Abstract: A fuel injector is provided that includes various precise configuration parameters, including dimensions, shape and/or relative positioning of fuel injector features, resulting in improved efficiency of fuel flow through the fuel injector.

Abstract: A piezoelectric-actuated fuel injector for injecting fuel into a combustion chamber of an internal combustion engine is provided which includes a piezoelectric actuator movable to expand in a first direction and movable to contract in a second direction opposite the first direction, and a hydraulic link assembly disposed within said injector cavity. The hydraulic link assembly includes a hydraulic link barrel having an inner bore, a hydraulic link outer plunger positioned to slidably move in the inner bore, and a hydraulic link operatively connected to a needle valve to move the needle valve in the second direction toward the open position in response to movement of the piezoelectric actuator in the first direction. A hydraulic link inner plunger is attached to the needle valve and extends into a center bore of the hydraulic link outer plunger. Leakage control features and hydraulic link refill valves are also provided.

Abstract: A piezoelectric-actuated fuel injector for injecting fuel into a combustion chamber of an internal combustion engine is provided which includes a piezoelectric actuator movable to expand in a first direction and movable to contract in a second direction opposite the first direction, and a hydraulic link assembly disposed within said injector cavity. The hydraulic link assembly includes a hydraulic link barrel having an inner bore, a hydraulic link outer plunger positioned to slidably move in the inner bore, and a hydraulic link operatively connected to a needle valve to move the needle valve in the second direction toward the open position in response to movement of the piezoelectric actuator in the first direction. A hydraulic link inner plunger is attached to the needle valve and extends into a center bore of the hydraulic link outer plunger. Leakage control features and hydraulic link refill valves are also provided.

Abstract: A fuel injector device, for injecting fuel into a combustion chamber of an internal combustion engine, has a nozzle valve and nozzle valve control assembly adapted to use a control valve and high pressure fuel in the fuel injector in order to actuate movement of the nozzle valve between an open position to inject fuel and a closed position to terminate fuel injection. The nozzle valve control assembly employs a pressure balancing control valve so that the fuel pressure exerts a zero net force on the control valve in a dimension along which the control valve moves. Thus, the actuation occurs independently of the fuel pressure. In addition, the actuator is operably connected to the control valve by at least a hydraulic linkage, where the hydraulic linkage compensates for changes in the actuator and the injector body due to changes in temperature.

Abstract: A fuel injector device, for injecting fuel into a combustion chamber of an internal combustion engine, has a nozzle valve and nozzle valve control assembly adapted to use a control valve and high pressure fuel in the fuel injector in order to actuate movement of the nozzle valve between an open position to inject fuel and a closed position to terminate fuel injection. The nozzle valve control assembly employs a pressure balancing control valve so that the fuel pressure exerts a zero net force on the control valve in a dimension along which the control valve moves. Thus, the actuation occurs independently of the fuel pressure. In addition, the actuator is operably connected to the control valve by at least a hydraulic linkage, where the hydraulic linkage compensates for changes in the actuator and the injector body due to changes in temperature.

Abstract: A reprogrammable electronic step timing control system having a fuel pressure threshold that is discretely variable as a function of engine speed. The fuel pressure threshold is increased for engine speeds above rated speed by a predetermined amount. A programming key is provided in a wiring harness to allow fuel pressure and speed thresholds to be readily changed.

Abstract: A three-way fuel injection control valve assembly is provided which includes a pilot valve for controlling the movement of a drain valve member and a separate supply valve member to minimize valve response time and transition flow losses. The solenoid operated two-way pilot valve controls the flow of fuel from a control volume formed adjacent the ends of the drain valve member and the supply valve member to begin and end an injection event. A transition flow loss limiting feature is provided which causes the drain valve member to close prior to the opening of the supply valve member and subsequently causes the supply valve member to close prior to the opening of the drain valve member during a given injection event thereby minimizing transition flow losses.

