Abstract: The portion of the profile of an asymmetric cam which controls the closure of a valve in an internal combustion engine is steep enough to ensure that, when the engine speed exceeds a threshold value, the valve closes, without contact between the valve and the cam , within a period of time which is substantially fixed as the engine speed varies, so that the angle of the cam upon closure increases with increases in the rate of rotation of the cam. The active surface of a bucket-type tappet interposed between the cam and the valve has a flat portion substantially perpendicular to the line of movement of the tappet and a curved portion which is connected to the flat portion and has a uniform radius of curvature so as to have a convex region facing the cam.

Abstract: An electromagnetically-controlled fuel injection valve (1) for i.c. engines includes a body (2) carrying an upper electromagnetic metering valve (10) which controls communication between a control chamber (9), to which the fuel is fed under pressure through an inlet hole (Z) to keep the associated injector needle (4) in the closed position, and a discharge hole (A) for controlling the opening of the needle (4). The solenoid valve (10) with the control chamber (9), the inlet hole (Z) and the discharge hole (A) are integrated in a single element forming a head (13) for the body (2) of the injection valve (1).

Abstract: A pump with a body formed by two elements sealingly clamped together, between which is defined a central chamber in which a drive shaft carrying an eccentric is rotatably mounted. A plurality of cylinders which open into the central chamber are arranged radially around the shaft in one element of the body, and pistons which cooperate with the eccentric are slidably mounted therein. These cylinders are in communication with a supply chamber defined between the first and second elements. The supply chamber is annular in shape and is formed in a position radially outside the central chamber. At least one sealing member separates the supply chamber from the central chamber. At least one passage is formed in one of the elements to put the supply chamber into communication with the central chamber. An electrically-controlled device controls the flow of fluid through the passage in a predetermined manner.

Abstract: An injection pump for fuel injection systems with controlled injectors for diesel engines, including at least one cylinder-and-piston pumping unit driven by a shaft with eccentrics and connected through an intake valve and a delivery valve to inlet and outlet means for the fuel. A solenoid pressure-regulating valve fitted directly to the body of the pump is interposed between the delivery means and the injectors.

Abstract: Fuel injection apparatus for diesel engines includes an injection pump connected to an injector nozzle through a control device constituted by two calibrated and opposed non-return valves arranged to keep a residual pressure of a predetermined magnitude in the fuel supply passage to the injector between each injection cycle and the next. The two non-return valves are located downstream of the output of the pump and are preferably inserted in a body fixed to or forming part of the injector, or forming part of the delivery union of the pump.

Abstract: A fuel injection pump for diesel engines, in which the pressure chamber of each cylinder (10) is defined on its side opposite the piston (16) by a slide valve (38) movable in a direction opposite the piston against the action of resilient biasing means (52). The slide valve is sensitive to the supply pressure of the fuel and controls communication between the pressure chamber and the fuel delivery passage (44, 46). The supply pressure is controlled by external modulating means which varies the equilibrium position of the slide valve. The slide valve allows the initial alteration of the effective delivery, and hence the effective injection advance, in dependence on the running conditions/load of the engine.

Abstract: A constant-pressure delivery valve for fuel injection pumps for diesel engines includes a conical-surface obturator to which is fixed a body forming an axial chamber containing a calibrated one-way valve with a ball obturator. The ball obturator is located on that side of the chamber facing the conical-surface obturator and controls communication between radial and axial fuel return passages formed beneath the bottom of the chamber.