US 1988048 A
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Patented Jan. 15, 1935 UNITED STATES Momma Paul Peik, Chicago, IlL, assignor to The Halsey W. Taylor Company, Warren, Ohio, at corporation of Ohio Application July so, 1932, Serial No. 628,281
My invention relates to muiilers for silencing the exhaust noise of internal combustion en,- gines and other engines periodically discharging expanding and noise producing pulsating gases.
The general object 01 my invention is to provide, a short compact muiiler having a very high degree of silencing or muilling efficiency combined with a relatively low back pressure.
A further object of my invention is to provide a short compact muiiler capable of efllci'ent scavenging action with reversed flow of the exhaust gases.
A still further object of my invention is to provide a short compact muflier with reversed flow of the exhaust gases in which the exhaust gas streams may readily expand and in which oppositely travelling pulsating exhaust gas streams may partly merge and thus level their shown in Figure 1, the section being taken on line 2-2 of Figure 1;
Figure 3 is a perspective view of the pipe supporting skeleton including the solid separating wall between the inlet and outlet pipes of the muiiler;
. Figure 9; and
Figure 11 1s a perspective view of the pipe supporting skeleton of the muiller shown in Figures 9 and having a partly perforated separating walLbetween the pipes of the muilier arranged in the compartment formed by said separating wall.
In the form ofmuifier for internal combustion engines shown in Figures 1 through 3 of the drawings, an outer preferably cylindrical sheet metal shell 1 is closed at its opposite ends by annular end walls 2, also of sheet metal. Inner partition walls 3, slightly spaced from end walls 2 form narrow spaces 4 at the ends of the cylinder which spaces are filled with foraminous sound absorbing material 5, such as expanded mica, slag wool, steel wool and the like. These packed sound absorbing spaces are not absolutely necessary to the proper functioning of the muflier, and therefore may in most'instances be eliminated.
Mounted within the shell 1 are a series of parallel perforated tubes 6, 7 and 8 through which exhaust gas passes in the order named. Apertured annular sheet metal disks 9 snugly fitted within and adjacent each end of cylinder or shell 1 serve as supports for tubes 6, 7 and 8 and also form chambers 10 and 11, between said disks and partition walls 3 for communication of tubes 6 and 7 and tubes 7 and 8 respectively to induce reversal of the flow of exhaust gas when passing from one tube into the other. The tube 6, the intake tube, extends with its intake end through end wall 2' at the intake end of shell 1 for connection with the engine exhaust, not shown, and at its other end into chamber 10 communicating with pipe 7; The tube 8 communicates at its inner end with chamber 11 and exhausts through end wall 2 at the exhaust end of shell. The tube 7 is solely supported by the apertured disks 9 and communicates at opposite ends with the respective chambers 10 and 11. 'Disks 9 are preferably made from imperforate metal except where provided with aperturesfor tubes 6, '7 and 8. A longitudinally extending separating wall 12 arranged between the inner wall of shell 1 and tube 7, divides the latter into two longitudinal compartment! 14 and 15, each of which accommodates one of the tubes 6 and 8. These compartments are packed with sound absorbing material such as used in the spaces 4, which material occupies the space around the perforated tubes and completely fills each compartment.: The separating wall 12 is welded or otherwise secured at its ends to the disks 9 and at its longitudinal edges to the inner face'or wall of the shell 1 and to the outer face or wall of perforated tube '7. Preferably the separating wall 12 is of solid sheet metal for reasons which will be presently explained. That por-- tion of the tube 6 which passes through chamber. 11 at the inlet end of shell 1, as W as that part of tube 8 which passes through chamber 10 at the exhaust end .of the shell 1 are solid, that is the perforations formed in the remainder of these tubes are omitted.
Exhaust gases" entering tube 6 flow therethrough into chamber 10 thence back through tube '7 into chamber 11 and finally into and through tube 8 to the open atmosphere. This lQW takes place because the solid wall 12 separates the tubes 6 and 8, in which the flow of gas is in the same direction. The tube '7 in which the flow of gas is in opposite direction communicates with tubes 6 and 8 through the perforations of all tubes and the sound absorbing material occupying the space around the perforated tubes.
