Method for operating a driver assistance system for a motor vehicle, driver assistance system and motor vehicle with a driver assistance system

Abstract

Method for operating a driver assistance system (10) for a motor vehicle (26), comprising the steps - Detecting the current airflow situation of the motor vehicle (26), - Determining an actual vehicle state resulting from the current flow situation, wherein the actual vehicle state includes an actual noise level (G) in an interior of the motor vehicle (26), - Generating a recommendation (24) for a driving maneuver to approximate the actual vehicle state to a target vehicle state, wherein the target vehicle state has a target noise level (G S ) in the interior of the motor vehicle (26).

Description

[0001] The present invention relates to a method for operating a driver assistance system for a motor vehicle. A recommendation for a driving maneuver is to be generated based on a detected current airflow situation of the motor vehicle and a resulting state of the motor vehicle. The invention further relates to a driver assistance system and a motor vehicle with such a driver assistance system.

[0002] The operation of a motor vehicle is influenced by, among other things, the phenomena of aerodynamics, particularly the occurrence of air resistance forces acting on the vehicle during operation, and aeroacoustics, i.e., the occurrence of wind noise in the vehicle interior. This is especially true for a motor vehicle that is at least partially electrically powered. Here, aerodynamics is a determining factor for a vehicle's range. Furthermore, the elimination of combustion engine noise makes wind noise a significant, if not the dominant, acoustic comfort factor in the vehicle interior.

[0003] Therefore, efforts are being made to design a vehicle shape and / or the shape of add-on components, such as exterior mirrors, in such a way that the drag coefficient (Cd) and the introduction of wind noise into the vehicle interior are as low as possible. The development of the shape is essentially based on idealized assumptions. In particular, it is assumed that a headwind hits the vehicle homogeneously from the front. Furthermore, the vehicle is usually viewed independently of its respective surroundings. However, it has been shown that under real-world conditions, a multitude of other factors play a role in the aerodynamic and / or aeroacoustic situation of a vehicle.These include, among other things, crosswinds and / or gusts of wind, buildings along the edges, for example, of a road, the topography of the vehicle's surroundings, vehicles traveling ahead (keyword: slipstreaming), and vehicles in adjacent lanes that can absorb crosswinds. The totality of these and other factors, which are summarized in the context of the present invention as the airflow situation, influences the actual air resistance for the vehicle as well as the wind noise actually carried into the vehicle interior.

[0004] The influence of slipstreaming on the actual aerodynamic drag of a motor vehicle has long been known. The aerodynamic advantage that can be achieved through slipstreaming depends, among other things, on the type and size of the vehicle ahead, as well as the distance maintained from that vehicle. An optimization method for this purpose is known, for example, from DE 10 2011 089 264 A1. This and other optimization methods are intended to help minimize aerodynamic drag for a motor vehicle when slipstreaming.

[0005] As described above, a given airflow situation not only results in a specific aerodynamic drag for a vehicle, but the airflow situation can also influence the ingress of wind noise into the vehicle's interior. This is disadvantageously not taken into account in existing optimization methods.

[0006] It is the object of the present invention to increase driving comfort for a motor vehicle occupant, particularly when driving in the slipstream.

[0007] The problem is solved by the subject matter of the independent patent claims. Further possible embodiments of the invention are disclosed in the subclaims, the description, and the figures.

[0008] The invention is based on the finding that a noise level in the motor vehicle interior caused by wind noise is influenced by a current airflow situation of the motor vehicle and that the airflow situation can be changed by a driving maneuver of the motor vehicle in such a way that the noise level also changes and, in particular, is reduced.

[0009] The invention provides a method for operating a driver assistance system for a motor vehicle. First, a current airflow situation of the motor vehicle is recorded. As described above, the airflow situation results from the totality of the factors influencing the airflow towards or around the motor vehicle. These can be a wind strength and / or an air pressure and / or an existing crosswind and / or gusts of wind and / or a topography of the vehicle's surroundings, since this can also influence the airflow towards or around the motor vehicle. The factors influencing the airflow situation can alternatively or additionally include motor vehicles driving ahead and / or behind and / or motor vehicles in adjacent lanes.

