Exhaust aftertreatment system

Abstract

Exhaust aftertreatment device, in which a HWL is conveyed through a flexible HWL hose (15) to a metering unit (23) with a nozzle (70) which injects the HWL into an exhaust gas stream (18), wherein the HWL hose (15) is arranged within a jacket (31), wherein a spacer (37) maintains a distance between the HWL hose (15) and the jacket (31), wherein a blower (22) is provided with which air can be conveyed within the jacket (31) to the metering unit (23).

Description

[0001] The invention relates to an exhaust gas aftertreatment device according to the one-part patent claim 1.

[0002] In the following, urea-water solution is referred to as HWL.

[0003] EP 1 818 588 A1 already discloses a hose assembly for an exhaust aftertreatment system, within which a temperature control medium is guided. A cavity is provided between a hose of the hose assembly and the temperature control medium.

[0004] From EP 2 102 464 B1 an exhaust gas aftertreatment device is known which has a heat conducting sleeve.

[0005] From US 2011 / 0036079 A1 an exhaust gas aftertreatment device is known in which HWL is guided through a line, outside of which air is guided by a compressor.

[0006] WO 2006 / 136306 A1 discloses a supply line for an exhaust aftertreatment system in which a hose containing reducing agent runs inside a metal pipe. Chambers formed between the inner wall of the metal pipe and the outer wall of the hose can be filled with compressed air to compress the hose.

[0007] From DE 199 20 059 A1 a multi-chamber hose is known which has an inner conveying chamber which conducts a conveying fluid and is surrounded by longitudinal chambers filled with a temperature compensation fluid.

[0008] The object of the invention is to provide an exhaust gas aftertreatment device that can be adapted to thermal ambient conditions.

[0009] This object is achieved according to the invention with the features of patent claim 1.

[0010] The invention can be used in both passenger cars and commercial vehicles, since the exhaust aftertreatment system according to the invention does not require compressed air. Such other exhaust aftertreatment systems using compressed air are referred to as "air-assisted systems."

[0011] In the exhaust aftertreatment system according to the invention, a UWP is conveyed through a flexible UWP hose to a dosing unit with a nozzle. The nozzle injects the UWP into an exhaust stream. The UWP hose is arranged within a jacket. A spacer maintains a gap between the UWP hose and the jacket. A fan is provided, with which air can be conveyed within the jacket to the dosing unit. This allows the UWP hose and the dosing unit to be cooled and heated. Temperature management is possible there.

[0012] This fan can in particular be driven by an electric motor.

[0013] The dosing unit for atomizing the urea solution in the exhaust stream features a nozzle, which can be designed as an atomizing nozzle. Compared to spraying a barely distributed urea solution jet onto a hot surface of the exhaust pipe, atomization offers the advantage of significantly better distribution, resulting in a correspondingly large reactive surface for the urea solution. This allows a very high proportion of the urea solution to be fully converted, resulting in particularly good exhaust emissions with low urea consumption. Furthermore, no hot surface is required, which would have to be additionally heated during the start-up process or warm-up phase.

[0014] A so-called swirl nozzle, also known as a “pressure swirl atomizer,” can be used particularly advantageously as an atomizer nozzle. Such a swirl nozzle is known, for example, from EP 1 698 768 A1 or WO 96 / 11 335 A1. In a swirl nozzle, several discs with openings are placed one above the other. These openings introduce a swirl into the urea solution stream before it exits from an opening that preferably opens conically. 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, it is achieved that the droplets - on the one hand, they are so large and heavy that they are not carried along with the exhaust gas flow before they are chemically converted in front of the catalyst and - on the other hand, are so small that they can be completely chemically converted.

[0015] This dosing unit with the nozzle and / or the UWL hose can thus be heated or cooled in a particularly advantageous manner according to the invention. For this purpose, an air flow is conveyed along the dosing unit with the nozzle and / or the UWL hose by a blower. The blower can be designed to blow and / or suck. A heater can be provided on the blower, which enables the blower to blow hot air. With such hot air, for example, frozen UWL in the dosing unit and / or the UWL hose can be thawed so that UWL can be injected into the exhaust system as soon as the engine is started. In order to thaw the UWL hose particularly evenly with warm air during frost operation, the UWL hose can be guided centrally in the casing.

[0016] The fan can also be operated without heating and cooled with air, which is particularly beneficial for the service life of the electrical coil of the electromagnet for the electromagnetic valve.

