Fiat 1995 Brava, Service Manual

Page: 472 / 544

B r a k i n g s y s t e m Bravo-Brava
Anti-lock braking system
33.
Pressure maintenance phase
P4A16A001
1. Electronic control unit 8. Rapid pressure reducing valve
2. Low-pressure accumulator (reservoir)
9. Inlet solenoid (A) open (B) closed
3. Recycling pump motor 10. Outlet solenoid (A) closed ( B ) open
4. Recycling pump 1 1 . Brake caliper
5. High-pressure accumulator (damping 12. Rpm sensor
chamber) 13. Phonic wheel
6. Brake pump 14. Constriction
7.
Servo unit
In this phase the electronic control unit (1) earths the inlet solenoid (9) w h i c h closes, w h i l e the outlet
solenoid (10), not being connected t o earth, is already closed.
The hydraulic connection between t h e brake p u m p (6) and brake caliper (11) is interrupted (waiting
position).
The pressure in the brake caliper (11) is kept constant at the value reached previously, whatever the
pressure on the brake pedal.
Even t h o u g h the braking force maintains a continuous slowing d o w n action, the wheel varies its speed
in accordance with the grip on the ground, until the rpm sensor (12) measures a value w h i c h is compa-
rable to the reference speed calculated by the electronic control unit ( 1 ) .
At this point, the control unit passes from the maintenance phase to the pressure increase phase (if the
wheel accelerates) or reduction phase (if the wheel is tending to lock).
16
Publication no. 506.670