[0010] The factors that influence the airflow situation can be recorded in a variety of ways. For example, pressure sensors can be provided in the motor vehicle, in particular within an outer shell of the motor vehicle, which can record a generally prevailing air pressure and / or a change in air pressure in the form of gusts of wind or similar. Camera sensors on the motor vehicle, for example, can be used to record the aforementioned peripheral buildings and / or topography. It is also conceivable to use information from known maps for this purpose. For example, a map of the vehicle's surroundings can be stored in a navigation unit of the motor vehicle, on which peripheral buildings and / or topography are entered.Motor vehicles driving ahead and / or following behind and / or motor vehicles in adjacent lanes can also be detected via the camera sensors and / or by means of car-to-car communication between the motor vehicle and the surrounding motor vehicles.

[0011] The factors mentioned can be integrated into an aerodynamic model for the motor vehicle, whereby the aerodynamic model can be designed to output the current airflow situation. Vehicle control parameters, such as the current speed and / or the currently set accelerator pedal angle, can also be included in the aerodynamic model. The body shape of the motor vehicle can also be taken into account in the aerodynamic model. The input of additional factors into the aerodynamic model is also conceivable. Additional factors that can be included in the aerodynamic model include, for example, the state of the windows (open / closed) and / or a sunroof or convertible top. The positions of active aerodynamic elements of the motor vehicle (e.g. spoilers, flaps, flaps, blow-out and / or suction devices).

[0012] According to the invention, an actual vehicle state resulting from the current flow situation is determined, wherein the actual vehicle state includes an actual noise level in the interior of the motor vehicle. In the context of the present invention, the interior of the motor vehicle is the area within which vehicle occupants are typically located.

[0013] The actual noise level in the interior resulting from the airflow situation can be determined, for example, using an acoustic model designed to isolate typical wind noise from other noises from a total noise in the interior of the motor vehicle, wherein the total noise or background noise can be detected, for example, using one or more noise sensors. This ensures that only the actual noise level in the interior of the motor vehicle that does not include extraneous noise, such as conversations between passengers or similar, is determined as resulting from the current airflow situation. In other words, only the actual noise level in the interior of the motor vehicle that is directly related to the current airflow situation of the motor vehicle is determined.

[0014] In the further course of the method according to the invention, the actual noise level is to be approximated to a target noise level in the interior of the motor vehicle. The target noise level can be adapted to the preference of a motor vehicle occupant. In contrast to known noise reduction methods, such as active noise cancellation (ANC), the invention provides for generating a recommendation for a driving maneuver to remedy the situation. If followed, the recommended driving maneuver will lead to a changed positioning of the motor vehicle in relation to its surroundings, i.e., in relation to surrounding vehicles and / or peripheral buildings. This changes the above-described airflow situation in such a way that the actual noise level in the interior of the motor vehicle resulting from the airflow situation approximates the target noise level.

[0015] The invention advantageously allows a noise level generated in an interior of a motor vehicle by a current airflow situation of the motor vehicle to be reduced without the need to implement complex measures, for example an active noise-cancelling system.

[0016] The invention also includes embodiments which provide additional advantages.

[0017] One embodiment provides that the actual vehicle state comprises an actual value for at least one additional parameter and the target vehicle state comprises a target value for the at least one additional parameter. When generating the recommendation, a balance is struck between reaching the target noise level and reaching the target value of the at least one additional parameter according to a weighting rule. The at least one additional parameter can be an air resistance and / or a range and / or a vehicle stability of the motor vehicle. In other words, when generating the recommendation for the driving maneuver, not only the approach of the actual noise level to the target noise level can be taken into account, but also the approach of the actual value of one or more of the aforementioned parameters to the corresponding target value.A weighting can be applied to determine which of the approximations should be preferred.

[0018] It may happen that a vehicle occupant considers a low noise level in the vehicle interior more important than, for example, increased range and / or reduced air resistance for the vehicle. This situation is based on the knowledge that, for example, when slipstreaming, the positions for minimum air resistance and minimum noise level do not necessarily coincide. In other words, the position of the lowest air resistance for the vehicle (the aerodynamic sweet spot) may be ten meters behind a vehicle in front, while the position of the lowest noise level in the vehicle interior (the aeroacoustic sweet spot) may be 20 or even 25 meters behind the vehicle in front. In this case, the aforementioned weighting can advantageously be used to generate a recommendation for a driving maneuver that can take the vehicle occupant's preference into account.

