THERMAL MANAGEMENT SYSTEM FOR A VEHICLE

Abstract

Thermal management system (10) for a vehicle, comprising: - a vehicle air conditioning system (20) with: - an air inlet (21), - an arrangement of air outlets (22) communicating with a compartment (15) to be air-conditioned, and - a first air duct (24) which conveys air from the air inlet (21) to the arrangement of air outlets (22) by means of a fan (23), - a refrigerant circuit (30) with: - a compressor (31), - a first expansion valve arrangement (32), - a first heat exchanger (33; 102) which is connected in the high-pressure section downstream of the compressor (31) and upstream of the first expansion valve arrangement (32), - a low-pressure heat exchanger arrangement (34; 35) which is connected in the low-pressure section downstream of the first expansion valve arrangement (32) and upstream of the compressor (31), and - a second heat exchanger (36) which is adapted to be operated in thermal exchange in an exhaust air flow (51) with the outside environment and to be switchable into the high-pressure section in cooling mode and into the low-pressure section in heating mode, and - a control unit (60) for controlling the operation of the thermal management system (10), wherein - the first heat exchanger (33; 102) connected in the high-pressure section is used to heat the air conveyed into the compartment (15) to be air-conditioned and is arranged either in the first air duct (24) or as an indirect heater (102) which transfers the heat via a coolant loop (101) to a coolant-air heat exchanger (103) arranged in the first air duct (24), and - downstream of the first heat exchanger (33) or the coolant-air heat exchanger (103), the first air duct (24) has an openable and closable second air duct (25) which branches off into an area outside the compartment (15) to be air-conditioned, characterized in that - an openable and closable radiator grille closure (50) is arranged upstream of the second heat exchanger (36) and upstream of an optional coolant radiator (43) in the air flow direction of the exhaust air flow (51), which is coupled to the second air duct (25) in such a way that at least one of the radiator grille closure (50) and / or the second air duct (25) is open.

Description

[0001] The present invention relates to a thermal management system for a vehicle and a method for operating such a system for providing a situation-dependent cooling function. Such systems are particularly applicable to, but not limited to, electric vehicles.

[0002] Thermal management systems for vehicles are known as such in many configurations. They typically include units such as a vehicle air conditioning system, a refrigerant circuit, a coolant circuit, and a control unit. The control unit communicates with various units of the thermal management system and is adapted to control its operation. The main idea of ​​thermal management is to balance thermal energy between the immediate environment, the air conditioning system, the refrigerant circuit, and various electrical components of the powertrain that are in thermal contact with the coolant circuit.

[0003] For this purpose, the vehicle air conditioning system comprises at least one air inlet, an arrangement of air outlets in communication with a compartment to be air-conditioned (typically the passenger cabin), and a first air duct which, by means of a fan, conveys air from the air inlet to the arrangement of air outlets. As such, the air conditioning system can be of any type known from the prior art and typically comprises means for cooling and heating in the at least one air duct. The refrigerant circuit comprises a compressor and a first expansion valve, wherein a high-pressure section is formed downstream of the compressor and upstream of the first expansion valve, and a low-pressure section is formed downstream of the first expansion valve and upstream of the compressor.A first heat exchanger is connected in the high-pressure section, and a second heat exchanger ("outdoor heat exchanger") is adapted to operate in thermal exchange with the outside environment in an exhaust air stream and can be switched to the high-pressure section in cooling mode and to the low-pressure section in heating mode. Furthermore, a low-pressure heat exchanger arrangement is connected in the low-pressure section.

[0004] The first heat exchanger is typically used to heat the air fed into the compartment to be air-conditioned. For this purpose, the first heat exchanger can be designed as an internal condenser or internal gas cooler and arranged in the at least one air duct - or as an indirect heater, e.g., by transferring heat via a coolant loop to a coolant-to-air heat exchanger. The high-pressure section can have different pressure stages, e.g., with pressure drops or pressure stages from the compressor outlet to the first expansion valve, i.e., it consists of one or more intermediate pressure levels that are also adapted to transfer heat from the refrigerant circuit to the heat exchange partner (no heat absorption into the system).

[0005] The thermal management system may typically further comprise a coolant circuit having at least one pump, a first coolant branch having a coolant radiator adapted to operate in the exhaust air flow in thermal exchange with the outside environment, a second coolant branch in thermal exchange with components of the vehicle drivetrain, and a third coolant branch in thermal exchange with the low-pressure heat exchanger arrangement.

[0006] The low-pressure heat exchanger arrangement can typically comprise a third and a fourth heat exchanger. The third heat exchanger is typically configured as an evaporator arranged in at least the first air duct to cool and dehumidify the air for the compartment to be air-conditioned. Alternatively, the heat can be transferred to the first air duct indirectly using a coolant loop and an additional heat exchanger. The fourth heat exchanger is in thermal contact with a coolant branch of the coolant circuit and is often referred to as a chiller.

