What is a car muffler?
What is a car muffler?
The car muffler is used to reduce the motor vehicle engine working noise parts, because the length difference between the two pipes is equal to half of the wavelength of the sound wave issued by the car, so that the two sound waves in the superposition of interference offset each other and weaken the sound intensity so that the sound is reduced, so as to play the effect of muffling.
The working principle of car muffler
Automobile exhaust noise is the main component of driving noise. All countries in the world have strict regulations on the limits of the noise of various vehicles, exhaust muffler is such a device to reduce exhaust noise.
The function of an exhaust muffler is to eliminate noise by reducing and attenuating the pulsation of exhaust pressure.
According to the principle of interference, the exhaust muffler has absorption and reflection. Absorption mufflers reduce the energy of waste gas by rubbing it against sound-absorbing materials such as glass fiber, steel fiber and asbestos; Reflective muffler has a number of the series harmonic cavity and different length of porous reflection tube connected together, exhaust gas in which through many times of reflection, collision, expansion, cooling and reduce its pressure, reduce vibration and energy.
Under the actual situation, the automobile is the more comprehensive use of different muffler principle combinations to design the exhaust muffler, at the same time in the comfort of the small passenger car will also use a plurality of muffler units for multi-level muffler noise reduction control.
Structure classification of car muffler
According to the principle and structure of car muffler, automobile muffler can be divided into resistance muffler, resistance muffler and impedance compound muffler
1. Resistant silencer
A resistance muffler is composed of the expansion chamber, resonance chamber and other muffler units through internal pipes, partitions and other components, the sound wave in the propagation of reflection and interference, reduces the sound energy to achieve the purpose of the muffler. The resistant muffler is limited in a frequency band, and usually has a good muffler effect in low and middle-frequency band, but a poor muffler effect in the high-frequency band.
2. Resistance muffler
A resistive muffler is a muffler that absorbs sound energy by filling sound-absorbing material around the pipe through which the internal exhaust passes. It has a good sound attenuation effect on middle and high frequency and is seldom used as an automobile exhaust muffler. It is usually combined with a resistant muffler.
3. Impedance compound muffler
The impedance composite muffler is composed of a resistance muffler unit and sound-absorbing material, which has the common characteristics of resistance and resistance muffler. It has a good muffling effect on low, medium and high frequency noise.
The role of a car muffler
Reduce engine exhaust noise, and make high-temperature exhaust gas can be safely and efficiently discharged. As a part of the exhaust pipe, the muffler should ensure its exhaust is smooth, has small resistance and has sufficient strength. Muffler to withstand 500℃~700℃ high-temperature exhaust, to ensure that in the specified mileage of the car, no damage, do not lose the muffler effect.