DE102020212845A1 - Device for exhaust aftertreatment - Google Patents

Abstract

The invention relates to a device (1, 10, 20, 40) for the aftertreatment of exhaust gases from an internal combustion engine, having a housing (10, 20, 40) through which an exhaust gas flow can flow from an inlet side to an outlet side along a flow path, wherein at least one of the following exhaust gas aftertreatment components (2, 6, 21, 30) is arranged within the flow path in the housing (10, 20, 40), a catalytic converter, a particle filter, a heating device, a muffler, a hydrocarbon trap, a nitrogen oxide trap, an evaporation device or an injection device for Injection of a fluid into an exhaust gas flow path, the housing (10, 20, 40) forming the spatial boundary of the flow path. The invention also relates to a motor vehicle with a device according to the invention.

Description

technical field

The invention relates to a device for exhaust gas aftertreatment of exhaust gases from an internal combustion engine, with a housing through which an exhaust gas flow can flow from an inlet side to an outlet side along a flow path, with at least one of the following exhaust gas aftertreatment components being arranged within the flow path in the housing, a catalytic converter, a particle filter, a heating device, a silencer, a hydrocarbon trap, a nitrogen oxide trap, an evaporation device or an injection device for injecting a fluid into an exhaust gas-carrying flow path. The invention also relates to a motor vehicle with a device according to the invention.

State of the art

Devices for exhaust aftertreatment, such as catalytic converters in particular, are regularly installed very close to the engine or in a tunnel-shaped area on the underbody of the vehicle.

A disadvantage of the devices for exhaust gas aftertreatment, which are known in the prior art, is in particular that these devices are not optimally adapted to new vehicle groups, such as hybrid vehicles. In particular, new hybrid vehicles do not have a tunnel-like structure on the underbody that leads from the internal combustion engine under the vehicle floor to the end of the vehicle. Due to the increasing electrification of vehicles, more and more space is required for accommodating the energy storage devices. For this purpose, the floor assembly of the vehicles has individual box-like segments that are fitted with battery cells depending on the planned size of the energy storage system. With the increasing spread of such highly electrified vehicles, the demands on the device that is still necessary for exhaust gas aftertreatment are becoming ever greater. The primary goal is to make the exhaust aftertreatment as compact as possible and to integrate it into the vehicle and in particular into the box-like segments in the underbody of the vehicle without further adjustments to the vehicle structure.

Presentation of the invention, task, solution, advantages

It is therefore the object of the present invention to create a device for exhaust gas aftertreatment which has the most compact possible design and enables integration into standardized box-like segments in electrified vehicles, in particular in hybrid vehicles. In addition, it is the object of the present invention to create a motor vehicle with a device according to the invention.

The object with regard to the device for exhaust gas aftertreatment is achieved by a device for exhaust gas aftertreatment having the features of claim 1 .

One exemplary embodiment of the invention relates to a device for exhaust gas aftertreatment of exhaust gases from an internal combustion engine, having a housing through which an exhaust gas flow can flow from an inlet side to an outlet side along a flow path, with at least one of the following exhaust gas aftertreatment components being arranged within the flow path in the housing, a catalytic converter, a Particulate filter, a heating device, a silencer, a hydrocarbon trap, a nitrogen oxide trap, an evaporation device or an injection device for injecting a fluid into an exhaust gas-carrying flow path, the housing forming the spatial boundary of the flow path.

The device can have any number, but at least one component for exhaust gas aftertreatment. The components known from the prior art for exhaust aftertreatment can be adapted to the desired installation situation and integrated into the housing. These include, for example, diesel oxidation catalytic converters (DOC), diesel particulate filters (DPF), catalytic converters for selective catalytic reduction (SCR), for example an aqueous urea solution, three-way catalytic converters (TWC), gasoline particulate filters (GPF), nitrogen oxide traps (NSK), or adsorbers for storage excess nitrogen oxides, for example when driving with a lean mixture, and/or hydrocarbons, which are formed during a cold start or when driving with a rich mixture.

According to the invention, the housing forms the spatial delimitation of the flow path. The flow section means, in particular, the respective flow path through which the exhaust gas flows. The components for exhaust gas aftertreatment, which are preferably formed by metallic honeycomb bodies with a plurality of flow channels through which flow can flow, are arranged within the flow path.

