step 56, depending on the restart condition, normal operation of the at least one wheel steering angle controller 14, 16 is restarted. For this purpose, the reduction in the power consumption of the at least one wheel steering angle controller 14, 16 is terminated and the at least one wheel steering angle controller 14, 16 is actively driven again.
[0046] The exemplary flow chart of Fig. 2 is merely an exemplary illustration of a method for reducing the energy demand and / or energy usage of the vehicle 10. In particular, it is also possible to modify individual method steps or to add additional method steps. In this connection, it is conceivable, for example, to adapt the steering ratio between the steering wheel 24 and the wheel steering angle adjusters 14, 16 in such a way that the steering or driving behavior in a given driving situation remains unchanged. Furthermore, for example, the rate of increase of the motor torque can be temporarily limited when reactivating the normal operation of at least one wheel steering angle adjuster 14, 16.
Claims
1. A method for reducing the energy demand and / or energy consumption of a vehicle (10), particularly an automobile, The vehicle (10) includes a steering system (12) equipped with at least two wheel steering angle adjustment devices (14, 16) for individually changing the steering angle of each wheel (18, 20), and a vehicle sensor (22) for identifying driving conditions. A method to reduce the power consumption of at least one of the wheel steering angle adjustment devices (14, 16) in order to reduce the energy demand and / or energy consumption in at least one operating state in which a predetermined driving condition is identified by the vehicle sensor (22), wherein the power consumption of the at least one wheel steering angle adjustment device (14, 16) is reduced to a level below the power consumption of the at least one wheel steering angle adjustment device (14, 16) assumed for the driving condition.
2. In the aforementioned operating state, the active driving of the at least one wheel steering angle adjustment device (14, 16) is omitted, and / or the at least one wheel steering angle adjustment device (14, 16) is deactivated at least temporarily. The method according to claim 1.
3. In the aforementioned operating state, at least one environmental quantity and / or at least one operational quantity of the vehicle (10) are monitored and evaluated in order to identify restart conditions. The restart condition is used to restart the normal operation of at least one wheel steering angle adjustment device (14, 16). The method according to claim 1.
4. In the aforementioned operating state, the steering ratio between the steering handle (24) of the steering system (12) and the wheel steering angle adjustment devices (14, 16) is adjusted so that the steering behavior remains constant. The method according to claim 1.
5. When reducing the power consumption of the at least one wheel steering angle adjustment device (14, 16), at least one further environmental quantity and / or at least one further operating quantity of the vehicle (10) are taken into consideration. The method according to claim 1.
6. When reducing the power consumption of the at least one wheel steering angle adjustment device (14, 16), the extent of the remaining travel section and / or the direction of the curve are taken into consideration. The method according to claim 1.
7. When reducing the power consumption of the at least one wheel steering angle adjustment device (14, 16), the vehicle speed and / or lateral acceleration of the vehicle (10) are taken into consideration. The method according to claim 1.
8. When reducing the power consumption of the at least one wheel steering angle adjustment device (14, 16), the health and / or wear condition of the at least one wheel steering angle adjustment device (14, 16) is taken into consideration. The method according to claim 1.
9. When reducing the power consumption of the at least one wheel steering angle adjustment device (14, 16), the current power demand of the at least one wheel steering angle adjustment device (14, 16) and / or the power demand required for the driving conditions are taken into consideration. The method according to claim 1.
10. When reducing the power consumption of the at least one wheel steering angle adjustment device (14, 16), the load condition of the vehicle (10) is taken into consideration. The method according to claim 1.
11. The first predetermined driving condition corresponds to a driving process with low steering requirements, In order to reduce the aforementioned energy demand and / or energy consumption, the power consumption of one wheel steering angle adjustment device (14, 16) is reduced. The method according to claim 1.
12. The second predetermined driving condition corresponds to the stopping process in which the vehicle (10) is in a stationary state. In order to reduce the aforementioned energy demand and / or energy consumption, the power consumption of the two wheel steering angle adjustment devices (14, 16) is reduced. The method according to claim 1.
13. The third specified driving condition corresponds to driving in a straight line. In order to reduce the aforementioned energy demand and / or energy consumption, the power consumption of the two wheel steering angle adjustment devices (14, 16) is reduced. The method according to claim 1.
14. A computing unit (26) for carrying out the method according to any one of claims 1 to 13.
15. Vehicles (10), especially automobiles, Multiple wheels (18, 20) and A steering system (12) including at least two wheel steering angle adjustment devices (14, 16) for individually changing the steering angle of each of the plurality of wheels (18, 20), A vehicle sensor (22) for identifying driving conditions, The calculation unit (26) according to claim 14, A vehicle (10) equipped with the following.