Robert Boschgmbh

Peter Stiefel

Klaus-Jurgen Peters

Karl Gmelin

Hermann Nusser

Michael Wissmann

Max Greiner

Heinz Ehrentraut

Klaus J Peters

Wolfgang Maisch

Peter Schelhas

Peter Schelthas

Jurgen Peters

A differential pressure valve is proposed for a fuel injection system of an internal combustion engine. The differential pressure valve includes a diaphragm embodied as the movable valve element, which separates two chambers from one another. A fuel supply line discharges into one chamber and a valve seat carrier provided with a valve opening protrudes into this chamber. This chamber also houses a filter element and a valve spring is disposed coaxially with the valve seat carrier between upper and lower spring plates. The filter element is disposed such that a subsequent change in the tension of the valve spring is also possible. To this end, the filter element can engage the upper spring plate on one side in a sealing manner and on the other side can be supported in a sealing manner in a groove of the wall of the chamber (FIG. 1). In order to assure the free mobility of the filter element, it is provided with an elastically deformable area. As shown in FIG. 2, the filter element may, however, also engage the lower spring plate in a sealing manner and with its other end surroundingly engage the spring plate with as little play as possible, to thereby form a labyrinth seal.

Differential pressure valve for a fuel injection system

A fuel injection system is proposed which serves to provide the most precise possible adaptation of the fuel-air mixture to operating conditions of the internal combustion engine. The fuel injection system includes metering valves, each of which is assigned one regulating valve, whose movable valve element can be exposed on the one hand to the fuel pressure downstream of the respective metering valve and on the other hand to the pressure in a control pressure line, which is limited on the one hand by an electro-fluid converter of the nozzle/bounce plate type and on the other hand by a control throttle. The electro-fluid converter is triggerable in accordance with operating characteristics of the engine. A pressure limitation valve is embodied as a diaphragm valve and serves to regulate the most precise possible system pressure in the engine and, when the engine is shut off, it serves to reduce the fuel pressure in the fuel injection system below the fuel pressure required for opening the injection valves and to block the return flow lines.

Fuel injection system

A fuel injection system is proposed which serves to supply fuel to a mixture-compressing, externally ignited internal combustion engine. The fuel injection system includes an air flow rate member, which actuates a metering and distribution valve. A reservoir is disposed in a pressure control line which branches off from a fuel supply line, by means of which reservoir a flushing valve can be affected in such a manner that below a certain fuel pressure in the pressure control line the flushing valve is opened, as a result of which the fuel supplied to the individual injection valves can flow back through outflow lines to the fuel tank and thus closes the flushing valve above the certain fuel pressure. Above the certain fuel pressure, the electrical circuit of the starter motor is simultaneously closed. Thus, upon starting the engine, all the lines and units of the fuel injection system are filled with fuel, so that a secure start is assured.

A metering and distribution valve assembly is proposed for a fuel injection system of an internal combustion engine. The metering and distribution valve assembly includes a control slide having a head 68 and a control edge and a slotted sleeve with at least two control slits. The control edge opens the control slits to a greater or lesser degree in accordance with the relative motion between the control slide and the control slits in the slotted sleeve. An end face of the control slide adjacent to the control edge is exposed to a control pressure which is lower than the system pressure engaging the control edge. The pressure drop at the circumference of the control slide head formed between the control edge and the end face is capable of being influenced in such a manner that the control slide head rests unilaterally on the slotted sleeve at least during a portion of the displacement movement. As a result, better metering precision is obtained. The unilateral resting of the control slide head on one side of the slide bore can be effected either by the application of fuel at system pressure at the aperture or by the application of fuel at control pressure at the longitudinal groove.

Metering and distribution valve assembly

A fuel injection system which serves to supply fuel to a mixture-compressing, externally ignited internal combustion engine which includes an air flow rate member for actuating a metering and distribution valve, a flushing valve is disposed in an outlet line leading from each injection valve to a return flow line open when the engine is turned off and immediately after actuation of the ignition switch of the engine, enables a return flow via the outlet lines of the fuel flowing through the fuel supply line and the metering and distribution valve assembly to the injection valves until an electromagnetic valve drivable by a time control element opens a pressure line to a pressure chamber of the flushing valve, and the pressure prevailing in the pressure chamber opens a diaphragm connected to the movable valve parts of the flushing valve in such a manner that the flushing valve closes. Simultaneously with the opening of the electromagnetic valve, the electrical circuit of the starter motor is closed, so that after the preceding filling with fuel of all the lines and assemblies of the fuel injection system with fuel, a more certain start of the engine is assured.

A fuel supply device is proposed which serves to supply fuel to a mixture-compressing, externally ignited internal combustion engine with a good distribution of the fuel-air mixture. The fuel supply device includes a fuel metering device activated by an air metering device arranged in the air intake manifold of the internal combustion engine with the fuel metering device being connected to an air line in which the metered fuel is mixed with air before the injection into the air intake manifold. Between the air line and the fuel line, upstream from the fuel metering position, a filter having a fine-meshed weave is arranged by means of which the fuel is prevented from flowing out over the air line in an undesirable manner.

Fuel supply device

A fuel supply device, which serves to predetermine a fuel quantity that is proportional to the aspirated air quantity, and also serves to spread the air-fuel mixture. The fuel supply device includes an air metering device, which is arranged in the air intake manifold of the internal combustion engine and activates a fuel metering device, which has a control slit that opens a control groove by a varying amount. The control slit and the control groove are rotatable relative to each other, and the control groove has at least one control edge, which overlaps the control slit and is formed at an angle relative to the axis of rotation. The control slit is arranged in a guide sleeve and the control groove is arranged in a rotatable sleeve mounted in the guide sleeve with the rotatable sleeve being arbitrarily shifted relative to the guide sleeve. A connecting tube is arranged between the rotatable sleeve and the mounting axis of the air metering device, by means of which the metered fuel can be fed to a nozzle arranged on the air flow rate meter. For a better mixture spreading effect, air can be fed to the metered fuel through a filter composed of a fine-meshed web.

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Ditzingen, Germany

Peter Stiefel