Exhaust aftertreatment system for an internal combustion engine as well as internal combustion engine

Abstract

Exhaust aftertreatment system for an internal combustion engine (10), comprising an exhaust system (20) connected to an outlet (14) of the internal combustion engine (10), wherein the exhaust system has an exhaust channel (24) in which, in the direction of flow of exhaust gas through the exhaust channel (24), a turbine (28) of an exhaust gas turbocharger (26) and, downstream of the turbine (28), a particulate filter (32) are arranged, wherein the particulate filter (32) has a filter body (58) and wherein the particulate filter (32) has a housing (86) which tapers conically downstream of the filter body (58) in the form of an outlet funnel (64), characterized in that the outlet funnel (64) branches into a second funnel (66) and a third funnel (68), wherein the second funnel (66) is connected to a low-pressure exhaust gas recirculation (40) and the third funnel (68) to a main channel (50) of the exhaust system (20) is connectedwherein the second funnel (66) carries a filter element (70) at its inlet (88), and wherein the second funnel (66) has an oval inlet geometry at its inlet (88).

Description

[0001] The invention relates to an exhaust aftertreatment system for an internal combustion engine and to an internal combustion engine with an exhaust aftertreatment system according to the preambles of the independent claims.

[0002] Current and increasingly stringent emissions legislation places high demands on raw engine emissions and exhaust aftertreatment in combustion engines. The requirements for further reductions in fuel consumption and the tightening of emissions standards regarding permissible nitrogen oxide emissions pose a challenge for engine developers. In gasoline engines, exhaust gas purification is achieved in the familiar manner via a three-way catalytic converter and additional catalysts upstream and downstream of it. Diesel engines currently employ exhaust aftertreatment systems that include an oxidation catalyst or NOx storage catalyst, a catalyst for the selective catalytic reduction of nitrogen oxides (SCR catalyst), a particulate filter for the separation of soot particles, and, if necessary, further catalysts. Ammonia is preferably used as the reducing agent.Because handling pure ammonia is complex, vehicles typically use a synthetic, aqueous urea solution, which is mixed with the hot exhaust gas stream in a mixing unit upstream of the SCR catalyst. This mixing heats the aqueous urea solution, causing it to release ammonia into the exhaust system. A commercially available aqueous urea solution generally consists of 32.5% urea and 67.5% water.

[0003] To bring the exhaust aftertreatment components up to the required operating temperature after a cold start of the combustion engine, it is desirable to position them as close to the engine as possible. However, this is not always possible due to limited installation space. Therefore, the SCR catalyst and / or the diesel particulate filter are often located further away from the engine in the underbody of the vehicle. Engine-mounted SCR systems are known in which an SCR catalyst and a diesel particulate filter are connected via a funnel. The funnel geometry attempts to reduce back pressure in the exhaust channel, but this requires a comparatively large amount of installation space or necessitates correspondingly small catalysts and / or particulate filters, which requires frequent regeneration and limits the efficiency of the exhaust aftertreatment due to the small volumes.Furthermore, exhaust aftertreatment systems with a close-coupled oxidation catalyst and a close-coupled particulate filter are known from the prior art. To further reduce nitrogen oxide emissions, a low-pressure exhaust gas recirculation system is provided for combustion engines that are turbocharged. This system branches off from the exhaust gas channel downstream of the turbine and feeds into the intake manifold upstream of the turbocharger compressor.

[0004] This involves a conflict of objectives between positioning the exhaust aftertreatment components as close to the engine as possible and achieving the most efficient low-pressure exhaust gas recirculation. In particular, the volume of exhaust gas that can be recirculated via low-pressure recirculation, which serves to reduce NOx emissions during combustion, is limited by the exhaust backpressure in the low-pressure recirculation system.

[0005] A housing shell for an exhaust gas filter is known from DE 10 2006 050 052 A1. The housing shell has a base and a circumferential wall extending transversely to the base, both formed in one piece from a sheet metal part. A connection nozzle for an exhaust gas duct opens into the circumferential wall. The exhaust gas filter known from DE 10 2006 050 052 is pot-shaped or funnel-shaped and rests against the circumferential wall and / or the base, or is supported by the base and / or the circumferential wall, similar to a filter for filter coffee. A disadvantage of this solution, however, is that it requires a comparatively large amount of installation space and is therefore only conditionally suitable for small exhaust gas ducts, especially for exhaust gas recirculation, as it increases the flow resistance and thus makes it more difficult for exhaust gas to flow into the exhaust gas recirculation duct.

