Motor vehicle with an acoustic warning device, and method for operating an acoustic warning device

Abstract

Motor vehicle (1) with an acoustic warning device (3), the warning device (3) comprising: - at least one sound generating device (12) configured to output a sound signal (4) in dependence on at least one main emission direction (17) set by a control signal (13) in a respective mechanically predetermined output direction (16) of at least one sound generating element (15), - a control unit (9) arranged to control the sound generating device (12), and - a sensor device (5) configured to detect a respective position (7) of at least one road user (2) in an environment (6) of the motor vehicle (1) for the control unit (9), wherein the control unit (9) is configured to generate the control signal (13) for outputting the acoustic signal (4) in a direction of the respective position of the at least one road user (11) as the at least one set main emission direction (17) and to control the sound generating device (12) by means of the control signal (13) to output the acoustic signal (4), wherein the sensor device (5) is configured to detect a category of the road user (2) by means of a classification method and to recognize, based on a floor plan of the road user (2), whether the category is a pedestrian, a cyclist, or a motor vehicle, wherein the sensor device (5) is configured toto select the acoustic signal (4) from several predetermined acoustic signals (4) depending on the category of the road user (2), wherein , - a) the control unit (9) is designed to emit a louder and lower-frequency sound signal (4) for a motorcyclist than for a cyclist, because it is assumed that the sound signal (4) is dampened by the motorcyclist's helmet and superimposed with the operating noise of the motorcycle, and / or - b) the sensor device (9) is designed to provide a subdivision of the convertible or off-road vehicle categories in the automobile category for more precise identification.

Description

[0001] The invention relates to a motor vehicle with an acoustic warning device and a method for operating the acoustic warning device.

[0002] Electric vehicles are particularly characterized by their silent operation. However, this results in an increased risk of accidents, because pedestrians or cyclists cannot hear an approaching electric vehicle. Despite the increased risk of accidents, the advantages of silent driving, which are particularly evident in urban areas, should not be abandoned. To increase road safety, it is planned, and in some countries legally required, to equip new electric vehicles with an acoustic warning system, also known as AVAS (Acoustic Vehicle Alert System). These are sound-generating devices that emit sound signals, for example, imitating engine noise, to acoustically alert other road users to the presence of the vehicle.A general, non-specific noise emission in all directions from a motor vehicle in order to draw attention to the vehicle is not a satisfactory solution because it causes unnecessary noise pollution.

[0003] For this reason, it is preferable to use sound-generating devices that limit noise emissions to specific situations or road users.

[0004] According to the state of the art, the following devices exist to enable a directed output of sound signals: US 2010 / 0 231 368 A1 discloses a vehicle presence detection device. The device is configured to use an ultrasonic wave as a carrier wave for a perceptible sound. The ultrasonic wave is emitted through a loudspeaker. During propagation of the emitted ultrasonic waves in air, they are partially demodulated and perceptible to humans. Like the ultrasonic wave, the perceptible sound is spatially directed. This makes it possible to emit the acoustically perceptible sound only in a predetermined direction, in which potentially endangered road users are located. US Pat. No. 8,217,766 B2 discloses a motor vehicle presence notification system comprising a plurality of ultrasonic loudspeakers for generating a perceptible sound. It is provided that at least one of the loudspeakers is configured to detect ultrasonic waves. CN 106 114 352 A discloses a motor vehicle-based warning method. The method provides for the immediate vicinity of a motor vehicle to be examined for objects to be warned. If an object to be warned is located in the area, a warning signal is emitted. The warning signal is generated depending on the degree of danger. The degree of danger describes the danger posed to a pedestrian by the motor vehicle. Depending on the degree of danger, the acoustic signal is initially emitted in all directions and, at a higher degree of danger, in one direction of the pedestrian. The acoustic signal is aligned using a beamforming method.

[0005] A disadvantage of these inventions is the alignment of the sound signals using beam-forming techniques. This places greater demands on the sound-generating elements, making production and control more complex.

[0006] DE 10 2010 043 212 A1 discloses an acoustic warning device for an electric vehicle that can emit an acoustic warning signal directed at a potentially endangered road user. Object detection can also be performed, for example, using a thermal imaging camera to distinguish between pedestrians, cyclists, motorcyclists, and other vehicle drivers.

[0007] It is also known from DE 2004 044 517 A1 and DE 10 2009 037 170 A1 to wipe off an acoustic warning signal directed at road users in order to make the warning signal audible only for these road users.

[0008] DE 10 2011 121 284 A1 discloses a method and a device for generating artificial driving noises of a motor vehicle. DE 10 2014 207 399 A1 discloses a device and a method for managing accident risk situations involving living beings.

[0009] DE 10 2010 027 810 A1 describes a method and control unit for driving noise adaptation.

[0010] DE 10 2010 006 633 A1 describes a device for generating warning signals for silent or low-noise motor vehicles with environmental detection.

