JPH0337320A - Exhaust gas muffler - Google Patents

Abstract

PURPOSE: To facilitate manufacturing of a muffler by inserting a pair of tubular pipes having a porous part between a pair of external shells, and forming the external shells including a plurality of chambers which the porous portions of respective pipes face and is separated by baffle creases. CONSTITUTION: This exhaust muffler 10 consists of external shells 12, 14 constituted of metallic plate or the like and tubes 16, 18 at least partially-disposed inside the external shells. The outer shells 12, 14 are formed so as to be roughly symmetric to each other and involve baffle creases 30, 60 connecting the separated parts of a peripheral flanges 24, 25. The baffle creases 30, 60 involve flat base parts 32, 34, 36, 62, 64, 66 and arch-shaped parts 38, 40, 68, 70, and respective arch-shaped parts are formed so as to have dimensions capable of engaging with tubes 16, 18. The external shells 12, 14 involve respectively chambers 42, 44 and 72, 74 which are reinforced respectively by recessed parts 46, 48 and 76, 78, and the porous parts of respective tubes 16, 18 are disposed between respective chambers 42, 72 and 44, 72.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an exhaust muffler.

BACKGROUND OF THE INVENTION A vehicle exhaust system includes one or more pipes for conveying exhaust gases from the engine. Each pipe leading from the engine leads to a catalytic converter that works to convert certain unpleasant gases in the exhaust stream into less unpleasant forms.The exhaust pipes lead from the catalytic converter to a muffler that reduces the noise associated with the exhaust gas stream. The tailpipe therefore extends from the muffler to a point on the vehicle where the exhaust gases can be safely and conveniently released.

A typical prior art muffler has a plurality of separate tubes supported in parallel rows by a plurality of laterally extending baffles. Selected portions of each tube have holes, shutters, or openings through which exhaust gases moving can be vented in a controlled manner.

Each tube is typically rigidly coupled to at least one baffle, and the assembled rows of parallel tubes and transverse baffles form a generally tubular shell with a circular or oval cross-sectional shape corresponding to the shape of the baffle. You can slip inside. A separate outer wrapper is typically wrapped around the outer shell to dampen noise associated with shell vibrations. a pair of opposing end caps, a header in turn being securely coupled to the longitudinal ends of the opposing tubular shell and outer envelope substantially enclosing the muffler, each end cap typically having at least one opening; and can communicate with the inside of the muffler. The opening in the end cap typically aligns with one of the tubes inside the muffler. The assembly of elements within this representative prior art muffler forms a plurality of chambers.

In particular, the chamber is formed between the tubular shell and either of a pair of spaced apart baffles, or between one baffle and one end cap of a prior art muffler.

The relative distances of the baffles within the muffler, the dimensions of the tubes therein, the shutters, the openings, etc., are all selected to provide specific attenuation of exhaust gas noise. In particular, the exhaust gases flowing through the device pass through various holes, shutters, openings, etc. and are engraved into corresponding chambers to achieve a specific noise attenuation.

When considering the above exhaust muffler in relation to the original equipment,
Mufflers are typically welded to an elongated, winding exhaust pipe and tailpipe. The muffler, exhaust pipe, and tailpipe assembly is then shipped to the original vehicle manufacturer so that the completed exhaust system assembly can be installed on the vehicle.

The prior art muffler and exhaust system elements described above adequately attenuate noise associated with exhaust gas flow. However, prior art exhaust mufflers require a large number of separate elements that must be assembled in a labor-intensive manufacturing process. The resulting muffler is likely to be unnecessarily heavy, and there are few design choices regarding the shape of the muffler or the alignment of pipes leading to or from the muffler.

These inherent limitations with the prior art mufflers described above make it extremely difficult to fit an exhaust system into the limited available space on the underside of a vehicle.

The prior art further discloses a muffler that is free from stamped forming elements. For example, U.S. Pat. There is. The inner plates are assembled so that the edges meet each other to form a tube therebetween. The inner plate is then placed within the conventional wrap-type outer shell described above to form a muffler. A separate inner baffle extends between the stamped plate and the wrapped outer shell, as described in U.S. Pat. No. 439
A chamber is formed in the muffler of No. 6090.

The prior art further includes mufflers consisting of only two opposing shells, the shells being stamped to form a thinly wound row of stamp-forming tubes and a stamp-forming chamber. Mufflers of this type are shown in U.S. Pat. No. 2,484,827, U.S. Pat. No. 3,176,791, and U.S. Pat. No. 3,638,756.

The prior art further includes a muffler formed from four stamped elements. This type of muffler has a pair of inner plates stamped to form opposing sides. The plates are mounted in facing relation to each other and the opposing plates form a tube. The inner plate also has stamped holes, shutters, etc. to allow engraving of the exhaust gases from the forming tube. The mufflers further include a pair of stamped outer shells that surround the inner plate to define an enclosing chamber.

The chamber forms an enclosed volume within which the exhaust gas engraves. This - forged prior art muffler is described in British Patent No. 63
2013, UK Patent No. 1012463.

As shown in US Pat. No. 4,132,286.