[0019] A further embodiment provides that the weighting rule is created based on user input from the vehicle occupant. The user input can be made, for example, by operating an input device on the motor vehicle at the start of a journey, when driving in, or even while driving. For this purpose, a mechanical or digital slider can be moved along a scale, for example. The end points of the scale can be the minimized air resistance on the one hand and the minimized noise level on the other. It can also be provided to enable user input on a graphical control panel or user interface, whereby the control panel can offer two, three or more parameters for selection. This allows the vehicle occupant to particularly conveniently weight the parameters according to their preferences.

[0020] Another embodiment provides for the recommendation to be visualized on a display device of the motor vehicle. In other words, the recommendation for the driving maneuver can be provided as a visual representation. The display device can be configured, for example, as a head-up display. Another possible embodiment of the display device is a (touch) display, for example, arranged in a center console of the motor vehicle.

[0021] The recommendation can be visualized as a selection of possible spatial positions of the vehicle relative to objects in its surroundings. The display on the aforementioned head-up display is particularly advantageous for this purpose. For example, a possible spatial position of the vehicle can be presented as an augmented reality representation in addition to real-life objects.

[0022] The recommendation can also be visualized as a selection of possible distances between the motor vehicle and at least one other motor vehicle. The distances can be shown on the aforementioned head-up display and / or on the (touch) display. The display on the head-up display is particularly suitable for assisting a vehicle occupant in navigating their vehicle to the desired position. If a touch display is used as the display device, further advantages arise. For example, it can be intended that the vehicle occupant wishes to select a specific distance from the selection. They can do this easily via touch operation. If the motor vehicle is a (semi-)autonomous motor vehicle, the motor vehicle can then navigate independently or with assistance to the position corresponding to the selected distance.

[0023] The invention further relates to a driver assistance system for a motor vehicle, wherein the driver assistance system is configured to detect a current airflow situation of the motor vehicle and to determine an actual vehicle state resulting from the current airflow situation, wherein the actual vehicle state comprises an actual noise level in an interior of the motor vehicle. The driver assistance system is further configured to generate a recommendation for a driving maneuver to approximate the actual vehicle state to a desired vehicle state, wherein the desired vehicle state comprises a desired noise level in the interior of the motor vehicle.

[0024] Furthermore, the invention relates to a motor vehicle with such a driver assistance system.

[0025] The invention also includes further developments of the driver assistance system according to the invention and / or the motor vehicle according to the invention that have features as already described in connection with the further developments of the method according to the invention, and vice versa. For this reason, the corresponding further developments of the driver assistance system according to the invention and / or the motor vehicle according to the invention are not described again here.

[0026] The invention also encompasses combinations of the features of the described embodiments. Further features of the invention can be derived from the following description of the figures and from the drawings. The features and combinations of features mentioned above in the description, as well as the features and combinations of features shown below in the description of the figures and / or in the figures alone, can be used not only in the respective specified combination, but also in other combinations or on their own, without departing from the scope of the invention.

[0027] The drawing shows: Fig. 1 a schematic representation of a driver assistance system; Fig. 2 a schematic representation of a motor vehicle with a driver assistance system; Fig. 3 a schematic representation of the relationship between air resistance and wind noise as a function of the distance between a motor vehicle and a motor vehicle driving ahead; Fig. 4 a schematic representation of a possible visualization of a recommendation for a vehicle maneuver; Fig. 5 a schematic representation of another possible visualization of a recommendation for a vehicle maneuver; Fig. 6 a schematic representation of a digital slider for setting a weighting between different parameters; Fig. 7 a schematic representation of a method for operating a driver assistance system.

[0028] Identical or functionally equivalent elements are provided with the same reference numerals in the figures.

[0029] Fig. 1 shows a schematic representation of a driver assistance system 10. The driver assistance system 10 can include a central processing unit 12, which can be coupled to a plurality of sensors 14 for detecting a current airflow situation. A sensor 14 can be a camera sensor, an air pressure sensor, or a radar or lidar sensor. The sensors 14 can transmit data 16 describing the airflow situation to the central processing unit 12. The central processing unit 12 can also be coupled to a navigation module 18 and obtain map information 20 from it regarding the current vehicle environment. An aerodynamic model can be implemented in the central processing unit 12, by means of which the airflow situation can be modeled using the data 16 and the map information 20.

