Definition:NVH refers to noise, vibration, and harshness. Because the above three occur simultaneously and are inseparable in mechanical vibration such as automobiles, they are often put together for research. Roughness refers to the quality of noise and vibration. It describes the human body’s subjective perception of vibration and noise and cannot be directly measured by objective measurement methods.

In general, the harshness description is the feeling of extreme fatigue caused by vibration and noise. Simply put, all the tactile and auditory sensations of the occupants in the car belong to the scope of the research on the characteristics of the car's NVH. In addition, it also includes the strength and life of auto parts due to vibration.

Types of noise: The noise in the car mainly comes from five aspects: engine noise, wind noise, body resonance, suspension noise and tire noise.

When a vehicle is running, the engine runs at high speed, and its noise is transmitted into the vehicle through firewalls, chassis, etc.; the resonance of the vehicle body generated by the car driving on bumpy roads, or the resonance of the window opened when driving at high speed will become noise. Due to the narrow space in the car, noise cannot be effectively absorbed, and collisions sometimes cause resonance in the car.

During driving, the noise generated by the suspension system of the car and the noise generated by the tires will be transmitted into the car through the chassis. Different suspension methods, different tire brands, different tire patterns, and different tire pressures produce different noises; different body shapes and different driving speeds cause different wind noise levels. Under normal circumstances, the higher the driving speed, the greater the wind noise; due to design reasons, the car drag coefficient cannot be changed, and it is difficult to completely and effectively reduce the wind noise.
How to reduce the noise in the car

To reduce the noise in the car, we must first find the sound source, and find out the path and mode of sound transmission, and then reduce the amount of sound transmission, thereby reducing the noise in the car. For example, wind noise is mainly transmitted through the body. The solution is The key parts of the car body are filled with sound-proof foam, which blocks the sound transmission path and achieves the purpose of reducing wind noise

Blocking the path of sound transmission or absorbing the energy of sound is mainly achieved by some parts of the interior and exterior decoration, such as: Door Trim Interior Acoustic Insulation, Headliner Acoustic Insulation, A-B-C Pillar Acoustic Insulation, Center Console Acoustic Insulaiton, Instrument Panel Acoustic Insulation, Wheel House Liner Acoustic Insulation, Quarter Trim Acoustic Insulation, Fender Liner Acoustic Insulaiton, Engine Acoustic Insulation, Trunk Trim Acoustic Insulation. Wenzhou Chinese Fiber Co.,Ltd product of CICsorb^TM Automotive Acoustic Insulaiton material definition and design of interior and exterior parts have a great influence on the NVH performance of the vehicle.

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