Hybrid structure assembly for exhaust equipment of internal combustion engine

Abstract

The invention relates to a mixing structure assembly for an exhaust apparatus of an internal combustion engine for mixing exhaust gases discharged from the internal combustion engine with a reaction agent, having a mixing section (12) which extends in the direction of a longitudinal axis (L) of the mixing section, comprising an upstream mixing section inflow area (24) for receiving exhaust gases and / or reaction agent in the mixing section (12), comprising a core flow channel (18) which can be flowed through by a first exhaust gas partial flow (T1) and a bypass flow channel (20) which can be flowed through by a second exhaust gas partial flow (T2), characterized in that at least one flow obstruction element (38, 38') which reduces the flow cross section of the bypass flow channel (20) is provided in the bypass flow channel (20).

Description

Technical Field

[0001] The present invention relates to a mixing structure assembly for an exhaust system of an internal combustion engine, which is used to mix exhaust gas discharged from the internal combustion engine with a reactant. Background Technology

[0002] A mixing structure assembly for an exhaust system of an internal combustion engine is known from DE 10 2020 109 022 A1, wherein a core flow passage is substantially concentrically surrounded by a bypass flow passage providing a peripheral flow passage. A reactant output assembly has an injector and a radially widening mixer following the injector. A portion of the first portion of the exhaust flow introduced into the core flow passage enters the internal volume of the mixer and flows into the core flow passage together with the reactant also injected into that internal volume, so that substantially no reactant reaches the second portion of the exhaust flow introduced into the peripheral flow passage. The core flow passage and the peripheral flow passage have substantially constant flow cross-sections along the longitudinal axis of the mixing section, i.e., along the direction of the main flow of exhaust gas in the respective flow passages. Summary of the Invention

[0003] The objective of this invention is to provide a hybrid structural assembly for exhaust systems of internal combustion engines, which can be easily adapted to different installation environments with a structurally simple design.

[0004] According to the present invention, this task is solved by a mixing structure assembly for an exhaust system of an internal combustion engine, the mixing structure assembly being used to mix exhaust gas discharged from the internal combustion engine with a reactant. The mixing structure assembly includes a mixing section extending along the longitudinal axis of a mixing section, the mixing section including an upstream mixing section inflow region for receiving exhaust gas and / or reactant within the mixing section, the mixing section including a core flow channel through which a first exhaust gas portion flows and a bypass flow channel through which a second exhaust gas portion flows. At least one flow blocking element is provided in the bypass flow channel to reduce the flow cross-section of the bypass flow channel.

[0005] By incorporating at least one flow-blocking element in the bypass flow channel, it is possible to influence the flow resistance and thereby also the mass flow of exhaust gas flowing through the bypass flow channel, without altering the structure of the components defining the different flow channels. Thus, the distribution of the entire exhaust flow to the two exhaust sections can be influenced simply by selecting the shape or size of such a flow-blocking element, adapting it to the exhaust system or internal combustion engine using such a mixing structure assembly. Therefore, the back pressure of the entire exhaust system can be optimally adapted to the operating environment, and optimized mixing of exhaust gas and reactants can be achieved in the mixing section, or in the exhaust treatment unit (e.g., upstream of the SCR catalytic converter).

[0006] In order to achieve efficient thermal shielding of the peripheral flow channel by means of the bypass flow channel, it is proposed that the bypass flow channel has a peripheral flow channel that surrounds the core flow channel in an annular shape, and at least one flow blocking element includes a flow blocking ring disposed in the peripheral flow channel.

[0007] In the peripheral flow channel, a substantially uniform blockage along its entire circumference can be achieved, for example, by having the flow blockage ring completely surround the longitudinal axis of the mixing section and thus form, for example, a closed ring.

[0008] The mixing section may include: an outer mixing section housing defining a peripheral flow channel radially outward; and an inner mixing section housing defining a core flow channel radially outward and separating the core flow channel from the peripheral flow channel. Here, at least one flow blocking element may be fixed to the inner side of the outer mixing section housing facing the peripheral flow channel, thereby forming a flow-through region between the flow blocking element and the outer side of the inner mixing section housing facing the peripheral flow channel, the flow-through region having a reduced flow cross-section with respect to the flow cross-section of the peripheral flow channel upstream of the at least one flow blocking element and with respect to the flow cross-section of the peripheral flow channel downstream of the at least one flow blocking element. Alternatively or additionally, at least one flow blocking element may be fixed to the outer side of the inner mixing section housing facing the peripheral flow channel, thereby forming a flow-through region between the flow blocking element and the inner side of the outer mixing section housing facing the peripheral flow channel, the flow-through region having a reduced flow cross-section with respect to the flow cross-section of the peripheral flow channel upstream of the at least one flow blocking element and with respect to the flow cross-section of the peripheral flow channel downstream of the at least one flow blocking element.

