EP3951771A1 - Method, noise cancellation system and vehicle - Google Patents

Abstract

The invention relates to a method for reducing noise pollution in the interior of vehicles, in particular emergency vehicles, with a continuous tone horn. In addition, the invention relates to an anti-noise system for installation in vehicles, in particular emergency vehicles, with a repeating tone horn to reduce noise pollution in the interior of the vehicle. Furthermore, the invention relates to a vehicle, in particular an emergency vehicle, with an anti-noise system.

Description

The invention relates to a method for reducing noise pollution in the interior of vehicles, in particular emergency vehicles, with a continuous tone horn. In addition, the invention relates to an anti-noise system for installation in vehicles, in particular emergency vehicles, with a repeating tone horn to reduce noise pollution in the interior of the vehicle. Furthermore, the invention relates to a vehicle, in particular an emergency vehicle, with an anti-noise system.

Emergency vehicles with a continuous tone horn are known from the prior art. These include in particular police, fire brigade and/or rescue vehicles. A continuous tone horn generally refers to an acoustic device on vehicles that emits several signal tones of different fundamental frequencies one after the other. In Germany, this refers in particular to a special signaling system that is used in authorized (emergency) vehicles of certain authorities and organizations with security tasks, including for aid organizations. The term use or Martinshorn is also used synonymously in Germany for the term follow-up tone horn.

The noise exposure in such emergency vehicles is comparatively high for the vehicle crew due to the acoustic signals emitted by the horn during the operation. This further intensifies the already high physical and mental stress on the crew during an operation. Long-term physical and psychological damage caused by exposure to noise cannot be ruled out either. Noise protection earmuffs can help a little and are sometimes used in fire engines. However, this makes it difficult for the vehicle crew to communicate with each other. In addition, such earmuffs hinder the vehicle crew in their actual task. In particular, earmuffs cannot be used by paramedics as ambulance crews.

In the field of consumer electronics, so-called ANC (Active Noise Canceling) headphones are also known, which use the principle of anti-noise to suppress ambient noise when playing music. Furthermore, the arrangement of loudspeakers in vehicles for the reproduction of radio transmissions, music and/or recently synthetic engine noises is known. In However, these are either not used in emergency vehicles or are always switched off during operations so that the noise pollution is not increased by an additional noise source.

The object of the invention is therefore to reduce the noise exposure caused by continuous tone horn signals inside emergency vehicles.

To achieve the object, the invention proposes a method for reducing noise pollution in the interiors of vehicles, in particular emergency vehicles, with a subsequent tone horn, in which an anti-sound corresponding to the sound waves of the subsequent tone horn is generated in at least one interior of the vehicle.

The solution according to the invention advantageously enables the almost complete suppression of subsequent tone horn noises in the entire interior of the vehicle. In addition, the anti-noise generated advantageously does not impair the ability of the vehicle crew to communicate. This is not because there is no overlap between the sound frequency of the anti-sound and the frequency of human speech. A comparatively large technical effect can be achieved in a comparatively simple manner by the method according to the invention.

For the purposes of the invention, “anti-noise” denotes sound that is artificially generated in order to cancel out sound by means of destructive interference. For this purpose, the aim is to generate a signal that exactly corresponds to that of the interfering sound with the opposite polarity. Anti-noise is also known as anti-noise or active noise cancellation. For the purposes of the invention, the term “interior of a vehicle” denotes an area that can be used by people, in particular the vehicle crew and/or emergency services. In the case of emergency vehicles in the form of cars, this is the passenger area, including the enclosed space with its interior dimensions and the interior panels, seats, benches, dashboard, other fittings and controls. In the case of emergency vehicles in the form of trucks, an interior space can be, in particular, a driver's cab or a separate transport space for people, such as is found in police and fire brigade troop transport vehicles and in ambulances.

In the simplest case, provision is made for generating an anti-sound tuned in advance to the sound waves of a sequential tone horn installed on a specific emergency vehicle in the interior of this vehicle. In this case, there is no dynamic detection of the sound waves to be compensated. Instead, an adjustment to the sound waves can be made on the basis of preliminary measurements or theoretical values. As a result, a reduction in noise pollution in the interior can be achieved with the simplest of means. A simple amplifier and a loudspeaker connected to it, which is installed in the interior of the vehicle, are sufficient for this. In this case, the amplifier preferably has a device for phase shifting and/or inversion. Any on-board speaker can be used as the speaker. The amplifier preferably provides a corresponding connection for this. In this way, existing emergency vehicles can also be advantageously retrofitted with anti-noise technology.

