Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02730209 2011-01-04
WO 2010/004476 PCT/IB2009/052827
Title: Improved Sound-Attenuating Muffler Having Reduced Back Pressure
FIELD AND BACKGROUND OF THE INVENTION
The present invention relates to sound-attenuating mufflers for internal
combustion engines and, more particularly, to sound-attenuating mufflers
generating reduced back pressure.
Numerous muffler constructions have been proposed for the attenuation of
the sound component of an exhaust gas stream from an internal combustion
engine.
The present invention is an improvement to the low back-pressure sound-
attenuating mufflers of U.S. Patent Nos. 6,286,623 and 6,776,257 to the
present
inventor and incorporated herein by reference.
The low back-pressure sound-attenuating mufflers of U.S. Patent Nos.
6,286,623 an 6,776,257 are weft suitecFfor sports cars.
There is therefore a need for a low back-pressure sound-attenuating muffler
having a lower decibel output than the previous mufflers so as to be usable on
regular passenger vehicles.
SUMMARY OF THE INVENTION
The present invention is a low back-pressure sound-attenuating muffler
having a lower decibel output than the previous mufflers so as to be usable on
regular passenger vehicles.
CA 02730209 2011-01-04
WO 2010/004476 PCT/IB2009/052827
According to the teachings of the present invention there is provided, a
muffler for an internal combustion engine comprising: (a) a housing having an
inlet
end with an inlet opening formed for a flow of exhaust gases into the housing
and
an outlet end with an outlet opening formed for a discharge of exhaust gases
from
the housing; (b) a first chamber and a second chamber sequentially arranged
within
the housing; (c) a perforated pipe passing longitudinally through a central
region of
both the first and the second chambers such that the perforated pipe extends
partially into the first chamber, extends a full length of the second chamber;
wherein the perforations allow the exhaust gases to enter the perforated pipe
so as to
be directed through an interior of the perforated pipe and into the third
chamber and
a partition separating the first and the second chambers includes a hole that
enables
some of the exhaust gases to pass from the first chamber into the second
chamber
without passing through the central perforated pipe.
According to a further teaching of the present invention, the perforated pipe
as-a-di rnet that is-W5%-f-10% o-of---tie-diar e r of he lit opening:
According to a further teaching of the present invention, an upstream end of
the perforated pipe is partially sealed.
According to a further teaching of the present invention, an upstream end of
the perforated pipe is 60%-80% open.
According to a further teaching of the present invention, perforations in the
perforated pipe extending partially into the first chamber cover 25%-35% of
the
surface of the perforated pipe and, perforations in the perforated pipe
extending the
2
CA 02730209 2011-01-04
WO 2010/004476 PCT/IB2009/052827
full length of the second chamber cover 60%-75% of the surface of the
perforated
pipe.
According to a further teaching of the present invention, there is also
provided: (d) a third chamber containing a deflection element, the perforated
pipe
extending so as to open at its downstream end into a third chamber, thereby
directing the exhaust gases toward the deflection element; and (e) a fourth
chamber
configured to channel the flow of gas to the outlet opening.
According to a further teaching of the present invention, the deflection
element is a hollow pyramid having interior surfaces and exterior surfaces
joining at
a first end to form a pyramidal apex, the pyramidal apex pointing toward the
inlet
end of the muffler and extending at a second end to form an open base
interconnected to a partition separating the third and the fourth cambers.
According to a further teaching of the present invention, the deflection
element is a dome-shaped partition having an exterior surface, a first end of
the
- ex-tenor-sur-face-pointing ow-ar-d the inle-t-end-0f the-muff r; m&-widening-
out-at-a-
second end to form a base interconnected to a partition separating the third
and the
fourth cambers.
