Stanadyne Corporation

Robert G Lucas

Ilija Djordjevic

Mark S Cavanagh

Yevgeniy Norkin

Kenneth R Morel

An inlet valve assembly for a fuel pump comprises a valve assembly inflow path and valve assembly outflow path; a magnetic valve member situated in an intermediate flow path fluidly linking the inflow path and the outflow path; a magnetic pole adjacent the valve member; and a selectively energizable coil for generating a magnetic flux directly magnetically coupling the pole and the valve member; whereby the valve member opens and closes fluid communication between the inflow path and the outflow path in response to the energized state of the coil.

Direct magnetically controlled inlet valve for fuel pump

In a fuel pump and method of operation, an infeed for low pressure fuel leads to a pumping chamber where in an intake phase low pressure fuel is drawn into the pumping chamber and in a pumping phase high pressure fuel is delivered to a common rail. An inlet metering valve and an inlet check valve are upstream of the pumping chamber, and a control system closes the metering valve when no fuel is to be pumped to the common rail. The inlet check valve is also opened while the inlet metering valve is closed and no fuel is to be pumped to the rail. The inlet metering valve can include a proportionally controlled piston that produces a variable quantity of feed fuel and is closable for the no-demand condition with a maximum travel that contacts and holds open the inlet check valve.

Electronically controlled inlet metered single piston fuel pump

In a tappet-driven single piston pump, piston side loads caused by return spring out-of-squareness are eliminated by effectively piloting the piston return spring, preferably the associated spring seat, by the tappet, thereby allowing the tappet to bear the spring side load. The piston engages and is returned by the spring seat, but radial clearance between the piston and spring seat is greater than radial clearance between the spring seat and tappet, thus eliminating side loading imparted to the piston. The spring seat can be considered a piston retainer, in which the piston is not closely attached to the retainer but instead exhibits a predefined radial clearance greater than the piloting clearance between the retainer and the tappet.

Single piston pump with reduced piston side loads

The pump delivered pressure is regulated to a substantially constant set value, and output flow is varied by an inlet metering valve () via feedback from the motion of, or flow from the spilled fuel through, a delivered pressure regulator (). The pressure regulating element can be biased to close a seal surface (') against flow from the outlet side of the pump () toward the inlet metering valve when the pump is turned off, thereby holding sufficient rail pressure to prevent boiling during hot soak conditions. In another aspect, a flow stabilization orifice () is provided between the outlet of the pump and the inlet metering valve, e.g., upstream of the pressure regulating element. In yet a further aspect, the inlet metering valve is hydraulically responsive (, S, L) to changes in flow resulting from movement of the pressure responsive element ().

Constant pressure self-regulating common rail single piston pump

A fuel pump has a low pressure fuel inlet () and a single piston pumping chamber () for supplying high pressure fuel through a pump outlet to an inlet side of a common rail (). The fuel pump comprises a primary pressure relief valve () having an inlet side in hydraulic communication with the inlet side of the common rail () and an outlet side in fluid communication with the pumping chamber (); and an auxiliary pressure relief valve () having an inlet side () in hydraulic communication with the pumping chamber () and an outlet side in direct fluid communication with a fuel passage () at the low pressure of the pump inlet ().

Auxiliary pressure relief valve in single piston fuel pump

An atomizing injector comprises a body having a central bore with a valve situated in the bore, leading to a chamber. An actuator moves the valve between closed condition and open conditions, selectively exposing the chamber to a flow of pressurized liquid. A discharge port extends from the chamber to a discharge orifice. A swirl element is situated in the chamber, while leaving a free space in the chamber immediately above the discharge port. When the valve is opened, liquid flows into the chamber, through the swirl element into the space, forming a whirl in the space before passing through the discharge port and exiting the discharge orifice as an atomized whirling spray.

Injector having swirl structure downstream of valve seat

A fuel pump including a low pressure infeed leading to a pumping chamber, a pumping plunger for pressurizing fuel in the pumping chamber, an outlet valve for delivering pressurized fuel from the pumping chamber to a high pressure outlet line during pumping, and an overpressure relief valve connected between the high pressure outlet line and the pumping chamber. A ball type relief valve element is spring biased to close against the relief valve seat. The spring is in a spring chamber that is fluidly isolated from the pumping chamber while the valve element is closed, preferably in direct hydraulic communication with the low pressure infeed, thereby reducing dead volume during normal pumping. The spring can act on the valve element through a piston, and in an alternative embodiment, the piston can provide a spill path from the pumping chamber to the low pressure infeed.