[0030] In addition, the central processing unit 12 can be coupled to one or more noise sensors 22, which are designed to detect a background noise G K in a motor vehicle interior and transmit it to the computing unit 12. An acoustic model can be implemented in the central computing unit 12, by means of which the components of the background noise G K can be isolated that result from the airflow situation and not from conversations between vehicle occupants or similar. This can be achieved using frequency filtering. These components therefore form the actual noise level G resulting from the airflow situation (cf. Fig. 3).

[0031] In the central processing unit 12, a recommendation 24 for a driving maneuver can be generated, which can lead to the actual noise level G being adjusted to a target noise level G S to approach.

[0032] Fig. 2 shows, with reference to the information provided in connection with Fig. 1, a schematic representation of a motor vehicle 26 with a driver assistance system 10, a user interface 28, and a display device 30. The recommendation 24 can be displayed on the display device 30 of the motor vehicle 26. The user interface 28 can be designed to be operated by a vehicle occupant via touch input and / or voice input. Using the user interface 28, the vehicle occupant can, for example, generate a weighting rule, wherein the weighting rule determines a weighting between the approximation of the actual noise level G to the target noise level G S and the approximation of one or more actual parameters to the corresponding target parameters (cf. Fig. 6).

[0033] Fig. 3 shows schematically the relationship between air resistance F of a motor vehicle 26, represented here as a force in Newton (N), and the actual noise level G in the interior of the motor vehicle 26 in decibels (dB), in each case as a function of a distance D in meters (m) to a preceding motor vehicle 32 (cf. Fig. 4 and Fig. 5). A dashed line across both diagrams runs through a vertex S, which marks a local maximum of the actual noise level G. From the illustration, it can be seen that at a distance D of essentially ten meters, the force exerted by the air resistance F on the motor vehicle 26 reaches a local minimum, while the actual noise level G at the same position or at essentially the same position assumes a maximum value, marked by the vertex S. In other words, the development of the air resistance F is qualitatively opposite to the development of the actual noise level G with increasing distance D from the preceding motor vehicle 32. In other words, the developments are not necessarily exactly opposite, but essentially so, so that this results in a conflict of objectives for a vehicle occupant.Although the driver may be driving in a position behind another motor vehicle 32 where air resistance F is advantageously minimized or at least reduced, he will have to tolerate a maximum or relatively high actual noise level G due to wind noise at this position. The recognition and the attempt to resolve this conflict of objectives underlie advantageous embodiments of the present invention.

[0034] Fig. 4 shows a possible visualization of a recommendation 24 for a driving maneuver. Fig. 4 shows, by way of example, a situation in which a vehicle occupant looks through a windshield of motor vehicle 26 in the direction of a motor vehicle 32 traveling ahead. Recommendation 24, depicted here as an arrow pointing to a position between motor vehicle 26 and the motor vehicle 32 traveling ahead, is depicted in the example described here in the manner of augmented reality. The driving situation shown here as an example may be based on the situation in which the vehicle occupant has a target noise level G S for a journey. This definition may also be based on a target air resistance value and / or a target range and / or a target vehicle stability. The vehicle occupant may weight the target noise level G Sand the target air resistance and / or the target range and / or the target vehicle stability. According to the defined values ​​for the parameters mentioned and the weighting applied, the recommendation 24 presented here may have been generated. In other words, this means that the values ​​preferred by the vehicle occupants (i.e. the values ​​regarding the target noise level G S and target air resistance and / or target range and / or target vehicle stability) can be achieved or at least approximated if he adjusts his motor vehicle 26 to the Fig. 4 controls the position represented by the circle and the arrow. The weighting itself or a number of parameters to be considered can be determined from the representation of the Fig. 4 cannot yet be removed.

[0035] Fig. 5 shows the same driving situation as the Fig. 4. In contrast to the Fig. The example shown in Figure 4 is set out as Recommendation 24 in the Fig. 5 shows an arrangement of various fields between the motor vehicle 26 and the preceding motor vehicle 32. The fields are divided into two stripes. For example, the development of the actual noise level G can be shown in the right-hand column and the development of the air resistance F in the left-hand column. The darker a field is, the more advantageous the development of the respective parameter can be at the position of the field. The motor vehicle occupant can now independently steer the motor vehicle 26 to the position of a desired field and / or select the desired field on a touchscreen and thus specify a desired position to which the motor vehicle 26 can also steer semi-autonomously or fully autonomously.