Some prior art mufflers are formed from three or more stamped elements and also a plurality of tubular elements. For example, U.S. Pat. and the inner plate is stamped to form at least one plate. A conventional tube member that fits the mold of the mold in the perforated plate is supported and retained by the mold. The muffler of U.S. Pat. No. 4,132,286 further includes a pair of opposed stamped outer shells that effectively form a bivalve around a perforated inner plate and a tube supported therein. US Patent No. 41
The muffler shown in No. 32286 effectively forms only one inner chamber in which the exhaust gases engrave. The acoustic articulation ability of this forged muffler is extremely limited, and U.S. Pat.
It is extremely difficult to achieve muffler noise attenuation requirements for many vehicles made and sold in the United States with mufflers such as those shown in No. 32286.

A muffler similar to that shown in US Pat. No. 4,132,286 is shown in British Patent No. 2,120,318.

In particular, GB 2,120,318 shows a muffler having a plurality of tubes supported in parallel rows by a plurality of laterally extending baffles. The rows of tubes and baffles are placed within a generally clam-shaped opposed stamped outer shell. However, British Patent No. 21203
The outer shell shown in No. 18 is a highly complex stamped part which also forms both a stamped exhaust pipe and a stamped tailpipe. The stamped outer bivalve shell and integrally stamped exhaust pipe and tail pipe require extremely expensive dies. On top of that,
The internal elements required in GB 2,120,318 inherently require a combination of tubes and separate baffles that must be assembled within the labor-intensive manufacturing process described above with respect to prior art mufflers.

Yet another prior art muffler incorporating both tubular and stamped elements is shown in JP-A-59-43456. Unlike the above two, JP-A-59-4
The muffler shown in the '3456 publication has at least four stamped elements combined with a tubular element. In particular, the muffler shown in JP-A-59-43456 has a pair of stamped inner plates with grooves formed therein which form a tube when the inner plates are placed in facing relationship. Additionally, each inner plate portion is folded approximately at right angles to the remaining portions of the plate to form a laterally extending wall of the stamped forming tube. A separate stamped and formed baffle is also provided. Unexamined Japanese Patent Publication 1987-
The muffler shown in the '43456 publication further includes a pair of stamped outer bivalve shells surrounding the inner plate. The outer bivalve shell and the folded portion of the inner plate form a complementary shape, and the folded portion of the inner plate forms a baffle within the muffler. The muffler further includes a tubular member extending between the outer shell and a baffle formed by the folded portion of the inner plate.

The muffler disclosed in Japanese Patent Application Laid-Open No. 59-43456 is extremely complicated, expensive, and difficult to assemble. In particular, this muffler has at least four stamped forming elements and correspondingly requires specialized gougs and a pair of separate tubular members. The inner stamped plates must be assembled and welded together, the separate tubular members must be securely connected to the stamped inner plate by welding or the like, and the separate baffles must be securely connected to the stamped inner plate. The opposing bivalve shells must be securely assembled around a subassembly consisting of opposing stamped inner plates, separate baffles, and separate tubes.

[Problems that Qming seeks to solve] The above-described prior art die-formed mufflers offer certain advantages over conventional mufflers with wrapped outer shells. In particular, many of the stamped mufflers mentioned above are lighter than ordinary mufflers and can be made by processes well suited for automation. However, many of the prior art stamped mufflers described above have not achieved a degree of acoustic articulation that is acceptable in vehicles built or sold in the United States as a whole; as a result, until recently, stamped and formed mufflers have not been sufficiently manufactured in the United States. has not achieved significant commercial success.

Recently, there have been some significant advances in stamped and formed mufflers. In particular, US Pat. No. 4,700,806 shows a muffler formed from stamped elements and combining at least one tuning tube and at least one low frequency resonant chamber. One example of a muffler shown in U.S. Pat. No. 4,700,806 shows a pair of inner plates formed to form grooves therein. The plates are attached to one another so that rows of tubes are formed. Selected portions of the stem may be provided with holes or other opening devices to control the flow of exhaust gas through the formed tube.

The muffler of US Pat. No. 4,700,806 further includes a pair of outer shells. In the embodiments described above, the outer shell has a peripheral portion and a fold connecting the separated portions on the peripheral portion. The fold line is formed in substantially continuous contact with the inner plate between the peripheral portions of the outer shell. Therefore, the folds shown in US Pat. No. 4,700,806 effectively form a baffle that allows multiple chambers to be formed by the outer shell. US Patent No. 470080
The location of the fold shown in No. 6 is chosen depending on the volume of the chamber required for the particular noise attenuation and exhaust gas flow characteristics.

Other improvements to stamped mufflers include U.S. Pat. No. 4,736,817; U.S. Pat.
No.

Mufflers made in accordance with the four US patents mentioned above have achieved considerable commercial success in a very short period of time. All of this commercial success relates to mufflers for native equipment where the number of mufflers of a particular type is sufficient to easily offset the cost associated with stamping. However, it is anticipated that there will be some cases where the volume of the muffler is small thereby increasing the price per muffler with respect to the four stamping dies required for the four stamped forming parts of the muffler. It is also anticipated that in some cases the exhaust gas flow may require correct uncomplicated acoustic articulation. For these cases, it would be desirable to have a muffler that can be manufactured with very low initial manufacturing costs and low material costs, yet still obtains the highly desirable advantages of a manufacturing process that is well suited for automation, while also reducing weight. It is well known that fuel efficiency and other aspects of engine performance can be improved. It is therefore desirable to obtain vehicle elements that are preferably lightweight.

