The main function of the muffler is to reduce the exhaust noise of the engine and enable the high-temperature exhaust gas to be discharged safely and effectively. As a part of the exhaust pipe, the muffler should ensure that the exhaust is smooth, the resistance is small and the strength is sufficient. The muffler must withstand high-temperature exhaust from 500℃ to 700℃ to ensure that it will not be damaged or lose the noise reduction effect within the specified mileage of the car.
Automobile noise mainly comes from automobile exhaust noise. If no silencer is added, the noise can reach more than 100 decibels. Followed by engine noise and tire noise, engine noise can reach more than 90 decibels when the car is running normally, and tire noise can reach about 95 decibels when the vehicle speed is above 90 km/h. Therefore, adding a muffler to the exhaust system can reduce the exhaust noise of the car by 20-30 decibels. In terms of engines, replacing diesel engines with gasoline engines can reduce engine noise by 6-8 dB.
To measure the quality of the muffler, mainly consider the following three aspects:
1. The noise reduction performance of the muffler; (the amount of noise reduction and spectrum characteristics)
2. Aerodynamic performance of muffler; (pressure loss, etc.)
3. Structural performance of muffler. (Size, price, life, etc.)
4. The muffler frequency characteristics of the muffler. The anti-spray resistance type muffler is superior to the noise of each frequency.
5. The applicable wind speed of the muffler is generally 6-8m/s, the highest should not exceed 12m/s, and pay attention to the pressure loss of the muffler.
6. Pay attention to the cross-sectional area of the net channel of the muffler. When the air duct is connected to the muffler, if necessary (when the wind speed is limited), it needs to be amplified.
7. The installation of muffler and other muffler equipment must have independent load-bearing boom or base; it must be connected to the sound source equipment through a soft joint.
8. When two muffler elbows are used in series, the connection distance between the two elbows should be greater than 2.5 times the diagonal length of the elbow section.
9. For high-temperature, high-humidity, oil mist, and water vapor environment systems, generally use microporous structure noise reduction equipment. For clean environment systems such as operating rooms, recording studios, and clean workshops,Microporous structure noise reduction equipment should be used.