DE3413419C2 - - Google Patents

Description

The invention relates to a device for initiating additional gas flows into the intake duct of a carburetor engine the features specified in the preamble of claim 1.

Such a device is from DE-PS 24 02 970 as an additional device known for mixture-compressing internal combustion engines with carburettors. The known device serves the fuel, which is in the Intake duct downstream of the throttle valve on the intake duct wall as Condensate precipitates to lift off the wall of the intake duct, nebulize and mix well To achieve a fuel-air mixture. Because of this are downstream of the throttle valve in the wall of the intake duct two opposing slots arranged through which Additional air flows into the intake duct. The slots are like this dimensioned and the amount of additional air that the slots is fed through a special, second throttle valve, their position from the position of the throttle valve of the carburetor depends, controlled so that the additional air already in the slots Transition area from idle to partial load operation of the Internal combustion engine at very high speed, and in Partial load operation of the internal combustion engine even approximately Sound velocity escapes.

This can be achieved by having the cross section of the Supply lines that lead the additional air to the slots with  provides a cross section which is larger than the common one Opening cross section of the slots, so that the slots of one determined degree of opening of the second throttle valve as Act cross-section, d. H. from then on the only limitation for the Form the flow rate of the additional air.

The known device ensures that the second Throttle valve, which controls the amount of additional air, already at low speed opens, so that the flow of the additional air through the slots from low speeds to one predetermined speed increases steadily in the medium speed range. From this average speed, the air throughput remains Slots are practically constant. This makes it practical the entire speed range of such a device equipped internal combustion engine a good efficiency and a achieved a low proportion of nitrogen oxides in the exhaust gas. This is because that practically a relatively lean over the entire speed range Mixture is burned. Because of the excess air in this mixture, which can be of the order of about 20%, the Ver reduction in nitrogen oxide levels in the exhaust gas reached during at the same time the internal combustion engine with wear-friendly, can work at relatively low temperatures.

Working with excess air is made possible by the fact that with additional air flowing out of the slots at high speed the intake duct wall detaches the fuel condensed there and atomized and the fuel-air mixture homogenized. It also has the known device has a favorable influence on the Fuel consumption because of working with excess air used fuel can be burned more completely than without  such a device.

The above statements on that from DE-PS 24 02 970 known device meet in the same way device according to the invention.

In the known device according to DE-PS 24 02 970 Openings of the opposing slots below the Throttle valve asymmetrical to the longitudinal direction of the throttle valve shaft is provided, whereby the through the crescent-shaped openings of the Throttle valve in the intake duct flows through the air Air flows emerging from the slots are detected unevenly will. This could result in a below the throttle valve condensate deposited on the intake duct wall through the Air flows out of the slots unevenly or with a delay is degraded, especially when changing load ranges the processing of the toxic components in the exhaust gas is restricted would.

Starting from a device for introducing additional Gas flows according to the known type described above, is the Invention based on the object, the proportion of toxic components in the exhaust gas.

This object is achieved by a device with the Claim 1 specified characteristic features.

Advantageous developments of the invention are the subject of Subclaims.  

The essence of the invention is the slots in the intake duct Arrange geometrically so that they are in the intake duct in the area of maximum condensate formation, especially symmetrical the sickle-shaped openings of the throttle valve. So far a symmetrical preparation of the below the throttle valve present condensate without risk of part of the condensate could deposit unevenly on the intake duct wall and there at high condensate formation in the partial load range at all could not be dismantled or only with delay.

The number of slots should be at least two; in this Fall is one of the slots on one side and the other Slot on the other side of the imaginary division area of the Exhaust duct. But it can also on each side of the division area multiple slots may be provided. The slots can all with the same gas, e.g. B. with additional air or with exhaust gas or with a other gas mixture are supplied. But it is entirely possible to supply different slots with different gas flows, e.g. B. a slot with exhaust gas and another slot with Additional air.

The invention makes use of the observation that it is close to the throttle valve in the intake duct of the internal combustion engine the fuel - as far as it is is an internal combustion engine with carburetor - mainly in that peripheral region of the intake duct on the intake duct wall where the opening width of the gap between the Throttle valve and the intake duct wall is largest, i.e. in the Middle between the ends of the throttle valve shaft. Because the gap between the throttle valve and the intake duct wall near the ends the throttle valve shaft in the lower and middle part-load range Internal combustion engine is relatively narrow, there can only be one relatively  small amount of the fuel-air mixture pass through and therefore only a relatively small amount of fuel in the corresponding peripheral area of the intake duct wall in the vicinity the throttle valve condense. Slots for additional air, which in the same circumferential area as the ends of the throttle valve shaft are arranged, therefore contribute to the atomization of the fuel and not much for the homogenization of the fuel-air mixture. Therefore, according to the invention, the slots are closed in this way orient that they are in those two circumferential areas of the Intake duct wall lie where the opening width of the crescent Slots between the throttle valve and the intake duct wall on is largest and most fuel on the intake duct wall precipitates. With this orientation, the slots can be their develop greatest effectiveness.

