IL28618A - Muffler device - Google Patents

Description

MUFFLER DEVICE 7i j? nj?nwn7 ipnn This invention relates to muffler devices for the exhaust of internal-combustion engines and more particularly to a muffler device embodying improvements over that U.S. disclosed in my prior/ Patent No, 3,166,152 granted January 19, 965.

The principal object of the invention is to provide a muffler in which the pulsations of the exhaust gases as received from the engine may be first asynchronously imposed on each other at an increasing frequency rate and thereafter, also asynchronously, may be imposed on each other at a decreasing frequency rate whereby the pulsations tend almost wholly to cancel themselves out with resultant substantially complete elimination of the vibrations causing the noise of an engine exhust.

Other objects of the indention are to provide a muffler of the foregoing character which is composed of few parts, all of which are united into a unitary structure, which is much smaller in size for a given volume of exhaust gases than mufflers presently in common use, which imposes a minimum ofback pressure on the exhaust gases, and which is economical to manufacture.

In the accompanying drawings :- Figure 1 is a reduced scale, perspective view of a muffler constituting a presently preferred embodiment of the invent!on{ Figure 2 is a greatly enlarged, exploded view of the muffler as shown in Figure 1 , taken as though the muffler had been cut apart on a plane coincident with the centre lines of the inlet and outlet port nipple components; Figure 3 is a medial sectional view on a slightly smaller scale than Figure 2 taken in the plane including the line B-B of Figure 1 and extending transversely of the centre lines of the two port nipple components; Figure is a sectional view in the same scale as Figure 3 taken on the staggered line A-A of Figure 1 ; and Figure 5 is a perspective view of a centrally disposed tubular component of the device* Referring to the drawings, the muffler body structure 1 comprises a cylindrical body portion 2 formed by a circular, thin metal wall 3 having an oval opening 4 extending therethrough through which an inlet nipple 5 extends tangentially with respect to the wall 3 from a point exteriorly of said wall and of sufficient length to permit connection to an exhaust conduit leading from an engine, said nipple extending through the wall 3 to a point within the muffler body which is slightly short of a centre medial plane of said body member extending in a direction normal to the centre line of the nipple component. The wall 3 at a point diametrically opposite the opening 4- is provided with a similar opening 6 through which an outlet nipple component 7 extends similarly tangentially to the nipple 5 and in the same direction circularly of the body wall 3 as the nipple 5> said nipple extending from a point within the body which is slightly short of the plane referred to with respect to the inner end of the nipple 5 through the wall 3 and terminating exteriorly of the wall in a length sufficient to permit connection of a tail pipe or the like if desired. The nipples 5 and 7 are rigidly connected to the wall 3 by welding or brazing.

The enclosure of the muffler body is completed by opposed outwardly pointed conical end wall members 8 and 9 having edge portions which overlap the edges of the body member 3 and said end wall members are brazed or welded to the body member 3 to effect a unitary structure of the body and the end members. All of the above described body forming components are formed of suitable sheet metal stampings and lengths of tubing and, as noted, are of simple design, wherefore the cost of manufacture is kept at a minimum.

The interior of the body structure is divided into two compartments of substantially identical configuration by a centre wall member 10 comprising a disk of metal of slightly oval configuration v/hich is placed within the body member 3 so that with respect to the internal end of the inlet nipple 5 it is at the side thereof adjacent the end member 8 and with respect to the inner end of the outlet nipple 7 it is at the side of said nipple which is adjacent the end member 95 it being noted particularly in Figures 3 and 4 that the inner ends of the nipples 5 and are slightly flattened as at 5' and ', respectively, to enable the circumferential edge of the end wall member 10 to be retained within the confines of the body wall member 3· This partition wall 10 is secured at various points along its circumference to the interior surface of the body member 3 by appropriate spot welds. For identification, the compartment formed by the wall 10, a portion of the body member 3 and the end member 8 and which is in communication with the inner end of the inlet nipple 5 will be designated as the inlet compartment 11 and the corresponding compartment which is in communication with the outlet Communication between the compartments 11 and 12 is afforded by a tube 13 of substantially the same diameter . as the outlet and inlet nipples and which is disposed axially of the muffler body and which extends through an opening 13 ' in the wall 10 and being welded in place therein. The end 14- of the tube which is disposed in the inlet compartment 11 is cut away at opposite sides as at 15 » to form a pair of diametrically opposite leg portions 16, 16 which are welded to the inner face of the end member 8. Adjacent the edge surfaces of the end 14, the wall thereof is provided with a plurality of small holes 17 extending therethrough.

