JP5395783B2 - Heat exchanger with tube bundle - Google Patents

Description

  The present invention relates to a heat exchanger, and more particularly to an exhaust gas heat exchanger having a bundle of tubes.

  The aforementioned type of heat exchanger is particularly useful for cooling the exhaust gas of internal combustion engines. First of all, cooling is performed for the purpose of adding cooled exhaust gas to the outside air supplied to the combustion process so that the oxygen content is reduced. Another purpose of the heat exchanger is to utilize the thermal energy inherent in the exhaust gas. Furthermore, the heat exchanger is also used on the intake side of an engine with a supercharger, a fuel cell or other cases. There is a need to minimize the structural volume for use in vehicles with an internal combustion engine, which is the most important area of application of heat exchangers with tube bundles.

  International Patent Application Publication No. 00/00778 discloses a flat tube heat exchanger in which differently oriented flat tubes are formed in a U-shape and are formed as circular cross-section tubes in the U-shaped region. Fins are required between the U-shaped flat tubes to ensure optimal heat transfer to the surrounding media.

  This solution is disadvantageous in that fins are essential and as a result, the heat exchanger requires more technical effort and more space.

  German Offenlegungsschrift 10 2008001660 describes a lightweight flow heat exchanger in which an independently disposed exchanger tube for conducting exhaust gases is installed in a separately disposed closed casing. To do. The casing is passed by coolant flowing around the outside of the exchanger tube. Both ends of the exchanger tube are penetrated in a gas-tight and liquid-tight manner through a casing cover that seals the jacket portion. Thereby, the inlet and outlet of the exchanger tube are positioned outside the casing. The exchanger tube is designed as a circular cross-section tube with different configurations that increase the surface and break the flow.

  The disadvantage of this solution is that the heat exchanger area is small, thereby reducing the heat exchanger capacity with respect to the structural volume of the heat exchanger. Furthermore, circular cross-section tubes have limited heat dissipation characteristics.

  German Offenlegungsschrift 19756961 describes an arrangement of heat exchangers having one row next to each other and tubes arranged in parallel and at least two rows behind each other. The tube is connected in heat transfer with a cooling member designed as a cooling fin. Each two tubes form the legs of a tube fork made as one piece, connected in communication with each other through curved pieces. The tube is formed as a flat tube and has two flat long side surfaces arranged parallel to each other and two short side surfaces connected to the long side surface. The cooling fin extends at least between adjacent flat tubes, and the cooling fin is attached to the long side surface of the fin in a heat transfer manner.

  The arrangement is disadvantageous because of the expensive use of cooling fins, and this arrangement is not suitable for liquid coolant flowing around the outer surface of the tube,

  Another disadvantage and deficiency in the prior art is the large required space required for heat exchangers, which can be a problem especially in automobiles where only limited space can be made available for components. To solve this problem, the prior art suggests the use of fins that can help to increase the heat exchanger area. However, the ratio of volume reduction to the additional cost resulting from the manufacture of heat exchanger tubes covered with fins is relatively small.

  Tube bundles of tubes with a circular cross-section result in a smaller package density, or a larger gap between the circular cross-sections compared to other cross-sectional geometries such as triangle, square or flat tube cross-sections, respectively. To occur. Furthermore, the gap between the circular cross-sections is not very accessible with the medium flowing around the circular cross-section because the cross-sectional area at the entrance to the gap cross-sectional area is correspondingly narrow compared to the gap cross-sectional area. For the other cross sections mentioned above, the ratio between the inlet and the gap cross sectional area is balanced.

  According to the prior art, U-shaped passages are often obtained using straight pipes and turning shapes (scoops). Thus, although no heat transfer takes place in the direction change zone, additional pressure losses occur due to one additional outflow and inflow process respectively in the direction change zone. This disadvantage can already be overcome by using a circular section tube bent into a U-shape. However, there remains the disadvantage of low heat exchanger capacity due to the maximized ratio of the circular cross-sectional area to the outer periphery of the circular cross-section and the minimum heat exchanger area resulting therefrom.

International Patent Application Publication No. 00/00778 German Patent Application Publication No. 102008001660 German Patent Application Publication No. 19756961

  Accordingly, the present invention further provides a heat exchanger having a tube bundle that allows the structural volume of the heat exchanger to be minimized without any fins and without any loss in heat exchanger capacity while reducing pressure loss. The purpose is to develop and solve problems.

This problem is solved by a heat exchanger having independently formed heat exchanger tubes. The heat exchanger tube is placed in a separately formed and closed casing, and the coolant flows around the outer surface of the heat exchanger tube.
The casing includes at least a casing cover and a jacket portion, the jacket portion is sealed by the casing cover, and both ends of the exchanger tube are arranged so that the inlet and the outlet of the exchanger tube are disposed outside the casing. Airtight and liquid-tightly penetrate through the casing cover.

