DE102014222158A1 - Exhaust gas heat exchanger - Google Patents

Abstract

The invention relates to an exhaust gas heat exchanger (1, 51, 101, 151) having a housing (3) with first tubes (6) arranged therein, wherein the first tubes (6) can be flowed through by a first fluid (9) and by a second fluid (11) are flow around, wherein the first tubes (6) are open at the end for inflow of the first fluid (9) into the first tubes (6) or to the outflow of the first fluid (9) from the first tubes (6) the housing (3) has an inlet port (13) for inflowing the second fluid (11) and an outlet port (14) for discharging the second fluid (11), wherein in the housing (3) a bypass channel (17) is arranged the bypass passage (17) is substantially separated from the fluid flow of the second fluid (11) by a partition member (22, 72, 122, 162).

Description

Technical area

The invention relates to an exhaust gas heat exchanger, in particular for the exhaust gas line of a motor vehicle, in particular according to the preamble of claim 1.

State of the art

By the DE 101 42 539 A1 An exhaust gas heat exchanger has become known which serves to transfer heat between the exhaust gas of an internal combustion engine and a coolant. In this case, the exhaust gas heat exchanger on a housing with an exhaust gas inlet opening and a housing with an exhaust gas outlet, wherein in the housing, a heat transfer area is provided, in which the heat transfer between the exhaust gas and the coolant is made. In the housing, a bypass channel is further provided, through which an exhaust gas flow can be flowed through, in which the heat transfer area is bypassed and no heat transfer takes place, so that in particular in the cold start region, the hot exhaust gas can be supplied to the engine again uncooled. The bypass channel is formed as a double tube with two tubes arranged inside each other, between which an air gap is arranged, which acts thermally insulating. The two tubes of the double tube are connected at one end side with a fixed bearing and have on the other end side on a movable bearing.

The DE 10 2008 014 170 A1 discloses an exhaust gas heat exchanger with a bypass channel, which consists of a double tube with a space between the tubes, wherein for thermal insulation, a knit fabric is provided between the tubes. Alternatively, the DE 10 2008 014 170 A1 as a bypass a single tube, which is covered with the fabric.

Through the knitted fabric or through the intended air gap of the double tube, the bypass channel is thermally insulated. This allows the hot exhaust gas to bypass the heat transfer area during the cold start process and thus to more quickly warm the engine and downstream oxidation catalysts to operating temperature. Accordingly, the nitrogen oxide emission can already be reduced during the cold start and the specific fuel consumption can be reduced by the faster heating of the engine.

In the prior art, at least two components are therefore necessary for the thermal insulation of the bypass channel, ie a pipe and the fabric or two pipes in the double pipe construction. The design with a single tube and the fabric works only in an application as a bypass tube outside of the heat exchanger, in which the bypass pipe is guided in parallel but outside the housing of the heat exchanger. If the bypass pipe insulated with the knitted fabric were to be inserted into the housing of the heat exchanger, and thus coolant would flow around the knitted fabric, the knitted fabric would lose its insulating effect.

In the formation of the bypass as a double tube has been found in practice that the connection between the inner tube and the outer tube is a weak point. The two tubes are due to the thermal insulation at different temperatures. Due to the occurring temperatures of the two tubes, wherein the inner tube is relatively hot due to the exhaust gas flow and the outer tube remains relatively cool due to the coolant flow in comparison and occurring due to the vibrations occurring during operation of the motor vehicle, it can lead to failure of the bypass tube and thus the Abgaswärmeübertragers ,

Presentation of the invention, object, solution, advantages

It is the object of the invention to provide an exhaust gas heat exchanger which is simple in construction and yet has a durable construction of a bypass tube, which is improved over the prior art.

This object is achieved with the features of claim 1.

An embodiment of the invention relates to an exhaust gas heat exchanger with a housing having disposed therein first tubes, wherein the first tubes are flowed through by a first fluid and a second fluid flow around, the first tubes are open end formed for inflow of the first fluid into the first Tubes and the outflow of the first fluid from the first tubes, wherein the housing has an inlet port for flowing in the second fluid and an outlet port for the outflow of the second fluid, wherein in the housing, a bypass passage is arranged, wherein the bypass passage of the fluid flow of the second fluid is arranged separated by a separating element substantially. Due to the arrangement of the separating element in the housing, the bypass channel is at least substantially separated or obstructed or completely separated from the flow of the second fluid so that there is virtually no or no heat transfer and thus virtually no or no cooling of the first fluid flowing through the bypass channel.

The first fluid is in particular exhaust gas or an exhaust gas-air mixture, such as an exhaust-charge air mixture. The second fluid is in particular a liquid coolant, such as water or a water-glycol mixture, etc.