[0007] The first heat exchanger is typically located in the first air duct downstream of the third heat exchanger. With the fourth heat exchanger typically parallel to the third heat exchanger in the low-pressure section of the refrigerant circuit, in thermal contact with the coolant circuit, the cooling capacity can be balanced between the vehicle's engine and the air to the compartment to be air-conditioned.

[0008] The cooling capacity of the vehicle's thermal management system is limited by the available space and the size of the vehicle's front end. The size of the second heat exchanger (the "exterior heat exchanger") and the coolant radiator are limited by the size of the vehicle's front end. Furthermore, the coolant radiator typically needs to be positioned upstream of the exterior heat exchanger in the airflow to effectively cool the vehicle's powertrain. These structural limitations impact cooling capacity.

[0009] A thermal management system for a vehicle with a vehicle air conditioning system and a refrigerant circuit, as well as methods for operating such a thermal management system, are known, for example, from FR 3 049 237 A1. JP 2013-107 612 A and US 2023 / 0 040 086 A1 disclose further thermal management systems for vehicles and corresponding methods for operating them.

[0010] It is an object of the present invention to provide a thermal management system and a method for operating such a system which enables an energy-efficient and flexible provision of a cooling function in a situation-dependent manner while mitigating the above-mentioned limitations.

[0011] The problem is solved by a thermal management system having the features of the main claim and by a method for operating such a thermal management system having the features of the dependent claim 7. Advantageous embodiments and further developments are the subject of the dependent claims.

[0012] The thermal management system according to the present disclosure comprises a first heat exchanger (for heating air to the compartment to be air-conditioned), which is either arranged in the first air duct or configured as an indirect heater that transfers the heat via a coolant loop to a coolant-to-air heat exchanger arranged in the first air duct. Downstream of the first heat exchanger, the first air duct has an openable and closable second air duct, which branches off into an area outside the compartment to be air-conditioned. Such areas can typically be the exterior environment of the vehicle, such as an area on the floor of the vehicle. This air bypass has the advantage that the first heat exchanger does not have to be bypassed on the refrigerant side, because the heat is dissipated to an exterior area of ​​the vehicle cabin. This allows for a simplification of the layout of the refrigerant circuit.

[0013] According to one aspect of the present disclosure, an openable and closable bypass is formed around the third heat exchanger to supply air from the air inlet to the first heat exchanger without passing through the third heat exchanger. This bypass can be opened at times of increased cooling demand, so that the portion of cooled air (which has passed through the third heat exchanger) is used for air conditioning, and the portion of bypassed air (which has passed through the first heat exchanger) can be discharged via the second air duct branching outward.

[0014] According to another aspect of the present disclosure, the first heat exchanger is arranged downstream of the third heat exchanger within the first air duct such that condensate formed at the third heat exchanger is directed to the first heat exchanger to provide evaporative cooling. This can be used to further increase cooling capacity. The first heat exchanger can be positioned at a lower level in the downstream airflow than the third heat exchanger to utilize gravity and airflow. The arrangement can further include guide channels for directing condensate to the face of the first heat exchanger.

[0015] According to yet another aspect of the present disclosure, the coolant radiator is arranged downstream of—i.e., behind—the second heat exchanger in the exhaust air flow. Heat dissipation through the branching second air duct to the outside environment can reduce heat dissipation in the second heat exchanger (the outside heat exchanger). Due to this reduced heat dissipation, the coolant radiator can be effectively operated behind—i.e., downstream of—the second heat exchanger in the air flow.

[0016] Due to the heat dissipation through the second air duct, heat dissipation through the second heat exchanger may no longer be required if the cooling requirement falls below a specific limit. If this is the case, the second heat exchanger can be deactivated. The second heat exchanger can be deactivated on the refrigerant side, e.g., by means of a valve arrangement, or on the air side. For this purpose, an openable and closable radiator grille closure is arranged upstream of the second heat exchanger and upstream of the coolant radiator in the airflow direction. The opening and closing action of the radiator grille closure is coupled to the second air duct such that at least one of the radiator grille closure and / or the second air duct is open. The coupling can be controlled, in particular, by control logic running in the control unit.

[0017] The thermal management system disclosed here can be applied to any refrigerant. It is particularly applicable to R744 (CO2) for maximum cooling in hot countries. Instead of isolating the first heat exchanger (i.e., the internal gas cooler in R744 refrigerant circuits), the second heat exchanger (i.e., the external heat exchanger) is isolated from the refrigerant flow.

[0018] According to the present invention, a method for operating such a thermal management system as described above is disclosed, characterized in that the thermal management system is operated in a first operating mode, wherein the second air duct is closed, and the thermal management system is operated in a second operating mode, which is a cooling mode, wherein the second air duct is open to allow the dissipation of thermal energy from the vehicle air conditioning system. The decision to operate the system in the first or second operating mode can be made simultaneously, e.g., at start-up. Alternatively, it can be made sequentially, such that the system is started in the first operating mode as a default and is switched to the second operating mode based on a trigger.Optionally, the fan speed is adjusted when the system is switched to the second operating mode to maintain the required airflow through the evaporator and into the cabin to be conditioned (due to airflow losses through the open second air duct). In typical applications, both the first operating mode and the second operating mode are cooling modes, with the first heat exchanger and the second heat exchanger operating in the high-pressure section of the refrigerant circuit.