[0011] It is an object of the invention to provide a solution which makes it possible to limit the sound emission of sound signals to vulnerable road users.

[0012] According to the invention, a motor vehicle is provided with an acoustic warning device. The warning device has at least one sound generating device, a control unit, and a sensor device. The at least one sound generating device is configured to output a sound signal in a respective mechanically predetermined output direction of at least one sound generating element as a function of at least one main emission direction set by a control signal. The control unit is configured to control the sound generating device by means of the control signal. The acoustic warning device has a sensor device configured to detect a respective position of at least one road user in an environment of the motor vehicle for the control unit. A characteristic of the invention is that the control unit is configured to generate the control signal for outputting the sound signal.The control unit is configured to control the sound generating device to output the sound signal in a direction of the respective position of the at least one road user.

[0013] In other words, the invention relates to a motor vehicle equipped with a warning device for informing at least one road user in the vicinity of the motor vehicle of the presence of the motor vehicle by emitting an acoustic signal as a warning signal. The warning device comprises a sound generating device configured to emit the acoustic signal. The acoustic signal is emitted in at least one main emission direction, which is dependent on a control signal. At least one main emission direction means that the acoustic signal is emitted in multiple main emission directions if it is to be emitted to multiple road users who are each in different positions. The control signal is generated by the control unit and used by the control unit to control the sound generating device.To generate the required control signal, the control unit is configured to receive the respective position of the at least one road user to be warned from the sensor device. The sensor device is configured to detect the at least one road user and their respective position in an external environment of the motor vehicle. The core of the invention is that the control unit controls the sound generation device such that the at least main radiation direction coincides with the respective direction of the position of the at least one road user detected by the sensor device.If there are multiple road users, it can also be provided that the control unit controls the sound-generating device such that at least one sound signal is emitted in several main emission directions, which correspond to the respective directions of the positions of the road users detected by the sensor device. To emit the sound signal, the sound-generating device has the sound-generating element. However, the sound-generating element is configured or limited to emitting the sound signal in a respective mechanically predetermined output direction.

[0014] The invention provides the advantage that the acoustic signal can be issued specifically for a road user to be warned, thus enabling a selective warning of individual road users.

[0015] The invention can, for example, relate to a motor vehicle, which can be designed as a passenger car or a truck. The motor vehicle can have the acoustic warning device to alert other road users to its presence. The motor vehicle can, in particular, be an electrically powered motor vehicle or a hybrid motor vehicle, which does not emit any significantly perceptible driving noise and thus requires the acoustic warning device to compensate for the combustion engine noise. The sound generating device can have at least one sound generating element. This can be a loudspeaker which can emit sound signals in a main radiation direction. The main radiation direction can describe a direction of a solid angle in which the sound pressure level has a value which is higher than in another direction.The sound generating device can be configured so that the sound signal can be emitted in an adjustable main radiation direction. The sound generating device can be controlled by the control unit to determine this.

[0016] The control unit can, for example, comprise a microcontroller or a microprocessor. In order to transmit the control signal from the control unit to the sound generating device, the control unit can be connected to the sound generating device via a cable or wirelessly. The sensor device can, for example, comprise cameras for detecting visible light, infrared, lidar, radar or ultrasonic sensors as sensor units. By means of the sensor units, the sensor device can detect a close range, which can be located in the external environment of the motor vehicle. The sensor device can comprise a microprocessor or a microcontroller, which are configured to evaluate the data detected by the sensor units and to identify road users, as well as to determine their position from the detected data.The detected position can, for example, describe a relative position of the road user in relation to the motor vehicle or an absolute position. The absolute position can, for example, be specified in earth coordinates. Thus, in conjunction with GPS signals, which can be used to determine the position of the motor vehicle, it may be possible to determine the earth coordinates of the other road user. In conjunction with geographical data, which can be stored in a navigation system, it may be possible, for example, to determine whether the other road user is on a road or on a pedestrian path. The control unit can be configured to control the sound generating device and its individual sound generating elements such that they emit the sound signal in the main radiation direction, in the direction of the road user's position.The main emission direction can, for example, be the direction of the main cone of the sound signal or a spatial area that has a predetermined intensity of a sound pressure level. The sound generating elements can be configured to emit the sound signal in the mechanically predetermined output direction.

[0017] The invention provides that the sensor device is configured to detect a category of the road user by means of a classification method and to select the acoustic signal of the category of the road user from a plurality of predetermined acoustic signals.

[0018] In other words, the sensor device is configured to assign the road user to a category. The road user's category can be determined using the classification procedure. Depending on the category assigned to the road user by the sensor device, the respective acoustic signal intended for that specific category can be selected.

[0019] This has the advantage that a sound signal can be emitted which is most easily perceived by a specific category of road user.

