Abstract: A sound-attenuating muffler for reducing the acoustic energy in an exhaust gas stream has an elongated cylindrical housing with a small ratio of diameter to length. Axially extending vanes are radially disposed to define an added number of flow passages. Exhaust gas enters an entry passage defined between two vanes, travels past a side-branch resonator and terminates in the entry nozzle of a Helmholtz chamber. The flow turns through a port in one of the vanes and enters a reverse-flow passage, also defined between two vanes, flows past a side-branch resonator and is reversed again through a port through another vane. A third side-branch resonator is provided in the exit region. The muffler may comprise two or more separate similar muffler sections defining such serpentine gas flow paths, and the exit region of an upstream section may then be continuous with the entry region of a downstream section.

Abstract: A muffler for an internal combustion engine includes a cylindrical casing having end plates closing the interior thereof. At least one baffle extending perpendicularly to the central axis of the casing is provided for dividing the interior of the casing into a front chamber and a tuning chamber. A tuning tube extending through the baffle places the front chamber into flow communication with the tuning chamber, and at least one exhaust gas inlet pipe extends into the front chamber through one of the end plates in coaxial relationship with the tuning tube. At least one exhaust gas outlet pipe is provided through the one end plate in parallel relationship with the inlet pipe. Furthermore, one or more openings are provided in the baffle in coaxial relation to the exhaust gas outlet pipe.

Abstract: For dampening exhaust gas noise a muffler contains two portions, of which one is adapted to take care of high frequency noise and includes dampening material, and the other is adapted to take care of low frequency noise and is devoid of such material. The latter portion includes an inner, perforated tube, a surrounding casing and wall means for subdividing the casing axially as well as transversely. The length of the tube is compatible with the lowest frequency of the noise to be divided, and the location of the wall means is selected as to form chambers of varying lengths compatible with other frequencies within the low frequency zone.The high frequency portion may be fitted concentrically around the low frequency portion, or may be located so as to form an axial extention thereby.The means communicating the low and the high frequency portions may include a radial diffusor.

Abstract: A silencer which may be arranged in place in an exhaust system of an internal combustion engine includes walls forming the main body of the silencer; a first separator supported by the walls to define a rear chamber therebetween; a second separator supported by the walls to define a first intermediate chamber between the walls and the first and second separators; a flame-extinguishing device supported by the walls to define a second intermediate chamber in combination with the walls, the second separator and the flame-extinguishing device as well as to define a front chamber between the walls and the flame-extinguishing device; an inlet pipe in fluid communication with the front chamber whereby an exhaust gas may flow from the inlet pipe into the front chamber; an outlet pipe in fluid communication with the first intermediate chamber whereby the exhaust gas may flow out of the first intermediate chamber through the outlet pipe; and an inner pipe having a plurality of apertures formed therein.

Abstract: A muffler for lowering the exhaust gas noise level of combustion engines has a Helmholtz resonator chamber and a single straight tube member that is provided with a perforated portion outside said chamber large enough for full flow through it of all gas flowing through the muffler, one end of the tube extending into the resonator chamber and the tube diameter, chamber volume, and length of the tube between said one end and said perforated portion being related to and dependent upon each other in accordance with the Helmholtz formula so that the resulting Helmholtz system attenuates a predetermined frequency when the muffler is placed in an exhaust system at or near the pressure antinode of that frequency.

Abstract: A muffler which does not require a low-frequency Helmholtz resonator includes an outer shell and first and second heads for closing the inlet and outlet ends, respectively, of the shell. First, second and third baffles are disposed internally of the shell and extend transversely therein. An outlet end chamber is defined between the inlet head and first baffle. A second chamber is defined between the first and second baffles. A third chamber is defined between the second and third baffles. An inlet end chamber is defined between the third baffle and outlet head. An inlet conducting tube extends longitudinally of the shell through the inlet head and the first, second and third baffles and opens into the inlet end chamber. An outlet conducting tube extends through the outlet head and the first, second and third baffles and opens into the outlet end chamber. An aperture in the first baffle acoustically couples the outlet end chamber and second chamber.