US3317001A - Muffler - Google Patents

Description

May 2, w57 vv. H. POWERS ETAe.. 3,317,001

MUFFLER Original Filed Nov. 4 1963 May 2, 1967 vv. H. POWERS ETAL. 3,317,001

MUFFLEH 2 Sheets-Sheet 2 Original Filed Nov. 4, 1963 United States Patent O 3,317,001 M'UFFLER Walter H. Powers and Ervin C. Lentz, Racine, Wis., and Karl K. Kcrns, Jackson, Mich., assiguors to Walker Manufacturing Company, Racine, `Wis., a corporation of Delaware Continuation of application Ser. No. 321,007, Nov. 4, 1963. This application May 16, 1966, Ser. No. 550,574 Claims. (Cl. 181-36) 'I'his application is a continuation of our application Ser. Number 116,839, filed lune 13, 1961, and entitled, Muffler.

Our invention relates to the handling of exhaust gases and, in particular, concerns a combination exhaust gas conduit and silencer that is peculiarly well adapted for use on modern, low-slung automobiles.

It is an object of our invention to provide a combined conduit and silencing system that is very small in diameter and relatively long in length and adapted to readily t or be `tted in the small space allocated for the exhaust system in modern automobiles.

While other arrangements are possible, in a preferred form, our invention comprises a combined conduit and silencer unit that h'as a laminated pipe at its inlet end which receives exhaust gases from the exhaust manifold. A high pass silencing member is connected to the downstream end of the laminated pipe. The outlet of the high pass member is connected to a low pass member. There after the high pass and low pass members are alternated, the unit terminating in a low pass member.

The invention is illustrated in the accompanying drawings in which:

FIGURE 1 is a somewhat diagrammatic side elevation, partly broken away, of a combined exhaust conduit and silencing system embodying the principles of the invention;

FIGURE 2 is a cross-section broken away along a line 2 2 of FIG. l, showing a laminated pipe;

FIGURE 3 is a cross-section along a line 3--3 of FIG. 1 showing one form of high pass member that may be used;

V FIGURE 4 is a cross-section along the line 4-4 of FIG. 1 showing one form of low pass member that may be used;

FIGURE 5 is a section through another form of high pass silencing member; and

FIGURE 6 is a plan view, partly in section, of an exhaust system embodying the invention for use on a dual manifold engine, the low pass or spit chamber members being out of scale.

In FIG. 1 an internal combustion engine 1 has an exhaust manifold 3 which empties exhaust gases into an exhaust system 5. The system 5 is intended to replace the conventional exhaust system which comprises an exhaust pipe, a muler, and a tail pipe. The system 5 is in the form of a long conduit carrying the gases from the engine at the front end of the chassis of an automobile or truck to a discharge point at the rear of the vehicle. The system 5 is only slightly larger than the conventional exhaust or tail pipe (being preferably no larger than about 4 inches in maximum diameter and preferably about 3 inches) and can be bent in any direction at any point along its length, as well as flattened or shaped out of round, so that it can be fitted to the space available for it on the chassis of the vehicle with which it is to be used. The system 5 comprises, in downstream order, a pipe section 7, an expansion chamber 11, a pipe section 53, a set of spit chambers 15, a pipe section 55, an expansion chamber 13, a pipe section 57, and a set of spit chambers 17. The expansion chambers form high pass silencing elements and the sets of spit chambers form low pass silencing elements. The various parts of the system are suitably secured together, as by spotwelds x.

The first silencing component in system 5 is the pipe section 7 that conveys the gases away from the exhaust manifold 3. This should be formed of tubing having walls consisting of more than one layer of metal. We definitely prefer that the pipe 7 be laminated pipe comprising two or more imperforate, single wall, seam-welded pipes, one inside the other and in loose contact with each other. The pipe section 7 will act to contain side noise in this part of the system.

