EP0805431B1 - Method and device for active noise control of gas flows - Google Patents

Method and device for active noise control of gas flows Download PDF

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Publication number
EP0805431B1
EP0805431B1 EP97102834A EP97102834A EP0805431B1 EP 0805431 B1 EP0805431 B1 EP 0805431B1 EP 97102834 A EP97102834 A EP 97102834A EP 97102834 A EP97102834 A EP 97102834A EP 0805431 B1 EP0805431 B1 EP 0805431B1
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EP
European Patent Office
Prior art keywords
volume flow
lines
volume
noise reduction
taken
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EP97102834A
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German (de)
French (fr)
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EP0805431A2 (en
EP0805431A3 (en
Inventor
Ingo Dr. Borchers
Ludwig Dipl.-Ing. Schauwecker
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Dornier GmbH
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Dornier GmbH
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    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
    • G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
    • G10K11/1785—Methods, e.g. algorithms; Devices
    • G10K11/17857—Geometric disposition, e.g. placement of microphones
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
    • G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
    • G10K11/1787—General system configurations
    • G10K11/17873—General system configurations using a reference signal without an error signal, e.g. pure feedforward
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
    • G10K11/178—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound by electro-acoustically regenerating the original acoustic waves in anti-phase
    • G10K11/1787—General system configurations
    • G10K11/17875—General system configurations using an error signal without a reference signal, e.g. pure feedback
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/10—Applications
    • G10K2210/101—One dimensional
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/10—Applications
    • G10K2210/112—Ducts
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/10—Applications
    • G10K2210/128—Vehicles
    • G10K2210/1282—Automobiles
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/10—Applications
    • G10K2210/128—Vehicles
    • G10K2210/1282—Automobiles
    • G10K2210/12822—Exhaust pipes or mufflers
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/30—Means
    • G10K2210/321—Physical
    • G10K2210/3212—Actuator details, e.g. composition or microstructure
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K2210/00—Details of active noise control [ANC] covered by G10K11/178 but not provided for in any of its subgroups
    • G10K2210/30—Means
    • G10K2210/321—Physical
    • G10K2210/3212—Actuator details, e.g. composition or microstructure
    • G10K2210/32121—Fluid amplifiers, e.g. modulated gas flow speaker using electrovalves

