DE2708824A1 - Fuel air mixing and metering system - has gas fed to chambers formed between two plates located downstream to air distributor plate - Google Patents

Abstract

The air induction piep downstream to the filter has an intake restrictor consisting of a distributor plate and a rotatable cover plate. Both plates have the same number of equally distributed air intake openings. By turning the cover plate the induction air volume can be regulated. Two plate s are arranged at a distance from each other and 5cm below the distributor plate to extend across the intake. The plates are joined to each other by tubes passing through borings. The tubes conduct the air to the spaces between the plates. An annular channel (12) extends around the induction pipe at the height of the two plates. The channel which has a fed union for the combustion gas, is provided with a number of openings leading to the chambers between the two plates. The gas leaves the chambers via exit openings formed in the top plate.

Description

Device for dosing and mixing fuel gas and air

for the operation of internal combustion engines The invention relates to a Device for dosing and mixing fuel gas and air for the operation of internal combustion engines, with a throttle device arranged in the intake line of the internal combustion engine for one component of the fuel gas / air mixture, one between the throttle device and the inlet of the internal combustion engine open laterally into the intake line Feed for the other component and a metering device arranged in the feed.

If internal combustion engines are operated with a fuel gas, then stands one faces the difficulty that the fuel gas and the air with different pressures pending on the intake line of the internal combustion engine. Most of the time the air just has to be sucked through an air filter so that they are practically at the constant atmospheric pressure flows into the suction line.

The fuel gas 3edoch must be taken from pressure vessels or in a gas generator are generated, the pressure of the fuel gas decreasing with increasing fuel gas extraction.

This occurs in particular in internal combustion engines with so-called Cracked gas generators are operated. Included it is catalytic Reactors in which liquid fuel containing hydrocarbons evaporates or is sprayed and converted with primary air through partial oxidation into a fuel gas will. Such a method has the advantage that the resulting fuel gas in the Internal combustion engine can be burned so that only a small emission of pollutants (unburned hydrocarbons, anti-knock residues or oxides of oxides) with the exhaust gas are emitted. To achieve good combustion of the fuel gas, it is necessary that the fuel gas before it is fed into the internal combustion engine is mixed as homogeneously as possible with the combustion air. The devices for Dosing and mixing of the components to be added are to be designed, if possible, in such a way that that only small pressure losses occur in order not to reduce the engine fill unnecessarily.

From the German Offenlegungsschrift 22 32 656 is a device known, which is arranged at the entrance of such a gap gas generator and to it serves, the fuel used with the necessary gasification air as homogeneously as possible to mix. In the supply line for the gasification air is a vertical one pipe system extending over the flow cross-section to the direction of flow arranged, which has a large number of evenly distributed over the flow cross-section, Has outlet openings opening perpendicularly into the air stream. At the outlet openings are connected to gas guide surfaces, which extend up to the immediate vicinity of the catalytic converters of the gas generator and a Venturi nozzle-like expansion of the flow cross-section cause.

The air flows through the mixer in a laminar flow and one a good mixture is achieved that the gasoline through the many fine outlet openings is distributed over the entire flow cross-section.

Another mixing device that is also at the entrance of a Gap gas generator is arranged and for mixing several gaseous and / or vaporous Substances is used, is off the German Auslegeschrift 23 59 587 known. A box-shaped hollow body is in the line for one component a laterally opening into the hollow body feed nozzle inserted through the a multitude of parallel tubes provided with a multitude of openings, get lost. Here, too, the mixing is achieved by the fact that the Component divided into many partial flows via the large number of openings in the pipes and is supplied perpendicular to the main flow direction.

These known devices are each gasification air and fuel vapor fed. The two components are applied with approximately the same pressure.

A device for mixing is disclosed in German patent specification 176 185 known from steam or gaseous fuels with air, in which in the fuel gas line two extending over the entire flow cross-section, one behind the other at a distance arranged plates are used. The plates contain holes and in them Holes are inserted that the fuel vapor through the plates and the tubes guide intermediate space. A runs laterally around the gap Ring channel for the supply of air, which runs along the circumference of the fuel gas line arranged mouth openings opens into the space. Lead from the space in between Outlet openings in the fuel line, the outlet openings only in the Fuel flow facing away from the side are provided. Air and fuel vapor flow through the mixing device in a parallel direction. For metering the air is provided the mouth openings by a rotatable ring with matching to the mouth openings Openings partially cover and the passage cross-section of the mouth openings can be changed by turning the ring.

From US-PS 3,023,775 a throttle device is known, which from a base plate with through openings distributed over the base plate and a Cover plate with entry openings matching openings consists. By turning the cover plate, the passage openings become partially over covers and thereby their passage cross-section is reduced. This device enables precise throttling and metering of flowing media, especially for high pressure.

