Reducing agent addition and processing system of a motor vehicle

Abstract

Reducing agent addition and treatment system (1) of a motor vehicle, for adding a liquid reducing agent to exhaust gas emitted by an internal combustion engine of the motor vehicle and for treating the added reducing agent in the exhaust gas, comprising - an injector (3) associated with a reducing agent dosing unit (2) which can spray a reducing agent spray jet (6) into the exhaust gas, - a mixing tube (7) arranged in an exhaust tract of the internal combustion engine with a first and a second axial mixing tube end (8, 9), and - a funnel element (10) arranged in or on the mixing tube (7) in the region of the first mixing tube end (8), widening conically in the direction from the first mixing tube end (8) to the second mixing tube end (9) with a predetermined widening angle, wherein - the mixing tube (7) and the funnel element (10) are designed as hollow bodies of revolution with a perforated outer surface, and the perforation (11) of the mixing tube (7) is at least predominantly larger in area than the perforation (12) of the funnel element (10), - the funnel element (10) has a through-opening (13) at its end associated with the first mixing tube end (8), and - the reducing agent metering unit (2) is arranged such that the injector (3) can spray the reducing agent spray jet (6) through the through-opening (13) into the interior of the funnel element (10), characterized in that the injector (3) has an end-end injector tip (4), wherein the injector tip (4) and the through-opening (13) of the funnel element (10) each have a circumferential contour that is at least approximately circular, and an outlet opening (5) for the reducing agent is arranged at least approximately centrally at the injector tip (4), and the outlet opening (5) and a center point of the through-opening (13) are located at least approximately on the axis of rotation (14) of the funnel element (10), and the injector tip (4) is arranged opposite the funnel element (10) at a small distance from the through-opening (13),that an annular gap (15) is formed by the injector tip (4) and a shell surface area of ​​the funnel element (10) surrounding the passage opening (13), through which exhaust gas can flow into the interior of the funnel element (10).

Description

[0001] The invention relates to a reducing agent addition and treatment system of a motor vehicle, for adding a liquid reducing agent to exhaust gas emitted by an internal combustion engine of the motor vehicle and for treating the added reducing agent in the exhaust gas.

[0002] For exhaust gas aftertreatment, liquid reducing agents such as mineral oil fuel or aqueous urea solution are often introduced into the exhaust gas of internal combustion engines. This poses a problem with regard to the treatment of the reducing agent introduced in liquid form with regard to the desired uniform distribution and with regard to evaporation. With aqueous urea solution, there is also the problem of releasing the ammonia required for selective catalytic nitrogen oxide reduction from the urea through hydrolysis and / or thermolysis. To solve this problem, a variety of exhaust system variants with treatment lines, mixers, evaporators, and hydrolysis catalysts have already been proposed.Despite the numerous proposed solutions, there is still a need for improvement with regard to the treatment of reducing agents introduced into the exhaust gas, particularly in liquid form, in the sense mentioned above.

[0003] US 2006 / 0 218 902 A1 discloses a fuel addition and treatment system in which a liquid fuel is added to the exhaust gas emitted by a vehicle's internal combustion engine. This system includes an injector and a mixing tube.

[0004] Furthermore, DE 42 03 807 A1 describes a device for catalytic nitrogen oxide reduction. This device contains a hydrolysis catalyst with fine flow channels for uniform distribution of the urea solution.

[0005] The object of the invention is therefore to provide a device with which advantageous introduction of reducing agent and the best possible treatment of reducing agent introduced into the exhaust gas of an internal combustion engine is possible.

[0006] This object is achieved by a reducing agent addition and treatment system having the features of claim 1.

[0007] The reducing agent addition and processing system according to the invention for adding a liquid reducing agent to exhaust gas emitted by an internal combustion engine of the motor vehicle and for processing the added reducing agent in the exhaust gas comprises an injector assigned to a reducing agent metering unit, which can spray a reducing agent spray jet into the exhaust gas, a mixing tube arranged in an exhaust tract of the internal combustion engine with a first and a second axial mixing tube end, and a funnel element arranged in the region of the first mixing tube end on or in the mixing tube, which widens conically in the direction from the first mixing tube end to the second mixing tube end with a predetermined widening angle.The mixing tube and the funnel element are designed as rotating hollow bodies, each with a perforated outer surface, with the perforation of the mixing tube being at least predominantly larger than the perforation of the funnel element. The funnel element has a passage opening at its end associated with the first mixing tube end, and the reducing agent dosing unit is arranged such that the injector can spray the reducing agent spray jet through the passage opening into the interior of the funnel element.

