U.S. patent application number 11/118256 was filed with the patent office on 2006-11-02 for muffler with improved heat dissipation.
This patent application is currently assigned to Samson Motorcycle Products, Inc.. Invention is credited to Kenneth E. Price.
Application Number | 20060243521 11/118256 |
Document ID | / |
Family ID | 37233351 |
Filed Date | 2006-11-02 |
United States Patent
Application |
20060243521 |
Kind Code |
A1 |
Price; Kenneth E. |
November 2, 2006 |
Muffler with improved heat dissipation
Abstract
A muffler has inner and outer elongated concentric and radially
spaced generally cylindrical casings having inlet and outlet ends,
and providing an annular chamber therebetween. The outer casing has
an inlet opening into the annular chamber adjacent the inlet end of
the outer casing so that air may flow to the outer end. The inner
casing has an aperture adjacent the outlet end for the air to flow
from the annular chamber into the inner casing for discharge with
the exhaust. This air flow through the annular chamber reduces the
temperature of the outer casing from that of the inner casing.
Baffles are provided in the inner casing, and insulating material
may also be provided in the inner casing.
Inventors: |
Price; Kenneth E.; (Yorba
Linda, CA) |
Correspondence
Address: |
PEPE & HAZARD, LLP
225 ASYLUM ST.
HARTFORD
CT
06103
US
|
Assignee: |
Samson Motorcycle Products,
Inc.
|
Family ID: |
37233351 |
Appl. No.: |
11/118256 |
Filed: |
April 29, 2005 |
Current U.S.
Class: |
181/248 ;
181/247 |
Current CPC
Class: |
F01N 1/083 20130101;
F01N 1/24 20130101; F01N 2470/02 20130101; F01N 2260/022 20130101;
F01N 1/08 20130101; F01N 2270/02 20130101; F01N 2470/24
20130101 |
Class at
Publication: |
181/248 ;
181/247 |
International
Class: |
F01N 7/08 20060101
F01N007/08; F01N 1/00 20060101 F01N001/00 |
Claims
1. A muffler and exhaust extractor comprising: (a) an inner
elongated generally cylindrical casing having inlet and outlet
ends; (b) an outer elongated generally cylindrical casing having
inlet and outlet ends, the diameter of said outer casing being
greater than that of said inner casing to provide an annular
chamber therebetween; (c) an exhaust inlet fitting at the inlet end
of said inner casing; (d) an air inlet adjacent the inlet end of
said outer casing to allow air to flow into said annular chamber;
(e) vents in said inner casing adjacent said outlet end thereof to
permit air to flow from said annular chamber into the exhaust
flowing through said inner casing; and (f) baffle elements in said
inner casing, whereby exhaust flows through said inner casing about
said baffle elements and ambient air flows through said annular
chamber to provide a temperature at said outer casing which is
lower than that of said inner casing.
2. The muffler and exhaust extractor in accordance with claim 1
wherein the inlet end of said inlet fitting is of lesser diameter
than said inner casing and has an outwardly sloping wall extending
to said inner casing.
3. The muffler and exhaust extractor in accordance with claim 2
wherein said outer casing has an inner end portion extending over a
portion of said outwardly sloping wall of said inlet fitting and
said air inlet is provided in said inner end portion of said outer
casing.
4. The muffler and exhaust extractor in accordance with claim 3
wherein the end of said inner end portion of said outer casing is
secured to said sloping wall of said inlet fitting.
5. The muffler and exhaust extractor in accordance with claim 1
wherein there is included an end cap at the outlet-end of said
casings and wherein said casings are supported thereon.
6. The muffler and exhaust extractor in accordance with claim 1
wherein said baffle elements comprise: (a) a generally
frustoconical baffle in said inner casing adjacent said inlet end,
said frustoconical baffle being elongated with the smaller diameter
portion being spaced from said inlet end, the peripheral wall of
said baffle having perforations therein closely spaced about the
periphery and over the major portion of the axial length thereof,
said baffle being spaced from said inner casing over the major
portion of its axial length to provide an inlet end inner chamber
thereabout; and (b) a generally cylindrical baffle in said inner
casing having one end extending over the smaller diameter portion
of said frustoconical baffle, said cylindrical baffle having its
peripheral wall spaced from said inner casing over substantially
the entire length thereof to provide an elongated inner chamber
thereabout communicating with said inlet end inner chamber about
said frustoconical baffle, said peripheral wall having closely
spaced perforations extending circumferentially thereabout and over
the major portion of its length, whereby a substantial portion of
the volume of exhaust gases entering the inlet end of said
frustoconical baffle exits through said perforations in said
peripheral wall and thence moves generally axially in said chamber
thereabout and into said chamber about said cylindrical baffle, the
exhaust gases then passing into said cylindrical baffle through
said apertures therein and moving axially therethrough to said exit
end of said casing.
