Muffler packing method and apparatus

In combination, a muffler and a loose packing material,

• wherein the packing material is at least partly confined by a mesh to conform to a cavity of the muffler, the mesh being an openwork structure having a minimal acoustic effect, whereby the muffler has an original tune substantially the same as its long term tune;
• wherein the mesh is at least partly made of a consumable material and is consumed by heat with operation of the muffler, leaving substantially only the packing material in the cavity after consumption of the mesh;
• wherein the consumable material of the mesh comprises a thermoplastic polymer material and the mesh is shaped as a bag that is substantially closed and conforms the packing to a chamber of the muffler;
• and,
• wherein the muffler comprises a plurality of stamped plates, the plates having protrusions bearing toward one another and wherein the bag is shaped to hold the packing material clear of the protrusions.

A method of manufacturing a muffler comprising the steps of:

• providing at least two parts of a muffler casing defining a chamber for a loose packing material, the casing having at least one of a seam and an internal protrusion between the at least two parts;
• at least partly confining the loose packing material in a mesh forming an openwork structure at least partly complementary to the chamber;
• placing the loose packing material as confined by the mesh between two of said parts of the muffler casing, such that the mesh material holds the packing material clear of said at least one of the seam and the protrusion;
• and,
• assembling the two parts of the muffler casing with the confined packing material therein.