EP0118500B1 - Method and device for dissolving a gas, particularly carbon dioxide, in a liquid fuel, and dispensing it in saturated conditions into combustion air - Google Patents

Abstract

The process and the device are intended to dissolve a gas, particularly carbon dioxide or compressed air, in a liquid fuel with pressure and temperature conditions such that upon introducing the saturated solution in the combustion air, the solution is finally and homogeneously dispersed. The fuel is introduced into a mixer (11) by means of a pump (41), the gas is supplied by means of a doser (29). The mixer (11) comprises a swirling chamber (163), a mixing dome (161) and an exhaust pipe (164) which supplies with a bubble-free solution the carburator or injector of a combustion engine or of a combustion chamber. The doser (29) operates as a function of the fuel consumption and of the gas quantity measured in the mixing dome (161) by a manometer (46) or a photosensor (51).

Description

The invention relates to a method for distributing liquid fuel in combustion air, to which the fuel is mixed via a carburetor or injector, in which gas, preferably air and / or carbon dioxide, is present in the fuel at such a solution pressure-temperature state, in which a higher Solubility of the gas as given under the mixed pressure-temperature state of the combustion air during the admixture is dissolved in such a quantity ratio that the saturation quantity ratio in the mixed-pressure temperature state is exceeded, and this solution is fed to the gasifier or injector.

It is known that liquids in which gases are dissolved spontaneously release the dissolved gas in the event of a sudden drop in ambient pressure or a rapid temperature increase in which the state of supersaturation occurs due to the lower solubility of the gases at lower pressure or higher temperature and lather up or, in the case of simultaneous spraying, break up into fine droplets.

Patent specification DE-C 471 423 describes a compressor system in which the combustion air and the liquid fuel are brought together under pressure, then compressed further and then fed to an atomizing nozzle. Here, part of the combustion air is dissolved by the compression in the fuel, and the solution is fed together with the remaining air as a mixture to the nozzle. However, this mixture of air bubbles and solution cannot be atomized evenly.

Furthermore, it is known from FR-A 1 177 722 to dissolve gas in liquid fuel at normal pressure in a large tank by means of an agitator and then to burn the solution dropwise at normal pressure. Since the pressure conditions during dissolving and burning are the same and the solution is only added to the furnace drop by drop, there is only an uneven distribution of the fuel in the burner zone.

Furthermore, it is known from FR-A 2249954 to supply a liquid fuel together with steam or gas via a turbulence zone in a feed line to an injector under pressure in order to reduce the viscosity of the fuel. With this arrangement, the excess gas or vapor emerges in bubble form with the liquid from the nozzle and disrupts uniformly fine atomization.

On the other hand, it is known to distribute liquid fuels in combustion air by spraying and partial evaporation by heating and swirling. These mixing measures all intervene behind the so-called carburetor or the injector nozzles or burner nozzles, by aiming for a uniform and intensive mixing through vortex zones and special design and location of the combustion or explosion space for supplying the fuel or the fuel-air mixture. However, all of these measures are not sufficient to achieve a completely uniform and very fine fuel distribution, which is why either part of the fuel leaves the combustion chamber unburned or split as carbon monoxide or carbon, or if an excess of air is supplied it is uselessly used to form nitrogen oxides and harmful exhaust gas is released.

It is an object of the invention to disclose a method and a device by means of which the distribution of fuel in combustion air takes place much more evenly and finely, so that the disadvantages of the known methods are reduced and better combustion with higher efficiency, less harmful exhaust gases, more reliable Ignition and thus less starting difficulties with engines and less knock tendency with engines can be achieved.

The solution to the problem is given by the fact that the fuel is completely saturated with the gas in the solution pressure temperature state, the fuel and the gas are continuously fed, metered according to the solvency, to a gas-liquid mixer and from this the solution that forms and a gas bubble stream over a vortex section, largely dissolving, is led to an overlying mixing dome and that from there the saturated solution is discharged via a discharge section at a sinking rate that is lower than the rate of rise of gas bubbles and then fed to the gasifier or injector.

