CH683938A5 - Preparing lean air=fuel mixt. for four stroke IC engine - providing mixt. of variable composition by supplying liq. fuel to vaporiser in mixing chamber with air inlet and mixt. outlet coupled to intake of engine - Google Patents

Abstract

The liq. fuel is metered to the vaporiser (1) via a dosing valve (27). The composition of the mixt. is matched to the engine power demanded by means of this valve and a regulating flap (28). The preparation and transport of the mixt. to the intake follows by ambient pressure. A microprocessor unit receives, as well as a signal corresp. to the desired engine power, signals from sensors assigned to the i.c. engine corresp. at least to the r.p.m., intake pressure and cooling water temp. On the other hand, it receives further signals via sensors corresp. at least to the prevailing ambient pressure and temp. In combination with a data memory unit, the microprocessor unit continuously delivers control signals for regulating the dosing valve and adjusting motor for the regulating flap and engine regulation according to the characteristic field of the engine. USE/ADVANTAGE - Optimum drive with lean mixt. at lambda values between 1.4 and 1.8 to 2 or higher. Provides extremely fine spray with drops of 20 microns at most and evenly distributes for homogeneous ignition level.

Description

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The invention relates to a method for the mixture preparation and the supply of gasoline engines with lean fuel-air mixtures of variable composition, liquid fuel being supplied to an atomizer in a mixing chamber with an air inlet and a mixture outlet connected to the intake line of the gasoline engine.

Motor vehicles with a petrol engine are now equipped as standard with the well-known regulated three-way catalytic converter in order to comply with the legal regulations with regard to the permissible pollutant limit values.

As part of the ongoing discussions about measures to reduce pollutant emissions, the so-called lean concept is also mentioned. The operation of gasoline engines with lean fuel mixtures with a significant excess of air according to the lean concept offers the possibility to reduce pollutant emissions and at the same time to reduce fuel consumption. This could eliminate the need for a three-way catalytic converter and optimize the petrol engine's consumption.

The interest in the development of so-called lean-burn engines or lean-burn mixed engines i.e. Gasoline engines that work with stoichiometric air-fuel ratios (lambda values much larger than 1) are clearly evident from numerous publications. An article by G. Lech and V. Harms in the journal "Motortechnische Zeitschrift", 47 (1986) 10, pp. 423-427 concerns the problems of lean-burn combustion with changing air conditions (lambda values) up to 1.7.

However, the requirements for vehicle operation with lean engines are particularly strict and sometimes contradictory.

Various devices for the preparation of fuel-air mixtures have been proposed and in this connection the following patents and published patent applications are mentioned, for example: US 4,353,848, US 4,469,075, GB 1,588,856, DE 2 809 066 A1, DE 3,024,181 A1, WO 84/03735 A1, WO 83/04282 A1, WO 85/00412, CH 663 823, CH 606 784, EP 0 209 073 A2 and EP 0 208 802 A1.

It has been shown that for perfect combustion in lean-burn engines, the liquid fuel must be atomized into extremely fine drops of at most 20 microns and distributed very evenly in order to achieve homogeneous ignitable fuel-air mixtures.

However, the fulfillment of the mentioned conditions for perfect combustion by extensive atomization and uniform droplet distribution is particularly problematic in the case of variable operating conditions in that the required mixture composition cannot be guaranteed in the case of transient operating states if uncontrolled amounts of fuel are carried in the mixture. Therefore, on the one hand, the perfect fuel control with changing air volumes and, on the other hand, the use of the simplest possible technical means are of critical importance for the trouble-free continuous operation of motor vehicles.

The invention has for its object to provide a method of the type mentioned, which can be carried out with the simplest and most reliable technical means and largely takes into account the problems mentioned above and the satisfactory mixture preparation and the supply of gasoline engines with lean fuel air Mixes of variable composition in the entire operating range of the gasoline engine.

This object is achieved with the method of the type mentioned at the outset with the features defined in claim 1.

In the method according to the invention for supplying gasoline engines with lean mixtures of variable composition, the mixture formation takes place essentially at ambient pressure, the mixing chamber with the atomizer limiting an aerodynamically favorable flow path between the air inlet and the mixture outlet and being equipped with a control flap which is operatively connected to a Fuel metering valve is regulated in a predetermined, preferred operating range in which the gasoline engine works with lean mixtures of variable composition.

