Metering valve for a pump unit for feeding fuel to internal combustion engine and pump unit comprising such a valve

A plug (33) for a metering valve (7) of a pump unit (1) for feeding fuel from a tank (2) to an internal combustion engine (3);

• wherein the metering valve (7) comprises:
• a sleeve (27) having an axis (A) and provided with a first open end for receiving a thruster (21), a second opposite end provided with an opening (35) for axially discharging the fuel and at least one side opening (28) for feeding fuel;
• and
• a plug-shaped piston (30) slidably housed along the axis (A) inside the sleeve (27), the piston (30) having a closed end (31) with an outer surface in contact with the thruster (21), an open opposite end and at least one side opening (34);
• wherein the plug (33) is shaped so as to be stably housed inside the discharge opening (35) of the sleeve and provided with an axial opening (38);
• and
• wherein the plug (33) is shaped so that, when the plug is housed inside the axial discharge opening (35), at least one lateral flow channel (39) for discharging fuel is present
• wherein the piston (30) has at least one side opening (34) cooperating with the side opening (28) of the sleeve (27) so that, selectively, fuel passes through the side opening (28) of the sleeve (27) and the side opening (34) of the piston (30) and is discharged via the open end of the piston (30), and
• wherein the plug (33) is provided with an axial through-hole (38) centered on the axis (A).

A method for increasing the flowrate of a metering valve (7) of a pump unit (1) for feeding fuel from a tank (2) to an internal combustion engine (3) without modifying the dimensions and the possibility of standardization of the components, the method comprising the steps of:

• a) providing a valve (7) comprising a sleeve (27) having an axis (A) and provided with a first open end for receiving a thruster (21), a second opposite end provided with an opening (35) for axially discharging the fuel and at least one side opening (28) for feeding fuel;
• a plug-shaped piston (30) slidably housed along the axis (A) inside the sleeve (27), the piston (30) having a closed end (31) with an outer surface in contact with the thruster (21), an open opposite end and at least one side opening (34);
• a plug (33) housed inside the discharge opening (35) of the sleeve and provided with an axial opening (38);
• a spring (32) arranged between the plug (33) and the inner surface of the closed end (31) of the sleeve;
• the piston (30) having at least one side opening (34) cooperating with the side opening (28) of the sleeve (27) so that, selectively, fuel passes through the side opening (28) of the sleeve (27) and the side opening (34) of the piston (30) and is discharged via the open end of the piston (30);
• and wherein the plug (33) is provided with an axial through-hole (38) centered on the axis (A);
• and
• b) providing the plug (33) with a shape so that, when the plug is housed inside the axial discharge opening (35), at least one lateral flow channel (39) for discharging the fuel is present.