[0020] For example, it can be provided that the sensor device is configured as a camera that can detect light in the visible or infrared range. The sensor device can comprise a processor configured to evaluate detected signals from the sensor device using a classification method. The classification method can be an image recognition method, for example. If a road user is detected, it can be determined, for example based on a floor plan of the road user, whether the category is a pedestrian, a cyclist, or a motor vehicle. Several different predetermined sound signals can be stored in the control unit, which can be assigned to a respective category of road user. The sound signals can differ from one another, for example, in their volume or frequency range.If the control unit receives a signal from the sensor device, which may include the position of the road user as well as their category, the control unit can select the predetermined sound signal and control the sound generation device such that the predetermined sound signal is transmitted to the road user. For example, it may be provided that a sound signal for a motor vehicle has a higher volume and a lower frequency range than a sound signal predetermined for a pedestrian.

[0021] The direction of the position of the at least one road user can, for example, be the direction of the respective position of the at least one road user relative to the motor vehicle, the sound-generating device, or one of the sound-generating elements. A respective output direction can be the direction in which a respective sound-generating element can emit the sound signal. A respective main emission direction can be the direction in which the sound signal is emitted by the sound-generating device.

[0022] A further development of the invention provides that the sound generating device has at least two sound generating elements with a respective mechanically unchangeable predetermined output direction, wherein the sound generating device is designed to output the sound signal via the sound generating element whose respective mechanically predetermined output direction encloses a minimum angle with the predeterminable main radiation direction.

[0023] In other words, the sound-generating device comprises at least two sound-generating elements. Each of the sound-generating elements has a mechanically unchangeable predetermined output direction and is oriented in a respective direction. If the sound-generating device is controlled by the control unit to emit the sound signal in the predeterminable main emission direction, the sound-generating device determines a respective angle that encloses the respective emission direction of a sound-generating element with the predeterminable main emission direction. The sound signal is then emitted by the sound-generating element whose respective output direction has the minimum angle of the at least two sound-generating elements.

[0024] This has the advantage that the warning signal is emitted via the optimally aligned sound generating element.

[0025] For example, the sound-generating device may comprise an arrangement of multiple sound-generating elements, each of which has a mechanically predetermined output device. The individual output directions of the respective sound-generating elements may differ from one another, allowing the warning signal to be output in different directions. To output the sound signal in the predeterminable main emission direction, the sound-generating element with an output direction closest to the predeterminable main emission direction is selected. This is the sound-generating element whose output direction encloses a minimal angle with the predeterminable main emission direction.

[0026] A further development of the invention provides that the sound generating device has at least one actuator which is designed to orient the at least one sound generating element into an output position, wherein the respective mechanically predetermined output direction of the sound generating element in the output position is aligned in the set main radiation direction.

[0027] In other words, the sound-generating device is configured to enable the emission of the sound signal in the predeterminable main emission direction by aligning the at least one sound-generating element by the actuator such that the output direction of the sound-generating element is aligned with the set main emission direction. For example, the motor vehicle may have an electromechanically operated element as an actuator on which the sound-generating element is arranged. The actuator may be configured to change the orientation of the sound-generating element by means of rotational movements.If the sound generating device is controlled by the control signal and thus the set main radiation direction is specified, it can be provided that the actuator aligns the sound generating element in such a way that the specified output direction of the sound generating element is aligned in the direction of the set main radiation direction.

[0028] A further development of the invention provides that in the sound generating device, the possible output of the sound signal is limited to a predetermined angular range of the vehicle environment and the control unit is configured to control the sound generating device by means of the control signal only when the position of the road user is in a predetermined local area of ​​the predetermined angular range of the vehicle environment.

[0029] In other words, the acoustic warning device is configured to emit the warning signal only when the road user is within the predetermined local area. This provides the advantage of warning a road user when they are in a vulnerable position.

[0030] For example, it can be provided that the sound generating device is configured to emit the sound signal within the predetermined angular range of the vehicle's surroundings. It is thus possible to transmit the sound signal to a road user who is located within the predetermined angular range. However, the control unit can be configured such that the sound signal is only emitted to the road user when they are located within the predetermined local area. The local area can, for example, be an angular range oriented in the direction of travel of the motor vehicle. However, the local area can also be defined absolutely and refer, for example, to a sidewalk.It can thus be provided that a road user is only warned by the acoustic signal if they are on a sidewalk that runs alongside the road on which the motor vehicle is traveling. It can be provided that a road user who is in a different situation in the same geometric relationship to the motor vehicle is not warned by the warning signal because they are, for example, in an area separated from the road by a fence. Thus, no hazardous situation exists. This also eliminates the need to inform the road user by means of the warning sign.

[0031] A further development of the invention provides that the control unit is configured to calculate a hazard value for a respective road user and to control the sound generator device by means of the control signal when the respective hazard value exceeds a predetermined threshold value.

[0032] In other words, the control unit is configured to determine how endangered a respective road user is by the motor vehicle and / or how high the probability is that a dangerous situation will arise between the road user and the motor vehicle. The control unit is configured to quantify the danger using the danger value. The predetermined threshold value for the danger value is stored in the control unit and describes the danger value above which a warning to the respective road user is necessary. The control unit is configured to compare the respective danger value with the predetermined threshold value and to initiate the output of the warning signal by the sound generator device using the control signal if the danger value is greater than the predetermined threshold value.

