The invention relates to a common rail system for an internal combustion engine of a vehicle, comprising a high-pressure pump which delivers highly pressurized fuel to a high-pressure accumulator, from which the fuel is fed to at least one injection valve of the internal combustion engine, a low-pressure pump for conveying fuel from a fuel container via a conveying line to the high-pressure pump, a flow control valve as an electromagnetic switching valve which is arranged in the conveying line for controlling the fuel quantity which is fed by the high-pressure pump to the high-pressure accumulator; it is provided according to the invention that the flow control valve is configured as a ball seat valve with an inlet opening which is connected to the low-pressure pump and an outlet opening which is connected to the high-pressure pump, which ball seat valve is open in the de-energized state.

A high-pressure fuel pump includes a pump housing, a pressurizing member, a suction valve seat, a suction valve body, and a suction valve chamber. The suction valve seat includes a first projected wall section that is projected to an upper side in a vertical direction. The pump housing includes a second projected wall section that is directed to the upper side in the vertical direction. A height of the lowest position in a portion of the second projected wall section that is projected to the upper side in the vertical direction is higher than a height of the lowest position in a portion of the first projected wall section that is projected to the upper side in the vertical direction. A first initial fuel pool is provided on an downstream side of the second projected wall section and on the upstream side of the suction valve seat.

A high-pressure pump includes a pressurizing chamber forming portion, a suction passage forming portion, a seat member, a valve member, a cylindrical member, a needle, a movable core, a biasing member, a fixed core, and a coil including a winding portion. The coil generates an attractive force between the fixed core and the movable core when the winding portion is energized. The coil includes an outer cylindrical surface and multiple inner cylindrical surfaces that have different diameters. The multiple inner cylindrical surfaces are arranged in order of increasing diameter in a direction toward a pressurizing chamber. The movable core has an end surface that faces the fixed core, and the end surface of the movable core is located between a center, in an axial direction, of a smallest diameter one of the plurality of inner cylindrical surfaces and a center, in an axial direction, of the outer cylindrical surface.

A metering valve supplies fuel to and block fuel from a pressurizing chamber by moving a valve body by switching between energization and de-energization of an electromagnetic unit. An energization control unit performs a valve closing control and a valve opening control to reduce operating sound in one opening and closing period in which the valve body opens and closes. A time control unit controls, on determination that the energizing period of the electromagnetic unit exceeds the upper limit value, a moving speed of the valve body when the valve body moves to a valve closing side, such that the energization period of the electromagnetic unit in the one opening and closing period does not exceed the upper limit value, thereby to cause the energization control unit to perform both the valve closing control and the valve opening control in the one opening and closing period.

To suppress the possibility that a body-side holding member comes into contact with a joint portion 92 of a damper mechanism 9. damper cover that is arranged on an upstream side of a pressurizing chamber and is attached to a body to form a damper chamber, a damper mechanism that is arranged in the damper chamber, and a body-side holding member that holds the damper mechanism from the body side are provided. The body-side holding member includes a bottom surface in contact with the body and a flexible portion formed along an urging direction by being urged downward from the damper cover toward the body.

To suppress the possibility that a body-side holding member comes into contact with a joint portion 92 of a damper mechanism 9. damper cover that is arranged on an upstream side of a pressurizing chamber and is attached to a body to form a damper chamber, a damper mechanism that is arranged in the damper chamber, and a body-side holding member that holds the damper mechanism from the body side are provided. The body-side holding member includes a bottom surface in contact with the body and a flexible portion formed along an urging direction by being urged downward from the damper cover toward the body.

An outlet and pressure relief valve assembly for a fuel pump includes a housing which extends along an axis from an inner end to an outer end. The housing has a bore which extends thereinto along the axis from the inner end. A valve seat is located within the bore and has an end wall which is transverse to the axis and also has a sidewall which is annular in shape and extends away from the end wall. An outlet flow passage extends through the end wall such that the outlet flow passage is centered about the axis. A pressure relief flow passage extends through the end wall such that the pressure relief flow passage is laterally spaced from the outlet flow passage. An outlet valve member is located within the valve seat sidewall and a pressure relief valve member is located between the valve seat and the inner end.

Various embodiments include methods for operating a high-pressure pump comprising: driving a piston arranged in a compression chamber with a motor shaft; during movement of the piston toward the top dead center, closing the inlet valve so the fluid is then delivered by the piston through an outlet valve; applying a coil current to an electromagnet used to close the inlet valve during and/or after overshooting the top dead center; detecting a start time at which the coil current, on account of starting of an opening movement of the inlet valve, fulfills a predetermined change criterion; labelling a dead center rotation position of the motor shaft at which the piston is at the top dead center based at least in part on the ascertained start time; and adjusting operation of the pump based on the identified dead center rotation position.

An example valve includes a piston configured to block fluid flow from a first port of the valve to a second port of the valve when the valve is in a closed position; a relief mode spring applying a first biasing force on the piston in a distal direction; a reverse flow spring applying a second biasing force on the piston in a proximal direction, wherein the reverse flow spring is weaker than the relief mode spring; and a pressure setting spring applying a third biasing force on a check element in the distal direction, causing the check element to be seated when the valve is in the closed position.

Various methods and systems are provided for health assessments of a fuel system. In one example, a fuel system includes a high-pressure fuel pump operable to increase fuel pressure from a first pressure to a second pressure, a common fuel rail fluidly coupling the high-pressure fuel pump to a plurality of fuel injectors each of which is operable to inject fuel to individual cylinders of an engine, a pressure sensor operable to detect a pressure of fuel at the common fuel rail, and a controller operable to diagnose a condition of the high-pressure fuel pump based on output from the pressure sensor.