3308493 - 1080C exhaust gas recirculation system (e.g.r.)

The system is equipped with an E.G.R. valve (1) in order to reduce the NOx (nitrogen oxide) emissions still further.The E.G.R. (Exhaust Gas Recirculation) valve carries out the function of taking some of the exhaust gases and returning them to the inlet chamber (2).The E.G.R. valve is operated by the vaccum modulated by the solenoid valve (3) controlled by the injection control unit.

VACUUM MODULATING SOLENOID VALVE

Operation

The vacuum arrives at chamber E from duct F (case I) because the force of the spring (6) acts on the moving element (4) and the deviation valve (5) allows it to pass.The vacuum then reaches chamber B and the surface of the shutter (3), via the compensation port D.When the forces acting on the disc (3) are balanced, the atmospheric pressure in duct A enters chamber B, moving the moving element downwards (case II) therefore the valve (5) shutter closes duct F and places chamber E in contact with chamber C, which is at atmospheric pressure, decreasing the value of the vacuum in duct E.The decreased vacuum value or the increased absolute pressure in chamber E raises the moving element (4) again (case I), closing port C and placing the valve (5) in the ideal condition (E in contact with F) and the cycle is repeated.--