US2150811A - Muffler - Google Patents

Description

Mal'Ch 14, 1939- G. c. sTARKwEATHr-:R E-r Al. 2,150,811

MUFFLER Filed March ll0, 1937 3 Sheets-.Sheet Q Ibm, K\

March 14, 19392 (g.l Cl STARKWEATER ET AL 2,150,811

MUFFLER 19437 5 Sheets-sham 2 Filed March l0,

Q m, mw la um O um w m @hw M @H 0 0\O 0 O 0000 o 0000 @0000 nH Q@Swo 0000 MMO www r@ wr Q@ m% 1Q MUFFLER Filed March 10, 1937 5 sheets-sheet 3 G. C. STARKWEATHER ET ALy March 14, 1939.

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Patented Mar. 14, 1939 PATENT JoFFlcla- 2.150,81; Homan.

een. c. stu-kmh, Kenmare, ma Lucien L. Haas, Builalo, N. Y., assignors to Buil'alo Pressed Steel Company, Buil'alo, N. Y.

ppueauon Much 1|,

This invention' relates to improvements in muillers or silencers for use in silencing the noises of the exhaust of an internal combustion engine.

One of the objects of this invention is to provide an improved mulller of the type in which the gases are caused by bailles or the like t0 change their direction of ilow while passing through the muiller, with a resonator chamber. Another object of the invention is to provide a muilier of this type in which a chamber is provided into which surges or` peaks of pressure waves may pass to provide a more uniform ilow of gases through other parts of the mumer.

Another object of the invention is to provide a muiiier of this type with a resonator chamber which acts upon the sound waves to reduce noise by destructive interference.

Other objects of this invention will appear from the following description and claims.

In the accompanying drawings:

Fig. 1 is a longitudinal central sectional view of a muilier embodying this invention.

FigsjZ and 3 are transverse sections thereof respectively on lines 2-2 and 3 3, Fig. l.

Fig. 4 is a fragmentary longitudinal sectional elevation of one end of a muiller oi' slightly modied construction.

Fig. 5 is a longitudinal central sectional view of a muiler of modified construction.

Fig. 6 is a transverse sectional view thereof, on line 6 5, Fig. 5.

Fig. 7 is a, fragmentary longitudinal central sectional view of one end of the muiiler shown in Fig. 5, with a slight modication.

Fig. 8 is a longitudinal central sectional view of a muiiler of still another modified construction.

Figs. 9 and l0 are transverse sectional views respectively on lines 9 9 and lil-l0, Fig. 8.

Fig. l1 is a fragmentary longitudinal central sectional view of a portion of the muilier'shown' in Fig. 8, with a slight modiilcation.

We have found that if a mumer of the type in which the gases in passing through the same are caused by bailles, shells or the like,'to change their direction of ow a number of times, is provided with a resonator chamber, superior results can be obtained not only insofar as the silencing of sound waves is concerned, but also in that the resistance to the ilow of gases through the muliler will be reduced by the use of such resonator chamber which acts as an equalizing chamber for the pressure impulses, so that the back pressure heretofore produced by muillers of this type is reduced.

1932, Serial No. 130,158

We have illustrated by way of example several forms of mumers of thistype embodying our invention and it will be understood that the muiilers shown are merely illustrative of our invention and that it is not intended to limit this invention to the particular constructions shown.

In Fig. 1, a muiller is shown having a suitable housing or enclosure which may, for example.

include an outer shell l5 and end heads IB and lo I'I. The head I8 is provided with a tubular extension or duct I8 adapted to receive an exhaust pipe I9 and the other head I1 is provided with a similar duct or tubular portion 20 through which the gases are discharged i'rom the muiller and to which the usual tail pipe (not shown) may be secured. The mumer includes an inner shell or conduit 22 and a pair of intermediate shells 23 and 24, which are spaced from each other and from the conduit 22 and outer shell II to form spaces or chambers 25, 28 and 21.

