WO2010070100A1

WO2010070100A1 - Exhaust gas cleaning system and method for operating an exhaust gas cleaning system

Info

Publication number: WO2010070100A1
Application number: PCT/EP2009/067526
Authority: WO
Inventors: Hermann-Josef Schulte
Original assignee: Hjs Fahrzeugtechnik Gmbh & Co Kg
Priority date: 2008-12-19
Filing date: 2009-12-18
Publication date: 2010-06-24
Also published as: DE102008063809A1; DE102008063809B4

Abstract

An exhaust gas cleaning system 6, in particular for a diesel internal combustion engine 1, comprises at least one exhaust gas cleaning unit 9 installed in the exhaust line 7. The exhaust gas cleaning system 6 also comprises a device for introducing thermal energy to the exhaust line 7 for initiating and/or supporting a process that is in connection with the exhaust gas cleaning. The device comprises a secondary flow line 15 that runs parallel to the exhaust line 7. Due to the arrangement of the secondary flow line relative to the exhaust line 7 and/or through the use of a heating unit installed therein on the outlet side, exhaust gas can be fed from said secondary line to the exhaust line 7, the exhaust gas being at a temperature that is higher than the exhaust gas temperature in the exhaust line 7. To introduce the thermal energy, the secondary flow line 15 opens up on the outlet side at or in the area of the exhaust line section in which the thermal energy is needed. A particle filter unit 9 is installed in the exhaust line 7 as an exhaust gas cleaning unit. An actuator 13 is assigned to the particle filter unit 9, said actuator being installed ahead of the filter surface provided by the unit 9. This actuator blocks and/or reduces the exhaust gas feed from the exhaust line 7 in at least one segment 10, 10.1. The outlet side opening of the secondary flow line 15 is connected after the actuator 13 and ahead of the filter surface. The invention further describes a method for introducing thermal energy for initiating and/or supporting a process in an exhaust gas cleaning system 6, in particular of a diesel internal combustion engine 1. According to this method, wherein a particle filter unit 9 is provided as an exhaust gas cleaning unit, a regeneration of the filter unit is done in segments, wherein the hotter exhaust gas fed through the secondary stream is fed to the segment of the particle filter that is separate from the main exhaust gas stream so that the oxidation of soot is initiated or supported in said segment.

Description

Emission control system and method for operating an emission control system

The invention relates to an exhaust gas purification system, in particular for a diesel internal combustion engine comprising at least one switched on in the exhaust gas emission control unit and means for supplying thermal energy in the exhaust line for triggering and / or supporting a standing in connection with the exhaust gas purification process, which means a to the Exhaust line parallel extending bypass line includes, from which bypass line due to their arrangement to the exhaust system and / or by an activated therein heater on the output side exhaust gas in a relative to the exhaust gas temperature in the exhaust line higher temperature to the exhaust line can be fed and which bypass line output side for supplying thermal energy in the exhaust system or in the region of that exhaust gas section opens, in which the thermal energy is needed. Furthermore, the invention relates to methods for supplying thermal energy for triggering and / or supporting a running in an exhaust gas purification system, in particular a diesel engine process, wherein a part of the exhaust side exhausted from the exhaust stream branched off as a side stream and at that point in the exhaust system again is introduced, is required at the thermal energy for triggering and / or supporting an associated with the exhaust gas purification process, this process is a regeneration of a particulate filter unit and the exhaust gas supplied via the secondary flow at a higher temperature than that not through Having the secondary flow of flowing exhaust gas.