Abstract: A servo-controlled fuel injector is provided which includes a leakage limiting valve device for limiting the quantity of high pressure fuel available for leakage into the combustion chamber in the event the closed nozzle valve element fails to sealingly engage its seat between injection events. The servo-controlled fuel injector includes a control volume positioned adjacent an outer end of the nozzle valve element, a control volume charge circuit for supplying fuel to the control volume, a drain circuit for draining fuel from the control volume to a low pressure drain and an injection control valve positioned along the drain circuit for controlling the flow through the drain circuit so as to cause reciprocal movement of the nozzle valve element. The leakage limiting valve is integrated into the fuel injector body and positioned along a fuel transfer passage to block the flow of high pressure fuel to a nozzle cavity between injection events.

Abstract: An electromagnetic fuel injection control valve positioned inside a fuel injector, i.e. a unit injector, for providing fast response and high pressure capability while minimizing the size and complexity of the injector. The control valve includes a valve housing having a supply inlet and fuel outlet, a center tube having a center passage and an annular valve seat, a control valve sleeve slidably mounted on the center tube and an actuator assembly having a coil spring, a stator and an armature. The control valve sleeve moves between an open position permitting fuel to flow between the supply inlet and the fuel outlet and a closed position which sealingly engages the annular valve seat for blocking the flow of fuel between the supply inlet and the fuel outlet. The coil spring biases the control valve sleeve in an open position and is positioned around the center tube. The stator is also axially positioned around the center tube and includes multiple poles.

Abstract: A stepped rotation fuel distribution valve for receiving and conducting metered, pressurized fuel pulses to the combustion cylinders of a diesel engine is provided. The valve includes a fuel distribution shaft rotatably mounted in a valve housing. The shaft includes a fuel discharge port that is sequentially registrable with fuel distributing passages in the housing that ultimately lead to the diesel fuel injectors associated with the combustion cylinders of the engine. A drive mechanism, which may include a stepper motor, intermittently rotates the fuel distributor shaft so that the shaft discharge port dwells in registration with one of the fuel distributing passages at the time a pressurized pulse of fuel is discharged through the shaft discharge port. The drive mechanism may also include either a set of timing gears or a spring coupling to achieve the desired intermittent rotation.

Abstract: A unit fuel injector is provided comprising an injector body containing a pumping chamber for receiving fuel at a low pressure level from a fuel supply passage for subsequent discharge at a high pressure level, a discharge orifice and a transfer passage communicating with the pumping chamber and the discharge orifice. A valve element is provided for movement between (i) an advanced position wherein the supply passage communicates with the pumping chamber through the transfer passage and (ii) a retracted position wherein communication between the supply passage and the pumping chamber is blocked to allow fuel to flow from the pumping chamber through the transfer passage and out the discharge orifice.

Abstract: A hydraulic tappet for use in the fuel injector drive trains of compression ignition or diesel internal combustion engines are provided which optimize injector timing for improved fuel economy. One embodiment of the hydraulic tappet of the present invention includes a dampened pressure regulating feature which determines blow down pressure. A second embodiment of the hydraulic tappet of the present invention includes a dampening load cell feature which allows the blow down pressure of the load cell to be increased and injection timing to be optimally advanced.

Abstract: A unit fuel injector adapted for periodic injection of fuel into a combustion chamber of an engine at variable times from cycle to cycle under the control of the engine lubrication fluid is provided, comprising an injector body containing an injector cavity and a discharge orifice communicating with one end of the injector cavity to discharge fuel into the combustion chamber, a lubrication fluid timing circuit and a fuel metering circuit separate from the lubrication fluid timing circuit. A lubrication fluid link positioned in the lubrication fluid timing circuit within the injector cavity has a variable effective length which is varied by the operation of a control valve positioned within the lubrication timing circuit to vary the timing of injection. The control valve is operated to control the flow of lubrication fluid in the lubrication fluid timing circuit to control both the timing of injection and the metering of fuel on a cycle by cycle basis.

Abstract: A fuel injector for an internal combustion engine includes a main body including a timing bore, a timing plunger disposed in the timing bore, an electronically-operated solenoid valve assembled to the main body, a nozzle having a needle bore and an injection needle disposed in the needle bore which needle is operable under certain conditions to lift so as to initiate fuel injection. Disposed between the main body and the nozzle member is a one-piece adapter which is designed to include an axially-extending metering bore and a needle spring cavity. A metering plunger is disposed within the metering bore and a biasing spring is disposed within the needle spring cavity. At the base of the needle spring cavity is a button which serves as a direct abutment interface between the top of the needle and the bottom of tile biasing spring.

