DE102012103695A1 - Exhaust gas after treatment device for use in both passenger cars and commercial vehicles, has urea-water channel with gas collecting pocket, in which gas, promoting in one direction by pump, is set under pressure - Google Patents

Abstract

The exhaust gas after treatment device has a control unit (53) for controlling a pump (2) in two opposite directions, where the pump promotes a urea-water solution from a tank (1) to a nozzle (70) by the urea-water channel (57) in a direction (20), where the nozzle injects the urea-water solution in an exhaust stream (18). The urea-water channel has a gas collecting pocket (56) between the nozzle and the pump, where a gas, promoting in the direction by the pump, is set under pressure in the gas collecting pocket. An independent claim is included for a method for exhaust gas after treatment.

Description

The invention relates according to the one-part claim 1 an exhaust gas aftertreatment device. According to the independent method claim 14, the invention relates to a method for an exhaust gas aftertreatment device.

Hereinafter, urea-water solution is referred to as HWL.

From the WO 2009/010569 A1 and the DE 10 2009 037 564 A1 In each case an exhaust aftertreatment device with a pump is known, which can pump in two directions. In the first direction, the pump delivers a HWL from a tank through a HWL channel to a nozzle that injects the HWL into an exhaust stream. In the second direction, HWL is conveyed back into the tank. In the WO 2009/010569 A1 addresses the problem that HWL tends to freeze quickly. This freezing increases the pressure of the HWL transitioning to the solid state. To reduce the pressure in time, a pressure relief device is proposed, which includes a 2/2-way valve, which goes off the HWL channel.

From the US 2009/0205316 For example, an exhaust aftertreatment device with a pump is known. This pump conveys a HWL from a tank through a HWL duct to a nozzle that injects the HWL into an exhaust stream. From the HWL channel goes from a calibrated check valve, which acts as a control valve and controls the "spray pressure" in the HWL channel.

The not pre-published DE 10 2011 053 742.2 relates to a heat exchanger for a metering unit of an exhaust gas aftertreatment device.

The object of the invention is to provide an exhaust gas aftertreatment device which is reliably freeze-protected even without a power supply.

This object is achieved with the features of claim 1 and 14.

The invention can be found both in passenger cars and commercial vehicles application, since the exhaust gas aftertreatment device according to the invention requires no compressed air. Such other "air-assisted systems" with compressed air are used in commercially available commercial vehicles for injecting the HWL into the exhaust gas system.

Commercial vehicles are often sold with the "emergency stop button" prescribed for transporting dangerous goods, which separates the entire vehicle electrical system from the power supply. Without power supply, however, there is the problem that the exhaust aftertreatment device can not be pumped from the pump, so that in cold weather freezing HWL destroys the exhaust aftertreatment device more and more with each freezing cycle.

• – beim Einschalten des Bordnetzes über den Zündschlüssel oder
• – beim Einschalten des Bordnetzes über eine „schlüssellos-Zugangskarte” oder
• – beim Motorstart

– d. h. zur Betriebsstartphase – von der „rückwärts” laufenden Pumpe Gas in den HWL-Kanal eingesaugt wird. Dies erfolgt für eine begrenzte Zeit, wie beispielsweise 10 Sekunden. Im Anschluss wird die Pumpe wieder in der normalen – d. h. ersten – Richtung betrieben. Im HWL-Kanal von der Pumpe zur Düse sind Gasfangtaschen vorgesehen. Demzufolge fängt sich das von der Pumpe unter Betriebsdruck von beispielsweise 14 bar komprimierte Gas in den Gasfangtaschen und nimmt ein minimiertes Volumen ein. Fällt nun die Stromzufuhr aus, fällt auch die Pumpe aus und der Betriebsdruck baut sich ab. Dabei dehnt sich das in den Gasfangtaschen komprimierte Gas aus und treibt die HWL wieder aus den einfriergefährdeten Bauteilen und zumindest teilweise aus dem HWL-Kanal heraus. Die heraustretende HWL kann beispielsweise über Leckagen an der Pumpe und/oder an der Düse abgebaut werden. Ist ein Einspritzventil an der Düse vorgesehen, kann dieses zum Druckabbau Leckagen aufweisen oder es ist sogar „normal offen” ausgeführt.The exhaust aftertreatment device according to the invention circumvents the problem by already

