|Publication number||US2059487 A|
|Publication date||Nov 3, 1936|
|Filing date||Oct 31, 1932|
|Priority date||Oct 31, 1932|
|Publication number||US 2059487 A, US 2059487A, US-A-2059487, US2059487 A, US2059487A|
|Inventors||Peik Paul G|
|Original Assignee||Halsey W Taylor Company|
|Export Citation||BiBTeX, EndNote, RefMan|
|Referenced by (17), Classifications (13)|
|External Links: USPTO, USPTO Assignment, Espacenet|
P. G. PEIK Nov. 3, 1936.
MUFFLER Filed Oct. 31, 1932 L7 La G- PUK Mmm, 7L mw@ www:
Patented Nov. 3, 1936 PATENT OFFICE MUFFLER raul G. Peik, chicago, nl., W. Taylor Company, W tion of Ohio assignor to The Halsey arren, Ohio, a corpora- Application October 31, 1932, Serial No. 640,558
This invention relates to muillers for silencing the exhaust noises of engines, particularly of .internal combustion engines. y
The generalobject of the invention is to provide a combined acoustic and resonator mulller, of exceptionally low production cost having adegree of compactness heretofore unattained in muillers of comparable eiliciency.
Another object of the invention is to provide a durable eillcient combined 'acoustic and resonator muiller of low construction cost which embodies a series of resonator chambers of substantial length When compared with the length of the muffler.
Still anotherv object of the invention is to provide a combined acoustic and resonator muffler of the type referred to above with a series of resonator chambers tuned within narrow ranges with respect to each other to broaden the range of frequencies in which the muffler will silence low sound frequencies f Fundamentally all Asound deadening is due to resonance action. The highest eiiici'ency of sound deadening,that is, elimination of any sound wave in one cycle,-is attained only by providing a separate chamber tuned exactly to the length of that wave. This method yis not feasible in a muiiier, due to the multiplicity of sound waves in the exhaust stream, and the constant variation of their frequency due to the acceleration and de-celeration of the engine. While each individual air space in sound absorbing material employed in muilers of the so-called acoustic type, is far too small to have an eillcient sound deadeningl action in one cycle, acoustic mufllers are nevertheless very efficient in deadening high frequencies of sound due to the multiplicity of air spaces and the high rate of oscillation ofthe high frequencies. Thus, the so-called acoustic mufliers are extremely eilicient in eliminating the high frequencies, but (for reasons which are explalned later) are so inefiicient in their action on the low frequencies that such muiliers must be' made in a considerable length to obtain the necessary elimination of the low sound frequencies, so long in fact that it is common practiceto make them in two units so that they can be mounted between the re-inforcing members of the modern automobile chassis.
'I'he following brief reference to a'coustic muffiers and resonator muiiiers will serve to show how the above objects are attained and to bring out the main/features of the invention.
Resonator muiliers in 'turn are extremely efiicient in deadening low frequencies in an exhaust gas stream. Their efficiency is limited due to the multiplicity of sound waves in the exhaust stream 4use is limited to automobiles with relatively large frame structures.
The objects and advantages of the invention,
will become more apparent fromthe following description, when taken in conjunction with the accompanying drawing, wherein:
Figure l is a longitudinal sectional view of an exhaust mufer according to the invention, the section being taken on line I--l 'of Figure 2;
. Figure 2 is a transverse sectional View taken on line 2--2 of Figure 1;
' Figures 3 and 4 are ytransverse sectional views taken on lines 3-3 and 4-4 respectively of Figure 1; I
Figures 5 through 3 show a slightly modified form of the muliier provided with separating fins to increase the number of resonator chambers employed, thus, Figure 5 is a longitudinal sectional view through the modified muffler taken on line 5 5 of Figure 6;
Figure 6 is a transverse sectional view taken on line 6-6 of Figure 5;
Figures 7 and 8 are transverse sectional views taken on lines 1--1 and 8 8 respectively of Figure 5.
Referring more particularly to the structure disclosed in Figures l through 4 of the drawing,
- the muffler I comprises a series of telescoped cylinders 2, 3 and 4 arranged in spaced relationship with respect to each other. The outer cylinder 2 and the adjoining cylinder 3l are connected at opposite ends in any suitable manner, as by welding to the front and rear end Walls 5 and 6 respectively, thus forming resonator chamber 'l of ring shaped cross-section between these two cylinders. End wall 5 is formed with an inlet extension 8 having an outlet opening 9, and end wall 5 is centrally perforated to form an opening I0.
