An outlet valve includes an outlet valve housing with an outlet valve bore including an outlet valve seating surface. The outlet valve also includes an outlet valve member which moves within the outlet valve bore second portion between a closed position and an open position. A surface of the outlet valve bore guides the outlet valve member during movement between the closed position and the open position. The surface of the outlet valve bore and the outlet valve seating surface are provided on a continuous piece of material of the outlet valve housing. An outlet valve spring biases the outlet valve member toward the closed position and a retainer is fixed to the outlet valve housing which grounds the outlet valve spring to the outlet valve housing.

A high pressure fuel pump includes a pressurizing assembly where a plunger arranged in a bore translates along a main axis. The pump also includes a fuel transfer assembly having an inlet valve assembly and an outlet valve assembly. The pressurizing assembly has a pressurizing body provided with the bore and the fuel transfer assembly has a fuel transfer body within which are arranged the inlet and the outlet valve assemblies. The pressurizing body and the fuel transfer body are distinct parts fixed to each other along a sealing area.

There is provided a discharge valve mechanism provided at an outlet of a pressurizing chamber of a high-pressure fuel supply pump that aims to reduce a backflow amount of fuel from a discharge valve and to prevent cavitation erosion. There are provided a discharge valve disposed on a discharge side of a pressurizing chamber, a discharge valve seat that closes a discharge side flow passage of the pressurizing chamber by seating the discharge valve, and a discharge valve spring that presses the discharge valve toward the discharge valve seat. It is configured such that, in a case where a minimum seat diameter of a seat portion in which the discharge valve is seated on the discharge valve seat is set to D and a spring force of the discharge valve spring at a time of setting is set to F, a coefficient K obtained by dividing the spring force F by the minimum seat diameter D is set to be 0.2 or more.

A fuel pump includes a fuel pump housing made of stainless steel and having a pumping chamber therewithin, a plunger bore extending thereinto, an inlet passage extending thereinto, and an outlet passage extending thereinto. A pumping plunger reciprocates within the plunger bore such that an intake stroke of the pumping plunger increases volume of the pumping chamber and a compression stroke of the pumping plunger decreases volume of the pumping chamber. An outlet valve controls fuel flow from the pumping chamber out of the fuel pump housing. The outlet valve includes an outlet valve seating surface formed by the fuel pump housing within the outlet passage such that a nitrided layer extends from the outlet valve seating surface into the fuel pump housing. The outlet valve also includes an outlet valve member within the outlet passage which is moveable between a seated position and an unseated position.

A fuel supply pump includes a pressurizing chamber, a high-pressure path, and a valve unit. The valve unit includes an outlet valve which is configured to open to allow fuel in the pressurizing chamber to flow to the high-pressure path when fuel pressure in the pressurizing chamber becomes higher than a first predetermined pressure. The valve unit also includes a pressure relief valve which is configured to open to allow fuel in the high-pressure path to return to the pressurizing chamber when fuel pressure in the high-pressure path becomes higher than a second predetermined pressure. The valve unit also includes a valve seat member in which a relief path and a plurality of outlet paths are formed, wherein a first end of the relief path opens on a relief valve seat for the pressure relief valve, and respective first ends of the plurality of outlet paths open on an outlet valve seat for the outlet valve.

The disclosure relates to a fuel injection system having a valve arrangement for connecting a pressure chamber of a high-pressure fuel pump to a high-pressure accumulator. The valve arrangement has an outlet valve and a pressure-limiting valve. An outlet valve seat and a pressure-limiting valve seat are formed on a common valve seat element which is formed in one piece, and are arranged eccentrically with respect to one another.

A direct-injection, supercharged internal combustion engine having at least one cylinder, in which each cylinder is equipped with a direct injection apparatus, a fuel supply system comprising a high-pressure side and a low-pressure side, and a high-pressure piston pump comprising a piston displaceable in translational fashion between a bottom dead center and a top dead center of a pressure chamber of variable volume. The displaceable piston jointly delimits the pressure chamber with variable volume in such a way that a displacement of the piston causes a change in the volume of the pressure chamber via actuation of least one movable actuation element.

To provide a high-pressure fuel supply pump having a relief valve mechanism capable of suppressing deterioration of the seat property due to the influence of deformation caused by press-fitting while press-fitting and fixing a relief seat. To achieve this, a relief seat 201 of a relief valve mechanism 200 has, on its inner peripheral side, a seat portion 201a on which a valve 202 is seated, a small-diameter channel portion 201b formed with a smaller diameter than the valve 202 on an upstream side of the seat portion 201a, and a large-diameter channel portion 201c formed with a larger diameter than the small-diameter channel portion 201b on an upstream side of the small-diameter channel portion 201b, and, on its outer peripheral side, a fine gap portion 201d formed between the relief seat 201 and a member arranged on an outer peripheral side of the relief seat 201 at a position overlapping the small-diameter channel portion 201b in a flow direction of the fuel, and a press-fit portion 205a coming into contact with the member when the relief seat 201 is press-fitted into the member at a position overlapping the large-diameter channel portion 201c in the flow direction of the fuel.

A fuel injection pump includes a cam rotating with a camshaft, a tappet reciprocating in response to rotation of the cam, a cylinder, a plunger, and a thrust washer. The thrust washer is located between the cam and a casing housing the camshaft at both ends of the cam in an axial direction of the cam. The tappet includes a tappet body, a roller, a supporting member, and a contact surface formed at an outer peripheral part of the tappet. The thrust washer includes a rotation restricting part that protrudes toward the tappet over a maximum lift position. The rotation restricting part restricts rotation of the tappet relative to a center axis of the tappet body by being contact with the contact surface.

A combination outlet valve and pressure relief valve includes an outer housing having a passage. An inner housing is located within the passage and includes a first bore extending thereinto from one end and a second bore extending thereinto from the other end such that the first bore and the second bore terminate at an inner housing wall. An outlet valve assembly is located within the first bore and includes an outlet valve member, an outlet valve seat, and an outlet valve spring grounded to the inner housing wall and biasing the outlet valve member toward the outlet valve seat. A pressure relief valve assembly is located within the second bore and includes a pressure relief valve member, a pressure relief valve seat, and a pressure relief valve spring grounded to the inner housing wall and biasing the pressure relief valve member toward the pressure relief valve seat.