Definitions

  • the invention relates to a method and a device for sound reduction according to the preamble of claims 1 and 11.
  • DE 43 41 951 A1 discloses a method for active noise reduction for the exhaust system of a motor vehicle, in which two volume flows are superimposed.
  • the path length of at least one of the two volume flows is changed as a function of the operating temperature in order to obtain an optimal phase shift of the two volume flows with regard to the sound attenuation.
  • the change in the path length of the volume flow is achieved by a variable-length pipe.
  • the area which the tube occupies at maximum deflection must therefore be kept clear at all times, so that there is a large space requirement for the device.
  • the object of the invention is therefore to provide a method and apparatus for to create active noise reduction with the smallest possible size.
  • a first and a second volume flow are present, one of which flows through Modulation with a predetermined frequency spectrum is changed in such a way that in the subsequent interference of the two volume flows, the sound reduction is effected.
  • the modulation creates in the modulated Volume flow is a sound spectrum that is associated with the subsequent interference with the other volume flow an optimal extinction over a large Frequency range enabled.
  • active silencers can be used a volume of less than one liter can be realized.
  • the invention is therefore particularly suitable for use in motor vehicles.
  • the method according to the invention enables cancellation over a large sound spectrum.
  • the process can also be done entirely generally used to generate a predetermined sound spectrum be (sound design).
  • one of the two volume flows are taken from the other volume flow. That means, that a volume flow, which is afflicted with the sound to be reduced, in two partial volume flows is divided, the two partial volume flows after appropriate modulation of one of the two sub-currents for interference to be brought.
  • the one with the volume flow to be reduced with a second, from first volume flow independent volume flow are superimposed on the is present on the unit in question anyway (e.g. wind, vehicle, Compressed air, exhaust gas jet).
  • Fig. 1 shows the first method alternative of the invention in a schematic Presentation.
  • the line 1 is shown with the first volume flow 10, whose sound is to be reduced.
  • a second Line 2 which is part of the first volume flow, now as a second volume flow Designated 20, leads to an actuator A, in which it is in phase is modulated with a predetermined frequency spectrum.
  • the modulation takes place in such a way that in the subsequent interference of the first and second Volume flow 10.20 the highest possible noise reduction over the entire Sound spectrum is reached (appropriate phase difference between first and second volume flow, in particular 180 °).
  • the spectrum the sound waves to be amortized in the first volume flow 10 is reduced by one sensor not shown here, e.g. a microphone detects a reference signal for sound cancellation.
  • the reference signal is known in Prepared and used to control actuator A.
  • This method can e.g. for reducing noise in the exhaust gas jet of internal combustion engines are used, especially in motor vehicles.
  • the use for noise reduction in a compressed air stream is also advantageous a compressed air compressor.
  • Reduction is another area of application for the specified method the driving noise in vehicles, especially rail vehicles.
  • the airstream In ICE trains, the airstream generates particularly on the pantographs strong noises. This can be remedied if part of the Driving wind is modulated in an actuator and then with the noise-generating airstream is superimposed. Different from that in FIG. 1 shown case, however, line 1 is omitted here, since the airstream is natural is not wired.
  • Fig. 2 shows the second method alternative of the invention in a schematic Presentation.
  • One recognizes the line 1 with the first volume flow 10, whose sound is to be reduced.
  • line 1 is one of line 1, which is independent of line 1, is available for second volume flow 20, which is connected to the input of the actuator A.
  • This second Line 2 is fed by a volume flow that is independent of the Noise reduction on the vehicle or unit in question is available.
  • a specific embodiment of the invention as a silencer for an internal combustion engine 3 shows the exhaust gas jet of an internal combustion engine is after flowing through a conventional pre-muffler 50 in one Pre-chamber 40 divided and then in the form of two coaxial flows 10.20 fed to the actuator A.
  • the central part of the exhaust jet (first volume flow 10) flows through the actuator A largely undisturbed, the ring-shaped outer exhaust gas jet (second volume flow 20) is through a valve modulated with a predetermined frequency spectrum (Fig. 4) and interferes at the outlet of the actuator A with the central beam 10.
  • the actuator A is from Sensors, here microphones (Fig. 4) controlled, which the sound frequency spectrum to be canceled and possibly record the remaining sound.
  • the Microphone signals are processed and used in a manner known per se as input signals for the modulation in the actuator. Because the two gas flows 10.20 approximately the same temperature (influence on the speed of sound) and the sound sources have almost the same position, leads to the superposition of the Sound waves for optimal, largely directionally insensitive extinction the unwanted noise.
  • the lines 1, 2 can be used to improve the directional characteristic also be arranged in such a way that they continue to be run parallel, but their axes no longer coincide.
  • the two streams can also coexist and e.g. run in parallel.
  • the actuator can also use bleed air from an existing turbocharger be supplied.
  • Fig. 4 shows the sectional drawing of an advantageous embodiment of an inventive Device such as e.g. used in the device of FIG. 3 can be.
  • the central line 1 here: exhaust pipe for the exhaust jet an internal combustion engine
  • an electro-pneumatic actuator A with inputs and outputs for the second Volume flow 20 placed.
  • the second volume flow 20 in line 2 can be taken both from line 1 for the first volume flow 10 be, as well as from another, existing on the vehicle or unit Volume flow can be removed.
  • the sound waves to be repaid are detected via one or more microphones M in line 1.
  • three powerful, axially magnetized are on the exhaust pipe 1 Threaded ring magnets 60.
  • the two outer faces of the permanent magnets 60 form a north pole and a south pole.
  • the magnets 60 sit in a pot-shaped housing 62 made of cast iron, which together with the pole shoe 64 at the other end is almost closed Magnetic circuit forms.
  • cylindrical coil valve ring vibrates in the housing 62 66 with a drive signal derived from the output signal of the Microphone M is applied.
  • the coil 66 is on several springs (leaf springs 67) hung up.
  • the gas stream 20 to be modulated is through openings in the bottom of the housing around the magnets 60 into a prechamber 68 and then through an annular one Gap, the width of which corresponds to the oscillating coil 66 the selected control signal is varied, led to the exit.
  • antechamber 68, gap and outlet opening are from the outlet-side cover 65, the is screwed in front of the cup-shaped housing 62, limited.
  • the exit side The area of the secondary gas line 2 is designed as a sound funnel.
  • an actuator can be used with the actuator described selectable sound frequency spectrum generated in the first volume flow 10 become.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Exhaust Silencers (AREA)
  • Soundproofing, Sound Blocking, And Sound Damping (AREA)
  • Separation Of Gases By Adsorption (AREA)

Description

Die Erfindung betrifft ein Verfahren sowie eine Vorrichtung zur Schallreduzierung nach dem Oberbegriff der Patentansprüche 1 bzw. 11.The invention relates to a method and a device for sound reduction according to the preamble of claims 1 and 11.

