[2] Description of Supply Pump Components (1) Feed Pump a. 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.
Outer Rotor to Pump Chamber Quantity Decrease Quantity Decrease (Fuel Discharge) Inner Rotor Intake Port Discharge Port Quantity Increase from Fuel Tank Quantity Increase (Fuel Intake) QD0708E (2) SCV: Suction Control Valve (Normally open type) a. 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. b. 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. c.
When current flows to the SCV, variable electromotive force is created in accordance with the duty ratio, moving the armature to the left side. The armature moves the cylinder to the left side, changing the opening of the fuel passage and thus regulating the fuel quantity. d. 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) e. When the SCV is ON, the force of the return spring moves the cylinder to the right, closing the fuel passage (normally opened). f.
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. Exterior View of SCV Cross-section of SCV Return Spring SCV Pump Body Cylinder 13 Q000270E