Rail Components Parts; Rail Pressure Sensor (Pc Sensor); Pressure Limiter; Operation Section - Denso 4D56 Service Manual

6. RAIL COMPONENTS PARTS

6.1 Rail Pressure Sensor (Pc Sensor)

The pressure sensor detects the fuel pressure of the rail, and sends a signal to the engine ECU. The sensor is made from a semicon-
ductor that uses the Piezo resistive effect to detect changes in electrical resistance based on the pressure applied to the elemental sili-
con. In comparison to the old model, this sensor is compatible with high pressure.
A-VCC

6.2 Pressure limiter

The pressure limiter releases pressure when the internal pressure of the rail becomes abnormally high. The pressure limiter opens when
internal pressure reaches 221MPa (2254 kg/cm2) and closes when rail pressure reaches a given set pressure. Fuel released from the
pressure limiter is returned to the fuel tank.
To fuel tank
A-GND
PEUFL
From rail

Operation Section

Vout/Vc
Vc = 5V
0.84
0.712
0.52
0.264
0.2
0 20 100
Popt
Valve Open
Valve Close
50 MPa (509.5 kg/cm 2 )
1
160 200
(Mpa)
Q001238E
221 MPa (2254 kg/cm 2 )
Q001239E
15
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