DE4416014A1 - Improving cleaning of exhaust gases from internal combustion engines - Google Patents

Abstract

Device is claimed for improving the cleaning of the exhaust gas from an internal combustion engine by introducing air into the exhaust gas includes a gas jet pump (1) whose drive jet (2) is connected to the exhaust outlet of the engine and whose outlet (4) is connected to the gas cleaning device. The additional air is drawn in through the suction side (33) of the jet pump and mixed with the engine exhaust gas passing through it. Also claimed is a process for improving the cleaning of exhaust gases from internal combustion engines by the addition of air to the exhaust gas using a jet pump through which at least part of the exhaust gas passes.

Description

The invention relates to a method and a device to improve the purification of the exhaust gas of a cremation tion engine with an exhaust gas cleaning system, their on opening by means of an exhaust duct with a Exhaust outlet opening of the internal combustion engine connected is through the air supply connected to the exhaust duct medium, by means of which the exhaust gas in the exhaust duct air can be fed, in particular in a motor vehicle.

It is known to operate internal combustion engines resulting pollutant emissions by means of in the exhaust gas to reduce the current switched exhaust gas cleaning systems. For example, catalysts are found in gasoline engines with associated lambda sensor application and for diesel soot filters are used in motors. Especially at Motor vehicles are such exhaust gas cleaning systems,  to which the invention relates, on a large scale built.

Due to constantly tightening environmental protection you are always looking for ways the cleaning effect of the emission control system for white improve the reduction of pollutant emissions.

It is known that, in particular in the starting phase Gasoline engine a Kataly switched into the exhaust gas flow sator is unable to control the pollutants with a convert high efficiency. This is due to that cause a catalytic converter only from an operating point temperature of approx. 400 ° C is effective and this temperature not before 30 to 60 seconds after starting the engine is achieved. To shorten the time period until Reaching the operating temperature of the catalyst and there accompanied by a reduction in pollutant emissions To achieve, it was proposed to use the catalyst means of a heater independent of the engine heat. A burner can serve as the heating device, the air heated by the burner using a Blower introduced into the exhaust duct and thus the Catalyst is supplied. In this way, the Catalyst either before starting combustion motors are brought to their operating temperature or but if the internal combustion engine is already at the same time or started immediately after the burner was switched on the time until the operating temperature is reached rature of the catalyst can be reduced.

If the internal combustion engine is not running, a rela is sufficient tiv small amount of air from the burner heating flame to supply with air and the heated air through the exhaust supply gas channel to the catalyst. As soon as the scorching  engine runs, but is built into the exhaust duct high exhaust gas back pressure on the burner fan overcome for the supply of air to the heating flame got to. The exhaust gas back pressure of an internal combustion engine increases with increasing speed, which is why in the prior art is provided, the speed of the internal combustion engine The external heating by means of a burner never limit other speeds. But also in this case it is necessary that the blower against an exhaust gas counter pressure of about 70 to 120 mbar and about 50 up to 70 kg of air per hour. For this is an elek tric blower output of approx. 300 to 400 watts that loads the vehicle electrical system. In addition, the Ge inflate correspondingly large dimensions.

Another proposal for the external heating of a catalytic converter tors consists of heating it electrically. Also this requires high electrical power.

Another known proposal to reduce the Pollutant emission is the exhaust gas flow air to mix in order to achieve a thermal post-oxidation in to the exhaust gas flow contained fuel components target that in the burning process in the burning motor has not been burned or not completely burned. Air is added to the exhaust gas stream after the state of the art only in certain operating conditions the. This is because not all Operating conditions to a significant extent fuel Components are present in the exhaust gas flow. A wide one rer reason is that the elec vane pumps operated only a limited number Have lifespan and therefore not always switched on should be. These vane pumps can be high Generate pressures to work against the exhaust back pressure  ten, and have an adjustable delivery rate. You point even if they only promote a small volume, large dimensions, which are about the dimensions of the air filter belonging to the internal combustion engine. The admixture of air to the exhaust gas flow is both at Petrol engines for thermal post-oxidation of the rest fuel shares, as well as in diesel engines for ver burning of soot particles in the soot filter known.