[0036] Fig. 6 schematically shows an exemplary input aid 34 for creating a weighting rule. The input aid 24 can be implemented on the user interface 28 of the motor vehicle 26 as a digital slider 36, which can be moved along a bar 38 between a position for the noise level G and a position for the air resistance F. The movement can preferably be continuous. In the example shown here, setting the slider 36 to the far left would correspond to optimizing the method for minimizing noise input, while setting it to the far right would correspond to minimizing air resistance and thus maximizing the possible range of the motor vehicle 26.

[0037] Fig.7 schematically shows a method for operating a driver assistance system 10 for a motor vehicle 26. In a step S1, a current incoming air flow situation of the motor vehicle 26 is detected. In a step S2, an actual motor vehicle state resulting from the current incoming air flow situation is determined, wherein the actual motor vehicle state includes an actual noise level G in an interior of the motor vehicle 26. Finally, in a step S3, a recommendation 24 for a driving maneuver to approximate the actual motor vehicle state to a desired motor vehicle state is generated, wherein the desired motor vehicle state includes a desired noise level G S in the interior of the motor vehicle 26.

[0038] Overall, the examples demonstrate how the invention can provide a method that, based on an incoming airflow situation (vehicle environment and wind conditions or similar), calculates and visualizes the dependence of air resistance on the vehicle position (in particular the aerodynamic sweet spot), the dependence of wind noise on the vehicle position, and a compromise between minimal air resistance and minimal noise set by the driver according to their preferences. The method then supports or implements the achievement of the thus determined sweet spot, if necessary through driver assistance maneuvers, while observing applicable safety aspects. Thanks to the possibility of 3D reconstruction of the incoming airflow, the lateral position (within the lane) can also be optimally adjusted, which can be an influential control variable, particularly in an incoming airflow situation determined by crosswinds. List of reference symbols 10 Driver assistance system 12 computing unit 14 sensors 16 data 18 Navigation module 20 map information 22 Noise sensor 24 Recommendation 26 Motor vehicle 28 User interface 30 Display device 32 preceding vehicle 34 Input assistance 36 digital sliders 38 bars D Distance F Air resistance G Actual noise level G K Background noise G S Target noise level S vertex

Claims

[1] Method for operating a driver assistance system (10) for a motor vehicle (26), comprising the steps - detecting a current flow situation of the motor vehicle (26), - determining an actual motor vehicle state resulting from the current flow situation, wherein the actual motor vehicle state comprises an actual noise level (G) in an interior of the motor vehicle (26), - generating a recommendation (24) for a driving maneuver to approximate the actual vehicle state to a target vehicle state, wherein the target vehicle state has a target noise level (G S ) in the interior of the motor vehicle (26). [2] Method according to claim 1, wherein the actual motor vehicle state for at least one additional parameter comprises an actual value and the target motor vehicle state for the at least one additional parameter comprises a target value, wherein in generating the recommendation (24) according to a weighting rule, a distinction is made between reaching the target noise level (G S ) and reaching the target value of at least one additional parameter. [3] Method according to claim 2, wherein the at least one additional parameter is an air resistance (F) and / or a range and / or a vehicle stability of the motor vehicle (26). [4] Method according to one of claims 2 or 3, wherein the weighting rule is created based on a user input from a vehicle occupant. [5] Method according to one of the preceding claims, wherein the recommendation (24) is visualized on a display device (30) of the motor vehicle (26). [6] Method according to claim 5, wherein the display device (30) is designed as a head-up display. [7] Method according to one of the preceding claims, wherein the recommendation (24) is visualized as a selection of possible spatial positions of the motor vehicle (26) with respect to objects present in a vehicle environment. [8] Method according to one of the preceding claims, wherein the recommendation (24) is visualized as a selection of possible distances (D) between the motor vehicle (26) and at least one further motor vehicle (32). [9] Driver assistance system (10) for a motor vehicle (26), wherein the driver assistance system (10) is designed to - to record a current flow situation of the motor vehicle (26), - to determine an actual motor vehicle condition resulting from the current flow situation, wherein the actual motor vehicle condition comprises an actual noise level (G) in an interior of the motor vehicle (26), and - to generate a recommendation (24) for a driving maneuver to bring the actual vehicle state closer to a target vehicle state, the target vehicle state having a target noise level (G S ) in the interior of the motor vehicle (26). [10] Motor vehicle (26) with a driver assistance system (10) according to claim 9.

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