1. Overall design principles of air filters
The air filter should minimize intake resistance as much as possible under the conditions allowed by its structure. The resistance of the intake system depends on many variables, including the cross-sectional size of the inlet and outlet pipes, the structure of the air filter, the type of elbow, the type of filtering material, the effective filtering area, etc. The only way to accurately determine the system resistance is through testing based on experience.
The installation of the air filter should ensure that any sealing surface on the air filter is not deformed, and should be firmly and firmly fixed on the frame, ensuring that the air filter has no difficulty in removing the paper filter element and does not need to remove other parts.

2. Design principles for air filter components
(1) Air filter inlet and outlet pipes
The components used in the gas outlet pipeline must be thoroughly calculated. Firstly, the pipeline must not be sucked down under maximum resistance conditions, and every connection of the pipeline must be permanently sealed. Especially the pipeline between the filter and the inlet of the engine should not have any leaks or small holes, otherwise a large amount of dust will enter the engine and cause engine failure.
The air inlet must be located in a location where dust is not easily accessible; Avoid inhaling exhaust gases from the engine into the intake system; There should be no other components obstructing the air inlet. The original intake position should be as high as possible to prevent rain and snow from entering the intake system.
(2) Air filter element
The function of the filter element is to filter out larger particles in the air, such as dust and sand. Currently, there are mainly two types of materials: filter paper and sponge.
The filtering effect of filter paper is related to the diameter of micropores, and the air resistance is larger than that of commonly used filter sponges. If you want to reduce the overall air resistance, you can increase the area of the filter paper, but it has poor water resistance and cannot be reused. During the maintenance cycle, the air resistance increases linearly.
The filtration effect of sponges is poor. If you want to improve the filtration effect, you need to increase the thickness, which is proportional to the air resistance. Therefore, filter paper is more suitable for manufacturing air filters. But the sponge has good water resistance, can be reused, has low maintenance costs, and has little change in air resistance during a maintenance week.
(3) Air filter housing
For the sake of environmental protection, the exhaust gas in the crankcase and the gasoline vapor in the carburetor oil chamber need to be re fed into the cylinder for combustion. Therefore, relevant interfaces should be retained on the air filter housing.
Design drainage holes inside the air filter and consider setting drainage pipes below the installation position of the housing filter.