Diesel engines are equipped with emission control systems to reduce harmful emissions. The exhaust gas discharged from such a diesel engine is passed through such an exhaust gas purifier for this purpose. The exhaust gas purification system comprises an exhaust gas line, in which one or more exhaust gas purification units are switched on. To remove entrained in the exhaust gas of a diesel engine soot can in the exhaust system Particle filter be turned on. On the upstream surface of the particulate filter accumulates in the exhaust soot accumulates. So that in the course of the successive Rußakkumulation the exhaust back pressure does not rise too far or the filter clogged, with sufficient soot loading of the filter, a soot oxidation (Rußabbrand) is brought about. Upon completion of such soot oxidation, the particulate filter is regenerated. What remains is a non-combustible ashes. For soot oxidation to take place, the soot must have a certain temperature. Since, depending on the operation of the diesel internal combustion engine, the necessary temperature for triggering a Rußabbrandes is not always achieved, it may be necessary to otherwise supply thermal energy for triggering a regeneration process. This takes place either by heating the filter body or its upstream surface with the aid of electrical heating elements or by heating the exhaust gas flowing into the filter by using burners and / or oxidation catalysts, which are supplied with fuel to increase the exhaust gas temperature.

Based on this discussed prior art, the invention is therefore the object of proposing an exhaust gas purification system, in particular for a diesel engine, and a method for supplying thermal energy for triggering and / or supporting a standing in connection with the exhaust gas purification process, with which system or with which method an energy supply for the above-described purposes is primarily simplified.

The system-related object is achieved by a generic emission control system mentioned in the introduction, in which in the exhaust gas system as exhaust gas purification unit a particulate filter unit with at least one of the provided by the particulate filter unit vorgealte- th actuator for blocking and / or reducing the exhaust gas supply from the exhaust system in at least one segment is arranged and that the output-side mouth of the bypass line downstream of the actuator and the filter surface is connected upstream.

The method-related object is achieved by a generic method mentioned at the outset, in which the particle filter unit is subjected to regeneration in segments and the sidestream waste is removed. gas upstream of a separated by an actuator of the main exhaust gas flow segment of the particulate filter for triggering and / or supporting a soot oxidation in this segment is supplied.

In this emission control system - the same applies to the claimed method - a secondary stream, preferably as close to the engine as possible, for example, from the manifolds, diverted from the main exhaust gas stream flowing through the exhaust line and passed through a bypass line. The bypass line is designed to flow parallel to the exhaust line in terms of flow. The bypass line in turn opens on the output side or in the region of the exhaust line in this where thermal energy is to be supplied. In this way, exhaust gas at a temperature in the exhaust line or directly to one or more, in the exhaust line switched exhaust gas purification units can be supplied at the or the mouth areas of such a bypass line. This exhaust gas supplied via the bypass line has a temperature which can be higher by more than 100 ^° C. during operation of the diesel internal combustion engine even without the use of an additional heating unit switched into the bypass line than the exhaust gas flowing through the exhaust line in the region of the outlet of the bypass line. This is the case when in the exhaust line, an exhaust gas turbine for driving a charge air compressor turned on and the bypass line is provided as a bypass with respect to the exhaust gas turbine. In many cases, modern diesel engines have a charge air compressor driven by an exhaust gas turbine. This is due to the fact that the inclusion of an exhaust gas turbine in the exhaust system leads to a reduction of the exhaust gas temperature. Thus, thermal energy can be introduced into the exhaust gas flow in this way in principle without additional devices via such a bypass line in order to trigger and / or assist exhaust gas purification processes, in this case a regeneration of a particle filter unit.

With the above-described emission control system and according to the above-described method, if part of the exhaust gas purification system is an SCR catalyst, a treatment of the required reducing agent for SCR catalysis, here: urea from an aqueous urea solution, are supported within the exhaust line. This - A -

This is followed by using, instead of ambient air to assist the urea solution atomization, such hot exhaust gas supplied via the bypass duct for this process. In this way, not only the necessary gas, but also thermal energy is supplied to the atomization of the urea solution. As a result of the supply of hot exhaust gas from the bypass flow flowing over the bypass line, a thermolytic splitting of the urea solution relative to the flow path of the same takes place in the exhaust gas line over a shorter distance. A urea-requiring exhaust gas purification unit comprising a urea supply device and an SCR catalytic converter connected downstream thereof can be designed to be correspondingly more compact. Against the background of motor vehicles or construction machines only small available space a compact design is advantageous.

