As we all know, during vehicle driving, the high-pressure combustion gas in the engine cylinder will emit 120dB noise. In order to meet the relevant requirements of vehicle exhaust noise, the vehicle muffler is a device used to reduce exhaust noise.

The main function of automobile muffler is to reduce the exhaust noise of engine and ensure that high-temperature exhaust gas can be safely and effectively discharged. According to the silencing principle and structure, it can be divided into resistance muffler, Resistance Muffler and impedance composite muffler. The silencer mainly uses silencing devices such as resonant cavity and expansion cavity composed of pipes and diaphragms of various shapes and sizes to make sound waves reflect or interfere in the resonant cavity and expansion cavity, so as to reduce sound energy. Its structure can effectively absorb medium and low frequency noise. The muffler of the utility model is appropriately arranged with sound-absorbing materials in the pipeline to partially absorb sound energy, and its structure can effectively absorb medium and high-frequency noise. Nowadays, most automotive silencers use impedance composite silencers, which have common impedance and resistance, and have good silencing effect on low-frequency and medium-frequency noise.

The silencer is mainly made of stainless steel material. It is arranged under the casing and connected with the engine. It can withstand not only high-temperature gas of 500 ℃ ~ 700 ℃, but also various complex environments. Long term use of automobile muffler equipment will lead to some phenomena:

1、 Muffler housing "discoloration"

The box is made of stainless steel plate, because the color of stainless steel plate will vary with the temperature. The fundamental reason for this phenomenon is that the stainless steel plate reacts with oxygen in the air at high temperature to form an oxide film. Due to the different thickness of the oxide film, diffraction occurs on the oxide film irradiated by natural light and presents different colors.

The test shows that when the temperature reaches 300 ℃, the stainless steel plate begins to change color, and the color changes are different with the increase of temperature, mainly yellow red dark red black blue.

Because the internal structure of the muffler is composed of multiple different cavities, the part with serious discoloration is in the intake high temperature cavity, and the part with serious discoloration is in the intake high temperature cavity. Its temperature changes greatly, and then serious discoloration occurs.

2、 The silencer surface is rusty.

After driving for a period of time, the surface of the muffler is rusted, which is caused by the selection of stainless steel materials (suh409l, SUS304, sus436l, 439m, etc.). Although it has the ability to resist atmospheric oxidation and corrosion resistance, its corrosion resistance changes with the changes of the steel's own chemical composition, service conditions and environmental media.

The exhaust pipe silencer belongs to high temperature, high humidity, stone injury, damp heat alternation and other parts. The surface of the silencer is easy to rust when the vehicle is driven in bad environment for a long time, especially in rainy and snowy weather.

Rust on the muffler surface is an objective and normal phenomenon, and the rust only occurs on the stainless steel surface and will not affect the use function of the muffler. Therefore, in the process of use, the muffler can be used normally as long as there is no rust penetration and rust leakage.

Therefore, when you use a car, you don't have to worry about the discoloration and corrosion of the muffler of the exhaust system, because this is an objective and normal phenomenon.