The second component of the system 5 is a high pass member in the form of an expansion chamber for attenuating notes in the exhaust gases. The system 5 utilizes two such members 11 and 13. It may be noted that by laminating the outer casing of the -rst expansion chamber 11, which is close to the exhaust manifold 3, member 11 can also act to contain or attenuate pipe noise. It is most desirable to have the laminated member as close as possible to the exhaust manifold 3 and if for some reason it is not possible or not desirable to use the laminated section 7, then the expansion chamber 11 should be laminated. Also, if it is found that lamination of the pipe section 7 is insufficient to contain side noise, the expansion chamber 11 may also be laminated as may pipe section 53.

The third component of the system 5 is a low pass member in the form of a set of spit chambers for removing roughness or sharpness and high frequencies not eliminated or contained by the expansion chambers or the laminated pipe. The system 5 utilizes two sets 15 and 17 of spit chambers, each of which includes several such chambers, preferably four or more. In a downstream direction it will be noted that the high pass member comes rst and the low pass member last and that the components are alternated. We prefer to have a set of spit chambers as close as possible to the end of system.

It is possible to incorporate within an expansion charnber other means for making the silencing more effective. For example, in the expansion chamber 11 we have a central transverse partition 19 and this supports a tube 21 as well as subdivides the casing 11 into two internal subchambers 23 and 25. The casing of the chamber 11 may be formed with integral reduced end sections 27 and 29 which contain and support an inlet tube 31 and an outlet tube 33. The confronting faces 35 and 37 of the tubes 31 and 21 may be cut off on sharp angles as shown and also may be provided with longitudinally extending slots 39. The same is true of confronting faces 41 and 43 of the tube 21 and the tube 33. The angled faces and the slots give a broad banding effect that increases the range of frequencies attenuated by the expansion chamber 11. In expansion chamber 13 a partition 45 subdivides the casing into two subchambers interconnected by a restrictive downstream extending neck 47 in partition 45, the neck 47 being preferably of substantially the same diameter as the inner diameter of pipe 7, 53, 55 and 57. The various expansion subchambers can be of the same or different volurnesv depending upon the acoustic results required by the particular application. We prefer to use a 3 -inch outer diameter and make the length of the expansion chamber 3 long enough to give sufficient volume, this length normally being many times the diameter of the pipe sections and in all cases preferably at least 12 inches.

The spit chamber sets 15 and 17 are in the form of chambered pipes and together contain a sufficient nurnber of chambers to eliminate roughness and high frequency sound. There are preferably at least four chambers in each set for optimum results. Each of the sets comprises an outer shell that is preferably about 21A inches in diameter which is reduced, as indicated at 47, to form a series of annular chambers 49. The chambers may be all of the same size and we have found that 3 inches is an optimum length. The ends of the shell are reduced in diameter to engage an internal straight-through pipe, such as the pipe 51, and to lit around the connecting pipe sections 53 and 57. The internal conduit 51 contains sets of louvers 59 opening into the chamber 49, such louvers preferably being of the type disclosed in U.S. Patent No. 1,949,074. It will be noted that in addition to being the optimum length acoustically, the 3 inch preferred length of the chambers 49 provides a structure that may be readily bent or flattened to suit the available space underneath an automobile or truck.

FIGURE 5 illustrates a high and medium pass silencing component in the form of a resonator chamber 61 which may be used to attenuate very low frequencies if they are found to be objectionable in the system 5 as previously described. The unit 61 would preferably be substituted for the chamber 11 through it may be placed at another point if that will be more effective. It comprises an inner tube 63 which is surrounded by an outer shell to form a chamber 65 around the tube. Large, non-restrictive openings 67 in the tube form the only inlet and outlet to the chamber 65 which therefore will act as a resonator or tuning chamber to eliminate low frequencies to which it is tuned. The size of the chamber 61 is preferably the same as that described in connection with the expansion chambers.

The various silencing components of system 5 may be more or less standardized for universal usage so that exhaust systems for various automobile models can be made up from them by interconnecting them in suicient number, and in optimum arrangement, by means of pipe sections.

