US3129078A - Exhaust muffler filter - Google Patents

Description

April 14, 1964 M. L. HOBBS 3,129,078

' EXHAUST MUFFLER FILTER Filed June 16. 1961 INVENTOR. HOB 5 ATTORNEYJ United States Patent 3,129,078 EXHAUST MUFFLER FILTER Marian L. Hobbs, 916 Orville, Kansas City, Kans- Filed June 16, 1961, Ser. No. 117,548 3 Claims. (Cl. 55-313) This invention relates to improvements in muiflers or silencers of the type employed with internal combustion engines, and more particularly to a muffler or silencer for use on exhaust pipes of motor vehicles for both silencing the explosive noises and removing smog-forming elements from exhaust gases.

Due to the noise produced by exhaust gases from internal combustion engines being exhausted directly into the air, it is usually necessary to provide them with devices to mufile or silence such noises. The exhaust gases also carry impurities such as carbon particles and gases which are offensive in smell and often dangerous. Under certain conditions, the exhaust gases of motor vehicles when discharged into the air introduce smog-forming elements in the air which cause an accumulation of what is commonly called smog, particularly in large cities and substantial accumulations in the air are offensive and, in many instances, harmful to life and property. Filters for exhaust gas will tend to remove some smogforming elements, but obstructions in the exhaust pipes which cause back pressure on the exhaust ports of an engine will substantially reduce the power and efliciency of the engine, and it has been found that where attempts have been made to pass all of the exhaust gas of a motor vehicle through a filter, the carbon particles and the like fill the voids in the filter to the point that it becomes an obstruction with a rapid drop of efficiency in performance of the engine.

The principal objects of the present invention are to provide a mulfler for connection in an exhaust pipe of an internal combustion engine which, in addition to silencing the exhaust noises, will remove smog-forming elements from the exhaust gases; to provide such a muffler structure with gas filtering elements therein and bypass passages around the filtering elements whereby the engine can perform if gas flow through the filtering elements is obstructed; to provide such a structure wherein the bypass passages are arranged to provide slight restriction to flow of exhaust gases therethrough to cause the principal portion of the gases to pass through the filtering element; to provide such a mufller structure that is adapted to be installed in an exhaust pipe of a motor vehicle in place of the regular mufller without altering the parts of the vehicle or as a smaller size in addition to the regular muffier; and to provide an internal combustion engine muffler that is economical to manufacture, that is efficient in reducing exhaust noise and in removing smog-forming elements from the exhaust gases with a minimum of resistance or retardation of flow of exhaust gas therethrough.

Other objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings wherein are set forth by way of illustration and example certain embodiments of this invention.

FIG. 1 is a perspective view of a muffler embodying the features of the present invention.

FIG. 2 is a longitudinal sectional view through a modified form of mufiler.

FIG. 3 is a transverse sectional view through the mufiler illustrated in FIG. 2 taken on the line 33, FIG. 2.

FIG. 4 is a longitudinal sectional View through a further modified form of muffier.

FIG. 5 is a transverse sectional view through the muffler shown in FIG. 4 taken on the line 5-5, FIG. 4.

FIG. 6 is an enlarged transverse sectional view through the bypass valve in open position.

Referring more in detail to the drawings:

1 generally designates a mufiler filter structure having a tubular imperforate shell or casing 2 having end walls 3 and 4 suitably attached thereto. In the illustrated structure, the end walls have outwardly directed peripheral flanges 5 and the ends of the casing overlie said flanges and are turned inwardly to underlie the flanges as at 5 and are suitably secured thereto in a substantially gastight seal. The end walls 3 and 4- each have outwardly turned flanges 7 defining a bore 8 in which is mounted a short tubular extension with the inlet extension in the end wall 3 arranged for reception of an exhaust pipe 10, the tubular outlet extension 9 in the end wall 4 being received in a tailpipe 11 The extensions 9 and 9 are suitably secured as by welding to the flanges 7 of the end walls 3 and 4 to form a gas-tight connection, and the extensions 9 and 9 are secured to the exhaust pipe 10 and tailpipe 11 respectively in any suitable conven tional manner. The inner ends of the extensions 9 and 9 have annular flanges 12 and 12' respectively extending substantially radially therefrom and terminating in spaced relation to the wall of the casing 2 to provide a passage therebetween. A perforate shell 13 has ends suitably secured as at 14 to the peripheral edges of the flanges 12 and 12 to define a space extending between the inner ends of the extensions 9 and 9, and said space is filled with a fibrous filtering material 15 such as a mass of glass fibers. formed of a wire mesh but may be of other perforate material that will retain its shape and confine the fibrous filter material.

