Fuel injection nozzle for air-compressing, self-igniting reciprocating internal combustion engines

Claim 1

In a fuel injection nozzle for air-compressing, self-igniting, reciprocating internal combustion engines, comprising a nozzle body comprising a hollow nozzle tip having an inside peripheral surface and valve seating means facing the interior of said nozzle tip and a plurality of nozzle orifices, which have inlet openings in said valve seating means and are open on the outside of said nozzle tip, and a valve needle, which is axially slidably mounted in said nozzle body and nozzle tip and comprises an end portion, which faces said valve seating means and is adapted to cooperate with it so as to open and close said inlet openings, said nozzle tip comprising guiding means formed on said inside peripheral surface and serving to axially guide said valve needle, said valve needle being retractable from said valve seating means to an open position, in which said inside peripheral surface, said valve seating means and said end portion define a plenum chamber, said inside peripheral surface and said valve needle defining around said valve needle between said end portion and said guiding means a clearance space, which is open at said end portion, said nozzle body defining with said valve needle an annular chamber on the side of said guiding means that is opposite to said valve seating means, said nozzle body being formed with a fuel inlet communicating with said annular chamber, said needle valve being formed with an axial bore, which is open on said end portion, and with a transverse bore, which communicates with said axial bore and with said annular chamber regardless of the position of said valve needle, the improvement residing in that said valve seating means comprise a plurality of annular elevations, which surround respective ones of said inlet openings and have surfaces which face and conform to adjacent surface portions of said valve needle and are adapted to cooperate with said adjacent surface portions to open and close said inlet openings, and passage means are provided, through which said clearance space communicates with said annular chamber regardless of the position of said valve needle.