According to a preferred feature of the invention, dynamic detection and generation of anti-noise is provided. For this purpose it is provided to arrange a microphone in the interior of the vehicle. The microphone serves to capture the sound waves of the subsequent tone horn. The quality of the anti-noise and thus its effectiveness can be improved by a more precise adjustment to the noise to be compensated. In addition to this, further background noise and/or frequency tolerances of the subsequent tone horn can preferably also be detected in order to further improve the effectiveness. Basically, the installation of a single microphone in the interior is sufficient. Additional microphones can be installed to further improve effectiveness. However, this increases the complexity of the system. In emergency vehicles in particular, overly complex systems are generally undesirable because of their susceptibility to errors.

The sound waves captured by the microphone can now be modified in an analogous way, in particular phase-shifted and/or inverted, in order to generate the counter-sound. A simple analog amplifier is sufficient for this.

As an alternative or in addition to this, the anti-noise can be generated electronically. For this purpose, the sound waves recorded with the microphone are converted into electronic, in particular digital, signals. By means of a computer unit, in particular in the form of a microcontroller, electronic, in particular digital, Generates signals that are tuned to those signals based on the sound waves of the follow-up horn previously recorded with the microphone. The electronic, in particular digital, signals are then converted into corresponding sound waves with the opposite polarity to the sound waves of the subsequent tone horn and emitted by means of the loudspeaker.

In the same way, interference signals and/or harmonics associated with the noise of the subsequent tone horn can also be detected and compensated for by means of anti-noise. After detection, the interference signals and/or harmonics are converted into electrical signals and then signals with opposite wave polarity are generated.

According to a preferred feature of the invention, it is provided that sound waves in the frequency range from 300 Hz to 700 Hz, in particular 360 Hz to 630 Hz, are compensated for by means of the counter-sound. It has been shown that the generation of anti-noise in this frequency range largely eliminates the disruptive sound waves of the subsequent tone horn in the interior of the vehicle, but does not affect the frequencies that people use to produce speech. The invention advantageously brings about a significant reduction in noise pollution while avoiding impairments to communication. Furthermore, the invention advantageously ensures that the sound waves of the subsequent tone horn can be heard in the normal way outside the interior of the vehicle and can be perceived as a warning signal.

On the device side, the invention also relates on the one hand to an anti-noise system for installation in vehicles, in particular emergency vehicles, with a repeating tone horn to reduce noise pollution in the interior of the vehicle, at least having a loudspeaker that can be installed in the interior of the vehicle to generate an anti-noise corresponding to the sound waves of the repeating tone horn. On the other hand, the invention proposes a vehicle, in particular an emergency vehicle, with a continuous tone horn, having an anti-sound system according to the invention arranged in the interior of the vehicle.

The device-side solution according to the invention also advantageously enables the almost complete suppression of subsequent tone horn noises in the entire interior of the vehicle. In addition, the anti-noise generated advantageously does not impair the ability of the vehicle crew to communicate. This is not because it there is no overlap between the sound frequency of the anti-sound and the frequency of human speech. A comparatively large technical effect can be achieved in a comparatively simple manner by the method according to the invention.

It is preferably provided that at least one microphone is installed in the interior of the vehicle for detecting the sound waves of the subsequent tone horn. Sound spreads out spatially, making it difficult to invert the sound waves throughout the interior and to match the amount everywhere. Therefore, positioning microphones close to the occupant is beneficial. This is because the noise exposure there is to be reduced the most (at certain points). Several loudspeakers could also be used to optimally adjust the cabin or individual seats. In order to improve the sound quality, it may therefore be preferable to install or build in a plurality of microphones in the interior of the vehicle. However, this increases the complexity of the system. In the area of emergency vehicles, it is generally desirable to limit the complexity of a system as much as possible.

