Abstract: A fuel injection system for an internal combustion engine and having a high-pressure fuel pump and a fuel injection valve for each engine cylinder. A first electrically actuated control valve controls a connection of the pump working chamber to a low-pressure region and a second electrically actuated control valve controls a connection of a control pressure chamber of the fuel injection valve to a relief region. A pressure reservoir is filled by the high-pressure fuel pump and from which fuel can be withdrawn in order to execute a fuel injection with the fuel injection valve independent of the delivery from the high-pressure fuel pump. The connection between the fuel pump and the pressure reservoir and injection valve contains a coupling device having a piston acted on at one end by the pressure prevailing in the pressure reservoir acted on at the other end by the pressure prevailing in the connection.

Abstract: A fuel injection system for an internal combustion engine, having a fuel injector supplied with fuel from a high-pressure fuel source and including an injection valve member for opening or closing injection openings and a low-pressure circuit with a prefeed pump which pumps fuel from a fuel tank. Partial return fuel quantities, depressurized to the prefeed pressure of the prefeed pump, are delivered to the low-pressure circuit by pressure boosters or by fuel injectors inside an infeed portion via returns.

Abstract: A servo-valve for a fuel injector equipped with a pressure booster whose working chamber is separated from a differential pressure chamber by a booster piston in which an actuator can connect a control chamber to a first low-pressure return and the differential pressure chamber can be connected to a second low-pressure return or to a return system in which the returns are connected to each other. A first servo-valve piston has a first sealing seat, and a second piston, embodied as a sealing sleeve, is accommodated on the first servo-valve piston and, together with a valve housing, constitutes a second sealing seat. When the pressure in the control chamber is relieved, this second sealing seat is closed with a shorter stroke, sooner than the first sealing seat. When the control chamber is subjected to pressure, the second sealing seat opens only after the first sealing seat is closed.

Abstract: A fuel injector having an injection valve connected to a high-pressure source and a control valve including a control piston guided in a valve body and comprising a pressure piston section having a first pressure surface guided in a bush and a control piston section with a sliding seal that has a control edge; the bush is contained in a pressure chamber of the valve body. In a first valve position, a sealing seat of the control piston disconnects a valve chamber from a low-pressure/return system and in a second valve position, the control edge of the control piston disconnects the pressure chamber from the valve chamber; in the second valve position, a connection is simultaneously produced between the valve chamber and the low-pressure/return system, thus initiating an actuation of the fuel injection valve. The control piston section with the control edge is guided in a control cylinder that is contained in the pressure chamber of the valve body and is separate from the bush.

Abstract: A fuel injector for injecting fuel into the combustion chamber of an internal combustion engine is equipped with a pressure booster that has a working chamber continuously connected to a common rail, and has a differential pressure chamber, which a piston part separates from the working chamber. The fuel injector also has an injection valve member. To actuate the fuel injector, a valve having a control valve in the form of a servo valve and an actuating valve that actuates this control valve. The multistage valve controls both the pressure booster and the injection valve member. The control valve and the actuating valve are hydraulically coupled to each other and different outlet throttles can be opened and closed in order to achieve different opening speeds of a servo valve piston.

Abstract: A fuel injector having a pressure booster whose booster piston separates a working chamber, which is continuously acted on with fuel by means of a pressure source, from a differential pressure chamber that can be pressure-relieved; a pressure change in the differential pressure chamber occurs via an actuation of a servo-valve whose control chamber can be pressure-relieved by an on/off valve that also opens or closes a hydraulic connection of the differential pressure chamber to a first return on the low-pressure side. In the deactivated state of the pressure booster, a first sealing seat seals a return on the low-pressure side off from a high-pressure region of the servo-valve, which region is comprised of the control chamber, a first hydraulic chamber, and a second hydraulic chamber.

