Environmental Engineering Reference
In-Depth Information
taBle 25.8
correlation coefficient among dynamic
Injection timing, Percentage of unsaturation,
and density
correlation
coefficient
x
variable
y
variable
Percentage of
unsaturation
Dynamic injection
timing (CA bTDC)
0.935
Density
0.909
15
y
= 0.052
x
+ 9.553
r
2
= 0.875
14
13
12
11
40
50
60
70
80
90
100
% of unsaturation
FIGure 25.9
Variation of dynamic injection timing with percentage of unsaturation.
8
y
= 0.03
x
+ 4.30
r
2
= 0.677
7
6
5
40
50
60
70
80
90
100
% of unsaturation
FIGure 25.10
Variation of ignition delay with percentage of unsaturation.
The positive correlation indicates that the dynamic injection advances with increase in percent-
age of unsaturation. It can also be proposed that a unit increase in percentage of unsaturation can
advance the dynamic injection timing by 0.052° CA.
25.4.2.2 Ignition delay
The ignition delay can be defined as the time (in seconds or degrees crank angle) interval between the
points at which the fuel jet actually enters into the combustion chamber and the start of combustion.