According to a preferred feature of the invention, an amplifier and/or a computer unit is provided for converting the recorded sound waves into electronic signals and/or for modifying, in particular phase shifting and/or inverting, the recorded sound waves or the electronic signals. The computer unit also makes it possible to generate artificial signals as a function of the recorded sound waves of the subsequent tone horn. For this purpose, the sound waves of the subsequent tone horn are recorded by the microphone and converted into electronic signals by the computer unit. These signals are then duplicated and processed using phase shifting and/or inversion, resulting in anti-sound with opposite polarity.

According to a preferred feature of the invention, a loudspeaker installed in the interior is provided, with which the anti-sound waves based on the modified sound waves and/or the modified electronic signals can be output in the interior of the vehicle. In this case, essentially the entire interior of the vehicle is exposed to the resulting counter-sound waves. The loudspeaker is therefore designed to expose at least the majority of the volume of the interior of the vehicle to the counter-noise. Conventional speakers can do this be used. For example, those that are already installed in the vehicles at the factory. As an alternative or in addition, supplementary loudspeakers can be provided in order to improve the quality of the anti-noise.

According to a preferred feature of the invention, the at least one loudspeaker is designed as a flat loudspeaker. It has been shown that the interior of vehicles can be exposed to particularly homogeneous sound by means of a flat-panel loudspeaker. This advantageously leads to a particularly effective compensation for the disturbing subsequent tone horn noises. A flat panel loudspeaker is a type of loudspeaker that is attached to surfaces and causes them to vibrate by means of structure-borne noise transmission. For this purpose, voice coils are attached to a panel, which receive an electrically amplified sound signal and transmit it to the respective surface. The at least one flat panel loudspeaker is preferably installed on an interior surface of a window pane, in particular the windshield, and/or on an interior surface of the body/interior.

According to a preferred feature of the invention, the anti-sound system or the vehicle has at least one non-surface loudspeaker, preferably in addition to the surface loudspeaker. While flat-panel loudspeakers ensure homogeneous sound reinforcement, some installations sometimes require targeted sound reinforcement of delimited areas in order to improve the desired effect. Provision is preferably made for this non-flat loudspeaker to be installed in the upper part of a vehicle seat, in particular the headrest. In this way, the ears of the vehicle crew can be exposed to the anti-noise in a targeted manner and its effect can be improved in an advantageous manner.

According to a preferred feature of the invention, at least one microphone, an amplifier and/or a computer unit and a loudspeaker are arranged as a discrete assembly in a common housing. The assembly formed in this way can be installed or arranged anywhere in the interior of the vehicle. The anti-sound system according to the invention can have a plurality of the aforementioned assemblies. This advantageously makes the system very flexible. The assemblies can be arranged directly at such positions in the interior where a particularly good anti-noise effect is desired. For example in the area of the headrests of the vehicle seats or in the area of the roof liner. The assemblies can preferably be fed via the vehicle's electrical system. Alternatively or in addition the assembly can be operated by means of an energy store, in particular a disposable battery or an accumulator.

Fig. 1

eine ausschnitthafte, schematische Darstellung eines erfindungsgemäßen Fahrzeugs mit einem erfindungsgemäßen Gegenschallsystems;

Fig.2

eine Kopfstütze eines im Innenraum des Fahrzeugs nach Figur 1 angeordneten Fahrzeugsitzes aufweisend Teile des erfindungsgemäßen Gegenschallsystem in schematischer Darstellung;

Fig.3

ein erfindungsgemäßes Gegenschallsystem gemäß einer bevorzugten Ausführungsform in schematischer Darstellung;

Fig.4

ein erfindungsgemäßes Gegenschallsystem gemäß einer weiteren bevorzugten Ausführungsform in schematischer Darstellung.

The invention is explained in detail below using exemplary embodiments. The examples serve only to illustrate the invention and are not to be understood as limiting in any way for the person skilled in the art. show:

1

a partial, schematic representation of a vehicle according to the invention with an anti-noise system according to the invention;

Fig.2

a headrest of one in the interior of the vehicle figure 1 arranged vehicle seat having parts of the anti-noise system according to the invention in a schematic representation;

Fig.3

an inventive anti-sound system according to a preferred embodiment in a schematic representation;

Fig.4

an inventive anti-sound system according to a further preferred embodiment in a schematic representation.

figure 1 shows a section of an emergency vehicle 1 comprising a body 3 providing an interior space 2 and a continuous tone horn 4.

