Thermal management system and methods for operating a thermal management system

Abstract

The invention relates to a thermal management system (1) for a motor vehicle with a refrigerant circuit (2) comprising a refrigerant-coolant heat exchanger operating as a condenser / gas cooler (4-1) and a subcooler (4-3), as well as a high-temperature refrigerant circuit (6) with a coolant unit (7) and a conveying device (8). The high-temperature refrigerant circuit (6) is configured with a switching device such that the refrigerant circulating in the high-temperature refrigerant circuit (6) flows in the same direction through the condenser / gas cooler (4-1) and the subcooler (4-3) as at least two parallel partial mass flows. The flow directions of the refrigerant through the condenser / gas cooler (4-1) and the subcooler (4-3) are opposite to each other.The switching device of the high-temperature coolant circuit (6) is adjustable between two switching positions in order to direct the coolant as required. The invention also relates to methods for operating the thermal management system (1) for conditioning the supply air of a passenger compartment in different operating modes.

Description

[0001] The invention relates to a thermal management system for a motor vehicle with a refrigerant circuit and a high-temperature coolant circuit. The refrigerant circuit has a refrigerant-to-coolant heat exchanger operated as a condenser / gas cooler and a refrigerant-to-coolant heat exchanger operated as a subcooler, which are designed as components of the high-temperature coolant circuit, so that the refrigerant circuit and the high-temperature coolant circuit are thermally coupled to one another via the refrigerant-to-coolant heat exchangers. The invention also relates to methods for operating the thermal management system for a motor vehicle for conditioning the supply air of a passenger compartment in a refrigeration system mode, in particular for cooling and / or dehumidifying the supply air, and in a heating mode, specifically for heating the supply air of the passenger compartment.

[0002] Motor vehicles with various drive concepts are known from the state of the art. These concepts are based, for example, on drives powered by a fuel cell, an internal combustion engine, an electric motor, or a combination of both. Motor vehicles with a combination of internal combustion engine and electric motor drive therefore feature a hybrid drive, allowing the vehicle to be powered electrically, by an electric / combustion engine, or by a combustion engine, as needed.

[0003] Electric vehicles and hybrid vehicles, as well as fuel cell vehicles and highly energy-efficient combustion engine-powered vehicles, are known to not generate enough waste heat to heat the passenger compartment to meet thermal comfort requirements at low ambient temperatures.

[0004] In addition to the engine's waste heat, an air conditioning system with a heat pump function offers the option of heating the supply air to the passenger compartment in addition to operating in a refrigeration system mode. The air conditioning system utilizes various heat sources and heat sinks.

[0005] When the air conditioning system of a motor vehicle is operated in refrigeration mode to cool the supply air to the passenger compartment or a coolant circulating in a coolant circuit, in particular when operating a refrigerant circuit of the air conditioning system with an evaporator and a condenser / gas cooler of the refrigerant, the heat required to evaporate the refrigerant is absorbed at a low temperature and pressure level in the evaporator from the supply air to the passenger compartment or from a coolant circuit, also referred to as a low-temperature coolant circuit, each as a heat source. The coolant circuit can be used, for example, to cool components of the electric drive train, such as a traction battery, an internal charger, a transformer, an inverter, or a drive motor, of an electrically powered motor vehicle.The heat absorbed by the refrigerant, plus the power supplied by a compressor in the refrigerant circuit, can be transferred in the condenser / gas cooler at a higher temperature and pressure level to a heat sink, such as the ambient air or a coolant circuit, also known as a high-temperature coolant circuit.

[0006] When the air conditioning system, in particular the refrigerant circuit of the air conditioning system with heat pump function, is operated in a heating mode to heat the supply air for the passenger compartment, the heat required to evaporate the refrigerant is absorbed at the low temperature and pressure level in the evaporator from a heat source, such as the ambient air or the coolant circuit, specifically the low-temperature coolant circuit. In the condenser / gas cooler, the heat absorbed by the refrigerant plus the power supplied by the compressor of the refrigerant circuit can be released at a higher temperature and pressure level to a heat sink, specifically the supply air for the passenger compartment or the coolant circuit. The coolant circuit can be used, in particular, to heat components of the electric drive train of the electrically powered motor vehicle.

[0007] Depending on the operating mode of the air conditioning system, the heat can also be transferred from the coolant circulating in the coolant circuit, especially the high-temperature coolant circuit, to the supply air for the passenger compartment or from the supply air for the passenger compartment to the coolant circulating in the coolant circuit, especially the low-temperature coolant circuit, in order to heat or cool and / or dehumidify the supply air for the passenger compartment.

[0008] When the refrigerant is liquefied during subcritical operation of the refrigerant circuit, such as with the refrigerants R134a, R1234yf, R290, or R152a, or under certain ambient conditions with carbon dioxide, the heat exchanger is referred to as a condenser. Part of the heat transfer takes place at a constant temperature. During supercritical operation, or supercritical heat dissipation in the heat exchanger, the temperature of the refrigerant decreases continuously. In this case, the heat exchanger is also referred to as a gas cooler. Supercritical operation can occur under certain ambient conditions or operating modes of the refrigerant circuit, for example, with the refrigerant carbon dioxide.

[0009] DE 10 2021 113 104 A1 discloses a thermal management arrangement for a motor vehicle with a refrigerant circuit and two coolant circuits. The refrigerant circuit has at least one compressor, a condenser / gas cooler, an expansion element, and an evaporator. A first coolant circuit, also referred to as the coolant circuit, is thermally coupled to the refrigerant circuit via the evaporator, and a second coolant circuit, also referred to as the heat transfer circuit, is thermally coupled to the refrigerant circuit via the condenser / gas cooler.

[0010] Conventional systems with at least one refrigerant circuit and multiple coolant circuits feature a multitude of large-volume heat exchangers to meet all the system requirements regarding air conditioning of the passenger compartment and temperature control of various components, particularly electric drivetrains. As the various functions are fulfilled, the number of components that must be integrated into the vehicle also increases. The installation space of the vehicle is limited.

