DE102010037293A1 - Method for operating exhaust gas burner at output of combustion chamber of internal combustion engine, particularly diesel engine, pressurizing combustion chamber of burner by generating exhaust gas pressure in exhaust section - Google Patents

Abstract

The method involves generating a fuel-air mixture in a combustion chamber with specific mixture ratio over a cross section of inhomogeneous distribution of areas. A burner (11) is operated with an operation of a combustion engine (2) for conducting thermal energy into an exhaust section (4). The exhaust gas pressure, generated in the exhaust section by the operation of the combustion engine, pressurizes the combustion chamber of the burner. An independent claim is also included for an emission control system for an internal combustion engine, particularly for a diesel engine.

Description

The invention relates to a method for operating a with the output of its combustion chamber to the exhaust system of an internal combustion engine, in particular a diesel engine for supplying thermal energy in the exhaust system connected burner. Furthermore, the invention relates to exhaust gas purification system for an internal combustion engine, in particular a diesel engine, with an exhaust system, with at least one switched on in the exhaust gas emission control unit and a burner for supplying thermal energy into the exhaust line for triggering and / or supporting an exhaust gas purification process, the combustion chamber exit in the flow direction the exhaust gas upstream of the exhaust gas purification unit opens into the exhaust system.

For cleaning the exhaust gases emitted by an internal combustion engine, such as a diesel engine, it may be necessary for the exhaust gas or the exhaust gas purification unit to have a certain minimum temperature. In order to perform such an exhaust aftertreatment process even when the exhaust gas and thus the exhaust gas purification unit does not yet have the minimum temperature, the exhaust gas is sometimes heated by additional measures, such as by switching on an exhaust gas burner.

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 soot entrained in the exhaust gas, a particulate filter can be switched on in the exhaust gas line. On the upstream surface of the particulate filter accumulates in the exhaust soot accumulates. So that in the course of successive Rußakkumulation the exhaust back pressure does not rise too far and 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 engine, the necessary temperature for triggering Rußabbrandes is not always achieved by the inflowing exhaust gas, it is necessary in such cases, otherwise to supply thermal energy for triggering a regeneration process. This is done either by heating the filter body or its upstream surface by means of electrical heating elements or by heating the exhaust gas flowing to the filter by using burners and / or oxidation catalysts, which are fueled to increase the exhaust gas temperature.

If a denitrification of the exhaust gas is desired, SCR catalysts (Selective Catalytic Reduction) are switched on in the exhaust system. For a SCR process, a reducing agent is needed. The reducing agent used is ammonia. This is typically injected in the form of an aqueous urea solution, upstream of the SCR catalytic converter, into the exhaust gas line. Care must be taken to ensure that the urea solution added to the exhaust gas stream has been thermolytically split before reaching the SCR catalyst to release the ammonia contained therein. A thermolytic splitting of the supplied urea solution takes place in the temperature of the exhaust gas stream, so that only a sufficient flow path between the location of the urea injection and the SCR catalyst must be present. For urea treatment within the exhaust stream mixing tubes are used, in which ambient air is supplied to assist a sputtering process of the urea solution. To further support the urea processing within the exhaust stream this can be supplied heated. For this purpose, however, additional heat sources are necessary.

Out DE 10 2005 054 733 A1 a burner for catalyst heating with controlled or regulated fuel supply is described. In this prior art emission control system, the burner is supplied with ambient air provided by an electrically operated compressor. An air mass meter is used to detect the air supplied to the burner. In this burner is provided to regulate the fuel supply, in response to the burner air supplied. This is supplied to the burner at a constant rate according to an embodiment. In the foreground of the burner which became known from this document is an operation of the same with a predetermined fuel-air mixing ratio. To control the same can be turned on in the exhaust stream of the burner, a lambda probe.

The operation of this prior art burner with a predetermined fuel-air mixture ratio is carried out against the background that this is operated to achieve optimum performance under the optimum conditions for its operation. It is therefore necessary in this burner, to provide by controlling the air supply into its combustion chamber, the most optimal fuel-air mixture ratio. So that an air supply even with a load operation of Internal combustion engine can be ensured, measures must be taken so that even with the then higher exhaust gas pressure in the exhaust line necessary for the operation of the burner ambient air is supplied with sufficient volume. This is only possible with compressors.

