DE102010002245A1 - Exhaust line structure of an internal combustion engine - Google Patents

Abstract

An exhaust pipe arrangement of an internal combustion engine having a sill (14) formed on the periphery of a recessed space (10) disposed upstream in the flow direction of an exhaust gas and a recessed portion (16) formed on an inner surface of a pipe wall. Due to this structure, around a disposition position of an injection port (6a) of a supply valve (6), a space into which no exhaust gas flows can be secured. Therefore, both in the case where an exhaust gas flow rate is low and in the case where an exhaust gas flow rate is high, a urea aqueous solution (12) injected in a relatively small amount can be sufficiently contained in the recessed space (10). in which no exhaust gas flows, be distributed. The aqueous urea solution (12) does not adhere directly to an inner surface of the exhaust pipe (2). Accordingly, after being dispersed in the recessed space (10), the aqueous urea solution (12) is dispersed in the exhaust gas stream and then sent to a downstream catalyst. Therefore, the urea aqueous solution (12) or urea particles resulting therefrom are homogeneously dispersed instead of being mixed with the exhaust gas in an unbalanced state.

Description

BACKGROUND OF THE INVENTION

1. Field of the invention

The The invention relates to an exhaust pipe arrangement of an internal combustion engine, having an exhaust pipe into which an additive from a supply valve is injected.

2. Description of the state of the technique

Various catalysts, such as. For example, a selective NOx reduction catalyst (an SCR catalyst), a NOx occluding and reducing catalyst, a direct NOx reduction catalyst and the like are known as catalysts for reducing the amount of NOx in a diesel engine. For example, in an exhaust gas purification system in which a urea-SCR catalyst is provided, an aqueous urea solution is supplied to an exhaust pipe of a diesel engine to be mixed with the exhaust gas and thus purify the exhaust gas by a reduction reaction of NOx (see, for example, US Pat The published Japanese patent application JP 2007-332797 , the published Japanese patent application JP 2006-77691 and the published Japanese patent application JP 2008-128048 ).

In these published patent applications, the flow of the exhaust gas and the direction of injection of the additive (or a cleaning agent) are taken into account to ensure that the additive is homogeneously mixed with the entire exhaust gas. In the published Japanese patent application JP 2007-332797 That is, a shield plate, which is inclined with respect to a direction of the exhaust gas flow, is disposed upstream of a position where the cleaning agent is input to the exhaust pipe, but the shield plate rises from an inner surface of the exhaust pipe at right angles to a swirling flow to produce the exhaust gas.

In the published Japanese patent application JP 2006-77691 That is, a recess portion on which a supply valve is disposed is formed outside a bent portion of the exhaust pipe, and an additive is injected out of this recess portion toward an opposite inner wall. It is likely that the additive adhered to the inner wall is supplied to the exhaust gas flow through an upstream annular elevation.

In the published Japanese patent application JP 2008-128048 the injection direction of the additive is guided by a specially shaped wall surface so that the additive flows perpendicular to the flow of the exhaust gas. Therefore, the additive is homogeneously mixed with the entire exhaust gas.

Even if the shielding as in the published Japanese patent application JP 2007-332797 described perpendicularly projecting from the inner wall of the exhaust pipe, however, reaches an exhaust gas stream, which has not been sufficiently swirled by the shield, the supply valve, especially if the Abgasdruchflussrate is low at low engine speeds or the like. This may cause the additive injected from the supply valve to flow downstream without being sufficiently mixed with the entire exhaust gas stream.

In order to homogeneously distribute the additive injected from the supply valve into the exhaust gas, the supply valve may be disposed in a concaved-in area (a recessed space) of an inner surface of the exhaust pipe, as disclosed in Published Japanese Patent Application JP 2006-77691 is described. However, in this arrangement, when the exhaust gas flow rate is low, exhaust gas flows directly into the recessed space instead of flowing past an area above the recessed space. The exhaust gas thus flowed into the recessed space causes the additive corresponding to the smaller exhaust gas flow rate to be injected in a smaller amount, adhering directly to a pipe wall of the exhaust pipe. As a result, it is not easy to distribute the injected additive throughout the exhaust flow.

In the published Japanese patent application JP-2008-128048 the additive is injected along a portion of the wall surface. Therefore, especially when the exhaust gas flow rate is low, and particularly when the amount of reducing agent is small, additive adheres to parts of the pipe wall of the exhaust pipe. As a result, it is not easy to distribute the injected additive throughout the exhaust flow.

SUMMARY OF THE INVENTION

As described above, in Published Japanese Patent Application JP 2007-332797 , the published Japanese patent application JP 2006-77691 and the published Japanese patent application JP 2008-128048 takes no action against the case where the exhaust gas exhaust flow rate is low and the additive can not be distributed homogeneously in the exhaust gas flow in a simple manner when the exhaust gas exhaust flow rate is low. The object of the invention is an exhaust pipe arrangement of an internal combustion engine, which it regardless of the Abgasdruch flow rate allows to distribute an additive homogeneously in the exhaust gas.

Therefore according to one aspect of the invention is an exhaust pipe arrangement an internal combustion engine provided, which has an exhaust pipe, into which an additive is injected from a supply valve. These Exhaust pipe arrangement of an internal combustion engine is with a dam or a threshold, which with respect to a flow direction of the exhaust gas upstream of an injection opening disposition position the supply valve from an inner surface of a pipe wall protrudes, and a recess portion, which on an inner surface a pipe wall is provided, which is the inner surface of the pipe wall opposite, at which provided the threshold in the exhaust pipe is equipped.

