Fiat Bravo Service Manual page 362

Bravo-Brava
98 range
1. Pressure rod
2. Pin
3. Jet
4. Coil
5. Valve
6. Shutter w i t h ball
7. Control area
8. Supply volume
9. Control volume
10. Fuel outlet connector (low pressure)
1 1 . Control manifold
12. Supply manifold
13. Electrical connection
14. Fuel inlet connector (high pressure)
15. Spring
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P4A13KJ01
I N J E C T O R S
The injectors, fitted on the cylinder head, are t h e
electro-magnetic type, operated directly by the
injection control unit.
The injectors are equipped w i t h a high pressure
supply duct and a recirculation pipe at ambient
pressure; the supply duct is connected to the
supply manifold (rail) w i t h pipes designed t o
withstand the high operating pressures.
The injector can be divided into t w o parts:
- actuator/nozzle consisting of a pressure rod
( 1 ) , pin (2) and jet (3);
- solenoid valve consisting of a coil (4) and
valve ( 5 ) .
Operation
The operation of the injectors can be divided i n -
to three stages:
1. rest position
The coil (4) is de-energized and the shutter ( 6 )
is in the closed position and does not allow the
introduction of fuel into the cylinder:
where Fc is the force produced by the pressure
w h i c h acts on the control area (7) of the pres-
sure rod (1) and Fa is the force produced by the
pressure acting on the supply volume ( 8 ) .
2. start of injection
The coil (4) is enerigzed and raises the shutter
( 6 ) . The fuel flows from the control volume (9)
to the return manifold causing a decrease in
pressure in the control area ( 7 ) . A t the same
time, the line pressure through the supply m a n i -
fold (12) exerts a force F a > F c on the supply
volume (8) raising the pin (2) w i t h the conse-
quent introduction of fuel into the cylinders.
3. end of injection
The coil (4) is de-energized and returns the
shutter (6) to the closed position w h i c h restores
a balance w h i c h returns the pin (2) to the
closed position and consequently the injection
ends.
E n g i n e
Fuel system
10.
F o F a
13