23.2.2022BMW i7 undergoes acoustic testing to remove all sounds
The BMW i7 is apparently being developed with the aim of combining hallmark driving pleasure with a level of comfort that is in a class of its own.
One of the goals in the series development of the electric BMW i7 is to keep as much disturbing noise away from the occupants as possible. BMW has now provided some details about the corresponding test programme on acoustic test benches specially designed for electromobility.
A key factor is the acoustic properties. The level of wellbeing in the interior of the pure-electric luxury sedan is largely determined by the degree to which disturbing noises can be kept away from the occupants. There are a variety of potential noise sources to be taken into account here, so near-production prototypes of the BMW i7 – and indeed all other model variants of the future BMW 7 Series – are undergoing an extensive programme as part of their acoustic testing.
At the Research and Innovation Centre (FIZ) in Munich, test and development engineers are checking the full range of the vehicle’s sound emissions and immissions. Motor and rolling noise are analysed in detail, as are the aeroacoustics and vibration comfort, in order to fully determine the acoustic properties of the new luxury sedans.
This also includes precise alignment of acoustic pedestrian protection and the motor sound emitted in the interior of the BMW i7 – the latter having been developed as part of BMW IconicSounds Electric, a collaborative venture between the BMW Group and Hollywood film music composer Hans Zimmer.
The driver of the BMW i7 has a choice: characteristic silence or BMW IconicSounds Electric developed in collaboration with Hans Zimmer.
The acoustic test benches at the new branch of the BMW Group’s Research and Innovation Centre FIZ North are specially designed to meet the requirements of electromobility and enable all driving situations to be simulated realistically.
Here, any irritating noises registered by development engineers during test drives on the road can be recreated and selectively eliminated. Roller dynamometers with a unique quiescent level and interchangeable surface coverings enable the measurement and validation of drive acoustics and tyre noise on all road surfaces that are relevant to day-to-day traffic anywhere in the world.
In order to be able to test the effectiveness of all measures under extreme climatic conditions too, the development engineers at FIZ North use an acoustic climate test bench specially designed for this purpose. Here, all globally relevant conditions can be simulated and a wide variety of noise sources can be analysed and optimised such as the acoustics of the air conditioning and ventilation system throughout the entire vehicle – in particular at very low or very high temperatures.
In the same way as the motor and tyre rolling acoustics, ambient noise can also be selectively reduced. For this purpose, the aeroacoustics of the BMW i7 are perfected in the acoustic wind tunnel. Clear-cut body surfaces, flush-integrated door handles, aerodynamically optimised exterior mirrors and an almost completely closed underbody not only contribute to the low air resistance of the luxury sedan, they also help create its excellent acoustics.