One of the goals of the development of the all-electric BMW i7 series was to keep passengers as possible away from disturbing noises. BMW now offers some detailed information about the corresponding test procedures on acoustic test benches designed specifically for electric vehicles.
For customers who can afford a premium car, they need more than just a car, but also driving comfort, space and materials, including workmanship, and the acoustic comfort of the car. For quiet electric vehicles, acoustic characteristics are even more important. But the drivers in the i7 shouldn't be muted either: like the i4 and iX, for example, the i7 has what Hollywood composer Hans Zimmer called iconicSounds.
BMW said the comfort inside the pure electric limousine depends largely on the noise control of the i7, which BMW claims to keep i7 passengers away from disturbing noise. The German automaker says a large number of possible noise sources must be considered. As part of the acoustic tests at the Munich Research and Innovation Center (FIZ), the BMW i7 near-production prototypes were correspondingly extensive.
In the new FIZ Project House North, acoustic test benches are set up specifically for this purpose, designed to meet the requirements of electric vehicles. According to BMW, the roller test bench has a "unique level of quietness" and replaceable lining to simulate and measure rolling noise "on all roads associated with daily traffic worldwide." The stated goal was to reproduce and specifically eliminate those disturbing noises that development engineers noticed during road test drives.
Other features were not organized on the test bench, but were taken into account in the design. For example, the drive units are acoustically optimized, the electric motor is mounted for the i7, and special noise encapsulation is developed. In addition, the increased body stiffness in the front-end area helps to improve vibration performance. Like the iX, tires are equipped with foam absorbers to eliminate noise inside the tires.
The i7 prototype, which is close to production, has been put into road testing. In order to maintain the promotion of the series, BMW has released some information about test drives in recent hot-land tests and winter test drives. Only when the i7 goes to market will customers truly feel the acoustic comfort. BMW plans to show it this year alongside the other models of the 7 series.
While the acoustic test bench was purchased for the i7 to score on high-end competitive models with the Mercedes EQS or tesla Model S Refresh with active noise cancellation, other electric BMW models will also be able to benefit from this facility in the future.