In addition, according to the invention, metered amounts of fuel are fed to the atomizer via the fuel metering valve and are adapted to the engine power required in such a way that the gasoline engine can be operated in the operating range mentioned.

In conjunction with the metering valve, the composition of the mixture is continuously adjusted to the required output at the corresponding operating point with the help of the control flap so that the mixture formation and the transport of the mixture in the intake line of the gasoline engine can take place approximately at ambient pressure.

The range for the operation of the gasoline engine with lean mixtures of variable composition and the highest possible excess air can preferably be delimited in advance by gradually scanning the operating range of the gasoline engine at different speeds and loads, each with the fuel consumption, the mixture and exhaust gas The composition and the intake pressure are determined, the control flap is adjusted and an engine map is set up, which determines the optimal position of the control flap at the corresponding operating points, so that when operating with the highest possible excess air in the operating range of the gasoline engine, the mixture preparation and supply of the gasoline engine essentially at ambient pressure takes place, fuel consumption is reduced and pollutant emissions can be reduced.

This process is preferably used to prepare mixtures with an excess air number which is at least 1.4.

The amount of air sucked in by the internal combustion engine, on the other hand, can either be direct, at 5

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for example with the help of a hot wire anemometer, or indirectly via the measured intake pressure, the temperature and the engine speed.

The atomization of the liquid fuel is advantageously carried out independently of the amount of air using a rotating atomizer with a motor drive.

The invention further relates to a mixture formation device for carrying out the method according to claim 1, which has the combination of features defined in claim 6.

The device for carrying out the method according to the invention is essentially equipped with an atomizer, which consists of a cup with a central hollow nozzle, a distribution plate and a rising cylinder with an upper spray edge, is mounted on a drive shaft and is connected to a drive motor.

Furthermore, a central prechamber is provided in the hollow connector, which is open at one end, has a bottom at the other end and is connected to the upper distribution surface of the distribution plate. In addition, a fixed fuel supply pipe is equipped with a regulated fuel metering valve, with its free end projecting axially into the prechamber without contact and its fixed outlet opening being centrally located at an axial distance from the bottom of the prechamber so that the fuel flows out this opening can emerge unhindered. Furthermore, a control flap with a servomotor is provided, so that in connection with the fuel metering valve, with the help of this control flap, the composition of the mixture can be continuously adapted to a required output at a corresponding operating point in such a way that the mixture formation and the transport of the mixture in the intake line can take place approximately at ambient pressure.

This mixture formation device has a relatively simple structure and essentially comprises a fuel metering valve in an inflow pipe, a rotationally symmetrical atomizer with a drive motor and a drive shaft, and a control flap with a servomotor.

Thanks to the arrangement provided according to the invention and the interaction of the exposed central outlet of the inflow pipe with the bottom of the prechamber in the hollow socket of the rotating atomizer, the liquid fuel can be regulated precisely to the desired flow rate by the metering valve in the inflow pipe and then escape freely or by centrifugal force from Atomizers are continuously removed and atomized.

Due to this special arrangement and mode of operation, the control of the fuel quantity takes place independently of the atomization, whereby these functions continuously follow each other immediately and can be achieved with very simple means.

This makes it possible to regulate the amount of fuel in the resulting mixture independently of the amount of air and, in conjunction with the metering valve with the help of the control flap, to precisely adjust and vary the mixture composition as required or to adjust it to the required output so that the mixture formation and the mixture can be transported in the suction line approximately at ambient pressure.

A fixed covering is preferably provided for the holder of the atomizer cup so that it forms an annular channel with the wall of the mixing chamber between the air inlet and the mixture outlet.

The wall of the mixing chamber is advantageously provided with a heating jacket so that impinging fuel drops evaporate.

Furthermore, the control flap is advantageously arranged in the region of the mixture outlet of the mixing chamber.

The free end of the drive shaft can preferably be mounted in the hollow socket, it having an axial blind hole which forms the central prechamber with the base mentioned.