The conduit and shells may be supported within the muiller in any suitable or desired manner. In the particular construction shown, a stepped cone or supporting member is provided which has a substantially cylindrical outer portion 30 adapted to it Within an annular cylindrical part 3| of the inlet head lli. This cylindrical part 30 of the shell support also is arranged to telescope ywithin the adjacent end of the intermediate shell 23 to support the same. The shell support has another cylindrical portion or shoulder 32 of smaller diameter which is adapted to telescope within the adjacent end oi' the inner conduit 22. The shell support may, if desired, be provided with an additional cylindrical portion 33 of still smaller diameter which extends into the conduit -22 and which may receive the inner end of the exhaust pipe i9 as shown in Fig. 1. At the other end of the muiiler, the discharge head I1 is pro- 40 vided with a cylindrical portion or shoulder 35 within which the shell 23 may nt. The other intermediate shell 24 of larger diameter may be supported in the muiller in any suitable manner, for example, by providing the opposite ends thereof with inwardly pressed projections or parts 31 which rest against and which may be welded to the intermediate shell 23 as indicated at 3l. Any other means for securing the shells in correct relation to each other and to the muiller may, of course, be employed in place of those shown, and the connecting or telescoping parts of shells, heads, bailles and shell supports may be welded together or otherwise secured, or may be lett to slide relatively to each other to compensate for expanison and contraction due to unequal heating of different parts oi' the muiher dur ing use. i

The other or rear end oi the conduit 22 may be supported in correct relation to the inner lshell by means of a baille 40 having an outer cylindrical portion 4| which may be welded or otherwise secured to the shell 22 and having a second cylindrical portion 42 of smaller diameter which may telescope into the other end of the conduit 22. This baule includes a transverse wall 43 which closes the rear end of the inner conduit 22.

The inner conduit is provided with a discharge opening; which may be in the form ci a series oi-apertures 45 through which the gases may flow from the inner shell 22 into the chamber 25 between this conduit and the intermediate shell 23. The intermediate shell 23 is provided f l with an opening or apertures 48, preferably 1ocated at a distance from the apertures of the conduit 22, for example,near the inlet head IB of the mulder, and the gases and sound waves may, consequently, be discharged through these apertures from the chamber 25 into the chamber 28. The intermediate shell 23 near the discharge end of the muiiier and beyond the baille "42 is provided with a series oi apertures 41 through which the gases iiow from the chamber 26 into the chamber 48 formed at the rear end o! the shell 2l between the baille 40 and the head I1. The intermediate shell 24 is also provided with means for communicating with the outer chamber 21 of the mumer and any suitable means for this purpose may be employed, such for example as a series of apertures 49.

In the operation of the muiiler, the exhaust gases from the engine are discharged through the exhaust pipe Il, into the inner conduit or shell 22 inthe form of a series of pressure pulsations Vor waves, which are accompanied with sound waves. The gases pass to near the end of the shell 22 and are then discharged through the apertm'es 45 into the chamber 25, from which they pass through the apertures 46 into the chamber 2l. During the crest or peak of a pressure wave, some of the gases pass into the chamber 26 through the apertures 4! into the outer or resonatorchamber. Aiterapressurepeakhaspassed out of the chamber 26, some of the accumulated Vgas in the resonator and equalizing chamber 21 'is discharged back into the chamber 26. Sound wavesalso pass through these apertures 49 into the r and equalizlng chamber and then back through the same aperture into the chamber 2l, at which time they will be out of phase with similar sound waves in the chamber 28. The gases and any remaining or modified sound waves then continue to ow lengthwise into the charnber 2i through the apertures 41 in the chamber 4I from which they are discharged from the mullet. Y

The resonator chamber 21 in addition to its silencing elect upon the sound waves, thus also serves a very useful purpose of equalizing the flow of gases so that when a surge of gas enters the chamber 2i, following the opening of an `exhaust valve, aportion of this gas will enter into the chamber 21 and will again be discharged into the chamber 2C during the trough of the pressure wave or impulse. This results in a steady iiow o! 'gas through the passage or chamber 2l and through the apertures 41, chamber 48, and through the tail pipe. This steady flow results in a material reduction in the resistance to the tlow, and consequently, results in a reduction in the back pressure of the muiher, as well as producing a very excellent silencing of' the exhaust noises.

In- Flg. 4 is shown an end of a muffler similar to the one shown in Figs. l to 3 inclusive; except for the following changes: The muffler shown in Fig. 4 has a second intermediate shell 52 correspending to the shell 24 oi the muilier shown in Figs. 1 to 3. The ends of the shell 52 are also provided with depressions or inwardly pressed portions 53 corresponding to the parts 31 oi the shell 24, forming portions or channels 54. 'Ihe muiiler shown in Fig 4 differs from that shown in Figs. 1 to 3 in that the end of the shell 52 is spaced from the head IB. so that the channels 54 are utilized to carry the gases and sound waves from the chamber 55 formed between the two intermediate shells 23 and 52 into the outer resonance chamber 5B formed between the outer shell l5 and the intermediate shell 52. The channels 54` consequently, form bottle necks for the resonator chamber 5B, and the wave lengths to which the chambers respond can be varied by changing the cross section and length oi the bottle necks. Inconnection with this construction, it is also possible to divide the outer space between the shells 52 and i5 into two resonator chambers 56 and 51 by means oi an annular transverse baille 58. 'I'his baille can, consequent ly, be moved lengthwise oi the space between the shells |5'and 52 so that the chamber 56 may be tuned in accordance with the particular sound waves which it is desired to silence by destructive interference. Obviously, if two resonator chambers are desired', the opposite Vend of the intermediate shell 52 may be similarly formed to communicate with the chamber 51. The operation of this muiiler is similar to that oi the muilier shown in Figs. 1 to 3.

