CH624733A5

CH624733A5 - Silencer for flowing gases, especially exhaust gases of internal combustion engines for vehicles

Info

Publication number: CH624733A5
Application number: CH1379477A
Authority: CH
Inventors: Walter Bauerschmidt; Rudolf Buhmann
Original assignee: Eberspaecher J Fa
Priority date: 1977-03-15
Filing date: 1977-11-11
Publication date: 1981-08-14
Also published as: DE2711191A1; IT1088751B; ATA908577A; DE2711191C2; FR2384105A1; AT363735B

Description

Die Erfindung wird nun anhand der Zeichnung mit einem Ausführungsbeispiel näher erläutert; dabei zeigt The invention will now be explained in more detail with reference to the drawing using an exemplary embodiment; shows

Fig. 1 den erfindungsgemässen Schalldämpfer im Längsschnitt, 1 shows the silencer according to the invention in longitudinal section,

Fig. 2 in einem Querschnitt gemäss der Linie A-B und Fig. 2 in a cross section along the line A-B and

Fig. 3 in einem Querschnitt gemäss der Linie C-D in Fig. 1. 3 in a cross section along the line C-D in Fig. 1st

Der erfindungsgemässe Schalldämpfer weist im dargestellten Ausführungsbeispiel nach den Figuren 1 und 2 ein an den Stirnseiten verschlossenes rohrförmiges Gehäuse 1 mit zwei Eintrittsrohren 2a und 2b sowie einem Austrittsstutzen 3 auf. Die Eintrittsrohre sind in einer Querebene des Gehäuses in einem Winkel von 90° zueinander angeordnet und stossen mit einer 45 ° -Gehrung unter Zwischenlage eines Blechstückes 4 aneinander an, das an der Innenwand der am einen Ende des Gehäuses liegenden Eintrittskammer 5 einseitig befestigt ist. Am anderen Ende des Gehäuses liegt eine Pufferkammer 6 mit Aufprallströmung, die mit der Eintrittskammer über ein Rohr 7 in Verbindung steht. An diese Pufferkammer schliesst eine zweite Pufferkammer 10 mit Aufprallströmung an, die über ein weiteres, nämlich kürzeres, die Austrittskammer 9 ebenfalls durchdringendes Rohr 11 mit der Eintrittskammer in Verbindung steht. Die beiden Verbindungsrohre weisen im stromabwärts, dem Austrittsstutzen 3 entgegengesetzten Bereich eine Perforation 8 bzw. 12 auf; diese Perforationen liegen innerhalb einer durchströmten Resonanzkammer 14, die von der die zweite Pufferkammer 10 nach innen zu begrenzenden Querwand 13 und von einer zwischen dieser und dem Bereich des Austrittsstutzens 3 angeordneten perforierten Querwand 15 gebildet wird, die beide von den Verbindungsrohren durchdrungen werden. In the exemplary embodiment shown in FIGS. 1 and 2, the silencer according to the invention has a tubular housing 1 which is closed at the end faces and has two inlet pipes 2a and 2b and an outlet connection 3. The inlet pipes are arranged in a transverse plane of the housing at an angle of 90 ° to one another and abut against one another with a 45 ° miter with the interposition of a piece of sheet metal 4 which is fastened on one side to the inner wall of the inlet chamber 5 located at one end of the housing. At the other end of the housing is a buffer chamber 6 with impact flow, which is connected to the inlet chamber via a pipe 7. Connected to this buffer chamber is a second buffer chamber 10 with an impact flow, which is connected to the inlet chamber via a further, namely shorter, tube 11, which also penetrates the outlet chamber 9. The two connecting pipes have a perforation 8 or 12 in the region downstream, opposite the outlet connection 3; these perforations lie within a flow-through resonance chamber 14, which is formed by the transverse wall 13 to be bounded inwardly by the second buffer chamber 10 and by a perforated transverse wall 15 arranged between the latter and the region of the outlet connector 3, both of which are penetrated by the connecting pipes.