The invention is based on the object of providing a compact as possible Specify device of the type specified, in which the means for dosing and mixing the individual components in such a way that on the one hand the lowest possible pressure loss, and on the other hand the best possible mixture.

This object is achieved according to the invention in that as a throttle device a distributor plate with a plurality of through openings and one on the Distributor plate arranged rotatable cover plate with to the passage openings suitable Durchläßgn are provided. The feed ends in a the suction line extending perpendicular to the flow direction line system. The distance between the throttle device and the pipe system is 2 to 10 cm. The line system has outlet openings which are directed towards the throttle device are.

The passage openings in the distributor plate divide the one flowing Component in a large number of partial flows, which over the entire flow cross-section are distributed. The size and / or number of the passage openings can be advantageous also increase a little towards the edge of the distributor plate in order to reduce the braking effect to compensate for the wall and to achieve that also close to the wall in the suction line there is sufficient throughput. Compared to usual throttle valves that are arranged pivotably about an axis lying transversely to the flow direction and diverting the gas flow out of its direction of flow creates such a distributor plate a more even distribution of the flow and causes less turbulence, so that the resulting Flow resistance lower is. The distance between the throttle device and the pipe system is selected so that that the turbulence arising behind the throttle device still extends to the pipe system are sufficient. Through outlet openings directed at the throttle device now the other component is fed directly into the vortex spaces of this turbulence, so that there, taking advantage of the inevitable at the throttle device Turbulence a turbulent mixture is created.

It is not necessary. that the outlet openings particularly are narrow and the second component is injected particularly finely, which increases the Would cause pressure loss for this second component.

In known mixing devices in which the component to be admixed is mixed in perpendicular to the main flow direction, there is often the risk of that the component to be admixed initially in strands next to the other component flows along and only slowly or only through other turbulence-generating means mixing can be achieved. This danger exists with the device according to the invention not and there are also no further turbulence-generating means necessary, which would increase the total pressure loss occurring. Also draws the device is characterized by a particularly short overall length.

Advantageously protruding into the suction line as a line system Pipes may be provided. However, two can also be perpendicular to the direction of flow Be provided over the entire flow cross-section extending plates in the Are arranged spaced behind one another and have bores. In the holes pipe pieces are used as flow channels for one component, the enforce the plates and the space between breathing. To the other To feed component, it is provided that the feed of the other component leads into the space between the plates and that only that of the throttle device facing plate has outlet openings.

It is advantageous if the feed line is a suction line enclosing annular channel, which is distributed along the circumference of the suction line, has mouth openings leading into the line system. On the circumference of the suction line a rotatable ring is provided as a metering device, which leads to the mouth openings has suitable openings. The mouth openings and the matching ones are preferred Openings in such a way partially designed as slots that by turning the ring the passage cross-section of the individual mouth openings changed differently to be able to.

With the help of two exemplary embodiments and three figures, the essence becomes the invention explained in more detail.

In the embodiment of FIG. 1, 1 is the air filter referred to the intake line leading to the inlet of the internal combustion engine. Below the The throttle device, which consists of the distributor plate 2, is located on the air filter and the rotatable cover plate 3 above it. Via the distribution plate is a plurality of passage openings 4 evenly distributed and in the cover plate above each of these passage openings 4 there is a passage of the same size 5.

In the position shown, come from the cover plate and distributor plate Passages and passages to lie exactly on top of one another. With a twist the cover plate, however, the passage openings are partially from the distributor plate covered so that the passage cross-section can be changed by turning the cover plate is.

Between the throttle device and the inlet of the internal combustion engine two plates 7 and 8, which are arranged one behind the other at a distance, extend through the suction line. In bores 9 of the plates 7 and 8 pipe sections 10 are etched, the intake air through the plates and the space between the plates 11 direct. The distance between the upper plate 7 and the distributor plate 2 is about 5 cm.

At the height of the plates 7 and 8 runs around the suction line Annular channel 12 to which a feed nozzle 13 for the fuel gas, preferably the Cracked gas of a cracked gas generator. The ring channel 12 opens out via a A plurality of mouth openings 14 in the space 11 between the two plates 7 and 8. The fuel gas flowing in through the supply port is released from the space 11 passed into the air stream by means of a plurality of outlet openings 16, the outlet openings 16 are only arranged in the upper plate 7.

Preferably, the outlet openings 16 are arranged so that they the passages 4 are opposite.

The arrows 17 indicate the flow of the intake air.

Arise between the metering device and the feed system here eddies in the air flow and the fuel gas becomes, as indicated by the arrows 18 is indicated, introduced directly into the vortex spaces of the air flow.

