The lubricating oil (lubricant) supply system in the engine. It is used to supply lubricating oil to the friction surfaces of bearings and gears for cooling and lubrication, preventing corrosion of parts and removing impurities.
The lubrication system consists of an oil pump, an oil filter, a nozzle, an oil-air separator and a radiator. The oil pump includes a gear pump to increase the lubricating oil and an oil return pump to collect the oil. There is a lot of air in the oil return, so the total flow of the oil return pump is several times that of the auxiliary pump.
The oil filter is used to remove impurities, usually in a mesh format. The oil filter in the booster oil circuit is equipped with a bypass valve, which can guarantee the normal supply of oil when the oil filter is blocked or starts at low temperature.
Sometimes a magnetic plug type chip detector is installed in front of the oil return pump to detect wear failure when collecting metal fragments in the oil. The nozzle is direct flow type and the high speed bearing can supply oil from the bearing inner ring.
Oil and gas separators usually have a high-speed rotating impeller that separates the oil and gas by centrifugal force. Air is light and can be drawn from the rotor cavity to the top of the oil tank. There is also a static on-board oil and gas separator. The radiator is a device that uses fuel or air to cool the lubricating oil.
The lubricating oil system is divided into two types: closed type and open type. In the closed lubrication system, all the lubricating oil after heat dissipation returns to the oil tank and can continue to be cooled. In some lubrication systems, irradiated oil flows directly into the inlet of the auxiliary pump without returning to the oil tank.
In the open lubrication system, all used lubricating oil is discharged out of the machine, and the oil return pump and other accessories can be omitted, but it increases fuel consumption, which is suitable for engines that run for a short time. period of time.
The working medium used in the lubrication system is lubricant, and the lubricating oil used in aircraft engines is also called lubricating oil. There are two types of lubricating oil: mineral oil and synthetic oil (see lubricating materials).