  Furthermore, part of this solution is a tube bundle with a U-shaped bending area and a straight tube end. The tube bundle is a flat tube at least in the region of the straight tube end. The flat tube has two flat long side surfaces arranged in parallel to each other and two short side surfaces connected to the long side surface, and this cross section has two long sides, one of which is opposite to the other. A rectangle having a side and two short sides. The other flat tube has a cross section with two long sides connected by partial circular elements.

  The advantage of said solution is in particular to have a flat tube with a tube cross-section that allows a high heat exchanger capacity, obtained as a large surface area compared to a small cross-sectional area.

  Furthermore, the problem of the present invention is solved by the fact that the U-shaped bent region has a cross-sectional shape different from the flat cross section of the straight pipe end.

  Further, according to the present invention, the straight tube ends of the flat tubes face each other with their narrow side surfaces in the heat exchanger. In a modified embodiment of the present invention, the straight tube ends of the flat tubes face each other with their wide side surfaces. This is because if the entire tube, including the U-shaped bend region, is made of a flat tube, in some alternative embodiments the tube is bent into a narrow side plane, and in other alternative embodiments the tube is bent into a wide side plane. Means.

The merit of bending to the narrow side plane is that the U-shape can be easily obtained because the section modulus is technically smaller in the narrow side plane direction.
If bending is performed on the wide side plane, the section modulus is high. In addition to bending to the wide side plane of the cross section of the flat tube, a flat geometric shape in the turning region can be made by alternative methods. However, this solution is advantageous in that the wide side surface of the flat tube extends in the flow direction of the coolant circulating in the casing of the heat exchanger. Thereby, suitable heat transfer is possible.

  In a further advantageous embodiment of the invention, the tube cross-section of the U-shaped bend region has a circular cross-sectional shape. In an advantageous embodiment of the invention, the tube cross-section of the U-shaped bend region has a rectangular or elliptical cross-sectional shape.

  First, the use of a circular cross section is a technical advantage that bending a flat tube can be particularly problematic when performed on the wide side plane of the contour, so that bending is no longer necessary . Furthermore, the optimum flow state can be recognized by the circular cross section in the U-shaped bend region. This is especially important if the bend is formed using a flat tube and it cannot be guaranteed that the bend will not lead to a narrow cross section.

  In a particularly advantageous embodiment, the tubes of the tube bundle comprise a structured surface. This structure of the preferred embodiment consists of square recesses on the outside of the tube that are spaced apart from one another so that the spacing is approximately twice the length of the square sides. In a variant embodiment for this purpose according to the invention, this structure consists of an annular or helical groove formed in the tube wall.

  The formation of the structure on the tube wall leads to advantageous flow turbulence inside the tube and leads to laminar flow and boundary layer failure. This results in improved heat transfer between the medium flowing in the tube and the tube wall, resulting in increased heat exchanger capacity.

  Furthermore, it is useful to combine a plurality of U-shaped tubes together in a tube bundle. Here, at least two U-shaped tubes having U-shaped bends of equal radius and straight flat tube ends of equal length are positioned side by side, and at least two U-shaped tubes, each having a different radius, are located within each other. It is an advantage when it is positioned at.

  U-tubes that are advantageously combined with each other create large areas of active heat transfer in small spaces. Thereby, the heat exchanger achieves a high capacity while requiring only a small structural space.

  It has been shown to be particularly useful to arrange the bending regions of the heat exchanger tubes of the tube bundle alternately offset from one another. By skillfully arranging alternating offsets, a high package density can be obtained despite the transition to a circular geometry in the turning region.

  According to a preferred embodiment of the invention, the heat exchanger is designed such that the heat exchanger is used in an automobile exhaust gas string. To that end, the casing cover forms an interface for connecting the heat exchanger to the automobile exhaust gas system.

  The advantages of the heat exchanger according to the invention are particularly advantageous in motor vehicles where the available installation space is limited. Thus, heat exchangers optimized in such a manner that provide high capacity heat transfer while requiring less space are very well suited for use in automobiles.

  It is useful when the heat exchanger comprises a plurality of heat exchanger tubes positioned within the casing that fluidly redirect to form a switched tube bundle in parallel.

  Due to the parallel connection of the heat exchanger tubes, a higher proportion of exhaust gas can pass through the heat exchanger extracting heat from the exhaust gas.

  In an advantageous embodiment of the invention, the coolant inlet and the coolant outlet are arranged such that the coolant inlet and / or the coolant outlet are positioned in the casing cover.

