DE102020101100A1 - Method and device for operating a noise suppression system in a motor vehicle - Google Patents

Abstract

The invention relates to a method for noise reduction of ambient noises in a vehicle interior, with the following steps: - Detecting a sound signal of a sound-transmitting surface of a vehicle part, which corresponds to a vibration corresponding to ambient noise; - Modifying the sound signal by eliminating or reducing the strength of a signal component with one or more predetermined frequencies, the predetermined frequencies depending on the frequencies of one or more acoustic warning signals; - generating a counter-sound signal from the modified sound signal; - applying the counter-sound signal to a sound transducer coupled to the sound-transmitting surface.

Description

Technical area

The invention relates to motor vehicles, and in particular to measures for reducing ambient noise in a vehicle interior.

Technical background

During the operation of the motor vehicle, vehicle occupants are usually permanently exposed to ambient noises which, due to their high sound level, can represent a high level of exposure. This can impair the driver's concentration on the traffic situation and thus endanger driving safety.

To reduce the volume of ambient noises in the vehicle interior, the use of insulating materials between the body and the interior trim is provided as passive measures. However, since a large proportion of the ambient noise is transmitted via the vehicle windows, the provision of passive insulation is generally not sufficient. Various active soundproofing systems are provided for use in a motor vehicle in order to dampen ambient noises by stimulating surfaces with an out-of-phase oscillation.

For example, describes the U.S. 5,812,684 A the use of a vehicle side window for active noise reduction. The disk is excited to vibrate by means of actuators.

The pamphlet DE 101 16 166 A1 discloses an active multilayer pane arrangement for a side window of a vehicle, an inner pane of a multilayer pane arrangement being caused to vibrate with the aid of actuators.

From the pamphlet EP 0 964 387 A2 a method for influencing noise originating from window panes, preferably a background noise that can be perceived in a passenger compartment, is known, a piezo element being arranged in the area of the transition between window frame and window pane, with the piezo element taking over the entire energy and / or the composition of the frequencies of the is changed via the window frame and / or via the window pane transmitted vibrations.

Furthermore, from the publication EP 3 486 897 A1 a work vehicle with a closed cabin interior is known, which is enclosed by at least one pane, which is provided with an actuator device, a sensor device and a control unit connected to the sensor device and the actuator device. The actuator device for noise reduction in the cabin interior is controlled as a function of signals from the sensor device. The actuator device has an inertial vibration exciter fastened to the inner surface of the window, the inertial vibration exciter being controlled with an adaptive and predictive control for dependence on microphone signals in order to carry out an active noise reduction in the cabin interior.

However, the active noise reduction in the vehicle interior can lead to important ambient noises, such as a vehicle horn, a siren or the like, not being perceived by a driver of the motor vehicle, since these are greatly attenuated together with the other ambient noises.

It is therefore the object of the present invention to ensure that important ambient noises remain perceptible in the vehicle interior, while the remaining ambient noises are attenuated.

Disclosure of the invention

This object is achieved by the method for reducing ambient noise in a vehicle interior according to claim 1 and by the device and the motor vehicle according to the independent claims.

Further refinements are given in the dependent claims.

• - Erfassen eines Schallsignals einer schallübertragenden Fläche eines Fahrzeugteils, das eine Schwingung entsprechend Umgebungsgeräuschen aufweist;
• - Modifizieren des Schallsignals durch Eliminieren oder Reduzieren der Stärke eines Signalanteils mit einer oder mehrerer vorgegebenen Frequenzen, wobei die vorgegebenen Frequenzen von den Frequenzen eines oder mehrerer akustischer Warnsignale abhängen;
• - Erzeugen eines Gegenschallsignals aus dem modifizierten Schallsignal;
• - Beaufschlagen eines mit der schallübertragenden Fläche gekoppelten Schallwandlers mit dem Gegenschallsignal.