As an alternative to burners of the aforementioned type with their greater control and regulation effort including a complex air supply exhaust gas burners are known for the purpose of regeneration of particulate filters, which are operated only during a motor stall. Then it is possible to supply the necessary for the operation of the burner air by means of a fan, such as a fan or fan. However, a use of such regeneration burners is not suitable for dynamic operation, since then there is the danger that extinguished at a corresponding exhaust pressure in the exhaust line of the burner.

Based on this discussed prior art, the present invention seeks to propose a method for operating an exhaust gas burner, which in principle without special control and / or control effort and without the need for the use of a compressor for supplying the necessary for the operation of the burner air in an operation of the internal combustion engine, in particular also a dynamic operation of the internal combustion engine manages. Likewise, the invention has the object of developing an aforementioned, generic emission control system in this sense.

The method-related object is achieved by an aforementioned, generic method in which in the combustion chamber, a fuel-air mixture is produced with an inhomogeneous over the cross section of the same inhomogeneous distribution of areas with the same mixing ratio and in which the burner for supplying thermal Energy is operated in the exhaust system during operation of the internal combustion engine, so that the exhaust gas pressure generated by the operation of the internal combustion engine in the exhaust gas line acts on the combustion chamber of the burner.

The object directed to the exhaust gas purification system is achieved by an exhaust gas cleaning system with the preamble of claim 9, wherein the burner has a combustion chamber, in the longitudinal axial direction thereof a fuel supply and an air supply from each other open, wherein the air supply to the outlet of the combustion chamber is closer as the fuel supply, and that between the fuel supply and the air supply one or more air-directing internals for directing the air flow supplied during operation of the burner in a flowing in the direction of the combustion chamber portion with the fuel supply partial airflow and a flowing away from the combustion chamber portion with the fuel supply partial airflow.

Both in the claimed method and in the claimed emission control system is in the foreground to achieve an inhomogeneous distribution with respect to the mixing ratio of the fuel-air mixture within the combustion chamber of the exhaust gas burner. The inhomogeneous distribution takes place largely in relation to the free cross-sectional area of the combustion chamber. It has been found that when such an inhomogeneous distribution of the fuel-air mixture is present within the combustion chamber, during operation of the burner of the burner flame always such fuel-air mixing ratio ranges are available that for a current operating situation of the burner at an operation of the internal combustion engine and thus is required when flowing through the exhaust gas exhaust. Thus, an operation of this burner takes place in departure from the previous teaching for the operation of exhaust gas burners, within the combustion chamber for the best possible operation of the burner, seen over the cross section of the combustion chamber to provide a homogeneous fuel-air mixture ratio within the combustion chamber. In the subject matter of the claimed invention, the operation of the internal combustion engine, in particular a dynamic operation of the same supports the formation of the desired inhomogeneous distribution of regions with the same mixing ratio within the combustion chamber of the burner. The burner is connected with its output to the exhaust system. Therefore, the combustion chamber is acted upon by the pressure located in the exhaust line. As a result of the above-described inhomogeneous distribution of fuel-air mixture ratio ranges within the combustion chamber, there is no risk that the burner flame will extinguish when the load operation of the internal combustion engine increases as a result of the exhaust gas pressure higher in the exhaust gas line. In the subject matter of the claimed method, as well as in the claimed exhaust gas purifying system, such operation results in migration of the flame to an area where the fuel-air mixing ratio suitable for the combustion process is located. When the pressure in the exhaust line is increased, the burner flame is forced into the burner. At a pressure drop, the burner flame moves in the other direction due to the then lower back pressure. It has been found that for the purposes of using such an exhaust gas burner, contrary to expectations, it is not necessary for conditions within the combustion chamber which are as optimal as possible to ensure a uniform distribution of the fuel gas extending over the cross-sectional area of the combustion chamber. Air mixture must be given to operate the burner. Rather, it is quite sufficient to have sub-optimal fuel-air mixture ratio distribution conditions. It was surprising to note that the method described and the exhaust gas cleaning system described ensure operation of the burner even during dynamic operation of the internal combustion engine.