It is understood that compartments 14 and communicate with each other through perforated tube 7 and that the perforated tubes 6 and 8 arranged in said compartments communicate indirectly with each other. This is a most important feature of my invention. If the employment of solid wall 12 would not permit such communication, it would 'be necessary to make the diameter of the cylinder or shell 1 much larger in order to make compartments 14 and 15 large enough for the efficient absorption of sound in the sound absorbing material packed therein. However, by virtue of the perforated tube 7, which serves as an elongation of the separating wall 12 separating the inner chamber of shell 1 into compartments 14 and 15, .the impulses in the gas stream passing through tubes 6, '7 and 8 are not confined to the compartment housing each particular tube, but are free to expand through the perforated tube 7 directly into the other housing and its perforated tube in which the flow of gas is in the same direction. Thus impulses in the stream of exhaust gases flowing through tubes 6 and 8 in the same direction, that is from the front to the rear of the muflier, are not free to merge directly with each other, but only indirectly through tube 7, whereas the impulses in the stream of gases flowing through tube '7 in a direction opposite to that of the flow through tubes 6 and 8 are free to merge with the latter and viceversa. This makes it possible for the high impulses in the gas streams in tubes 6 and 8 to expand through the perforations of their tubes and: ierge with the low impulses of the gas stream in perforated tube '7, and this merging of the high and low impulses is continuously taking place throughout the entire muiiler. As the gas streamsin tubes 7 and tubes 6, 8 are flowing in opposite directions the merging action is greatly multiplied and consequently an extremely high degree of mufliing efficiency is attained in spite of the fact that the muiiler is of very short length. As the direction of flow of gases passing through tubes 6 and8 is the same in each of said tubes, and the shearing or merging action previously referred to can not take place under .such conditions, separating 1 wall 12 is made solid to separate these tubes from each other. If wall 12 should be perforated, then the merging eificiency between tubes 6 and 8 would be no greater than that of a conventional straight stream acoustic muffler, because the mufliing effect attained the short muflier would be insuiiicient to prevent noise with many engines'now on the market, particufrom one tube' through the sound absorbing material into the low pressure area of the ex-' seeping passagesbetween their individual gas channels show a very material increase in back pressure, as compared to that of straight stream mufflers of the same capacity. This is due to the fact that the entire stream is twice completely reversed in the former structure. In my present invention 1 provide for a progressive transfer of exhaust gases from one compartment to the other compartment, which transfer takes place through a tube in which the, exhaust gas stream travels in opposite direction ascompared with the direction of travel of gas in the tube from which the peaks of the gas stream are expanded. Thistransfer action more than compensates for the increase in back pressure set up by the two reverses of the gas stream.-
The progressive transfer or merging of im-'-' pulses also results in a'highly efficient scavenging action, as the gases are not trapped in the -muifler, but are constantly passing along the inner shell from one chamber to the other so that the entire mufiler becomes hot and is maintained at a temperature above the condensation of water and other liquids present in the exhaust gas, even in extremely cold weather and under conditions of intermittent and slow impulses through the elongated passage 16 between the inner wall of shell 1 and tube 7'. A material increase in the size of this passage .by spacing tube 7' a greater distance from the inner wall of shell 1 would decrease the silencing action of the muflier because a substantial volume of insuiiiciently merged and muflied gas will enter into tube 8 and thence be exhausted with substantial noise. Space 16 should be held to a size which insures suflicient merging between expanded gas peaks from tube 7 with the V gas creeping and passing through said space 16.
in Figures 6, 7, and 8 which is generally the same as the preferred form of the invention shown in Figures 1 through 3 the perforations of tube 7" extend only half circumferentially H around the said tube 7" and at opposite ends of said tube are approximately 180 offset with respect to each other. Consequently one half of the'length of the tube is perforated for communication with chamber 14.and the other half of the tube is perforated for communication with chamber15, see Figures 7 and 8. This arrangement decreases the merging action of the exhaust streams in tubes '7" and 6 but prevents direct expansion of peaks of the exhaust gas stream from tubes 6 into tube 8. Such inufiler possesses high mufliing efficiency for extremely In the modified form .of the invention shown short structures but shows a slight increase in back pressure as compared with the very low back pressure of the previously described structures.
The modified form of the invention shown in Figures 9 and 11 shows a mufller with a non-perforated intake tube 18 displacing tubes 7 and 7" of the structures shown in the previous figures. The tubes 19 and of the modified form are perforated and arranged in compartments 14' and 15' separated from each other by a separat ing wall 12' similar to the arrangement of wall 12 previously described, with the exception that wall 12' is perforated throughout approximately half its length. The direction of the exhaust gas in tubes 19 and 20 being opposite, the partly perforated separating wall 12 is provided to permit expansion of the peaks of the exhaust gas stream and merging of these streams with satisfactory muflling action, but the back pressure of this structure is slightly increased as compared with the very low back pressure of the structures shown in Figures 1 through 5.
