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

Chapter 6
6.3.2.2 In-cylinder volume
The instantaneous cylinder volume is calculated based on the piston position as a
function of crank angle and fitted by polynomial functions in order to be implemented in
the code. Thus, first one evaluates the error in the polynomial approach.
Figure 6.6 shows the comparison between the experimental volume inside the cylinder
and the corresponding six degree polynomial expression applied up to top dead center
to better fitting. The remaining part is constant and equal to the clearance volume. The
maximum error is about 0.5% (5 cm 3 ).
1200
1000
Experimental
Polynomial
tel-00623090, version 1 - 13 Sep 2011
Volume (cm 3 )
800
600
400
200
0
180 210 240 270 300 330 360 390 420 450 480 510 540
Crank Angle (degrees)
Figure 6.6 – In-cylinder volume polynomial fitting: single compression downdraft syngas case,
ignition timing at 12.5 ms BTDC.
Figure 6.7 shows in-cylinder volume variation during compression and expansion and
the corresponding six degree polynomial. The maximum error is 1.5% (15 cm 3 )
obtained at TDC.
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