US2690812A - Muffler construction - Google Patents

Description

Oct. 5, 1954 R. K. SPARROW MUFFLER CONSTRUCTION Filed May 9, 1950 INVENTOR. .HAYMUND K 51 11122217142 Patented Oct. 5, 1954 MUFFLER CONSTRUCTION Raymond K. Sparrow, Toledo, Ohio, assignor to Goerlichs, a partnership, Toledo, Ohio Application May 9, 1950, Serial No. 160,960

7 Claims. 1

This invention relates to acoustic attenuating devices and more especially to an acoustic attenuating construction particularly usable with the exhaust system of an internal combustion engine.

The invention comprehends the provision of an acoustic attenuating device particularly adaptable for controlling the audibility of sound waves sent up by the moving gases in an exhaust system of an internal combustion engine.

The invention has for an object the provision of a mufiler construction for an exhaust gas system wherein a plurality of chambers are incorporated providing means for attenuating sound yet facilitating the flow of exhaust gases therethrough without setting up appreciable resistance to gas flow.

Another object of the invention resides in the provision of an acoustic attenuating device for use with a sound entrained gas stream which is formed with a plurality of sound attenuating chambers and passages, and walls of the passages being configurated with acoustic couplings or openings for facilitating the attenuation of sound waves.

Another object of the invention is the provision of a method of controlling the attenuation of sound waves of a moving gas stream, the gas inlet of the device being correlated with respect to gas passages and sound attenuating means contained within the device providing for predetermined control of acoustic attenuation whereby certain groups of sound waves are unattenuated to produce audible tones.

A further object of the invention is the provision of a sound attenuating mufiier construction for use with the exhaust stream of an internal combustion engine embodying sound attenuating chambers or sound wave traps and gas passages acoustically coupled therewith, the gas inlet passage being angularly disposed with respect to the general direction of movement of the gases through the muffler whereby the effectiveness or extent of sound attenuation of the construction may be modified by varying the radial angle of incidence of the gas inlet with respect to the gas passages and sound attenuating means.

Still a further object of the invention is the provision of a muiiler construction for use with a moving stream of exhaust gases, the mufiier being generally cylindrical in configuration and embodying a multilayer shell to enhance the rigidity of the shell so as to reduce reverberations and secure desirable audible tonal qualities from the construction.

Still another object of the invention is the provision of a muffier construction embodying gas passages and sound attenuating means associated with a gas inlet passage, the particular positioning of the latter with respect to the sound attenuating means and gas passages predetermining the unattenuated waves resulting in certain tones emanating from the mufiler whereby the construction may be tuned to a particular range of sound vibrations or tones.

Further objects and advantages are within the scope of this invention such as relate to the arrangement, operation and function of the related elements of the structure, to various details of construction and to combinations of parts, elements per se, and to economics of manufacture and numerous other features as will be apparent from a consideration of the specification and drawing of a form of the invention, which may be preferred, in which:

Figure 1 is an isometric view illustrating an embodiment of my invention, a portion of the shell being broken away to admit an illustration of the interior construction;

Figure 2 is a longitudinal sectional view of the mufller construction illustrated in Figure 1;

Figure 3 is a transverse sectional view taken substantially on the line 33 of Figure 2;

Figure 4 is an end view of the mufller construction illustrating the gas inlet passage or tube disposed at a six oclock position with respect to the interior components of the muflier construction;

Figure 5 is a view similar to Figure 4 illustrating an angle of incidence of the gas inlet tube disposed radially in an eight oclock position;

Figure 6 is a view similar to Figure 4 illustrating the gas inlet tube disposed in a radial angle equivalent to a ten oclock position, and

Figure 7 is a similar view illustrating the gas inlet tube arranged at a twelve oclock position.

While I have illustrated a form of my invention as particularly adaptable for use with a moving stream of exhaust gas from an internal combustion engine, it is to be understood that the principles of my invention may be utilized in other types of sound attenuating devices.

Referring to the drawings in detail the acoustic attenuating device or muflier is inclusive of a substantially cylindrical shell it) which is preferably formed of double wall configuration fashioned by rolling up a length of sheet steel or other suitable material to the configuration illustrated in Figure 3 forming wall laminations I2 and M. The ends of the sheet of material are preferably overlapped and spot welded as indicated at [5 to the wall laminations l2 and [4. This arrangement provides a strong shell which may be fabricated of relatively thin gauge metal which may be readily processed or Worked into cylindrical configuration with greater facility than a thicker metal. Such a multiple thickness wall minimizes metallic sounds and provides a degree of rigidity minimizing vibration of the shell wall structure and enhancing the attenuating characteristics of the mufiler. Disposed in the respective ends of 3 the muiiier shell II] are end heads I! and 18. The head I! at the inlet end of the mufller is provided with a gas inlet tube or passage 20 while the head I 8 at the rear of the mufller is provided with a gas outlet or exhaust tube 2|.