[0008] The spray jet sprayed into the funnel element by the injector can optimally develop into a fine spray mist, avoiding wall wetting, due to the exhaust gas inflow into the funnel element at a comparatively high speed, enabled by the perforation of the funnel element. Further transport toward the second mixing tube end is possible, while wall wetting is also at least largely avoided due to the larger perforation of the mixing tube and the resulting exhaust gas inflow into the mixing tube interior at a comparatively low speed. This creates a treatment section that enables the formation of a fine spray of reducing agent droplets, which can advantageously evaporate increasingly easily during their transport path.When exiting the second mixing tube end, the reducing agent is therefore typically at least predominantly evaporated and a homogeneous distribution over the entire exhaust pipe cross-section is possible.

[0009] The injector has an end-side injector tip, wherein the injector tip and the passage opening of the funnel element each have an at least approximately circular circumferential contour and an outlet opening for the reducing agent is arranged at least approximately centrally on the injector tip and the outlet opening and a center point of the passage opening lie at least approximately on the axis of rotation of the funnel element and the injector tip is arranged opposite the funnel element at a short distance from the passage opening in such a way that an annular gap is formed by the injector tip and a lateral surface area of ​​the funnel element surrounding the passage opening, through which annular gap exhaust gas can flow into the interior of the funnel element.Due to the formation of the annular gap, exhaust gas entering the interior of the funnel element through this can capture the spray jet emitted by the injector from behind and transport it in an axial direction with as little turbulence or backflow as possible. Furthermore, this embodiment avoids the formation of flow dead zones, wall wetting and the resulting deposits. It is particularly advantageous if, in a further embodiment of the invention, the annular gap is dimensioned such that the exhaust gas flowing through the annular gap into the funnel element has an entry velocity that is higher than a velocity at which the injector sprays the reducing agent spray jet, at least at operating points of the internal combustion engine above partial load.This enables a particularly effective formation of a fine spray by crushing the reducing agent droplets and improves the evaporation behavior.

[0010] In one embodiment of the invention, the rotational axes of the mixing tube and the funnel element coincide at least approximately, and the passage opening is arranged at least approximately centrally along the rotational axis. This axially aligned, rotationally symmetrical arrangement enables a centered spraying of the reducing agent into the funnel element, which helps prevent wall wetting.

[0011] Furthermore, it has proven particularly advantageous if, in a further embodiment of the invention, the injector can spray a reducing agent spray jet that widens at least approximately conically into the exhaust gas, with an expansion angle of the reducing agent spray jet at least approximately corresponding to the expansion angle of the funnel element. This enables a uniform, reducing dispersion of the reducing agent droplets while avoiding wetting of the inner surface of the funnel element and creating uniform, undisturbed flow conditions.

[0012] In a further embodiment of the invention, the expansion angle of the funnel element is in the range between 20 degrees and 70 degrees, in particular between 30 degrees and 60 degrees. This configuration has proven to be particularly aerodynamic and advantageous for reducing agent processing.

[0013] In a further embodiment of the invention, the perforation of the funnel element provides that exhaust gas flowing into the funnel element has an at least approximately vertical orientation with respect to the envelope surface of the reducing agent spray cone of the reducing agent spray jet emitted by the injector. This enables the formation of an exhaust gas cushion that shields the inner wall of the funnel element, further reducing the risk of wall wetting and promoting the comminution of the reducing agent droplets.

[0014] In a further embodiment of the invention, the funnel element is arranged at least largely inside the mixing tube, with the funnel element resting at its flared end all the way around the inside of the lateral surface of the mixing tube or being connected to the mixing tube in a material-to-material and / or form-fitting manner. This ensures a stable, particularly compact arrangement of the mixing tube and funnel element relative to one another.

