A pump body of a high-pressure pump includes a pressure chamber formed in a deep portion of a cylinder. A plunger reciprocates within the cylinder to vary a volume of the pressure chamber. A discharge path and a supply path are formed in the pump body and extend in a radial direction of the cylinder from the pressure chamber. A pin provided at an end of the plunger in the pressure chamber protrudes in one radial direction of the plunger to the outside of an inner circumference of the cylinder. In this case, the pin is engaged with a step portion between the cylinder and the pressure chamber in a state before attachment of the high-pressure pump to an internal combustion engine. Accordingly, separation of the plunger from the cylinder is avoidable.

A pump body of a high-pressure pump includes a pressure chamber formed in a deep portion of a cylinder. A plunger reciprocates within the cylinder to vary a volume of the pressure chamber. A discharge path and a supply path are formed in the pump body and extend in a radial direction of the cylinder from the pressure chamber. A pin provided at an end of the plunger in the pressure chamber protrudes in one radial direction of the plunger to the outside of an inner circumference of the cylinder. In this case, the pin is engaged with a step portion between the cylinder and the pressure chamber in a state before attachment of the high-pressure pump to an internal combustion engine. Accordingly, separation of the plunger from the cylinder is avoidable.

A pump body of a high-pressure pump includes a pressure chamber formed in a deep portion of a cylinder. The pump body closes the pressure chamber on a side opposite to a plunger. The plunger reciprocates within the cylinder to vary a volume of the pressure chamber. The large-diameter portion provided at an end of the plunger on a side protruding to the pressure chamber has an outside diameter larger than an inside diameter of the cylinder and smaller than an inside diameter of the pressure chamber. In this case, the large-diameter portion is engaged with a step portion between the cylinder and the pressure chamber in a state before attachment of the high-pressure pump to an internal combustion engine. Accordingly, separation of the plunger from the cylinder is avoidable.

A plunger of a high-pressure pump is provided reciprocatably on an inner side of a cylinder. A holder disposed on an opposite side of the cylinder from a pressurizing chamber includes a large tubular portion that provides a predetermined space between the large tubular portion and an outer wall of the plunger, and a small tubular portion that is disposed on an opposite side of the large tubular portion from the cylinder. A pin inserted into a hole of the plunger at a position corresponding to the large tubular portion protrudes radially outward from the outer wall of the plunger and is accommodated in a space on an inner side of the large tubular portion.

A plunger of a high-pressure pump is provided reciprocatably on an inner side of a cylinder. A holder disposed on an opposite side of the cylinder from a pressurizing chamber includes a large tubular portion that provides a predetermined space between the large tubular portion and an outer wall of the plunger, and a small tubular portion that is disposed on an opposite side of the large tubular portion from the cylinder. A pin inserted into a hole of the plunger at a position corresponding to the large tubular portion protrudes radially outward from the outer wall of the plunger and is accommodated in a space on an inner side of the large tubular portion.

A high-pressure fuel pump includes a pump housing, a pump piston accommodated in a receiving opening of the pump housing, a high-pressure seal which surrounds the pump piston in a sealing manner and which seals off a high-pressure region from a low-pressure region, and a guide device which comprises at least two guide portions that are axially spaced apart from one another and guide the pump piston with a sliding fit. The at least two guide portions are arranged in the receiving opening of the pump housing. A first guide portion is arranged, as seen in an axial direction, on a side of the high-pressure seal facing toward the delivery space. And a second guide portion is arranged, as seen in the axial direction, on a side of the high-pressure seal facing away from the delivery space.

A high-pressure fuel pump includes a pump housing, a pump piston accommodated in a receiving opening of the pump housing, a high-pressure seal which surrounds the pump piston in a sealing manner and which seals off a high-pressure region from a low-pressure region, and a guide device which comprises at least two guide portions that are axially spaced apart from one another and guide the pump piston with a sliding fit. The at least two guide portions are arranged in the receiving opening of the pump housing. A first guide portion is arranged, as seen in an axial direction, on a side of the high-pressure seal facing toward the delivery space. And a second guide portion is arranged, as seen in the axial direction, on a side of the high-pressure seal facing away from the delivery space.

A fuel pump module for a vehicle, which is formed in a low-floor type fuel pump module capable of being easily installed in a fuel tank with a reduced vertical height. The fuel pump module includes a head plate to be mounted in an opening of a fuel tank, a reservoir cup to which the head plate is pivotably coupled through a pair of connecting bars and which is to be installed in the fuel tank in a state of being coupled to the head plate, a fuel pump disposed in the reservoir cup in a state of being laid and to deliver fuel in the reservoir cup to an outside of the fuel tank, and a jet pump installed in the reservoir cup and to suction fuel outside the reservoir cup and discharge the fuel into the reservoir cup.

A fuel pump module for a vehicle, which is formed in a low-floor type fuel pump module capable of being easily installed in a fuel tank with a reduced vertical height. The fuel pump module includes a head plate to be mounted in an opening of a fuel tank, a reservoir cup to which the head plate is pivotably coupled through a pair of connecting bars and which is to be installed in the fuel tank in a state of being coupled to the head plate, a fuel pump disposed in the reservoir cup in a state of being laid and to deliver fuel in the reservoir cup to an outside of the fuel tank, and a jet pump installed in the reservoir cup and to suction fuel outside the reservoir cup and discharge the fuel into the reservoir cup.

A high-pressure fuel pump includes a pump housing, a receiving space in the pump housing, a pressure pulsation damper in the form of a diaphragm cell having two diaphragms, which pressure pulsation damper is arranged in the receiving space, and a holding device for holding the diaphragm cell in the receiving space. The holding device includes a connection portion, which is connected to the pump housing rigidly both in an axial direction and in a radial direction. The connection portion is fastened to the pump housing, both in the axial direction and in the radial direction, to an inner lateral surface of the pump housing that delimits the receiving space.