[0009] To stably connect such a flow blocking ring, the flow blocking ring may have an annular body with an L-shaped cross-sectional profile, wherein a first L-leg of the annular body is fixed to the inner side of the outer mixing section housing and a second L-leg extending from the first L-leg extends radially into the peripheral flow channel and defines a flow passage area with the inner mixing section housing; or, the first L-leg of the annular body is fixed to the outer side of the inner mixing section housing and a second L-leg extending from the first L-leg extends radially into the peripheral flow channel and defines a flow passage area with the outer mixing section housing.

[0010] The flow blocking ring is secured to the mixing section housing against mechanical, thermal, and chemical influences, for example, by force-locking and / or material-locking the annular body to the outer or inner mixing section housing with its first L-leg, preferably by welding.

[0011] To further influence the flow resistance, at least two flow blocking elements can be successively and alternately fixed to the inner and outer mixing section shells along the longitudinal axis of the mixing section.

[0012] To achieve a corrugated flow path, at least one flow blocking element fixed to the inner mixing section housing and at least one flow blocking element fixed to the outer mixing section housing can overlap each other radially.

[0013] In order to achieve the most uniform exhaust flow possible in the bypass flow channel, it is proposed that at least one flow blocking element be set in the region of the mixing section inflow area.

[0014] A reactant output component can be provided to output the reactant into the mixing section.

[0015] In order to improve the mixing of exhaust gas and reactant, the reactant output assembly may include a mixer, which may be configured to be radially widened, for example, along the direction of the main reactant output direction.

[0016] To avoid reactant deposits in the bypass flow channel region, it is proposed that the reactant output assembly be configured to output reactant essentially only into the first exhaust portion of the flow.

[0017] The present invention also relates to an exhaust device having a mixing section constructed in accordance with the principles of the present invention. Attached Figure Description

[0018] The invention will now be described in detail with reference to the accompanying drawings. In the drawings:

[0019] Figure 1 A schematic diagram of a hybrid structural assembly for an exhaust system used in an internal combustion engine is shown.

[0020] Figure 2 Show Figure 1 The internal mixing section of the mixing section housing includes a flow blocking ring disposed on its outer side;

[0021] Figure 3 Show Figure 1 A perspective and partially transparent view of a mixed segment. Detailed Implementation

[0022] exist Figure 1The designation 12 denotes a mixing section, for example, provided in a vehicle as part of an exhaust system for an internal combustion engine, generally designated 10. The mixing section 12 includes, for example, a tubular, substantially cylindrical inner mixing section housing 14 extending along the longitudinal axis L of the mixing section. With respect to the longitudinal axis L, the inner mixing section housing 14 is radially surrounded by, for example, a similarly tubular or cylindrical outer mixing section housing 16. The inner mixing section housing 14 radially delimits the core flow passage 18 of the mixing section 12. In the illustrated design embodiment, a peripheral flow passage 22, substantially concentrically surrounding the core flow passage 18 and providing a bypass flow passage 20, is radially delimited by the inner mixing section housing 14 and radially outward by the outer mixing section housing 16.

[0023] Exhaust flow A from the internal combustion engine flows into the mixing section 12, or core flow passage 18 and peripheral flow passage 22, in the upstream mixing section inlet region 24. A portion of exhaust flow A enters the core flow passage 18 as a first exhaust component flow T1 and flows through the core flow passage 18 substantially along the longitudinal axis L of the mixing section along the inner mixing section housing 14. The remaining portion of exhaust flow A enters the peripheral flow passage 22 as a second exhaust component flow T2 and flows along the peripheral flow passage 22 along the inner mixing section housing 14, or outer mixing section housing 16. In the downstream mixing section outlet region 26, these two exhaust component flows T1 and T2 may meet again and flow toward an exhaust treatment unit (e.g., an SCR catalytic converter or the like) located downstream of the mixing section 12.