• - when switching on the electrical system via the ignition key or
• - When switching on the electrical system via a "keyless access card" or
• - at engine start

- ie the operating start phase - is sucked by the "backward" running pump gas in the HWL channel. This is for a limited time, such as 10 seconds. Afterwards, the pump is operated again in the normal - ie first - direction. In the HWL channel from the pump to the nozzle gas catch pockets are provided. As a result, the gas compressed by the pump under operating pressure of, for example, 14 bar catches in the gas collecting pockets and occupies a minimized volume. If the power supply fails, the pump will fail and the operating pressure will decrease. In this case, the compressed gas in the gas collecting pockets expands and drives the HWL again from the components at risk of freezing and at least partially out of the HWL channel. The emerging HWL can be broken down, for example, via leaks at the pump and / or at the nozzle. If an injection valve is provided at the nozzle, it may have leaks for pressure reduction or it may even be "normally open".

The freeze-endangered components may be, for example, the said injection valve, the nozzle, various filters, various sensors, in particular pressure / temperature sensors, a pressure accumulator, rigid line sections of the HWL channel or hose couplings of the HWL channel. The freeze-endangered component can also be a supply unit to which the pump is associated.

In one embodiment, a plurality of gas collecting pockets are provided, so that each vulnerable component is protected for itself and / or the gas volume for driving out the HWL is particularly large.

In a further embodiment, the gas is sucked in "backwards" - ie in the second direction - running pump through an open valve through a separate intake passage. This intake channel leads to purified by dirt particles gas. This prevents that Dirt particles can penetrate into the HWL channel and can clog the nozzle or one of the filters. Also, sensitive sensors or the injector are protected from debris. The purified gas can come, for example, from the tank for the HWL. The intake duct may also lead to a filter. As a result, the gas may be air or a gas mixture that forms in the tank.

The valve to the separate intake passage may in particular be a check valve. This is then arranged so that it blocks in the first direction pump and pumping in the second direction promotional pump opens. Such a check valve is particularly inexpensive and easy, since no electrical components are necessary. An example of a check valve is the ball check valve. However, it is also possible to perform the valve as an electromagnetic valve both normally open and normally closed.

From the HWL channel can go off a pressure accumulator, which has a gas collecting pocket. This accumulator can also be arranged "in-line". The pressure accumulator compensates for pressure fluctuations, allows intermittent operation of the pump and forms a very large gas collecting pocket.

The gas collecting bags are in particular designed so that they lie in the installed position above the HWL channel, so that the gas collects there and the HWL flows past it.

The pump can be designed such that the gas is conveyed. This makes it possible to promote the gas to the operating start phase into the tank, so that after subsequent reversal of direction large quantities of gas are conveyed into the HWL channel.

In an advantageous embodiment of the invention, a gear pump is used to promote the HWL as a pump. This gear pump can be designed in a particularly advantageous embodiment as external gear pump. The profile of the gears can be designed in particular with an involute. Here, the HWL is promoted in spaces between the teeth and a housing from an input to an output. Due to its simple construction, this pump is inexpensive, durable and insensitive to freezing HWL.

The pump can be arranged in a particularly advantageous manner in a supply unit. This supply unit then also contains a device for introducing the gas for frost protection of the components. These components are, for example, the central unit and the dosing unit. Also, the supply unit may be connected to the diesel engine coolant circuit, so that the supply unit takes over the defrost function for the tank and the pump. Thus, the coolant and the coolant pump of the diesel engine are used. For the control / regulation of the coolant, a solenoid valve is provided in / on the supply unit.

To drive the one gear, a brushless DC motor can be applied. In this no subject to wear brushes or graphite rods for current application. Instead, an electronic circuit is used. Such a brushless DC motor has an external rotor and is easy to control.

According to a further advantage of the invention, the metering unit for atomizing the HWL in the exhaust stream to a nozzle which is designed as a spray nozzle. The atomization has the advantage of a significantly better distribution with a correspondingly large reactive surface of the HWL compared to the spraying of a barely distributed HWL beam on a hot surface of the exhaust pipe. Thus, a very high proportion of the HWL is fully implemented, so that with low HWL consumption particularly good emissions are achieved. Also, no hot surface is necessary, which would have to be additionally heated during the starting process or in the warm-up phase.

