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WO1998022700A2 - Amortisseur actif de bruit - Google Patents

Amortisseur actif de bruit Download PDF

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Publication number
WO1998022700A2
WO1998022700A2 PCT/EP1997/006441 EP9706441W WO9822700A2 WO 1998022700 A2 WO1998022700 A2 WO 1998022700A2 EP 9706441 W EP9706441 W EP 9706441W WO 9822700 A2 WO9822700 A2 WO 9822700A2
Authority
WO
WIPO (PCT)
Prior art keywords
chamber
hollow body
acoustic coupling
sound
storschall
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/EP1997/006441
Other languages
German (de)
English (en)
Inventor
Frank Jürgen LEHRINGER
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Leistritz AG and Co Abgastechnik
Original Assignee
Leistritz AG and Co Abgastechnik
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Leistritz AG and Co Abgastechnik filed Critical Leistritz AG and Co Abgastechnik
Priority to AU55530/98A priority Critical patent/AU5553098A/en
Publication of WO1998022700A2 publication Critical patent/WO1998022700A2/fr
Priority to DE59813377T priority patent/DE59813377D1/de
Priority to EP98121799A priority patent/EP0916817B1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES
    • F01N1/00—Silencing apparatus characterised by method of silencing
    • F01N1/06—Silencing apparatus characterised by method of silencing by using interference effect
    • F01N1/065—Silencing apparatus characterised by method of silencing by using interference effect by using an active noise source, e.g. speakers
    • 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
    • G10K11/1781—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 characterised by the analysis of input or output signals, e.g. frequency range, modes, transfer functions
    • G10K11/17821—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 characterised by the analysis of input or output signals, e.g. frequency range, modes, transfer functions characterised by the analysis of the input signals only
    • 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
    • G10K11/1781—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 characterised by the analysis of input or output signals, e.g. frequency range, modes, transfer functions
    • G10K11/17821—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 characterised by the analysis of input or output signals, e.g. frequency range, modes, transfer functions characterised by the analysis of the input signals only
    • G10K11/17825—Error signals
    • 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
    • G10K11/1783—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 handling or detecting of non-standard events or conditions, e.g. changing operating modes under specific operating conditions
    • 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
    • G10K11/17875—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
    • 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
    • G10K2210/3227—Resonators
    • G10K2210/32271—Active resonators
    • 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
    • G10K2210/50—Miscellaneous
    • G10K2210/51—Improving tonal quality, e.g. mimicking sports cars

