The new EQS: the noise and vibration comfort
The EQS is the all-electric member of the S-Class family. This means that it must meet the highest expectations for acoustic comfort. The specifications therefore already defined a number of measures, including special acoustic foams in some of the profiles of the shell as well as the encapsulation of the eATS at the front and rear. The drive units are doubly insulated using rubber mounts. At the front axle this takes the form of a supporting frame, with a subframe at the rear axle.
Starting with the design of the electric powertrains (eATS), NVH (noise, vibration, harshness was a priority. The magnets inside the rotors are arranged in an NVH-optimised way (so-called sheet metal cut). This also reduces the use of rare earths. The shape of the winding, the so-called stator tilt, also supports vibration comfort, especially at low speeds. In relation to the permanent magnets of the rotor, the coils of the stator are obliquely wound. Otherwise, what is known as cogging torque could occur. This would lead to slight but unpleasant vibrations when driving very slowly.
In addition, the eATS have a special foam mat all around as an NVH cover. The lid of the inverter has a sandwich construction of three metal and plastic layers. The eATS are doubly decoupled from the body via elastomer bearings: At the front axle opposite a supporting frame and this against the body, and a rear axle carrier.
Highly effective spring/mass components provide continuous sound insulation from the cross-member under the windscreen to the floor of the boot. Acoustic foams are inserted into many carriers as early as the shell construction stage. Because the full-area main floor under the high-voltage battery is a component with a potentially high noise component, a new insulation part is used there. A foam sealed in foil, enclosed in the seal of the battery lid, is clamped between the battery and the floor and prevents excitation. In addition, the main floor is designed with beads for NVH reasons. These prevent resonance of the surface and thus the occurrence of a corresponding structure-borne sound. Two acoustic dividers in the very large tailgate reduce boom noise. These could be caused by roadway excitations and are favoured by the large volume of the cab including the bulkhead-free luggage compartment.
In addition, there are the measures of aeroacoustics, more on this in the specific Chapter.