Exhaust Gas Recirculation: Description and Operation

Exhaust Gas Recirculation (EGR) System

Notes:
^ The function/control of the EGR system is provided by the Diesel direct injection system ECM, J248 via the EGR Vacuum Regulator solenoid valve N 18 to the mechanical EGR valve.
^ The cone shaped plunger in the mechanical EGR valve ensures that various cross sectional openings are possible at different plunger lifts.
^ Every, conceivable valve position is possible via pulsed control.
^ To cool the hot, recirculated exhaust gases they are fed through a heat exchanger (Exhaust Gas Recirculation cooler). This exchanger is an integral component of the coolant circuit and coolant flows through it constantly. This design serves to:
- Reduce exhaust gas temperatures
- Reduce exhaust emissions
- Reduce engine thermal loading
^ Replace self-locking nuts.