Muffler is an important function of automobile noise reduction. It is generally divided into three categories: resistance (shape), resistance (shape) and composite. The silencing effect of different materials is also different.

The resistive automobile muffler is mainly composed of porous pipe and sound-absorbing fiber (cotton absorption). The sound absorption coefficient of the latter material changes with physical properties such as density and diameter, that is, the larger the fiber density, the smaller the diameter, and the higher the sound absorption coefficient. At the same time, the influence on the silencing effect is also related to the overall silencing effect. Of course, there are many factors affecting the silencing effect, such as section perimeter, effective length and section area. The larger the perimeter and effective length, the better the silencing effect.

1、 How does the exhaust gas of resistive car muffler work?

The resistive muffler is composed of porous pipe and sound-absorbing fiber. When the waste gas contacts with the fiber through the porous pipe, it generates vibration, generates heat energy due to friction and bonding, and the noise is transformed in this process, so it is also called sound-absorbing process.

The resistance muffler has the characteristics of small volume, so the middle drum of most original vehicles prefer to use the resistance shape. If you want to give full play to its silencing function, the installation position is generally close to the direction of the engine. Many experimental results show that the suppression effect of resistive muffler on medium and high frequency noise of engine is better than that of medium frequency and medium frequency. Similarly, the performance of anti exhaust is just opposite to that of resistance.

Classification of automobile Silencers

2、 Composite (shape) silencer.

As its name indicates, the structure of the composite automobile muffler integrates the characteristics of the first two silencers, that is, there are cotton suction and expansion chamber at the same time. As mentioned above, the two silencers have the length and length of each other in the corresponding engine speed, and the composite can well balance the two characteristics, and has a large volume and volume, but the cost is relatively high.

Classification of automobile Silencers

3、 Resistant silencer

There is no sound-absorbing cotton in this structure, also known as reflective muffler, which is mainly composed of diaphragm and expansion chamber. An ordinary automobile muffler has three expansion chambers of different sizes. The exhaust is reflected in these cavities and interferes with each other (friction) to achieve the silencing effect. The cavity with large cavity is more conducive to deal with the noise, but its size is also limited by the chassis shape. SUVs such as Audi Q7 and BMW X5 have this advantage. In addition, due to different ways of use, the volume specific resistance of the resistant muffler is large, so it is also mostly installed at the tail. For the characteristics of obvious suppression effect of medium and low frequency noise, it has won the praise of many original manufacturers.

The quality of the muffler directly affects the driving experience. The better the silencing effect, the better the silencing effect of the car.