According to the invention, it is advantageous if the first tubes are formed with two end-side ends and the first tubes are each sealed at the ends in openings of a respective tube plate and the respective tubesheet is connected to the housing. As a result, the tubes are securely and fluid-tightly received and spaced from each other. The second fluid may flow around the spaced-apart tubes and the sealed connection with the tubesheets at both ends of the tubes provides for media separation.

Furthermore, it is advantageous if the separating element is arranged between the first tubes and the bypass channel. As a result, the volume occupied by the bypass tube can be at least substantially separated or obstructed by the fluid flow of the second fluid.

It is also advantageous in a further embodiment, when the separating element is sealingly received in the housing of the bypass channel. Thus, the separating element can be arranged sealingly both on the housing and, for example, on the tube plates, so that no fluid flow of the second fluid can flow around the bypass tube, which also flows around the first tubes.

It is also advantageous if the separating element is sealingly received in the housing of the bypass channel, wherein the separating element bears sealingly against the tube sheets and / or on the housing. Thus, in the presence of the tubesheets, sealing of the separating element in the housing is achieved and the second fluid can not flow or flow around the bypass tube. A sealed arrangement can also be achieved, for example, by pouring or soldering or welding. Alternatively, a tight arrangement can be achieved in particular in plastic housings by gluing.

It is also advantageous if the separating element is not received sealingly in the housing, wherein the separating element is not arranged sealingly to at least one of the tube sheets and / or to the housing. As a result, a certain flow of the second fluid past the separating element is still possible, but this hinders the flow past the bypass channel or around the bypass channel and thus reduces the heat transfer. However, this makes it possible to arrange and fasten the separator rather uncomplicated, which facilitates the production.

It is particularly advantageous if the bypass channel is formed by at least one second tube, which is arranged in the housing. Thereby, the fluid flow through the bypass passage is distributed to the at least one second tube or a plurality of second tubes, which can be easily installed together with the first tubes.

It is particularly advantageous if the at least one second tube is formed with two end-side ends, wherein the at least one second tube is received sealed end in each case in an opening of a tube plate. Thus, in the arrangement of two tubesheets, the arrangement can be made according to the arrangement of the first tubes, which simplifies assembly.

It is also advantageous if a plurality of second tubes is provided to form the bypass channel. Thereby, for example, the same type of tube for the first tubes and for the second tubes can be used, wherein a plurality of such tubes are used as second tubes to achieve the intended cross-section of the bypass channel. Alternatively or additionally, a tube or even a plurality of tubes can be used with an enlarged cross section relative to the first tubes.

It is also advantageous if the bypass channel is formed by a cavity, which is formed in the housing. As a result, the bypass channel is integrated directly into the housing and sealed off by the separating element so that the second fluid can not penetrate into the bypass channel. This is advantageous because no separate element is needed to form the bypass channel. The second tubes can be saved. This reduces the costs and installation costs.

It is advantageous if the cavity is bounded by the housing, optionally by the two tube sheets and by the separating element. Thus, a simple construction to achieve the bypass channel can be formed.

Thus, it is also advantageous if, in Providence the tube bottom, the two tube plates each have at least one opening which communicate with the cavity. Thus, the first fluid can flow through the respective opening in the tube plate into the cavity formed as a bypass channel or flow out of this.

It is particularly advantageous if the housing is made of plastic or metal, in particular of cast metal or sheet metal. In the production of the housing of cast metal or made of plastic, the separating element can be advantageous with cast, which avoids a subsequent attachment and sealing. Also, the separator can be inserted into the housing and soldered, welded or glued. For mounting and holding the separating element additional holding means and / or insertion elements may be provided, such as an import and holding etc.

It is also advantageous if a connection flange or diffuser is provided on at least one end region of the housing for introducing the first fluid into the first tubes open at the ends and / or for discharging the first fluid out of the first tubes open at the end.

It is also particularly advantageous if an exhaust valve for controlling the volumetric flow of the first fluid flowing through the exhaust gas heat exchanger and / or a bypass valve for controlling the volumetric flow of the first fluid flowing through the bypass duct is provided on the connection flange or on the diffuser.

Further advantageous embodiments of the invention are described by the following description of the figures.

