Abstract: The valve comprises a shutter for the drain conduit of the control chamber of 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 and, hence, the hydraulic resistance and mass of the armature.

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.

Abstract: A pump comprising a number of radial cylinders arranged a given angular distance apart about a drive shaft and each housing including a piston resting radially on a respective pad by virtue of the action of a return spring. The connection between the piston and pad comprises a retainer for preventing in-service detachment of the pad, which rests on a respective flat portion of a cam mounted for rotation on an eccentric portion of the shaft. The force on the pad produced by sliding friction between the pad and the flat portion of the cam and directed perpendicular to the axis of the cylinder is absorbed by the piston.

Abstract: The valve comprises a shutter for the drain conduit of the control chamber of the injector; and an electromagnet having a fixed core, and an armature controlling the shutter and which is normally pushed by a return spring for maintaining the drain conduit closed by the shutter.The device for adjusting the travel of the armature comprises a plate which is fitted to the body of the injector by means of a sleeve and via the interposition of two sets of calibrated washers. The plate presents a stop element against which is arrested a contact element integral with the armature, for preventing the armature from contacting the core.

Abstract: A pump having a number of radial cylinders each housing a sliding piston. Each cylinder is closed by a respective head, and comprises an intake valve and a delivery valve having respective seats inside a plate. The intake valve is located at the end of an intake channel having a first portion through the plate, a second portion formed between the head and the plate and perpendicular to the axis of the cylinder, and a third portion parallel to the cylinder axis. The delivery valve presents a truncated-cone-shaped seal communicating with the pumping chamber via a conduit also extending through the plate; and the two plungers are made of ceramic and guided by a respective retainer.

Abstract: A pumping apparatus is disclosed comprising a tank containing a fluid to be umped, a main pumping stage for pumping a controlled amount of said fluid at a predetermined pressure, a supply pump for supplying fluid from said tank to said main pumping stage in excess to said controlled amount, and feedback means for feeding the excess fluid back to said tank along a given drain path; wherein the improvement includes at least part of said drain path running in regions of said main pumping stage subjected to severe thermal and/or mechanical stress.

Abstract: The body of a control valve is housed inside the hollow body of an injector y means of a fluidtight connection comprising a pair of precision ground mating surfaces, and a sealing ring compressed between a further two surfaces of the bodies adjacent to the aforementioned pair of surfaces. The ring may be made of rubber, may be fitted between two cylindrical surfaces, and is also pressed by the fuel on to a shoulder of the valve body. Alternatively, the ring may consist of a soft iron washer pressed axially between a flange on the valve body and a surface of the hollow body.

Abstract: The control valve of an injector comprises a plunger and a valve body having an axial control chamber connected to a drain conduit via a hole. The hole terminates at a flat surface of the valve body, which surface is perpendicular to the operating direction of the actuator of the plunger. The plunger consists of a pad element having a flat face engaging the surface of the valve body, while the opposite face may be flat or spherical, and is engaged by a complementary surface on the end of the actuator.

Abstract: An electromagnet housed in a skirt pressed on to a cap integral with the in conduit of the control valve. The skirt presents two shoulders separated by a distance greater than the height of the core of the electromagnet and on which the core and the cap rest. At least one Belleville washer between the core and the cap holds the core elastically on the respective shoulder and detached from the cap. A retaining ring coaxial with the washer is also provided for sealing the fuel flowing in an axial hole on the core and in the drain conduit.

Abstract: A control valve for an injector comprising a valve body having of a control chamber connected to a drain conduit via a hole terminating at a flat surface of the valve body. The plunger of the valve consists of a plate housed in a seat, the bottom wall of which arrests the travel of the plate after a travel "b". This is controlled by the armature of an electromagnet, which armature presents a rod arrested directly by an adjustable stop after traveling a distance "a" greater than travel "b". The opening and closing time of the valve is therefore unaffected by wear on the stop of the armature. The rod of the armature is in one piece with a stem activating the plate, and with a threaded portion screwed to the armature.