Having thus described my invention, what I claim is:
1. In a reverse stream mufller for silencing the exhaust poise of internal combustion engines, a shell provided with intake and outlet openings and longitudinally subdivided into parallel compartments, foraminous sound absorbing material in said compartments, a gas passage in each of said compartments, one of said gas passages being in communication with saidintake opening and another in communication with said outlet opening, and a gas passage arranged parallel to, intermediate of and partly within each of said compartments and in direct communication with said other gas passages to provide a single continuous passage through the muffler andthe walls of said passages being foraminous to permit seepage of exhaust gas from these passages into said compartments and back into said passages.
2. In a reverse stream mufller for silencing the exhaust noise of internal combustion engines, a shell longitudinally subdivided into two parallel compartments, foraminous sound absorbing material in said compartments, a perforated tube in each of said compartments, a tubular extension for one end of each of said perforated tubes, said tubular extensions being extended through the opposite end walls of said shell to provide intake and outlet passages for said muffler, and a third perforated tube arranged parallel to, intermediate of and partly within each of said compartments for indirect communication with said compartments and their respective perforated tubes, said third perforated tube directly communicating at opposite ends with said two perforated tubes to provide a continuous unrestricted and reversed gas passage through said shell.
3. In a reverse stream muiller for silencing the exhaust noise of internal combustion engines, a shell provided with intake and outletpassages and longitudinally subdivided into two parallel compartments, longitudinally communieating through a narrow space with each other, foraminous material within said compartments, a perforated tube longitudinally extending in each of said compartments, one of said perforated tubes communicating with said intake passage and the other onewith said outlet passage, and a third preforated tube arranged parallel to and intermediate said two compartments for communication with each of said compartments and their respective gas passages, said third perforated tube being in direct communication with said other perforated tubes to provide a single reversed and unrestricted passage through said muflier.
4. In a reverse stream muffler for silencing the exhaust noise of internal combustion engines, a shell provided with intake and outlet passages and longitudinally subdivided into parallel compartments by a solid wall, a perforated tube supported upon the upper edge of said wall and contacting with the inner wall of said shell, to permit communication of said compartments with each other through said tube, a perforated tube longitudinally arranged in each of said compartments and sound absorbing and deadening material packed within said compartments and enclosing said tubes, one of said last mentioned tubes being'in direct communication with the intakepassage and the other of said lastmentioned tubes being in direct communication with said outlet passage, said tubes being in direct communication with said first-mentioned perforated tube to provide an unobstructed reversed single gas passage through said shell and permitting expansion of the peaks of explosion impulses into said compartments and the tubes therein.
5. In a reverse stream muflier for silencing the exhaust noise of internal combustion engines, a shell provided with intake and outlet openings and longitudinally subdivided into two parallel compartments, foraminous sound ab sorbing material in said compartments, a gas passage in each of said compartments, one of said gas passages being in communication with said intake opening and the other one in com munication with said outlet opening and a gas passage arranged parallel to, intermediate of and partly within each of said two compartments, the walls of said passages being foraminous for affording communication between each of said compartmentsand its gas passage, said latter gas passage being in directcommunication with said other two gas passages to provide a single continuous and reversed gas passage through the muiiler and the foraminous walls of said passages permitting seeping of exhaust gas from these passages into said compartments. 6. In a reverse stream mufller for silencing the exhaust noise of internal combustion engines, a shell provided with intake and outlet passages and longitudinally subdivided into parallel compartments by a partly perforated wall, a tube supported upon the upper edge of said wall and contacting with the inner wall of said shell, a perforated tube longitudinally arranged in each of said compartments and sound deadening material packed within said compartments and enclosing said perforated tubes therein, said tube supported in said wall being in direct communication with said inlet passage a'nd one of said perforated tubes, the other one of said perforated tubes being in direct communication with said last perforated tube and said outlet passage to provide a single gas passage through said mufiler having the exhaust gas stream flowing through said perforated tubes in opposite directions and permitting expansion of the peaks of explosion impulses from one of said perforated tubes into its compartment and thence through said perforated wall into the other compartment and its perforated tube.
PAUL G. PEIK.