Disposed interiorly of the mufiler shell are circular bafile plates or transversely disposed walls 23, 24 and 25 which subdivide the interior into compartments or chambers 21, 28, 29 and 3D. The plates 23, 24 and 25 are provided with aligned openings in which is disposed a tube or pipe 32 providing a direct or through passage for conducting exhaust gases from chamber 21 to the chamber 30. The periphery of the tube 32 is formed with a number of relatively small openings 34 for establishing acoustic communication or couplings with the chambers 28 and 29. The heads 23 and 24 are provided with openings to accommodate a tube or passage 35 which provides a supplemental gas passage and acoustic coupling between the chamber 2'! and the sound attenuating chamber 29. The tube 35 is likewise provided with a plurality of relatively small openings 31 which form acoustic coupling means with the acoustic or sound attenuating chamber 23.

The exhaust gases passing through the muffler may travel the direct path provided by the tube 32 or by way of the tube 35, acoustic coupling openings 34 and 3'! and the chambers 28 and 29. Thus the gases are provided with a direct passage and bypass paths, the openings 34 and 3'! in conjunction with the chambers in the muffier forming effective attenuating means for eliminating or substantially reducing or damping certain sound waves entrained with the gas stream.

The particular interior construction of the muffier of my invention is of a character which attenuates sound vibrations of relatively high pitch while permitting the passage of sound waves which produce tones of a lower vibratory range. One of the advantages of my mufiler construction is the facility with which it may be readily adapted by slight reorientation of the gas inlet passage to modify or alter the range or efffectiveness of acoustic attenuation of sound waves passing through the mufiler. This provides a medium for controlling the audible sound waves permitted passage through the mufiier. I have found that by shifting or changing the radial orientation of the gas inlet tube with respect to the position of the tubes 32 and 35 in the muiiler the efiectiveness of attenuation or range of sound waves attenuated may be varied within predetermined limits and thus modify the audible sounds emanating from the muffler. Thus with the gas inlet tube 28 in the relative position illustrated in figure 4, a predetermined tonal range of audibility is obtainable. With the gas inlet tube 20 moved radially to 8, and 12 oclock positions respectively illustrated in Figures 5, 6 and 7, the audible tonal range may be varied. In this manner a muiiier may, in a measure, be tuned in the exhaust stream emanating from a particular engine to attain a predetermined pitch of audibility as desired by the user. I attribute the advantageous results of varying the range of audibility of tones emanating from a mufiier to the particular angle of incidence of the gas stream with respect to the relative position of the tubes 32 and 35 in the muilier. Modifying the angle of the incoming gas stream causes the gases to move through the muiiier in modified directions and afiects the path of entrained sound waves so that certain vibrations may be attenuated with one setting or adjustment of the gas inlet tube, which with another modified or changed position of the inlet tube would be unattenuated. I have found that while the acoustic attenuating characteristics of one setting of the gas inlet results in a definite range of audibility when the muffler is used with a particular engine, a different range of audibility may result when the device is used with another engine. By changing the radial position of the gas inlet tube relative to the interior components of the muffler, the audible tonal qualities resulting from unattenuated waves passing through the muffler may be varied or modified to fit individual installations.

It should be noted that the axis of the gas inlet passage 2t is disposed so that irrespective of the relative radial angular position of the tube, the gas stream enters at the central or longitudinal axis of the mufiier.

It is apparent that, within the scope of the invention, modifications and different arrange ments may be made other than is herein disclosed, and the present disclosure is illustrative merely, the invention comprehending all variations thereof.

I claim:

1. A mufiler for use with a moving gas stream including a longitudinal shell; a plurality of transversely disposed baffle walls arranged in spaced relation in said shell forming aplurality of chambers therein; a tube extending through said baflle walls providing a generally through path for the passage of gases; a second tube of lesser length than said first mentioned tube disposed in said shell; said tubes being disposed in laterally spaced relation with respect to the axis of the shell; said second mentioned tube open-- ing into but not extending through one of the intermediate chambers formed by the baflle walls;

a plurality of relatively small openings formed in the walls of said tubes providing bypass means for the gases and acoustic couplings between the tubes and the chambers adjacent thereto; a gas inlet tube connected to one end of the shell and disposed at an acute angle with respect to the longitudinal axis of the shell; the

radial position of said inlet tube relative to the gas passage tubes in the shell determining a range of attenuation of sound waves entrained in the gas stream.

2. A sound attenuating means for use with a moving gas stream including, in combination, anelongated shell, a pair of gas passage tubes of different lengths extending lengthwise within the shell and being disposed in laterally spaced rela-' tion with respect to the axis of the shell, a plu rality of transversely arranged baiiles spacedlongitudinally in said shell and forming a plu-. rality of chambers therein, said tubes having a. plurality of relatively small openings formed in the walls thereof providing bypass means for the gases and acoustic couplings with the chambers adjacent the tubes formed by said baflies, gas inlet and outlet tubes connected respectively to the ends of the shell, said gas inlet tube being dis' posed at an acute angle with respect to the longi-' tudinal axis of the shell, the radial position of said inlet tube relative to the gas passage tubes in the shell determining a range of attenuation of sound waves entrained in the gas stream.

