Inline high frequency fiber silencer
A high frequency attenuating device for an air flow induction system of a vehicle employing a thermoformed fibrous mat of any shape that fits robustly inside the duct. The dissipative nature of the fibrous mat helps in achieving broadband attenuation in the high frequency regime. The ability to manufacture the fibrous mat into any shape helps with restriction, targets different attenuation bands, and makes it more feasible to manufacture. Hybrid solutions are possible when combined with low frequency perforated silencers or high frequency QWT arrays injection molded onto them.
1. A high frequency attenuating device for a vehicle air induction system comprising: a thermoformed or compression formed in-line silencer securable within said flow induction system formed from a mat of fibrous material with a total basis weight of about 800-1000 grams per square meter, said mat shaped into a double-roll configuration comprising a first consolidated nesting location leading to a first outer wall panel, a second consolidated nesting location leading to a second outer wall panel, a third consolidated nesting location leading to a third outer wall panel, a fourth consolidated nesting location leading to a first inner wall panel, a fifth consolidated nesting location leading to a second inner wall panel, a sixth consolidated nesting location leading to a third inner wall panel, and a seventh consolidated nesting adjoining said first consolidated nesting location, wherein said first nesting location couples to said fourth and said seventh nesting location, said second nesting location couples to said fifth nesting location, and said third nesting location couples to said sixth nesting location, arranging said mat into a circular shaped outer wall having a proximal end and a distal end with at least three inner panels extending therebetween, wherein said in-line silencer is constructed and arranged to attenuate high frequency by a dissipative approach.
2. The high frequency attenuating device according to claim 1 wherein said in-line silencer is tuned to target a high frequency by modifying physical and material properties of said fibrous material.
3. The high frequency attenuating device according to claim 1 wherein said in-line silencer is constructed and arranged to target octave bands.
4. The high frequency attenuating device according to claim 1 wherein said in-line silencer inner walls are in-line with the outer wall to minimize airflow restriction.
5. The high frequency attenuating device according to claim 1 including a housing for positioning of said in-line silencer.
6. The high frequency attenuating device according to claim Y, wherein said housing or end closure includes air deflectors for steering oil droplet laden air away from said fibrous material.
7. The high frequency attenuating device according to claim 1 including spacers formed in said outer wall along said first, second and third nesting locations, wherein said spacers centrally position said in-line silencer in said housing.
8. The high frequency attenuating device according to claim 1 wherein said in-line silencer is combined with a perforated silencer, annular resonator, QWT array, or a combination thereof to target attenuating frequency ranges.
9. The high frequency attenuating device according to claim 1 wherein said fibrous material provides hydrocarbon adsorption/desorption.
10. The high frequency attenuating device according to claim 1 wherein said fibrous material outer wall is perforated for acoustic tuning.
11. The high frequency attenuating device according to claim 1 wherein a portion of said fibrous material includes oleophobic materials or coatings.
12. The high frequency attenuating device according to claim 1 wherein a portion of said fibrous material includes oleophilic materials or coatings constructed and arranged to draw out oil retained therein.