4-stroke Marine Diesel Engines
As the name indicates it complete one cycle in 4 stroke of the piston
4 Stroke Cycle= 4 stroke of the piston in one cycle
= 2 Complete revolution
> Suction Stroke
The stroke of the Piston begins at top dead Centre and ends at bottom dead Centre. In this stroke the Intake valve must be in the open position while the piston pulls an air fuel mixture into the cylinder by producing vacuum pressure in the cylinder through its downward motion . The piston is moving down as air is being sucked in by the download motion against the piston.
> Compression Stroke
This stroke begins at BDC, and ends at TDC. In this stroke the piston compresses the air fuel mixture in preparation for ignition during the power stroke. Both the intake and exhaust valves are closed during this stage
> Power Stroke
Also known as combustion stroke. This is the start of the second revolution of the four stroke cycle. This stroke begins at TDC, the compressed air-fuel is ignited by heat generated by high compression, forcefully returning the piston to BDC. This stroke produces mechanical work from the engine to turn the crankshaft.
> Exhaust Stroke
During the exhaust stroke, the piston returned from BDC to TDC. While this stroke exhaust valves open and all exhaust gas expels.