A bypass around the filtering material 15 is provided by a plurality of apertures 16 on the extension 9 of the end wall 3 and a plurality of apertures 17 in the extension 9' on the end wall 4, said apertures being between the annular flanges 12 and 12' and the respective end walls 3 and 4, and, also, of suitable size and quantity wherein the combined area of the apertures 16 or the combined area of the apertures 17 equals or is greater than the area in the exhaust pipe 10. Flow of exhaust gas through the apertures 16 is retarded by suitable valve members 18 which will open under very small pressure, the valve members being biased toward closing position. In the illustrated structure, the valve members 18 consist of flat, leaf-like spring members curved to fit the outside contour of the extension 9 with one end of each of the valve members secured by suitable fastening device such as a rivet 19 to the extension 9 and spaced circumferentially of the apertures 16. The valve members 18 are biased to closing position whereby under normal operating conditions the valves remain closed and the exhaust gas passes into the filtering material in the shell 13, but if resistance to flow of the exhaust gases through the filtering material is increased, the resulting increased pressure in the extension 9 will cause the valve members to open whereby the exhaust gases will escape through the apertures 16 and pass through the space 211 between the shell 13 and the casing 2 and enter the apertures 17 for discharge through the tailpipe 11.

In using a muffler constructed and assembled as described, and with the mufiler connected to an exhaust pipe 10 and tailpipe 11 as illustrated, operation of the internal combustion engine connected to the exhaust pipe 10 will direct the gases into the filter media 15 in the shell 13. Some of said exhaust gases will pass through the length of the shell into the extension 9' on the end 'wall 4 and be discharged through the tailpipe 11. A

portion of the gas will escape radially through the filter media and through openings 21 in the shell whereby said In the illustrated structure, the shell 13 is escaping gases will pass through the space 20 to the apertures 17 and through the extension 9' to the tailpipe 11. The filter media will remove carbon particles and smogforming elements and thereby reduce the possibility of smog being formed in the area in which the vehicle is operated. As carbon and other elements are accumulated in the filter media 15 sufficiently to close the spaces between the fibers and retard flow of exhaust gas therethrough, the pressure within the extension 9 on the end wall 3 will increase slightly and cause the valves 18 to open for flow of some of the exhaust gas through the apertures 16, space 2%) and into the apertures 17, bypassing the filter element. During this bypass of a portion of the exhaust gas, there will be some gas passing through the filter whereby it will still be operative to reduce the quantity of smog-forming elements therein. However, even after the filter element is completely filled to stop flow of exhaust gases therethrough, the engine will continue to operate as the exhaust gases then will cause the valves 18 to open and bypass the filter element, whereby the vehicle can be operated until an opportunity is obtained for replacing the muffler and filter unit.

In the form of the invention illustrated in FIG. 2, the muffier unit 22 has a shell 2, end walls 3 and 4, and extensions 9, annular flanges 12 on the inner ends of the extensions, and a perforate shell 13 containing filter media 15 such as fiberglass that are substantially the same structure and assembled in substantially the same manner as in the muffler 1 illustrated in FIG. 1. In the mufier 22,

a filter medium such as fiberglass or the like is arranged in a layer 23 around the inside of the casing 2 with said filter media retained in place by a perforate tubular member 24 which, in the illustrated structure, is in the form of a wire mesh cylinder spaced outwardly from the shell 13 to provide a through space or passage 25 therebetween. In place of the apertures 16 in the inlet extension 9, there are ducts 26 having inlets 27 communicating with the bore 28 in the inlet extension 9 between the flange 12 and the wall 3. Said ducts are spiraled around the shell 13 toward the end Wall 4 and terminate in open ends 29. The ducts 26 are preferably perforated whereby gases passing therethrough may escape toward the shell 13.