The branching off of a part of the main exhaust gas stream for forming a secondary stream flowing through the bypass pipe further has the advantage that, if the temperature of the secondary exhaust gas provided on the engine side is insufficient, this exhaust gas flowing in the secondary stream is small due to its comparatively small amount and thus small and easy-to-build units can be additionally heated. If this is desired, a heating unit is switched on in the bypass line. This may be, for example, a flame burner, which may be followed by an oxidation catalytic converter, or else a catalytic burner, and consequently an oxidation catalytic converter with a fuel supply upstream of it in the direction of flow. If an oxidation catalytic converter is connected downstream of the burner, this is ultimately also a catalytic burner, since the upstream flame burner serves to heat the oxidation catalytic converter to its operating temperature. With the use of a burner and a downstream of this in the flow direction of the secondary flow in the bypass line oxidation catalyst, a temperature increase in the secondary flow is achieved in principle by conventional means, but with the difference that only a significantly smaller volume flow is to be heated in the bypass, thus the burner and / or the oxidation catalyst can be designed accordingly small, inexpensive and reliable. In particular, it is in such, in the Burner arranged burner arranged to introduce via this by a so-called over-fuel injection into the secondary stream for supplying the same to the likewise arranged in the bypass oxidation catalyst. Due to the complexity of such burners in the main exhaust gas flow, this is not possible, at least not in the required amount, so that in the case of such heating in the main exhaust gas flow, an additional fuel supply device is usually necessary.

The sidestream flowing over the bypass duct is used to supply the heat transported therein to a particle filter which is switched into the exhaust gas line for the purpose of its regeneration. For this purpose, the filter surface of a particle filter unit which is switched into the exhaust gas line is subdivided or subdivided into individual segments. The division of the total filter surface area provided by the particle filter unit into individual segments takes place against the background of not performing a regeneration of the particulate filter unit as a whole but segment by segment. At least one actuator is associated with such a particle filter unit, with which the exhaust gas supply via the main exhaust gas flow to the segment can be blocked or reduced, thus this segment is fluidly shadowed from the main exhaust gas stream. Associated with each segment of the particulate filter means is an outlet of the bypass duct so that each segment, when separated from the main exhaust stream, is triggered by the thermal energy supplied via the bypass duct to induce soot oxidation or to assist in the initiation of soot oxidation and / or control the soot oxidation can be used. Expediently, the size of the filter segments, based on the inflow-side end face portion thereof and the thermal energy supplied via the bypass line or the hot exhaust flow flowing in via the bypass line, are matched to one another.

The particle filter unit may be associated with an oxidation catalyst, which is connected upstream of the particle filter in the flow direction of the exhaust gas.

Such, separated by the actuator of the main exhaust gas flow or abgeschattetes segment by supplying the thermal energy heated via the sidestream of the bypass line, preferably without that cooler exhaust gas from the exhaust gas stream flowing through the main exhaust gas stream enters the segment. If the thermal energy supplied via the bypass line is insufficient for triggering a soot burn, then as described above, a heating unit can be switched on in the bypass line. It is also possible to assign one or more electrical heating elements to the individual segments of the particulate filter unit, respectively, in order to bring about an increase in temperature of the accumulated soot to the soot oxidation temperature. It is understood that due to the segmentation of the particulate filter device and the segmental regeneration of the same, the electrical energy required for each segment is lower compared to heating an entire particulate filter. As a result of the hot side stream supplied to the respective segment for triggering or carrying out a soot burn-off, only a part of the otherwise required thermal energy needs to be supplied via the heating elements. The use of electrical heating elements with a relatively low power in each segment is therefore sufficient for the regeneration of such a particulate filter with additional energy supply by the bypass line.