It is therefore an object of the invention to obtain an exhaust muffler with a relatively small number of elements.An object of the invention of zero order is to obtain a very lightweight muffler and exhaust system. A further object of the invention is to obtain a muffler having stamped forming elements but with a low cost die. Yet another object of the invention is to provide a muffler that facilitates automation of welding of muffler elements. A further object of the invention is to obtain a muffler of unitary construction and having baffles integral with the outer shell for supporting the tubular elements of the muffler.

SUMMARY OF THE INVENTION The present invention is directed to an exhaust muffler having a pair of opposing outer shells each formed to define a plurality of chambers. The outer shell is formed by stamping or other known metal forming techniques. Each outer shell is positioned such that the peripheral portion formed to form the peripheral flange lies generally in a plane. The peripheral portions of the two formed outer shells are dimensioned to lie generally in conformity with each other, allowing the opposing peripheral portions to be securely attached to each other.

OPERATION The outer shell is formed to form at least one baffle fold extending between and joining a pair of spaced apart peripheral portions of the outer shell. The base of the baffle fold has a plurality of non-linear sections, at least some of which are sized to encircle and securely engage tubes within the muffler, as described below. The folds in the outer shell are placed in substantially congruent relation to each other such that a portion of the base of the baffle fold in one outer shell is in face-to-face contact with a corresponding portion of the base of the baffle fold in the other outer shell. Each outer shell has a plurality of baffle folds, with each fold in one outer shell generally matching a corresponding fold in the other outer shell. The base of each baffle fold in one outer shell contacts a corresponding portion of the base of each baffle fold in the other outer shell. The non-straight portions of the baffle folds may be of any shape, but are preferably approximately semi-circular or semi-cylindrical and sized to securely engage a generally cylindrical tube. Selected non-linear portions of the baffle folds provide communication between chambers. This is the dimension to control.

In particular, the non-straight portions of the baffle folds form stamped formed tubes.

The portion of the outer shell is further configured to engage at least one inlet vibe to the muffler and at least one outlet vibe from the muffler. The portions of the outer shells that engage the inlet and outlet vibes are generally contiguous with the peripheral portion of each outer shell and are generally semi-circular or semi-cylindrical or otherwise shaped to fit with the pipes.

The remainder of the outer shell forms a shape chosen to fit the available space on the vehicle.

At least one of the outer shells has a concave conforming region shaped to conform to convex structures on the vehicle.

Preferably, the outer shell is symmetrical to each other and a pair of interlockable outer shells can be formed from a set of stamped gouers.

The tubes in row 0, which has rows of tubes at least partially located within the muffler than muffler 1, are supported within the outer shell by non-straight portions of baffle folds formed within the outer shell.

At least selected tubes 4 are further supported by the inlet and outlet portions of the outer shell. Selected portions of each tube are provided with rows of holes, shutters, apertures, etc., from which exhaust gases enter and/or engrave into the expansion chamber partially formed by the baffle folds of the outer shell. I
It is possible to m. At least one tube within the muffler forms an articulation tube, the articulation tube being placed in communication with an enclosed low frequency resonant chamber formed in part by a baffle fold in the outer shell. At least one tube extends outwardly from the muffler to form a continuous, integral exhaust pipe or tailpipe. A continuous integral exhaust pipe and/or tail pipe located within the muffler is
It has holes, shutters, openings or other devices as described above through which exhaust gases can flow. a continuous exhaust pipe or tailpipe section located within the muffler; and/or
Or the part placed on the outside of the muffler may not be straight.

The outer shells snugly engage each other and around the tube of the muffler. Preferably, the outer shells are directly attached to each other at at least selected locations along the portions of the baffle folds that are in face-to-face contact with each other, such that the opposing baffle folds form a structurally and functionally integral baffle. are further integrated with their respective outer shells. Securely joining the outer shells to each other may be done by welding or by suitable mechanical joining devices.

Preferred fabrication and assembly methods include forming the outer shell inlet, outlet and baffle folds to align with selected non-linear portions. The outer shells are then joined together by welding or suitable mechanical interconnection devices. A tube having an open armor window or the like formed therein is inserted into the inlet or outlet opening far enough to be supported through the non-straight portion of the aligned baffle folds. The tube is then welded to the peripheral portion of the outer shell.

EMBODIMENTS A muffler according to the present invention is indicated generally at 10 in FIGS. 1-5. The muffler 10 has an outer shell 12.
14, which are formed from a one-piece sheet metal, such as aluminized steel, plated steel or stainless steel, or from a suitable non-metallic material. The muffler 10 further includes a tube 16
18, which are located at least partially within the muffler 10. Tube 16.18 as described here
extend integrally to the outside of the muffler 10 and form at least part of an exhaust pipe and a tail pipe, respectively. However, in particular embodiments, tubes 16,18 terminate generally near the periphery of muffler 10, thereby forming the inlet and outlet of the muffler. At least one separate exhaust pipe and tailpipe are coupled to the muffler inlet and outlet.