  By integrating the coolant inlet and the coolant outlet into the casing cover, all interfaces are integrated into one structural member and one location. Thus, the final assembly of the vehicle to which the heat exchanger is mounted, especially for use in a motor vehicle, is improved and simplified. In this way, all interfaces can be integrated into a narrow space and connected to the heat exchanger in one installation step.

  The heat exchanger is shown to be designed so that the heat exchanger can be advantageously used in an automotive coolant cooled charge air cooler. Here, the cooling liquid cools the high temperature compressed outside air coming from the turbocharger.

  Another advantageous field of use of heat exchangers is automotive coolant cooled oil coolers. The heat exchanger is particularly suitable for cooling hot engine oil using a coolant.

  A particularly positive aspect of the present invention is the possibility that the jacket part of the casing is made of a material having a melting point of 1000 ° C. or less. Surprisingly, it is known that materials that can be used for the jacket must only meet the requirements arising from the use of a cooling medium. This is first related to pressure, temperature and chemical resistance. Chemical resistance is particularly important when oil is used as the cooling medium. Thereby, even if the heat exchanger is used as an exhaust gas cooler, a material with a low melting point much lower than 1000 ° C., such as synthetic resin or aluminum, can be used for the jacket part. it can. These materials usually cannot withstand exhaust gas temperatures. This advantage arises from the use of a U-shaped tube for heat transfer and the fact that its shape is a sealed U-shaped bend.

  In addition, there is a favorable possibility that the material of the cooler casing can be chosen very freely, so that light and cheap materials are available which are decisive for the weight and price of the final product.

  In general, the advantages of the present invention are increased heat exchanger capacity in a small structural space, increased freedom in placement of heat exchanger tubes bent into a U-shape, resulting in higher package density. Possible. The heat exchanger according to the present invention is small and lighter. The higher heat transfer efficiency of the heat exchanger saves material compared to prior art heat exchangers having the same capacity.

  Other details, features and advantages of the present invention will become apparent from the following description of exemplary embodiments in conjunction with the accompanying drawings.

The heat exchanger which has the tube bundle which consists of a flat tube by a top view is shown. The heat exchanger which has the tube bundle which consists of a flat tube by a front view is shown. The heat exchanger which has the tube bundle which consists of a flat tube by a side view is shown. The heat exchanger which has a tube bundle which consists of a flat tube by an exploded view is shown. 1 shows a heat exchanger having a tube bundle consisting of flat tubes bent sideways according to a top view. The heat exchanger which has a tube bundle which consists of a flat tube bent sideways by a front view is shown. 1 shows a heat exchanger having a tube bundle consisting of flat tubes bent sideways according to a side view. 1 shows a heat exchanger having a tube bundle consisting of flat tubes bent sideways according to an exploded view. 1 shows a heat exchanger having a tube bundle consisting of a flat tube and a circular cross-section tube according to a top view. 1 shows a heat exchanger having a tube bundle consisting of a flat tube and a circular cross-section tube according to a front view. 1 shows a heat exchanger having a tube bundle consisting of a flat tube and a circular cross-section tube according to a side view. 1 shows a casing and seal of a heat exchanger having a tube bundle consisting of a flat tube and a circular section tube according to a perspective view. The tube bundle and casing cover of a heat exchanger which consist of a flat tube and a circular section pipe by a perspective view are shown. Fig. 2 shows a tube bundle and casing cover of a heat exchanger with flat tubes and circular cross-section tubes according to a side view. The heat exchanger which has the tube bundle which consists of the flat tube arrange | positioned sideways by a front view, and a circular cross-section tube is shown. 1 shows a heat exchanger having a tube bundle consisting of flat tubes and circular cross-section tubes arranged sideways according to a top view. 1 shows a heat exchanger having a tube bundle consisting of flat tubes and circular cross-section tubes arranged sideways according to a side view. 1 shows a tube bundle and casing cover of a heat exchanger having a tube bundle consisting of flat tubes and circular cross-section tubes arranged sideways according to a perspective view. 1 shows a jacket part with a heat exchanger seal having a tube bundle consisting of flat tubes and circular cross-section tubes arranged sideways according to a perspective view. Fig. 3 shows a tube bundle and casing cover of a heat exchanger having a tube bundle consisting of flat tubes and circular cross-section tubes arranged sideways according to a side view. Fig. 2 shows a heat exchanger with a bundle of tubes arranged in an offset arrangement of flat tubes and circular section tubes according to a top view. 1 shows a heat exchanger having a bundle of tubes arranged in an offset arrangement of flat tubes and circular cross-section tubes according to a front view. Fig. 2 shows a heat exchanger with a bundle of tubes arranged in an offset arrangement of flat tubes and circular section tubes according to a side view. Fig. 2 shows a heat exchanger having a tube bundle arranged in an offset arrangement consisting of flat tubes arranged in a lateral direction according to a top view and circular cross-section tubes. Fig. 2 shows a heat exchanger having a bundle of tubes arranged in an offset arrangement consisting of flat tubes arranged in a lateral direction according to a front view and circular cross-section tubes. Fig. 3 shows a heat exchanger having a tube bundle arranged in an offset arrangement consisting of flat tubes arranged in a lateral direction according to a side view and circular cross-section tubes. Fig. 3 shows a heat exchanger having a tube bundle arranged in an offset arrangement consisting of flat tubes arranged in a lateral direction according to a perspective view and circular cross-section tubes. The casing of the heat exchanger according to a perspective view is shown. 1 shows a heat exchanger having a bundle of tubes arranged in an offset arrangement consisting of a flat tube and a circular section tube according to a perspective view. The casing of the heat exchanger according to a perspective view is shown. Fig. 3 shows a heat exchanger having a tube bundle arranged in an offset arrangement consisting of flat tubes arranged in a lateral direction according to a perspective view and circular cross-section tubes. The casing of the heat exchanger according to a perspective view is shown.

