B. Description of Supply Pump Components a. Feed Pump ‡ The trochoid type feed pump, which is integrated in the supply pump, draws fuel from the fuel tank and feeds it to the ‡ The feed pump is driven by the drive shaft. With the rotation of the inner rotor, the feed pump draws fuel from its suction two plungers via the fuel filter and the SCV (Suction Control Valve). 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.
5YERXMX](IGVIEWI 5YERXMX](IGVIEWI*YIP(MWGLEVKI 3YXIV6SXSV XS4YQT'LEQFIV -RRIV6SXSV -RXEOI4SVX JVSQ*YIP8ERO (MWGLEVKI 4SVX 5YERXMX]-RGVIEWI 5YERXMX]-RGVIEWI*YIP-RXEOI b. SCV: Suction Control Valve (Normally open type) 5() ‡ 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.
‡ Because only the quantity of fuel that is required for achieving the target rail pressure is drawn in, the actuating load of ‡ When current flows to the SCV, variable electromotive force is created in accordance with the duty ratio, moving the ar- the supply pump decreases. mature 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. ‡ With the SCV OFF, the return spring contracts, completely opening the fuel passage and supplying fuel to the plungers.
‡ When the SCV is ON, the force of the return spring moves the cylinder to the right, closing the fuel passage (normally (Full quantity intake and full quantity discharge) opened). ‡ By turning the SCV ON/OFF, fuel is supplied in an amount corresponding to the actuation duty ratio, and fuel is dis- charged by the plungers. )\XIVMSV:MI[SJ7': 'VSWWWIGXMSRSJ7': 7': 6IXYVR7TVMRK 4YQT&SH] ']PMRHIV 5) (1) In case of short time ON duty -13-