The portion of the tube 16.18 that is placed in the muffler 10 is provided with holes 20.22, which are selectively dimensioned to allow mm flow of exhaust gas from the tube 16.18, as described below. According to normal industrial practice, hole 2
0.22 can be replaced with other devices such as armored windows and openings that allow exhaust gas engraving.

The outer shells 12,14 are shown to be fairly symmetrical to each other. As a result, one stamping die can be used to form both outer shells 12,14. The use of identical outer shells 12,14 further simplifies inventory management. In many embodiments, however, a symmetrical shape of the outer shell 12.14 is not possible and must vary depending on the vehicle specification.

However, in these cases, the outer shell is
As shown in No. 61, it is possible to form by stamping using an insertion goo and a goo subset. Proper use of goo subsets and insert goues can considerably reduce the investment in dies for stamping outer shells of similar but different shapes.

Outer shell 12 has a generally flat flange 24 .

An arcuate inlet flange 26 and an arcuate outlet flange 28 extend away from the flat portion of the peripheral flange 24 and form the inlet and outlet portions of the muffler 10, as described below.

Outer shell 12 further includes baffle folds 30 joining separate portions of peripheral flange 24. In particular, the baffle fold 30 has a flat base 32.3436 and an arcuate portion 38.
．． 40. Flat part 3 of baffle fold 30
2.3436 is placed approximately in the same plane as the peripheral 7 flange 24. However, the arcuate portion 38.40 is dimensioned to extend from the face of the peripheral flange 24 and engage the tube 16.18 as described below.

The outer shell 12 is further characterized by defined chambers 42 , 44 , which extend from the plane formed by the peripheral flange 24 . The chambers 42, 44 have recessed portions 46, 4, respectively.
8, and these dimensions are approximately compatible with the shape of the convex structure on the vehicle on which the muffler 1G is mounted. The recesses 46 , 48 further serve to strengthen the chambers 42 , 44 , thereby reducing noise associated with vibrations of the outer shell 12 . However, in many embodiments of the muffler 10, the outer shell 12.14 is
A plurality of reinforcing grooves as shown in No. 9 are provided.

Outer shell 14 is generally symmetrical to outer shell 12, as shown in FIGS. 1-5. However, this symmetry of the outer shells 12,14 is not absolutely necessary and is not possible in many mufflers. The outer shell 14 is the outer shell 12
The peripheral flange 54 has a generally planar peripheral flange 54 dimensioned to be placed generally in conformity with the peripheral flange 24 of the outer shell 12. 26.
It is placed to match 28. Outer shell 14 further includes a baffle fold 60 formed by a generally flat portion 6264.66 and an arcuate portion 68.70. The flat portions 62, 64, 66 of the baffle fold 60 lie in the same plane as the flat peripheral flange 54 and the outer shell 12
is sized to be in face-to-face contact with the flat portions 32, 34, 36 of the baffle folds 30 of. Similarly, baffle crease 6
0 arcuate portion 68 , 70 is placed generally in line with the arcuate portion 3840 of the baffle fold 30 of the outer shell 12 .

Outer shell 14 further includes chambers 72 , 74 extending from peripheral flange 54 . In a typical muffler in which the chambers 72, 74 each have a concavely inwardly formed recessed portion 76, 78, it is not necessary to provide a mating portion on the opposing outer shell, but a mating recessed portion. The provision of 76, 78 contributes to the reinforcement of the outer shell 14 and allows the use of substantially identical goo subsets for the formation of the outer shell 12.14.

The muffler 1G is assembled into the shape shown in FIGS. 2 through 5 by first placing the exhaust pipe 16 and tail pipe 18 in the correct positions within the outer shell 14.

In particular, the exhaust pipe 16 is placed within the arcuate flange 56 and the arcuate portion 70 of the baffle fold 60 such that the row of holes 20 is substantially aligned with the chamber 72, and the extreme end 80 of the exhaust pipe 16 is positioned within the arcuate flange 56 of the baffle fold 60 and the arcuate portion 70. 74.

Similarly, the tailpipe 18 is mounted within the outlet 7 flange 58 and the arcuate portion 68 of the baffle fold 60. The row of holes 22 are placed overlying within the chamber 74 while the end 82 of the tail pipe 18 is placed within the chamber 72.

Outer shell 12 is then mounted to outer shell 14 such that peripheral flanges 24.54 respectively are in mating, facing relationship. In this direction, the inlet and outlet flanges 26, 28 of the outer shell 12 are connected to the exhaust pipe 16 and the tail pipe 1, respectively.
8 and engages with them. Moreover, outer shell 1
The arcuate portions 3840 of the baffle folds 30 in 2 generally surround and engage the tail pipe 18 and the exhaust pipe 16, respectively. In this assembled state, the flat portions 32, 34.36 of the baffle fold 30 are in substantially face-to-face contact with the flat portions 62, 64.66 of the baffle fold 60, respectively. juxtaposed flat parts 32, 34, 36 and 62, 64, 66
are each firmly connected to one another, for example by spot welding.

In a preferred embodiment, multiple pairs of juxtaposed flat portions 32,3
Multiple spot welds are used to interconnect 4.36 and 62.64.66.