About the bypass line and the oxygen required for the soot oxidation can be supplied. Depending on the operation of the same, a residual oxygen content of 6-18% is present in the exhaust gas emitted by the internal combustion engine, in particular a diesel internal combustion engine. Typically, a control valve is switched into the bypass line, via which the volume flow flowing through the bypass line can be controlled. Thus, upon exposure of a particulate filter segment to the sidestream from the sidestream conduit, these segments can be supplied with not only thermal energy but also the oxygen needed for soot oxidation. If the soot oxidation is ignited, the oxidation process is observed, in particular with regard to its temperature, since excessive heat generation in connection with the soot oxidation can damage the particle filter. If excessive heat generation of the particulate filter segment involved in the regeneration is detected, the volumetric flow supplied and thus the supplied oxygen can be reduced via such a control valve. The same applies vice versa: If the temperature drops too low, the soot oxidation process can be rekindled by further opening such a control valve and thus by supplying additional oxygen. Instead of or together with this measure, the particle filter segment upstream actuator for shading this located in the regeneration particle filter segment can be opened accordingly, so that can be dissipated by the then flowing relatively cool exhaust gas from the main exhaust gas heat from the located in the regeneration particle filter segment.

As the particulate filter upstream actuator can serve a pivoting flap, which can be brought into a different position by a controlled by a control device controlling the exhaust gas purification. The different positions include that the entire filter surface of the particulate filter or the particulate filter unit is flowed through by exhaust gas flowing out of the exhaust line, so that all the segments are exhaust gas flows through. In other positions, one or more segments of the particulate filter are shadowed from the main exhaust stream. Also possible is an embodiment in which this actuator is designed as a rotatably mounted aperture. Such a diaphragm has a passage opening for the passage of the inflowing exhaust gas. The area shaded by the diaphragm in one of its positions then forms that segment of the filter which is fluidly shaded by the inflowing exhaust gas flow.

The invention is described below by means of embodiments with reference to the accompanying figures. Show it:

1 is a schematic representation in the manner of a block diagram of a diesel engine with an exhaust gas purification system according to a first embodiment,

2 shows an end view on the inflow side of a particle filter unit of the exhaust gas purification system of FIG. 1, FIG.

3: the particle filter unit of Figure 1 with a different position one of these associated actuator,

4 shows a representation corresponding to that of FIG. 1 with an exhaust gas purification system according to a further embodiment, and FIG

5 shows a representation corresponding to that of FIG. 1 with an exhaust gas purification system according to yet another embodiment.

A diesel engine 1 as a diesel engine has a charge air compressor 3 driven by an exhaust gas turbine 2. The charge air compressor 3 is switched into an air supply line 4, via which the air required for the combustion process is made available to the diesel engine 1. To the manifold 5 of the diesel engine 1 is a generally designated by the reference numeral 6 emission control system connected. The exhaust gas purification system 6 has an exhaust gas line 7, comprising an exhaust gas pipe 8 into which the exhaust gas turbine 2 is switched on, and a particle filter unit 9. The particulate filter unit 9 comprises two filter packages 10, 10.1 in the exemplary embodiment shown. Thus, the particulate filter unit 9 is divided into two filter segments, each filter pack 10 or 10.1 represents such a segment. Both filter packages 10, 10.1 are designed as closed sintered metal filters. The two filter packs 10, 10.1 are separated from each other in the illustrated embodiment by a partition wall 11, whereby the housing 12 enclosing the two filter packs 10, 10.1 is divided into two chambers. In the housing 12 of the particulate filter unit 9 is further arranged a pivoting flap 13 as an actuator, which can be adjusted according to the direction of arrow shown in Figure 1 by an actuator, such as a stepper motor (not shown). In the position shown in Figure 1, the pivoting flap 13 is in a first operating position of the emission control system 6. In this position, the pivoting flap 13, both filter packages 10, 10.1 are supplied by the supplied via the exhaust pipe 8 exhaust gas. The exhaust gas flows through the filter packs 10, 10.1, during which throughflow process in the exhaust gas entrained soot particles are removed from the exhaust gas flow and accumulated on the filter surface. The exhaust gas purification system 6 further comprises a bypass line 15 for generating a secondary flow. In the illustrated embodiment, the bypass duct 15 is designed so that a volumetric flow of about 10% -20% of the exhaust gas flowing through the exhaust pipe 8 can flow through it at full load operation. It is understood that in a non-full load operation of the diesel engine 1, for example, when it is idling, the entire, exhausted from this exhaust gas can be passed through the bypass line 15. For controlling the exhaust gas flow that flows through the bypass duct 15, either as a whole or a part thereof, can be provided by corresponding flow resistances in the exhaust gas duct, which are bridged by the bypass duct 15. This may be, for example, an exhaust gas turbine or an adjustable throttle which is switched into the exhaust pipe 8. It is also possible to integrate a control or timing valve in the bypass line.