Es ist allgemein bekannt, daß Schallwellen durch Interferenz mit gegenphasig schwingenden Schallwellen ausgelöscht werden können. Weiterhin ist bekannt, daß Schallwellen durch die Modulation eines Gasstromes erzeugt werden können.It is common knowledge that sound waves are caused by interference with out of phase vibrating sound waves can be extinguished. Farther it is known that sound waves by modulating a gas stream can be generated.

Bekannte aktive Schalldämpfer benötigen ein relativ großes Volumen, das den nutzbaren Raum an einer Vorrichtung, an der Schall reduziert werden soll, einschränkt. Dies ist insbesondere bei Personenkraftwagen oder Krafträdern problematisch. Aus der DE 43 41 951 A1 ist z.B. ein Verfahren zur aktiven Schallreduzierung für die Abgasanlage eines Kraftfahrzeugs bekannt, bei dem zwei Volumenströme überlagert werden. Dabei wird die Weglänge zumindest eines der beiden Volumenströme in Abhängigkeit von der Betriebstemperatur verändert, um eine optimale Phasenverschiebung der beiden Volumenströme im Hinblick auf die Schalldämpfung zu erhalten. Die Änderung der Weglänge des Volumenstroms wird durch ein längenveränderliches Rohr erreicht. Der Bereich, den das Rohr bei maximaler Auslenkung einnimmt, muß somit ständig freigehalten werden, so daß sich ein großer Raumbedarf für die Vorrichtung ergibt.Known active silencers require a relatively large volume, which limits the usable space on a device on which noise is to be reduced. This is particularly problematic with passenger cars or motorcycles. DE 43 41 951 A1 , for example, discloses a method for active noise reduction for the exhaust system of a motor vehicle, in which two volume flows are superimposed. The path length of at least one of the two volume flows is changed as a function of the operating temperature in order to obtain an optimal phase shift of the two volume flows with regard to the sound attenuation. The change in the path length of the volume flow is achieved by a variable-length pipe. The area which the tube occupies at maximum deflection must therefore be kept clear at all times, so that there is a large space requirement for the device.

Aufgabe der Erfindung ist es deshalb, ein Verfahren und Vorrichtung zur aktiven Schallreduzierung mit einer möglichst kleinen Baugröße zu schaffen.The object of the invention is therefore to provide a method and apparatus for to create active noise reduction with the smallest possible size.

Diese Aufgabe wird mit einem Verfahren nach Anspruch 1 sowie einer Vorrichtung nach Anspruch 11 gelöst. Vorteilhafte Ausbildungen sind Gegenstände weiterer Ansprüche.This object is achieved with a method according to claim 1 and a device solved according to claim 11. Advantageous training courses are objects further claims.

Bei dem erfindungsgemäßen Verfahren zur aktiven Schallreduzierung sind ein erster und ein zweiter Volumenstrom vorhanden, von denen einer durch Modulation mit einem vorgegebenen Frequenzspektrum derart verändert wird, daß bei der nachfolgenden Interferenz der beiden Volumenströme die Schallreduzierung bewirkt wird. Durch die Modulation entsteht in dem modulierten Volumenstrom ein Schallspektrum, das bei der nachfolgenden Interferenz mit dem anderen Volumenstrom eine optimale Auslöschung über einen großen Frequenzbereich ermöglicht.In the inventive method for active noise reduction a first and a second volume flow are present, one of which flows through Modulation with a predetermined frequency spectrum is changed in such a way that in the subsequent interference of the two volume flows, the sound reduction is effected. The modulation creates in the modulated Volume flow is a sound spectrum that is associated with the subsequent interference with the other volume flow an optimal extinction over a large Frequency range enabled.

Mit dem erfindungsgemäßen Verfahren können aktive Schalldämpfer mit einem Volumen von weniger als einem Liter realisiert werden. Die Erfindung eignet sich deshalb ganz besonders für den Einsatz in Kraftfahrzeugen.With the method according to the invention, active silencers can be used a volume of less than one liter can be realized. The invention is therefore particularly suitable for use in motor vehicles.

