Plate-Type Heat Exchanger And Air-Conditioning Circuit For A Vehicle

Abstract

A plate-type heat exchanger (30) for a vehicle cools a cooling fluid by means of a coolant. The exchanger (30) has a plurality of heat exchanger plates (40) which are stacked one on top of the other. Coolant chambers (44) and cooling fluid chambers (46), which each have an inflow (48, 52) and an outflow (50, 54) for the coolant and/or the cooling fluid are formed between adjacent heat exchanger plates (40). The coolant and/or cooling fluid chambers (44, 46) are embodied in their entirety as U-shaped flow ducts (64, 68), wherein the assigned inflow (48, 52) is arranged at the end of a first limb, and the assigned outflow(50, 54) is arranged at the end of a second limb, of the flow ducts (64, 68). The invention also relates to an air-conditioning circuit (10) for a vehicle.

Description

The invention relates to a plate-type heat exchanger for a vehicle for cooling a cooling fluid by means of a coolant, having a plurality of heat exchanger plates which are stacked one on top of the other, and an air-conditioning circuit for a vehicle, in particular for a vehicle having an electric motor.

Plate-type heat exchangers of the type specified at the beginning are known in which the cooling fluid or the coolant flows through the intermediate spaces between adjacent plates, wherein the cooling fluid flows from a first side of the plate-type heat exchanger to the opposite second side of the plate-type heat exchanger, while the coolant flows in the opposite direction from the second end to the first end of the plate-type heat exchanger. The length of the flow ducts in the plate-type heat exchanger corresponds here essentially to the length of the plate-type heat exchanger from the first end to the second end. The outer dimensions of the plate-type heat exchanger and the position of the connections of the plate-type heat exchanger are therefore dependent on the desired length of the flow ducts in the plate-type heat exchanger.

The object of the invention is to provide a plate-type heat exchanger with a compact design as well as an air-conditioning circuit for a vehicle, which air-conditioning circuit can be embodied in a compact fashion which is optimized for the installation space.

The object of the invention is achieved by means of a plate-type heat exchanger for a vehicle for cooling a cooling fluid by means of a coolant, having a plurality of heat exchanger plates which are stacked one on top of the other, wherein coolant chambers and cooling fluid chambers, which each have an inflow and an outflow for the coolant and/or the cooling fluid, are formed between adjacent heat exchanger plates. The coolant and/or cooling fluid chambers are embodied in their entirety as U-shaped flow ducts, wherein the assigned inflow is arranged at the end of the first limb, and the assigned outflow is arranged at the end of the second limb, of the U-shaped flow duct. The U-shaped flow ducts make it possible to double the length of the flow duct of the coolant chambers and/or cooling fluid chambers without increasing the length of the plate-type heat exchanger, and to position the connections for the inflow and outflow of the coolant and/or of the cooling fluid in a flexible way.

The heat exchanger plates preferably have, in the plane of their plates, both a main extent direction and a secondary extent direction running perpendicular thereto, and are arranged one next to the other in a stacking direction which runs perpendicular to the main extent direction and to the secondary extent direction (referred to below as “definition of direction”).

With this predefined definition of direction it is advantageous that the inflow and outflow for the coolant are provided in the main extent direction, at the same end of the heat exchanger plates. In this way, the inflow and outflow for the coolant can be positioned near to one another without having to shorten the length of the flow duct for the coolant.

The heat exchanger plates can be substantially rectangular and the main extent direction can then run in the longitudinal direction of the plates.

A common inflow connection and outflow connection for all the coolant chambers is provided with a connection component which permits direct attachment of an expansion valve for the coolant to the plate-type heat exchanger. In this way it is possible to eliminate the need for a line system between the expansion valve and the plate-type heat exchanger.

In order to achieve a uniform cooling performance in all of the coolant chambers, the connection component can have a coolant distributor which homogenizes distribution of the coolant phase mixture among the various coolant chambers of the plate-type heat exchanger.

