E 320 4MATIC Wagon (210.282) V6-3.2L (112.941) (1998)
EGR Backpressure Transducer: Description and Operation
Exhaust Gas Recirculation Vacuum Transducer, Function
Exhaust Gas Recirculation Vacuum Transducer, Function
a
Compression spring
b
Valve plate with diaphragm
c
Housing, pressure regulator
d
Hose line (guides controlled vacuum of approx. -200 mbar to the electrical unit)
e
Coil
f
Electromagnetically operated valve unit
ATM
Atmospheric pressure, air admission via cylinder head
OUT
Controlled vacuum to EGR valve
VAC
Vacuum supply from intake manifold
From connection VAC the intake manifold vacuum reaches the pressure regulator, which stabilizes the intake manifold vacuum in line with engine speed
and throttle valve position via a control valve to approx. -200 mbar.
The controlled vacuum flows further via a hose line to the following electric unit.
This unit is actuated by the ME control unit with a pulse width modulation signal (frequency approx. 10 Hz, on/off ratio approx. 30 to 100%) at the
ground end. The developing magnetic field influences via the coil anchor the valve unit as follows:
- No signal from control unit:
The connections OUT and ATM are linked. The exhaust gas recirculation valve is close (ventilated).
- Signal from control unit:
The valve unit opens proportional to the current flow in the coil. The vacuum acts partially or fully at connection OUT and operates the ERF valve
accordingly.