Internal-combustion engines – Combustion chamber means having fuel injection only – Using multiple injectors or injections
Reexamination Certificate
2000-04-10
2001-06-12
Miller, Carl S. (Department: 3747)
Internal-combustion engines
Combustion chamber means having fuel injection only
Using multiple injectors or injections
C123S467000
Reexamination Certificate
active
06244245
ABSTRACT:
PRIOR ART
The invention is based on a valve control unit for a fuel injection valve for a common rail injector.
A valve control unit of this type is known, for example, from EP 0 661 442 A1.
Valve control units of this type are provided for controlling the injection process in the preinjection and main injection of fuel (diesel fuel) in common rail injectors. The valve control unit influences the impingement of pressure on the one end of a movably supported valve control piston of the valve control unit. The other end of the valve control piston can act on an injector needle so that the injector needle either closes an injection opening or permits fuel to escape from the injection opening.
With the known valve control unit, the impingement of pressure on the valve control piston is carried out by changing the pressure conditions inside a first valve control chamber, which communicates with a high pressure reservoir (common rail) by way of a supply conduit. When the valve control unit is triggered, an outlet conduit is opened, which is connected to a second valve control chamber that continuously communicates with the first valve control chamber. As a result, the pressure in the first valve control chamber decreases and the hydraulic force on the valve control piston decreases. Disadvantageously, a large-volume end member connected to the valve control piston must be moved inside the first valve control chamber. Due to the stroke motion of the valve member, during the preinjection, the injected quantity of fuel cannot be sufficiently minimized. During the main injection, it is likewise disadvantageous that a large volume of fuel inside the first valve control chamber must be displaced by the end member when the valve control piston moves away from the injection opening. This prevents an increased movement speed of the valve control piston and therefore also of the injector needle during the main injection.
ADVANTAGES OF THE INVENTION
The valve control unit according to the invention, for a fuel injection valve for a common rail injector operates to minimize the quantity of preinjected fuel and to increase the movement speed of the valve control piston.
Whereas the end member in the prior art is comprised of one part, this invention is comprised of two parts: an inner structural member and an outer structural member. The two structural members can be moved in relation to each other and are connected to the valve control piston. When the outlet conduit is opened and fuel escapes from the first valve control chamber into the second valve control chamber, the two structural members of the end member can move inside the first valve control chamber. During the preinjection, the two structural members move together by a small stroke, whereas during the main injection, only the inner structural member moves by an additional stroke. This results in the fact that during the preinjection, due to the movement of the valve control piston, a greater volume of fuel must first be displaced from the first valve control chamber by the end member (inner and outer structural member). Therefore, the valve control piston can only execute a small stroke. The preinjected quantity of fuel is therefore kept low. In contrast, during the main injection, only the inner structural member of the end member moves so that a smaller volume of fuel has to be displaced from the first valve control chamber. The valve control piston can therefore be moved with an increased movement speed and a larger stroke.
In a preferred embodiment, the first valve control chamber has a first stop to limit the movement of the outer structural member in the direction of the second valve control chamber and has a second stop to limit the movement of the inner structural member in the direction of the second valve control chamber. Through the embodiment of the two stops, the movement of the structural members inside the first valve control chamber is executed in a definite and reproducible manner. A uniform small quantity of fuel is always preinjected, without impairing the increased movement speed during the main injection.
Other advantages and advantageous embodiments of the subject of the invention can be inferred from the specification, the drawing, and the claims.
REFERENCES:
patent: 4022165 (1977-05-01), Eckert et al.
patent: 4640252 (1987-02-01), Nakamura et al.
patent: 5575253 (1996-11-01), Lambert et al.
patent: 5862793 (1999-01-01), Jay et al.
patent: 5901685 (1999-05-01), Noyce et al.
patent: 6012430 (2000-01-01), Cooke
patent: 6085719 (2000-07-01), Heinz et al.
patent: 661442 (1995-07-01), None
patent: 686763 (1995-12-01), None
Greigg Edwin E.
Greigg Ronald E.
Miller Carl S.
Robert & Bosch GmbH
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