In a preferred embodiment, the drive shaft forms an annular intermediate chamber with the hollow connector, which is connected to the central prechamber via a first radial bore and to the said distribution plate via a second radial bore, these bores being diametrically opposite one another.

The drive motor can be arranged below the atomizer cup and with it within the casing, the spray edge standing free and spraying the fuel radially, so that it mixes with the intake air in the ring channel mentioned.

In this arrangement, the atomizer cup is preferably covered by a hood, which widens from the air inlet of the mixing chamber in the direction of the spray edge, so that the sucked-in air is supplied to the ring channel unhindered.

The outlet of the mixing chamber is preferably adapted to the connection to the intake line of the gasoline engine, so that the fuel mixture can be transported to the gasoline engine with insignificant pressure loss.

The mixture formation device preferably has a data processing unit with a microprocessor unit which, in conjunction with a data storage unit, depending on the power demanded by the gasoline engine and the engine speed, simultaneously the fuel metering valve and the servomotor of the control flap of the mixture formation device and the ignition of the gasoline engine according to a stored program regulates that corresponds to a map in a previously defined operating range of the gasoline engine.

In addition to a signal corresponding to the power required by the gasoline engine, the microprocessor unit receives input signals on the one hand via corresponding sensors on the gasoline engine, which at least correspond to the engine speed, the intake pressure and the cooling water temperature of the gasoline engine, while on the other hand it receives additional input signals from the environment which correspond at least to the ambient pressure and the ambient temperature.

Furthermore, this microprocessor unit in connection with the data storage unit is dependent5

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speed of these input signals, according to the characteristic map in the previously defined operating range of the gasoline engine, continuously corresponding control signals for the control of the fuel metering valve, the servomotor of the control flap and the ignition of the gasoline engine.

In the limited operating range of the gasoline engine, the characteristic map defines the setting of the control flap, the metering valve and the engine ignition by means of predetermined values of the corresponding control signals for each operating point, so that the gasoline engine in the entire operating range with variable composition and maximum air excess while reducing fuel consumption and of pollutant emissions can be operated optimally.

The invention is explained in more detail with reference to preferred exemplary embodiments of a mixture formation device and a control system for carrying out the method according to the invention, which are shown schematically in the accompanying drawing as follows.

Fig. 1 shows schematically a partial longitudinal section through a mixture formation device according to an embodiment.

Fig. 2 shows schematically the arrangement of a mixture formation device on an internal combustion engine.

3 schematically shows a control system for the operation of a lean-burn engine with the mixture formation device.

Fig. 1 shows the atomizer cup 1, which is mounted on the drive shaft 5 of an electric drive motor 6, carried with it in an approximately spherical casing 20 and is arranged axially within a mixing chamber 21.

The mixing chamber 21 has an air inlet 24, a mixture outlet 25, a control flap 28 with a servomotor 29 and a curved, rotationally symmetrical wall 22 which is adapted to the casing 20, forms a streamlined annular channel 23 with it and is provided with a schematically indicated heating jacket 26 .

A fixed fuel supply pipe 10 in operative connection with a metering valve 27 extends axially through the air inlet 24 into the atomizer cup 1. The outlet opening 11 of the inflow pipe 10 is provided with a check valve, not shown, which closes at ambient pressure when the fuel flow is interrupted.

A conical hood 30 covers the open top of the cup 1 at a short distance above the spray edge 16 of the cup 1.

The air inlet 24 of the mixing chamber 21 is normally connected to an air filter (not shown), the mixture outlet 25 being connected here to the schematically indicated intake line 31 of a gasoline engine in order to supply it with lean fuel mixtures.

As can also be seen from FIG. 1, the wall 22 of the mixing chamber 21 and the cladding 20 are curved and matched to one another, so that the annular channel 23 has a streamlined or aerodynamically favorable flow path between the rounded air inlet 24 around the hood 30 and the cladding 20 around to the mixture outlet 25 results.

The rotating atomizer consists of a cup 1 open at the top with a central hollow connector 2, an annular distribution plate 3 and a riser cylinder 4 and is mounted on the drive shaft 5 of the motor 6.

The hollow connector 2 encloses the free lower end of the drive shaft 5, which has an axial blind hole and thus forms a central prechamber 7, which is open at the upper end and has a bottom 8 at the lower end of the blind hole.

