INTERCAM BIADO R D E HEAT FOR ENGINES OF COM I NTERNAL BUSTION
Field of the Invention The invention relates to a heat exchanger for internal combustion engines according to the preamble of claims 1, 7, 21 and 24. Background of the invention In the modern construction of motor vehicles having internal combustion engines, the heat exchangers are used every day, by means of which the heat of the exhaust gases is transported to a coolant. This may be desirable for the purposes of rapidly heating the refrigerant or for the purpose of cooling the exhaust gas, for example in combination with the recirculation of exhaust gas. In this case, there are problems with respect to exhaust gas con- duction and also the construction space in particular in combination with other components and an idad. DE 1 02 03 003 A1 discloses a heat exchanger for exhaust gases in which the first and second flow channels for the exhaust gases are placed in parallel in a common housing, a valve channel placed upstream of the exhaust channels. flow that has the same flow direction as the flow channels, this means it is placed linearly with respect to the flow channels.
DE 100 25 877 A1 discloses a heat exchanger for exhaust gases in a plurality of embodiments in which a respective valve channel positioned upstream of the flow channels has an identical flow direction on the input side as the channels of flow, this means it is placed linearly with respect to the flow channels. Brief Description of the Invention The object of the invention is to describe a heat exchanger mentioned at the beginning which is especially advantageous with respect to the exhaust gas pipeline. According to the invention, this object is achieved for a heat exchanger mentioned at the beginning by means of the features of claim 1. This advantageously achieves the effect that the heat exchanger can be placed in a flexible manner even in a limited construction space, for example in the engine compartment of a motor vehicle. Furthermore, it is advantageous that the valve element is not placed on the same flow axis as the flow channels, since the dependent standing waves formed from the velocity by the pulsating exhaust gases of the internal combustion engines have both Less effect on the mechanism of the valve element. In the same way, vibrations directed longitudinally or transversely of the heat exchanger housing in the region of the valve channel are reduced, which is equally favorable for operation and
service life of the valve mechanism. In a preferred embodiment of a heat exchanger according to the invention, the valve channel is positioned upstream of the flow channels and an inlet channel is placed upstream of the flow channel in the flow direction of the valves. exhaust gases, wherein in an especially preferred manner, a flow axis of the inlet channel has a different direction of the flow axis of the valve channel and from the flow axes of the flow annals. This makes possible the radial bending of the exhaust gas pipeline in such a way that a flow of the exhaust gas can be ensured without problems in a construction of a smaller type. In this case, an angle between the flow axis of the valve channel and the flow axis of the inlet channel is in particular preferably greater than 30 degrees in order to obtain a sufficiently large deviation of the exhaust gas flow. The angle between the flow axis of the valve channel and the flow axis of the flow channel is preferably preferably greater than 30 degrees, particularly preferably greater than 40 grams. In this case, the angle between the flow channel and the valve channel and between the valve channel and the inlet channel may increase with respect to the exhaust gas conduction in order to achieve in particular a large deviation of the gas flow of escape in general without having to tolerate the disadvantages associated with an appreciable degree. In particular the conduction of the exhaust gas which is unfavorable with respect to the swirl and flow resistance is avoided and
which forces a deviation of the gas flow of 90 degrees in the smallest space. In order to avoid the aforementioned disadvantages to a particular degree, the angle between the flow axis of the valve channel and the flow axis of the flow channel is in particular less than 60 degrees. This does not conflict with the aforementioned two-stage deviation of the output gas flow with a total angle of approximately 90 degrees. In a preferred embodiment of the invention, an average flow length of one of the channels is greater than the average flow length of the valve channel by at least a factor of two, in particular by a factor of 2.5. Here the term "flow length" refers to the path length by means of the exhaust gases, that is to say approximately the path along the axis of symmetry of an exhaust gas channel. In this way, based on the dimensions of the flow channels resulting from the capacity of the predetermined heat exchanger, a particularly compact type of construction of a heat exchanger according to the invention is achieved. In addition, the valve element preferably only has one fin element, and therefore only a small number of components are required. With respect to a correspondingly simple and effective mechanism of the valve member, the fin member fits into a shaft that can be rotated with the
application of energy. The particular valve channel preferably has a dividing wall adjacent to the fin member, at least the sections of the valve channel are divided into two valve channel halves by means of the divider wall. This allows for a simple construction and an exhaust gas line with low swirl. In a preferred embodiment of the invention, the second flow channel is positioned essentially parallel to the first flow channel and the first flow channel and the second flow channel are in particular placed in a common housing. This in each case promotes a compact type of construction of the heat exchanger. Furthermore, the object of the invention is achieved by means of those of claim 1. Due to the contact between the valve element and the molded portion, it is advantageously possible that one of the flow channels in each case can be closed in a special manner. effective against the passage flow of exhaust gases. In addition, premature material wear in the contact region between the valve element and the valve channel can be avoided in a simple manner. The valve channel in this case advantageously has a circular cross-section, and the molded portion can be formed by deforming a wall of the valve channel, in particular by means of troquelation. As a result, the molded portion can be produced in a simple and inexpensive manner.
