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EP0163024B1 - Reflexion exhaust silencer - Google Patents

Reflexion exhaust silencer Download PDF

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Publication number
EP0163024B1
EP0163024B1 EP85102989A EP85102989A EP0163024B1 EP 0163024 B1 EP0163024 B1 EP 0163024B1 EP 85102989 A EP85102989 A EP 85102989A EP 85102989 A EP85102989 A EP 85102989A EP 0163024 B1 EP0163024 B1 EP 0163024B1
Authority
EP
European Patent Office
Prior art keywords
exhaust
exhaust gas
silencer
pipe
opening
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.)
Expired
Application number
EP85102989A
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German (de)
French (fr)
Other versions
EP0163024A1 (en
Inventor
Alfons Zachmann
Hermann Ermer
Franz Lüftenegger
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
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Leistritz AG
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Filing date
Publication date
Application filed by Leistritz AG filed Critical Leistritz AG
Priority to AT85102989T priority Critical patent/ATE38410T1/en
Publication of EP0163024A1 publication Critical patent/EP0163024A1/en
Application granted granted Critical
Publication of EP0163024B1 publication Critical patent/EP0163024B1/en
Expired legal-status Critical Current

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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
    • F01N1/02—Silencing apparatus characterised by method of silencing by using resonance
    • 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
    • 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
    • F01N2490/00—Structure, disposition or shape of gas-chambers
    • F01N2490/15—Plurality of resonance or dead chambers
    • F01N2490/155—Plurality of resonance or dead chambers being disposed one after the other in flow direction

Definitions

  • the invention relates to a reflection exhaust muffler, in particular for internal combustion engines in motor vehicles, with exhaust pipes passing through the muffler chambers, with matched resonators being associated with the exhaust pipes of the exhaust muffler chamber on the inlet side.
  • the invention is therefore based on the object of providing a reflection-type exhaust silencer in which, by means of suitable design measures, such frequency levels which are in the pass band of the individual chambers are sufficiently attenuated.
  • the inlet exhaust pipe has a radial opening, spaced from the gas outlet opening to the muffler chamber, which is arched over by a sheet metal in such a way that two axial, crescent-shaped coupling openings in open the silencer chamber.
  • the acoustic decoupling via the special crescent-shaped coupling openings at a distance from the gas outlet openings results in a transit time difference between the sound components that exit the gas from the inlet exhaust pipe into the muffler chamber and the sound components that have only been acoustically coupled so that they Way real interference cancels can take place via runtime differences.
  • a blind-terminated pipe extension can be coupled to the outlet-side end of an exhaust pipe, the length of which is an odd multiple of a quarter of the mean sound wavelength to be canceled.
  • the blind end is preferably funnel-shaped or roof-shaped to achieve a favorable sound deflection - there are shifts between the incoming sound wave and the reflected sound wave at the beginning of the tube by odd multiples of half a wavelength, so that the incoming and the superimpose reflected wave in the sense of cancellation.
  • the pipe neck on the exhaust pipe can be a blind piece of the same diameter, a blind piece reduced in diameter by forming or attached by welding.
  • the design assumes that the exhaust pipe is provided with side openings for the gas outlet before the start of the blind piece.
  • the pipe extension is arranged at a distance from the exhaust gas outlet end opening of the coaxial exhaust pipe and is therefore essentially only acoustically coupled to it.
  • the first resonator comprises an opening 9 of the inlet exhaust pipe 6 for the first silencer chamber I, which is arched over by a sheet 10.
  • This sheet 10 is connected along the axial side edges 11 to the exhaust pipe 6, so that there are only sickle-shaped end openings 12 to the silencer chamber 1.
  • the length of the sheet 10 and its distance and thus also the size of the end openings 12 are chosen so that there is essentially no exhaust gas leakage these openings are made in the muffler chamber I, but a resonator is formed on the other side, which selectively dampens a certain predeterminable sound frequency range.
  • the embodiment according to FIG. 3 differs from the embodiment according to FIG. 2 in that the tube extension 13 is not welded directly to the end of the exhaust pipe 6, which of course requires lateral gas outlet openings 16 in the embodiment according to FIGS. 1 and 2. Instead, the exhaust pipe 6 is provided with an end outlet opening 17 which is coaxially opposite the inlet opening 15 of the pipe extension 13.
  • two partitions 3a and 3b are provided in order to deflect the exhaust gas into the front region of the muffler chamber I.
  • the Helmholtz resonator-type sound attenuation device is again provided through an inlet-side opening 9 of the exhaust pipe and a sheet 10 arching over it.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Exhaust Silencers (AREA)

Abstract

1. Reflex exhaust gas silencer, especially for internal combustion engines in motor vehicles, with exhaust gas pipes passing through the silencer chambers, tuned resonators being coordinated with the exhaust pipes at the inlet side of the exhaust gas silencer chamber, characterized in that the inlet exhaust pipe (6) comprises a radial opening (9) spaced from and upstream of the gas exhaust opening (16) to the silencer chamber (I), which opening is covered by an arched metal sheet (10) in such a manner that there are formed two axial, sickle-shaped coupling openings (12) which lead into the silencer chamber.

