DE102007048824B4 - Heat exchanger, in particular for exhaust gas cooling - Google Patents

Abstract

Heat exchanger, in particular for exhaust gas cooling, for an internal combustion engine of a motor vehicle having at least a first flow channel (17) for flowing through a first fluid for cooling a second fluid, at least one second flow channel (2) for flowing through the second fluid and at least one third flow channel ( 3) for flowing through the second fluid, wherein the at least one second flow channel (2) and the at least one third flow channel (3) are separated from one another by at least one separating element (4), at least one housing element (5) for the flow of the second flow channel ( 2) and / or the third flow channel (3) with a second fluid, characterized in that at least in sections between the separating element (4) and the at least one housing element (5) at least one channel (6) is designed as a leakage minimization expansion channel (6) in that the leakage flow of second fluid between the at least one the second and the at least one third flow channel (2, 3) minimized and longitudinal and / or transverse strains of the separating element (4) and / or the housing element (5) of the channel (6) are receivable.

Description

The present invention relates to a heat exchanger, in particular for exhaust gas cooling, for an internal combustion engine of a motor vehicle with at least a first flow channel for flow through with a first fluid for cooling a second fluid, with at least one second flow channel for flow through the first fluid and at least one third flow channel to Flow through the first fluid, wherein the at least one second flow channel and the at least one third flow channel are separated by at least one separating element and at least one housing element for flow of the second flow channel and / or the third flow channel with the second fluid.

In internal combustion engines, such as diesel engines, exhaust gas is returned to the engine again to reduce emissions. In this case, a part of the combustion exhaust gas is removed behind the engine and fed back to the unburned air. This recirculated exhaust gas flow is cooled in a heat exchanger such as in an exhaust gas cooler. In this case, the lowest possible mixing temperatures between charge air and the recirculated exhaust gas should be achieved. The low mixing temperatures are required for a fuel-efficient and low-emission combustion process.

For example, during the cold start of the internal combustion engine, the cooling of the recirculated exhaust gas flow is opposed to a desired warming up of the engine. In this case, the exhaust gas is to be mixed substantially uncooled the charge air to accelerate the heating of the engine. In internal combustion engines for passenger cars and / or for commercial vehicles, it is known that in the heat exchanger for exhaust gas cooling at least one path, in particular a bypass channel is provided, in which the exhaust gas is not cooled, but the cooling section is passed around. The exhaust gas is returned to the engine through the cooled and / or uncooled flow channel. For the control or regulation of the exhaust gas flow, a bypass valve or a bypass flap is required for this purpose.

The heat exchanger, in particular for exhaust gas cooling, can be designed, for example, as a U-flow heat exchanger. In this case, the inlet side and the outlet side are substantially identical in the heat exchanger. The exhaust gas in the device is passed substantially longitudinally along the first flow path through the radiator, is then deflected at the end and returned again substantially in the opposite direction to the entry point. The control device, in particular the bypass valve or the bypass flap, is arranged substantially on the inlet side.

Furthermore, a so-called I-flow arrangement of the heat exchanger for exhaust gas cooling is known. In this case, the flow channel for cooling the exhaust gas and the flow channel for the uncooled exhaust gas are arranged substantially parallel to one another. The exhaust gas enters the radiator on one side and exits the radiator on the other side.

The housing element, in which the control device, in particular the bypass flap or the bypass valve, is arranged, and the partition wall between adjacent flow channels have a gap. Due to manufacturing tolerances and to compensate for the thermal expansion of the components, the gap is known from the prior art. However, the gap leads to leaks, so that there is a leakage flow between the channels.

The DE 10 2005 034 363 A1 discloses a heat exchanger according to the preamble of claim 1.

The object of the invention is to eliminate the disadvantages of the prior art, in particular to avoid an overflow of medium from one to the other channel, in particular to reduce at least significantly.

The object of the invention is solved by the features of claim 1.

The heat exchanger for exhaust gas cooling for an internal combustion engine of a motor vehicle has at least in sections between a separating element and a housing element at least one channel which is designed as Leckageminimierungsdehnungskanal such that the leakage current of the second fluid between the at least one second and the at least one third flow channel minimized and longitudinal - And / or transverse expansions of the separating element and / or the housing member are receivable by the channel.

The separating element is in particular a partition wall or a partition wall section.

Under "housing element" is in particular an inlet or outlet diffuser or a flange to understand.