The subsequent tone horn 4 has a loudspeaker 5 for emitting siren-like signal tones.

In the interior 2 of the emergency vehicle 1, a microphone 6 and three surface speakers 7, 8, 9 are arranged. The position of the microphone 6 is only an example. The microphone 6 can also be arranged at any other desired position in the interior 2 . Microphone 6 and loudspeakers 7, 8, 9 are connected to one another via a computer unit (not shown). Furthermore, the computer unit can be connected to an amplifier, not shown.

The microphone 6 is used to record the sound waves emitted by the subsequent tone horn 4 . Using a computer unit and/or an amplifier, artificial sound signals are generated based on the recorded sound waves and emitted as counter-noise throughout the interior 2 via the loudspeakers 7, 8, 9. In this way, an almost complete compensation of the sound waves of the subsequent tone horn 4 is achieved in an advantageous manner.

In this case, the flat loudspeaker 7 is arranged on a surface of the windshield 10 on the interior side. The flat panel loudspeaker 8 is arranged on a body surface of the ceiling 11 on the interior side. The flat loudspeaker 9 is arranged on a body surface of the rear wall 12 on the interior side. In this way, an advantageous acoustic irradiation of the entire volume of the interior is achieved.

Also shown is a flat panel loudspeaker 13 which is arranged inside the housing 14 of the continuous tone horn 4 . If the emergency vehicle is also equipped with a visual warning signal system, as is the case here, the housing 14 is designed as a light bar. Within the meaning of the invention, this space enclosed by the housing or the light bar is also considered to be the “interior”. As a result, a more extensive compensation of the undesired sound waves is achieved in particular in the upper area of the interior 2 in that the reverberation is compensated directly at the generator.

Also shown is a vehicle seat 15 which in figure 2 is shown in detail.

figure 2 shows the headrest 16 of the vehicle seat 15 in three different views. The top view shows the headrest 16 from the outside looking from the front. The middle view shows a first common cross-sectional shape of a headrest 16, while the bottom view shows a second common cross-sectional shape of a headrest 16.

The headrest according to the middle view has two microphones 17, 18 and a pair of loudspeakers 19 in the present example. In contrast, the headrest 16 according to the bottom view has no microphones but only a pair of loudspeakers 20 . The individual loudspeakers of a loudspeaker pair 19, 20 are each arranged at opposite ends of the headrest 16. As a result, the speakers of the respective Loudspeaker pairs 19, 20 are arranged on either side of a user's ears when the headrest 16 is used as intended.

The cross section of the headrest 16 has, as shown by way of example in the middle view, a shape that is angled in sections. The angled configuration results in a substantially U-shaped cross-sectional section.

In contrast, the headrest 16 has an essentially straight or linear shape in cross section, as shown by way of example in the bottom view.

The microphones 17, 18, like the microphone 6, serve to record the sound waves of the subsequent tone horn 4. The pairs of loudspeakers 19, 20 serve to output counter-sound in a directed manner. The loudspeakers of the loudspeaker pair 19 face each other and are thus aimed directly at the user's ears. The pair of speakers 20 have their speakers oriented forward, also toward the user's ears.

As a result, the anti-noise can be aimed directly at the ears of the respective user. This further improves the compensation for the unwanted sound waves, particularly in combination with the flat-panel loudspeakers 7 , 8 , 9 .

The number of microphones and loudspeakers can vary in order to individually adapt the anti-noise system to the local conditions, the desired quality of the anti-noise and the justifiable complexity. In particular, the flat panel loudspeakers used can be replaced by conventional loudspeakers. Basically, a single loudspeaker is sufficient. Furthermore, should this be necessary, microphones can be completely dispensed with at the expense of the quality of the anti-noise. The anti-sound system can either have a central control in the form of a corresponding computer unit or have individual discrete and self-sufficient assemblies in which microphone, amplifier/computer unit and/or loudspeakers are combined.

the Figures 3 and 4 each show configurations of the anti-sound system according to the invention in the form of discrete assemblies 21, 22.

The two modules 21, 22 differ in the type of energy supply. Otherwise, the two assemblies 21, 22 essentially have the same structural design.