The assembly is completed by securely joining the outer shell 12.14 to each other around the respective peripheral flanges 24.54. The joining of the zero peripheral flanges 24.54 is preferably by welding, such as seam welding. .5
4 and flat parts 32, 34.36 and 62.6466
Since the metal is twice as thick, welding is relatively easy. The exhaust pipe 16 is then securely welded to the inlet flanges 26, 56, and the tail pipe 18 is similarly welded to the outlet flange 28.58. Welding the exhaust and tail pipes 16, 18 to the rest of the muffler 10 is easily accomplished by robotic welding equipment.

As an alternative to the above assembly process, the outer shell 12 may optionally be
．． 14, exhaust pipe 16 and tail pipe 18 can be firmly connected together before placing them therein. The exhaust pipes 16 can then be slid between the inlet flanges 26.56 a sufficient distance to be properly supported by the arches 40.70 of the baffle folds 30.60, respectively. Similarly, the tail pipe 18 is connected to the outlet flange 2.
8.58 and can be slid a sufficient distance to be supported by the arches 38.68 of the baffle folds 30.60, respectively.

The exhaust pipe 16 and the tail pipe 18 are connected to an inlet flange 26.56 and an outlet flange 28.5, for example by welding.
8 is tightly coupled. According to this embodiment, the exhaust pipe 16 and the tail pipe 18 are supported by the fold line 30.60 and are not mechanically connected thereto; therefore, the exhaust pipe 16 and the tail pipe 18 are
It can easily expand in response to the heat generated by the exhaust gas flow through it.

It is emphasized that the muffler 10, shown in detail in FIGS. 2-5, provides a lightweight, extremely simple construction, a considerable amount of metal, and a very simple fabrication process.

In particular, unlike many prior art mufflers, the muffler 10 does not have a flat metal plate section extending between the tube and the peripheral portion of the muffler; rather, the tube is connected to the peripheral portion of the muffler everywhere except at the inlet and outlet. It is an area structure completely separated from the surrounding area. Moreover, unlike some prior art mufflers, the muffler shown specifically in FIG.
．． 14 and an integral baffle fold 30.60. Therefore, the installation of the baffle fold 30.60 integral with the outer shell 12.14 eliminates the need to provide a separate baffle device as used in prior art mufflers with tubular inner elements. This greatly reduces the number of mufflers and makes muffler assembly extremely easy. Additionally, the secure attachment of opposing baffle folds 30,60 to each other contributes to the muffler's backfire resistance.

An alternative, slightly more complex muffler 90 is shown in FIGS. 6 and 7. The muffler 90 has an opposing outer shell 9
2.94 exhaust pipe 96 and tail pipe 98. The outer shell 92 includes a generally flat peripheral flange 10 having an arched-in loft flange 102 and an arched-out loft flange 104.
0. The outer shell 92 further includes a generally centrally located engraving chamber 106 and a low frequency resonant chamber 108.
, 110. Baffle folds 112 and 114 separate engraving chamber 106 from low frequency resonant chambers 108 and 110, respectively. Fold lines 112, 114 have flat portions 116, 118, respectively, which lie generally in the same plane as peripheral flange 10G.

Additionally, as in the previous embodiment, folds 112 and 114 are provided with arcuate portions for engaging exhaust pipe 96 and tail pipe 98, respectively.

The outer shell 94 has a generally flat peripheral flange 12 having a 9-shaped inlet flange 122 and a 9-shaped outlet flange 124.
It has G. A centrally located engraving chamber 126 and low frequency resonant chambers 128, 130 extend from the peripheral flange 120. The m-membrane chamber 126 is separated from the low frequency resonant chambers 128 and 130 by baffle folds 132 and 134, respectively. As best seen in FIG.
, 138. - Formed by 14G. The arcuate portion is placed within the fold 132 and connects the exhaust pipe 96 and the tail pipe 9.
8 and extends from the plane formed by the peripheral flange 120. Similarly, and as shown in FIG.
and a peripheral flange 12 for supporting the tail pipe 98.
and an arcuate portion extending from the G plane. outer shell 94
The baffle folds 132,134 of are positioned to generally match the baffle folds 112,114 of the outer shell 92. Therefore, engraving chamber 126 of outer shell 94 generally matches engraving chamber 106 of outer shell 92. Additionally, low frequency resonant chambers 128, 130 of outer shell 94 match corresponding low frequency resonant chambers 108, 110 of outer shell 92.

The exhaust pipe 96 has a row of holes 152 that lie across the engraving chambers 106,126. Low frequency resonance chamber 1
Exhaust pipe 9 placed to lie within 10,130
6 is free of holes and bent to achieve a length that properly attenuates the selected narrow range of low frequency noise = the end 154 of the exhaust pipe 96 is connected to the low frequency resonance chamber 1
10,130.

Similarly, the tailpipe 98 is provided with a row of holes 156 that lie across the engraving chambers 106,126.

The portion of the tail pipe 98 that is in line with 1i1108.128 at both low frequencies is substantially hole-free and substantially straight. The end 158 of the tail pipe 98 is connected to the low frequency resonance chamber 1.
08,128.