Definitions

  • the invention relates to a silencer.
  • This arrangement contains a Helmholtz resonator.
  • a loudspeaker is integrated in this Helmholtz resonator in order to realize different cavity volumes of the Helmholtz resonator.
  • This active Helmholtz resonator absorbs the in its environment, e.g. B. existing noise in the passenger compartment of the motor vehicle. For this purpose, energy is extracted from the sound field in the vicinity of the Helmholtz resonator by converting sound energy into thermal energy through the bottle-neck-like entrance of the Helmholtz resonator.
  • WO-A-93 05282 From DE-A-4 317 403 and from WO-A-93 05282 arrangements for active sound attenuation are known, in which a chamber containing a loudspeaker is branched off from a noise channel. The loudspeaker should emit compensation sound in such a way that the two sound fields of interference sound and compensation sound cancel each other out or weaken each other through superimposition.
  • a control microphone is positioned at an unspecified location. In conjunction with a control unit, this control microphone should regulate the compensation sound of the loudspeaker in such a way that the attenuation or cancellation occurs at the location of the control microphone.
  • Such resonators are, for example, from “exhaust gas silencers for motor vehicles”, the library of technology vol 83, p 21, fig 13, vertag modern Industrie AG, 1993, ISBN 3-478-93076 -6 known t It is known here that a closed pipe piece is branched off in the manner of a resonator from a channel or a pipeline carrying the Storschall. The branch point forms an acoustic coupling point of the resonator. In this resonator, a sound field is in resonance when% of the wavelength or an odd number Many of them fit into the cavity of the resonator.
  • the disadvantage of this resonator is that good sound attenuation is only achieved if exactly 1 ⁇ of the wavelength or an odd multiple of it is equal to the acoustically effective length of the resonator
  • predetermined physical conditions at the acoustic coupling point forming an open resonator end and at a closed resonator end opposite the open resonator end.
  • the closed resonator end sound waves without phase jump, at the
  • the open resonator end is reflected with a phase shift of 180 °. Therefore, resonances are only zen and thus good sound damping possible
  • Another disadvantage with this resonator is that particularly large and thus space-consuming resonator lengths are required for damping low frequencies
  • the invention has for its object to provide a muffler that achieves a sound absorption adapted to the respective requirements with simple means
  • the hollow body is delimited by several walls. At least one wall or one wall segment - hereinafter "movable wall” - is movable from these walls
  • the invention is based on the consideration of influencing the propagation of the Storschalles in the Storschallkanal by means of the adaptation principle.
  • a sound field impedance is artificially forced in the area of the acoustic coupling point, which is adapted to the wave resistance of the Storschall channel in such a way that within of the Storschall channel sets the desired influencing of the Storschall.
  • This influencing is, for example, a total reflection of the Storschall at a so-called adaptation point in the Storschall channel, so that no Storschall propagates behind the adaptation point.
  • a setpoint of the sound field impedance is set in such a way, that the Storschall passes the adaptation point completely undamped If necessary, the setpoint of the sound field impedance is set in such a way that the Storschall is partly reflected at the adaptation point and partly transmitted, so that the Storschall spreads behind the adaptation point with a smaller sound amphtude Setpoint value can be dependent on certain frequencies of the Storschalles
  • an artificial noise design (sound design) is created by the sound damping by selecting a ge desired sound field impedance can be influenced deliberately.
  • different sound patterns can be generated from one and the same Storschall source
  • a device which determines the movement of the movable wall.
  • the movement function of the movable wall is coordinated in such a way that an actual value in the area of the acoustic coupling point Sound field impedance is enforced, which corresponds as closely as possible to the setpoint of this sound field impedance.
  • the selection and setting of the setpoint can, for example, be done automatically via an external manipulated variable (e.g. operating condition of the motor) or manually using a switch or several switches, a rotary knob or the like the setting element for setting the setpoint is part of a selection unit which is coupled to the above-mentioned device.
  • the setpoints which can be set are related to the sound field impedance in the area of the acoustic coupling point
  • the movement function of the movable wall is adjusted accordingly
  • the muffler thus enables an adjustable reflectance of the Storschallwellen in the area of the acoustic coupling point with the help of the movable wall at a plurality of frequencies.
  • the temporal movement function of the movable wall is determined or regulated according to amount and phase in such a way that for a frequency or a plurality of frequencies of the Storschalls the sound field impedance in the area of the acoustic coupling point is more or less adapted to the wave resistance of the Storschall canal as required
  • the hollow body is effectively used as a ⁇ / 4 resonator for a large number of frequencies of the Storschalls with the aid of the movable wall.
  • a minimal sound field impedance is set at the hollow body opening and the hollow body has essentially no changes in the direction of movement of the movable wall