The so from the inner surface of the pipe wall protruding threshold is with respect to the flow direction of the exhaust gas upstream of the injection opening disposition position provided the supply valve. Therefore, exhaust gas reaches which along the inner surface of the pipe wall has flowed, the threshold right in front of the injection opening arrangement of the Supply valve. The recess portion is on the inner surface the pipe wall provided the inner surface of the pipe wall is opposite, at which the threshold is provided. Therefore is exhaust, regardless of the exhaust gas flow rate of the inner surface of the pipe wall on the side on which the injection opening disposition position of the supply valve is thrown up, and the exhaust flow becomes temporary from the inner surface of the pipe wall on the side on which the injection opening arrangement of the supply valve is located, separated. Thus, downstream the threshold is around the spot a space is formed around the injection port assembly, in which no exhaust gas flows. Accordingly, the additive becomes from the supply valve into this room, in which no exhaust gas flows, injected.

The In this space injected additive is not directly in the Promoted exhaust gas flow. Thus, the additive, after it essentially disseminated throughout this space has, from an interface between this space and one Room in which exhaust gas flows distributed in the exhaust gas flow.

Especially in the event that the exhaust gas flow rate in the internal combustion engine is low, the amount of injected additive is also low. In the event that, however, also the amount of injected Additive is accordingly low, the additive is sufficient distributed in the room, does not flow into the exhaust. Therefore The additive does not adhere immediately to the pipe wall of the exhaust pipe. Therefore, the additive, after it has been distributed, from the interface distributed between the rooms and to the exhaust gas flow promoted. Therefore, the additive becomes even at a low Flow rate homogeneously distributed in the exhaust gas.

As has been described above, the additive may be independent of the exhaust gas flow rate are distributed homogeneously in the exhaust gas. In the exhaust pipe arrangement of the internal combustion engine has the threshold preferably one of the flow direction of the exhaust gas opposite front surface, which in relation to the Inner surface of the pipe wall rises diagonally.

There the front surface of the sill the inner surface of the pipe wall rises diagonally, can open this way prevents the generation of a swirling flow to guide the exhaust stream evenly. Thus, the injection port arrangement located downstream of the threshold may a sufficient space is created around, in which no Exhaust gas flows in. As described above, the additive regardless of the exhaust gas flow rate distributed homogeneously in the exhaust gas become.

Farther is the threshold in the exhaust pipe arrangement of an internal combustion engine preferably formed in a shape which by pressing the pipe wall itself is obtained from the exhaust pipe to the inside.

If instead of forming the threshold the pipe wall itself is deformed a special element such. B. a shield on the inner surface of the To arrange pipe, can be formed in this way the threshold be arranged without further elements except the pipe wall to have to. Accordingly, both the exhaust pipe arrangement simplified as well as a contribution to weight reduction be made.

Farther In the exhaust pipe arrangement of the internal combustion engine, the recess portion formed in a shape which by bulging a Pipe wall itself is obtained from the exhaust pipe to the outside.

If the recessed portion is formed in a shape which obtained by bulging the pipe wall itself from the exhaust pipe instead of other special elements such as one To arrange shielding plate on the inner surface of the tube wall, In this way, the threshold can be formed without special To arrange elements except the pipe wall. Accordingly, both the exhaust pipe arrangement can be simplified, as well as contributing to weight reduction.

Farther extend in the exhaust pipe arrangement of the internal combustion engine preferably both ends of the threshold to the respective one of the two Side portions of the injection opening disposition position.

There the threshold to both side areas of the injection opening arrangement position extends exhaust gas can be prevented in this way, from both sides of the injection opening disposition position to flow. As a result, can even better prevented be that exhaust gas in the vicinity of the injection opening arrangement position flows.

Farther Preferably, both ends of the threshold extend in the exhaust pipe arrangement of a Internal combustion engine with respect to the flow direction of the exhaust gas downstream to the injection opening disposition position to surround.

There the threshold is extended to the injection opening disposition position This way, exhaust gas as well as a turbulent flow can flow around thereof or the like more reliably prevented be in the vicinity of the injection opening arrangement position to flow.

Farther In the exhaust pipe arrangement of the internal combustion engine, the injection opening disposition position is with respect to the flow direction of the exhaust gas, preferably between two upstream and downstream provided Arranged thresholds, in particular between the threshold and a other threshold, which is provided so that they respect the flow direction of the exhaust gas downstream from the injection port disposition position of an inner surface a pipe wall protrudes.

There the thresholds with respect to a flow direction the exhaust gas both upstream and downstream are provided, can in this way exhaust gas as well as a swirled Flow from it or similar more reliable be prevented from entering the vicinity of the injection opening arrangement position to flow. Furthermore, the injection opening disposition position in the exhaust pipe arrangement of the internal combustion engine, preferably within a bent portion of the exhaust pipe or in the vicinity of the arranged curved portion of the exhaust pipe.

For the case that the injection opening disposition position within the bent portion of the exhaust pipe or in the environment arranged therefrom, the exhaust pipe may be due to limitations arranged or formed in the design of the exhaust pipe be that is likely that exhaust gas to the location of the injection hole arrangement flows.

In However, this case can also be provided by the above-described the threshold and the recessed portion are easily effected that exhaust gas is unlikely to be to the injection port disposition position flows. Accordingly, despite the presence of the additive the above restrictions regardless of the Exhaust gas flow rate can be homogeneously distributed in the exhaust gas.

Farther In the exhaust pipe arrangement of the internal combustion engine, the injection opening disposition position is preferably in a formed on the inner surface of the tube wall to arrange recessed room and the threshold at the edge of the recessed Space to arrange, with respect to the flow direction the exhaust gas is formed upstream.

The Injection opening arrangement position can there in the recessed Room can be arranged where the threshold to the respect the flow direction of the exhaust gas upstream trained edge is arranged. Thus, around the injection opening disposition position around a sufficient space are formed, in which no exhaust flows in, and the homogeneous distribution of the additive in the exhaust gas can be effective regardless of the exhaust gas flow rate be improved.

Farther is the recessed in the exhaust pipe assembly of the internal combustion engine Space preferably formed in a shape, which by bulging the pipe wall itself obtained from the exhaust pipe to the outside becomes.

