Abstract

A muffler of the expansion type comprises an inlet pipe and an outlet pipe connected with each other through a main body. Minimization of pressure pulsation is achieved by a variety of means including appropriately-located apertures in those portions of the walls of said pipes within said main body, an apertured partition within said main body so located that exhaust gas passes through said partition, and appropriate tapering of said pipes. A foamed, heat-resistant material may be positioned over said apertures in said walls of said pipes. Pipe constructions suitable for mass production and pipe-to-main body constructions free of the danger of separation during prolonged use are shown.