Abstract: A method and apparatus for rate shaping a fuel injection profile in a diesel engine. The system includes a fuel injector having a pump chamber, a fuel injecting plunger, a supply line, and a discharge nozzle. A rotation of a camshaft causes reciprocation of the plunger and movement of fuel from the supply line through the chamber to the corresponding cylinder. A spill valve is positioned between the chamber and the nozzle, the valve having a first position providing a maximum fuel injection rate, a second position providing a substantially zero fuel injection rate, and at least one intermediate position providing an intermediate fuel injection rate.

Abstract: A fuel injection apparatus for an internal combustion engine is provided which is designed to control a fuel discharge from a fuel injection pump by regulating the quantity of fuel sucked into the fuel injection pump. The fuel injection pump is driven in synchronism with rotation of the engine to pressurize and supply the fuel to an accumulator chamber from which the fuel is injected into cylinders of the engine. The solenoid valve moves a valve member linearly to open and close a fluid path leading to the fuel injection pump. The controller actuates the solenoid valve in one of a first control mode when the engine speed is low and a second control mode when the engine speed is high. In the first control mode, a valve on-duration in which the solenoid valve is turned on to open the fluid path through the valve member and an area of the fluid path opened by the valve member are both controlled. In the second control mode, only the opened area of the fluid path is controlled.

Abstract: A fuel injection valve for internal combustion engines, having an axially movable valve member which, with its end oriented toward the combustion chamber, opens and closes a through flow cross section to at least one injection opening and which, with its end remote from the combustion chamber, protrudes into a fuel-filled spring chamber in which a valve spring is clamped, which acts on the valve member in the closing direction and is supported with its end remote from the valve member against a deflecting piston which, during the supply of high pressure fuel to the fuel injection valve, can be moved a certain distance into the spring chamber and thereby increases the initial stress force of the valve spring, and having a connecting conduit between the spring chamber and a low pressure fuel chamber. The connecting conduit between the spring chamber and the low pressure fuel chamber is embodied as a throttle bore in order to increase the injection opening pressure.

Abstract: In a method for operating a Diesel engine with a pump-line-nozzle injection system, which allows the pressure level to be raised in the lower and intermediate engine speed ranges in relation to a predetermined maximum permissible injection pressure without this maximum permissible injection pressure being exceeded in the upper engine speed range by providing an injection pump designed to deliver the desired fuel injection pressure at low and intermediate engine speeds and including a pressure relief valve in the fuel injection line permitting limiting of the fuel injection pressure at higher engine speeds.

Abstract: An injection valve for a fuel injection system, for multistage control of the effective cross section of an injection opening. A spring/stop system with a first compression spring for a control valve for a control chamber, whose pressure determined the position of the valve shaft of an injection valve member. When a valve opens, the spring/stop system allows its valve tappet a first axial stroke, which is limited by a primary stop on an axially movable adapter. The axial mobility of the adapter allows the valve tappet, counter to the compressive force of a first compression spring, an additional, second axial stroke, which is limited by an end stop structurally connected to the housing. The valve tappet is urged in the closing direction of the control valve by a second compression spring braced against the housing of the injection valve, and in the closed state of the control valve the spring force of the second compression spring is less than that of the first compression spring.

Abstract: An apparatus for producing a variable volumetric flow in a fuel feed system includes a high-pressure pump having at least one inlet, at least one cylinder, at least one piston each moveable in a respective cylinder, and a shaft driving the at least one piston. A metering device is disposed in the at least one inlet of the high-pressure pump, is synchronized with the shaft and feeds a variably meterable volume of fuel to the at least one cylinder during each revolution of the shaft. Metering is performed by varying an angle between opening and closure of the at least one inlet.

Abstract: A fuel injector including a delay device, the fuel injector having an electric controller for controlling the flow of a high pressure actuating fluid responsive to initiation and cessation of a pulse width command, the pulse width command defining the duration of an injection event, and an intensifier being in fluid communication with the controller, the intensifier being translatable to increase the pressure of a volume of fuel for injection into the combustion chamber of an engine; the delay device includes an apparatus, shiftable between a first disposition and a second disposition over a certain period of time after initiation of the pulse width command, the period of time effecting a delay in initiation of fuel injection after initiation of the pulse width command. In one embodiment, a bias against shifting the apparatus from said first disposition to the second disposition is effected by the actuating fluid to reduce variations in the delay period under variable actuating pressure conditions.