Anders als bei der bereits erwähnten DE 43 41 951 A1, bei der nur eine bestimmte Schallfrequenz optimal ausgelöscht werden kann, ist mit dem erfindungsgemäßen Verfahren die Auslöschung über ein großes Schallspektrum möglich.In contrast to the already mentioned DE 43 41 951 A1, in which only a certain sound frequency can be optimally canceled out, the method according to the invention enables cancellation over a large sound spectrum.

Unabhängig von einer Schallreduzierung kann das Verfahren auch ganz allgemein zur Erzeugung eines vorbestimmten Schallspektrums verwendet werden (Sounddesign).Regardless of a sound reduction, the process can also be done entirely generally used to generate a predetermined sound spectrum be (sound design).

In einer vorteilhaften Ausführung der Erfindung kann einer der beiden Volumenströme dem anderen Volumenstrom entnommen werden. Das bedeutet, daß ein Volumenstrom, der mit dem zu reduzierenden Schall behaftet ist, in zwei Teilvolumenströme aufgeteilt wird, wobei die beiden Teilvolumenströme nach einer entsprechenden Modulation eines der beiden Teilströme zur Interferenz gebracht werden.In an advantageous embodiment of the invention, one of the two volume flows are taken from the other volume flow. That means, that a volume flow, which is afflicted with the sound to be reduced, in two partial volume flows is divided, the two partial volume flows after appropriate modulation of one of the two sub-currents for interference to be brought.

Alternativ zu dieser Aufteilung in zwei Teilvolumenströme kann der mit dem zu reduzierenden Schall behaftete Volumenstrom mit einem zweiten, vom ersten Volumenstrom unabhängigen Volumenstrom überlagert werden, der an dem betreffenden Aggregat sowieso vorhanden ist (z.B. Fahrtwind, Fahrzeug, Druckluft, Abgasstrahl).As an alternative to this division into two partial volume flows, the one with the volume flow to be reduced with a second, from first volume flow independent volume flow are superimposed on the is present on the unit in question anyway (e.g. wind, vehicle, Compressed air, exhaust gas jet).

In beiden Fällen kann somit bezüglich des für die Interferenz benötigten zweiten Volumenstroms auf einen bereits vorhandenen Volumenstrom zurückgegriffen werden. Ein eigens für diesen Zweck vorgesehenen Volumenstrom ist somit nicht notwendig.In both cases, the second required for the interference can thus Volume flow to fall back on an already existing volume flow become. A volume flow specially provided for this purpose is therefore not necessary.

Die Erfindung wird beispielhaft anhand der Fig. 1 bis 4 näher erläutert. Es zeigen:

Fig. 1
die erste Verfahrensvariante des erfindungsgemäßen Verfahrens
Fig. 2
die zweite Verfahrensvariante des erfindungsgemäßen Verfahrens
Fig. 3
eine Ausführung der erfindungsgemäßen Vorrichtung als Schalldämpfer für einen Verbrennungsmotor
Fig. 4
eine weitere Ausführung der erfindungsgemäßen Vorrichtung.
The invention is explained in more detail by way of example with reference to FIGS. 1 to 4. Show it:
Fig. 1
the first method variant of the method according to the invention
Fig. 2
the second method variant of the method according to the invention
Fig. 3
an embodiment of the device according to the invention as a silencer for an internal combustion engine
Fig. 4
a further embodiment of the device according to the invention.

Fig. 1 zeigt die erste Verfahrensalternative der Erfindung in schematischer Darstellung. Dargestellt ist die Leitung 1 mit dem ersten Volumenstrom 10, dessen Schall reduziert werden soll. Von dieser Leitung 1 zweigt eine zweite Leitung 2 ab, die einen Teil des ersten Volumenstroms, nun als zweiten Volumenstrom 20 bezeichnet, zu einem Aktuator A führt, in dem er phasengerecht mit einem vorgegebenen Frequenzspektrum moduliert wird. Die Modulation erfolgt derart, daß bei der anschließenden Interferenz von erstem und zweitem Volumenstrom 10,20 eine möglichst hohe Schallreduzierung über das gesamte Schallspektrum erreicht wird (zweckmäßigen Phasendifferenz zwischen erstem und zweiten Volumenstrom insbesondere 180°). Das Spektrum der zu tilgenden Schallwellen in dem ersten Volumenstrom 10 wird von einem hier nicht dargestellten Sensor, z.B. einem Mikrophon erfaßt, der ein Referenzsignal für die Schallauslöschung liefert. Das Referenzsignal wird in bekannter Weise aufbereitet und dient zur Ansteuerung des Aktuators A.Fig. 1 shows the first method alternative of the invention in a schematic Presentation. The line 1 is shown with the first volume flow 10, whose sound is to be reduced. From this line 1 branches a second Line 2, which is part of the first volume flow, now as a second volume flow Designated 20, leads to an actuator A, in which it is in phase is modulated with a predetermined frequency spectrum. The modulation takes place in such a way that in the subsequent interference of the first and second Volume flow 10.20 the highest possible noise reduction over the entire Sound spectrum is reached (appropriate phase difference between first and second volume flow, in particular 180 °). The spectrum the sound waves to be amortized in the first volume flow 10 is reduced by one sensor not shown here, e.g. a microphone detects a reference signal for sound cancellation. The reference signal is known in Prepared and used to control actuator A.