The assembly 21, 22 has a housing 23. A loudspeaker 24 and a microphone 25 are arranged in this housing 23, which are connected to one another via a unit 26 also arranged in the housing, in particular in the form of an amplifier and/or a computer unit, which can be designed as a simple controller.

The unit 26 of the assembly 21 can be connected to a power supply system, in particular the vehicle electrical system, for the purpose of supplying energy. The assembly provides a corresponding power connection 27 for this purpose

In contrast to this, the unit 26 of the assembly 22 is connected to an energy store 28 which is also arranged in the housing 23 for the purpose of supplying energy. In the present case, the energy store 28 can preferably be formed by an accumulator, in particular a lithium-ion accumulator.

Reference List

1

emergency vehicle

2

inner space

3

body

4

follow-up horn

5

speaker

6

microphone

7

flat panel speaker

8th

flat panel speaker

9

flat panel speaker

10

windscreen

11

ceiling

12

back panel

13

flat panel speaker

14

housing/lightbar

15

vehicle seat

16

headrest

17

microphone

18

microphone

19

speaker pair

20

speaker pair

21

module

22

module

23

casing

24

speaker

25

microphone

26

unit

27

power connection

28

energy storage

Claims (15)

Method for reducing noise pollution in the interiors of vehicles, in particular emergency vehicles, with a subsequent tone horn, in which a counter-noise corresponding to the sound waves of the subsequent tone horn is generated in the interior of the vehicle. Method according to Claim 1, characterized in that the sound waves of the continuous-tone horn are recorded by means of at least one microphone installed in the interior in order to generate the anti-noise. Method according to Claim 2, characterized in that the detected sound waves are converted into electronic signals, the electronic signals are modified, in particular phase-shifted and/or inverted, the modified electronic signals are reproduced via a loudspeaker installed in the interior as counter-sound to the sound waves of the subsequent tone horn are output and that the subsequent tone horn noise associated interference signals and / or harmonics are also detected and compensated by means of anti-noise. Method according to one of Claims 1 to 3, characterized in that sound waves in the frequency range from 300 Hz to 700 Hz, in particular 360 Hz to 630 Hz, are compensated for by means of the counter-sound. Anti-sound system for installation in vehicles, in particular emergency vehicles, with a continuous tone horn to reduce noise pollution inside the vehicle, at least having a loudspeaker that can be installed in the interior of the vehicle to generate a counter-noise corresponding to the sound waves of the subsequent tone horn. Anti-sound system according to Claim 5, characterized by at least one microphone which can be installed in the interior space for detecting the sound waves of the subsequent tone horn. Anti-sound system according to Claim 6, characterized by an amplifier and/or a computer unit for converting the detected sound waves into electronic signals and/or for modifying, in particular phase shifting and/or inverting, the detected sound waves or the electronic signals. Anti-sound system according to one of Claims 6 or 7, characterized in that the modified sound waves and/or the modified electronic signals can be output as anti-sound by means of the loudspeaker in the interior of the vehicle. Anti-sound system according to one of Claims 5 to 8, characterized in that the at least one loudspeaker is designed as a surface loudspeaker. Vehicle, in particular an emergency vehicle, with a continuous tone horn, having an anti-noise system arranged in the interior of the vehicle according to one of Claims 5 to 9. Vehicle according to Claim 10, characterized in that the at least one loudspeaker is designed as a surface loudspeaker which is installed on an interior surface of a window pane, in particular the windshield, and/or on an interior surface of the body/interior. Vehicle according to Claim 11, characterized by at least one non-surface loudspeaker which is installed in the upper part of a vehicle seat, in particular the headrest. Vehicle according to one of Claims 10 to 12, characterized in that the at least one loudspeaker is installed in the lightbar in order to compensate for the sound waves of the subsequent tone horn directly at the generator. Vehicle according to one of Claims 10 to 13, characterized in that the anti-sound system has individual assemblies, one assembly having a housing in which at least one microphone, a computer unit, in particular in the form of a microcontroller, an amplifier and a loudspeaker are arranged. Vehicle according to Claim 14, characterized in that at least one module for the power supply is connected to the on-board network of the vehicle and/or that at least one module for the self-sufficient power supply has an energy store, in particular in the form of a battery.

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