A valve member includes a specific range in which an overlap area that is an area in which a hole opening and a slide outer wall are overlapped with each other becomes gradually smaller and a minimum passage area that is a passage area between an intermediate chamber and a first hole being minimum becomes gradually larger as the valve member is moved in a direction away from a valve seat portion in a movable range in the axial direction.

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.

A high-pressure fuel pump includes a housing including a chamber, an inlet flow passage to draw fuel into the chamber, and a discharge flow passage to discharge fuel out of the chamber. The high-pressure fuel pump further includes a piston disposed in the housing and configured to compress fuel, a sleeve coupled to the housing and configured to support the piston and form a space for storing fuel, a discharge valve disposed in the discharge flow passage and configured to open when a pressure of fuel stored in the chamber is equal to or greater than a first pressure, and a pressure relief valve disposed in a relief flow passage that communicates with the discharge flow passage and the space. The pressure relief valve is configured to open when a pressure of fuel supplied into the relief flow passage is equal to or greater than a second pressure.

A relief valve, capable of reducing pressure of fuel in a discharge passage and including a valve housing having a communication hole and a valve member provided in a reciprocating manner against the valve housing, where the valve member regulates a flow of the fuel between a discharge passage and a fuel chamber when the valve member is brought into contact with an inner wall formed around the communication hole. T the valve member also allows the flow of the fuel between the discharge passage and the fuel chamber when the valve member is separated from the inner wall. The relief valve further including a spring that biases the valve member such that the valve member and the inner wall are in contact with each other an adjusting pipe and a stopper.

A fuel pump includes a fuel pump housing with a pumping chamber and an outlet valve bore extending along an outlet valve bore axis; a pumping plunger which reciprocates within a plunger bore along a plunger bore axis which is traverse to the outlet valve bore axis; and an outlet valve assembly. The outlet valve assembly includes an outlet valve seat with an outlet flow passage, wherein a first portion of the outlet valve seat is aligned with the pumping plunger in a direction parallel to the plunger bore axis and wherein a second portion of the outlet valve seat is not aligned with the pumping plunger in a direction parallel to the plunger bore axis and an outlet valve member which is moveable between an unseated position which provides fluid communication through the outlet flow passage and a seated position which prevents fluid communication through the outlet flow passage.

The invention relates to a high-pressure fuel pump (10) having a housing (12) in which a pressure-limiting valve (38) is arranged in a bore (36), wherein the bore (36) leads into an inflow volume (30) of a low-pressure inflow (22).

A metering valve is installed in a feed passage that supplies low pressure fuel, which is fed from a feed pump, to a pressurizing chamber. The metering valve adjusts a discharge amount of the low pressure fuel discharged from the pressurizing chamber. A first pressure regulating valve is opened in a case where a pressure of the low pressure fuel becomes equal to or larger than a first preset pressure. A second pressure regulating valve is opened in a case where the pressure of the low pressure fuel becomes equal to or larger than a second preset pressure. The first pressure regulating valve and the second pressure regulating valve are configured such that a degree of responsiveness of valve opening and closing of the second pressure regulating valve is higher than a degree of responsiveness of valve opening and closing of the first pressure regulating valve.

A system for protecting a high-pressure accumulator fuel injection system of an internal combustion engine against excessively high fuel pressures occurring in a high-pressure accumulator of the fuel injection system caused by a malfunction in the fuel injection, wherein the system comprises a member measuring the fuel pressure inside the high-pressure accumulator and sending information about this pressure to a control unit. An electrically controllable inlet valve to a pumping element of a high-pressure pump is included in the system and controlled by the control unit to be transferred to a continuously open or closed state, if the pressure measured exceeds a predetermined pressure level for stopping the feeding of fuel by the pumping element to the high-pressure accumulator.

Disclosed herein is a high-pressure fuel pump. The high-pressure fuel pump includes a housing including a chamber provided to compress fuel supplied thereinto, an inlet flow passage that communicates with the chamber to draw fuel into the chamber through the inlet flow passage, and a discharge flow passage that communicates with the chamber to discharge the fuel out of the chamber through the discharge flow passage. The high-pressure fuel pump further includes a piston disposed in the housing and configured to linearly reciprocate to compress the fuel supplied into the chamber; and a discharge valve disposed in the discharge flow passage of the housing and configured to open when a pressure of fuel stored in the chamber is equal to or greater than a first pressure, the discharge valve including an open-and-close member that makes line contact with an inlet of the discharge valve to close the inlet.

A fuel pressure regulator includes a fuel inlet; a fuel outlet; a seating surface; and a valve member assembly. The valve member assembly includes a poppet and also includes a sealing member which is made of an elastomer material and which is annular in shape and including a sealing member surface. The sealing member is supported by the poppet. The valve member assembly is moveable between 1) a closed position in which the sealing member surface engages the seating surface, thereby preventing fuel flow from the fuel inlet to the fuel outlet and 2) an open position in which the sealing member surface is spaced apart from the seating surface, thereby allowing fuel flow from the fuel inlet to the fuel outlet.