[0006] FR 2 892 154 A1 discloses an internal combustion engine with an exhaust aftertreatment system comprising a particulate filter and a low-pressure exhaust gas recirculation system. Downstream of the particulate filter, the exhaust gas channel branches into a first exhaust gas channel connected to the low-pressure exhaust gas recirculation system and a second exhaust gas channel connected to an exhaust gas channel containing a control element for controlling the low-pressure exhaust gas recirculation system.

[0007] From DE 10 2013 212 733 A1, an exhaust aftertreatment system for an internal combustion engine is known, wherein the exhaust aftertreatment system comprises a particulate filter and an exhaust gas recirculation section, wherein a filter element is arranged in the exhaust gas recirculation section. When the particulate filter is regenerated, sufficient heat is supplied to the exhaust gas recirculation section to also regenerate the filter element in the exhaust gas recirculation section.

[0008] From DE 10 2012 208 072 A1, a filter element comprising a filter housing and a filter arranged within the filter housing is known. The filter housing is designed, at least in sections, as a flexible conduit element. The filter element is characterized by the fact that at least one flow guide element for an exhaust gas flow from an internal combustion engine is arranged radially within the flexible conduit element, and this flow guide element is designed to deflect the exhaust gas flow away from the flexible conduit element.

[0009] From FR 2 983 521 A3, an exhaust aftertreatment system for an internal combustion engine is known, wherein a deflection element for an exhaust gas flow of the internal combustion engine is provided downstream of an exhaust aftertreatment component and wherein a branch is provided in this deflection element at which a return exhaust gas flow can be taken from the main exhaust gas flow of the internal combustion engine.

[0010] The subsequently published document DE 10 2017 204 897 A1 describes an internal combustion engine which is connected to an intake manifold at its intake side and to an exhaust system at its exhaust side. The exhaust system includes a catalyst located close to the engine, in particular an oxidation catalyst, and a particulate filter arranged immediately downstream of the catalyst. A low-pressure exhaust gas recirculation system connects the exhaust gas channel to the intake manifold immediately downstream of the particulate filter. The low-pressure exhaust gas recirculation system incorporates an exhaust gas recirculation cooler, which is spatially decoupled from the hot exhaust side and located on a side of the internal combustion engine rotated by 90°.

[0011] The invention is based on the objective of reducing the flow resistance when exhaust gas enters the low-pressure exhaust gas recirculation system and thus reducing the exhaust backpressure in the exhaust aftertreatment system of the internal combustion engine. In particular, the aim is to facilitate the flow of exhaust gas from the exhaust manifold into the low-pressure exhaust gas recirculation system in a compact and space-saving exhaust aftertreatment system.

[0012] The problem is solved by an exhaust aftertreatment system for an internal combustion engine with an exhaust system which is connected to an outlet of the internal combustion engine, wherein the exhaust system has an exhaust duct in which, in the direction of flow of an exhaust gas through the exhaust duct, a turbine of an exhaust gas turbocharger and downstream of the turbine a particulate filter are arranged, wherein the particulate filter has a filter body, wherein the particulate filter has a housing which tapers conically downstream of the filter body in the form of an outlet funnel, wherein the outlet funnel branches into a second funnel and a third funnel, wherein the second funnel is connected to a low-pressure exhaust gas recirculation and the third funnel to a main duct of the exhaust system, and wherein the second funnel carries a filter element at its inlet.The arrangement of the filter element according to the invention reduces the flow resistance when the exhaust gas enters a low-pressure exhaust gas recirculation system of the combustion engine, thus facilitating the flow into the low-pressure exhaust gas recirculation system. This allows a larger volume flow of exhaust gas to be recirculated, advantageously improving the raw emissions of the combustion engine and, in particular, reducing nitrogen oxide emissions. Specifically, the design of the outlet funnel and the second funnel improves the flow towards the filter element, minimizing deflection and flow losses by preventing flow separation.

