DE10344217A1 - Fresh gas-guiding section of a fresh gas system for an internal combustion engine, especially in a motor vehicle, comprises a lateral inlet opening for recirculated exhaust gas from an exhaust gas recirculation unit of the engine - Google Patents

Abstract

Fresh gas-guiding section (18) of a fresh gas system (19) for an internal combustion engine comprises a lateral inlet opening for recirculated exhaust gas from an exhaust gas recirculation unit of the engine, and first fixing elements that interact with second fixing elements to fix the section onto a housing (2) of an exhaust gas cooler (1) of the exhaust gas recirculation unit. The housing contains a distribution channel (11) that communicates on the inlet side with an exhaust gas inlet (7) for the housing for non-cooled recirculated exhaust gas and on the outlet side with several cooling channels that open into the inlet opening of the section. The housing contains a coolant channel system (13) that is coupled to the cooling channels in a heat-transferring manner and contains a coolant.

Description

The The present invention relates to a fresh gas leading portion of a fresh gas system for one Internal combustion engine, in particular in a motor vehicle.

at Internal combustion engines are known to be a part of the exhaust gases at the Combustion process arise, due to the fresh gas system, so-called. Exhaust gas recirculation. With Help such exhaust gas recirculation can the Pollutant emissions of the internal combustion engine positively influenced become. Because the recirculated exhaust gases regularly very much much hotter are as the fresh gas supplied to the engine, it is expedient that recirculated exhaust gas to cool before its introduction into the fresh gas system. in this connection comes a cooler exhaust gas recirculation, short EGR cooler, for use. By the cooling the recirculated exhaust gases can for a damage be avoided in the intake system, which is usually not for the high temperatures the exhaust is designed and in particular made of plastic can. On the other hand, the cooling of the recirculated exhaust gases of the cylinders supplied Mass flow increases what has an advantageous effect on the performance of the internal combustion engine and their exhaust emissions improved.

The Coupling point between exhaust gas recirculation and Fresh gas system, ie the point at which the recirculated exhaust gases to the fresh gas mixed, usually has a complex structure, especially with regard to the tightness and the thermal Loading of components problems arise.

Here The invention aims to remedy this. The present invention is concerned with the problem, for the repatriation of Exhaust gases in the fresh gas system show an advantageous way.

This Problem is inventively the subject of the independent Claim solved. Advantageous embodiments are the subject of the dependent Claims.

The The present invention is based on the general idea of the EGR cooler and to form a section of the fresh gas system as a unitary assembly, wherein the portion has a lateral entrance opening through a housing attached thereto of the EGR cooler is closed, wherein inside the housing several cooling channels, which have a common distribution channel are fed with the recirculated exhaust gases, in the entrance opening open out. By this construction, an integration of the EGR cooler in the section of the fresh gas system or vice versa an integration reaches the section of the fresh gas system in the EGR cooler. In such a integral construction can be the transition between cooled, recirculated exhaust gases designed in the fresh gas system in terms of temperature and sealing particularly favorable so be up for the assembly can achieve a long service life.

at an advantageous embodiment can the housing Furthermore a bypass distribution channel containing the input side with a The exhaust inlet communicating connectable, with which also the Cooling channels feed Distribution channel communicating connectable. The bypass distribution channel communicates on the output side with several bypass channels, the On the output side also open into the inlet opening of the section. The Bypass channels deal with it in a way a coolant channel system, that for cooling the cooling channels formed in the housing is. With the help of such an embodiment, it is possible at a corresponding control of the distribution channel or the bypass distribution channel, the recirculated exhaust gases either through the distribution channel and thus through the cooling channels or through the bypass manifold and thus through the bypass channels. In certain operating conditions the internal combustion engine, in particular during a warm-up phase or in cold ambient temperatures, it may be beneficial to the recirculated exhaust gases not to cool, to bring the internal combustion engine to operating temperature faster or to heat the engine so far that their cooling circuit Heat on another heat consumer, such as B. an interior heating, can deliver. In this case, the recirculated exhaust gases on the Bypass distribution channel introduced into the bypass channels, causing the be called Combustion gases are substantially uncooled or at least less strong chilled in the fresh gas flow can enter. By integrating the bypass manifold and the bypass channels into the housing of the EGR cooler will also the degree of integration of the housing elevated.