• – einerseits so groß und schwer sind, dass sie nicht mit dem Abgasstrom mitgerissen werden bevor sie vor dem Katalysator chemisch umgesetzt werden und
• – andererseits so klein sind, dass sie gänzlich chemisch umgesetzt werden können.

As a spray nozzle can be carried out in a particularly advantageous manner, a so-called swirl nozzle, which is also referred to as a "pressure swirl atomizer". Such a swirl nozzle is for example from the EP 1 698 768 A1 or the WO 96/11335 is known. In a swirl nozzle several discs with passages are superimposed. These passages direct a spin into the HWL stream before it emerges from an opening which preferably opens in a cone shape. With such a "pressure swirl atomizer", a very specific distribution of different droplet sizes can be achieved at a relatively low pressure. With such a dimensioned distribution of droplet sizes is achieved that the droplets

• - On the one hand are so big and heavy that they are not entrained with the exhaust stream before they are chemically reacted before the catalyst and
• - on the other hand, are so small that they can be completely chemically implemented.

According to a further advantage of the invention, a fine pressure filter is provided as the main filter after the pump, which protects the atomizer nozzle of the dosing unit from clogging. As a result, this fine pressure filter is downstream in the HWL flow arranged the pump. This makes the pressure loss on the fine pressure filter less noticeable than if this pressure filter were arranged in the suction channel in front of the pump. The pump itself can be protected in an advantageous embodiment by means of a coarse suction filter from coarse contamination, with only a slight pressure loss occurs at this coarse suction filter. This also protects the pump from dirt particles. Thus, the reliability of the pump can be guaranteed to a particularly high degree.

The exhaust gas aftertreatment device can be designed in a particularly advantageous embodiment, even without energy supply freezing after the shutdown. As a result, no pumping or valve opening is necessary.

In a particularly advantageous embodiment of the invention, the temperature of the HWL is measured directly in local proximity before the injection into the exhaust gas flow. For this purpose, a temperature sensor is provided in the dosing unit.

Further advantages of the invention will become apparent from the other claims, the description and the drawings.

The invention is explained below with reference to an embodiment.

In the drawing show:

1 schematically the hydraulic circuit of an exhaust aftertreatment device,

2 the components of the exhaust aftertreatment device 1 , where a combination hose is provided,

3 a section of the combination hose 2 in a section along its longitudinal axis, wherein spacers are provided,

4 the combination hose off 3 in a cross-section in front of the spacer,

5 the spacer off 4 in a perspective view,

6 the spacer off 4 and 5 as an item in another view,

7 simplifies the wiring of a control unit of the exhaust aftertreatment device, wherein a pump is also controlled,

8th as a single part in a perspective longitudinal section of a supply unit to which the pump 7 belongs and

9 the central unit off 7 in a cut perspective view.

1 shows the hydraulic circuit of an exhaust aftertreatment device. This has a tank 1 on, which is filled with HWL. Out of this tank 1 sucks a pump 2 the HWL via a pre-filter 3 which is executed as a coarse filter. The pump 2 is powered by a brushless DC motor 4 driven. The pump 2 is a supply unit 55 which also includes a motor control of the DC motor 4 includes. The pump 2 is on the tank 1 assembled. The supply unit 55 has a first gas catching pocket 79 on that too in 8th is shown in more detail.

The pressurized HWL in a first direction 20 is over a line section 6 to a main filter 5 promoted. From the line section 6 goes an accumulator 7 from. With this accumulator 7 is it possible to use the pump 2 to operate intermittently. Moreover, can be with the pressure accumulator 7 Balance pressure fluctuations. In the accumulator 7 Moreover, a second gas collecting bag is formed 56 , The accumulator 7 can be designed in particular as a bubble store.

The pipe section 6 is a HWL channel 57 belonging to the pump 2 to a nozzle 70 leads, which is designed as a spray nozzle in the form of a swirl nozzle.

