piston ring
Noun: A piston ring is a split metal ring that fits into a groove on the outer diameter of a piston in an internal combustion engine or similar machine. Its primary function is to seal the gap (or clearance) between the piston and the cylinder wall. This seal prevents combustion gases from leaking past the piston into the crankcase (blow-by) and controls the amount of oil entering the combustion chamber from below.
Piston rings are critical components in engines. They are installed in the grooves on a piston. * The mechanic replaced the worn piston rings to stop the engine from burning oil. * A broken piston ring can cause a significant loss of engine compression and power. * Proper piston ring seal is essential for efficient engine operation.
- Ring gap: The small gap at the split ends of the piston ring when it is installed in the cylinder. This gap is carefully measured and set during engine assembly to allow for thermal expansion.
- Ring land: The area on the piston between the grooves where the piston rings sit.
- Ring set: A complete set of piston rings (typically including compression rings and oil control rings) for one piston.
- Compression ring: A type of piston ring, typically the top one or two rings, whose main job is to seal combustion pressure.
- Oil control ring (or oil ring): A type of piston ring, usually the bottom ring, designed to scrape excess oil off the cylinder wall and return it to the oil pan.
- Piston: The cylindrical engine component that moves up and down within the cylinder; piston rings are fitted to it.
- Cylinder liner (or cylinder sleeve): The cylindrical surface in the engine block that the piston and piston rings move against.
- Seal (in this specific mechanical context)
- Piston seal
- To install piston rings: The act of fitting the rings onto a piston.
- Piston ring groove: The channel on the piston where the ring sits.
- Piston ring compressor: A specialized tool used to compress the rings so the piston can be inserted into the cylinder bore.
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seal consisting of a split metal ring that seals the gap between a piston and the cylinder wall
