Key points of the function of piston rings in aviation piston engines

The key points of the function of piston rings in aviation piston engines can be summarized as follows:

Sealing function

Preventing gas leakage: One of the main functions of the piston ring is to seal the gap between the piston and the cylinder wall, preventing high-pressure gas in the combustion chamber from leaking into the crankcase. This sealing effect is crucial for maintaining the normal combustion pressure and thermal efficiency of the engine. Air leakage not only reduces engine power but also increases the consumption and deterioration of engine oil.

Labyrinth seal: Piston rings are usually designed for use in combination of several rings. The openings of each ring are staggered at a certain Angle to form a "labyrinth" gas leakage channel, which extends the gas leakage path and effectively reduces the amount of gas leakage.

Lubricating effect

Storing lubricating oil film: The tiny gap between the piston rings and the cylinder wall can retain and store an appropriate amount of lubricating oil film, preventing direct contact between the piston and the cylinder wall, reducing friction and wear, and extending the engine's lifespan.

Oil scraping and oil distribution: The oil rings in the piston rings have the function of oil scraping. When the piston moves up and down, they can scrape off the excess engine oil on the cylinder wall and leave a thin oil film at the same time, ensuring the normal lubrication of the cylinder, piston and rings.

Heat conduction effect

Heat conduction: Piston rings can effectively complete the thermal movement process of transferring heat from the piston through the piston rings to the cylinder wall. The heat conducted by the piston rings accounts for a relatively large proportion of the heat received by the piston top (up to 70% to 80% in non-cooled pistons), which helps maintain the thermal balance of the piston and prevent it from overheating.

Cooling effect: The heat of the piston is conducted to the cylinder wall through the piston rings, and then the heat is carried away by the cooling system, thus playing a role in cooling the piston.

Supporting and guiding functions

Supporting the piston: The piston rings support the piston and keep it in a reasonable position within the cylinder, preventing direct contact between the piston and the cylinder wall, reducing frictional resistance, and preventing piston knocking.

Guiding function: The piston rings guide the piston, ensuring the stability of the piston's movement trajectory within the cylinder and maintaining an appropriate gap between the piston and the cylinder wall.

Control engine oil consumption

Preventing oil from flowing up: Piston rings can effectively prevent excessive oil from the cylinder wall from entering the combustion chamber, reduce oil consumption, and prevent carbon deposits caused by oil combustion from affecting heat transfer performance.

Adjusting the thickness of the oil film: Through its special design, the piston rings can not only ensure the thickness of the oil film on the cylinder wall to meet the lubrication requirements, but also prevent excessive oil from entering the combustion chamber.

Summary

The key functions of piston rings in aviation piston engines include sealing, lubrication, heat conduction, support and guidance, as well as controlling oil consumption and many other aspects. These functions jointly ensure the normal operation and stable performance of the engine, which is of great significance for maintaining the efficient and reliable operation of the engine.