In an advantageous development, second flow channels and / or at least one third flow channel are formed as tubes, which are accommodated in at least one tubesheet.

In an advantageous development of the invention, at least one housing element has at least one first partition wall section.

In a further advantageous development of the invention, the at least one first partition wall section has a first, in particular groove-shaped recess.

In an advantageous development of the invention, at least one second partition wall section is provided.

In a further advantageous embodiment, the first partition wall section and the second partition wall section engage in each other at least in sections.

In this way, a leakage flow between the second flow channels and at least one third flow channel is particularly advantageously minimized.

In an advantageous development of the invention, the second partition wall section has a second, in particular groove-shaped, recess.

In an advantageous development of the invention, the at least one first partition wall section and / or the at least one second partition wall section are formed substantially s-shaped.

In an advantageous embodiment of the invention, the second partition wall portion is integrally connected to the separating element.

In an advantageous embodiment of the invention, the separating element is at least partially formed as a second partition wall section.

In an advantageous development of the invention, the at least one third flow channel is designed as a bypass channel for avoiding the heat exchange between the second medium and the first medium.

In this way, it is particularly advantageous for second medium, for example exhaust gas, to flow uncooled through the heat exchanger.

In an advantageous development, it is provided that at least one control element for bypass and / or exhaust gas recirculation control is arranged adjacent, in particular on the upstream side, of the first partition wall section. In this way, exhaust gas can be cooled by the heat exchanger and / or flow uncooled.

In an advantageous embodiment of the invention, the heat exchanger is designed as an I-flow heat exchanger. It is in a particularly advantageous manner on the one hand, the entry into the heat exchanger and on the other substantially opposite side of the outlet of the heat exchanger.

In another embodiment of the invention, the heat exchanger is designed as a U-flow heat exchanger. In this way, a bottom can be saved particularly advantageously and the inlet and the outlet can be arranged in the heat exchanger on the same side.

Further advantageous embodiments of the invention will become apparent from the dependent claims and from the drawing. The subject matters of the dependent claims relate to the heat exchanger according to the invention, in particular for exhaust gas cooling for an internal combustion engine.

Embodiments of the invention are illustrated in the drawings and will be explained in more detail below, with a limitation of the invention is not intended to take place. Show it

1a : an exhaust gas heat exchanger in the I-flow with a channel, which is designed as a leakage minimization expansion channel;

1b an exhaust gas heat exchanger in the U-flow with a leakage minimization expansion duct;

2a : a section of the exhaust gas heat exchanger of 1a or 1b ;

2 B : an enlargement of the section of the 2a showing the thermal expansion of the second partition wall section;

3 a second embodiment of the leakage minimization expansion channel;

4 A third embodiment of the leakage minimization expansion channel.

1a shows an exhaust gas heat exchanger 1 in the I-flow with a leakage minimization dilatation channel 6 ,

The heat exchanger 1 is hereinafter referred to as exhaust gas heat exchanger 1 designated. Furthermore, in other embodiments, the heat exchanger may be used 1 to act a coolant radiator for engine cooling and / or a charge air cooler for charge air cooling and / or an oil cooler for oil cooling such as transmission oil cooling and / or a condenser of an air conditioner or a gas cooler of an air conditioner or a battery cooler for cooling batteries.

The exhaust gas heat exchanger 1 has an unspecified designated housing. The housing has at least one housing wall 13 and two housing elements 5 on. The housing elements 5 are designed, for example, as flange housing elements or entry and / or exit diffusers. The housing element 5 is cooled in another embodiment, not shown.

The exhaust gas heat exchanger 1 also has two tubesheets 11 on that for receiving the first flow channels 17 , especially the pipes 7 and / or the at least one third flow channel 3 , in particular of the pipe 7 , serve. The pipes 7 are with the tube sheets 11 cohesively such as by welding, soldering, gluing, etc. and / or positively connected such as by folding, crimping or crimping.

The tube sheets 11 have openings for receiving the second flow channels 2 and the at least one third flow channel 3 especially the pipes 7 on.

The second flow channels 2 , especially the pipes 7 , have turbulence-generating elements such as winglets or other forms of any shape, directly into the tubes 7 are introduced. In another embodiment, the turbulence-generating elements by means of, for example, turbulence-generating plates in the tubes 7 inserted.

