Robert Boschgmbh

Martin Kropp

Hans-Christoph Magel

Bernd Mahr

Wolfgang Otterbach

Wolfgang Braun

Achim Brenk

Manfred Mack

Juergen Hammer

Christian Grimminger

Reinhard Tampe

Heike Bastian

Hans-Chris Magel

A fuel injector in injection systems for internal combustion engines having a valve body containing a control chamber that can be pressure-relieved and can be acted on with fuel via an inlet throttle and can be pressure-relieved via an outlet throttle. A first actuator can actuate a closing element. The valve body is connected to a holding body that has a nozzle body connected to it, which encompasses an injection valve element. In order to relieve the pressure in the control chamber, an additional, second outlet throttle is provided, whose closing element can be actuated either by an additional actuator or as a function of the power supply to a double-switching actuator.

Fuel injector with and without pressure ampification with a controllable needle speed and method for the controlling thereof

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.

Filter arrangement for fuel injection systems

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.

Device for damping the needle lift in fuel injectors

A fuel injection system for internal combustion engines with a fuel injector that can be supplied from a high-pressure fuel source has an injection valve, with injection nozzles pointing toward the combustion chamber, and coaxial inner and outer nozzle needles assigned to the injection nozzles are triggerable as a function of pressure to open and close various injection cross sections at the injection nozzles. Each of the nozzle needless is assigned a respective damping piston, and the damping pistons are movable relative to one another and act on a damping chamber which can be made to communicate with a low-pressure return system via an outlet throttle. In addition to the damping chamber, a closing chamber is provided, to which an end face of the outer nozzle needle is exposed in the closing direction. The closing chamber can be made to communicate with the low-pressure return system as well, via a closing chamber throttle; the outlet throttle has a greater throttling action than the closing chamber throttle, so that the pressure in the closing chamber drops first, and only after a delay does the pressure in the damping chamber drop as well.

Fuel injection system for internal combustion engines with needle stroke damping

A fuel injection system includes a pressure chamber having a displacable piston which can be subjected to pressure via a low-pressure-side pressure booster chamber for compressing the fuel in a high-pressure-side pressure booster chamber to be delivered to an injector. The stroke of the piston is controllable essentially by the pressure in a differential chamber of the pressure chamber and is used to vary the fuel pressure delivered to the injector. Provision is made for enlarging the cross section of the outlet cross section out of the differential chamber of the pressure chamber are provided. The fuel pressure during the injection can be varied. A pressure increase can be simply achieved.

Fuel injection device with a pressure booster

A fuel injection system includes a pressure booster having a displaceable piston which can be subjected to pressure via a pressure booster chamber on the low-pressure side for compressing the fuel in a pressure booster chamber on the high-pressure side to be delivered to an injector. The stroke of the piston is controllable by the pressure in a differential chamber of the pressure booster and is used to vary the fuel pressure delivered to the injector. Means for continuously variable definition of the inlet cross section to the pressure booster chamber of the pressure booster on the low-pressure side or of the outlet cross section from the differential chamber of the pressure booster are provided.

Fuel injection device comprising a pressure amplifier

A pressure booster of a fuel injection system includes a displaceable piston unit (), which on one end can be subjected to pressure via a pressure booster chamber on the low-pressure side and on the other end has a pressure booster chamber on the high-pressure side for fuel compression. The piston unit has a further piston cross section, which is reduced compared to the first piston cross section provided for imposing pressure, for embodying a differential chamber that is connectable to a leak fuel line. At least one control conduit connects the pressure booster chamber on the low-pressure side to the differential chamber, whose opening is closed or opened as a function of the motion of at least parts of the piston unit.

Pressure booster for a fuel injection system

A fuel injection system for internal combustion engines has at least one stroke-controlled injector. A pressure booster that has a movable piston is connected between the at least one injector and a high-pressure working medium source. The movable piston divides a primary chamber, which can be connected to the high-pressure working medium source, from a pressure chamber that communicates with the at least one injector and is filled with fuel. The pressure booster generates a first fuel system pressure in the injector, which is used for the injection. The fuel injection system has means for furnishing a further, second fuel system pressure, and these means can be used for injection without activating the pressure booster.

Fuel injection device

A fuel injection apparatus includes a shared pressure reservoir, an injector, a pressure intensifier, and valves for controlling the injection process and the pressure intensification. A modular design is produced by means of a pressure intensifier module, and a valve module, thereby reducing costs and increases flexibility in the manufacture of fuel injection apparatuses.

An injection nozzle of a stroke-controlled fuel injection device has a control chamber for triggering a nozzle needle and also has a nozzle chamber connectable to a pressure booster. The communication between a differential chamber of the pressure booster and a leakage line and the communication between a control chamber and a leakage line are controllable with the aid of a common valve.

A fuel injection system has one or more unit fuel injectors or pump-line-nozzle units, corresponding in number to the cylinders, for compressing the fuel. The fuel injection system includes means for generating two different injection pressures during the injection and at least one valve for controlling the injection with a cross sectional control. The fuel injection with the aid of the unit fuel injector or a pump-line-nozzle unit can be achieved over a wide rpm range with great precision.

A method for injecting fuel at at least two different high fuel pressures via injectors into the combustion chamber of an internal combustion engine. The fuel injection at the higher fuel pressure takes place by pressure-controlled features, during the fuel injection, at least one lower fuel pressure is generated. To that end, a fuel injection system has one local diversion unit for each injector, and the diversion unit can be activated or deactivated via a valve unit.

Fuel injection method and systems for an internal combustion engine

In a fuel injection system for an internal combustion engine, in which fuel at at least two differently high fuel pressures can be injected via injectors into the combustion chamber of the engine, parallel to a bypass line a hydraulic pressure booster is provided for generating the higher fuel pressure; the pressure booster is actuatable and deactuatable via a valve unit. Since the pressure booster is not constantly in operation, and the losses from friction are also reduced, the efficiency is improved.

Fuel injection system for an internal combustion engine

A fuel injection is effected by means of a high-pressure pump ( ) and a pressure reservoir chamber ( ) for generating and storing a first system pressure. This system pressure is not used for injection; instead, by means of the pressure booster unit ( ), a higher injection pressure is generated during the injection, and this injection pressure can be reduced to shape the course of injection. By means of this invention, an improved capability of metering the fuel injection and an improved execution of fast switching times are achieved.

Method and apparatus for performing a fuel injection

In a pressure-controlled fuel injection system, a nozzle needle is subjected to pressure in the closing direction by a nozzle spring. A nozzle chamber for opening the nozzle needle is connectable to a pressure reservoir via a pressure line. A hydraulic device is embodied to reinforce the closing performance of the nozzle needle. As a result, a faster closing performance of the nozzle needle is achieved.

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Tamm, Germany

Martin Kropp