[0015] In a further embodiment of the invention, an exhaust gas guide element is provided which directs a portion of the exhaust gas flowing in the direction of the first mixing tube end onto the perforated outer surface of the funnel element and directs a second portion towards a part of the perforated outer surface of the mixing tube (7) that is downstream of the funnel element (10). This enables uniform flow conditions that are largely independent of the flow velocity. The exhaust gas portion directed in the direction of the perforated outer surface of the funnel element and flowing at least partially into the interior of the funnel element promotes the formation of a fine reducing agent spray. The exhaust gas portion directed in the direction of the outer surface of the mixing tube and flowing at least partially into the interior of the mixing tube causes the reducing agent to be transported further.

[0016] In a further embodiment of the invention, an elbow-shaped exhaust pipe element is provided for guiding the exhaust gases, having a first leg on the inflow side and a second leg on the outflow side adjoining the first leg, wherein the mixing tube extends from a deflection region from the first leg to the second leg into the second leg and is arranged concentrically to the second leg. This enables a particularly favorable and compact arrangement of the entire reducing agent addition and treatment system. To simplify the connection to the exhaust tract, it is advantageously further provided that a first separation point for attaching an exhaust gas supply pipe is provided at an inflow-side end of the first leg and a second separation point for connecting an exhaust gas discharge pipe is provided at the outflow-side end of the second leg.According to a further advantageous embodiment of the invention, the mixing tube extends beyond the second separation point from the elbow-shaped exhaust pipe element. This avoids a detrimental flow effect of the separation point on the reducing agent preparation, since the mixing tube shields the separation point.

[0017] In a further embodiment of the invention, a vortex-forming baffle component is provided for the exhaust gas supply pipe. This enables an improved even distribution of the exhaust gas flow with respect to the cross-section of the exhaust gas supply pipe.

[0018] It has proven particularly advantageous, in a further embodiment of the invention, for the elbow-shaped exhaust pipe element to have a thermal insulation coating on the outside, at least in sections. This largely prevents or at least reduces heat losses that hinder the evaporation of the reducing agent in the area of ​​the exhaust tract critical for reducing agent preparation.

[0019] In a further embodiment of the invention, a flange component is provided to which the mixing tube and the reducing agent dosing unit are fastened and to which, furthermore, at least one cooling plate is fastened on the outside with respect to the exhaust tract for dissipating heat from the flange component to the environment. As a result of this design, a reduction in the temperature load on the dosing unit as a whole and in particular on the injector is made possible. It is particularly advantageous if a first and a second cooling plate are provided, wherein the first and the second cooling plates are in heat transfer contact with one another via a heat transfer plate and are kept at a distance from one another by the heat transfer plate.This enables a further improvement in heat dissipation, whereby the heat transfer plate also enables a targeted shaping of the developing temperature gradient and thus high temperatures can be kept away from critical areas in this regard.

[0020] Further advantages, features, and details of the invention will become apparent from the following description of preferred embodiments and from the drawings. The features and feature combinations mentioned above in the description, as well as the features and feature combinations mentioned below in the figure descriptions and / or shown alone in the figures, can be used not only in the respective combinations specified, but also in other combinations or on their own, without departing from the scope of the invention. The figures show: Fig. 1 a sectional view of a preferred embodiment of the reducing agent addition and preparation system according to the invention, Fig. 2 a section of the reducing agent addition and treatment system according to Fig. 1 and Fig. 3 a perspective view of a cooling plate arrangement for cooling the dosing unit.

[0021] The following are based on the Fig. 1 and Fig. 2 an advantageous and preferred embodiment of the reducing agent addition and preparation system according to the invention and its properties and functions are described in more detail, wherein the same components are assigned the same reference numerals. Fig. 1 shows a sectional view of the reducing agent addition and preparation system 1, while Fig. 2 shows a perspective view of a section that specifically shows the conditions at an injector 3 of the reducing agent addition and preparation system 1. The Fig. 1 and Fig. The reducing agent addition and treatment system 1 shown in Figure 2 serves in the present case for the introduction, distribution, and evaporation of aqueous urea solution into the exhaust tract of a motor vehicle internal combustion engine, in particular a diesel engine of a commercial vehicle. However, the reducing agent addition and treatment system 1 is also considered suitable for the introduction and treatment of other liquid reducing agents, such as mineral oil fuel, in particular diesel fuel.