The principles of system 5 may be embodied in a dual system as shown in FIG. 6 where there is an engine 101 having two exhaust manifolds 103 and an exhaust system 105 in the form of a long tail pipe or gas passage, the latter being shown in sections which would actually be connected together to form one continuous conduit. Each of the sections has an outer tube extending the full length of the section which is preferably three inches in maximum outer diameter. Two similar conduit sections 104 lead from each of the exhaust manifolds 103 and e'ach conducts the gases along a passage 107 into an eX- pansion chamber 109 and then into a set of four spit chambers 111. Gases leaving the two sets of spit chambers 111 enter conduit portions 113 which fit into a Y coupling 115 and thus merge the two gas paths to provide a high pass silencing effect.

It will be seen that the entire length of each of the sections 104 leading to the Y joint 115 is formed from tubing which is reduced in diameter at appropriate points to form the various chambers. An inner pipe 119 is inserted at the inlet or upstream end to form the laminated 1 portion 107. The outer pipe is reduced at opposite ends of the expansion chamber 109 as seen at 121 to provide a slight restriction and a larger variation in diameter as the gases enter and leave the expansion chamber. Inside of the spit chamber set 111 is a perforated tube 123 which is held in place by the reduced portion 121 and turned down portion 124 on the downstream side of the spit chamber portion.

A conduit portion 117 forms the outlet for the Y joint 115. This is the upstream end of a conduit section 125.

The conduit section 125 is connected to a conduit section 127 to complete the exhaust system. The sections 125 and 127 are formed in the same way as the sections 104, that is, each comprises a length of outer tubing which is reduced in diameter at appropriate spots to provide sets of spit chambers and expansion chambers similar to 111 and 109, respectively. Thus, the section 125 has a set of spit chambers 129, an expansion chamber 131, and another set of spit chambers 133. It terminates in a bushing section which will receive the upstream end `137 of the section 127. The section 137 may be bent in a kick-up 139 and it conducts gases to an expansion chamber 141. Gases flow downstream from chamber 141 to a set of spit chambers 143 located just ahead of end 145 of the system.

The sizes and functions of the various components of system 105 are preferably the same as described in connection with system 5.

The systems 5 and 105 may be ceramic coated. Also, some or all of the spit chambers may be filled with a sound absorptive type material (such as steel or copper wool) that will withstand acids and temperature of the type disclosed, for example in U.S. Patent 2,059,487. The conduits may be corrugated at points of severe bending.

Various modifications may be made in the structure shown without'departing from the broad spirit and scope of the invention. The system may be used with inboard boats as well as automobiles.

We claim:

1. A silencing system for an internal combustion engine having an exhaust manifold comprising a section of laminated pipe for connection at one end directly to the exhaust manifold and forming means for silencing side noises, an expansion chamber directly connected to the other end of the laminated pipe and forming means for silencing notes, a series of spit chambers at the outlet end of the system and forming means for silencing roughness, and conduit means connecting said spit chambers to said expansion chamber.

2. A small diameter, long length silencing system and tailpipe for an internal combustion engine having an eX- haust manifold comprising a laminated pipe for connection to the manifold, a series of high pass silencing members and low pass silencing member connected to and alternating with each other, the'first of said high pass silencing members being connected to the end of said laminated pipe, said system terminating in a low pass silencing member.

3. A silencing system for motor vehicles such as a passenger automobile having a chassis and an internal combustion engine mounted at the front end of the chassis comprising a series of tube sections and chambers connected together to form a gas passage extending from said engine to the rear end of said chassis, said chambers and tube sections containing sound silencing means for attenuating the noise in exhaust gas passing therethrough, said sound silencing means including high pass chambers of more than about 12 inches in length and low pass chambers of about 3 inches in length, said chambers being no larger than about 4 inches in diameter and said tube sections being considerably smaller than 4 inches in diameter, the downstream order of said sound silencing means comprising a laminated pipe, a high pass chamber means, and a low pass chamber means.