A further increase in the degree of integration can be achieved for the housing by integrating a connection area for a bypass valve into the housing, in which connection area the distribution channel, the bypass distribution channel and an inlet channel connected to the exhaust inlet are brought together. In this embodiment, only a suitable bypass valve must be used in the connection area, which can be switched between a first switching position, in which it connects the inlet channel with the distribution channel, and a second switching position, in which it connects the inlet channel with the bypass distribution channel , The integration of such a connection area in the housing reduces the number the otherwise required seals and connections. Furthermore, this integration opens up the possibility of integrating the connection area or the bypass valve into the cooling channel system of the housing.

A additional Increasing the degree of integration can be achieved by: another connection area, namely a connection area for an exhaust gas recirculation valve, short EGR valve, into the housing is integrated. This connection area is in the inlet line placed so that there is a first connected to the exhaust inlet Branch of the inlet pipe and a connectable to the distribution channel second branch of the inlet pipe are merged. With the EGR valve the rate, ie the proportion of recirculated exhaust gases, in short the EGR rate, be set. By integrating a suitable connection area in the case Here, too, simplifies the installation of such an EGR valve. Elaborate seals and connections can also largely omitted here. Furthermore, here also offers the Possibility, the connection area or the EGR valve in the cooling duct system of the housing integrate. The cooling of the EGR valve or the bypass valve increases the life of the respective Valve.

by virtue of its high degree of integration, it is useful to the housing as forming an integral cast component, in particular of a light metal alloy, appropriate an aluminum alloy. For the production of the cast component is It worked with a lost form or "Lostform" is a relatively expensive manufacturing process, can be achieve cost advantages through the highly integrated design of the cooler since a number of assembly steps, fasteners and seals omitted.

Further important features and advantages of the invention will become apparent from the Dependent claims, from the drawings and from the associated description of the figures the drawings.

It it is understood that the above and the following yet to be explained features not only in the specified combination, but also in other combinations or alone, without to leave the scope of the present invention.

One preferred embodiment The invention is illustrated in the drawings and is in the following description explains the same reference numerals to the same or functionally identical or similar Refer to components.

It show, in each case schematically,

1 3 is a perspective view from the front of a section of a fresh gas system according to the invention with an EGR cooler arranged thereon, FIG.

2 a perspective view from behind of the arrangement according to 1 .

3 a perspective view from below of the EGR cooler without the section of the fresh gas system,

4 a top view of the EGR cooler,

5 a longitudinal section AA according to 4 .

6 a longitudinal section BB according to 4 .

7 a cross section CC according to 4 and

8th a cross section DD according to 4 ,

According to the 1 and 2 has an exhaust gas cooler 1 or EGR cooler 1 an exhaust gas recirculation device a housing 2 , a bypass valve 3 and a recirculation valve 4 or EGR valve 4 , The bypass valve 3 is here in a first connection area 5 used, the integral on the housing 2 is trained. Similarly, the EGR valve is 4 in a second connection area 6 built-in, which is also integral to the housing 2 is designed.

The housing 2 has an exhaust inlet 7 on, the z. B. may be connected to an exhaust manifold of an internal combustion engine, not shown. A first branch 8th an inlet pipe 9 leads to the second connection area 6 from which a second branch 10 the inlet pipe 9 to the first connection area 5 leads. From the first connection area 5 go a distribution channel 11 and a bypass manifold 12 from. The EGR valve 4 controls the flow from the first branch 8th to the second branch 10 and thus the rate of recirculated exhaust gases. In contrast, the bypass valve knows 3 in the embodiment shown here only two switching positions, namely a normal position, in which the inlet line 9 with the distribution channel 11 is connected, and a bypass position, in which the inlet conduit 9 with the bypass manifold 12 connected is.

