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 includes a pump housing with a pumping chamber an inlet valve bore. An inlet valve selectively provides and prevents fluid communication between an inlet of the fuel pump and the pumping chamber. The inlet valve includes an inner housing received within the inlet valve bore such that an outer periphery of the inner housing is sealed to an inner periphery of the inlet valve bore. An outer housing circumferentially surrounds the inner housing. An annular chamber is defined radially between the inner housing and the outer housing and axially between the outer housing and the pump housing. A sealing ring is located within the annular chamber such that the sealing ring is compressed axially against the pump housing and the outer housing.

A fuel pump includes a pump housing with a pumping chamber an inlet valve bore. An inlet valve selectively provides and prevents fluid communication between an inlet of the fuel pump and the pumping chamber. The inlet valve includes an inner housing received within the inlet valve bore such that an outer periphery of the inner housing is sealed to an inner periphery of the inlet valve bore. An outer housing circumferentially surrounds the inner housing. An annular chamber is defined radially between the inner housing and the outer housing and axially between the outer housing and the pump housing. A sealing ring is located within the annular chamber such that the sealing ring is compressed axially against the pump housing and the outer housing.

A fuel pump for a direct injection system and having: a main body; a pumping chamber; a piston, which is mounted in a sliding manner on the inside of the pumping chamber; an intake duct, which ends in the pumping chamber; an intake valve, which is arranged along the intake duct; and a flow rate adjustment device provided with a control rod which is coupled to the intake valve and with an electromagnetic actuator which is configured to axially move the control rod. The flow rate adjustment device has a containing element, which houses the electromagnetic actuator, has an open end facing the intake valve, and ends with a “U”-shaped rim which has an outer ring which is arranged around the containing element at a given distance from a cylindrical wall of the containing element. An annular weld (22) is obtained between the main body and the outer ring of the “U”-shaped rim.

An actuator includes a housing, a first chamber inside the housing, a cylinder within the housing, and a second chamber within the housing. The cylinder fluidically isolates the first chamber from the second chamber. The actuator also includes a rod connected to the cylinder and extending through the second chamber and the housing. A shell is spaced apart from the housing and defines a fluid gap between the shell and the housing. The shell includes a shell inlet fluidically connected to the fluid gap and a shell outlet fluidically connected to the fluid gap.

A pump unit for supplying fuel, preferably diesel oil, to an internal combustion engine has at least two cylinders (10), which are formed in at least one head (9), are slidingly engaged by respective pistons (13), and communicate hydraulically with respective fuel inlets (11) in the cylinders (10) via respective interposed intake valves (15) provided with respective valve bodies (16) incorporated in the head (9); the inlets (11) of all the cylinders (10) being closed by a single cover (33) fixed to the head (9).

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.

A high pressure pump for complex injection engines is provided. A body of the high pressure pump includes a first flow path that transports the low pressure fuel flowing in through the low pressure fuel inlet and a low pressure fuel storage chamber that is disposed in a lower portion of the body to store the low pressure fuel transported from the first flow path. A second flow path transports the low pressure fuel stored in the low pressure fuel storage chamber and a flow control valve is disposed over the low pressure fuel storage chamber to discharge the low pressure fuel, transported through the second flow path, to the pressure unit or the damper disposed in an upper portion of the body based on an opening or closing operation. A low pressure fuel outlet discharges the low pressure fuel, transported through the damper, to a low pressure fuel rail.

A fuel supply device includes an injector, a fuel pressurization device and an ECU. The fuel pressurization device includes an electromagnetic valve. The fuel pressurization device is configured to pressurize a fuel in accordance with opening/closing of the electromagnetic valve and discharge the fuel toward the injector. The ECU is configured: to control the opening/closing of the electromagnetic valve to adjust the fuel amount discharged toward the injector; to execute an operation sound suppression control during a low-load operation of an engine by reducing an opening/closing frequency of the electromagnetic valve and increasing the fuel amount discharged for each opening/closing of the electromagnetic valve; not to execute the operation sound suppression control when a partial lift injection is in progress; and to execute the operation sound suppression control when the partial lift injection is not in progress.

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.