US2359365A - Muffler - Google Patents

Description

M. KATCHER Oct. 3, 1944.

MUFFLER Filed May 20, 1943 2 Sheets-Sheet 1 NVENTOR. Morn Kalcher ATTORNEY Oct. 3, 1944. M. KAT CHER 2,359,365

MUFFLER Filed May 20, 1945 2 Sheets-Sheet 2 ail- S M I VENTOR. BY arms Iadcher ATTOR N EY Patented Oct. 3, 1944 UNITED STATES PATENT OFFICE 11 Claims.

This invention relates to mufflers or silencers for use in connection with the elimination of the noise caused by the sudden flow of gases, for example, from the exhaust manifold of an internal combustion engine.

It is an object of this invention to produce a mufiler with a resonance device inside the main chamber, which device takes part of the gas entering the muiiler and then sends this part back again to flow through the bafile with the rest of the gas. In some fprms the resonance device has a fixed period as determined by its length, in other forms the length is continuously adjustable and in still another form the length can be varied in definite amounts. The resonance device acts to reduce the effect of the periodicity of the impulses received from the gases emitted as a result of the successive explosions in the engines cylinders.

Another object of the invention is the method of production of the spiral member. This memher is a troublesome and expensive one to make ordinarily but with my method it can be economically produced. It requires nothing more than a plurality of split washers which are joined end to end at the split after first having been bent longitudinally to separate the edges at the split. The method lends itself particularly to the production of a spiral in which the distance between the successive turns is varied as this is simply accomplished by separating the split edges mor and less for the successive washers. In the preferred form the distance between successive turns increases toward the outlet end of the muffler, in which case the split edges of successive washers are successively increased in ofiset.

Other objects and advantages will become apparent upon further study of the description and drawings, in which:

Fig. 1 is a sectional plan of the mufiler with a fixed length resonance chamber, the spiral member being shown in elevation.

Fig. 2 is an elevation of a portion of a spiral member formed of joined split Washers.

Fig. 3 is a section taken along the line 33 of Fig. 2.

Fig. 4 is a section taken along the line 44 of Fig. 1.

Fig. 5 is a sectional plan of a muffler with a continuously adjustable resonance chamber, the spiral being shown only where cut.

Fig. 6 is a partial sectional plan of a mufller with a resonance chamber adjustable to predetermined lengths, the spiral being shown only where cut.

Fig. 7 is a section of Fig. 5 taken along the line 1l, and

Fig. 8 is a partial sectional plan of a mufiler wherein the housing is grooved to receive the outer periphery of the spiral member.

The muffler of Figs. 1 and 4 is provided with a casing or housing 9 formed of two halves crimped together at flanges l0. Extending centrally through housing 9 and end pieces II and I 2 is a resonance tube I3. End pieces H and [2 are spot welded at their inner edges to tube I 4 and at their outer edges to casing 9. Supported between tube I 3 and housing 9 is a spiral member [4. Member I4 is welded in several places at each turn to tube l 3. The pitch of the spiral is reversed at points [5 and I6 and increases toward end piece I2. Increasing the pitch of the spiral allows the gas to expand more rapidly thereby reducing its velocity. In a broad sense it can be said that the spiral has a variable pitch which does not necessarily increase toward the outlet, although this is the preferred form. For example, the increase could be toward the inlet end of the chamber.

Tube [3 is provided with openings ll near the inlet end of chamber l9 and with openings 18 near the outlet end of said chamber. Inside of tube 13 is a diaphragm 20. 1

In operation, gas from the successive explo sions of the engine is forced into tube l3 at the inlet end. Part of the gas leaves the tube through openings l1 and continues through spiral member 14 entering tube 13 again at openings [8 and finally being discharged from the open end of the tube. The other part of the gas received at the inlet end of tube l3 continues along the tube until it strikes diaphragm 20. It is reflected back therefrom and then leaves the tube at openings I! from whence it goes along with the rest of the gas about spiral member [4. The second part of the gas is thus out of phase with the first part of the gas tending to break up any resonance that might develop in the mufller due to the periodicity of the successive quantities of gas received at the successive explosions in the cylinders of the engine. It is well known in the wave theory of propagation that out or phase waves tend to neutralize each other. In making the muflier, the length in the resonance tube I3 between its inlet and diaphragm 20 is determined for the particular engine type with which it is to be used. As will be seen later on, this invention includes types of resonance tubes in which said distance is not fixed as with the form described above, but is adjustable.

