Fluid sprinkling – spraying – and diffusing – Fluid pressure responsive discharge modifier* or flow... – Fuel injector or burner
Utility Patent
1999-12-17
2001-01-02
Kashnikow, Andres (Department: 3752)
Fluid sprinkling, spraying, and diffusing
Fluid pressure responsive discharge modifier* or flow...
Fuel injector or burner
C239S124000, C239S533400
Utility Patent
active
06168096
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention is based on a fuel injection device for internal combustion engines. In one such fuel injection device, known from German Patent Disclosure DE 196 24 001 A1, the valve chamber in a first version communicates with the control chamber without any reduction in cross section. Upon actuation by the piezoelectric actuator, the control valve makes the outflow cross section to the outflow conduit either fully open or the central valve closes the outflow cross section. In another version, the valve chamber communicates with the control chamber via a connecting conduit, and the connecting conduit is coaxial with the valve seat on the side of the outflow conduit. By actuation of the control valve member by the piezoelectric actuator, either the outflow cross section from the valve chamber to the outflow conduit is fully opened or closed, or to attain a preinjection, the control valve member is moved away from the valve seat toward the outflow conduit to the entrance of the connecting conduit and to the valve chamber; as a consequence of this motion, the control chamber is briefly opened to the outflow conduit via the valve chamber. For an ensuing main injection, the control valve member is moved into a middle position, in which both the cross section toward the outflow conduit and the cross section of the connecting conduit into the valve chamber are fully opened. This embodiment has the disadvantage that to relieve the pressure in the control chamber, only a single, geometrically defined outflow cross section to the outflow conduit exists. The preinjection quantity in the second version described is such that the speed of adjustment of the control valve member by the piezoelectric actuator and the geometrically defined travel of the control valve member are predetermined variables for the degree of relief of the pressure in the control chamber. In particular, the maximum relief cross section is the same for both the relief for the preinjection and for the relief for the main injection, which is disadvantageous in view of any fine adaptation of the opening speed of the injection valve in various operating conditions.
OBJECT AND SUMMARY OF THE INVENTION
The fuel injection device according to the invention has an advantage that two different outflow cross sections can be established in succession, by making two different connection cross sections to the control chamber as a function of the position of the control valve member. It is thus possible to graduate the outflow cross section as a function of the stroke. Particularly for a slight relief of the control pressure in the control chamber, a first, smaller outflow cross section can come into effect, with which the preinjection stroke of the injection valve member can be set with greater precision. For the main injection, a large outflow cross section is subsequently available, which allows a fast motion of the injection valve member.
Advantageously, a cross section that is additional to the first connection cross section is provided as the second connection cross section. This makes it possible to attain a large effective change in cross section. The first connection cross section is located in a space-saving way in the intermediate valve member, where sufficiently large flow cross section is furnished on the outer circumference. The second connection cross section can be defined by the flow cross section at the interstices between the longitudinal ribs, which is determined by the stroke of the intermediate valve member, which uncovers a certain flow cross section between the sealing seat shoulder and the sealing face.
In a further feature crosswise connections that are always open are furnished between the connecting conduit of the valve member and the valve chamber, so that this connecting conduit is ready as an always-open first connection cross section, to which a further, second connection cross section is added when the intermediate valve member is opened.
It is also advantageous to close the connecting conduit in the intermediate valve member when the control valve member contacts the intermediate valve member; thus the cross section of the connecting conduit is furnished not in the intermediate valve member, but along the outer circumference of the intermediate valve member.
The invention will be better understood and further objects and advantages thereof will become more apparent from the ensuing detailed description of preferred embodiments taken in conjunction with the drawing.
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patent: 5429154 (1995-07-01), Kato
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patent: 5860597 (1999-01-01), Tarr
patent: 5904300 (1999-05-01), Augustin
patent: 6027047 (2000-02-01), Augustin
patent: 6092737 (2000-07-01), Bosch et al.
Boecking Friedrich
Potschin Roger
Greigg Edwin E.
Greigg Ronald E.
Kashnikow Andres
Kim Christopher S.
Robert & Bosch GmbH
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