Abstract: An engine fuel injector body is assembled using a furnace brazing method to provide structural and hermetic internal joints at interior locations with minimum size and processing. The method of assembling an injector with such an internal hermetic and structural joint may include the steps of providing an annular body member with an annular inner recess having an inner cylindrical surface, forming an annular end recess adjoining the cylindrical surface, fitting a tubular member into the inner recess of the body member with an outer surface of the tubular member engaging the cylindrical surface of the inner recess, placing a brazing ring in the end recess of the body member adjacent the tubular member, and furnace brazing the members together to form the internal hermetic and structural joint. Additional joints may be joined during the same brazing step.

Abstract: A method of assembly of a fuel injector having a valve plunger reciprocable in a guide tube for movement from a closed position engaging a valve seat to an open position engaging a valve stop by energizing of a solenoid coil to move the plunger against a biasing spring, wherein the method includes setting the valve stop at a position effective to establish the desired valve stroke, and fixing the valve stop to the guide tube by first laser spot welding the valve stop in the guide tube to fix the position of the valve stop without changing the set gap, and then laser seam welding the valve stop in the guide tube at an axial location beyond the spot welds, relative to a plunger-engagable end of the valve stop, to provide a hermetic seal around the valve stop.

Abstract: A fuel injector for an engine includes a continuous endoskeletal injector tube enclosing an imperforate continuous passage for fuel flow from an inlet end to an outlet end of the tube. A valve seat, injection valve, tubular magnetic pole, biasing spring and adjusting sleeve are mounted within the tube, optionally with other elements, all being exposed to fuel in the passage defined by the tube. A solenoid coil and a magnetic body together with mounting components and seals are mounted on the exterior of the tube where they are protected from exposure to the fuel, which is restricted to passage within the continuous tube. The body, pole and armature form a magnetic flux concentrating path operative to attract the armature to the pole and open the valve when the coil is energized. The solenoid coil may be preassembled with its connector in a body forming a separate coil assembly for subsequent installation on the injector tube.

Abstract: An injector fuel injection valve is guided at the lower end by a plastic valve guide mounted in a nozzle containing a valve seat engagable by the valve element. The valve guide includes inwardly protruding annularly spaced ribs having inner guide surfaces and defining spaced flow channels. The guide surfaces engage the circular or spherical exterior of the valve element to guide the element to properly aligned seating against the conical valve seat. The plastic or polymeric valve guide is preferably molded in place within the cup shaped metal nozzle but, if desired, the valve guide may be separately molded and subsequently inserted or snapped in place within the nozzle. A second plastic valve guide may be provided for guiding the upper end of an associated armature.