What is the function of automotive piston rings?
1 Answers
Here are the specific functions of automotive piston rings: 1. Sealing: This refers to sealing the combustion gases, preventing them from leaking from the combustion chamber into the crankcase, minimizing gas leakage to improve thermal efficiency. Gas leakage not only reduces engine power but also causes engine oil to deteriorate. 2. Oil regulation (oil control): It scrapes off excess lubricating oil from the cylinder walls while ensuring a thin oil film remains on the walls, guaranteeing proper lubrication for the cylinder, piston, and rings. In modern high-speed engines, the role of piston rings in controlling the oil film is emphasized. 3. Heat conduction: Piston rings transfer heat from the piston to the cylinder liner, serving a cooling function. In non-cooled pistons, 70-80% of the heat received by the piston crown is dissipated through the piston rings to the cylinder walls, while in cooled pistons, 30-40% of the heat is dissipated this way. 4. Support: Piston rings keep the piston centered in the cylinder, preventing direct contact between the piston and cylinder walls, ensuring smooth piston movement, reducing friction resistance, and preventing piston knocking. Generally, gasoline engines use two compression rings and one oil ring, while diesel engines typically use two compression rings and one oil ring.