Furthermore, the object of the invention is achieved by means of the features of claim 18. The double wall of the second flow channel makes possible a particularly good insulation of the exhaust gas, which flows through this channel against heat exchange . The second flow channel in this case advantageously has an inner tube that is placed in a housing, an outer surface of the inner tube being at a distance from the housing. This allows the construction of the heat exchanger to remain generally small wherein a further combination of the housing with the first flow channel to form a building unit is advantageously advantageous. The distance of the housing from the inner tube can be advantageously fixed by means of of separators. The latter can have a plurality of studs placed on the outer surface of the inner tube, as a result of which a double wall of the second channel with good thermal insulation can be realized by simple means. Advantageous provisions are also taken so that the inner tube is directly connected to a deflection plate, the deflection plate is placed in the valve channel. In a particularly advantageous manner, the valve element in this case is movably positioned on the deflection plate and the valve channel is directly connected to the housing. This results in a reliable and simple sequence during the
production of the heat exchanger according to the invention by virtue of the fact that the first of all the deflection plates, the inner tube and the housing are oriented to each other and are connected to each other. After this, the valve channel can be placed on the deflection plate and oriented with respect to the latter and connected to the housing. The respective connection can be made by welding or brazing, other types of fixation can not be excluded. Depending on the requirements, the valve element of the device according to the invention can be rotatably mounted on the valve channel in a single support bracket. Alternatively, the valve channel assembly can also be provided at two separate support points. Furthermore, the object of the invention is achieved by means of the features of Claim 27. Due to the design of at least two parts of the valve channel housing, it is advantageously possible to produce the complicated shapes of the valve channel in a simple manner with regarding the optimized exhaust gas conditioning. Preferably in this case the provisions are taken for the valve element to be placed between the parts of the housing first and second, where in a particularly advantageous manner, it is movably mounted in at least one of the half portions of the housing. accommodation . This makes possible a simple assembly of the heat exchanger even with the complex shape of the
parts and also allows by means of the appropriate monitoring during the assembly, of the functionally reliable assembly of the valve element even when dimensional tolerances of the components are present. The housing parts advantageously are fixedly connected to each other, in particular by means of welding. As a result a high degree of gas tightness can be combined with a high thermal resistance. Alternatively, other heat resistant connections can be provided such as welding for example. The connection of the housing parts by means of screws or flanges or flanges is also possible, it is probably necessary that additional sealing means are provided with respect to the gas tightness depending on the requirements. In the interest of cost-effective production at least one of the housing parts is preferably designed as a molded part, in particular an extruded part. Furthermore, this advantageously allows the use of materials whose production by means of molding processes is problematic, such as, for example, high-quality steel. Needless to say, the two-piece design of the valve channel does not contradict any of the aforementioned characteristics of the invention, and therefore each of the aforementioned characteristics can be combined with the design of two parts of the valve channel . In particular the molded portions
mentioned above for the flat contact of the valve element can be formed in the housing portions of the valve channel. In particular the design of the housing parts as molded parts, these molded shapes of the valve channel wall can advantageously be formed in the course of the molding process. Other features and advantages can be seen from the exemplary embodiment described below and from the dependent claims. Brief Description of the Figures Three preferred exemplary embodiments of the heat exchanger according to the invention are described below and explained in more detail with reference to the accompanying drawings. Figure 1 shows a plan view of a first exemplary embodiment of a heat exchanger according to the invention. Figure 2 shows the heat exchanger according to Figure 1 rotated by 90 °. Figure 3 shows the heat exchanger according to Figure 2 rotated by 90 °. Figure 4 shows an end view of the heat exchanger according to Figure 1. Figure 5 shows a schematic section through the valve channel of the heat exchanger in the orientation according to Figure 2. Figure 