In contrast to systems known from the prior art, the exhaust gas is not routed from one exhaust gas aftertreatment component to the next by means of a pipeline. The exhaust gas routing takes place completely through the housing of the device and the components for exhaust gas aftertreatment arranged therein.

In this case, the housing is either a separate component or part of the underbody of the vehicle, into which the device is integrated. Highly electrified vehicles, such as modern hybrid vehicles, have a floor assembly that primarily accommodates the power electronics and the energy storage. For this purpose, the floor assembly often has a sandwich construction, with box-like areas being formed between the upper and lower sandwich floor. As a result, the vehicles have a modular design that can be used according to the respective vehicle model. In a vehicle without an internal combustion engine, the box-like areas can be completely occupied by power electronics and battery cells, while in a hybrid vehicle at least some of these box-like areas are used to accommodate the exhaust gas aftertreatment device.

In order to enable the device for exhaust gas aftertreatment to be easily integrated into such a floor assembly, the device should be designed to fit these box-like areas. Depending on the size of the device, several box-like areas arranged adjacent to one another can also be connected to one another in order to increase the available installation space.

Unless the device is arranged in its own additional housing, the spatial delimitation of the box-like area which accommodates the device according to the invention forms the spatial delimitation of the flow path for the exhaust gas, ie the housing.

It is particularly advantageous if the exhaust gas flow is routed within the device between the exhaust gas aftertreatment components through the housing. The flow line is formed within the device, in particular between the components, by empty spaces arranged in the housing, which are upstream and downstream of the respective inflow cross sections and outflow cross sections of the individual components.

In the simplest case, the voids can be used to transfer the flow along a main flow direction in one of the three spatial directions. However, the empty spaces can advantageously also be designed in such a way that the flow is passed on along several spatial directions. It is also possible for the exhaust gas flow to be divided up into a number of components through the empty spaces.

For this purpose, baffle plates can be provided at the edges of the empty spaces, which facilitate the flow guidance into the next exhaust gas components and thus reduce the pressure loss. The flow of exhaust gas can also be divided using baffles.

It is also advantageous if the exhaust gas flow takes place in three dimensions within the device. Depending on the arrangement of the individual components, the main flow direction of the exhaust gas can be in one of the three spatial directions, or in several spatial directions. In particular, several flow deflections can take place one after the other.

A preferred exemplary embodiment is characterized in that the exhaust gas stream can flow into the housing through an inflow device and can flow out of the housing through an outflow device. In particular, diffusers, nozzles, conical tubes with a round or square cross section or metal flexible tubes can be provided here in order to guide the exhaust gas from the internal combustion engine into the housing of the device.

It is also preferable if at least one electrical heating device is provided, which is formed by an electrically heatable honeycomb body. Electrically heatable honeycomb bodies are known in the prior art. They generate heat using the ohmic resistance. At the same time, such honeycomb bodies can also perform an additional function for exhaust gas aftertreatment. Several heating devices can also be arranged within the device in order to ensure optimized heating of the device.

The housing itself and/or individual components can have an electrical insulation layer that limits the current required to heat individual components to these components. In particular, short circuits should be avoided here and the current flow in areas that can be touched by people should be avoided, since there is an increased risk for people, especially in the light of the increased on-board voltages in the area of modern hybrid vehicles.

Electrical bushings for contacting the heating devices and sensors are preferably routed through bores in the housing wall. In particular, the electrical feedthroughs can also be angled, depending on the installation situation.

In addition, it is advantageous if the individual exhaust gas aftertreatment components are formed by honeycomb bodies, the individual honeycomb bodies being stacked on top of one another and/or next to one another within the housing.

The individual honeycomb bodies can be arranged in the housing without being mechanically connected to one another, in which case they are clamped relative to the housing so that they are fixed inside the housing. Alternatively, the honeycomb bodies can be mechanically connected to one another. The honeycomb bodies are preferably soldered to one another. In particular, the honeycomb bodies can be connected to one another at their respective metal foils, which form the outer edge layer. The outermost edge layer of the honeycomb body is regularly formed by a smooth layer which is flow-tight.

Furthermore, it is advantageous if flow-tight metallic plates are arranged between the individual exhaust gas aftertreatment components.

