EP2960481A1 - Mixing device for charge air supply and exhaust gas recirculation - Google Patents

Abstract

The invention relates to a mixing device, by means of which charge air and recirculated exhaust gas can be supplied as charge air exhaust gas mixture of an internal combustion engine of a vehicle, comprising a flow-through line for the supplied charge air and an inflow line for recirculated exhaust gas, via a line connection region, comprising at least one passage opening (8), opens into a designed as a mixing section of the flow-through. An end section (5) of the inflow line (4) encloses by means of two legs (5a, 5b), which each form a semi-annular channel for the exhaust gas, the at least one passage opening (8) and surrounds the throughflow line (2, 3) in the line connection area (11 ) on the outer circumference at least partially. The inflow line (4) has, in the line connection region (11), a flow variation section (7) designed so that an exhaust gas flow through the flow variation section (7) is deflected at least partially into the two semi-annular channels formed by the legs (5a, 5b) ,

Description

The invention relates to a mixing device, by means of which charge air and recirculated exhaust gas can be supplied as charge air exhaust gas mixture of an internal combustion engine of a vehicle, comprising a flow-through for the supplied charge air and a feed line for recirculated exhaust gas, which opens via a line connection region in a formed as a mixing section of the flow-through ,

Such mixing devices are also referred to as charge air manifolds with integrated recirculated exhaust gas mixer. From the practice of generic mixing devices are known in which the inflow end end in the line connection area cylindrical or conical mixer or so-called. Flower mixer has inserted through a through hole in the flow line and there must be supported by means of additional fasteners.

The disadvantage of this is that this multi-part design of the mixing device in the manufacture and assembly is costly. Furthermore, it was found by the inventors that the known mixing devices do not allow optimal mixing of the recirculated exhaust gas with the fresh air or charge air and thus ensure no adequate homogenization of the exhaust air-air mixture.

An undesirable consequence of the insufficient homogenization of the charge-air exhaust gas mixture is that with several cylinders, individuals are excessively fed with exhaust gas, which results in increased particle emission.

The DE 197 40 998 A1 describes a further mixing device, by means of which fresh air of an internal combustion engine of a motor vehicle can be fed. The mixing device has a passage opening in which an exhaust gas recirculation line is received. The exhaust gas recirculation line is determined here by means of a holding device on the inlet device. Between the holding device surrounding the exhaust gas recirculation line in the form of a sleeve and the exhaust gas recirculation line, a heat-insulating, air-filled intermediate space is formed. An end region of the holding device is welded to an end region of the exhaust gas recirculation line projecting into an interior of the inlet device.

A disadvantage of such a mixing device is the circumstance that the inlet device is exposed to approximately voltages when the exhaust gas recirculation line undergoes a particularly strong increase in temperature as a result of a passage of hot exhaust gas.

It is thus an object of the invention to provide an improved mixing device with which the disadvantages of conventional mixing devices can be avoided. The object of the invention is, in particular, to provide a mixing device by means of which charge air and recirculated exhaust gas can be supplied as charge air exhaust gas mixture of an internal combustion engine of a vehicle, which can be produced cost-effectively and brings about improved uniform distribution of the exhaust gas part in the charge air exhaust gas mixture.

These objects are achieved by a mixing device having the features of the main claim. Advantageous embodiments and applications of the invention are the subject matter of the dependent claims and are explained in more detail in the following description with partial reference to the figures.

It is proposed a mixing device, by means of which charge air or fresh gas and recirculated exhaust gas can be supplied as charge air exhaust gas mixture of an internal combustion engine of a vehicle. If appropriate, the term "fresh air" is used in the context of the present invention instead of the term "charge air". Both terms are to be regarded as synonymous in the context of the present invention.

The mixing device according to the invention comprises in accordance with the prior art, a flow-through for the supplied charge air and an inflow line for recirculated exhaust gas, which opens via a line connection region in a designed as a mixing section of the flow passage, wherein the connecting portion has at least one passage opening, preferably radially in Reference to the flow-through can be flowed through.