In the embodiment of the muffler clearly shown in FIG. 7, it can be seen that the exhaust pipe 96 and tailpipe 98 have a curved curvature at the entrance to the muffler 90 on the outside of the muffler.

The particular direction of curvature in exhaust pipe 96 and tailpipe 98 depends on the shape of the available space underneath the vehicle.

The muffler 90 is assembled in substantially the same manner as the muffler 10 described above. In their assembled state, the outer shells 92,94 are securely joined together around the peripheral flanges 100,120 at the flat portions of the baffle folds 112,114.

In this embodiment, baffle fold 112j32 functions as an integral baffle separating engraving chamber 106,126 from low frequency resonant chamber 108,128. Similarly, baffle folds 114, 134 function as integral baffles to separate engraving chambers 106, 126 from low frequency resonant chambers 110, 130. As mentioned in the previous embodiment, each baffle is integral with the rest of the outer shell 92,94, thereby making the muffler 90 considerably simpler than prior art mufflers having separate baffles. .

In the assembled muffler 90, the exhaust pipes 196 terminate in low frequency resonant chambers 110, 130 and function as articulating tubes that attenuate the low frequency range of noise in a fairly narrow manner. The specific frequency is determined by the volume defined by the low frequency resonant chambers 110, 130, by the cross-sectional area of the bis 196 and by the hole 15.
2 and the end 154 of the exhaust pipe. Similarly, the end of tailpipe 98 functions as a tuning tube leading into low frequency resonant chambers 108,128. The exhaust gas passes through the exhaust pipe 96 to the engraving room 10.
6,126 through holes 152. Exhaust gas flow continues through holes 156 in tailpipe 98; the volume of exhaust gas flow is between exhaust pipe 96 and tailpipe 98.
Determine the cross-sectional area of and the total area required for the upper holes 152 and 156. In certain embodiments, shapes other than circular holes 152, 156 may be desirable, such as armored windows or large openings.

Another alternative muffler is shown generally at 2 in Figures 8 and 9.
It is indicated by 00. A side view of muffler 200 is almost the same as the side view of muffler 90 shown in FIG. In particular, the muffler 200 includes first and second outer shells 202, 204, an exhaust pipe 206, and a tail pipe 208. For ease of explanation, assume that the outer shells 202 and 204 are substantially identical and symmetrical about two orthogonal axes. However, in many embodiments of mufflers, this symmetry is significantly hampered by the shape of the available space envelope on the vehicle.

Referring to FIG. 9, the outer shell 204 is stamped to form a generally planar peripheral flange 210 extending from the generally semi-cylindrical inlet and outlet grooves 209;
211 is extended. Chambers 212, 214, 216 are also formed extending from the face of the peripheral flange.

As in the embodiments described above, the volumes of the chambers 212, 214, 216 largely depend on the exhaust flow and noise characteristics of the engine, and the shapes of the side chambers 212, 214, 216 depend on the shape of the space available on the vehicle. Ru. The chambers 212, 214 are separated from each other by a baffle fold 218, while the chambers 214, 2
16 are separated from each other by baffle folds 220.

Baffle fold 218 includes generally flat portions 222, 224, 22 that lie generally in the same plane as peripheral flange 210.
It is characterized by having an angle of 6°228. Baffle folds 218 further include uneven portions 230, 232, 234
It is characterized by having the following. As shown in FIG. 9, the uneven portions 23◇, 232 of the baffle fold 218 are placed on either side of the uneven portion 234, respectively.

Baffle folds 220 are generally flat portions 242, 244
246.248 and uneven parts 250, 252, 25
4. Unflat part 250
．． 252 are placed on each side of the uneven portion 254. Additionally, the uneven portion 250 is the uneven portion 230
and the outlet groove 211, while the uneven portion 252 is substantially colinear with the uneven portion 232 and the inlet beam 209. Moreover, the uneven portions 230, 250 and the exit edge 211 have approximately the same dimensions,
In the exemplary embodiment, the uneven portions 230, 232, 250, 252 and the inlet and outlet grooves 269, 211 have approximately the same size and shape. It is cylindrical and forms a cross section that approximately corresponds to the external dimensions of the exhaust pipe 206 and tail pipe 208. Unflat portion 234.
252 is the uneven portion 230, 232, 250, 2
52 is shown in cross section. However, the relative dimensions of the uneven portion depend solely on the exhaust flow and noise characteristics of the engine to which the muffler is coupled.

Exhaust vibe 206 is generally straight within muffler 200 and extends to a location external to muffler 200. exhaust pipe 20
The outer portion of the exhaust pipe 206 may be straight or non-straight depending on the requirements of the exhaust system, and the exhaust pipe 206 has an end 258 that lies within the chamber 216.

The exhaust pipe 206 further includes an end 25 of the exhaust pipe 206.
8 and a row of holes 260 located at selected locations along and inwardly spaced from the hole. The total area enclosed by holes 250 is selected according to the noise attenuation requirements of muffler 200. Hole 260 is positioned overlying within chamber 214 . Similarly, tail vibe 208 has an end 262 that lies within chamber 212 .

The tailpipe 208 further has a row of holes 262 that lie within the chamber 214 of the muffler 20◇.