In the above-mentioned definition of direction, the inflow and outflow for the cooling fluid are provided at the same or at opposite ends of the heat exchanger plates in the main extent direction. This permits a variable arrangement of the connections for the cooling fluid.

For a flexible arrangement of the connections of the plate-type heat exchanger on a primary circuit and secondary circuit, in each case a common inflow connection and a common outflow connection can be provided for all the coolant chambers and in each case a common inflow connection and a common outflow connection can be provided for all the cooling fluid chambers, wherein the common inflow connection and outflow connection for the coolant are arranged in the stacking direction on the same lateral surface or on opposite lateral surfaces of the plate-type heat exchanger, as are the inflow connection and outflow connection for the cooling fluid.

An end plate can be provided on a common inflow connection and/or outflow connection for all the cooling fluid chambers, which end plate is arranged in front or behind the heat exchanger plates in the stacking direction and forms at least one flow duct for the cooling fluid, which flow duct connects the common inflow connection and/or outflow connection of the heat exchanger plates to a connection for a cooling fluid system. In this way, the end plate of the plate-type heat exchanger forms a type of adaptor which permits a compact and advantageously arranged connection to the cooling fluid system.

In the above-mentioned definition of direction, a further embodiment provides for the inflow and outflow for the coolant to be arranged in the main extent direction, at opposite ends of the heat exchanger plates, in the same way as the inflow and outflow for the cooling fluid. Given a corresponding orientation of the plate-type heat exchanger, this arrangement of the connections permits a connection for cooling fluid at the upper end of the heat exchanger plates and a connection for coolant at the lower end of the heat exchanger plates. This therefore easily permits, on the one hand, degassing of the cooling fluid chambers and, on the other hand, a return flow of oil in the coolant chambers.

The directions of flow in adjoining coolant chambers and cooling fluid chambers can be the same or opposite. The transmission of heat between the coolant and the cooling fluid along the flow duct can be optimized by the selection of the direction of flow of the coolant and cooling fluid.

According to a further embodiment, the heat exchanger plates can form a flow duct in the cooling fluid chambers, which flow ducts runs from an inflow of the cooling fluid at one end of the heat exchanger plates in the main extent direction to an outflow of the cooling fluid at the opposite end of the heat exchanger plates.

In order to improve the overall effectiveness of the exchange of heat between the cooling fluid and the coolant, the difference in pressure across the first limb of the U-shaped flow duct for the coolant is between 70% and 100%, preferably between 80% and 92% of the overall difference in pressure, and the difference in pressure across the second limb of the U-shaped flow duct for the coolant in the direction of flow is between 0% and 30%, preferably between 8% and 20% of the overall difference in pressure.

The U shape of the flow ducts is preferably formed by an intermediate wall which is provided by a part, which connects the adjacent heat exchanger plates, or by a shaped section of at least one heat exchanger plate. This permits a simple design of the plate-type heat exchanger.

In order to homogenize the distribution of the coolant or the cooling fluid in the U-shaped flow ducts, the limbs of the U-shaped flow ducts can be formed by numerous elongated ducts arranged one next to the other.

The invention also relates to an air-conditioning circuit for a vehicle, in particular for a vehicle having an electric motor, with a primary circuit for a coolant and a secondary circuit for a cooling fluid, wherein the primary circuit and the secondary circuit are coupled to the plate-type heat exchanger according to the invention. Since the plate-type heat exchanger itself is of compact design and has a flexible arrangement of the connections for the coolant and cooling fluid, a compact design which can be implemented in a flexible way is made possible for the air-conditioning circuit.

