But the growth of its electric lineup, and the imminent launch of the first electric M-car, doesn't mean it has forgotten about the gas ones. In a patent recently found by CarBuzz, the company has a new intake manifold designed to give you more real noise in your gas-powered car.
Make More Real Engine Sounds
The way the company describes it, the desire is to create "a particularly advantageous noise behavior." It does that by linking the engine intake to the cabin, letting the engine transmit its actual noise directly to the driver and passengers.
It works by creating an intake manifold with two different intake paths. The main one is designed to work like most modern intakes. That is, it quiets down the noise because most drivers don't want to hear that loud rush of air as the engine breathes at part throttle. If you've ever driven a new Tacoma with the factory snorkel, you understand that the sounds can get old in a hurry, especially in traffic.
The second intake channel is made without the baffles and re-directs that cut down on noise. The air going through that one can make its full noise. BMW's engineers installed a valve that can block the second channel. That way, when you (or when BMW) don't want the extra noise, the loud path is blocked off. When you do want the noise, then it can open up to let the intake sounds fill the cabin and, presumably, excite the driver.
All of that work is just to create more noise from the engine's intake. You'll be able to hear it quite well from outside of the car, but BMW says it will still be dampened inside by the car's firewall. It doesn't want that to happen.
Sounds Transmitted Inside Using A Familiar Method
Getting the sound into the cabin uses an older and more common invention called a sound generator. BMW has been using that device for years already. It works by connecting the intake to the firewall using a tube that runs between them. There is foam in the tube to limit the amount of sound, and the actual intake air is separated from the duct so that you aren't pulling the air from the cabin into the engine.
BMW is far from the only automaker to use a device like a sound generator. Mazda uses a sound tube on the MX-5 Miata, and has even changed it with model refreshes to tweak the sound. Volkswagen has used noise pipes over the years, but also uses a unique method called the Soundaktor. The Soundaktor attaches a speaker driver to the firewall to turn the entire firewall into a speaker to transmit engine sounds. Other automakers use sound tube methods or completely artificial noises from the speakers.
The advantage of this new BMW invention is that it gives you real engine intake sounds, not speaker-generated noises. But it also lets you quiet the car down, so that you're not whooshing and roaring when you're just putting around town. Combined with an active exhaust valve, it has the potential to give your BMW a little more verve in M-mode. You know, in case the suspension and power aren't giving you enough.
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