A 2-stroke engine in ships is a powerful internal combustion engine that completes a power cycle in two strokes of the piston. Key engine parts include the cylinder, piston, crankshaft, connecting rod, scavenge ports, exhaust valve, and fuel injectors. It is widely used in marine propulsion due to its high efficiency and compact design.

Key specifications and technical properties of a 2-stroke engine in ships:

Engine Size: Bore: 200mm–1,000mm, Stroke: 1,000mm–3,000mm, Displacement: 1,000–100,000 cm³ per cylinder.

Grade: Marine diesel oil (MDO) or heavy fuel oil (HFO) with sulfur content ≤0.5% (IMO 2020 compliant).

Viscosity: 180–700 cSt at 50°C for HFO, 2–15 cSt at 40°C for MDO.

Buoyancy: Not applicable to engine parts; primarily relevant for hull design.

Material: Cylinder liners: Cast iron with chromium plating; Pistons: Aluminum alloy or forged steel; Connecting rods: Forged steel; Crankshaft: High-tensile forged steel; Bearings: White metal (Babbitt) or bronze.

Lubrication: Cylinder oil viscosity: 70–150 BN (Base Number) for acid neutralization.

Cooling: Freshwater or seawater cooling with corrosion-resistant materials (e.g., cupronickel for heat exchangers).

Power Output: 1,000–100,000 kW per engine, depending on configuration.

Compression Ratio: 14:1 to 18:1 for efficient combustion.

Exhaust System: Turbochargers with wastegate or variable geometry for scavenging.