[4] PCV (pump control valve) The PCV regulates the volume of fuel discharged by the supply pump in order to regulate rail pressure. The volume of fuel discharged by the supply pump to the rail is determined by the time at which current is applied to the PCV. Key switch PCV relay +B ECU PCV1 PCV2 PCV Q000088E [5] Trochoid Type Feed Pump The feed pump, which is housed in the supply pump, draws fuel up from the tank and delivers it to the chamber via the fuel filter. The feed pump rotor is driven by the camshaft. The rotation of the camshaft causes the outer and inner rotors to rotate.
At this time, the suction port side pump chamber volume (the space surrounded by the outer and inner rotors) increases gradually, causing the fuel entering from the fuel inlet to be drawn into the pump chamber via the suction port. Along with the rotation of the rotor, the fuel that has been drawn in moves to- wards the discharge port and is discharged. The discharged fuel travels via the fuel outlet and is fed into the supply pump body.
Volume decreased (while moving to discharge port) Volume decreased (while discharging fuel to discharge port) Outer rotor To pump chamber Inner rotor Suction port Discharge port From fuel tank Volume increased (while drawing in fiel) Volume increased (while drawing in fiel) Q000090E [6] Coupling The coupling is an intermediary device that transmits the engine driving torque to the supply pump camshaft. Coupling Q000091E 8