According to general aspects of the invention, an end section of the inflow line encloses the at least one passage opening by means of two legs, which each form a semi-annular channel for the exhaust gas. Further, the end portion surrounds the flow passage in the line connection region on the outer circumference at least partially by means of the two legs.

In the context of the invention, there is also the possibility that the two legs or semi-annular ring channels are fluidly connected to one another at their end regions lying in the flow direction of the exhaust gas such that a circumferential annular channel is formed.

Furthermore, the inflow line in the line connection region has a flow variation section which is embodied such that an exhaust gas flow through the flow variation section is deflected at least partially into the two semi-annular channels formed by the legs and then flows into the flow-through line substantially annularly via the at least one passage opening.

The special geometry of the mixing device for the exhaust gases, with which the internal combustion engine is equipped according to the invention, makes it possible to realize an intensive mixing of the charge air and the recirculated exhaust gases in the connection region of this mixing device, with the sufficient homogenization of the at the outlet from the mixing device Exhaust air mixture is ensured.

The flow change section is preferably arranged centrally in an end region of the inflow line on a peripheral section of the feed-through tube facing the feed tube.

According to an advantageous embodiment, the flow change section is designed as a flow divider, preferably as a flow web, which is arranged so that an exhaust gas stream at the flow web divides into two partial exhaust streams, which open via the at least one passage opening in the form of a mixing section part of the flow path two-way radially. The flow divider or flow web can in this case be arranged essentially concentrically with respect to the two legs forming the annular channels.

According to a further embodiment, the flow variation section can be embodied as a constriction or constriction of the inflow line, for example formed by two projections or flow edges arranged centrally in an end region of the inflow line and projecting into the flow path of the exhaust gas opposite one another at the top and bottom.

According to a preferred embodiment, the throughflow line in the connection region has a cross-sectional constriction. This causes a constriction of the charge air cross section in the connection area according to the principle of a Venturi nozzle and increases the inflow rate of the recirculated exhaust gas. Further, the mixing can be increased in this way, and thus a further improvement in the uniform distribution of the recirculated exhaust gas in the charge air stream can be achieved.

For a thorough mixing over the circumference of the charge air flow, it is also advantageous to form the at least one passage opening through an annular gap or through two opposite semi-annular gaps. However, it is also possible to provide a plurality of passage openings in the connection region between the inflow line and the throughflow line.

One possibility of the realization according to the invention provides that the end section of the inflow line is designed such that the two legs are arranged eccentrically to the throughflow line. From this, a distribution of the supplied exhaust gas corresponding to the installation space can be achieved over the circumference of the charge air flow.

The legs may be sickle-shaped.

An advantageous division of the exhaust gas flow into two partial exhaust gas streams can be achieved if, according to a further variant, an impact gas stream facing the side of the flow change section, z. As the flow ridge, is convex, so that disturbing turbulence avoided before entering the charge air stream or at least reduced.

The side of the flow web facing the throughflow line can be concave and form an inner wall part section of the throughflow line in the connection region.

According to another variant, there is the possibility that the at least one passage opening narrows at an end region in the flow direction of the exhaust gas, so that z. B. the distributed over the two annular gaps inflowing exhaust gas volume wherever possible with the same inflow velocity meets the charge air flow.

The mixing device may be formed as a one-piece molded part, which allows a cost-saving production.

Moreover, it is advantageous if at least the end section of the inflow line is integrally connected to the throughflow line in order to achieve a tight closure. Likewise, it is advantageous to design the inflow line and the throughflow line at least in the connection region as a one-piece molded part, preferably as a cast part, so that the mixing device can be produced in a cost-saving manner.

The invention further relates to a vehicle, in particular a utility vehicle, with a mixing device as disclosed herein.