As mentioned above, outer shell 202 shown in FIG. 8 is substantially identical to outer shell 204. However, the outer shell 20
Differences between 2,204 are possible, and the respective shape is determined by the space availability of the vehicle. However, in many cases, the baffle crease 218 of the outer shell 204,
220 is positioned to generally match a corresponding baffle crease in outer shell 202. Additionally, outer shell 202
Preferably, the baffle fold of has a non-straight portion positioned to engage the exhaust vibe 2◇6 and the tailpipe 208.

The muffler 200 first extends the outer shells 202, 204 around their peripheral flanges, preferably at the baffle crease 218.
．． 220 are assembled by attaching them together at opposite flat portions. The inlet groove 209 of outer shell 2◇4 and the opposing inlet groove of outer shell 202 and the matching outlet grooves of FIG. 8 form the outlet from the muffler. outer shell 2
A strong connection between 02 and 204 is achieved by welding or by a suitable mechanical interconnection, such as shirring or rolling.

The exhaust pipe 206 is then slid axially through the inlet and through the non-straight portion 232252 of the outer shell 204 and the correspondingly matched non-straight portion of the baffle fold of the outer shell 202. In particular, the axial movement of the exhaust pipe 206 is caused by the axial movement of the exhaust pipe 206
in chamber 216 and hole 260 in chamber 214.

Similarly, tailpipe 208 is inserted axially into the outlet of muffler 200 through non-linear portions 230, 250 of baffle folds 218, 220, respectively, and corresponding non-linear portions of outer shell 202. In particular, insertion of the tailpipe 208 into the muffler 20G involves placing the end 262 of the tailpipe 208 into the chamber 212 and into the hole 264.
is made sufficiently to place the inside of the chamber 214.

The opposite outer ends of exhaust bi 1206 and tailpipe 208 are then suitably coupled to other portions of the exhaust system.

As best shown in FIG. 9, the flow enabled by muffler 200 is similar to that of a well-known three-component muffler made of a conventional wrapped outer shell, at least three tubes, and a separate row of baffles. Very similar. In particular, a portion of the exhaust gas flowing through exhaust pipe 206 exits into chamber 214 through hole 260 . The remaining exhaust gas enters flow chamber 216 at the end of exhaust bypass 1206. Gas entering chamber 216 is directed to non-straight portions 25 of baffle folds 220.
4. Flows through a forming tube formed by a corresponding non-linear portion of the baffle fold in outer shell 202. Gas entering chamber 214 through hole 260 or from chamber 216 mixes and flows directly into hole 264 and/or between non-straight portion 234 of baffle fold 218 of outer shell 2◇4 and corresponding non-straight portion of shell 202. It flows through the forming tube that is formed.

Ice exhaust gas flowing through the forming tube formed by the non-straight portion 234 and the corresponding portion of the outer shell 202 continues to flow into the end 262 of the tailpipe 208 toward the outlet of the exhaust system. Gas entering tailpipe 208 at end 262 mixes with gas entering tailpipe 208 at hole 264 . The relative mixing of exhaust gases within the muffler 200 is achieved through careful selection of the cross-sectional areas of the holes 260, 264 and the non-straight portions 234 of the outer shell 204.
254 and a correspondingly mating non-linear portion of outer shell 202 can be controlled by the relative selection of the cross-sectional dimensions of the forming tube formed by 254 and the corresponding conforming non-linear portion of outer shell 202.

The muffler 200 shown in FIGS. 8 and 9 provides a desirable and widely accepted gas flow regime with only four elements.

This contrasts sharply with prior art wrapped outer shell mufflers which require a minimum of nine parts to achieve this same flow regime.

Although the fully stamped mufflers described above also achieve this same flow pattern with four parts, these often result in heavier mufflers, have a somewhat higher initial capital cost due to the stamping die, and Muffler 2 shown in Figures 8 and 9
It can be seen that the gas flow regime of the 00 can be significantly altered by having the forming tube only on one of the matched pairs of buckle folds. 250.252 can have a continuous flat portion. Baffle crease 2
The baffle folds of outer shell 202 that match 20 may be substantially identical in shape; in this embodiment, the portion of exhaust pipe 206 between hole 260 and end 258 forms a tuning tube. Chamber 216 therefore forms a low frequency resonant chamber. All exhaust gas flowing through exhaust pipe 206 is forced into chamber 214 through hole 260. A portion of this gas flows directly into tailpipe 208 through hole 264, while another portion of the exhaust gas flows through baffle crease 2.
It flows into chamber 212 through a tube formed in part by non-straight portion 234 of 18 . This gas continues to flow from chamber 212 into end 262 of tailpipe 208 . The relative proportions of exhaust gas taking these alternative paths to tailpipe 208 can be controlled by selecting the cross-sectional areas of non-straight portion 234 and hole 264, respectively.

[Effects of the Invention] As described above, according to the present invention, the muffler is provided with a pair of outer shells and a pair of pipes.

Each of the outer shells has a peripheral flange and a plurality of chambers extending from the peripheral flange. The chambers are separated from each other by buckle folds, and the baffle folds of each outer shell have juxtaposed portions that generally coincide with each other and contact each other in a generally face-to-face relationship.