The method can be used for both explosive and continuous combustion systems. Depending on the application, different gas-fuel solutions can be used particularly advantageously.

When used in conjunction with vacuum gasifiers, it is advantageous to use a gas with high solubility, e.g. Carbon dioxide in which to dissolve gasoline.

Furthermore, when burning difficultly flammable liquids, e.g. Diesel oil or heavy oil, particularly advantageous as an ignition aid, to use hydrogen.

When burning fuels with a relatively high carbon content, e.g. Benzene is advantageous to the solution of oxygen.

The least technical effort is required when using compressed air, which is generated on site by a relatively small compressor. A sufficient amount of air for the intended purpose is released especially when the fuel is saturated under a pressure of several atmospheres.

Switching or mixing operation with different gases, for example carbon dioxide, at the start or at low temperature and air for the ongoing operation results in an advantageous combination regarding the technical effect and economy of the use of materials. The use of carbon dioxide can also be increased relatively under difficult operating conditions in which there is a tendency to knock.

The device for dissolving the gas is a closed unit that can be easily inserted into the fuel line. In an advantageous embodiment, the device is controlled on the basis of internally obtained criteria of the fuel flow and the saturation achieved.

With a strongly changing flow, e.g. in engines, the control criterion for the fuel metering is used to control the device for saturation.

• Fig. 1 zeigt eine schematische Darstellung von einer Vorrichtung zur Lösung von Gasen im Brennstoff;
• Fig. 2 zeigt einen alternativen Mischer zur Anlage Fig. 1;
• Fig. 3 zeigt einen weiteren Mischer zur Anlage Fig. 1;
• Fig.4 zeigt den Anschluss der Vorrichtung nach Fig. 1 an einen Dieselmotor;
• Fig.5 zeigt den Anschluss der Vorrichtung nach Fig. 1 an einen Einspritzermotor;
• Fig. 6 zeigt den Anschluss der Vorrichtung nach Fig. 1 an einen Heizungsbrenner;
• Fig.7 zeigt den Anschluss der Vorrichtung nach Fig. 1 an ein Strahltriebwerk.

A device for carrying out the method and the insertion in known internal combustion engines and systems is shown in FIGS. 1 to 7.

• Fig. 1 shows a schematic representation of a device for dissolving gases in the fuel;
• Fig. 2 shows an alternative mixer to the system of Fig. 1;
• Fig. 3 shows a further mixer for the plant of Fig. 1;
• 4 shows the connection of the device according to FIG. 1 to a diesel engine;
• 5 shows the connection of the device according to FIG. 1 to an injector engine;
• FIG. 6 shows the connection of the device according to FIG. 1 to a heating burner;
• 7 shows the connection of the device according to FIG. 1 to a jet engine.

The device for dissolving gases in fuels, which is shown in FIG. 1, consists of an injector mixer 11, the nozzle 12 of which is fed via line 13 to the fuel. The nozzle 12 is surrounded by a mixing chamber 311, into which the gas, here compressed air or carbon dioxide, is fed via line 31. Connected to the mixer 11 is a vertical cylindrical tube 15, in which the gas bubbles dissolve in the fuel in a swirl section 163. The pipe 15 is expediently dimensioned such that the height h of the swirl section 163 corresponds approximately to twice the diameter d and, at maximum fuel throughput, the gas bubbles have practically completely dissolved when the upper region is reached. Undissolved gas collects in the mixing dome 161 above the upper end of the tube 15. A housing 16 extends downward from the mixing dome 161 concentrically to the tube 15, the diameter of which is selected such that in the discharge path 164 between the housing 16 and the tube 15 the sink rate of the fuel at maximum throughput is less than the rate of rise of any remaining gas bubbles. At the lower end of the housing 16, the fuel line 17 is connected, which leads to the so-called carburetor or the injection devices.

For optimal control of the correct metering of the amount of gas added, the housing 16 is made of glass or at least partially of glass.

The fuel is conveyed from the tank 40 with the pump 41 via a filter 42 in a known manner and under pressure through a fuel line 17.

