DUAL-FUEL INJECTOR, DUAL-FUEL SYSTEM, INTERNAL COMBUSTION ENGINE AND METHOD FOR OPERATING THE SAME

摘要

A dual-fuel injector for a cylinder (2) of an internal combustion engine (1), with at least one first nozzle valve (7), via which a first fuel, in particular diesel, is introducible into a combustion chamber (5) of the respective cylinder (2), and with at least one second nozzle valve (9), via which a second fuel, in particular methanol, is introducible into the combustion chamber (5) of the respective cylinder (2), wherein in the region of the or each second nozzle valve (9) a nozzle needle of the respective second nozzle valve (9) is guided in a needle guide of the same, wherein the needle guide defines a needle fuel chamber, which is suppliable with the second fuel with a defined fuel pressure via a supply line, at least in sections, wherein in the region of the or each second nozzle valve (9) the needle guide of the respective second nozzle valve (9) is suppliable with a sealing and lubricating oil in order to avoid, on the one hand, the second fuel escaping into the surroundings via the needle guide and on the other hand lubricate the respective nozzle needle in the needle guide, wherein the or each second nozzle valve (9) is assigned a switching valve (18), which supplies the respective needle fuel chamber of the respective second nozzle valve (9) with the second fuel as a function of an injection cycle of the respective cylinder (2) via the supply line, so that the fuel pressure of the second fuel is present in the needle fuel chamber as a function of the injection cycle, and wherein the needle guide of the respective second nozzle valve (9) defines a needle lubricating chamber suppliable by the sealing and lubricating oil at least in sections, which has a distance from the respective needle fuel chamber that is dimensioned in such a manner that in particular when in the respective needle fuel chamber the fuel pressure of the second fuel as a function of the injection cycle is present, the second fuel does not enter the region of the needle lubricating chamber.