According to the different silencing principles and structures, car muffler can be divided into three types: resistive silencer, resistive silencer and impedance compound silencer.

1. Resistant silencer means that when various silencing units, such as expansion chamber and resonance chamber, are formed according to pipes, partitions and other components inside, reflection and interference will occur during the propagation of sound waves, thus reducing acoustic energy for silencing purposes. Anti-silencer has a limited silencing frequency, which generally has good silencing effect in low and medium frequency bands, but poor silencing effect in high frequency. Anti-silencer is often used in trucks.

2. The resistive muffler E is a muffler that fills sound-absorbing materials around the piping for internal exhaust and absorbs acoustic energy to achieve the purpose of silencing. Medium-high frequency has good silencing effect, which is seldom used as automobile exhaust muffler, and is usually used in combination with resistant muffler.

3. Impedance compound muffler is a muffler composed of resistance muffler unit and sound absorbing material, which has the common characteristics of resistance muffler and resistance muffler. It has good silencing effect on low, medium and high frequency noise.