The engine has three filters

The engine has three filters of air, oil and fuel, and the air conditioning filter in the car is generally called "four filters".  They are responsible for the intermediate filtration of engine intake system, lubrication system, combustion system and cooling system respectively.  

A. The oil filter is located in the engine lubrication system.  Its upstream is the oil pump, downstream is the engine to lubricate the various parts.  Its role is to filter harmful impurities from the oil pan, to clean oil supply crankshaft, connecting rod, camshaft, supercharger, piston ring and other motion pair, play the role of lubrication, cooling, cleaning, so as to extend the life of these parts.  

B, fuel filter has carburetor and electronic injection type, the use of carburetor gasoline engine, fuel filter is located in the import side of the oil pump, the working pressure is small, generally using nylon shell, electronic injection engine fuel filter is located in the export side of the oil pump, the working pressure is high, usually using metal shell.  

C, the automobile air filter is located in the engine intake system, it is composed of one or several clean air filter components assembly.  Its main function is to filter out harmful impurities in the air that will enter the cylinder to reduce the early wear of the cylinder, piston, piston ring, valve and valve seat.  

D. Automobile air conditioning filter is used to filter the air inside the car compartment and the air circulation inside and outside the car.  Remove the air in the carriage or into the air in the carriage of dust, impurities, smoke odor, pollen, etc., to ensure the health of passengers and remove the odor in the carriage, at the same time, the air conditioning filter also has the role of making the windshield is not easy to atomize.