Clean burn muffler packing with stitched fiberglass envelope

A muffler to be mounted along an exhaust path of an internal combustion engine, comprising:

• a muffler housing assembled to define a packing void that is exposed to the exhaust path, the packing void carrying packing formed with an envelope containing a loose fill material;
• wherein the envelope comprises a sheet material including elongated strands of continuous strand fiberglass forming a fabric of woven fiberglass mesh, the envelope including at least one seam at which edges of the sheet material are joined to enclose a volume;
• wherein the loose fill material within the envelope comprises continuous strand fiberglass in elongated strands, the loose fill material expanding the envelope and filling the volume so as to complement the void;
• wherein a low smoke polymer coating comprising an acrylic resin is provided on the strands forming the fabric in an amount of about 5 to 20% by weight of the strands and the coating in combination, wherein the coating limits sliding of strands that engage against one another in the weave;
• whereby the coating is consumable by hot gas in the exhaust path with minimal production of smoke and odor.

A method for manufacturing a muffler, comprising:

• providing elements of a muffler housing that when assembled define a packing void configured to be exposed to an exhaust path;
• forming a pattern in sheet material for an envelope, the sheet material including elongated strands of continuous strand fiberglass fabric in a woven fiberglass mesh;
• joining the sheet material along at least one seam at which edges of the sheet material are joined such that the sheet material is formed into the envelope and partly encloses a volume;
• packing the envelope with a loose fill material comprising continuous strand fiberglass roving, the loose fill material expanding the envelope such that the volume substantially complements the void;
• wherein the sheet material for the envelope comprises a low smoke polymer coating on the strands forming the fabric, with an acrylic resin on the strands in an amount of about 5 to 20% by weight of the strands and the coating in combination, wherein the coating limits sliding of strands that engage against one another in the weave;
• wherein the continuous strand fiberglass roving is substantially uncoated;
• placing the packed envelope into the void so as to confine the loose fill material in the void, and assembling the elements of the muffler housing over the void.