V4. A combination straight through flow exhaust gas conduit and silencer device to conduct gases from the exhaust manifold of an internal combustion engine on a vehicle through a continuous straight through 110W passage to a discharge point located at a remote point on the vehicle and to simultaneouly silence the exhaust gases while conducting them to said discharge point, said device having an inlet end and an outlet end, a series of expansion chamber members and spit chamber members between said inlet end and said outlet end to silence the gas, said expansion chamber members and said spit chamber members being alternated along the length of the device, gas passage sections in said device interconnecting said chamber members, said lgas passage sections being smaller in diameter than said chamber members to provide a series of changes in diameter of the flow passage, and a laminated conduit forming element at the inlet end of the device.

5. A combination straight through flow exhaust gas conduit and silencer device to conduct gases from the exhaust manifold of an internal combustion engine on a vehicle through a continuous straight through flow passage to a discharge point located at a remote point on the vehicle and to simultaneously silence the exhaust gases while conducting them to said discharge point, said device having an inlet end and an outlet end, a series of expansion chamber members and spit chamber members to silence the gas, said expansion chamber members and said spit chamber members being alternated along the length of the device, gas passage sections in said device interconnecting said chamber members and a laminated conduit forming element at the inlet end of the device.

6. A combination straight through flow exhaust gas conduit and silencer device to conduct gases from the exhaust manifold of an internal combustion engine on a vehicle through a continuous straight through flow passage to a discharge point located at a remote point on the vehicle and to simultaneously silence the exhaust gases while conducting them to said discharge point, said device having an inlet end and outlet end, a series of expansion chamber members and spit chamber members to silence the gas, and gas passage sections in said device interconnecting said chamber members, and a laminated conduit forming element at the inlet end of the device.

7. A combination straight through ow exhaust gas conduit and silencer device to conduct gases from the exhaust manifold of an internal combustion engine on a vehicle through a continuous straight through ow passage to a discharge point located at a remote point on the vehicle and to simultaneously silence the exhaust gases while conducting them to said discharge point, said device having an inlet end and an outlet end and a series of chamber members therebetween to silence the gas, a length of integral continuous solid wall outer pipe forming the outer wall of said device, said outer pipe having varying diameters and providing large diameter portions and small diameter portions, integral continuous internal pipe mounted within at least some portions of said outer pipe and providing a straight through gas flow passage therein and extending through at least one of said large diameter portions between spaced small diameter portions iat each end of said one large diameter portion to provide at least one silencing chamber member defined by the inner surface of said outer pipe and the outer surface of said inner pipe, passage means extending through the wall of said inner pipe and connecting said one silencing chamber member to said straight through gas ow passage, and at least the inlet end of said device being formed by a section of laminated pipe.

8. An exhaust gas system comprising only long small diameter exhaust gas pipe providing a straight through gas ilow passage extending continuously between a gas inlet and a gas outlet, sound attenuating chamber means formed in said gas tlow passage by only two coaxial telescopically mounted pipe members, said chamber sound attenuating means being formed by a iirst length of integral continuous wall outer pipe forming the outer wall of said exhaust pipe, the end portions of said length of outer pipe being of reduced diameter, intermediate portions of said outer pipe being of reduced diameter, the end portions and said intermediate portions of reduced diameter having a common inside diameter and being circumferentially continuous at the inner surface, a length of inner pipe forming a part of the gas ow passage extending the length of the pipe and having an outside diameter approximately equal to the inside-'diameter of the end portions and said intermediate portions of reduced diameter, the end portions and said intermediate portions frictionally engaging the outer surface of said inner pipe and dividing said sound attenuating chamber means into a plurality of chamber portions along the length of pipe, gas passage means extending through the wall of the inner pipe and connecting said gas lloW passage to said sound attenuating chamber means, and a laminated conduit forming element at the inlet end of said exhaust system.

