Internal-combustion engines – Charge forming device – Fuel injection system
Patent
1986-07-10
1988-10-25
Miller, Carl Stuart
Internal-combustion engines
Charge forming device
Fuel injection system
123467, 123500, 123496, F02M 3900
Patent
active
047795964
DESCRIPTION:
BRIEF SUMMARY
STATE OF THE ART
The invention relates to a device for injecting fuel in internal combustion engines. In known devices of this type the locking force of the locking spring element can be changed by an axial displacement of its housing mounted support shoulder, however relatively expensive means are required. In furtherance, devices of the type are known (DE-A1-33 44 396.3) wherein the injection for forming a clearly defined preinjection phase is shortly interrupted in a defined range of the operating performance graph. In these devices it is relatively difficult to adjust with respect to each other the parameters with respect to each other which influence the operation of the injection. Furthermore, the state of the art also recognizes injection jets (DE-OS 15 76 570) which have a stretched tension wire as a locking spring element. With this design of the locking spring element a high inherited frequency of the oscillating system may be obtained consisting of the valve locking member and the locking spring element, however the locking force of the tension wire can only be adjusted, but cannot be changed during the operation of the engine.
ADVANTAGES OF THE INVENTION
In contrast thereto the inventive arrangement with the characterizing features of the main claim is advantageous in that with simple or accurately controllable means the opening pressure of the injection jet or the injection process during the operation can be changed. Moreover, there is also a high spring stiffness of the locking spring element.
In keeping with these objects and others, one feature of the invention resides in a device for injecting fuel into combustion chambers of internal combustion engines, comprising an injecting element including a valve body provided with a valve seat, a valve member displaceable in the valve body so that to open the valve seat in a flow direction of a fuel, and a closing element acting upon the valve body opposite to a fuel pressure; and means for changing a closing force of the closing element and thereby changing a fuel opening pressure during running of an internal combustion engine, the closing element being formed as a tension wire, and changing means including an electrical current circuit and a resistor arranged so as that electrical current circuit supplies a current flow via the electrical resistor element to the tension wire so as to change its pretensioning and therefore to change the closing force of the closing element.
One embodiment which does not require any additional mechanical means is obtained if the electric resistance element is formed by the tension wire itself, so that the current throughput through the tension wire is changeable in measurably influencing manner of its locking force or is controllable in accordance with a predetermined mathematical interrelationship.
The opening pressure of the injection jet can be controlled when the injection jet is provided with a sensor which picks up the opening pressure and, if need be, with a sensor which picks up the lifting off of the valve locking member from the valve seat. This second sensor may be a switch formed by the valve locking member and the valve seat and which advantageously may also be used as an injection starter transmitter or a constant injection transmitter for an evaluation circuit.
The injection process itself may be influenced or shaped by means of a temporary intervention in accordance with a defined mathematical principle if the electric resistance element which changes the pretension of the tension wire is the coil of a magnet, whose anchor is coupled with the tension wire and acts on the tension wire in the locking direction during its initial pulling movement.
DRAWING
Two exemplified embodiments are illustrated in the drawing and explained in more detail in the following description.
FIG. 1 illustrates the injection jet of the first exemplified embodiment in a longitudinal section with the power circuits for the electrical functions of the device,
FIG. 2 illustrates a partial longitudinal section through t
REFERENCES:
patent: 4275693 (1981-06-01), Leckie
patent: 4359032 (1982-11-01), Ohie
patent: 4438496 (1984-03-01), Ohie
patent: 4640252 (1987-02-01), Nakamura
patent: 4669429 (1987-06-01), Nishida
Babitzka Rudolf
Linder Ernst
Polach Wilhelm
Miller Carl Stuart
Robert & Bosch GmbH
Striker Michael J.
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