A roller for a mechanical fuel pump assembly includes an elongate body extending from a first axial end to a second axial end of the elongate body over an overall length of the elongate body. The elongate body defines an effective length that is less than the overall length. The elongate body defines a uniform circular cross section over a second length of the elongate body. The second length is 75 to 90 percent of the effective length and the second length extends between a first plane and a second plane. A first area of reduced cross section extends axially outward from the first plane to a third plane located axially inward of the first axial end; and a second area of reduced cross section extends axially outward from the second plane to a fourth plane located axially inward of the second axial end.

A roller for a mechanical fuel pump assembly includes an elongate body extending from a first axial end to a second axial end of the elongate body over an overall length of the elongate body. The elongate body defines an effective length that is less than the overall length. The elongate body defines a uniform circular cross section over a second length of the elongate body. The second length is 75 to 90 percent of the effective length and the second length extends between a first plane and a second plane. A first area of reduced cross section extends axially outward from the first plane to a third plane located axially inward of the first axial end; and a second area of reduced cross section extends axially outward from the second plane to a fourth plane located axially inward of the second axial end.

Methods and systems are provided for operating a fuel system comprising two lift pumps. In one example, a method may comprise adjusting operation of a first lift pump to achieve a desired fuel rail pressure. The method may comprise powering on a second lift pump to achieve the desired fuel rail pressure when operating only the first lift pump is not sufficient to achieve the desired fuel rail pressure.

Methods and systems are provided for operating a fuel system comprising two lift pumps. In one example, a method may comprise adjusting operation of a first lift pump to achieve a desired fuel rail pressure. The method may comprise powering on a second lift pump to achieve the desired fuel rail pressure when operating only the first lift pump is not sufficient to achieve the desired fuel rail pressure.

A fluid filtering device may have a body that include a fluid collection portion, a filtering chamber, and a passthrough bore. The fluid collection portion may be configured to collect fluid supplied to the fluid filtering device. The filtering chamber may be in fluid communication with the fluid collection portion. The filtering chamber may have an entrance portion, an exit portion, and a fluid filter. The filtering chamber may be configured to filter the fluid supplied to the fluid filtering device. The passthrough bore may be in fluid communication with the filtering chamber and may be separate from the fluid collection portion such that fluid flowing from the fluid collection portion flows into the filtering chamber, and the fluid flowing from the filtering chamber flows into the passthrough bore.

A damper for a high-pressure pump includes a housing and a cover that can be coupled to the housing to form a damping space. The cover has an elevation including a plurality of concave regions and a plurality of convex regions, wherein the concave and convex regions are arranged about a central region of the elevation. Each of the concave regions is arranged between two of the convex regions in order to scatter sound.

A damper for a high-pressure pump includes a housing and a cover that can be coupled to the housing to form a damping space. The cover has an elevation including a plurality of concave regions and a plurality of convex regions, wherein the concave and convex regions are arranged about a central region of the elevation. Each of the concave regions is arranged between two of the convex regions in order to scatter sound.

A diaphragm includes a flange and a protrusion provided to protrude to one side of the flange, wherein the protrusion has at least two annular curved portions provided annularly on a ceiling portion having a flat surface-like shape and an outer side in a radial direction of the ceiling portion, in a state where pressure on an outer wall side of the protrusion and pressure on an inner wall side of the protrusion are the same, the at least two annular curved portions are each formed to be curved in a cross-section of the diaphragm obtained by cutting the diaphragm by a virtual plane including a center line of the diaphragm, the centers of curvature of the curved portions being arranged at different positions on a side opposite to a protruding direction of the protrusion, and the diaphragm is formed of a sheet metal.

A high pressure pump includes a housing with a chamber formed inside and a flow control valve and a discharge check valve installed in the chamber; a piston installed to operate up and down in an assembly hall formed in the housing to compress fuel in the chamber to a high pressure; a cylinder forming a gap between an inner circumferential surface and the piston and guiding reciprocation of the piston; and a support member seated on a stepped surface of the housing to surround an outside of the cylinder and configured to elastically support the housing and the cylinder, thereby reducing friction while preventing fuel leakage between the piston and the cylinder.

A damper device arranged in a housing space formed between a device main body and a cover member includes a pair of damper bodies each having a plate and a diaphragm and having an enclosed space sealed with gas. A biasing device is provided between the pair of damper bodies arranged facing each other and configured to bias the damper bodies from one side of the device main body and the cover member to the other side of the device main body and the cover member, stay members each extending from an outer peripheral edge portion of each of the damper bodies and brought into contact with other side, and a frame member arranged on one side of the device main body and the cover member and having a stopper portion configured to restrict movement of the damper bodies in the direction of the other side.