[0033] This has the advantage that only road users who may be endangered by the vehicle are warned.

[0034] For example, it can be provided that the sensor device tracks the movement of a road user and transmits it to the control unit. The control unit can, for example, perform an extrapolation using predetermined behavioral models in order to predict the road user's future movement. The behavioral models can depend, for example, on the type of road user detected, which includes a pedestrian or a cyclist. The risk value can, for example, depend on the distance of the predicted movement of the road user from a road on which the motor vehicle is traveling or the planned route of the motor vehicle's autopilot.A road user moving away from the road of the motor vehicle can be assigned a lower hazard value by the control unit than a road user approaching the road of the motor vehicle. It can be provided that the hazard value of a road user whose movement path, according to the extrapolation, will enter the road of the motor vehicle exceeds the threshold value. The control unit can be configured so that, when the threshold value is exceeded, the output of the control signal is initiated to warn the road user.

[0035] A further development of the invention provides that the control unit is designed to adjust a volume of the sound signal depending on a time of day and / or a day of the week.

[0036] In other words, the volume of the sound signal depends on the current time and / or the current day of the week.

[0037] This has the advantage of reducing noise pollution at night and on holidays.

[0038] For example, the control unit can store information about which value can be used for the volume of the audible signal on which day of the week and / or at which time of day. For example, the permissible volume can be lower on a Sunday than on a Tuesday. The permissible volume can be lower at night than in the afternoon.

[0039] A further development of the invention provides that the control unit is designed to adjust the volume and / or a frequency of the sound signal depending on a speed or a direction of travel of the motor vehicle.

[0040] In other words, the volume and / or frequency of the sound signal depends on the speed at which the motor vehicle is moving and / or the direction of travel of the motor vehicle.

[0041] This has the advantage that the road user can be informed about the speed and / or speed of the vehicle by means of the acoustic signal.

[0042] For example, the use of an electric motor may mean that the motor vehicle does not produce any audible noises that would allow road users to estimate the speed and / or direction of travel of the motor vehicle. To compensate for this, the acoustic signal may imitate an internal combustion engine, with the volume and / or frequency of the acoustic signal depending on the speed of the motor vehicle, as is the case with an internal combustion engine. The acoustic signal may also depend on whether the motor vehicle is moving forwards or backwards. The acoustic signal may thus inform road users about the speed and direction in which the motor vehicle is moving.

[0043] A further development of the invention provides that at least one sound generating element is configured to modulate the sound signal to an ultrasonic carrier frequency, wherein the control unit is configured to adjust the ultrasonic carrier frequency as a function of a distance of the position of the road user from the respective sound generating element in the predeterminable main radiation direction.

[0044] In other words, a sound-generating element is an ultrasonic element that emits the warning signal. The sound signal is a sound signal in the ultrasonic range, onto which an audible sound signal is modulated. The frequency of the ultrasonic signal is adjusted by the control unit depending on the distance of the road user from the sound-generating element.

[0045] This has the advantage of enabling a distance-dependent output of the sound signal for the road user.

[0046] For example, it can be provided that at least one sound-generating element is a loudspeaker having a membrane made of glass, diamond, hardened steel, or ceramic. The sound-generating element is thus configured to emit sound in the ultrasonic range. Due to non-linear propagation effects of the ultrasonic signal, demodulation can take place, so that the sound signal becomes audible after a frequency-dependent propagation length. The control unit can be configured to adjust the ultrasonic frequency depending on the distance of the road user, so that the sound signal becomes audible at the position of the road user. The ultrasonic frequency can be used as a carrier frequency, whereby the audible sound signal can be modulated onto the ultrasonic frequency.

[0047] The invention also encompasses a method for operating a motor vehicle with an acoustic warning device. In a first step, a sensor device of the acoustic warning device detects the position of a road user in the surroundings of the motor vehicle for a control unit of the acoustic warning device. The control unit generates a control signal for emitting an acoustic signal in a direction corresponding to the position of the road user as at least one set main emission direction. The sound generating device is controlled by the control unit using the control signal. The sound generating device emits the acoustic signal in at least one main emission direction set by the control signal using at least one sound generating element.The sound signal is output by at least one sound generating element in a mechanically predetermined output direction of the at least one sound generating element.

[0048] In other words, in a first step, a road user located in the vicinity of the motor vehicle is detected by the sensor device. The position of the road user is transmitted from the sensor device to the control unit. In order to be able to emit the sound signal in the direction of the road user's position, a control signal is generated by the control unit. The control signal is used by the control unit to actuate the sound generating device. Based on the control signal, the sound generating device emits the sound signal in the at least one set main emission direction. The sound signal is emitted by means of the at least one sound generating element, with the output occurring in a mechanically predetermined output direction of the sound generating element.