Brief description of the figures

The invention will be explained in more detail on the basis of at least one embodiment with reference to the figures. Show it:

1 schematically an embodiment of a heat exchanger core of a Abgaswärmeübertragers,

2 schematically another embodiment of a heat exchanger core of a Abgaswärmeübertragers,

3 schematically another embodiment of a heat exchanger core of a Abgaswärmeübertragers,

4 a further embodiment of a heat exchanger core of a Abgaswärmeübertragers, and

5 a schematic embodiment of an exhaust gas heat exchanger with a heat transfer core according to 3 ,

Preferred embodiment of the invention

The 1 shows a heat transfer core 2 an exhaust gas heat exchanger 1 , where appropriate, to the heat transfer core 2 attached diffusers and / or connection elements, such as connection flanges, are not shown. These are exemplary in the 5 shown.

The heat transfer core 2 according to 2 has a housing 3 on, which tubular with two open end faces 4 . 5 is trained. In the housing are first tubes 6 arranged, which are spaced from each other and which end open ends 7 . 8th exhibit. The open ended ends 7 . 8th serve the inflow and outflow of a first fluid 9 in the first tubes 6 , The first pipes 6 serve accordingly as the first fluid channel 10 , The pipes 6 be from a second fluid 11 flows around, leaving the space around the first pipes 6 and the space between the first pipes 6 a second fluid channel 12 form.

The exhaust gas heat exchanger 1 is with his case 3 formed such that the first tubes 6 in the case 3 are arranged and the first pipes 6 from the first fluid 9 can be flowed through and the second fluid 11 can be flowed around, with the first tubes 6 open at the end are formed for the inflow of the first fluid 9 in the first tubes 6 or to the outflow of the first fluid 9 from the first pipes 6 , The first pipes 6 are substantially parallel to each other and parallel to the housing 3 or arranged to the housing longitudinal axis. The first pipes 6 are advantageously arranged in rows and form a heat transfer matrix. Like in the 1 It can be seen on both sides of the housing 3 tube sheets 15 . 16 arranged, with the ends 7 . 8th the first pipes 6 in openings 23 the tube sheets 15 . 16 sealed are included. So can each one of the ends 7 . 8th with the respective tubesheet 15 . 16 be soldered, welded or glued or otherwise sealed tethered.

The first fluid 9 can flow in the direction shown or alternatively vice versa. Also the second fluid 11 flows advantageously in the direction shown. Alternatively, the second fluid 11 also flow in the opposite direction.

The tube sheets 15 . 16 are in turn to the housing 3 sealed, so that the second fluid channel is between the tubesheets 15 . 16 in the case 3 extends and sealed to the outside.

The housing 3 points to the inflow and outflow of the second fluid 11 an inlet port 13 for inflow of the second fluid 11 and an outlet port 14 to the outflow of the second fluid 11 on.

In the case 3 is still a bypass channel 17 arranged. The bypass channel 17 is in the embodiment of 1 as a second tube 18 or alternatively as a plurality of second tubes 18 educated. The second pipe or the second pipes 18 are parallel and spaced from the first tubes 6 arranged. The at least one second tube 18 again has two end ends 19 . 20 on, wherein the respective second tube 18 with his ends 19 . 20 in each case an opening 21 one of the tube sheets 15 . 16 sealed is received.

About an unillustrated bypass valve, which may be formed for example as a bypass valve, the influx to the first tubes 6 as the first fluid channel or to the bypass channel 17 or the at least one second tube 18 be controlled so that either the first fluid in the first tubes 6 is cooled or is not or not substantially cooled in the bypass channel.

This is the bypass channel 17 from the fluid flow of the second fluid 11 by a separating element arranged in the housing 22 arranged substantially separately. The separating element 22 is designed as a partition, which is parallel to the bypass channel in the housing 17 extends and the space around the bypass channel 17 from the space around the first pipes 6 separates. This ensures that the second fluid does not bypass the bypass channel 17 or can flow along the bypass channel. For this purpose, the separating element on the tube sheets 15 . 16 and attached to the housing sealed, so that a sealed space area is formed, in which the bypass channel 17 is arranged.

The bypass channel 17 can be used as a single tube 18 as a bypass tube in the housing 3 of the heat exchanger 1 be integrated. Alternatively, a plurality of individual tubes in the housing 3 be integrated, which together form the bypass channel. The thus arranged second tube 18 is with the tube sheets 15 . 16 together. So that the second tube 18 depending on the design of the heat exchanger 1 does not come into contact with the coolant formed as a second fluid, the separating element 22 in the case 3 arranged. The separating element 22 provides a seal to the tubesheet 15 . 16 for that the bypass channel 17 does not come into contact with the second fluid. This creates an air gap between the housing 3 and the bypass channel 17 which is the bypass channel 17 thermally insulated.

The 2 shows a further embodiment of a heat transfer core 52 another heat exchanger 51 , such as an exhaust gas cooler. The heat transfer core 52 of the 2 corresponds essentially to the heat transfer core of the 1 , Accordingly, the same reference numerals are used for the same parts and not described parts of the 2 will be on the description of 1 explicitly referenced.