According to a first aspect, a method for reducing ambient noise in a vehicle interior is provided, comprising the following steps:

• - Detecting a sound signal of a sound-transmitting surface of a vehicle part, which has a vibration corresponding to ambient noise;
• Modifying the sound signal by eliminating or reducing the strength of a signal component with one or more predetermined frequencies, the predetermined frequencies depending on the frequencies of one or more acoustic warning signals;
• - Generating a counter-sound signal from the modified sound signal;
• - Applying the counter-sound signal to a sound transducer coupled to the sound-transmitting surface.

The above method suggests reducing the perception of ambient noise in a vehicle interior by counter-noise, in particular by applying a counter-vibration to a sound-transmitting surface of the motor vehicle, for example a window pane, using a sound transducer. For this purpose, an oscillation or vibration of the sound-transmitting surface is recorded and a corresponding counter-oscillation is coupled in.

In order to ensure that ambient noises that are important for the driver, such as a police siren, siren, fire brigade siren, horns from motor vehicles, reversing signals from commercial vehicles, bicycle bells and the like, can continue to be perceived by the driver in the vehicle interior, the noise reduction in the interior takes place selectively. Thus, by appropriately activating the sound transducer by a control unit, known frequencies or frequency ranges of ambient noises that cannot be attenuated or only to a lesser extent can be provided.

In the case of a sound pattern, this can be recorded and interpreted with the aid of a sound pattern recognition unit. The sound pattern recognition unit can be designed to do this, for example, by Fourier transformation of recorded sound signals into a frequency range and by evaluation of the Fourier transformed sound signals known per se with respect to known sound patterns. This results in frequency ranges that are not to be attenuated, in particular temporal progressions of frequency ranges that are not to be attenuated, which are to be excluded from the noise reduction in the interior.

The frequency ranges not to be attenuated can thus be adapted to the sound pattern. For example, a sirloin has a time sequence of different frequencies that correspond to a known pattern. By recognizing this time sequence, the filtering of the corresponding frequencies can be suppressed accordingly.

Furthermore, the sound signal can be detected by the sound transducer to which the counter-sound signal is applied, or a microphone for recording ambient noise.

According to one embodiment, the sound signal can be modified by transforming it into a frequency range and then reducing or eliminating the signal components of the one or more predetermined frequencies.

It can be provided that the counter-sound signal is generated by providing signal components of the frequency components remaining in the modified sound signal in antiphase.

Furthermore, the predetermined frequencies can correspond to the frequencies of the one or more acoustic warning signals and in particular include a frequency range around the frequency (s) of the one or more acoustic warning signals.

• - Erfassen eines Schallsignals von einer schallübertragenden Fläche eines Fahrzeugteils, das eine Schwingung entsprechend Umgebungsgeräuschen aufweist;
• - Modifizieren des Schallsignals durch Eliminieren oder Reduzieren der Stärke eines Signalanteils mit einer oder mehrerer vorgegeben Frequenzen, wobei die vorgegebenen Frequenzen von den Frequenzen eines oder mehrerer akustischer Warnsignale abhängen;
• - Erzeugen eines Gegenschallsignals aus dem modifizierten Schallsignal;
• - Beaufschlagen eines mit der schallübertragenden Fläche gekoppelten Schallwandlers mit dem Gegenschallsignal.

According to a further aspect, a device, in particular a control unit, is provided for reducing ambient noise in a vehicle interior, the device being designed to:

• - Detecting a sound signal from a sound-transmitting surface of a vehicle part, which has a vibration corresponding to ambient noise;
• Modifying the sound signal by eliminating or reducing the strength of a signal component with one or more predetermined frequencies, the predetermined frequencies depending on the frequencies of one or more acoustic warning signals;
• - Generating a counter-sound signal from the modified sound signal;
• - Applying the counter-sound signal to a sound transducer coupled to the sound-transmitting surface.

• - einen Schallwandler, der mit einer schallübertragenden Fläche gekoppelt ist; und
• - die obige Vorrichtung.

