Robert Boschgmbh

Katsuoki Itoh

Iwan Komaroff

Rudolf Heinz

Winfried Moser

Christoph Franke

Friedrich Boecking

Karl Hofmann

Dietrich Trachte

Kurt Seifert

Gilbert Moersch

Guenter Lewentz

Christoph Treutler

Paul Fussner

Reiner Schuetz

Hans-Jorg Vogtmann

Bernd Dittus

Wilhelm Vogel

Hans-Friedemann Kober

Gerhard Auwaerter

In a fuel injection nozzle having a nozzle body, a nozzle needle that is displaceable in the nozzle body, a piezoelectric actuator that is connected to the nozzle needle, and a compensation piston on which the piezoelectric actuator is braced and which protrudes into a compensation chamber that is filled with a fluid, where the compensation chamber communicates with a supply volume through an inlet of small cross section, a simpler design is to be attained. To that end, it is provided that the supply volume is subjected to variable pressure making it possible to dispense with a separate restoring spring for the nozzle needle.

Fuel injection nozzle

A fuel injection system in which a high pressure fuel reservoir is provided for supplying fuel injection valves. The valves are electrically controlled and are supplied in a correspondingly controlled fashion with fuel for injection from the high pressure fuel reservoir. The fuel injection valves are connected directly with their housings to the high pressure fuel reservoir in order to avoid the interposition of fuel lines.

Fuel injection system

A fuel injection for internal combustion engines, having a valve member which is guided so that it moves axially in a valve body and uses a sealing face provided on a combustion chamber end to open and close an injection opening on the valve body. A piezoelectric actuator includes a piezoelectric stack, which changes in length with the action of a control voltage, is coupled to the combustion chamber end of the valve member to actuate the valve member. In order to prevent an interference with a precise adjustment motion of the valve member of an unwanted length change in the piezoelectric stack, a clamping device is provided which fixes the end of the piezoelectric stack remote from the valve member in its axial position during the injection phase of the fuel injection valve, and permits an axial compensation for play at the piezoelectric stack during an injection pause.

Clamping device for a piesoelectric actuator of a fuel injection valve

A fuel injection valve for internal combustion engines with a valve member which is displaced in a bore in a valve body by the fuel pressure, counter to the action of a closing spring. The valve body has at a combustion-space end, a valve head which on a side which faces the valve body is arranged a sealing surface which interacts with a valve seat provided on the combustion-space end of the valve body, forming a sealing cross section, and including injection apertures which permit a flow of fuel from a pressure space in the valve body to the combustion space of the internal combustion engines and has an aperture cross section which can be varied as a function of the stroke of the valve member. According to the invention, those parts which seal off the injection valve from the outside and those parts which form the aperture cross section of the injection openings are geometrically separated from one another, the sealing cross section which closes the valve off from the outside being arranged downstream, as seen in the injection direction, of the variable aperture cross section, which is situated radially to the inside.

Fuel injection valve for internal combustion engines

A metering valve for metering a fluid for a fuel injection valve for internal combustion engines, with a hydraulic displacement amplifier for converting the actuating displacement of a piezoelectric actuator into an increased stroke of the valve needle. Integrating the displacement amplifier spatially into the valve housing in an 'O valve' to give a small overall volume is served by providing the lifting piston of the displacement amplifier with an end section of reduced diameter which projects into a recess in the operation piston of the displacement amplifier. A Belleville spring lying in the amplifier chamber bounded by the pistons presses the operating piston against the actuator, and a helical compression spring arranged in the recess concentrically to the end section presses the lifting piston against the valve needle.

Metering valve for metering a fluid

A fuel injection nozzle for internal combustion engines which has a valve needle loaded in the closing direction and is radially guided and supported in an axially displaceable manner within a nozzle body. The movement of the valve needle is effected in the opening and closing directions in a selectively variable manner, a spring-loaded supplementary mass which performs a dual function being disposed in the nozzle interior. In the opening direction of the valve needle, the supplementary mass is displaced along with the valve needle, while in the closing direction the two elements are separated. The supplementary mass influences the movement of the valve needle both inertially, as the result of its mass, and by effecting a speed-dependent damping, as the result of the positive displacement of a fluid from damping chambers, the whole being adapted to a constant or variable throttle disposed in the fuel inlet conduit.

A fuel injection nozzle for internal combustion engines having a valve needle which enters an intermediate position in a retarded fashion and subsequently reaches its final position quickly. The valve needle is coupled in a positively-engaged manner with a supplementary body which as a result of its mass and/or hydraulically damps the movement of the valve needle over the course of a first stroke portion. At the end of this stroke portion, the supplementary body strikes a shoulder attached to the housing, whereupon the valve needle after the attainment of a notably higher fuel pressure, is separated from the supplementary body and translated quickly into its open position. In special cases, it is also possible for two supplementary bodies to be provided, which are uncoupled one after another from the valve needle and then again recoupled to the valve upon the closure of the valve. With an apparatus of this kind, the injection procedure can be adapted more freely than in the case of the known injection nozzles to a desired course.

Fuel injection nozzle for internal combustion engines

To provide a valve stroke or displacement characteristic with respect to closing force which is at first rapidly dropping and then, after a minimum closing force is reached again increasing, so that, as the valve needle reaches its final stroke, a hard impact is avoided and rapid closure of the valve, upon drop of injection pressure, will result, a magnet circuit (88) is established in the valve housing by a magnetic element (50) and an armature (66), one of the elements being seated in the housing and the other being coupled to the valve needle (18) to provide a closure force-versus-displacement characteristics which at first drops sharply and then flattens. Further magnetic elements formed by two magnets (70, 80), with like poles facing each other are provided, to furnish the closing force-versus-displacement characteristics which increases with increasing displacement, the composite of the two forces acting on the valve being in the form of a hanging curve (FIG. 2: 98) having a minimum (F.sub.6) approximately midway along the length of the stoke of the valve needle (18).

Growing community of inventors

Leonberg, Germany

Katsuoki Itoh