"Swept volume" is defined as the volume of fluid through which a piston or plunger moves when it makes a stroke in an engine, according to Oxford Dictionaries. The swept volume times the number of cylinders in an engine is known as the displacement, usually measured in liters. Calculating the swept volume is done by multiplying pi times the radius squared times the height of the chamber.
The swept volume in cars affects how much air the engine can move and the engine's performance. The compression ratio of cylinders is calculated with the swept volume as a comparison to the compression chamber volume. Cylinder volumes are often limited by the rules in various classes of racing.
In microfluidics, the swept volume is the amount of fluid directly in the flow pathway of fluidic circuit. Fluids go through this volume as they go through fittings. Internal volumes should be kept as small as possible in these circuits.
Microfluidics can have swept volumes at the molecular level. These types of systems also have what is called dead volume, or the portion of the internal volume that is out of the flow path. The dead volume is often perpendicular to the swept volume. Tubes and seals should be should fully tightened to prevent fluid leaks.