During a pressurization stroke of a high-pressure pump, a cylinder inner wall and a plunger receive a fuel pressure from the pressurization chamber. Meanwhile, an upper housing does not receive the fuel pressure from the pressurization chamber, so that its thickness can be made thin. A cylinder is comprised of a bottom portion, a cylindrical portion and a large-diameter cylindrical portion. When inserting the large-diameter cylindrical portion into a large engaging hole, the bottom portion and the cylindrical portion are not brought into contact with a lower housing. A high liquid-tightness between the bottom portion, the cylindrical portion and a small engaging hole can be ensured.

During a pressurization stroke of a high-pressure pump, a cylinder inner wall and a plunger receive a fuel pressure from the pressurization chamber. Meanwhile, an upper housing does not receive the fuel pressure from the pressurization chamber, so that its thickness can be made thin. A cylinder is comprised of a bottom portion, a cylindrical portion and a large-diameter cylindrical portion. When inserting the large-diameter cylindrical portion into a large engaging hole, the bottom portion and the cylindrical portion are not brought into contact with a lower housing. A high liquid-tightness between the bottom portion, the cylindrical portion and a small engaging hole can be ensured.

A common rail system for a fuel injection system of an internal combustion engine, the common rail system comprising: a high pressure pump for receiving fuel from a fuel tank; at least one fuel injector for delivering fuel to the internal combustion engine; a common rail for receiving fuel from the high pressure pump through a flow path of the common rail system that connects the high pressure pump to the common rail, the common rail comprising a fuel reservoir in fluid communication with a common rail inlet and in fluid communication with the one or more fuel injectors; and a filter provided in the flow path. The filter is configured to filter fuel so as to prevent particulate matter from entering the common rail. The common rail system comprises only one filter.

A common rail system for a fuel injection system of an internal combustion engine, the common rail system comprising: a high pressure pump for receiving fuel from a fuel tank; at least one fuel injector for delivering fuel to the internal combustion engine; a common rail for receiving fuel from the high pressure pump through a flow path of the common rail system that connects the high pressure pump to the common rail, the common rail comprising a fuel reservoir in fluid communication with a common rail inlet and in fluid communication with the one or more fuel injectors; and a filter provided in the flow path. The filter is configured to filter fuel so as to prevent particulate matter from entering the common rail. The common rail system comprises only one filter.

A tool is disclosed for installing a roller tappet in a bore of the cylinder head of an internal combustion engine. The tool includes an elongated body and a connection head arranged at one end of the elongated body and configured to be at least in part inserted into an opening of the roller tappet. The tool further includes at least one reversible constraining element of the connection head to the roller tappet.

A damper cup houses a pulsation damper of a fuel pump such that the damper cup defines a fuel volume together with a fuel pump housing of the fuel pump. The damper cup includes a sidewall which is annular in shape and which extends along a damper cup axis from a sidewall first end to a sidewall second end. The damper cup also includes an end wall which closes the sidewall second end, wherein the sidewall includes a support shoulder which is transverse to the damper cup axis and which is a segment of an annulus extending uninterrupted about the damper cup axis from a shoulder first end to a shoulder second end such that the shoulder first end and the shoulder second end are separated from each other by a gap which is uninterrupted.

A valve arrangement for a high pressure pump includes a pump housing with a depression, and a valve housing configured to be inserted in the depression, and a clamping disc. The valve housing has at least one radial projection with a first axial boundary surface and a second axial boundary surface arranged opposite the first axial boundary surface, wherein the clamping disc extends radially over the radial projection of the valve housing and has a third axial boundary surface that corresponds with the second axial boundary surface of the valve housing. On the circumferential side, the clamping disc has a thread that can be screwed into a thread on the inner side of the depression to brace the valve housing onto the first boundary surface.

A valve arrangement for a high pressure pump includes a pump housing with a depression, and a valve housing configured to be inserted in the depression, and a clamping disc. The valve housing has at least one radial projection with a first axial boundary surface and a second axial boundary surface arranged opposite the first axial boundary surface, wherein the clamping disc extends radially over the radial projection of the valve housing and has a third axial boundary surface that corresponds with the second axial boundary surface of the valve housing. On the circumferential side, the clamping disc has a thread that can be screwed into a thread on the inner side of the depression to brace the valve housing onto the first boundary surface.

A mechanical system, comprising a support element, a pin extending along a first axis and comprising two opposite ends, each adapted to be fitted in the support element for radial retention of the pin relative to the first axis, and a roller element movable in rotation relative to the pin around the first axis. The mechanical system includes two ribs resting on either side of the ends for axial retention of the pin along the first axis. The mechanical system can be integrated into either an injection pump or a valve actuator.

A mechanical system, comprising a support element, a pin extending along a first axis and comprising two opposite ends, each adapted to be fitted in the support element for radial retention of the pin relative to the first axis, and a roller element movable in rotation relative to the pin around the first axis. The mechanical system includes two ribs resting on either side of the ends for axial retention of the pin along the first axis. The mechanical system can be integrated into either an injection pump or a valve actuator.