[0022] According to the presentation in Fig. 1, the reducing agent addition and treatment system 1 comprises a knee-shaped exhaust pipe element 18, to whose first leg 21 on the exhaust gas inlet side an exhaust gas supply pipe 24 is connected at a first separation point 23. An exhaust gas discharge pipe 26 is connected to a second leg 22 on the exhaust gas outlet side at a second separation point 25. The exhaust pipe element 18 is preferably constructed from two half-shells, which facilitates assembly.

[0023] The reducing agent addition and treatment system 1 receives exhaust gas containing nitrogen oxides from a diesel engine (not shown), into which the urea solution is injected. Exhaust gas enriched with urea solution leaves the reducing agent addition and treatment system 1 through the exhaust gas discharge pipe 26 and is fed to a downstream SCR catalyst for selective catalytic nitrogen oxide reduction using ammonia released from the urea by thermolysis and / or hydrolysis, which is also not shown in detail. A main exhaust gas flow direction is indicated by arrows 16. The reducing agent addition and treatment system 1 advantageously adds, distributes, and evaporates the urea solution, which is explained in more detail below with general reference to treatment.It is understood that the exhaust gas purification system of the diesel engine may have, in addition to the SCR catalyst, further catalytic and / or filter-effective exhaust gas purification elements upstream and / or downstream.

[0024] For the metered addition of the urea solution to the exhaust gas, a metering unit 2 with an injector 3 is provided, wherein the injector 3 can deliver a conical spray jet 6 of the urea solution, which is particularly useful in Fig. 2. For the preparation, a mixing tube 7 designed as a hollow cylinder with a circular cross-section is provided, the outer surface of which is provided with a large-area perforation 11. The mixing tube 7 extends from a first end 8 arranged near the injector 3 in the transition area from the first leg 21 to the second leg 22 beyond the second separation point 25 to its second end 9. It runs concentrically with respect to an axis 14 and with a comparatively small radial distance to the second leg 22 of the bent exhaust line element 18. The mixing tube 7 is carried by a flange component 29, to which the metering unit 2 is also fastened. The fastening of the metering unit 2 to the flange component 29 is described further below with additional reference to Fig. 3 is explained in more detail.

[0025] Another key component for the preparation of the urea solution is a funnel element 10 arranged in the area of ​​the first mixing tube end 8 inside the mixing tube, which also has a perforated outer surface. The funnel element 10 is designed as a rotating body and preferably arranged such that it shares the rotation axis 14 with the mixing tube 7. In this case, the funnel element 10 is firmly connected to the mixing tube 7 at its widened end, for example by welding. This divides the mixing tube 7 into an upstream part facing the injector 3 or the dosing unit 2, and a downstream part with a completely free outflow cross-section. At its tapered end, located a short distance away from the injector 3, the funnel element 10 has a passage opening 13 through which the injector 3 can spray the spray jet 6 into the interior of the funnel element 10.For this purpose, the injector 3 is advantageously aligned with the axis 14, wherein its outlet opening 5 arranged on the injector tip 4 is arranged on the axis 14 and thus centrally with respect to the passage opening 13 of the funnel element 10, which can be seen in particular from . Fig. 2 becomes clear.

[0026] The particularly efficient treatment of urea solution supplied to the exhaust gas by means of the injector 3 is now carried out by the following with further reference to Fig. 1 and Fig. 2 measures explained in more detail and working together in a synergistic manner.

[0027] First, a largely uniform distribution of exhaust gas flowing into the exhaust gas supply pipe 24 across the pipe cross-section is achieved by a baffle component 27 with a large baffle opening. The baffle opening is preferably more than 90%, particularly preferably more than 95%, of the pipe cross-section. This keeps pressure loss low while still achieving good, even exhaust gas distribution through turbulence at the baffle edge.