Such a burner needs in front of the above-described background for its air supply only a fan or fan, since in contrast to the prior art in the subject of the claimed invention is not trying within the entire combustion chamber as optimal as possible air-fuel mixing ratio for the operation of the Brenners ready. It has been shown that in the described concept, the operating window for operating the burner is unexpectedly large, that is: The burner can be operated for the purpose of supplying thermal energy into the exhaust system quasi at any operating condition of the internal combustion engine. Thus, the subject of the invention is not only suitable for an intermittent operation, such as the supply of thermal energy for triggering a regeneration process on a particulate filter, but also for a prolonged operation, for example, for supplying thermal energy to an SCR catalyst to this to bring it to its operating temperature faster.

Particularly good results are achieved with a burner operating method, if within the combustion chamber, the fuel-air mixture is generated with a course of its lines equal mixing ratio, so that they have at least one off-center, bulging towards the outlet of the combustion chamber extending bulge. As a result of the at least one bulge, which may be an annular bulge, approximately concentric with the longitudinal axis of the combustion chamber, the burner flame can easily reach different mixing ratio ranges and thus easily - as described above - migrate. In a fundamental change of the fuel-air mixture ratio within this combustion chamber, the image of the presence of a bulging of the lines of equal mixing ratio extending in the direction of the output is maintained. If the pressure in the exhaust line changes, this forces the burner flame into the burner. The burner works with a certain amount of air. Due to the above-described inhomogeneous fuel-air mixture distribution within the burner chamber, however, mixing ratios are also to be found in these areas, which keep the burner flame from burning. In the reverse case of a pressure drop in the exhaust line, the burner flame tends to migrate towards the output of the burner. This basically results in operation of the burner with excess air. Even with such a constellation, it becomes clear that the above-described inhomogeneous distribution of the fuel-air mixture, expressed by the course of the lines of equal mixing ratio, does not cause the burner flame to go out, since these ultimately gain access to one for their operation, regardless of their position within the combustion chamber suitable fuel-air mixture ratio has.

For generating such an inhomogeneous distribution of fuel-air mixture ratio ranges within the combustion chamber, it is provided according to an embodiment that the fuel supply and the air supply are spaced apart in the longitudinal axial extent of the combustion chamber. It is provided that the air supply to the output of the combustion chamber is closer than the fuel supply. Particularly useful is an embodiment in which the air supply is divided in the combustion chamber, in such a way that a partial air flow flows in the direction of the fuel supply and another partial air flow in the direction of the fuel supply away. In such an embodiment, the partial air flow directed to the fuel supply or into the combustion chamber section with the fuel supply is typically smaller than the other partial air flow and amounts, for example, to 10 to 25% of the supplied air volume. Such air flow splitting is effected, for example, by one or more air-directing internals within the combustion chamber, typically adjacent to the mouth of the air supply in the combustion chamber. As air-guiding installation can be provided adjacent to the mouth of the air supply and shading the fuel supply wall.

According to a further embodiment, in order to support the inhomogeneous distribution of regions of the same fuel-air mixture ratio within the combustion chamber in a dynamic operation of the internal combustion engine, it is provided to arrange a diaphragm in the region of the output of the combustion chamber. This can for example be designed as a pinhole, for example, with a central opening, which is provided in a development that such a central opening is surrounded by a plurality of openings. Such a diaphragm supports the formation of line-like mixing ratio within the combustion chamber, as described above, since then the combustion chamber is acted upon unevenly over the cross section of the combustion chamber by the pressure prevailing in the exhaust gas line.

Further advantages and embodiments of the invention will become apparent from the following description of embodiments with reference to the accompanying figures. Show it:

1 In a schematic representation in the manner of a block diagram of a diesel engine with an exhaust gas purification system connected thereto, comprising an exhaust gas burner,

2 : A longitudinal section through the exhaust gas burner of the emission control system 1 .

3 : A schematic representation of the burner of the 2 with lines of the same fuel-air mixture ratio within its combustion chamber at a first operating state of the burner,

4 : A representation corresponding to that of 3 during operation of the burner with high excess air,

5 FIG. 2: A representation of a burner with a homogeneous fuel-air mixture distribution in its combustion chamber according to the prior art, FIG.

6 : A schematic cross section through the combustion chamber of the burner 2 with a wall between the air supply and the fuel supply according to a first embodiment,

7 : A representation corresponding to that of 6 with a wall between the air supply and the fuel supply according to a further embodiment and

8th : A representation corresponding to that of 6 and 7 with a wall between the air supply and the fuel supply to the combustion chamber of the burner according to yet another embodiment.

