Engine displacement

Description

Engine displacement is the volume swept by all the pistons inside the cylinders of a reciprocating engine in a single movement from top dead centre (TDC) to bottom dead centre (BDC). It is commonly specified in cubic centimetres (cc or cm3), litres (l), or (mainly in North America) cubic inches. Engine displacement does not include the total volume of the combustion chamber. Engine displacement is determined from the bore and stroke of an engine’s cylinders. The bore is the diameter of the circular chambers cut into the cylinder block. Stroke is the reciprocating motion, used in reciprocating engines and other mechanisms, is back-and-forth motion. Each cycle of reciprocation consists of two opposite motions: there is a motion in one direction, and then a motion back in the opposite direction. Each of these is called a stroke. The term is also used to mean the length of the stroke.

Related formulas

Variables

VdEngine displacement (in3)
πpi
bThe bore ( the diameter of the circular chambers cut into the cylinder block) (in)
strThe length of the stroke (in)
NThe number of cylinders (dimensionless)