How does sprayed engine oil lubricate cylinder walls and pistons?

In a gasoline engine, the lubrication of cylinder walls and pistons is achieved through the controlled release of oil from the engine's internal components. As oil is delivered under pressure to the crankshaft and camshaft main bearings, it naturally leaks from these bearings.1

This leaking oil is then sprayed onto the cylinder walls and cams, and directed upward into the pistons to lubricate the piston pins. By interposing a film between these rubbing parts, the oil reduces friction and wear, while also assisting in cooling the components. To manage this process, the piston rings located on the outer surface of the pistons play a critical role: while upper rings provide a seal against combustion gases, the lower rings are specifically vented to distribute and limit the amount of lubricant present on the cylinder wall.123