The invention has for its object a method and to create a device with which to clean of the exhaust gas of an internal combustion engine with an exhaust gas series cleaning system can be further improved. Especially it focuses on the dimensions of the additional Units and the elec to keep performance as low as possible, especially is particularly advantageous in motor vehicles.

To solve this problem with a device of the The type described above is proposed according to the invention conditions that the air supply means comprise a gas jet pump sen, whose driving side by means of the exhaust duct with the Exhaust outlet opening of the internal combustion engine connected is whose outlet side by means of the exhaust duct with the Inlet opening of the exhaust gas cleaning system is connected and by means of the air supplied on its suction side it can be mixed with exhaust gas flowing through it.

To solve the problem in a method of the beginning designated type is proposed according to the invention that the air supply means comprise a gas jet pump, the Driving side by means of the exhaust duct with the exhaust connection of the internal combustion engine is connected, the Exit side by means of the exhaust duct with the inlet opening of the exhaust gas cleaning system is connected and the  flows through at least a partial flow of the exhaust gas and by means of the air supplied on its suction side is mixed with the exhaust gas flowing through it.

The exhaust gas flow flowing through the gas jet pump can the total exhaust gas flow of the internal combustion engine or else be a part of it. It causes on the suction side of the gas jet pump air is sucked in without a separate pump with large dimensions and high performance is required. The for the Air is added to the energy required Exhaust gas flow withdrawn itself.

Other advantageous features, individually or in Combination can be realized in the ab pending claims specified.

In some applications, the dim solutions of the suction jet pump become impractically large. In In these cases, it can be advantageous to use the suction side of the To connect gas jet pump with a supply air pump with Which air can be supplied. That way you can significantly reduced the dimensions of the suction jet pump without the necessary supply air pump has large dimensions. The design of the gas jet pump and the supply air pump can be used for the respective ver internal combustion engine to be adapted, for which calculations and can serve practical trials. The supply air pump can advantageously be operated electrically or have an adjustable delivery rate.

According to a further advantageous feature is pre hit that the suction side of the gas jet pump with a controllable throttle element is connected and the closing position of the throttle element by means of it  closed control device for controlling the supplied Air volume is adjustable. In this way, the means the amount of air supplied to the gas jet pump Operating conditions of the internal combustion engine can be adjusted.

Another advantageous feature is that the Suction power of the gas jet pump is adjustable to the Regulate the amount of air supplied to the exhaust gas flow. This can happen with for example, that the gas jet pump a nozzle needle-controlled propellant nozzle.

According to a preferred feature of the invention is pre beat that on the exhaust duct between the exhaust opening of the internal combustion engine and the entrance opening of the exhaust gas cleaning system a burner connected sen, which is a controllable fuel supply device for supplying fuel to a combustion chamber, a combustion air opening for air supply to the combustion chamber and a ignition direction includes. With such a burner, as in Known in the prior art, the exhaust gas cleaning system heated or in less time to their operating temperature to be brought.

According to additional advantageous features can be provided be that the fuel supply to the burner by means of a fuel metering element and one attached to it closed control device is adjustable that the burner room is connected to a burner pump by means of the burner air can be supplied that the burner pump is electrically operated or that the delivery rate of Burner pump is adjustable. Another beneficial one Training feature is still that the burner is connected to a controllable burner throttle element and the closed position of the burner throttle element with means of a control device connected to it  Regulation of the amount of air supplied to the burner adjustable is.

A particularly advantageous training is that the combustion chamber of the burner with the suction side of the gas jet pump is connected. It can also be advantageous tually be provided that the same pump both Supply air pump as well as burner pump.

A particularly space-saving and inexpensive construction the device according to the invention can be achieved if part of the wall of the burner combustion chamber by a part of the wall of the gas jet pump, in particular from part of the driving nozzle is formed.

If the dimensions of the gas jet pump for each the place of use or installation prove to be too large should it be possible to make the gas jet pump from several separate single gas jet pump that can be operated in parallel to form pen, their respective dimensions accordingly are smaller. The individual gas jet pumps can also be designed differently and individually or in Combination operated.