Further features and advantages of the invention can be found in the following description and in the following drawings, to which reference is made. In the drawings:

FIG. 1 shows a schematic view of an air-conditioning circuit according to the invention with a primary circuit for a coolant and a secondary circuit for a cooling fluid;

FIG. 2 shows a sectional view of a plate-type heat exchanger according to the invention along the sectional line II-II in FIG. 3;

FIG. 3 shows a plan view of the plate-type heat exchanger according to FIG. 2 in a stacking direction;

FIG. 4 shows a schematic view of the plate-type heat exchanger according to FIG. 2 with connections for the coolant and cooling fluid which are arranged on the same lateral surface of the plate-type heat exchanger;

FIG. 5 shows a schematic view of the plate-type heat exchanger according to FIG. 2 having connections for coolant and cooling fluid which are arranged on opposite lateral surfaces of the plate-type heat exchanger;

FIG. 6 shows a direction of flow diagram with associated temperature profile diagram according to a first embodiment of the invention;

FIG. 7 shows a direction of flow diagram with associated temperature profile diagram according to a second embodiment of the invention;

FIG. 8 shows a direction of flow diagram with associated temperature profile diagram according to a third embodiment of the invention;

FIG. 9 shows a direction of flow diagram with associated temperature profile diagram according to a fourth embodiment of the invention;

FIG. 10 shows a plate-type heat exchanger according to FIG. 9 with a first arrangement of the connections for the cooling fluid;

FIG. 11 shows a plate-type heat exchanger according to FIG. 9 with a second alternative arrangement of the connections for the cooling fluid;

FIG. 12 shows a plate-type heat exchanger according to FIG. 9 with a third alternative arrangement of the connections for the cooling fluid;

FIG. 13 shows a schematic view of four heat exchanger plates of a plate-type heat exchanger according to the invention;

FIG. 14 shows an alternative embodiment of four heat exchanger plates of a plate-type heat exchanger according to the invention;

FIG. 15 shows a view of a detail of the plate-type heat exchanger according to FIG. 2 with a coolant distributor; and

FIGS. 16a, 16b and 16c show schematic views of various embodiments of a coolant distributor according to FIG. 15.

FIG. 1 shows a schematic drawing of an air-conditioning circuit 10 for a vehicle with a primary circuit 12 for a coolant and a secondary circuit 14 for a cooling fluid.

The vehicle is, for example, a vehicle having an electric motor, in particular a hybrid vehicle or a pure electric vehicle, with a battery which is to be cooled by the air-conditioning circuit.

In the primary circuit 12, a compressor 16, a condenser 18 and a drier 20 are provided. The primary circuit 12 is divided into two secondary regions, which can each be closed or opened by a valve 22.

In the first secondary region of the primary circuit 12, an expansion valve 24 and vaporizer 26 are provided. The vaporizer 26 is part of a vehicle air-conditioning system for the passenger compartment of a vehicle.

An expansion valve 28 and a plate-type heat exchanger 30 are provided in the second secondary region of the primary circuit 12. The plate-type heat exchanger 30 is, furthermore, integrated into the secondary circuit 14 and permits a cooling fluid in the secondary circuit 14 to be cooled by the coolant in the primary circuit 12.

The secondary circuit 14 has a pump 32 which pumps the cooling fluid through the secondary circuit 14. The secondary circuit 14 also comprises a storage device 34 for the cooling fluid. A first cooling device 36 for a battery and a second cooling device 38 for an electronic component are arranged at various positions in the secondary circuit 14. The position of the cooling devices 36, 38 in the secondary circuit 14 can depend, in particular, on the required cooling performance.

FIG. 2 shows a sectional view through the plate-type heat exchanger 30. A plurality of heat exchanger plates 40 are stacked one on top of the other in a stacking direction 42, wherein coolant chambers 44 and cooling fluid chambers 46, which each have an inflow 48, 52 and an outflow 50, 54 for the coolant and/or the cooling fluid, are formed alternately between adjacent heat exchanger plates 40.

On the right-hand side in FIG. 2, an end plate 56 is provided which is arranged behind the heat exchanger plates 40 in the stacking direction. In the embodiment shown, the end plate 56 serves, for example, to attach the plate-type heat exchanger 30. The end plate 56 can also be part of a housing of the plate-type heat exchanger 30.

The heat exchanger plates 40 have, in the plane of their plates, both a main extent direction 58 and a secondary extent direction 60 running perpendicular thereto, said main extent direction 58 and secondary extent direction 60 each running perpendicular to the stacking direction 42. In FIG. 2, the secondary extent direction 60 runs perpendicular to the plane of the drawing.