In one method of manufacturing the spiral member, a series of split washers are used. In Figs. 3 and 4, for example, each turn 2! of the spiral member is a split washer, the part of a turn extended over by a washer being substantially 360 degrees less the amount of overlap 22. Each washer is bent longitudinally or axially, so that the edges at the split are separated longitudinally or axially. One edge at the split of the previous washer is then set to overlap the opposite edge of the next succeeding washer as shown at 22. The overlapped edges are then welded by spot welding or otherwise fastened together. In this manner, the complete spiral member is formed. To increase the space between turns as the outlet end of the mufller is approached, the split edges of the washers are pulled more widely apart. This is an economical method of producing the spiral, and further the overlapped edges increase the friction of the flow of the gas through the mufller.

The mufiler of Fig. 5 is similar to that of Fig. 1 except that the length of the gas column in the resonance tube 23 can be continuously varied. As before the housing or casing 9 contains a spiral member [4 wrapped around a central cylindrical member to which it is welded, in this case said member being resonance tube 23. The outer edge of spiral member l4 contacts the inside of housing 9. Openings I! are provided in tube 23 near the inlet end of chamber 19 and other openings 68 near the outlet end of said chamber. Tube 23 extends through end piece H at the inlet end and through end piece 12 at the outlet end. Near the outlet end of said tube is fastened by spot welding a spider 24 extending transversely across the tube. Spider 24 provides a bearing 25 for screw rod 26. Collars 33 fixed to rod 26 prevent axial movement thereof. Threadedly mounted on screw rod 26 is a diaphragm or obstruction 2'! which is slidably mounted in tube 23. Obstruction 2? prevents the flow of gas by it in tube 23. The lower end of screw rod 25 is provided with a head 28 which is outside of the muffler. In the use of the muiiler of 5, resonance with the impulses received from the engine can be avoided by adjusting the location of obstruction 27 in tube 23. This changes the natural period of vibration of the gas in the mufiier. Obstruction 21 can be set in a continuously varied position in tube 23. In this respect the muflier of Fig. 5 is different from the mufller of Fig. 6. In the latter mufiier, obstruction 29 can be set only at predetermined locations in tube 30. For most conditions this is a sufficiently flexible adjustment to overcome resonance. Tube 3!) i provided with sets of screw holes 3| in spaced positions along its length. Obstruction 29 has threaded holes which can be set in register with screw holes 3|, and when so set, screws 32 can be inserted to hold the obstruction in place in tube 3%. The clot and dash lines show how obstruction 29 could be set in another position. Gas escapes through unocculpied screw holes 3i increasing turbulence thereby in spiral member M.

The :casing 35 of Fig. 8 is formed with a spiral groove 34 into which the outer edge of spiral member i l fits. This gives said member especial rigidity.

I claim:

1. A mL tller for an internal combustion engine, including a casing enclosing an elongated chamber, a resonance tube extending longitudinally through said chambenbafliemeans alongside said tube extending longitudinally in said chamber, said casing having an opening therein at one end of the chamber fOr receiving the gas from the engine, said tube having an opening therein inside of the casing near the receiving end of the chamber, said casing having an opening therein at the opposite end of the chamber for the discharge of the gas passed through the bafiie means, said tube being closed off against the passage of gas therethrough at a location a substantial distance toward the discharge end of the chamber from the opening at the receiving end of the tube, gas received at the opening in the casing at the receiving end of the chamber passing in part directly through the baflle means to the discharge opening and in part through the tube to said closed location, being reflected back therefrom and out said tube orpening into the baiile member.

2. A muiiler for an internal combustion engine including a casing enclosing an elongated chamber, a resonance tube extending longitudinally through said chamber, spiral means about said tube extending longitudinally in the chamher, said chamber and tube receiving at one end the gas from the exhaust of the engine, the tube having an obstruction against the passage of gas therethrough at a substantial distance from its receiving end, part of the gas received from said exhaust passing directly through the spiral means to the outlet end of the casing, another part of the gas after entering the tube traveling a substantial distance through it to the obstruction from whence it is sent back again out of the tube to pass through the spiral means to the outlet end of the casing.

3. A mufiler for an internal combustion engine including a casing enclosing a chamber, a resonance tube in said chamber, bafile means between the tube and the casing, said chamber and tube receiving at one end the gas from the exhaust of the engine, said tube being closed off at a substantial distance from its receiving end, part of the gas received from the exhaust passing directly through the baflie means to the outlet end of the casing, another part of the gas after entering the tube rebounding from where it is closed to pass out the receiving end of the tube and through the baiile means to the outlet end of the casing.

4. A muffler for an internal combustion engine including a casing enclosing a chamber, a resonance tube in said chamber, bafile means in the chamber, said chamber and tube receiving at one end the gas from the exhaust of the engine, means for closing off the tube, and means for setting the closing off means at diiferent positions along the length of the tube, part of the gas received from the exhaust passing directly through the baflie means to the outlet end of the casing, another part of the gas after entering the tube being sent back again out of the tube to pass. through the baiiie means to the outlet end of the casing.