Abstract: A method for triggering a fuel injector via an on/off valve and a control valve that actuates it. The fuel injector has a pressure booster whose piston parts separate a working chamber from a differential pressure chamber. Via a compression chamber of the pressure booster, a nozzle chamber of the fuel injector can be acted on with highly pressurized fuel. The working chamber of the pressure booster communicates continuously with a common rail. During the main phase in which fuel is injected into the combustion chamber of an internal combustion engine, the control valve that actuates the on/off valve is triggered once or multiple times so that the maximum pressure level occurring at the combustion chamber end of a one-part or multipart injection valve member falls below the maximum achievable pressure level.

Abstract: A fuel injection system for an internal combustion engine including a fuel injector which can be subjected to fuel at high pressure and is actuatable via a metering valve device by which the pressure in a pressure booster control chamber is controllable such that the pressure in a pressure booster pressure chamber, defined by a pressure booster piston, that can be filled with fuel from the high-pressure fuel source via a filling path in which a check valve is disposed and that is in communication with an injection valve member pressure chamber, is increased by the pressure booster piston such that an injection valve member opens for injecting fuel, whereupon fuel is positively displaced out of a damping chamber via a damping path, in which a damping throttle is disposed.

Abstract: A fuel injector for injecting fuel into a combustion chamber of an internal combustion engine, including a pressure booster, whose booster piston separates a work chamber, subjected to fuel via a pressure reservoir, from a pressure-relievable differential pressure chamber. A pressure change in the differential pressure chamber is effected via an actuation of a servo valve, which opens or closes a hydraulic connection of the differential pressure chamber to a first low-pressure-side return. The servo valve has a piston guided between a control chamber and a first hydraulic chamber. On this servo valve piston, a hydraulic face that positions the servo valve piston constantly in the opening direction when system pressure is applied and a first sealing seat that closes or opens a low-pressure-side return are embodied.

Abstract: A fuel injection system for an internal combustion engine and having a high-pressure fuel pump and a fuel injection valve for each engine cylinder. A first electrically actuated control valve controls a connection of the pump working chamber to a low-pressure region and a second electrically actuated control valve controls a connection of a control pressure chamber of the fuel injection valve to a relief region. A pressure reservoir is filled by the high-pressure fuel pump and from which fuel can be withdrawn in order to execute a fuel injection with the fuel injection valve independent of the delivery from the high-pressure fuel pump. The connection between the fuel pump and the pressure reservoir and injection valve contains a coupling device having a piston acted on at one end by the pressure prevailing in the pressure reservoir acted on at the other end by the pressure prevailing in the connection.

Abstract: A fuel injection device for an internal combustion engine, having two valve elements each having a hydraulic control surface acting in the closing direction and associated with a hydraulic control chamber. A control valve influences the pressure in the control chamber, and loading devices act on the valve elements in the opening direction. The valve elements react at different hydraulic opening pressures prevailing in the control chamber. The control valve is able to set at least three different pressure levels in the control chamber: all of the valve elements are closed at a comparatively high pressure level; one valve element is open at a medium pressure level; and all of the valve elements are open at a comparatively low pressure level.

Abstract: A servo-valve for a fuel injector equipped with a pressure booster whose working chamber is separated from a differential pressure chamber by a booster piston in which an actuator can connect a control chamber to a first low-pressure return and the differential pressure chamber can be connected to a second low-pressure return or to a return system in which the returns are connected to each other. A first servo-valve piston has a first sealing seat, and a second piston, embodied as a sealing sleeve, is accommodated on the first servo-valve piston and, together with a valve housing, constitutes a second sealing seat. When the pressure in the control chamber is relieved, this second sealing seat is closed with a shorter stroke, sooner than the first sealing seat. When the control chamber is subjected to pressure, the second sealing seat opens only after the first sealing seat is closed.