FIG. 1 a shows the heat exchanger 1 with a tube bundle 15 consisting of flat tubes according to a top view, in which the narrow side of the flat tubes forming the heat exchanger tubes 6 can be seen. Both the straight tube end 2 and the bent region 3 are formed of flat tubes bent at the narrow side plane in the bent region 3. What is indicated by an arrow is the flow direction of the inflowing gas, and the inlet 12 and the outlet 13 are separately displayed. The inlet 12 and the outlet 13 penetrate the casing cover 4.
A plurality of heat exchanger tubes 6 formed in alignment with each other by bending regions 3 of different radii form a tube bundle 15 together.

  FIG. 1 b shows the heat exchanger 1 with a tube bundle 15 consisting of flat tubes according to a front view and the arrangement of the end 11 of the heat exchanger tube 6 on the casing cover 4. Thereby, the tube bundle 15 has three heat exchanger tubes 6 with different radii of the bend regions 3 matching each other arranged in each other, and these three groups have nine inlets 12 and outlets 13 with casing covers. 4 are formed side by side so as to penetrate through 4.

  FIG. 1c shows the heat exchanger 1 with a tube bundle 15 consisting of flat tubes according to a side view, showing the wide side of the heat exchanger tube 6 established as a flat tube. The straight tube end 2 bends at one end to the bend region 3 and forms the end 11 of the heat exchanger tube 6 at the other end.

  FIG. 2 shows a heat exchanger 1 having a tube bundle 15 consisting of flat tubes according to an exploded view, and when the casing 5 is closed in the upper region of the figure, the cooling liquid filled therein is sealed in the outside environment. The jacket part 5 with the seal 14 is shown assuring against. In the lower region, a tube bundle 15 connected to the casing cover 4 is shown. The heat exchanger tubes 6 formed as flat tubes and bent into a U shape on the narrow side plane are bundled in a dense package in which the heat exchanger tubes 6 are arranged side by side in a curved region 3 and are arranged side by side. It can be seen that it forms.

  The end 11 of the heat exchanger tube 6 passes through the casing cover 4 and is fixed to the casing cover 4. After passing through the casing cover 4, the heat exchanger tubes 6, ie the ends 11 of the heat exchanger tubes 6, each form an interface 7 that is used to connect the heat exchanger 1 to the automobile exhaust gas system. Specifically, the exhaust gas flows into the inlet 12 and the exhaust gas cooled after the heat is transferred flows out of the heat exchanger 1 through the outlet 13.

  The heat energy carried by the exhaust gas leaving the engine combustion chamber at high temperatures is dissipated into the coolant. The cooling liquid flows into the heat exchanger 1, particularly into the jacket part 5 of the casing. As a result, the coolant flows in and out through the opening in the casing cover 4, the coolant inlet 9 and the coolant outlet 10.

  In order to avoid a short circuit flow inside the casing, a partition wall is attached to the casing cover 4 and the partition wall projects into the U-shaped bend of the heat exchanger tube 6 having the smallest radius. This partition wall forces the coolant to flow extensively along the heat exchanger tube 6 instead of the shortest path near the casing cover 4 from the coolant inlet 9 to the coolant outlet 10.