According to a further aspect, a motor vehicle is provided comprising:

• - A sound transducer which is coupled to a sound-transmitting surface; and
• - the above device.

Figure list

• 1 eine schematische Darstellung einer Fahrzeugtür mit einer Seitenscheibe, die mit einem System zur Geräuschreduzierung im Fahrzeuginnenraum versehen ist; und
• 2 ein Flussdiagramm zur Veranschaulichung eines Verfahrens zum Betreiben des Geräuschminderungssystems der 1.

Embodiments are explained in more detail below with reference to the accompanying drawings. Show it:

• 1 a schematic representation of a vehicle door with a side window, which is provided with a system for noise reduction in the vehicle interior; and
• 2 FIG. 3 is a flow chart illustrating a method for operating the noise reduction system of FIG 1 .

Description of embodiments

1 shows an example of a noise reduction system 1 for a vehicle door 2 one Motor vehicle. The vehicle door 2 has a side window 3 on. The side window 3 represents a sound-transmitting surface between the vehicle environment and the vehicle interior. Ambient noises lead to corresponding vibrations of the side window 3 , which is emitted as sound into the vehicle interior, so that the ambient noise can be perceived in the vehicle interior.

The side window 3 is with a transducer 4th provided, which represents an electromechanical converter and is electrically controllable. The transducer 4th can for example on an area of the side window 3 located in the driver's door 2 located so that the transducer 4th is not visible from the outside. The transducer is like this on the side window 3 arranged that this vibrates according to an electrical control signal on the side window 3 can muster.

Furthermore, the sound transducer 4th be formed, a vibration of the side window 4th to detect and provide an electrical sound signal.

In particular, the sound transducer 4th have a piezo element or an electromagnetic transducer. Although the transducer 4th usually also for sound detection or vibration detection on the side window 3 can be used, a microphone can additionally or alternatively be used 6th be provided, which is arranged on the motor vehicle to detect ambient noise. A further sound transducer on the side window can also be used for sound detection or vibration detection 3 be provided.

The transducer 4th is made using a control unit 5 controlled. The control unit 5 is designed, the ambient noise as an ambient noise signal from the sound transducer 4th or from the microphone 6th and a frequency-wise anti-phase oscillation on the transducer 4th to apply, so that the vibrations of the side window caused by the ambient noise 3 be damped or compensated. This means that no sound is emitted from the side window 3 into the vehicle interior, which significantly reduces the perception of ambient noise.

Since the vehicle windows represent a direct sound-transmitting surface of ambient sound into the vehicle interior, a large part of the ambient noise perceived in the vehicle interior is transmitted via the vehicle windows. If the noise transmission via the vehicle windows is attenuated, a large proportion of the ambient noise perceptible in the vehicle interior can accordingly be suppressed. The concept of noise reduction through counter-noise is well known and accordingly will not be discussed in detail.

However, some of the ambient noise represents valuable information for the driver of a motor vehicle and should, if possible, not be dampened or suppressed to such an extent that the driver can no longer perceive it. These include, for example, police and fire brigade sirens, vehicle horns from other road users, bicycle bells, the reversing signal from commercial vehicles and the like. However, these warning signals are well defined and have known frequencies and frequency patterns that move in specific frequency ranges. For example, a police siren has a tone signal with two intermittently successive predetermined frequencies.

It is therefore provided that the generation of counter-sound is suppressed for the frequencies of such warning signals, so that these warning signals can continue to be perceived by the driver in the vehicle interior, while the other frequencies continue to be attenuated by generating counter-sound. In particular, the frequencies that are not to be suppressed can be determined by specifying frequency ranges in order to take into account the effect of Doppler effects in the case of sound sources moving relative to the own vehicle.

The active noise cancellation method used in the noise cancellation system 1 can be executed in the control unit 5 be implemented as software and / or as hardware. In the control unit 5 the procedure described below is carried out.