For security reasons, it is also proposed that the suction side of the gas jet pump and / or the combustion air a check valve is connected to the opening of the burner is to prevent the leakage of exhaust gas other than through to prevent the emission control system.

Through the inventive design of the method and the device ensures that a continuous Air can be added to the exhaust gas flow without that this is a large and powerful electric Pump is required. Furthermore, before the start  of the internal combustion engine or in its start or warm run phase at any speed with a anyway small auxiliary pump with low power, external heating the exhaust gas cleaning system with a burner become.

Let the following embodiments of the invention Recognize further advantageous features and special features nen, based on the representation in the drawings in following are described and explained in more detail.

Show it

Fig. 1 is a schematic diagram of a gas jet pump in section,

Fig. 2 shows an inventive device in a motor vehicle,

Fig. 3 in a detail to Fig. 2, a gas jet pump with the burner in section,

Fig. 4 is a modified embodiment of FIG. 3,

Fig. 5 shows the exhaust backpressure in a gasoline engine,

Fig. 6, the exhaust gas volume and the volume of supply air in a spark ignition engine and the suction power of a gas jet pump,

Fig. 7, the exhaust gas volume to Fig. 6 in other representation,

Fig. 8 shows the exhaust gas composition in a gasoline engine, and

Fig. 9, the exhaust gas temperature in a gasoline engine.

In Fig. 1 the schematic diagram of a commercially available gas jet pump 1 is shown in section. It has no moving parts and does not require a drive unit. It usually consists of a housing 5 , a driving nozzle 6 and a mixing nozzle 7 . The propellant gas supplied on the propellant side 2 is expanded in the propellant nozzle 1 while reducing the pressure. As a result, the gas fed to the suction side 3 is entrained or sucked in and mixed in the mixing nozzle 7 with the propellant gas. The mixing nozzle 7 has a confuser 8 , which can be conical or cylindrical in shape as in the example shown, and a diffuser 9 , in which a speed reduction of the gases and a pressure increase takes place. The gas emerges at the outlet side 4 . Gas jet pumps which are designed as gas jet fans are particularly suitable for the application according to the invention. In these, the pressure difference between the outlet side 4 and the suction side 3 is low.

The gas jet pump 1 must be designed in a specific manner for the respective application, ie the dimensions and contour shapes must be designed to be application-specific. In a certain design of the gas jet pump 1 with respect to the prevailing Druckver ratios on the drive side 2 , suction side 3 and outlet side 4 must, with an increase in their diameter to increase the gas flow rate, also increase their length. If the gas jet pump 1 is then too long for the respective application, the gas jet pump 1 can be formed from a parallel connection of several, each complete gas jet pumps. In general, gas jet pumps have round cross sections, for. B. the mixing nozzle. However, it can also be provided that the cross-section is not round to increase the volume throughput with a short overall length of the gas jet pump, but is laid out as a rectangular flat cross-section, thereby increasing the overall width.

FIG. 2 shows an inventive device in a motor vehicle. A four-cylinder internal combustion engine 11 is shown , the exhaust gases of which on the outlet side 21 exit at an exhaust gas outlet opening 12 into the exhaust duct 13 . The exhaust duct 13 directs the gases to the inlet opening 23 of a catalyst 14 . A lambda probe 15 is arranged in the exhaust duct 13 . The internal combustion engine 11 is supplied with fuel from the fuel tank 16 by means of the fuel line 17 on the inlet side 20 . In the fuel line 17 , a fuel pump 18 and a fuel filter 19 are inserted. On the inlet side 20 , the internal combustion engine 11 is supplied with air, which can be measured via an air flow meter 22 . The air flow meter 22 can be connected to a control device 30 .

In the exhaust duct 13 , a gas jet pump 1 is inserted, which is connected on its drive side 2 with the exhaust gas outlet opening 12 and on its outlet side 4 with an inlet opening 23 . The suction side 3 of the gas jet pump 1 is connected to the combustion chamber 33 of a burner 31 .

The burner 31 is supplied with fuel by means of the fuel line 17 . In the fuel supply to the burner 31 , a controllable fuel supply device 32 , which is connected to the control device 30 , and a controllable fuel metering element 36 are switched on. The control of the fuel metering element 36 can take place, for example, with an electronic control device 30 . An alternative control device for the fuel metering element 36 can also respond to the differential pressure between the fuel line 17 and the air line 25 , which is measured by means of the pressure line 24 .