The modified form of our invention shown in Figs. 5 and 6, includes an outer shell 60 which with the heads Si and 62 forms an enclosure or housing for the muiiier. The heads shown are similar in construction to those described in connection with the muiiiers shown in Figs. 1 to i, to form tubular extensions or ducts for connection with exhaust and tail pipes. 'I'he muiiler is also provided with a supporting member E3 in the form of a stepped cone to which an inner shell or conduit 64 is secured. In this construction, however, only one intermediate shell 65 is employed which is suitably welded or otherwise secured to a cylindrical shoulder or part 6G of the inlet head El, and the supporting member 63 has an outer cylindrical portion 61 welded or otherwise secured to the inner face of the intermediate shell 65. The other end of the intermediate shell may be telescopically arranged within a. substantially cylindrical shoulder B8 of the head 62 and welded thereto.

'Ihe end of the inner shell or conduit remote from the gas receiving end is closed and supported from the intermediate shell 65 by means of a baille member 1U, the outer flange or portion oi! which may be welded to the intermediate shell 6I and the middle portion 1l of which telescopes within the end of the inner conduit. The inner conduit may also be provided with a restriction or contracting member which may be in the form of a sleeve 12 having an outer substantially cylindrical portion 13 welded to the inner face of the conduit 84 and having an annular portion 14 of reduced diameter. A restriction or obstruction to gas flow of any other suitable construction may be employed in the conduit G4, or the restriction may be omitted, if desired.

ing a resonator and pressure equalizing chamber 8| which communicates with the space between the conduit 64 and intermediate shell by means of a series o! holesl or apertures 82 in the intermediate shell 65. At the other side of the baille 80 is formed a chamber or passage 88 which receives gases from the space between the conduit and intermediate shell through a series of apertures 84 in the intermediate shell located in front of the baille 10 and the gases and sound waves pass out of the chamber 83 through another series of holes or apertures 85 located in rear of the baille 10. The gases thus pass into a chamber 86 arranged within the intermediate shell between the baille 10 and atransverse baille 81 having a restricted opening 88 which may form` a support for the inner end of the tail pipe, or

which may form with the end head 62 a small expansion chamber 89 in case thetail pipe does not extend inwardly beyond the inner end of. the tubular extension or duct 90 of the head 6M Holes or apertures 15, 16 and 82 in the inner conduit and intermediate shell may, ii' desired, be provided with louvers or deilecting members 92, as clearly shown in Fig. 6, so that the gases and sound waves discharged through these apertures will be discharged in directions substantially tangential to the conduit and shell in which the apertures are formed.

In Fig. 7, we have illustrated a slight -modiilcation of the construction shown ln Fig. 5, by replacing the baille 88 shown in Fig. 5 by a bafiie 94 which has a series of apertures 95 therein. Consequently, a chamber 9.6 is formed between the baille 94 and the end head 62, which serves as an expansion chamber, if the tail pipe 91 of the muiiler extends from the duct 90 into the central opening 98 of the baille 94.

In the operation of the muffler shownn Figs. 5 to 7, some of the gases and sound waves passing into the inner conduit 64, will discharge throughv openings 15 therein while other gases 'pass through the restriction 14 and then through openings 16 and these gas pulsations and sound waves will, consequently, be somewhat out of phase with those that have passed through the openings 15. A further silencing of sound waves and equallzing-of gas flow results from the passage of sound Waves and gases into the resonator chamber 8|. Peaks of gas pressure waves or impulses which enter into the chamber 8| are then discharged from this chamber during the troughs or low pressure periods, resulting in a more uniform flow of gases through the aper- Ctures 64, the chamber 83 andinto the chamber 86. From the chamber 86 further expansion of gases and silencing of sound waves is effected by means of the chambers 89 or 96, and consequently, there will be a comparatively uniform ow of exhaust gases through the tail pipe 91. 'I'he sound waves which have passed hito the muiiler will have been so interfered with and reduced by the'resonator chamber 8| and other parts of the muiiler that the gas discharged from the end of the tail pipe will be comparatively free from audible sound waves.

