EP0020508B1 - Pot d'echappement pour mouteur a pistons d un avion - Google Patents

Pot d'echappement pour mouteur a pistons d un avion Download PDF

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Publication number
EP0020508B1
EP0020508B1 EP79901368A EP79901368A EP0020508B1 EP 0020508 B1 EP0020508 B1 EP 0020508B1 EP 79901368 A EP79901368 A EP 79901368A EP 79901368 A EP79901368 A EP 79901368A EP 0020508 B1 EP0020508 B1 EP 0020508B1
Authority
EP
European Patent Office
Prior art keywords
sheets
cooling
slot
outlet opening
lateral
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
EP79901368A
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German (de)
English (en)
Other versions
EP0020508A1 (fr
Inventor
Phillip Erich Stauch
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.)
Individual
Original Assignee
Individual
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
Priority to AT79901368T priority Critical patent/ATE1530T1/de
Application filed by Individual filed Critical Individual
Publication of EP0020508A1 publication Critical patent/EP0020508A1/fr
Application granted granted Critical
Publication of EP0020508B1 publication Critical patent/EP0020508B1/fr
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
    • F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
    • F01N13/20—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00 having flared outlets, e.g. of fish-tail shape
    • 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
    • F01N1/08—Silencing apparatus characterised by method of silencing by reducing exhaust energy by throttling or whirling

