An outlet valve includes an outlet valve housing with an outlet valve bore including an outlet valve seating surface. The outlet valve also includes an outlet valve member which moves within the outlet valve bore second portion between a closed position and an open position. A surface of the outlet valve bore guides the outlet valve member during movement between the closed position and the open position. The surface of the outlet valve bore and the outlet valve seating surface are provided on a continuous piece of material of the outlet valve housing. An outlet valve spring biases the outlet valve member toward the closed position and a retainer is fixed to the outlet valve housing which grounds the outlet valve spring to the outlet valve housing.

There is provided a discharge valve mechanism provided at an outlet of a pressurizing chamber of a high-pressure fuel supply pump that aims to reduce a backflow amount of fuel from a discharge valve and to prevent cavitation erosion. There are provided a discharge valve disposed on a discharge side of a pressurizing chamber, a discharge valve seat that closes a discharge side flow passage of the pressurizing chamber by seating the discharge valve, and a discharge valve spring that presses the discharge valve toward the discharge valve seat. It is configured such that, in a case where a minimum seat diameter of a seat portion in which the discharge valve is seated on the discharge valve seat is set to D and a spring force of the discharge valve spring at a time of setting is set to F, a coefficient K obtained by dividing the spring force F by the minimum seat diameter D is set to be 0.2 or more.

Disclosed is a method and a device for predicting the failure time of the pressure limiting valve of a high-pressure fuel pump of a motor vehicle. The method includes measuring a characteristic parameter of the pressure limiting valve each time the motor vehicle has been switched off, determining and storing a variable determined by using the measured characteristic parameter, determining the time profile of the variable determined from the characteristic parameter, predicting the future profile of the variable determined from the characteristic parameter, and comparing the predicted future profile of the variable determined from the characteristic parameter with a predetermined wear limiting value. The comparison is to predict the time at which the predicted future profile of the variable determined from the characteristic parameter reaches the predetermined wear limiting value.

A fuel supply pump includes a pressurizing chamber, a high-pressure path, and a valve unit. The valve unit includes an outlet valve which is configured to open to allow fuel in the pressurizing chamber to flow to the high-pressure path when fuel pressure in the pressurizing chamber becomes higher than a first predetermined pressure. The valve unit also includes a pressure relief valve which is configured to open to allow fuel in the high-pressure path to return to the pressurizing chamber when fuel pressure in the high-pressure path becomes higher than a second predetermined pressure. The valve unit also includes a valve seat member in which a relief path and a plurality of outlet paths are formed, wherein a first end of the relief path opens on a relief valve seat for the pressure relief valve, and respective first ends of the plurality of outlet paths open on an outlet valve seat for the outlet valve.

Embodiments relate to an operating method for operating a fuel injection system of an internal combustion engine, wherein, upon a detection of a fault in the fuel injection system, and wherein a predefined pressure is overshot in a high-pressure region of the fuel injection system, an overrun mode of the internal combustion engine is deactivated, such that the internal combustion engine is operated exclusively in an injection mode.

The disclosure relates to a fuel injection system having a valve arrangement for connecting a pressure chamber of a high-pressure fuel pump to a high-pressure accumulator. The valve arrangement has an outlet valve and a pressure-limiting valve. An outlet valve seat and a pressure-limiting valve seat are formed on a common valve seat element which is formed in one piece, and are arranged eccentrically with respect to one another.

To provide a high-pressure fuel supply pump having a relief valve mechanism capable of suppressing deterioration of the seat property due to the influence of deformation caused by press-fitting while press-fitting and fixing a relief seat. To achieve this, a relief seat 201 of a relief valve mechanism 200 has, on its inner peripheral side, a seat portion 201a on which a valve 202 is seated, a small-diameter channel portion 201b formed with a smaller diameter than the valve 202 on an upstream side of the seat portion 201a, and a large-diameter channel portion 201c formed with a larger diameter than the small-diameter channel portion 201b on an upstream side of the small-diameter channel portion 201b, and, on its outer peripheral side, a fine gap portion 201d formed between the relief seat 201 and a member arranged on an outer peripheral side of the relief seat 201 at a position overlapping the small-diameter channel portion 201b in a flow direction of the fuel, and a press-fit portion 205a coming into contact with the member when the relief seat 201 is press-fitted into the member at a position overlapping the large-diameter channel portion 201c in the flow direction of the fuel.

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.

An isolation mechanism for isolating a submerged pump in a storage vessel, where the isolation mechanism comprises a primary valve member and a secondary valve member, which are both biased in a fail-closed position. The isolation mechanism allows for redundancy for safety and reliability, and can be operated externally of the storage vessel. Furthermore, the isolation mechanism comprises venting and purging devices for safe operation of removal and installation of the pump in the storage vessel.

A high-pressure pump includes a pressurizing chamber forming portion, a discharge passage forming portion, a discharge seat member, an intermediate member, a relief seat member, a discharge valve, and a relief valve. The intermediate member includes a first passage that passes through the intermediate member between one surface facing a pressurizing chamber and the other surface facing away from the pressurizing chamber. The relief valve seat includes a second passage that passes through the relief seat member between the one surface facing the pressurizing chamber and the other surface facing away from the pressurizing chamber. At least one of the intermediate member and the relief seat member includes an annular recess that fluidly connects the first passage and the second passage. The annular recess is recessed from a surface of the at least one of the intermediate member and the relief seat member facing the other.