[0011] DE 10 2018 129 988 A1 discloses a compact heat exchanger unit for air conditioning systems in motor vehicles for liquid-cooled condensation of refrigerant in a refrigerant circuit, storage and subcooling of the liquid refrigerant, and evaporation of the refrigerant. Within a one-piece heat exchanger, in particular a plate heat exchanger, a condenser region, a high-pressure refrigerant collector region, a subcooling region, and an evaporator region for the refrigerant are combined, specifically each as plate packs.

[0012] In combined air conditioning systems for heating and cooling, especially the supply air to the passenger compartment of a motor vehicle, the conditions, particularly within the compact heat exchanger unit, vary greatly depending on the operating mode. For example, the subcooling of the refrigerant following condensation during operation of the air conditioning system in refrigeration mode should be within a maximum range of 8 K to 12 K. Higher subcooling leads to energy-inefficient operation of the air conditioning system. On the other hand, when the air conditioning system is operated in heating mode, higher subcooling of the refrigerant improves the energy efficiency of the air conditioning system. Other influencing factors are the required heat output and the temperature levels required for heat absorption by the refrigerant or for heat release from the refrigerant.

[0013] The liquid-cooled heat exchangers known from the prior art for condensing and subcooling the refrigerant are operated in parallel flow of refrigerant and coolant in the refrigerant subcooling zone. The parallel flow of the fluids results in less subcooling of the refrigerant at the heat exchanger outlet than, for example, if the fluids were flowing in countercurrent.

[0014] The object of the invention is to provide a thermal management system that is easy to assemble due to its low complexity and minimal number of components, and whose components are easy to replace, especially for repairs. The thermal management system should also have components that require minimal installation space. The heat transfer in the heat-transferring components of the refrigerant circuit and the coolant circuit should be maximized, and the temperature differences between the fluids achievable through heat transfer should be adaptable, especially when the thermal management system is operating in different modes.

[0015] The problem is solved by the subject matter having the features of the independent patent claims. Further developments are specified in the dependent patent claims.

[0016] The object is achieved by a thermal management system according to the invention for a motor vehicle with a refrigerant circuit and a high-temperature coolant circuit. The refrigerant circuit has a refrigerant-to-coolant heat exchanger operated as a condenser / gas cooler and a refrigerant-to-coolant heat exchanger operated as a subcooler for the refrigerant. The high-temperature coolant circuit is designed with a first coolant unit having a coolant reservoir and, if appropriate, coolant valves, as well as a first conveying device for conveying a coolant.

[0017] A thermal management system is an arrangement or device comprising multiple components and their control and regulating devices, which ensures the supply of heat or cold, in particular to a motor vehicle. The system is connected to various heat sources and heat sinks. For example, depending on requirements, heat can be transferred from the system to the ambient air, the supply air of the passenger compartment, or components of a powertrain, or heat can be transferred from the ambient air, the supply air of the passenger compartment, or components of the powertrain to the system. The heat absorbed by the system can be used, in particular at appropriate temperature levels, to heat the supply air of the passenger compartment or components of the powertrain. The heat can also be absorbed from the supply air of the passenger compartment or components of the powertrain.

[0018] The high-temperature coolant circuit is designed such that the coolant circulating in the high-temperature coolant circuit flows through the condenser / gas cooler and the subcooler as at least two parallel partial coolant mass flows in the same direction. The flow directions of the coolant through the condenser / gas cooler and the subcooler are oriented opposite to each other.

[0019] According to the concept of the invention, the high-temperature coolant circuit has a switching device for the flow direction of the coolant through the condenser / gas cooler and the subcooler, which is configured such that in a first switching position of the switching device the coolant flows in a countercurrent to the refrigerant through the condenser / gas cooler and in a cocurrent to the refrigerant through the subcooler, and in a second switching position of the switching device the coolant flows in a cocurrent to the refrigerant through the condenser / gas cooler and in a countercurrent to the refrigerant through the subcooler.

[0020] Depending on the switching position of the switching device, the refrigerant and the coolant partial mass flows can thus act on the condenser / gas cooler in a countercurrent flow and the subcooler in a cocurrent flow, and on the other hand, the condenser / gas cooler in a cocurrent flow and the subcooler in a countercurrent flow.

[0021] According to a further development of the invention, the condenser / gas cooler and the subcooler are combined within a heat exchanger unit. The heat exchanger unit has at least one first coolant connection and at least one second coolant connection, at which the condenser / gas cooler and the subcooler of the refrigerant circuit are integrated into the high-temperature coolant circuit.

[0022] According to an advantageous embodiment of the invention, the high-temperature coolant circuit has a valve arrangement as a switching device for the flow direction of the coolant, which is configured to guide the coolant in the first switching position from the conveying device to the first coolant connection of the heat exchanger unit, which is operated as an inlet, and from the second coolant connection of the heat exchanger unit, which is operated as an outlet, to the coolant unit, and to guide the coolant in the second switching position from the conveying device to the second coolant connection of the heat exchanger unit, which is operated as an inlet, and from the first coolant connection of the heat exchanger unit, which is operated as an outlet, to the coolant unit.

[0023] When the coolant partial mass flows flow in the same direction through the condenser / gas cooler and the subcooler, the coolant either flows into the heat exchanger unit, in particular the condenser / gas cooler and the subcooler, through the first coolant connection and out of the heat exchanger unit again through the second coolant connection, or the coolant flows into the heat exchanger unit, in particular the condenser / gas cooler and the subcooler, through the second coolant connection and out of the heat exchanger unit again through the first coolant connection.

[0024] According to a further development of the invention, the valve arrangement is designed as a 4 / 2-way valve with connections for integration into the high-temperature coolant circuit. A first connection serves as an inlet and is connected to the first conveying device via a connecting line; a second connection serves as an outlet and is connected to the first coolant unit via a connecting line; a third connection is connected to the first coolant connection of the heat exchanger unit via a connecting line; and a fourth connection is connected to the second coolant connection of the heat exchanger unit via a connecting line.

[0025] The valve arrangement is advantageously configured such that, in a first switching position, the first connection is internally connected to the third connection and the fourth connection is internally connected to the second connection. In a second switching position, the first connection is internally connected to the fourth connection and the third connection is internally connected to the second connection. Thus, in the first switching position, the first connection and the third connection, on the one hand, and the fourth connection and the second connection, on the other hand, are each switched to allow the coolant to pass through.

