DE102014009416A1 - 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 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.

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.

The above described preferred embodiments and features of the invention are arbitrarily combinable with each other. Further details and advantages of the invention will be described below with reference to the accompanying drawings. Show it:

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

2 the perspective view of 1 cut centrally in the axial direction;

3 the perspective view of 1 cut centrally in the transverse direction;

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

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

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

7 a partial perspective sectional view of 1 ; and

8th a partial perspective sectional view of another embodiment of the invention.

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

Identical parts are given the same reference numbers in the figures, so that the different views of the mixing device shown in the drawing 1 are also understandable 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 includes a flow line 2 . 3 for the supplied charge air B, with an inlet pipe 2 for the supplied charge air B and an outlet pipe 3 for the exhaust gas charge air mixture C. The mixing device 1 further comprises an inflow line 4 for recirculated exhaust gas A, via a line connection area 11 in the formed as a mixing section part 3 the flow-through opens.

The inlet pipe 2 the flow-through is connected in the installed state to a (not shown) fresh air line for the fresh air mass flow to the engine. The outlet pipe 3 is connected to a (not shown) Saugrohrleitung to the engine, in which flows the fresh air-exhaust gas mixture from the mixing device connected.

The portion of recirculated exhaust gas removed from the exhaust line of the engine 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 region as a hollow cylindrical neck and in its end 5 designed to be the inflow line 4 on the outer circumference by means of two crescent-shaped legs 5a . 5b encompasses, each forming an annular channel for the exhaust, the eccentric to the flow-through 2 . 3 is arranged.

2 shows the perspective view of 1 cut centrally in the axial direction. It can be seen that the connection area 11 two radially through-flow openings 8th has, which are formed as two semi-annular column. 2 further shows that the crescent-shaped legs 5a . 5b in the end area 5 the inflow line 4 the flow-through line 2 . 3 enclose in the peripheral region of the at least one passage opening and form two annular channels, via the passage openings 8th in the flow line 2 . 3 lead.

The inflow line 4 points in the connection area 11 a flow web acting as a flow divider 7 which is arranged in the end region of the supply line so that an exhaust gas stream at the flow web 7 in two partial exhaust gas streams A1, A2 divides, via the two radially through-flow openings 8th in the formed as a mixing section part 3 The flow-through line opens two-fold radially.

This is in the views of 3 and 7 illustrated. The recirculated exhaust gas flow A flowing into the mixing device 1 over the inflow pipe 4 enters, meets in the end area 5 of the inflow pipe 4 on a centrally arranged flow web 7 , which is arranged transversely to the inflow direction of the exhaust gas flow, in order then to divide into two partial flows, which run in the deflected direction according to the arrows A1 and A1 and into the flow-through line 2 . 3 the mixing device 1 , in which the fresh air circulates, through the radial passage openings 8th enter. 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 8th evenly distributed over the circumference annular mixed (not shown).

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

As in the 1 to 3 recognizable and in the views of 4 and 6 is shown more clearly, has the flow line 2 . 3 in the connection area 11 a cross-sectional constriction 6 on. 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 5 can be seen well, the side facing the impinging exhaust gas flow side of the flow bar 7 convex, while the flow-through 2 . 3 facing side of the flow web 7 is concave and forms an inner wall portion of the flow-through in the connection region. It has already been mentioned above that the flow web 7 in the middle in the end area 5 the inflow line 4 arranged in this area by two crescent-shaped legs 5a . 5b is formed, each forming an annular channel for a partial exhaust gas flow over which the exhaust gas streams to the passage openings 8th be directed. 5 further shows that the flow-through line, the center of which is represented by the two upper crossing dotted lines, is eccentric to the legs 5a . 5b or the ring channels is arranged. The sectional view in 5 also shows the wall 9 the inflow line.

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

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

A special feature of this embodiment is that in the line connection area 811 located end portion 85 the supply line 4 a flow changing portion which is a constriction 87 is trained. 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 narrowing 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 to each other at the top and bottom.

