EGR Backpressure Transducer: Description and Operation

Component Description For The Exhaust Gas Recirculation Pressure Transducer







Location
The EGR [ARF] vacuum transducer is mounted behind the right cylinder head.

Task
The EGR pressure transducer controls the vacuum pressure to the EGR valve.

Design
The EGR pressure transducer is an electromagnetic proportioning valve.







Function
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 in proportion to the current flow in the coil. The vacuum acts partially or fully at connection OUT and operates the ERF valve accordingly.