Figur 1

eine perspektivische Ansicht der Mischvorrichtung gemäß einer Ausführungsform der Erfindung;

Figur 2

die perspektivische Ansicht der Figur 1 mittig in Axialrichtung durchgeschnitten;

Figur 3

die perspektivische Ansicht der Figur 1 mittig in Querrichtung durchgeschnitten;

Figur 4

eine Seitenansicht der Mischvorrichtung gemäß einer Ausführungsform der Erfindung;

Figur 5

eine Schnittansicht der Mischvorrichtung in Figur 4 gemäß dem Schnitt A-A;

Figur 6

eine Schnittansicht der Mischvorrichtung in Figur 5 gemäß dem Schnitt B-B; und

Figur 7

eine perspektivische Teilschnittansicht der Figur 1; und

Figur 8

eine perspektivische Teilschnittansicht einer weiteren Ausführungsform der Erfindung.

The preferred embodiments and features of the invention described above can be combined with one another as desired. Further details and advantages of the invention will be described below with reference to the accompanying drawings. Show it:

FIG. 1

a perspective view of the mixing device according to an embodiment of the invention;

FIG. 2

the perspective view of FIG. 1 cut centrally in the axial direction;

FIG. 3

the perspective view of FIG. 1 cut centrally in the transverse direction;

FIG. 4

a side view of the mixing device according to an embodiment of the invention;

FIG. 5

a sectional view of the mixing device in FIG. 4 according to the section AA;

FIG. 6

a sectional view of the mixing device in FIG. 5 according to section BB; and

FIG. 7

a partial perspective sectional view of FIG. 1 ; and

FIG. 8

a partial perspective sectional view of another embodiment of the invention.

The FIGS. 1 to 7 show one and the same mixing device 1, which is formed as a one-piece molded part.

Identical parts are provided with the same reference numerals in the figures, so that the different views of the mixing device 1 shown in the drawing can also be understood on their own.

The mixing device 1 represents a charge air manifold with integrated mixer for recirculated exhaust gas (EGR mixer), so that by means of the mixing device 1 charge air and recirculated Exhaust gas can be supplied as a charge air-exhaust gas mixture of an internal combustion engine (not shown) of a vehicle.

The mixing device 1 comprises a feed line 2, 3 for the supplied charge air B, with an inlet pipe 2 for the charge air supplied B and an outlet pipe 3 for the exhaust gas charge air mixture C. The mixing device 1 further comprises a feed line 4 for recirculated exhaust gas A, the over a line connection region 11 opens into the designed as a mixing section part 3 of the flow-through.

In the installed state, the inlet pipe 2 of the throughflow line is connected to a fresh air line (not shown) for the fresh air mass flow to the engine. The outlet pipe 3 is connected to an intake pipe (not shown) to the engine in which the fresh air-exhaust gas mixture flows out of the mixing device.

The removed from the exhaust line of the engine proportion of recirculated exhaust gas passes through a cooling section and enters the inflow line 4, which z. B. is connected in the installed state to an exhaust gas recirculation line, also not shown.

The inflow line 2 is formed at its beginning as a hollow cylindrical neck and formed in its end portion 5 so that it surrounds the inflow 4 on the outer circumference by means of two crescent-shaped legs 5a, 5b, each forming an annular channel for the exhaust, the eccentric to the flow-through 2, 3 is arranged.

FIG. 2 shows the perspective view of FIG. 1 cut centrally in the axial direction. It can be seen that the connecting region 11 has two radially through-flow through openings 8, which are formed as two semi-annular gaps. FIG. 2 also shows that the crescent-shaped legs 5a, 5b in the end region 5 of the inflow line 4 surround the throughflow line 2, 3 in the peripheral region of the at least one passage opening and form two annular channels, which open into the flow-through line 2, 3 via the passage openings 8.

In the connection region 11, the inflow line 4 has a flow web 7 acting as a flow divider, which is arranged in the end region of the supply line such that an exhaust gas stream at the flow web 7 divides into two partial exhaust streams A1, A2 which flow into the two throughflow openings 8 which can be radially flowed through formed as a mixing section part 3 of the flow-through double flow radially.

