Internal-combustion engines – Charge forming device – Fuel injection system
Reexamination Certificate
2000-04-12
2001-06-19
Moulis, Thomas N. (Department: 3747)
Internal-combustion engines
Charge forming device
Fuel injection system
C239S453000
Reexamination Certificate
active
06247453
ABSTRACT:
DESCRIPTION AND PRIOR ART
The invention relates to a fuel injection valve for internal combustion engines.
Such an injection valve is disclosed for instance in German Patent DE 43 25 904 C2, as well as German Patent Application DE 197 16 226.6-13, which had not been published by the priority date of the present application.
One problem in such fuel injection valves is guiding and sealing the valve member in the valve body
1
. Thus particularly if the bores are not oriented exactly, or if the valve member has slight kinks, guidance and sealing problems occur.
ADVANTAGES OF THE INVENTION
The fuel injection valve according to the invention has the advantage over the prior art that the guidance and sealing is improved over the fuel injection valves for internal combustion engines known from the prior art. Disposing one pressure shoulder on the end remote from the combustion chamber of the valve body in a compensation chamber communicating fluidically with the pressure chamber and closed off on its face end by an axially displaceably guided pressure sleeve has the particularly great advantage that the compensation chamber always communicates with the pressure chamber. This assures that the pressure shoulder will always be acted upon by a pressure; it is assured that pressure differences, for instance when the fuel injection valve opens, between the pressure chamber and the compensation chamber are compensated for directly. In this way, a restoration to the closing position of the fuel injection valve is always provided—even if a force acting in the opening direction is exerted on the valve member, for instance because of a leak toward the combustion chamber, caused by a resultant pressure difference between the pressure shoulders. The valve member is advantageously formed in needle-like fashion between the two pressure shoulders and has a constant diameter. Because the valve member is embodied as a thin needle of constant diameter between the two pressure shoulders, a slight offset between the guides, formed hand by the valve member head other by the pressure sleeve, can be compensated for in a simple and advantageous way.
To avoid leaks, the pressure sleeve is preferably press-fitted onto the valve member. Purely in principle, the compensation chamber can be embodied in an arbitrary way. One embodiment that is advantageous in particular with respect to ease of manufacture provides that the compensation chamber annularly surrounds the pressure shoulder remote from the combustion chamber.
The high-pressure delivery of fuel to the fuel injection valve is preferably done from a high-pressure reservoir common to all the fuel injection valves, and the high-pressure reservoir can in turn be filled via a high-pressure fuel pump.
The actuator for actuating the valve member is advantageously an electromechanical actuator. In particular, it is embodied as a piezoelectric actuator or electromagnet.
Further advantages and advantageous features of the subject of the invention can be learned from the description, drawing and claims.
REFERENCES:
patent: 4825828 (1989-05-01), Schlunke et al.
patent: 5024385 (1991-06-01), Olson
patent: 5090625 (1992-02-01), Davis
patent: 43 25 904 (1995-02-01), None
patent: 96/25596 (1995-02-01), None
Boecking Friedrich
Potschin Roger
Greigg Edwin E.
Greigg Ronald E.
Moulis Thomas N.
Robert & Bosch GmbH
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