Noise reduction measures for the intake system
(1) Reasonably design the air filter. In general, the larger the muffler volume, the better the muffling effect, but it also requires consideration of the layout space, part weight, and part cost factors. In general, the air filter has a volume that is more than three times the engine volume, and a good noise reduction effect can be achieved.
(2) Determine the diameter and length of the air filter inlet and outlet pipes. Reducing the diameter of the air filter inlet and outlet pipes and increasing the expansion ratio will help reduce noise, but will increase the resistance of the intake system, reduce the intake air volume of the engine, and affect engine performance. The effective noise cancellation frequency of the air filter is related to the length of the intake pipe. The length of the intake pipe is increased, and the effective noise cancellation frequency of the air filter will shift to the low frequency. Therefore, it is necessary to properly design the length of the inlet and outlet pipes.
(3) Reasonably design the noise elimination component. Commonly used muffling elements include resonant cavities, quarter-wave tubes, porous tubes, and braided tubes. The resonant cavity is generally for low frequency, the 1/4 wavelength tube is generally used to eliminate medium and high frequency noise, and the porous tube and the braided tube are mainly used to eliminate relatively wide frequency band noise.