A piston ring is a split ring that fits into a piston groove in a reciprocating engine such as an internal combustion engine.
The three main functions of piston rings in reciprocating engines are:
Piston rings are small and relatively inexpensive parts working in a complex and very expensive engine. Unless the piston ring is functioning perfectly, the engine will lose efficiency with consequential reduction in power and increased fuel consumption.
Piston rings have a wide range of industrial applications. Regardless of whether they are used in aircraft, locomotive, car or a compressor they are responsible for the performance of the system in which they are used.