This is in the views of Figures 3 and 7 illustrated. The recirculated exhaust gas flow A, which enters the mixing device 1 via the inflow pipe 4, meets in the end region 5 of the inflow pipe 4 on a centrally arranged flow web 7, which is arranged transversely to the inflow direction of the exhaust stream, in order then to divide into two partial streams, which in run deflected direction according to the arrows A1 and A1 and enter the throughflow line 2, 3 of the mixing device 1, in which the fresh air circulates through the radial passage openings 8. There, the partial flows A1, A2 are detected by the charge air flow B and in this due to the uniform distribution of Abgaszströmströmung over the stomata 8 evenly distributed over the circumference annular mixed (not shown).

This inflow of the recirculated exhaust gases in the form of partial flows, which are introduced annularly and radially into the charge air stream flowing in the interior of the mixing device 1, causes an intensive mixing of these exhaust gases with the fresh air, wherein a homogenization of the exhaust gas distribution over the charge air flow is achieved leaves the mixing device 1 via the axial outlet pipe 3.

As in the FIGS. 1 to 3 recognizable and in the views of FIGS. 4 and 6 is shown more clearly, the flow-through 2, 3 in the connection region 11 a cross-sectional constriction 6. This causes a constriction of the charge air cross-section in the connection region according to the principle of a Venturi nozzle and increases the inflow rate of the recirculated exhaust gas. Further, the mixing can be increased in this way, and thus a further improvement in the uniform distribution of the recirculated exhaust gas in the charge air stream can be achieved.

As in the view of FIG. 5 can be seen well, the side facing the impinging exhaust gas flow side of the web 7 is convex, while the through-flow line 2, 3 facing side of the flow web 7 is concave and forms an inner wall portion of the flow passage in the connection area. It has already been mentioned above that the flow web 7 is arranged centrally in the end region 5 of the inflow line 4, which is formed in this region by two crescent-shaped legs 5a, 5b, which each form an annular channel for a partial exhaust gas flow over which the exhaust gas streams to the passage openings 8 are headed. FIG. 5 further shows that the flow-through line, the center of which is represented by the two upper crossing dotted lines, is arranged eccentrically to the legs 5a, 5b and the annular channels. The sectional view in FIG. 5 further shows the wall 9 of the inflow line.

The two semi-annular, in the flow direction circumferentially arranged at the same height passage column 8 narrow at an end portion 8a in the flow direction of the exhaust gas, which in FIG. 6 can be seen.

FIG. 8 shows a partial perspective sectional view of another embodiment 81 of the invention. Here, components having the same reference numerals correspond to the components of the previous figures and will not be described separately.

A peculiarity of this embodiment resides in that the end portion 85 of the supply pipe 4 located in the pipe connecting portion 811 has a flow changing portion formed as a constriction 87. This embodiment of the flow change section results in an annular passage opening 87, which is narrowed in a central region of the supply line.

The constriction 87 is formed by two projections or flow edges arranged in an end region of the inflow line, which project into the flow path of the exhaust gas opposite one another, at the top and bottom.

The constriction 87 forms two upper and lower semicircular passage opening edges partially enclosing the passage opening 88, in particular at a location facing the feed line 4, the height of which decreases in the flow direction of the deflected exhaust gas partial flows A1, A2. The constriction 87 or each of these passage opening edges is convex on a side of the constriction 87 facing the impinging exhaust gas flow, while the side of the constriction 87 facing the flow-through line 2, 3 is concave and forms an inner wall section of the throughflow line 2, 3 in the connection region.

The constriction 87 thus forms, as mentioned above, a passage opening section narrowed in the middle region of the feed line, through which a partial exhaust gas flow A3 essentially without first being deflected laterally opens into the part 3 of the throughflow line 2, 3 formed as a mixing section.

The constriction 87 in turn serves as a flow edge at which a part of the exhaust gas flow A is deflected. As a result, two partial exhaust gas streams A1, A2 flow into the two semi-annular channels formed by the legs 5a, 5b and open into the narrow passage opening section adjoining the larger passage opening sections in the part 3 of the throughflow line 2, 3 formed as a mixing section.

The above explanation using the three partial exhaust streams A1, A2 and A3 is intended only to illustrate the operation of the mixing device 81. The skilled worker is clear from the figures, that formed by the formation of the constriction 87 and the passage 88 formed thereby no three separate exhaust gas partial streams, but that the partial exhaust gas stream A3 merges at its lateral edge regions in the exhaust gas streams A1 and A2, so that a via the passage opening annularly distributed exhaust gas flow, which flows into the flow-through.