Pressure relief valve for single plunger fuel pump

A damper assembly for a fuel pump includes at least one diaphragm assembly formed by joining two metal diaphragms to respective two sides of an imperforate central plate, thereby creating a pair of closely spaced diaphragms, each acting upon its own gas volume. Preferably, the diaphragm assembly has (a) a circular or polygonal central plate, (b) a first circular diaphragm having a rim portion sealingly secured as by welding to the plate and a relatively thin, flexible, convex portion projecting from one side of the plate and defining a first pressurized gas volume, and (c) a second circular diaphragm having a rim portion sealingly secured as by welding to the plate and a relatively thin, flexible, convex portion projecting from the other side of the plate and defining an independent second pressurized gas volume. The diaphragm assembly can be supported radially inside, outside, or on the weld.

Three element diaphragm damper for fuel pump

A damper assembly for a fuel pump includes at least one diaphragm assembly formed by joining two metal diaphragms to respective two sides of an imperforate central plate, thereby creating a pair of closely spaced diaphragms, each acting upon its own gas volume. Preferably, the diaphragm assembly has (a) a rigid, relatively thick circular or polygonal central plate, (b) a first circular diaphragm having a rim portion sealingly secured as by welding to the plate and a relatively thin, flexible, convex portion projecting from one side of the plate and defining a first pressurized gas volume, and (c) a second circular diaphragm having a rim portion sealingly secured as by welding to the plate and a relatively thin, flexible, convex portion projecting from the other side of the plate and defining an independent second pressurized gas volume.

A clamping and seal loading technique for securing the plunger sleeve to the pump housing of a single plunger fuel pump. This is achieved by providing a load ring between a sleeve retainer and the sleeve, such that the axial force applied by the retainer during installation and attachment to the plunger bore wall of the housing, is distributed more evenly on the sleeve and the sealing surface of the sleeve against the housing adjacent to the pumping chamber. The even distribution of force minimizes misalignment of the sleeve and thus maintains concentricity between the sleeve and the plunger.

Load ring mounting of pumping plunger sleeve

Pump piston seizures caused by excessive side loads produced by the uneven loading of a large piston return spring are prevented by separating the tappet return function from the piston return function, thereby minimizing the spring force acting on the piston. Preferably, a stronger, heavier load outer spring is mounted between the pump body and the tappet, such that it imparts no load and therefore no side loads to the pumping piston. A weaker, lighter load inner spring imparts less side load to the pumping piston than a conventional piston return spring, because the inner spring need not carry any tappet load. During both the pumping and charging strokes of the piston, the piston return spring can assist the tappet return spring, but the tappet return spring does not assist the piston return spring.

Single piston pump with dual return springs

A urea solution injection system and an injector with which urea solution or other exhaust treatment liquid from a source tank can be injected as an atomized spray into an exhaust pipe. A metering pump with integrated injection nozzle are contained in a common housing mounted directly to the exhaust pipe, thereby eliminating the separate electric motor driven pump, line between pump, and injector in conventional systems.

Integrated pump and injector for exhaust after treatment

A high pressure piston fuel pump having a discharge check valve between the pumping chamber and a pressurized fuel reservoir and a pressure relief valve between the fuel reservoir and a passageway in the housing, wherein the discharge check valve and the pressure relief valve are contained within a single fitting assembly affixed at the pump housing. A first end flow passage is in fluid communication with the pumping chamber and provides an inlet to the discharge check valve and an outlet from the pressure relief valve. A second end flow passage is in fluid communication with the fuel reservoir and provides an outlet for the discharge check valve and an inlet for the pressure relief valve. Advantages include the ability to pre-test the outlet check and pressure relief prior to assembly into the pump housing, and improved flexibility of the outlet fitting location.

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Ellington, CT, United States of America

Robert G Lucas