[0017] This electromagnetic valve in the dosing unit can be particularly advantageously designed as a needle valve. A sensor can be particularly advantageously provided in the area of ​​the dosing unit. The sensor can be designed, in particular, as a temperature sensor and / or a pressure sensor. Thus, in this particularly advantageous embodiment of the invention, the temperature of the UWL is measured directly in the local vicinity before it is injected into the exhaust stream.

[0018] The dosing unit and a pump of a supply unit can thus be particularly advantageously spaced apart from each other over a large distance - for example 0.5 m.

[0019] The blower can be connected to the dosing unit via the jacket. The jacket then serves to distribute the air evenly along the UWW hose. If necessary, an electrical cable for the electromagnet, also housed within the jacket, can be protected from environmental influences.

[0020] The exhaust aftertreatment system according to the invention is particularly easy to install. For example, when assembling the urea-based hose and line, the dosing unit can be pre-assembled to the urea-based hose using clip connections. This assembly, consisting of the urea-based hose and dosing unit, can then be delivered pre-assembled to the vehicle manufacturer. The electrical lines can also be clipped together for easy installation.

[0021] The spacers according to the invention guide the UHT hose in an advantageous manner and can even be designed as a centering device for the UHT hose. Furthermore, identical spacers can be used for UHT hoses of different lengths in different vehicle applications. Hose centering is guaranteed even in extreme installation positions. Installation is simple. The spacers can be manufactured from plastic, inexpensively and lightweight.

[0022] In a particularly advantageous embodiment of the invention, the spacer is split. In an advantageous further development, the spacer can be closable, so that the UWW hose inserted in the open state is held at a distance from the casing when the spacer is closed. A clip connection can be provided to securely close the spacer.

[0023] Further advantages of the invention emerge from the further patent claims, the description and the drawings.

[0024] The invention is explained below using an embodiment.

[0025] The drawing shows: Fig. 1 schematically shows the hydraulic circuit of an exhaust aftertreatment device, Fig. 2 the components of the exhaust aftertreatment system Fig. 1, whereby a combination hose is provided, Fig. 3 a section of the combination hose from Fig. 2 in a section along its longitudinal axis, with spacers provided, Fig. 4 the combination hose Fig. 3 in a cross-section in front of the spacer, Fig. 5 the spacer from Fig. 4 in a perspective view, Fig. 6 the spacer from Fig. 4 and Fig. 5 as a single part in a different view, Fig. 7 simplifies the wiring of a control unit of the exhaust aftertreatment system, which also controls a pump, Fig. 8 as a single part in a perspective longitudinal section a supply unit to which the pump from Fig. 7 and Fig. 9 the central unit Fig. 7 in a cut perspective view.

[0026] Fig. Figure 1 shows the hydraulic circuit of an exhaust aftertreatment system. This system comprises a tank 1 filled with urea. From this tank 1, a pump 2 draws the urea through a pre-filter 3, which is designed as a coarse filter. The pump 2 is driven by a brushless DC motor 4. The pump 2 is associated with a supply unit 55, which also includes a motor control unit for the DC motor 4. The pump 2 is mounted on the tank 1. The supply unit 55 has a first gas collection pocket 79, which is also Fig. 8 is shown in more detail.

[0027] The pressurized UWL is conveyed in a first direction 20 via a line section 6 to a main filter 5. A pressure accumulator 7 branches off from the line section 6. This pressure accumulator 7 makes it possible to operate the pump 2 intermittently. Furthermore, pressure fluctuations can be compensated for with the pressure accumulator 7. Furthermore, a second gas trap pocket 56 is formed in the pressure accumulator 7. The pressure accumulator 7 can be designed, in particular, as a bladder accumulator.

[0028] The line section 6 belongs to a HWL channel 57, which leads from the pump 2 to a nozzle 70, which is designed as an atomizing nozzle in the form of a swirl nozzle.

[0029] The UWL channel 57 thus leads from the line section 6 to the aforementioned main filter 5 via a flexible hose 10, which is adapted to the specific requirements of the vehicle manufacturer. For this purpose, a hose coupling 11, 12 is provided at each end of the hose 10. The main filter 5 is designed as a pressure filter or fine filter. This main filter 5 is followed by a rigid line section 13, from which a pressure sensor 14 branches off. The rigid line section 13 is followed by a flexible UWL hose 15, which is also customer-specific. This UWL hose 15 leads to an electromagnetic injection valve 16, into which a temperature sensor 17 is integrated. This electromagnetic injection valve 16 injects the UWL via the nozzle 70 into an exhaust gas stream 18, which is passed through a catalytic converter 72. The solid arrows show the first direction 20 in which the UWL channel 57 guides the UWL from the tank 1 to the nozzle 70.The electromagnetic injection valve 16 is designed as a needle valve.