In the prior art, the orientation of the slots has to be considered with respect to the position of the throttle valve shaft in the intake duct so far no consideration.

The inventive orientation of the slots in the intake duct leads to a noticeably better mixture preparation, which a more complete combustion and lower levels of poison gas in the exhaust gas has the consequence.

To reduce the proportions of toxic components in the exhaust gas additional air advantageously arranged in the slots arranged according to the invention, Exhaust gas or fission gas supplied, with the intake duct of the engine in Connection to the slots a connecting line is provided and through a homogeneous mixture with the fresh combustion air he follows.  

The recirculation of exhaust gas into the intake duct Internal combustion engine is not only useful for such Internal combustion engines with an injection of fuel work, it can also be used with particular advantage at Internal combustion engines which are equipped with carburetors. For this is the supply line for the gas which is fed to the slots is branched off from the exhaust line of the internal combustion engine and into this A heated catalyst, e.g. B. based on platinum or arranged on a nickel basis, whereby by chemical-catalytic Implementation of the water vapor contained in the recirculated exhaust gas stream with other reactive components of the exhaust gas, e.g. B. with not yet completely burned hydrocarbons Energy supply hydrogen is generated. So it won't be one simple exhaust gas recirculation proposed, but a recirculation of fission gas obtained catalytically from exhaust gas; the hydrogen, the is contained in the cracked gas, improves the ignitability of the by the exhaust gas recirculation lean air-fuel mixture and thus allows the mixture to become leaner than without it catalytic treatment of the exhaust gas would be possible.

The return of cracked gas has the advantage that by heating of the fuel-air mixture in the partial load range Lower fuel consumption due to reduced throttle losses can be and that you can safely ignite and burn the lean fuel-air mixture achieved. In the result gets therefore, a reduced proportion of poison gas in the exhaust gases at the same time reduced fuel consumption.

The cracked gas causes both when flowing through the slots  dynamic and thermal processing of the fuel condensate in internal combustion engines with a carburetor connected to a Homogenization of the entire mixture, and by the contained Hydrogen is a safe ignition.

In the case of internal combustion engines without a carburetor, this is of course not necessary Preparation of the fuel condensate on the intake duct wall, yes also leads to the homogenization of the exhaust-air mixture improved combustion. But they work in all cases Recycle of cracked gas and the arrangement of the slots in the Intake duct in the sense of a combination together.

The device according to the invention is also suitable for retrofitting of internal combustion engines. When used on internal combustion engines with Carburettor you can have a flat bottom part on the bottom of the carburetor, in particular attach a plate in which a hole is provided which forms part of the intake duct and in which the Slits and part of the supply line to these is formed. The Device can be fairly simple and inexpensive if one has the Slots and the feed line in the top of the lower part, e.g. B. incorporated by milling and this lower part then on the underside attached to the carburetor, causing the bottom of the carburetor to pass through the milling or the like formed covers and closed functional slots and to a functional supply line added.

In the following the invention is based on two embodiments play explained in more detail. It shows  

Fig. 1 shows a device for treatment of liquid fuels for internal combustion engines with a carburetor mixture-namely a section along the line II in Fig. 2 by the carburetor base,

Fig. 2 shows the longitudinal section II-II through the embodiment illustrated in FIG. 1 device,

Fig. 3 shows the schematically drawn extraction of fission gas from the exhaust gas of the internal combustion engine.

In the embodiment shown in FIGS. 1 to 3, a flat additional part 3 is flanged to the underside of the carburetor 1 of the internal combustion engine 11 , in which a circular passage is provided as a continuation of the intake duct 39 of the carburetor. The water circular passage is surrounded by two opposite and extending in Umfagnsrichtung the suction channel 39 , circular segment-shaped slots 9 and 10 , which a gas, for. B. air, exhaust gas or a cracked gas is supplied. The supply line consists of a two slots 9, 10 ver binding, largely enclosing the intake duct ring channel 8 and an adjoining, flat in the additional part 3 channel 7 , which extends into an additional part 3 channel 7 , which is in an additional part 3 attached connection piece 4 continues, in which a throttle valve 5 is arranged. A pipe 6 and possibly further feeder sections 14, 15, 19 and 20 are connected to the connecting piece 4 .