There is also provided according to the teachings of the present invention, a
muffler for an internal combustion engine comprising: (a) a housing having an
inlet
end with an inlet opening formed for a flow of exhaust gases into the housing
and
an outlet end with an outlet opening formed for a discharge of exhaust gases
from
the housing; (b) at least a first chamber, an intermediate and a last chamber
sequentially arranged within the housing, the intermediate chamber containing
a
3
CA 02730209 2011-01-04
WO 2010/004476 PCT/IB2009/052827
deflection element chosen from a group including: (i) a hollow pyramid; and
(ii) a
dome-shaped partition; (c) a pipe passing longitudinally through the first
chamber
so as to open at its downstream end into the intermediate chamber, thereby
directing
the exhaust gases toward the deflection element; and (d) a perforated pipe
extending
through the last chamber, the perforated pipe having an upstream opening into
the
intermediate chamber and configured to channel the exhaust gas to the outlet
opening.
According to a further teaching of the present invention, the pipe passes
longitudinally through an axially central region of the first chamber.
According to a further teaching of the present invention, a partition
separating the first and the intermediate chambers includes a hole that
enables some
of the exhaust gases to pass freely between the first chamber and the
intermediate
chamber.
According to a further teaching of the present invention, the first chamber
5- e-xtends-be-;w-ee-n-4-0%-85%-of-the total4eng -oftbe-housing:
According to a further teaching of the present invention, the last chamber
extends between 5%-80% of the total length of the housing.
According to a further teaching of the present invention, there is also
provided a sound-attenuating material deployed in at least one of the first
chamber,
the intermediate chamber and the last chamber.
According to a further teaching of the present invention, the sound-
attenuating material is configured from at least one chosen from the group
that
includes mineral fibers and synthetic fibers.
4
CA 02730209 2011-01-04
WO 2010/004476 PCT/IB2009/052827
According to a further teaching of the present invention, the hollow pyramid
deflection element has interior surfaces and exterior surfaces joining at a
first end to
form a pyramidal apex, the pyramidal apex pointing toward the inlet end of the
muffler and extending at a second end to form an open base interconnected to a
partition separating the intermediate and the last cambers.
According to a further teaching of the present invention, the dome-shaped
partition deflection element has an exterior surface, a first end of the
exterior
surface pointing toward the inlet end of the muffler, and widening out at a
second
end to form an open base interconnected to a partition separating the
intermediate
and the third cambers.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is herein described, by way of example only, with reference to
the accompanying drawings, wherein:
SIG-l-is-a-p-exspectie c-ut_o4)en-vievL-o tl e rr ffler o U.S Patent: No.
6,286,623;
FIG. 2 is a perspective, cut-open view of the muffler of U.S. Patent No.
6,776,257;
FIG. 3 is a perspective, cut-open view of a first preferred embodiment of a
muffler constructed and operational according to the teachings of the present
invention;
FIG. 4 is a perspective, cut-open view showing the flow path of exhaust
gases through the embodiment of FIG. 3;
5
CA 02730209 2011-01-04
WO 2010/004476 PCT/IB2009/052827
FIG. 5 is a perspective, cut-open view of a second preferred embodiment of a
muffler constructed and operational according to the teachings of the present
invention;
FIG. 6 is a perspective, cut-open view showing the flow path of exhaust
gases through the embodiment of FIG. 5;
FIG. 7 is a perspective, cut open view of a third preferred embodiment of a
muffler constructed and operational according to the teachings of the present
invention having a pyramidal deflection element; and
FIG. 8 is a perspective, cut-open view of a fourth preferred embodiment of a
muffler constructed and operational according to the teachings of the present
invention having a dome-shaped deflection element.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention is a low back-pressure sound-attenuating muffler
having-a-Io er__decib~l~utput~har~the pze~io a ffexs o as t4 be usable on
regular passenger vehicles.
The principles and operation of low back-pressure sound-attenuating muffler
according to the present invention may be better understood with reference to
the
drawings and the accompanying description.
By way of introduction reference is made to the prior art low back-pressure
sound-attenuating mufflers of V.S. Patent Nos. 6,286,623 and 6,776,257 to the
present inventor and incorporated herein by reference.
6
CA 02730209 2011-01-04
WO 2010/004476 PCT/IB2009/052827
it should be noted that as used herein, references to sequence such as first,
intermediate and last refer to the relationship of elements in the drawings
and are
not intended to limit the scope of the present invention.
Figure 1 shows a cut open view of the muffler 200 of U.S. Patent No.