5. A muflier for an internal combustion engine, including a casing enclosing an elongated chamber, a resonance tube extending longitudinally through said chamber, baffle means alongside said tube extending longitudinally in said chamber, said tube extending through the casing with an opening for receiving the gas from the engine at one end of the chamber, said tube having an opening in its side inside of the casing near the receiving end of the chamber, said casing having an opening therein at the opposite end of the chamber for the discharge of the gas passed through the bafiie means, said tube being closed ofi against the passage of gas therethrough at a location a substantial distance toward the discharge end of the chamber from its side opening, gas, received by the tube from the engine, passing in part out said side opening directly through the baflle means to said discharge opening and in part continuing through the tube to said closed location, being reflected back therefrom and out the side opening in the tube into the baffle means.

6. A muflier for an internal combustion engine including a casing enclosing an elongated chamber, a resonance tube extending longitudinally through said chamber, baffle means alongside said tube extending longitudinally in said chamber, said tube extending through the casing with an opening for receiving the gas from the engine at one end of the chamber, and extending through the casing at the opposite end of the chamber for the discharge of the gas outside of the casing, said tube having an opening in its side inside the casing near the receiving end of the chamber and another opening in its side near the discharge end of the chamber, said tube being closed oif against the passage of gas therethrough at a location a substantial distance away from the opening which is near the receiving end of the chamber, gas, received by the tube from the engine, passing in part out the side opening of the tube near said receiving end directly through the baffle means, then into the side opening of the tube near said discharge end and out of the tube to the outside of the casing,

another part of the gas continuing through the tube to said closed location, being reflected back therefrom and out the side opening of the tube near the receiving end into the baffle means.

7. A muflier for an internal combustion engine including a casing enclosing a chamber, a resonance tube in said chamber, baflie means extending through the chamber, said chamber and tube receiving at one end the gas from the exhaust of the engine, means movably mounted in the tube for closing off the tube, and means for setting the closing 011 means at different positions along the length of the tube, said setting means extending through the casing to the outside thereof for manual adjustment on the outside, part of the gas received from the exhaust passing directly through the baffle means to the outlet end of the casing, another part of the gas after entering the tube being sent back again by reflection from said closing off means and out of the tube to pass through the baflle means to the outlet end of the casing.

8. A muflier for an internal combustion engine including a casing enclosing a chamber, a resonance tube in said chamber, baflie means extending through the chamber, said chamber and tube receiving at one end the gas from the exhaust of the engine, the tube extending through the casing at the opposite end of the schamber, the gas being discharged from said opposite end of the chamber, means movably mounted in the tube for closing off the tube, and means for setting the closing off means at different positions along the length of the tube, said setting means extending through the tube and out its end at said opposite end of the chamber for manual adjustment on the outside of the chamber, part of the gas received from the exhaust passing directly through the baflie means, and out of the chamber at its discharge end, another part of the gas going through the tube until reflected back by the closing oiT means to pass out of the tube to join the gas passing through the baffle means.

9. A mufiler for an internal combustion engine including a casing enclosing a chamber, a resonance tube in said chamber, bafiie means extending through the chamber, said chamber and tube receiving at one end the gas from the exhaust of the engine, the tube extending through the casing at the opposite end of the chamber for the discharge of the gas outside of the casing, said tube having an opening in its side inside of the casing near the discharge end of the chamber, means movably mounted in the tube for closing oif the tube, and means for setting the closing ofi means at different positions along the length of the tube, said setting means extending through the tube and out of its discharge end for manual adjustment on the outside of the casing, part of the gas received from the exhaust passing directly through the bafiie means, then into the side opening of the tube near said discharge end and out of the tube to the outside of the casing, another part of the gas going through the tube until reflected back by the closing off means to pass out of the tube to join the gas passing through the baflie means.

10. A muffler for an internal combustion engine including a casing enclosing a chamber, a resonance tube in said chamber, baflle means in the chamber, said chamber and tube receiving at one end the gas from the exhaust of the engine, means for closing ofl the tube having an internally threaded portion, and a screw rod extending along the tube upon which said portion is threaded, the rotation of the rod varying the position of the closing oif means along the inside of the tube, part of the gas received from the engine passing directly through the baflie meansto the outlet end of the casing, another part of the gas after entering the tube being reflected back by the closing oft means to pass out of the tube to join the gas passing through the bafiie means.

11. A mufiler for an internal combustion engine including a casing enclosing a chamber, a resonance tube in said chamber, baffle means in the chamber, said chamber and tube receiving at one end the gas from. the exhaust of the engine, means for closing off the tube movable therein, said tube having provision at a plurality of spaced fixed locations for holding the closing off means in position in the tube, part of the gas received from the engine passing directly through the bafile means to the outlet end of the casing, another part of the gas after entering the tube being reflected back from the closing off means to pass out of the tube to join the gas passing through the bafiie means.

MORRIS KATCHER.

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