The air for the operation of the burner 31 in the combustion chamber 33 is supplied via an air line 25 . The Luftlei device 25 is connected to a supply air pump 26 for the supply of air to the suction side 3 of the gas jet pump 1 to the. The power of the supply air pump 26 can be controlled by means of the control device 30 . It also serves as a burner pump 37 for supplying air to the burner 31 . Between the supply air pump 26 and the combustion chamber 33 , a controllable throttle element 27 is arranged for controlling the amount of air supplied to the suction side 3 of the gas jet pump 1 . This controllable throttle element 27 also serves as a controllable throttle element 38 for controlling the amount of air supplied to the burner 31 . It is controlled by the control device 30 .

The controllable throttle element 27 also has a check valve 28 with which the escape of exhaust gas from the exhaust duct 13 through the air line 25 is prevented. It also fulfills the function as a further check valve 39 , with which the escape of heating air from the combustion chamber 33 through the air line 25 is prevented.

The function of the device shown is as follows: If the internal combustion engine 11 is cold and the catalyst 14 does not have the required operating temperature, the fuel pump 18 and the burner pump 37 are first put into operation. This can be done automatically, for example, by switching on the ignition system of the internal combustion engine 11 . At the same time, the controllable burner throttle element 38 opens.

As a result, air is initially blown into the combustion chamber 33 at a low pressure and from there via the exhaust duct 13 into the catalytic converter 14 . The fuel metering element 36 then opens and fuel flows to the burner 31 . At this time, the burner 31 is ignited by means of the ignition device 35 and begins to heat the air present in the combustion chamber 33 . The constant supply of further air through the burner pump 37 leads the hot air into the catalyst 14 and heats it up.

When the engine is started, the pressure in the exhaust passage 13 increases . However, the supply air pump 26 does not have to work against this exhaust gas counterpressure because the pressure is reduced on its suction side 3 due to the suction effect of the gas jet pump 1 . As a result, both the hot air is conveyed from the combustion chamber 31 into the exhaust duct 13 and the supply air pump 26 is relieved, as a result of which it can be designed with a low output and small size.

Depending on the design of the supply air pump 26 and gas jet pump 1 , a certain controllable amount of air can now pass through the combustion chamber 33 into the exhaust gas duct 13 and there burn the unburned fuel residues present in the exhaust gas stream to a particularly high extent in the cold start phase. The heat released in the process can contribute to faster heating of the catalyst 14 . As a result, pollutant emissions are also reduced in this operating section. Furthermore, the output of the burner 31 can be correspondingly lower.

Thermal post-combustion is particularly efficient when the flame with excess air present is drawn from the combustion chamber 33 of the burner 31 through the suction side 3 of the gas jet pump 1 into the exhaust gas stream in the gas jet pump 1 .

The amount of fuel supplied to the burner can be regulated in a suitable manner by means of the controllable fuel metering element 36 according to the respective requirement. The same applies to the air supply to the burner 31 or the suction side 3 of the gas jet pump 1 , which can be controlled by means of the controllable throttle element 27 or controllable Brennerdros selelementes 38 or the power of the supply air pump 26 or the burner pump 37 .

When the catalytic converter 14 has reached its operating temperature, the controllable fuel supply device 32 can be closed, whereby the burner 31 is switched off. The operating temperature of the catalytic converter 14 is then maintained by the exhaust gas flow from the internal combustion engine 11 . The exhaust gas stream can be supplied via the gas jet pump 1 on its suction side 3 continuously or in certain operating states of the internal combustion engine 11 air for post-oxidation of the exhaust gases. The air volume can be regulated as explained above. In an analogous manner, the air supplied can also be used for the combustion of soot particles in a diesel engine, which has a soot filter instead of the catalyst 14 .

