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Automobile Noise Reduction Duct

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Automobile Noise Reduction Duct

French Renault laboratory has begun to research to resolve DUCT Resonance problem by Plastic Duct of intake system since the end of 1970s.

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Woven Duct

  • French Renault laboratory has begun to research to resolve DUCT Resonance problem by Plastic Duct of intake system since the end of 1970s.
  • Surprising solution, Woven Duct(Material : composed of 'cotton yarn+steelwire+coatingliquid') began to adapt a car produced in Europe from the end of 1980s after finishing development .
  • Also it introduced in Korea in 1997, Joint-venture of technology & production, Korea Wecostawas founded, adapted at Korean cars, exported Asia region.

Acoustic Duct

  • Woven Duct Upgrade (Material : composed of 100% Polymer)
  • Goods & production development of Acoustic Duct that is eco-friendly, more improving function is developed from the middle of 1990, present, adapts all European models, has international patent.
  • Korea Wecostaintroduced technology for Acoustic Duct and finished developments in 2002.
  • Starting with application for mass production of Hyundai'.s NF model in 2004 and applies new development model.

PET(Polyethylene terephthalate) Duct

  • Wecostahas finished PET Duct development, which an upgraded version of Acoustic Duct in 2010. This project is related with the global model of GM and there is supply PET duct of these models to China, Uzbekistan, Thailand and India., etc. through a global business network.
  • Korea Wecostajust sub-assemble the parts and supplying them to GMK.
  • In case of Woven & Acoustic Duct, application for specification had limits because there is a limit in shape realization by cylindrical structural characteristics.
  • Korea Wecosta, we have completed the Development of Manufacturing Techniques the possibility of application in various shapes.
  • The Manufacturing Techniques is expected to be implemented in 2013 mass production, which are being applied the model MD F/L in Hyundai Motors.


How Porus Ducts Reduce Noise
NoiseIf you listen to a sea shell by bringing it against your ear, you can hear noise. Children say you can hear sea. In fact, it is not a reminiscence of the sea that is heard but the natural resonances that occur in any closed cavity containing a compressible fluid. (air in this instance) If, instead of a sea shell, you take a plastic or metal tube and bring it against your ear, you hear noise also even though it is open at two ends instead of one. This is because the air inside the tube is in a very confined volume as compared to that in open space and do its acoustic impedance is very high. In other words, the air inside the duct does not react like that of outside and behaves like a stiffer medium independently from the air outside of the tube. As a result, natural air movement inside the duct builds up resonances which can not be seen but can easily be heard.

How the resonances of a pipe can be eliminated
Resonances are pressure variations that self-generate in any confined cavity containing air pressure remains constant only where the duct is open. Against all its impervious surfaces, pressure varies with the pulsations.In order to prevent these pressure variations, it is necessary that all surfaces transmit any pressure variation. The porous duct is what achieves this. If you know to take a porous duct and bring it against your ear, you will hear no more extra noise than you hear without any duct or pipe against your ear.