In the embodiment of 2 is the separator 72 different from the separator 22 of the 1 educated. The separating element 72 is not sealed in the housing 3 arranged and allows a flow of the second fluid 11 at the bypass channel 17 along or around it. The separating element 72 is designed as a partition, but not in the longitudinal direction, the full inner length of the heat exchanger core or the first tubes 6 and the at least one second tube 18 having. This can be done in the fields 80 the second fluid in the region of the second tube 18 stream. However, the flow of the second fluid is severely limited, so that no significant heat transfer and no substantial cooling of the first fluid takes place. The areas 80 lie on both end regions of the separating element 72 in front.

The 3 shows a further embodiment of a heat transfer core 102 another heat exchanger 101 , such as an exhaust gas cooler. The heat transfer core 102 of the 3 corresponds essentially to the heat transfer core of the 1 , Accordingly, the same reference numerals are used for the same parts and not described parts of the 3 will be on the description of 1 explicitly referenced.

In the embodiment of 3 is the separator 122 different from the separator 22 of the 1 educated. The separating element 122 is not sealed as a bridge in the housing 3 arranged and the web allows a flow of the second fluid 11 at the bypass channel 17 along or around it. The separating element 122 is designed as a rather narrow web, which in its longitudinal direction is not the full inner length of the heat exchanger core or the first tubes 6 and the at least one second tube 18 having. This can be done in the fields 110 the second fluid in the region of the second tube 18 stream. However, the flow of the second fluid is again severely limited, so that no significant heat transfer and no substantial cooling of the first fluid takes place. The areas 110 lie on both end regions of the separating element 122 in front.

In the embodiments of the 1 to 3 is a partition or a separating web as a separating element 22 . 72 . 122 in the case 3 of the heat exchanger 1 integrated. The bypass channel 17 is through at least a second tube 18 educated. The separating element 22 ensures its sealing to the respective tubesheet 15 . 16 and optionally to the housing 3 for that the bypass channel 17 not with the second fluid designed as a coolant 11 comes into contact. This creates an air gap between the housing 3 and bypass channel 17 which is the bypass channel 17 thermally insulated. Will the separator 72 . 122 as a divider to the tube sheet 15 . 16 not sealed, it is designed so that the flow of the second fluid 11 in the area of the bypass channel 17 is severely restricted if a rather small gap between the web and tubesheet 15 . 16 remains. Thus, the thermal insulation is carried out by the significantly limited flow around the bypass channel 17 with the second fluid designed as a coolant 11 ,

The 4 shows a further embodiment of a heat transfer core 152 another heat exchanger 151 , such as an exhaust gas cooler. The heat transfer core 152 of the 4 corresponds essentially to the heat transfer core of the 1 , Accordingly, the same reference numerals are used for the same parts and not described parts of the 4 will be on the description of 1 explicitly referenced.

In the embodiment of 4 is the separator 162 equal to the separator 22 of the 1 educated. The separating element 162 is sealed as a partition plate in the housing 3 arranged. In contrast to the embodiment of 1 is in the embodiment of 4 the bypass channel 167 formed without a second tube. The bypass channel 167 is doing from the wall 168 of the housing 3 and of the separator 162 formed, wherein the separating element 162 Adjacent to the respective tubesheets at its two lateral end regions and sealingly abuts there.

The separating element, which is designed as a partition wall or as a separating web, is in the housing 3 use. In this case, the housing may advantageously be made of metal or plastic. In a die-cast aluminum housing or in a plastic housing, it is particularly advantageous if the separating element 22 is integrated into the mold during the manufacturing process, and thus no additional component is required or no additional component is to be used during assembly. In this case, the separating element can be produced during the casting process or during the injection molding process for the production of plastic parts. Alternatively, the separating element can also be produced and poured or injected as an insert.

In a case 3 made of steel, the function of the separating element can be taken over by a separating plate, which can optionally also serve as a coolant guide plate.

The 5 shows a representation of a heat exchanger 101 with a heat transfer core 102 according to 3 , It is the heat transfer core 102 on the left in 5 a connection flange 201 attached, in which the exhaust gas as a first fluid in a channel 202 can flow in. The channel 202 is with a switch 203 trained, so he on the subchannels 205 and 206 is divided. A trained as a bypass valve bypass valve 204 is intended to be due to its position the channel 202 with the subchannel 205 and / or with the subchannel 206 connect to. This allows the first fluid either through the first tubes 6 with cooling or through the bypass channel without or without substantial cooling.

