Noise, vibration, and harshness

Noise, Vibration, Harshness ( Deutsch.: noise, vibration, harshness ) or short NVH is now also in German-speaking countries the term for audible as noise or vibration perceptible vibrations in motor vehicles or machinery. Roughness or harshness refers to both audible and tactile transition area in the range of 20 Hz to 100 Hz Generally speaking, the cause of NVH is the local force application of a vibration source in vibration transmitting media ( such as mechanical structures in motor vehicles). The reasons for vibrations are actually usually stick-slip effects ( self-excited friction vibrations ) in the vehicle, which are either intentional side effects of friction, or unintentionally arise in solid friction and lead to radiation of structure-borne noise and ultimately audible airborne sound. Typical examples of NVH are squeaking brakes, rattling wipers, gear whine, clutch judder or noise from the vehicle air conditioning.

In practice, such effects are evaluated by the automotive manufacturers and suppliers, in order to estimate the risk of complaints and ensure the acceptance of the product in the vast majority of customers. The assessment is carried out, for example, depending on these factors:

  • Driving situation: If the noise only occur when the driver is in a stressful situation, he makes appropriate sounds less true.
  • The driver's expectations: Squealing brakes, wipers and brake rattling noise generated during ABS activity are more readily accepted than noise in ventilation. Certain driving sounds are accepted by sports car drivers, while limo driver claim the same noises.
  • Sensitivity of the customer group: experience as to when the majority of customers NVH even noticed and when the tolerance threshold is exceeded for complaint.

To be distinguished from measures against NVH is also a common sound design of engine and exhaust noises, slamming doors or active electric motors. When it comes to NVH avoid vibrations that affect the driving comfort, the sound design is about optimizing expected audible noise in terms of ideas and associations of the buyer.

Manufacturer

Among the largest European automotive NVH components, such as sound absorbers and insulation include:

  • Borgers
  • Autoneum ( ehm. Rieter )
  • Magna Seating
  • Pelzer Group
  • Vibration
  • Structure-borne noise
Coupling Consumer complaint
606985
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