[0024] The mixing section 12 also includes a reactant output assembly, generally indicated by 28. The reactant output assembly 28 has a syringe 30 that delivers a reactant (e.g., urea / aqueous solution) in liquid form to it via a jet cone 32 along a main reactant output direction H oriented substantially in the direction of the longitudinal axis L of the mixing section. A mixer 34 is connected downstream of the syringe 30. This mixer may be constructed, for example, with a wall that is frustoconical and radially widens along the main reactant output direction H, thus surrounding and defining a mixing volume into which the reactant output by the syringe 30 via the jet cone 32 is introduced, and a portion of a first exhaust stream T1 also enters the mixing volume through an opening formed in the wall of the mixer 34. This portion of the first exhaust stream T1 flows into the core flow channel 18 along with the reactant output by the syringe 30. The remainder of the first exhaust stream T1 flows along the outside of the mixer 34 through a gap-like intermediate space 36 formed between the mixer 34 and the inner mixing section housing 14 into the core flow channel 18.

[0025] As can be seen, in this arrangement of the reactant output assembly 28, the reactant discharged by the syringe 30 is introduced into the core flow channel 18 almost entirely, or only entirely, along with the first exhaust portion T1. This prevents the reactant from reaching the peripheral flow channel 22 and forming deposits there. It should be considered that an important function of the peripheral flow channel 22 is to provide thermal shielding to the environment from the core flow channel 18, and therefore, in particular, the outer mixing section housing 16 can have a relatively low temperature, which may promote the condensation of the reactant and thus generate deposits.

[0026] It should be noted that, for example, the reactant output assembly 28 can also be configured such that the mixer 34 is positioned within the core flow channel 18 and / or there is no gap-like intermediate space between the downstream end of the mixer 34 and the inner mixing section housing 14, so that all the first exhaust portion flow T1 passes through the mixer 34 and is introduced into the core flow channel 18.

[0027] An external flow channel 22 is provided with Figure 1 The flow blocking element 38 is shown in the schematic diagram. The flow blocking element 38 is positioned such that it abuts against or is held against the outer side 40 of the inner mixing section housing 14, and a flow-through region 44 is formed between the flow blocking element 38 and the inner side 42 of the outer mixing section housing 16. In the flow-through region 44, the flow cross-section of the peripheral flow channel 22 decreases with respect to its flow cross-section upstream of the flow blocking element 38 and with respect to its flow cross-section downstream of the flow blocking element 38.

[0028] exist Figure 2 The flow blocking element 38 disposed on the outer side 40 of the inner mixing section housing 14 can be seen more clearly. The flow blocking element 38 is constituted as a flow blocking ring 46. The flow blocking ring 46 substantially completely or uninterruptedly surrounds the longitudinal axis L of the mixing section, or the inner mixing section housing 14, in the circumferential direction and has an annular body 48 having a substantially L-shaped cross-section. The first L-leg 50 of the annular body 48 extends substantially along the longitudinal axis L of the mixing section and abuts against the outer side 40 of the inner mixing section housing 14. The second L-leg 52 of the annular body 48 extends radially outward from the first L-leg 50 and is thus defined together with the outer mixing section housing 16. Figure 1 The flow-through region 44 can be seen in the image. Based on the annular structure of the flow blocking element 38, the flow-through region 44 also has an annular structure surrounding the longitudinal axis L of the mixing section.

[0029] By placing the flow blocking element 38 in the peripheral flow channel 22 and the resulting contraction in the flow cross-section in the local region, the flow resistance of the peripheral flow channel 22 is increased. This increase in flow resistance depends essentially on the radial extension of the second L-leg 52 and the flow cross-sectional area thus defined in the flow-through region 44. Therefore, it is feasible to adjust the flow resistance in the peripheral flow channel 22 and thereby adjust the proportion of the entire exhaust flow A flowing through the peripheral flow channel 22, i.e., the second exhaust portion T2, and thus also adjust the proportion of the corresponding mass flow through the core flow channel 18 and the peripheral flow channel 22, by selecting the size or shape of the flow blocking element 38. Thus, the distribution of exhaust portions T1 and T2 can be significantly affected simply by selecting the shape or size of the flow blocking element 38, and the mixing section 12 can be adapted to different operating environments (i.e., for example, in conjunction with the use of internal combustion engines of different configurations or sizes), without requiring structural changes to the components defining the flow channel, i.e., the inner mixing section housing 14 or the outer mixing section housing 16. This enables the provision of a mixing section 12 for mass use, which has a basic structure, particularly an inner mixing section housing 14 and an outer mixing section housing 16, and is adapted to different usage environments by inserting flow blocking elements 38 of different configurations.

