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EP 0 879 937 A1 |
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EUROPEAN PATENT APPLICATION |
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Date of publication: |
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25.11.1998 Bulletin 1998/48 |
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Date of filing: 21.05.1997 |
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International Patent Classification (IPC)6: F01N 1/10 |
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Designated Contracting States: |
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AT BE CH DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE |
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Designated Extension States: |
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AL LT LV RO SI |
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Applicant: F.lli Bastelli snc di Bastelli Paolo - Bastelli Claudio & C. |
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40127 Bologna (IT) |
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Inventor: |
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- Bastelli, Claudio
40127 Bologna (IT)
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Representative: Sassatelli, Franco T., Dr. |
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c/o INIP
5, via Ruggi 40137 Bologna 40137 Bologna (IT) |
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Silencer group for muffler of internal combustion engines |
(57) The group is formed by a pipe (1) obstructed in the middle by a separator (2) to
form two equal expansion openings (3 and 4) with diffusion holes (5). Through said
holea (5) the coming in flow of the exhaust-gases passes from the first expansion
opening (3) to an outside chamber (6) of a coaxial cilindrical body with closed ends
and provided in its outside of a coating (8) in steel wool and long fiber rock wool.
From said outside chamber (6) of the cilindrical body (7) the flow of the exhaust-gases,
through the other diffusion holes (5), comes in getting out into the second diffusion
opening (4).
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[0001] The invention refers to a silencer group for dropping of sounds for muffler of internal
combustion engines. Said group enormously comes to raise the yield by a considerable
increase of the diffusion effect of the exhaust-gas on the absorption walls. Said
increase permits using two subsequent expansion openings between which a compression
of the same gases is permitted. For the dropping of the sounds the current mufflers
act on the base of two systems: a reflection system consists of a set of inside bulkheads
with separators to determine a circuit and/or sound absorption parts to drop sounds;
and an absorption system in which the exhaust-gases pass trought a dropping chamber
to be equipped with sound absorption barriers. Of two said systems, the reflection
system is affected to counterpression effects caused by the flow narrowing provided
to the exhaust, while the absorption system permits a small dropping of the sounds
such as the contact of the flow of the exhaust-gases with the sound absorption barriers
is highly reduced during the use for the clogging of the circuit holes. The above
cited problems are resolved by the invented silencer group which permits to realize
mufflers using one or more of said silencer groups for dropping the sounds to be assembled
in working succession so permitting to put in connection their yield with the different
using necessities. The invented group is formed by a pipe 1 obstructed in the middle
to a separator 2 to form two equal expansion openings 3 and 4 with diffusion holes
5. Through said holes 5 the coming in flow of the exhaust-gases passes from the first
expansion opening 3 to an outside chamber 6 of a coaxial cilindrical body with closed
ends and provided in its outside of a coating 8 in steel wool and long fiber rock
wool. From said chamber 6 of the cilindrical body 7 the flow of the exhaust-gases
through the other diffusion holes 5 comes in getting out into the second diffusion
opening 4. In the embodiment with an only one silencer group for dropping the sounds,
the flow of the exhaust-gases through an inlet 9 comes into the first expansion opening
3. Then, through the diffusion holes 5, said flow comes into a chamber 6 where a high
dropping is determined due to the coating 8 of the cilindrical body 7 and to the wrapped
up sound absorption wadding 10. At the end, the flow through the other diffusion holes
5 comes into the second expansion opening 4 and goes out through the outlet 11. In
the embodiment with a muffler with two silencer groups for dropping the sounds, the
flow of the exhaust-gases through an inlet 12 comes into a distribution chamber 13.
In said chamber a flow division is determined with passage through two mouths 9 letting
into the circuits of the silencer gropus. At the end the flows come through the inlets
11 of the same groups into the mixing chamber 14 to go out through a channel 15. The
silencer group and different embodiments are illustrated in the drawings of sheets
1 and 2. In sheet 1 fig. 1 is longitudinal section view of a silencer group for dropping
sounds for muffler of internal combustion engines. Fig. 2 is longitudinal section
view of a muffler providing only one silencer group. Fig. 3 is a sectional view taken
along the line A-A' of the silencer group. Fig. 4 is a sectional view taken along
the line A-A' pf the muffler to show its circular shape. Fig. 5 is a sectional view
taken along the line A-A' of a muffler using a group for the dropping of the sounds
but with elliptic shape. In sheet 2 fig. 6 is longitudinal section view of a muffler
using a couple of the invented groups to show the different circuits for dropping
the sounds between the distribution chamber 13 and the mixing chamber 14. Fig. 7 is
a sectional view taken along the line B-B' to show a muffler with a couple of silencer
groups with elliptic shape. Fig. 8 is a sectional view taken along the line B-B' of
a muffler with a couple of silencer groups with circular shape.
1. Silencer group for muffler of internal combustion engines consists of a pipe (1) obstructed
in the middle to a separator (2) to form two equal expansion openings (3 and 4) with
diffusion holes (5), characterized in that through said holes (5) the coming in flow
of the exhaust-gases passes from the first expansion opening (3) to an outside chamber
(6) of a coaxial cilindrical body with closed ends and provided in its outside of
a coating (8) in steel wool and long fiber rock wool, and in that from said outside
chamber (6) of the cilindrical body (7) the flow of the exhaust-gases through the
other diffusion holes (5) comes in getting out into the second diffusion opening (4).
2. Silencer group for muffler of internal combustion engines, as per claim 1), characterized
in that providing a muffler with an only one silencer group for dropping the sounds,
the flow of the exhaust-gases through an inlet (9) comes into the first expansion
opening (3) and, through the diffusion holes (5), it comes into a chamber (6) where
a high dropping is determined due to the coating (8) of the cilindrical body (7) and
to the wrapped up sound absorption wadding (10); then the flow through the other diffusion
holes (5) comes into the second expansion opening (4) and goes out through the outlet
(11).
3. Silencer group for muffler of internal combustion engines, as per claim 1), characterized
in that providing a muffler with two silencer groups for dropping the sounds, the
flow of the exhaust-gases through an inlet (12) comes into a distribution chamber
(13) where the flow division is determined with passage through two mouths (9) letting
into the circuits of the silencer groups; then the flows come through the inlets (11)
of the same groups into the mixing chamber (14) to go out through a channel (15).

