
Different Oil filters (primary oil filter and secondary filter) are installed in the modern engine for the oil clean and defending friction surfaces from mechanical impurities. Motor oil properties are deteriorating during operation of the engine: results viscosity and oiliness reduction. Oil contaminate with solid mechanical impurities of carbon and metal particles, which appear as a result of engine parts wearing. In addition motor oil is polluted resins and oxidation products.
Oil filters are divided on full flow filter and non-full flow filter.

Oil filters: a – full-flow filter; b – centrifuge; 1 – plug; 2 – drain pipe; 3 – housing of oil filter; 4 – oil pressure gauge; 5- spring of overflow valve; 6 – overflow valve; 7 – spring; 8 – bolt; 9 – filter element seal; 10 – cap; 11 – oil pipe line; 12 – filter element; 13 – oil pressure reduction sensor; 14 – mounting plane; 15 – finger nut; 16 – casing; 17 – strainer; 18 – rotor axis; 19 – cap of rotor; 20 and 21 – gaskets; 22 – rotor housing; 23 – centrifuge housing; 24 – fuel-jet; 25 – thrust ball bearing; 26 – steel reflector; K – reaction force.
Full-flow filter is oil filter through which all oil passes. It is installed in series in a lubrication system.
Non-full flow filter is oil filter through which 10-15% oil passes.
It is installed in parallel in the lubrication system.
Primary oil filter provides cleaning of engine from
large mechanical impurities and tarry deposits.
Secondary oil filter. As replaceable filtering elements, tape paper and cardboard bags or other materials are used in which the oil is filtered by seeping through the micro pores of the element.
Oil filter Construction and How an oil filter works
Oil filter consists of housing 3, drain pipe 2, filtering element 12, spring 7 and cap 10, which mounted on the housing by bolt. Drain pipe welded to the bolt 8. The pump pumps oil through the oil pipe to the filter element.
Then the oil enters the cylinder block through the channel in the mounting plane 14.
The resistance of a clean filter corresponds to a pressure drop of approximately 10-20 kPa. An overflow valve 6 with a spring 5 is installed in the drain pipe. It works and bypasses the not cleaning oil into the cylinder block when the filter element is clogged. An oil pressure gauge 4 in the system is screwed into the filter housing, and an emergency oil pressure reduction sensor 13 is screwed into the bottom of the housing. The plug 1 serves to remove sludge from the filter housing.