Actual PV Diagrams Of 4 stroke And 2 stroke Marine Diesel Engines

              The pressure-volume (PV) diagram is drawn by measuring the pressure inside the cylinder, and plotting its value against the angle of the crankshaft, over a complete engine cycle 
Actual PV Diagram Of 4 Stroke IC Engines

1:-    Inlet valves open
1-2:- Suction stroke
2:-     Inlet valve closes
2-3:- Compression stroke
3:-     Injection begins
4:-    Injection ends
4-5:- Expansion stroke
5:-    Exhaust valve opens
5-6:- Exhaust stroke

6:- Exhaust Valve Close

Actual PV Diagram Of 2 Stroke Marine Diesel Engines

0:-     Scavenge ports open
0-1:- Air sucked in and pushes out the left over exhaust gas
1:-    Piston at BDC
1-2:- Completion of scavenging and filling of fresh air
2:-    Scavenge ports close
2-3:- Compression stroke
3:-    Exhaust valve close
3-4:- Compression stroke continues
4:-    Fuel Injection starts
5:-    Piston at TDC
6:-    Fuel Injection ends
6-7:- Expansion stroke
7:-    Exhaust valve open
7-0:- Blowdowns of exhaust gas

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