  • Cross section on this resonator enables a particularly simple transfer function or a simple algorithm for controlling the movable wall. This also advantageously allows the control speed of the transfer function or the algorithm to be increased.
  • this hollow body enables the hollow body to be constructed in a structurally simple manner
  • the direction of movement of the movable wall runs transversely to the direction of propagation of the Storschall.
  • a tubular hollow body with its hollow body opening can be acoustically coupled to a Storschall channel in terms of production technology
  • the direction of movement of the movable wall runs parallel to the direction of propagation of the Storschalls, which means that the movable wall can be arranged within the muffler in a space-saving manner and no additional space has to be taken into account transversely to the direction of propagation.
  • This advantage is particularly useful when the movable wall is concerned is the membrane of a loudspeaker, which on the back of the membrane and thus outside the hollow body requires additional space to encapsulate it. which can be positioned well protected against the acoustic coupling point in the direction of propagation if this z. B. is required due to hot exhaust gases in the Storschallkanal. In this way, the possibly sensitive material of the movable wall is better protected against premature wear.
  • the measuring point can be positioned relatively far away from the acoustic coupling point, whereby, for example, a measuring device (eg pressure transducer; microphone) arranged in the measuring point is better protected from hot exhaust gases in the Storschallkanal for recording the sound pressure.
  • a measuring device eg pressure transducer; microphone
  • the device for regulating the actual value of the sound field impedance in the region of the acoustic coupling point is preferably part of a control loop which has a measuring device for measuring the sound pressure p and / or the sound velocity v. With the aid of this measuring device, the sound pressure p and / or the sound velocity v can be determined in the area of the acoustic coupling point.
  • the signal emitted by the measuring device to the control unit is processed in the control unit by means of an algorithm (eg LMS algorithm).
  • the control unit is designed, for example, in such a way that the sound field impedance is regulated to a minimum or a maximum in the area of the acoustic coupling point.
  • the movable wall is connected to an output of the control unit. With the help of electrical output signals from the control unit, the wall controlled.
  • the electrical output signals depending on the technical embodiment of the movable wall, for. B. converted into mechanical driving forces.
  • the movable wall is an electromechanical transducer, in particular the membrane of a loudspeaker, e.g. of an electrodynamic speaker.
  • electromechanical transducer in particular the membrane of a loudspeaker, e.g. of an electrodynamic speaker.
  • Such components are available inexpensively pre-assembled on the market and thereby keep the manufacturing costs of the silencer low. Components of this type can also be replaced cost-effectively if necessary.
  • the movable wall can also be constructed from a plurality of electromechanical transducers or a plurality of membranes from loudspeakers.
  • At least one sound pressure transducer or a sound pressure sensor is advantageously provided, which is connected to an input of the control unit.
  • the output of this control unit is connected to the movable wall and serves to drive it depending on the signals of the sound pressure transducer and the transfer function contained in the control unit.
  • the measuring device can also have at least one high-speed transducer.
  • the at least one fast sound transducer is effective either in combination with the at least one sound pressure transducer or alone.
  • the spatial orientation of the sound field impedance can be carried out by appropriate orientation of the high-speed transducer, whereby the damping effect can also be influenced.
  • the sound pressure transducer is advantageous due to a commercially available component, e.g. B. realized by an electromechanical transducer, in particular by a microphone, inexpensively.
  • the high-speed transducer is advantageously implemented by two spaced-apart sound pressure transducers.
  • the measuring device or the transducers used do not necessarily have to be positioned in the measuring point itself. Rather, it is also conceivable to position the transducers away from the measuring point.
  • the sound pressure transducer is positioned away from the measuring point and connected to the measuring point by a probe, e.g. a pipe probe.This probe is preferably passed through a movable wall of the hollow body.This positioning, which is distant from the measuring point, additionally protects the measuring device against hot exhaust gases or other harmful influences
  • the measuring point of the measuring device lies on a node of a higher mode of the hollow body sound field in the area of the acoustic coupling point.This is explained using the pressure node of the sound pressure.On the pressure node line is the sound pressure of the uneven wave field of this higher mode, which is in the hollow body of the Hollow body forms, zero The sound velocity on the corresponding sound velocity node is never zero.
  • the muffler contains two hollow bodies with a common area of an acoustic coupling point, the movable walls of the two resonators preferably being arranged opposite one another. This allows the required displacement path of a single movable wall to be divided into two movable walls, which advantageously results in a reduction in the mechanical and / or electrical power to control the individual movable wall