Abstract: A fuel injection system for an internal combustion engine with a reservoir for pressurised fuel and at least one fuel injector which has a solenoid activated valve to control fuel pressure therein, and including a control piston linked to the injector's valving member and defining a control space communicated with the injector's fuel, and further including a pressure regulating valve assembly with another solenoid activated valve operated independently of the injector's solenoid valve and which is located between the reservoir and the fuel injector for selectively creating different flow control configurations to regulate fuel pressure delivered to the injector. The two solenoid activated devices providing an injector control for providing flexible opening operation of the injector at more than one fuel pressure level.

Abstract: A hydraulically-actuated electronically-controlled fuel injector for use with a fuel injection system having an actuating fluid high pressure common rail for conveying an actuating fluid under pressure, the pressure of the actuating fluid in the common rail being selectively variable, the fuel injection system being installed on a diesel engine, the injector having a controller valve for selectively porting the actuating fluid to an injector intensifier assembly for magnifying the pressure of the fuel to be injected, includes a needle valve for controlling the opening and closing of a fuel injection orifice to effect a fuel injection event, the needle valve being shiftable between a closed disposition and an open disposition, a return spring exerting a bias on the needle valve tending to urge the needle valve into the closed disposition.

Abstract: A fuel injection system, comprising a low pressure fuel delivery pump with constant output in fluid communication with a low pressure fuel line; said fuel line connected to an electronic controlled fuel pressure regulator and fuel pressure sensor; an electronic control module to monitor and adjust fuel pressure in said low pressure fuel line to a desired fuel delivery pressure and supply fuel to an injector at a feed-back controlled pressure; and at least one injector in fluid communication with a cylinder in an internal combustion engine; said injector having an injector body equipped with a fuel metering orifice to supply fuel from the fuel line to a fuel cumulative chamber within the injector, a reciprocating plunger within said injector; said plunger equipped with a plunger; said plunger passage opening at one end to said fuel cumulative chamber, and, upon reciprocation of the plunger within the injector, opening at its other end to said metering orifice; said injector further equipped with an electronic

Abstract: A fuel injector assembly for an internal combustion engine including an injector body in fluid communication with a source of fuel and a nozzle assembly through which the fuel is dispersed from the fuel injector assembly during an injection event. A high pressure fuel delivery system provides high pressure fuel to the nozzle assembly. In addition, the fuel injector assembly includes a combined initial injection and peak injection pressure regulator which is operable to control the nozzle assembly to regulate the rate of fuel injection at the beginning of an injection event and is further operable to limit the maximum pressure of the fuel dispersed from the nozzle assembly.

Abstract: The injection valve has a control valve with a control chamber in which a closing member is disposed. The closing member is pressed against a corresponding sealing seat by a pressure (e.g. fuel pressure) in the control chamber. The closing member merges into a rod that passes through a drain hole and is connected to a spring plate. The spring plate is preloaded against the housing by a compression spring in such a way that the closing member is pressed against an associated sealing seat. The closing member can be raised from the sealing seat by an actuator piston which rests against the spring plate.

Abstract: Pumps and injectors utilize a control valve having a valve body with a valve stem having a step adjacent to the seating surface. The step extends a limited distance away from the seating surface to provide limited pressure relief when the valve body is at an intermediate position that is between the opened and closed positions. Step cross-section and axial length may be configured based on desired hydraulic behavior. In a preferred embodiment, the control valve step is configured for injection rate shaping.

Abstract: The invention proposes a fuel injection valve for internal combustion engines, having a valve member (11), which can be displaced axially outward in a bore (9) of a valve body (1) counter to the force of a closing spring (47) and which on its end toward the combustion chamber has a closing head (13), protruding from the bore (9) and forming a valve closing member, that on its side toward the valve body (1) has a valve sealing face (15) with which it cooperates with a valve seat face (17) disposed on the end of the valve body (1) toward the combustion chamber, and having at least one injection opening on the closing head (13) which originates at a pressure chamber (19) and whose outlet opening is covered by the valve body (1) in the closing position of the valve member (11) and is uncovered in the outward-oriented opening stroke.