Furthermore, the housing contains 2 a coolant channel system 13 of which in the 1 and 2 only a first connecting piece 14 , a second connection piece 15 and a connection channel 16 ( 2 ) are recognizable. This coolant channel system 13 is the preferred one shown here Embodiment designed so that it causes on the one hand the cooling of the recirculated exhaust gases and on the other additionally both a cooling of the first connection area 5 and the second connection area 6 allows. By cooling the connection areas 5 and 6 are also the valves 3 and 4 protected from the high temperatures of the recirculated exhaust gases, which also affects the valves 3 . 4 gives an increased lifetime.

The housing 2 is with its bottom 17 to a section 18 a fresh gas system only partially shown 19 connected. The preferred embodiment shown here is the section 18 to a fresh gas distributor, which is used in an internal combustion engine to distribute the supplied fresh gases to several cylinders, here four cylinders of the internal combustion engine. In 2 are four pairs of window-like fresh gas outlets 20 recognizable.

At the section 18 is also a flange 21 formed, the here four through insertion 22 as well as four through holes 23 having. Here are each cylinder or each pair outlet openings 20 an insertion opening 22 and a through hole 23 assigned. Before geous now is the case 2 with several, here with four flange elements 24 equipped, each one from the housing 2 facing away from the socket body 25 exhibit. Furthermore, on each flange element 24 one from the socket body 25 radially projecting contact surface 26 educated. In addition, each flange element contains 24 a central passage opening 27 which is also the socket body 25 penetrates centrally or coaxially. How out 2 is removable, are the socket body 25 into the insertion openings 22 of the flange 21 plugged in. To attach the housing 2 as well as the section 18 on a carrier component, not shown here, which may be, for example, an engine block of the internal combustion engine, can now conventional screws, from the in 1 shown front forth in the through holes 27 inserted and bolted to the carrier component. After tightening the screws is located at each flange element 24 a the respective insertion 22 bordering edge 28 between the respective carrier component and the contact surface 26 , As a result, a positive retention of the flange 21 on the respective carrier component via the flange elements 24 of the housing 2 reached. By a vote of the dimensions of the socket body 25 and the flange 21 In addition, a jamming or a press fit of the flange 21 be achieved on the support member.

The one with the section 18 the fresh gas system 19 coupled bottom 17 of the housing 2 extends here substantially in an unspecified plane and extends along a complementarily shaped portion of the section 18 , The section 18 contains in this area a lateral inlet opening 29 , in the 7 is recognizable. This entrance opening 29 is through the adjoining bottom 17 So through the case 2 laterally edged or closed. On the bottom 17 contains the housing 2 according to 3 outlet openings 30 from with the distribution channel 11 connected cooling channels 31 as well as outlet openings 32 from with the bypass manifold 12 connected bypass channels 33 , The said outlet openings 30 . 31 of the housing 2 they are all in the entrance opening 29 of the section 18 , That through the EGR cooler 1 recirculated exhaust gas is thus through the inlet 29 in the section 18 the fresh gas system 19 initiated.

The combination of EGR cooler shown here 1 and section 18 the fresh gas system 19 thus forms an integral assembly 39 , on the one hand the section 18 the fresh gas system 19 in the case 2 of the EGR cooler 1 is integrated. Because the section 18 is at the bottom 17 of the housing 2 cultivated and closes this or arranged there outlet openings 30 . 32 , On the other hand is also the EGR cooler 1 or his housing 2 in the section 18 the fresh gas system 19 integrated. Because the entrance opening 29 of the section 18 is through the at the entrance opening 29 adapted and at the section 18 attached housing 2 locked.

Corresponding 3 are at the bottom 17 of the housing 2 several outlet openings 30 a corresponding number of cooling channels 31 arranged side by side. In this case, there are eight cooling channels 31 provided, each with the distribution channel 11 communicate, with the individual cooling channels 31 to be flowed through in parallel. In the present case are for the eight cooling channels 31 six larger outlets 30 and two smaller outlet openings 30 ' to distinguish from each other. In the area of the smaller outlet openings 30 ' provided cooling channels 31 are the bypass channels 33 arranged, whose outlet openings 32 next to the outlet openings 30 respectively. 30 ' the cooling channels 31 are arranged.

