Abstract: In a fuel injection system for an internal combustion engine, in which fuel can be injected at least two different, high fuel pressures, via injectors, into the combustion chamber of the engine, having a central first pressure reservoir for the higher fuel pressure and a central second pressure reservoir, supplied from the first pressure reservoir, in which by regulation of its fuel delivery, the lower fuel pressure is maintained, and having a valve unit for switchover between the higher and the lower fuel, the valve unit for switchover between the higher and the lower fuel is provided locally for each injector. With this injection system, improved metering of the lower fuel pressure is possible.

Abstract: In a fuel injection system for an internal combustion engine, in which fuel can be injected at at least two differently high fuel pressures via injectors into the combustion chamber of the engine, having a central distributor device for distributing the fuel to the individual injectors and having a central pressure reservoir for the lower fuel pressure, one valve unit for switchover between the two fuel pressures is provided locally for each injector individually. Furthermore, the central distributor device for the higher fuel pressure is disposed parallel to the central pressure reservoir for the lower fuel pressure. To enlarge the injection window for the pre-injection and the post-injection, the lower fuel pressure is metered from the central pressure reservoir, without going by way of the distributor device.

Abstract: A fuel injection system has one or more unit fuel injectors or pump-line-nozzle system, corresponding in number to the number of cylinders, for compressing the fuel and a hydraulic pressure booster unit. With the aid of the unit fuel injector and the pressure booster unit, a fuel injection can be performed with great precision over a wide rpm range.

Abstract: A fuel injection system having at least two different, high system pressures for an internal combustion engine, includes a first central pressure reservoir for the lower system pressure and includes a second central pressure reservoir, supplied from a high-pressure pump, for the higher system pressure, both pressure reservoirs being connectable by line to the injector of each cylinder, and to increase the efficiency, a two-stage high-pressure pump, by whose lower stage the first pressure reservoir and by whose higher stage the second pressure reservoir are supplied.

Abstract: In a method for injecting fuel at at least two differently high fuel pressures via injectors into the combustion chamber of an internal combustion engine, the fuel injection at the lower fuel pressure takes place under stroke control, and the fuel injection at the higher fuel pressure takes place under pressure control. For a pre- and/or post-injection and/or a boot injection at the lower fuel pressure, the control chamber and via a check valve the nozzle chamber as well are connected to a low-pressure fuel supply, and that for a main injection at the higher fuel pressure, the nozzle chamber is connected to the high-pressure fuel supply.

Abstract: A fuel injection system has a pressure step-up unit, disposed between a pressure storage chamber and a nozzle chamber, whose pressure chamber communicates with the nozzle chamber via a pressure line. A bypass line connected to the pressure storage chamber is also provided. The bypass line communicates directly with the pressure line. The bypass line can be used for pressure injection and is disposed parallel to the pressure chamber, so that the bypass line is open regardless of the motion and position of a displaceable piston element in the pressure step-up unit. This enhances the flexibility of injection.

Abstract: In a fuel injection system for an internal combustion engine, having at least two different, high system pressures, in which a first pressure reservoir supplied by a first pump is provided for the lower system pressure and a second pressure reservoir supplied by a second pump is provided for the higher system pressure, and in which at least the second pressure reservoir or a fuel injection can be made to communicate by line with the injectors of the individual cylinders of the engine. The second pump communicates on its inlet side with the first pressure reservoir.

Abstract: An injection nozzle of a pressure-controlled fuel injection system has a control chamber for exerting pressure on a nozzle needle. The control chamber is connectable to a pressure reservoir via a pressure line that includes a 2/2-way valve. On the end of the nozzle needle that can be acted upon by pressure and is remote from the injection opening, a bore is embodied, by way of which the control chamber of the injection nozzle can be made to communicate with a leakage line as a function of the stroke of nozzle needle.

Abstract: A device for introducing a reducing agent, such as a solution of water and urea, into an exhaust pipe segment of an internal combustion engine that leads to a reduction catalytic converter. The reducing agent is introduced into the exhaust pipe via a reducing agent line discharging into the exhaust pipe, and the orifice end of the reducing agent line is provided with a spray head, which has at least one spray opening and a tapering cross section.

Abstract: In order to determine the course of a varying internal pressure in the cylinder of a piston-type internal combustion engine using measurement sensors which are in interaction with the outside of the cylinder; an acceleration, velocity or displacement signal (X(t)) is produced and a transfer function (H(.omega.)) between the internal pressure (Y(t)) and the acceleration, velocity or displacement signal (X(t)) is determined once and thereafter an output signal representing the internal pressure is derived only from the acceleration, velocity or displacement signal X(t)) and the transfer function.