To the exhaust manifold 1 a diesel engine 2 an otherwise not shown vehicle is an emission control system 3 connected. The emission control system 3 has an exhaust gas system 4 in the exhaust gas purification unit in the illustrated embodiment, a particulate filter 5 as well as the particle filter 5 upstream oxidation catalyst 6 are turned on. The particle filter 5 and the oxidation catalyst 6 are together in one housing 7 arranged. It can be provided that the housing 7 between the oxidation catalyst 6 and the particulate filter 5 an interface for opening the housing 7 having. This serves the purpose, if necessary, to the upstream surface of the particulate filter 5 to be able to remove, for example, ashes residue. The housing 7 has an inlet cone 8th into the exhaust pipe 9 the exhaust line 4 empties.

In the illustrated embodiment opens into the input cone 8th of the housing 7 at the mouth of the exhaust pipe 9 opposite side another pipe 10 , This is the exhaust pipe of a burner 11 , The burner 11 serves to supply thermal energy into the exhaust system 4 , in particular for supplying thermal energy for the purpose of regeneration of the particulate filter 5 ,

At the burner 11 it is a fuel burner. This is connected to a fuel supply line 12 into which a metering pump 13 is switched on for metering the fuel supply. Connected to the burner 11 is further an air supply line 14 , In the manner not shown by a fan to the operation of the burner 11 required air is conveyed into the combustion chamber of the same. The dosing pump 13 is to a control unit 15 connected.

2 shows the burner 11 in a more detailed representation in a longitudinal section. The total with the reference number 16 designated combustion chamber of the burner 11 is in a rear combustion chamber section 17 and a front combustor section 18 divided. Separate the two combustion chamber sections 17 . 18 through one in the upper part of the combustion chamber 16 located wall 19 , The for the operation of the burner 11 supplied ambient air enters by means of a tangential into the combustion chamber 16 or the combustion chamber section 18 arranged pipe 20 one. The pipe 20 passes through the cylindrical burner tube 21 and ends with its other end in a burner tube 21 surrounding annular chamber 22 , In this opens into an air intake opening 23 the air supply line 14 , When operating the burner 11 is then on the outer wall of the burner tube 21 the supplied ambient air before entering the combustion chamber section 18 heated. At the same time, during operation of the burner 11 the burner tube 21 cooled by this measure. The fuel supply line 12 opens into a total with the reference numeral 24 characterized fuel supply, whose output in the rear combustion chamber section 17 is arranged. The output of the fuel supply 24 is from the exit of the pipe 20 for the air supply through the at the top of the combustion chamber 16 arranged wall 19 shadowed. The fuel supply further comprises a glow plug for igniting the burner 11 ,

In the area of the exit of the combustion chamber 16 there is an aperture 25 that at the illustrated embodiment is designed as a pinhole.

During operation of the burner 11 forms inside the combustion chamber 18 an inhomogeneous distribution of areas of the same air-fuel ratio, as this in 3 can be seen on the basis of the lines registered therein the same fuel-air mixture ratio. The in 3 shown line curve represents a first operating situation of the burner 11 dar. From the direction of the rear combustion chamber section 17 towards the front combustion chamber section 18 and the aperture 25 The illustrated lines each show mixing ratios with an increasing proportion of air relative to the fuel portion. Due to the tangential introduction of the air required for the combustion process through the pipe 20 arises within the combustion chamber 16 a swirl flow, which is why approximately concentric to the longitudinal axis of the combustion chamber 16 an annular bulge 26 in the image of the lines shows the same air-fuel ratio. About the cross section of the front combustion chamber section 18 seen in which combustion chamber section 18 the flame during operation of the burner 11 is, it can be seen that increases in the radial direction from outside to inside the mixing ratio in favor of the fuel content. Because of the bulge 26 is in each case a maximum of the fuel portion in the fuel-air mixture ratio in the center of the bulge 26 , Between the annular bulge 26 The proportion of fuel within the mixing ratio decreases again slightly. Characteristic is the closely spaced sections of quasi-parallel course of the lines of equal mixing ratios to the inner wall of the Brennkammerabschnites 18 , This narrow course of the lines shows a high rate of change of the mixing ratio over a short distance and makes it clear that the burner flame can easily fall back on different fuel-air mixing ratios.

