US Patent 9574500 Direct metering using a variable displacement vane pump

A direct metering architecture is provided having a metering pump and a servo pump wherein the metering and servo pumps are driven by an engine shaft by way of a gearbox transmission. The system reduces wasted horsepower previously occurring with oversized fixed displacement pumps, reduces instances of engine flameout and reduces the amount of heat added to fuel which ultimately improves engine oil cooling.