The HWL channel 57 thus leads from the line section 6 to the said main filter 5 over a flexible hose 10 which is adapted to the specific requirements of the vehicle manufacturer. This is at the two ends of the hose 10 one hose coupling each 11 . 12 intended. The main filter 5 is designed as a pressure filter or fine filter. This main filter 5 follows a rigid line section 13 from which a pressure sensor 14 going on. The rigid line section 13 follows a flexible HWL hose 15 which is also custom. This HWL hose 15 leads to an electromagnetic injection valve 16 into which a temperature sensor 17 is integrated. This electromagnetic injector 16 the HWL splashes over the nozzle 70 in an exhaust gas stream 18 one through a catalyst 72 is directed. The full-surface arrows show the first direction 20 in which the HWL channel 57 the HWL from the tank 1 to the nozzle 70 leads.

From the line section 6 a valve goes 8th from, which is designed as a check valve. This check valve locks in the direction of one to the tank 1 leading intake duct 9 , For this purpose, the intake duct 9 a hydraulic connection between the valve 8th and the tank 1 ago. Thus, by the pump 2 coming pressure from Check valve blocked. Turns the DC motor 4 however, backwards, so that the pump in the second direction 19 promotes, so sucks the pump 2 briefly in the HWL channel 57 , until due to the pressure gradient to the intake 9 the check valve opens automatically. The open check valve creates a small circuit. Then gas - primarily air - out of the tank 1 in the second direction 19 back to the tank 1 promoted. This little circuit is in the 1 apparent and based on the second direction 19 shown with hatched arrows.

So in the approximately 10-second startup phase not HWL through the intake 9 is encouraged leads this intake 9 not to the bottom of the tank 1 but to the top of the tank in the installation position 1 , Possibly. in the intake channel 9 located HWL can thus in the tank 1 drain. In contrast, HWL can not be sucked.

2 shows the components of the exhaust aftertreatment device 1 , It can be seen that the supply unit 55 with the pump 2 both outside the tank 1 , as well as inside the tank 1 can be arranged. The pump 2 is designed here as a gear pump. This gear pump is the in 8th illustrated supply unit 55 belong. The accumulator 7 is not shown here, since it is only an add-on additional usable module of the exhaust aftertreatment device, which is not necessary in every vehicle configuration. The supply unit 55 follows the central unit 21 in which the pressure sensor 14 and the main filter, not shown in the drawing for a better overview 5 are housed. Moreover, it is a fan 22 in the central unit 21 integrated, which hot air into a combination hose 30 can inject it, so that inside the HWL tube 15 located HWL can be preheated or thawed. Moreover, it is possible with this blower 22 even cool air in the hose 15 to blow to the injector 16 to cool that of a dosing unit 23 is associated. This is the dosing unit 23 with the injector 16 and the temperature sensor 17 at the other end of the combination hose 15 appropriate. Because the dosing unit 23 also an electromagnet 24 also carries an electrical line 25 to the end 26 of the combination hose 15 which is connected to the central unit 21 connected. At this end 26 occurs the electrical line 25 off and leads to a connector 27 to the central unit 21 , Moreover, this is the end 26 on the combination hose 15 also a connector 28 for the fan 22 intended. Radial inside a jacket 31 for the fan air duct is the HWL hose 15 intended. This HWL hose 15 is at the end 26 on a connector 29 plugged. This connector 29 leads over the partially within a housing part 33 extending HWL channel 57 to the main filter, not shown 5 , This main filter 5 is also inside the case 33 arranged. The HWL channel 57 is inside the housing part 33 drilled, which with the not apparent here main filter 5 is coupled. The pressure sensor 14 is on the housing part 33 screwed. From the housing part 33 works similar to the connector for the HWL hose 15 another connector 35 on which the flexible hose 10 plugged in, then in already too 1 explained manner to the pump 2 leads.

Because the housing part 33 is rigid and the HWL channel 57 leads, goes from the holes for the HWL channel 57 a third gas collecting pocket in the housing part 33 from. This third gas collecting pocket is in the housing part 33 arranged and thus not visible in the drawing. The third gas collecting pocket takes on the normal operation of the pump 2 compressed gas on. This gas in the third gas pocket expands again with the pump off 2 or in the second direction 19 pump 2 , Then the holes in the housing part 33 freed from parts of the HWL, so that a freezing possibly still in the holes located HWL not destroying the housing 33 can lead.

