Carbon Filter And Fuel Vapour Cut-Off - Fiat Bravo Service Manual

Bravo-Brava
FUEL PRESSURE REGULATOR (RPM 40)
This differential diaphragm device is set to a pressure of 3.00 ± 0.05 bar in the factory.
Pressurised fuel from the pump exercises thrust on reflux valve (7) countered by calibrated spring (8).
When pressure setting is exceeded, reflux valve opens and excess fuel returns to the tank in order to sta-
bilise pressure in the circuit. The vacuum in the intake manifold (acting also on injector nozzle ) acts on
regulator diaphragm through intake (9) in order to reduce the load on the calibration spring.
The pressure differential between the fuel and the injector's surroundings (intake manifold) is therefore
maintained constant under all engine service conditions. The injector flow (for a given supply voltage)
thus depends solely on injection time established by the E C U .
NOTE 77?e ECU assumes pressure as a fixed parameter. The regulator should never therefore be tam-
pered with; otherwise the mixture concentration specified for the engine will be altered.
Copyright Fiat Auto
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P4A43CJ02
CARBON FILTER AND FUEL VAPOUR
CUT-OFF VALVE
These components form part of the fuel evap-
oration control and vapour recovery system.
They are located in the right wheel arch com-
partment and can be reached by removing
the rear part of the right front wheel arch
compartment trim.
1. Fuel vapour cut-off solenoid
2. Carbon filter
Carbon filter
This consists of carbon granules (4) that trap fuel
vapour entering intake (5).
Warm flushing air enters intake (1), through paper
filter (3) and flows over the carbon granules to re-
move fuel vapours and carry them toward the outlet
(2) and then on toward the cut-off valve.
Air entering through intake (5) may also be pulled
back by a vacuum in the tank, when it serves to ven-
tilate the tank. Partition (6) ensures that the flush-
ing air flows over all the carbon granules and pro-
motes the release of fuel vapour toward the inlet
manifold.
Two springs (7) allow the mass of granules to ex-
pand when the pressure increases.
Engine
Fuel system
10.
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