[0030] A valve 8, designed as a check valve, branches off from line section 6. This check valve blocks the flow towards an intake channel 9 leading to tank 1. For this purpose, intake channel 9 establishes a hydraulic connection between valve 8 and tank 1. Thus, pressure coming from pump 2 is blocked by the check valve. If, however, the DC motor 4 rotates backwards, so that the pump delivers in the second direction 19, pump 2 briefly draws air into the HWL channel 57 until the check valve opens automatically due to the pressure drop to the intake channel 9. A small circuit is formed by the open check valve. Gas - primarily air - is then pumped from tank 1 in the second direction 19 back into tank 1. This small circuit is in the Fig. 1 and is shown by the second direction 19, which is indicated by hatched arrows.

[0031] To prevent urea from being pumped through the intake duct 9 during the approximately 10-second start-up phase, this intake duct 9 does not lead to the bottom of the tank 1, but rather to the area of ​​the tank 1 that is at the top in the installed position. Any urea contained in the intake duct 9 can thus drip into the tank 1. However, urea cannot be sucked in.

[0032] Fig. 2 shows the components of the exhaust aftertreatment system from Fig. 1. It is evident that the supply unit 55 with the pump 2 can be arranged both outside the tank 1 and inside the tank 1. The pump 2 is designed here as a gear pump. This gear pump is the Fig. 8. The pressure accumulator 7 is not shown here, as it is only an add-on module of the exhaust gas aftertreatment system that can be used additionally and is not necessary in every vehicle configuration. The supply unit 55 is followed by the central unit 21, in which the pressure sensor 14 and the main filter 5 (not shown in the drawing for clarity) are housed. Furthermore, an electric motor-driven blower 22 is integrated into the central unit 21, which can blow hot air into a combination hose 30 so that the UWL located inside the UWL hose 15 can be preheated or thawed. Furthermore, it is possible to use this blower 22 to blow cool air into the hose 15 in order to cool the injection valve 16, which is associated with a metering unit 23.For this purpose, the dosing unit 23 with the injection valve 16 and the temperature sensor 17 is attached to the other end of the combination hose 15. Since the dosing unit 23 also has an electromagnet 24, an electrical line 25 also leads to the end 26 of the combination hose 15, which is connected to the central unit 21. At this end 26, the electrical line 25 exits and leads to a connector plug 27 on the central unit 21. Furthermore, a connector plug 28 for the blower 22 is provided at this end 26 on the combination hose 15. The HWL hose 15 is provided radially within a jacket sleeve 31 for the blower air duct. This HWL hose 15 is plugged onto a connector plug 29 at end 26. This connector plug 29 leads via the HWL channel 57, which runs partially within a housing part 33, to the main filter 5, not shown in detail. This main filter 5 is also arranged within the housing part 33.The UWL channel 57 is drilled into the housing part 33, which is coupled to the main filter 5 (not visible here). The pressure sensor 14 is screwed to the housing part 33. Similar to the connector for the UWL hose 15, another connector 35 extends from the housing part 33, onto which the flexible hose 10 is plugged. Fig. 1 leads to pump 2.

[0033] Since the housing part 33 is rigid and carries the UHMW channel 57, a third gas collection pocket in the housing part 33 branches off from the holes for the UHMW channel 57. This third gas collection pocket is arranged in the housing part 33 and is therefore not visible in the drawing. The third gas collection pocket absorbs compressed gas during normal operation of the pump 2. This gas in the third gas collection pocket expands again when the pump 2 is switched off or when the pump 2 is conveying in the second direction 19. The holes in the housing part 33 are then cleared of parts of the UHMW, so that any freezing of any UHMW still present in the holes cannot lead to the destruction of the housing 33.

[0034] The perspective section over a section in Fig. The combination hose 30 shown in Figure 3 thus carries out both the - Air flow from the fan 22 as well as - the HWL as well as - the electrical lines 25 for the electromagnet 24 as well as - in Fig. 4 and Fig. 7 visible signal lines 36 of the temperature sensor 17.

