WinGD X92DF - Pressure - Volume Diagram and Schematic of the Two-Stroke Diesel Cycle

3.1.1 Cycle of a two-stroke DF engine in diesel mode
The sequences of a two-stroke DF engine in diesel mode are as follows (refer to Figure 3-1):
•
Sequence 1 - 2
The piston moves up and thus compresses the scavenge air. This increases the
temperature of the air above the self-ignition temperature of the fuel.
•
Sequence 2 - 3
At almost TDC fuel at very high pressure is injected into the hot air in the combustion
chamber. The fuel ignites and combustion starts.
•
Sequence 3 - 4
The gases expand and push the piston down. The pressure in the combustion chamber
decreases.
•
Sequence 4 - 1
The scavenge air replaces the exhaust gas as follows:
○
At (4) the exhaust valve opens.
○
At (a) the scavenge ports get uncovered. Scavenge air enters the cylinder and
pushes the exhaust gas into the exhaust gas manifold.
○
At (b) the scavenge ports get covered.
○
At (1) the exhaust valve closes.
The cycle is completed and starts again.
Fig 3-1 Pressure - volume diagram and schematic of the two-stroke diesel cycle
1
1
2
2
3
3
4
4
a
b
V
p
00120
X92DF
AA00-0000-00AAA-020B-A
Operation Manual Short description of the DF engine
Winterthur Gas & Diesel Ltd.
- 65 - Issue 002 2020-08