The bypass line 15 has on the input side opening into the manifold 5 opening 16. The bypass line 15 serves to supply the diverted from the manifold 5 hot secondary flow into the housing 12 of the particulate filter unit 9, in the flow direction of the exhaust gas before the filter packs 10, 10.1 , For supplying a secondary flow into each chamber of the housing 12 formed by the partition 11, the bypass duct 15 has two duct branches 17, 17.1. Each line branch 17, 17.1 opens into the housing 12 of the particle filter unit 9 of the pivoting flap 13 in the flow direction of the exhaust gas, as can be seen from FIG. In each line branch 17, 17.1 is connected in a manner not shown connected to a control unit control valve 18, 18.1. About the control valves 18, 18.1, the introduced via the respective branch 17 and 17.1 in the particle filter unit 9 bypass flow volume can be controlled.

The filter packs 10, 10.1 are associated with a well-known electric heater for assisting in the initiation of soot oxidation (soot burn-off). The heating device assigned in each case to a filter pack 10 or 10.1 is not shown in FIG. 1 for the sake of clarity. The bypass line 15 may have a branch 19 for exhaust gas recirculation. The branch is shown in dashed lines in Figure 1 only indicated.

Figure 2 shows to illustrate the adjustability of the pivoting flap 13 this in an end view from the viewing direction of the exhaust pipe 8 in a position opposite to the position shown in Figure 1 in the direction of the upstream side of the filter pack 10.1 adjusted position.

In the exemplary embodiment illustrated in FIGS. 1 to 3, the bypass line 15 serves the purpose of supplying thermal energy to support the triggering of a regeneration of the filter packages 10, 10. 1 of the particle filter unit 9. A regeneration of the filter packages 10, 10.1 takes place sequentially. For a filter regeneration, wherein first a regeneration of the filter pack 10.1, as shown in Fig. 3, is provided, the pivoting flap 13 from its position shown in Figure 1 on their position shown in Figure 2 out into their the inflow-side filter surface of the filter pack 10.1 closing position brought. In this position, the pivoting flap 13 abuts against the Anlagewulst 14. In this position, the filter pack 10.1 is not flown by the flowing through the exhaust pipe 8 of the exhaust line 7 main exhaust gas stream. If the filter pack 10.1 is shaded with respect to the main exhaust stream, the control valve 18 of the bypass pipe 15 assigned to the pipe branch 17 is opened. By contrast, the control valve 18.1, which is switched on in the line branch 17.1, remains closed as in the case of the accumulation operation of the particle filter unit 9 of FIG. Via the bypass line 15 then flows from the manifold 5 branched hot exhaust gas into the housing 12 to the upstream surface of the filter pack 10.1. This exhaust gas is about 100 ⁰ C at its entry into the housing 12 of the particulate filter unit 9 warmer than the introduced via the exhaust pipe 8 into the housing 12 main exhaust gas stream. As a result of the shading of the filter pack 10.1 and the supply of this hot secondary exhaust gas stream, the soot accumulated on the upstream surface of the filter pack 10.1 is heated. If the thermal energy supplied with the secondary exhaust gas flow introduced via the bypass duct 15 is insufficient to trigger soot oxidation, the electrical heating device assigned to the filter pack 10.1 is supplied with current. Depending on the design of the exhaust gas purification Supply system and the current temperature conditions, a simultaneous heating of the accumulated on the upstream filter surface of the filter pack 10.1 soot can be made by the supplied hot exhaust gas of the bypass and the simultaneous operation of the electric heater. Accordingly, a faster soot oxidation is triggered and the filter pack 10.1 regenerated.