[0035] The urea is routed through the centrally located urea hose 15. The jacket 31 is held in place radially outside this urea hose 15 by spacers 37. The spacers 37 also guide both the electrical lines 25 and the signal lines 36 near the urea hose 15.

[0036] The outer casing 31 is designed with compressed folds as a corrugated hose 85. This allows the combination hose 30 to be installed relatively flexibly. This allows one hose type to be used for different vehicle types.

[0037] The spacer 37 is shaped like a spoked wheel. The rim 38 of the spoked wheel has a weakened portion 39 located diametrically opposite a clip connection 40. This allows the rim 38 to be opened to insert the urea-based water hose 15, the electrical signal lines 36, and the electrical lines 25. The electrical signal lines 36 and the electrical lines 25 are inserted into receptacles 83, 84 in a hub 41 of the spacer 37. These receptacles 83, 84 are designed as indentations on the inside of the hub 41. The urea-based water hose 15 is inserted centrally into the hub 41. This hub 41 is separated diametrically between the clip connection 40 and the weakened portion 39. Each of the two resulting hub halves 42, 43 is connected to the rim 38 by two reservoirs 44, 45 and 46, 47, respectively. Thus, each hub half 42 or 43 has a rim half 48, 49 associated with it.The hub 41 has a recess on its inside for accommodating the electrical signal line 36 or the electrical line 25. Between the reservoirs 44 to 47, four pie-shaped passages are formed for the air flow of the fan 22.

[0038] In Fig. 7 also shows that the central processing unit 21 has a control unit 50. The control unit 50 includes the central processing unit (ECU) 53 and the 24V power supply 51 for the supply unit 55 and the vehicle ignition 58. Furthermore, the 24V power supply 51 provides a 5V line 54 that leads to the pressure sensor 14. This pressure sensor 14 outputs signals to the central processing unit (ECU) 53. Furthermore, the 5V line 54 leads to the central processing unit (ECU) 53.

[0039] The central processing unit (ECU) 53 receives a signal from a tank level sensor of tank 1. Furthermore, the central processing unit (ECU) 53 receives signals from the DC motor 4 of the pump 2. Furthermore, the central processing unit (ECU) 53 receives a signal from the memory module 52 of the dosing unit 23. The central processing unit (ECU) 53 directly controls the electromagnet 24 in the dosing unit 23. The central processing unit (ECU) 53 communicates with the engine control unit 59.

[0040] The metering unit 23 with the injection valve 16 is also visible. An annular channel 73 is provided. This annular channel 73 extends from a larger-diameter region 74 near the electromagnet 24 to a valve seat 77 near the nozzle 70. The nozzle 70 is arranged below the electromagnet 24 in the installed position. Thus, a fourth gas trap pocket 75 is formed in the larger-diameter region 74. This fourth gas trap pocket 75 protects, in particular, the metering unit 23 from freezing urea.

[0041] Fig. 8 shows supply unit 55 with - pump 2, - the first gas collection bag 79, - an inlet channel 62 for the HWL, - a drain channel 63 for the HWL, - a connection for the intake duct 9 with the check valve 8, - a coolant inlet 80, - a coolant outlet 81, - a solenoid valve 82 for controlling / regulating the coolant and - the DC motor 4, which is not shown in the drawing.

[0042] The DC motor 4 is connected to a gear 60 via a shaft (not shown in the drawing). This gear 60 meshes with another gear 61, which is arranged parallel to the first-mentioned gear 60. The two gears 60, 61 rotate in a pump housing 64, which has an inlet channel 62 and an outlet channel 63. The urea is guided in the spaces between the teeth of the two gears 60, 61 along the inner walls of the pump housing 64, into which the gears 60, 61 are inserted. The pump builds up a pressure of approximately 14 bar.

[0043] The first gas collection pocket 79 is arranged in the installed position above a channel 68 leading from the pump 2 to the drain channel 63. This channel 68 is open to the gas collection pocket 79. The pump 2 adjacent to the gas collection pocket 79 is frost-protected. The gas collection pocket 79 is arranged in a supply unit housing 71 and closed with a cover 32, which is sealed with a sealing ring 69.

[0044] The solenoid valve 82 for controlling / regulating the coolant for cooling the diesel engine is screwed to the supply unit housing 71. The solenoid valve 82 controls the flow of cooling water through the supply unit housing 71 so that the UWL in the supply unit housing 71 can be thawed. The cooling water can also be used to thaw any frozen UWL present in tank 1. The solenoid valve 82 controls the flow of cooling water as needed.

