Crown Victoria V8-4.6L SOHC VIN 6 (1996)
Pressure Feedback Exhaust Sensor: Description and Operation
Differential Pressure Feedback EGR (DPFE) Sensor
PURPOSE
The Differential Pressure Feedback (DPFE) Sensor outputs a voltage proportional to the pressure drop across the metering orifice which is
supplied to the Powertrain Control Module (PCM) as Exhaust Gas Recirculation (EGR) flow rate.
OPERATION
Exhaust Flow Rate Detection
THE DPFE receives the exhaust pressure signals through two hoses referred to as the downstream pressure hose (REF SIGNAL) and the upstream
pressure hose (HI SIGNAL). As Exhaust Gases flow past the upstream pressure hose and through the metering orifice, a pressure drop is created
and detected at the downstream hose.
Exhaust Gas Flow Rate Control
This pressure drop results in a reference signal used by the PCM to know the exhaust gas "flow rate". The PCM then commands the EGR Vacuum
Regulator to vary the position of the EGR valve. By using the DPFE signal as a reference and the EGR valve as a "regulator," the PCM can more
accurately assess and control the amount of exhaust gases flowing into the intake manifold.
CONSTRUCTION
The DPFE sensor is a ceramic capacitive type pressure Transducer.
