Abstract: A sound absorber/insulator in a motor vehicle is constructed of outer layer nonwoven scrims, perforated films, and a fill material core, which are typically fibers or foams. Fibers could be of a nonorganic nature such as glass, or an organic one like polyester or cotton. Foams could be of open cell polyurethane chemistry. The materials are enveloped in a thermoforming process wherein all layers are substantially adhered to each other. The fill material is responsible for sound attenuation whereby a higher weight input provides additional attenuation benefit. Specialized technical nonwoven scrims can also be used to enhance the sound attenuation where required. Increasing absorption properties by adding weight or using highly technical nonwovens is costly and results in a weight penalty.

Abstract: A muffler for a motor vehicle has a muffler housing with a packing void into which an envelope containing a loose fill material is installed during assembly. The envelope contains elongated strands of continuous strand fiberglass, woven as a fiberglass mesh fabric, and having a thin organic polymer coating to reduce sliding and/or being formed with a Leno or gauze weave structure. The envelope is joined at one or more stitched seams, preferably with cotton thread, to enclose a volume. The volume is packed with uncoated continuous strand fiberglass roving, filling the volume to complement the packing void. The cotton thread and the thin polymer coating are consumable by hot gas in the exhaust path, but produce minimal smoke and odor due to their compositions and the small proportion of the packing volume and surface area that the consumable portions occupy.

Abstract: A muffler for a motor vehicle has a muffler housing with a packing void into which an envelope containing a loose fill material is installed during assembly. The envelope contains elongated strands of continuous strand fiberglass, woven as a fiberglass mesh fabric, and having a thin organic polymer coating to reduce sliding and/or being formed with a Leno or gauze weave structure. The envelope is joined at one or more stitched seams, preferably with cotton thread, to enclose a volume. The volume is packed with uncoated continuous strand fiberglass roving, filling the volume to complement the packing void. The cotton thread and the thin polymer coating are consumable by hot gas in the exhaust path, but produce minimal smoke and odor due to their compositions and the small proportion of the packing volume and surface area that the consumable portions occupy.

Abstract: A muffler for a motor vehicle has a muffler housing with a packing void into which an envelope containing a loose fill material is installed during assembly. The envelope contains elongated strands of continuous strand fiberglass, woven as a fiberglass mesh fabric, and having a thin organic polymer coating to reduce sliding and/or being formed with a Leno or gauze weave structure. The envelope is joined at one or more stitched seams, preferably with cotton thread, to enclose a volume. The volume is packed with uncoated continuous strand fiberglass roving, filling the volume to complement the packing void. The cotton thread and the thin polymer coating are consumable by hot gas in the exhaust path, but produce minimal smoke and odor due to their compositions and the small proportion of the packing volume and surface area that the consumable portions occupy.