[0013] The filter element prevents particles and other combustion residues from entering the compressor wheel of the exhaust gas turbocharger and the combustion chambers of the internal combustion engine via the low-pressure exhaust gas recirculation system. In particular, it also prevents fouling of the exhaust gas recirculation channel and / or malfunction of an exhaust gas recirculation valve located within the channel. Additionally, a droplet separator can be incorporated into the filter element to prevent the ingress of liquid exhaust gas components, especially reducing agents for the selective catalytic reduction of nitrogen oxides, into the low-pressure exhaust gas recirculation system.

[0014] The internal combustion engine is preferably designed as a self-igniting internal combustion engine based on the diesel principle, wherein the first catalyst is an oxidation catalyst or a NOx storage catalyst and the particulate filter is designed as a diesel particulate filter (DPF). Alternatively, the internal combustion engine can also be designed as a spark-ignition internal combustion engine based on the Otto principle, wherein the first catalyst is preferably designed as a three-way catalyst and the particulate filter is designed as a gasoline particulate filter (GPF).

[0015] The features listed in the dependent claims enable advantageous improvements and further developments of the exhaust aftertreatment system specified in the independent claim.

[0016] In a preferred embodiment of the invention, the filter element is designed in the form of a filter disc. In this context, a filter disc is understood to be a disc-shaped filter which, in the direction of exhaust gas flow through the filter, has a maximum dimension of 15 mm, preferably a maximum of 10 mm. A filter disc allows, firstly, a filter element with a small installation space requirement to be arranged at the inlet, and secondly, the increase in flow resistance can be limited by the thin material of the filter disc. Furthermore, the funnel allows the inlet cross-section to be designed so that, despite the filter disc, the exhaust gas back pressure in the exhaust duct is only slightly increased.

[0017] In a further preferred embodiment of the invention, the second funnel has a support grid at its inlet, which supports the filter element, in particular the filter disc. The filter element, especially the filter disc, can be held and supported in position at the inlet of the second funnel by means of a support grid, particularly a metallic support grid. This eliminates the risk of the filter element slipping, and in particular the risk of a detached filter disc entering the low-pressure exhaust gas recirculation system.

[0018] According to the invention, the second funnel has an oval inlet geometry. An oval cross-section allows the inlet area to be increased compared to a round geometry, thus enabling more exhaust gas to flow into the exhaust gas recirculation channel of the low-pressure exhaust gas recirculation system. Furthermore, the oval geometry prevents the filter element from twisting.

[0019] In an embodiment not part of the invention, the second funnel has a round or polygonal inlet geometry, in particular a triangular, square, pentagonal, hexagonal, or octagonal one. A polygonal inlet geometry also prevents the filter element from twisting. Furthermore, the polygonal inlet geometry allows for a larger inlet area compared to a round inlet area. A round inlet geometry enables a particularly simple and cost-effective version of the second funnel.

[0020] Preferably, the filter element is shaped to match the geometry of the inlet of the second funnel. By adapting the filter element to the inlet geometry, it is possible to prevent particles or contaminants from bypassing the filter element and entering the second funnel. Preferably, the filter element is stretched over the inlet of the second funnel or fixed by it at the edge to prevent it from coming loose.

[0021] In a preferred embodiment of the invention, the filter element is provided to have an inlet area of ​​3000 mm². 2 up to 5000 mm 2 Features an entry area of ​​at least 3000 mm². 2Sufficient exhaust gas can be recirculated via low-pressure exhaust gas recirculation into the combustion chambers of the internal combustion engine to reduce nitrogen oxide emissions. This requires an inlet area of ​​at least 3000 mm². 2 This ensures that the flow resistance remains low when entering the second funnel. However, the inlet area should be 5000 mm². 2 Do not exceed this limit, otherwise the second funnel will become too large and less exhaust gas will be directed through the third funnel via the main channel towards the tailpipe.

[0022] In a preferred embodiment of the invention, the oval inlet geometry has a length of 60 mm to 200 mm and a width of 30 mm to 100 mm. A length of 100 mm to 120 mm and a width of 60 mm to 75 mm are particularly preferred. A length of 60 mm to 200 mm and a width of 30 mm to 100 mm provides a corresponding inlet area of ​​3000 mm². 2up to 5000 mm 2 This can be achieved. The length-to-width ratio is preferably in the range of 1.5 to 2 in order to achieve the best possible ratio of inlet area to circumference in an oval funnel and to keep flow resistance low.

