Abstract: The metering valve has a shutter for a discharge conduit, and an electromagnet for controlling an armature disconnected from the respective stem and sliding along the stem by means of a sleeve. The stem is guided by a fixed sleeve and is pushed by a first spring to hold the shutter in the closed position, and a second spring keeps a shoulder of the armature resting axially against a C-shaped ring fitted to the stem. To reduce the overtravel of the armature with respect to the travel of the stem to move the shutter into the closed position, and to damp oscillation of the armature, provision is made, between the two sleeves, for a bush of calibrated thickness, which slides along the stem and is such as to form a small axial clearance with the sleeves.

Abstract: The injector has a hollow body having an injection nozzle controlled by a ntrol rod movable axially by a metering valve controlled by an armature of an electromagnet. The metering valve has a control chamber having a pressurized-fuel inlet conduit and a surplus fuel drain conduit. To reduce the length of the injector, the inlet conduit is coaxial with the rod and communicates with a coaxial cavity fed with fuel from the top; the drain conduit is radial with respect to the axis of the rod, and the armature is also movable radially; the armature and the electromagnet are housed in an arm which is also radial with respect to the axis of the rod; and the cavity has a conical portion in which a bulb-shaped portion of a fitting of a supply conduit is fitted by means of a ring nut.

Abstract: The metering valve is fitted in a hollow body of the injector and is contled by the armature of an electromagnet. The travel of the armature towards the electromagnet is arrested by a stop element fittable to the hollow body by a threaded element, which is screwed to a thread of the hollow body with a calibrated tightening torque to adjust the travel of the armature towards the electromagnet according to of the tightening torque. The method of adjustment includes the steps of fitting the stop element in the hollow body by a threaded element, and applying a calibrated tightening torque to the threaded element.

Abstract: The metering valve is controlled by the armature of an electromagnet; the avel of the armature towards the electromagnet is arrested by a stop member integral with a flange fitted to a hollow body by a ring nut connecting the skirt of the electromagnet; a spacer washer made of elastically compressible material is provided between the flange and a shoulder of the hollow body; and the tightening torque of the ring nut compresses the washer accordingly to adjust the travel of the armature. According to a variation, a washer of rigid material is provided between the flange and the shoulder, and is small in width to form a projecting annular portion of the flange, which portion of the flange is flexed accordingly by the tightening torque of the ring nut.

Abstract: An on-off valve is connected between a high-pressure pump and a low-press pump and is sized to be rapidly activated during the cranking stage of an internal combustion engine. After actuating the on-off valve, surplus fuel is drained into an inner chamber of the high pressure pump. A solenoid valve is further provided between the low-pressure pump and the on-off valve to automatically cut off the supply of fuel to the on-off valve in the event of an engine failure. The apparatus is beneficial to reduce variation in the fuel supply of the low pressure pump during engine start-up and steady-state operation.

Abstract: A torque-dividing transmission, particularly for aircraft, having a single nput pinion and a single output gear, both rotating about respective fixed axes; at least two gear assemblies, both interposed between the pinion and the output gear, and each for transferring a respective portion of the torque from the pinion to the output gear; and a torque-dividing device for dividing the input torque equally between the two gear assemblies; the torque-dividing device having, for each gear assembly, a number of elongated elements elastically bendable in use.

Abstract: The injector has a hollow body carrying a nozzle, and a metering valve hag a valve body housed in a cylindrical seat of the hollow body. The valve body has a distribution cavity for distributing high-pressure fuel to a control chamber of the valve, whereas the seat communicates with a cavity at atmospheric pressure and in which the control rod slides. The sealing device has an annular seal, which is compressed between two shoulders carried by the surface of the seat and by an outer surface of a portion of the valve body so as to provide for redundant sealing between the two surfaces.

Abstract: The injector has a hollow body supporting a nozzle, and a metering valve ing a valve body housed in a cylindrical seat of the hollow body; the valve body has an annular cavity for distributing high-pressure fuel to a control chamber of the valve; the seat communicates with an axial cavity of the hollow body, in which the control rod slides and which is at atmospheric pressure; the valve body is fitted to the hollow body by means of a ring nut; the valve body has a portion having an outer truncated-cone-shaped surface; the seat has a portion having an inner truncated-cone-shaped surface; and the two truncated-cone-shaped surfaces have the same taper, and engage mutually in fluidtight manner by virtue of the ring nut.

Abstract: The metering valve has a ball shutter for a conical seat over a discharge nduit, and an electromagnet for controlling an armature; a stem of the armature has a flange, is guided by a fixed sleeve, and is pushed by a spring to keep the ball in contact with the conical seat; provision is made, between the flange and the ball, for a decoupling joint in the form of a plate having a flat surface engaging the flange and a spherical concavity engaging the ball to center the ball on the conical seat; and the diameter of the concavity is slightly larger than the diameter of the ball to reduce the pressure between the mutually engaging surfaces of the concavity and the ball.

Abstract: The pump has a number of cylinders arranged with their respective axes at a predetermined angular distance about a drive shaft; and a number of piss, each sliding inside a respective cylinder. The inner radial end of each piston is fitted with a pad engaging a respective flat portion of a cam rotating on an eccentric portion of the drive shaft; and, to ensure against seizure, each pad has a cavity inside which is fitted a shoe having at least one layer of self-lubricating material engaging the respective flat portion of the cam.

