Differences between two-stroke and four-stroke engines
Differences between two-stroke and four-stroke engines
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Two-stroke and four-stroke engines are both types of internal combustion engines, but they differ significantly in their operational mechanisms, efficiency, and applications.
Operational Mechanisms
Two-Stroke Engines:
Cycle Completion: A two-stroke engine completes a power cycle in just two strokes of the piston (one up and one down) and one revolution of the crankshaft.
Strokes: The two strokes are:
Compression and Ignition: The piston moves up, compressing the air-fuel mixture. The spark plug ignites the mixture, causing an explosion that pushes the piston down.
Exhaust and Intake: As the piston moves down, it uncovers the exhaust port, allowing exhaust gases to escape. Simultaneously, the intake port opens, allowing fresh air-fuel mixture to enter the cylinder.
Valves: Two-stroke engines do not have valves; instead, they use ports (intake and exhaust ports) controlled by the piston's movement.
Four-Stroke Engines:
Cycle Completion: A four-stroke engine completes a power cycle in four strokes of the piston (two up and two down) and two revolutions of the crankshaft.
Strokes: The four strokes are:
Intake Stroke: The piston moves down, creating a vacuum that draws air-fuel mixture into the cylinder through an open intake valve.
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