WO1993009334A1 - Silencieux presentant une configuration creant un effet venturi - Google Patents

Silencieux presentant une configuration creant un effet venturi Download PDF

Info

Publication number
WO1993009334A1
WO1993009334A1 PCT/US1991/007831 US9107831W WO9309334A1 WO 1993009334 A1 WO1993009334 A1 WO 1993009334A1 US 9107831 W US9107831 W US 9107831W WO 9309334 A1 WO9309334 A1 WO 9309334A1
Authority
WO
WIPO (PCT)
Prior art keywords
exhaust pipe
loudspeaker
pipe
venturi effect
muffler
Prior art date
Application number
PCT/US1991/007831
Other languages
English (en)
Inventor
Andrew J. Langley
Original Assignee
Noise Cancellation Technologies, Inc.
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 Noise Cancellation Technologies, Inc. filed Critical Noise Cancellation Technologies, Inc.
Priority to PCT/US1991/007831 priority Critical patent/WO1993009334A1/fr
Priority to US08/211,838 priority patent/US5550334A/en
Priority to CA002121908A priority patent/CA2121908C/fr
Priority claimed from CA002121908A external-priority patent/CA2121908C/fr
Publication of WO1993009334A1 publication Critical patent/WO1993009334A1/fr

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L55/00—Devices or appurtenances for use in, or in connection with, pipes or pipe systems
    • F16L55/02—Energy absorbers; Noise absorbers
    • F16L55/033—Noise absorbers
    • F16L55/0333—Noise absorbers by means of an active system
    • 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

Definitions

  • the solution has typically resulted in a configuration that has a very short link between the loudspeaker and the pipe and wherein the loudspeaker is typically placed far from the engine for the benefit of reduced sound pressure and temperature.
  • the controller can then cancel the exhaust noise provided only one acoustic mode can propagate in the exhaust pipe over the control bandwidth.
  • the loudspeaker enclosure volume may be reduced somewhat and the diameter of the tail ⁇ pipe need not be larger than normal.
  • the instant invention manipulates the mean flow of the exhaust gases to cool the loudspeaker enclosure.
  • Either a full or partial venturi is used to generate an area that is below atmospheric pressure.
  • a bleed pipe allows ambient air to flow into this area thereby counteracting the flow of exhaust gases into the speaker area.
  • a filter can be provided in the bleed pipe to reduce the radiated noise.
  • a heat shield can be employed to protect the loudspeaker from the exhaust pipe or, instead, a reflective coated layer that conducts sound.
  • the configuration is designed to allow the cooling flow to maintain the exhaust gas concentration in the front cavity at a reasonable level.
  • a diffuser section can be used to accomplish this as well as a contracted section followed immediately by an expansion section. Cooling can also be accomplished by using the cooling fluid of the vehicle or by using separate fans. Both would entail additional expenditures and add a degree of complexity to the configuration.
  • Another object of this invention is to provide an actively controlled noiseless muffler having a short connection between the exhaust pipe and the loudspeaker enclosure.
  • a further object of this invention is to an active noise cancellation system for an exhaust system wherein the diameter/size of the exhaust pipe can be of standard size.
  • a still further object of this invention is to provide an actively controlled muffler configuration that prevents ingestion of exhaust gases into the loudspeaker enclosure.
  • Yet another object of this invention is the provision of a venturi means in an active noise cancellation exhaust system to create a differential pressure adjacent the speaker enclosure.
  • Fig 1 is a diagrammatic view of a standard active noise cancellation muffler
  • Fig 2 is a diagrammatic view of an improved configuration of an improved active noise cancellation muffler system
  • Fig 3 is a diagrammatic view of an in-pipe or venturi configuration in an improved active noise cancellation muffler
  • Fig 4 is a diagrammatic view of a venturi nozzle configuration in an active noise cancellation muffler to reduce radiation heating
  • Fig 5 is another diagrammatic view of an in-pipe or venturi configuration in an improved active noise cancellation muffler showing a separate heat shield
  • Fig 6 is a diagrammatic view of a partial venturi nozzle configuration in an active noise cancellation muffler.
  • Fig 1 shows a state-of-the-art active noise cancellation muffler having an exhaust pipe 1, a speaker enclosure 2 containing a loudspeaker 3 and having an extension which is co-axial and larger than pipe 1 and which also extends back beyond fender 5 and terminates in the same plane as pipe 1.
  • Fig 2 shows an improved system wherein the noise is cancelled directly in the muffler pipe.
  • Exhaust pipe 11 is directly open to enclosure 12 containing loudspeaker 13. There is no long extension or snout and the advantages of this configuration are
  • the link between the loudspeaker and the pipe can be very short, therefor reducing the moving mass;
  • the active system can be placed at any convenient location in the muffler pipe (although far from the engine has the benefits of reduced sound pressure and temperature);
  • the diameter of the tail-pipe on the muffler need be little, if any, larger than it would be on a passive system
  • the present invention manipulates the mean flow of the exhaust gases to force a clean, cooling airflow through the front (and/or back) cavities of the loudspeaker enclosure.
  • One configuration is shown in figure 3.
  • An exhaust pipe 21 has a reduced section as at 22 so as to produce a low pressure region at opening 23 into enclosure 24.
  • Loudspeaker 25 is mounted in enclosure 24 so as to cancel, by counter-sound, noise emanating at the exit 28.
  • the smooth contraction expansion (a "venturi") 22 is used to generate locally in the pipe a region that is below atmospheric pressure.
  • a bleed pipe 26 in the front cavity of the loudspeaker enclosure 24 permits air from outside to flow towards the low pressure region, thereby reducing ingestion of exhaust gases into the loudspeaker enclosure, and also providing cooling.
  • Bleed-pipe routing should avoid water traps ("sumps"), and it may be possible for the bleed pipe to drain the loudspeaker enclosure in the event of flooding.
  • the hole 42 in the muffler pipe 41 is arranged so that the loudspeaker is shielded by the muffler pipe itself. See figure 4.
  • a bleed pipe 45 conducts a cooling flow into speaker enclosure 44.
  • a separate heat shield 52 can be used in conjunction with exhaust pipe 51 with its opening 53 across from loudspeaker 54 in speaker enclosure 55.
  • a cooling flow is brought in through cooling bleed pipe 56.
  • the heat shield can be a reflective coated substratum that is acoustically transparent (e.g. a coated "foam”; overlapping, separated grids etc.) and span most or all of the width of the front cavity, or it can be a solid shield just large enough to "shadow" the diaphragm from the hot components without introducing significant acoustic blockage. It can be adequate just to have a reflective coating on heat-sensitive parts such as the diaphragm.
  • An exhaust pipe 61 is shown to have a partial venturi effect produced by split opening 62 which opens the pipe to speaker enclosure 63 containing loudspeaker 64 and bleed pipe 65.
  • Cooling with fluid e.g. by tapping into the engine-cooling circuit