Abstract: An injector body defines a fuel pressurization chamber, a spill passage, a stop volume and a nozzle outlet. Positioned within the injector body is a plunger which is movable between a retracted position and an advanced position. The plunger opens the spill passage to the fuel pressurization chamber over a portion of the distance between the retracted and advanced positions. The injector body also contains a needle valve member which includes a closing hydraulic surface that is exposed to fluid pressure in the stop volume. The stop volume is pressure coupled to the spill passage.

Abstract: A fuel injection event controller for a fuel injection nozzle includes a hydraulic lock device for selectively restricting the translatory opening of a fuel injection nozzle needle valve, the needle valve delivering a quantity of a fuel to a combustion chamber of an internal combustion engine. Methods of effecting rate shaping of the injection charge and of providing a two stage injection event are included.

Abstract: A hydraulically actuated fuel injector is disclosed having an injector body defining an actuation fluid inlet, an actuation fluid cavity, a nozzle outlet, and a needle control chamber. An actuator is attached to the injector body and a first valve member is disposed in the injector body and is moveable in response to the actuator between a first position in which the actuation fluid inlet is open to the actuation fluid cavity and a second position in which the actuation fluid inlet is closed to the actuation fluid cavity. A needle valve member is disposed in the injector body and is moveable between an open position in which the nozzle outlet is open and a closed position in which the nozzle outlet is blocked. The needle valve member has a closing hydraulic surface exposed to pressure in the needle control chamber.

Abstract: A fuel injection system includes a plurality of hydraulically actuated fuel injectors with direct control needle valves. Each injector has an injector body that defines an actuation fluid inlet, a fuel supply passage and a needle control chamber. A needle valve member is movably mounted in the injector body and has a closing hydraulic surface exposed to pressure in the needle control chamber. Each injector also includes a relatively slow moving actuation fluid control valve member and a relatively fast moving needle control valve member. A source of low pressure fluid is connected to the fuel supply passage, and a source of high pressure fluid is connected to the actuation fluid inlet.

Abstract: A pump controller (40) calculates a pump maximum absorbing horsepower and a pump required horsepower based on an accelerator signal, a pump delivery pressure and an operation signal, determines an engine required horsepower (PN) by selecting minimum one of both horsepower values, and calculates a pump required revolution speed based on the accelerator signal, the operation signal and an engine revolution speed signal to determine an engine required revolution speed (NN). The engine controller (40) determines, from the engine required horsepower (PN), a required-horsepower-referenced target engine revolution speed (NK) at which a fuel consumption rate is minimized, and selects larger one of the engine required revolution speed (NN) and the target engine revolution speed (NK) as an engine target revolution speed (NZ) to control an injected fuel amount and fuel injection timing, thereby controlling an engine torque and an engine output revolution speed.

Abstract: Pumps and injectors having a control valve with an adjustable stroke for rate shaping and associated methods for operating a control valve are provided. The pump or injector comprises a body with a pumping chamber and a control valve chamber. A plunger is disposed in the pumping chamber. An actuatable control valve disposed in the control valve chamber controls fuel. The control valve includes a valve body moveable over an adjustable stroke range including opened and closed positions. The stroke range is adjustable to vary an effective open gap when the valve body is in the open position. An actuatable valve stop assembly adjacent to the control valve chamber includes a main body and a stop member that is moveable between extended and retracted positions.

Abstract: A high-pressure pump for use in a fuel injection system for diesel engines is provided which includes a plunger slidably disposed within a chamber formed in a pump housing to define a pressure chamber whose volume is changed according to sliding movement of the plunger, a check valve disposed within a fluid inlet line extending from an inlet port to the pressure chamber, and a solenoid valve disposed within the fluid inlet line upstream of the check valve. The check valve establishes fluid communication between the inlet port and the pressure chamber during a fluid suction operation wherein the fluid is sucked into the pressure chamber, while blocking the fluid communication between the inlet port and the pressure chamber during a fluid feeding operation wherein the fluid sucked into the pressure chamber is pressurized and discharged from an outlet port. The solenoid valve controls a flow rate of the fluid sucked into the pressure chamber through the check valve.