Although the invention has been described with reference to particular embodiments, it will be apparent to those skilled in the art that various changes may be made and equivalents may be substituted for without departing from the scope of the invention. In addition, many modifications can be made without leaving the associated area. Accordingly, the invention should not be limited to the disclosed embodiments, but the invention is intended to embrace all embodiments which fall within the scope of the appended claims.

LIST OF REFERENCE NUMBERS

1, 81

mixing device

2, 3

Durchströmleitung

4

inflow

5, 85

end

5a, 5b

Legs (ring channels)

6

Area of the flow-through line with a narrowed cross-section

7, 87

flow web

8, 88

Through opening

8a

end

9

wall

11, 811

connecting area

A

exhaust gas flow

A1, A2, A3

Partial exhaust gas stream

B

Charge air flow

C

Exhaust charge air mixture

Claims (12)

Mixing device (1; 81), by means of which charge air (B) and recirculated exhaust gas (A) can be supplied as charge air exhaust gas mixture (C) to an internal combustion engine of a vehicle, comprising: a throughflow line (2, 3) for the supplied charge air (B); and an inflow line (4) for recirculated exhaust gas (A), which via a line connection region (11; 811), comprising at least one passage opening (8), opens in a formed as a mixing section part (3) of the throughflow line (2, 3) an end section (5; 85) of the inflow line (4) by means of two legs (5a, 5b) which each form a semi-annular channel for the exhaust gas, which surrounds at least one passage opening (8; 88) and the throughflow line (2, 3) in FIG Wire connection region (11; 811) on the outer circumference at least partially surrounds, and the inflow line (4) in the line connection region (11; 811) has a flow variation section (7; 87) configured such that an exhaust gas flow through the flow variation section (7; 87) at least partially into the two through the legs (5a, 5b) trained semi-annular channels is deflected. Mixing device (1) according to claim 1, characterized (A) that the flow change section is designed as a flow divider (7) which is arranged so that an exhaust gas flow (A) at the flow divider (7) into two partial exhaust gas streams (A1, A2), which in the two by the legs (5a 5b) deflected semi-annular channels, and via the at least one passage opening (8) in the formed as a mixing section part (3) of the throughflow line (2, 3) opens in two columns; and or (B) that the flow change section is designed as a flow web (7). Mixing device (81) according to claim 1, characterized in that the flow change section is designed as a constriction (87) of the inflow line (4). Mixing device (1, 81) characterized by a cross-sectional constriction (6) of the throughflow line (2, 3) in the line connection region (11, 811). Mixing device (1; 81) according to one of the preceding claims, characterized in that the at least one passage opening is formed by an annular gap (88) or by two opposite semi-annular gaps (8). Mixing device (1, 81) according to one of the preceding claims, characterized in that the two legs (5a, 5b) are arranged eccentrically to the throughflow line (2, 3). Mixing device (1) according to claim 6, when dependent on claim 3, characterized in that the flow divider (7) is arranged substantially concentric with the two legs (5a, 5b). Mixing device (1, 81) according to one of the preceding claims, characterized in that a side of the flow changing section (8, 87), in particular of the flow web (7), facing the impinging exhaust gas flow is convex. Mixing device (1; 81) according to one of the preceding claims, characterized in that the at least one passage opening (8; 88) narrows at an end region (8a) in the flow direction of the exhaust gas. Mixing device (1, 81) according to one of the preceding claims, characterized in that the mixing device (1) is formed as a one-piece molded part. Mixing device (1; 81) according to one of the preceding claims, characterized (A) that at least the end portion (5) of the inflow line (4) with the flow line (2, 3) is integrally connected; and or (B) that the inflow line (4) and the flow-through line (2, 3) are formed at least in the line connection region (11) as a one-piece molded part. Vehicle, in particular commercial vehicle with a mixing device (1; 81) according to one of the preceding claims.

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