• – Luftstrom aus dem Gebläse 22 als auch
• – die HWL als auch
• – die elektrischen Leitungen 25 für den Elektromagneten 24 als auch
• – in 4 und 7 ersichtliche Signalleitungen 36 des Temperatursensors 17.

The in a perspective section over a section in 3 illustrated combination hose 30 thus leads both the

• - Air flow from the blower 22 as well as
• - the HWL as well
• - the electric wires 25 for the electromagnet 24 as well as
• - in 4 and 7 apparent signal lines 36 of the temperature sensor 17 ,

The HWL is connected via the centrally arranged HWL hose 15 guided. About spacers 37 is radially outside of this HWL hose 15 the jacket 31 kept positioned. The spacers 37 also carry both the electrical wires 25 as well as the signal lines 36 near the HWL tube 15 ,

The jacket cover 31 is executed with compressed wrinkles. This is the combination hose 30 Relatively flexibly deployable. Thus, a hose type for different vehicle types is applicable.

The spacer 37 has the shape of a spoked wheel. This shows the rim 38 the spoked wheel material weakening 39 on, diametrically opposite a clip connection 40 lies. This makes it possible the rim 38 to open the HWL hose 15 , the electrical signal lines 36 , and the electrical wires 25 appeal. Here are the electrical signal lines 36 , the electrical wires 25 and the HWL hose 15 in a hub 41 of the spacer 37 used. This hub 41 is in the diametral between the clip connections 40 and the material weakening 39 separated. Each of the two thus resulting hub halves 42 . 43 is each with two memories 44 . 45 respectively. 46 . 47 with the rim 38 connected. Thus, each hub half 42 respectively. 43 one of these associated rim half 48 . 49 on. The hub 41 has on the inside recess for receiving the electrical signal line 36 or the electrical line 25 on. Between the stores 44 to 47 form four cake piece-shaped passages for the air flow of the blower 22 ,

In 7 is still apparent that the central unit 21 a control unit 50 having. The control unit 50 includes the central processing unit or ECU 53 and the 24V power supply 51 for the supply unit 55 and the vehicle ignition 58 , Moreover, the 24 V power supply offers 51 a 5V line 54 leading to the pressure sensor 14 leads. This pressure sensor 14 gives signals to the central processing unit ECU 53 out. Furthermore, the 5 V line leads 54 to the central processing unit ECU 53 ,

The central processing unit ECU 53 receives a signal from a tank level sensor of the tank 1 , Moreover, the central processing unit ECU 53 Signals from the DC motor 4 the pump 2 , Furthermore, the central processing unit ECU 53 a signal from the memory module 52 the dosing unit 23 , The central processing unit ECU 53 controls the electromagnet directly 24 in the dosing unit 23 at. The central processing unit ECU 53 communicates with the engine control 59 ,

It is also the dosing unit 23 with the injector 16 seen. Here is an annular channel 73 intended. This ring channel 73 runs from a diameter-expanded area 74 near the electromagnet 24 up to a valve seat 77 near the nozzle 70 , The nozzle 70 is in installation position below the electromagnet 24 arranged. Thus, a fourth gas collecting bag is formed 75 in the diameter-expanded area 74 forms. This fourth gas catcher bag 75 protects in particular the dosing unit 23 before freezing HWL.

• – der Pumpe 2,
• – der ersten Gasfangtasche 79,
• – einem Zulaufkanal 62 für die HWL,
• – einem Ablaufkanal 63 für die HWL,
• – einem Anschluss für den Ansaugkanal 9 mit dem Rückschlagventil 8,
• – einem Kühlmitteleingang 80,
• – einem Kühlmittelausgang 81,
• – einem Elektromagnetventil 82 zur Steuerung/Regelung des Kühlmittels und
• – dem zeichnerisch nicht ersichtlichen Gleichstrommotor 4.