Description

Die Erfindung bezieht sich auf einen Reflexionsabgasschalldämpfer, insbesondere für Brennkraftmaschinen in Kraftfahrzeugen, mit die Schalldämpferkammern durchsetzenden Abgasrohren, wobei den Abgasrohren der eingangsseitigen Abgasschalldämpferkammer abgestimmte Resonatoren zugeordnet sind.The invention relates to a reflection exhaust muffler, in particular for internal combustion engines in motor vehicles, with exhaust pipes passing through the muffler chambers, with matched resonators being associated with the exhaust pipes of the exhaust muffler chamber on the inlet side.

In derartigen Reflexionsabgasschalldämpfern wird durch Vielfachreflexion in den einzelnen Schalldämpferkammern eine weitgehende Reduzierung der Schallenergie und damit die gewünschte Schalldämpfung erzielt. Diese unselektive mechanische Schallreduzierung infolge Vielfachreflexionen in den Kammern ermöglicht jedoch keine vollständige Schallauslöschung. Insbesondere gilt dies für solche Frequenzen, deren Wellenlängen zu den geometrischen Abmessungen der einzelnen Schalldämpferkammern in ungünstigem Verhältnis stehen und in den Durchlaßbereich fallen.In such reflection exhaust mufflers, multiple reflection in the individual muffler chambers results in a substantial reduction in the sound energy and thus the desired sound attenuation. However, this non-selective mechanical sound reduction due to multiple reflections in the chambers does not allow complete sound cancellation. This applies in particular to frequencies whose wavelengths are in an unfavorable ratio to the geometrical dimensions of the individual muffler chambers and fall within the pass band.

Der Erfindung liegt daher die Aufgabe zugrunde, einen Reflexionsabgasschalldämpfer zu schaffen, bei dem durch geeignete konstruktive Maßnahmen auch solche Frequenzpegel, die im Durchlaßbereich der einzelnen Kammern liegen, in ausreichendem Maße gedämpft werden.The invention is therefore based on the object of providing a reflection-type exhaust silencer in which, by means of suitable design measures, such frequency levels which are in the pass band of the individual chambers are sufficiently attenuated.

Zur Lösung dieser Aufgabe ist bei einem Reflexionsabgasschalldämpfer der eingangs genannten Art gemäß der Erfindung vorgesehen, daß das Einlaßabgasrohr eine, von der Gasaustrittsöffnung zur Schalldämpferkammer beabstandete, stromauf liegende radiale Öffnung aufweist, die von einem Blech derart überwölbt ist, daß zwei axiale, sichelförmige Koppelöffnungen in die Schalldämpferkammer münden.To solve this problem it is provided in a reflection exhaust silencer of the type mentioned according to the invention that the inlet exhaust pipe has a radial opening, spaced from the gas outlet opening to the muffler chamber, which is arched over by a sheet metal in such a way that two axial, crescent-shaped coupling openings in open the silencer chamber.

Durch die besondere Art der Auskopplung tritt praktisch kein Abgas unmittelbar in die entsprechende Schalldämpferkammer, sondern es findet lediglich eine akustische Auskopplung statt, wobei die Kammer nach Art von Helmholtz-Resonatoren so abgestimmt sein kann, daß ein gewünschter Frequenzbereich selektiv besonders stark bedämpft wird. Helmholtz-Resonator-Ausbildung in Verbindung mit der speziellen Auskopplung ist an sich bereits aus der britischen Patentschrift 1074562 bekannt. Dort ist aber die Schalldämpferkammer, in welche der Schall ausgekoppelt wird, nicht von Abgas durchströmt wie beim Anmeldungsgegenstand, so daß es an der für die erfindungsgemäße vollständige Schallvernichtung besonders wesentlichen zusätzlichen Interferenzauslöschung fehlt. Durch die akustische Auskopplung über die speziellen sichelförmigen Koppelöffnungen in Abstand von den Gasaustrittsöffnungen ergibt sich nämlich ein Laufzeitunterschied zwischen den Schallanteilen, die mit dem Gas aus dem EinlaßAbgasrohr in die Schalldämpferkammer austreten, zu den Schallanteilen, die nur akustisch ausgekoppelt worden sind, so daß auf diese Weise über Laufzeitunterschiede echte Interferenzauslöschungen stattfinden können.Due to the special type of decoupling, practically no exhaust gas enters directly into the corresponding silencer chamber, but only an acoustic decoupling takes place, the chamber being able to be tuned in the manner of Helmholtz resonators in such a way that a desired frequency range is particularly strongly damped selectively. Helmholtz resonator training in connection with the special coupling-out is already known per se from British patent specification 1074562. There, however, the muffler chamber into which the sound is coupled out does not have exhaust gas flowing through it, as in the subject of the application, so that there is no additional interference cancellation which is particularly important for the complete sound destruction according to the invention. The acoustic decoupling via the special crescent-shaped coupling openings at a distance from the gas outlet openings results in a transit time difference between the sound components that exit the gas from the inlet exhaust pipe into the muffler chamber and the sound components that have only been acoustically coupled so that they Way real interference cancels can take place via runtime differences.

