Muffler

A muffler for use in conjunction with an internal combustion engine for reducing the noise level of exhaust gases emitted by the engine, the muffler comprising an elongated diffusor having the shape of a truncated cone, a smaller diameter defining an upstream end of the diffusor and a larger diameter defining a downstream end of the diffusor;

• a frustoconically shaped, perforated shell having an upstream, large diameter end coupled to the downstream end of the diffusor and a downstream, smaller diameter end, the shell including perforations;
• a generally cylindrical conduit having a first end attached to the downstream end of the shell, extending from the shell in a downstream direction, and including an opening adjacent a second end of the conduit;
• a housing surrounding the shell and the conduit and extending from the diffusor to a discharge end of the muffler;
• a sound absorbing material disposed between the shell and the housing;
• a baffle disposed within the housing to seal the opening and an annular space between the conduit and the housing from the discharge end and at least one tube oriented substantially parallel to the conduit, extending past the baffle and having a first, intake end proximate the first end of the conduit and a second, outlet end, communicating with the discharge end so that exhaust gas entering the diffusor can travel through the conduit tube, the opening therein, the annular space and thereafter through the tube to the discharge end of the muffler.