The various inflows 48 of the various coolant chambers 44 lie in a straight line and therefore form a common inflow connection 49 for all the coolant chambers 44. At the common inflow connection 49, a connection component 62 is provided which permits direct attachment to the expansion valve 28 to the plate-type heat exchanger 30. Such expansion valves 28 have a small lateral distance between the inflow duct and the outflow duct. In the embodiments according to the invention, these ducts are coaxial to the inflows 48 and outflows 50.

In a way which is analogous to the inflows 48 of the coolant, the inflows 52 of the cooling fluid of the various cooling fluid chambers 46 also lie along a straight line and form a common inflow connection 53 for all the cooling fluid chambers. On the left-hand side of the plate-type heat exchanger 30, a pipe of the secondary circuit 14 is connected to the common inflow connection 53 of the cooling fluid chambers 46.

In a way which is analogous to the inflow connections 49, 53, all the outflows 50, 54 for the coolant and/or the cooling fluid are embodied as common outflow connections 51, 55.

FIG. 3 shows a plan view of the plate-type heat exchanger 30 in the stacking direction 42. The heat exchanger plates 40 are substantially elongate and rectangular, and the main extent direction 58 is in the longitudinal direction of the heat exchanger plates 40. Shown in the lower region of the plate-type heat exchanger 30 is the connection component 62 with the common inflow connection 49 of all the coolant chambers 44, and with the common outflow connection 51 of all the coolant chambers 44.

The distance between the inflow 48 and outflow 50 of the coolant of the coolant chambers 44 is small compared to the extent of the heat exchanger plates 40 in the main extent direction 58. As is shown in the following figures, this small distance permits the expansion valve 28 to be mounted directly on the plate-type heat exchanger 30 without pipes or lines for the coolant being required between the expansion valve 28 and the plate-type heat exchanger 30.

The common inflow connection 53 and the common outflow connection 55 of all the cooling fluid chambers 46 of the plate-type heat exchanger 30 are in turn arranged with small spacing in the upper region of the plate-type heat exchanger 30.

FIG. 4 shows a schematic view of the plate-type heat exchanger 30 in a plan view in the direction of the secondary extent direction 60. As can be clearly seen in this perspective, the common inflow connection 49 and the common outflow connection 51 for all the coolant chambers 44, and the common inflow connection 53 and the common outflow connection 55 for all the coolant chambers 46, are arranged on the same lateral surface of the plate-type heat exchanger 30 with respect to the stacking direction 42.

FIG. 5 shows an alternative arrangement of the inflow connection 53 and of the outflow connection 55 of the cooling fluid chambers 46 on the opposite side surface of the plate-type heat exchanger 30 with respect to the stacking direction 42. The inflow connection 49 and the outflow connection 51 of the cooling fluid chambers 44 have the common connection component 62, on which the expansion valve 28 is directly provided.

In each case a pipeline element of the secondary circuit 14 is connected to the inflow connection 53 and to the outflow connection 55 of the cooling fluid chambers 46.

FIG. 6 shows the flow profile of the coolant in the coolant chambers 44 and the profile of the cooling fluid in the cooling fluid chambers 46 of a first embodiment of the plate-type heat exchanger 30, and the temperature profile of the coolant and of the cooling fluid.

The coolant passes via the inflow 48 into the coolant chamber 44 which is formed by two adjacent heat exchanger plates 40. The coolant chamber 44 is in its entirety a U-shaped flow duct 64, wherein the inflow 48 of the coolant is arranged at the end of the first limb, and the outflow 50 is arranged at the end of the second limb, of the U-shaped flow duct 64. The two limbs of the U-shaped flow duct 64 are separated by an intermediate wall 66.

The “U” extends over approximately the entire length of the heat exchanger plates 40.

