Exhaust Gas Recirculation (EGR)

Exhaust gas recirculation (EGR)

Exhaust gas recirculation occurs as soon as the following conditions are met:
^ Coolant temperature between 60 °C and 110 °C
^ Battery voltage 11-14 Volt
^ Fuel rack travel < 9 mm
^ Engine speed up to approx. 3500 rpm

According to the input signals from sensors e.g. fuel rack travel, engine speed, etc., the EDS control unit calculates the corresponding volume of exhaust gas recirculation for the respective operating conditions.

Control current is applied to the vacuum transducer which delivers a respective amount of vacuum to the EGR valve.

The EGR volume is reduced as engine speed and load increase.
This means:
Increasing control current = increasing EGR volume
Decreasing control current = decreasing EGR volume.

In addition: EGR shut-off at 100 before full load via control linkage microswitch and switchover valve in vacuum line. As a result, smoke emission is reduced during load changes towards full load.

Block Diagram, EGR:

The EGR system with vacuum transducer, EGR switchover valve, EGR valve, air flow sensor and EDS control unit operates as a closed loop.