[0030] Although the flow blocking element 38 is on the outer side 40 of the internal mixing zone housing 14 Figure 2 and 3 The positioning, as can be seen, is particularly advantageous because it avoids heat loss towards the external mixing section housing 16 introduced through the flow blocking element 38. Figure 1 As shown by the alternative positioning of the flow blocking element 38' (shown in dashed lines), this flow blocking element can also, in principle, be disposed on the outer mixing section housing 16, thereby forming a flow passage region 44' between the flow blocking element 38' and the outer side of the inner mixing section housing 14. Here, the first L-leg of the flow blocking element 38, provided as a flow blocking ring, can be positioned abuttingly on the inner side 42 of the outer mixing section housing 16, for example, as shown in... Figure 2 In the design shown, the first L-leg extends downstream from the second L-leg.

[0031] In principle, multiple flow blocking elements can be successively arranged along the flow direction in the outer flow channel 22. For example, one flow blocking element 38 can be alternately arranged on the inner mixing section housing 14 and one flow blocking element 38' can be arranged on the outer mixing section housing 16, thereby predetermining the flow direction of the second exhaust section T2. Figure 2The upper part of the flow path is corrugated by the flow arrow, which further increases the flow resistance. For this purpose, the flow blocking elements 38, 38' arranged successively and alternately on the inner mixing section housing 14 and the outer mixing section housing 16 along the longitudinal axis L of the mixing section can be sized radially, that is, in the region of their respective second L legs, such that the flow blocking elements overlap radially.

[0032] For a stable connection, the flow blocking element 38 can be fixedly connected to the respective supporting mixing section housing 14 or 16 by material locking (e.g., by welding). Here, for example, the first L-leg can be fixed to the corresponding mixing section housing 14 or 16 in its downstream end region and / or its upstream end region by, for example, a circumferential weld or by individual weld points. Alternatively or additionally, a stable connection can also be achieved by force locking, i.e., by friction locking, in which the flow blocking element 38, with its annular body 48, is axially pressed against or into the respective supporting mixing section housing 14 or 16.

[0033] Especially Figure 1 and 3 As can be seen, the flow blocking element 38 is positioned near the upstream mixing section inflow region 24. This can be achieved, for example, by ensuring that the longitudinal section of the peripheral flow channel 22 between the upstream inflow region 24 and the flow blocking element 38 is less than half, preferably less than 20% of the total length of the peripheral flow channel 22 along the longitudinal axis L of the mixing section. This substantially avoids flow blockage or dead space in the peripheral flow channel 22, thereby ensuring uniform flow through the peripheral flow channel and, in particular, ensuring reliable thermal shielding of the core flow channel 18 through the second exhaust portion flow T2.

[0034] It should be noted that the flow blocking element 38, provided as a separate component in the peripheral flow channel 22 or the bypass flow channel 20 generally parallel to the core flow channel 18, can also be provided with a different geometry. Thus, the two L-legs 50, 52 are not necessarily required to have... Figure 2 The orientations are substantially orthogonal to each other, as can be seen in the diagram. The angle between the two L-legs can also be, for example, greater than or less than 90°. Furthermore, the radial extension length of the second L-leg 52, which primarily contributes to the contraction of the flow cross-section, can vary circumferentially around the longitudinal axis L of the mixing section, thereby creating a circumferentially varying blocking effect. The flow blocking element 38 can also be provided circumferentially interrupted or by a plurality of components arranged successively in the circumferential direction, for example, staggered from each other along the direction of the longitudinal axis L of the mixing section.