[0023] According to a preferred embodiment of the invention, the inlet of the second funnel is located at a distance D from the filter body of the particulate filter of 10 mm to 200 mm. A distance of 20 mm to 30 mm from the end of the particulate filter is particularly preferred. The filter element is spaced from the filter body of the particulate filter to facilitate the inflow of exhaust gas that has been cleaned by the filter body. A distance of 10 mm to 200 mm, and especially 20 mm to 30 mm, represents a good compromise between space utilization and increasing the exhaust back pressure through the filter element. Additionally, the filter element can be regenerated during the regeneration of the particulate filter by removing accumulated soot (through soot slippage of the particulate filter). This position ensures a relatively uniform flow, which guarantees uniform combustion of the soot across the entire cross-section.

[0024] In a further preferred embodiment of the invention, the inlet of the second funnel has an inclination angle of 0° to 90° relative to the central axis of the particulate filter. An inclination angle of 20° to 30° between the inlet of the second funnel and the central axis of the particulate filter is particularly preferred. To facilitate flow into the second and third funnels, it is advantageous if the second funnel, in particular, is slightly inclined relative to the central axis of the particulate filter. The deflection should be small to minimize flow resistance. An inclination angle of 20° to 30° represents a good compromise in this regard. Alternatively, inclination angles between 0° and 90° are also possible if space constraints dictate otherwise. Additionally, the filter element can be regenerated during the regeneration of the particulate filter by removing accumulated soot (through soot slippage of the particulate filter).The position ensures a relatively uniform airflow, which guarantees a uniform combustion of the soot across the entire cross-section.

[0025] According to the invention, an internal combustion engine with an inlet and an outlet is proposed, wherein the inlet is connected to an intake tract of the internal combustion engine, wherein the outlet is connected to an exhaust system of the internal combustion engine, wherein the exhaust system has an exhaust channel in which, in the direction of flow of an exhaust gas through the exhaust channel, a turbine of an exhaust gas turbocharger and, downstream of the turbine, a particulate filter are arranged, wherein the particulate filter has a filter body and wherein the particulate filter has a housing which tapers conically downstream of the filter body in the form of an outlet funnel, characterized in that the outlet funnel branches into a second funnel and a third funnel, wherein the second funnel is connected to a low-pressure exhaust gas recirculation system and the third funnel is connected to a main channel of the exhaust system, wherein the second funnel carries a filter element at its inlet.and wherein the second funnel has an oval inlet geometry at its inlet. The combustion engine according to the invention, with its particulate filter and low-pressure exhaust gas recirculation, makes it possible to improve the raw emissions of the combustion engine. Compared to solutions known from the prior art, the short and aerodynamically optimized low-pressure exhaust gas recirculation reduces the exhaust backpressure in the exhaust system, thereby reducing the fuel consumption of the combustion engine. In this context, low-pressure exhaust gas recirculation refers to exhaust gas recirculation that extracts exhaust gas from the exhaust manifold downstream of a turbine of an exhaust gas turbocharger and feeds this exhaust gas to the intake manifold of the combustion engine upstream of a compressor driven by the turbine of the exhaust gas turbocharger. The exhaust aftertreatment system of the combustion engine is thus designed to be compact.This allows the installation space requirement to be kept low and the combustion engine to be installed even in relatively small engine compartments. In this context, a particulate filter arranged close to the engine is understood to mean an arrangement with an exhaust gas flow length of a maximum of 60 cm, preferably a maximum of 40 cm, starting from an exhaust outlet of the combustion engine.

[0026] Furthermore, according to the invention, a particulate filter for the exhaust aftertreatment of an internal combustion engine is proposed, comprising a housing in which a filter body of the particulate filter is arranged, wherein the housing has an inlet opening and two outlet openings, wherein the housing is configured as a first funnel in a first section downstream of the filter body, and branches downstream of the first funnel into a second funnel and a third funnel, wherein the first outlet opening is formed on the second funnel and the second outlet opening on the third funnel, and wherein the second funnel has a support element at its inlet which carries a filter disc. It is provided that the second funnel has an oval inlet geometry.A particulate filter according to the invention can reduce the exhaust back pressure and thus reduce the fuel consumption and / or raw emissions of the combustion engine. Furthermore, more exhaust gas can be introduced into the second funnel, enabling higher exhaust gas recirculation rates via the low-pressure exhaust gas recirculation system.