The regeneration process is controlled with regard to its progress and in particular with regard to its temperature development in the illustrated exemplary embodiment by the exhaust gas secondary flow supplied via the bypass duct 15. Depending on the current operating state of the diesel engine 1, the exhaust gas secondary flow contains a sufficient oxygen content in order to be able to carry out soot oxidation as intended. Thus, via the bypass line 15, the oxygen required for the soot oxidation is supplied in the form of the residual oxygen contained in the exhaust gas. The progress of the soot oxidation on the filter surface of the filter pack 10.1 is detected in the illustrated embodiment via a temperature sensor integrated in the filter pack 10.1 and evaluated in a control unit (not shown in the figures). In order to avoid damage to the particulate filter unit 9 as a result of overheating in the soot oxidation, the supply of the supplied via the bypass line 15 side stream is reduced by appropriate control of the control valve 18 when the current temperature on the filter pack 10.1 has exceeded a certain threshold. As a result of the reduction in the exhaust gas secondary flow volume supplied, correspondingly less oxygen is made available to the oxidizing soot, with the result that the soot oxidation is slowed down and consequently less exothermic energy is released.

To control the soot oxidation can be used in addition to the control valve 18 and 18.1 as another actuator, the pivoting flap 13. If the pivoting flap 13 is opened from its position shown in FIG. 3 completely shading with respect to the main exhaust gas flow, the filter packet 10.1 is supplied with a relatively cool main exhaust gas stream from part of the exhaust gas leaving the bypass flow line 15 with respect to the temperature the permeability of the filter pack 10.1 excess heat removed. The adjusting Members - the control valves 18, 18.1 and the pivoting flap 13 - are connected to their control to a control device. A soot oxidation on the filter pack 10. 1 can then be optimally regulated in accordance with the respective conditions by changing the supplied sidestream exhaust gas volume flow and the main exhaust gas stream which is cooler relative to it.

During the process of regeneration of the filter pack 10.1, the filter pack 10 still flows through the exhaust gas. If the typically only a few minutes continuous regeneration process on the filter pack 10.1 completed, the pivoting flap 13 is adjusted to shadow the filter pack 10. In this position, the pivoting flap 13 flows through the exhaust pipe 8 supplied exhaust gas of the main exhaust stream, the regenerated filter pack 10.1. For regeneration of the filter pack 10, the control valve 17 is closed and the control valve 17.1 opened. The regeneration of the filter pack 10 takes place in the same way as described for the filter pack 10.1.

FIG. 4 shows the diesel engine 1, to whose elbow 5 an exhaust gas purification system 6.1 according to a further exemplary embodiment is connected. Basically, the exhaust gas purification system 6.1 is designed as described for the figures 1 to 3. In contrast to the emission control system 6 of Figures 1 to 3, the filter packs 10, 10.1 do not have additional electrical heating elements. The exhaust gas purification system 6.1 differs from the exhaust gas purification system 6 in that in the bypass line 15 of the division of the line branches 17, 17.1 upstream of a burner 20 is switched on to heat the flowing over the bypass line 15 exhaust gas secondary flow. The burner 20 is designed as a flame burner, operates fuel-powered and is connected in a manner not shown to the fuel tank for the diesel engine 1 and a control device. Through the burner 20, the bypass exhaust gas can be brought to a higher temperature level in order to be able to supply the filter pack 10 or 10.1 more thermal energy. In the illustrated embodiment, the burner 20, an oxidation catalyst 21 is connected downstream. By over-injecting the burner 20, ie by supplying such an amount of fuel that does not completely burn it, fuel can be injected onto the fuel catalytic surface of the oxidation catalyst 21 are brought, wherein the HC compounds are split in an exothermic reaction. In this embodiment, the burner 20 is used to bring the oxidation catalyst 21 to its operating temperature in order to give the bypass flow flowing through the bypass by injecting fuel through the burner 20 on the oxidation catalyst 21 the necessary temperature. In this refinement, the secondary flow flowing into the housing 12 of the particle filter unit 9 can have a temperature which is sufficient for triggering soot burn-off without additional additional measures. A regulation of Rußabbrandes takes place in an analogous manner, as described for the embodiment of Figures 1 to 3.