Claims

1. A mixing structure assembly for an exhaust system of an internal combustion engine, the mixing structure assembly being used to mix exhaust gas discharged from an internal combustion engine with a reactant, the mixing structure assembly comprising a mixing section (12) extending along a longitudinal axis (L) of a mixing section, the mixing section comprising an upstream mixing section inflow region (24) for receiving exhaust gas and / or reactant in the mixing section (12), the mixing section having a core flow passage (18) through which a first exhaust gas fraction (T1) can pass and a bypass flow passage (20) through which a second exhaust gas fraction (T2) can pass, wherein at least one flow blocking element (38, 38') is provided in the bypass flow passage (20) for reducing the flow cross-section of the bypass flow passage (20), the bypass flow passage (20) having an annular peripheral flow passage (22) surrounding the core flow passage (18), and at least one flow blocking element (38, 38') comprising a flow blocking ring (46) disposed in the peripheral flow passage (22), the mixing section (12) comprising: An outer mixing section shell (16) radially outwardly confined to the peripheral flow channel (22); and an inner mixing section shell (14) radially outwardly confined to the core flow channel (18) and separating the core flow channel from the peripheral flow channel (22), and At least one flow blocking element (38') is fixed on the inner side (42) of the outer mixing section housing (16) facing the peripheral flow channel (22), thereby forming a flow crossing region (44') between the flow blocking element (38') and the outer side (40) of the inner mixing section housing (14) facing the peripheral flow channel (22), the flow crossing region having a reduced flow cross-section with respect to the flow cross-section of the peripheral flow channel (22) upstream of the at least one flow blocking element (38') and the flow cross-section of the peripheral flow channel (22) downstream of the at least one flow blocking element (38'), characterized in that, At least one flow blocking element (38) is fixed on the outer side (40) of the inner mixing section housing (14) facing the outer peripheral flow channel (22), thereby forming a flow crossing region (44) between the flow blocking element (38) and the inner side (42) of the outer mixing section housing (16) facing the outer peripheral flow channel (22), the flow crossing region having a reduced flow cross-section with respect to the flow cross-section of the outer peripheral flow channel (22) upstream of the at least one flow blocking element (38) and with respect to the flow cross-section of the outer peripheral flow channel (22) downstream of the at least one flow blocking element (38).

2. The hybrid structural assembly according to claim 1, characterized in that, The flow blocking ring (46) completely surrounds the longitudinal axis (L) of the mixing section.

3. The hybrid structural assembly according to claim 1 or 2, characterized in that, The flow blocking ring (46) has an annular body (48) with an L-shaped cross-sectional profile. The first L-leg of the annular body is fixed to the inner side (42) of the outer mixing section shell (16), and the second L-leg extending from the first L-leg extends radially into the outer flow channel (22) and defines a flow passage area (44') with the inner mixing section shell (14), or The first L-leg (50) of the annular body (48) is fixed on the outer side (40) of the inner mixing section housing (14), and the second L-leg (52) extending from the first L-leg (50) extends radially into the outer flow channel (22) and defines the flow area (44) with the outer mixing section housing (16).

4. The hybrid structural assembly according to claim 3, characterized in that, The annular body is secured to the outer mixing section housing (16) or the inner mixing section housing (14) by force locking and / or material locking with its first L-leg (50).

5. The hybrid structural assembly according to claim 4, characterized in that, The annular body is fixed to the outer mixing section shell (16) or the inner mixing section shell (14) by welding with its first L-leg (50).

6. The hybrid structural assembly according to claim 1 or 2, characterized in that, At least two flow blocking elements (38, 38') are successively and alternately fixed on the inner mixing section housing (14) and the outer mixing section housing (16) along the longitudinal axis (L) of the mixing section.

7. The hybrid structural assembly according to claim 6, characterized in that, At least one flow blocking element (38) fixed on the inner mixing section housing (14) and at least one flow blocking element (38') fixed on the outer mixing section housing (16) overlap each other radially.

8. The hybrid structural assembly according to claim 1 or 2, characterized in that, At least one flow blocking element (38, 38') is disposed in the region of the mixing section inflow region (24).

9. The hybrid structural assembly according to claim 1 or 2, characterized in that, A reactant output component (28) is provided for outputting reactants into the mixing section (12).

10. The hybrid structural assembly according to claim 9, characterized in that, The reactant output assembly (28) includes a mixer (34) that is widened in the radial direction.

11. The hybrid structural assembly according to claim 10, characterized in that, The mixer (34) is radially widened along the main output direction (H) of the reactant.

12. The hybrid structural assembly according to claim 9, characterized in that, The reactant output assembly (28) is configured to output the reactant only into the first exhaust stream (T1).

13. An exhaust device having a hybrid structural assembly according to any one of claims 1 to 12.

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