[0028] Furthermore, an exhaust gas guide element 17 extending in the longitudinal direction of the exhaust gas supply pipe 24 achieves a division of the exhaust gas flow in that part of the exhaust gas flow is directed onto the perforated outer surface of the funnel element 10 and the other part of the exhaust gas flow is directed towards the part of the large-area perforation 11 of the mixing pipe 7 arranged downstream thereof. For this purpose, the exhaust gas guide element 17 extends from a point upstream of the first separation point 23 of the exhaust gas line element 18 to close to the mixing pipe 7 and preferably extends at least approximately over the entire radial extent of the first leg 21 of the exhaust gas line element 18 or of the exhaust gas supply pipe 24 and encloses the mixing pipe 7 at the end at a small distance in an approximately semicircular manner.

[0029] Exhaust gas directed toward the perforated outer surface of the funnel element 10 flows through the large-area perforation 11 of the mixing tube 7 present there, largely into the interior of the upstream part of the mixing tube 7 formed by the funnel element 10, where it encounters the perforated outer surface of the funnel element 10. In order to enable the most evenly distributed flow possible all around, a first pocket-shaped bulge 19 is provided for the exhaust pipe element 18 in the transition from the first leg 21 to the second leg 22. This bulge 19 increases the radial distance between the mixing tube 7 and the exhaust pipe element 18 in the arrangement region of the funnel element 10, and a more uniform inflow conditions are achieved all around. An increase in diameter due to the first pocket-shaped bulge 19 is preferably approximately 10%.

[0030] The distribution of exhaust gas flowing into the funnel element 10 and the downstream part of the mixing tube 7, respectively, in terms of quantity and flow velocity, is determined primarily by the perforations 11, 12 of the mixing tube 7 and the funnel element 10, respectively. Preferably, the perforations 11 of the mixing tube 7 are large-area, at least predominantly uniform, and designed in the form of elongated holes extending in the circumferential direction. The open portion of the mixing tube surface area is preferably more than 70%, particularly preferably more than 80%. This enables, on the one hand, a low-turbulence exhaust gas flow into the mixing tube interior and a transport of any urea present therein in the axial direction.

[0031] It is particularly preferred if slightly smaller perforations are provided all around the mixing tube 7 directly adjacent to the contact area of ​​the funnel element 10. This contributes to stabilizing the position of the spray jet cone in the central area of ​​the mixing tube 7. On the other hand, a portion of exhaust gas flowing around the mixing tube 7 keeps the urea solution away from the wall of the exhaust line element 18, in particular its second leg 22, by forming an exhaust gas cushion. The mixing tube 7 can thus assume a guiding and conducting function for exhaust gas enriched with urea solution. For this purpose, the diameter of the mixing tube 7 is approximately two-thirds of the diameter of the second leg 22 of the exhaust line element 18.

[0032] To even out the flow, in particular to enable the most uniform exhaust gas flow possible into the mixing tube area located behind the funnel element 10, an approximately circumferential second pocket-shaped bulge 20 of the second leg of the exhaust pipe element 18 is provided adjacent to the first pocket-shaped bulge 19. This also reduces pressure losses. In particular, a reduction in back pressure at the bend point of the exhaust pipe element 18 can be achieved due to the deflection of the main exhaust gas flow direction 16 occurring in the exhaust pipe element 18. An increase in diameter due to the second pocket-shaped bulge 20 is preferably also approximately 10%.

[0033] Due to the perforation 12 of the funnel element 10, which is significantly smaller in area than the mixing tube 7, exhaust gas enters the interior of the funnel element 10 at a comparatively high speed. This results in a fragmentation of the reducing agent spray 6 sprayed by the injector 3 through the passage opening 13 into the interior of the funnel element 10, thus achieving fine distribution. Furthermore, the formation of a pressure cushion applied internally to the outer surface of the funnel element 10 is possible, whereby wetting thereof can be effectively prevented. For this purpose, the open portion of the outer surface of the funnel element 10 is preferably less than 30%, particularly preferably less than 20%. In a particularly preferred embodiment, the perforation 12 of the funnel element 10 is formed approximately uniformly by approximately circular holes with a diameter between 2 mm and 6 mm, preferably between 3 mm and 5 mm.

