The invention relates to a fuel injector, in particular a common rail injector, for injecting fuel into a combustion chamber of an internal combustion engine.
A fuel injector of this kind, in particular a common rail injector, is known from DE 10 2009 001 704 A1 and from DE 10 2014 209 997, which is not a prior publication. A high-pressure space is formed within a nozzle body of the injector housing. Arranged in the injector body there is furthermore a valve piece, which accommodates a nozzle needle end facing away from an injection opening. In this case, the nozzle needle is subjected to a force in the closing direction by means of a return spring, wherein the nozzle needle interacts with a nozzle body seat and thereby opens and closes at least one injection opening. Moreover, the nozzle needle has a radially encircling offset, on which a first sleeve-shaped supporting element rests, wherein the first sleeve-shaped supporting element is subjected to a force in the closing direction of the nozzle needle by the return spring. In this case, the return spring is supported by means of its other end against a second sleeve-shaped supporting element, which is arranged so as to face the end of the nozzle needle remote from the combustion chamber.
To limit the maximum opening stroke of the nozzle needle, the mutually facing stop surfaces of the first sleeve-shaped supporting element and of the second sleeve-shaped supporting element are at a distance from one another, wherein the distance 35 in the closed position of the nozzle needle defines the maximum opening stroke.
In the open position of the nozzle needle, the stop surface of the first sleeve-shaped supporting element rests against the stop surface of the second sleeve-shaped supporting element. This can lead to hydraulic adhesion of the two stop surfaces. This delays the nozzle closing movement, resulting in imprecise injection.