Abstract: A fuel injector with a pressure booster supplied with fuel at high pressure. A work chamber of the pressure booster is separated from a differential pressure chamber via a booster piston. The pressure relief and the subjection to pressure of the differential pressure chamber are effected via a switching valve which communicates with the differential pressure chamber via a control line. A pressure chamber on an injection valve member communicates with a compression chamber of the pressure booster via a pressure chamber supply line. The switching valve is embodied as a direct-switching 3/2-way valve, whose valve needle is pressure-balanced and has both a sliding seat and a slide seal.

Abstract: A servo valve for actuating a pressure booster of a fuel injector, the pressure booster having a work chamber separated by a booster piston from a differential pressure chamber and the pressure change in the differential pressure chamber of the pressure booster is effected via the servo valve, via switching valve. The control chamber of the servo valve can both be made to communicate with a high-pressure source and pressure-relieved into a low-pressure-side return, and for generating a fast closing motion at the valve piston, a pressure shoulder acting in the closing direction of the valve piston is embodied between the control chamber and the hydraulic chamber, and control edges without a common opening phase are embodied on the valve piston.

Abstract: A fuel injector for injecting fuel that is at high pressure into a combustion chamber of an internal combustion engine has an injection valve member triggered by an actuator and a coupler chamber; the actuator acts on the injection valve member and the injection valve member opens or closes at least one injection opening. The coupler chamber is located on the side of the actuator diametrically opposite the injection valve member; and the coupler chamber is filled with fuel that is at system pressure when the injection opening is closed.

Abstract: A fuel injector with a direct needle control for an internal combustion engine, having an actuator, a hydraulic booster, and a nozzle needle guided in a nozzle body and acting on a nozzle needle sealing seat. The hydraulic booster includes a booster piston connected to the actuator and a nozzle needle booster piston connected to the nozzle needle; a booster chamber in the form of an actuator coupler chamber is associated with a pressure surface of the actuator booster piston; and depending on the pressure in the actuator coupler chamber, the nozzle needle is lifted away from the nozzle needle sealing seat, thus initiating an injection. In addition to the actuator booster piston, a control element is provided that is able to execute a stroke motion, is hydraulically coupled to the actuator coupler chamber by means of a first control surface, and is associated with a control chamber by means of a second control surface.

Abstract: A fuel injection system for internal combustion engines, having a fuel injector that can be acted upon by a high-pressure fuel source includes a pressure booster, which contains a movable boosting element dividing a work chamber which can be made to communicate with the high-pressure source via a high-pressure line from a high-pressure chamber that acts on the fuel injector. The high-pressure from chamber is variable by filling and evacuating a differential pressure chamber of the pressure booster. A filter element is received in a line portion that branches off from the high-pressure line and is upstream of flow connections for filling the differential and high pressure chambers.

Abstract: A fuel injection apparatus for injecting fuel into the combustion chambers of an internal combustion engine. includes a high pressure accumulator, a pressure booster, and a metering valve. The pressure booster includes a working chamber and a control chamber that are separated from each other by an axially movable piston. A pressure change in the control chamber produces a pressure change in a compression chamber that acts on a nozzle chamber via a fuel inlet. The nozzle chamber encompasses a nozzle needle. A nozzle spring chamber that acts on the injection valve element can be filled on the high-pressure side via a line that leads from the compression chamber and contains an inlet throttle restriction. On the outlet side, the nozzle spring chamber is connected to a chamber of the pressure booster via a line that contains an outlet throttle restriction.

Abstract: The invention relates to a device for injecting fuel into a combustion chamber of an internal combustion engine, and which includes a fuel injector which can be acted upon by fuel at high pressure via a high-pressure source and is actuatable via a metering valve. Associated with the injection valve member is a damping element, which is movable independently of it and defines a damping chamber. The damping element has at least one overflow conduit for connecting the damping chamber to a further hydraulic chamber.

Abstract: A fuel injection system of an internal combustion engine has, depending on the number of cylinders, at least one local pump element, assigned to each injector, of a unit fuel injector or a pump-line-nozzle system for compressing the fuel. The injector and/or the supply line to the injector form a local pressure reservoir chamber.