[0034] Exhaust gas entering the interior of the funnel element 10 through the perforation holes 12 of the mixing tube 10 preferably strikes the reducing agent spray cone 6 forming inside the funnel element 10 approximately perpendicularly. To enable the injector 3 to spray urea solution into the interior of the funnel element 10, a through-opening 13 is arranged at the tapered end of the funnel element 10, centrally located at a short distance from the injector tip 4. The distance between the injector tip 4 and the plane of the through-opening 13 is preferably approximately half to one-third of the injector diameter. The through-opening 13 is preferably circular with a diameter that approximately corresponds to the injector diameter and is approximately 15 mm. The tapered end of the funnel element 10 is arranged approximately in the region of the first mixing tube end 8, at which the mixing tube 7 is connected all around to the flange component 29.The injector 3 penetrates the flange component 29, with the injector tip 4 being approximately flush with the flange component 29. The spray jet 6 emitted by the injector 3 can thus enter directly into the interior of the funnel element 10. Preferably, the injector 3 emits the spray jet 6 at a discharge pressure of approximately 5 bar to 12 bar, particularly preferably at a discharge pressure of approximately 10 bar, such that at least approximately a full cone is formed with an opening angle α that approximately corresponds to the opening angle of the funnel element 10. The exit velocity of the urea solution is approximately 15 m / s, whereby larger reducing agent droplets are carried comparatively far into the interior of the funnel element 10 or beyond, where they can break down into smaller droplets, thereby forming an overall fine spray.

[0035] The injector tip 4 and the area of ​​the lateral surface of the funnel element 10 surrounding the passage opening 13 form an annular gap 15 through which exhaust gas can enter the funnel element 10 after being deflected by approximately 90 degrees in an approximately axial direction. The annular gap 15 is dimensioned by the arrangement of the injector tip 4 and funnel element 10 and by the size of the passage opening 13 and injector tip 4 such that, at least above partial load operation of the diesel engine, an inflow velocity of exhaust gas flowing into the funnel element 10 via the annular gap 15 results which is greater than the exit velocity of the urea solution from the injector 3. An exhaust gas inflow velocity of more than 15 m / s is preferably achieved in load ranges with more than 20% of the nominal load of the diesel engine.Preferably, in the predominant load range of the diesel engine, at least in the interior region of the funnel element 10, an exhaust gas velocity is present that exceeds the initial velocity of the reducing agent spray jet 6. This promotes the fragmentation of larger reducing agent droplets and the formation of the finest possible spray. A general further advantage of the exhaust gas entering the funnel element 10 via the annular gap 15 is its effect on the transport of the reducing agent spray jet in the axial direction. Furthermore, as a result of the essentially axial exhaust gas flow, which captures the reducing agent spray jet at an early stage of its formation, recirculation of the reducing agent and flow dead zones are avoided, particularly in the tapered region of the funnel element 10.In order to improve the inflow conditions of exhaust gas via the annular gap 15 into the interior of the funnel element 10, a chamfer of the injector tip 4 is preferably provided.

[0036] As a result of the measures described, a particularly effective and at least almost deposit-free treatment and rapid evaporation over short distances of urea solution added to the exhaust gas by means of the injector 3 are possible. In order to avoid as far as possible undesirable deposits on the injector tip 4, which are particularly favored by elevated temperatures, the measures explained in more detail below are provided for effective heat dissipation from the flange component 29 exposed to the hot exhaust gas. Reference is made to the Fig. 2 and Fig. 3 taken, where in Fig. 3 specifically shows a cooling plate arrangement for cooling and fastening the dosing unit 2.