The cooling fluid chamber 46 is embodied as a U-shaped flow channel 68 for the cooling fluid, in the same way by an intermediate wall 66. The inflow 52 of the cooling fluid chamber 46 is arranged at the end of the first limb, and the outflow 54 is arranged at the end of the second limb, of the U-shaped flow duct 68 in the cooling fluid chamber 46. The U shape of the flow duct 68 for the cooling fluid is therefore inverted compared to the U-shaped flow duct 64 of the coolant, wherein the limbs of the two flow ducts 64, 68 rest one on the other.

In the embodiment according to FIG. 6, the directions of flow of the coolant and cooling fluid in adjoining coolant chambers 44 and cooling fluid chambers 46 in the two limbs are respectively opposed to one another.

FIG. 6 also shows the temperature profile in the first limb A from position A₁ to A₂, and in the second limb B from the position B₁ to B₂ in both chambers 44, 46. Given an inflow temperature of the cooling fluid at A₂ of 10° C. and an outflow temperature of the cooling fluid at B₁ of 4° C. as well as an inflow temperature of the coolant at A₁ of 4° C. and an outflow temperature of the coolant at B₂ of 1° C., an effective difference in temperature Δtlog of 5.1 K occurs in the limb A, an effective difference in temperature Δtlog of 3.6 K occurs in the limb B, and overall an average difference in the temperature Δtlog of 4.4 K respectively occurs between adjacent chambers 44, 46. The higher the difference in temperature between the coolant and the cooling fluid, the better the exchange of heat between the two.

FIG. 7 shows a second embodiment of the plate-type heat exchanger 30, wherein the design is essentially identical to the first embodiment. The second embodiment differs from the first in that the direction of flow in the coolant chamber 44 has been inverted. In the coolant chamber 44, the inflow 48 is therefore interchanged with the outflow 50 compared to the first embodiment.

The direction of flow in adjoining coolant chambers 44 and cooling fluid chambers 46 is therefore the same.

The coolant now firstly flows through the limb B of the U-shaped flow duct 64 from B₁ to B₂ and in the process cools from 4° C. to 2° C. The coolant subsequently flows through the limb A from A₁ to A₂, wherein it cools from 2° C. to 1° C. The saturation temperature is 0° C. As is apparent from the temperature profile diagrams, the difference in temperature in the limb A is greater than in the preceding embodiment, wherein the effective difference in temperature at Δtlog is 7 K. In the limb B, the difference in temperature is, in contrast, somewhat smaller and is 2.5 K at Δtlog. The average effective difference in temperature across the entire flow duct is 4.7 K at Δtlog. By making the directions of flow the same in adjoining coolant chambers 44 and cooling fluid chambers 46, an improved difference in temperature can be surprisingly achieved with the U-shaped flow ducts, as a result of which the effectiveness of the plate-type heat exchanger 30 is increased.

FIG. 8 shows a third embodiment of the plate-type heat exchanger 30. The direction of flow in the U-shaped flow ducts 64, 68 of the coolant chambers 44 and/or of the cooling fluid chambers 46 is identical to the second embodiment. The third embodiment differs from the second embodiment only in that the difference in pressure across the limb B of the U-shaped flow duct 64 for the coolant is between 70% and 100%, preferably between 80% and 92% of the overall difference in pressure, while the difference in pressure across the limb A is between 0% and 30%, preferably between 8% and 20% of the overall difference in pressure. In the limb B, the first limb in the direction of flow of the coolant, the coolant cools to a large degree and reaches 0.5° C. in the example shown. The cooling results from the static pressure which drops owing to the pressure loss, and owing to the resulting lowering of the coolant saturation temperature.

In contrast, no further cooling of the coolant takes place in the limb A since the saturation temperature only now drops at minimum by approximately 0.5 K due to the small pressure loss in the limb A. However, this drop in temperature has a superimposed coolant overheating of 1 K, with the result that the temperature at the coolant outlet A₂ of the limb A is even 0.5 K higher than at the inlet A₁. In this way, a very large difference in temperature is possible between the coolant chamber 44 and the cooling fluid chamber 46 in the region of limb A, wherein the effective difference in temperature at Δtlog is 7.6 K. In the limb B, the effective difference in temperature at Δtlog is 3.2 K. The average effective difference in temperature between the two limbs is 5.4 K at Δtlog, as a result of which a further improvement was achieved in the effectiveness of the plate-type heat exchanger 30.