  In a preferred embodiment, the casing jacket 5 is made of a material having a low melting point, in particular a synthetic resin. However, the jacket portion 5 may be made of another material having a low melting point, for example, aluminum. The material used must only meet the requirements set by the use of the cooling medium. This requirement is primarily related to pressure, temperature, and chemical resistance. The chemical resistance is particularly important when oil is used as a cooling medium. Cooling water with additives can also set special requirements for chemical resistance. Thereby, even in the illustrated case of using a heat exchanger as the exhaust gas cooler, a material having a low melting point such as a synthetic resin or aluminum that can be well below 1000 ° C. can be used for the jacket portion 5. Such materials usually cannot withstand exhaust gas temperatures. This gives rise to the preferred possibility that the material for the cooler casing, in particular the jacket part 5, can be chosen very freely and consequently has a decisive influence on the price and weight of the finished product in particular. A lightweight and inexpensive material can be used.

  FIG. 3a shows a heat exchanger 1 having a tube bundle 15 of flat tubes bent sideways according to a top view, unlike FIG. 1a, the view is in the direction of the wide side of the flat tube. The total heat exchanger tube 6 is a completely flat tube. In the illustrated embodiment, the flat tube is U-shaped on the wide side plane.

  FIG. 3b shows the heat exchanger 1 with a tube bundle 15 of flat tubes bent sideways according to a front view, as shown in FIG. 1b, shown by a tube passage in which the casing cover 4 is arranged uniformly. . Only two U-shaped bent portions of the heat exchanger tube 6 are arranged in each other depending on the orientation of the cross section of the flat tube, but these five groups are stepped up and down each other. Thereby, there are 10 inlets 12 and 10 outlets 13, respectively, through which exhaust gases flow into or out of the heat exchanger 1, respectively. Bending a flat tube on the wide side plane is technically difficult and requires a special technical solution.

  FIG. 3c shows the heat exchanger 1 with a tube bundle 15 of flat tubes bent sideways according to a side view, from the perspective of the narrow side direction of the heat exchanger tubes 6 formed as flat tubes. The straight pipe end 2 bends into a bend region 3.

FIG. 4 shows a heat exchanger 1 having a tube bundle 15 of horizontally bent flat tubes used as heat exchanger tubes 6 according to an exploded view. Here the upper part of the figure shows the casing jacket 5 as well as the associated seal 14.
The lower part shows a tube bundle 15 connected to a casing cover 4 consisting of heat exchanger tubes 6. The heat exchanger tube 6 is arranged so that the U-shaped bent portion is on the wide side plane. Both the straight tube end 2 and the bent region 3, as well as the finished heat exchanger tube 6 are made of flat tubes.
The tube bundle 15 protrudes from the upper surface of the casing cover 4, but the interface 7 is positioned at the bottom.

  FIG. 5a shows a heat exchanger 1 with a tube bundle 15 of flat tubes and circular cross-section tubes according to a top view, unlike the above illustration, in particular FIG. 1a with the same point of view towards the narrow side of the flat tubes, 6 is not limited to being made of flat tubes. The straight pipe end 2 formed of a flat pipe is bent and transferred to a pipe having a circular cross section in the bending region 3. The entire bending area 3 is formed by a tube having a circular cross section.

  The flow state changes in the bending region 3 or in the transition region between the straight pipe end 2 and the bending arcuate region 3 due to the change of the cross section. Turbulence is generated at the time of inflow into the bend region 3 having a circular cross section. Further, the flow resistance higher than that in the straight pipe in the bending region 3 is reduced by expanding the cross section.

  FIG. 5b shows a heat exchanger 1 having a tube bundle 15 (not shown) consisting of a flat tube and a circular cross-section tube in front view, and the arrangement of tube ducts passing through the casing cover 4 is not different from that shown in FIG. 1b.

  FIG. 5 c shows the tube bundle 15 of the heat exchanger 1 consisting of a flat tube and a circular cross-section tube according to a side view, looking at the wide side of the straight tube end 2. Furthermore, a transition region 16 that appears trapezoidal in a side view is shown. This transition region serves to match the rectangular cross section of the flat tube with the circular cross section of the tube portion forming the bending region 3.

  FIG. 6 a shows the casing 5 and the seal 14 of the heat exchanger 1 with a tube bundle 15 of flat tubes and circular cross-section tubes according to a perspective view. The jacket part 5 and the seal 14 are shown.

  FIG. 6 b shows the tube bundle 15 and the casing cover 4 of the heat exchanger 1 consisting of a flat tube and a circular cross-section tube according to a perspective view. The casing cover 4 is fitted to the straight pipe end 2 forming the interface 7 at the bottom of the casing cover 4. Besides the straight tube end 2, the heat exchanger tube 6 is formed by an arcuate region 3. Unlike the straight tube end 2 formed of a flat tube, the bent region 3 is formed of a tube having a circular cross section.

  FIG. 6c shows the tube bundle 15 and the casing cover 4 of the heat exchanger 1 having a flat tube and a circular cross-section tube according to a side view by showing at least the wide side outside the heat exchanger tube 6 formed by a flat tube. However, flat tubes are used only in the region of the straight tube end 2, whereas the bent region 3 is formed by a tube having a circular cross section. A feature of the preferred embodiment of the invention is shown in the side view as the width of the heat exchanger tube 6 is reduced in the bending region 3.