The inflow pipe 10 projects axially into this prechamber 8 without contact, its fixed central outlet opening 11 being at a sufficiently large axial distance from the bottom 8 of the prechamber 7 so that the liquid fuel can escape axially from this opening 11 in any desired controlled quantity .

An inner annular groove is also provided in the hollow connector 2 so that it forms an annular intermediate chamber 12 with the tubular end of the drive shaft 5, which is connected to the prechamber 7 via the radial bore 13 in the region of the base 8.

The distribution plate 3 of the atomizer cup 1 has an annular distribution surface 14 which extends to the foot of the rising cylinder 4, which has an upwardly increasing inner rising surface 15.

The upper end of the riser surface 15 is also connected via a radially inwardly projecting overflow edge 16 and a subsequent rounded end surface 17 with a spray edge 18 on the outside of the riser cylinder 4 so that the rising liquid suddenly directed radially inward at the overflow edge 16 and is then gradually fed radially outward over the end face 17 of the spray edge 18.

The intermediate chamber 12 is connected to the distribution surface 14 via a second radial bore 19 in the hollow connector 2, the bores 13 and 19 being arranged diametrically opposite one another.

When the device is in operation, the drive motor 6 rotates at a high speed of, for example, 10,000 revolutions per minute, and the liquid fuel is fed through the metering valve 27 and the inflow pipe 10 to the central outlet opening 11 in a precisely controlled amount, flows freely from this opening 11 into the antechamber 7 into where it is deflected radially outwards at the bottom 8 and is fed to the upper distribution surface 14 of the plate 3 by centrifugal force via the small radial bore 13, the intermediate chamber 12 and the radial bore 19.

As a result, a liquid film is formed which radially spreads out on the distribution surface 14 with decreasing film thickness, rises on the conical inner rising surface 15, is deflected inwards via the overflow edge 16 and via the end surface 17

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reaches the upper spray edge 16, where the fuel film is divided and sprayed radially in the form of extremely fine drops.

The atomizer 1 is thus designed in such a way that the fuel which escapes from the fixed central opening 11 is distributed successively by centrifugal force in the prechamber 7, in the intermediate chamber 12, on the distribution surface 14 and the rising surface 15, in the form of a uniform liquid film of very small, practically constant thickness is supplied to the overflow edge 16, overflows at it and is divided into extremely small (for example 20 microns) drops at the spray edge 18 and is radially sprayed and intimately mixed with the air flow in the annular channel 23.

With this arrangement of the atomizer cup 1, the amount of fuel regulated via the metering valve 27 and emerging from the opening 11 is continuously removed from the central prechamber 7 by centrifugal force, repeatedly distributed, evenly spread and fed to the inner overflow edge 16 as an extremely thin liquid film on the end face 17 and the spray edge 18 is completely divided and sprayed radially.

This special arrangement and mode of operation of the atomizer cup 1 results in a uniform film formation and atomization, whereby any discontinuities in the liquid film are compensated for, which occur in particular as a result of transient effects when the operating state or the liquid supply changes, and can more or less impair the atomization.

The amount of liquid fuel in the resulting mixture is regulated independently of the amount of air sucked in only by the fuel metering valve 27.

2 schematically shows an arrangement of the mixture formation device MFD according to the invention on a lean-burn engine LE with four cylinders C1, C3, C2, C4, which are shown in their firing order.

The fuel mixture is continuously formed from the air A drawn in by the engine LE and the fuel F and distributed in the cylinders C1-C4 via the intake line IM of the lean-burn engine LE, the ignition being controlled by an ignition control signal IC.

According to the invention, this device MFD is equipped, as described, with a metering valve and a control flap and forms a regulated mixture generator which can precisely regulate the flow rate and the composition of the mixture and can optimally adapt to all required operating states of the lean-burn engine LE without additional aids.