[0026] The condenser / gas cooler and the subcooler are preferably each configured as plate packs of a heat exchanger combined in a single-piece plate heat exchanger. The subcooler is arranged downstream of the condenser / gas cooler in the direction of refrigerant flow.

[0027] According to a preferred embodiment of the invention, the refrigerant circuit comprises a refrigerant-to-coolant heat exchanger operating as an evaporator. The evaporator can be integrated within the heat exchanger unit, so that the condenser / gas cooler, the subcooler, and the evaporator are preferably combined as plate packs in the one-piece plate heat exchanger. The evaporator is arranged downstream of the subcooler in the direction of refrigerant flow.

[0028] One advantage of the invention is that a low-temperature coolant circuit is provided, in particular with a second coolant unit and a second conveying device. The heat exchanger unit preferably has at least one third coolant connection and at least one fourth coolant connection, at which the evaporator of the coolant circuit is integrated into the low-temperature coolant circuit.

[0029] The refrigerant circuit can also be designed with a collector for the refrigerant and an internal heat exchanger.

[0030] An in-circuit heat exchanger is a heat exchanger that transfers heat from a high-pressure refrigerant to a low-pressure refrigerant. For example, the liquid refrigerant is further cooled after condensation or subcooling, and the suction gas of a compressor is superheated.

[0031] The collector for the refrigerant is located at the high pressure level in the refrigerant circuit.

[0032] The refrigerant collector and the in-circuit heat exchanger can each be integrated within the heat exchanger unit. The collector and the in-circuit heat exchanger can each be combined as a plate pack in the one-piece plate heat exchanger. Preferably, the refrigerant collector is arranged between the condenser / gas cooler and the subcooler in the direction of refrigerant flow, and the in-circuit heat exchanger is arranged between the subcooler and the evaporator in the direction of refrigerant flow.

[0033] According to a further preferred embodiment of the invention, the refrigerant circuit comprises an expansion element and a compressor. The expansion element, in particular an expansion valve, can be integrated within the heat exchanger unit.

[0034] The individual heat exchanger sections, in particular the condenser / gas cooler, subcooler, internal heat exchanger, evaporator, and the refrigerant collector, are advantageously thermally insulated from one another within the heat exchanger unit. At least one thermal insulation plate is arranged between each of the individual sections of the heat exchanger unit.

[0035] According to a further development of the invention, the high-temperature coolant circuit comprises at least one first coolant heat exchanger connected to the first coolant unit and the first conveying device via connecting lines. The first coolant heat exchanger can be designed to heat components of the motor vehicle's drivetrain or as a coolant-to-air heat exchanger for heating the supply air of the passenger compartment or for transferring heat to the ambient air.

[0036] According to an advantageous embodiment of the invention, the low-temperature coolant circuit has at least one second coolant heat exchanger connected to the second coolant unit and the second conveying device via connecting lines. The second coolant heat exchanger can be designed for cooling components of the motor vehicle's drive train or as a coolant-to-air heat exchanger for cooling and / or dehumidifying the supply air of the passenger compartment or for transferring heat from the ambient air.

[0037] The object is also achieved by methods according to the invention for operating a thermal management system for a motor vehicle.

[0038] A conceptual method for operating the thermal management system comprises the following steps when operating in a refrigeration system mode for conditioning the supply air of the passenger compartment, in particular for cooling and / or dehumidifying the supply air of the passenger compartment: - dividing a coolant circulating in a high-temperature coolant circuit into a first coolant partial mass flow and a second coolant partial mass flow, - guiding the first partial coolant mass flow through a condenser / gas cooler and the second partial coolant mass flow through a subcooler, wherein the partial coolant mass flows flow parallel to one another in the same direction through the condenser / gas cooler and the subcooler, - Mixing the coolant partial mass flows after flowing through the condenser / gas cooler and the subcooler and passing the coolant through a switching device to a first coolant unit, from which the coolant is sucked in by the first conveying device, and - passing a refrigerant circulating in the refrigerant circuit at a high-pressure level through the condenser / gas cooler in a countercurrent to the first partial coolant mass flow, whereby the refrigerant is deheated and condensed, and - Passing the refrigerant flowing out of the condenser / gas cooler through the subcooler in a cocurrent flow to the second partial coolant mass flow, whereby the refrigerant is subcooled or further cooled.

[0039] According to a further development of the invention, before being divided into partial coolant mass flows, the coolant is conveyed by a conveying device through a valve arrangement designed as a switching device to a first coolant connection of a heat exchanger unit, which is operated as an inlet. Before flowing through the heat exchanger unit, the coolant is divided into the first partial coolant mass flow and the second partial coolant mass flow. Furthermore, after the partial coolant mass flows have been mixed, the coolant is conveyed from a second coolant connection of the heat exchanger unit, which is operated as an outlet, through the valve arrangement to the coolant unit.

[0040] According to an advantageous embodiment of the invention, the valve arrangement is arranged in a first switching position such that the coolant is guided from the first connection, which is operated as an inlet and connected to the first conveying device via a connecting line, to the third connection, which is operated as an outlet and connected to the first coolant connection of the heat exchanger unit via a connecting line, and from the fourth connection, which is operated as an inlet and connected to the second coolant connection of the heat exchanger unit via a connecting line, to the second connection, which is operated as an outlet and connected to the first coolant unit via a connecting line.

[0041] A conceptual method for operating the thermal management system comprises the following steps when operating in a heating mode for conditioning the supply air of a passenger compartment, in particular for heating the supply air of the passenger compartment: - dividing a coolant circulating in a high-temperature coolant circuit into a first coolant partial mass flow and a second coolant partial mass flow, - guiding the first partial coolant mass flow through a condenser / gas cooler and the second partial coolant mass flow through a subcooler, wherein the partial coolant mass flows flow parallel to one another in the same direction through the condenser / gas cooler and the subcooler, - Mixing the coolant partial mass flows after flowing through the condenser / gas cooler and the subcooler and passing the coolant through a switching device to a first coolant unit, from which the coolant is sucked in by the first conveying device, and - passing a refrigerant circulating in the refrigerant circuit at a high-pressure level through the condenser / gas cooler in a cocurrent flow to the first partial coolant mass flow, whereby the refrigerant is deheated and condensed, and - Passing the refrigerant flowing out of the condenser / gas cooler through the subcooler in a counterflow to the second partial coolant mass flow, whereby the refrigerant is subcooled or further cooled.