[0027] In a preferred embodiment of the particle filter, the filter disc is made of a woven fabric, a nonwoven fabric, or another filter material, or a combination of these materials. Using a woven fabric, a nonwoven fabric, or another filter material for the filter disc allows for a simple and cost-effective design. Alternatively, a combination of these filter materials can be used in the filter disc.

[0028] Unless otherwise stated in individual cases, the various embodiments of the invention mentioned in this application can be advantageously combined with one another.

[0029] The invention is explained below using exemplary embodiments with reference to the accompanying drawings. These show: Fig. 1 An embodiment of an internal combustion engine with an exhaust aftertreatment system according to the invention in a schematic representation; Fig. 2 an embodiment of an internal combustion engine according to the invention with an exhaust aftertreatment system according to the invention in a 3D representation; Fig. 3 a particulate filter of an exhaust aftertreatment system according to the invention; Fig. 4 a section along a sectioning plane A - A through a funnel of the particle filter according to the invention; and Fig. 5 another cross-sectional view through a particle filter according to the invention of an exhaust aftertreatment system according to the invention.

[0030] Fig. Figure 1 shows an embodiment of an internal combustion engine 10 according to the invention with an exhaust aftertreatment system according to the invention. The internal combustion engine 10 has an engine block 12 in which at least one combustion chamber 72, preferably as shown in Figure 1, is located. Fig. Figure 1 shows four combustion chambers 72. The internal combustion engine 10 has an inlet 16, which is connected to an intake tract 56 of the internal combustion engine 10. The intake tract 56 includes a fresh gas line 74 in which an air filter 76 and, downstream of the air filter 76, a compressor 78 of an exhaust gas turbocharger 26 are arranged. Downstream of the compressor 78 and upstream of the combustion chambers 72, a charge air cooler 80 is arranged to cool the fresh air compressed by the compressor 78 and thus further improve the filling of the combustion chambers 72. The internal combustion engine 10 also has an outlet 14 to which an exhaust manifold 22 is connected, which is connected to an exhaust system 20 of the internal combustion engine 10. The exhaust system 20 has a first catalyst 30 located close to the engine, in particular an oxidation catalyst, and a particulate filter 32 also located close to the engine downstream of the first catalyst 30.In this context, an arrangement close to the engine is understood to be an arrangement with an exhaust gas flow length of a maximum of 60 cm, preferably a maximum of 40 cm, starting from the outlet 14 of the internal combustion engine 10. The particulate filter 32 has a housing 86 in which a filter element 58 of the particulate filter 32 is arranged. A branch 34 is formed on the particulate filter 32 downstream of the filter element 58 in the direction of exhaust gas flow through the particulate filter 32. At this branch, an exhaust gas channel 24 of the exhaust system 20 splits into a low-pressure exhaust gas recirculation 40 and a main channel 50, which connects the particulate filter 32 to a tailpipe 36 of the exhaust system 20. The low-pressure exhaust gas recirculation 40 has a low-pressure exhaust gas recirculation cooler 46, which is arranged on a side of the internal combustion engine 10 offset by 90° to the outlet side 14 of the internal combustion engine 10, in particular on an end face 18 of the engine block 12.In the exhaust system 20, a turbine 28 of the exhaust gas turbocharger 26 is arranged downstream of the outlet 14 of the combustion engine 10 and upstream of the first catalyst 30, which drives the compressor 78 in the intake tract 56.