FIG. 5 shows a further exhaust gas purification system 6.2, which is connected to the diesel engine 1. The bypass duct 15 is designed in this embodiment, as described for the exhaust gas purification system 6.1 of Figure 4. In addition to the particulate filter unit 9, the exhaust gas purification system 6.2 has an SCR catalytic converter, which can be designed, for example, as a coating on the filter clean side of the filter packs 10, 10.1. For this purpose, the emission control system 6.2 of the combined particulate filter SCR unit has a urea supply device 22. This comprises a storage container 23 for storing aqueous urea solution as a so-called precursor for the reducing agent NH ₃ contained therein. This is the output side connected to a disposed within the exhaust pipe 8 mixing tube 24 with the interposition of a metering valve, not shown. The mixing tube 24 serves to atomize the aqueous urea solution. For this purpose, a sputtering gas is needed. In the exhaust gas purification system 6.2, exhaust gas from the exhaust gas bypass stream flowing via the bypass line 15 is used as the atomizing gas. For this purpose, the bypass duct 15 has a branch 25 for supplying Nebenstromab- gas to the mixing tube 24. In the branch 25 is turned on a valve 26 for controlling the inflow of the exhaust gas secondary flow to the mixing tube 24. The urea supply means 22 is supplied at this Out Design of hot, branched off from the manifold 5 of the diesel engine 1 exhaust gas, whereby the thermolytic decomposition of the metered aqueous urea solution for releasing the ammonia contained therein (NH ₃ ) in the Mixing tube 24 and in which adjoins the mixing tube 24 in the flow direction of the exhaust gas portion of the exhaust pipe 8 performs correspondingly faster compared with a configuration in which is used at ambient temperature air for the desired urea solution atomization.

Instead of or in addition to the branch 25, a connecting line between the line branch 17.1 and the branch 25 may be provided in order to supply heated exhaust gas for atomization of supplied urea solution into the mixing tube 24 through the burner 20 or the oxidation catalyst 21. In this, designated by the reference numeral 27 in Figure 5 line a valve 28 is turned on. Figure 5 shows both of the above-described embodiments in the exhaust gas purification system 6.2, wherein it is understood to one skilled in the art, even one of these two ways for supplying heat used in the mixing tube or an exhaust system can be equipped with only one of these two pathways for supplying heat ,

To minimize temperature losses in the bypass duct 15 by dissipating heat to the environment, the bypass duct may have thermal insulation. This can be useful if no heating unit is switched on in the bypass line.

In addition to the particulate filter units described, the described exhaust gas purification system and the described method are equally suitable if other filter packs are arranged together in one housing or filter packs in different housings. In addition, further, a filter regeneration triggering measures may be incorporated in such an emission control system, for example by implementing measures for lowering the Rußoxidati- onstemperatur.

The described exhaust gas purification systems and the described method can basically be operated as autonomous units without it being absolutely necessary to have to obtain and evaluate data from the engine management via a corresponding interface. Therefore, such an emission control system is particularly suitable for retrofit solutions.

