Abstract: A preferred embodiment EGR valve permits exhaust gas to be induced into the intake line downstream of the compressor, while minimizing the need to reduce the size of the turbocharger. The preferred embodiment EGR valve exploits variations around the mean pressure in the EGR passage created by the engine cycle by selectively opening when the pressure in the EGR valve exceeds the pressure in the intake line. Thus, exhaust gas is recirculated even when the engine is running near torque peak. The preferred embodiment EGR valve also exploits the higher mean pressure in the exhaust line relative to the intake line at higher engine speeds by remaining open, in order to minimize the energy consumed in opening and closing the EGR valve.

Abstract: An improved closed nozzle injector assembly for injecting high pressure fuel into the combustion chamber of an engine is provided which includes a first needle valve element associated with a first set of injector orifices, a first needle valve control device for controlling the opening and closing of the first needle valve, a second needle valve associated with a second set of injector orifices and a second needle valve control device for controlling the opening and closing of the second needle valve. Each needle valve control device includes a control volume positioned at one end of the respective needle valve, a control volume charge circuit for supplying high pressure fuel to the respective control volume and the respective injection control valve for controlling the flow of high pressure fuel from the respective control volume to a low pressure drain thereby controlling the movement of the respective needle valve.

Abstract: An improved closed nozzle injector assembly for injecting high pressure fuel into the combustion chamber of an engine is provided which includes a first needle valve element associated with a first set of injector orifices, a first needle valve control device for controlling the opening and closing of the first needle valve, a second needle valve associated with a second set of injector orifices and a second needle valve control device for controlling the opening and closing of the second needle valve. Each needle valve control device includes a control volume positioned at one end of the respective needle valve, a control volume charge circuit for supplying high pressure fuel to the respective control volume and the respective injection control valve for controlling the flow of high pressure fuel from the respective control volume to a low pressure drain thereby controlling the movement of the respective needle valve.

Abstract: A unitized fuel supply assembly is disclosed including an in-line reciprocating cam driven pump (14) for supplying fuel to an accumulator (12) from which fuel is directed to a plurality of engine cylinders by means of a distributor (16) mounted on the unitized assembly. Dual pump control valves (20) provide fail safe electronic control over the effective pump displacement. One or more injection control valves mounted on the distributor are provided to control injection timing and quantity. The accumulator (12) contains a labyrinth of interconnected chambers (36) which are shaped and positioned to produce a minimum overall package size while providing for easy manufacture.

Abstract: An improved fuel injector for providing precise control over injection timing, quantity and rate shape is provided which includes a fuel pressure balancing device for balancing the fuel pressure forces acting on a needle valve element while the element is in both the closed and open positions thereby permitting an actuator to more precisely and predictably control the movement of the needle valve element. The fuel pressure balancing device includes a cavity formed in the needle valve element and pressure balancing surfaces formed on the needle valve element and positioned in the cavity. The actuator may be a piezoelectric actuator for compressing actuating fluid in an actuating fluid circuit which includes a fluid chamber positioned adjacent a needle valve element and fluidically separate from a fuel supply circuit for supplying high pressure fuel for injection. Actuating fluid pressure in the chamber acts on the needle valve element to initiate injection.

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 assembly is provided which operates to effectively creating a low injection flow rate followed by a high injection flow rate during all engine operating conditions, including idle and low engine speed conditions, to produce a high quality fuel spray with proper atomization and thus improved fuel air mixing resulting in improved emissions abatement and fuel economy. The assembly includes two biased valve elements designed to sequentially open and close to initially open a limited number of orifices followed by the opening of a remainder of the orifices thereby effectively varying the available cross sectional flow area from the nozzle cavity into the combustion chamber of the engine during the injection event. The nozzle valve elements may be spring biased or fluid pressure biased and include biasing surfaces sized to cause the sequential opening and closing of the elements.

Abstract: An injection rate shaping nozzle assembly for a fuel injector is provided which includes a closed nozzle valve element and a rate shaping control device including an injection spill circuit for spilling a portion of the fuel to be injected to produce a predetermined time varying change in the flow rate of fuel injected into a combustion chamber. The spill circuit includes a spill passage integrally formed in the nozzle valve element. The rate shaping control device may include a spill accelerating chamber in formed in the nozzle valve element for creating a rapid increase in the spill flow rate. A spill circuit purge device is provided to remove fuel from the spill circuit and accelerating chamber between each of the injection events thereby ensuring an unimpeded, effective spill fuel flow during the next spill event.

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: 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 cam operated open nozzle fuel injector is provided comprising a reciprocating plunger assembly including an outer plunger, an inner plunger and a variable volume timing chamber located between the plungers. A hold down force generating means includes a cam having a hold down cam or ramp portion for maintaining the inner plunger in an innermost position against the inner end of the injector body with a sufficient hold down force during each hold down period throughout injector operation independently of injector train wear. The hold down cam portion operates to move the outer plunger inwardly towards the inner plunger throughout a substantial portion of the hold down period. The hold down cam portion functions to compensate for fuel drainage from the timing chamber so as to maintain a predetermined pressure in the timing chamber corresponding to a desired hold down force.