Is schematized in 4 shown the inhomogeneous distribution of areas with the same fuel-air mixture ratio, but in contrast to the representation of 3 during operation of the burner 11 with high excess air. It is clearly evident that even with such operation of the burner 11 into the combustion chamber 18 in the form of a from the rear combustion chamber section 17 in the front combustion chamber section 18 expanding bulge 26.1 an area with a fuel-air mixing ratio is possible, in which the flame of the burner 11 still burning. A state of operation of the burner 11 , as in 4 can be shown briefly during dynamic operation of the diesel engine 2 occur, especially with pulsating exhaust gas pressure, from the representation of the 4 it becomes clear that even under such conditions the flame does not go out. This is especially true against the background that for the operation of the burner 11 supplied air is supplied with a low-energy blower and not a compressor. In the subject matter of this exhaust gas burner or in the method used for operating the same, it is not necessary, in contrast to previously known burners, to encounter a higher exhaust backpressure through appropriate air supply measures, for example by means of a compressor or the like.

In 5 is to illustrate the term used in the context of these statements "inhomogeneous distribution" of areas with the same mixing ratio within the combustion chamber, a combustion chamber 16.1 a burner 11.1 shown in the prior art. The lines of equal air-fuel ratio are more or less convex to the output of the burner 11.1 arched and are stretched over the entire cross-section. The fuel-air mixture distribution in a combustion chamber with lines equal mixing ratio, as in 5 is to be addressed as a homogeneous fuel-air mixture distribution. The difference to the fuel-air mixture distribution according to the described invention is obvious, especially by the absence of an eccentric bulge and the extension of the lines of the same air-fuel ratio, at least in sections parallel or quasi parallel to the inner wall of the combustion chamber 16 ,

6 to 8th show different designs to the over the pipe 20 into the combustion chamber 16 or the front combustion chamber section 18 to divide supplied airflow. According to the embodiment of 6 that of the design, as in 2 shown corresponds to, is located in the upper region of the combustion chamber 16 the wall 19 , The wall 19 shadows the fuel supply 24 from the air supply. the wall 19 has a height that is about the diameter of the tube 20 equivalent. A division of the supplied air flow takes place in the on the inner wall 27 the combustion chamber 16 bordering section 28 the Wall 19 in which area a portion of the supplied airflow over the wall 19 in the rear combustion chamber section 17 flows. 7 shows an alternative embodiment in which the through the pipe 20.1 supplied airflow shading wall 19.1 sickle-shaped. In the embodiment according to 7 is the entering into the rear combustion chamber portion of the partial air flow less than in the embodiment of 6 , Yet another embodiment of a wall 19.2 is in 8th shown. The wall shown in this embodiment 19.2 is designed as a perforated plate, with the mouth of the tube 20.2 inside the front Combustion chamber portion is arranged next to an unperforated area. That's the wall 19.2 forming perforated plate has a total of three large openings.

The walls 19 . 19.1 . 19.2 support the formation of an inhomogeneous fuel-air mixture distribution in the combustion chamber of the respective burner.

For a person skilled in the art will arise from the description of the invention and its illustrations in the embodiments described above numerous other ways to generate based on the claimed invention an inhomogeneous distribution of areas with the same fuel-air mixture ratio, without this would have to be described in detail ,

LIST OF REFERENCE NUMBERS

1

exhaust manifold

2

diesel engine

3

emission control system

4

exhaust gas line

5

particulate Filter

6

oxidation catalyst

7

casing

8th

inlet cone

9

exhaust pipe

10

pipe

11, 11.1

burner

12

fuel supply

13

metering

14

air supply line

15

control unit

16, 16.1

combustion chamber

17

rear combustion chamber section

18

front combustion chamber section

19, 19.1, 19.2

wall

20, 20.1, 20.2

pipe

21

burner tube

22

annular chamber

23

Air inlet opening

24

Fuel supply

25

cover

26, 26.1

bulge

27

inner wall

28

section

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102005054733 A1 [0005]

Claims (12)