6,286,623. The muffler 200 consists of an elongated housing 202 having an
inlet
206 for introducing the exhaust gases, an outlet 208 for discharging the
exhaust
gases, a pyramidal partition 250 and converging partitions 240 and 260.
The exhaust gases from the internal combustion engine are introduced into
the muffler 200 through the inlet 206. The exhaust gases enter the housing 202
and
flow longitudinally through the length of muffler 200 passing first through
chamber
212. The exhaust gases exit chamber 212 through an opening in partition 240.
Partition 240 is shaped like a funnel (or truncated pyramid), disposed such
that the
opening in the partition 240 centers the flow of exhaust gases within housing
202.
The flow exhaust gases then enters the second chamber 214 and encounters the
apex
1-5 230-of-pyrarni-dal partition Z-5O; causing-t-he-Howto-lie-dofleeted-alo g
he xt iDr
faces of pyramidal partition 250 and towards the interior surface of the outer
wall of
housing 202.
The exhaust gases flow through the four spaces 252 formed by the rugose
base of the pyramidal partition 250. A substantial first portion of the
exhaust gases
continue to flow in the direction of the outlet pipe 208, thereby creating a
low
pressure region inside the pyramidal partition 250. Consequently, a second
portion
of the exhaust gases changes direction and enters (is drawn into) the inside
region of
pyramidal partition 250 before continuing toward the outlet pipe 208. The
exhaust
7
CA 02730209 2011-01-04
WO 2010/004476 PCT/IB2009/052827
gases flow through converging partition 260, which is substantially identical
in
shape and in disposition to converging partition 240. Thus, the flow of
exhaust
gases enters the third chamber 216 and is again centered within the housing
202 by
the partition outlet 224 before being discharged through outlet pipe 208.
Figure 2 shows a perspective, cut-open view of the muffler 300 of U.S.
Patent No. 6,776,257. Muffler 300 includes an elongated housing 302 having an
inlet 306 for introducing the exhaust gases, an outlet 308 for discharging the
exhaust gases, a main partition 350, and an aligning partition 340.
The exhaust gases from the internal combustion engine are introduced
through the inlet 306. The exhaust gases enter housing 302 and flow
longitudinally
through the length of muffler 300 passing first through chamber 312. The
exhaust
gases exit chamber 312 through an opening in partition 340. Partition 340 is
preferably shaped like a funnel (or truncated pyramid), and most importantly,
is
disposed such that the exhaust gas flow is centered within the housing 302 as
the
ex-haunt aces-enter th,e~--see-ond-chamber 314-and-floe-how of--exact-gases-
encounters the top of domed partition 350, causing the flow to be deflected
along
the exterior face of domed partition 350.
The exhaust gases flow through openings 352 in the sides of domed partition
350 Openings 352 are preferably disposed on opposite sides of domed partition
350.
Subsequently, the exhaust gases continue to flow in the direction of outlet
pipe 308, thereby creating a low pressure region inside domed partition 350.
Consequently, a portion of the exhaust gases change direction and enter (are
drawn
into) the inside of domed partition 350 before continuing in the direction of
outlet
8
CA 02730209 2011-01-04
WO 2010/004476 PCT/IB2009/052827
pipe 308. The exhaust gases flow through converging partition 360, which is
advantageously similar in shape and in disposition to converging partition
340, and
enter the third chamber 316 before being discharged through outlet pipe 308.
Generally speaking, the embodiments of U.S. Patent Nos. 6,286,623 and
6,776,257 as briefly described above include an inlet chamber, a deflection
chamber
in which a deflection element is deployed and an outlet chamber.
The first to preferred embodiments of the present invention relate to an
improvement that may be used to benefit both of the previous muffler
embodiments
described above. Specifically, the present invention includes an improved
inlet
configuration having first and second sequential chambers with a perforated
central
pipe passing longitudinally through a central region of both chambers for
directing
the exhaust gases into the third chamber in which the deflection element is
deployed. Additionally, the partition separating the first and second chamber
has a
hole that enables some of the gas to pass from the first chamber into the
second
5 chamber et thr-ough-theme-entr-al-pipe.
