Muffler for internal combustion engines and method of manufacturing same

TLDR: In this paper, a central diffuser body is located within the outer casing substantially along the longitudinal centerline of the muffler, and a mounting plate connects the front and rear ends of the diffuser to the inlet and outlet pipes, respectively.

Abstract: A muffler for use with internal combustion engines or the like having improved sound attenuation capabilities together with lower back pressure. The muffler has an elongated outer casing connected to inlet and outlet pipes by inlet and outlet transition sections. A central diffuser body is located within the outer casing substantially along the longitudinal centerline thereof. Mounting plates connect the front and rear ends of the diffuser body to the inlet and outlet pipes, respectively, to hold the diffuser body in place. An inner casing is spaced from, and conforms to, the inner surface of said outer casing between transition sections. The inner casing and the side wall of the diffuser body are perforated. Porous or fibrous sound absorbing material is contained within the diffuser body and between the inner and outer casings. The cross-sectional areas of the inlet pipe and the ring between the inner casing and the diffuser body are preferably substantially equal.