7. The muffler and exhaust extractor in accordance with claim 6
wherein the end of the smaller diameter portion of said
frustoconical baffle is open so that some of the exhaust gases pass
axially therethrough into the interior of said cylindrical
baffle.
8. The muffler and exhaust extractor in accordance with claim 6
wherein the apertures in the peripheral wall of said cylindrical
baffle are oriented in a spiral pattern.
9. The muffler and exhaust extractor in accordance with claim 6
wherein the inlet end of said frustoconical baffle is supported by
said inlet fitting which has an outwardly extending generally
cylindrical portion for connection to an element of the exhaust
system.
10. The muffler and exhaust extractor in accordance with claim 9
wherein the inlet end of said inner casing is secured to the outer
surface of said end cap.
11. The muffler and exhaust extractor in accordance with claim 6
wherein said outlet end of said cylindrical baffle is supported by
an end cap in said inner casing adjacent said outlet end
thereof.
12. The muffler and exhaust extractor in accordance with claim 6
wherein there is included heat-resistant fibrous material in said
elongated inner chamber to enhance sound reduction.
Description
BACKGROUND OF THE INVENTION
[0001] This invention is related to exhaust systems, and, more
particularly, to a muffler which will facilitate exhaust action and
noise abatement of high velocity exhaust gas flow and which has an
outer wall which has a reduced temperature.
[0002] Internal combustion engines and turbines produce exhaust
combustion gases and the discharged exhaust is frequently
accompanied by undesirable levels of noise. The problem of muffling
and evacuating such exhaust gases is well known.
[0003] Moreover, the hot exhaust gas quickly heats the outer wall
of the muffler to a temperature approaching that of the exhaust gas
and prolonged high temperature can produce discoloration of the
cosmetic finish on the outer wall.
[0004] In my U.S. Pat. No. 6,510,921 granted Jan. 8, 2003, I have
described an improved muffler which contains a pair of baffle
elements in a construction which reduces back pressure and
facilitates extraction of the exhaust from the engine. However, the
outer wall of the muffler reaches temperatures approaching that of
the exhaust gas passing therethrough and discoloration of the
cosmetic coating may occur.
[0005] It is an object of the present invention to provide a novel
muffler which provides cooling of the outer wall to minimize or
avoid discoloration of the cosmetic coating thereon.
[0006] It is also an object is to provide such a muffler with
components which can be readily fabricated and assembled to provide
a relatively long lived device.
[0007] Another object is to provide such a muffler which is
relatively low cost, is relatively lightweight and is resistant to
rust and corrosion.
SUMMARY OF THE INVENTION
[0008] It has now been found that the foregoing and related objects
may be readily attained in a muffler and exhaust extractor
comprising an inner elongated generally cylindrical casing having
inlet and outlet ends and an outer elongated generally cylindrical
casing having inlet and outlet ends. The diameter of the outer
casing is greater than that of the inner casing to provide an
annular chamber therebetween.
[0009] An exhaust inlet fitting is provided at the inlet end of the
inner casing, and an air inlet is provided adjacent the inlet end
of the outer casing to allow air to flow into the annular chamber.
Vents in the inner casing adjacent the outlet end thereof permit
air to flow from the annular chamber into the exhaust flowing
through the inner casing. The inner and outer casings are spaced
apart, and baffle elements are provided in the inner casing.
Exhaust flows through the inner casing about the baffle elements,
and ambient air flows through the annular chamber to provide a
temperature at the outer casing which is lower than that of the
inner casing.
[0010] The inlet end of the inlet fitting is of lesser diameter
than the inner casing, and it has an outwardly sloping wall
extending toward the inner casing. The outer casing has an inner
end portion extending over a portion of the outwardly sloping wall
of the inlet fitting, and the air inlet is provided in the inner
end portion of the outer casing. Desirably, the end of the inner
end portion of the outer casing is secured to the sloping wall of
the inlet fitting.