Described below are two exemplary embodiments of the present invention
The first preferred embodiment of Figures 3 and 4 relates to a muffler
combining
the features of the present invention with the pyramidal partition deflection
element
of U.S. Patent No. 6,286,623. The second preferred embodiment of Figures 5 and
6
relates to a muffler combining the features of the present invention with the
domed
partition deflection element of U.S. Patent No. 6,776,257
Referring now to the drawings, Figures 3 and 4 illustrate a muffler 2
generally defined by a housing 4. An inlet 6 is provided in the inlet end of
the
9
CA 02730209 2011-01-04
WO 2010/004476 PCT/IB2009/052827
muffler for introducing exhaust gases into the first chamber 10. The improved
inlet
configuration has the first chamber 10 and a second chamber 12 sequentially
arranged within muffler 2. A perforated pipe 20, with its upstream end 22
partially
sealed, passing longitudinally through a central region of both the first 10
and the
second 12 chambers such that perforated pipe 20 extends partially into the
first
chamber 10 and extends the full length of the second chamber 12. Perforated
pipe
20 extends at its downstream end 24 through partition 40 and opens into the
third
chamber 14. The perforations 26a allow the exhaust gases to enter the
perforated
pipe 20 from the first chamber 10, while perforations 26b allow the exhaust
gases to
enter the perforated pipe 20 from the second chamber 12. Once the exhaust
gases
enter perforated pipe 20 they are directed through the interior of perforated
pipe 20
and into the third chamber 14. As illustrated here, the perforations 26 are
formed
over a predetermined percentage of the surface of pipe 20.
The partition 30 separating the first and second chambers includes a
I -preferably round-hole-3-2 that-enables-semo--ef-the-gas-to pass-rem-
thefirst-chambe
10 into the second chamber 12 without passing through the central perforated
pipe
20. Exhaust gases that enter the second chamber 12 then pass through the
perforations 26 in the section of perforated pipe 20 deployed in second
chamber 12.
It will be appreciated that hole 32 may be of substantially any suitable size
and
shape.
With this basic understanding of the general structure of the first two
chambers of the muffler, it will be appreciated that inlet 6 is configured for
attachment to the exhaust pipe of the vehicle on which the muffler is deployed
and
CA 02730209 2011-01-04
WO 2010/004476 PCT/IB2009/052827
therefore may vary in diameter depending on the specifications of the of the
vehicle
manufacturer. It will be appreciated that inlet 6 may be configured as more
that one
inlet pipe. It will be readily understood that in such an embodiment, the
percentages
listed herebelow are applied to the combined size of all inlet pipes.
Similarly, the
outlet pipe 8 may be configured as more that one outlet pipe and the
percentages
listed herebelow are applied to the combined size of all outlet pipes.
In order for the muffler of the present invention to perform at an optimum
level, perforated pipe 20 has a diameter that is 100%-130% of the diameter of
inlet
pipe 6. It will be appreciated that perforated pipe 20 may be implemented as
more
than one perforated pipe as long as the ratio of 100%-130% of the diameter of
inlet
pipe 6 is maintained. The upstream end 22 of the perforated pipe 20 is
partially
sealed so as to be 60%-80% open. The perforation holes in the perforated pipe
20
may range from 15mm-S5mm in diameter. Perforations 26a cover between 20%-
40% of the surface of perforated pipe 20, while perforations 26b cover 50%-90%
of
i 5--tZe-&urface of perforated pipe 20.- 4ole 2-configured-in partit:ion-30-
has a-dia ter
that is 60%-80% of the diameter of perforated pipe 20. It will be appreciated
that
hole 32 may be implemented as a plurality of holes configured in partition 30,
however, the combined size of the opening still falls within the range of 60%-
80%
of the diameter of perforated pipe 20. Further, embodiments in which the
second
chamber 12 is subdivided into a number of chambers through which perforated
pipe
20 passes are within the scope of the present invention. It should be noted
that these
specifications apply to the embodiment of the present invention described
bellow
11
CA 02730209 2011-01-04
WO 2010/004476 PCT/IB2009/052827
with regard to Figures 5 and 6, as well as any muffler constructed and
operational
according to the teachings of the present invention.