  • the two movable walls of the hollow bodies oscillate in phase opposition to one another.
  • These phase-opposite movements of the two movable walls are furthermore advantageously generated by a single control unit, which for this purpose contains one or more corresponding transmission functions or algorithms in the case of a design of the movable walls as loudspeakers, the latter are operated in opposite phase, for example, by reversing the polarity
  • the muffler In order to be able to manufacture the muffler compactly and in a material-saving manner, in an advantageous embodiment it contains a chamber through which the Storschallkanal passes.
  • This geometrical arrangement creates a cavity outside the Storschallkanal and inside the chamber, which acts as one or more hollow bodies is when the Storschallkanal within the chamber is acoustically coupled to this cavity
  • Storschallkanal carries hot exhaust gases
  • additional protection of the hollow body or the hollow body from these hot exhaust gases is achieved in a preferred embodiment of the muffler by virtue of the fact that the Storschallkanal is perforated at the acoustic coupling point or that the acoustic coupling point is formed by perforations Storschallkanal acoustically transparent and at the same time ensures that the hot exhaust gases remain essentially within the Storschallkanal
  • the chamber contains an inlet for connecting an inlet pipe and a chamber outlet for connecting an outlet pipe.
  • the chamber inlet and the chamber outlet of the Storschalls are arranged opposite one another. At least one of the two pipes protrudes into the chamber. the two pipes as components of the Storschall channel being arranged at a distance from one another. This distance is chosen such that it is used for acoustic coupling with the hollow body or with the hollow body is suitable and the arriving in the area of the acoustic coupling Storschallwellen can be influenced
  • the inlet pipe and the outlet pipe of the Storschall project approximately equally far into the chamber.
  • This symmetrical arrangement of the two pipes has the advantage that there is no need for assembly-intensive support measures for a section of the Storschall channel that projects particularly far into the chamber Applications of this muffler a simple support of the two pipes in the area of the chamber entrance or the chamber exit itself is sufficient
  • the outlet pipe has a larger pipe cross-section in the area of the acoustic coupling point than the inlet pipe.
  • the exhaust gas flow which is usually expanding or widening towards the hollow bodies at the transition point between the inlet pipe and the outlet pipe can be well adjusted isolate and forward in the direction of an exhaust gas mouth In this way, disturbing gas and air turbulence are avoided at the transition point between the inlet pipe and outlet pipe, so that the hollow body and then contained sensitive components, such as the sound pressure transducer, are additionally protected against hot exhaust gases
  • the movable wall in particular the membrane of an electromechanical transducer, is arranged approximately concentrically to the Storschall channel. If the Storschall channel contains an inlet pipe and an outlet pipe, the aforementioned concentric arrangement of the movable wall and at least one of the two Pipes provided The Storschallkanal or the pipe penetrates the movable wall, so to speak.
  • the knots of the higher modes of the hollow body sound field are used to position the section of the Storschall channel that crosses the chamber or to position the chamber entrance and / or the chamber outlet or the inlet pipe and / or the outlet pipe.
  • FIG. 2 shows a second embodiment of the muffler according to the invention with two hollow bodies
  • FIG. 3 shows an enlarged cross section of the chamber according to section line III-III in FIG. 1 with a representation of higher modes of the hollow body sound field
  • the active muffler like Figure 1 contains a single actively controlled hollow body 1
  • the cavity of this hollow body 1 is delimited by the inner jacket of a chamber 2 with a cylindrical cross section, the outer jacket of an inlet pipe 3 and by the membrane of a loudspeaker 4.
  • the membrane of the loudspeaker 4 forms a movable one Wall of the hollow body 1 and, like a chamber entrance 5 for connecting the inlet pipe 3 to an inlet end face 6 of the chamber 2, is arranged.
  • the inlet pipe 3 passes through the chamber entrance 5 and projects into a tungs ⁇ chtung 7 of the Storschalls into the chamber 2
  • the central longitudinal axis 8 of the inlet pipe 3 runs parallel to the direction of propagation 7
  • the pipe end of the inlet pipe 3 is axially spaced from one of the inlet end 6 in the direction of propagation 7 opposite end 9 of the chamber 2.
  • the outlet end 9 is from a chamber exit 10 penetrates, which is aligned with the chamber entrance 5
  • an outlet pipe 11 is connected, the cross section of which is identical to the cross section of the inlet pipe 3.
  • the two pipes 3, 11 have the same central longitudinal axis 8
  • the two pipes 3, 1 1 form a section of a Storschall channel in the area of the muffler, the input pipe 3 being connected to a Storschall source via a further section of the Storschall channel, not shown here, and the outlet pipe 1 1 z, for example, in hot exhaust gases contained in the Storschall channel
  • Direction of propagation 7 dissipates
  • the axial distance between the two pipes 3, 11 serves for acoustic coupling with the hollow body 1 in the area of an acoustic coupling point 12.