Furthermore, to the heat transfer core 102 on the right in 5 a connection flange 210 attached, through which the cooled or uncooled exhaust gas can flow to from a designated exhaust valve 211 to be regulated in its quantity.

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 10142539 A1 [0002]
• DE 102008014170 A1 [0003, 0003]

Claims (15)

Exhaust gas heat exchanger ( 1 . 51 . 101 . 151 ) with a housing ( 3 ) with first tubes ( 6 ), the first tubes ( 6 ) of a first fluid ( 9 ) are flowed through and by a second fluid ( 11 ) are flowed around, wherein the first tubes ( 6 ) are open at the ends for inflow of the first fluid ( 9 ) in the first tubes ( 6 ) or to the outflow of the first fluid ( 9 ) from the first tubes ( 6 ), the housing ( 3 ) an inlet port ( 13 ) for the inflow of the second fluid ( 11 ) and an outlet port ( 14 ) for the outflow of the second fluid ( 11 ), wherein in the housing ( 3 ) a bypass channel ( 17 ), characterized in that the bypass channel ( 17 ) of the fluid flow of the second fluid ( 11 ) by a separating element ( 22 . 72 . 122 . 162 ) is arranged substantially separately. Exhaust heat exchanger according to claim 1, characterized in that the first tubes ( 6 ) with two ends ( 7 . 8th ) and the first tubes ( 6 ) at each end in openings ( 23 ) of a respective tube plate ( 15 . 16 ) are received sealed and the respective tube sheet ( 15 . 16 ) with the housing ( 3 ) connected is. Exhaust heat exchanger according to claim 1 or 2, characterized in that the separating element ( 22 . 72 . 122 . 162 ) between the first tubes ( 6 ) and the bypass channel ( 17 ) is arranged. Exhaust heat exchanger according to claim 3, characterized in that the separating element ( 22 . 162 ) in the housing ( 3 ) the bypass channel ( 17 ) is sealingly received. Exhaust heat exchanger according to claim 3, characterized in that the separating element ( 22 . 162 ) in the housing ( 3 ) the bypass channel ( 17 ) is received sealingly, wherein the separating element ( 22 . 162 ) at the tube sheets ( 15 . 16 ) and / or on the housing ( 3 ) sealingly abuts. Exhaust heat exchanger according to claim 3, characterized in that the separating element ( 72 . 122 ) in the housing ( 3 ) is not received sealingly, wherein the separating element ( 72 . 122 ) to at least one of the tubesheets ( 15 . 16 ) and / or to the housing ( 3 ) is not arranged sealingly. Exhaust heat exchanger according to one of the preceding claims, characterized in that the bypass channel ( 17 ) by at least one second tube ( 18 ) is formed, which in the housing ( 3 ) is arranged. Exhaust heat exchanger according to claim 7, characterized in that the at least one second tube ( 18 ) with two ends ( 19 . 20 ), wherein the at least one second tube ( 18 ) end in one opening ( 21 ) of a tube plate ( 15 . 16 ) is sealed. Exhaust heat exchanger according to one of claims 7 or 8, characterized in that a plurality of second tubes ( 18 ) to form the bypass channel ( 17 ) is provided. Exhaust heat exchanger according to one of the preceding claims 1 to 6, characterized in that the bypass channel ( 17 ) is formed by a cavity which in the housing ( 3 ) is trained. Exhaust heat exchanger according to claim 10, characterized in that the cavity of the housing ( 3 ), optionally from the two tubesheet ( 15 . 16 ) and of the separating element ( 162 ) is limited. Exhaust heat exchanger according to claim 11, characterized in that the two tube sheets ( 15 . 16 ) each at least one opening ( 21 ) which communicate with the cavity. Exhaust heat exchanger according to one of the preceding claims; characterized in that the housing ( 3 ) made of plastic or metal, in particular of cast metal or sheet metal is formed. Exhaust heat exchanger according to one of the preceding claims, characterized in that on at least one end region of the housing ( 3 ) a connection flange ( 201 . 210 ) or diffuser is provided for introducing the first fluid ( 9 ) in the end open formed first tubes ( 6 ) or for discharging the first fluid ( 9 ) from the end open formed first tubes ( 6 ). Exhaust heat exchanger according to one of the preceding claims, characterized in that on the connecting flange ( 201 . 210 ) or at the diffuser an exhaust valve ( 211 ) for controlling the volume flow of the first fluid flowing through the exhaust gas heat exchanger ( 9 ) and / or a bypass valve ( 204 ) for controlling the through the bypass channel ( 17 ) flowing volume flow of the first fluid ( 9 ) is provided.

Images