3. A sound attenuating means for use with a moving gas stream including, in combination, an

elongated shell, end heads secured to the shell, a:

plurality of spaced transverse walls in said shell forming end chambers and intermediate chambers in the shell, a gas passage tube extending through the transverse walls and opening into but not extending through the end chambers, the axis of said tube being spaced laterally from the axis of the shell, a plurality of relatively small openings formed in the tube walls providing acoustic coupling means with one of the intermediate chambers, gas inlet and outlet pipes connected respectively to the end heads of said shell, the entrance of the inlet pipe being on the longitudinal axis of the shell, said inlet pipe being disposed at an acute angle with respect to the longitudinal axis of the shell, the radial position of said inlet tube relative to the gas passage tube in the shell determining a range of attenuation of sound waves entrained in the gas stream.

4. A mufller for use with a stream of gases including, in combination, an elongated shell having a double wall formed of a single sheet of metal, the end zones of said sheet bein in overlapping relation and secured to an intermediate zone of the sheet, end heads secured to the shell, a plurality of transversely arranged bafiles in said shell forming a plurality of chambers therein, a pair of tubes disposed in said shell in laterally spaced relation with respect to the longitudinal axis 0 the shell, one of said tubes extending through said baiiles and having its ends opening into but not extending through chambers formed in the end portions of the shell by certain of the baffles, a plurality of relatively small openings formed in the walls of said tubes providing bypass means for the gases and acoustic couplings between the tubes and the chambers adjacent thereto, a gas inlet tube connected to one end of the shell and disposed at an acute angle with respect to the longitudinal axis of the shell, the radial position of said inlet tube relative to the gas passage tubes in the shell determining the range of attenuation of sound waves entrained in the gas stream.

5. A mufiier for use with a gas stream including, in combination, an elongated shell having end closures and a double wall formed of a single sheet of metal, the end zones of said metal sheet being in overlapping relation and secured to an intermediate zone of the sheet, a plurality of transversely arranged baffle walls in said shell forming a plurality of chambers therein, a pair of tubes disposed in said shell in laterally spaced relation with respect to the longitudinal axis of the shell, one of said tubes extendin through said bafile walls and having its ends opening into but not extending through chambers formed in the end portions of the shell by certain of the bafiles, the other of said tubes extending through one of said chambers, a plurality of relatively small openings formed in the walls of said tubes providing bypass means for the gases and acoustic couplings between the tubes and the chambers adjacent thereto, a gas inlet tube connected to one end of the shell and disposed at an acute angle with respect to the longitudinal axis of the shell, the radial position of said inlet tube relative to the gas passage tubes in the shell determining the range of attenuation of sound waves entrained in the gas stream.

6. A muffler for use with an exhaust gas stream of an internal combustion engine including an elongated shell; end heads secured to the shell; transverse walls in said shell in spaced relation forming sound attenuating chambers therein; a

gas passage tube extending through openings in said walls, said tube having a plurality of relatively small openings formed in the walls thereof forming acoustic couplings with said chambers; a second tube of lesser length than said first mentioned tube extendin through one of said chambers and having a plurality of openings formed in the walls thereof forming acoustic couplings with the chamber through which the tube extends; said tubes being disposed in laterally spaced relation with respect to the axis of the shell gas inlet and outlet tubes connected respectively to the end heads of the shell; the axes of said gas inlet and outlet tubes being disposed in substantially parallel relation and positioned at acute angles with respect to the longitudinal axis of the shell, the relative radial position of said inlet tube with respect to the gas passage tubes in said shell determining a range of acoustic attenuation of sound waves entrained within the gas stream passing through the muf- Her.

7. A muffler for use with an exhaust gas stream of an internal combustion engine including an elongated shell having a laminated wall; end heads secured to the shell; three transverse walls in said shell in spaced relation forming a pair of intermediate sound attenuatin chambers and end chambers therein; a gas passage tube extending through said intermediate sound attenuatin chambers, said tube having a plurality of relatively small openings formed in the walls thereof forming acoustic couplings with both said chambers; a second tube opening into but not extending through one of said intermediate chambers and having a plurality of openings formed in the Walls thereof forming acoustic couplings with the chamber through which the tube extends; said tubes bein disposed in laterally spaced relation with respect to the axis of the shell; gas inlet and outlet tubes connected respectively to the end heads of the shell; the axes of said gas inlet and outle tubes being disposed in substantially parallel relation and positioned at acute angles with respect to the longitudinal axis of the shell, the relative radial position of said inlet tube with respect to the gas passage tubes in said shell determinin a range of acoustic attenuation of sound waves entrained within the gas stream passing through the muffler.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 781,939 Fulton Feb. 7, 19-05 877,431 Jones Jan. 21, 1908 1,512,859 Powell Oct. 21, 1924 1,542,829 Oldberg June 23, 1925 1,732,909 Noblitt et a1. Oct. 22, 1929 2,144,725 Manning Jan. 24, 1939 2,189,424 Leadbetter Feb. 6, 1940 2,277,132 Moss Mar. 24, 194 2,357,791 Powers Sept. 5, 1944 FOREIGN PATENTS Number Country Date 882,317 France May 31, 1943

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