  • a hollow body opening 21 of the hollow body 1 is arranged in the area of this acoustic coupling point 12.
  • the cross section of the hollow body opening 21 is shown in FIG the axial distance between the inlet pipe 3 and the chamber outlet 10 is limited.
  • the adaptation point 22 is for influencing (e.g. total reflection, partial vaporization of the Storschallamphtude) in the direction of propagation 7 Spreading Storschalls arranged
  • This adaptation point 22 is located in the area of the pipe end of the input pipe 3, since the entire Storschall is present there
  • a setpoint value for the sound field impedance is selected and adjusted in such a way that the required damping effect is achieved.
  • the sound pressure converter 14 is positioned in a measuring point 17 for receiving the sound pressure at the coupling point 12.
  • the sound pressure converter 14, a control unit 15 and the loudspeaker 4 are connected in series and form a control loop 16 for regulating the sound pressure in the area of the coupling point 12 in such a way that eg sets a sound pressure minimum at the coupling point 12
  • a single measuring device namely the sound pressure transducer 14
  • the control unit 15 there are several measuring devices for measuring signals in the input of the control unit 15 Area of the acoustic coupling point 12 connected Depending on the setpoint of the sound field impedance that is set, either only a single measurement signal or a plurality of measurement signals that are linked to one another are processed in the control unit 15
  • the transverse dimension of the hollow body 1 is small to the wavelength, essentially flat sound waves propagate in the hollow body 1, so that for the positioning of the measuring point 17 or the sound pressure transducer 14, from an acoustic point of view, each location in a direction parallel to the section line III-III (see FIG 1) extending exit plane of the hollow body 1 in the area of the coupling point 12 is suitable.
  • the sound pressure transducer 14 can therefore run transversely to the direction of propagation 7 from hot exhaust gas can be positioned at a distance without the control loop 16 being affected.
  • the control loop 16 therefore continues to provide the desired value of the sound field impedance in the area of the coupling point 12
  • the pipes 3, 1 lead 1 hot exhaust gases additional protection of the hollow body 1 from the hot exhaust gases can be achieved in that the input pipe 3 is not - as shown in Fig. 1 - arranged at an axial distance from the chamber outlet 10, but up to Chamber exit 10 extends and is perforated in the area of the coupling point 12, in particular with high porosity to improve the acoustic permeability With this perforation, the inlet pipe 3 is acoustically transparent and at the same time protects the hollow body 1 and the sound pressure transducer 14 from the hot exhaust gases, which are essentially within the Inlet tube 3 and the adjoining outlet tube 11 protruding from the chamber 2 remain
  • the sound pressure measurement at the coupling point 12 takes place without restricting the function of the control loop 16 in such a way that although the measuring point 17 is still positioned in the area of the coupling point 12, the sound pressure transducer 14 itself is positioned at a distance from the measuring point 17 and is connected to the measuring point 17 via a probe.
  • the sound pressure transducer is designed, for example, as a probe microphone
  • the active muffler according to FIG. 2 contains two hollow bodies 1 ', each with a hollow body opening 21'.
  • the required displacement path of the membrane of the loudspeaker 4 according to FIG. 1 can be divided between the two membranes of the loudspeakers 4 'according to FIG. 2, thereby advantageously reducing the power of the individual Loudspeaker 4 '
  • the muffler contains, as it were, two symmetrically arranged hollow bodies 1' with respect to a plane of symmetry running transversely to the direction of propagation 7 or to the direction of movement 13 ' acoustic coupling point 12 'of the two hollow bodies 1' are the two pipes 3, 1 1 arranged for acoustic coupling with axial spacing from one another.
  • the control unit 15 'connected to a selection unit 23' is connected on the output side to both loudspeakers 4 ', the transmission functions or algorithms contained in the control unit 15' being related to the required operation of the Loudspeakers 4 are adapted.
  • the control unit 15 ' regulates, for example, the area of the hollow body openings 21' or the acoustic coupling point 12 'to a sound pressure minimum if a setpoint is set on the selection unit 23' such that the sound field impedance is set at the acoustic coupling point 12 ' Should set Z ⁇ 0
  • the two loudspeakers 4 ′ are operated in opposite phase by polarity reversal
  • the measuring point 17 has a higher mode pressure knot.
  • the measuring point 17 is on the pressure node 18 of the first radial mode and at the same time on a first pressure node 19 of the second circumferential mode.
  • the radial centers of the inlet tube 3 and the outlet tube 11 are approximately at the intersection of the pressure node 18 and the first pressure node 19 of the second fishing fashion.
  • a second pressure node 20 of the second circumferential mode is also shown in FIG. 3.
  • B. circular as in Fig. 3 or rectangular - can the measuring point 17 and / or the center of the input tube 3 and / or the center of the output tube 11 or the center of the chamber entrance 5 and / or the center of the chamber outlet 10 on different pressure node lines one higher fashion.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Soundproofing, Sound Blocking, And Sound Damping (AREA)
  • Exhaust Silencers (AREA)

