Egr Modulating Valve - Fiat Bravo Service Manual

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E G R M O D U L A T I N G V A L V E

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 w i t h 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 w i t h F) and the cy-

cle is repeated.