In a high pressure fuel supply system, a variable speed motor asynchronously actuates a pumping piston with a drive mechanism including a circular cam with cam roller, having an axis that is offset from the axis of the cam drive shaft. A rolling or sliding cam follower is rigidly connected to the piston, and a piston retainer is operatively connected among the piston, the cam follower and the cam roller. As the cam shaft rotates, the cam roller rotates eccentrically relative to the cam shaft while maintaining contact with the cam follower, thereby reciprocating the follower and the piston along the actuation axis, in corresponding charging and pumping strokes of the piston.

A high-pressure fuel pump includes a housing including a chamber, an inlet flow passage to draw fuel into the chamber, and a discharge flow passage to discharge fuel out of the chamber. The high-pressure fuel pump further includes a piston disposed in the housing and configured to compress fuel, a sleeve coupled to the housing and configured to support the piston and form a space for storing fuel, a discharge valve disposed in the discharge flow passage and configured to open when a pressure of fuel stored in the chamber is equal to or greater than a first pressure, and a pressure relief valve disposed in a relief flow passage that communicates with the discharge flow passage and the space. The pressure relief valve is configured to open when a pressure of fuel supplied into the relief flow passage is equal to or greater than a second pressure.

Disclosed herein is a high-pressure fuel pump. The high-pressure fuel pump includes a housing including a chamber provided to compress fuel supplied thereinto, an inlet flow passage that communicates with the chamber to draw fuel into the chamber through the inlet flow passage, and a discharge flow passage that communicates with the chamber to discharge the fuel out of the chamber through the discharge flow passage. The high-pressure fuel pump further includes a piston disposed in the housing and configured to linearly reciprocate to compress the fuel supplied into the chamber; and a discharge valve disposed in the discharge flow passage of the housing and configured to open when a pressure of fuel stored in the chamber is equal to or greater than a first pressure, the discharge valve including an open-and-close member that makes line contact with an inlet of the discharge valve to close the inlet.

A high-pressure fuel pump and a protector are coupled to an outer side of an engine body of an internal combustion engine. A wall plate surrounds the high-pressure fuel pump to protect the high-pressure fuel pump. A cover of the high-pressure fuel pump has a flange. The engine body has a mounting surface. The bottom plate and the flange are fastened to the mounting surface by a bolt with the bottom plate held between the flange and the mounting surface.

A fuel pump includes a fuel pump housing with a pumping chamber; a pumping plunger which reciprocates within a plunger bore; and an inlet valve. The inlet valve includes a valve body having a valve body bore; an inlet passage; and an outlet passage. The inlet valve also includes a check valve which moves between a seated position and an unseated position, wherein the seated position prevents flow through the outlet passage into the valve body bore and the unseated position permits flow through the outlet passage such that the valve body bore is in fluid communication with the pumping chamber. The inlet valve also includes a valve spool which moves between a first position where the valve spool maintains the check valve member in the unseated position and a second position where the check valve member is able to move to the seated position.

A fuel pump includes a cylinder that forms a compression chamber which pressurizes a fuel, a plunger that compresses the fuel in the compression chamber, a cam that pushes the plunger, and a driven gear that engages a driving gear to transmit a rotational driving force. A profile of the cam is configured such that a peak arrival range is half or less of a compression range. Cam speed is obtained by differentiating a lift amount of the plunger by a rotation angle of the cam, the compression range is an angle range during which the plunger is pushed in the direction of compressing the fuel, and the peak arrival range is an angle range from a start of the compression range until a most retarded position of a peak of the cam speed.

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.

A fuel injection pump includes a cylinder formed with a passage of fuel, a plunger, and a swirl flow generating par. The plunger slides along an inner wall of a sliding hole located in the cylinder and reciprocates between an uppermost point and a lowermost point to pressurize the fuel in a pressurizing chamber placed at an end of the sliding hole at a highest point. The plunger is movable downward to cause the pressurizing chamber to inhale the fuel from an intake passage in a fuel suction stroke. The intake passage is communicated to the pressurizing chamber at a lateral side of a plunger axis that is an axis of the plunger in a sliding direction. The swirl flow generating part guides the fuel to form a swirl flow around the plunger axis in the fuel suction stroke.

A pump unit for feeding fuel, preferably diesel fuel, to an internal combustion engine, the pump unit comprising: a head (2) inside which a cylinder (3) is formed along an axis (A) for housing a sliding pumping piston (4); an intake valve (8) positioned inside an intake hole (7) between an intake chamber (9) and a compression chamber (10) upstream and downstream of the intake hole, respectively; a plug (11) sealingly connected to the head (2) so as to close the intake chamber; wherein the sealed connection is formed by means of forced surface-to-surface engagement between a portion of an inner surface of an annular wall of the head and a portion of an outer surface of an annular wall of the plug.

An object of the present invention is to obtain a high pressure fuel supply pump capable of reducing pressure pulsation that occurs in a low pressure pipe, preventing damage to the low pressure pipe, or reducing noise due to vibrations of the low pressure pipe. The present invention provides a high pressure fuel supply pump of a type in which, from a fuel suction port connected to a low pressure pipe provided upstream of a fuel, a low pressure passage, an electromagnetic suction valve driven by an electromagnetic force, a pressurizing chamber in which the volume thereof is increased or reduced by a plunger that is reciprocatingly moved by being guided by a cylinder, and a discharge valve provided at an outlet of the pressurizing chamber are sequentially arranged, a fuel is sucked to the pressurizing chamber through the electromagnetic suction valve, the amount of a part of the fuel, which is sucked to the pressurizing chamber, to be returned to the low pressure passage side is adjusted so that the amount of the fuel to be discharged through the discharge valve is controlled, and the high pressure fuel supply pump includes a backflow suppression mechanism for suppressing backflow of fuel from the fuel from the fuel suction portion to the low pressure pipe side.