Abstract: A fuel injector for periodically injecting fuel pulses of a variable quantity on a cycle to cycle basis as a function of the pressure of fuel supplied to the injector from a source of fuel and at a constant time during each cycle is set forth including an injector body containing a central bore and an injection orifice at the lower end of the body and a reciprocating plunger assembly including an upper plunger section and a lower plunger section serially mounted within the central bore to define a variable volume metering chamber located between the lower plunger section and the lower end of the injector body containing the injection orifice. The variable volume metering chamber communicates during a portion of each injector cycle with the source of fuel.

Abstract: A fuel injector comprises a valve needle biased by a spring towards a seating. The spring engages a spring abutment member which is moveable with a piston member. The spring abutment member defines, with a member carried by the needle, a damping chamber which communicates through a restricted passage with a low pressure drain to damp movement of the needle relative to the piston member.

Abstract: A method for apportioning a total fuel quantity to be injected to an engine by a hydraulically-actuated injector between a pilot shot and a main shot includes determining a pilot shot and/or main shot fuel quantity desired to be delivered during injection. The desired pilot shot fuel quantity is compared with a threshold pilot shot fuel quantity and/or the desired main shot fuel quantity is compared with a threshold main shot fuel quantity. The total fuel quantity is delivered by a pilot shot if the desired pilot shot fuel quantity is less than the threshold pilot shot fuel quantity and/or the desired main shot fuel quantity is less than the threshold main shot fuel quantity.

Abstract: This fuel injection device changes stepwise the effective opening area of the exhaust opening that releases the fuel pressure in the balance chamber, in order to control the lift velocity of the needle valve to give flexibility to the pattern of the initial fuel injection rate. The fuel injection device of this invention switches the current value applied to the solenoid between the large and the small value to change the distance traveled by the solenoid valve and thereby change the opening degree of the exhaust port that releases the fuel pressure in the balance chamber. Because the return spring mechanism having plural springs, the magnitudes of current necessary to be applied to the solenoid to move the solenoid valve are clearly differentiated. This reduces variations in the process of releasing the fuel pressure in the balance chamber, assuring a stable fuel injection rate control.

Abstract: A hydraulically actuated fuel injector includes an injector body having a nozzle chamber that opens to a nozzle outlet. A control valve is mounted in the injector body and is attached to a solenoid that is moveable between a rest position and a fully energized position. A piston/plunger/barrel assembly is utilized to hydraulically pressurize fuel in the nozzle chamber to a fuel pressure that is substantially proportional to an amount of current being supplied to the solenoid. A needle valve member is positioned in the nozzle chamber and moveable between an open position in which the nozzle outlet is opened and a closed position in which the nozzle outlet is blocked. Finally, a spring is utilized to bias the solenoid toward its rest position.

Abstract: The pump controller determines pump load torques (T.sub.r1, T.sub.r2) from tilting signals (.theta..sub.1, .theta..sub.2) of hydraulic pumps and delivery pressure signals ( P.sub.D1, P.sub.D2) of the hydraulic pumps based on T.sub.r1 =K.multidot..theta..sub.1 .multidot.P.sub.D1 and T.sub.r2 =K.multidot..theta..sub.2 .multidot.P.sub.D2 (K: constant), and adds these pump load torques to provide a resulting value as an engine load torque signal (T). Using the signal (T) and an engine revolution speed signal, an engine controller determines a fuel injecting rate to control a pre-stroke actuator. Simultaneously, the engine controller calculates target injection timing not to change fuel injection start timing, thereby controlling a timer actuator. This makes it possible to control the fuel injection rate with good response and high accuracy following load fluctuation, achieve improved combustion, and hold a fuel injection period within an optimum angle range.

Abstract: A diesel fuel injector is provided with a secondary spill aperture operable to increase to a maximum value and then decrease to zero during an early part of the injection portion of the stroke of the injector pump plunger in a manner to maintain injection pressure at relatively high levels at the beginning of such injection portion of the plunger stroke whereas the rate of injection is lower during such early part of such injection portion than it would be in the absence of said secondary spill aperture.