In Fig. 3, the gas jet pump 1 with the burner 31 is shown in detail in Fig. 2 in section. The arriving on the drive side 2 of the internal combustion engine 11 exhaust gas stream is expanded in the drive nozzle 6 and mixed with the air supplied on the suction side 3 in the mixing nozzle 7 . The mixture exits the gas jet pump 1 at the outlet side 4 and is passed from the exhaust duct 13 to the inlet opening 23 of the catalyst 14 . The air is supplied to the suction side 3 via an air line 25 . It first passes through a combustion air opening 34 into a combustion chamber 33 , in which it can be heated by means of the burner 31 . The burner 31 has an ignition device 25 and is supplied with fuel by means of a fuel line 17 . The suction side 3 of the gas jet pump 1 is only open to the combustion chamber 31 , to which air can only be supplied via the air line 25 . In this way, only air supplied through the air line 25 is admixed to the exhaust gas stream, so that the amount of air supplied can be controlled.

The air stream admixed by the gas jet pump 1 can in principle be influenced in three ways. The first consists in varying the pressure on the suction side, which can be done by means of a controllable throttle element 27 in the air line 25 or by regulating the power of the supply air pump 26 . Second, the suction flow can also be influenced by varying the pressure on the outlet side of the gas jet pump 1 . In practice, however, this possibility is likely to be less significant because the exhaust gas flow is to emerge largely unthrottled. The third option is to vary the propellant pressure. There are basically two options available for this. On the one hand, the propellant gas pressure itself could be changed, which can be done by throttling or increasing the pressure. Limits are also set for this in practice in that the exhaust gas pressure is essentially predetermined by the internal combustion engine 11 and cannot be throttled or increased as desired.

The second possibility for varying the propellant gas pressure can be done by a modified design of the suction jet pump 1 , which is shown in FIG. 4. It has a nozzle needle-controlled driving nozzle with a nozzle needle 10 , which can be moved back and forth to enlarge or reduce the cross section available for the exhaust gas flow by means of a control device, not shown. As a result, a quantity influence is possible while maintaining the pressure on the drive side 2 due to the change in cross section. Such a nozzle needle 10 can be used in particular at low speeds of the internal combustion engine 11 to reduce the cross-sectional area of the driving nozzle 1 in order to achieve a sufficient suction effect on the suction side 3 even in this case if the exhaust gas flow on the driving side 2 at the low speeds is small and would otherwise not or only in a small way be sufficient to achieve a sufficient suction effect.

In the embodiment shown in FIGS. 3 and 4 gas jet pump 1, the gas jet pump 1 and the combustion chamber 33 of the burner 31 a common part 41 of the wall 40. In this way, the gas jet pump 1 with burner 31 can be constructed in a particularly space-saving and cost-effective manner.

The gas jet pump 1 must be designed separately for the respective application, since there is no universal gas jet pump 1 . In the proposed applications, for example, the pressures or pressure differences present on the drive side 2 , suction side 3 and outlet side 4 of the gas jet pump 1 , the respective volume or mass flows, the temperature of the gases and the gas type or gas composition to be taken into account. These quantities in turn depend on other parameters, which include the type of the respective combustion engine 11 , the amount of air to be mixed with the exhaust gas, the power of the supply air pump 26 , the amount of fuel burned by the burner 31 and the amount of air supplied to the burner 31 . In FIGS. 5 Who a six cylinder engine with 3199 cc capacity than full load curve at Lamda indicated to 9 the typical characteristics equal to 1.0, with which it is possible to those skilled in the art of gas jet pumps, the dimensions and the Kon turformen a suitable gas jet pump 1 for interpret this exemplary application.

In FIG. 5, the exhaust backpressure AG of the gasoline engine is shown as a function of the speed of the motor. He is known that the engine has a low exhaust gas back pressure at low speeds, which increases sharply with increasing speed. Air supply means must overcome this exhaust gas back pressure if air is to be mixed with the exhaust gas.

In Fig. 6, the associated exhaust gas volume VA of the internal combustion engine 11 is shown, which also increases with the speed. The diagram also shows the supply air volume VZ, which indicates the amount of air that must be mixed with the exhaust gas stream for complete thermal afterburning of residual fuel in the exhaust gas stream. Also shown is the suction power SL of the gas jet pump 1 , which is advantageously larger than the supply air volume VZ in at least a predominant speed range, so that the required supply air volume VZ can be adjusted in the respective operating states by throttling the suction power SL of the gas jet pump 1 .

