Fluid sprinkling – spraying – and diffusing – Including valve means in flow line – And filter – sifter or screen
Reexamination Certificate
2000-05-15
2001-02-13
Miller, Carl S. (Department: 3747)
Fluid sprinkling, spraying, and diffusing
Including valve means in flow line
And filter, sifter or screen
C239S590500, C123S510000
Reexamination Certificate
active
06186420
ABSTRACT:
PRIOR ART
The invention is based on a fuel injection valve for internal combustion engines. One such fuel injection valve, known from German Patent Disclosure DE 196 08 608, has a fuel inlet conduit leading away from a connection stub for a fuel injection line, which conduit discharges at an injection opening into the combustion chamber of the engine to be supplied. For trapping dirt particles and chips in the fuel, a rodlike fuel filter is inserted into the inlet conduit and is guided via collar faces, provided on its axial face ends, in a bore of the fuel inlet conduit. The rotationally symmetrical filter body of the fuel filter has a middle portion of reduced diameter between its two collar faces. Two groups of longitudinal grooves axially closed on one end are machined into this middle portion, of which a first group originates at an upper end face of the filter body remote from the injection opening, and a second group originates at a lower end face thereof, oriented toward the injection opening. The longitudinal grooves of the first and second groups are distributed in alternation over the circumference of the filter body. When there is a flow of fuel through the fuel inlet conduit, the fuel is forced at the filter body to pass through the narrow gap between the profiled outer circumference of the filter body in the center portion and the wall surrounding the filter body of the inlet conduit, so that dirt particles, chips and so forth entrained with the fuel are restrained, beyond a certain size, when the fuel flows from the longitudinal grooves of one group over into the longitudinal grooves of the other group. The restrained particles then accumulate at the closed lower end of reduced cross section of the longitudinal grooves originating at the upper end face, remote from the injection opening.
The known fuel injection valve has the disadvantage that a relatively large idle volume exists at the fuel filter. Furthermore, the pressure losses, because of the poor adaptation between the flow cross sections of the fuel filter and the inlet line and the flow cross sections at the injection openings, are too great to allow effective conversion of the high fuel pressure, built up by the high-pressure fuel pump, at the injection openings of the injection valve. The known fuel injection valves, for use in direct-injection internal combustion engines, thus no longer meet the high injection pressures demanded.
ADVANTAGES OF THE INVENTION
The fuel injection valve according to the invention for internal combustion engines, has the advantage over the prior art that by the adaptation of the flow cross sections of the fuel filter and the inlet conduit to the total injection cross section of the injection valve, the pressure losses within the fuel inlet conduit and in particular at the fuel filter can be greatly reduced. By embodying the fuel injection valve according to the invention, the idle volume in the fuel inlet conduit and at the fuel filter can furthermore be reduced, which has a still more favorable effect on the injection event. These improvements are attained by the layout according to the invention of the size of the flow cross section of the fuel filter and of the flow cross section of the fuel inlet conduit downstream of the fuel filter, which should advantageously be 5-10 times the size of the total flow cross section of all the injection openings of the fuel injection valve. In this way, pressure losses caused by throttling action as the fuel flows through the fuel inlet conduit are averted. It is especially advantageous to make the flow cross section at the fuel inlet and at the fuel outlet of the fuel filter the same size as or slightly larger than the flow cross section of the region of the fuel inlet conduit adjoining the fuel filter downstream. Throttle losses at the fuel filter can thus be reliably precluded. A further advantage is attained by reducing the number of longitudinal grooves in the filter body from six grooves to four. In this way, once again, the idle volume at the end of the filter and the throttle losses as the fuel flows between the individual longitudinal grooves of the two groups can be reduced. The longitudinal recesses on the fuel filter can be embodied either as longitudinal grooves or as faces. To reduce the pressure losses as the fuel enters the fuel filter, an inlet chamfer is advantageously provided at the upper end face of the fuel filter as well. To reduce the idle volume in the fuel inlet conduit, the filter body of the fuel filter also, on its lower, outlet-side end, has a stop cone, with which the fuel filter rests on a conical seat face, complementary to the stop cone, of the inlet conduit. For connecting the longitudinal grooves that are open on the injection side to the fuel inlet conduit, two oblique polished sections are made in the stop cone face of the fuel filter, which originate at the end face toward injection of the fuel filter and discharge into the group of longitudinal grooves that are open toward the injection opening. The conical seat face in the fuel inlet conduit and the stop cone face on the fuel filter cooperating with it are advantageously embodied with a cone angle between 45 and 90°. It is furthermore especially advantageous to embody the oblique polished sections in the stop cone face with this kind of cone angle as well.
Further advantages and advantageous features of the subject of the invention can be learned from the specification, drawing and claims.
REFERENCES:
patent: 1157315 (1915-10-01), Lemp
patent: 1964218 (1934-06-01), Schargorodsky
patent: 2067131 (1937-01-01), Schlaupitz
patent: 3499605 (1970-03-01), Dreisin
patent: 5360164 (1994-11-01), Pape et al.
patent: 5365906 (1994-11-01), Deweerdt
patent: 5421306 (1995-06-01), Talaski
patent: 5584999 (1996-12-01), Cooke
patent: 5879553 (1999-03-01), Fulford
patent: 5996908 (1999-12-01), Hofmann et al.
Greigg Edwin E.
Greigg Ronald E.
Miller Carl S.
Robert & Bosch GmbH
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