Motorcycle exhaust pipe principle
Automotive engine exhaust system has two main functions, one is to burn after the high temperature of the exhaust gas to the car or the vehicle side to avoid the impact of the occupants of the car; Second, the use of "silencer" will be high temperature and high pressure emissions The noise generated during the process is reduced to an allowable limit.
The first exhaust emissions process is the first encounter exhaust manifold, exhaust manifold in the design of the most important thing is to avoid the exhaust between the cylinder interference, so that exhaust gas as far as possible completely discharged from the tube, the exhaust pipe The role of the middle itself is relatively simple, as long as the exhaust from the exhaust manifold to the exhaust tail pipe, and some exhaust system in the middle will be more than an expansion chamber to reduce the exhaust pressure; because the engine internal high temperature and When the high-pressure exhaust gas enters the exhaust manifold, the pressure is still high, and at this time due to contact with the exhaust manifold pipe wall will have a shock wave, the frequency of occurrence can reach thousands of times per minute, each time will issue a very high frequency Annoying noise, so the need for good treatment, when the exhaust gas through the exhaust manifold, the shock wave from the supersonic down to the speed of sound or even lower than the speed of sound, but this time the noise emitted by the shock wave is still large, even after the middle of the tube The road is not enough to reduce its power, so in the middle and the end of the section to install the "expansion room" and "silencer" to offset its power, and some exhaust pipe design only tail section of a silencer, and some will The addition of an expansion chamber, silencer, and expansion chamber in the middle is similar in appearance, with the difference that there are multiple partitions or porous passages inside the muffler to absorb sound waves and reduce the flow rate, while the expansion chamber is simply a large hollow container , Its purpose is also very simple to expand the exhaust gas to reduce the pressure, so more than one expansion chamber design will reduce the noise a lot.
The exhaust system is from the exhaust port connected to the combustion chamber, through the exhaust manifold (ie, the head section), the middle of the exhaust pipe (including the catalyst section), to the exhaust pipe tail section, is the entire exhaust emission process.