'Ihe third cylinder 4 lis somewhat shorter and at its rear end welded to rear end wall 6. The front end of cylinder 4 is welded to an inner wall I2 which in turn is secured to the inner wall of cylinder 3. Front end wall 5 is spaced a slight distance from inner wall I2 due to the difference in length between .cylinders 3 and 4, thus forming a chamber Il at the front end of the muiller.
Cylinder 4 encloses a round sleeve or pipe IB in axial alignment with the respective inlet and outlet openings 9 and I0, and extending from inlet opening I3 in inner wall I2 of shell 4 to and through opening I in rear end wall 8, thus forming a ring shaped chamber il within cylinder 4. Pipe I5, which is made of perforated sheet metal, communicates through its periorations with the interior of cylinder 4 surrounding said pipe. The ring shaped chamber Il in cylinder 4 is packed with any sound absorbing fire proof material i8 such as expanded mlcaceous material, slag wool, steel wool etc. and communicates with the space inside of pipe I5, as previously described, which space constitutes an unobstructed main passage for the exhaust gas.
'I'he silencing efficiency of the structure Just described is more eiective on the high sound Irequencies than on the lower ones, the latter being more readily muilied or silenced by resonating action. Good muiiling on both high and low frequencies has heretofore only been obtained by employing relatively long mufiiers, which as pointed out above cannot be used on reinforced short frame structures of automobiles. In order to obtain a resonator effect in combination with the acoustic action of the muiiier so far described without greatly increasing the length of the muier, the space between shells 2, 3 and 4 is utilized as a resonator chamber I9. Chamber I9 which may be tuned to silence the loudest period of the low sound frequencies of the exhaust gas stream, is approximately twice the length of the outer cylinder 2 and consequently is about double the length o! the muiiler as a whole, one half of the length of chamber I9 constituting the outer ring shaped space between cylinders 2 and 3, and the other half constituting the inner ring-shaped space between cylinders 3 and 4 which in effect serves as a second resonator chamber.
A series of openings or slots 20 in the wall. of cylinder 3 close to one end thereof provide direct communication between the two halves of chamber I9, and a series o! openings 2| in the wall of said cylinder close to the opposite end thereof provide direct communication between chamber I4 and one end only of resonator chamber I9. Therefore as the chambers are connected in series the same will be caused to function as a compound resonator.
For internal combustion engines having an unusually complex combination of distinct loud periods o1 low frequencies the number of resonator chambers of the mufiier is preferably increased. Such a structure is disclosed in Figures 5 to 8 of the drawing, wherein I show a mumer closely resembling the structure shown in Figures i-4, with the exception that the space between shells 2 and l and shells 3 and 4 is subdivided by fins 22 and 23 respectively, whereby two elongated reversed or U-shaped resonator chambers 24 and 25 o! substantial length are formed, which therefore function as a simple resonator. The length of chambers 24 and 25 may be individually adapted to silence the loudest periods of the two lowest sound frequencies of the exhaust gas stream by arranging the communicating openings or slots 2D', 20" in cylinders 3 and 4 more or less apart from the end of said cylinders, but slots 2li should be so positioned that the chambers `24 and 25 will be substantially longer than the length of the outer cylinder 2 and consequently longer than the length of the muiiier as a whole. The communicating passages 2| between the halves of chambers 24 and 25 are arranged similarly to openings 2l in the muffler previously described.
It will be understood that muiiiers according to the invention can readily be built with any number of simple resonator chambers of the required tuning either by providing further subdivisions by means of additional fins, or by increasing the number of shells or cylinders, and that these muiiiers possess very high mufiiing efficiency despite the fact that the length of the muilier is comparatively short.
Having thus described my invention, what I claim is:
A muiiier for silencing the exhaust noise of internal combustion engines, comprising an unobstructed main passage having a plurality o! per- Icrations therein, an expansion chamber having sound absorbing material packed therein and encircling said passage and communicating therewith through said perforations, and two substantially U-shaped resonator chambers, each being of substantially lgreater' length than said muiiier and each being in communication with the main passage, said resonator chambers being spaced from the main passage by ditlerent radial distances.l
PAUL G. PEIK.
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|International Classification||F01N1/02, F01N1/00, F01N1/24|
|Cooperative Classification||F01N1/02, F01N1/24, F01N2490/15, F01N1/023, F01N1/006|
|European Classification||F01N1/02B, F01N1/00B1, F01N1/24, F01N1/02|