  FIG. 7a shows a heat exchanger 1 having a tube bundle 15 of flat tubes and circular cross-section tubes arranged sideways by a front view. The bending of the pipe connected to the flat tube of the heat exchanger 1 is directed to the short sides. At the upper end, the two straight pipe ends 2 communicate with each other via a bending region 3 which is configured as a circular cross-section pipe in the illustrated embodiment. The transition region 16 ensures a cross-sectional fit between the flat tube and the circular cross-section tube. The fluid tight passage 17 seals the internal space of the heat exchanger 1 from the outside environment in the region of the tube passage.

  FIG. 7 b shows a heat exchanger 1 having a tube bundle 15 of flat tubes and circular cross-section tubes arranged sideways by a top view, not illustrated by the arrangement of the straight tube end 2 passages through the casing cover 4, It shows that five inlets and five outlets of the bent heat exchanger tube 6 are positioned on the casing cover 4.

FIG. 7 c shows in side view a heat exchanger 1 having a tube bundle 15 of flat tubes and circular cross-section tubes arranged sideways, showing the flat side of the flat tube forming the straight tube end 2. Over the transition region 16, the flat tube bends and transitions to a circular cross-section tube forming the exemplary bend region 3 of the illustrated embodiment.
In a further embodiment of the solution according to the invention, it is particularly advantageous that the heat exchanger tubes 6 positioned one above the other are in a cleverly staggered arrangement (offset arrangement). Thereby, a high package density can be achieved in the bend region 3 or the turning region, despite the change to a circular geometry.

  FIG. 8a shows the heat exchanger 1 with a tube bundle 15 consisting of flat tubes and circular cross-section tubes arranged sideways in a perspective view, showing the tube bundle 15 and the casing cover 4 in detail. The coolant inlet 9 and the coolant outlet 10 are disposed on the casing cover 4. In order to prevent a short circuit flow between the coolant inlet 9 and the coolant outlet 10, the partition wall 8 is positioned in a possible short circuit flow path and extends between the casing cover 4 and the bend region 3.

  FIG. 8b shows the heat exchanger 1 with a tube bundle 15 consisting of flat tubes and circular cross-section tubes arranged sideways in a perspective view, where a jacket part 5 with a seal 14 is shown.

  FIG. 8 c shows the heat exchanger 1 having a tube bundle 15 consisting of flat tubes and circular cross-section tubes arranged sideways, again according to the representation of the tube bundle 15, the partition wall 8 and the casing cover 4, in this case shown in a side view. . Here, it can be seen how the flat tube at the straight tube end 2 that appears narrow in this figure bends and transitions to the wider circular cross-section tube in the bending region 3 positioned on the right hand side of the figure.

  According to a variant of the solution according to the invention, it is shown to be particularly useful that the heat exchanger tubes 6 positioned one above the other are cleverly staggered. Thereby, a high package density can be achieved respectively in the bend region or in the turning region, despite the change to a circular geometry.

FIG. 9a shows the heat exchanger 1 with tube bundles 15 arranged in an offset arrangement of flat tubes and circular cross-section tubes according to a top view. Here, it is shown that the straight tube end 2 bends over the transition region 16 to the bend region 3. The bend region 3 is illustrated in the figure by a cross section made of a circular cross-section tube and enlarged in the bend region 3 in the illustrated embodiment.
In a preferred embodiment of the present invention, the heat exchanger tubes 6 configured as flat tubes are arranged so that the wide sides of the flat tubes face each other. The bent heat exchanger tubes 6 having different heights in three groups are positioned above and below each other or within each other.
The arrows indicate the direction of fluid flow in the pipe, which in the preferred embodiment is the exhaust gas of an internal combustion engine.

  FIG. 9b shows the casing cover 4 of the heat exchanger 1 in front view. The passage of the straight pipe end 2 configured to be fluid-tightly sealed while penetrating the casing cover 4 is disposed offset.

  Three groups of bent heat exchanger tubes 6 of different height, not shown in the figure, are positioned slightly offset laterally with the direction of flow, and in a particularly preferred exemplary embodiment, the offset is flat. It is half the length of the long side of the cross section of the tube.

  Similarly, a group of bent heat exchanger tubes 6 that together form a tube bundle 15 (not shown here) is composed of a flat tube and a circular cross-sectional tube, and the flat tube is used in the region of the straight tube end 2, A circular cross-section tube is used for the bending region 3.