[0045] Fig.Figure 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 has a screwed cover 65 with cooling fins 67.

[0046] The main filter 5 has a fifth gas trap 76. A sixth gas trap 78 is provided in the pressure sensor 14.

[0047] The described embodiments are merely exemplary configurations. A combination of the described features for different embodiments is also possible. Further features of the device components belonging to the invention, in particular those not described above, can be found in the geometries of the device components shown in the drawings. List of reference symbols 1 tank 2 pumps 3 pre-filters 4 DC motor 5 main filters 6 line sections 7 pressure accumulators 8 Check valve 9 Intake duct 10 flexible hose 11 Hose coupling 12 hose coupling 13 line sections 14 Pressure sensor 15 HWL hose 16 Injector 17 Temperature sensor 18 Exhaust gas flow 19 second direction 20 first direction 21 Central unit 22 blowers 23 Dosing unit 24 Electromagnet 25 electrical cables 26 End of the combination hose 27 Temperature sensor connector 17 28 Fan connector 22 29 Connector plug HWL hose 15 30 combination hose 31 Coat shell 32 lids 33 Housing part 34 connection coupling 35 Additional connector 36 Electrical signal cable 37 spacers 38 rim 39 Material weakening 40 clip connection 41 Hub 42 hub half 43 Hub half 44 spokes 45 spokes 46 spokes 47 spokes 48 rim half 49 rim half 50 control unit 51 24V power supply 52 memory module 53 ECU 54 5V line 55 supply unit 56 second gas catcher bag 57 HWL channel 58 Vehicle ignition 59 Engine control 60 gear 61 gear 62 inlet channel 63 Drain channel 64 pump housing 65 lids 66 ventilation recesses 67 cooling fins 68 channel 69 Sealing ring 70 nozzle 71 Supply unit housing 72 Catalyst 73 Ring Canal 74 diameter-extended area 75 fourth gas trap pocket 76 fifth gas trap pocket 77 Valve seat 78 sixth gas trap pocket 79 first gas trap 80 Coolant inlet 81 Coolant outlet 82 Solenoid valve 83 recording 84 recording 85 corrugated hose

Claims

[1] Exhaust gas aftertreatment device, with which a UWL is conveyed through a flexible UWL hose (15) to a dosing unit (23) with a nozzle (70) which injects the UWL into an exhaust gas flow (18), wherein the UWL hose (15) is arranged within a jacket (31), wherein a spacer (37) maintains a distance between the UWL hose (15) and the jacket (31), wherein a blower (22) is provided, with which air can be conveyed within the jacket (31) to the dosing unit (23). [2] Exhaust gas aftertreatment device according to claim 1, characterized by that a receptacle (83 or 84) for guiding an electrical line (25, 36) is provided within the jacket (31). [3] Exhaust gas aftertreatment device according to claim 2, characterized by that the spacer (37) has the receptacle (83 or 84). [4] Exhaust gas aftertreatment device according to one of the preceding claims, characterized bythat the HWL hose (15) is inserted into a hub (41) of the spacer (37). [5] Exhaust gas aftertreatment device according to one of the preceding claims, characterized by that the spacer (37) has a clip connection (40) for inserting the HWL hose (15). [6] Exhaust gas aftertreatment device according to claim 5, characterized by that the spacer (37) is divided and can be closed with the clip connection (40), so that a HWL hose (15) inserted in the open state of the clip connection (40) is held at a distance from the jacket cover (31) in the closed state of the clip connection (40). [7] Exhaust gas aftertreatment device according to one of the preceding claims, characterized by that a plurality of spacers (37) are provided within the casing (31), which are arranged axially spaced from one another with respect to a longitudinal axis of the casing (31). [8] Exhaust gas aftertreatment device according to one of the preceding claims, characterized by that the jacket cover (31) is designed as a corrugated hose (85). [9] Exhaust gas aftertreatment device according to one of the preceding claims, characterized by that an electrical line (25, 36) is laid within the sheath (31), which leads to a connection plug (27) which is arranged outside the sheath (31). [10] Exhaust gas aftertreatment device according to claim 9, characterized by that the connection plug (27) for the electrical line (25, 36) and a connection plug (28) for the blower (22) and a connection plug (29) for the HWL hose (15) are connected to a housing part (33) of a central unit (21) which has the blower (22).

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