Ans: Engine displacement is the total swept volume of the pistons inside the cylinders of an engine. It is calculated from the diameter of the cylinders, the distance the piston travels, and the number of cylinders. Displacement is a significant factor because it has a direct impact on the output power of the engine, fuel efficiency, etc.In simple words, is a determining factor in the horsepower and torque that an engine produces; also, much fuel an engine consumes. The equation for calculating displacement is given by:Engine displacement = π/4 * bore² * stroke * the number of cylinders. Displacement of the engine is usually measured in litres (L), or cubic centimetres (cc), or cubic inches (CI).