On in this way, the recess portion is formed in a mold which by bulging the pipe wall itself from the exhaust pipe can be obtained without further special items except to arrange the pipe wall. Accordingly, both the exhaust pipe arrangement simplified as well as contributing to weight reduction become.

Farther extend in the exhaust pipe arrangement of the internal combustion engine preferably both ends of the threshold with respect to the flow direction of the exhaust gas downstream of the edges, respectively of the respective two side areas of the recessed space.

In this way, since both ends of the sill extend to the edges of the side portions of the recessed space, the exhaust gas can be prevented from flowing in from both sides of the recessed space and the process of preventing the exhaust gas from flowing into the surroundings the injection opening disposition position can be assisted.

Farther extend in the exhaust pipe arrangement of the internal combustion engine both ends of the threshold preferably such that they the recessed Surrounding space along its entire circumference annular.

There both ends of the threshold to the edges of the side areas of the recessed space can be expanded in this way the exhaust be more reliably prevented from entering the environment Inject injection opening arrangement position.

Farther is the recessed in the exhaust pipe assembly of the internal combustion engine Space preferably between two with respect to the flow direction of the exhaust gas provided upstream and downstream Arranged thresholds, in particular between the threshold and a another threshold, which provided at the edge of the recessed space is downstream in the flow direction of the exhaust gas is formed by the recessed space.

There the sleepers are provided at the edges of the recessed space are both upstream and downstream are formed in this way, exhaust gas and a swirled Flow from it or similar more reliable be prevented from entering the vicinity of the injection opening arrangement position to flow.

Farther is the recessed in the exhaust pipe assembly of the internal combustion engine Space preferably within a curved portion of the exhaust pipe or in the vicinity of the bent portion of the exhaust pipe.

For the case that the recessed space within the curved area the exhaust pipe or in the vicinity thereof may the recessed room due to design limitations of the exhaust pipe and the formation of the recessed space so arranged or be formed that it is likely that exhaust gas in the recessed room flows. In this case, however, too by the provision of the threshold and recessed portion described above be easily caused that it is unlikely that exhaust gas flows to the recessed space. Accordingly The additive may be present despite the presence of the above limitations regardless of the exhaust gas flow rate homogeneous in the exhaust gas be distributed.

Farther is the additive in the exhaust pipe assembly of the internal combustion engine preferably an additive for exhaust gas purification.

As a result the above-mentioned design and functionality can the additive for exhaust gas purification regardless of the Exhaust gas flow rate can be homogeneously distributed in the exhaust gas.

Farther the additive is in the exhaust pipe arrangement of the internal combustion engine preferably in the form of an aqueous solution.

at the additive as described above in the form of an aqueous Solution, it is likely to be on an exhaust pipe wall attaches before the water content evaporates, and it needs a certain time until the additive has dispersed in the exhaust gas. As described above, is for the distribution of the additive or the evaporation of the water content is left for some time, until the additive is transferred to the exhaust stream after it was injected from the supply valve. Therefore, even one can Additive for exhaust gas purification in the form of an aqueous solution independently be distributed homogeneously in the exhaust gas from the exhaust gas flow rate.

Farther is the additive in the exhaust pipe assembly of the internal combustion engine preferably an aqueous urea solution. The aqueous urea solution can be used as the additive in the form of an aqueous solution. Also when using the aqueous urea solution Urea can be independent of the flow rate of the exhaust gas be distributed homogeneously in the exhaust gas.

Farther In the exhaust pipe arrangement of the internal combustion engine, the internal combustion engine is preferably a diesel engine.

Of the Diesel engine can be considered as the internal combustion engine. The Exhaust gas can be sufficient regardless of the exhaust gas flow rate from the NOx and the like generated from the diesel engine will be cleaned.

BRIEF DESCRIPTION OF THE DRAWINGS

The Features, advantages and technical and industrial significance of this invention will become apparent in the following detailed description of embodiments of the invention with reference to the accompanying figures are described, wherein the same reference numerals denote the same elements. Show it:

1 a plan view of an exhaust pipe according to a first embodiment of the invention;

2 a cross-sectional view along the line AA in 1 ;

3 a perspective view of an essential part of the exhaust pipe according to the first embodiment of the invention;

4A and 4B Longitudinal views for explaining the operation and effect of the first embodiment of the invention;

5 a perspective view of an essential part of an exhaust pipe according to a second embodiment of the invention;

6 a perspective view of an essential part of an exhaust pipe according to a third embodiment of the invention;

7A a longitudinal sectional view of an exhaust pipe according to a fourth embodiment of the invention;

7B a longitudinal sectional view of an exhaust pipe according to a first modification example of the fourth embodiment of the invention; and

7C a longitudinal sectional view of an exhaust pipe according to a second modification example of the fourth embodiment of the invention.

DETAILED DESCRIPTION OF EXAMPLES

The first embodiment of the invention will be described with reference to FIGS 1 to 4A and 4B described. The 1 to 3 each show an additive injection area 4 in an exhaust pipe 2 a diesel engine. 1 is a top view. 2 is a cross-sectional view along the line AA in 1 , 3 is a perspective view of an essential part of 1 ,

Exhaust discharged from an exhaust port of a diesel engine becomes an additive injection region via an exhaust manifold as indicated by the solid arrows from the left side in the drawings 4 introduced and flows out to the right in the drawings. In this embodiment of the invention, the additive injection area 4 a curved area 4a of the exhaust pipe 2 on. In 2 Therefore, exhaust gas is introduced from a left upper area and flows out horizontally to the right side. Accordingly, an upper side of this additive injection area 4 in 2 equivalent to the inside of the bent portion 4a ,

Inside this curved area 4a is an injection opening disposition position 8th a supply valve 6 arranged. In this case, the injection opening disposition position is 8th continue in a recessed room 10 arranged on the inner surface of a pipe wall 4b within the curved area 4a is trained. This recessed room 10 is essentially in the middle of the curved area 4a or in the vicinity thereof (in this case, slightly downstream of an exhaust gas flow direction). The recessed room 10 However, it may be provided at a location where the exhaust pipe 2 straight in the additive injection area 4 further downstream. The recessed room 10 is formed in a shape which is obtained by bulging the pipe wall itself from the exhaust pipe to the outside.

