Valve Configuration For Single Piston Fuel Pump

1 . A single piston fuel pump comprising a pump inlet and an outlet and mounting a proportional solenoid operated inlet metering valve with variable orifice, an inlet check valve, a pumping chamber, a pumping piston and sleeve, an outlet check valve, and a pressure relief valve, wherein the inlet metering valve and the inlet check valve are mounted on a common axis.

2 . The pump of claim 1 when the outlet check valve and pressure relief valve are mounted on a common axis.

3 . A single piston fuel pump comprising a pump housing having a pump inlet and an outlet and mounting a proportional solenoid operated inlet metering valve with variable orifice, an inlet check valve, a pumping chamber, a pumping piston, an outlet check valve, and a pressure relief valve, wherein the inlet metering valve, the inlet check valve, the outlet check valve, and the pressure relief valve are all mounted on a common axis.

4 . The pump of claim 3 , wherein the pumping chamber is between the inlet check valve and the outlet check valve, and the pumping plunger reciprocates within the plunger sleeve on a pumping axis aligned perpendicularly to the flow axis.

5 . The pump of claim 4 , wherein the inlet includes an inlet plenum and the orifice is an axially aligned slot that is selectively increased and decreased to present variable flow cross-section as the inlet metering valve piston is farther and closer to the check valve, respectively.

6 . The pump of claim 5 , wherein the check valve is disposed between said slot and said pumping chamber.

7 . The pump of claim 4 wherein said metering valve and said check valve are contained in a sub-assembly mounted in the pump housing.

8 . The pump of claim 4 wherein said outlet check and said pressure relief valve are contained in a sub-assembly mounted in said pump housing.

9 . The pump of claim 5 wherein said metering valve and said check valve are in a contained in a first sub-assembly and said outlet check valve and said relief valve are mounted in a second sub-assembly, said sub-assemblies being mounted in said pump housing on opposite sides of said pumping chamber.

10 . The pump of claim 9 wherein the first and second sub-assemblies are coaxial.

11 . The pump of claim 9 wherein said sub-assembly for said metering valve and said check valve includes a valve body having a bore therein, a piston operated by a solenoid mounted in said bore, a plenum in said pump housing, an orifice in said sleeve communicating with said bore, the piston arranged to reciprocate to provide variable opening of the orifice into bore.

12 . The pump of claim 11 wherein said check valve includes a valve seat in said valve body, a ball spring biased against said seat, said valve seat being positioned between said orifice and said pumping chamber.

13 . The pump of claim 12 wherein said sleeve of sub-assembly for said metering valve and said check valve is mounted in a bore in a pump housing.

14 . The pump of claim 9 wherein said sub-assembly for said outlet check valve and said relief valve includes a sleeve having a bore therein, a valve seat member having a sealing face thereon mounted in said sleeve, a valve plate spring biased against said sealing face, and a passageway through said valve body providing communication between said pumping chamber and the bore downstream of valve member.

15 . The pump of claim 14 wherein said sub-assembly for said outlet check valve and said relief valve further includes a second passageway through said valve seat member, a plenum in said sleeve communicating with the bore downstream of said valve plate, said second passageway providing communication between said plenum and the interior of the sleeve upstream of the valve seat member, a valve seat on the face on the inner against which a valve member of the relief valve is biased.

16 . The pump of claim 15 wherein said sleeve of the sub-assembly assembly for said outlet check valve and said relief valve is mounted in a bore in a pump housing.