Between the connection 171a, to which connection 171d (FIGS. 4 to 7) connects in known engines and combustion systems, the device with connection 171b and 171c is inserted, a check valve 44 being expediently installed in the lines 17 and 13, so that the Pressure in the housing 16 is always maintained in order to maintain the saturation of the fuel.

The carbon dioxide is fed from a pressure bottle 20 via a reducing valve 21 to a mixing line 26, and on the other hand, compressed air is filled with the compressor 23 into a storage container 22 and also fed to the mixing line 26 via a reducing valve 25. Such a compressed air system is e.g. for trucks, already available. Because of the relatively low air requirement, it is sufficient for a passenger car to load a storage container each time with a compressor; or a small separate compressor can be provided.

A manometer 27 is used to monitor the pressure in the mixing line 26. The valve 28 opens the mixing line 26 to the metering device 29 by means of an operating signal, from which line 31 leads to the mixer 11 via the check valve 30. Depending on the design of the components mentioned, their functions can also be carried out integrated in special components. Thus, when the metering device 29 is firmly closed in the inoperative state, a separate valve 28 can be omitted. Furthermore, the storage container 22 can be omitted if a special compressor 23, which is always running, is provided. If this is controllable, it can also take over the function of the dosing device 29.

If a constant fuel flow, e.g. with heating burners, the dosage can be set once, e.g. based on the observed bubble resolution before reaching the mixing dome 161. The observation can also be carried out by a pressure meter 46 or a gas bubble sensor, e.g. a floating body or, as shown, a light barrier 50, 51, which also offers the possibility of automatically regulating the dosage. For this purpose, the signal line 461 or 511 is fed to a control device R and its signal is compared with a predetermined value, which corresponds to the presence of a low bubble flow compared to the bubble flow at the outlet of the mixer 11, and the metering device 29 is controlled by the difference signal via line 291.

In the case of strongly fluctuating fuel consumption, it is advantageous to provide a return line 47 from the mixing dome 161 via a further metering device 45 to the tank 40. This metering device 45 is opened when a gas bubble that is large in relation to normal operation has collected in the mixing dome 161, which is done automatically by means of a comparison of the signal of the light barrier 50, 51 with a correspondingly high comparison value via line 451.

The control of the gas volume flow, depending on the fuel throughput, can also be carried out by specifying a metering signal on the input lines 60b, 64b of the control device R, to which the said difference signal of the control deviation is additionally added, if control is additionally provided.

Since it takes a certain amount of time for the gas bubbles to pass through the vortex section 163, it is necessary to provide an adapted delay in the control device for the control signals in order to avoid control vibrations.

If there is a very large fuel requirement, it is expedient for reasons of overall height to accommodate several mixers 11 with tubes 15 in parallel in a housing 16 or to provide other mixers instead of the injector nozzle 12.

2 shows an alternative embodiment of the mixer 11, which is equipped with a sintered candle 314, through the pores of which the gas enters the mixing chamber 312 in fine bubbles. The sintered body could also be provided flat on the bottom of the tube 15, through which the fuel enters laterally.

3 shows a further alternative embodiment of the mixer 112, which consists of a known static mixer, the mixing chamber 313 of which the gas and the fuel are supplied.

The choice between the different mixers 11, 111, 112 is expediently made in accordance with the pairing of the selected gas and the fuel and their properties, in particular with regard to soiling or clogging of the pores or nozzle. Furthermore, the mixability is a selection criterion in the event of very different throughputs.

The connections of the devices according to FIGS. 2 and 3 are designated in accordance with those in FIG. 1.

The gas is generally dissolved at a pressure starting approximately from two atmospheres, higher pressures being preferred. If, however, a so-called carburetor of a carburetor engine is connected downstream of the device, which cannot be under excess pressure, a readily soluble gas, e.g. Carbon dioxide. Both the negative pressure during the so-called gasification process then creates the supersaturation state, which causes a finer distribution of the fuel, and when the mixture of fuel and air is subsequently heated by the heating through the cylinder wall, a further release of gas and thus splitting of the droplets occurs .