[0049] This has the advantage of enabling a directed sound signal to be emitted to a road user.

[0050] For example, it can be provided that a road user is located in the vicinity of the motor vehicle and is detected by the sensor device of the acoustic warning device. The sensor device can determine the position of the road user and transmit a signal to the control unit. The control unit can calculate a direction that the road user has with respect to a sound-generating element of the sound-generating device. The control unit can transmit the direction to the sound-generating device in order to output a sound signal. The sound-generating device can output the sound signal in the set main radiation direction, wherein the sound signal is output in the mechanically predetermined output direction of the at least one sound-generating element.

[0051] The invention also includes combinations of the features of the described embodiments.

[0052] The invention also includes further developments of the method according to the invention that have features already described in connection with the further developments of the motor vehicle according to the invention. For this reason, the corresponding further developments of the method according to the invention are not described again here.

[0053] Exemplary embodiments of the invention are described below. Shown are: Fig. 1 an embodiment of the motor vehicle; Fig. 2 shows a further embodiment of the motor vehicle; Fig. 3 shows a further embodiment of the motor vehicle; Fig. 4 a possible mode of operation of the motor vehicle; and Fig. 5 a possible course of the procedure.

[0054] The exemplary embodiments explained below are preferred embodiments of the invention. In the exemplary embodiments, the described components of the embodiments each represent individual features of the invention that can be considered independently of one another, each of which also develops the invention independently of one another. Therefore, the disclosure is intended to encompass combinations of the features of the embodiments other than those shown. Furthermore, the described embodiments can also be supplemented by further features of the invention already described.

[0055] In the figures, the same reference symbols designate elements with the same function.

[0056] Fig. 1 shows a possible embodiment of the motor vehicle 1 according to the invention. The motor vehicle 1 according to the invention can have the acoustic warning device 3. The motor vehicle 1 can, for example, be an electrically powered passenger vehicle or an electrically powered truck. Due to the electric drive of the motor vehicle 1, the problem can arise that nearby road users 2 cannot be alerted to the presence of the motor vehicle 1 by engine noise. This can lead to risky situations because the motor vehicle 1 cannot be perceived by the road users 2. In order to alert other road users 2 to the presence of the motor vehicle 1, the motor vehicle 1 can have an acoustic warning device 3. The sound generating device 12 has the task of alerting other road users 2 to the presence of the motor vehicle 1 by means of a sound signal 4.The acoustic warning device 3 can have a sensor device 5, which can be, for example, a camera, a radar sensor, a lidar device, or an infrared sensor. The sensor device 5 can monitor an environment 6 of the motor vehicle 1 and detect a road user 2 located in the environment 6 and their position 7. The position 7 of the other road user 2 can be determined, for example, using image analysis methods. The sensor device 5 can transmit a detection signal 8 to a control unit 9, in which, for example, a category 10 and the position 7 of the road user 2 are described. The category 10 of the road user 2 can be, for example, the category pedestrian, cyclist, or motor vehicle. The category 10 of the road user 2 can be determined, for example, using a recognition method of the sensor device 5.This can be, for example, an image recognition algorithm. The control unit 9 can, for example, be a processor configured to generate the control signal 13, which describes the direction 11 that the road user 2 can have with respect to a sound generating device 12. The control unit 9 can, for example, also describe a volume and a frequency of the sound signal 4 in the control signal 13. The volume and frequency of the sound signal 4 can depend on the category 10 of the road user 2 and / or the day of the week and / or the time of day. In order to be able to output a sound signal 4 to the other road user 2, the control unit 9 can be configured to transmit the control signal 13 to the sound generating device 12 and thus to be able to control the sound generating device 12.The sound generating device 12 can have one or more sound generating elements 15, wherein a respective sound generating element 15 is configured to emit the sound signal 4 in a respective output direction 16. The output direction 16 of a respective sound generating element 15 can be predetermined due to the geometric and / or mechanical properties of the respective sound generating element 15. The sound generating device 12 can be configured to output the sound signal 4 in an adjustable main emission direction 17. It can be provided that it is not possible to output the main emission direction 17 continuously in all directions. In this case, it can be provided that the sound signal 4 is output in an output direction 16 of the sound generating element 15 that is closest to the direction of the other road user 11.For this purpose, an angle 14 can be calculated between the direction of the road user 11 and the respective output directions 16 of the individual sound-generating elements 15. The angle a, which has the smallest value, is determined as the direction for the output of the sound signal 4 of the respective sound-generating element 15.

