A fuel metering pump provides a compact and reliable fuel delivery system
meeting the stringent contamination resistance, accuracy, pressure and
flow requirements of jet engine combustion. The metering pump has a motor
driven dual face cam drive arrangement that reciprocates a pair of
double-acting spool pistons to both pump and meter fuel to the engine.
The motor rotates the cam shaft mounted face cams, which have oppositely
clocked ramps on which rollers ride to transfer the rotation forces from
the face cam to reciprocate the pistons. The double-acting pistons each
provide both compression and suction on each stroke. The tandem face cams
arranged at opposite sides of the cam followers provides consistent and
precise metering with minimal pulsation. Low pressure drop at the inlets
allows the metering pump to operate very near true vapor pressure without
risk of cavitation or the need for a boosted inlet.