At present, there are two main types of air filters used in automotive engines: oil bath type and paper type.
The use of oil bath air filters has a long history. This type of air filter is directly installed on the intake pipe of the engine, with a small volume and convenient layout, and does not require a large layout space; The air filter has a long service life and can be repeatedly maintained and used, but its filtration efficiency is low and varies with engine operating conditions. It has high filtration efficiency under rated operating conditions and low filtration efficiency under partial loads. However, automotive engines often operate under partial conditions, so the actual filtration efficiency of this air filter is relatively low. In addition, this type of air filter requires cleaning with gasoline during maintenance, resulting in waste of oil and a longer maintenance time.
Paper dry air filters have been widely used in automobiles. The filter has high efficiency and is not affected by changes in engine load. Convenient maintenance, no need for gasoline cleaning, and not limited by objective conditions. The filtering efficiency has a natural growth effect, which means that with the use of time, the filtering efficiency does not decrease, but slightly improves. The filter arrangement can be installed vertically or horizontally. Indicator lights can be used to effectively control the maximum allowable value of intake resistance to ensure timely maintenance, ensure engine efficiency, and extend the service life of the engine.