The differences in pressure in the two limbs of the U-shaped flow duct 64 for the coolant can be achieved in various ways. In the example shown, the difference in pressure is achieved by a different flow resistance in the two limbs of the flow duct 64. For this purpose, different fin arrangements of the flow ducts or various inserts in the flow ducts are provided. Alternatively, the two limbs can also be embodied with a different flow cross section, by virtue of the fact that, for example, the intermediate wall 66 does not divide the two limbs of the U-shaped flow duct 64 uniformly.

FIG. 9 shows a fourth embodiment of the plate-type heat exchanger 30, wherein only the flow duct 64 for the coolant in the coolant chambers 44 is embodied in a U shape. The position of expansion valve 28 in the coolant chamber 44 is shown by dotted lines. The embodiment of the coolant chambers 44 and the direction of flow of the coolant through the U-shaped flow duct 64 is identical to the third embodiment of the plate-type heat exchanger 30. The fourth embodiment differs from the preceding embodiments in that the cooling fluid chambers 46 have a flow duct 70 which runs from the inflow 52 of the cooling fluid at the one end of the heat exchanger plates 40, parallel to the main extent direction 58 to an outflow 54 of the cooling fluid at the opposite end of the heat exchanger plates 40.

The difference in temperature diagrams at the top and bottom in FIG. 9 relate to the regions of the limbs A and B of the coolant chambers 44. The regions A and B are part of the same flow duct 70 through which there is a flow in one direction in the adjacent cooling fluid chambers 46. The temperature profile of the cooling fluid is therefore the same in both regions.

The temperature profile of the coolant corresponds to the temperature profile of the coolant in the third embodiment of the plate-type heat exchanger 30.

The effective difference in temperature in the limb A is 5.64 K at Δtlog, and the effective difference in temperature in the region of the limb B is 4.63 K at Δtlog.

In the embodiment shown in FIG. 9, the flow duct 70 of the cooling fluid chambers 46 does not need an intermediate wall 66. All that is therefore necessary is to provide an intermediate wall 66 in the coolant chambers 44. An intermediate wall 66 is therefore necessary only in every second chamber in the plate-type heat exchanger 30, which simplifies the design of the plate-type heat exchanger 30.

Various connection variants for connecting the plate-type heat exchanger 30 to the secondary circuit 14 are provided in the FIGS. 10, 11 and 12.

FIG. 10 shows a perspective view of the plate-type heat exchanger 30, wherein the expansion valve 28 is provided at the bottom on the left-hand side of the plate-type heat exchanger 30. Owing to the space requirement of the expansion valve 28, the outflow connection 55 for the cooling fluid is possible at the same end in the main extent direction 58 of the plate-type heat exchanger 30 only on the lateral surface, lying opposite the expansion valve 28, in the stacking direction 42. The inflow connection 53 which lies at the top in the main extent direction 58 can lie on the same lateral surface in the stacking direction 42 as the outflow connection 55, as is shown by a dotted line in FIG. 10, on the opposite lateral surface with respect to the stacking direction 42.

In the plate-type heat exchanger 30 which is shown in FIG. 11, an additional end plate 56 is provided on the lateral surface, lying opposite the expansion valve 28, of the plate-type heat exchanger 30 in the stacking direction 42. The end plate 56 forms a flow duct, indicated by the dotted line, for the cooling fluid, which flow duct connects the common outflow connection 55 of the heat exchanger plates 40 to a connection 72 for the cooling fluid system of the secondary circuit 12. In this way it is possible for the line systems of the secondary circuit 14 to each be provided at the same end in the main extent direction 58 of the plate-type heat exchanger 30, even though the common inflow and outflow connections 53, 55 of the cooling fluid chambers 46 lie at opposite ends of the plate-type heat exchanger 30 in the main extent direction 58.

