Exhaust Gas Recirculation: Description and Operation

Integral Back Pressure EGR Valve:

The Exhaust Gas Recirculation (EGR) system recirculates exhaust gas to the engine air intake under average vehicle driving conditions, to reduce combustion temperatures and exhaust gas NOx content.
The Integral Back Pressure (IBP) transducer EGR valve combines inputs of back pressure and EGR port vacuum into one unit. The valve requires both inputs to operate, and will not operate on vacuum alone.
The system utilizes a temperature sensitive vacuum control valve to control vacuum to the EGR valve during engine warm up. The control valve bleeds the EGR vacuum signal to atmosphere until normal operating temperature is achieved.