Operation Section
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11
4. SUPPLY PUMP COMPONENT PARTS
4.1 Feed Pump
z The trochoid type feed pump, which is integrated in the supply pump, draws fuel from the fuel tank and feeds it to the two plungers
via the fuel filter and the SCV (Suction Control Valve). The feed pump is driven by the drive shaft. With the rotation of the inner rotor,
the feed pump draws fuel from its suction port and pumps it out through the discharge port. This is done in accordance with the space
that increases and decreases with the movement of the outer and inner rotors.
4.2 SCV ( Suction Control Valve )
z A linear solenoid type valve has been adopted. The ECU controls the duty ratio (the duration in which current is applied to the SCV),
in order to control the quantity of fuel that is supplied to the high-pressure plunger.
z Because only the quantity of fuel that is required for achieving the target rail pressure is drawn in, the actuating load of the supply
pump decreases.
z When current flows to the SCV, variable electromotive force is created in accordance with the duty ratio, moving the cylinder (inte-
grated with the armature) to the left side, and changing the opening of the fuel passage to regulate the fuel quantity.
z With the SCV OFF, the return spring contracts, completely opening the fuel passage and supplying fuel to the plungers. (Full quantity
intake and full quantity discharge = normally open)
z When the SCV is ON, the force of the return spring moves the cylinder to the left, closing the fuel passage (normally open).
z By turning the SCV ON/OFF, fuel is supplied in an amount corresponding to the actuation duty ratio, and fuel is discharged by the
plungers.
QD0708E
Outer Rotor
From
Fuel Tank
Intake Port
To
Pump Chamber
Discharge
Port
Quantity Decrease
Quantity Increase
Quantity Decrease
(Fuel Discharge)
Quantity Increase
(Fuel Intake)
Inner Rotor
Q001113E
Valve body
Needle valve
Return Spring
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