DOE-HDBK-1018/1-93
Diesel Engine Fundamentals
FUNDAMENTALS OF THE DIESEL CYCLE
Fundamentals of the Diesel Cycle Summary (Cont.)
A two-stroke engine requires one rotation of the crankshaft to complete one
cycle. The events occur as follows:
Intake - the piston is near BDC and exhaust is in progress. The intake
valve or ports open and the fresh air is forced in. The exhaust valves or
ports are closed and intake continues.
Compression - after both the exhaust and intake valves or ports are closed,
the piston travels up towards TDC. The fresh air is heated by the
compression.
Fuel injection - near TDC the fuel is injected by the injectors and the fuel
starts to burn, further heating the gasses in the cylinder.
Power - the piston passes TDC and the expanding gasses force the piston
down, rotating the crankshaft.
Exhaust - as the piston approaches BDC the exhaust valves or ports open
and the exhaust gasses start to flow out of the cylinder.
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