FIG. 12 shows a similar embodiment, wherein the cooling fluid connections of the secondary circuit 14 lie on opposite sides of surfaces of the plate-type heat exchanger 30 in the stacking direction 42.

FIG. 13 in turn represents an embodiment of the plate-type heat exchanger 30, wherein the heat exchanger plates 40 are each of planar design and are spaced apart by wall elements 74 in order to form the coolant chambers 44 and the cooling fluid chambers 46. Further wall elements form the intermediate wall 66, which connects the adjacent heat exchanger plates 40.

FIG. 14 shows a further embodiment of the plate-type heat exchanger 30, wherein in each case two adjacent heat exchanger plates 40 have a shaped section 76, which shaped sections together form the intermediate wall 66 of the cooling fluid chambers 46. The intermediate wall 66 of the coolant chambers 44 is, in contrast, formed, in a way which is analogous to FIG. 13, by a wall element which connects the adjacent heat exchanger plates 40 to one another.

Inserts 78, which divide the coolant chambers 44 or cooling fluid chambers 46 into small parallel ducts which run along the limbs A and B in FIGS. 6 to 9, are provided in the coolant chambers 44 and the cooling fluid chambers 46 in FIGS. 13 and 14.

FIG. 15 shows a view of a detail of the plate-type heat exchanger 30 according to FIG. 2, wherein a throttle direction 80 is provided in the region of the connection component 62. In the embodiment shown in FIG. 15, the throttle device 80 is a pipe with calibrated diameter which projects from the connecting flange at least partially into one or more coolant chambers 44. A filter 82 is provided in front of the throttle device 80.

FIG. 16a illustrates an embodiment of a coolant distributor 81 of a simple design, wherein an opening which is relatively large compared to the throttle device 80 is provided at the common inflow connection 49 of the coolant chambers 44, which opening causes only part of the overall difference in pressure between the high pressure and low pressure; the rest of the difference in pressure is compensated by the expansion valve 28.

FIG. 16b shows an embodiment of the coolant distributor with a pipe with a calibrated diameter which extends into the common inflow connection 49 of the coolant chambers 44.

When the coolant exits the reduced opening 81 or the pipe with a calibrated diameter, the mixture of coolant phase is swirled, wherein homogenization of the mixture takes place and a more uniform distribution among the various coolant chambers 44 is made possible. In this way, a uniform cooling performance in all the coolant chambers 44 is achieved.

FIG. 16c shows a coolant distributor 81 in the form of a distributor insert which permits homogenous distribution of the coolant phase mixture among the various coolant chambers 44 of the plate-type heat exchanger 30.

Claims

1. A plate-type heat exchanger (30) for a vehicle for cooling a cooling fluid by means of a coolant, the heat exchanger (30) having a plurality of heat exchanger plates (40) which are stacked one on top of each other,

wherein coolant chambers (44) and cooling fluid chambers (46), which each have an inflow (48, 52) and an outflow (50, 54) for the coolant and/or the cooling fluid, are formed between adjacent heat exchanger plates (40), and

the coolant and/or cooling fluid chambers (44, 46) are embodied altogether as U-shaped flow ducts (64, 68), wherein the assigned inflow (48, 52) is arranged at the end of a first limb, and the assigned outflow (50, 54) is arranged at the end of a second limb, of the U-shaped flow duct.

2. A plate-type heat exchanger (30) according to claim 1, wherein the heat-exchanger plates (40) have, in the plane of their plates, both a main extent direction (58) and a secondary extent direction (60) running perpendicular thereto, and are arranged one next to the other in a stacking direction (42) which runs perpendicular to the main extent direction (58) and to the secondary extent direction (60), and wherein the inflow (48) and outflow (50) for the coolant are provided in the main extent direction (58), at the same end of the heat exchanger plates (40).

3. A plate-type heat exchanger (30) according to claim 2, comprising a common inflow connection (49) and outflow connection (51) for all the coolant chambers (44), wherein a connection component (62) is provided which permits direct attachment of an expansion valve (28) for the coolant to the plate-type heat exchanger (30).