Method for operating one with the output of its combustion chamber ( 16 ) to the exhaust gas line ( 4 ) an internal combustion engine, in particular a diesel engine ( 2 ) for supplying thermal energy into the exhaust line ( 4 ) connected burner ( 11 ), characterized in that in the combustion chamber ( 16 ) a fuel-air mixture is produced with an inhomogeneous distribution, seen over the cross section thereof, of regions with the same mixing ratio, and in that the burner ( 11 ) for supplying thermal energy into the exhaust line ( 4 ) during operation of the internal combustion engine ( 2 ) is operated so that by the operation of the internal combustion engine ( 2 ) exhaust gas pressure generated in the exhaust system, the combustion chamber ( 16 ) of the burner ( 11 ). Method according to claim 1, characterized in that within the combustion chamber ( 16 ) a fuel-air mixture is generated with a course of its lines of equal mixing ratio, so that these at least one eccentrically arranged, toward the exit of the combustion chamber ( 16 ) extending bulge ( 26 . 26.1 ) exhibit. Method according to claim 1 or 2, characterized in that the burner ( 11 ) the oxygen necessary for its operation is supplied by a ventilated by means of a fan ambient air flow. Method according to one of claims 1 to 3, characterized in that the burner ( 11 ) during a dynamic operation of the internal combustion engine ( 2 ) is operated so that by the consequent pulsation of the pressure in the exhaust line ( 4 ) the formation of the inhomogeneous distribution of regions with the same mixing ratio in the combustion chamber ( 16 ) is supported. Method according to one of claims 1 to 4, characterized in that for the operation of the burner ( 11 ) required air in the longitudinal axial extent of the combustion chamber ( 16 ) from the fuel supply ( 24 ) is supplied spaced, closer to the output of the combustion chamber ( 16 ). Method according to claim 5, characterized in that the air supply in the combustion chamber ( 16 ) so that a partial air flow towards the fuel supply ( 24 ) and a further partial air flow in the direction of the fuel supply away in the combustion chamber ( 16 ) flows in. A method according to claim 6, characterized in that the air supply division is uneven, wherein the fuel supply ( 24 ) Partial air flow is smaller in volume than the other part of the air flow. Method according to one of claims 1 to 7, characterized in that an admission of the combustion chamber ( 16 ) of the burner ( 11 ) is uneven across the cross section of its opening width due to the exhaust gas pressure prevailing in the exhaust gas line. Exhaust gas purification system for an internal combustion engine, in particular a diesel engine ( 2 ), with an exhaust gas line ( 4 ), with at least one in the exhaust line ( 4 ) switched on emission control unit ( 5 . 6 ) and with a burner ( 11 ) for supplying thermal energy into the exhaust line ( 4 ) for triggering and / or supporting an exhaust gas purification process, whose combustion chamber outlet in the flow direction of the exhaust gas reaches the exhaust gas purification unit ( 5 . 6 ) upstream in the exhaust line ( 4 ), characterized in that the burner ( 11 ) a combustion chamber ( 16 ), in which in the longitudinal axial direction thereof a fuel supply ( 24 ) and an air supply ( 20 ) spaced apart, the air supply ( 20 ) the output of the combustion chamber ( 16 ) is closer than the fuel supply ( 24 ), and that between the fuel supply ( 24 ) and the air supply ( 20 ) one or more air-steering internals ( 19 . 19.1 . 19.2 ) for steering the burner during operation ( 11 ) in a direction towards the combustion chamber section ( 17 ) with the fuel supply ( 24 ) and a part of the combustion chamber ( 17 ) with the fuel supply ( 24 ) flowing away partial air flow. Exhaust gas purification system according to claim 9, characterized in that as air-guiding installation adjacent to the mouth of the air supply ( 20 ) one the fuel supply ( 24 ) shading wall ( 19 . 19.1 . 19.2 ) is provided. Emission control system according to claim 10, characterized in that the wall ( 19.2 ) Part of a cross section of the combustion chamber ( 16 ) extending perforated plate, wherein adjacent to the mouth of the air supply ( 20 ) A closed region of the perforated plate is arranged. Exhaust gas purification system according to one of claims 9 to 11, characterized in that in the region of the outlet of the combustion chamber ( 16 ) an aperture ( 25 ), in particular a diaphragm with one or more holes is arranged.

Images