8th shows supply unit 55 With

• - the pump 2 .
• - the first gas catch bag 79 .
• - An inlet channel 62 for the HWL,
• - a drainage channel 63 for the HWL,
• - a connection for the intake duct 9 with the check valve 8th .
• - a coolant inlet 80 .
• - a coolant outlet 81 .
• - a solenoid valve 82 for controlling / regulating the coolant and
• - The graphically not visible DC motor 4 ,

The DC motor 4 is about a graphically not shown shaft with a gear 60 connected is. This gear 60 meshes with another gear 61 , which moved parallel to the first-mentioned gear 60 is arranged. The two gears 60 . 61 rotate in a pump housing 64 , which has a feed channel 62 and a drain channel 63 having. Here, the HWL in the interdental spaces of the two gears 60 . 61 along inner walls of the pump housing 64 guided, in which the gears 60 . 61 are used. The pump builds a pressure of about 14 bar up.

The first gas catching bag 79 is in installation position above a channel 68 arranged by the pump 2 to the drainage channel 63 leads. Here is this channel 68 open to the gas catcher 79 , The gas catcher bag 79 adjacent pump 2 is frost protected. The gas catching bag 79 is in a supply unit housing 71 arranged and with a lid 32 closed, with a sealing ring 69 is sealed.

The solenoid valve 82 for controlling the coolant for cooling the diesel engine is to the power unit housing 71 screwed. The solenoid valve 82 controls the flow of cooling water through the supply unit housing 71 , so that the HWL in the supply unit housing 71 can be thawed. It is also possible with the cooling water in the tank 1 thaw existing and possibly frozen HWL. The solenoid valve 82 controls the flow of cooling water according to requirements.

9 shows the central unit 21 in a perspective view. The fan 22 and the control unit 50 extend perpendicular to each other. For heat dissipation, the control unit 50 a screwed lid 65 with cooling fins 67 on.

The main filter 5 has a fifth gas catching pocket 76 on. A sixth gas catching bag 78 is in the pressure sensor 14 intended.

The described embodiments are only exemplary embodiments. A combination of the described features for different embodiments is also possible. Further, in particular not described features of the device parts belonging to the invention are to be taken from the geometries of the device parts shown in the drawings.

LIST OF REFERENCE NUMBERS

1

tank

2

pump

3

prefilter

4

DC motor

5

main filter

6

line section

7

accumulator

8th

check valve

9

intake port

10

flexible hose

11

hose coupling

12

hose coupling

13

line section

14

pressure sensor

15

HWL hose

16

Injector

17

temperature sensor

18

exhaust gas line

19

second direction

20

first direction

21

central processing unit

22

fan

23

dosing

24

electromagnet

25

electrical line

26

End of the combination hose

27

Connection plug temperature sensor 17

28

Connecting plug blower 22

29

Connector for HWL hose 15

30

Combihose

31

liner shell

32

cover

33

housing part

34

connection coupling

35

Further connection plug

36

Electrical signal line

37

spacer

38

rim

39

material weakening

40

clip connection

41

hub

42

hub half

43

hub half

44

spoke

45

spoke

46

spoke

47

spoke

48

rim half

49

rim half

50

control unit

51

24V power supply

52

memory chip

53

ECU

54

5V line

55

supply unit

56

second gas catching bag

57

HWL Channel

58

vehicle ignition

59

motor control

60

gear

61

gear

62

inlet channel

63

drain channel

64

pump housing

65

cover

66

Lüftungsausnehmungen

67

cooling fins

68

channel

69

seal

70

jet

71

Supply unit housing

72

catalyst

73

annular channel

74

diameter-extended range

75

fourth gas catching bag

76

fifth gas catching bag

77

valve seat

78

sixth gas catching bag

79

first gas catch bag

80

Coolant inlet

81

Coolant outlet

82

Solenoid valve

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

• WO 2009/010569 A1 [0003, 0003]
• DE 102009037564 A1 [0003]
• US 2009/0205316 [0004]
• DE 102011053742 [0005]
• EP 1698768 A1 [0022]
• WO 96/11335 [0022]

Claims (15)

