Refrigeration system for a motor vehicle with a bypass line section for influencing the refrigerant temperature and method for influencing the refrigerant temperature as well as motor vehicle with such a refrigeration system

Abstract

A refrigeration system (10) for a motor vehicle (200) with an internal combustion engine and / or an electric drive is described, wherein the refrigeration system (10) comprises a refrigerant circuit (11) with a refrigerant compressor (12); a first heat exchanger (18), in particular a gas cooler or condenser; a second heat exchanger (22), in particular an evaporator; a refrigerant receiver (24); and a control unit (50). It is provided that the refrigerant circuit (11) has at least one bypass line section (30) which branches off downstream from the first heat exchanger (18) at a bypass branch (By1-By9) and terminates upstream of the refrigerant compressor (12) or at or in the refrigerant compressor (12).

Description

[0001] The invention relates to a refrigeration system for a motor vehicle with an internal combustion engine and / or an electric drive, wherein the refrigeration system has a refrigerant circuit with a refrigerant compressor; a first heat exchanger, in particular a gas cooler or condenser; a second heat exchanger, in particular an evaporator; a refrigerant receiver; and a control unit.

[0002] Refrigeration systems of this type, specifically designed to avoid critical refrigerant temperatures, are known. Reference is made in particular to DE 10 2020 117 816 A1, DE 197 43 629 A1 and US 2007 221 371 A.

[0003] In refrigeration systems, the hot gas temperature of the refrigerant (refrigerant temperature after compression) is generally dependent on the inlet temperature of the refrigerant at the compressor and on the efficiency of the compressor. Therefore, components of the refrigeration system, such as heat exchangers, must be limited in their design, which can lead to losses in performance or efficiency during refrigeration system operation. This can result, for example, in a lower vapor content in the refrigerant receiver or a reduction in the heat exchange efficiency of the internal heat exchanger.

[0004] The object underlying the invention is seen as being to provide a refrigeration system in which the above disadvantages can be avoided, in particular a limitation of the design of components of the refrigeration system is not necessary.

[0005] This problem is solved by a refrigeration system, a method, and a motor vehicle with the features of the respective independent patent claim. Advantageous embodiments with expedient further developments are specified in the dependent patent claims.

[0006] A refrigeration system, optionally capable of incorporating heat pump functionality, is proposed for a motor vehicle with an internal combustion engine and / or an electric drive. The refrigeration system comprises a refrigerant circuit with a refrigerant compressor; a first heat exchanger, in particular a gas cooler or condenser; a second heat exchanger, in particular an evaporator; a refrigerant receiver; and a control unit. The refrigerant circuit includes at least one bypass section that branches off downstream from the first heat exchanger at a bypass branch and terminates upstream at or within the refrigerant compressor.

[0007] Such a bypass line section makes it possible to supply additional refrigerant to the inlet side of the refrigerant compressor, thus influencing, and in particular lowering, the inlet refrigerant temperature so that a non-critical refrigerant temperature is reached after compression. The bypass line section also allows for post-evaporation of the supplied, vaporous refrigerant on the low-pressure side of the refrigerant compressor, resulting in the desired effect of a reduced refrigerant temperature after compression.

[0008] The refrigeration system may have an internal heat exchanger, wherein the bypass line section bypasses the internal heat exchanger, branches off upstream of the internal heat exchanger on the low-pressure side, and terminates upstream of the refrigerant compressor or at or in the refrigerant compressor.

[0009] In a refrigeration system, the bypass line section can be equipped with a fixed throttling device. Alternatively, the bypass line section can be designed as a capillary tube. In both cases, this ensures a continuous refrigerant flow through the bypass line section. This allows for a simple and essentially unaffected and constant reduction in the inlet refrigerant temperature.

[0010] In the refrigeration system, the bypass line section may have an adjustable valve device designed to allow or block an adjustable flow of refrigerant through the bypass line section.

[0011] In this context, the control unit can be configured to control the adjustable valve device depending on a refrigerant temperature detected at the outlet of the refrigerant compressor, in particular to open or close it at least partially or stepwise.

[0012] This allows at least one bypass line section with its adjustable valve device to be used selectively or depending on the refrigeration system operation, so that a reduction of the inlet refrigerant temperature at the refrigerant compressor can only occur as needed, and thus be increased at high load operating points and reduced or not at all in medium or low load operating situations.

[0013] In a refrigeration system, the bypass branch can be located on the high-pressure or low-pressure side of the refrigerant circuit. If the bypass branch is located on the high-pressure side, particularly upstream of the second heat exchanger (evaporator) and also downstream of an expansion device associated with the second heat exchanger, the adjustable valve assembly in the bypass line section can be designed as an expansion valve.