3 shows a control system with a mixture forming device MFD for supplying a gasoline engine LE with lean fuel mixtures according to the invention, the outlet of the mixing chamber being adapted to the intake line of the gasoline engine. This control system comprises a data processing unit with a microprocessor unit MPU which, in conjunction with a data storage unit DSEM (with EPROM and RAM), depends on those required by the vehicle driver

Output and engine speed regulates the metering valve and the control flap of the mixture formation device MFD as well as the ignition of the gasoline engine according to a stored program that corresponds to a map in a previously defined operating range of the gasoline engine.

In addition to the signal DI corresponding to the required power, the microprocessor unit MPU receives input signals on the one hand via corresponding sensors on the gasoline engine LE, which at least correspond to the engine speed RPM, the intake pressure IP and the cooling water temperature WT of the gasoline engine, and on the other hand receives additional input signals via sensors from the outside which correspond at least to the respective ambient pressure AP and the respective ambient temperature AT.

The microprocessor unit MPU in conjunction with the data storage unit DSEM, depending on these input signals DI, RPM, IP, WT, AP, AT, continuously gives corresponding control signals FM, MC or in accordance with the characteristic map in the previously defined operating range of the gasoline engine LE. IC for the control of the fuel metering valve and the servomotor of the control flap of the mixture formation device and the ignition of the gasoline engine.

In the limited operating range of the gasoline engine, the characteristic map precisely defines the setting of the control flap, the metering valve and the engine ignition for each operating point by means of predetermined values of the corresponding control signals (MC, FM, IC), so that the gasoline engine has a variable mixture composition in the entire operating range and maximum air excess can be optimally operated while reducing fuel consumption and pollutant emissions.

Such an automatic control system thus enables optimal vehicle operation with lean fuel mixtures, high efficiency and reduced fuel consumption while reducing pollutant emissions.

Thanks to the controllable mixture preparation according to the invention, a greatly simplified control system is achieved which, with the aid of only three control signals, enables optimal control of the lean-burn engine operation.

Both the composition and the amount of the fuel mixture and the ignition can be continuously and automatically adapted to the optimal conditions for the operation of the engine in question.

The mixture preparation and supply of gasoline engines provided with lean fuel mixtures according to the invention can also be supplemented with suitable means and measures such that the engine continues to work satisfactorily with high lambda values at ambient pressure even at very low load values.

For this purpose, for example, the exhaust valve camshaft could be adjusted accordingly such that the overlap of the valve opening on the intake and exhaust side ver5

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is increased, an excessive vacuum is prevented at the beginning of the intake process, because in this case a small part of the exhaust gases can be sucked back. This makes it possible to prevent an excessive increase in the pressure drop in the intake line and the excess air in the fuel mixture in a relatively simple manner.

On the other hand, the selective return of a small part of the exhaust gases into the intake line could be provided for the same purpose via a corresponding return line with a control valve.

The supply of gasoline engines with lean mixtures of variable composition according to the invention can also be supplemented in that a compressor is switched on before the air entry of the mixture generator at very high loads such that the lean mixture continues to operate with a high lambda value, reduced consumption and can ensure reduced pollutant emissions.

The control system can also be designed in such a way that the gasoline engine can only be briefly supplied with mixtures with a low lambda value of about 1 at very high loads.

Test bench tests were carried out in the context of the invention on a gasoline engine with a controllable mixture generator according to FIG. 1 in connection with a control system according to FIG. 3.

These tests were carried out in the US FTP75 cycle on a gasoline engine with the following features: displacement 1.6 l, 4 cylinders, 16 valves, bore 80 mm, stroke 77 mm, compression 11: 1, two camshafts, central spark plug position .

The results of these investigations have clearly shown that, thanks to the regulated supply of the gasoline engine according to the invention with lean mixtures of variable composition with a very high excess of air (with lambda values from 1.4 to 2.2), the gasoline engine with this relatively unfavorable USFTP75 cycle Nitrogen oxide emissions (without the addition of a reduction catalytic converter) as well as carbon monoxide emissions are reduced under the current USA exhaust gas limit standards, whereby at the same time the fuel consumption and thus the C02 emissions have been significantly reduced.

In addition, the connection of a relatively simple oxidation catalytic converter enables the oxidation of the hydrocarbons, so that the HC exhaust gas limit values can also be easily complied with.