Definitions

  • the invention relates to a silencer for piston aircraft engines with inner perforated plates and at least one tubular connecting piece for connection to an exhaust pipe, which has a rectangular cross section with a changing configuration in the flow direction, in which the front and rear outer plates assigned to the long sides of the rectangle in the flow direction converge towards each other up to a slit-like outlet opening and the lateral end plates assigned to the shorter sides of the rectangle diverge in the flow direction to each other up to the slit-like outlet opening.
  • the invention is thus based on GB-A-278 857, in which a silencer is described with converging and diverging outer sheets facing each other in pairs.
  • This configuration of a silencer was chosen so that the metal sheets converging up to the slot-like outlet opening can be designed to be resilient, so that a type of check valve is formed in the area of the outlet opening.
  • this known configuration of a silencer is selected as a starting point for another purpose.
  • Piston aircraft engine propeller airplanes which are mainly used as private travel and sports aircraft, normally have no silencers.
  • the noise limits set by the authorities therefore make it necessary to design the engines so that the exhaust noise does not exceed these limits. So you don't have a free hand to optimize the valve times and the speed with a view to a possible maximum performance of the engine.
  • the official regulations on noise limits result in a kind of throttling of the aircraft engines as long as they work without a silencer.
  • a silencer always means a certain loss of performance.
  • the invention has for its object to provide a silencer for piston aircraft engines, which lowers the noise level without affecting the speed-dependent performance of the aircraft engine.
  • This object is achieved by the features a) and b) specified in the characterizing part of patent claim 1.
  • the outer design of a known silencer is used in the context of the invention, which has a rectangular cross section with a changing configuration in the flow direction. Due to the divergence of the side end plates, which is gradually larger than the convergence of the front and rear outer plates representing the long sides of the cross-sectional rectangle, the surfaces of the converging outer plates are greatly enlarged up to the slot-like outlet opening without the cross-sectional area of the interior of the muffler in Flow direction must increase.
  • a swirl chamber delimited by the outer and end plates be provided between the area of the cooling chambers and the connecting piece, in which a strip-like baffle angle extending between the side end plates is arranged.
  • This impact angle acts as a reflection surface for sound waves and at the same time for deflecting and dividing the exhaust gas flow in order to reduce the speed component of the exhaust gas flow and to favor that the exhaust gases enter as many holes as possible in the perforated plates which extend essentially in the flow direction.
  • the diverging side end plates which the propeller wind also sweeps past, are only used for the cooling effect in the area of the swirl chamber and the end faces of the two aforementioned cooling chambers.
  • the features of claim 3 ensure that partial flows of the exhaust gases are also subjected to cooling by air flowing past in the area of the narrow lateral end faces of the muffler.
  • a further improvement in the cooling effect is obtained if the muffler according to claim 4 is traversed by a cooling slot open in the area of the side end plates, which allows outside air to enter the interior of the muffler and whose side walls from the exhaust gases extend into the slot-like outlet opening are washed around.
  • the exhaust gases are cooled not only by heat transfer via the converging outer plates, but also by heat transfer on the walls of the cooling slot.
  • the cross section of the slot-like outlet opening for the exhaust gases should be approximately as large as the cross section of the connecting piece. This means that an expansion of the exhaust gases within the muffler is not sought, since the exhaust gases decrease in volume due to strong cooling. Because of the decrease in volume of the exhaust gases, the slot-like outlet opening can even be smaller in cross section than that of the connecting piece.
  • the total cross-section of the holes in the perforated plates is expediently larger than the cross-section of the inlet-side connection piece, in order to avoid any backflow of exhaust gases within the silencer.
  • the front and rear outer plates expediently enclose a convergence angle of 12 ° and the side end plates an angle of divergence of 40 °.
  • the cooling air i.e. sheet metal that is coated with the propeller wind
  • the cooling air can be provided with web plates to enlarge the heat-transferring surfaces and to guide the cooling air.
  • a muffler according to the invention consists in all embodiments of a tubular connection piece 1 for connecting the muffler to an exhaust pipe, a rectangular or square transition flange 2 as a connection for other outer wall parts of the muffler, which result in a rectangular cross section of an interior.
  • These outer wall parts consist of front and rear outer plates 3 and 4, which converge at an angle of approximately 12 °, as shown in FIG. 2, and of narrower side end plates 5 and 6, which diverge in the direction of flow and enclose a divergence angle of approximately 40 °.
  • the length of the converging outer sheets 3 and 4 is such that they result in a slot-like outlet opening 7.
  • the length of the slot-like outlet opening 7 results from the divergence of the side end plates 5 and 6, and it is ensured by these dimensional relationships that the cross section of the slot-like outlet opening 7 is approximately as large as the cross section of the inlet-side connecting piece 1.
  • each perforated plate with a bevel, a front or rear outer plate and areas of the lateral, mutually diverging end plates forms a cooling chamber 10 or 11.
  • Each cooling chamber runs into the slot-like outlet opening 7.
  • the perforated plates 8 and 9 can be brought together in the area of the outlet opening 7, but they can also leave a narrow, proportionate slot in the outlet opening 7 free.
  • a swirl chamber 12 which is delimited by the outer and end plates 3 to 6 and in which a strip-like baffle angle 13 extending between the side end plates 5,6 is arranged.
  • cooling hoods 16 and 17 are therefore provided outside the lateral end plates 5, 6, the channel-like interior spaces of which are connected to the swirl chamber 12 via holes 18 in the upper region of the end plates 5, 6.
  • the interiors of the cooling hoods 16, 17 are also connected to the two cooling chambers 10, 11 via holes 19, so that two partial flows from the swirl chamber 12 into the cooling hoods and from there into the cooling chambers 10, 11 open at the bottom.
  • the flow of the exhaust gases is shown in Fig.
  • the embodiment according to FIGS. 5 to 7 essentially corresponds to the embodiment according to FIGS. 1 and 2.
  • the deviation consists in an inner cooling slot 22 which is limited on the inflow side by the strip-shaped baffle angle 13 on which there are a pair of walls 20 and 21 connects. These walls 20, 21 extend through the narrowing space 14 (FIG. 2) between the lateral cooling chambers 10, 11 into the area of the outlet opening 7.
  • the outlet slot 23 is for the cooling slot 22 between the partial outlet slots 24, 25 of the cooling chambers 10, 11.
  • the cooling slot 22 is open to the side for the entry of cooling air in that the side end plates 5, 6 are open over the distance between the walls 20, 21, as shown in the sectional view 5, right half, emerges.
  • the direction of the incoming cooling air is also shown here with dashed arrows, whereas in all other figures the solid arrows indicate the direction of flow of exhaust gases.
  • a pair of web plates 26, 27 are placed on the side end plates 5, 6 on both sides of the cooling slot 22, which not only enlarge the heat-transferring surfaces to improve the cooling effect, but also serve to guide the cooling air .
  • a pair of web plates 27 are inclined to one another in the flow direction in such a way that the cooling air flow coming from above is forced into the cooling slot 22 by narrowing a flow channel.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Exhaust Silencers (AREA)
  • Adhesives Or Adhesive Processes (AREA)
  • Vibration Prevention Devices (AREA)
  • Fluid-Damping Devices (AREA)