In using a muffier and filter structure as illustrated in FIGS. 2 and 3, with the mufiier inlet connected to an exhaust pipe 10 and the outlet received in a tailpipe 11 and, with the internal combustion engine operating, the exhaust gases will be directed through the inlet extension 9 into the filter media 15 in the shell 13. A portion of the exhaust gases will bypass said filter, passing into the ducts 26 and escape through the apertures 30 thereof for flow through the space 25 into the inlet apertures 17 of the outletextension 9 for discharge through the tailpipe 11. The flow of exhaust through the ducts 26 is retarded by the size and length thereof so as to cause the exhaust gas to tend to pass through the filter media 15 to the outlet extension 9'. However, some of the gas will pass through the ducts 26 and be directed through small apertures 30 in said ducts which will tend to direct particles into the filter media 15 and the filter media 23, whereby some of the exhaust gas is filtered at all times and the smog-forming elements are reduced.

In the form of the invention illustrated in FIG. 4, the muffler and filter 31 is substantially the same structure as the mufiier and filter illustrated in FIG. 1 except filter media 23 is arranged around the interior of the casing 2 and held in place with a perforate cylindrical member 24 which is illustrated as being a wire mesh. A spiral bafile 32 has one end secured to the annular flange 12 at the inlet extension and extends in a spiral in the space between the shell 13 and the perforate member 24 and terminates as at 34 adjacent the annular flange 12' on the outlet extension 9 whereby exhaust gases escaping through the valve bypass apertures 16 and are directed in a tortuous passage in the space 33 before they reach the apertures 17 to reenter and be discharged through the tailpipe 11. With this arrangement, the bypassed exhaust gases must travel a longer route and in contact with filter elements both inwardly and outwardly of the passage to tend to remove additional carbon and smog-forming elements. With this addition, the muffler and filter 31 operate substantially as the structure illustrated in FIG. 1.

It is to be understood that while I have illustrated and described certain forms of my invention, it is not to be limited to the specific forms or arrangements of parts herein described and shown except insofar as such limitations are included in the claims.

What I claim and desire to secure by Letters Patent is:

1. An exhaust mufiler filter for internal combustion engines comprising, open-ended inner and outer metal shells in substantially concentric relation, said shells being radially spaced with a longitudinal passage therebetween, the outer shell being substantially imperforate and the inner shell being perforate, end walls in said outer shell to close the ends thereof, the inner shell being shorter in length than the outer shell with the ends of the inner shell adjacent to and spaced from the end walls, an inlet duct extending through one end wall and an outlet duct extending through the other end wall, means on inner ends of the inlet and outlet ducts supporting the inner shell, a fibrous filter media filling said inner shell between said inlet and outlet ducts whereby exhaust gases moving from the inlet duct to the outlet duct normally pass through said filter media, said inlet and outlet ducts having apertures therein between the ends of the inner shell and the end walls of the outer shell, and valve members on the inlet duct for said apertures therein and biased into aperture closing position for normally closing said apertures against normal operating pressures in the inlet duct, said valve members being opened in response to increase of pressure in the inlet ducts resulting from increase of resistance to fiow through the filter media and thereby permitting flow of exhaust from the inlet duct through the passage between the inner and outer shells to the outlet duct bypassing the filter media in the inner shell.

2. An exhaust mufiier filter for internal combustion engines comprising, an elongate imperforate casing, end walls closing end portions of said casing, atubular duct in one end wall and forming an inlet for exhaust into said casing, a tubular duct in the other end wall and forming an exhaust outlet from said casing, said inlet and outlet ducts having open ends in the casing adjacent said end walls and spaced therefrom, a foraminous. shell extending between said open ends of the ducts and defining a cross sectional area substantially greater than that of the ducts, shell end members mounted on the ducts and extending radially outwardly therefrom and secured to the ends of the shell to support said shell and form closures for the ends in spaced relation to the end walls of the casing, said foraminous shell being spaced from the casing to define a longitudinal passage therebetween in surrounding rela tion to said shell, a fibrous filter media filling said foraminous shell for the length thereof for receiving exhaust gases from the inlet duct which said gases are discharged longitudinally into said filter media, said outlet duct having an aperture therein between the adjacent end member of the foraminous shell and the end wall of the casing for escape of exhaust gases flowing from the filter media through the foraminous shell into the longitudinal passage between the shell and casing, and means operable in response to increase of pressure in the inlet duct for bypassing a portion of the exahust through the longitudinal passage between the casing and shell to the aperture in the outlet duct.