[0057] Fig. 2 shows a further possible embodiment of the motor vehicle 1 according to the invention. In the illustrated development of the motor vehicle 1 according to the invention, it can be provided that the sound generating device 12 has an actuator 18, which can be arranged on the sound generating element 15. The actuator 18 can be configured to change the orientation of the sound generating element 15. It can be provided that the sound generating element 15 can be oriented by the actuator 18 along a predetermined angular range 19. It can be provided that in the event that another road user 2 is detected in the environment 6 of the motor vehicle 1 and the detection signal 8 is transmitted by the sensor device 5 to the control unit 9.The control unit 9 can control the sound generating device 12 by means of the control signal 13 such that the sound generating element 15 is aligned by the actuator 18 so that the output direction 16 of the sound generating element 15 and thus the main radiation direction 17 is aligned in the direction of the road user 2. The sound signal 4 can thus be emitted to the road user 2. It can be provided that the sound signal 4 is only output by the sound generating device 12 when the road user 2 is located in a predetermined danger zone 20. The predetermined danger zone 20 can, for example, be an area in which the road user 2 may be endangered by the motor vehicle 1. It can, for example, be an area in a direction of travel of the motor vehicle 1. It can be provided that a distance 21 of the road user 2 from the sound generating element 15 is determined.This can be done, for example, by the sensor device 5. The control unit can generate the control signal 13 and control the sound generating device 12 such that the sound generating element 15 generates a carrier frequency in the ultrasonic range, which is demodulated through the air as it travels along the distance to the other road user 2, whereby the sound signal 4 only becomes audible at the position of the road user 7. This has the advantage of avoiding unnecessary disturbance to the surroundings by the sound signal 4. The sound generating element 15 can, for example, be a directional sound generator having a glass surface, a ceramic surface, or a surface made of a hardened alloy, which is excited to vibrate by a driver.

[0058] Fig. 3 shows a further possible embodiment of the motor vehicle according to the invention, wherein the sound-generating device 12 can have a plurality of sound-generating elements 15, which can be arranged at different positions on a body of the motor vehicle 1. The sound-generating elements 15 can differ from one another in their orientation, so that the sound signal 4 can be emitted by the sound-generating device 12 into the surroundings 6 of the motor vehicle 1. In this case, the control unit 9 can be configured to control the sound-generating element 15 that is oriented in the direction of the road user 2.

[0059] Fig. 4 shows a possible mode of operation of the motor vehicle 1 according to the invention in a possible traffic situation. The figure shows two possible embodiments of the motor vehicle 1 according to the invention in road traffic. The two motor vehicles 1 can have the sound generating device 12. It may be possible that several other road users 2 are present in the traffic situation, who may not be able to acoustically perceive the motor vehicles 1. The invention is intended to make it possible for only certain road users 2 to be informed of the presence of the motor vehicle 1 by means of the sound signal 4. Other road users 2 should not perceive the sound signal 4 or should only perceive it to a limited extent. The sensor device 5 of the respective motor vehicles 1 can detect the road users 2 and determine their position.It can be provided that the respective danger zones 20 are determined by the respective motor vehicles 1. The danger zones 20 can depend on a geographical position of the road user 2 or a relationship between the position of the road user 2 and that of the motor vehicle 1. In the latter case, the size or position of the danger zone 20 can, for example, depend on a speed and / or direction of travel of the motor vehicle 1. It can, for example, be arranged in the direction of travel of the motor vehicle 1 and have an area that is proportional to the driving speed. It can, for example, be a circular sector whose angle bisector points in the direction of travel and whose radius has a predetermined relationship to the speed.It can be provided that the control unit 9 generates control signals 13 which cause the acoustic signal 4 to be output only to those road users 2 who are located in the danger zone 20. It can also be provided that the danger zones 20 are determined on the basis of an absolute position of the other road user 2. This can, for example, be a method which takes into account navigation data and / or map data of the surroundings of the motor vehicle 1 and in which, for example, streets and / or sidewalks are stored. If one of the road users 2 is, for example, on a sidewalk in the surroundings 6 of the motor vehicle 1, they can be located in the danger zone 20 because sidewalks on a road can be specified as danger zones 20.If one of the road users 2 is, for example, at a window or in a green area, it can be provided that this person is located outside the danger zone 20, because green areas or built-up areas cannot be specified as danger zones. In this case, it can be provided that the control unit 9 does not generate a control signal 13 for transmitting the acoustic signal 4 to the respective road user 2. In order to emit acoustic signals 4 in traffic that only warn the respective endangered road user 2, it can be provided that the acoustic signal 4 is emitted in an output direction 16 that is aligned in the direction of the position of the road user 7. It can be provided that a modulation of the acoustic signal 4 onto an ultrasonic wave, which can act as a carrier wave, takes place. The ultrasonic wave can be adjusted depending on the distance 21 of the road user 2 from the sound generating element 15.The ultrasonic wave can demodulate during propagation in the air over the distance 21, so that the acoustic signal 4 is only audible at the position of the road user 7. Thus, the acoustic signal 4 is not audible to road users 2 who are outside the main radiation direction 17. A specific warning for individual road users 2 is thus possible. It can also be provided that the nature of the acoustic signal 4 depends on the category of the road user 2. It can be provided that the sensor device 5 can recognize the category of the respective road user 2 by means of a classification method, which can be an image recognition algorithm, in order to enable the output of category-specific acoustic signals 4. The category-specific acoustic signals can be stored in the control unit 9 and specify a respective volume and / or frequency for the acoustic signal 4.The specification should be aimed at improving the perception of the acoustic signal by the addressed road user 2. Possible categories include pedestrians, cyclists, motorcyclists or automobiles. A subdivision of the categories, such as convertible or off-road vehicle in the automobile category, can be provided for more precise identification. For example, it can be provided that a louder and lower-frequency acoustic signal 4 is emitted for a motorcyclist than for a cyclist because it can be assumed that the acoustic signal 4 is muffled by the motorcyclist's helmet and that it is masked by the operating noise of the motorcycle. It can also be provided that the warning to a particular road user is dependent on a risk value for the respective road user 2.This can, for example, depend on a planned route of an autopilot. A movement of road user 2 can also be detected by sensor device 5 and transmitted to control unit 9. The hazard value can, for example, depend on whether road user 2 is moving toward motor vehicle 1. Control unit 9 can extrapolate the movement of road user 2. The hazard to road user 2 can be quantified using the hazard value and compared with a threshold value. If the hazard value is greater than the threshold value, an acoustic signal can be output to road user 2.