[0037] The Fig. 3 comprises a first cooling plate 30 and a second cooling plate 31, which are mounted flat on top of one another with a heat transfer plate 32 interposed. The dosing unit 2 is fastened directly to the first cooling plate 30 by means of screw connections 34, which in this case are designed as stud bolts firmly connected to the first cooling plate. The first cooling plate 30 therefore not only provides a cooling surface, but also has a supporting function. The cooling plate arrangement, i.e. the first and second cooling plates 30, 31 and the heat transfer plate 32, are firmly fastened to the flange component 29 by screws 35. For fastening, the screws 35 are inserted through corresponding through-openings 36 in the first and second cooling plates 30, 31 and in the heat transfer plate 32 and screwed into the flange component 29.Heat is thus transferred from the flange component 29, which is exposed to the hot exhaust gas, primarily via the screws 35 to the cooling plate arrangement. Particularly effective cooling, while avoiding overheating of the dosing unit 2, is achieved by the heat transfer plate 32 distributing the heat transferred from the flange component 29 to the first cooling plate 30 and also to the second cooling plate 31, thereby almost doubling the cooling effect compared to a single cooling plate. The heat transfer plate 32 maintains a distance between the two cooling plates 30 and 31, thereby improving convective heat dissipation to the environment. In addition, the special tab-shaped design of the heat transfer plate 32 ensures targeted heat dissipation to non-critical areas of the cooling plates 30, 31.As a result of the effective heat dissipation enabled by this design of the cooling plate arrangement, the temperature of both the dosing unit 2 and the injector can be kept comparatively low.

[0038] It should also be noted that a Fig. 1, the frame bracket 37, which is only partially visible or shown, enables attachment of the reducing agent addition and treatment system 1 to different exhaust systems. The frame bracket 37 also enables mechanical fixation of the exhaust line or pipe elements 18, 24, 26 joined at the separation points 23, 25. List of reference symbols 1 reducing agent addition and treatment system 2 Reducing agent dosing unit 3 Injector 4 Injector tip 5 Injector outlet opening 6 Reducing agent spray jet 7 Mixing tube 8 first mixing tube end 9 second mixing tube end 10 funnel element 11 Mixing tube perforation 12 Funnel element perforation 13 Passage opening funnel element 14 Rotation axis 15 Annular gap 16 Arrow exhaust gas flow α Spray jet expansion angle 17 Exhaust guide element 18 Exhaust pipe element 19 first pocket-shaped bulge 20 second pocket-shaped bulge 21 first leg of exhaust pipe element 22 second leg of exhaust pipe element 23 first separation point 24 Exhaust gas supply pipe 25 second separation point 26 Exhaust gas discharge pipe 27 Aperture component 28 Thermal insulation sheathing 29 Flange component 30 first cooling plate 31 second cooling plate 32 heat transfer plate 34 Screw connection for dosing unit 35 screws 36 through openings 37 Frame bracket