[0042] A further advantage of the invention is that, before being divided into partial coolant mass flows, the coolant is conducted from a conveying device through a valve arrangement designed as a switching device to a second coolant connection of a heat exchanger unit, which is operated as an inlet. Before flowing through the heat exchanger unit, the coolant is divided into the first partial coolant mass flow and the second partial coolant mass flow. Furthermore, after the partial coolant mass flows have been mixed, the coolant is conducted from a first coolant connection of the heat exchanger unit, which is operated as an outlet, through the valve arrangement to the coolant unit.

[0043] According to a preferred embodiment of the invention, the valve arrangement is arranged in a second switching position such that the coolant is guided from the first connection, which is operated as an inlet and connected to the first conveying device via a connecting line, to the fourth connection, which is operated as an outlet and connected to the second coolant connection of the heat exchanger unit via a connecting line, and from the third connection, which is operated as an inlet and connected to the first coolant connection of the heat exchanger unit via a connecting line, to the second connection, which is operated as an outlet and connected to the first coolant unit via a connecting line.

[0044] By switching the flow direction of the coolant through the heat exchanger unit, in particular through the subcooler, between operation of the thermal management system in refrigeration mode and heating mode using the valve arrangement, the operation of the subcooler is changed from cocurrent between the refrigerant and the coolant to countercurrent between the refrigerant and the coolant. By changing the flow direction of the coolant, in particular through the subcooler, maximum heat transfer between the refrigerant and the coolant is achieved, with temperature differences between the refrigerant and the coolant that can be adjusted for different operating modes of the thermal management system. With the reversible flow direction of the coolant, the good heat transfer between two liquid fluids in the coolant-cooled and thus liquid-cooled subcooler is adapted for a given installed hardware.

[0045] Specifically, when the thermal management system is operating in heating mode to condition the supply air of a passenger compartment, and thus the counterflow of refrigerant and coolant within the subcooler, heat transfer between the refrigerant and coolant is maximized. This also increases the subcooling of the refrigerant at the subcooler outlet compared to when fluids are applied to the subcooler in cocurrent flow. This raises the condensation temperature and the high-pressure level of the refrigerant, thus increasing comfort in the passenger compartment. Switching the flow direction of the coolant in the condenser / gas cooler otherwise has no effect on the condensation process.

[0046] The thermal management system according to the invention also has a minimal number of components and low complexity, making it easy to install. System components are easy to replace. Due to the integral design of the components, the system also requires minimal installation space.

[0047] Further details, features and advantages of the invention will become apparent from the following description of an embodiment with reference to the accompanying drawings.

[0048] From the Fig. 1 and Fig. 2 shows a circuit diagram of a heat management system 1 with a refrigerant circuit 2, a high-temperature coolant circuit 6 and a low-temperature coolant circuit 11, which are thermally coupled to one another via refrigerant-coolant heat exchangers formed in a heat exchanger unit 4, during operation in a refrigeration system mode according to Fig. 1 and when operating in a heating mode according to Fig. 2. The operating modes are illustrated by arrows indicating the flow directions on the fluid-carrying connecting lines of the refrigerant circulating in the refrigerant circuit 2 and the coolant circulating in the coolant circuits 6, 11. The arrows and connecting lines, each marked with dashed lines, show the refrigerant at a high-pressure level (short dashed lines) and the refrigerant at a low-pressure level (long dashed lines).

[0049] The refrigerant circuit 2 comprises, in the direction of refrigerant flow, a compressor 3 and the heat exchanger unit 4 with a condenser / gas cooler 4-1, a receiver 4-2, a subcooler 4-3, an internal heat exchanger 4-4, and an evaporator 4-5. Furthermore, the refrigerant circuit 2 is designed with an expansion element 5, which is arranged between a high-pressure side of the internal heat exchanger 4-4 and the evaporator 4-5. The refrigerant flowing out of the evaporator 4-5 is guided to a low-pressure side of the internal heat exchanger 4-4. The refrigerant is drawn in by the compressor 3 from the low-pressure side of the internal heat exchanger 4-4. The refrigerant circuit 2 is closed.

[0050] The high-temperature coolant circuit 6 of the thermal management system 1 has a first coolant unit 7 with a coolant reservoir and, if appropriate, coolant valves, a first conveying device 8, and a valve arrangement 9. The valve arrangement 9 is designed as a 4 / 2-way valve with four ports 9-1, 9-2, 9-3, 9-4. A first port 9-1 of the valve arrangement 9 is connected to the first conveying device 8 via a connecting line and always serves as an inlet of the valve arrangement 9, while a second port 9-2 of the valve arrangement 9 is connected to the first coolant unit 7 via a connecting line and always serves as an outlet of the valve arrangement 9.A third port 9-3 and a fourth port 9-4 of the valve assembly 9 are each connected via a connecting line to a coolant port 4a, 4b of the heat exchanger unit 4 and are operated as an inlet or outlet for the coolant depending on a switching position of the valve assembly 9. The valve assembly can also be configured with multiple valves to fulfill the same function.

[0051] Within the high-temperature coolant circuit 6, the condenser / gas cooler 4-1 and the subcooler 4-3 of the heat exchanger unit 4 of the refrigerant circuit 2 are arranged such that the condenser / gas cooler 4-1 and the subcooler 4-3 can each be supplied with coolant in parallel. First coolant connections 4a of the heat exchanger unit 4, in particular of the condenser / gas cooler 4-1 and the subcooler 4-3, are connected via a connecting line to the third connection 9-3 of the valve arrangement 9, while second coolant connections 4b of the heat exchanger unit 4, in particular of the condenser / gas cooler 4-1 and the subcooler 4-3, are connected via a connecting line to the fourth connection 9-4 of the valve arrangement 9.

[0052] The refrigerant-coolant heat exchangers operated as condenser / gas cooler 4-1 or as subcooler 4-3 of the refrigerant each enable a transfer of heat from the refrigerant circulating in the refrigerant circuit 2 to the coolant circulating in the high-temperature coolant circuit 6, in particular a water-glycol mixture.