Due to the above-mentioned structure, an exhaust gas purification additive becomes that of one in the injection opening disposition position 8th arranged injection port 6a in the supply valve 6 In this case, an aqueous urea solution, as indicated by the two-dot chain line, is injected into the recessed space 10 injected.

A dam or a threshold 14 that has a front surface 14a and which is diagonally or obliquely from the inner surface of the tube wall 4b is at the edge of the recessed space 10 formed, which is formed upstream with respect to a direction of the exhaust gas flow. As in the 1 and 3 is visible, is the threshold 14 in this embodiment of the invention at the upstream edge of the recessed space 10 substantially along half the circumference of the exhaust pipe 2 intended. This threshold 14 is formed in a shape which by pressing the pipe wall itself from the exhaust pipe 2 getting inside. It should be noted that the position of a shape of the pipe wall, which has no threshold 14 indicated by dashed lines.

In addition, a recess section 16 on an inner surface of a pipe wall 4c formed, which is the inner surface of the pipe wall 4b Opposite, at the threshold 14 is provided. This deepening section 16 is formed in a shape which by bulging a pipe wall of the exhaust pipe 2 even from the exhaust pipe 2 is obtained to the outside. It should be noted that the position of a shape of the pipe wall that no recess section 16 indicated by dashed lines. In this embodiment of the invention, the degree of depression of the recess portion corresponds 16 the degree of increase in the threshold 14 ,

When exhaust gas at a high speed of the diesel engine or the like at a high speed through the above-described additive injection range 4 flows, it flows along a direction of the pipeline to one immediately before the threshold 14 located point and then hits on the front surface 14a the threshold 14 , as in 4A shown. The exhaust stream therefore becomes oblique from the inside of the bent area 4a led away and changed its direction to the outside of the curved area 4a out.

The recess section 16 is outside the curved area 4a , in particular on the inner surface of a pipe wall 4c that's the threshold 14 opposite. The entire exhaust flow is therefore, just before it reaches the position of recessed space 10 reached on the front surface 14a the threshold 14 guided and changes its direction evenly to the outside. Thus, while the generation of a swirling flow is suppressed, the exhaust gas flows at the recessed space 10 past, as indicated by the solid arrows, and flows downstream of the additive injection area 4 , Accordingly, exhaust gas does not flow directly into the recessed space 10 one, and the one from the supply valve 6 in the recessed room 10 Injected, aqueous urea solution 12 is prevented from being on an inner surface 10a of the recessed room 10 or an inner surface of the pipe wall located downstream thereof 4d to stick.

Even when exhaust gas flows at a low speed of the diesel engine or the like at a low speed, it flows in the recessed space 10 over and flows due to the aforementioned operation of the threshold 14 and the recessed section 16 downstream of the additive injection area 4 instead of directly into the recessed room 10 to flow in, as in 4B shown. Therefore, the stick from the supply valve 6 in the recessed room 10 injected aqueous urea solution 12 even if the exhaust gas flows at a low speed, not on the inner surface 10a of the recessed room 10 or an inner surface of the pipe wall located downstream thereof 4d at.

As a comparative example in the event that the threshold 14 and the recessed section 16 are not provided, however, exhaust gas flows, especially when it flows at a low speed, in the recessed space 10 and push as shown by the dashed arrows in 4B indicated, directly with the aqueous urea solution 12 together, which causes the aqueous urea solution 12 on the inner surface 10a of the recessed room 10 or an inner surface of the pipe wall located downstream thereof 4d adheres. When the exhaust gas flow rate is small, the injection amount of the urea aqueous solution 12 also correspondingly low. This adhesion of the aqueous urea solution 12 is therefore considerable.

The state in which the aqueous urea solution 12 is adhered to, is a state in which the aqueous urea solution 12 to the side of the recessed room 10 in the exhaust pipe 2 tends towards. The adhering aqueous urea solution 12 or urea particles after evaporation of the water content are mixed in an unbalanced state with the exhaust gas and flow to a downstream catalyst. In this embodiment of the invention, however, this unbalanced state is prevented.

• (i) Wie oben beschrieben, kann die wässrigen Harnstofflösung 12, die in einer entsprechend geringen Menge eingespritzt wird, aufgrund der Schwelle 14 und des Vertiefungsabschnitts 16 sowohl für den Fall, dass die Abgasdruchflussrate in dem Verbrennungsmotor niedrig ist, als auch für den Fall, dass die Abgasdurchflussrate in dem Verbrennungsmotor hoch ist, ausreichend in dem vertieften Raum 10, in den das kein Abgas einströmt, verteilt werden. Insbesondere da die vordere Oberfläche 14a der Schwelle 14 bezüglich der Innenfläche der Rohrwand 4b schräg erhoben ist, wird die Erzeugung einer verwirbelten Strömung unterdrückt, um Abgas zuverlässiger daran zu hindern, in den vertieften Raum 10 einzuströmen. Daher haftet die wässrigen Harnstofflösung 12 nicht sofort an der Innenfläche (10a, 4d) des Abgasrohrs an.

The following effects are achieved according to the first embodiment of the invention described above.

• (i) As described above, the urea aqueous solution 12 , which is injected in a correspondingly small amount, due to the threshold 14 and the recessed section 16 both in the case where the exhaust gas exhaust flow rate in the internal combustion engine is low and in the case where the exhaust gas flow rate in the internal combustion engine is high enough in the recessed space 10 into which no exhaust gas flows are distributed. Especially since the front surface 14a the threshold 14 with respect to the inner surface of the pipe wall 4b is raised obliquely, the generation of a turbulent flow is suppressed to more reliably prevent exhaust gas in the recessed space 10 to flow. Therefore, the aqueous urea solution adheres 12 not immediately on the inner surface ( 10a . 4d ) of the exhaust pipe.