Claims

[1] Reducing agent addition and treatment system (1) of a motor vehicle, for adding a liquid reducing agent to exhaust gas emitted by an internal combustion engine of the motor vehicle and for treating the added reducing agent in the exhaust gas, comprising - an injector (3) associated with a reducing agent dosing unit (2) which can spray a reducing agent spray jet (6) into the exhaust gas, - a mixing tube (7) arranged in an exhaust tract of the internal combustion engine with a first and a second axial mixing tube end (8, 9), and - a funnel element (10) arranged in the region of the first mixing tube end (8) on or in the mixing tube (7) and widening conically in the direction from the first mixing tube end (8) to the second mixing tube end (9) with a predetermined widening angle, wherein - the mixing tube (7) and the funnel element (10) are designed as rotary hollow bodies each with a perforated outer surface and the perforation (11) of the mixing tube (7) is at least predominantly larger in area than the perforation (12) of the funnel element (10), - the funnel element (10) has a passage opening (13) at its end associated with the first mixing tube end (8), and - the reducing agent dosing unit (2) is arranged so that the injector (3) can spray the reducing agent spray jet (6) through the passage opening (13) into the interior of the funnel element (10), characterized byin that the injector (3) has an end-side injector tip (4), wherein the injector tip (4) and the passage opening (13) of the funnel element (10) each have an at least approximately circular circumferential contour and an outlet opening (5) for the reducing agent is arranged at least approximately centrally on the injector tip (4), and the outlet opening (5) and a center point of the passage opening (13) lie at least approximately on the axis of rotation (14) of the funnel element (10), and the injector tip (4) is arranged opposite the funnel element (10) at a short distance from the passage opening (13) in such a way that an annular gap (15) is formed by the injector tip (4) and a lateral surface area of ​​the funnel element (10) surrounding the passage opening (13), through which annular gap (15) exhaust gas can flow into the interior of the funnel element (10). [2] Reducing agent addition and treatment system according to claim 1, characterized bythat the axes of rotation (14) of the mixing tube (7) and the funnel element (10) coincide at least approximately with one another and the passage opening (13) is arranged at least approximately centrally to the axis of rotation. [3] Reducing agent addition and treatment system according to claim 1 or 2, characterized by that the annular gap (15) is dimensioned such that the exhaust gas flowing through the annular gap (15) into the funnel element (10) has an inlet speed, at least at operating points of the internal combustion engine above a partial load, which is above a speed at which the injector (3) sprays the reducing agent spray jet (6). [4] Reducing agent addition and treatment system according to one of claims 1 to 3, characterized bythat the injector (3) can spray an at least approximately conically widening reducing agent spray jet (6) into the exhaust gas, wherein an expansion angle (α) of the reducing agent spray jet (6) corresponds at least approximately to the expansion angle of the funnel element (10). [5] Reducing agent addition and treatment system according to one of claims 1 to 4, characterized by that the expansion angle (α) of the funnel element (10) is in the range between 20 degrees and 70 degrees, in particular between 30 degrees and 60 degrees. [6] Reducing agent addition and treatment system according to one of claims 1 to 5, characterized by that exhaust gas flowing into the funnel element (10) through the perforation (12) of the funnel element (10) has an at least approximately vertical orientation with respect to an enveloping surface of the reducing agent spray jet cone of the reducing agent spray jet (6) sprayed by the injector (3). [7] Reducing agent addition and treatment system according to one of claims 1 to 6, characterized by that the funnel element (10) is arranged at least largely in the interior of the mixing tube, wherein the funnel element (10) rests at its widened end all around on the inside against the lateral surface of the mixing tube (7) or is connected to the mixing tube (7) in a material and / or form-fitting manner. [8] Reducing agent addition and treatment system according to one of claims 1 to 7, characterized by that an exhaust gas guide element (17) is provided which directs a part of the exhaust gas flowing in the direction of the first mixing tube end (8) onto the perforated outer surface of the funnel element (10) and directs a second part in the direction of a part of the perforated outer surface of the mixing tube (7) which is downstream with respect to the funnel element (10). [9] Reducing agent addition and treatment system according to one of claims 1 to 8, characterized bythat an exhaust pipe element (18) bent in a knee shape is provided for guiding the exhaust gas, with a first leg (21) on the inflow side and a second leg (22) on the outflow side adjoining the first leg (21), wherein the mixing pipe (7) extends from a deflection region from the first leg (21) to the second leg (22) into the second leg (22) and is arranged concentrically to the second leg (22). [10] Reducing agent addition and treatment system according to claim 9, characterized by that a first separation point (23) for attaching an exhaust gas supply pipe (24) is provided at an inflow-side end of the first leg (21), and a second separation point (25) for connecting an exhaust gas discharge pipe (26) is provided at the outflow-side end of the second leg (22). [11] Reducing agent addition and treatment system according to claim 10, characterized bythat the mixing pipe (7) extends beyond the second separation point (25) from the knee-shaped exhaust pipe element (18). [12] Reducing agent addition and treatment system according to claim 10 or 11, characterized by that a vortex-forming aperture component (27) is provided for the exhaust gas supply pipe (24). [13] Reducing agent addition and treatment system according to one of claims 9 to 12, characterized by that the knee-shaped exhaust pipe element (18) has a heat insulation sheath (28) on the outside at least in sections. [14] Reducing agent addition and treatment system according to one of claims 1 to 13, characterized by that a flange component (29) is provided, to which the mixing tube (7) and the reducing agent metering unit (2) are fastened and to which at least one cooling plate (30; 31) for dissipating heat from the flange component (29) to the environment is fastened on the outside with respect to the exhaust tract. [15] Reducing agent addition and treatment system according to claim 14, characterized by that a first and a second cooling plate (30, 31) are provided, wherein the first and the second cooling plate (30, 31) are in heat transfer contact with one another via a heat transfer plate (32) and are kept at a distance from one another by the heat transfer plate (32).

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