[0014] In a refrigeration system, the bypass branch can be arranged at the refrigerant receiver in such a way that a substantially liquid phase of the refrigerant is routed through the bypass line section. This liquid phase is then re-evaporated at the inlet side of the refrigerant compressor.

[0015] It is generally noted that the refrigeration system can have a single bypass line section, but also two or more such bypass line sections. For example, it is conceivable to provide bypass branches at two or three points in the refrigerant circuit, each with its own bypass line section, which then terminates upstream of or at the refrigerant compressor. Furthermore, it is also conceivable that several bypass line sections are first joined upstream of the refrigerant compressor before a connection is made upstream of, to, or into the refrigerant compressor.

[0016] A method for influencing the refrigerant temperature in a refrigeration system described above, with an adjustable valve in the bypass line section, is also proposed. This method includes, in particular, the following steps: Measuring the refrigerant temperature at the outlet or downstream of the refrigerant compressor; Comparing the measured refrigerant temperature with a limit value; at least partially opening or keeping open the valve device in the bypass line section when the limit value is reached or exceeded; At least partially closing or keeping closed the valve device in the bypass line section when the limit value is undershot.

[0017] Furthermore, a motor vehicle with an internal combustion engine and / or an electric drive and with a refrigeration system as described above is proposed.

[0018] Further advantages and details of the invention will become apparent from the following description of embodiments with reference to the figures. These show: Fig. 1. A simplified and schematic representation of an example of a refrigeration system in a motor vehicle; Fig. 2. A simplified and schematic representation of a method for influencing a refrigerant temperature in the refrigeration system of the Fig. 1.

[0019] In Fig. Figure 1 is a simplified and schematic example of a refrigeration system 10 with a refrigerant circuit 11. The refrigeration system 10 is shown here in a motor vehicle 200, which is schematically illustrated as a rectangle.

[0020] The refrigeration system 10 comprises, in the refrigerant circuit 11, a refrigerant compressor 12, a first (external) heat exchanger 18, in particular a gas cooler or condenser, and a second heat exchanger 22, in particular an (indoor) evaporator. A low-pressure refrigerant receiver 24 is arranged in the refrigerant circuit 11. Furthermore, the refrigerant circuit 11 includes an internal heat exchanger 20.

[0021] The terms pT1, pT2, and pT3 are examples of sensor devices. These sensor devices can, in particular, detect or measure the refrigerant temperature and / or refrigerant pressure in the refrigerant circuit 11.

[0022] The refrigeration system also has a control unit 50, which is designed to adjust the components of the refrigeration system 10, such as the refrigerant compressor 12 or an expansion valve AE1 upstream of the evaporator 22.

[0023] By way of example only, the refrigerant circuit 11 includes a further (third) heat exchanger 26, in particular a chiller, which is in thermal contact with a coolant circuit of the motor vehicle not shown here, wherein the coolant circuit is in particular designed to cool, for example, power electronics and / or a high-voltage battery of the motor vehicle 200.

[0024] The refrigerant circuit 11 has at least one bypass line section 30 that bypasses the internal heat exchanger 20. In the Fig. Figure 1 shows various examples of bypass line sections 30 as dashed lines. At least one bypass line section 30 branches off downstream from the first heat exchanger 18 and upstream on the low-pressure side from the inner heat exchanger 20 at a respective bypass branch Byn (with n = 1 to 9; circle with a single cross). The bypass line section 30 terminates upstream of, at, or within the refrigerant compressor 12, as illustrated by the connections An1, An2, and An3 (circle with crossed hatching).

[0025] The bypass line section 30, which extends from the bypass branch By7 to the connection An2, is shown as an example where the bypass line section 30 is equipped with a fixed throttling device 32. Alternatively, this can also serve as an illustration that the bypass line section 30 is designed as a capillary line. In both cases, a continuous refrigerant flow is provided through such a bypass line section 30.

[0026] The bypass line section 30 can have an adjustable valve assembly 34, which is configured to allow or block a refrigerant flow through the bypass line section 30 as required. An example of such an adjustable valve assembly 34 is illustrated in the bypass line section 30 from By3 to An1 and in the bypass line section 30 from By9 to An2.

[0027] The bypass line sections 30, which extend between By3 and An1, By7 and An2 as well as By9 and An2, have their respective bypass branch By3, By7 and By9 on the low-pressure side in the refrigerant circuit 11.

[0028] A bypass branch By1 or By2 can also be arranged on the high-pressure side of the refrigerant circuit. In the high-pressure branch of the bypass line section 30 from By1 to An1, the adjustable valve assembly is designed as an expansion valve 34e, so that the refrigerant can be expanded towards the low-pressure side.

[0029] Another possibility is to arrange the bypass branch By8 at the refrigerant collector 24 in such a way that an essentially liquid phase of the refrigerant is routed through a corresponding bypass line section, which, however, for the sake of clarity, is located in the Fig. 1 is not shown again.

