Fuel Injection Pump
The Bosch single plunger mechanical pump consists of a low-pressure, vane-type fuel pump, a high-pressure distributor-type plunger injection pump, a centrifugal governor, and an injection timing advance mechanism. Both pumps are equipped with an electrical fuel shut-off solenoid. See Figure.
As the vane type pump rotor turns, centrifugal force holds the vanes against the walls of the pump's pressure chamber. The offset design of the rotor and pressure chamber, squeezes trapped fuel between vanes and forces it out the delivery port.
Vane pressure of the Peugeot pump is 65-73 psi (4.6-5.1 kg/cm2 ) at 1600 RPM or 87-94 psi (6.1-6.6 kg/cm2 ) at 2200 RPM. The main pump increases this pressure to approximately 1800 psi (126 kg/cm2 ).
NOTE:
Vane pressures are given at pump speed, not engine speed and were not available for Volvo models.