Underbody acoustic insulation blocks reflected road noise
Vehicle underbody acoustic insulation doesn’t just help to prevent noise from the vehicle’s own transmission from escaping into the surrounding environment; coupled with floor insulation in the interior cabin, it can be instrumental in shutting out noise reflected back up from the surface of the road.
This is important because, although underbody acoustic insulation is effective in minimising the escaping noise from the drivetrain, there is still unavoidable noise produced due to the rolling contact between the tyres and the road surface.
An article published in Emerging eLearning Technologies and Applications notes how different road surfaces have different effects on tyre noise – and how some are more likely than others to allow that noise to be transmitted back towards the vehicle, or to other road users and passers-by.
“The most common source of noise in the environment is traffic,” the authors write. “Noise emissions caused by traffic are highly dependent on the properties and characteristics of the road surface, especially its structure and porosity.
“Both of these properties influence rolling noise connected with the movement of tyres on the road. Moreover, the porosity of the road may affect sound propagation, especially near the surface.”
By equipping the underbody with acoustic insulation, vehicles can be protected against this propagated road noise, while also preventing their own engine and exhaust noise from escaping downwards to add to the total background volume level.