[0060] Fig.5 shows a possible sequence of an embodiment of the method. In the surroundings of the motor vehicle 6, the road user 2 can be detected by the sensor device 5 of the acoustic warning device 3 in a first step P1. The road user 2 can be located in the danger zone 20, so that the control unit 9 generates the control signal 13 in a second step P2 in order to be able to warn the road user 2 by means of the acoustic signal 4. The control signal 13 can contain the direction 7 in which the other road user 2 is located. The control signal 13 can specify a frequency or volume of the acoustic signal 4, which can depend on the direction of travel or the speed of the motor vehicle 1. In a next step P3, the control unit 9 can control the warning device 3 by means of the control signal 13.In step P4, the sound signal 4 can be output by the sound generating device 12 in the at least one main emission direction 17 set by the control signal 13 by means of at least one sound generating element 15. The sound signal 4 can be output by at least one sound generating element 15 in a mechanically predetermined output direction of the at least one sound generating element 15 of the sound generating device 12.

[0061] Electric vehicles are particularly characterized by their silent operation. However, this also results in an increased risk of accidents, because pedestrians or cyclists cannot hear an approaching electric vehicle. Nevertheless, one does not want to give up the advantage of silent driving, especially in urban areas, which is why general noise emissions to draw attention to the vehicle are not a satisfactory solution.

[0062] A solution can be provided by a pedestrian or cyclist warning system for electric vehicles, which is also known as an Acoustic Vehicle Alert System (AVAS).

[0063] Modern vehicles are already equipped with sensors (cameras, ultrasonic sensors, lidar, radar, etc.) for piloted or autonomous driving and can detect and classify other road users. This allows the position and direction of a pedestrian or cyclist relative to the vehicle to be calculated.

[0064] The idea is to couple a vehicle-mounted loudspeaker system with directed sound radiation (e.g., engine noise simulation) with the existing detection system. The goal is to achieve sound emission that is as focused as possible on the affected pedestrian, minimizing noise pollution for other people not in the potential danger zone. This would significantly reduce the impact on residents of inner cities with residential areas bordering the streets. Furthermore, the silent driving experience for vehicle occupants is fully preserved, especially in convertibles or vehicles with large roofs.

[0065] Effective sound dispersion can be achieved with a glass speaker. The properties of glass can be utilized in such a way that the transparent pane focuses the sound and radiates it in a straight line. Only those directly within the sound cone can hear the sound. From any other angle, however, virtually nothing is audible.

[0066] While conventional devices have a membrane driven by an electromagnetic coil, thus generating vibrations, i.e., sound, the directional speaker works somewhat differently. Here, ultrasonic waves, i.e., high-frequency sound waves, are generated, which then later convert into audible sound waves after traveling a few meters.

[0067] The products from Hypersound and Akoustic-arts demonstrate that the technology for directional sound emission already exists. Based on this, nothing should stand in the way of further automotive development.

[0068] The vehicle can be equipped with a central segmented loudspeaker. The individual segments are controlled as needed, producing a targeted sound wave directed at the person in question as the vehicle passes by.

[0069] Alternatively, the vehicle can be equipped with a rotatable loudspeaker. The loudspeaker module is mounted on a rotatable mount and can be swiveled in the required direction. This allows the entire area in front of the vehicle to be covered very evenly, because the system can be tracked very precisely.

[0070] The idea is to use a directional sound source, combine it with existing technologies and create an intelligent sound source, analogous to a matrix spotlight.

[0071] Overall, the examples show how the invention enables targeted warnings to individual road users and reduces the impact on the surrounding area.

