Now, as soon as white drivers feel that their cars have poor sound insulation, they immediately think of installing sound-absorbing cotton. In addition, many media articles also measure the sound insulation level of a car by disassembling the car and using the number of sound-absorbing cotton.

Automobile sound insulation is a systematic project. If it's that simple, it's too easy to make money for auto engineers.

For example, Volkswagen has always been soundproof, but if you open the hood of some Volkswagen cars such as golf, you will find that there is no sound-absorbing cotton in the hood. However, this independent brand is much more "kind", but the reality is that Volkswagen is still good without soundproof cotton.

So, where is the secret of car sound insulation? This time, we take an American 7-seat medium and large SUV as an example to see how mainstream car manufacturers do mute projects.

Improve car body rigidity

Suppression of vehicle body vibration is the most important thing in NVH engineering, because the excellent rigidity of vehicle body can improve torsional and bending modes, achieve excellent vibration and noise suppression ability, and eliminate vehicle body vibration to the greatest extent.

High rigidity not only contributes to safety, but also improves NVH.

This needs to be optimized by upgrading the structure and materials at design time. For example, the jeep commander at the same level we tested also benefited from the super-rigid body sound insulation level. Volkswagen's excellent sound insulation effect also benefits from the high rigidity of the new MQB platform.

This time we used it as the technical analysis of Buick Angkewei, and the proportion of high-strength steel in the whole vehicle reached 84%. High rigidity can not only meet the strength and safety requirements of the whole vehicle, but also greatly reduce the weight of the whole vehicle.

Opportunities to reduce noise emissions

Do everything possible to reduce the chance of noise emission, which is also a good way to "treat the symptoms". Noise mainly comes from wind noise, road noise of chassis, vibration noise of engine and other mechanical parts.

Intelligent resistance reduction grid

In addition, BMW 7 Series began to use intelligent drag reduction grille in its early years, which can certainly improve the intake efficiency of the engine. In terms of reducing wind resistance, Buick Angkor's intelligent drag reduction grille adopts a series of aerodynamic designs, such as the unfolded inverted L-shaped functional air curtain design, aerodynamic exterior rearview mirrors, and even the underbody spoiler and the tail integrated duck tail spoiler.

In fact, we interviewed engineers such as our own brand Roewe. They also considered the bottom turbulence of high-end models, and the aerodynamic performance is also conducive to reducing noise.

Sound-absorbing cotton hand, blocking noise

Finally, talking about sound-absorbing cotton. Admittedly, sound-absorbing cotton is one of the effective methods to reduce noise, but it is emphasized that it is one of them.

Acoustically coated soundproof carpet (front row)

In this respect, the design of each family is different. It can't be said that the same level is necessarily good, and it can't be said that Buick is definitely better than Volkswagen. Here, we just take Angke Banner as an example to list some automobile sound-absorbing cotton.

Angkewei uses 2500 g/m2 light dissipative material on the inner side of the front wall, and 2mm high polymer sound insulation polymer and 25 mm foaming material on the outer side to block engine noise in all directions. The side front wall soundproof pad and brake pedal soundproof pad also contain engine noise and front tire noise.

5 mm sound insulation laminated windshield

It should be reminded that an important task to reduce noise is to improve the sealing of the car. One of the reasons why some Japanese cars, including Honda, are not as good as their own brands is poor sealing.

We saw at the scene that Angkewei's body filling process includes 34 kinds of expansive filling materials and three door sealing strips, which effectively reduces the leakage of the whole vehicle and achieves the air tightness of BBA luxury car. Finally, the advanced acoustic laminated windshield and the front door side window with a thickness of 5mm bring excellent wind noise performance.

Active noise reduction

Many years ago, ANC was a very high-tech technology, and now even Honda's new generation of Lingpai cars have adopted ANC. However, I would like to remind you that ANC technology itself has high and low points. For example, most cars use only one microphone to collect data, which is definitely different from luxury cars using multiple microphones.

The new generation ANC active noise reduction system in Angora Banner consists of three parts: ANC processor, speaker and MIC microphone, in which the core ANC processor can be used according to the driving conditions of vehicles.

ANC microphone in the front row

The low-frequency noise of the engine at 40- 180Hz is captured by four microphones located on the top lining, and the canceling sound wave with the opposite phase to the actual noise is accurately released through the speaker through a special algorithm, thus reducing the second-order and fourth-order noise of the engine and reducing the roar of the engine.

Automobile sound insulation is a systematic project.

Numerous old drivers who look at cars know that although American cars have various problems, they have to be convinced of one advantage-generally, American cars have good sound insulation, and coupled with soft suspension, the luxury and comfort of traffic are first-class.

However, automobile sound insulation is a systematic project, including body rigidity, sealing and aerodynamics, which are all basic designs and cannot be improved by later modification. Therefore, it is too natural to use the number of sound-absorbing cotton to determine the sound insulation level of vehicles.

This article comes from car home, the author of the car manufacturer, and does not represent car home's position.