The fourth stroke of a four-stroke cycle where the piston moves upward from bottom dead center to top dead center and pushes the burned exhaust gases out of the cylinder.

One of the four 180-degree full "sweeps" of the piston moving in the cylinder of a four-stroke, internal-combustion engine (originally devised by Nikolaus Otto in 1876). During the exhaust stroke, the piston moves from BDC to TDC and forces exhaust gases from the cylinder into the exhaust system. Note: The 180-degree duration of the exhaust stroke is commonly shorter than the period during which the exhaust valve is open, sometimes referred to as the true "Exhaust Cycle." The exhaust stroke is followed by the intake stroke.

Phase of the four-stroke cycle when waste gases are pushed out the exhaust valve.