Dieses Verfahren kann z.B. zur Schallreduzierung im Abgasstrahl von Verbrennungsmotoren eingesetzt werden, insbesondere in Kraftfahrzeugen. Vorteilhaft ist auch der Einsatz zur Schallreduzierung in einem Druckluftstrom eines Druckluftverdichters.This method can e.g. for reducing noise in the exhaust gas jet of internal combustion engines are used, especially in motor vehicles. The use for noise reduction in a compressed air stream is also advantageous a compressed air compressor.

Ein weiteres Einsatzfeld für das angegebene Verfahren stellt die Reduzierung der Fahrtgeräusche bei Fahrzeugen, insbesondere Schienenfahrzeugen dar. Reduction is another area of application for the specified method the driving noise in vehicles, especially rail vehicles.

In ICE-Zügen erzeugt der Fahrtwind insbesondere an den Stromabnehmern starke Geräusche. Abhilfe kann hier geschaffen werden, wenn ein Teil des Fahrtwindes in einem Aktuator moduliert wird und anschließend mit dem geräuscherzeugenden Fahrtwind überlagert wird. Anders als in dem in Fig. 1 dargestellten Fall entfällt jedoch hier die Leitung 1, da der Fahrtwind naturgemäß nicht leitungsgebunden ist.In ICE trains, the airstream generates particularly on the pantographs strong noises. This can be remedied if part of the Driving wind is modulated in an actuator and then with the noise-generating airstream is superimposed. Different from that in FIG. 1 shown case, however, line 1 is omitted here, since the airstream is natural is not wired.

Fig. 2 zeigt die zweite Verfahrensalternative der Erfindung in schematischer Darstellung. Man erkennt die Leitung 1 mit dem ersten Volumenstrom 10, dessen Schall reduziert werden soll. Anders als in Fig. 1 ist hier eine von der Leitung 1 unabhängige Leitung 2 für den zweiten Volumenstrom 20 vorhanden, die mit dem Eingang des Aktuators A verbunden ist. Diese zweite Leitung 2 wird von einem Volumenstrom gespeist, der unabhängig von der Schallreduzierung an dem betreffenden Fahrzeug oder Aggregat bereits vorhanden ist. Vorteilhaft kann diese Verfahrensvariante für den Abgasstrom (= erster Volumenstrom) eines Verbrennungsmotors in einem Kraftfahrzeug verwendet werden, wobei der zweite Volumenstrom z.B. einem vorhandenen Turbolader als Zapfluft entnommen wird.Fig. 2 shows the second method alternative of the invention in a schematic Presentation. One recognizes the line 1 with the first volume flow 10, whose sound is to be reduced. Unlike in Fig. 1, here is one of line 1, which is independent of line 1, is available for second volume flow 20, which is connected to the input of the actuator A. This second Line 2 is fed by a volume flow that is independent of the Noise reduction on the vehicle or unit in question is available. This process variant can advantageously be used for the exhaust gas flow (= first volume flow) an internal combustion engine used in a motor vehicle the second volume flow e.g. an existing turbocharger is taken as bleed air.

