Fluid sprinkling – spraying – and diffusing – Unitary injection nozzle and pump or accumulator plunger – Plunger interconnected or mounted valve
Reexamination Certificate
1999-09-29
2001-01-30
Kashnikow, Andres (Department: 3752)
Fluid sprinkling, spraying, and diffusing
Unitary injection nozzle and pump or accumulator plunger
Plunger interconnected or mounted valve
C239S124000, C239S585100
Reexamination Certificate
active
06179220
ABSTRACT:
TECHNICAL FIELD
The invention relates to a fuel injection apparatus, in particular for diesel engines, comprising at least one injection nozzle which is connected up to a fuel pressure line and which has a nozzle element which can be actuated through a control unit for the opening and the closing of the injection nozzle.
BACKGROUND OF THE INVENTION
Injection apparatuses of this kind are known in principle and serve for the supplying at the proper time point of a specific amount of fuel, which is injected under high pressure directly into the cylinder in a diesel engine, to the combustion chamber of a cylinder which is associated with the injection nozzle.
The objective of this invention is to provide as simply constructed a fuel injection apparatus of the initially named kind as possible which enables an ideal actuation of the nozzle element and which can be adapted in the simplest possible way to different requirements.
SUMMARY OF THE INVENTION
This object is satisfied in accordance with the invention by the features of claim
1
and in particular in that the control unit comprises a piston which is displaceably journalled in a control passage, which is coupled at its one end to the nozzle element and which bounds with its other end together with a plug which is arranged in the control passage a pressure chamber which can be connected to the fuel pressure line via a supply passage and which communicates with an outflow passage; in that the pressure in the pressure chamber can be varied through the release or the interruption of the outflow passage for the actuation of the nozzle element when the pressure chamber is connected via the supply passage to the fuel pressure line; and in that the flow through the supply passage into the pressure chamber and the flow out of the pressure chamber into the outflow passage can be influenced through a displacement of the piston as a result of a pressure change in the pressure chamber.
In accordance with the invention the force acting on the piston and thus on the nozzle element which is coupled to the piston can be varied through a variation of the pressure in the pressure chamber in such a manner that it is either greater or less than the force which acts on the piston via the nozzle element of the injection nozzle which is connected up to the fuel pressure line. In dependence on the magnitude of the pressure in the pressure chamber the injection nozzle is thus opened or closed.
The temporal behaviour of the pressure variation in the pressure chamber is dependent on the flow relationships in the flow path from the fuel pressure line into the pressure chamber, from the outlet opening of the supply passage through the pressure chamber to the inlet opening of the outflow passage and through the outflow passage. Through a variation of the geometrical relationships in the pressure chamber, in particular the size of the inlet opening, the size of the outlet opening and/or of the axial distance between the inlet opening and the outlet opening, the fuel injection apparatus in accordance with the invention can be adapted to different requirements in a simple way.
In the fuel injection apparatus in accordance with the invention both the supply passage and the outflow passage are in connection with the pressure chamber. This enables the geometry of the pressure chamber to be designed in such a manner that when the injection nozzle opens, the piston which moves in the direction of the plug simultaneously reduces the flow cross-sections in the region of the outlet opening of the supply passage and the inlet opening of the outflow passage. In this way the intake and the outlet of the pressure chamber can be throttled at the same time. This functional principle is designated as the STOP principle (Simultaneously Throttled Orifice Principle).
The fuel injection apparatus in accordance with the invention can be used in conjunction with multiple cylinder engines in such a manner that a control unit which is designed in accordance with the invention is associated with each injection nozzle and the injection nozzles are connected up to a common fuel pressure line. An arrangement of this kind is also designated as a “common rail injector” or a “common rail injection”.
In accordance with a preferred exemplary embodiment of the invention the supply passage and the outflow passage are in each case formed at least region-wise in the plug.
Through this it is enabled to provide a simply constructed piston and to determine the geometry of the pressure chamber substantially through the shape of the plug. Thus, for the adaptation of the injection apparatus to different requirements, the plug need merely be replaced in order to enable the respective desired type and manner of the variation of the pressure.
In accordance with a further preferred embodiment of the invention the injection nozzle is connected via a supply line to the fuel pressure line and is connected up to an outflow line, with the supply passage being connected at the supply line and the outflow passage at the outflow line, and with the supply line, the outflow line and the control passage being formed in a connector piece.
Through this a particularly simple construction of the injection apparatus in accordance with the invention results.
In accordance with a further preferred exemplary embodiment of the invention it is provided that the supply passage and the outflow passage in each case open into the pressure chamber at an end side of the plug facing the piston at regions which have a different axial distance from an end side of the piston facing the plug.
The difference in the axial distance of the openings of the supply passage and of the outflow passage, i.e. of an outlet opening of the supply passage and of an inlet opening of the outflow passage, from the end side of the piston has as a result that, when the outflow passage is released for the opening of the injection nozzle and when the piston moves in the direction towards the plug, the throttling of the fuel flows through the outlet opening and the inlet opening begin at different time points. The flows through the outlet opening and through the inlet opening can be throttled at the same time in this manner, with however the extent of the throttling being of different magnitudes at the same times.
The ratio of the extent of the two throttlings with respect to one another is in this dependent on the size of the distance between the outlet opening and the inlet opening. At a large distance the flow through the opening which lies closer to the end side of the piston facing the plug is more strongly throttled than the flow through the other opening. In contrast, in the case of a small distance the throttlings of the two flows take place in substantially the same manner.
The temporal behaviour of the pressure variation in the pressure chamber is determined by the ratio of the amount of fuel flowing per unit time through the two openings, i.e. out of the supply passage into the pressure chamber and via the outflow passage out of the pressure chamber, and can thus be determined in the desired manner through the corresponding choice of the difference between the axial distances of the inlet opening and the outlet opening from the end side of the piston.
In accordance with a further embodiment of the invention it is provided that the supply passage and the outflow passage open into the pressure chamber in each case at an end side of the plug facing the piston at regions which are spaced with respect to one another in the axial direction, with a planar end side of the piston facing the plug preferably extending substantially perpendicular to a longitudinal axis of the piston, which preferably coincides with the longitudinal axis of the control unit.
Through this the throttling ratio is determined by the axial distance between the outlet opening of the supply passage and the inlet opening of the outflow passage. Thus for the adaptation of the injection apparatus in accordance with the invention to different requirements, a plug having the respective su
Breitbach Hermann
Kolkman Manfred
Delphi Technologies Inc.
Kashnikow Andres
Nguyen Dinh Q.
VanOphem John A.
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