In Weiterbildung der Erfindung kann an das auslaßseitige Ende eines Abgasrohrs ein blind endender Rohransatz angekoppelt sein, dessen Länge ein ungeradzahliges Vielfaches eines Viertels der auszulöschenden mittleren Schallwellenlänge ist.In a further development of the invention, a blind-terminated pipe extension can be coupled to the outlet-side end of an exhaust pipe, the length of which is an odd multiple of a quarter of the mean sound wavelength to be canceled.

Durch diesen Rohransatz - das blinde Ende ist bevorzugt trichter- oder dachkantförmig ausgebildet, um eine günstige Schallumlenkung zu erreichen - ergeben sich zwischen der einlaufenden Schallwelle und der reflektierten Schallwelle am Rohranfang Verschiebungen um jeweils ungeradzahlige Vielfache einer halben Wellenlänge, so daß sich die ankommende und die reflektierte Welle im Sinne einer Auslöschung überlagern.Through this tube approach - the blind end is preferably funnel-shaped or roof-shaped to achieve a favorable sound deflection - there are shifts between the incoming sound wave and the reflected sound wave at the beginning of the tube by odd multiples of half a wavelength, so that the incoming and the superimpose reflected wave in the sense of cancellation.

Der Rohransatz am Abgasrohr kann ein im gleichen Durchmesser gehaltenes Blindstück, ein durch Umformung im Durchmesser reduziertes oder durch Anschweißen angesetztes Blindstück sein. Die Konstruktion setzt voraus, daß vor Beginn des Blindstückes das Abgasrohr mit seitlichen Öffnungen für den Gasaustritt versehen ist.The pipe neck on the exhaust pipe can be a blind piece of the same diameter, a blind piece reduced in diameter by forming or attached by welding. The design assumes that the exhaust pipe is provided with side openings for the gas outlet before the start of the blind piece.

Stattdessen ist es aber auch in Ausgestaltung der Erfindung möglich, daß der Rohransatz in Abstand von der Abgasaustritts-Stirnöffnung des koaxialen Abgasrohrs angeordnet und somit im wesentlichen nur akustisch daran angekoppelt ist.Instead, however, it is also possible in an embodiment of the invention that the pipe extension is arranged at a distance from the exhaust gas outlet end opening of the coaxial exhaust pipe and is therefore essentially only acoustically coupled to it.

Weitere Vorteile, Merkmale und Einzelheiten der Erfindung ergeben sich aus der nachfolgenden Beschreibung einiger Ausführungsbeispiele, sowie anhand der Zeichnung. Dabei zeigen:

  • Fig. 1 einen Längsschnitt durch einen erfindungsgemäß ausgestalteten, mit zwei selektiven Bedämpfungsresonatoren versehenen Reflexions-Abgasschalldämpfer,
  • Fig. 2 einen Querschnitt längs der Linie 11-11 und
  • Fig. 3 einen Längsschnitt durch einen abgewandelten Reflexions-Abgasschalldämpfer mit nur akustischer Ankopplung des Resonator-Rohransatzes.
Further advantages, features and details of the invention emerge from the following description of some exemplary embodiments and from the drawing. Show:
  • 1 shows a longitudinal section through a reflection exhaust gas silencer designed according to the invention and provided with two selective damping resonators,
  • Fig. 2 shows a cross section along the line 11-11 and
  • Fig. 3 shows a longitudinal section through a modified reflection exhaust silencer with only acoustic coupling of the resonator tube attachment.