Accordingly, the aqueous urea solution becomes 12 in the recessed room 10 and then from an interface between the recessed space 10 and the exhaust gas stream and conveyed to the downstream catalyst (SCR catalyst). Therefore, the aqueous urea solution 12 or homogeneously distributing resulting urea particles even at a low exhaust gas flow rate instead of being distributed unbalanced in the exhaust gas. In this way, urea can be distributed homogeneously in the exhaust gas independently of the exhaust gas flow rate as an additive for exhaust gas purification.

In particular, when urea is present as an aqueous urea solution, it is likely to be on the inside surface 10a . 4d adheres to the exhaust pipe. Therefore, as described above, despite the time required for the evaporation of the water content for the distribution of the additive and the evaporation of the water content, a certain time is left until the additive after injection from the supply valve 6 is conveyed into the exhaust stream. Thus, the additive for exhaust gas purification can be distributed homogeneously in the exhaust gas even in the form of an aqueous solution, regardless of the exhaust gas flow rate.

• (ii) Insbesondere da die Schwelle 14 an dem Rand des vertieften Raums 10 ausgebildet ist, welcher bezüglich einer Richtung des Abgasstroms stromaufwärts ausgebildet ist, kann um die Anordnungsposition des Zufuhrventils 6 herum ein ausreichender Raum gewährleistet werden, in den kein Abgas einströmt. Dementsprechend kann der Effekt einer homogenen Verteilung des Additivs zur Abgasreinigung in dem Abgas unabhängig von der Abgasdurchflussrate zusätzlich verstärkt werden.
• (iii) Der vertiefte Raum 10 ist innerhalb des gebogenen Bereichs 4a des Abgasrohrs 2 oder innerhalb der Umgebung des gebogenen Bereichs 4a ausgebildet. Da er so angeordnet ist, kann der vertiefte Raum 10 aufgrund von Einschränkungen bei der Gestaltung des Abgasrohrs 2, der Formung des vertieften Raums 10 oder ähnlichem so angeordnet oder ausgebildet sein, dass ein Einströmen von Abgas in diesen wahrscheinlich ist. In diesem Fall kann jedoch ebenfalls durch das oben beschriebene Vorsehen der Schwelle 14 und des Vertiefungsabschnitts 16 auf einfache Weise bewirkt werden, dass es unwahrscheinlich ist, dass Abgas zu dem vertieften Raum 10 strömt. Dementsprechend kann das Additiv trotz des Vorhandenseins der obigen Einschränkungen unabhängig von der Abgasdurchflussrate homogen in dem Abgas verteilt werden.
• (iv) Die Schwelle 14 wird in einer Form ausgebildet, welche durch Einpressen einer Rohrwand von dem Abgasrohr 2 selbst von dem Abgasrohr 2 nach innen erhalten wird, und der Vertiefungsabschnitt 16 wird in einer Form ausgebildet, welche durch Auswölben einer Rohrwand von dem Abgasrohr 2 selbst von dem Abgasrohr 2 nach außen erhalten wird. Dementsprechend können diese Komponenten ausgebildet werden, ohne weitere spezielle Elemente außer der Rohrwand anzuordnen. In Folge dessen kann sowohl die Abgasrohr-Anordnung vereinfacht als auch ein Beitrag zur Verringerung des Gewichts geleistet werden.

The exhaust gas can therefore be from the NOx and similar, which is generated by the diesel engine, regardless of the exhaust gas flow rate to be sufficiently cleaned.

• (ii) Especially as the threshold 14 at the edge of the recessed room 10 is formed, which is formed upstream with respect to a direction of the exhaust gas flow, can by the arrangement position of the supply valve 6 around a sufficient space can be ensured, in which no exhaust gas flows. Accordingly, the effect of homogeneous distribution of the exhaust gas purification additive in the exhaust gas can be additionally enhanced regardless of the exhaust gas flow rate.
• (iii) The recessed room 10 is inside the curved area 4a of the exhaust pipe 2 or within the vicinity of the curved area 4a educated. Since it is so arranged, the recessed space can 10 due to limitations in the design of the exhaust pipe 2 , the shaping of the recessed space 10 or the like may be so arranged or formed that an inflow of exhaust gas is likely in these. In this case, however, can also by the above-described provision of the threshold 14 and the recessed section 16 In a simple way, it causes it to be unlikely that exhaust gas reaches the recessed space 10 flows. Accordingly, the additive can be homogeneously distributed in the exhaust gas regardless of the exhaust gas flow rate despite the existence of the above restrictions.
• (iv) The threshold 14 is formed in a mold which by pressing a pipe wall of the exhaust pipe 2 even from the exhaust pipe 2 is obtained inside, and the recess section 16 is formed in a shape which by bulging a pipe wall of the exhaust pipe 2 even from the exhaust pipe 2 is obtained to the outside. Accordingly, these components can be formed without arranging other special elements except the pipe wall. As a result, both the exhaust pipe arrangement can be simplified and a contribution to reducing the weight can be made.