In step S1, the control unit 5 Sound signals captured by the side window 3 be released into the vehicle interior. This can be done by the vibration of the side window 3 using the transducer 4th (or the other sound transducer) can be detected or it can be on the side window 3 ambient noise using the microphone 6th captured on the side window 3 act and stimulate them to vibrate.

In step S2, the sound signals are analyzed and, for example, broken down into frequency components with the aid of a Fourier transformation.

In step S3 those signal components are now eliminated from the sound signal transformed into the frequency range, the frequencies of which are one or more frequencies of a warning signal that can occur in the vehicle environment. These are, for example, 362-483 Hz or 410 - 547 Hz for Martin's horns. These frequencies are predefined. The frequencies to be filtered are preferably extended to frequency ranges by the corresponding frequencies of the warning signals in order to take into account the influences of Doppler effects.

The frequency spectrum modified in this way then becomes a control signal for the sound transducer in step S4 4th converted, which corresponds to a counter-sound signal. The modified frequency components are each adapted in time to the oscillation of the respective frequency component of the recorded sound signal in such a way that one corresponds to the current vibration of the side window 3 180 ° phase-shifted, ie anti-phase oscillation due to the sound transducer 4th is produced. The sound transducer is activated by the counter-sound signal in step S5 4th applied.

This will cause the vibration of the side window 3 for frequency ranges that cannot be assigned to a frequency of a warning signal, attenuated, and the frequency components assigned to the warning signals are accordingly left essentially unaffected. When the sound transducer is applied, the side window vibrates 3 reduced for the frequencies that do not belong to traffic-relevant warning signals.

List of reference symbols

1

Noise reduction system

2

Vehicle door

3

Side window

4th

Transducer

5

Control unit

6th

microphone

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• US 5812684 A [0004]
• DE 10116166 A1 [0005]
• EP 0964387 A2 [0006]
• EP 3486897 A1 [0007]

Claims (7)

Method for reducing ambient noise in a vehicle interior, with the following steps: - Detection (S1) of a sound signal of a sound-transmitting surface (3) of a vehicle part (2), which corresponds to an oscillation corresponding to ambient noise; - Modifying (S2) the sound signal by eliminating or reducing the strength of a signal component with one or more predetermined frequencies, the predetermined frequencies depending on the frequencies of one or more acoustic warning signals; - Generating a counter-sound signal from the modified sound signal; - Applying (S4) a sound transducer (4) coupled to the sound-transmitting surface (3) with the counter-sound signal. Procedure according to Claim 1 , wherein the sound signal is detected by the sound transducer (4) to which the counter-sound signal is applied, or a microphone (6) for recording ambient noise. Procedure according to Claim 1 or 2 , wherein the sound signal is modified by transforming it into a frequency range and then reducing or eliminating the signal components of the one or more predetermined frequencies. Method according to one of the Claims 1 until 3 , wherein the counter-sound signal is generated by providing signal components of the frequency components remaining in the modified sound signal in antiphase. Method according to one of the Claims 1 until 4th , wherein the predetermined frequencies correspond to the frequencies of the one or more acoustic warning signals and in particular comprise a frequency range around the frequency (s) of the one or more acoustic warning signals. Device, in particular control unit (5), for reducing ambient noise in a vehicle interior, the device being designed to: - Detection of a sound signal of a sound-transmitting surface (3) of a vehicle part (2), which corresponds to an oscillation corresponding to ambient noise; Modifying the sound signal by eliminating or reducing the strength of a signal component with one or more predetermined frequencies, the predetermined frequencies depending on the frequencies of one or more acoustic warning signals; - Generating a counter-sound signal from the modified sound signal; - Applying the counter-sound signal to a sound transducer (4) coupled to the sound-transmitting surface. Motor vehicle comprising: - a sound-transmitting surface, in particular a front window or a side window, - a sound transducer (4) which is coupled to the sound-transmitting surface; - a device according to Claim 6 .

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