The housing element 5 and / or the tube sheets 11 are made of a material, in particular of a sheet metal material, such as made of stainless steel or cast iron or aluminum or another metal casting. The housing wall 13 is formed for example of a metal such as stainless steel or of another steel or plastic or fiber composite material. Between the second flow channels 2 and the at least one third flow channel 3 is a partition, in particular a partition, with a second partition wall section 9 arranged.

In another embodiment, the exhaust gas heat exchanger 1 at least one diffuser, in particular an inlet and / or outlet diffuser. Furthermore, a housing is provided for receiving the first flow channels 17 , which are each formed between two adjacent disks and / or the at least one third flow channel 3 formed between two adjacent disks. The discs are the at least one diffuser and / or to the housing cohesively such as by welding, soldering, gluing, etc. and / or positively connected, such as by folding, crimping or crimping.

The second flow channels 2 formed between two adjacent disks have turbulence-generating elements, such as turbulence inserts and / or turbulence-generating elements formed, for example, from the disks or other forms of any shape. In another embodiment, the turbulence-generating elements are arranged by means of, for example, turbulence-generating plates between the discs.

The housing element 5 and / or the diffusers are made of a material, in particular of a sheet metal material, such as stainless steel or cast iron, or of aluminum or of another metal casting. The housing wall 13 is formed for example of a metal such as stainless steel or of another steel or plastic or fiber composite material. Between the second flow channels 2 and the at least one third flow channel 3 is a partition, in particular a partition, with a second partition wall section 9 arranged.

The housing element 5 has a first partition wall section 8th on. The first partition wall section 8th has a first recess 21 on, which is formed for example as a groove such as a rectangular groove. In another embodiment, the first recess 21 a substantially triangular or polygonal or trapezoidal and / or at least partially radius or elliptical cross-sectional area.

The second partition wall section 9 is at least partially in the first recess 21 arranged. The width of the first recess 21 is greater than the width of the second partition wall section 9 , In the illustrated embodiment, the second partition wall section 9 essentially parallel to the first recess 21 arranged. In another embodiment, the second partition wall section 9 essentially at an angle of 0 ° to 90 °, in particular from 0 ° to 70 °, in particular from 0 ° to 45 °, in particular from 0 ° to 30 °, in particular from 0 ° to 15 °, in particular from 0 ° to 5 ° arranged. Adjacent to the first partition wall section 8th is a rule element 12 , In particular arranged a bypass valve or a bypass valve. The rule element 12 assumes a first bypass position BS, in which the entire inflowing exhaust gas, which enters into the heat exchanger 15 in the heat exchanger 1 flows in the direction of the bypass direction BR in the third flow channel 3 passed and flows through this. In a second position KS of the control element 12 , which is shown in dashed lines, the exhaust gas flows in the direction KR through the second flow channels 2 , especially the pipes 7 , In this position, the exhaust gas in the pipes 7 cooled. In a further third position, the control element takes 12 a position between the bypass position BS and the radiator position KS. In this position, exhaust gas flows through both the second flow channels 2 as well as through the at least one third flow channel 3 ,

The channel 6 is designed in particular as a labyrinthine sealing and expansion channel. Thus, the thermal expansion of the first separating element 4 and / or the first partition wall section 8th are received by the channel and a leakage flow from the first space section 23 to the second room section 24 or from the second space section 24 to the first room section 23 be minimized. The exhaust gas flows through the bypass channel 10 or the pipes 7 in the direction of the exhaust gas flow direction ASR.

1b shows the exhaust gas heat exchanger 18 in U-Flow with the leakage minimization strain channel 6 , Identical features are provided with the same reference numerals as in the previous figures.

In contrast to 1a rejects the 1b only one tube bottom 11 on. Furthermore, the third flow channels 3 not designed as a bypass channel. The housing element 5 indicates the heat exchanger outlet 16 on. The bypass channel 10 is in the housing element 5 arranged and trained. The exhaust gas flows in the position KS in the second flow channels 2 , flows through this, is in the deflecting element 14 deflected and flows through the third flow channels 3 back to the heat exchanger outlet 16 ,

In another embodiment, only one diffuser is provided, as well as a housing element 5 for receiving the discs. Furthermore, the third flow channels 3 not designed as a bypass channel. The housing element 5 indicates the heat exchanger outlet 16 on. The bypass channel 10 is in the housing element 5 arranged and trained. The exhaust gas flows in the position KS in the second flow channels 2 , which are formed between adjacent disks, flows through these, is in the deflecting element 14 deflected and flows through the third flow channels 3 , which are formed between adjacent disks, back towards the heat exchanger outlet 16 ,

2a shows a section 20 the exhaust gas heat exchanger 1 , Identical features are provided with the same reference numerals. The enlargement of the 2a is in 2 B and shows a deformed due to thermal expansion second partition wall section 19 ,

The first recess 21 takes this thermal expansion or deformation, which can be done as a transverse and / or longitudinal expansion, on.