This throttle valve 5 is closed when the internal combustion engine is idling; their position depends on the negative pressure in the intake duct 39 and for this purpose the throttle valve 5 can be in mechanical connection with the throttle valve 2 of the carburetor 1 in such a way that it is opened when the throttle valve 2 loads during the transition from idle operation to part - and full load operation is opened.

One could also control the throttle valve 5 by means of a vacuum box, which responds to the vacuum in the intake duct 39 . The throttle valve 2 of the gasifier is located upstream of the slots 9, 10 close to these in the intake duct 39 .

The gas entering through the open throttle valve 5 in the direction of arrow 22 is drawn in by the internal combustion engine and flows through the channel 7 and the annular channel 8 . In the region of the channel 7 there is a division of the gas flow, which flows in part in the direction of arrow 23 through the slot 9 into the suction channel 39 , while the other gas flow with a slight time delay in the direction of arrow 24 through the opposite slot 10 flows into the intake duct 39 .

As can be seen from the illustration in Fig. 1 with respect to the arrows 23 and 24 shown , the two circular segment-shaped slots 9, 10 are arranged diametrically opposite one another, symmetrically to the axis of the throttle valve shaft 21 parallel to itself by shifting the longitudinal axis along of the longitudinal center line of the intake duct 39 , imaginary parting surface of the intake duct 39 (which is a plane in the case of a cylindrical outlet duct). The straight line connecting the two centers 40, 41 of the slots 9 and 10 intersects this imaginary parting surface at a right angle. Downstream of the throttle valve 2 is reflected on those regions of the wall of the intake passage 39, where in the partial load operation, that is at a lower opening to approximately a _^3/4 --Luftge fuel is mixed opening of the throttle 2, the greatest width of the crescent-shaped passages for the , the largest proportion of fuel condensate sat, and precisely in these areas inventively, the two slots 9, 10 are arranged.

On both sides of the throttle valve shaft 21 form naem Lich when opening the throttle valve 2 between this and the wall of the intake duct 39 first narrow and then widening sickle-shaped openings through which the fuel-air mixture flows. At partial load operation, these openings are so narrow that the mixture must squeeze through so close to the intake duct wall that the fuel contained in the mixture condenses in part on the intake duct wall.

Since the two formed between the throttle valve 2 and the intake duct wall crescent-shaped openings close to the ends of the throttle valve shaft 21 are very narrow, there is very little Ge mix and thus fuel passes through. A condensate treatment at that point of the intake duct circumference, for. B. by a circumferential ring slot, would bring only about half of the flow energy in the auxiliary gas at the correct and necessary points to effect and bring the treatment effect in the lower part of the part-load operation (e.g. in city traffic) to a minimum.

Accordingly, the inventive design and geo metric arrangement of the slots 9, 10 in the intake duct wall depending on the orientation of the throttle valve shaft 21 and the location of the maximum condensate formation is very important.

The slots 9 and 10 are so be measured in cross section that even from a low speed of the internal combustion engine 11, the throttle valve 5 releases a larger passage and therefore no longer acts as a cross-section limiting the gas throughput in the connecting piece 4 .

The tube 6 , the channel 7 and the ring channel 8 have a larger passage cross section than the slots 9 and 10 and therefore the latter act as a measuring cross section (ie as the only limitation) for the gas throughput from about a driving speed of 80-100 km / h, whereby the gas emerging from slots 9 and 10 reaches speeds of 100 m / s and more.

A particularly good thermal efficiency of the internal combustion engine, a further reduction in the fuel requirement and a further reduction in the amount of poisonous gas in the exhaust gas are achieved if, instead of additional air, a fission gas generated by catalytic treatment of some of the exhaust gases is connected via the pipe 6 and the connecting piece 4 leads to the slots 9 and 10 . The internal combustion engine 11 shown in FIG. 3 has an exhaust manifold 12 which merges into the exhaust silencer via a flange 13 in a manner not shown. From the exhaust gases flowing in the exhaust manifold 12 in the direction of arrow 27, a part is branched off in the region of the flange 13 in the direction of arrow 28 , which flows there into a channel 14 , which forms the entrance to a thermal-catalytic reactor 15 on the rear on the Flange 13 is attached.

