Fiat 1996 Brava Service Manual page 374

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98 range
JTD
Engine
Fuel system
10.
EGR MODULATING VALVE
The vacuum coming from the vacuum pump for the brake servo reaches the chamber (E) from the duct
(F) (case I), because the force of the spring (6) acts on the moving element (4) and the valve (5) allows
its passage.
The vacuum then affects the chamber (B), through the compensation port (D) and the surface of the
shutter (3).
When the forces acting on the disc (3) are in equilibrium, the atmospheric pressure in the duct (A) en­
ters the chamber (B), moving the moving element downwards (case II), so that the valve (5) shutter
closes the duct (F) and places chamber (E) in contact with chamber (C) at atmospheric pressure, de­
creasing the value of the vacuum in the duct (E).
The decreased vacuum value or the increase in
the absolute pressure in the chamber (E) raises
the moving element (4) (case I), closing the
passage (C) and placing the valve (5) in the
ideal condition (E in contact with F) and the cy­
cle is repeated.
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