A pressurized fuel system for an engine includes a fuel pump in a pump protection device structured to drain pressurized fuel from a common rail to provide fuel flow through the fuel pump that limits cavitation. The device includes a valve mechanism having a first valve and a second valve that are movable to an open position and a closed position respectively, in response to valve opening and valve closing rail pressures. The active pressure range of the device may be a medium pressure range.

A coil assembly in a fuel injector includes a magnetic core and; a winding wound around the core, the winding being overmoulded and forming a cylindrical overmoulding. An axial blind hole extends towards the interior of the coil assembly from a first surface to a distal end, the blind hole being suitable for housing at least one spring for loading a magnetic armature. The coil assembly is provided with a degassing hole passing through the core and the overmoulding from the blind axial hole to an axial outer cylindrical surface, the degassing hole being provided in the magnetic core and having a restriction that is arranged in a first section that is proximal to the blind axial hole.

An object is to suppress cavitation generated at a distal end portion of a seat face when a valve body and a seat portion collide with each other. In a relief valve of a fuel pump, an intersection between the seat face and a flow channel hole is formed at a position more distant than the seat portion formed of the valve body in a valve closing state and the seat face in order to suppress generation of cavitation bubbles when the valve body improves and releases high-pressure fuel.

A method for generating cavitation resistance in a liquid, a portion of which can be in contact with a surface is disclosed. The disclosed method can be carried out by pressure-treating the liquid, the liquid portion in contact with the surface, and/or the surface for a sufficient time to develop resistance to cavitation. The disclosed method can be carried out when the surface is made of a material having a surface roughness that is greater than the rc of the liquid. Suitable surfaces include borosilicate glass, drawn glass, copper, lead, steel, cast iron, metal alloys and concrete. The surfaces can be ship and boat propeller surfaces, the interior of fuel lines and fuel storage containers or any other surface where cavitation can occur.

The subject matter of this specification can be embodied in, among other things, a fluid control device that includes a housing defining a plunger cavity in fluid communication with a fluid inlet and a fluid outlet, a valve having a shaft having a first end and a second end, and a stopper at the first end configured to block a fluid circuit between the fluid inlet and the fluid outlet in a first configuration of the inlet control valve and connect the fluid circuit in a second configuration of the inlet control valve, and a plunger configured for axial movement within the plunger cavity, defining a shaft cavity having an inner wall extending from an enclosed end to an open end in fluid communication with the fluid outlet, and configured to accommodate axial movement of the shaft within the shaft cavity.

Provided is a high-pressure fuel injection pipe with a connection head which achieves an improvement in outer-surface cleanliness and prevention of a decrease in axial force and fastening strength. The pipe having, at a connection end of a narrow-diameter thick-wall steel pipe having a rust-inhibiting coating applied to an outer surface of the pipe, the connection head composed of a spherically-shaped seat surface, an annular flange, and a conical surface and having an outside peripheral surface forming formed into seat surface in a truncated conical shape or truncated arc shape for a mating seat; and a washer fitting in a neck lower part of the connection head and having a rust-inhibiting coating applied to an outer surface of the washer, wherein a contact part between the neck lower part of the connection head and an end part of the washer has a metal-to-metal contact structure without having the rust-inhibiting coating.

A liquid pump applicable in a fuel system such as a common rail fuel system includes a valve assembly having a valve stack with axially aligned components, dead volume, and vapor-distributing flow channels, for cavitation mitigation. An inlet valve meters a flow of liquid into the pump for pressurization by a plurality of reciprocating plungers operated by way of a rotating camshaft.

A needle type fuel injector has a needle control chamber at a pressure subject to a control valve in a control valve chamber which in an opening phase is lifted from its seat to expose the control valve chamber, connecting passage, and needle control chamber to a low pressure drain and in a closing phase is urged against the seat to isolate the control valve chamber, connecting passage, and needle control chamber from the drain. The potential for cavitation at high fuel injection pressure is reduced by throttling the flow of fuel past the control valve seat when the control valve opens, thereby maintaining sufficient back pressure in the control valve chamber and upstream connecting passages.

A method of refurbishing a fuel injector body valve seat. The method includes removing a poppet valve from the valve bore guide, machining the bore and valve seat to remove cavitation, machining to create an undercut a the stress riser, nitriding the valve bore guide and radiusing fuel passage to a sufficient depth to restore hardness thereto.

A fuel injector includes control valve for controlling fuel pressure in a control chamber. The control valve includes a valve seat; and a valve member having a valve face for cooperating with the valve seat to control fuel pressure in the control chamber. A return line is provided for returning fuel from the control chamber. An armature connected to the valve member and an actuator is provided for actuating the armature. The armature is disposed in an armature chamber. A deflector is provided in the armature chamber to form a first sub-chamber and a second sub-chamber. The first and second sub-chambers are in fluid communication with each other via a first aperture. A pressure differential is established between the first and second sub-chambers when the valve face lifts from the valve seat promoting the flow of fuel from the second sub-chamber into the first sub-chamber through the first aperture.