Eine konkrete Ausbildung der Erfindung als Schalldämpfer für einen Verbrennungsmotor zeigt Fig. 3. Der Abgasstrahl eines Verbrennungsmotors wird nach Durchströmen eines herkömmlichen Vorschalldämpfers 50 in einer Vorkammer 40 aufgeteilt und dann in Form von zwei koaxialen Strömen 10,20 dem Aktuator A zugeführt. Der zentrale Teil des Abgasstrahles (erster Volumenstrom 10) durchströmt den Aktuator A weitgehend ungestört, der ringförmige äußere Abgasstrahl (zweiter Volumenstrom 20) wird durch ein Ventil mit einem vorgegebenen Frequenzspektrum moduliert (Fig. 4) und interferiert am Austritt des Aktuators A mit dem Zentralstrahl 10. Der Aktuator A wird von Sensoren, hier Mikrofonen (Fig. 4) angesteuert, die das zu tilgende Schallfrequenzspektrum und eventuell den übrigbleibenden Restschall erfassen. Die Mikrofonsignale werden in an sich bekannter Weise aufbereitet und dienen als Eingangssignale für die Modulation im Aktuator. Da die beiden Gasströme 10,20 etwa gleiche Temperaturen (Einfluß auf die Schallgeschwindigkeit) und die Schallquellen fast die gleiche Position haben, führt die Überlagerung der Schallwellen zu einer optimalen, weitgehend richtungsunempfindlichen Auslöschung der unerwünschten Geräusche.A specific embodiment of the invention as a silencer for an internal combustion engine 3 shows the exhaust gas jet of an internal combustion engine is after flowing through a conventional pre-muffler 50 in one Pre-chamber 40 divided and then in the form of two coaxial flows 10.20 fed to the actuator A. The central part of the exhaust jet (first volume flow 10) flows through the actuator A largely undisturbed, the ring-shaped outer exhaust gas jet (second volume flow 20) is through a valve modulated with a predetermined frequency spectrum (Fig. 4) and interferes at the outlet of the actuator A with the central beam 10. The actuator A is from Sensors, here microphones (Fig. 4) controlled, which the sound frequency spectrum to be canceled and possibly record the remaining sound. The Microphone signals are processed and used in a manner known per se as input signals for the modulation in the actuator. Because the two gas flows 10.20 approximately the same temperature (influence on the speed of sound) and the sound sources have almost the same position, leads to the superposition of the Sound waves for optimal, largely directionally insensitive extinction the unwanted noise.

Anstatt wie hier koaxial können die Leitungen 1,2 zur Verbesserung der Richtcharakteristik auch derart ineinander angeordnet sein, daß sie zwar weiterhin parallel verlaufen, ihre Achsen aber nicht mehr zusammenfallen.Instead of coaxial as here, the lines 1, 2 can be used to improve the directional characteristic also be arranged in such a way that they continue to be run parallel, but their axes no longer coincide.

In einer weiteren Variante können die beiden Ströme auch nebeneinander und z.B parallel geführt werden.In a further variant, the two streams can also coexist and e.g. run in parallel.

Der Aktuator kann alternativ auch mit Zapfluft aus einem vorhandenen Turbolader versorgt werden.Alternatively, the actuator can also use bleed air from an existing turbocharger be supplied.

Fig. 4 zeigt die Schnittzeichnung eine vorteilhaften Ausbildung einer erfindungsgemäßen Vorrichtung, wie sie z.B. in der Vorrichtung nach Fig. 3 eingesetzt werden kann. Auf die zentrale Leitung 1 (hier: Auspuffrohr für den Abgasstrahl einer Verbrennungsmaschine) für den ersten Volumenstrom 10 ist ein elektro-pneumatischer Aktuator A mit Ein- und Ausgängen für den zweiten Volumenstrom 20 aufgesetzt. Der zweite Volumenstrom 20 in der Leitung 2 kann sowohl aus der Leitung 1 für den ersten Volumenstrom 10 entnommen werden, als auch aus einem sonstigem, am Fahrzeug oder Aggregat vorhandenen Volumenstrom entnommen werden. Die zu tilgenden Schallwellen werden über eines oder mehrere Mikrophone M in der Leitung 1 erfaßt.Fig. 4 shows the sectional drawing of an advantageous embodiment of an inventive Device such as e.g. used in the device of FIG. 3 can be. On the central line 1 (here: exhaust pipe for the exhaust jet an internal combustion engine) for the first volume flow 10 an electro-pneumatic actuator A with inputs and outputs for the second Volume flow 20 placed. The second volume flow 20 in line 2 can be taken both from line 1 for the first volume flow 10 be, as well as from another, existing on the vehicle or unit Volume flow can be removed. The sound waves to be repaid are detected via one or more microphones M in line 1.