Additional flow-tight plates or thicker metal foils are advantageous in order to generate greater stability of the device. Furthermore, the interior formed in the housing can be further subdivided by the plates in order to form individual receiving areas for the individual components. The plates can run over the entire width, length and/or depth of the housing and thus create a flow-tight subdivision of the housing. Alternatively, however, the plates can also have a shorter extension in each of the directions, so that no flow-tight delimitation is achieved.

It is also expedient if the housing has a cuboid wall, with a likewise cuboid inner tube being arranged inside the wall, as a result of which a tubular flow path with a rectangular cross section is formed inside the housing and an annular flow path with a rectangular cross section, with the annular flow path between the Inner tube and the housing is formed.

A type of ring catalytic converter is thus formed within the box-like area. A deflection area is formed via an empty space, which is formed within the box-like area, so that an overflow from the tubular to the annular flow path is made possible. For this purpose, the inner tube preferably has a shorter extent than the housing, with the deflection chamber being formed in this area.

In addition, it is advantageous if two flow paths through which flow can flow in parallel are formed within the housing, each of the flow paths having at least one exhaust gas aftertreatment component.

In particular, the flow path can have a horizontal division or a vertical division. In an advantageous embodiment, a means for influencing the flow of exhaust gas can be provided. This can be a flap, an adjustable guide element or a valve, for example. The flow of exhaust gas can be distributed over the flow sections formed via such an element. In this way, a time-limited flow through individual flow paths can be achieved, or the exhaust gas volume flow can also be limited within a flow path.

The object with regard to the motor vehicle is solved by a motor vehicle having the features of claim 10 .

One embodiment of the invention relates to a motor vehicle with a device for exhaust gas aftertreatment, the device being arranged within an underbody of the motor vehicle, the underbody having a plurality of spatially separate box-like areas, the device for exhaust gas aftertreatment completely in one or more of these box-like areas is integrated.

A motor vehicle according to the invention has at least one internal combustion engine. This can be used both as a separate drive source and as a stationary generator to generate electricity. The vehicle has an underbody constructed in a sandwich construction, the underbody having a box-like area in which, among other things, the necessary components for electrical operation or for exhaust gas aftertreatment can be accommodated.

By integrating the exhaust aftertreatment components into one of these box-like areas, a compact exhaust system is designed. This eliminates the need for an exhaust gas tunnel on the underbody of the vehicle. The entire device can be thermally insulated so that heat losses and cold start emissions are reduced. With good flow deflection, the pressure loss can be reduced due to the compact design.

Advantageous developments of the present invention are set out in the dependent claims and in described in the following figure description.

character list

• 1 eine schematische Ansicht einer Cat-Box, wobei mehrere Abgasnachbehandlungskomponenten in Reihe hintereinander angeordnet wurden, wobei die Wabenkörper durch das Gehäuse der Cat-Box gehalten sind und der Abgaseintritt durch einen Diffusor und der Abgasaustritt durch eine Düse gebildet ist,
• 2 eine schematische Ansicht einer Cat-Box, wobei der durch ein zentrales Rohr ein sogenannter Ringkatalysator ausgebildet ist, mit einer ringförmigen Strömungsstrecke, einer rohrförmigen Strömungsstrecke und einer Umlenkkammer zum Übergang der Abgasströmung aus der ringförmigen Strömungsstrecke in die Rohrförmige Strömungsstrecke, 3 einen Querschnitt durch die Cat-Box der 2,
• 4 eine schematische Schnittansicht durch eine Cat-Box mit aufeinander gestapelten Abgasnachbehandlungskomponenten, welche entlang einer Raumrichtung versetzt zueinander angeordnet sind und mäanderartig nacheinander durchströmt werden,
• 5 eine schematische Ansicht einer Abgasnachbehandlungskomponente, wobei die Komponente beheizte und nicht beheizte Bereiche aufweist, welche durch Isolationsmittel voneinander elektrisch beabstandet sind, und
• 6 eine perspektivische Ansicht einer Cat-Box mit Blick auf die Gaseintrittsseite und die Gasaustrittsseite.

