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Marine diesel engine / July 26, 2021

2-stroke & 4-stroke Engine comparison

2-Stroke Engine cycle in comparison to 4-stroke Engine: 2-Stroke Engine 4-Stroke Engine 2 strokes to complete 1 working cycle 4 strokes to complete 1 working cycle Air intake through scavenge ports Air intake through suction valves Low Speed Engines High Speed Engines Higher power Lesser power Expensive parts Cheaper parts Advantages of 2-stroke Engines in […]

2-Stroke Engine cycle in comparison to 4-stroke Engine:

2-Stroke Engine4-Stroke Engine
2 strokes to complete 1 working cycle4 strokes to complete 1 working cycle
Air intake through scavenge portsAir intake through suction valves
Low Speed EnginesHigh Speed Engines
Higher powerLesser power
Expensive partsCheaper parts

Advantages of 2-stroke Engines in comparison to 4-stroke engines:

Two-stroke engines do not have suction valves, hence simple construction.
Two-stroke engines have a high power-to-weight ratio (because the engine has twice as many combustions per second as a four stroke engine revolving at the same speed).
Two-stroke engines have the potential for about twice the power in the same size because there are twice as many power strokes per revolution.
Two-stroke engines are lighter, and cost less to manufacture.

Disadvantages of 2-Stroke Engines in comparison to 4-stroke engines:

Two-stroke engines don’t live as long as four-stroke engines as its parts wears out faster due to the lack of a lubrication system.
Two-stroke engines require a mix of oil with the gas to lubricate the crankshaft, connecting rod and cylinder walls.
Two-stroke oil can be expensive.
Two-stroke engines do not use fuel efficiently.
Two-stroke engines produce more pollution.