LIST OF REFERENCE NUMBERS

1 diesel engine

2 exhaust gas turbine

3 charge air compressor

4 air supply line

5 Manifold, 6.1, 6.2 Emission control system

7 exhaust system

8 exhaust pipe

9 Particle filter unit 10, 10.1 Filter package

11 partition

12 housing

13 swing flap

14 Anlagewulst

15 bypass line

16 opening

17, 17.1 conductor branch

18, 18.1 control valve

19 branch

20 burners

21 oxidation catalyst

22 urea supply device

23 storage tank

24 mixing tube

25 branch

26 valve

27 line

28 valve

Claims

claims

1. exhaust gas purification system, in particular for a Dieselbrennkraft- machine (1), comprising at least one in the exhaust line (7) switched on exhaust gas cleaning unit (9) and means for supplying thermal energy into the exhaust line (7) for triggering and / or supporting a in In connection with the exhaust gas cleaning process, which device comprises a to the exhaust line (7) parallel extending bypass line (15) from which bypass line (15) due to their arrangement to the exhaust line (7) and / or by a heating unit switched on the output side exhaust gas in a relative to the exhaust gas temperature in the exhaust line (7) higher temperature to the exhaust line (7) can be fed and which bypass line (15) outputs on the output side for supplying thermal energy in the exhaust line (7) at or in the region of that exhaust line section, in which the thermal energy is required, characterized in that in the exhaust line (7 ) is arranged as an exhaust gas purification unit a particulate filter unit (9) with at least one provided by the particulate filter unit (9) filter surface actuator (13) for blocking and / or reducing the exhaust gas supply from the exhaust line (7) in at least one segment (10, 10.1) and that the outlet-side mouth of the bypass line (15, 17, 17.1) downstream of the actuator (13) and the filter surface is connected upstream.

2. Emission control system according to claim 1, characterized in that actuator is a pivotally mounted flap (13).

3. The exhaust gas purification system according to claim 1, characterized in that the filter surface upstream of the actuator for covering one or more segments (10 or 10.1) of

Filter surface provided, preferably rotatably mounted relative to the filter surface aperture is.

4. Emission control system according to one of claims 1 to 3, characterized in that the filter segments (10, 10.1) are assigned to support the triggering of soot oxidation in each case one or more electrical heating elements.

5. Emission control system according to one of claims 1 to 4, characterized in that in the bypass line (15) a burner (20) is arranged as a heating unit for increasing the temperature of the exhaust gas flowing in the bypass line (15).

6. Emission control system according to claim 5, characterized in that a flame burner is provided as the burner (20).

7. An exhaust gas purification system according to claim 6, characterized in that the flame burner (20) is a Oxidationskatalysa- tor (21) connected downstream.

8. The exhaust gas purification system according to claim 5, characterized in that the burner is designed as a catalytic burner.

9. exhaust gas purification system according to one of claims 1 to 8, characterized in that the exhaust gas purification system (6.2) comprises a urea supply means (22) for supplying liquid urea in the exhaust line (7) and the bypass line (15) for supporting the urea processing in the exhaust line in this opens.

10. An exhaust gas purification system according to claim 9, characterized in that the bypass line (15) in one of the urea supply means (22) associated, in the exhaust line (7) arranged arranged mixing tube (24) opens.

11. Method for supplying thermal energy for triggering and / or supporting a running in an emission control system (6, 6.1, 6.2), in particular a diesel engine (1) process, wherein a portion of the engine side exhaust discharged from the exhaust stream as a side stream and introduced at the point in the exhaust line (7) again is required at the thermal energy for triggering and / or supporting a process related to the exhaust gas purification, this process is a regeneration of a particulate filter unit (9) and the exhaust gas supplied via the side stream a higher temperature than that exhaust gas not flowing through the side stream, characterized in that the particulate filter unit (9) is subject to regeneration in segments and the secondary exhaust gas upstream of a segment (10, 10.1) of the particulate filter for triggering and separated by an actuator (13) from the main exhaust stream / or supporting a carbon black oxide ion in this segment (10, 10.1) is supplied.

12. The method according to claim 11, characterized in that after initiation of the soot oxidation process, the Rußoxidations- process is observed in terms of its progress and depending on at least one parameter detected in this regard, such as the temperature, the amount of oxygen supplied to the filter surface by changing the Volume flow of the exhaust gas supplied from the bypass flow and / or by changing the supply of exhaust gas from the main exhaust gas flow is changed in the regenerated segment.