Abstract: A split discharge vane pump is disclosed having a pump body that includes an interior pumping chamber having a central axis and defining a continuous peripheral cam surface, the cam surface including four quadrantal cam segments, wherein diametrically opposed cam segments have identical cam profiles, and each cam segment defines an inlet arc, a discharge arc and two seal arcs. A rotor is mounted for axial rotation within the pumping chamber and a plurality of circumferentially spaced apart radially extending vanes are mounted for radial movement within the rotor, wherein the plurality of vanes define an equal number of circumferentially spaced apart buckets which extend between the rotor and the cam surface of the pumping chamber for carrying pressurized fluid.

Abstract: A multiple stage pump for delivering fuel to an engine is disclosed which includes a pump housing, a boost stage operable at engine start to draw fuel into the pump housing at a boost stage pressure, a first pumping stage operable upon engine start for receiving fuel from the boost stage and delivering the fuel from the pump housing to a fuel metering unit, a second pumping stage operable upon engine start and during engine cruise operation for receiving fuel from the boost stage and delivering the fuel from the pump housing to said fuel metering unit, and a switching valve in fluid communication with the first and second pumping stages, and configured to control fuel flow through the first pumping stage in dependence on changes in boost stage conditions such as pressure or shaft speed.

Abstract: A fuel system including a fuel pump metering unit (FPMU) for delivering fuel to an engine manifold with an ecology valve for draining and storing fuel from the engine manifold. The ecology valve includes a housing having a piston dividing the housing into a first side in fluid communication with an output of the FPMU and a second side in fluid communication with the engine manifold. An assembly connected between the FPMU and engine manifold selectively creates a pressure differential across the first and second side of the housing when the FPMU delivers fuel to the engine manifold. In a run position, the piston moves to decrease a volume within the housing interior as a result of the pressure differential. In a drain position, the piston moves to increase the housing volume within the interior and thereby pull and store fuel from the engine manifold.