[0030] In the Fig. Figure 1 illustrates various positions of bypass branches By1 to By9, whereby only one such bypass branch can be present in the refrigerant circuit 11, at one of the positions shown as examples. Furthermore, it is noted that in the Fig. 1. Not all possible bypass line sections 30 between bypass branches By1 to By9 and the connections An1, An2 are shown. Further or different routes of bypass line sections 30 not shown can easily be imagined without needing to be explicitly depicted.

[0031] In Fig. Figure 2 shows a simplified and schematic method 500 for influencing a refrigerant temperature in a refrigeration system 10 described above, wherein the method 500 comprises the following steps.

[0032] According to step S501, a refrigerant temperature is measured at the outlet or downstream of the refrigerant compressor 12, for example by means of the sensor device pT1.

[0033] According to step S502, the recorded refrigerant temperature is compared with a limit value.

[0034] According to step S503, the valve device 34 in the bypass line section 30 is partially opened or kept open when the limit value is reached or exceeded.

[0035] According to step S504, the valve device 34 in the bypass line section 30 is at least partially closed or kept closed if the limit value is undershot.

[0036] The procedure can be repeated, as illustrated by the connecting line from steps S503, S504 to step S501.

[0037] It is noted that method 500 can be implemented such that one or more adjustable valve devices 34 are adjustable in one or more (respective) bypass line sections 30. If, for example, two bypass line sections 30 are implemented with a respective valve device 34, method 500 can be designed or extended so that it can also be decided whether one or both bypass line sections are activated or deactivated by (partially) opening / closing the respective valve device.

[0038] For the sketched refrigeration system 10 with a refrigerant circuit 11, a relatively simple system configuration has been chosen. The design of such a refrigerant circuit 11 can be arbitrarily complex, even incorporating heat pump functionality. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2020 117 816 A1

[0002] DE 197 43 629 A1

[0002] US 2007 221 371 A

[0002]

Claims

[1] Refrigeration system (10) for a motor vehicle (200) with an internal combustion engine and / or an electric drive, wherein the refrigeration system (10) has a refrigerant circuit (11) with a refrigerant compressor (12); a first heat exchanger (18), in particular a gas cooler or condenser; a second heat exchanger (22), in particular an evaporator, and a refrigerant collector (24); a control unit (50); characterized by , that the refrigerant circuit (11) has at least one bypass line section (30) which branches off downstream from the first heat exchanger (18) at a bypass branch (By1-By9) and terminates upstream from the refrigerant compressor (12) or at or in the refrigerant compressor (12). [2] Refrigeration system according to claim 1, characterized by, that it has an internal heat exchanger (20), wherein the bypass line section (30) bypasses the internal heat exchanger, branches off upstream from the internal heat exchanger (20) and terminates upstream of the refrigerant compressor (12) or at or in the refrigerant compressor (12). [3] Refrigeration system (10) according to claim 1 or 2, characterized by that the bypass line section (30) is designed with a fixed throttling device (32) or that the bypass line section (30) is designed as a capillary line, so that a continuous refrigerant flow is provided through the bypass line section (30). [4] Refrigeration system (10) according to claim 1, characterized by , that the bypass line section (30) has an adjustable valve device (34) which is configured to allow or block an adjustable refrigerant flow through the bypass line section (30). [5] Refrigeration system (10) according to claim 4, characterized by, that the control unit (50) is configured to control the adjustable valve assembly (34) depending on a refrigerant temperature detected at the outlet of the refrigerant compressor (12), in particular to open or close it at least partially or stepwise. [6] Refrigeration system (10) according to any of the preceding claims, characterized by that the bypass branch (By1-By9) is arranged on the high-pressure side or low-pressure side of the refrigerant circuit (11). [7] Refrigeration system (10) according to any of the preceding claims, characterized by , that the bypass branch (By8) is arranged on the refrigerant collector (24) such that an essentially liquid phase of the refrigerant is passed through the bypass line section (30). [8] Method (500) for influencing a refrigerant temperature in a refrigeration system (10) according to any one of claims 4 to 7, wherein the method (500) comprises the following steps: Measuring (S501) a refrigerant temperature at the outlet or downstream of the refrigerant compressor (12); (S502) Compare (S502) the recorded refrigerant temperature with a limit value; At least partially opening (S503) or keeping open the valve device (34) in the bypass line section (30) when the limit value is reached or exceeded; At least partial closing (S504) or keeping closed of the valve device (34) in the bypass line section (34) when the limit value is undershot. [9] Motor vehicle (200) with an internal combustion engine and / or an electric drive and with a refrigeration system (10) according to any one of claims 1 to 7.

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