Hereinafter, a second embodiment of the invention will be described with reference to FIG 5 described. 5 Fig. 16 is a perspective view of an essential part of the structure of an additive injection area 104 in an exhaust pipe 102 according to this embodiment of the invention. In this embodiment of the invention, both ends of a threshold extend 114 to the two respective side portions of an injection opening disposition position 108 , That is, the threshold 114 consists of one at the edge of a recessed room 110 , which is formed upstream with respect to the flow direction of the exhaust gas, arranged front threshold 114a , and from side thresholds 114b on both sides of the recessed room 110 are formed. Although she is in 5 behind the injection opening disposition position 108 is not visible, is the side threshold 114b also on the other side of the in 5 shown in the foreground side threshold with respect to the Einspritzöffnungsanordnungsposition 108 ,

• (i) Zusätzlich zu den Effekten der vorhergehenden ersten Ausführungsform der Erfindung kann Abgas daran gehindert werden, von beiden Seiten des vertieften Raums 110 einzuströmen, um die Funktionsweise der Verhinderung eines Einströmens von Abgas in die Umgebung der Einspritzöffnungsanordnungsposition 108 zu verstärken, da die seitlichen Schwellen 114b durchgehend auf beiden Seiten der vorderen Schwelle 114a ausgebildet sind.

The second embodiment of the invention is to the first embodiment of the invention in other design details, such as those of a recessed portion 116 and the like, identical. The following effects are achieved according to the second embodiment of the invention described above.

• (i) In addition to the effects of the foregoing first embodiment of the invention, exhaust gas can be prevented from both sides of the recessed space 110 to flow to the operation of preventing the flow of exhaust gas into the vicinity of the injection opening disposition position 108 to reinforce, since the lateral thresholds 114b continuous on both sides of the front threshold 114a are formed.

Hereinafter, a third embodiment of the invention will be described with reference to FIG 6 described. 6 Fig. 16 is a perspective view of an essential part of the structure of an additive injection area 204 in an exhaust pipe 202 according to this embodiment of the invention. A threshold 214 extends further in this embodiment of the invention, as in the previous second embodiment, and is at an edge of a recessed space 210 formed along an entire circumference of this. In 6 There is one behind the injection opening disposition position 208 unseen side threshold 214 also on the side that the in 6 in the foreground side, on which the side sill is along the injection opening disposition position 208 is arranged.

• (i) Zusätzlich zu den Effekten der vorhergehenden zweiten Ausführungsform der Erfindung kann Abgas zuverlässiger daran gehindert werden, in die Umgebung der Einspritzöffnungsanordnungsposition 208 einzuströmen, da die Schwelle 214 den Rand des vertieften Raums 210 entlang seines gesamten Umfangs umgibt.

The third embodiment of the invention is to the foregoing first embodiment of the invention in other design details, such as those of a recessed portion 216 and the like, identical. The following effects are achieved according to the third embodiment of the invention described above.

• (i) In addition to the effects of the foregoing second embodiment of the invention, exhaust gas can be more reliably prevented from entering the vicinity of the injection port disposition position 208 flow in, as the threshold 214 the edge of the recessed room 210 surrounds along its entire circumference.

Hereinafter, a fourth embodiment of the invention will be described with reference to FIG 7 described. 7A FIG. 15 is a longitudinal sectional view of a structure of an additive injection area. FIG 304 in an exhaust pipe 302 according to this embodiment of the invention. In this embodiment of the invention, there is no recessed space at an injection opening disposition position 308 intended. As in 7A is shown, is a supply valve 306 arranged so that an aqueous solution of an additive for exhaust gas purification (in this case, an aqueous urea solution) 312 from an injection port 306a in the exhaust pipe 302 is injected. A threshold 314 is upstream of this injection opening disposition position with respect to a direction of the exhaust gas flow 308 educated.

The fourth embodiment of the invention is identical to the previous first embodiment of the invention in other design details. That is, the injection opening disposition position 308 of the supply valve 306 is inside a curved area 304a of the additive injection area 304 intended. This injection opening disposition position 308 is essentially in the middle of the curved area 304a or arranged with respect to a direction of the exhaust stream slightly downstream thereof. The injection opening disposition position 308 however, may be provided further downstream at a location where the exhaust pipe is located 302 extends in a straight line.

It should be noted here that the aqueous solution of an additive for exhaust gas purification 312 which from an injection port 306a of the injection opening disposition position 308 provided supply valve 306 is injected, as indicated by the double-dotted lines, in a space in the exhaust pipe 302 at the injection opening disposition position 308 is injected.

A threshold 314 that has a front surface 314a which extends from an inner surface of a pipe wall 304b rises obliquely and thus from the inner surface of the pipe wall 304b is protruding upstream of the injection opening disposition position with respect to a direction of the exhaust gas flow 308 arranged. This threshold 314 is formed in a shape which by pressing the pipe wall of the exhaust pipe 302 even from the exhaust pipe 302 getting inside. It should be noted that the position of a shape of the pipe wall is not a threshold 314 has indicated by dashed lines.

Furthermore, a recess portion 316 on an inner surface of the pipe wall 304c that is the inner surface of the pipe wall 304b on which the threshold 314 is provided, opposite, trained. This deepening section 316 is formed in a shape which by bulging a pipe wall of the exhaust pipe 302 even from the exhaust pipe 302 is obtained to the outside. It should be noted that the position of a shape of the pipe wall that no recess section 316 indicated by dashed lines. In this embodiment of the invention, the degree of depression of the recess portion corresponds 316 the degree of increase in the threshold 314 ,

If in the additive injection range described above 304 Exhaust gas flows at a high speed of the diesel engine or the like at a high speed, it flows along a direction of the pipeline to one immediately before the threshold 314 point and then hits the front surface 314a the threshold 314 as shown by the solid arrows. The exhaust stream therefore becomes oblique from the inside of the bent area 304a led away and changes its direction to the outside of the curved area 304a out.

The recess section 316 is outside on the curved area 304a , in particular on the inner surface of a pipe wall 4c that's the threshold 314 opposite. The entire exhaust flow is therefore, before taking the place of the room 310 at the injection opening disposition position 308 reached on the front surface 314a the threshold 314 guided and changes its direction to the outside.

