Exhaust Gas RECIRCULATION: Description
The Exhaust Gas Recirculation (EGR) system recirculates a small amount of exhaust gases during low engine loads, a larger amount during high engine loads and acceleration conditions, and provides no recirculation at idle or wide open throttle to assure maximum performance and a smooth idle. This complete modulation assures good engine performance at partial load coupled with effective NOx reduction.
On 2002, 530i and 3.0Si, system components include a two stage EGR valve, vacuum control valve, temperature controlled vacuum solenoid, and exhaust gas filter. On 630CSi, 633CSi and 733i, main components include an EGR valve, pressure transmitter, EGR filter, switching valves or thermo valve.