Auf dem Auspuffrohr 1 sind in dieser Ausführung drei kräftige, axial magnetisierte Ringmagnete 60 aufgefädelt. Die beiden äußeren Stirnseiten der Permanentmagnete 60 bilden einen Nordpol und einen Südpol. An einer Stirnseite sitzen die Magnete 60 in einem topfförmigen Gehäuse 62 aus Gußeisen, das zusammen mit dem Polschuh 64 am andereren Ende einen fast geschlossenen Magnetkreis bildet. In dem kleinen Luftspalt zwischen Polschuh 64 und dem Gehäuse 62 schwingt eine dünnwandige, zylinderförmige Spule (Ventilring) 66, die mit einem Ansteuersignal, abgeleitet von dem Ausgangsignal des Mikrofons M, beaufschlagt wird. Die Spule 66 ist an mehreren Federn (Blattfedern 67) aufgehängt. Der zu modulierende Gasstrom 20 wird durch Öffnungen im Gehäuseboden um die Magnete 60 herum in eine Vorkammer 68 und dann durch einen ringförmigen Spalt, dessen Weite von der schwingenden Spule 66 entsprechend dem gewählten Ansteuersignal variiert wird, zum Austritt geführt. Vorkammer 68, Spalt und Austrittsöffnung werden von dem austrittseitigen Deckel 65, der vor das topfförmige Gehäuse 62 geschraubt ist, begrenzt. Der austrittsseitige Bereich der Sekundärgasleitung 2 ist als Schalltrichter ausgebildet.In this embodiment, three powerful, axially magnetized are on the exhaust pipe 1 Threaded ring magnets 60. The two outer faces of the permanent magnets 60 form a north pole and a south pole. On one end the magnets 60 sit in a pot-shaped housing 62 made of cast iron, which together with the pole shoe 64 at the other end is almost closed Magnetic circuit forms. In the small air gap between pole shoe 64 and a thin-walled, cylindrical coil (valve ring) vibrates in the housing 62 66 with a drive signal derived from the output signal of the Microphone M is applied. The coil 66 is on several springs (leaf springs 67) hung up. The gas stream 20 to be modulated is through openings in the bottom of the housing around the magnets 60 into a prechamber 68 and then through an annular one Gap, the width of which corresponds to the oscillating coil 66 the selected control signal is varied, led to the exit. antechamber 68, gap and outlet opening are from the outlet-side cover 65, the is screwed in front of the cup-shaped housing 62, limited. The exit side The area of the secondary gas line 2 is designed as a sound funnel.

Abhängig vom Ansteuersignal kann mit dem beschriebenen Aktuator ein frei wählbares Schallfrequenzspektrum in dem ersten Volumenstrom 10 erzeugt werden.Depending on the control signal, an actuator can be used with the actuator described selectable sound frequency spectrum generated in the first volume flow 10 become.

Claims (21)

