A boot includes an annular body that defines a thru-bore with a thru-bore diameter, and a bore axis. The boot further defines an overall axial length, an exterior, a first axial end, a second axial end, and an aperture that radially extends from the thru-bore to the exterior.

An engine head assembly includes a plurality of fuel injectors each positioned within a fuel injector bore in the engine head, and each being fluidly coupled with a fluid conduit. Each fuel injector includes a valve assembly positioned within a fuel injector case that includes an elongate body having an opening. A filter sleeve having a particle-blocking perforation array structured to block particles is press fit on the fuel injector case to form a fluid flow path from the fluid conduit into the fuel injector case.

An injection hole body has injection holes to inject fuel. A valve body forms a fuel passage with an inner surface of the injection hole body to communicate with inflow ports of the injection holes. The valve body opens and closes the fuel passage by being seated on and unseated from a seating surface of the injection hole body. An inflow port gap distance is a gap between the valve body and the inflow ports along a center axis of the valve body. An inter-injection hole distance is a distance between inflow ports, which are adjacent to each other, among the inflow ports placed around the center axis. The inter-injection hole distance is smaller than the inflow port gap distance in a state where the valve body is unseated from the seating surface and is at a farthest position in its movable range.

An injection hole body has an injection hole to inject fuel for causing combustion in an internal combustion engine. A valve body is unseated from and seated on a seating surface of the injection hole body. The injection hole body and the valve body form a fuel passage therebetween to communicate with an inflow port of the injection hole. The fuel passage is opened and closed by unseating and seating of the valve body. A resilient member generates a resilient force to urge the valve body toward the seating surface. A seat angle is an angle between two straight lines appearing in a cross section of the seating surface, the cross section including a center axis of the valve body. The seat angle is 90 degrees or less.

A filter assembly for a fuel injector is provided. The filter assembly includes a first ring. The first ring includes a plurality of first apertures provided along a circumference thereof. The filter assembly also includes a second ring disposed concentrically with respect to the first ring. The second ring includes a plurality of second apertures provided along a circumference thereof. Each of the plurality of second apertures is disposed misaligned with respect to each of the plurality of first apertures respectively. The filter assembly further includes an actuation mechanism operably coupled to the second ring. The actuation mechanism is adapted to selectively rotate the second ring about an axis with respect to the first ring to, at least partially, align each of the plurality of first apertures with respect to each of the plurality of second apertures respectively to provide an unfiltered flow of a fluid through the filter assembly.

A fuel injector filter is disclosed. The filter may include an inner ring concentrically surrounded by an outer ring. The inner ring may radially extend between an inner ring inner perimeter and an inner ring outer perimeter, and comprise a first port radially extending between the inner ring inner perimeter and the inner ring outer perimeter. The outer ring may radially extend between an outer ring inner perimeter and an outer ring outer perimeter, and comprise a first aperture radially extending between the outer ring inner perimeter and the outer ring inner perimeter. The first aperture may be circumferentially offset from the first port. A filtration channel may radially extend between the inner ring outer perimeter and the outer ring inner perimeter and be configured to impede movement of a particle toward the first port.

A filter for a fuel injection system includes a body that defines a longitudinal axis, a first end face, a second end, an outer surface extending between the first end face and the second end, an inner surface defining an inner chamber closed at the first end face and open at the second end. The body also defines at least one perforated portion formed in the outer surface extending from the outer surface to the inner surface, at least one slot extending axially along the outer surface. The slot is open and is in fluid communication with the first end face and defines an edge along the outer surface. The edge provides fluid communication between the slot and the perforated portion. Additionally, the edge and an inlet channel of the fuel injection system are adapted to define a first filtration zone. The perforated portion defines a second filtration zone.

A filter for a fuel injection system includes a body that defines a longitudinal axis, a first end face, a second end, an outer surface extending between the first end face and the second end, an inner surface defining an inner chamber closed at the first end face and open at the second end. The body also defines at least one perforated portion formed in the outer surface extending from the outer surface to the inner surface, at least one slot extending axially along the outer surface. The slot is open and is in fluid communication with the first end face and defines an edge along the outer surface. The edge provides fluid communication between the slot and the perforated portion. Additionally, the edge and an inlet channel of the fuel injection system are adapted to define a first filtration zone. The perforated portion defines a second filtration zone.

Various embodiments include an adjusting filter for a fluid injector valve comprising: an elongate filter sleeve having an inlet and an outlet; and a filter insert. The filter sleeve includes a filter accepting section at the inlet, a press-fit section, a centring section at the outlet, and a spring engaging surface surrounding the outlet. The press-fit section is arranged between the filter accepting section and the centring section. The filter insert is arranged in the filter accepting section. The filter accepting section has an outer diameter smaller than an outer diameter of the press-fit section. The centring section has an outer diameter smaller than the outer diameter of the press-fit section.

A boot in a fuel system includes a boot wall having a window formed therein receiving an electrical connector of a fuel injector, and a filter attached to the boot wall. An air gap is defined between the fuel injector and the boot, and a filtered air flow path extends through the filter to the air gap. The boot may be implemented in an assembly of a fuel injector and a double-walled fuel conduit such as in a fuel system for an internal combustion engine.