[0011] The preferred baffle elements comprise a generally
frustoconical baffle in the inner casing adjacent its inlet end,
and the frustoconical baffle is elongated with the smaller diameter
portion being spaced from the inlet end. The peripheral wall of the
baffle has perforations therein closely spaced about the periphery
and over the major portion of the axial length thereof. This baffle
is spaced from the inner casing over the major portion of its axial
length to provide an inlet end inner chamber thereabout.
[0012] The baffle elements also include a generally cylindrical
baffle in the inner casing having one end extending over the
smaller diameter portion of the frustoconical baffle. The
cylindrical baffle has its peripheral wall spaced from the inner
casing over substantially the entire length thereof to provide an
elongated inner chamber thereabout communicating with the inlet end
inner chamber about the frustoconical baffle. The peripheral wall
of the cylindrical baffle has closely spaced perforations extending
circumferentially thereabout and over the major portion of its
length. As a result, a substantial portion of the volume of exhaust
gases entering the inlet end of the frustoconical baffle exits
through the perforations in the peripheral wall and thence moves
generally axially in the chamber thereabout and into the chamber
about the cylindrical baffle. The exhaust gases then pass into the
cylindrical baffle through the apertures therein and move axially
therethrough to the exit end of the casing.
[0013] Desirably, the end of the smaller diameter portion of the
frustoconical baffle is open so that some of the exhaust gases pass
axially therethrough into the interior of the cylindrical baffle.
Preferably, the apertures in the peripheral wall of the cylindrical
baffle are oriented in a spiral pattern.
[0014] The inlet end of the frustoconical baffle is supported by
the inlet fitting which has an outwardly extending generally
cylindrical portion for connection to an element of the exhaust
system. The inlet end of the inner casing is secured to the outer
surface of the end cap. The outlet end of the cylindrical baffle is
supported by an end cap in the inner casing adjacent the outlet end
thereof.
[0015] Desirably, there is included heat-resistant fibrous material
in the elongated inner chamber to enhance sound reduction.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a semi-diagrammatic longitudinal sectional view of
an engine muffler/exhaust extractor embodying the present
invention; and
[0017] FIG. 2 is a sectional view along the line "AA" in FIG.
1.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT
[0018] FIG. 1 illustrates an engine muffler/exhaust extractor
embodying the present invention which is generally comprised of an
inner tubular or cylindrical casing generally designated by the
numeral 10 having an inlet end 12 and an outlet end 14, and an
outer tubular or cylindrical casing generally designated by the
numeral 16 having an inlet end 18 and an outlet end 20.
[0019] Seated within the inner casing 10 adjacent its inlet end 12
is a frustoconical baffle generally designated by the numeral 22.
Also seated within the casing 10 is a cylindrical baffle generally
designated by the numeral 24 which extends over the small diameter
end portion 26 of the frustoconical baffle 22 and is supported
adjacent the discharge end by the support cap generally designated
by the numeral 28. At the inlet end of the casing 10 is an inlet
fitting generally designated by the numeral 30. The baffles 22 and
24 are dimensioned so that there is an annular space between them
and the inner casing 10 providing a chamber 32 external to both
baffles 22, 24. The numerous arrows diagrammatically illustrate the
flow of the exhaust gases through the inlet fitting 30, baffles 22,
24 and chamber 32 to the outlet end 14.
[0020] Turning now in detail to the frustoconical baffle 22, the
central section thereof is provided with closely spaced apertures
34 extending about the periphery thereof providing communication
from its interior with the chamber 32. The apertures 34 extend over
the full length of the baffle 22. The small diameter end portion 26
and the large diameter end portion 36 are both imperforate although
the perforations 34 could be extended to both ends of the baffle 22
to facilitate use of fully perforated sheet material.
[0021] Turning next to the cylindrical baffle 24, the two end
portions are imperforate, but the entire center section is provided
with helically oriented closely spaced apertures 38 over its entire
length. The perforations 38 in the cylindrical baffle 24 are
preferably oriented in a helical pattern and the metal is deformed
thereabout to provide louver-like or scoop-shaped formations which
have an open end disposed towards the outlet end 14 of the casing
10 for a purpose to be described more fully hereinafter.
