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R&D LABS

OUR R&D LABS

NOISE, VIBRATION & HARSHNESS

How can tyre road noise be reduced effectively? Finding this out is the job of the Noise, Vibration & Harshness (NVH) Lab team. This is an important task given that the interaction of tyres with the road is one of the main contributors to traffic noise. The ideal “silent” tyre is a heavy and smooth slick which, however, performs less well in other aspects compared to a well-balanced summer or winter tyre in wet conditions.

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In an anechoic chamber, the tyres run at different speeds on various replicated road surfaces while highly sensitive microphones record the generated noise. Tyre load and camber can be adjusted to simulate different vehicles and driving conditions.

Noise, Vibration & Harshness (NVH) Lab

Using suitable software, two aspects of the tyre’s NVH performance are then analysed. The first is if the road surface-dependent rolling noise − the noise directly emitted by the tyre into the environment – meets development  targets and will meet, or fall below, statutory noise protection requirements (EU Tyre Label). The second aspect of tyre performance is how it absorbs vibrations such that the minimum amount of noise is transmitted into the vehicle interior via the chassis.

A growing proportion of noise tests involve tyres for electric vehicles which must have particularly low rolling resistance and be lightweight in order to increase the e-vehicle’s range. The NVH Lab provides important insights into how to resolve possible conflicting goals in the product development process.

 

NVH Lab staff work closely with tread designers and are involved from the initial drafts of a design.

 

The characteristics of the inner construction and sidewall layout of a tyre also impact noise performance, as do the weight and material properties selected.

Above and beyond the purely objective aspects of noise performance, the NHV Lab also works on sound design. This is because it is not just the sound level which determines whether a noise is perceived as unpleasant, but also its sound quality. One well known example of this are truck tyres which can have a characteristic “howl” at certain speeds and on particular road surfaces.

The higher level of noise from winter tyres can also be transformed into a more pleasant sound. Moreover, the perception of sound differs from continent to continent, so tyre noise is adapted to the different markets in Asia, North and South America.

This means the NVH Lab not only works with other R&D  departments but also actively engages with customer wishes brought to its attention by marketing and sales teams around the globe.

Noise, Vibration & Harshness (NVH) Lab