In an internal combustion engine, what describes the total piston displacement?

In an internal combustion engine, what describes the total piston displacement?

• A. The total volume inside the engine crankcase at rest.
• B. The volume displaced by all the pistons during one revolution of the crankshaft.
• C. The sum of volumes of all cylinders at BDC.
• D. The volume of the combustion chamber.

Answer: (B)

Piston displacement is the swept volume the pistons move through as they travel in their cylinders. It’s the total amount of air-fuel charge that can be moved by all pistons during one engine cycle, calculated by summing each cylinder’s bore area times its stroke. For a four-stroke engine, that cycle spans two crankshaft revolutions, and the displacement equals the combined swept volumes of all cylinders. The description that best matches this idea is the volume displaced by all the pistons during one revolution of the crankshaft, since it captures the concept of swept, movable volume across all cylinders. The other options describe static spaces or the volume at a single position, which do not reflect how much volume is swept by the pistons during operation.

Piston displacement is the swept volume the pistons move through as they travel in their cylinders. It’s the total amount of air-fuel charge that can be moved by all pistons during one engine cycle, calculated by summing each cylinder’s bore area times its stroke. For a four-stroke engine, that cycle spans two crankshaft revolutions, and the displacement equals the combined swept volumes of all cylinders.

The description that best matches this idea is the volume displaced by all the pistons during one revolution of the crankshaft, since it captures the concept of swept, movable volume across all cylinders. The other options describe static spaces or the volume at a single position, which do not reflect how much volume is swept by the pistons during operation.