  FIG. 9c shows a tube bundle 15 offset from the heat exchanger 1 in a side view, the tube bundle 15 comprising a flat tube and a circular cross-section tube. Here, it can be seen that the wide side of the flat tube forms the region of the straight tube end 2. After the transition region 16, the heat exchanger tube 6 bends and transitions to the bending region 3 formed as a circular cross-section tube.

  FIG. 10a shows the heat exchanger 1 with an offset tube bundle 15 consisting of flat tubes and circular cross-section tubes arranged sideways by top view. In the illustrated preferred embodiment of the present invention, the heat exchanger tube 6 is formed as a flat tube and is arranged so that the narrow sides of the flat tube face each other. The three groups of bent heat exchanger tubes 6 having different heights are respectively arranged above and below each other or within each other.

  It is particularly useful that the heat exchanger tubes 6 positioned one above the other are in a cleverly offset arrangement. Thereby, a high package density can be achieved respectively in the bending region or in the turning region, despite the bending change to a circular geometry.

  FIG. 10b shows the heat exchanger 1 with tube bundles 15 arranged in an offset arrangement consisting of flat tubes and circular cross-section tubes arranged sideways by front view. The passage of the straight pipe end 2 is shown on the casing cover 4. Each of the three groups of straight tube ends 2 includes an inlet 12 and an outlet 13 and is part of a heat exchanger tube 6 having a different bend height, not shown here, and the inlet 12 of each passage. And an outlet 13 is marked on the casing cover 4. Thereby, the figure shows that the preferred embodiment shown here includes five single heat exchanger tubes 6 in each group.

  FIG. 10c shows the tube bundle 15 of the heat exchanger 1 having an offset tube bundle 15 consisting of flat tubes and circular cross-section tubes arranged sideways by side view. This figure shows the narrow side of the flat tube forming the straight tube end 2. On the right side of the figure, a transition region 16 and a cross section of a circular section tube forming a further bending region 3 are shown.

FIG. 11a shows a heat exchanger 1 having an offset tube bundle 15 consisting of flat tubes and circular cross-section tubes arranged sideways in a perspective view, the tube bundle 15 being shown in a compact package, in particular here In a preferred embodiment, it comprises a plurality of heat exchanger tubes 6, which are eleven heat exchanger tubes. The flat tubes face each other on these narrow sides.
The heat exchanger tube 6 is fixed in the casing cover 4 and forms an interface 7 on the back surface of the casing cover 4.

  FIG. 11 b shows the heat exchanger 1 with an offset tube bundle 15 consisting of flat tubes and circular cross-section tubes arranged sideways in an exploded view, with the jacket part 5 and the seal 14 displayed, A tube bundle 15 consisting of flat tubes and circular cross-section tubes arranged is not shown.

FIG. 12a shows a heat exchanger 1 having an offset tube bundle 15 consisting of a flat tube and a circular section tube in perspective view, the tube bundle 15 being in a closely packed package, in the particularly preferred embodiment shown here. A plurality of heat exchanger tubes 6 which are eleven heat exchanger tubes are provided. The flat tubes oppose each other on their wide side surfaces.
The heat exchanger tube 6 is fixed in the casing cover 4 and forms an interface 7 on the back surface of the casing cover 4. The partition wall 8 protruding vertically from the casing cover 4 prevents a short circuit flow of the coolant that circulates freely inside the heat exchanger 1.

  FIG. 12b shows the heat exchanger 1 with an offset tube bundle 15 consisting of a flat tube and a circular cross-section tube according to an exploded view, with the jacket part 5 and the seal 14 shown, but from the flat tube and the circular cross-section tube. The resulting tube bundle 15 is not shown.

  The outer surface of the heat exchanger tube 6 used in the preferred exemplary embodiment comprises a spirally embossed groove. As a modification of this embodiment, a smooth heat exchanger tube 6 that is not embossed may be used.

FIG. 13a shows the heat exchanger 1 with tube bundles 15 arranged in an offset arrangement consisting of flat tubes and circular cross-section tubes arranged sideways in a perspective view. Unlike the preferred embodiment shown in FIG. 12a, which has a smooth or spirally grooved tube wall of the heat exchanger tube 6, the tube wall of the alternative embodiment shown here provides a more severe structure. It has been. This structure is applied to both the region of the straight tube end 2 and the region of the bending region 3. In the illustrated embodiment, a rectangular recess structure is used. The quadrangular recess is applied to the wide side of the flat tube, is arranged with an offset like a mosaic pattern, and protrudes into the flow cross section of the flat tube. Thereby, the square recess prevents the laminar flow from developing, causing the exhaust gas to swirl in the heat exchanger tube 6 and in a preferred embodiment of the invention the exhaust gas flows through the heat exchanger tube 6. . The swirling vortex destroys the developing boundary layer, resulting in improved heat transfer. In particular, this rectangular recess structure increases the heat exchange surface and further enhances the heat exchanger capability.
Apart from the mosaic-like structure preferred in the illustrated embodiment, and also the annular or helical structure and the smooth surface of the wall of the heat exchanger tube 6 are provided by the present invention.