Exhaust after-treatment device with a control unit ( 53 ) for controlling a pump ( 2 ) in two opposite directions, the pump ( 2 ) in the first direction ( 20 ) a HWL from a tank ( 1 ) through a HWL channel ( 57 ) to a nozzle ( 70 ), which converts the HWL into an exhaust gas stream ( 18 ), whereby in the HWL channel ( 57 ) between the nozzle ( 70 ) and the pump ( 2 ) at least one gas collecting bag ( 56 . 71 . 75 . 76 . 78 ) is provided, in which a gas from the in the first direction ( 20 ) pump ( 2 ) is pressurized, wherein the gas in an operating start phase of the in the second direction ( 19 ) pump ( 2 ) in the HWL channel ( 57 ) is sucked. Exhaust after-treatment device according to claim 1, characterized in that a plurality of gas collecting pockets ( 56 . 71 . 75 . 76 . 78 ) are provided. Exhaust after-treatment device according to one of the preceding claims, characterized in that the gas in the second direction ( 19 ) pump ( 2 ) via an open valve ( 8th ) through a separate intake channel ( 9 ), which travels to cleaned of dirt particles gas. Exhaust after-treatment device according to claim 3, characterized in that the separate intake duct ( 9 ) to the tank ( 1 ) in installation position above a surface of HWL drives. Exhaust after-treatment device according to claim 3 or 4, characterized in that the valve ( 8th ) is a check valve which is arranged so that in the first direction ( 20 ) pump and locks in the second direction ( 19 ) pump ( 2 ) opens. Exhaust after-treatment device according to one of the preceding claims, characterized in that the pump ( 2 ) is a gear pump. Exhaust after-treatment device according to one of the preceding claims, characterized in that of the HWL channel ( 57 ) an accumulator 7 which has a gas collecting bag ( 56 ) having. Exhaust after-treatment device according to one of the preceding claims, characterized in that in the HWL channel ( 57 ) a filter ( 5 ) is provided, a gas collecting bag ( 76 ) having. Exhaust after-treatment device according to one of the preceding claims, characterized in that the nozzle ( 70 ) of a dosing unit ( 23 ), which is one with an electromagnet ( 24 ) actuated injection valve ( 16 ), wherein an annular channel ( 73 ) of a diameter-extended region ( 74 ) near the electromagnet ( 24 ) to a valve seat ( 77 ) near the nozzle ( 70 ), which in the installed position below the electromagnet ( 24 ) is arranged so that a gas collecting bag ( 75 ) in the diameter-extended region ( 74 ). Exhaust after-treatment device according to one of the preceding claims, characterized in that the nozzle ( 70 ) of a dosing unit ( 23 ), which is one with an electromagnet ( 24 ) actuated injection valve ( 16 ), which is closed in the operation start phase. Exhaust after-treatment device according to one of the preceding claims, characterized in that the gas-collecting pocket ( 78 ) in a sensor ( 14 ) is provided. Exhaust after-treatment device according to one of the preceding claims, characterized in that the pump ( 2 ) of a supply unit ( 55 ) with a supply unit housing ( 71 ) that a gas collecting bag ( 79 ) having. Exhaust after-treatment device according to claim 12, characterized in that the supply unit housing ( 71 ) an inlet channel ( 62 ) and a drain channel ( 63 ) for coolant of a diesel engine. A method for exhaust aftertreatment, characterized in that - in a first step on a signal to start operation, a pump ( 2 ) a gas via a valve ( 8th ) in a second direction ( 19 ), which of a first direction ( 20 ), - in a second process step, the pump ( 2 ) a HWL and the gas in the first direction ( 20 ) along a HWL channel ( 57 ) with at least one gas collecting bag ( 56 respectively. 71 respectively. 75 respectively. 76 respectively. 78 ), so that the gas in the gas pocket ( 56 respectively. 71 respectively. 75 respectively. 76 respectively. 78 ) begins, - in a subsequent phase of operation, the HWL on the gas collecting bag ( 56 respectively. 71 respectively. 75 respectively. 76 respectively. 78 ) conveyed over and over a nozzle ( 70 ) in an exhaust gas stream ( 18 ) is injected. A method according to claim 14, characterized in that the gas is shut down Pump ( 2 ) expands and HWL at least partially from the HWL channel ( 57 ) promotes out.

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