Claims (8)

1. Pot d'échappement pour moteur à pistons d'un avion comportant des tôles intérieures perfore'es et au moins un manchon tubulaire de raccordement à un conduit de gaz d'échappement, et ayant: une section transversale rectangulaire d'une configuration variant dans le sens de l'écoulement et dans laquelle les tôles extérieures avant et arrière (3, 4) associées aux longs côtés du rectangle convergent l'une vers l'autre dans le sens de l'écoulement jusqu'à une ouverture de sortie (7) en forme de fente, tandis que les tôles latérales de fermeture (5, 6) associées aux petits côtés du rectangle divergent l'une par rapport à l'autre dans le sens de l'écoulement jusqu'à l'ouverture de sortie en forme de fente, caractérisé par:
a) des tôles perforées convergentes (8, 9) écartées parallèlement des tôles extérieures avant et arrière (3, 4), convergeant l'une vers l'autre et comportant des rebords (8a, 9a) situées du côté de l'admission et s'étendant vers ces tôles extérieures convergentes de telle sorte qu'avec un rebord, une tôle extérieure avant ou arrière (3, 4) et des zones des tôles latérales de fermeture (5, 6) divergeant l'une par rapport à l'autre, chaque tôle perforée forme une chambre de refroidissement (10, 11) ouverte et débouchant dans l'ouverture de sortie (7) en forme de fente,
b) cette chambre de refroidissement recevant les gaz d'échappement venant de la chambre intermédiaire (14) allant en se rétrécissant entre les tôles perforées convergentes (8, 9) et à travers les trous (15) pratiqués dans ces dernières, pour les laisser s'échapper dans la zone de l'ouverture de sortie en forme de fente si bien que, après avoir été déviés dans les chambres de refroidissement (10, 11), les gaz d'échappement passent le long des tôles extérieures et latérales de fermeture, lesquelles entrent en contact avec le souffle de l'hélice.
2. Pot d'échappement suivant la revendication 1, caractérisé en ce que, entre la zone des chambres de refroidissement (10, 11) et le manchon de raccordement (1), est délimitée, par les tôles extérieures et de fermeture:
a) une chambre de tourbillonnement (12) dans laquelle est située; entre les tôles latérales de fermeture (5, 6):
b) une pièce angulaire (13) du type à baguette formant chicane.
3. Pot d'échappement suivant la revendication 1 et 2, caractérisé en ce que, à l'extérieur des tôles latérales de fermeture (5, 6), sont prévues:
a) des hottes de refroidissement (16, 17) dont les chambres intérieures en forme de canaux sont reliées
b) par des trous (18,19) pratiqués dans les tôles latérales de fermeture, avec la chambre de tourbillonnement (12), ainsi qu'avec les deux chambres de refroidissement (10, 11), de telle sorte que,
c) deux courants partiels des gaz d'échappement soient acheminés de la chambre de tourbil- tonhement dans les hottes de refroidissement et de là, dans les chambres de refroidissement ouvertes.
4. Pot d'échappement suivant la revendication 1 et 2, caractérisé en ce que deux parois parallèles (20, 21) sont assemblées à la pièce angulaire (13) formant chicane, ces parois formant une fente de refroidissement (22) s'étendant dans la chambre (14) intermédiaire allant en se rétrécissant entre les chambres de refroidissement (10, 11),
a) cette fente de refroidissement (22) étant ouverte dans la zone des tôles latérales de fermeture pour permettre la pénétration de l'air extérieur, tandis que
b) elle se termine en une ouverture de sortie (23) en forme de fente.
5. Pot d'échappement suivant une ou plusieurs des revendications précédentes, caractérisé en ce que l'ouverture de sortie (7) en forme de fente pour les gaz d'échappement a une section transversale à peu près aussi grande que celle du manchon de raccordement (1).
6. Pot d'échappement suivant la revendication 5, caractérisé en ce que la somme des sections transversales des trous (15) pratiqués dans les tôles perforées (8, 9) est supérieure à celle du manchon de raccordement (1).
7. Pot d'échappement suivant la revendication 1, caractérisé en ce que les tôles extérieures avant et arrière (3, 4) ont un angle de convergence d'environ 12°, tandis que les tôles latérales de fermeture (5, 6) ont un angle de divergence d'environ 40°.
8. Pot d'échappement suivant une ou plusieurs des revendications précédentes, caractérisé en ce que des ailettes (26, 27) sont fixées sur les tôles (5, 6) entrant en contact avec l'air de refroidissement afin d'accroître les surfaces de transfert de chaleur et de guider cet air de refroidissement.
EP79901368A 1978-10-21 1980-05-07 Pot d'echappement pour mouteur a pistons d un avion Expired EP0020508B1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT79901368T ATE1530T1 (de) 1978-10-21 1979-10-22 Schalldaempfer fuer kolben-flugmotoren.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE2845902A DE2845902C2 (de) 1978-10-21 1978-10-21 Schalldämpfer für Kolben-Flugmotoren
DE2845902 1978-10-21