In Figs. 8 to 10 inclusive, we have shown another modifled form of muiller, which is very similar to that shown in Figs. 5 to 7. This muiiler includes an outer shell and end heads 0| |02, which are provided with annular shoulders to support the ends of an intermediate shell |03. The inner shell or conduit |04- ls supported vwithin the intermediate shell |03 by means of baiiies I 05,and |06, the baille |06 closing the end of the inner conduit or shell |04 and the baille being provided with an aperture |01 which is preferably of smaller diameter than the internal diameter of the conduit |04. 'Ihe inner shell or conduit |04 is also provided with a restriction or contraction' |08 similar to that described in connection with Figs. 5 and 6 and acting in a similar manner in connection with apertures |09 and ||0 located before and. behind the restriction |08. An annular baille is provided between the intermediate and outer shells forming a resonator and expansion chamber ||2 into which gases and sound waves may enter through a series of apertures ||4 which are formed in the intermediate shell aheadv of the baille |05. The intermediate shell is also provided with apertures 5 communicating with a chamber IIB formed in rear of the annular baille and the gases and sound waves pass out of the chamber I|6 through a series of openings or Aapertures ||1 into a chamber ||8 from which they are discharged from the muiiler. The apertures |09, ||0 and ||4 may be provided with louvers or deilecting parts 9, as shown in Figs. 9 and 10.

In the operation of this mulller, gases and sound waves entering the muiiler through the inlet head |0| enter into the expansion chamber |20 and the peaks or crests of pressure impulses vor waves, together with sound waves immediately enter through the apertures ||4 into the resonator and pressure equalizing chamber l2. The reduced pressure waves or impulses together with sound waves which have been materially reduced by destructive interference from sound waves discharged from the resonator chamber |2 then pass into the conduit |04, the reduced opening |01 of the baille |05 serving to hold back to a limited extent the gases and sound waves in the chamber |20 to obtain the full benefit of the resonator and equalizing chamber I2.. A part of the gas pressure impulses and sound Waves pass out of thev openings |09 and other gas impulses and sound waves will pass out of apertures ||0 after travelling through the restriction |08, and will be somewhat out of phase with those discharged from the apertures |09. This results in an equalizing of the flow of gases as they pass through the apertures ||5 and also in a material reduction oi' noises, ilrst by the resonator chamber |I2 and then by the action of the other parts of the mullier which have been described. FurvH6 and H8.

In Fig. 11, there is shown a baille |25 arranged between the intermediate shell |03 and the inner shell or conduit |04, which differs from the baille |05 only in that there are provided in the transverse wall of the outer portion of the baille a series of apertures |26, through which some gas and sound waves may pass directly from the chamber |20 into the chamber or passage formed between the inner conduit |04 and the intermediate shell |03. For certain types of engines, these apertures assist materially in taking out sound waves of certain frequencies in that there will be discharged into the space between the inner conduit and intermediate shell some gas impulses and sound waves,which will be out of phase with impulses and sound waves entering through the in the case o! gas pressure impulses, to build up a pressure in the portion ci the conduit ahead. of the restrictions before a pressure is built up in the part oi' the conduit in rear oi the restriction, so that an outward iiow through perforations or openings ahead of the restriction takes place before a flow through periorations or openings in rear of the restriction can Itake place. In this manner. the dow of gases through the mutller is also equalized, and since sound waves follow the flow oi' gases, interference of sound waves also results for this reason.

We claim as our invention:

1. A muiiler including an outer shell, heads closingthe ends of said shell, one oi said heads having an opening for receiving gases and sound waves, and the other head having a discharge opening, an intermediate shell connecting said heads and spaced from said outer shell, and an inner shell concentrically arranged within said intermediate shell and having one end arranged to receive gases and having the other end closed and being provided with apertures through which V gases may flow into the space between said inner and intermediate shells, a transverse partition arranged intermediate the ends of said intermediate shell and separating one part thereof from another and also extending across said inner shell in rear of said apertures therein and forming the closure for said closed end of said inner shell, said intermediate shell having two sets of apertures, one located in advance of said partition and the other located in rear of said partition, means forming a concentric passage about said intermediate shell and connecting said apertures of said intermediate snell for conducting gases exteriorly of said intermediate shell from one set of apertures to the other, saidvouter shell and said intermediate shell forming between them a resonator chamber communicating with the interior of said intermediate shell for receiving pressure pulsations therefrom without forming a Dart of the iiow passage of gases through said muffler.