4. A plate-type heat exchanger (30) according to claim 3, wherein the connection component (62) has a coolant distributor (81) which homogenizes distribution of the coolant phase mixture among different coolant chambers (44) of the plate-type heat exchanger (30).

5. A plate-type heat exchanger (30) according to claim 1, wherein the heat exchanger plates (40) have, in the plane of their plates, both a main extent direction (58) and a secondary extent direction (60) running perpendicular thereto, and are arranged one next to the other in a stacking direction (42) which runs perpendicular to the main extent direction (58) and to the secondary extent direction (60), and wherein the inflow (52) and outflow (52) (54) for the cooling fluid are provided in the main extent direction (58), at the same end or at opposite ends of the heat exchanger plates (40).

6. A plate-type heat exchanger (30) according to claim 1, comprising in each case a one common inflow connection (49) and a common outflow connection (51) for all the coolant chambers (44), and in each case a common inflow connection (53) and a common outflow connection (55) for all the cooling fluid chambers (46), wherein the common inflow connection (49) and outflow connection (51) for the coolant are arranged in the stacking direction (42) on the same lateral surface or on opposite lateral surfaces of the plate-type heat exchanger (30), as are the inflow connection (53) and outflow connection (55) for the cooling fluid.

7. A plate-type heat exchanger (30) according to claim 1, comprising a common inflow connection (53) and/or outflow connection (55) for all the cooling fluid chambers (46), wherein an end plate (56) is provided which is arranged in front of or behind the heat exchanger plates (40) in the stacking direction (42) and which forms at least one flow duct for the cooling fluid, the at least one flow duct connects the common inflow connection (53) and/or outflow connection (55) of the heat exchanger plates (40) to a connection (72) for a cooling fluid system.

8. A plate-type heat exchanger (30) according to claim 1, wherein the heat exchanger plates (40) have, in the plane of their plates, both a main extent direction (58) and a secondary extent direction (60) running perpendicular thereto, and are arranged one next to the other in a stacking direction (42) which runs perpendicular to the main extent direction (58) and to the secondary extent direction (60), and in that the inflow (48) and outflow (50) for the coolant are arranged in the main extent direction (58), at opposite ends of the heat exchanger plates (40), as are the inflow (52) and outflow (54) for the cooling fluid.

9. A plate-type heat exchanger (30) according to claim 8, wherein the directions of flow in adjoining coolant chambers (44) and cooling fluid chambers (46) are the same or opposed.

10. A plate-type heat exchanger (30) according to claim 1, wherein the heat exchanger plates (40) form a flow duct (70) in the cooling fluid chambers (46), and the flow duct (70) runs from an inflow (52) of the cooling fluid at one end of the heat exchanger plates (40) in the main extent direction (58) to an outflow (54) of the cooling fluid at the opposite end of the heat exchanger plates (40).

11. A plate-type heat exchanger (30) according to claim 1, wherein the difference of pressure across the first limb of the U-shaped flow duct (64) for the coolant is between 70% and 100% of the overall difference of pressure, and the difference of pressure across the second limb of the U-shaped flow duct (64) for the coolant in the direction of flow is between 0% and 30% of the overall difference of pressure.

12. A plate-type heat exchanger (30) according to claim 1, wherein the U-shape of the flow ducts (64, 68) is formed by an intermediate wall (66) which is formed by a part (74), which connects the adjacent heat exchanger plates (40), or by a shaped section (76) of at least one heat exchanger plate (40).

13. A plate-type heat exchanger (30) according to claim 1, wherein the limbs of the U-shaped flow ducts (64, 68) are formed by numerous elongated ducts arranged one next to the other.

14. An air-conditioning circuit (10) for a vehicle, the air-conditioning circuit (10) having a primary circuit (12) for a coolant and a secondary circuit (14) for a cooling fluid, wherein the primary circuit (12) and the secondary circuit (14) are coupled via the plate-type heat exchanger (30) according to claim 1.