Stroke (engine)

It involves the downward movement of the piston, creating a partial vacuum that draws an air-fuel mixture (or air alone, in the case of a direct injection engine) into the combustion chamber.

In this stage, the air-fuel mixture (or air alone, in the case of a direct injection engine) is compressed to the top of the cylinder by the piston.

The combustion stroke is the third phase, where the ignited air-fuel mixture expands and pushes the piston downwards.

In this phase, the piston moves upwards, squeezing out the gasses that were created during the combustion stroke.

A Granada, Spain-based company, INNengine invented an opposed-piston engine with four pistons on either side to make a total of eight.

Engine displacement is calculated by multiplying the cross-section area of the cylinder (determined by the bore) by the stroke length.