Abstract: The injector has a recirculating conduit with an end element having two rsses, each incorporating an opening; the backflow connector has a connecting element having a groove, and is fitted to the end element so that the groove corresponds with the openings; a C-shaped snap-on fastener has two arms with two portions for simultaneously engaging or releasing the recesses and, via the openings, also the groove; and the backflow connector is connected and disconnected by translating the fastener, which, however, remains secured to the injector at all times.

Abstract: The injector has a hollow body supporting a nozzle, and a metering valve ing a valve body housed in a cylindrical seat in the hollow body; the valve body has a guide seat for a rod controlling the pin of the nozzle; the guide seat terminates with an end surface against which a stop portion of the rod is arrested; the stop portion has a truncated-cone-shaped surface which engages a truncated-cone-shaped portion of the end surface of the guide seat; and the truncated-cone-shaped portion is adjacent to the control chamber and has the same taper as the truncated-cone-shaped surface.

Abstract: A metering valve presenting a shutter for a discharge conduit, and an eleomagnet in turn presenting a fixed core and a disk-shaped armature detached from and sliding on the stem by means of a sleeve. The stem is guided by a bush, presents a flange movable inside a swirl chamber with a velocity damping effect, and is fitted, prior to assembling the armature and the electromagnet, by means of a ring nut, which presses a flange, forming one piece with the bush, against the body of the valve via the interposition of calibrated washers so selected as to define the travel of the stem.

Abstract: The metering valve has a shutter for a discharge conduit, and an electromet for controlling an armature disconnected from a respective stem and sliding along the stem by means of a respective sleeve; the stem is guided by a bush and pushed by a first spring to keep the shutter in the closed position; and the armature is held axially resting against the stem by a second spring preloaded between the armature and an annular shoulder of the stem, so as not to affect the action of the first spring.

Abstract: A metering valve has a valve body with a control chamber, a pressurized f supply conduit and a fuel drain conduit. A control rod of a shutter includes an element for hydraulically affecting the fuel supply conduit and the fuel drain conduit so that fuel drainage is considerably reduced. The control rod slides in a first cylindrical portion of the control chamber. A second portion of the control chamber that is coaxial with the first portion forms an annular shoulder against which the element is arrested. The fuel supply conduit is located radially of the first portion, and the fuel drain conduit is located axially of the second portion of the control chamber.

Abstract: A shutter in the form of a needle is controlled by a rod in turn controlled y an electromagnetic metering valve and which acts on the needle via a cylindrical plate formed in classes differing in terms of height. The plate for fitment between the rod and the needle is selected from the class corresponding to the travel of the needle required to open one or more orifices in the nozzle; and, to absorb any transverse components of the forces exchanged between the rod and needle and so prevent wear of the contacting surfaces of the needle and nozzle, the plate is guided inside the injector body with a very small clearance, e.g. in the region of 0.02 mm.

Abstract: The metering valve is controlled by an electromagnet having a fixed core, a oil, and an armature. The core is formed by pressing and subsequently sintering a mixture of powdered ferrous material and an epoxy binder; and presents a low magnetic hysteresis and low parasitic currents, so that, for a given energizing current, a greater magnetic force is achieved and more rapidly, and, for a given magnetic force or maximum operating frequency, the core and/or coil may be made smaller.

Abstract: A device presenting a high-pressure pump, and a low-pressure pump connected pstream from the first. To prevent damage in the event of a fault on the device, the connection between the low- and high-pressure pumps is provided with a cutoff valve which is closed in the event of a fault on the low-pressure pump to prevent the intake of solid particles by the high-pressure pump. Also, in the event of a fault on one of the injectors, detected on the basis of the operating conditions of the engine, the low-pressure pump is disconnected to prevent seriously damaging the engine.

Abstract: A control circuit for supplying a load with current having a high-amplitude ortion with a rapid leading edge, and a lower-amplitude portion. The circuit is input-connected to a low-voltage supply source, and comprises a number of actuator circuits parallel-connected between the input terminals and each including a capacitor and a load. Each actuator circuit also comprises a first controlled switch between the respective load and a reference line, for enabling energy supply and storage by the respective load. A second controlled switch is provided between the capacitor line and the load line, for rapidly discharging the capacitors into the load selected by the first switch and recirculating the load current, or for charging the capacitors with the recirculated load current.

Abstract: The valve comprises a shutter for the drain conduit of the control chamber f the injector; and an electromagnet having a fixed core with a seat for a coil which is energized to operate the armature controlling the shutter. The core presents two coaxial annular pole pieces, the outer one of which is shorter than the inner one and fitted with a ring of magnetic material partially closing the seat and enabling a substantial reduction in the diameter of the armature. The smaller diameter of the armature enables it to be fitted to the body of the injector by means of a larger-diameter threaded ring nut. The armature, together with a return spring, is fitted to a plate having a sleeve for guiding the stem; and the assembly is then fitted to the body independently of the electromagnet by screwing the ring nut inside a seat in the body.