In the example shown in FIG. 6, the suction power SL of the gas jet pump 1 in the area B2 is greater than the supply air volume VZ because the exhaust gas flow is strong enough at the higher speeds. In this example, the amount of air supplied can be reduced to the desired value by the various throttling measures described above.

In the area B1 at low speeds, the suction power SL of the gas jet pump 1 alone is smaller than the supply air volume VZ. In this area, the gas jet pump 1 can be supported by a supply air pump 26 connected to its suction side 2 in order to supply the required amount of air to the exhaust gas stream without the gas jet pump 1 or the supply air pump 26 becoming too large.

Fig. 7 shows the exhaust gas volume VA as a mass flow in kilograms per hour and in Fig. 8 the exhaust gas volume VA is shown together with its components.

Fig. 9 shows the exhaust gas temperature of the engine.

Claims (32)

1. A device for improving the cleaning of the exhaust gas from an internal combustion engine ( 11 ) with an exhaust gas cleaning system ( 14 ), the inlet opening ( 23 ) of which is connected to an exhaust gas outlet opening ( 12 ) of the internal combustion engine ( 11 ) by means of an exhaust gas channel ( 13 ) to the exhaust duct ( 13 ) is connected air supply means by means of which the exhaust gas in the exhaust duct ( 13 ) can be supplied with air, characterized in that the air supply means include a gas jet pump ( 1 ), the drive side ( 2 ) of which with the exhaust outlet opening ( 12 ) of the internal combustion engine ( 11 ) is connected, the outlet side ( 4 ) of which is connected to the inlet opening ( 23 ) of the exhaust gas cleaning system ( 14 ) and by means of the air supplied on its suction side ( 3 ), the exhaust gas flowing through it can be mixed. 2. Device according to claim 1, characterized in that the suction side ( 3 ) of the gas jet pump ( 1 ) with egg ner supply air pump ( 26 ) is connected, by means of which air can be supplied. 3. Device according to claim 2, characterized in that the supply air pump ( 26 ) is electrically operated. 4. The device according to claim 2, characterized in that the delivery rate of the supply air pump ( 26 ) is adjustable. 5. The device according to claim 1, characterized in that the suction side ( 3 ) of the gas jet pump ( 1 ) with egg nem controllable throttle element ( 27 ) is connected and the closed position of the throttle element ( 27 ) by means of a connected control device ( 30 ) for controlling the amount of air supplied is adjustable. 6. The device according to claim 1, characterized in that the suction power of the gas jet pump ( 1 ) is adjustable. 7. The device according to claim 6, characterized in that the gas jet pump ( 1 ) has a nozzle needle-controlled driving nozzle ( 10 ). 8. The device according to claim 1, characterized in that a burner ( 31 ) is connected to the exhaust duct ( 13 ) between the exhaust outlet opening ( 12 ) of the internal combustion engine ( 11 ) and the inlet opening ( 23 ) of the exhaust gas cleaning system ( 14 ) Controllable fuel supply device ( 32 ) for supplying fuel to a combustion chamber ( 33 ), a combustion air opening ( 34 ) for supplying air to the combustion chamber ( 33 ) and an ignition device ( 35 ). 9. The device according to claim 8, characterized in that the fuel supply to the burner ( 31 ) by means of a fuel metering element ( 36 ) and a control device ( 30 ) connected to it is controllable. 10. The device according to claim 8, characterized in that the combustion chamber ( 33 ) is connected to a burner pump ( 37 ) by means of which the burner ( 31 ) air can be guided. 11. The device according to claim 10, characterized in that the burner pump ( 31 ) is electrically operated. 12. The apparatus according to claim 10, characterized in that the delivery rate of the burner pump ( 31 ) is adjustable. 13. The apparatus according to claim 8, characterized in that the burner ( 31 ) is connected to a controllable burner throttle element ( 38 ) and the closed position of the burner throttle element ( 38 ) by means of egg ner connected control device ( 30 ) for controlling the burner ( 31 ) supplied air volume is adjustable. 