9. In a motor vehicle having an internal combustion engine emitting exhaust gases, an exhaust gas silencing system for conveying gases from the engine beneath the vehicle for discharge at a remote point and to silence sound associated therewith en route to the discharge point, said system being of irregular contour for positioning within the space beneath the vehicle it is to occupy, said system comprising at least two different exhaust gas silencing units separated each from the other along the path of exhaust gas in the system and exhaust gas conduits interconnecting said units in series in said system and connecting them to the engine to receive exhaust gas, one of said silencing units having a housing and means for silencing exhaust gases within said housing, the last named means of said one unit comprising structure tuned to primarily attenuate low and medium frequency sounds in the exhaust gases, the other of said units being adapted to attenuate the high frequency sounds and roughness in the exhaust gas and consisting solely of an outer housing, an exhaust gas inlet, an exhaust gas outlet, an inner exhaust gas flow tube for conveying gas through the housing from said exhaust gas inlet to said exhaust gas outlet, said inner tube having a relatively large number of perforations formed therein between its respective ends, and wall means for dividing the volume between said tube and said housing into a plurality of chambers, said housing being only slightly larger in cross-section than said tube and said chambers being a small volume and in acoustic communication with the gas flowing through said tube via the perforations in said tube for attenuating high frequency sounds and roughness.

10. In a motor vehicle having an internal combustion engine emitting exhaust gases, an exhaust gas silencing sys-tem for conveying gases from the engine beneath the vehicle for discharge at a remote point and to silence sound associated therewith en route to the discharge point, said system being of irregular contour for positioning within the space beneath the vehicle it is to occupy, said system comprising three different exhaust gas silencing units separated each from the others along the path of exhaust gas in the system and exhaust gas conduits interconnecting said units in series in said system and connecting them to the engine to receive exhaust gas, two of said silencing units having housings and means for silencing exhaust gases within said housings, the last named means of said two units comprising structure tuned to primarily attenuate low and medium frequency sounds in the exhaust gases, the third of said units being adapted to attenuate the high frequency sounds and roughness in the exhaust gas and consisting solely of an outer housing, an exhaust gas inlet, an exhaust gas outlet, an inner exhaust gas flow tube for conveying gas through the housing from said exhaust gas inlet to said exhaust gas outlet, said inner tube having a relatively large number of perforations formed therein between its respective ends, and wall means for dividing the volume between said tube and said housing into at least three chambers, said housing being only slightly larger in cross-section than said tube and said chambers being of small volume and in acoustic communication with the gas flowing through said tube via the perforations in said tube for attenuating high frequency sounds and roughness.

(References on following page) 7 S References Cited by the Examiner FOREIGN PATENTS UNITED STATES PATENTS 2,059,487 11/1936 Peik 181-41 1639940 951952 Grrggtain,

Mackenzie et al Italy. 2,770,313 11/1956 Johnson 181-36 5 2,8088 6 10/1 '1 181-36 2,855,028 :l0/132g 18]. 42 STEPHEN I. TOMSKY, Plmy Exml1e- 3,009,484 11/1961 Douons 181-61 X 3,104,735 9/1963 Ludlow er a1. 181-36 LEO SMILOW Exammer'

Claims (1)

1. A SILENCING SYSTEM FOR AN INTERNAL COMBUSTION ENGINE HAVING AN EXHAUST MANIFOLD COMPRISING A SECTION OF LAMINATED PIPE FOR CONNECTION AT ONE END DIRECTLY TO THE EXHAUST MANIFOLD AND FORMING MEANS FOR SILENCING SIDE NOISES, AN EXPANSION CHAMBER DIRECTLY CONNECTED TO THE OTHER END OF THE LAMINATED PIPE AND FORMING MEANS FOR SILENCING NOTES, A SERIES OF SPIT CHAMBERS AT THE OUTLET END OF THE SYSTEM AND FORMING MEANS FOR SILENCING ROUGHNESS, AND CONDUIT MEANS CONNECTING SAID SPIT CHAMBERS TO SAID EXPANSION CHAMBER.

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