Fluid sprinkling – spraying – and diffusing – Including valve means in flow line – Reciprocating
Reexamination Certificate
1999-07-19
2001-05-15
Scherbel, David A. (Department: 3752)
Fluid sprinkling, spraying, and diffusing
Including valve means in flow line
Reciprocating
C239S596000, C239S424500
Reexamination Certificate
active
06230992
ABSTRACT:
BACKGROUND INFORMATION
The production of nozzles in the form of perforated disks representing “S-type disks” is described in European Patent Application No. 0 354 660. According to this method, the inlet and outlet openings in the perforated disk are offset from one another, thus inevitably producing an “S pattern” in the flow of a fluid passing through the perforated disk. The proposed perforated disks are formed by two flat silicon wafers that are bonded together. Regions with a reduced thickness are provided on the silicon wafers so that shearing gaps are formed between the openings of the first wafer and the one opening of the second wafer parallel to the end faces of the wafers. The silicon wafers, which have a large number of perforated disk structures, are etched using known photomasking techniques, thus creating the inlet and outlet openings. The truncated tapered contours of the openings in the perforated disk logically result from the non-isotropic etching technique.
A fuel injection valve that has a nozzle composed of two silicon wafers on its downstream end is described in U.S. Pat. No. 4,907,748. As with the perforated disks described above, the inlet and outlet openings in the two silicon wafers are offset from one another, thus producing an “S pattern” in the flow of a fluid passing through the disk, which is fuel in this case.
In addition, perforated disks composed of two or three connected silicon wafers are described in German Patent Application No. 43 31 851. In this publication, an upper inlet opening in the upper wafer is followed by multiple outlet openings in the lower wafer with complete coverage. The perforated disks are provided for spraying a fuel-gas mixture with gas inflow channels from which a gas strikes the fuel to be sprayed largely perpendicularly.
All of the above-described perforated disks made of silicon have the disadvantage that they may not be sufficiently resistant to fracture because silicon is brittle. Especially when permanent loads are placed, e.g., on an injection valve (engine vibrations), there is the danger that the silicon wafers will break. Mounting the silicon wafers on metal components, such as injection valves, is complicated, since special stress-free clamping solutions must be found, and sealing the valve is problematic. It is not possible, for example, to weld the silicon perforated disks onto the injection valve. There is the further disadvantage of the edges of the openings in the silicon disks being worn away by the frequent passage of fluid.
The provision of a spray disk having multiple spray holes as well as an atomizer disk located further downstream is described in International Patent Publication No. 95/25889. The spray holes are provided in a central conical depression in the spray disk. This spray disk is followed by a completely separate atomizer disk, which is composed of multiple layers or wafers and into which air flows from the outside through a special opening geometry. The stainless steel wafers of the atomizer disk have an inner, central passage in which the air strikes, largely perpendicularly, the fuel emerging from the spray holes of the spray disk.
SUMMARY OF THE INVENTION
The perforated disk or atomizer disk according to the present invention and the injection valve according to the present invention have the advantage that especially uniform, extremely fine atomization of a fluid can be provided with the aid of a gas, thus achieving an especially high atomization quality and a jet shape that is adjusted to the requirements at hand. Consequently, the use of a perforated disk or atomizer disk of this type on an injection valve of an internal combustion engine makes it possible, among other things, to reduce the exhaust emissions of the internal combustion engine and also reduce fuel consumption.
Using electrodeposition techniques, it is possible to advantageously produce in a reproducible manner a very high volume of perforated disks or atomizer disks extremely precisely and economically. This production method also permits a very large amount of design flexibility because the contours of the openings in the perforated disk can be freely selected. Particularly in comparison to the production of silicon disks, electrodeposition has the advantage that a wide variety of materials can be used. The many different metals with their various magnetic characteristics and hardnesses can be used for producing the perforated disk or atomizer disk according to the present invention.
Multilayer electroplating makes it possible in an especially advantageous manner to produce recesses economically and with extreme precision.
Another advantage is that the perforated disks produced by electrodeposition are designed in one piece, since the individual functional plates are built upon each other in directly subsequent deposition steps. After electrodeposition, the perforated disk is in one piece; this means that no time and cost-intensive process steps are needed for joining the individual nozzle wafers. This also eliminates problems which can arise when centering or positioning individual wafers in relation to each other in multi-piece perforated disks.
An arrangement for supplying gas can be advantageously provided very easily and at no additional expense in a perforated disk or atomizer disk of this type produced by electrodeposition. Gas flows through this gas supply arrangement in the direction of the fuel to be sprayed, atomizing the fuel especially finely. In addition to optimum preparation and atomization of the fuel, the gas inflow pulse also affects the direction of the fuel jet at the outlet. A high impulse, for example, causes the enveloping angle of a conical fuel jet to decrease. This effect can be used to control the jet shape according to load. With a low engine load, at which a vacuum is produced in the intake manifold due to the throttle valve position, the driving pressure drop for the surrounding gas is high, restricting the jet volume. With a high engine load, broader jet patterns with larger cone angles can be produced in this manner. Depending on the local distribution of the fuel input into the combustion chamber of an internal combustion engine, a level of combustion that is ideal for the working load can be achieved by the gas-controlled influence on the jet pattern. Selecting different opening geometries in the perforated disk makes it possible to influence this jet pattern even when spraying a fan jet or using an asymmetrical jet shape.
It is also advantageous to design the perforated disks according to the present invention in the form of S-type disks so that exotic, unusual jet shapes can be produced. These perforated disks provide countless variations of jet cross-sections for one-, two-, and multi-jet sprays, including rectangles, triangles, crosses, and ellipses. These unusual jet shapes allow the spray to be optimally adjusted precisely to predetermined geometries, e.g., to different intake manifold cross-sections of internal combustion engines. This makes it possible to advantageously customize the use of the available cross-section to homogeneously distribute the injected mixture in a manner that reduces emissions and to avoid harmful film deposits on the wall of the intake manifold caused by exhaust gas.
The jet pattern can be easily varied. For example, it is simple to produce flat or conical jet patterns, those that include multiple individual jets, and asymmetrical jet patterns (directed to one side).
An asymmetrical, e.g., one-sided, gas supply can very effectively divert the fuel jet to one side. This can be advantageous if fuel is to be always sprayed onto an intake valve at a specific angle each time a working load is applied.
It is also advantageous to design the atomizer disks according to the present invention in the form of swirl disks in order to achieve especially effective atomization of the fluid to be sprayed. Because the gas supply openings as a means for supplying the gas empty into the outlet opening tangentially rather than radially, an additional swirling motion
Arndt Stefan
Heyse Jorg
Maier Martin
Hwu Davis
Kenyon & Kenyon
Robert & Bosch GmbH
Scherbel David A.
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