Abstract: The fuel injection pump does not generate an excessively large drive torque at the end of the fuel injection under the condition of the most advanced injection timing, even if a geometric injection rate (GIR) is raised to shorten an injection period. The fuel injection pump includes a sleeve (4), a plunger (1) movably received in the sleeve (4), a cam (2') for moving the plunger up and down in the longitudinal direction of the sleeve. The sleeve is shiftable relative to the plunger in the longitudinal direction of the plunger to delay or advance an injection timing and to use different portions of the cam from start (22) to end (23) of fuel injection. The cam (2') has a unique configuration to insure that when the sleeve is shifted downward and the fuel. injection timing is most advanced, the GIR drops from the start of the injection to the end.

Abstract: A system is provided for controlling a fuel-metering device, for a diesel engine. First means generate a first signal for triggering a first actuating means (115) for establishing the start of pump delivery and the end of delivery. Second means generate a second signal for triggering a second actuating means (125) for establishing the delivery rate. In this case, a signal characterizing the start of pump delivery is taken into consideration by the second means.

Abstract: A hydraulically-actuated fuel injector includes an injector body that defines an actuation fluid cavity, a piston bore, a plunger bore, a nozzle chamber and a nozzle outlet that opens to the nozzle chamber. A piston is slidably received in the piston bore and moveable between an upper position and a lower position. A plunger is slidably positioned in the plunger bore and moveable between a retracted position and an advanced position. A portion of the plunger and the plunger bore define a fuel pressurization chamber that opens to the nozzle chamber. The injector body further defines a nozzle supply passage extending between the fuel pressurization chamber and the nozzle chamber, a spill passage extending between the nozzle supply passage and the nozzle chamber, and a fuel return passage opening into the nozzle chamber.

Abstract: A hydraulically actuated fuel injector includes an injector body having an actuation fluid inlet and a needle control chamber. A hydraulic means within the injector pressurizes fuel in the injector body. The hydraulic means includes an actuation fluid control valve having a solenoid and is movable to open and close the actuation fluid inlet. A needle valve member includes a closing hydraulic surface exposed to pressure in the needle control chamber. A needle control valve, which utilizes the same solenoid, is mounted in the injector body and movable to open and close the needle control chamber to a source of high pressure fluid. The slower response time of the actuation fluid control valve allows for direct control of the fast responding needle valve by a single fast acting solenoid.

Abstract: In accordance with preferred embodiments of the invention a timing adjustment device includes a cam follower that is engaged between an overhead cam and an injector rocker arm, and is mounted on a rotatable eccentric shaft. The geometry of the eccentric shaft and cam follower is designed so that, as timing is varied by rotation of the eccentric shaft, no change is produced in the vertical height of the rocker arm when the cam shaft is on the outer base circle and the injector is bottomed, in order to assure that the "mechanical crush" of the PT type injector is constant despite changes in timing. In a first application of the timing arrangement, it is used together with a simple injector, which does not utilize a multi-plunger arrangement to form a hydraulic link, to achieve lower parasitic losses.

Abstract: This accumulating fuel injection apparatus is provided with a needle valve 6 adapted to open and close an injection nozzle 11 having injection ports 14 in a lower end portion thereof, a balancing chamber 5 formed in a casing 2 so as to apply a fuel pressure to a head portion of the needle valve 6, a supply passage including a slit 10 and used for supplying a fuel from a fuel supply port 19 to the balancing chamber 5, a discharge passage 20 comprising an orifice for discharging the fuel from the balancing chamber 5, and a solenoid valve 22 adapted to open and close the discharge passage 20, the lift of a valve disc 26 of the solenoid valve 22 is controlled by a lift control means comprising a stopper 28 the position of which is controlled by a lift control mechanism 23.

Abstract: A fuel injection valve (1; 2) for the intermittent injection of fuel into the combustion chamber of an internal combustion engine is equipped with a hydraulic control device (15; 100). The opening or closing of a control bore (61; 109) is brought about by means of an electrically controlled solenoid valve (5; 6; 7), with the result that a control pressure in a control chamber (60; 114) is influenced, thus causing the opening or closing of injection ports into the combustion chamber via a control piston (30; 110) and an injection-valve member (24). The injection event is controlled additionally by controlling the movement of a solenoid-valve pilot-valve stem (70; 125) assigned to the control bore (61; 109). Means, by which the opening movement of the injection valve member (24) takes place in two successive phases, are provided.