Thus, since the generation of a swirling flow is suppressed, the exhaust gas flows to the space 310 past, as indicated by the solid arrows, and flows downstream of the additive injection area 304 , Accordingly, the exhaust gas directly flows to the injection opening disposition position 308 , and that of the supply valve 306 in the room 310 Injected aqueous solution of an additive for exhaust gas purification 312 is prevented from being on an inner surface of the pipe wall 308a the injection opening disposition position 308 or an inner surface of the pipe wall located downstream thereof 304d to stick. This also applies when the exhaust gas flows at a low speed in the diesel engine.

In the event, however, that threshold 314 and the recessed section 316 are not provided, as indicated by the dashed lines as a comparative example, the exhaust gas flow, especially when exhaust gas flows at a low speed, directly with the aqueous solution of an additive for exhaust gas purification 312 together, which causes the aqueous solution of an additive to purify the exhaust gas 312 on the inner surface of the pipe wall 308a the injection opening disposition position 308 and the downstream surface of the pipe wall 304d adheres. In In this state of adhesion, the aqueous solution of an additive for exhaust gas purification tends 312 to the injection port arranging position side 308 of the exhaust pipe 302 and the adhered aqueous solution of an additive for exhaust gas purification 312 or the particles of the exhaust gas purification additive after the evaporation of the water content are mixed with the exhaust gas in an unbalanced state and flow to a downstream catalyst. In this embodiment of the invention, however, this unbalanced state is prevented. Accordingly, the effects of the foregoing first embodiment of the invention are made in other respects, although no recessed space is provided.

Hereinafter, a first modification of the fourth embodiment of the invention will be described with reference to FIG 7B described. An exhaust pipe 402 , this in 7B is shown in a longitudinal sectional view, with respect to a flow direction of the exhaust gas upstream of an injection opening arrangement position 408 in an additive injection area 404 arranged threshold 414 on, with both ends of the threshold 414 on both side portions of the injection opening disposition position 408 extend. Accordingly, compared to 7A Exhaust gas can be prevented from being laterally into a room 410 in the exhaust pipe 402 at the injection opening disposition position 408 to flow to the operation of preventing the flow of exhaust gas into the vicinity of the injection opening disposition position 408 to reinforce.

Hereinafter, a second modification of the fourth embodiment of the invention will be described with reference to FIG 7C described. An exhaust pipe 502 , this in 7C is shown in a longitudinal sectional view, has a threshold 514 which is arranged to have an injection opening disposition position 508 along its entire circumference in an additive injection area 504 surrounds. Thus, compared to the 7A and 7B Exhaust gas can be reliably prevented from entering the vicinity of the injection opening arrangement position 508 to stream.

• (a) In jeder der vorhergehenden Ausführungsformen der Erfindung ist das Beispiel eines Abgasrohrs eines Dieselmotors dargestellt. Die Erfindung ist jedoch auch auf einen Fall anwendbar, bei dem ein Additiv zum Zweck einer Abgasreinigungsbehandlung bei einem Benzinmotor in ein Abgasrohr eingespritzt wird, und kann dabei ähnliche Effekte bewirken.
• (b) Zusätzlich kann im Hinblick auf eine Verstärkung des Effekts einer homogenen Verteilung eines Additivs eine gitterförmige oder netzförmige Verteilungsplatte unmittelbar unterhalb eines Additiv-Einspritzbereichs vorgesehen sein.
• (c) Obwohl die wässrige Harnstofflösung als Additiv angeführt wird, kann ein Reduktionsmittel wie zum Beispiel ein Kohlenwasserstoff oder dergleichen als Additiv im Falle eines NOx-Okklusions- und Reduktionskatalysators verwendet werden. In diesem Fall kann das Additiv ebenfalls durch Anwendung der Erfindung unabhängig von der Durchflussrate des Abgases homogen in dem Abgas verteilt werden. Ähnliche Effekte können auch bei der Verwendung von anderen Additiven bewirkt werden.
• (d) In jeder der in 6 und 7C gezeigten Ausführungsformen der Erfindung ist die Schwelle so ausgebildet, dass sie die Einspritzöffnungsanordnungsposition entlang ihres gesamten Umfangs umgibt. Es ist jedoch auch möglich, einen Aufbau zu verwenden, bei dem zwei Schwellen in Strömungsrichtung des Abgases stromaufwärts und stromabwärts der Einspritzöffnungsanordnungsposition angeordnet sind und keine Schwellen in einem zu der Strömungsrichtung des Abgases parallelen Bereich vorgesehen sind. Durch das in Strömungsrichtung des Abgases stromaufwärtige und stromabwärtige Anordnen der Schwelle kann somit Abgas sowie eine verwirbelte Strömung davon oder ähnliches zuverlässiger daran gehindert werden, in die Umgebung der Einspritzöffnungsanordnungsposition einzuströmen.

In the following, further embodiments of the invention will be described.

• (a) In each of the foregoing embodiments of the invention, the example of an exhaust pipe of a diesel engine is illustrated. However, the invention is also applicable to a case where an additive for the purpose of exhaust gas purification treatment in a gasoline engine is injected into an exhaust pipe, and can cause similar effects.
• (b) In addition, in view of enhancing the effect of homogeneous distribution of an additive, a lattice-shaped or meshed distribution plate may be provided immediately below an additive injection region.
• (c) Although the aqueous urea solution is mentioned as an additive, a reducing agent such as a hydrocarbon or the like may be used as an additive in the case of a NOx occluding and reducing catalyst. In this case, too, the additive can be homogeneously distributed in the exhaust gas by use of the invention regardless of the flow rate of the exhaust gas. Similar effects can also be achieved with the use of other additives.
• (d) In each of the in 6 and 7C In the illustrated embodiments of the invention, the threshold is configured to surround the injection port locating position along its entire circumference. However, it is also possible to use a structure in which two thresholds are arranged in the flow direction of the exhaust gas upstream and downstream of the injection opening arrangement position and no thresholds are provided in an area parallel to the flow direction of the exhaust gas. Thus, by arranging the threshold upstream and downstream in the flow direction of the exhaust gas, exhaust gas and a swirling flow thereof or the like can be more reliably prevented from flowing into the vicinity of the injection opening disposition position.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - JP 2007-332797 [0002, 0003, 0006, 0009]
• - JP 2006-77691 [0002, 0004, 0007, 0009]
• - JP 2008-128048 [0002, 0005, 0008, 0009]

