What is the main purpose of piston rings in an engine?

The main purpose of piston rings in an engine is to contain combustion pressure. Piston rings fit snugly around the piston and create a seal between the piston and the cylinder wall. This sealing is crucial because it prevents the escape of combustion gases from the combustion chamber into the crankcase, ensuring that the engine operates efficiently and maintains performance. By containing the pressure created during combustion, piston rings help maintain the necessary compression for the engine to function optimally.

In addition to this primary role, piston rings also serve secondary functions such as controlling oil consumption and helping to facilitate heat transfer from the piston to the cylinder wall. However, their most critical function is the containment of combustion pressure, which is essential for the engine's overall efficiency and power output.