Abstract: An improved hydraulically-actuated fluid injector system comprises a hydraulically-actuated fuel pressurization member, a fluid storage chamber, and a direct-operated check. Pressurization of fluid in the storage chamber begins before the start of fluid injection. Fluid injection begins by hydraulically unbalancing the check. Fluid injection ends by hydraulically balancing the check to allow a biasing device to close the check. Preferably, actuating fluid that is spilled from the fuel pressurization member (to end fuel injection) is communicated to a hydraulic motor which drives a source of pressurized hydraulically-actuating fluid.The present invention provides improved control of several fluid injection parameters, including higher peak fluid injection capability and less fluid injection pressure drop at the end of injection, resulting in improved engine performance and lower emissions, noise, and wear.

Abstract: According to the present invention, a fuel injection apparatus includes a casing having a control pressure chamber for storing fuel supplied from fuel passage, a needle valve to which fuel stored in the control pressure chamber applies pressure in the valve closing direction, a valve device for interrupting communication between the fuel passage and the control pressure chamber to seal fuel in said control pressure chamber, and volume changing device for expanding volume of the control pressure chamber after fuel is sealed in the control pressure chamber by the valve device. According to the above fuel injection device, pressure in the control pressure chamber is reduced while the fuel is stored therein by the volume changing device, the nozzle needle is lifted, and injection is started. For this reason, it is not necessary to supply surplus fuel in addition to the injection fuel during the fuel injection.

Abstract: In hydraulically actuated fuel injectors, an intensifier piston is utilized with a plunger for raising fuel pressure to initiate an injection event with a VOP type fuel injector. The present invention lowers the mass flow rate of fuel at the beginning of each injection event by slowing the rate of the plunger relative to the intensifier piston by utilizing a spring to separate the two. As the spring compresses, energy from the high pressure actuation fluid is absorbed rather than transferred to raise fuel pressure. A short time into each injection event, the spring becomes fully compressed and the intensifier piston and plunger begin moving in rigid unison for the remaining of the injection event in a manner typical of prior art fuel injectors. The lowering of injection mass flow rate toward the beginning of each injection event results in improved engine performance and a lowering of undesirable exhaust emissions, especially NOx compounds.

Abstract: A fuel injection system for diesel engines provides precision metering of the amount of fuel admitted to each cylinder under very high pressure throughout the speed and load range.

Abstract: A fuel injection device for internal combustion engines comprises a unit injector for each cylinder and a rocker arm driving the pump piston of each injector, the rocker arm consisting of a rigid portion and a spring portion mounted under tension to the rigid portion, the spring portion deflecting at a predetermined load to limit the increasing pressure as the injection volume increases.

Abstract: A fuel injection rate shaping control system is provided which effectively controls the flow rate of fuel injected into the combustion chamber of an engine to improve combustion and reduce emissions by controlling the rate of pressure increase during injection. The injection rate shaping control system includes a rate shaping control device including a rate shaping transfer passage having a predetermined length and diameter specifically designed to create a desired injection pressure rate shape. In other embodiments of the present invention, two or more rate shaping transfer passages capable of producing distinct rate shapes are packaged in various fuel injection systems to selectively provide various rate shapes depending on operating conditions. Switching valves, i.e., solenoid operated three-way valves, may be used to direct the fuel or timing fluid flow to any one of the rate shaping transfer passages.

Abstract: A control method for starting a diesel engine makes it possible to prevent an excessive increase in fuel injection rate in a low speed rotation range at the time of starting for prevention of occurrence of misfiring and unstable engine rotation, and to prevent occurrence of black smoke by controlling the injection rate according to the engine temperature. For this effect, from the beginning of engine starting to a first engine rotating speed (N.sub.1), the control rack is moved in the fuel injection rate reducing direction so that the rack position has a first gradient to correct for an increase in fuel injection rate and, from the first engine rotating speed to a second engine rotating speed (N.sub.3) at which the control rack is returned to its position for ordinary control, the control rack is moved in the fuel injection rate reducing direction so that the rack position has a second gradient greater than the first gradient.