With regard 3 is also noteworthy that at the bottom 17 of the housing 2 a completely closed, circumferential edge 34 is formed, the viewer, so the section 18 protrudes. This edge 34 encloses a heat sink 35 in which the outlet openings 30 . 32 or the cooling channels 31 are arranged. It is between the heat sink 35 and the edge 34 a groove 36 formed, an engagement for first fasteners 37 allows that on the section 18 are formed (see. 7 ). In the area of this groove 36 are then on the case 2 second fastening elements 38 formed with the said first fastening elements 37 interact to the section 18 on the housing 2 set. The second fastening elements 38 are here by one on the edge 34 formed, inwardly projecting projection formed (see, in particular 7 ).

How out 4 as well as from the 1 and 2 is removable, are the distribution channel 11 and the bypass manifold 12 outside on the heat sink 35 placed.

5 shows the longitudinal section AA according to 4 passing through the bypass manifold 12 is laid. According to 5 leads the bypass distribution channel 12 from the first connection area 5 parallel to the two bypass channels 33 in the entrance opening 29 of the section 18 open out.

In contrast, shows 6 the longitudinal section BB according to 4 passing through the distribution channel 11 is laid. Corresponding 6 leads the distribution channel 11 from the first connection area 5 parallel to the cooling channels 31 ,

Like that 5 and 6 can be seen, includes the coolant channel system 13 inside the heat sink 35 a variety of coolant channels 40 operating in the EGR cooler 1 be traversed by a liquid coolant. The coolant channels 40 Here are all so designed and arranged that they are the individual cooling channels 31 in the longitudinal sections of the 5 and 6 each border at least on two sides. In this case, the coolant channels extend 40 essentially over the entire length of the cooling channels 31 ,

6 also shows another coolant channel 45 passing through the second connection area 6 is guided to this or the EGR valve used therein 4 to cool.

7 shows the cross section CC according to 4 through one of the cooling channels 31 from the distribution channel 11 to its outlet 30 and thus to the inlet opening 29 of the section 18 leads.

In contrast, shows 8th the cross section DD according to 4 through one of the bypass channels 33 from the bypass distribution channel 12 to its outlet 32 leads.

According to the 7 and 8th are the cooling channels 31 designed so that for the guided therein exhaust gas flow from the distribution channel 11 to the respective outlet opening 30 respectively. 30 ' results in a multiple flow deflection. As a result, the flow path for the exhaust gas flow within the cooling channels 31 extended and the heat transfer between the exhaust gas flow and the exhaust gases exposed walls of the cooling channel 31 improved. The meandering course of the cooling channels 31 is achieved here by the fact that in each cooling channel 3l several, here three, cooling bars 41 are arranged, which are alternately from opposite walls 42 projecting transversely overlap each other by far, resulting in the desired meandering course of the cooling channels 31 leads.

The coolant channel system 13 is thus over the walls 42 and the cooling bars 41 heat transferring with the cooling channels 31 coupled.

Like that 7 and 8th is removable, are the coolant channels 40 also arranged so that they are the cooling channels 31 also include laterally in cross section. In this way, every single cooling channel 31 of coolant channels 40 bordered on four sides so that the coolant channel system 13 for every cooling channel 31 forms a cooling jacket. According to 8th this cooling jacket, so the coolant channel system wrapped 13 in the area of bypass channels 33 the respective bypass channel 33 together with the adjacent cooling channel 31 , which makes the case 2 also in the area of bypass channels 33 cooled to the outside. Like from the 5 and 8th It is particularly clear that the bypass channels are 33 considerably shorter and in particular straight, that is designed without flow deflection. This has compared to the cooling channels 31 a significantly shorter residence time for the exhaust gases in the bypass channels 33 result. The through the bypass channels 33 guided exhaust gas flow can thus not be cooled as much as the exhaust gas flow through the cooling channels 31 , The heat transfer coupling between the bypass channels 33 and the coolant channel system 13 is significantly weaker than between the coolant channel system 13 and the cooling channels 31 , In particular, stand at the bypass channels 33 considerably smaller cooled surfaces available.