The invention is explained in detail below using exemplary embodiments with reference to the drawings. In the drawings show:

• 1 a schematic view of a cat box, with several exhaust gas aftertreatment components being arranged in a row one behind the other, with the honeycomb bodies being held by the housing of the cat box and the exhaust gas inlet being formed by a diffuser and the exhaust gas outlet being formed by a nozzle,
• 2 a schematic view of a cat box, in which a so-called ring catalyst is formed by a central pipe, with an annular flow section, a tubular flow section and a deflection chamber for the transition of the exhaust gas flow from the annular flow section into the tubular flow section, 3 a cross section through the cat box of 2 ,
• 4 a schematic sectional view through a cat box with exhaust gas aftertreatment components stacked on top of one another, which are arranged offset to one another along a spatial direction and are flown through one after the other in a meandering manner,
• 5 a schematic view of an exhaust gas aftertreatment component, the component having heated and unheated regions which are electrically spaced apart from one another by insulating means, and
• 6 a perspective view of a cat box looking at the gas inlet side and the gas outlet side.

Preferred embodiment of the invention

the 1 shows a sectional view of a cat box 1, which is formed by a plurality of series-connected components 2 for exhaust gas aftertreatment within a housing 3. The housing 3 can preferably be formed by a box-like area formed in the underbody of a vehicle or by the walls delimiting the box-like area.

In the example of 1 several honeycomb bodies 2 are shown, through which the flow can flow in succession from the flow inlet 4 to the flow outlet 5 . Electrically heatable honeycomb bodies are identified by the reference numeral 6 . These heatable honeycomb bodies 6 are connected to a voltage source (not shown) by means of electrical bushings 7 routed through the housing 3 .

The flow inlet 4 is formed by a diffuser. The flow outlet 5 is formed by a nozzle.

the 2 shows an alternative embodiment of a device for exhaust gas aftertreatment. The housing 10, which is formed, for example, by the walls of the box-like area, has an inner tube 11, as a result of which the inner volume 12 of the housing 10 is divided into a tubular flow path 13 and an annular flow path 14.

The inner tube 11 has a shorter extent than the housing 10, as a result of which an area 15 is formed into which the inner tube 11 does not protrude. This area 15 is the deflection area in which the exhaust gas flow is deflected from the annular flow path 14 into the tubular flow path 13 .

The housing 10 has a flow inlet 16 which is aligned in a radial direction to the central axis of the inner tube 11 . The flow outlet 17 is formed by a nozzle adjoining the inner tube 11 .

A plurality of different components 18 for exhaust gas aftertreatment can be arranged within the housing 10 . Electrical feedthroughs 19 can be routed from the outside into the ring-shaped flow path 14 or the tubular flow path 13 and contact electrically heatable structures there. The inner tube can also be rectangular in accordance with the cross section of the housing 10, which also creates a rectangular annular flow path.

Electrical bushings 19 and/or sensors 18 can be led into the tubular flow path 13 and/or the ring-shaped flow path 14 .

the 3 shows a sectional view through the device 2 . The inner tube 11 is shown, which is arranged inside the housing 10 . The tubular flow path 14 is formed inside the inner tube 11 . The annular flow path 13 is formed between the inner tube 11 and the housing 10 .

4 shows a sectional view through a housing 20 with a plurality of components 21 for exhaust gas aftertreatment within the housing 20. Exhaust gas can flow through the inlet 24 in the flow in honeycomb body 21 marked with the letter A and flow through it along the direction X in space. The honeycomb body A has a shorter extension along the spatial direction X than the housing 20. This results in the empty space 22, in which the exhaust gas is directed from the honeycomb body A into the honeycomb body B. The flow through the honeycomb body B is counter to the main flow direction of the honeycomb body A.

Another empty space 23 is formed between the housing 20 and the honeycomb body B due to the shorter extension of the honeycomb body B compared to the housing 20 along the spatial direction X, in which the exhaust gas from the honeycomb body B is deflected into the honeycomb body C. Finally, the honeycomb body C is flowed through again in the same main flow direction as the honeycomb body A. From the honeycomb body C, the exhaust gas flows out of the housing 20 at the flow outlet 25 .

The honeycomb bodies A, B and C can extend over the entire depth of the housing 20 in the spatial direction Z, which is the surface normal to the plane of the drawing. Alternatively, a plurality of honeycomb bodies can be arranged one behind the other along the spatial direction Z, through which the flow is then, for example, parallel to the honeycomb bodies A, B and C shown.

