Fiat Bravo Service Manual page 151

Engine
Fuel system
10.
The management strategies must not only control the moment of ignition and intake air temperature/-
pressure at various engine speeds in order to allow the engine to work properly as environmental param-
eters change, but also control and manage injection in order to maintain an optimal stoichiometric ratio
(air/fuel) at all times.
System management strategies are essentially as follows:
-signal management;
-injection management;
-Fiat C O D E ignition lock function management);
-ignition management;
-engine idle control;
-fuel vapour recirculation management;
-test management
-heating/ventilation system management
SIGNAL MANAGEMENT
Upon starting, the ECU identifies injection and ignition timing, because these parameters are essential to
ensure subsequent successful implementation of all strategies.
Timing is identified by interpreting a series of signals from an rpm sensor located on the crankshaft pul-
ley and a timing sensor located on the camshaft pulley, intake side.
NOTE The term "signal framework" denotes the set of signals produced by a sensor on the crankshaft and a sen-
sor on the camshaft. Because these are located in specific reciprocal positions, they provide the ECU with
a synchronised sequence of signals that the ECU is able to identify.
The signal framework is produced as follows:
- phonic wheel on the crankshaft pulley, equipped with (60-2) 58 teeth and an angular gap of 18°
(equivalent to two missing teeth) for T D C recognition.
- wheel on camshaft pulley, intake side, comprises two long slots and one short slot, with width and ar-
rangement designed to provide the signal indicated in the figure.
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1. Cylinder TDC
2. Crankshaft angles
3. Crankshaft phonic wheel signal (rpm sensor)
4. Camshaft wheel signal (engine timing sensor)
NOTE Numbers allocated to signals indicate crankshaft angles ahead of subsequent TDC.
2
180°
Bravo-Brava
360°
.n/icdlian
@t
16v
540'
mi. bUb b/U