The teachings of the present disclosure describe an injector having an injector housing, an actuator, and a nozzle needle, wherein the actuator is arranged in an actuator space of the injector housing. The injector may include a control piston bore in the injector housing, in which a control piston is arranged, a leakage pin bore between the actuator space and the control piston bore, and a leakage pin coupling the control piston to the actuator, the leakage pin arranged in the leakage pin bore. The control piston may be hydraulically connected to the nozzle needle in order to open or close an outlet opening of the injector housing. The injector may include a high pressure line configured to convey a fuel under pressure to the nozzle needle and a feedline in the injector housing connecting the leakage pin bore to the high pressure line.

A piezo injector includes a piezo actuator arranged in an actuator chamber and a valve plunger arranged in a valve plunger bore and having a first end face facing the piezo actuator. The valve plunger is arranged between a first control chamber defined by a valve plunger bore portion delimited by the first end face and a spring chamber formed by a valve plunger bore portion opposite the first control chamber. A second control chamber is delimited by a second face of a nozzle needle and a sleeve guided by the nozzle needle. A leakage pin is arranged in a leakage pin bore between the piezo actuator and the first end face of the valve plunger. The leakage pin bore is formed in an intermediate plate arranged on a side of a control plate facing the piezo actuator, the valve plunger bore being formed in said control plate.

A fuel injection valve includes a body including a first chamber that supplies fuel of a first pressure, a second chamber that supplies fuel of a second pressure, and an injection hole, a valve chamber member including a valve chamber connectable to the first chamber and the second chamber, a control chamber member including a control chamber connectable to the first chamber, a needle pressed by pressure of fuel in the control chamber in a direction that causes fuel injection from the injection hole to stop, an actuator, a valve element that selectively connects the first chamber, second chamber, and the valve chamber according to the actuator extending and contracting, and a transmission mechanism that when the actuator extends, transmits the force to the needle as a force in a direction that causes fuel to be injected from the injection hole.

A piezo injector with an actuator chamber, in which a piezo actuator is arranged, includes an upper section (the injector body) and a lower section (the nozzle body). The piezo injector also has a control piston bore formed in the nozzle body, wherein a control sleeve, in which a control piston is received, is arranged in the control piston bore. The control sleeve seals against an intermediate plate with a first front face facing the piezo actuator. The control piston has a first side facing the piezo actuator, wherein the first front face of the control piston and the section of the control sleeve facing the piezo actuator form a first control chamber.

The invention relates to an actuator (1) comprising a housing (8), a coil (29) and an armature (2) which interacts with a tappet (30) and a spring, the armature plate (3) thereof being arranged to lie opposite an armature counterpiece (16), and said actuator (1) comprising at least one magnetostrictively-active component. According to the invention, an actuator (1) is provided with which large actuating paths can be travelled at high actuating forces. This is achieved by the actuator (1) additionally being designed to act as a solenoid.

A system and method are provided for monitoring a pressure of fuel supplied to the fuel injector, and providing a control input voltage to the piezostack in response to the pressure to cause the injector to provide a fuel injection having a desired shape. In the system and method, providing a control input voltage includes applying a model-based algorithm to the pressure to determine the control input voltage.