Abstract

L'amortisseur actif de bruit selon l'invention présente un corps creux (1) comportant au moins une paroi mobile (4) et une ouverture (21). Il se caractérise par un couplage acoustique entre cette ouverture (21) et un canal de bruit perturbateur (3, 11), qui permet de diriger ce bruit. L'amortisseur actif est également doté d'un système (15) permettant de comparer une valeur prescrite réglable d'impédance de champ sonore avec une valeur réelle relevée dans la zone proche du point de couplage (12) acoustique, d'où la possibilité de déterminer le déplacement de la paroi mobile aux fins de l'ajustement de la valeur réelle sur la valeur prescrite.
PCT/EP1997/006441 1996-11-18 1997-11-18 Amortisseur actif de bruit Ceased WO1998022700A2 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
AU55530/98A AU5553098A (en) 1996-11-18 1997-11-18 Active exhaust silencer
DE59813377T DE59813377D1 (de) 1997-11-18 1998-11-17 Aktiver Schalldämpfer
EP98121799A EP0916817B1 (fr) 1997-11-18 1998-11-17 Silencieux actif

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19647568.6 1996-11-18
DE19647568 1996-11-18

Publications (1)

Publication Number Publication Date
WO1998022700A2 true WO1998022700A2 (fr) 1998-05-28

Family

ID=7811947

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP1997/006441 Ceased WO1998022700A2 (fr) 1996-11-18 1997-11-18 Amortisseur actif de bruit

Country Status (2)

Country Link
AU (1) AU5553098A (fr)
WO (1) WO1998022700A2 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0916817A3 (fr) * 1997-11-18 2002-10-30 Faurecia Abgastechnik GmbH Silencieux actif
FR3005993A1 (fr) * 2013-05-23 2014-11-28 Dcns Systeme de silencieux actif pour ligne d'echappement d'un moteur diesel notamment de plateforme navale
DE102013217849A1 (de) * 2013-09-06 2015-03-12 Friedrich Boysen Gmbh & Co. Kg Aktive Schallerzeugungseinrichtung
DE102017115271A1 (de) 2017-07-07 2019-01-10 Tenneco Gmbh Rauschunterdrückungssystem
WO2019007700A1 (fr) 2017-07-07 2019-01-10 Tenneco Gmbh Système de réduction de bruit

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0916817A3 (fr) * 1997-11-18 2002-10-30 Faurecia Abgastechnik GmbH Silencieux actif
FR3005993A1 (fr) * 2013-05-23 2014-11-28 Dcns Systeme de silencieux actif pour ligne d'echappement d'un moteur diesel notamment de plateforme navale
DE102013217849A1 (de) * 2013-09-06 2015-03-12 Friedrich Boysen Gmbh & Co. Kg Aktive Schallerzeugungseinrichtung
DE102017115271A1 (de) 2017-07-07 2019-01-10 Tenneco Gmbh Rauschunterdrückungssystem
WO2019007700A1 (fr) 2017-07-07 2019-01-10 Tenneco Gmbh Système de réduction de bruit
DE102017115271B4 (de) 2017-07-07 2019-04-18 Tenneco Gmbh Verfahren zum Betrieb eines Kraftfahrzeuggeräusch-Unterdrückungssystems

Also Published As

Publication number Publication date
AU5553098A (en) 1998-06-10

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