The present invention offers a novel combination of advantages that are particularly important for the operation of gasoline engines with lean mixtures and can be summarized as follows.

a) The nitrogen oxide emission is largely reduced thanks to the engine operation provided according to the invention at very high lambda values.

b) The reduction in fuel consumption thanks to the formation of homogeneous mixtures approximately at atmospheric pressure, the largely reduced gas exchange losses, the operation with high lambda values and the improved combustion of the homogeneous, lean mixtures.

c) The gasoline engine responds immediately to transient load changes without any fuel enrichment due to the precise, infinitely variable control of the mixture quality or the lambda value with the aid of the metering valve in connection with the control flap.

d) The formation of homogeneous fuel mixtures with high lambda values is ensured with the aid of the atomizer with motor drive, which guarantees the perfect atomization and mixing of the liquid fuel with the entire intake air in all operating states of the gasoline engine.

e) The atomization and the mixture formation are independent of the amount of air sucked in and the suction pressure, which can be kept approximately the same as the ambient pressure.

f) Thanks to the active connection of the control flap with the fuel metering valve, the mixture formation and the transport of the mixture take place approximately at atmospheric pressure.

g) The mixture quality is regulated continuously and precisely with the help of the control flap in connection with the fuel metering valve, whereby the gasoline engine can be supplied with lean mixtures of variable composition practically at atmospheric pressure with a very large excess of air and operated optimally thanks to the mixture formation according to the invention.

h) The air-fuel ratio (lambda) can be varied over a wide range in such a way that the internal combustion engine can work efficiently in the entire operating range with very lean mixtures while reducing fuel consumption and improving the exhaust gas quality, so that a reduction catalytic converter or a regulated one Three-way catalyst becomes unnecessary.

Claims (1)