14. Device according to claims 2 and 8, characterized in that the combustion chamber ( 33 ) of the burner ( 31 ) with the suction side ( 3 ) of the gas jet pump ( 1 ) is connected. 15. Device according to claims 2 and 8, characterized in that the same pump is both the supply air pump ( 26 ) and the burner pump ( 37 ). 16. The apparatus according to claim 8, characterized in that a part ( 41 ) of the wall ( 40 ) of the combustion chamber ( 33 ) of the burner ( 31 ) from a part ( 41 ) of the wall ( 40 ) of the gas jet pump ( 1 ), in particular of a part ( 41 ) of the driving nozzle ( 6 ) is formed. 17. The apparatus according to claim 1, characterized in that the gas jet pump ( 1 ) from a plurality of separate, parallel gas jet pumps ( 1 ) is formed. 18. The apparatus according to claim 1, characterized in that a check valve ( 39 ) is connected to the suction side ( 3 ) of the gas jet pump ( 1 ). 19. The apparatus according to claim 8, characterized in that a check valve ( 39 ) is connected to the combustion air opening ( 34 ) of the burner ( 31 ). 20. A method for improving the cleaning of the exhaust gas of an internal combustion engine ( 11 ) with an exhaust gas purification system ( 14 ), the inlet opening ( 23 ) of which is connected by means of an exhaust duct ( 13 ) with an exhaust gas outlet opening ( 12 ) of the internal combustion engine ( 11 ) to the exhaust gas duct ( 13 ) connected air supply means by means of which the exhaust gas in the exhaust gas duct ( 13 ) is supplied with air, characterized in that the air supply means include a gas jet pump ( 1 ), the drive side ( 2 ) of which with the exhaust gas outlet opening ( 12 ) of the internal combustion engine ( 11 ) is connected, the outlet side ( 4 ) of which is connected to the inlet opening ( 23 ) of the exhaust gas cleaning system ( 14 ) and which is flowed through by at least a partial flow of the exhaust gas, and is supplied by means of the suction side ( 3 ) thereof Air to which it is mixed by flowing exhaust gas. 21. The method according to claim 20, characterized in that by means of a with the suction side ( 3 ) of the gas jet pump ( 1 ) connected supply air pump ( 26 ) of the suction side ( 3 ) of the gas jet pump ( 1 ) air is supplied. 22. The method according to claim 20, characterized in that the supply air pump ( 26 ) is electrically operated. 23. The method according to claim 20, characterized in that the delivery rate of the supply air pump ( 26 ) is regulated. 24. The method according to claim 20, characterized in that by means of a controllable throttle element ( 27 ) and an attached control device ( 30 ) the suction side ( 3 ) of the gas jet pump ( 1 ) supplied air quantity is controlled. 25. The method according to claim 20, characterized in that the suction power of the gas jet pump ( 1 ) is regulated. 26. The method according to claim 25, characterized in that the suction power of the gas jet pump ( 1 ) is regulated by means of a nozzle needle-controlled driving nozzle ( 10 ). 27. The method according to claim 20, characterized in that by means of a in the exhaust duct between the gas outlet opening ( 12 ) of the internal combustion engine ( 11 ) and the inlet opening ( 23 ) of the exhaust gas cleaning system ( 14 ) arranged burner ( 31 ) by means of egg ner controllable fuel supply device ( 32 ) is supplied with fuel and air by means of a combustion air opening ( 34 ) and which comprises an ignition device ( 35 ) which heats gas in the exhaust gas duct ( 13 ). 28. The method according to claim 27, characterized in that the fuel supply to the burner ( 31 ) is controlled by means of a fuel metering element ( 36 ) and a control device ( 30 ) connected thereto. 29. The method according to claim 27, characterized in that air is supplied to the burner ( 31 ) by means of a burner pump ( 37 ). 30. The method according to claim 29, characterized in that the burner pump ( 37 ) is operated electrically. 31. The method according to claim 29, characterized in that the delivery rate of the burner pump ( 37 ) is regulated. 32. The method according to claim 27, characterized in that with a controllable burner throttle element ( 38 ) and a control device ( 30 ) connected to it, the amount of air supplied to the burner ( 31 ) is regulated.