Abstract: The present invention provides a muffler which has an outlet tube with a funnel shaped element having a large diameter end positioned in an expansion chamber and conically tapering to a junction with a cylindrical neck element extending into an inlet end of an outlet tube. An inlet tube is supported by an outer shell which also supports the outlet tube. The inlet tube is attached to the outer shell by a first partition and a first end cap, forming a tuning chamber. The outlet tube is attached to the outer shell by the funnel shaped element and a second end cap, forming an outlet chamber. A space defined by the distance between the first partition and the second partition and the geometry of the outer shell forms an expansion chamber. The three different chambers serve to either tune or quiet the exhaust coming from an internal combustion engine, and the funnel shaped element serves to smooth the flow of exhaust from the inlet tube to the outlet tube.

Abstract: The present invention provides an acoustic muffler for attenuating sound waves of the exhaust gas of an internal combustion engine including a shell, a plurality of walls closing both ends of the shell and dividing an interior of the shell into a plurality of chambers. The plurality of chambers include a first chamber having a sound absorbing material disposed therein. An imperforate pipe extends between the walls of the first chamber. Preferably, the plurality of chambers also include a second and a third chamber communicating with the imperforate pipe. Furthermore, a fourth chamber communicates with the second chamber.

Abstract: An automotive muffler has an end header with two bushing receiving openings and is used with a gas flow bushing assembly comprising a bushing to fit in one of the openings and a flange to clamp the bushing to the header and cover the other opening in the header.

Abstract: A muffler for reducing the audible noise level of exhaust gases emitted by combustion engines has an inlet tube with a patch of louvers or perforations and is arranged so that all or substantially all the gas flowing through the muffler is forced through the patch into an expansion chamber from which it flows by either cross bleeding through a patch of louvers or perforations into an outlet tube or to a chamber opening into the inlet end of the outlet tube. A "splitter" partition may be used to control flow through the louvers and provide additional attenuation. An imperforate portion of the inlet tube is used as a driven tuning tube with a resonator chamber to form a Helmholtz low frequency attenuation system, the performance of which may be improved in some cases by use of an orifice in a wall of the resonator. Also disclosed is a muffler in which all the gas flows through a louver patch in the outlet tube and an imperforate part of the outlet tube is used as a part of an aspirating type Helmholtz system.

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.