The function and working principle of different types of oil filters

The oil filter plays a vital role in the engine. It can effectively filter out metal wear debris, mechanical impurities and oxides in the oil. Once these impurities enter the lubrication system, they will aggravate the wear of engine components and may even cause blockage of oil pipes or oil passages.

First of all, the filter collector is introduced. It usually adopts a filter screen design and is installed before the oil pump to prevent large particles of impurities from entering the oil pump. Filter is divided into floating and fixed two. The floating filter can absorb cleaner oil on the oil surface, but the foam on the oil surface is also easily sucked in, which affects the oil pressure and makes the lubrication effect less stable. The fixed filter collector is installed below the oil level. Although the cleanliness of the sucked oil is slightly inferior to that of the floating type, it can avoid foam inhalation, provide stable and reliable lubrication effect, and has a simple structure. It has become the first choice for automobile engines.

Next is the full-flow oil filter, which is connected in series between the oil pump and the main oil passage to ensure that all oil is filtered through it. At present, most automobile engines use full-flow oil filters. This kind of filter has a wide variety of filter elements, among which paper filter elements are widely used because of their high efficiency filtration performance. The paper filter element oil filter is divided into two types: decomposable and integral structures, which have the characteristics of easy replacement and overall replacement respectively. In addition, the full-flow oil filter is also equipped with a bypass valve. When the filter element is severely blocked by impurities, the oil pressure rises. After reaching a certain pressure value, the bypass valve opens, allowing unfiltered oil to directly enter the main oil passage. To ensure the normal operation of the lubrication system.

For large trucks, especially heavy trucks, the engine usually adopts a combination of full-flow and split-flow oil filter layout. The full-flow filter is mainly responsible for filtering impurities with a particle diameter of more than 0.05mm, while the split-flow filter further filters out tiny impurities with a particle diameter of more than 0.001mm, and only handles 5% to 10% of the oil supply of the oil pump. The split flow fine filter is divided into two types: filtration type and centrifugal type, in which the centrifugal oil fine filter is widely used because of its high efficiency centrifugal separation technology. This type of filter is equipped with a rotor, which is supported on the shaft through a rolling bearing, and the working pressure of the lubrication system itself is used to push the rotor to rotate at a high speed, so that solid impurities are separated under the action of centrifugal force and accumulated on the inner wall of the rotor.

Finally, the centrifugal oil filter is introduced, which is characterized by stable performance, reliable structure and no need to replace the filter element. Only need to disassemble the rotor regularly and clean up the accumulated stains to reuse, and the service life is long. However, its disadvantages are also obvious, including complex structure, high price and heavy weight, and at the same time, it has higher requirements for the technical level of maintenance personnel.