3. An exhaust muifier filter for internal combustion engines comprising, an elongate imperforate casing, end walls closing end portions of said casing, a glass fiber mass supported in lining relation to said imperforate casing, a tubular duct in one end wall and forming an inlet for exhaust into said casing, a tubular duct in the other end wall and forming an exhaust outlet from said casing, said inlet and outlet ducts having open ends in the casing adjacent said end walls and spaced therefrom, a foraminous shell extending between said open ends of the ducts and defining a cross-sectional area substantially greater than that of the ducts, said shell being spaced from the glass fiber mass lining said casing to define a passage therebetween, means on said ducts in spaced relation to the end walls and supporting the ends of the foraminous shell and closing said ends between the shell and the ducts, a glass fiber mass filling said foraminous shell for the length thereof whereby exhaust gases from the inlet duct are discharged longitudinally into said glass fiber mass filling said inner shell, means operable in response to increase of pressure in the inlet duct for bypassing a portion of the exhaust through the casing between the casing and shell to the outlet duct, and a wall extending from the forarninous shell to the casing lining and spiraled longitudinally around said forarninous shell to define a spiral passage between said foraminous shell and the casing lining for the bypassed exhaust gas.

References Cited in the-file of this patent UNITED STATES PATENTS

Claims (1)

1. AN EXHAUST MUFFLER FILTER FOR INTERNAL COMBUSTION ENGINES COMPRISING, OPEN-ENDED INNER AND OUTER METAL SHELLS IN SUBSTANTIALLY CONCENTRIC RELATION, SAID SHELL BEING RADIALLY SPACED WITH A LONGITUDINAL PASSAGE THEREBYTWEEN, THE OUTER SHELL BEIN SUBSTANTIALLY IMPERFORATE AND THE INNER SHELL EING PERFORATE, END WALLS IN SAID OUTER SHELL TO CLOSE THE ENDS THEREOF, THE INNER SHELL BEING SHORTER IN LENGTH THAN THE OUTER SHELL WITH THE ENDS OF THE INNER SHELL ADJACENT TO AND SPACED FROM THE END WALLS, AN INLET DUCT EXTENDING THROUGH ONE END WALL AND AN OUTLET DUCT EXTENDING THROUGH THE OTHER END WALL, MEANS ON INNER ENDS OF THE INLET AND OUTLET DUCTS SUPPORTING THE INNER SHELL, A FIBROUS FILTER MEDIA FILLING SAID INNER SHELL BETWEEN SAID INLET AND OUTLET DUCTS WHEREBY EXHAUST GASES MOVING FROM THE INLET DUCT TO THE OUTLET DUCT NORMALLY PASS THROUGH SAID FILTER MEDIA, SAID INLET AND OUTLET DUCTS HAVING APERTURES THEREIN BETWEEN THE ENDS OF THE INNER SHELL AND THE END WALLS OF THE OUTER SHELL, AND VALVE MEMBERS ON THE INLET DUCT FOR SAID APERTURES THEREIN AND BIASED INTO APERTURE CLOSING POSITION FOR NORMALLY CLOSING SAID APERTURES AGAINST NORMAL OPERATING PRESSURES IN THE INLET DUCT, SAID VALVE MEMBERS BEING OPENED IN RESPONSE TO INCREASE OF PRESSURE IN THE INLET DUCTS RESULTING FROM INCREASE OF RESISTANCE TO FLOW THROUGH THE FILTER MEDIA AND THEREBY PERMITTING FLOW OF EXHAUST FROM THE INLET DUCT THROUGH THE PASSAGE BETWEEN THE INNER AND OUTER SHELLS TO THE OUTLET DUCT BYPASSING THE FILTER MEDIA IN THE INNER SHELL.

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