[0053] By means of the valve arrangement 9 designed as a 4 / 2-way valve, depending on the switching position, the first port 9-1 serving as the inlet can be connected to the third port 9-3 or the fourth port 9-4, so that the third port 9-3 or the fourth port 9-4 is operated as an outlet of the valve arrangement 9. Depending on the switching position, the second port 9-2 serving as the outlet is connected to the fourth port 9-4 or the third port 9-3, so that the fourth port 9-4 or the third port 9-3 is operated as an inlet of the valve arrangement 9.

[0054] The high-temperature coolant circuit 6 is also configured with at least one first coolant heat exchanger 10, which is connected to the first coolant unit 7 and the first conveying device 8 via connecting lines. The first coolant heat exchanger 10 is operated as a heat sink for the coolant circulating in the high-temperature coolant circuit 6 and thus for the refrigerant circulating in the refrigerant circuit 2. It can be used, for example, to heat the supply air of the passenger compartment, components of the motor vehicle's electric drive train, or to transfer heat to the ambient air.

[0055] The low-temperature coolant circuit 11 of the thermal management system 1 has a second coolant unit 12 with a coolant reservoir and, if appropriate, coolant valves, as well as a second conveying device 13. Also arranged within the low-temperature coolant circuit 11 is the evaporator 4-5 of the heat exchanger unit 4 of the refrigerant circuit 2. A third coolant connection 4c of the heat exchanger unit 4, operated as the inlet of the evaporator 4-5, is connected to the second conveying device 13, while a fourth coolant connection 4d of the heat exchanger unit 4, operated as the outlet of the evaporator 4-5, is connected to the second coolant unit 12.

[0056] The refrigerant-coolant heat exchanger, also referred to as chiller, operated as evaporator 4-5 of the refrigerant, enables a transfer of heat from the coolant circulating in the low-temperature coolant circuit 11, in particular a water-glycol mixture, to the refrigerant circulating in the refrigerant circuit 2.

[0057] Furthermore, the low-temperature coolant circuit 11 is configured with at least one second coolant heat exchanger 14, which is connected via connecting lines to the second coolant unit 12 and the second conveying device 13. The second coolant heat exchanger 14 is operated as a heat source for the coolant circulating in the low-temperature coolant circuit 11 and thus for the refrigerant circulating in the refrigerant circuit 2. It can be used, for example, to cool or dehumidify the air supplied to the passenger compartment, components of the motor vehicle's electric drive train, or to absorb heat from the ambient air.

[0058] The conveying devices 8, 13 of the coolant circuits 6, 11 are preferably each designed as a pump. The expansion element 5 of the refrigerant circuit 2 can be configured as an expansion valve.

[0059] The heat exchanger unit 4 is designed as a plate heat exchanger consisting of individual heat exchanger plates. In particular, the condenser / gas cooler 4-1, the subcooler 4-3, the in-circuit heat exchanger 4-4, and the evaporator 4-5 are combined from a plurality of plates, each connected to form a plate pack. The condenser / gas cooler 4-1 and the subcooler 4-3 are each designed as a liquid-cooled, in particular coolant-cooled, heat exchanger. The individual heat exchangers and the collector 4-2 are each separated from one another, in particular by means of insulation plates, in order to thermally insulate the heat exchanger areas operating at different temperature levels. Alternatively, the heat exchanger unit 4 can also be designed as individual components of the condenser / gas cooler 4-1, the subcooler 4-3, the in-circuit heat exchanger 4-4, and the evaporator 4-5.

[0060] In Fig. 1 shows the thermal management system 1 during operation in refrigeration system mode.

[0061] The refrigerant, compressed to a high-pressure level as it flows through the compressor 3, flows through a refrigerant inlet of the heat exchanger unit 4 into the condenser / gas cooler 4-1 and is guided in a countercurrent to the coolant circulating in the high-temperature coolant circuit 6, which flows into the condenser / gas cooler 4-1 as a first partial coolant mass flow through the first coolant connection 4a of the refrigerant-to-coolant heat exchanger, which is operated as an inlet. The refrigerant, liquefied as it flows through the condenser / gas cooler 4-1 by releasing heat to the coolant circulating in the high-temperature coolant circuit 6, is then guided to the collector 4-2, in which the liquid refrigerant is stored.

[0062] The refrigerant then flows from the collector 4-2 into the adjacent subcooler 4-3, where it is conducted in a cocurrent flow with the coolant circulating in the high-temperature coolant circuit 6. The coolant is introduced into the subcooler 4-3 as a second partial coolant mass flow, also through the first coolant connection 4a of the refrigerant-to-coolant heat exchanger, which is operated as an inlet, and thus parallel to the first partial coolant mass flow acting on the condenser / gas cooler 4-1.

[0063] The first and the second coolant partial mass flow of the high-temperature coolant circuit 6 can either be introduced into the heat exchanger unit 4 through a common first coolant connection 4a and divided within the heat exchanger unit 4 or each flow into the heat exchanger unit 4 through a first coolant connection 4a.

[0064] The first partial coolant mass flow flowing through the condenser / gas cooler 4-1 and the second partial coolant mass flow flowing through the subcooler 4-3 are discharged from the heat exchanger unit 4 in a heated state through the second coolant connection 4b, which is operated as an outlet. The first and second partial coolant mass flows can either be mixed with one another before flowing out of the heat exchanger unit 4 and flow out of the heat exchanger unit 4 together through a second coolant connection 4b, or they can each flow out of the heat exchanger unit 4 through a second coolant connection 4b and then be mixed with one another.

[0065] The liquid refrigerant, cooled as it flows through the subcooler 4-3 by releasing heat to the coolant circulating in the high-temperature coolant circuit 6, is then introduced into the circuit-internal heat exchanger 4-4 on the high-pressure side, where it flows countercurrently to the vaporous refrigerant flowing out of the evaporator 4-5 and introduced into the circuit-internal heat exchanger 4-4 on the low-pressure side. On the one hand, the liquid refrigerant is further cooled at the high-pressure level after subcooling, while on the other hand, the vaporous refrigerant is superheated at the low-pressure level as the suction gas of the compressor 3.

[0066] The liquid refrigerant cooled as it flows through the high pressure side of the internal heat exchanger 4-4 is expanded to the low pressure level as it flows through the expansion element 5 and is then introduced into the evaporator 4-5.