The opposite or outlet end 18 of the tube 13 terminates in the compartment 12 spaced from the inner wall of the end member 9 as best shown in Figures 3 and 4· and adjacent to said end the tube is provided with a plurality of small holes 19 extending therethrough which are generally similar to the holes 17 at the opposite end of the tube.

It is again to be noted that the entire muffler assembly is composed of what is essentially only five different parts, since the two end members and the nipple components are identical, and that all of the parts are individually of simple design and capable of economical manufacture. Still further, it is to be noted that all of the parts are welded together to form a construction which for all purposes may be regarded as being integral.

In operation, the exhaust gas entering the compartment 11 through the inlet nipple 5 must exit through the tube 13 to the outlet compartment 12 and thence through the outlet nipple 7 to atmosphere. Since the gas enters the muffler body tangen ially of the wall of the body portion 3 the initial motion of the gas within the compartment 11 is circular therein and since the entrant end of the tube 13 is at the reduced diameter portion of the conical end wall, the rate rotation of the gas as it approaches this smaller diameter end and gradually asynchronously increases. Since the gas coming from the engine is delivered in a pulsating condition deriving from the operation of the engine, these pulsations within the inlet compartment 12 impose themselves on each other and tend to cancel each other out. Moreover, since the gas enters the tube 3 from opposite sides thereof the pulsations also tend further to oppose each other and to cancel each other out as they enter this tube. The progress of the gas going througli the tube 13 is accompanied by an intense whirling motion therein deriving from the nature of the entrance of the gas into the inlet chamber 11 and emerging from the end 18 of the tube 13; the gas and its whirling motion must be slowed down by reason of gradually reaching the diameter of the body portion 3 in which the inner end of the outlet nipple is located. This is also an asynchronous change of rate of the whirling motion of the gas and for all practical purposes, completes the elimination of the pulsation of the gas resulting in a uniformly steady and noiseless emission of the gas from the muffler. 17 Referring now to the holes and 19j the exact manner in which these holes operate on the whirling gas is admittedly not known. Repeated experiments have shown, however, that adding these holes has measurably contributed to the silencing effect of this muffler. Several theories have been advanced and the most probable one seems to be that the holes l 1 by permitting a portion of the gas to enter the tube radially in addition to the axial flow therethrough, tend to oppose and reduce the velocity of rotation of the gas as it traverses the tube 13 and that similarly, the holes 9 permit a portion of the gas traversing the tube 3 to escape radially through said holes into the outlet compartment 12 and correspondingly assist in further reducing this whirling movement of the gas in that chamber or compartment.. Additionally, it is probable that the holes ~=L and 19 (particularly the holes serve to destroy any tendency to form a vacuum pocket in the gas flow as it changes its direction of movement flowing around the thin edge of the tube 13 as it enters the tube at high velocity. As in my said prior patent, there are no baffles or other obstructions to the flow of exhaust gas, wherefore, the possibility of deleterious back pressure is practically eliminated.

While in the foregoing specification there is disclosed a presently preferred embodiment of the invention the invention is not to be deemed to be limited to the precise details of construction thus disclosed by way of example and it will be understood that the invention includes as well, all such changes and modif cations in the parts and in the construction, combination and arrangement of parts as shall come within the purview of the appended claims„

Claims (6)

1. A muffler for internal-combustion engines, which includes a generally cylindrical, hollow body having opposed, outwardly pointed conical ends, a partition within said body dividing said body into an inlet compartment defined by one side of said partition, a portion of the circular body and one of said ends, and an outlet compartment defined by the other side of said partition, the remainder of said circular body and the other of said ends, an inlet nipple extending generally tangentially into said body at a point between said ends and communicating with said inlet compartment, an outlet nipple extending from said body in the same tangential direction as said inlet compartments.

2. A muffler for internal-combustion engines as claimed in claim 1 in which said partition constitutes a flat plate closely fitting the interior wall of the cylindrical portion of said body and extends from one side of said inlet nipple to the opposite side of said outlet nipple.

3. A muffler for in ernal-combustion engines as claimed in claim 1 in which said conduit means through said partition comprises a tube having an inlet orifice means disposed adjacent the apex of the conical end wall of the inlet compartment and an outlet orifice disposed adjacent the apex of the conical end wall of the outlet compartment.

4. -, A muffler for internal-combustion engines as claimed in claim 3 in which said tube includes pluralities of holes extending through the wall thereof adjacent the respective orifices thereof.

5. A muffler for internal-combustion engines as claimed in claim 3 in which said tube has one end thereof fixedly mounted on the conical end wall of said inlet compartment and the midlength portion thereof fixedly mounted in said partition, and in which the end of said tube within said outlet compartment is spaced from the conical end wall of said outlet compartment.

6. A muffler for internal-combustion engines substantially as described with reference to the accompanying drawings. SEC