A pump body of a high-pressure pump includes a pressure chamber formed in a deep portion of a cylinder. The pump body closes the pressure chamber on a side opposite to a plunger. The plunger reciprocates within the cylinder to vary a volume of the pressure chamber. The large-diameter portion provided at an end of the plunger on a side protruding to the pressure chamber has an outside diameter larger than an inside diameter of the cylinder and smaller than an inside diameter of the pressure chamber. In this case, the large-diameter portion is engaged with a step portion between the cylinder and the pressure chamber in a state before attachment of the high-pressure pump to an internal combustion engine. Accordingly, separation of the plunger from the cylinder is avoidable.

A fuel system for an internal combustion engine includes a nozzle, a fuel pump, a spill valve assembly, and a pumping control unit. The spill valve assembly includes a first spill valve and a second spill valve fluidly in parallel between a plunger cavity in the fuel pump and a low pressure space. A pumping control unit commands closing of the first spill valve and then the second spill valve to adjust the spill valve assembly to start pressurization in the fuel pump, and commands opening the first spill valve to end pressurization in the fuel pump. A pumping duration is determined based on a timing of the commanded closing of the second spill valve and a timing of the commanded opening of the first spill valve.

Disclosed is an anti-tampering device including a threaded element having a thread defining a screwing axis and an engaging surface for engagement with a driving tool, and a protection body for preventing the driving tool from engaging the engaging surface. The protection body is coupled to the threaded element so that they are mutually blocked in a direction parallel to the screwing axis and free to spin around the screwing axis.

A fuel system for an internal combustion engine includes a nozzle, a fuel pump, a spill valve assembly, and a pumping control unit. The spill valve assembly includes a first spill valve and a second spill valve fluidly in parallel between a plunger cavity in the fuel pump and a low pressure space. A pumping control unit commands closing of the first spill valve and then the second spill valve to adjust the spill valve assembly to start pressurization in the fuel pump, and commands opening the first spill valve to end pressurization in the fuel pump. A pumping duration is determined based on a timing of the commanded closing of the second spill valve and a timing of the commanded opening of the first spill valve.

Provided is a high-pressure fuel supply pump capable of fixing a cylinder to a pump body with excellent sealability in a simple structure even at a high fuel pressure. A high-pressure fuel supply pump including a pump body in which a pressurizing chamber is formed, and a cylinder inserted into a hole formed in the pump body and formed in a cylindrical shape, the high-pressure fuel supply pump including: a protrusion disposed at an end portion of the pump body opposite to the pressurizing chamber, formed from an outer peripheral side to an inner peripheral side with respect to an inner peripheral surface opposite to an outer peripheral surface of the cylinder, and protruding toward the cylinder, wherein the protrusion is formed so as to protrude to a side opposite to the pressurizing chamber with respect to a flat portion of the end portion of the pump body, and the protrusion is formed so as to support the cylinder from a side opposite to the pressurizing chamber.

Provided is a high-pressure fuel supply pump capable of fixing a cylinder to a pump body with excellent sealability in a simple structure even at a high fuel pressure. A high-pressure fuel supply pump including a pump body in which a pressurizing chamber is formed, and a cylinder inserted into a hole formed in the pump body and formed in a cylindrical shape, the high-pressure fuel supply pump including: a protrusion disposed at an end portion of the pump body opposite to the pressurizing chamber, formed from an outer peripheral side to an inner peripheral side with respect to an inner peripheral surface opposite to an outer peripheral surface of the cylinder, and protruding toward the cylinder, wherein the protrusion is formed so as to protrude to a side opposite to the pressurizing chamber with respect to a flat portion of the end portion of the pump body, and the protrusion is formed so as to support the cylinder from a side opposite to the pressurizing chamber.

A pulsation damper includes an upper diaphragm, a lower diaphragm configured to form a sealed space having a predetermined pressure with the upper diaphragm, in which an inert gas is filled; and a deformation suppressing member formed of an elastic material, and comprising an inner cylindrical portion, and an extension portion extending from a center portion on an outer peripheral surface of the inner cylindrical portion such that the extension portion extends outward from a center axis of the inner cylindrical portion, wherein the deformation suppressing member is arranged inside the sealed space such that an outer periphery of the extension portion abuts against inner walls of the upper diaphragm and the lower diaphragm.

A pulsation damper includes an upper diaphragm, a lower diaphragm configured to form a sealed space having a predetermined pressure with the upper diaphragm, in which an inert gas is filled; and a deformation suppressing member formed of an elastic material, and comprising an inner cylindrical portion, and an extension portion extending from a center portion on an outer peripheral surface of the inner cylindrical portion such that the extension portion extends outward from a center axis of the inner cylindrical portion, wherein the deformation suppressing member is arranged inside the sealed space such that an outer periphery of the extension portion abuts against inner walls of the upper diaphragm and the lower diaphragm.

A fuel injection pump includes a plunger, a plunger barrel which supports the plunger, a body which houses the plunger and the plunger barrel, a plate which covers an opening formed on the body, a control lever turnably attached near the plate, and an adjuster bolt which abuts against the control lever to restrict turn of the control lever and is supported by a stay disposed on the plate.

The present disclosure relates to high-pressure fuel pumps and the teaching may be applied to pumps in which a pump piston, by means of which a fuel is acted on with a high pressure, is guided in a guiding sleeve. In some embodiments, a high-pressure fuel pump may include: a housing having a housing recess; a pump piston for pressurizing a fuel; and a guiding sleeve arranged in the housing recess and guiding the pump piston. The guiding sleeve is connected to the housing recess with a materially engaging connection.