2. A muiiler including a perforate inner shell forming a passage for receiving gases at one end thereof and having the other end thereof closed, a pair of intermediate shells arranged about said inner shell and spaced therefrom and from each other to form passages for gases between said shells, the inner of said intermediate shells re-` ceiving gases from perforations in said inner shell and forming with said inner shell a longitudinal passage for gases and having an apertured zone spaced in a longitudinal direction from the perforations of said inner shell and through which gases now from said passage between said inner shell and the inner oi said intermediate shells into the space between said intermediate shells and having other apertures through which gases are discharged from said space, and an outer shell arranged about said intermediate shells and forming therewith a resonator chamber communicating with the passage between said intermediate shells and arranged exterior to the path of gases dowing through the muiiler.

3. A muiller including an outer shell, heads closing the ends ofosaid shell, one of said heads having an opening for receiving gases and sound waves, and the other head having a. discharge opening, an intermediate shell connecting said heads and spaced from said outer shell, and an inner shell arranged within said intermediate shell and having one end arranged to receive gases and having the other end closed and being provided with apertures through which gases may flow into the space between said inner and intermediate shells, a transverse baille dividing the space between said outer and intermediate shells into a resonator chamber and iiow pamage, said intermediate shell having apertures through which gases may enter and leave said resonator chamber and other apertures through which gases may pass from the space between said inner and intermediate shells into said ow passage, and a transverse baille extending across said intermediate shell and arranged rearwardly of said apertures in said intermediate shell, said intermediate shell also having apertures rearwardly of said baille through which gases flow from said iiow passage to the interior of said intermediate shell for discharge from said muiller.

4. A mufiler including an outer shell, heads closing the ends of said shell, one of said heads having an opening for receiving gases and sound waves, and the other head having a discharge opening, an intermediate shell connecting said heads and spaced from said outer shell and forming therewith a resonator chamber, said intermediate shell having apertures adjacent to said gas receiving head and communicating withsaid resonator chamber, an inner shell arranged within said intermediate shell with its leading end open and disposed in rear of said apertures and arranged to receive gases from said intermediate shell and having the other end'closed and havlng two sets of apertures through which gases may flow out of said inner shell after their pas- Sage into said inner shell from said intermediate shell, a restriction in said inner shell arranged with one set oi' said apertures arranged ahead oi said restriction and with other set of apertures arranged in rear oi said restriction, and means in said muiiier for conducting out oi' the muliler gases discharged from said inner shell.

5. A muiiler including an outer shell, a head closing an end of said shell and having an opening into which a gas conducting pipe may extend, a second shell arranged Within said outer shell, and a support for said securing second shell to the muliler adjacent to said head and having an aperture therein spaced from said head and into which the inner end of said gas conducting pipe fits snugly to provide two spaced supports for said pipe.

6. A muiller including an outer shell, a head closing an end of said shell and having an opening into which a gas conducting pipe may extend, a second shell arranged Within said outer shell, and a supporting member for said second shell, which is supported on said mumer from said head and which extends into the interior of said mui'iler into spaced relation to said head, said supporting member including an annular shoulder engaging said shell and an opening of substantially the same diameter as the opening in said head and in alinement therewith and into which the inner end of said pipe may extend to produce a rigid connection between said pipe and said muiiler.

7. A mufilerincludng a series of shells arranged one within another and forming between them spaces for the passage of gases and sound waves, the inner of said shells being arranged to receive gases at one end thereof and having the other end thereof closed and having a restricted perforate zone to permit gases to discharge into the space between said inner shell and the next shell, said next shell having a set of apertures spaced lengthwise from the perforations of said inner shell and disposed in advance o! the closed end of said inner shell, through which gases pass after passing lengthwise of the space between said inner and said next shell, said next shell also n having another set of apertures in rear of the closed end of said inner shell through which gases pass into the interior of said next shell for discharge from said muiiler, a transverse partltion arranged in said next shell between said sets of apertures, and a side branch resonator chamber formed by some of said shells and connected with a'gas passage of said muiller.

8. A muiller includingan outer shell, headsL heads and spaced from said outer shell and forming therewith a resonator chamber, said intermediate shell having apertures adjacent to said gas receiving head and communicating with said resonator chamber, an inner gas receiving shell arranged within said intermediate shell with its inlet end disposed in rear of said apertures and arranged to receive gases from said intermediate shell and having the other end closed and having apertures through which gases may flow out of said inner shell, and means in said mullier for conducting out of the muiiler gases discharged from said inner shell.

GAIL C. STARKWEATHER. LUCIEN L. HAAS.

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