Etude de la combustion de gaz de synthèse issus d'un processus de ...

Experimental set ups and diagnostics
Piston position (mm)
500
400
300
200
100
Compression-Expansion
Single compression
0
90 95 100 105 110 115 120 125 130 135 140
Time (ms)
Figure 3.12 – Piston displacement during one and two strokes without combustion.
tel-00623090, version 1 - 13 Sep 2011
The difference on the figure 3.12 is around 2.0 ms in the initial, which indicates that the
RCM cam of the compression-expansion strokes is shorter than the compression one.
The corresponding in-cylinder volume versus time is lower for the compressionexpansion
case, which corresponds to higher in-cylinder pressures.
In an ideal spark-ignited internal combustion engine one can distingue three stages:
compression, combustion and expansion. The entire pressure rise during combustion
takes place at constant volume at TDC. However in an actual engine this does not
happen as well as in the RCM. The pressure variation due to combustion in a
compression and expansion rapid compression machine is shown in figure 3.13, where
three stages of combustion can be distinguished.
70
12.5 ms BTDC
C
60
Motoring
Pressure (bar)
50
40
30
20
B
A
10
D
0
90 100 110 120 130 140 150 160 170 180
Time (ms)
Figure 3.13 – Stages of combustion in a RCM.
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