The narrowing 87 forms in particular on one of the supply line 4 two facing the passage opening 88 partially enclosing upper and lower semicircular passage opening edges whose height decreases in the flow direction of the deflected partial exhaust gas streams A1, A2. The narrowing 87 or each of these Durchgangsöffnungsänder is on a side facing the incident exhaust gas flow side of the constriction 87 convex, while the flow-through 2 . 3 facing side of the narrowing 87 is concave and an inner wall portion of the flow-through 2 . 3 forms in the connection area.

The narrowing 87 Thus, as mentioned above, forms a through-passage section narrowed in the middle region of the supply line, through which a partial exhaust gas flow A3 essentially, without being deflected to the side, into the part designed as a mixing section 3 the flow line 2 . 3 opens.

The narrowing 87 in turn serves as a flow edge at which a portion of the exhaust stream A is deflected. As a result, two exhaust partial streams A1, A2 flow into the two through the legs 5a . 5b formed semi-annular channels and open on the narrow passage opening section subsequent larger passage opening portions in the formed as a mixing section part 3 the flow line 2 . 3 one.

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 serve. The skilled person is clear from the figures that through the formation of the constriction 87 and the passage formed thereby 88 no three separate exhaust gas substreams are generated, but that the exhaust gas substream A3 merges at its lateral edge regions in the exhaust gas streams A1 and A2, so that an over 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

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 19740998 A1 [0005]

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 flow-through line ( 2 . 3 ) for the supplied charge air (B); and an inflow line ( 4 ) for recirculated exhaust gas (A) via a line connection area (A) 11 ; 811 ), comprising at least one passage opening ( 8th ), in a formed as a mixing section part ( 3 ) of the flow line ( 2 . 3 ), wherein an end portion ( 5 ; 85 ) of the inflow line ( 4 ) by means of two legs ( 5a . 5b ), each forming a semi-annular channel for the exhaust gas, the at least one passage opening ( 8th ; 88 ) encloses and the flow line ( 2 . 3 ) in the line connection area ( 11 ; 811 ) on the outer circumference at least partially surrounds, and the inflow line ( 4 ) in the line connection area ( 11 ; 811 ) a flow changing section ( 7 ; 87 ), which is designed such that an exhaust gas flow through the flow change section (FIG. 7 ; 87 ) at least partially into the two by the legs ( 5a . 5b ) deflected semi-annular channels is deflected. Mixing device ( 1 ) according to claim 1, characterized in that (a) the flow-changing section is designed as a flow divider ( 7 ) is arranged, 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 ) are formed deflected semi-annular channels, and via the at least one passage opening ( 8th ) in the part formed as a mixing section ( 3 ) of the flow line ( 2 . 3 ) confluence; and / or (b) that the flow variation section as a flow web ( 7 ) is executed. Mixing device ( 81 ) according to claim 1, characterized in that the flow-changing section as a constriction ( 87 ) of the inflow line ( 4 ) is executed. Mixing device ( 1 ; 81 ) characterized by a cross-sectional constriction ( 6 ) of the flow line ( 2 . 3 ) in the line connection area ( 11 ; 811 ). Mixing device ( 1 ; 81 ) according to one of the preceding claims, characterized in that the at least one passage opening through an annular gap ( 88 ) or by two opposite semi-annular gaps ( 8th ) is formed. Mixing device ( 1 ; 81 ) according to one of the preceding claims, characterized in that the two limbs ( 5a . 5b ) eccentric to the flow line ( 2 . 3 ) are arranged. Mixing device ( 1 ) according to claim 6, when dependent on claim 3, characterized in that the flow divider ( 7 ) substantially concentric with the two legs ( 5a . 5b ) is arranged. Mixing device ( 1 ; 81 ) according to any one of the preceding claims, characterized in that a side of the flow changing section facing the impinging exhaust gas flow ( 8th ; 87 ), in particular the flow web ( 7 ), convex. Mixing device ( 1 ; 81 ) according to one of the preceding claims, characterized in that the at least one passage opening ( 8th ; 88 ) at an end region ( 8a ) narrows 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 molding. Mixing device ( 1 ; 81 ) according to one of the preceding claims, characterized in that (a) 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 line ( 2 . 3 ) at least in the line connection area ( 11 ) are formed as one-piece molding. Vehicle, in particular commercial vehicle with a mixing device ( 1 ; 81 ) according to any one of the preceding claims.

Images