1.INTAKE: (Suck)

–Begins at top dead center

–The piston descends from the top of the cylinder to the bottom of the cylinder, increasing the volume of the cylinder

–A mixture of fuel and air is forced in by the atmosphere (This is called normally aspirated)

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2.COMPRESSION: (Squeeze)

–Both intake and exhaust valves closed, the piston moves toward the top of the cylinder compressing the air or fuel-air mixture into the cylinder head

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3.POWER: (Bang)

–While the piston is close to top dead center, the compressed air–fuel mixture in a gasoline engine is ignited, (spark plug) in gasoline engines

–The resulting pressure from the combustion of the compressed fuel-air mixture forces the piston back down toward bottom dead center

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4.EXHAUST: (Blow)

–The piston once again returns to top dead center while the exhaust valve is open

–This action expels the spent fuel-air mixture through the exhaust valve(s)