[0067] In the evaporator 4-5, the refrigerant flows in a countercurrent to the coolant circulating in the low-temperature coolant circuit 11, which flows into the evaporator 4-5 through the third coolant connection 4c of the refrigerant-to-coolant heat exchanger of the heat exchanger unit 4, which serves as an inlet. The refrigerant evaporates as it flows through the evaporator 4-5 by absorbing heat from the coolant of the low-temperature coolant circuit 11. The refrigerant, which evaporates as it flows through the evaporator 4-5 by absorbing heat from the coolant of the low-temperature coolant circuit 11, is then transferred on the low-pressure side to the internal heat exchanger 4-4, where the vaporous refrigerant is superheated. The superheated refrigerant is extracted from the internal heat exchanger 4-4 as suction gas by the compressor 3.

[0068] The coolant circulating in the low-temperature coolant circuit 11 is cooled and discharged from the evaporator 4-5 of the heat exchanger unit 4 through the fourth coolant connection 4d, which operates as an outlet, and is guided to the second coolant unit 12. The coolant stored in the coolant reservoir of the second coolant unit 12 is conveyed by the second conveying device 13, on the one hand, through the third coolant connection 4c of the heat exchanger unit 4 into the evaporator 4-5 of the refrigerant and, on the other hand, through the at least one second coolant heat exchanger 14. As it flows through the second coolant heat exchanger 14, the coolant is heated by absorbing heat from the supply air of the passenger compartment or from components of the drive train, in particular the electric one, of the motor vehicle. In the process, the supply air of the passenger compartment or the corresponding components of the drive train of the motor vehicle are cooled.

[0069] The coolant circulating in the high-temperature coolant circuit 6 is heated and discharged from the condenser / gas cooler 4-1 or the subcooler 4-3 of the heat exchanger unit 4 through the second coolant connection 4b, which is operated as an outlet, and is guided to the first coolant unit 7 via the valve arrangement 9. Internally, the fourth connection 9-4, which is operated as an inlet, and the second connection 9-2 of the valve arrangement 9 are connected to one another and connected as a passage.

[0070] The coolant stored in the coolant reservoir of the first coolant unit 7 is conveyed by the first conveying device 8, on the one hand, via the valve arrangement 9 to the first coolant connection 4a of the heat exchanger unit 4 and thus into the condenser / gas cooler 4-1 or the subcooler 4-3 of the heat exchanger unit 4, and on the other hand, through the at least one first coolant heat exchanger 10. Internally, the first connection 9-1 and the third connection 9-3 of the valve arrangement 9, which is operated as an outlet, are connected to one another and connected as a passage.

[0071] As it flows through the first coolant heat exchanger 10, the coolant is cooled by dissipating heat to components of the motor vehicle's drive train, in particular the electric drive train, or to the ambient air. In the process, the corresponding components of the motor vehicle's drive train may be heated.

[0072] In Fig. 2 shows the thermal management system 1 during operation in heating mode. The refrigerant circuit 2 and the low-temperature coolant circuit 11 are Fig. 1 and heating mode operate the same. The main difference between the operating modes of the thermal management system 1 in heating mode and refrigeration mode lies in the operation of the high-temperature coolant circuit 6, particularly in the switching position of the valve arrangement 9.

[0073] Internally, on the one hand, the first connection 9-1 and the fourth connection 9-4, which is operated as an outlet, and on the other hand, the third connection 9-3, which is operated as an inlet, and the second connection 9-2 of the valve arrangement 9 are connected to one another and each connected as a passage.

[0074] The refrigerant, compressed to the high-pressure level as it flows through the compressor 3, flows through the refrigerant inlet of the heat exchanger unit 4 into the condenser / gas cooler 4-1 and is conducted in a cocurrent flow to the coolant circulating in the high-temperature coolant circuit 6, which flows into the condenser / gas cooler 4-1 as a first partial coolant mass flow through the second coolant connection 4b of the refrigerant-coolant heat exchanger, which is operated as an inlet. The refrigerant, liquefied as it flows through the condenser / gas cooler 4-1 by releasing heat to the coolant circulating in the high-temperature coolant circuit 6, is subsequently conducted to the collector 4-2. The refrigerant then flows from the collector 4-2 into the adjacent subcooler 4-3, where it is conducted in a countercurrent flow to the coolant circulating in the high-temperature coolant circuit 6.The coolant is introduced as a second coolant partial mass flow into the subcooler 4-3 through the second coolant connection 4b of the refrigerant-coolant heat exchanger, which is operated as an inlet, and thus parallel to the first coolant partial mass flow acting on the condenser / gas cooler 4-1.

[0075] The first and the second coolant partial mass flow of the high-temperature coolant circuit 6 can either be introduced into the heat exchanger unit 4 through a common second coolant connection 4b and divided within the heat exchanger unit 4 or can each flow into the heat exchanger unit 4 through a second coolant connection 4b.

[0076] The first coolant partial mass flow flowing through the condenser / gas cooler 4-1 and the second coolant partial mass flow flowing through the subcooler 4-3 are discharged from the heat exchanger unit 4 in a heated state through the first coolant connection 4a, which is operated as an outlet. The first and second coolant partial mass flows can either be mixed with one another before flowing out of the heat exchanger unit 4 and flow out of the heat exchanger unit 4 together through a first coolant connection 4a, or they can each flow out of the heat exchanger unit 4 through a first coolant connection 4a and then be mixed with one another.

[0077] The coolant circulating in the high-temperature coolant circuit 6 is heated and discharged from the condenser / gas cooler 4-1 or the subcooler 4-3 of the heat exchanger unit 4 through the first coolant connection 4a, which is operated as an outlet, and is guided to the first coolant unit 7 via the valve arrangement 9.

[0078] The coolant stored in the coolant reservoir of the first coolant unit 7 is conveyed by means of the first conveying device 8, on the one hand, via the valve arrangement 9 to the second coolant connection 4b of the heat exchanger unit 4 and thus into the condenser / gas cooler 4-1 or the subcooler 4-3 of the heat exchanger unit 4 and, on the other hand, through the at least one first coolant heat exchanger 10.

[0079] As it flows through the first coolant heat exchanger 10, the coolant is cooled by releasing heat to the supply air of the passenger compartment or to components of the motor vehicle's electric drive train, in particular, while the supply air of the passenger compartment is heated. Corresponding components of the motor vehicle's drive train can also be heated.