Landscapes

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

Abstract

Dans un silencieux présentant des caractéristiques d'amortissement de bruit efficaces, on améliore des moyens produisant une zone (22) créant un effet venturi en position contiguë à une ouverture (23) située dans ledit silencieux, à proximité de laquelle est monté un haut-parleur (25) dans une enceinte (24), ladite zone à effet venturi (22) empêchant les gaz d'échappement chauds d'entrer en collision avec le haut-parleur (25).
PCT/US1991/007831 1991-10-30 1991-10-30 Silencieux presentant une configuration creant un effet venturi WO1993009334A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
PCT/US1991/007831 WO1993009334A1 (fr) 1991-10-30 1991-10-30 Silencieux presentant une configuration creant un effet venturi
US08/211,838 US5550334A (en) 1991-10-30 1991-10-30 Actively sound reduced muffler having a venturi effect configuration
CA002121908A CA2121908C (fr) 1991-10-30 1991-10-30 Silencieux utilisant l'effet venturi

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
PCT/US1991/007831 WO1993009334A1 (fr) 1991-10-30 1991-10-30 Silencieux presentant une configuration creant un effet venturi
CA002121908A CA2121908C (fr) 1991-10-30 1991-10-30 Silencieux utilisant l'effet venturi

Publications (1)

Publication Number Publication Date
WO1993009334A1 true WO1993009334A1 (fr) 1993-05-13

Family

ID=25677205

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1991/007831 WO1993009334A1 (fr) 1991-10-30 1991-10-30 Silencieux presentant une configuration creant un effet venturi

Country Status (1)

Country Link
WO (1) WO1993009334A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0674097A1 (fr) * 1994-02-22 1995-09-27 ELECTRONIC SOUND ATTENUATION S.p.A. Silencieux actif de gaz d'échappement
EP0679832A1 (fr) * 1994-04-26 1995-11-02 Lüthin, Heinz Dispositif de réduction de pulsations de pression dans conduits hydrauliques
US6758304B1 (en) * 1999-09-16 2004-07-06 Siemens Vdo Automotive Inc. Tuned Helmholtz resonator using cavity forcing
EP2105587B1 (fr) * 2008-03-27 2012-07-04 J. Eberspächer GmbH & Co. KG Installation de gaz d'échappement

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5044464A (en) * 1990-01-23 1991-09-03 Nelson Industries, Inc. Active acoustic attenuation mixing chamber
US5088575A (en) * 1990-09-13 1992-02-18 Nelson Industries, Inc. Acoustic system with transducer and venturi

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5044464A (en) * 1990-01-23 1991-09-03 Nelson Industries, Inc. Active acoustic attenuation mixing chamber
US5088575A (en) * 1990-09-13 1992-02-18 Nelson Industries, Inc. Acoustic system with transducer and venturi

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0674097A1 (fr) * 1994-02-22 1995-09-27 ELECTRONIC SOUND ATTENUATION S.p.A. Silencieux actif de gaz d'échappement
EP0679832A1 (fr) * 1994-04-26 1995-11-02 Lüthin, Heinz Dispositif de réduction de pulsations de pression dans conduits hydrauliques
US6758304B1 (en) * 1999-09-16 2004-07-06 Siemens Vdo Automotive Inc. Tuned Helmholtz resonator using cavity forcing
EP2105587B1 (fr) * 2008-03-27 2012-07-04 J. Eberspächer GmbH & Co. KG Installation de gaz d'échappement

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