The new EQE: aerodynamics

Apr 13, 2022
Stuttgart

For more than three decades, the aerodynamicists at Mercedes-Benz have been achieving top results. At present the EQS (V 297)[1] with a Cd value of 0.20, the A-Class Saloon (V 177) and the S-Class (V 223) with 0.22 are the world record-holders among series vehicles. The special simulation tools and the Mercedes‑Benz aero-acoustics wind tunnel commissioned in 2013 make a decisive contribution to this. The EQE also received its fine-tuning there. It achieves a very good Cd value of from 0.22 thanks to its one-bow design and extensive aerodynamic measures.

After the EQS, it is the second Mercedes-EQ to be based on the modular architecture for large electric vehicles. The electric saloon therefore shares many aerodynamic measures with its big brother - and is thus in the slipstream of the current aerodynamics world champion for series models. The Purpose design with a smooth underbody and mostly closed radiator shutter were a good starting point for flow optimisation, although the EQE with shorter front and rear overhangs and standard steel suspension is at a slight conceptual disadvantage.

Mercedes also offers 19 and 20-inch aero-wheels which have been optimised in the wind-tunnel. Among them is a two-tone light-alloy wheel with an almost fully closed surface but visible high-sheen rim flange.

Behind the very good aerodynamic performance is a lot of detail work. The non-visible details in particular, for example on the underbody, were developed particularly intensively. Several thousand computational runs were performed in the virtual wind tunnel alone. Below are some details of the aero development:

  • Aerodynamically favourable dimensional concept and tyres with optimised geometry
  • Aerodynamically optimised wheels
  • Cooling air control system with innovative transverse louvre makes extremely efficient use of the available installation space
  • Continuous seals in the front area, e.g. between service flap, Black Panel and headlamps
  • Streamlined design of the A-pillar
  • Wheel spoilers at front and rear
  • Elaborately harmonised underbody panelling in the rear axle area to take even greater advantage of the smooth underbody of the battery
  • Distinctive spoiler lip on the boot lid.

Extensive sealing and insulation measures reduce wind noise

In an electric car without the usual level of powertrain noise, wind noise is particularly noticeable by the occupants. That's why the aeroacoustic behaviour is particularly important. In this area too, the new EQE is one of the very best vehicles in its class.

Lots of fine-tuning in the details: in order to reduce or prevent low-frequency noises that can be perceived as reducing comfort, numerous cavities in the car body were filled with acoustically effective foam, for example.

It was also possible to reduce he high-frequency components of the wind noise in the EQE through improved seals on the door handles, the window supports and the outside mirrors. The aeroacousticians paid special attention to the seals of the transitions between the six side windows. This concept is new to Mercedes-Benz vehicles and was first used in the EQS. Another contribution is made by the A-pillar with a specially shaped trim element at the transition to the windscreen. In its development, both modern flow simulations and external noise measurements by means of a special microphone array in the wind tunnel were used. The A‑pillar designed in this way not only improves the aeroacoustics, but is also important for a low cd figure and in keeping the windows free of dirt.

The Acoustic Comfort Package further enhances noise comfort. This includes acoustically effective laminated glass on the front side windows and additional insulation in the interior. On the panoramic roof, various wind deflectors, covers and seals with improved geometry ensure high noise comfort despite the large roof opening.

[1] EQS 450+ (WLTP: combined power consumption: 19.8-15.7 kWh/100 km; CO2 emissions: 0 g/km) with 19-inch AMG wheel/tyre combination and AMG Line exterior in the SPORT drive program. The electrical consumption has been determined on the basis of Commission Regulation (EU) No. 2017/1151 according to WLTP.

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