HOW TO CHOOSE THE RIGHT MUFFLER？
The exhaust pipe of a car is the main reason for driving noise. Countries around the world have strict regulations on the noise limits of various vehicles. The exhaust muffler is such a device for reducing exhaust noise.
1.Exhaust Muffler
The function of the exhaust muffler is to eliminate noise by reducing and attenuating the pulsation of the exhaust pressure. According to the principle of interference, the exhaust muffler has two basic modes of absorption and reflection. The shock absorbers reduces its energy by friction of the exhaust gas on sound absorbing materials such as the glass fiber, the steel fiber and asbestos. The reflective spoiler has a plurality of series-connected harmonic chambers connected with different lengths of porous reflection tubes, and the exhaust gas undergoes multiple reflections, collisions, expansions and cooling to reduce the pressure and reduce vibration and energy.
In actual situations, most of the cars use a combination of different muffling principles to design the exhaust muffler. At the same time, in the small passenger car with high comfort requirements, they also use multiple muffler units for noise reduction.
2.Dimensions and Type of Exhaust Silencer
According to the principle and structure of noise elimination, automobile muffler can be divided into three types: resistance muffler, resistive muffler and impedance composite muffler.
The first category is the resistant muffler. The resistant muffler is composed of pipes, partitions and other components to form various muffling units such as expansion chambers and resonance chambers. When sound waves are reflected and interfered during propagation, the sound energy is reduced so that it can achieve the purpose of sound elimination. The resistant muffler has a limited frequency band. Generally, the muffling effect of the low frequency band and the middle frequency band is good, the effect of high frequency noise cancellation is poor, and the truck uses a resistant muffler.
The second type is a resistive muffler. The resistance muffler is for filling the sound absorbing material around the pipe through which the internal exhaust gas passes to absorb the sound energy for the purpose of sound elimination. It has a good sound absorption effect on medium and high frequency and is usually used in combination with a resistant muffler.
The third type is an impedance composite type muffler. The impedance composite muffler is a muffler composed of a combination of a resistive muffling unit and a sound absorbing material. It has good sound absorption for low, medium and high frequency noise.
3.Structural Material of Exhaust Muffler
Automotive mufflers are commonly available in two materials: 304 and 409 stainless steel. The muffler made of 304 stainless steel is more resistant to corrosion and high temperature. The muffler made of 409 stainless steel is easy to rust but has poor corrosion resistance.