[0031] The low-pressure exhaust gas recirculation system 40 has an exhaust gas recirculation channel 42, which connects the exhaust gas channel 24 at the branch 34 downstream of the particulate filter 32 with an inlet 54 into the intake tract 56 downstream of the air filter 76 and upstream of the compressor 78. Immediately following the branch 34, a decoupling element 44 can be arranged in the exhaust gas recirculation channel 42 to decouple the vibrations transmitted to the particulate filter 32 from the exhaust gas recirculation channel 42 caused by the vibrations of the combustion engine 10. The particulate filter 32 has a first funnel 64 downstream of the filter body 58, which branches in the direction of flow into a second funnel 66 and a third funnel 68. The first funnel 64 reduces a flow cross-section Q of the exhaust duct 24 from a first cross-section Q1, which corresponds to the cross-section of the filter body 58, to a second cross-section Q2.The second funnel 66 is connected to the exhaust gas recirculation channel 42 via the decoupling element 44. The second funnel 66 also carries a filter element 70 to prevent soot particles from entering the low-pressure exhaust gas recirculation system 40. The third funnel 68 is connected to the main channel 50 of the exhaust system 20.

[0032] The exhaust gas recirculation channel 42 preferably has a substantially constant cross-section with an inner diameter Di of approximately 40 mm. The length L of the exhaust gas recirculation channel 42 from the branch 34 to the low-pressure exhaust gas recirculation cooler 46 is preferably approximately 530 mm, wherein the exhaust gas recirculation channel 42 has a bend 38 with a bend angle α of approximately 280° in this section. The low-pressure exhaust gas recirculation cooler 46 has a housing 62 which is fastened to an end face 18 of the engine block 12 by means of fastening means 48, in particular by means of bolts 52 or screws 60.

[0033] In an alternative embodiment of the invention, the decoupling element 44 can also be omitted. Furthermore, exhaust gas recirculation channels 42 with a running length of 300 mm to 900 mm, in particular of 450 mm to 650 mm, are conceivable in order to enable efficient and flow-optimized exhaust gas recirculation in a compact design.

[0034] Due to increasingly stringent emissions legislation, particularly regarding nitrogen oxide emissions, it is necessary to combine in-engine measures with exhaust aftertreatment measures. One way to improve the raw emissions of the combustion engine 10 is to mix exhaust gas with the fresh air to reduce the formation of nitrogen oxide emissions. It is advantageous if the recirculated exhaust gas is as cool as possible. For this reason, a low-pressure exhaust gas recirculation cooler 46 is arranged in the low-pressure exhaust gas recirculation system 40. The effectiveness of this cooler 46 is significantly influenced by the heat radiation from the combustion engine 10.The solution according to the invention spatially separates the exhaust gas recirculation cooler 46 from the hot exhaust side 14, in particular from the exhaust manifold 22, thereby improving the effectiveness of the low-pressure exhaust gas recirculation cooler 46 or reducing the amount of coolant that needs to circulate for the same cooling capacity. This improves the overall efficiency of the internal combustion engine 10. Furthermore, the flow resistance in the low-pressure exhaust gas recirculation system 40 can be kept low due to the comparatively large inner diameter Di and a correspondingly large radius of the bend 38, while maintaining a comparatively short length L of the exhaust gas recirculation channel 42. The decoupling element 44 decouples the vibrations and movements of the particulate filter 32 from the low-pressure exhaust gas recirculation system 40, thereby damping the dynamic and thermomechanical movements and reducing the stresses on all components 42, 46, 48 involved in the low-pressure exhaust gas recirculation system 40.

[0035] In Fig. Figure 2 shows the combustion engine 10 according to the invention with the exhaust aftertreatment system according to the invention in a three-dimensional representation. The exhaust aftertreatment system according to the invention enables minimal exhaust backpressure with a compact and space-saving design. The low-pressure exhaust gas recirculation cooler 46 is not directly exposed to the hot exhaust gas on the outlet side 14 and is therefore heated less than comparable exhaust gas recirculation coolers 46. This also allows the length L of the exhaust gas recirculation channel 42 to be shorter, since the exhaust gas requires less cooling along this path.