4 shows how the device is inserted into a diesel engine 63. The solution of diesel oil and air or carbon dioxide saturated at approximately 10 atmospheres is fed to the injection pump 60, from where it reaches the combustion chamber 62 through the injection nozzle 61.

Since the compressed air, which may also be heated by the cylinder walls, has a high temperature, the solubility of the gas is exceeded despite the high pressure, and the solution is finely atomized by the escaping gas. As a result, the cold start property in particular is significantly improved, and saturation with the readily soluble carbon dioxide is therefore recommended at the start. When the engine is warm, saturation with air is sufficient to improve efficiency and reduce harmful emissions and soot formation.

Depending on the engine temperature, valves 21 and 25 for carbon dioxide and compressed air are expediently reversed.

For metering the gas flow, i.e. the control of the metering device 29 is fed directly via a signal line 60b from the metering control line 60a to the injection pump 60, a control signal from the control device R or the metering device 29.

An injection engine 67 is shown in FIG. 5, the fuel flow divider 64 of which supplies the saturated solution, from which it is directed to the injection nozzle 65. Since the combustion air drawn in at the same time has a considerably lower pressure than the solution, the solution is spontaneously atomized by the released gas, which improves both the combustion and the cold start properties. The mixture ratio of fuel and combustion air can therefore be set to an even lower air excess than in known engines of this type, which leads to a further increase in efficiency and a reduction in pollutant emissions. If carbon dioxide is dissolved in the fuel, the knock resistance of the solution is increased compared to the pure fuel. This is an additional beneficial effect. The control signal for the metering device 29 occurs through the control signal of the fuel quantity divider; which is taken from line 64a via line 64b.

6 shows a heating burner, in the fuel line of which the device for dissolving gas is arranged upstream of the controlled valve 70. As soon as the pressurized solution enters the combustion air from the burner nozzle 71, the fuel is finely divided by the released gas and mixed with the air flow. This effect is intensified by the retroreflection from the flame zone 73 into the mixing zone 731, since the heating releases further gas which separates the droplets again.

Since the flame through the fine distribution of the Fuel burns practically soot-free, there is no soot deposition on the downstream heat exchanger, which further improves the efficiency of the heating system compared to known heating systems.

The process is well suited for both heating oil and heavy oil as well as for a fuel-pollutant mixture. To further improve the ignitability of the solution, a flammable gas, e.g. Hydrogen, natural gas or propane gas can be dissolved in the fuel.

Since the fuel flow is constant, the metering of the amount of gas is fixed, which leads to a very simple device.

FIG. 1 shows a jet engine 83, in the fuel feed line of which the device for dissolving gas is inserted. Since the supply pressure of the nozzles 81 is relatively high, a large amount of gas can be dissolved in the fuel and a substantial improvement in the distribution of the fuel can be achieved during the residence time in the mixing zone 81. The radiant heat that comes from the flame zone 82 into the mixing zone 81 also contributes to this, which causes the fuel droplets to be divided again by the release of gas. A practically soot-free combustion and an increase in efficiency is achieved.

Carbon dioxide is particularly suitable for saturating the fuel because of its high solubility, and also a combustible gas because of its good ignitability, which largely prevents engine exposure.

In this arrangement, too, a control signal is fed from the fuel metering device to the control device R for metering the gas flow. When using flammable gases or gases with a high oxygen content, the known safety engineering measures must be taken into account. In these cases, the swirl section 163 is expediently dimensioned so large that there is no removal of gas via a metering device 45.

The optimal configuration of the arrangements according to the invention in the shown and other similar applications can be achieved by a suitable combination of the details shown or also by an expert selection of suitable combinations of fuel and gas. The devices shown for dissolving gas in the fuel can be replaced by other equivalents, provided they provide solutions that meet the requirements of the method.

The signals for controlling the metering of the gas flow and the corresponding control device can be configured electronically, mechanically, pneumatically, etc., depending on the metering devices for the fuel. Thus, the time pulses that serve to control the injection are also expediently used to control the metering device when using an electromagnetically controllable valve. In another embodiment with an injection pump adjustment by rotating a shaft, this rotation acts directly or via a cam on a mechanically acting metering device. According to a further embodiment, the rotation is detected by a sensor, e.g. a potentiometer, converted into an electrical signal and fed to an electronic control device.