The pipes in the muffler have holes, shutters, openings, etc. to control the engraving of future exhaust gases. Devices such as openings are placed at selected locations with respect to the chamber formed within the muffler. The pipe within the muffler extends continuously beyond the muffler and forms an integral part of the exhaust pipe and tailpipe of the exhaust system.

The outer shell is assembled and the pipe is inserted axially into the assembled outer shell. The baffle folds effectively separate the chambers and are integral with the rest of the outer shell, further contributing to an efficient welding process and backfire resistance.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view of a muffler according to the present invention, FIG. 2 is a side view of the assembled muffler of FIG.
A cross-sectional view taken along line 3-3 in the figure, Figure 4 is 1a4 in Figure 2.
5 is a sectional view taken along line 5-5 in FIG. 3; FIG. 6 is a side view of another embodiment of the muffler according to the invention; FIG. - sectional view at 7,
FIG. 8 is an end view of a third embodiment of the muffler according to the present invention, and FIG. 9 is a sectional view taken at a9--9 in FIG. 8. 10...Muffler, 12.14...Outer shell, 16
．． 18...tube, 20.22...hole, 24,2
6.28...Flange, 3◇...Fold, 32,3
4.36... base, 38.40... arched part, 42.
44... Chamber, \46.48... Concave part, 54.56
．． 58...Flange, 60...Fold line, 62, 64
．． 66...part, 68.70...end, 72.74
...Chamber, 76, 78...Concave part, 80.82...
End, 90...Muffler, 92.94-...Outer shell, 96.98...Pipe, 100.102.104-
...Flange, 106.108.110...Chamber, 11
2.114...fold, 116.118...part,
120.122゜124...Flange, 126.1
28.130...room, 132,134...fold, 1
36.138.140...part, 146.148.1
50... portion, 152... hole, 154... end,
156... Hole, 158... End, 200... Muffler, 202, 204... Outer shell, 206° 208
...Pipe, 21◇...Flange, 209,211
...Groove, 212.214,216...Room, 218,
220...Fold line, 222, 224226, 228.
230.232.234.242.244.246.2
48.250.252. 254... portion, 258... end, 260... hole, 262... end, 264... hole.

Claims (11)

[Claims] (1) A lightweight exhaust muffler having a pair of generally tubular pipes having a hole arrangement extending therethrough to permit the flow of exhaust gases, and a pair of formed outer shells, each of the outer shells having a peripheral portions of the outer shells, the peripheral portions of the outer shells being securely coupled together, each of the outer shells further having a plurality of chambers formed therein and extending from the peripheral portions thereof; Each said chamber is integral with said respective outer shell and separated from one another by a baffle fold extending between and joining spaced apart points on said peripheral portion of said outer shell, said baffle fold of said outer shell substantially congruent with each other and formed in the at least one congruent fold with the portion surrounding and engaging the pipe of the muffler, and separated from the congruent fold by the baffle fold; an exhaust muffler having a non-straight section forming a forming tube extending between the separated chambers of the muffler. (2) The muffler according to claim 1, wherein the matching baffle fold portions are mounted in face-to-face contact with each other. 3. The exhaust muffler of claim 1, wherein each of said outer shells has three chambers formed therein and two baffle folds; The exhaust muffler wherein the chambers are separated from each other by said baffle fold, said non-straight portion being located within at least one said baffle fold, providing communication between at least two said chambers. 4. The exhaust muffler of claim 1, wherein said outer shell is securely welded in facing relationship to each other at a plurality of locations along each of said baffle folds. (5) The exhaust muffler according to claim 1, wherein each of the pipes has an integral structure. (6) The exhaust muffler according to claim 5, wherein at least one of the pipes extends integrally to the outside of the muffler. (7) The exhaust muffler according to claim 6, wherein a portion of the pipe placed outside the muffler has a non-linear shape. (8) The exhaust muffler according to claim 6, wherein the pipe portion in the muffler has a linear shape. (9) A lightweight exhaust muffler having a pair of pipes of monolithic construction with opposing ends, each of said pipes extending through the pipe at a distance from said end to permit flow of exhaust gas therethrough. and a pair of opposing outer shells tightly coupled to each other, each of the outer shells integrally defining a peripheral flange and a plurality of chambers extending from the peripheral flange. and wherein the chambers are integrally formed within each of the outer shells and are separated from each other by baffle folds extending between and connecting spaced apart points on the peripheral flanges, and the chambers are integrally formed in each of the outer shells and separated from each other by baffle folds extending between and connecting spaced apart points on the peripheral flanges, The respective baffle folds of the baffle folds generally coincide with each other, each of the baffle folds having a flat portion in face-to-face contact with a flat portion of the mating baffle fold, and the baffle fold further extending from the flat portion. an extending uneven portion, a selected uneven portion engaging and supporting the pipe of the muffler, and at least one of the uneven portions being spaced from the pipe and extending between the two chambers; The exhaust muffler forms a tube that connects between the exhaust muffler. 10. The exhaust muffler of claim 9, wherein each of said outer shells is formed to define three chambers and two baffle folds. 11. The exhaust muffler of claim 10, wherein each of said baffle folds has one of said non-straight portions spaced apart from said pipe.