Similar to the muffler of Figure 1, the flow of exhaust gases is centered
within the housing 4 as the exhaust gases leaves the downstream end 24 of the
perforated pipe 20, enters the third chamber 14. The flow of exhaust gases
encounters the apex of pyramidal partition 50, which is spaced a distance of
20mm
60mm from the downstream end 24 of the perforated pipe 20, causing the flow to
be
deflected along the exterior faces of pyramidal partition 50 and towards the
interior
surface of the outer wall of housing 4.
The exhaust gases flow then through the four spaces 52 formed by the rugose
base of the pyramidal partition 50. A substantial first portion of the exhaust
gases
continue to flow in the direction of the outlet pipe 120, thereby creating a
low
pressure region inside the pyramidal partition 150. Consequently, a second
portion
of the exhaust gases changes direction and enters (is drawn into) the inside
region of
pyramidal-partition a0-befor"ont-inuing~-ow,ard-the-outlet-pipe 8 Thhee aus
gases-
flow through partition 60 and is again centered within the housing 100 as the
exhaust gases enter the fourth chamber 16 before being discharged through
outlet
pipe 8, formed in the outlet end of the muffler.
The arrows in Figure 4 illustrate the flow path of the exhaust gases through
this embodiment of the muffler of the present invention.
Figures 5 and 6 illustrate a muffler 102 generally defined by a housing 4,
which includes an inlet configuration similar to the embodiment of Figures 3
and 4,
therefore, the same reference numerals are used here to refer to corresponding
12
CA 02730209 2011-01-04
WO 2010/004476 PCT/IB2009/052827
components. It will be appreciated that the specifications relating to
component size
detailed above apply equally here as well.
An inlet 6 is provided in the inlet end of the muffler for introducing exhaust
gases into the first chamber 10. The improved inlet configuration of this
embodiment also has the first chamber 10 and a second chamber 12 sequentially
arranged within muffler 102. A perforated pipe 20, with its upstream end 22
sealed,
passing longitudinally through a central region of both the first 10 and the
second
12 chambers such that perforated pipe 20 extends partially into the first
chamber 10
and extends the full length of the second chamber 12. Perforated pipe 20
extends at
its downstream end 24 through partition 40 and opens into the third chamber
14.
The perforations 26 allow the exhaust gases to enter the perforated pipe 20 so
as to
be directed through the interior of perforated pipe 20 and into the third
chamber 14.
The partition 30 separating the first and second chambers includes a
preferably round hole 32 that enables some of the gas to pass from the first
chamber
1 5-10-into the-se wnd-chamber T-2-ithout p- as ing-through-the-centr-al-per-
for-atzdpipe-
20. Exhaust gases that enter the second chamber 12 then pass through the
perforations 26 in the section of perforated pipe 20 deployed in second
chamber 12.
It will be appreciated that in this embodiment as well, hole 32 may be of
substantially any suitable size and shape.
Similar to the muffler of Figure 2, the exhaust gas flow is centered within
the
housing 4 as the exhaust gases leaves the downstream end 24 of the perforated
pipe
20, and enters the third chamber 14 and the flow of exhaust gases encounters
the top
of domed partition 150, causing the flow of exhaust gases to be deflected
along the
13
CA 02730209 2011-01-04
WO 2010/004476 PCT/IB2009/052827
exterior face of domed partition 150. Dome-shaped partition 150 having an
exterior
surface, a first end of the exterior surface points toward the inlet end of
the muffler,
and widening out at a second end to form a base, said dome-shaped partition
having
at least two partition openings disposed between said first end and said
second end
of said exterior surface
The exhaust gases flow through openings 152 in the sides of domed partition
150. Openings 152 are preferably disposed on opposite sides of domed partition
150.
Subsequently, the exhaust gases continue to flow in the direction of outlet
pipe 8 formed in the outlet end of the muffler, thereby creating a low
pressure
region inside domed partition 150. Consequently, a portion of the exhaust
gases
change direction and enter (are drawn into) the inside of domed partition 150
before
continuing in the direction of outlet pipe 8. The exhaust gases flow through
an
opening (not shown) partition 160, and enter the fourth chamber 16 before
being
-15 disc-harmed--thr-ough-outlet-pipe-S:
The arrows in Figure 6 illustrate the flow path of the exhaust gases through
this embodiment of the muffler of the present invention.