Claims (15)

1. Method of distributing liquid fuel in combustion air that the fuel is admixed through a carburetor or injector by which method prior to the admixture a gas preferably air and/or carbon dioxide is dissolved in the fuel, at a state of solution pressure and temperature at which a higher gas solubility of the gas is ensured than at the state of mixing pressure and temperature of the combustion air during admixture, in a quantitative ratio such that the saturation-quantity ratio is exceeded at the state of mixing pressure and temperature of the combustion air and the solution supplied to the carburator or injector, characterized in that the fuel is completely saturated with the gas at the state of the solution pressure and temperature and the fuel and the gas are continuously supplied regulated in a ratio corresponding to solubility into a gas to fuel mixer (11, 111, 112) from which the evolving solution and a gas bubble stream through a turbulent section (163), whereby the stream of gas bubbles is extensively dissolved, is supplied to a mixing dome (161) which is located above of the mixer (11, 111, 112) hence the solution is diverted into an exhaust section (164) wherein the saturated solution is directed downwardly with such a sinking speed that is lower than the speed at which the gas bubbles rise whereafter the saturated solution is fed to the carburetor respectively the injector (61, 65, 71,81 ).

2. Method as in Claim 1, characterized in that the dissolution pressure is several atmospheres above the mixing pressure of the combustion air and the solution temperature and mixing temperature are approximately equal or the mixing temperature is higher than the solution temperature.

3. Method as in Claim 1, characterized in that the solution temperature equals the ambient temperature and the mixing temperature is higher due to the addition of combustion heat in the form of radiation from the combustion zone or from the walls of the combustion chamber and the dissolution pressure and mixing pressure are approximately equal to normal pressure or the mixing pressure is lower than normal pressure.

4. Method as in one of Claims 1 through 3, characterized in that the gas dissolves readily (carbon dioxide), burns readily (hydrogen), and/ or is oxidizing (oxygen).

5. Method as in one of Claims 1 through 4, characterized in that the fuel is methyl alcohol, ethyl alcohol, gasoline, benzene, heating oil, diesel oil, heavy oil, or a mixture of fuel and pollutant.

6. Device for carrying out a method as in one of Claims 1 through 5, characterized in that the mixer (11) is an injector-mixer to which the fuel is supplied through a vertical nozzle (12) and the gas is supplied to a mixing chamber (311) that encloses the nozzle (12), or a sintered-candle mixer (111) in which the gas is supplied to one side of a sintered, porous intermediate layer inside a cylindrical sintered body (314) and the fuel is applied to the mixing chamber (312) on the other side of the intermediate layer, or a static mixer (112) with the gas and fuel being supplied to its mixing chamber (313) and that a preferably cylindrical pipe (15) containing the turbulent section (163) is positioned downstream of the mixer (11,111,112) and the pipe (15) has a height (h) that is higher, e.g. twice, its diameter (d) and in that a cylindrical housing (16) is positioned concentric to the pipe (15) in the form of an exhaust section (164) with a fuel-exhaust line (17) connected to its lower section (162).

7. Device as in Claim 6, characterized in that several mixers (11, 111, 112) and pipes (15) are accommodated one next to another in one housing.

8. Device as in one of Claims 6 or 7, characterized in that the fuel is supplied from a tank (40) to the mixer (11, 111, 112) through a filter (42) and a check valve (44), whereby a pump (41) supplies the dissolution pressure.

9. Device as in one of Claims 6 through 8, characterized in that the gas is supplied from a pressure tank (20) through a reduction valve (21), or from a compressor (23) through a check valve (24) and a reduction valve (25) and further it is fed to the mixer (11, 111, 112) through a flow regulator (29).

