FAA Aviation Mechanic Powerplant (AMP)Reciprocating EnginesEasy
What is the primary function of the oil control rings on a reciprocating engine piston?
- ATo prevent combustion gases from escaping past the piston.
- BTo provide a seal for cylinder compression during the power stroke.
- CTo transfer heat from the piston to the cylinder walls.
- DTo scrape excess oil from the cylinder walls and return it to the crankcase.
Show answer & explanationAnswer & explanation
Correct answer: D. To scrape excess oil from the cylinder walls and return it to the crankcase.
Oil control rings are specifically designed to manage the lubrication of the cylinder walls, scraping off excess oil on the downstroke and allowing a thin film for lubrication on the upstroke, returning the scraped oil to the crankcase.
Why the other options are wrong
- A. This is the primary function of compression rings.
- B. This is the primary function of compression rings.
- C. While rings do transfer some heat, this is not their primary function; the piston crown and skirt are more involved.
Oil Control Ring
A piston ring designed to regulate the amount of oil on the cylinder wall, ensuring adequate lubrication while preventing excessive oil consumption.
- Located below the compression rings.
- Scrapes oil from cylinder walls.
- Returns oil to the crankcase via slots/holes.
Memory trick: Compression seals power, Oil controls lubrication.