Claims

[1] Motor vehicle (1) with an acoustic warning device (3), the warning device (3) comprising: - at least one sound generating device (12) configured to output a sound signal (4) in dependence on at least one main emission direction (17) set by a control signal (13) in a respective mechanically predetermined output direction (16) of at least one sound generating element (15), - a control unit (9) arranged to control the sound generating device (12), and - a sensor device (5) configured to detect a respective position (7) of at least one road user (2) in an environment (6) of the motor vehicle (1) for the control unit (9), wherein the control unit (9) is configured to generate the control signal (13) for outputting the acoustic signal (4) in a direction of the respective position of the at least one road user (11) as the at least one set main emission direction (17) and to control the sound generating device (12) by means of the control signal (13) to output the acoustic signal (4), wherein the sensor device (5) is configured to detect a category of the road user (2) by means of a classification method and to recognize, based on a floor plan of the road user (2), whether the category is a pedestrian, a cyclist, or a motor vehicle, wherein the sensor device (5) is configured toto select the acoustic signal (4) from several predetermined acoustic signals (4) depending on the category of the road user (2), wherein, - a) the control unit (9) is designed to emit a louder and lower-frequency sound signal (4) for a motorcyclist than for a cyclist, because it is assumed that the sound signal (4) is dampened by the motorcyclist's helmet and superimposed with the operating noise of the motorcycle, and / or - b) the sensor device (9) is designed to provide a subdivision of the convertible or off-road vehicle categories in the automobile category for more precise identification. [2] Motor vehicle (1) according to claim 1, characterized byin that the sound generating device (12) has at least two sound generating elements (15) with a respective mechanically unchangeable predetermined output direction (16), wherein the sound generating device (12) is designed to output the sound signal (4) via the sound generating element (15) whose respective mechanically predetermined output direction (16) encloses a minimum angle (14) with the respectively predetermined main radiation direction (17). [3] Motor vehicle (1) according to one of the preceding claims, characterized by in that the sound generating device (12) has at least one actuator (18) which is designed to orient the at least one sound generating element (15) into an output position, wherein the respective mechanically predetermined output direction (16) of the sound generating element (15) in the output position is aligned in one of the at least one set main radiation direction (17). [4] Motor vehicle (1) according to one of the preceding claims, characterized by in that in the sound generating device (12) the possible output of the sound signal is limited to a predetermined angular range (19) of the vehicle surroundings (6), and the control unit (9) is designed to control the sound generating device (12) by means of the control signal (13) only when the respective position of the at least one road user (7) is in a predetermined local danger zone (20) within the predetermined angular range (19) of the vehicle surroundings (6). [5] Motor vehicle (1) according to one of the preceding claims, characterized by that the control unit (9) is designed to calculate a hazard value for a respective road user (2) and to control the sound generating device (12) by means of the control signal when the respective hazard value exceeds a predetermined threshold value. [6] Motor vehicle (1) according to one of the preceding claims, characterized by that the control unit (9) is designed to adjust a volume of the sound signal (4) depending on a time of day and / or a day of the week. [7] Motor vehicle (1) according to one of the preceding claims, characterized by that the control unit (9) is designed to adjust the volume and / or a frequency of the acoustic signal (4) as a function of a speed or a direction of travel of the motor vehicle (1). [8] Motor vehicle (1) according to one of the preceding claims, characterized byin that at least one sound generating element (15) is designed to modulate the sound signal (4) to an ultrasonic carrier frequency, wherein the control unit (9) is designed to adjust the ultrasonic carrier frequency as a function of a distance (21) of the respective position of the road user (7) from the respective sound generating element (15) in the predeterminable at least one main radiation direction (17). [9] Method for operating a motor vehicle (1) with an acoustic warning device (3), wherein - at least one position (7) of a road user (2) in an environment (6) of the motor vehicle (1) is detected by a sensor device (5) of the acoustic warning device (3) for a control unit (9) of the acoustic warning device (3), - a control signal (13) for emitting a sound signal (4) in a direction of the respective position of the at least one road user (11) is generated by the control unit (9) as at least one set main emission direction (17), - the sound generating device (12) is controlled by the control unit (9) by means of the control signal (13), - the sound signal (4) is output by at least one sound generating element (15) in a mechanically predetermined output direction (16) of the at least one sound generating element (15), and - the sensor device (5) detects a category of the road user (2) by means of a classification method, characterized bythat the sensor device (5) selects the acoustic signal (4) depending on the category of the road user (2) from a plurality of predetermined acoustic signals (4) and if a road user is detected (2), it is recognized based on a floor plan of the road user (2) whether the category is a pedestrian, a cyclist or a motor vehicle, wherein - a) it is provided that a louder and lower-frequency sound signal is emitted for a motorcyclist than for a cyclist because it is assumed that the sound signal (4) will be dampened by the motorcyclist's helmet and superimposed by the operating noise of the motorcycle and / or - b) a subdivision of the convertible or off-road vehicle categories is provided for in the automobile category for more precise identification.

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