Abstract: A compensator scheme is described to compensate variable pressure gasoline injection systems, used on four stroke cycle gasoline engines, for variations of engine speed and intake manifold pressure. The intake manifold pressure compensator adjusts the compression ratio of the gas pressure cycling means of the variable pressure injection system. The engine speed compensator adjusts the ratio of liquid injection pressure to gas pressure in the gas pressure cycling means. Both compensators can be corrected by use of feedback from an engine exhaust gas composition sensor.

Abstract: A pilot injection controller and a method of controlling pilot injection quantity enable the quantity of fuel pilot-injected fuel by an internal combustion engine fuel injection system of the type in which the fuel delivery stroke for pilot injection is fixed to be maintained substantially constant irrespective of engine speed by controlling prestroke such that the utilized portion of a cam is shifted to a lower delivery velocity region thereof with increasing engine speed, the principle involved being that the quantity of fuel pilot-injected by a fuel injection system is proportional to the actual plunger delivery velocity and the fact that since the actual delivery velocity is proportional to the product of the cam velocity constant and the cam rotational speed the actual delivery velocity can be maintained substantially constant by increasing the cam velocity constant in the low speed region and decreasing the cam velocity constant in the high speed region.

Abstract: A nozzle is provided wherein the operation of injection hole groups is switched from one to another in accordance with the axial displacement of a spool valve. A nozzle body has a bottomed hole, and a plurality of injection hole groups are provided at different circumferential levels in the side wall of the bottomed hole, the injection holes at different circumferential levels being different in diameter from each other. The valve portion of the spool valve is urged by a spring so that the lower end of the valve portion abuts against the base of the bottomed hole in the normal condition. Moreover, a fuel passage communicates with one of the injection hole groups in the normal condition and communicates with the other injection hole group at a position where the valve portion is displaced axially against the spring force on receiving the pressure of pressurized fuel.

Abstract: A multipiece fuel pump plunger assembly for controlling the fuel injection rate and delivery during the initial injection portion of a fuel injection cycle for an internal combustion engine. The injector includes a two piece plunger assembly including a plunger and a plunger sleeve. The plunger having a small predetermined diameter and being slidably positioned within a plunger sleeve having a diameter greater than the diameter of the plunger. The multipiece plunger is advantageous because it allows for shaping of the rate of fuel injected into the combustion process thereby reducing the excess fuel flow in the early portion of the injection cycle. Elimination of the excess fuel flow results in lower oxides of nitrogen and particulate exhaust emission levels and less engine noise.

Abstract: An improved electronically-controlled fluid injector system comprises a fluid storage chamber and a direct-operated check. Pressurization of fluid in the storage chamber begins before the start of fluid injection. Fluid injection begins by hydraulically unbalancing the check. Fluid injection sharply ends by hydraulically balancing the check to allow a biasing device to close the check.The present invention provides improved control of several fluid injection parameters, including higher peak fluid injection capability and less fluid injection pressure drop at the end of injection, resulting in improved engine performance and lower emissions, noise, and wear.

Abstract: In one aspect of the present invention, a method is disclosed for controlling the fuel injection rate of a hydraulically-actuated fuel injector. A desired actuating fluid pressure is determined based on the engine speed and temperature. The desired actuating fluid pressure is used to control the fuel injection rate to result in quick engine starting.

Abstract: An injection system provides an intermittent supply of fuel mixture into combustion spaces of an internal-combustion engine. The system includes a valve and a pipe by way of which a control space in the injection valves may alternatively be acted upon by a pressure. The control space is formed by a valve member and a piston. A first pressure spring presses the valve member onto an injection opening, and a second pressure spring presses the piston away from the injection opening.

Abstract: A unit fuel injector adapted to receive fuel from a fuel supply at relatively low pressure and adapted to inject fuel at relatively high pressure into the combustion chamber of an internal combustion engine is provided, comprising an injector body having a first internal bore and an injector orifice and a plunger mounted for reciprocating movement within the first internal bore to define a variable volume fuel pressurization chamber including a cam actuated upper plunger portion and a lower plunger portion mounted in the first internal bore between the variable volume fuel pressurization chamber and the upper plunger portion. While the upper plunger portion is in its retracted position, low pressure fuel from the fuel supply is supplied to the variable volume fuel pressurization chamber.