Editing Engine displacement (section)

==Definition==
The overall displacement for a typical reciprocating piston engine is calculated by multiplying together three values; the distance travelled by the piston (the [[Stroke (engine)#Stroke length|stroke length]]), the [[Area of a circle|circular area]] of the cylinder, and the number of cylinders in the whole engine.<ref>{{cite web |title=Math for Automotives - Displacement of a Piston |url=https://www.avc.edu/sites/default/files/studentservices/lc/math/piston_displacement.pdf |website=arc.edu |publisher=Antelope Valley College |access-date=18 August 2021}}</ref>

The formula is:

:<math> \text{Displacement} = \text{stroke length} \times \pi \left(\frac{\text{bore}}{2}\right)^2 \times \text{number of cylinders}</math>

Using this formula for non-typical types of engine, such as the [[Wankel engine|Wankel design]] and the oval-piston type used in [[Honda NR]] motorcycles, can sometimes yield misleading results when attempting to compare engines. Manufacturers and regulators may develop and use specialised formulae to determine a comparative nominal displacement for variant engine types.