Piston Displacement (PD):

\[ PD = \frac{\pi \cdot D^2 \cdot L \cdot n}{4} \]

Where:

• \(PD\) is the piston displacement in cubic centimeters (cm³).
• \(D\) is the piston diameter in centimeters (cm).
• \(L\) is the length of the stroke in centimeters (cm).
• \(n\) is the number of cylinders.