[0036] Fig. Figure 3 shows a particulate filter 32 of an exhaust aftertreatment system according to the invention. The particulate filter 32 comprises a filter body 58, which is arranged in a housing 86. The housing 86 has an inlet opening 90 and two outlet openings 92, 94. Downstream of the filter body 58, the housing 86 of the particulate filter 32 is designed as an outlet funnel 64, which branches into a second funnel 66 and a third funnel 68. The third funnel 68 preferably has a larger inlet cross-section than the second funnel 66. The second funnel 66 is connected via the first outlet opening 92 to the exhaust gas recirculation channel 42 of a low-pressure exhaust gas recirculation system 40. The third funnel 68 is connected via the second outlet opening 94 to a main channel 50 of the exhaust system 20. The second outlet opening 94 has a larger opening cross-section than the first outlet opening 92.The second funnel 66 has an oval inlet geometry, which tapers to a circular outlet geometry at the first outlet opening 92 to allow the connection of a cylindrical exhaust gas recirculation channel 42. The housing 86 of the particulate filter 32 is made of a metallic material, in particular steel, to withstand the thermal stresses occurring in the exhaust gas channel. A support grid 84 is formed at an inlet 88 of the second funnel 66, which carries a preferably disc-shaped filter element 70. The filter element has a cross-section of preferably about 4000 mm². 2 . In addition, the second funnel 66 has a flow cross-section A of at least 4000 mm² at its inlet side 82. 2to facilitate an inflow into the exhaust gas recirculation channel 42 of the low-pressure exhaust gas recirculation system 40. This allows the exhaust back pressure in the exhaust system 20 to be reduced, thereby lowering the fuel consumption of the internal combustion engine 10 or increasing its power output, and enabling a larger volume flow of exhaust gas to be recirculated in order to reduce the raw emissions, in particular the nitrogen oxide emissions, of the internal combustion engine 10.

[0037] In Fig. Figure 4 shows a section through the particle filter 32 along a section plane A - A, in which the filter element 70 is arranged. The second funnel 66 has an oval inlet geometry. A metallic support grid 84 is formed at a transition between the outlet funnel 64 and the second funnel 66, which supports the filter element 70. This allows the use of a very flat filter element 70, in particular a filter disc 82, since the support grid 84 prevents deformation of the filter element 70. The oval cross-section allows for a comparatively large inlet area of ​​approximately 4000 mm². 2This is achieved by reducing the flow resistance for the inflow of exhaust gas into the low-pressure exhaust gas recirculation system 40, thus allowing a larger volume flow of exhaust gas to be recirculated via the low-pressure exhaust gas recirculation system 40. The oval has a length of approximately 60 mm to 200 mm along its longitudinal side and a width of 30 mm to 100 mm along its narrow side. A length L1 of 100 mm to 120 mm and a width B of 60 mm to 75 mm are particularly preferred. The support grid 84, and thus the filter element 72, is arranged at an inclination angle β of 0° to 90°, preferably 20° to 30°, and particularly preferably 25°, relative to a central axis 96 of the particulate filter 32. The filter element 70 is spaced at a distance D of 10 mm to 200 mm from one end of the filter body 58 of the particle filter 32. Preferably, the distance is 20 mm to 30 mm.

[0038] Another section through such a particle filter 32 according to the invention is shown in Fig. Figure 5 shows. An oval inlet geometry is preferred, since this allows a comparatively large flow cross-section A at the inlet 88 of the second funnel 66 and reduces the flow resistance compared to other inlet geometry shapes. Reference symbol list 10 Internal combustion engine 12 Engine block 14 Outlet / Outlet side 16 Entrance / Entrance side 18 Front 20 Exhaust system 22 Exhaust manifolds 24 Exhaust duct 26 exhaust gas turbochargers 28 Turbine 30 first catalyst / oxidation catalyst 32 particle filters 34 branching 36 Tailpipe 38 bend 40 Low-pressure exhaust gas recirculation 42 Exhaust gas recirculation channel 44 Decoupling element 46 Low-pressure exhaust gas recirculation coolers 48 Fasteners 50 Main Channel 52 bolts 54 Junction 56 Intake tract 58 filter bodies 60 screws 62 cases 64 first funnel / outlet funnel 66 second funnel 68 third funnel 70 filter elements 72 Combustion chamber 74 Fresh gas line 76 air filters 78 compressors 80 Intercoolers 82 filter discs 84 support grids 86 cases 88 admission 90 Entrance opening 92 first outlet opening 94 second outlet opening 96 Center axis α bending angle β Inclination angle A Flow cross-section at the inlet of the second funnel B Width of the filter body D distance D iInner diameter of the exhaust gas recirculation channel L Length of the exhaust gas recirculation channel L1 Length of the filter body Q Cross-section of the exhaust duct Q1 Cross-section of the filter body Q2 Cross-section at the end of the outlet funnel