In order to meter the amount of fuel gas to be supplied, is in the ring channel an adjustable ring 20 is arranged. This ring 20 carries to the mouth openings matching openings 21.

FIG. 2 shows a cross section through the device according to FIG. 1.

Circular holes 14 of the same size are provided as outlet openings, which, however, is not strictly evenly distributed along the circumference of the suction line are. Rather, they are on the part of the ring channel that the air supply nozzle opposite, the mouth openings closer to one another than on the air duct neighboring part. This distribution of the mouth openings was chosen so as to reduce the To compensate for the asymmetry caused by the one-sided fuel gas supply in such a way that that the same amount of fuel gas flows into the space from about all sides.

The openings 21 in the adjustable ring 20 are chosen so that in the position shown in FIG. 2, they each cover the entire cross section of the mouth openings release. While on the side of the suction line circumference adjacent to the supply nozzle the Openings the size and shape of the orifices are on the opposite side Side, however, provided as openings slots 22. By turning the Ring is now achieved that while twisting the free passage cross-section of the M: inlet openings adjacent to the feed nozzle is reduced, however the mouths on the opposite side from the slots 22 cannot be covered. This configuration of the mouth openings and slots ensures that even with a low fuel gas throughput always a sufficient one Part of the fuel gas on the side opposite the mouth opening into the Interspace flows in.

To compensate for the asymmetrical inflow of the fuel gas into the ring channel, it can also be advantageous not to distribute the openings 21 on the ring 20 in such a way that that / 0 + e mouth openings 14 exactly cover. Rather, they are kind of one The vernier is distributed in such a way that when it rises, the muzzle openings that are in the vicinity of the connecting piece 13 are hardly covered and thus only a small passage cross-section release, but come to rest on the opposite side.

By turning the ring, the passage cross-section can be adjusted in other positions enlarged in the vicinity of the nozzle 13 and decreased on the opposite side will.

The rotation of the cover plate 3 and the ring 20 can depend on from the gas pedal of the internal combustion engine, e.g. by means of Bowden cables (not shown) be made.

In the embodiment of the device according to FIG. 3, the line system a system of pipes 31 is provided which, from the annular channel 30, perpendicular to the direction of flow protrude into the intake line and openings directed towards the throttle device 32 for the fuel gas. The mouth openings 35 between the annular channel 30 and the tubes 31 can again by an adjustable ring 36 with corresponding Openings 37 are partially covered. The distance between the pipes and the Distribution plate is only about 2 cm, eo that the one on the distributor plate generated turbulence continue downstream to below the pipes. In this Trap, further outlet openings 33 can also be provided at the pipe ends, through which the fuel gas flows out perpendicular to the main flow direction. The turbulence create a sufficient mixture in this fold too.

6 claims 3 figures

Claims (6)

Claims device for dosing and mixing fuel gas unO air for the operation of internal combustion engines, with one in the intake line the internal combustion engine arranged throttle device for one component of the Fuel gas / air mixture, one between the throttle device and the inlet of the Internal combustion engine laterally in the intake line opening supply for the other Component and a metering device arranged in the feed, characterized in that that as a throttle device a distributor plate (2) with a plurality of passage openings (4) and a rotatable cover plate (3) arranged on the distributor plate to the Passage openings matching passages (5) are provided that the feed (13) into a suction line extending perpendicular to the direction of flow Line system (11) leads to the fact that the distance between the throttle device and the line system 1 to 10 cm and that the line system directed towards the throttle device Has outlet openings (16). 2. Apparatus according to claim 1, characterized in that the line system Pipes (31) projecting into the suction line are provided. 3. Apparatus according to claim 1, characterized in that the line system two each perpendicular to the direction of flow over the entire flow cross-section extending plates (7, 8) arranged one behind the other at a distance are provided, that the plates have bores (9) that in the bores the gap (11) Pipe pieces (10) penetrating between the plates as flow channels for the one Component are used that the mouth (14) of the feed for the other component in the space (11) between the plates and that only that of the throttle device facing plate (7) has outlet openings for the other component. 4. Apparatus according to claim 2 or 3, characterized in that the feed an annular channel surrounding the suction line (12) contains that the ring channel distributed along the suction line circumference, in the line system has leading orifices (14) and that on the circumference of the suction line as a metering device a rotatable ring (20) with openings (21) matching the mouth openings (14) is arranged. 5. Apparatus according to claim 4, characterized in that the mouth openings (14) and the opening (21) do not strictly overlap but rather like a nonius are arranged shifted to each other. 6. Apparatus according to claim 4 or 5, characterized in that the mouth openings (14) and the matching openings (21) in this way partially are designed as slots (22) that the passage cross-section by rotating the ring (20) the individual mouth openings can be changed differently.