[0080] The coolant circulating in the low-temperature coolant circuit 11 is heated as it flows through the second coolant heat exchanger 14 by absorbing heat from components of the motor vehicle's drive train, in particular the electric drive train, or from the ambient air. In the process, the corresponding components of the motor vehicle's drive train are cooled. LIST OF REFERENCE SYMBOLS 1 thermal management system 2 Refrigerant circuit 3 compressors 4 Heat exchanger unit 4-1 Condenser / Gas Cooler 4-2 collectors 4-3 subcoolers 4-4 internal heat exchanger 4-5 evaporators 4a first coolant connection heat exchanger unit 4 4b second coolant connection heat exchanger unit 4 4c third coolant connection heat exchanger unit 4 4d fourth coolant connection heat exchanger unit 4 5 Expansion organ 6 High-temperature coolant circuit 7 first coolant unit 8 first conveyor device 9 Valve arrangement 9-1 first connection 9-2 second connection 9-3 third connection 9-4 fourth connection 10 first coolant heat exchanger 11 Low-temperature coolant circuit 12 second coolant unit 13 second conveyor device 14 second coolant heat exchanger QUOTES CONTAINED IN THE DESCRIPTION

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

[0000] DE 10 2021 113 104 A1

[0009] DE 10 2018 129 988 A1

[0011]