The embodiment of Figure 7 relates to a third preferred embodiment 400 of
the muffler combining features of the present invention with the pyramidal
partition
deflection element of U.S. Patent No. 6,286,623.
Figure 7 illustrates muffler 400 of the present invention generally defined by
a housing 401 and end walls 402 and 406. An inlet 408 for introducing exhaust
gases into the muffler 400 is provided in end wall 402. The inlet
configuration. of
14
CA 02730209 2011-01-04
WO 2010/004476 PCT/IB2009/052827
the mufflers of the present invention includes an inlet pipe 409 that is
axially
centered within the housing 401 and extends from the inlet 408 through the
first
chamber 403 and opens at its downstream end into the intermediate chamber 417
sequentially arranged within muffler 400.
As the flow of exhaust gases leaves the downstream end of pipe 409 and
enters the intermediate chamber 417, the flow of exhaust gases encounters the
apex
of pyramidal deflection element 410 causing the flow to be deflected along the
exterior faces of pyramidal deflection element 410 and towards the interior
surface
of the outer wall of housing 401. It will be appreciated that although pipe
409 and
the apex of pyramidal deflection element 410 are illustrated herein as
substantially
axially centered within the housing 401, it is within the scope of the present
invention to provide a non-straight pipe that extends from an inlet that is
not axially
centered within the housing 401 to a downstream end that is aligned with the
apex
of pyramidal deflection element 410, which need not be axially centered within
the
Sousing-404:
Opening 413 configured in interior partition wall 404 allows exhaust gasses
to enter the first chamber 403 and thereby alleviate some excess pressure that
may
from in the intermediate chamber 417. It will be appreciated that interior
partition
wall 404 may be configured with a single opening 413 as illustrated herein, or
with
a plurality of opening to allow passage of exhaust gasses between the first
403 and
intermediate 417 chambers.
The exhaust gases then flow through the four spaces 418 formed at the base
of the pyramidal deflection element 410. A substantial first portion of the
exhaust
CA 02730209 2011-01-04
WO 2010/004476 PCT/IB2009/052827
gases continue to flow in the direction of the opening 414 to the perforated
pipe
411, thereby creating a low pressure region inside the pyramidal deflection
element
410. Consequently, a second portion of the exhaust gases changes direction and
enters (is drawn into) the inside region of pyramidal deflection element 410
before
continuing toward opening 414. The flow pattern thus created serves to
decrease the
sounds associated with the exhaust.
Perforated pipe 411 extends from opening 414 through the last chamber 407
to the outlet pipe 412. As the exhaust gases flow through perforated pipe 411,
the
associated sound waves pass freely through the perforations 416 into the last
chamber 407 and are thereby further dissipated. Preferably, as illustrated
herein, the
last chamber 407 contains a sound-attenuating material made from mineral
fibers or
synthetic fibers either individually or in combination. Such fibers include,
but are
not limited to, Asbestos fibers, basalt fibers, mineral wool, glass wool,
metal wools
such as steel wool and bronze wool, carbon fiber and aramid fiber such as
Kevlaro.
-1-5 T-he-embodiment-of figure- Vr-efates-t~~s cond-pr-e-fe dembodlment-50Q
of the muffler combining the features of the present invention with the dome-
shaped
deflection element of U.S. Patent No. 6,776,257. Muffler 500 is generally
defined
by a housing 501 and end walls 502 and 506. An inlet 508 for introducing
exhaust
gases into the muffler 500 is provided in end wall 502. The inlet
configuration of
the mufflers of the present invention includes an inlet pipe 509 that is
axially
centered within the housing 501 and extends from the inlet 508 through the
first
chamber 503 and opens at its downstream end into the intermediate chamber 517
sequentially arranged within muffler 500.