10. Device as in claim 9, characterized in that the flow regulator (29) is connected to a regulator (R) that is connected on the input side with a pressure gauge (46) or gas-bubble sensor, e.g. a float or a light sensor (51) of a light barrier (50, 51), that signals the intensity of the stream of gas bubbles in a mixing dome (161) above of the turbulent section (163) and the regulation device (R) controls the flow regulator (29) in such a way that the signal from the light barrier (50, 51) is compared with a reference value that equals the signal from a given stream of gas bubbles that is relatively low as compared to the stream of gas bubbles at the exit from the mixer (11) and the resulting differential signal functions as a control parameter.

11. Device as in Claim 9 or 10, characterized in that a fuel-return line (47) leading to a tank (40) is positioned at the mixing dome (161) with a flow regulator (45) that is turned on by the control device (R) when the gas-bubble sensor signals the presence of a large gas bubble in the section (161) by means of an appropriately relatively high output signal.

12. Application of the method as in one of Claims 1 through 5, whereby gas is dissolved in the fuel in the section (171 a-171 d) of the fuel line (17) between the pump (41) and

the fuel-flow divider (64) in the case of an injection engine, or

the injector pump (60) in the case of a diesel engine,

characterized in that the fuel is completely saturated with the gas at the state of the solution pressure and temperature and the fuel and the gas are continuously supplied regulated in a ratio corresponding to solubility into a gas to fuel mixer (11, 111, 112) from which the evolving solution and a gas bubble stream through a turbulent section (163), whereby the stream of gas bubbles is extensively dissolved, is supplied to a mixing dome (161) which is located above of the mixer (11, 111, 112) hence the solution is diverted into an exhaust section (164) wherein the saturated solution is directed downwardly with such a sinking speed that is lower than the speed at which the gas bubbles rise whereafter the saturated solution is fed to the carburetor respectively the injector (61, 65, 71, 81), whereby the solution pressure is equal or higher than the mixing pressure and the solution temperature is lower than the mixing temperature.

13. Application of the method as in Claim 12, characterized in that the control parameters (60a, 64a) supplied to the fuel-flow regulation devices like the injector pump (60) or fuel-flow divider (64) are supplied as control parameters (60b, 64b) or regulating control parameter to the gas to fuel flow regulator (29).

14. Application of the method as in one of the Claims 1 through 5, whereby in a heating and combustion device gas is dissolved in the fuel in a section (171a-171d) of a fuel line (17) between a pump (41) and a burner nozzle (71), characterized in that the fuel is completely saturated with the gas at the state of the solution pressure and temperature and the fuel and the gas are continuously supplied regulated in a ratio corresponding to solubility into a gas to fuel mixer (11, 111, 112) from which the evolving solution and a gas bubble stream through a turbulent section (163), whereby the stream of gas bubbles is extensively dissolved, is supplied to a mixing dome (161) which is located above of the mixer (11, 111, 112) hence the solution is diverted into an exhaust section (164) wherein the saturated solution is directed downwardly with such a sinking speed that is lower than the speed at which the gas bubbles rise whereafter the saturated solution is fed to the carburetor respectively the injector (61, 65, 71, 81), whereby the solution pressure is higher than the mixing pressure and the mixing temperature is higher than the solution temperature.

15. Application of the method as in one of the Claims 1 through 5, whereby in a reaction engine gas is dissolved in the fuel in a section (171a-171d)of afuel line(17) between a pump (41) and a reaction nozzle (81), characterized in that the fuel is completely saturated with the gas at the state of the solution pressure and temperature and the fuel and the gas are continuously supplied regulated in a ratio corresponding to solubility into a gas to fuel mixer (11, 111, 112) from which the evolving solution and a gas bubble stream through a turbulent section (163), whereby the stream of gas bubbles is extensively dissolved, is supplied to a mixing dome (161) which is located above of the mixer (11, 111, 112) hence the solution is diverted into an exhaust section (164) wherein the saturated solution is directed downwardly with such a sinking speed that is lower than the speed at which the gas bubbles rise whereafter the saturated solution is fed to the carburetor respectively the injector (61, 65, 71, 81), whereby the solution temperature is equal to the ambient temperature and the mixing temperature is higher than the solution temperature due to addition of radiation heat from the combustion zone and whereby the solution pressure is equal to the mixing pressure.

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