The exhaust system is not simply about emitting exhaust gas, but also relates to the engine's power smoothness, environmental protection, noise and other issues. The exhaust system starts with the exhaust valve inside the cylinder: after the cylinder completes the compression and explosion stroke, it uses the force of the explosion to push the piston back downwards, and the camshaft also opens the exhaust valve. Under the siphon principle effect, the exhaust gas inside the combustion chamber is naturally sucked out and discharged into the atmosphere along the exhaust head, middle, and tail sections.

The head section is the first stage of engine exhaust gas. This part needs to withstand very high exhaust temperature, up to a maximum of more than 1000 degrees. Therefore, the material and pipe diameter thickness are very important. Due to the interference of exhaust pulse, some high-performance vehicles or modified products will use the same length head section design. All racing cars are like this, so you won't see the head section directly winding into the middle section exhaust pipe, but rather curved like Fried Dough Twists, going east and west, in order to ensure that the exhaust gas from each cylinder can be discharged into the middle section within the same time difference.

The most important parts include the catalyst and oxygen sensor, which also undertake the first stage of noise reduction task. However, the most important part is still the catalyst part responsible for environmental protection work, and some vehicles' oxygen sensors are set in the first stage. At the same time, the mid section exhaust pipe also needs to consider the actual needs of the vehicle body and exterior design, and separate the exhaust path. And began to change the exhaust pipe diameter in response to vehicle positioning and engine orientation.