Claims (18)

Exhaust pipe arrangement of an internal combustion engine with an exhaust pipe ( 2 . 102 . 202 . 302 . 402 . 502 ) into which an additive from a supply valve ( 6 . 306 ), characterized in that it comprises: a threshold ( 14 . 114 . 214 . 314 . 414 . 514 ), which in the flow direction of the exhaust gas in the exhaust pipe ( 2 . 102 . 202 . 302 . 402 . 502 ) upstream of an injection opening disposition position (FIG. 8th . 108 . 208 . 308 . 408 . 508 ) of the supply valve ( 6 . 306 ) from an inner surface of a pipe wall ( 4b . 304b ) and a recessed section ( 16 . 116 . 216 . 316 ), which on an inner surface of a pipe wall ( 4c . 304c ) is provided, which the inner surface of the pipe wall ( 4b . 304b ) at which the threshold ( 14 . 114 . 214 . 314 . 414 . 514 ) in the exhaust pipe ( 2 . 102 . 202 . 302 . 402 . 502 ) is provided. Exhaust pipe arrangement of an internal combustion engine according to claim 1, characterized in that the threshold ( 14 . 114 . 214 . 314 . 414 . 514 ) one of the flow direction of the exhaust gas opposite and with respect to the inner surface of a pipe wall ( 4b . 304b ) has diagonally uplifting front surface. Exhaust pipe arrangement of an internal combustion engine according to claim 1 or 2, characterized in that the threshold ( 14 . 114 . 214 . 314 . 414 . 514 ) is formed in a shape that by pressing a pipe wall itself from the exhaust pipe ( 2 . 102 . 202 . 302 . 402 . 502 ) inside. Exhaust pipe arrangement of an internal combustion engine according to one of claims 1 to 3, characterized in that the recessed portion ( 16 . 116 . 216 ) is formed in a shape that by bulging a pipe wall itself from the exhaust pipe ( 2 . 102 . 202 . 302 . 402 . 502 ) is obtained to the outside. Exhaust pipe arrangement of an internal combustion engine according to one of claims 1 to 4, characterized in that both ends of the threshold ( 114 . 414 ) to both sides ( 114b ) of the injection opening disposition position (FIG. 108 . 408 ). Exhaust pipe arrangement of an internal combustion engine according to one of claims 1 to 4, characterized in that both ends of the threshold ( 214 . 514 ) in the flow direction of the exhaust gas downstream to the injection opening arrangement position ( 208 . 508 ) to surround. An exhaust pipe arrangement of an internal combustion engine according to any one of claims 1 to 4, characterized in that the injection opening arrangement position between two upstream and downstream thresholds is arranged, in particular between the threshold and another threshold, which is provided so that they downstream in the flow direction of the exhaust gas from the injection opening disposition position of an inner surface of a pipe wall ( 4b . 304b protruding). Exhaust pipe arrangement of an internal combustion engine according to one of claims 1 to 7, characterized in that the injection opening arrangement position ( 8th . 108 . 208 . 308 . 408 . 508 ) within a bent region of the exhaust pipe ( 2 . 102 . 202 . 302 . 402 . 502 ) or in the vicinity of the bent region of the exhaust pipe ( 2 . 102 . 202 . 302 . 402 . 502 ) is arranged. Exhaust pipe arrangement of an internal combustion engine according to one of claims 1 to 4, characterized in that the injection opening arrangement position ( 8th . 108 . 208 ) in a on the inner surface of the pipe wall ( 4b ) formed recessed space ( 10 . 110 . 210 ), and the threshold ( 14 . 114 . 214 ) at the edge of the recessed space ( 10 . 110 . 210 ), which is arranged upstream in the flow direction of the exhaust gas. Exhaust pipe arrangement of an internal combustion engine according to claim 9, characterized in that the recessed space ( 10 . 110 . 210 ) is formed in a shape which by bulging a pipe wall itself from the exhaust pipe ( 2 . 102 . 202 ) is obtained to the outside. Exhaust pipe arrangement of an internal combustion engine according to claim 9 or 10, characterized in that both ends of the threshold ( 114 ) in the flow direction of the exhaust gas downstream to the respective side regions of the recessed space ( 110 ). Exhaust pipe arrangement of an internal combustion engine according to one of claims 9 or 10, characterized in that both ends of the threshold ( 214 ) along the recessed space ( 210 ) to annularly surround its entire circumference. Exhaust pipe arrangement of an internal combustion engine according to claim 9 or 10, characterized in that the recessed space ( 110 ) is arranged between two upstream and downstream thresholds of the exhaust gas, in particular between the threshold and another threshold located at the edge of the recessed space ( 110 ) is provided, which in the flow direction of the exhaust gas downstream of the recessed room ( 110 ) is provided. Exhaust pipe arrangement of an internal combustion engine according to one of claims 9 to 13, characterized in that the recessed space ( 110 ) within a bent region of the exhaust pipe ( 2 . 102 . 202 ) or in the vicinity of the bent region of the exhaust pipe ( 2 . 102 . 202 ) is arranged. Exhaust pipe arrangement of an internal combustion engine after one of claims 1 to 14, characterized in that the additive is an additive for exhaust gas purification. Exhaust pipe arrangement of an internal combustion engine after Claim 15, characterized in that the additive in the form of a aqueous solution is present. Exhaust pipe arrangement of an internal combustion engine after Claim 16, characterized in that the additive is an aqueous Urea solution is. Exhaust pipe arrangement of an internal combustion engine after one of claims 1 to 17, characterized in that the internal combustion engine is a diesel engine.