Publications (2)

Publication Number Publication Date
EP0020508A1 EP0020508A1 (fr) 1981-01-07
EP0020508B1 true EP0020508B1 (fr) 1982-09-08

Family

ID=6052774

Family Applications (1)

Application Number Title Priority Date Filing Date
EP79901368A Expired EP0020508B1 (fr) 1978-10-21 1980-05-07 Pot d'echappement pour mouteur a pistons d un avion

Country Status (7)

Country Link
US (1) US4315560A (fr)
EP (1) EP0020508B1 (fr)
JP (1) JPS55500832A (fr)
AT (1) ATE1530T1 (fr)
BR (1) BR7908869A (fr)
DE (1) DE2845902C2 (fr)
WO (1) WO1980000861A1 (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE464097B (sv) * 1987-06-18 1991-03-04 Claes Linden Utblaasningsroer verkande som resonator vid foerbraenningsmotor
US5930036A (en) * 1997-03-02 1999-07-27 Cluff; Kenneth L. Binocular spotting scope assembly
US7207258B1 (en) 2004-12-10 2007-04-24 United States Of America As Represented By The Secretary Of The Army Weapon silencers and related systems

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE341516C (fr) *
DE447476C (de) * 1925-09-06 1927-07-26 Leopold Podszus Auspufftopf fuer Explosionsmotoren
GB263701A (en) * 1926-08-17 1927-01-06 Horace Hamilton Russell Improvements relating to exhaust silencers for internal combustion engines
GB278857A (en) * 1926-09-10 1927-10-20 Sidny Zillwood Milledge Improvements connected with exhaust systems of internal combustion engines
US1804070A (en) * 1929-04-16 1931-05-05 Sykes John Edward Exhaust silencer
GB341634A (en) * 1929-11-26 1931-01-22 William Joseph Wood Improvements in or relating to silencers for use with internal combustion engines
FR848965A (fr) * 1938-07-21 1939-11-09 Pare-flammes
US2270115A (en) * 1939-06-28 1942-01-13 Eliot Samuel Muffler for internal combustion engines
GB568140A (en) * 1943-09-06 1945-03-20 Jean Clement Daninos Improvements in devices for damping flames from the exhaust pipes of internal combustion engines
FR1158183A (fr) * 1956-08-07 1958-06-11 Dispositif dit <<silencieux>> à débit d'échappement réglable, pour véhicules àmoteurs à explosion
US4109750A (en) * 1977-05-24 1978-08-29 Lockheed Aircraft Corporation Zeno duct sound attenuating means

Also Published As

Publication number Publication date
DE2845902C2 (de) 1985-05-30
ATE1530T1 (de) 1982-09-15
WO1980000861A1 (fr) 1980-05-01
BR7908869A (pt) 1981-06-30
DE2845902A1 (de) 1980-04-24
JPS55500832A (fr) 1980-10-23
EP0020508A1 (fr) 1981-01-07
US4315560A (en) 1982-02-16

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