Im Gehäuse 1 des Abgasschalldämpfers gemäß den Fig. 1 und 2 sind durch Querwände 3, 4 und 5 Reflexions-Kammern 1, 11111 usw. gebildet, die von unterbrochenen Abgasrohren 6, 7, 8 usw. durchsetzt werden. Diese an sich bekannte Konstruktion von Abgasschalldämpfern braucht an dieser Stelle nicht näher erläutert zu werden.1 and 2 are formed by transverse walls 3, 4 and 5 reflection chambers 1, 11111 etc., which are penetrated by interrupted exhaust pipes 6, 7, 8, etc. in the housing 1 of the exhaust silencer according to FIGS. This known construction of exhaust silencers need not be explained in more detail here.

Gemäß der vorliegenden Erfindung sind selektive Resonatorbedämpfungseinrichtungen vorgesehen. Der erste Resonator umfaßt eine Öffnung 9 des Einlaßabgasrohrs 6 für die erste Schalldämpferkammer I, die durch ein Blech 10 überwölbt ist. Dieses Blech 10 ist längs axialer Seitenränder 11 mit dem Abgasrohr 6 verbunden, so daß nur sichelförmige Stirnöffnungen 12 zur Schalldämpferkammer 1 bestehen. Die Länge des Blechs 10 und sein Abstand und damit auch die Größe der Stirnöffnungen 12 sind so gewählt, daß im wesentlichen kein Abgasaustritt durch diese Öffnungen in die Schalldämpferkammer I erfolgt, daß aber auf der anderen Seite ein Resonator gebildet ist, der einen bestimmten vorgebbaren Schallfrequenzbereich selektiv bedämpft.According to the present invention, selective resonator damping devices are provided. The first resonator comprises an opening 9 of the inlet exhaust pipe 6 for the first silencer chamber I, which is arched over by a sheet 10. This sheet 10 is connected along the axial side edges 11 to the exhaust pipe 6, so that there are only sickle-shaped end openings 12 to the silencer chamber 1. The length of the sheet 10 and its distance and thus also the size of the end openings 12 are chosen so that there is essentially no exhaust gas leakage these openings are made in the muffler chamber I, but a resonator is formed on the other side, which selectively dampens a certain predeterminable sound frequency range.

Eine weitere Möglichkeit einer solchen selektiven Bedämpfung ist am austrittsseitigen Ende des Abgasrohrs 6 dargestellt. An dieses Ende ist ein Rohrstutzen angeschweißt, der am abgelegenen Ende 14 blind endet, so daß in ihn einlaufende Schallwellen reflektiert und zum Eingang 15 zurückgeworfen werden. Durch Abstimmung der Länge dieses Rohransatzes 13 auf ein gewünschtes, möglichst stark zu bedämpfendes, Frequenzband derart, daß gilt L = n . k, wobei n eine ungerade ganze Zahl und λ die mittlere Wellenlänge des zu bedämpfenden Schallfrequenzbandes ist, ergibt sich eine solche Überlagerung, daß die jeweils einlaufende Welle und die reflektierte Welle am Eingang 15 des Rohransatzes sich im Sinne einer Auslöschung überlagern.Another possibility for such a selective damping is shown at the outlet end of the exhaust pipe 6. A pipe socket is welded to this end, which ends blindly at the remote end 14, so that sound waves entering it are reflected and reflected back to the entrance 15. By matching the length of this tube extension 13 to a desired frequency band to be damped as much as possible such that L = n. k, where n is an odd integer and λ is the mean wavelength of the sound frequency band to be attenuated, there is such a superimposition that the incoming wave and the reflected wave at the input 15 of the pipe socket overlap in the sense of cancellation.

Die Ausführungsform gemäß Fig. 3 unterscheidet sich von der Ausführungsform nach Fig. 2 dadurch, daß der Rohransatz 13 nicht unmittelbar an das Ende des Abgasrohrs 6 angeschweißt ist, was bei der Ausführungsform nach den Fig. 1 und 2 es selbstverständlich seitliche Gasaustrittsöffnungen 16 erfordert. Stattdessen ist das Abgasrohr 6 mit einer Stirnaustrittsöffnung 17 versehen, der in Abstand die Eingangsöffnung 15 des Rohransatzes 13 koaxial gegenüberliegt. Bei dieser Ausführungsform sind zwei Trennwände 3a und 3b vorgesehen, um die Abgasumlenkung in den vorderen Bereich der Schalldämpferkammer I zu bewirken. Im übrigen ist auch bei dieser Ausführungsform nach Fig. 3 wieder die Helmholtzresonator-artige Schallbedämpfungseinrichtung durch eine eingangsseitige Öffnung 9 des Abgasrohrs und ein diese überwölbendes Blech 10 vorgesehen.The embodiment according to FIG. 3 differs from the embodiment according to FIG. 2 in that the tube extension 13 is not welded directly to the end of the exhaust pipe 6, which of course requires lateral gas outlet openings 16 in the embodiment according to FIGS. 1 and 2. Instead, the exhaust pipe 6 is provided with an end outlet opening 17 which is coaxially opposite the inlet opening 15 of the pipe extension 13. In this embodiment, two partitions 3a and 3b are provided in order to deflect the exhaust gas into the front region of the muffler chamber I. For the rest, in this embodiment according to FIG. 3, the Helmholtz resonator-type sound attenuation device is again provided through an inlet-side opening 9 of the exhaust pipe and a sheet 10 arching over it.