Another special feature of the cooling channels 31 is seen in that a cross-sectional area in the outlet opening 30 respectively. 30 ' the cooling channels 31 is significantly larger than a cross-sectional area in the respective cooling channel 31 , In the embodiment shown here, the outlet cross-sectional area is also greater than the cross-sectional area in the distribution channel 11 and the cross-sectional area at a junction from the distribution channel 11 to the respective cooling channel 31 , This shaping leads in the area of the outlet opening 30 . 30 ' to a decrease in the speed of the now cooled exhaust gases. A reduced inlet velocity allows rapid mixing with the fresh gases, so that local overheating, so-called "hot spots" ver can be avoided. Furthermore, it is important that the cooling channels 31 are appropriately oriented so that at the outlet openings 30 respectively. 30 ' for the cooled exhaust gases sets a flow direction which is substantially transverse to a flow direction, which in the in section 18 led fresh gases prevails. This cross inflow also promotes rapid mixture formation and reduces the risk of hot spots.

In 7 is the section with broken lines 18 in a border area 43 indicated the entrance opening 29 surrounds. In the embodiment shown here, the first fastening elements 37 provided with locking contours, which the projections 38 in the groove 36 engage behind. This results in a detent or clip connection. In this coupling between housing 2 and section 18 is also a seal 44 integrated, whereby said coupling is gas-tight. Of particular importance here is that the coolant channels 40 of the coolant channel system 13 are designed so that they are between the cooling channels 31 and the coupling area, so the edge 43 the entrance opening 29 are arranged. This is the edge 43 and thus the section 18 quasi decoupled from the heat of the exhaust gas flow. In particular, this makes it possible to access the section 18 Made of a suitable plastic.

The first fasteners 37 are along the edge 43 arranged, the entrance opening 29 surrounds. In this case, a plurality of first fastening elements 37 be provided or a single, along the inlet opening 29 closed circumferential first fastener 37 ,

The housing 2 the assembly of the invention 39 has a complex structure with a high degree of integration. The housing 2 is suitably produced as a cast component with a lost shape (Lostform method), it being expedient to use light metal alloys, for example aluminum or magnesium alloys. The section 18 the fresh gas system 19 can consist of a suitable plastic or of sheet metal.

The module according to the invention 39 works as follows:
The EGR valve 4 sets the desired EGR recirculation rate so that more or less exhaust gases through the exhaust inlet 7 in the channel system of the housing 2 entry. The exhaust gases pass over the first branch 8th the inlet pipe 9 to the second connection area 6 in which the EGR valve 4 sets the respective EGR rate. The second branch 10 the inlet line 9 leads the exhaust gases to the bypass valve 3 , In normal operation, the bypass valve is switched so that only the distribution channel 11 supplied with the exhaust gases. Accordingly, the exhaust gases flow through the distribution channel 11 putting the exhaust flow parallel to the cooling channels 31 divides. In the cooling channels 31 the exhaust gases are cooled and can then enter the inlet 29 of the section 18 enter. In a warm-up operation or a Zuheizbetrieb is the bypass valve 3 switched so that the exhaust gases exclusively into the bypass distribution channel 12 be initiated. The exhaust gas flow is then from the bypass manifold 12 parallel to the bypass channels 33 distributed, whereby the exhaust gas flow is substantially uncooled through the inlet opening 29 in the section 18 the fresh gas system 19 arrives.

Claims (15)