  1. Method for active noise reduction, there being a first (10) and a second volume flow (20), of which one (20) is varied in such a way that the noise reduction is effected during the subsequent interference between the two volume flows (10, 20) characterized in that the variation of the one volume flow (20) is carried out by means of modulation with a predefined frequency spectrum.
  2. Method according to Claim 1, characterized in that the second volume flow (20) is taken from the first volume flow.
  3. Method according to Claim 1, characterized in that the second volume flow (20) is taken from a volume flow that is already present, irrespective of the sound reduction.
  4. Method according to one of the preceding claims, characterized in that at least one of the two volume flows is taken from the exhaust gas flow of an internal combustion engine.
  5. Method according to Claim 3 or 4, characterized in that one (10) of the two volume flows is taken from the exhaust gas flow of an internal combustion engine, and the other volume flow (20) is taken from the gas flow of a turbocharger on the internal combustion engine.
  6. Method according to one of Claims 1 to 4, characterized in that at least one of the two volume flows is taken from the one vehicle.
  7. Method according to one of the preceding claims, characterized in that the two volume flows are guided in coaxial lines (1, 2) located one inside the other.
  8. Method according to Claim 7, characterized in that the two volume flows are guided in parallel lines located one inside the other but without a common axis.
  9. Method according to one of Claims 1 to 6, characterized in that the two volume flows are guided in parallel lines arranged beside each other.
  10. Method according to one of the preceding claims for producing a predetermined sound spectrum instead of for noise reduction.
  11. Device for active noise reduction, having a first line (1) to accommodate a first volume flow (10) and a second line (2) to accommodate a second volume flow (20), one (2) of the two lines (1, 2) being connected to the input of a device (A) which varies the volume flow (20) fed into the device (A) in such a way that the noise reduction is effected during the subsequent interference between the first (10) and second (20) volume flows, characterized in that the device (A) is an actuator with which the variation of the volume flow (20) can be carried out by means of modulation with a predefined frequency spectrum.
  12. Device according to Claim 11, characterized in that the two lines (1, 2) are connected to each other, so that one (20) of the two volume flows (20) can be taken from the other volume flow (10).
  13. Device according to Claim 11, characterized in that one (2) of the two lines comprises a connection for the introduction of a volume flow that is already present, irrespective of the noise reduction.
  14. Device according to one of Claims 11 to 13, characterized in that at least one of the two lines is connected to the exhaust gas line of an internal combustion engine.
  15. Device according to Claim 13 or 14, characterized in that one (1) of the two lines is connected to the exhaust gas line on an internal combustion engine, and the other line (2) comprises a connection for the introduction of the gas flow of a turbocharger present on the internal combustion engine.
  16. Device according to one of Claims 11 to 14, characterized in that the second line comprises a connection for the introduction of the wind of motion of a vehicle.
  17. Device according to one of the preceding claims, characterized in that the two lines (1, 2) are arranged to be located coaxially one inside the other.
  18. Device according to Claim 17, characterized in that the two lines are arranged to lie parallel one inside the other but without a common axis.
  19. Device according to one of Claims 11 to 16, characterized in that the two lines are arranged beside each other.
  20. Device according to one of Claims 17 to 19, characterized in that the actuator (A) is placed radially on one (1) of the two lines.
  21. Use of the device according to one of Claims 11 to 20 for producing a predetermined sound spectrum instead of for noise reduction.
EP97102834A 1996-05-02 1997-02-21 Method and device for active noise control of gas flows Expired - Lifetime EP0805431B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19617465A DE19617465C2 (en) 1996-05-02 1996-05-02 Method and device for active noise reduction
DE19617465 1996-05-02

Publications (3)

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EP0805431A2 EP0805431A2 (en) 1997-11-05
EP0805431A3 EP0805431A3 (en) 1999-10-20
EP0805431B1 true EP0805431B1 (en) 2002-04-24

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EP97102834A Expired - Lifetime EP0805431B1 (en) 1996-05-02 1997-02-21 Method and device for active noise control of gas flows

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EP (1) EP0805431B1 (en)
JP (1) JPH112113A (en)
DE (2) DE19617465C2 (en)
ES (1) ES2175205T3 (en)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2293076C (en) * 1999-12-22 2010-03-30 Man-Chun Tse Fan and compressor noise attenuation
DE10049884C1 (en) * 2000-10-10 2002-04-04 Horst Schmitt Noise protection device, for preventing environmental noise pollution, uses pressurized air or gas curtain for screening noise source
US9881602B2 (en) 2014-07-11 2018-01-30 Tenneco Gmbh Sound system for a motor vehicle
DE102017203182B4 (en) 2017-02-28 2021-09-02 Audi Ag Sound generating device for generating exhaust system sound and an associated motor vehicle
DE102017203181B4 (en) 2017-02-28 2021-08-26 Audi Ag Sound generating device for generating exhaust system sound and an associated motor vehicle
DE102017219573B4 (en) * 2017-11-03 2021-11-11 Cisma Solutions Aps Exhaust cover with sound source
DE202017007444U1 (en) 2017-11-03 2021-08-10 Cisma Solutions Aps Exhaust cover with sound source

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02136504A (en) * 1988-11-16 1990-05-25 Aisin Seiki Co Ltd Muffler of internal combustion engine
GB8928052D0 (en) * 1989-12-12 1990-02-14 Lotus Group Plc Control of pressure vibrations in ducts
DE4341951A1 (en) * 1992-12-17 1994-06-23 Volkswagen Ag Interference noise damper for exhaust gas system
US5325438A (en) * 1993-02-01 1994-06-28 At&T Bell Laboratories Active noise-cancellation system for automotive mufflers

Also Published As

Publication number Publication date
EP0805431A2 (en) 1997-11-05
DE19617465C2 (en) 1999-05-20
JPH112113A (en) 1999-01-06
ES2175205T3 (en) 2002-11-16
DE19617465A1 (en) 1997-11-13
EP0805431A3 (en) 1999-10-20
DE59707085D1 (en) 2002-05-29

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