Abstract: The present invention is directed to open nozzle unit fuel injectors for injecting a metered quantity of fuel into the cylinder of an internal combustion engine, as synchronously controlled by a drive train, wherein the unit fuel injector comprises a body with an axial bore and a plunger assembly movable therein between a retracted position and an advanced position. The plunger includes a major diameter section, slidably movable in the axial bore to open and close a fuel supply orifice and a minor diameter section which extends in a bore of a cup portion of the injector body. The cup portion has an internal surface including plural diameter portions connected by an annular step.

Abstract: A unit fuel injector is disclosed to be used in a fuel injection system of an internal combustion engine wherein each unit injector is operated independently from one another and in synchronization with the internal combustion engine. Specifically, the unit injector in accordance with the present invention includes a reciprocating plunger assembly within the unit injector that controls fuel metering as well as fuel injection, and a valve device positioned between a minor diameter plunger section and a cup of the unit injector so as to permit fuel flow in one direction for fuel injection and to restrict flow of gases in the opposite direction. The valve device effectively reduces carbon build-up on the injector surfaces and increases injector longevity while reducing maintenance. Moreover, fuel metering is accurately controlled without substantial carboning flow losses.

Abstract: The present invention is directed to open nozzle type unit fuel injectors, and more specifically to an improved lower plunger and cup design of an open nozzle unit injector to minimize trapped volume and reduce unburned hydrocarbons in vehicle emissions. The lower plunger includes at least a major and a minor diameter sections with the minor diameter section extending within a bore of said cup at least partially between the fully advanced and retracted positions of the plunger. Moreover, the labyrinth flow area between the cup bore and the minor diameter section of the plunger is designed to reduce the trapped volume of fuel that results in the advanced plunger position while reducing sensitivity to fuel metering in the retracted plunger position. In one embodiment, the cup bore and minor diameter section are stepped. In another, both the bore and the minor diameter section are tapered. In yet another embodiment, only the cup bore is modified.

Abstract: This disclosure relates to a fuel injector for an internal combustion engine. The injector comprises an injector body forming a plunger bore, and a plunger reciprocably mounted in the bore. The plunger reciprocates between a retracted position and a forward position, and a fuel receiving or metering chamber is formed at the forward end of the bore when the plunger is in the retracted position. A fuel supply passage is formed in the body and conducts fuel to the chamber when the plunger is in the retracted position. When the plunger is moved forwardly in an injection stroke, it ejects the fuel from the chamber through spray holes formed in the body. The injector further includes means for selectively opening or closing the supply passage when the injector plunger is in the retracted position. Such means includes a land formed on the plunger adjacent the supply passage, a groove formed in the land, and means for rotating the plunger between two angular positions.

Abstract: This disclosure relates to a unit-type fuel injector for an internal combustion engine such as a reciprocating piston internal combustion engine. The injector includes an injector body forming a plunger bore, and a plunger that reciprocates in the bore. A fuel supply passage and a drain passage are formed in the body, and a fuel injection chamber is formed at the lower end of the plunger bore. A feed hole connects the chamber with the supply passage, and a scavenge passage connects the supply and drain passages. During a retracted plunger, or fuel metering, portion of the injector cycle, the plunger opens the feed hole and closes the scavenge passage, and during a down plunger, or scavenging, portion of the injector cycle, the plunger closes the feed hole and opens the scavenge passage. An annular groove is formed between injector parts and surrounds the chamber, and the groove collects leakage. A restricted bleed hole connects the groove with the low pressure drain and removes the leakage.

Abstract: The disclosure illustrates an anti-tampering fuel control valve for a fuel system providing fuel at a regulated pressure to a series of unit injectors on a diesel engine. The injectors are cam actuated to inject fuel quantities related to the pressure of the fuel supplied to them. The control valve bypasses fuel from the output of the fuel system to a low pressure region when the pressure exceeds a first given level because of fuel system tampering. Orifices in the bypass flow path cause the fuel pressure to follow a schedule generally similar to the normal system pressure schedule but at lower levels. Bypass flow is continued until the fuel system pressure drops to a lower pressure than the pressure at which bypass flow begins.