3 shows a second embodiment of the leakage minimization expansion channel 6 , Here is the separator 4 and in particular the second partition section 9 substantially S-shaped such that the second partition wall section 9 a second recess 22 forms, in which the first partition wall section 8th engages at least in sections. In this way, the leakage minimization stretch channel becomes 6 educated.

4 shows another third embodiment of the leakage minimization expansion channel 6 , Identical features are provided with the same reference numerals as in the previous figures.

Here is the separator 4 the second partition wall section 9 cohesively attached, for example, welded, soldered or glued and / or form-fitting, for example riveted or screwed.

The features of the various embodiments can be combined with each other. The invention can also be used for other than the areas shown.

Claims (15)

Heat exchanger, in particular for exhaust gas cooling, for an internal combustion engine of a motor vehicle having at least one first flow channel ( 17 ) to flow through with a first fluid for cooling a second fluid, at least one second flow channel ( 2 ) for the flow through with the second fluid and at least one third flow channel ( 3 ) to flow through with the second fluid, wherein the at least one second flow channel ( 2 ) and the at least one third flow channel ( 3 ) by at least one separating element ( 4 ) are separated from each other, at least one housing element ( 5 ) to the flow of the second flow channel ( 2 ) and / or the third flow channel ( 3 ) with a second fluid, characterized in that at least in sections between the separating element ( 4 ) and the at least one housing element ( 5 ) at least one channel ( 6 ) as a leakage minimization expansion channel ( 6 ) in such a way that the leakage flow of second fluid between the at least one second and the at least one third flow channel ( 2 . 3 ) and longitudinal and / or transverse strains of the separating element ( 4 ) and / or the housing element ( 5 ) from the channel ( 6 ) are receivable. Heat exchanger according to claim 1, characterized in that second flow channels ( 2 ) and / or at least one third flow channel ( 3 ) are formed between adjacent disks. Heat exchanger according to claim 1, characterized in that second flow channels ( 2 ) and / or at least one third flow channel ( 3 ) as pipes ( 7 ) are formed in at least one tubesheet ( 11 ) are included. Heat exchanger according to one of the preceding claims, characterized in that the at least one housing element ( 5 ) at least a first partition wall section ( 8th ) having. Heat exchanger according to claim 4, characterized in that the at least one first partition wall section ( 8th ) a first, in particular groove-shaped, recess ( 21 ) having. Heat exchanger according to one of the preceding claims, characterized in that at least one second partition wall section ( 9 ) is provided. Heat exchanger according to claim 6, characterized in that the first partition wall section ( 8th ) and the second partition wall section ( 9 ) mesh at least in sections. Heat exchanger according to claim 6 or 7, characterized in that the second partition wall section (FIG. 9 ) a second, in particular groove-shaped, recess ( 22 ) having. Heat exchanger according to one of claims 6 to 8, characterized in that the at least one first partition wall section ( 8th ) and / or the at least one second partition wall section (FIG. 9 ) are formed substantially S-shaped. Heat exchanger according to one of claims 6 to 9, characterized in that the second partition wall section ( 9 ) cohesively with the separating element ( 4 ) connected is. Heat exchanger according to one of claims 6 to 10, characterized in that the separating element ( 4 ) at least in sections as a second partition wall section ( 9 ) is trained. Heat exchanger according to one of the preceding claims, characterized in that the at least one third flow channel ( 3 ) as a bypass channel ( 10 ) is designed to avoid the heat exchange between the second medium and the first medium. Heat exchanger according to one of claims 4 to 12, characterized in that adjacent, in particular upstream side or downstream, of the first partition wall section ( 8th ) at least one control element ( 12 ) is arranged for bypass and / or exhaust gas recirculation control. Heat exchanger according to one of the preceding claims, characterized in that the heat exchanger ( 1 ) is designed as an I-flow heat exchanger. Heat exchanger according to one of claims 1 to 13, characterized in that the heat exchanger ( 18 ) is designed as a U-flow heat exchanger.

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