  FIG. 13b shows the heat exchanger 1 with the tube bundle 15 arranged in an offset arrangement, consisting of flat tubes and circular cross-section tubes arranged sideways in the exploded view, with the jacket part 5 and the seal 14 shown, And the tube bundle 15 consisting of a circular cross-section tube is not displayed.

DESCRIPTION OF SYMBOLS 1 Heat exchanger 2 Straight pipe end 3 Bending area 4 Casing cover 5 Jacket part, casing 6 Heat exchanger pipe 7 Interface 8 Partition wall 9 Coolant inlet 10 Coolant outlet 11 End of heat exchanger pipe 12 Heat exchanger pipe Inlet 13 Heat exchanger tube outlet 14 Seal 15 Tube bundle 16 Transition region 17 Passage

Claims (14)

A heat exchanger (1) for use in a motor vehicle, which is arranged in a separately formed and closed casing and in which a coolant flows around its outer surface and flows separately Having a tube (6),
The casing comprises at least a casing cover (4) and a jacket part (5), the jacket part (5) is sealed by the casing cover (4), and both ends (11) of the heat exchanger pipe (6) are Through the casing cover (4) in an airtight and liquid tight manner so that the inlet (12) and outlet (13) of the heat exchanger tube (6) are arranged outside the casing;
Furthermore, it has a tube bundle (15) with a U-shaped bent region (3) having a circular cross-sectional shape between the straight tube ends (2),
The tube bundle (15) is at least partly formed from flat tubes arranged in a row above and below each other and formed in a rectangle at least in the region of the straight tube end (2);
U-shaped bending regions (3) positioned above and below each other of the heat exchanger tubes (6) of the tube bundle (15) so that the tube bundle (15) achieves a high package density in the U-shaped bending region (3). The heat exchanger (1) is an exhaust gas heat exchanger, particularly a heat exchanger (1), characterized in that the cooling fins connected to the tube bundle (15) are omitted. ).   2. A heat exchanger (1) according to claim 1, characterized in that the straight tube ends (2) of the flat tubes oppose each other on their narrow sides.   2. A heat exchanger (1) according to claim 1, characterized in that the straight tube ends (2) of the flat tubes oppose each other on their wide side surfaces.   The heat exchanger (1) according to any one of claims 1 to 3, characterized in that the tube cross section of the U-shaped bend region (3) has a rectangular or elliptical cross-sectional shape.   5. A heat exchanger (1) according to any one of claims 1 to 4, characterized in that the heat exchanger tube (6) of the tube bundle (15) comprises a surface provided with a structure.   Heat exchanger (1) according to any one of the preceding claims, characterized in that a plurality of U-shaped heat exchanger tubes (6) are combined in each other in the tube bundle (15). .   At least two U-shaped heat exchanger tubes (6) having an equal radius U-shaped bend region (3) and an equal length straight tube end (2) are positioned side by side and have at least two different radii 7. A heat exchanger (1) according to any one of the preceding claims, characterized in that two U-shaped heat exchanger tubes (6) are positioned in each other. Heat exchanger (1) is, as the heat exchanger (1) is used in automotive exhaust gas line, heat according to any one of claims 1 7, characterized in that it is formed Exchanger (1). 9. Heat exchanger (1) according to claim 8 , characterized in that the casing cover (4) forms an interface (7) for connecting the heat exchanger (1) to an automobile exhaust gas system. Heat exchange according to claim 8 or 9 , characterized in that the multiple heat exchanger tubes (6) arranged in the casing comprise forming a fluidly switched tube bundle (15) in parallel. Vessel (1). The heat exchanger (1) forms a coolant inlet (9) and a coolant outlet (10), and the coolant inlet (9) and / or the coolant outlet (10) is arranged in the casing cover (4). The heat exchanger (1) according to any one of claims 8 to 10 , characterized in that Heat exchanger (1) A heat exchanger (1) is any one of the preceding claims, characterized in that it is designed to be used in the coolant-cooled charge air cooler of the automobile 7 The heat exchanger (1) described in 1. 8. The heat exchanger (1) according to any one of claims 1 to 7 , characterized in that the heat exchanger (1) is designed for use in an automotive coolant-cooled oil cooler. The heat exchanger as described (1). Jacket of the casing (5) is a heat exchanger according to any one of claims 1 to 13, characterized in that it consists of a material having a melting point of 1000 ° C. or less (1).

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