Claims 1.Method for the mixture preparation and the supply of gasoline engines with lean fuel-air mixtures of variable composition, liquid fuel being supplied to an atomizer in a mixing chamber with an air inlet and a mixture outlet connected to the intake line of the gasoline engine, characterized in: (a) that the mixture formation takes place essentially at ambient pressure, the mixing chamber with the atomizer limiting a flow path between the air inlet and the mixture outlet and being equipped with a control flap which is controlled in operative connection with a fuel metering valve in a previously defined operating range , in which the gasoline engine works with lean mixtures of variable composition, (b) that metered amounts of fuel are fed to the atomizer via the fuel metering valve, which are adjusted according to the required engine power so that the gasoline engine 5 10th 15 20th 25th 30th 35 40 45 50 55 60 65 6 11 CH 683 938 A5 12th can be operated in the specified operating range and (c) that, in conjunction with the metering valve, the composition of the mixture is continuously adjusted to the required output at the corresponding operating point with the help of the control flap so that the mixture formation and the transport of the mixture in the intake line of the gasoline engine can take place approximately at ambient pressure. 2. The method according to claim 1, characterized in that the said area for the operation of the gasoline engine with lean mixtures of variable composition and the highest possible excess air is delimited in advance by gradually scanning the operating range of the gasoline engine at different speeds and loads, whereby each determines the fuel consumption, the mixture and exhaust gas composition and the intake pressure, adjusts the control flap and sets up an engine map that determines the optimal position of the control flap at the corresponding operating points, so that when operating with the highest possible excess air in the operating range of the gasoline engine, the mixture preparation and supply of the gasoline engine takes place essentially at ambient pressure, the fuel consumption can be reduced and the pollutant emissions can be reduced. 3. The method according to claim 1 or 2, characterized in that the mixture for supplying the gasoline engine has a lambda value of at least 1.4. 4. The method according to any one of claims 1 to 3, characterized in that the atomization is carried out regardless of the amount of air with a rotating atomizer with a motor drive. 5. The method according to any one of claims 1 to 4, characterized in that the control valve is arranged at the mixture outlet. 6. Mixture formation device for performing the method according to claim 1 with an atomizer, characterized in: (a) that the atomizer consists of a cup (1) with a central hollow socket (2), a distribution plate (3) and a riser cylinder (4) with an upper spray edge (18), mounted on a drive shaft (5) and with a Drive motor (6) is connected, (b) that a central prechamber (7) is provided in the hollow connector (2), which is open at one end, has a bottom (8) at the other end and is connected to the upper distribution surface (14) of the distribution plate (3) , (c) that the inflow pipe (10) is equipped with a regulated fuel metering valve (27), its free end projects axially into the prechamber (7) without contact and its fixed outlet opening (11) at an axial distance from the bottom (8) of the Antechamber (7) is arranged centrally so that the fuel can emerge from this opening (11) unhindered and (d) that a control flap (28) with a servomotor (29) is provided, so that in connection with the fuel metering valve (27) with the help of this control flap (28) the composition of the mixture continuously provides the required power at a corresponding operating point can be adjusted so that the mixture formation and the transport of the mixture in the suction line can take place approximately at ambient pressure. 7. Device according to claim 6, characterized in that a fixed casing (20) for holding the atomizer cup (1) is provided so that it has an annular channel (23) between the air inlet with the wall (22) of the mixing chamber (21) (24) and the mixture outlet (25). 8. Device according to claim 6 or 7, characterized in that the wall (22) of the mixing chamber (21) is provided with a heating jacket (26) so that impinging fuel drops evaporate. 9. Device according to claim 6, 7 or 8, characterized in that the control flap (28) is arranged in the region of the mixture outlet (25) of the mixing chamber (21). 10. Device according to one of claims 6 to 9, characterized in that the free end of the drive shaft (5) is mounted in the hollow socket (2) and has an axial blind hole which forms the central prechamber (7) with the bottom (8). 11. Device according to one of claims 6 to 10, characterized in that the drive shaft (5) with the hollow connector (2) forms an annular intermediate chamber (12) which, via a first radial bore (13) with the central prechamber (7) and via a second radial bore (19) communicates with the distribution surface (14) of the plate (3). 12. The device according to claim 11, characterized in that the first and second bores (13 and 19) are diametrically opposite one another. 13. The device according to claim 7, characterized in that the drive motor (6) below the atomizer cup (1) and with this inside the casing (20) is arranged, the spray edge (18) standing free and spraying the fuel radially, so that it mixes with the intake air in the ring channel (23). 14. Device according to claim 13, characterized in that the atomizer cup (1) is covered by a hood (30) which widens from the air inlet (24) in the direction of the spray edge (16). 15. Device according to claim 6, characterized in: (a) that the outlet (25) of the mixing chamber (21) is adapted to the connection to the intake line (31) of the gasoline engine (LE), (b) that the device has a data processing unit with a microprocessor unit (MPU) which, in conjunction with a data storage unit (DSEM) depending on the power required by the gasoline engine (DI) and the engine speed (RPM), simultaneously the fuel metering valve (27 ) and the servomotor (29) of the control flap (28) of the mixture formation device (MFD) and the ignition of the gasoline engine 5 10th 15 20th 25th 30th 35 40 45 50 55 60 65 7 13 CH 683 938 A5 regulates according to a stored program that corresponds to a map in a previously defined operating range of the gasoline engine, (c) that the microprocessor unit (MPU), in addition to a signal (DI) corresponding to the power required by the gasoline engine (LE), receives input signals on the one hand via corresponding sensors on the gasoline engine (LE), which at least in each case correspond to the engine speed (RPM), the intake pressure ( IP) and the temperature (WT) of the gasoline engine, and on the other hand receives additional input signals from sensors that correspond at least to the respective ambient pressure (AP) and the respective ambient temperature (AT), (d) that the microprocessor unit (MPU) in connection with the data storage unit (DSEM) depending on these input signals (DI, RPM, IP, WT, AP, AT) according to the above-mentioned map in the previously defined operating range of the gasoline engine continuously corresponding Control signals (FM, MC, IC) for the control of the fuel metering valve (27), the servomotor (29) of the control flap (28) of the mixture formation device and the ignition of the gasoline engine and (e) that the mentioned map defines the setting of the control flap (28), the metering valve (27) and the engine ignition by predetermined values of the corresponding control signals (MC, FM, IC) for each operating point, so that the gasoline engine as a whole mentioned operating range with fuel-air mixtures of variable composition and maximum air excess while reducing fuel consumption and pollutant emissions can be operated optimally. 5 10th 15 20th 25th 30th 35 40 45 50 55 60 65 8th