Fresh gas leading section of a fresh gas system ( 19 ) for an internal combustion engine, in particular in a motor vehicle, - with a lateral inlet opening ( 29 ) for recirculated exhaust gas of an exhaust gas recirculation device of the internal combustion engine, - with at the section ( 18 ) formed first fasteners ( 37 ) used to set the section ( 18 ) on a housing ( 2 ) of an exhaust gas cooler ( 1 ) of the EGR device with second fastening elements ( 38 ) interacting with the housing ( 2 ) are formed, - wherein the housing ( 2 ) a distribution channel ( 11 ), the input side with an exhaust gas inlet ( 7 ) of the housing ( 2 ) can be connected communicatively for uncooled, recirculated exhaust gases and the output side with a plurality of cooling channels ( 31 ) communicating with the inlet ( 29 ) of the section ( 18 ), the housing ( 2 ) a coolant channel system ( 13 ) containing the cooling channels ( 31 ) is heat-transmitting coupled and can be flowed through by a coolant. Section according to claim 1, characterized in that - the housing ( 2 ) a bypass distribution channel ( 12 ), the input side with the exhaust gas inlet ( 7 ) is communicatively connectable and the output side with multiple bypass channels ( 33 ) communicates, the output side in the inlet opening ( 29 ) of the section ( 18 ), - that the cooling channels ( 31 ) the bypass channels ( 33 ) and the coolant channel system ( 13 ) are arranged or matched to each other so that exhaust gases passing through the cooling channels ( 31 ) in the section ( 18 ) are more strongly cooled than exhaust gases passing through the bypass channels ( 33 ) in the section ( 18 ). Section according to claim 2, characterized in that in the housing ( 2 ) a connection area ( 5 ) for a bypass valve ( 3 ) is integrated by the distribution channel ( 11 ) and the bypass distribution channel ( 12 ) and to the one with the exhaust inlet ( 7 ) communicably connectable inlet channel ( 9 ) leads. Section according to claim 3, characterized in that the coolant channel system ( 13 ) with the bypass valve connection area ( 5 ) is coupled heat-transmitting. Section according to one of claims 1 to 4, characterized in that in the housing ( 2 ) a connection area ( 6 ) for an exhaust gas recirculation valve ( 4 ), to which one with the exhaust gas inlet ( 7 ) communicating first branch ( 8th ) an inlet line ( 9 ) and from the one with the distribution channel ( 11 ) communicatively connectable second branch ( 10 ) of the inlet pipe ( 9 ) goes off. Section according to claim 5, characterized in that the coolant channel system ( 13 ) with the EGR valve connection area ( 6 ) is coupled heat-transmitting. Section according to one of claims 1 to 6, characterized in that the cooling channels ( 31 ) each have at least one cooling web ( 91 ), which from a wall ( 42 ) of the respective cooling channel ( 31 ) projects transversely and in the respective cooling channel ( 31 ) causes a flow deflection. Section according to one of claims 1 to 7, characterized in that a plurality of cooling webs ( 41 ) are arranged so that in the respective cooling channel ( 31 ) forms a multiple deflection of the exhaust gas flow. Section according to one of claims 1 to 8, characterized in that the cooling channels ( 31 ) at the transition to the inlet opening ( 29 ) each have an outlet cross-sectional area that is greater than a cross-sectional area in the respective cooling channel ( 31 ) or which is greater than a cross-sectional area at the transition from the distribution channel ( 11 ) to the respective cooling channel ( 31 ) or which is larger than a cross-sectional area in the distribution channel ( 11 ). Section according to one of claims 1 to 9, characterized in that the cooling channels ( 31 ) so in the entrance opening ( 29 ) of the section ( 18 ), that a flow direction of the exhaust gases in the inlet opening ( 29 ) substantially transversely to a flow direction of the fresh gases in the section ( 18 ) runs. Section according to one of claims 1 to 10, characterized in that the coolant channel system ( 13 ) is arranged so that it the cooling channels ( 31 ) in total and / or separately laterally. Section according to one of claims 1 to 11, characterized in that the coolant channel system ( 13 ) between the fastening elements ( 37 . 38 ) and the cooling channels ( 31 ). Section according to one of claims 1 to 12, characterized in that - the section ( 18 ) of the fresh gas system ( 19 ) a flange ( 21 ), the at least one continuous insertion opening ( 22 ), that the housing ( 2 ) at least one flange element ( 24 ), one from the housing ( 2 ) facing away from the socket body ( 25 ), a radial from the socket body ( 25 ) projecting contact surface ( 26 ) and a central passage opening ( 27 ), - that the socket body ( 25 ) in the insertion opening ( 22 ) is inserted, - that for fastening the housing ( 2 ) and section ( 18 ) on a carrier component a screw screwed into the carrier component, the passage opening ( 27 ) penetrates and an edge ( 28 ) of the insertion opening ( 22 ) between the carrier component and the contact surface ( 26 ) is arranged. Section according to one of claims 1 to 13, characterized in that the housing ( 2 ) is formed as an integral cast component. Section according to one of claims 1 to 14, characterized in that the section ( 18 ) is designed as a fresh gas distributor, which distributes the supplied fresh gas to a plurality of cylinders of the internal combustion engine.