Die Wirkungsweise des Schalldämpfers ist folgendermassen: The silencer works as follows:

Die Abgase gelangen durch die beiden Eintrittsrohre 2a und 2b über deren Perforation in die Eintrittskammer 5, wo sie sich ausdehen und vermischen. Sie strömen dann über die beiden parallelgeschalteten Verbindungsrohre 7 und 11 in je eine Pufferkammer 6 bzw. 10, wo sie eine Aufprallströmung The exhaust gases pass through the two inlet pipes 2a and 2b via their perforations into the inlet chamber 5, where they expand and mix. They then flow over the two parallel connecting pipes 7 and 11 into a buffer chamber 6 and 10, respectively, where they have an impact flow

5 5

10 10th

15 15

20 20th

25 25th

30 30th

35 35

40 40

45 45

50 50

55 55

60 60

65 65

3 624 733 3,624,733

erleiden. Durch die Perforation 8 bzw. 12 treten sie hierauf in sje durch die perforierte Querwand 15 in die Austrittskammer die gemeinsame Resonanzkammer 14 ein. Von hier strömen 9 und durch den Austrittsstutzen 3 ab. suffer. Through perforations 8 and 12, they enter the common resonance chamber 14 through the perforated transverse wall 15 into the exit chamber. From here flow 9 and through the outlet 3.

B B

1 Blatt Zeichnungen 1 sheet of drawings

Claims

624 733

1.Muffler for flowing gases, in particular exhaust gases from internal combustion engines for vehicles, especially commercial vehicles, with a tubular housing which has an inlet chamber at one end with a projecting inlet pipe which is perforated in its end region and closed at the end, at the other end a buffer chamber with impact flow and contains an outlet chamber with an outlet connection between these chambers and in which the inlet chamber is connected to the buffer chamber via a pipe which penetrates the outlet chamber and is perforated in some areas and is open at both ends, characterized in that between the outlet chamber (9) and the buffer chamber (6) a second buffer chamber (10) with an impact flow is arranged, which with the inlet chamber (5) via another, namely shorter, penetrating the outlet chamber, in the section facing the buffer chamber (10) perforated, open at both ends (11 ) is connected.

2. Muffler according to claim 1, characterized in that the connecting pipes (7, 11) of the inlet chamber (5) with the buffer chambers (6, 10) have perforations (8, 12) only in the downstream region, and that the outlet nozzle ( 3) is arranged in the opposite area of the outlet chamber (9).

2nd

PATENT CLAIMS

3. Muffler according to claim 1 or 2, characterized in that the mutually facing peripheral regions of the connecting pipes (7, 11) are kept free of perforation.

4. Silencer according to claim 2 or 3, characterized in that between a the second buffer chamber (10) to be limited inwardly transverse wall (13) and the area of the outlet nozzle (3) a perforated by the two connecting tubes (7, 11) perforated transverse wall (15) is arranged, and that the connecting pipes are perforated only in the region of the chamber (14) formed between these two transverse walls, so that it becomes a resonance chamber through which the two connecting pipes flow.

5. Muffler according to one of the preceding claims for internal combustion engines with two exhaust pipes, characterized in that the inlet chamber (5) has two projecting, at least in its end region perforated, frontally closed inlet pipes (2a, 2b).

6. Silencer according to claim 5, characterized in that the inlet pipes (2a, 2b) are arranged in a transverse plane of the housing (1) at an angle of approximately 90 ° to one another and with a miter corresponding to half the intermediate angle with the interposition of a piece of sheet metal (4th ) abut against each other, which is fixed on one side to the inner wall of the inlet chamber (5).

The application relates to a silencer according to the preamble of claim 1, which is based on DE-Gbn document 6 812 403. Such a known silencer usually meets the requirements with regard to good sound damping, low flow resistance, that is to say low engine back pressure, simple manufacture and good installation options. For higher demands, however, the range of damped sound frequencies in the known silencer is too small.

It is therefore an object of the invention to expand this range without impairing the other properties of the muffler mentioned above.

This object is achieved in an advanced manner with the characterizing features of claim 1. Because without significant extension of the muffler housing, an additional, parallel resonance path with its own buffer chamber with impact flow is obtained if the actual outlet chamber is reduced in size. The connecting channels in the two resonance paths are advantageously of different lengths, as a result of which a large bandwidth of the damped sound frequencies is achieved.

This effect is particularly enhanced by the feature mentioned in claim 2; the direct gas flow from the connecting pipes radially outwards into the outlet connection is prevented and the impact flow in the two buffer chambers is intensified. These effects are supported by the feature of claim 3.

By means of the measure specified in claim 4, a resonance chamber which is flowed through jointly from both connecting pipes is formed in a structurally quite simple manner and extends the sound-absorbing effect.

Claim 5 indicates the use of the muffler according to the invention for internal combustion engines with two exhaust pipes. As a result of the claimed measure, a merging downpipe that has been largely used up to now is superfluous; the installation conditions are also improved. The muffler according to the invention also avoids the arrangement of two mufflers connected in parallel, which is also very often complex and prone to malfunction, in which the required attachment of the respective outlet connections on the same side is quite difficult.

Claim 6 finally specifies a very simple holder for the gas inlet tubes, which deflects the gas flow in the direction of the perforation.