16
CA 02730209 2011-01-04
WO 2010/004476 PCT/IB2009/052827
As the flow of exhaust gases leaves the downstream end of pipe 509 and
enters the intermediate chamber 517, the flow of exhaust gases encounters the
top
of the dome-shaped deflection element 520, causing the flow of exhaust gases
to be
deflected along the exterior face of dome-shaped deflection element 520. Dome-
shaped deflection element 520 has an exterior surface, a first end of the
exterior
surface points toward the inlet end of the muffler and widens out at a second
end to
form a base. The dome-shaped deflection element also has at least two
partition
openings 522 disposed between the first end and the second end preferably
formed
at the base end_ The exhaust gases flow through openings 522 in the sides of
dome-
shaped deflection element 520. Openings 522 are preferably disposed on
opposite
sides of dome-shaped deflection element 520.
It will be appreciated that although pipe 509 and the dome-shaped deflection
element 520 are illustrated herein as substantially axially centered within
the
housing 501, here too, it is within the scope of the present invention to
provide a
3 n on-straight-pipet-iat-extends from -an inlet-the-is-riot ax4ally c nt-e-r-
ed-withi;t-~--th
housing 501 to a downstream end that is aligned with the apex of dome-shaped
deflection element 520, which need not be axially centered within the housing
501.
As discussed above, here too, opening 513 configured in interior partition
wall 504 allows exhaust gasses to enter the first chamber 503 and thereby
alleviate
some excess pressure that may from in the intermediate chamber 517. It will be
appreciated that in this embodiment as well, interior partition wall 504 may
be
configured with a single opening 513 as illustrated herein, or with a
plurality of
17
CA 02730209 2011-01-04
WO 2010/004476 PCT/IB2009/052827
opening to allow passage of exhaust gasses between the first 503 and
intermediate
517 chambers.
As the exhaust gases flow through the openings 522 formed at the base of the
dome-shaped deflection element 520, a substantial first portion of the exhaust
gases
continue to flow in the direction of the opening 514 to the perforated pipe
511,
thereby creating a low pressure region inside the dome-shaped deflection
element
510. Consequently, a second portion of the exhaust gases changes direction and
enters (is drawn into) the inside region of dome-shaped deflection element 510
before continuing toward opening 514. Here too, the flow pattern thus created
serves to decrease the sounds associated with the exhaust.
Perforated pipe 511 extends from opening 514 through the last chamber 507
to the outlet pipe 512. As the exhaust gases flow through perforated pipe 511,
the
associated sound waves pass freely through the perforations 516 into the last
chamber 507 and are thereby further dissipated. Preferably, as illustrated
herein, the
1 S--las"hamber 50-7~ontai s ound-attenuating-material-made from mineral-
fibers-or
synthetic fibers either individually or in combination, as mentioned above.
With this basic understanding of the general structure of the preferred
embodiments 400 and 500 of the muffler of the present invention, it will be
appreciated that inlets 408 and 508 are configured for attachment to the
exhaust
pipe of the vehicle on which the muffler is deployed and therefore may vary in
diameter depending on the specifications of the of the vehicle manufacturer.
It will
be appreciated that inlets 408 and 508 may be configured as two or more inlet
pipes
409 and 509 that come together and have a single downstream end that is
aligned
18
CA 02730209 2011-01-04
WO 2010/004476 PCT/IB2009/052827
with the apex of the deflection element. Similarly, the outlet pipes 412 and
512 may
be configured as more than one outlet pipe.
It should be noted that the first chamber 403 and 503 may extend for a
distance of 10%-85% of the total length of the muffler 400 and 500. Further,
the
first chamber may be configured as more than one chamber.
Similarly, the last chamber 407 and 507 may extend for a distance of 5%-
80% of the total length of the muffler 400 and 500, and the last chamber may
be
configured as more than one chamber.
Further, although the sound-attenuating material 415 and 515 is illustrated
herein as being deployed in the last chamber 407 and 507, it will be
appreciated that
sound deadening material may be deployed in any of the first 403 and 503,
intermediate 417 and 517 and last 407 and 507 chambers either individually or
in
combination. Also, the sound-attenuating material may deployed so as to
partially
fill or fully fill the chamber in which it is deployed.
It will be appreciated that the above descriptions are intended only to serve
as examples and that many other embodiments are possible within the spirit and
the
scope of the present invention.
19