6 shows a three-dimensional illustration dismembered from a detail of the heat exchanger of figure 1. Figure 7 shows a three-dimensional illustration of a second exemplary embodiment of a heat exchanger according to the invention. Fig. 8 shows a detailed view of the heat exchanger of Fig. 7, showing the interior of the valve channel. Fig. 9 shows a three-dimensional view of the valve element of the heat exchanger of Figs. 7 and 8. Fig. 1 0 shows a three-dimensional view of a third exemplary embodiment of a heat exchanger in accordance with Figs. invention, partially showing the internal components of the heat exchanger. Figure 1 1 shows a schematic plan view of a detail of the heat exchanger. Figure 1 2 shows a side scan view of the detail of Figure 1 1. Figure 1 3 shows a schematic front view of! detail of fig. 1 1. Figure 14 shows a schematic plan view of an internal tube of the heat exchanger of Figures 1 to 1 3. Figure 1 5 shows a three-dimensional view of a detail of a heat exchanger according to the invention. Fig. 1 6 shows a three-dimensional view of a modification of a valve channel of the second mode
Example of a heat exchanger according to Figure 7 to 9. Figure 1 7 shows the valve channel of Figure 1 6 from another three-dimensional perspective Figure 1 8 shows the valve channel of Figure 1 from another three-dimensional perspective Detailed Description of the Invention The heat exchanger according to a first embodiment of the invention has a first flow channel 1 and a second flow channel 2, the first flow channel in this case is designed as a plurality of parallel individual channels (see Figure 6). Figure 6 shows that two flow channels are placed parallel to each other and are arranged in the same housing 3. A conduit 4 for conducting a liquid refrigerant is likewise directed in the housing 3 and leaves the housing in a connection of the input side 4a and the respective connection 4b. Within the housing the conduit 4 is in substantial thermal contact only with the first flow channel, such that a relevant heat exchange takes place between the exhaust gas and the refrigerant only when the exhaust gas flows through the first flow channel 1 . In the flow direction S of the exhaust gases, the heat exchanger has at its end an outlet channel 5, which in this case, with respect to the outflow gas flow, is oriented parallel to the flow channels. However for the requirements
However, an outlet channel 5 extending at an angle to the flow channels 1, 2 may be provided. Upstream of the flow channels 1, 2 in the flow direction S there is a valve channel 6, which is welded to the housing 3. The valve channel 6 has a circular cross-section and is connected to the housing 3 with an angle W1 of approximately 42 ° to the flow channels 1, 2. This angle is between a flow axis of the input side SV and respective flow axes SK1, SK2 of the first flow channel 1 and the second flow channel 2 (see Figure 2). Welded in the place upstream of the valve channel 6 in the flow direction S is an inlet channel 7, which can be connected on the inlet side to another line of exhaust gas by means of a flange 7a. A flow axis of the input side SE of the input channel forms an angle W2 of 35 ° with the flow axis of the input side SV of the valve channel. The angles W1 and W2 lie in a plane, such that the flow axes Se of the input channel and the flow axis SK1, SK2 of the flow channels 1, 2 form a total angle of 77 °. Alternatively, however, the angles can be in different planes and can deviate from the present values in order to allow adaptation to the conduction of the exhaust gas in each case. A fin member 8 is designed as a fin which can be moved in an energized manner is accommodated in the valve channel 6 (see Fig. 5). The fin 8 is firmly connected to the
Rotating shaft 9 extends at the end of one end edge of the fin 8 and perpendicularly through the valve channel 6. In addition, a fixed deflection plate 10 is provided in the valve channel, the plate Deflection 1 0 forms a continuation of the valve flap. Due to the deflection plate 10, an end region on the outlet side of the valve channel is subdivided into a first valve channel half 6a and a second valve anal half 6b, each one of the channel halves of the valve channel. valve 6a, 6b are respectively connected to one of the fiow channels 1, 2. A valve element is therefore generally formed by means of the deflection plate 10, the vane 8 and the shaft 9, by means of the valve element the exhaust gas flow can optionally be directed in at least two channels d iferentes. At the edge opposite the axis 9, the flap 8 is formed in a curved or elliptical manner in order to obtain a sealing fit in relation to the wall of the valve channel 6, which has a circular cross-section. The wall of the valve channel can be processed appropriately in the contact region of the valve flap. The flap 8 can be moved by means of an impu tion 1 1 on the shaft 9, the drive 1 1 in this case consists of an air damper 12, which can be moved by means of a push rod 14. L thrust 14 is connected to the end by means of a ball-and-socket joint to a pivot pin 1 3 fixed to the axle 9. As a result of a push or pull movement of the push rod
