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Solving the problem by preventing air column resonance
An air intake duct takes in outside air and delivers it to the engine
through an air cleaner. Since air column resonance in an air path
including a duct increases intake noise, a noise eliminator such as
a resonator and a side branch are installed on a duct and an air cleaner.
Auto manufacturers asked us to reduce or remove a noise eliminator
because it contributed to saving space and reducing the weight of
a car. TG responded to the request by devising a completely new idea
that instead of eliminating occurring air column resonance, we should
develop an air duct with no air column resonance in the first place,
so that a noise eliminator would not be necessary at all.
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An optimal design for a porous part enables
us to cut noise, lower cost, and prevent pressure loss
In noise elimination, air column resonance generated in an air path
is contained by letting pressure out through the porous material of
a duct. Porous materials and their allocation optimal for an air intake
system are determined by sound and aerodynamic simulation.
This effort has led to total removal of noise eliminators and decreased
noise for the whole air intake system.
A non-reflective duct was introduced to the Estima in spring 2000.
It has been improved further since then, and adopted to mass-produced
cars of various kinds. |
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