The flow line in the housing 20 is achieved entirely through the housing wall and the honeycomb bodies A, B and C. The outer foils in the radial direction of the honeycomb bodies, which are preferably smooth or less structured, fluid-tight foils, limit the flow of exhaust gas to the outside. Together with the housing wall, an effective flow control can be created.

the 5 shows a honeycomb body 30, which can be integrated within a housing or in a box-like area of the underbody of the vehicle. The honeycomb body 30 has two heated areas 31 and an unheated area 32. The heated areas 31 are spaced apart from the unheated area by means of electrically insulating support pins 33. The heated areas 31 can be electrically contacted with electrical feedthroughs.

the 6 shows a sectional view through a housing 40 which is divided by a parting plane 41 into an upper partial volume 42 and a lower partial volume 43 . The parting plane 41 does not extend over the entire length of the housing along the main flow direction 44. This creates an empty space 45 in which the flow through the housing inner wall is deflected from the lower partial volume 43 into the upper partial volume 42.

The parting plane 41 can be formed by the honeycomb body itself. In addition or as an alternative to this, the separating plane 41 can also be formed by a separating plate, which is provided as an additional element for directing the flow.

The different features of the individual exemplary embodiments can also be combined with one another.

The exemplary embodiments 1 until 6 in particular have no restrictive character and serve to clarify the idea of the invention.

Claims (10)

Device (1, 10, 20, 40) for exhaust gas aftertreatment of exhaust gases from an internal combustion engine, with a housing (10, 20, 40) through which an exhaust gas flow can flow from an inlet side to an outlet side along a flow path, wherein at least one of the following exhaust gas aftertreatment components (2, 6, 21, 30) is arranged within the flow path in the housing (10, 20, 40), a catalytic converter, a particle filter, a heating device, a silencer, a hydrocarbon trap, a nitrogen oxide trap, an evaporation device or an injection device for injecting a fluid into an exhaust gas flow path, characterized in that the housing (10, 20, 40) forms the spatial boundary of the flow path. Device (1, 10, 20, 40) according to claim 1 , characterized in that the routing of exhaust gas flow within the device (1, 10, 20, 40) between the exhaust gas after-treatment components (2, 6, 21, 30) is achieved through the housing (10, 20, 40). Device (1, 10, 20, 40) according to one of the preceding claims, characterized in that the exhaust gas flow takes place three-dimensionally within the device (1, 10, 20, 40). Device (1, 10, 20, 40) according to one of the preceding claims, characterized in that the exhaust gas stream can flow into the housing (10, 20, 40) through an inflow device and out of the housing (10, 20, 40) through an outflow device ) can be discharged. Device (1, 10, 20, 40) according to one of the preceding claims, characterized in that at least one electrical heating device (31) is provided, which is formed by an electrically heatable honeycomb body (31). Device (1, 10, 20, 40) according to one of the preceding claims, characterized in that the individual exhaust gas aftertreatment components (2, 6, 21, 30) are formed by honeycomb bodies (6, 30, A, B, C), the individual honeycomb bodies (6, 30, A, B, C) are stacked on top of one another and/or next to one another within the housing (10, 20, 40). Device (1, 10, 20, 40) according to one of the preceding claims, characterized in that flow-tight metal plates are arranged between the individual exhaust gas aftertreatment components (2, 6, 21, 30). Device (1, 10, 20, 40) according to one of the preceding claims, characterized in that the housing (10) has a cuboid wall, with a likewise cuboid inner tube (11) being arranged inside the wall, as a result of which a tubular flow path (13 ) is formed with a rectangular cross section within the housing (10) and an annular flow path (14) with a rectangular cross section, the annular flow path (14) being formed between the inner tube (11) and the housing (10). Device (1, 10, 20, 40) according to one of the preceding claims, characterized in that two parallel flow paths are formed within the housing, each of the flow paths having at least one exhaust gas aftertreatment component. Motor vehicle with a device (1, 10, 20, 40) for exhaust gas aftertreatment according to one of the preceding claims, characterized in that the device (1, 10, 20, 40) is arranged within an underbody of the motor vehicle, the underbody having a plurality of spatially separate box-like areas, wherein the device (1, 10, 20, 40) for exhaust gas aftertreatment is fully integrated in one or more of these box-like areas.

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