Claims

[1] Thermal management system (1) for a motor vehicle, comprising a refrigerant circuit (2) with a refrigerant-coolant heat exchanger operated as a condenser / gas cooler (4-1) and a refrigerant-coolant heat exchanger operated as a subcooler (4-3), as well as a high-temperature coolant circuit (6) with a coolant unit (7) and a conveying device (8), wherein the high-temperature coolant circuit (6) is designed such that the coolant circulating in the high-temperature coolant circuit (6) flows through the condenser / gas cooler (4-1) and the subcooler (4-3) as at least two partial coolant mass flows guided parallel to one another, wherein the flow directions of the refrigerant through the condenser / gas cooler (4-1) and the subcooler (4-3) are oriented opposite to one another, characterized byin that the high-temperature coolant circuit (6) has a switching device for the flow direction of the coolant through the condenser / gas cooler (4-1) and the subcooler (4-3), which is configured such that, in a first switching position of the switching device, the coolant flows in a countercurrent to the refrigerant through the condenser / gas cooler (4-1) and in a cocurrent to the refrigerant through the subcooler (4-3), and in a second switching position of the switching device, the coolant flows in a cocurrent to the refrigerant through the condenser / gas cooler (4-1) and in a countercurrent to the refrigerant through the subcooler (4-3). [2] Thermal management system (1) according to claim 1, characterized byin that the condenser / gas cooler (4-1) and the subcooler (4-3) are combined within a heat exchanger unit (4), wherein the heat exchanger unit (4) has at least one first coolant connection (4a) and at least one second coolant connection (4b), at which the condenser / gas cooler (4-1) and the subcooler (4-3) of the refrigerant circuit (2) are integrated into the high-temperature coolant circuit (6). [3] Thermal management system (1) according to claim 2, characterized byin that the high-temperature coolant circuit (6) has a valve arrangement (9) as a switching device for the flow direction of the coolant, which is configured to guide the coolant in the first switching position from the conveying device (8) to the first coolant connection (4a) of the heat exchanger unit (4), which is operated as an inlet, and from the second coolant connection (4b) of the heat exchanger unit (4), which is operated as an outlet, to the coolant unit (7), and to guide the coolant in the second switching position from the conveying device (8) to the second coolant connection (4b) of the heat exchanger unit (4), which is operated as an inlet, and from the first coolant connection (4a) of the heat exchanger unit (4), which is operated as an outlet, to the coolant unit (7). [4] Thermal management system (1) according to claim 3, characterized byin that the valve arrangement (9) is designed as a 4 / 2-way valve with connections (9-1, 9-2, 9-3, 9-4) for integration into the high-temperature coolant circuit (6), wherein a first connection (9-1) is designed as an inlet via a connecting line to the conveying device (8), a second connection (9-2) is designed as an outlet via a connecting line to the coolant unit (7), a third connection (9-3) is connected via a connecting line to the first coolant connection (4a) of the heat exchanger unit (4), and a fourth connection (9-4) is connected via a connecting line to the second coolant connection (4b) of the heat exchanger unit (4). [5] Thermal management system (1) according to claim 4, characterized byin that the valve arrangement (9) is configured in such a way that, in a first switching position, the first connection (9-1) is connected to the third connection (9-3) and the fourth connection (9-4) is connected to the second connection (9-2) and, in a second switching position, the first connection (9-1) is connected to the fourth connection (9-4) and the third connection (9-3) is connected to the second connection (9-2). [6] Thermal management system (1) according to one of claims 2 to 5, characterized by that the condenser / gas cooler (4-1) and the subcooler (4-3) are designed as plate packs of a heat exchanger combined in a one-piece plate heat exchanger. [7] Thermal management system (1) according to one of claims 2 to 6, characterized by that the refrigerant circuit (2) has a refrigerant-coolant heat exchanger operated as an evaporator (4-5). [8] Thermal management system (1) according to claim 7, characterized bythat the evaporator (4-5) is integrated within the heat exchanger unit (4). [9] Thermal management system (1) according to claim 8, characterized by that the condenser / gas cooler (4-1), the subcooler (4-3) and the evaporator (4-5) are designed as plate packs combined in a one-piece plate heat exchanger. [10] Thermal management system (1) according to one of claims 7 to 9, characterized by that a low-temperature coolant circuit (11), in particular with a coolant unit (12) and a conveying device (13), is formed, wherein the heat exchanger unit (4) has at least one third coolant connection (4c) and at least one fourth coolant connection (4d), to which the evaporator (4-5) of the refrigerant circuit (2) is integrated into the low-temperature coolant circuit (11). [11] Thermal management system (1) according to one of claims 1 to 10, characterized bythat the refrigerant circuit (2) has a collector (4-2) and an internal circuit heat exchanger (4-4). [12] Thermal management system (1) according to claim 11, characterized by that the collector (4-2) and the internal circuit heat exchanger (4-4) are integrated within the heat exchanger unit (4). [13] Thermal management system (1) according to claim 12, characterized by that the collector (4-2) and the internal circuit heat exchanger (4-4) are designed as plate packs combined in a one-piece plate heat exchanger, wherein the collector (4-2) is arranged in the flow direction of the refrigerant between the condenser / gas cooler (4-1) and the subcooler (4-3) and the internal circuit heat exchanger (4-4) is arranged in the flow direction of the refrigerant between the subcooler (4-3) and an evaporator (4-5). [14] Thermal management system (1) according to one of claims 1 to 13, characterized byin that the high-temperature coolant circuit (6) has at least one first coolant heat exchanger (10) connected to the coolant unit (7) and the conveying device (8) via connecting lines, which first coolant heat exchanger is designed to heat components of a drive train of the motor vehicle or as a coolant-air heat exchanger for heating supply air of a passenger compartment or for transferring heat to ambient air. [15] Thermal management system (1) according to one of claims 10 to 14, characterized byin that the low-temperature coolant circuit (11) has at least one second coolant heat exchanger (14) connected to the coolant unit (12) and the conveying device (13) via connecting lines, which second coolant heat exchanger is designed for cooling components of a drive train of the motor vehicle or as a coolant-air heat exchanger for cooling and / or dehumidifying supply air of a passenger compartment or for transferring heat from ambient air. [16] Method for operating a thermal management system (1) for a motor vehicle in a refrigeration system mode for conditioning the supply air of a passenger compartment, in particular for cooling and / or dehumidifying the supply air of the passenger compartment, comprising the following steps: - dividing a coolant circulating in a high-temperature coolant circuit (6) into a first coolant partial mass flow and a second coolant partial mass flow, - guiding the first coolant partial mass flow through a condenser / gas cooler (4-1) and the second coolant partial mass flow through a subcooler (4-3), wherein the coolant partial mass flows flow parallel to one another in the same direction through the condenser / gas cooler (4-1) and the subcooler (4-3), - mixing the coolant partial mass flows after flowing through the condenser / gas cooler (4-1) and the subcooler (4-3) and passing the coolant through a switching device to a coolant unit (7), from which the coolant is sucked in by a conveying device (8), and - passing a refrigerant circulating in a refrigerant circuit (2) through the condenser / gas cooler (4-1) in a countercurrent to the first partial coolant mass flow, whereby the refrigerant is deheated and condensed, and - passing the refrigerant flowing out of the condenser / gas cooler (4-1) through the subcooler (4-3) in a cocurrent flow to the second partial coolant mass flow, whereby the refrigerant is subcooled. [17] Method according to claim 16 for operating the thermal management system (1) for a motor vehicle according to one of claims 3 to 15, characterized bythat the coolant, before being divided into partial coolant mass flows, is conducted from a conveying device (8) through a valve arrangement (9) designed as a switching device to a first coolant connection (4a) of a heat exchanger unit (4), which is operated as an inlet, and is divided into the first partial coolant mass flow and the second partial coolant mass flow before flowing through the heat exchanger unit (4), and that the coolant, after the mixing of the partial coolant mass flows, is conducted from a second coolant connection (4b) of the heat exchanger unit (4), which is operated as an outlet, through the valve arrangement (9) to a coolant unit (7). [18] Method according to claim 17, characterized bythat the valve arrangement (9) is arranged in a first switching position such that the coolant is guided from a first connection (9-1) operated as an inlet and connected to the conveying device (8) via a connecting line to a third connection (9-3) operated as an outlet and connected to the first coolant connection (4a) of the heat exchanger unit (4) via a connecting line, and from a fourth connection (9-4) operated as an inlet and connected to the second coolant connection (4b) of the heat exchanger unit (4) via a connecting line to a second connection (9-2) operated as an outlet and connected to a coolant unit (7) via a connecting line. [19] Method for operating a heat management system (1) for a motor vehicle in a heating mode for conditioning the supply air of a passenger compartment, in particular for heating the supply air of the passenger compartment, comprising the following steps: - dividing a coolant circulating in a high-temperature coolant circuit (6) into a first coolant partial mass flow and a second coolant partial mass flow, - guiding the first coolant partial mass flow through a condenser / gas cooler (4-1) and the second coolant partial mass flow through a subcooler (4-3), wherein the coolant partial mass flows flow parallel to one another in the same direction through the condenser / gas cooler (4-1) and the subcooler (4-3), - mixing the coolant partial mass flows after flowing through the condenser / gas cooler (4-1) and the subcooler (4-3) and passing the coolant through a switching device to a coolant unit (7), from which the coolant is sucked in by the conveying device (8), and - passing a refrigerant circulating in a refrigerant circuit (2) through the condenser / gas cooler (4-1) in a cocurrent flow to the first partial coolant mass flow, whereby the refrigerant is deheated and condensed, and - passing the refrigerant flowing out of the condenser / gas cooler (4-1) through the subcooler (4-3) in a counterflow to the second partial coolant mass flow, whereby the refrigerant is subcooled. [20] Method according to claim 19 for operating the thermal management system (1) for a motor vehicle according to one of claims 3 to 15, characterized bythat the coolant, before being divided into partial coolant mass flows, is conducted from a conveying device (8) through a valve arrangement (9) designed as a switching device to a second coolant connection (4b) of a heat exchanger unit (4), which is operated as an inlet, and is divided into the first partial coolant mass flow and the second partial coolant mass flow before flowing through the heat exchanger unit (4), and that the coolant, after the mixing of the partial coolant mass flows, is led from a first coolant connection (4a) of the heat exchanger unit (4), which is operated as an outlet, through the valve arrangement (9) to a coolant unit (7). [21] Method according to claim 20, characterized bythat the valve arrangement (9) is arranged in a second switching position such that the coolant is guided from a first connection (9-1) operated as an inlet and connected to the conveying device (8) via a connecting line to a fourth connection (9-4) operated as an outlet and connected to the second coolant connection (4b) of the heat exchanger unit (4) via a connecting line, and from a third connection (9-3) operated as an inlet and connected to the first coolant connection (4a) of the heat exchanger unit (4) via a connecting line to a second connection (9-2) operated as an outlet and connected to a coolant unit (7) via a connecting line.

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