In the reactor 15 is a heating wire is attached from a catalytically active metal 16, the z via electrical lines 17 and 18 with electrical energy. B. is powered by the car battery. The energy supply and the simultaneous action of the catalyst on the recirculated exhaust gases result in a chemical-catalytic reaction of the water vapor contained in the exhaust gases with the unburned hydrocarbons and carbon monoxide residues still present in the exhaust gases, as a result of which hydrogen is released.

The outlet port 19 of the reactor 15 is connected via a connecting line 20 to the tube 6 of the gasifier attachment 3 . In the connecting line 20 , the gap gas flows in the direction of arrow 29 .

The inner surface of the reactor 15 can for better catalytic action of the reactor with a material acting as a gap catalyst such. B. nickel. It is also advantageous if the reactor 15 is supplied not only with exhaust gases, but also with combustible auxiliaries such as natural gas or alcohol, but in particular gasoline; this means that a larger proportion of the water vapor contained in the exhaust gases can be converted chemically to produce hydrogen, the hydrogen favorably influencing the combustion process.

Instead of a thermal-catalytic reactor 15 , it would also be possible to provide a gap catalytic converter, which is expediently heated electrically and which consists of a gas-permeable body made of a ceramic (e.g. made of Al ₂ ) coated with catalytically active metal (e.g. platinum or nickel) O ₃ ) best hen, which is housed in one of the exhaust gases flowing through the chamber. The flowing in the direction of arrow 22 in the channel 7 auxiliary gas, in particular fission gas, unfolds a strong condensate-removing effect at the slots 9, 10 lying opposite one another, that is, the channel 39 crawling along the wall of the Ansaugka fuel condensate is in the direction of the arrows 25 and 26 finely nebulized and lifted off the wall of the intake duct 39 . This achieves a dynamic and thermal fine atomization of the fuel and a homogenization of the fuel-air mixture; If a cracking gas is added as the auxiliary gas, then because of the hydrogen content in the cracking gas, good ignition of a mixture that is so emaciated that it would hardly be ignitable without the cracked gas being carried out is achieved. In addition, the nitrogen oxides NO _x in the exhaust gas are drastically reduced by the recirculation of non-combustible nitrogen from the exhaust gas into the additional gas component 3 .

According to investigations carried out with the addition of hydrogen in part-load operation of a gasoline engine, only approx. 1 kg of hydrogen is required for 25 kg of gasoline in order to achieve very low proportions of CO, hydrocarbons and NO _x in the exhaust gas. This amount can be from about ^{_one quarter} of the water vapor content in the exhaust gas by catalytically-chemical conversion gain.

Preferably, the exhaust gas recirculation through the slots 9, 10 is limited so that the demand for hydrogen in the recirculated exhaust gas corresponds to an amount that arises at a driving speed of 80-100 km / h.

As an example: a modern mid-range car requires an output of approx. 18 KW at a driving speed of 100 km / h. With the mixture preparation according to the invention, about 4 kg of gasoline per hour are used for this purpose. The slots 9, 10 are dimensioned such that 0.04 kg of hydrogen take the way through the slots 9, 10 with the recirculated exhaust gas. At higher loads (engine power), the relative hydrogen content in gasoline decreases, at lower power the amount of exhaust gas supplied is controlled by means of the throttle valve 5 . Thus, in the main driving area at partial load operation, there is a high exit velocity of the recirculated gas at the slots 9, 10 and thus a good treatment of the gas condensed on the intake duct wall and a homogeneous mixing of both gas flows in the intake duct 39 . This is very important, so that all cylinders of the internal combustion engine 11 receive an evenly composed fuel-air-auxiliary gas mixture.

Claims (4)

1.Device for introducing additional gas flows into the intake duct of a carburetor engine by means of opposing slots in the intake duct wall, downstream of the throttle valve, which extend in the circumferential direction of the intake duct over a circumferential angle of less than 180 ° and to which the additional gas is supplied through one or more feed lines The longitudinal axis of the throttle valve shaft passes through the area of the walls not interrupted by the slots and a control element, in particular a further throttle valve or a valve, is provided in each supply line to control the throughput of the additional gas through these supply lines depending on the negative pressure prevailing in the intake duct characterized in that the slots ( 9, 10 ) in the area of maximum condensate formation are symmetrical to a plane generated by shifting the longitudinal axis of the throttle valve shaft parallel to itself along the longitudinal axis of the intake duct is arranged. 2. Device according to claim 1, characterized records that the additional gas is additional air. 3. Device according to claim 1, characterized characterized in that the additional gas exhaust gas of the Internal combustion engine is.   4. The device according to claim 1, characterized characterized in that the additional gas is a catalytic fission gas obtained from exhaust gas.