Noise reduction measures for the intake system
The methods of gas flow noise and structural noise processing are relatively simple and often not the main noise of the intake system. Here we mainly discuss the noise reduction measures of low frequency noise.
1. Reasonably design the air filter. In general, the larger the muffler volume, the better the muffling effect, but it is also necessary to comprehensively test 2. Determine the diameter and length of the air filter inlet and outlet pipe. 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 muffling 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 muffling frequency of the air filter will be shifted 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 the noise of a relatively wide frequency band.