Claims

[1] Exhaust aftertreatment system for an internal combustion engine (10), comprising an exhaust system (20) which is connected to an outlet (14) of the internal combustion engine (10), wherein the exhaust system has an exhaust channel (24) in which, in the direction of flow of an exhaust gas through the exhaust channel (24), a turbine (28) of an exhaust gas turbocharger (26) and downstream of the turbine (28) a particulate filter (32) are arranged, wherein the particulate filter (32) has a filter body (58) and wherein the particulate filter (32) has a housing (86) which tapers conically downstream of the filter body (58) in the form of an outlet funnel (64), characterized by, that the outlet funnel (64) branches into a second funnel (66) and a third funnel (68), wherein the second funnel (66) is connected to a low-pressure exhaust gas recirculation (40) and the third funnel (68) is connected to a main channel (50) of the exhaust system (20), wherein the second funnel (66) has a filter element (70) at its inlet (88), and wherein the second funnel (66) has an oval inlet geometry at its inlet (88). [2] Exhaust aftertreatment system according to claim 1, characterized by , that the filter element (70) is designed in the form of a filter disc (82). [3] Exhaust aftertreatment system according to claim 1 or 2, characterized by , that the second funnel (66) has a support grid (84) at its inlet (88) which carries the filter element (70). [4] Exhaust aftertreatment system according to any one of claims 1 to 3, characterized by, that the filter element (70) is adapted in its shape to the geometry of the inlet (88) of the second funnel (66). [5] Exhaust aftertreatment system according to any one of claims 1 to 4, characterized by , that the filter element (70) has an inlet area (A) of 3000 mm² 2 up to 5000 mm 2 exhibits. [6] Exhaust aftertreatment system according to any one of claims 1 to 5, characterized by , that the oval inlet geometry has a length (L1) of 60 mm to 200 mm and a width (B) of 30 mm to 100 mm. [7] Exhaust aftertreatment system according to any one of claims 1 to 6, characterized by , that the inlet (88) of the second funnel (66) has a distance (D) from the filter body (58) of the particle filter (32) of 10 mm to 200 mm. [8] Exhaust aftertreatment system according to any one of claims 1 to 7, characterized by, that the inlet (88) of the second funnel (66) has an inclination angle (β) of 0° to 90° relative to a central axis (96) of the particle filter (32). [9] Internal combustion engine (10) with an inlet (16) and an outlet (14), wherein the inlet (16) is connected to an intake tract (56) of the internal combustion engine (10), and wherein the outlet (14) is connected to an exhaust system (20) of the internal combustion engine (10), wherein the exhaust system (20) has an exhaust channel (24) in which, in the direction of flow of an exhaust gas through the exhaust channel (24), a turbine (28) of an exhaust gas turbocharger (26) and, downstream of the turbine (28), a particulate filter (32) are arranged, wherein the particulate filter (32) has a filter body (58) and wherein the particulate filter (32) has a housing (86) which tapers conically downstream of the filter body (58) in the form of an outlet funnel (64), characterized by, that the outlet funnel (64) branches into a second funnel (66) and a third funnel (68), wherein the second funnel (66) is connected to a low-pressure exhaust gas recirculation (40) and the third funnel (68) is connected to a main channel (50) of the exhaust system (20), wherein the second funnel (66) has a filter element (70) at its inlet (88), and wherein the second funnel (66) has an oval inlet geometry at its inlet (88). [10] Particulate filter (32) for exhaust aftertreatment of an internal combustion engine (10), comprising a housing (86) in which a filter body (58) of the particulate filter (32) is arranged, wherein the housing (86) has an inlet opening (92) and two outlet openings (94, 96), wherein the housing (86) is configured in a first section downstream of the filter body (58) as a first funnel (64), and branches downstream of the first funnel (64) into a second funnel (66) and a third funnel (68), wherein the first outlet opening (94) is configured on the second funnel (66) and the second outlet opening (96) is configured on the third funnel (68), wherein the second funnel (66) has a support element (84) at its inlet (88) which carries a filter disc (82), and wherein the second funnel (66) at its inlet (88) has an oval inlet geometry. [11] Particle filter (32) according to claim 10, characterized by, that the filter disc (82) consists of a fabric, a fleece or other filter material or a combination of these materials.

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