Abstract: A pumping unit has a fuel storage tank (2), a piston pump (6) for feeding the fuel to an internal combustion engine (3); a gear pump (7) for feeding the fuel from the storage tank (2) to the piston pump (6), and a hydraulic circuit (46) which connects together the storage tank (2) and the internal combustion engine (3), extends through a pump body (8) of the piston pump (6) so as to lubricate an actuating shaft (36) of the piston pump (6) and has a collection branch (55) for collecting the fuel leaks resulting from the lubrication of said actuating shaft (36); the collection branch (55) being connected to an intake (37a) of the gear pump (7) so as to lubricate an actuating shaft (42) of the gear pump (7) with the fuel from said collection branch (55).

Abstract: A pumping unit has a fuel storage tank (2), a piston pump (6) for feeding the fuel to an internal combustion engine (3); a gear pump (7) for feeding the fuel from the storage tank (2) to the piston pump (6), and a hydraulic circuit (46) which connects together the storage tank (2) and the internal combustion engine (3), extends through a pump body (8) of the piston pump (6) so as to lubricate an actuating shaft (36) of the piston pump (6) and has a collection branch (55) for collecting the fuel leaks resulting from the lubrication of said actuating shaft (36); the collection branch (55) being connected to an intake (37a) of the gear pump (7) so as to lubricate an actuating shaft (42) of the gear pump (7) with the fuel from said collection branch (55).

Abstract: A high-pressure pump for feeding fuel to an internal combustion engine has a pump housing; a fuel delivery duct; and a check valve, which is arranged along the delivery duct, and comprises a fuel chamber; a valve member mobile within the fuel chamber; and a biasing and guiding assembly, which has a fastening member suitable for being fastened to the pump housing and sealing the fuel chamber in a fluid-tight manner; a helical spring suitable for biasing the valve member; and a bushing arranged about the helical spring in order to prevent bending of the helical spring.

Abstract: A high-pressure pump for feeding fuel to an internal combustion engine has a pump housing; a fuel delivery duct; and a check valve, which is arranged along the delivery duct, and comprises a fuel chamber; a valve member mobile within the fuel chamber; and a biasing and guiding assembly, which has a fastening member suitable for being fastened to the pump housing and sealing the fuel chamber in a fluid-tight manner; a helical spring suitable for biasing the valve member; and a bushing arranged about the helical spring in order to prevent bending of the helical spring.

Abstract: An intake valve for a high pressure pump for internal combustion engine fuel having a valve body having a seat with which cooperates a shutter kept closed by a first spring of substantially constant pressure and by a second spring varying in pressure during at least part of the stroke of the piston. The springs are helical compression types and their pressures are summed on the shutter, which has a plate and a stem. The first spring is located between the valve body and a flange integral with a sleeve fitted to the stem in an adjustable position. The second spring is located between the plate and the piston.

Abstract: The valve (9) has a valve body (36) having a seat (42) with which cooperates a shutter (43) kept closed by a first spring (48) of substantially constant pressure, and by a second spring (49) varyuing in pressure during at least part of the stroke of the piston (7). The springs (48, 49) are helical compression types, and their pressures are summed on the shutter (43), which has a plate (44) and a stem (46). The first spring (48) is located between the valve body (36) and a flange (52) integral with a sleeve (53) which is fitted to the stem (46) in an adjustable position; and the second spring (49) is located between the plate (44) and the piston (7).