Abstract: A solenoid valve for use in a fuel system includes a valve body with a central core and three interconnected passageways. A spool is disposed within the central core and by means of enlarged and reduced diameter portions controls the flow through the solenoid valve. Solenoid armatures cooperatively control movement of the valve spool which is sized and shaped so as to provide a fuel flow path from an inlet passageway to an outlet passageway when the solenoid valve is in an opened condition. When the spool is shifted to a closed condition, incoming fuel is blocked and a flow path is created from the output passageway to a drain passageway, The drain passageway allows excess fuel in the injector to drain to relieve fuel pressure on the metering plunger. As the spool moves from a closed condition to an opened condition, some fuel flows to the drain passageway. The amount of fuel "loss" depends on the speed of the spool and the size of the drain passageway.

Abstract: An open nozzle unit fuel injector having an injector body for receiving a plunger assembly therein is disclosed including a fuel supply source for providing a metered quantity of fuel to a metering chamber formed in a central bore of the injector body to be injected into the cylinder of the internal combustion engine and a trapped volume spill port for a volume of fuel trapped in the metering chamber when the plunger has moved from its fully retracted position to its fully advanced position and injection has terminated. In accordance with the present invention, an open nozzle unit fuel injector is achieved which exhibits a sharp ending of injection, which prevents secondary injection and which significantly reduces the unburned hydrocarbon emissions of the engine incorporating such open nozzle unit fuel injectors including a trapped volume spill port.

Abstract: A metering system is provided which controls the amount of fuel supplied to the combustion chambers of a multi-cylinder internal combustion engine comprising a fuel pump for supplying fuel at low pressure to a first and a second group of unit fuel injectors, a first solenoid-operated fuel control valve controlling the flow of fuel to the first set of injectors and a second solenoid-operated fuel control valve controlling the flow of fuel to the second set of injectors. The system may also include first and second solenoid-operated timing fluid control valves associated with the first and the second group of injectors, respectively. The injectors are capable of being in the fuel receiving mode, establishing a metering period, and the timing receiving mode, establishing a timing period, at the same time to increase the amount of time available for metering both timing fluid and fuel.

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 variable displacement high pressure pump having a plurality of high pressure pumping units which receive fuel from a low pressure fuel pump. A rotary cam-driven roller tappet, for producing pumping displacement of the pumping plunger of a respective pumping element, is connected to the pumping plunger by a separated link in a manner permitting the pumping plunger to float relative to the roller tappet during at least a portion of each pumping cycle. As a result, the capacity of the pumping chamber can be limited to an extent that is less than the full stroke achievable by the pumping plunger being retracted to the maximum extent which is permitted by the driving cam.

Abstract: A fuel distributor is provided which is capable of distributing fuel through plural fuel injection lines to the corresponding cylinders of a multicylinder internal combustion engine and which includes a distributor housing including a supply inlet passage, a plurality of fuel injection outlet passages and a plurality of distributor valves for providing sequential periodic fluidic communication between the supply inlet passage and the outlet passages. Each distributor valve, which may be cam-actuated or solenoid-actuated, is adapted to be placed in an open position to define a fuel injection period during which high pressure fuel may flow through the distributor valve to the respective engine cylinder and a closed position blocking fuel flow through the respective fuel injection outlet passage.

Abstract: In accordance with preferred embodiments, a fuel injector has a gas accumulator of a volume that is at least ten times the maximum amount of fuel which would have to be injectable thereby, and a solenoid operated poppet valve with an end face that opens into the combustion cylinder and is shaped to deflect a portion of the fuel injected into direct contact with the ignition plug. In a first embodiment, using a variable fuel supply, an electronic control unit (ECU) controls the injection timing to inject the compressed gas into the cylinders as each's piston nears its top dead center (TDC) position to obtain diesel engine-like efficiencies (.eta.=45%) so long as the compressed gas supply pressure is sufficiently high (at least approximately 2,000 psi), and when the compressed gas supply pressure becomes too low for high efficiency operation (i.e.

Abstract: A unit fuel injector is provided comprising an injector body containing a pumping chamber and a valve element provided for movement between (i) an advanced position wherein a supply passage communicates with the pumping chamber through a 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. In one embodiment the valve element includes a control valve integrally formed with a tip valve, and a force balancing element for tending to balance the forces acting on the valve element by reducing the effective cross-sectional area upon which fluid pressure operates. The control valve, whether formed integral with or separate from the tip valve, extends through the solenoid to engage a valve seat formed adjacent the pumping chamber.

Abstract: A unit fuel injector assembly (88) periodically injects fuel 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 variable time during each cycle as a function of the pressure of the timing fluid supplied to the injector from a source of timing fluid. A reciprocating plunger assembly (146) is received within the injector body (106) and includes an upper plunger section (148), a lower plunger section (150) and an intermediate plunger section (152) in order to define a variable volume timing chamber (138), a variable volume injection chamber (162) and a variable volume compensation chamber (176).