Caterpillar Inc.

Norval J Wiemken

Alan Ray Stockner

Ye Tian

Scott F Shafer

Mark S Cavanagh

Jay E Tomaseski

Steven Y Tian

Gene Ray Slinkard

Norman David Knapp

Michael Anthony Haughney

Yongxin Wang

Devin C Tornow

Mehrdad Mojarrad

A common rail fuel injector comprises a three-way control valve that controls the flow of high-pressure fuel to a fuel cavity for fuel injection. Specifically, when the control valve is transitioning to a first, on position, from a second, off position, high-pressure fuel is provided to both the fuel cavity and to a check control cavity, thereby preventing fuel injection until the control valve seats in the first, on position. Once seated in the first, on position, the control valve only provides high-pressure fuel to the fuel cavity allowing fuel injection to occur. To stop injection, the control valve is moved from the first, on position to the second, closed position. Once again, while the control valve is in the transition location between the two positions, high-pressure fuel is provided to both the fuel cavity and to the check control cavity thereby terminating injection. Once the control valve is seated back in the second, closed position, the fuel cavity and the check control cavity are fluidly connected.

Common rail fuel injector

Because of the relatively high pressures experienced within fuel injectors, several internal components can undergo substantial deformation each time fuel is pressurized to injection levels. In some instances, such as when a solenoid operated control valve is positioned near a distortion region, the internal distortion can cause a fuel injector to behave with less predictability, and can undermine consistency from one fuel injector to another, since distortion levels and affects therefrom are likely to vary substantially from one injector to another. In order to desensitize fuel injector performance to this internal distortion, a deflection cavity is disposed within the fuel injector between the distortion region and the needle valve of the fuel injector. This strategy finds particular applicability to needle control valves disposed deep within fuel injectors in order to control fluid pressure on a closing hydraulic surface of a direct control needle valve, which opens and closes the nozzle outlets.

Desensitizing armature air gap to component distortion in a fuel injector

The present invention relates to high speed control valves which are especially applicable for use in fuel injection systems. Producing a valve with a quick response time within acceptable packaging constraints and with a structure that allows the valve to be mass produced with consistent performance between valves is extremely problematic. By moving flow restrictions within the valve away from the valve seats, flow forces on the valve member can be reduced, while possibly also permitting a reduction in the necessary travel distance of the valve member to improve response time and other performance characteristics. The valve is particularly applicable in controlling hydraulic pressure applied to the closing hydraulic surface of a direct control needle valve in a fuel injector.

Three way valve and electro-hydraulic actuator using same

A common rail fuel injection system addresses three basic issues involving all common rail fuel injection systems. These include high performance, low variability and high efficiency. These issues are addressed by combining pressure intensification with a three way needle control valve, which exhibits substantial leakage only durring a brief instant when the valve is moving between seats. A quick acting needle control valve tightly coupled to a responsive direct control needle valve, as modified by relative timing with a flow control valve, can produce a wide variety of fuel injection rate shapes, including up to five or more discrete injections per engine cycle.

Hydraulic fuel injection system with independently operable direct control needle valve

A nozzle assembly for fuel injection in an internal combustion engine comprising a nozzle tip with a hollow interior defining a fuel chamber. The nozzle tip has at least one spray orifice opening to an outer surface on the nozzle tip, and a valve member at least partially disposed within the nozzle tip. The valve member is moveable between a first position in which the valve member contacts an upper valve seat to prevent fluid communication of fuel from the fuel chamber to the at least one spray orifice, and a second outward position in which the valve member contacts a lower valve seat to allow fluid communication of fuel from the fuel chamber to the at least one spray orifice. The valve member is directly electrically actuated, preferably by a solenoid. Further, the valve member is biased in the closed position and the valve member is pressure balanced when high pressure fuel in present in the fuel chamber.

Fuel injector nozzle with outwardly opening check valve

A cyclic high pressure fluid seal for a fuel injector includes an injector body that defines a cyclic high pressure space connected to a low pressure space by a bore. A member with a pressure face end and a side surface is mounted to reciprocate in the bore between a retracted position and an advanced position. An O-ring is positioned in contact with the side surface of the member and the injector body within the bore. A portion of the member and the bore define a pressure accumulation volume positioned between the O-ring and the pressure face end. The pressure accumulation volume is positioned such that fluid pressure in the pressure accumulation volume changes with that of the cyclic high pressure space.

Fluid seal for cyclic high pressures within a fuel injector

A hydraulically actuated fuel injector includes an injector body defining an actuation fluid chamber that opens to an actuation fluid drain, an actuation fluid inlet and a piston bore, and further defining a nozzle chamber that opens to a plunger bore and a nozzle outlet. A control valve, positioned in the injector body, has a first position that opens the actuation fluid inlet and closes the actuation fluid drain, and a second position that closes the actuation fluid inlet and opens the actuation fluid drain. A piston, positioned in the piston bore. A plunger, positioned in the plunger bore, is moveable between an upper position and a lower position. A needle valve member, positioned in the nozzle chamber, is moveable between an open position in which the nozzle outlet is open and a closed position in which the nozzle outlet is blocked. A portion of the plunger bore and the plunger define a fuel pressurization chamber that opens to the nozzle chamber. A variable rate return spring biases the piston and plunger toward their retracted positions. The variable rate return spring has a relatively low spring rate when the piston is a first distance away from its retracted position and has a relatively high spring rate when the piston is at a second distance away from its retracted position.

Hydraulically-actuated fuel injector with variable rate return spring

A hydraulically actuated fuel injection system includes an actuation fluid supply pipe having a flange. A hydraulically actuated fuel injector has a centerline, at least two different clamping surfaces and a side surface with an actuation fluid inlet. The clamping surfaces are positioned on opposite sides of the centerline. A clamp is attached to the flange of the actuation fluid supply pipe around the centerline of the injector while bearing against the at least two different clamping surfaces. The clamp allows for reliable sealing in a small space while minimizing internal distortion to injector components.

Space saving high pressure fluid supply clamp for a fuel injector

A fuel injector includes an injector body with a plunger bore that opens to a nozzle outlet. A plunger having a pressure face and a side surface is positioned to reciprocate in the plunger bore between an advanced position and a retracted position. A portion of the plunger bore and the plunger define a fuel pressurization chamber that opens to the nozzle outlet. A needle valve is positioned in the injector body adjacent the nozzle outlet and is moveable between an open position which opens the nozzle outlet and a closed position in which the nozzle outlet is closed to the fuel pressurization chamber. An O-ring is in contact with the side surface of the plunger and the plunger bore on the injector body and serves to seal against fuel leakage past the plunger. Pressure acting on the O-ring is attenuated by providing either a pressure accumulation volume between the pressure face end of the plunger and the O-ring and/or a pressure release passage that opens the plunger bore to a low pressure return line below the O-ring.

Fluid seal for cyclic high pressures within a fuel injection

A dual-function clamping assembly adapted for i) connecting a hydraulically-actuated injector to an engine member, such as a cylinder head, and ii) for sealedly connecting an actuating fluid supply passage between the engine member and an actuating fluid inlet passage of the injector located at one end portion of the injector. The clamp assembly is applicable, for example, for angled-body injectors having the actuator and valve assembly positioned offset from and angled relative to the main longitudinal axis of the injector body.

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Dwight, IL, United States of America

Norval J Wiemken