role
　　Oil filter in the lubrication system in order to make the lubrication system oil flow unimpeded, to avoid impurities scratch, brushed parts surface, oil in the friction surface, must be strictly filtered. In order to achieve a satisfactory filtering effect without increasing the oil resistance, the coarse filter is usually connected in series with the main oil channel, and the fine filter is connected in parallel with the main oil channel.
　　1, float type oil collection filter, in order to make the oil pump work well, it is necessary to remove the large particles of impurities in the oil before entering the oil pump, this task is undertaken by the collection filter. It is connected to the oil inlet of the oil pump. When the oil pump works, the oil is inhaled from the slit between the cover and the float. After filtering out the coarse impurities through the filter net, the oil pipe welded on the float enters the oil pump. When the filter screen is silted up, the suction force of the inlet pipe increases to overcome the strength of the filter screen and make the bad mouth leave the cover. Then the oil enters the suction pipe directly from the ring mouth without going through the filter screen.
　　2, the coarse filter in series between the oil pump and the main oil channel, so it is also called the full flow filter, used to remove larger impurities in the oil. It is mainly composed of upper cover, outer shell, paper filter element and bypass valve. When the engine is working, the lubricating oil with pressure is sent into the cavity around the filter element and the larger impurities in the oil are blocked by the paper filter element, while the clean lubricating oil enters the inner cavity of the filter element and then enters the main oil channel of the cylinder body through the oil outlet.
　　3, fine filter: its role is to filter out smaller impurities in the lubricating oil, usually parallel with the main oil channel, there are centrifugal and board type two.
　　4. Structure of centrifugal fine filter: the hollow shaft is fixed on the shell, and the rotor body and end sleeve are connected together. It is located on the thrust bearing and can rotate freely around the rotor shaft. The compression nut fastens the rotor cover to the rotor body, and the upper part is pressed by spring to restrict the axial movement of the rotor. Under the rotor, there are two nozzles which are opposite to each other. When the engine is running, a small part of the engine oil is pumped from the oil pump into the filter through the oil port. When the oil pressure is lower than 9s kpa, the inlet pressure limit valve is closed, and the fine filter does not work. When the oil pressure exceeds 98 kpa, the pressure limit valve gradually opens, the oil through the central hole of the rotor shaft, from the oil hole. Then through the oil hole into the rotor body, and ejected from the two nozzles, so the jet reaction force is to push the hand rotation. When the oil pressure rises to 294 kpa, the rotor speed can reach more than 5000r/min. The proportion of impurities in the lubricating oil in the inner cavity of the rotor is larger than that of the lubricating oil. Under the action of rotating centrifugal force, the impurities are thrown to the rotor wall and covered on the wall. Clean lubricating oil at the center, from the center into the two nozzles, constantly spray outwards, ejected lubricating oil flow back to the lower crankcase.
　　This paper is organized by dongguan oneness filtration technology co., LTD.