Management Of The Injection - Fiat Bravo/Brava Workshop Manual

Engine
Fuel system
Bravo-Brava W
16v
1999 update
10.
M A N A G E M E N T OF THE INJECTION
The injection management strategies are designed to provide the engnie with the correct quantity of fuel
at the desired time according to the engine operating conditions.
NOTE The presence of the flow meter allows the direct measurement of the mass of air drawn in, mak­
ing the presence of the intake air temperature sensor superfluous.
The management of the injection basically consists of calculating the injection time, determining the in­
jection phase and the subsequent implementation via the operation of the injector.
The "basic" injection time depends on the specifications of the injector and corresponds to the quantity of
fuel to be injected into each cylinder. The latter is, in turn, determined by multiplying the quantity of air
drawn in by each cylinder (calculated on the basis of the quantity of intake air and the engine rotation
speed) for the desired mixture strength in relation to the engine operating point.
The final injection time is determined by means of a calculation algorhythm in which the "basic" time is
corrected by a series of coefficients which take into account the different engine operating conditions
which are highlighted by the various sensors present in the system.
A: "basic" injection time
B: correction coefficient:
low engine temperature
high engine temperature
starting and post-starting
butterfly fully open
deceleration
acceleration
feed-back mixture control
self-adjustment
cut-off
intermediate injection time
extra-pulse
non phased injection management
6
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