Saab 9000 - Page 50

Fuel injection
(contd.) .
Point adaptation
RPM
900
1260
1640
1830
2020
2400
2780
3160
3540
.
..
1• .. ,.
•
,
.......
1aa u,
2020
u,
0
... ....
11N .... ·-
.....
-.. o.•
o.n
me
Ut ,,..
._. OM UI
- ...
IOIO . OIF
....
1120
1.00
1.03
If the engine control module calculates the fuel injec-
tion duration as 8 ms but the closed loop adjusts it to
9 ms because the car's fuel pressure is somewhat
low, the engine control module will "learn" the new
fuel injection time. It accomplishes this by changing
the correction factor for the relevant engine speed
and load point in the main fuel matrix so that the re-
sult will be a fuel injection time of 9 ms. In this exam-
ple, the new correction factor will be 0.90 x 9/8
=
1.01
(see Fig. above).
Point adaptation can change the points in the main
fuel matrix by
±
25% provided that the closed loop is
activated, the temperature of the coolant is above
64°C (147°F) and the EVAP canister purge valve is
not in operation.
KPa
96
0.80
0.78
0.82
0.81
0.81
0.84
0.84
0.86
0.88
Saab9000
Technical Description 47
I
112
0.80
0.81
0.82
0.82
0.83
0.86
0.86
1.01
0.92