The purpose of the filter

The oil filter is located in the engine lubrication system. Its upstream is the oil pump, and its downstream are the various components in the engine that need lubrication. Its function is to filter out harmful impurities in the engine oil from the oil pan, and supply clean engine oil to the crankshaft, connecting rod, camshaft, turbocharger, piston rings and other moving pairs, playing a role in lubrication, cooling and cleaning, thereby extending the service life of these components. Engine oil filters are classified by structure into replaceable type, spin-on type and centrifugal type. According to the layout in the system, it can be divided into full-flow type and split type. The filter materials used in oil filters include filter paper, felt, metal mesh, nonwoven fabric, etc.
Before the 1980s, the oil filters used in domestic engines were mostly replaceable. This type of filter structure places the filter element and other components, such as springs and sealing rings, inside a metal casing, and connects and fixes the casing, filter element, etc. to a metal filter base through a pull rod. Its advantage is that the usage cost is low, and only regular maintenance and replacement of the filter element are required. The drawback lies in the excessive number of sealing points. During maintenance and replacement of the filter element, some parts may be missed, which can easily lead to leaks and is also troublesome to replace.
Since the early 1980s, when Bengbu Filter General Factory was the first in China to introduce a spin-on filter production line from Italy, spin-on filters have gradually been recognized and adopted by domestic Oems. The feature of this type of filter is that it is equipped with a check valve and a bypass valve inside, and there is only one sealing point. It can be replaced as a whole, which greatly improves the sealing performance and is easy to replace. The filter element material is mostly imported filter paper, so it has a high filtration efficiency, low flow resistance and long service life. At present, all domestic sedans adopt this type of oil filter structure. The vast majority of mini cars, large, medium and small-sized buses, light and medium-sized trucks, as well as some heavy-duty trucks and agricultural vehicles all use spin-on oil filters.