Claims (4)

1. Reflex exhaust gas silencer, especially for internal combustion engines in motor vehicles, with exhaust gas pipes passing through the silencer chambers, tuned resonators being coordinated with the exhaust pipes at the inlet side of the exhaust gas silencer chamber, characterised in that the inlet exhaust pipe (6) comprises a radial opening (9) spaced from and upstream of the gas exhaust opening (16) to the silencer chamber (I), which opening is covered by an arched metal sheet (10) in such a manner that there are formed two axial, sickle-shaped coupling openings (12) which lead into the silencer chamber.
2. Reflex exhaust gas silencer according to Claim 1, characterised in that a blind ending extension pipe (13) is coupled at the outlet end of an exhaust pipe (6), the length of the extension pipe being an odd-numbered multiple of a quarter of the average wavelength of sound to be silenced.
3. Reflex exhaust gas silencer according to Claim 2, characterised in that the extension pipe (13) is connected directly to the exhaust pipe (6) provided with lateral exhaust gas outlet openings (16).
4. Reflex exhaust gas silencer according to claim 2, characterised in that the extension pipe (13) is arranged at a spacing from the exhaust gas outlet opening (17) at the end of the coaxial exhaust pipe (6).
EP85102989A 1984-05-09 1985-03-15 Reflexion exhaust silencer Expired EP0163024B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT85102989T ATE38410T1 (en) 1984-05-09 1985-03-15 REFLECTION EXHAUST SILENCER.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3417131 1984-05-09
DE19843417131 DE3417131A1 (en) 1984-05-09 1984-05-09 REFLECTION EXHAUST SILENCER

Publications (2)

Publication Number Publication Date
EP0163024A1 EP0163024A1 (en) 1985-12-04
EP0163024B1 true EP0163024B1 (en) 1988-11-02

Family

ID=6235342

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85102989A Expired EP0163024B1 (en) 1984-05-09 1985-03-15 Reflexion exhaust silencer

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EP (1) EP0163024B1 (en)
AT (1) ATE38410T1 (en)
DE (1) DE3417131A1 (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE29607010U1 (en) * 1996-04-18 1997-08-14 Heinrich Gillet Gmbh & Co Kg, 67480 Edenkoben Silencer
KR101283242B1 (en) 2010-10-08 2013-07-11 현대자동차주식회사 Muffler for vehicle
DE102015118573A1 (en) * 2015-10-30 2017-05-04 Eberspächer Exhaust Technology GmbH & Co. KG Silencer for an exhaust system of an internal combustion engine

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE949974C (en) * 1953-04-14 1956-09-27 Friedrich Boysen Silencer for pulsating currents, especially for the exhaust of motor vehicle internal combustion engines
US2922485A (en) * 1955-09-19 1960-01-26 Gen Motors Corp Muffler
DE1787803U (en) * 1959-01-29 1959-04-30 Schuenemann & Co PIPE-SHAPED SILENCER.
US3209858A (en) * 1963-06-25 1965-10-05 Walker Mfg Co Muffler having depressed channel forming tuning passages
US3402785A (en) * 1965-10-23 1968-09-24 Walker Mfg Co Muffler with resonance chambers for high and low frequencies
GB1513473A (en) * 1974-08-28 1978-06-07 Yamaha Motor Co Ltd Method and apparatus for silencing the exhaust noise of internal combustion engines
DE2856889A1 (en) * 1978-12-30 1980-11-20 Zeuna Staerker Kg Motor vehicle exhaust silencer - has twin pipes with vents in partitioned cowling

Also Published As

Publication number Publication date
DE3417131C2 (en) 1988-11-24
ATE38410T1 (en) 1988-11-15
EP0163024A1 (en) 1985-12-04
DE3417131A1 (en) 1985-11-21

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