What are the functions of compression rings and oil rings?
2 Answers
Compression rings serve to seal the gap between the piston and cylinder, preventing gas leakage and oil blow-by, while transferring heat from the piston to the cylinder. Oil rings function to scrape excess lubricating oil from the cylinder walls and distribute oil evenly on the cylinder walls. Below are relevant introductions about compression rings and oil rings: 1. Compression rings: Generally, each piston in an engine is equipped with 2 to 3 compression rings. Poor sealing by compression rings can lead to various issues such as difficult engine starting, reduced power, increased fuel and oil consumption, and more. 2. Oil rings: Oil rings are divided into two types: conventional oil rings and composite oil rings. They are a type of piston ring, typically made of alloy cast iron. The middle of their outer cylindrical surface is cut with a groove, and many through oil drainage holes or slits are machined at the bottom of the groove.
Having repaired cars for over a decade, I've seen countless engines fail due to piston ring issues. The compression rings act like tiny security guards, sealing the combustion chamber to prevent high-temperature, high-pressure gases from escaping. The top compression ring bears the brunt of the work, enduring temperatures exceeding a thousand degrees. Meanwhile, the oil control ring functions like a janitor – positioned lower on the piston, its narrow slits scrape excess oil off cylinder walls back into the oil pan. If this cleaning fails, oil sneaks into the combustion chamber, causing blue smoke. Most older cars suffering from oil burning, compression loss, or power deficiency? Eighty to ninety percent of cases trace back to these two components wearing out.