14 leads to a rotation of the shaft 4 and therefore even adjustment of the flap 8. Depending on the position of the flap, the exhaust gas can not be directed through the first flow channel 1 which is used for the exchange of heat or can be directed through the flow channel 1 in any desired proportion or completely through it. The heat exchanger advantageously has the dimensions that it has a small size without impeding the flow of the exhaust gas. The average fl ow lengths of the two flow channels 1, 2 each are equal and correspond to the geometric position of the two channels. An average flow length of the valve channel 6 has approximately the geometric length of a central line of the valve channel 6. In this case the average flow length of a flow channel 1, 2 is approximately 2.7 times larger than the flow length. Average flow length of the valve channel 6. Therefore the majority of the overall nature of the heat exchanger is available for the actual heat exchange while maintaining the advantages of the invention. The heat exchanger according to the second exemplary embodiment (FIG. 7, FIG. 9) has, as in the first exemplary embodiment, a valve channel 6 which is positioned at an angle to the flow channels 1, 2. The valve element 15 has a deflection plate 10, in which a valve flap 8 arranged on the shaft 9 is placed. The valve channel 6 has a section having a
essentially circular cross section. Molded portions are provided in the wall of this section, with which a marginal region 8a of the fin 8 is in plane contact when the fin is in an extreme position. The contact with the first molded portion 16 is associated with the conduction of the exhaust gas flow through the second flow channel 2 and the contact with the molded portion 1 7 is associated with the conduction through the first flow channel. flow 1 Figure 8 shows the conduction through the second flow channel. The molded portions 1, 6, 17 are each produced by pressing a wedge with a corresponding shape on the wall of the valve channel 6, so that it can be observed from the outside. Due to the flat contact between the vane 8 and the molded portions 1 6, 17 the seal of the vane is improved and the vibratory tapping of the vane is contracted against the wall of the valve can 6. According to fig., the valve element 1 5 has a first support point 1 8 and a second support point 1 9 at a distance from the first. The shaft 9 is mounted with each of the respective support points on the valve channel 6, the first support point is assigned to an opening of the valve channel and the second support point 1 9 is still assigned a receptacle on the valve channel. cavity shape on the valve channel 6 on the opposite side of the opening. However, it can also be provided that the second support point 1 9 is omitted in such a way that the shaft is rotatably positioned on the valve channel 6 simply at the
region of a passage through the valve channel 6 at a single support point 18. In contrast to the previous exemplary embodiments, the heat exchanger according to a third exemplary embodiment (Figure 10 to Figure 14) has a valve channel 6 'which is oriented parallel to the flow channels 1, 2. The heat exchanger has a housing 3 in which a total of fifteen parallel tubes 1 a are placed, which together form the first flow channel 1. The refrigerant flowing through the housing 3 flows directly around the walls of the tubes 1 a. The second flow channel 2 is likewise accommodated in the housing 3. The flow channel 2 has an internal wall 3a, which is shown in dotted lines in figures 1 and 12, and is designed as a tubular passage open on both sides through the housing 3. In addition, the second flow channel has an internal tube 20, which is inserted into the passage. An outer surface of the tube 20 has a series of spacers 21 which are designed as studs projected on the outer surface of the inner tube 20. In the pushed state in the passage, only the studs 21 are in contact with the inner wall 3a of the tube. housing 3 (see in particular figure 13), in such a way that the thermal contact between the passage of the housing through which the coolant flows and the inner tube 20 through which the exhaust gas flows is very small. In general, a double wall of the second flow channel 2 with a first wall (passage of
housing 3a) and a second wall (inner tube 20) is formed by means of the arrangement described. The inner tube 20 and the housing passage 3a have an elongated cross section and end level with each other at their respective end faces. In contrast to Figure 10 the detailed illustration according to Figure 15 shows a valve channel with angled orientation, but corresponds to the third exemplary embodiment with respect to re-arrangement and fixing the housing 3, the inner tube 20 and the valve element 15. The illustration in figure 15 shows a preferred sequence for the adjustment and fixing of the components: the deflection plate 10 has an angular range 10a with an opening adapted to the cross section of internal tube 20. Firstly, nothing the deflection plate 10 is welded to an end face of the inner tube 20 around the margin of the opening. This unit is then pushed into the passage 3a of the housing 3, good frictional retention of the inner tube is obtained in a regular manner corresponding to the studs 21. The inner tube and / or the deflection plate 10 is substantially welded to the housing, with spot welding possibly sufficient. After this the valve channel 6 is pushed on the deflection plate 10 and if necessary the valve flap 8 and the shaft 9 are placed. After the precise orientation of the valve channel in relation to the valve element 15, the valve channel 6 solder to
