A pump for a fuel delivery system comprises a main housing and a plunger housing arranged to couple to the main housing so as to define a compression chamber therebetween. The main housing and the plunger housing comprise respective first and second opposed faces which are arranged to form a seal therebetween. The main housing comprises a projecting portion which projects from the first face of the main housing through an opening in the second face of the plunger housing into a plunger bore.

A guide for a piston of a high-pressure pump includes: an upper body and a lower body, a connection part integrally connecting the upper body and the lower body, and a seal molded by an insert injection between the upper body and the lower body while surrounding the connection part. A gap exists between the upper body and the lower body, and the piston and the seal are in close contact with a piston. Therefore, it is possible to prevent leakage of fuel even while securing motion performance of the piston.

A fuel pump for an internal combustion engine comprising a barrel having a longitudinal axis that spans between a proximal end and a distal end and a central bore therein. A plunger is disposed at least partially in the central bore and is configured to move along the longitudinal axis. An annular seal assembly is arranged around the circumference of the plunger wherein the annular seal assembly includes a seal retainer housing and a first seal and the seal retainer housing also retains the proximal end of the barrel thereon to form a second seal wherein the first and the second seals reduce the fuel to oil transfer rate and the oil to fuel transfer rate. The plunger and barrel are configured to be removed from and re-assembled with the annular seal assembly to enable service of these parts and the fuel pump.

A high pressure pump includes a housing with a chamber formed inside and a flow control valve and a discharge check valve installed in the chamber; a piston installed to operate up and down in an assembly hall formed in the housing to compress fuel in the chamber to a high pressure; a cylinder forming a gap between an inner circumferential surface and the piston and guiding reciprocation of the piston; and a support member seated on a stepped surface of the housing to surround an outside of the cylinder and configured to elastically support the housing and the cylinder, thereby reducing friction while preventing fuel leakage between the piston and the cylinder.

The disclosed inlet check valve is used in a high pressure fuel pump and is comprised of a valve member integrally connected to a valve stem which is coupled to an inlet valve armature. The valve member has a stroke along an axis between an open position and a closed position. An inlet valve solenoid generates a magnetic field in an inlet valve pole to attract the inlet valve armature and move the valve member from the open position to the closed position. In the open position, the valve member contacts an inlet valve stop and a gap greater than the stroke of the valve member is defined along the axis between the inlet valve armature and the inlet valve pole. In the closed position, an inlet valve seat mates with the valve member and an armature gap remains between the inlet valve armature and the inlet valve pole.

In order to provide a piston device that is of simple construction and provides optimised sealing, it is proposed that the piston device should include the following: a housing that includes a piston receptacle; a piston that is arranged to be linearly displaceable in the piston receptacle; a main gasket element that separates a first medium space from a second medium space, and a supplementary gasket element, different from the main gasket element, for sealing in a region between the piston and the piston receptacle.

A high pressure fuel pump includes a pump housing, pressure and damper chambers, a metal diaphragm, a press-fitted portion, and a weld portion. The pressure chamber is provided in the pump housing. The damper chamber is formed by the pump housing and a damper cover. The metal diaphragm damper is arranged in the damper chamber. At the press-fitted portion, an annular surface of the damper cover is press fitted to an annular surface of the pump housing. The weld portion fixes the damper cover to the pump housing at an entire circumference of the press-fitted portion.

Provided is a high-pressure fuel supply pump capable of reducing a manufacturing cost of a part for holding a metal damper. The high-pressure fuel supply pump includes a pump body 1 having a pressurizing chamber 11 therein, a damper cover 14 forming a damper chamber 10 together with the pump body 1 on the upstream side of the pressurizing chamber 11, a metal damper 9 that is disposed in the damper cover 10 and formed by laminating two metal diaphragms, and a first holding member 9a that is disposed in the damper chamber 10 and presses and holds the metal damper 9 from one side. The first holding member 9a includes a first regulation portion that regulates the radial movement of the metal damper 9, and a second regulation portion that regulates the radial movement of the first holding member 9a in the damper chamber 10. At a position of the second regulation portion, a flow path is formed which allows the fuel in the damper chamber 10 to circulate to both surfaces of the metal damper 9.

A guide for a piston of a high-pressure pump includes: an upper body and a lower body, a connection part integrally connecting the upper body and the lower body, and a seal molded by an insert injection between the upper body and the lower body while surrounding the connection part. A gap exists between the upper body and the lower body, and the piston and the seal are in close contact with a piston. Therefore, it is possible to prevent leakage of fuel even while securing motion performance of the piston.

A piston pump as a high-pressure fuel pump of a common rail system includes: a pump cylinder; a pump piston moveably mounted in a recess of the pump cylinder, the pump piston being moveable up and down in the recess; and a leakage groove arranged in the pump cylinder in a region of the recess, the leakage groove being coupled with a leakage line configured to discharge a fuel leakage. Between the pump cylinder and the pump piston a different size pairing clearance is formed in first and second portions of the pump cylinder.