[0022] The inlet fitting 30 has a circular cross section throughout
its length. The larger diameter inner end portion 40 fits snugly
over the end of the casing 10, and the smaller diameter end portion
42 extends outwardly of the casing 10 for coupling to an adjacent
component of the exhaust system (not shown).
[0023] The inlet fitting 30 has an expanded inner end 44 providing
a frustoconical portion 46.
[0024] The outer casing 16 has a frustoconical inlet end portion 48
which is welded to the frustoconical portion 46 and is supported at
its outlet end 14 in the end cap 28. The conical portion 46 of the
outer casing 16 has an oval aperture 50 through which air flows
into the elongated annular chamber 8 until it exits through vent
apertures 52 in the inner casing 10.
[0025] Ambient air passes through the inlet aperture 50 into the
annular chamber 8 between the inner and outer casing 10, 16 and
flows therein to the vent apertures 52 where it exits into the
exhaust gases flowing out the cap 48.
[0026] Baffling material (not shown) when employed will normally
fill the entire chamber about the cylindrical baffle 24.
[0027] In a preferred structure, the casings 10, 16 increase in
diameter from the inlet ends to the outlet ends to facilitate flow
of exhaust gases therethrough. An increase of one inch over a
length of twenty-four inches has been found quite satisfactory.
[0028] As will be readily appreciated, the baffle components can be
readily fabricated by first pre-punching sheet metal such as
stainless steel and then forming the sheet material into the
frustoconical and cylindrical baffles. The abutted ends of the
sheet material can then be welded. The discharge end cap can be
stamped from sheet metal, and the casing and inlet end cap can both
be formed from tubing.
[0029] Although spacers may be provided between the inner and outer
casings, the welding of the casings to the inlet fitting at the
inlet end and the support provided by the cap at the outlet end is
sufficient to maintain the desired spacing.
[0030] Although various metals and ceramics may be employed for the
components, stainless steel is preferred for its resistance to
corrosion. For the fibrous sound absorbing materials, fiberglass is
preferred because of its low cost which allows the owner to replace
it from time to time to maintain high efficiency of flow through
the muffler.
[0031] As diagrammatically shown, the exhaust gases enter the
frustoconical baffle and are partially vented through the apertures
in its peripheral wall into the chamber thereabout. A substantial
portion of the exhaust gases continues on a direct path through the
reducing cross section of the baffle and is accelerated as it
passes from the nozzle-like end into the cylindrical baffle. As the
high velocity exhaust gas stream proceeds through the cylindrical
baffle, the exhaust gas which has entered the chamber passes
through the louvers and into the cylindrical baffle. The
combination of the forward orientation of the openings in the scoop
shaped louvers provides rapid flow of the exhaust gases
therethrough and they are swept along with the exhaust gas which
has passed directly into the cylindrical baffle.
[0032] With the current design of this muffler the air between the
inner and outer casings flows from front to back when the engine of
the vehicle is running because of the siphon effect of the exhaust
passing by the exit vents at the exit end of the inner casing. The
air is fed into the space between the inner and outer bodies by the
oval cut-out near the inlet end or front of the muffler. This
ambient (cool) air is at a lower temperature than that of the
exhaust gases. The outer casing is not in direct contact with the
exhaust gases or with the inner casing. This reduces heat transfer
to the outer casing thereby reducing the possible discoloration of
the chrome outer surface. This process is also enhanced when the
vehicle is in motion by air flowing into the chamber through the
slot at the inlet (front) of the muffler at a greater volume due to
the speed of the vehicle. The cooling effect of this air flow on
the outside of the casing will greatly reduce the temperature and
substantially reduce the potential for discoloration of the
cosmetic chrome finish on the outer casing.
[0033] Tests on mufflers embodying the present invention indicate
that the high speed flow of ambient air into the annular chamber
reduces the temperature of the outer casing and its cosmetic
coating so that there is no discoloration.
[0034] Thus, it can be seen from the foregoing detailed
specification and attached drawings that the novel muffler of the
present invention minimizes or eliminates the discoloration of the
cosmetic coating on the muffler. The components are readily
fabricated and relatively economical, and they can be readily
assembled to provide a muffler which will exhibit relatively long
life without discoloration.
* * * * *