The oil filter is also called lube filter, or oil grid, which is located in the engine lubricating system. The upstream of the engine filter is the oil pump, and the downstream is the parts of the engine that need lubrication. The oil filter can be divided into full flow type and partial flow type. The full flow filter is connected in series between the oil pump and the main oil passage, so that all lubricating oil entering the main oil passage can be filtered. The shunt cleaner is connected in parallel with the main oil passage, and only part of the lubricating oil is sent by the filter oil pump.

Function of the oil filter
The mechanical filter filters the harmful impurities in the engine oil from the oil pan, and supplies clean engine oil to the crankshaft, connecting rod, camshaft, supercharger, piston ring and other motion pairs to lubricate, cool and clean, thus extending the life of these parts. Simply put, the role of the oil filter is to filter the oil, make the oil entering the engine cleaner, and prevent impurities from entering the engine to damage precision components.
According to the structure, the mechanical filter can be divided into replaceable type, rotary type and centrifugal type; According to the arrangement in the system, it can be divided into full flow type and split flow type. Filter materials used for mechanical filter include filter paper, felt, metal mesh, non-woven cloth, etc.

Operating principle of oil filter
During engine operation, metal wear debris, dust, carbon deposit oxidized under high temperature, colloidal sediment, water, etc. are constantly mixed with lubricating oil. The role of the oil filter is to filter out these mechanical impurities and gums, keep the lubricating oil clean and extend its service life. The oil filter shall have the characteristics of strong filtering capacity, small flow resistance, long service life, etc. Several filters with different filtering capacities are installed in general lubrication systems
The filter collector, coarse filter and fine filter are respectively connected in parallel or in series in the main oil passage. (The one in series with the main oil passage is called full flow filter, and all lubricating oil is filtered by the filter when the engine is working; the one in parallel is called split flow filter). One coarse filter is in series in the main oil passage, which is full flow type; The secondary filters are connected in parallel in the main oil passage and are of split flow type. Modern automobile engines are generally equipped with a filter collector and a full flow oil filter. The coarse filter removes impurities with a particle size of more than 0.05mm from the engine oil, while the fine filter is used to remove fine impurities with a particle size of more than 0.001 mm.