housing by means of a weld extending around the front face of the housing. A modification of the heat exchanger according to a second embodiment of the invention which is particularly advantageous in particular with respect to the assembly is shown in figures 16 to 18. Here the reference to the second exemplary embodiment is only exemplary and the modification may be likewise combine with any of the other exemplary modalities. The outer wall of the valve channel in this case is not designed as a one piece housing but rather consists of a valve channel housing 30 which can be assembled from a first housing part 31 and a second housing part 32 The two housing parts here essentially have the shape of mirror mirroring halves, the plane of symmetry passes perpendicularly through the axis 9 of the valve element 9., 10, 1 1. The mirror symmetry is not exact in this case, since the shaft 9 passes through the first housing part 31 and is rotatably mounted on the first housing part 31 in the region in which the latter passes through. In the example shown, the assembly of the shaft 9 on the second housing part 32 is not provided. Alternatively, however, the shaft 9 can also be additionally mounted in a corresponding recess of the second housing part 32. Each of the parts of housing has a portion of a respective molded portion 16 17, already described in the second embodiment
exemplary, for the flat contact of the valve fin 8. For clarity the valve fin 8 or is shown in figure 16 to 18. The deflection plate 10, which is shown in figures 16 to 19, extends essentially from perpendicular to the plane of symmetry or transverse plane of the valve channel housing. Here the deflection plate 10 has dotted portions 10a at the end, which are engaged in correspondingly marginal portions of the housing portions 31, 32 and by means of which the deflection plate 10 is retained between the parts Assembled housing 31, 32. In addition to the simple retention with clamps, additional welding of the deflection plate 10 and the housing parts 31, 32 can be provided here. It should be noted that the deflection plate 10 is not fixedly connected to the shaft 9. rather, it extends only in its immediate vicinity or leans against the axis in a sliding manner with the appropriate precise fit. Each of the housing parts 31, 32 have been produced by means of extrusion from a corresponding template. In the fully assembled state of the heat exchanger, the housing portions which in particular are produced of high quality steel are fixed to each other by means of welding. The assembly of the heat exchanger is advantageously carried out in the region of the valve channel in the following manner:
First of all, the valve flap 8 is connected to its axis 9 (regularly by means of welding) and inserted rotatably into the first housing part 31. The housing parts 31, 32 are subsequently secured together by welding. Depending on whether the deflection plate 10 is held by clamps and / or by welding, it can be placed and fixed before or after the welding of the housing parts or also partially before or partially after welding. After the deflection pad 10 has been fixed, firstly using the inner tube 20 of the third exemplary embodiment, the inner tube 20 can be welded to the deflection plate 10. The advantageous conformation of the deflection plate 10 for this purpose it can be concluded from the description of the third exemplary modality. Finally, the valve channel 6", pre-equipped in this way, is assembled in the housing 3, possibly while pushing on the inner tube 20, and welded to this housing in a gas-tight manner.The assembly sequence described above As an example, it takes into account the fact that the exhaust gases first of all enter the region of the valve channel and therefore the particular valve channel is exposed to particularly high temperatures. also welding with brass or brazing, of the individual parts is the preferred means to connect the parts.
Depending on the requirements, the respective special characteristics of the described embodiments are not restricted to the exemplary embodiments but can be freely combined with each other, in which case the particularly advantageous heat exchangers can be formed if necessary for certain combinations. In particular, the molding, retention and adjustment of the inner tubes 20 can be applied to the first of two exemplary embodiments and the molded portions 16, 17 of the valve channel for the contact of the valve flap 8 are not restricted to channels of valves that have an angular orientation.