Nissan’s sound-absorbing “acoustic metamaterial”, one of the best inventions of the year?

One of the peculiarities of new automobiles, especially electrics, is that they always make less noise. Gone are the ultra noisy engines whose thunder we compared with those of Formula 1. But while all manufacturers seem obsessed with the noise emitted by the car, Nissan, the Japanese manufacturer, is trying to silence … the interior of the car. interior.

To improve motorist comfort by providing a calm and silent atmosphere. For this, she intends to rely on an invention: a new acoustic metamaterial. An innovation recognized by Popular Science as one of the 100 greatest inventions of 2020 in the “Best of What’s New Award”. Explanations.

A metamaterial to reduce nuisance for the driver

The noise inside the car is mainly caused by the combustion of the engine. Automotive engineers refer to this unwanted noise as “vibration and harshness”. Builders around the world have been trying to reduce it for decades. Especially on luxury models where a quiet and comfortable cabin is often associated with the overall quality of the vehicle. This inconvenience is also seen when it disappears, especially when equipping an electric vehicle.

It was in this race for innovation that Nissan created a special metamaterial, lightweight sound insulation. It is designed using a trellis structure and plastic film designed to control air vibration. This makes it possible to limit the transmission of noise in the frequency range from 500 to 1200 hertz. Which usually represents the range of noise that is emitted by an engine. The first vehicle to benefit from this acoustic metamaterial is the Ariya concept SUV, which was unveiled earlier this year at CES.

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Most of the insulating materials for this frequency band on the market are rubberized or fiber panels which add weight to the vehicle. Nissan’s acoustic metamaterial is only a quarter of the weight of traditional soundproofing. For, according to the Japanese company, an equivalent result in terms of soundproofing.

Tomorrow, silence for all drivers?

Nissan wants to make the widest range of vehicles possible for its innovation. To democratize high-end soundproofing? That’s what Susumu Miura, the group’s materials engineer, says. “We plan to use acoustic metamaterial in a wide range of applications – not only in luxury cars and electric vehicles, but also in vehicles where the use of heavy sound insulation materials has been limited.” It is because the competition in this area is increased.

A frantic race of manufacturers to silence

Nissan isn’t the only automaker that strives to reduce interior noise. A real frantic race, not an automobile, but in innovation. Tesla tackled the problem for the Model 3, the company’s first consumer electric car. After its launch in July 2017, the vehicle was criticized for excessive wind and road noise. The manufacturer then mobilized all its teams to make significant improvements in the field. Third-party companies have even taken to marketing sound reduction kits for the Model 3. Kits that include sheets of material that fit directly into the wheel arch or trunk.

Fans will certainly be watching the Ariya concept SUV, the first vehicle on which the metamaterial will be deployed. While waiting for its democratization? For Popular Science, there is no doubt.