[0019] Cooling modes can also include partial reheating of the air cooled by the evaporator (reheat mode), as long as the second heat exchanger is operating in the high-pressure section of the refrigerant circuit. Depending on the cooling demand, greater cooling capacity can be achieved by expelling hot air to the exterior of the vehicle. The trigger for switching to the second operating mode can therefore depend on the cooling demand, which typically depends on the ambient temperature.

[0020] According to one embodiment of the present disclosure, in the second operating mode, the bypass around the third heat exchanger is opened and the speed of the fan is increased. Alternatively or additionally, in the second operating mode, the second heat exchanger can be deactivated and the bypass around the third heat exchanger can optionally be closed (or remain closed). The deactivation of the second heat exchanger can be achieved by shutting off the refrigerant flow. According to the invention, the deactivation of the second heat exchanger is achieved by shutting off the air flow, i.e., by closing the radiator grille shutter. Particularly under low-load conditions, closing the radiator grille shutter can significantly reduce the vehicle's aerodynamic drag depending on the cooling demand and / or the vehicle speed above a certain limit, thus improving energy efficiency.

[0021] According to yet another aspect, in the second operating mode, condensate formed at the third heat exchanger is directed to the first heat exchanger to provide evaporative cooling. Such evaporative cooling may be employed upon detection of a high-load cooling condition and / or a high ambient temperature above a certain threshold.

[0022] The mentioned different trigger points and limits can be different and independent of each other, i.e. the limit temperatures for switching to the second operating mode, the limit for applying evaporative cooling, the limit for opening or closing the bypass or the limit for opening or closing the grille shutter.

[0023] The invention will now be explained in more detail using exemplary embodiments and with reference to the figures. Fig. 1 shows a schematic view of the vehicle air conditioning system adapted for a thermal management system according to an embodiment of the present disclosure, Fig. 2 - 3 show schematic views of circuits of a refrigerant circuit for a thermal management system according to an embodiment of the present disclosure, Fig. 4 - 5 show schematic views of a modified vehicle air conditioning system and a layout of a modified refrigerant circuit according to the Fig. 1 and Fig. 2 for a second embodiment, Fig. 6 shows a schematic view of a circuit of a coolant circuit for a thermal management system according to an embodiment of the present disclosure, and Fig. 7 shows a flowchart of a method for operating a thermal management system according to an embodiment of the present disclosure.

[0024] Relevant parts of the thermal management system 10 for a vehicle according to the present disclosure include a vehicle air conditioning system 20, a refrigerant circuit 30, a coolant circuit 40, a grille closure 50 and a control unit 60. While the vehicle air conditioning system 20 with respect to Fig. 1, the overall concept can best be explained with reference to the Fig. 2. The coolant circuit is then explained in more detail with reference to Fig. 6 explained.

[0025] As in Fig. As can be seen in Figure 2, the thermal management system 10 has a refrigerant circuit 30, comprising a compressor 31 and an expansion valve arrangement 32, a first heat exchanger designed as an internal gas cooler 33, which is connected in the high-pressure section downstream of the compressor 31 and upstream of the expansion valve arrangement 32. A low-pressure heat exchanger arrangement (consisting of a third heat exchanger as an evaporator 34 and a fourth heat exchanger as a chiller 35) is connected in the low-pressure section downstream of the expansion valve arrangement 32 and upstream of the compressor 31. A second heat exchanger designed as an external heat exchanger 36 is adapted to be operated in thermal exchange in the exhaust air stream 51 with the outside environment, and can be switched into the high-pressure section in a cooling mode and into the low-pressure section in a heating mode.

[0026] A radiator 43 is arranged in the exhaust air flow 51 of the vehicle downstream of the exterior heat exchanger 36. The radiator grille shutter 50 upstream of both the exterior heat exchanger 36 and the radiator 43 can be opened and closed. The radiator 43 and the chiller 35 are thermally coupled to the coolant circuit 40. As a consequence of the heat dissipation through the second air duct 25 in the vehicle air conditioning system 20 (see Fig. 1), the outdoor heat exchanger 36 can be operated with reduced heat output, so that the coolant-side (low-temperature) radiator 43 is even effectively operated downstream of the outdoor heat exchanger 36.

[0027] A control unit 60 is configured to control the operation of the thermal management system 10. As will be appreciated by those skilled in the art, it may be connected to sensors, actuators, pumps, and valves and may send and receive electrical signals to effect the operation of the system.

[0028] According to Fig. 1 illustrates a schematic view of a vehicle air conditioning system 20 for a thermal management system 10 according to an embodiment of the present disclosure. The vehicle air conditioning system 20 includes an air inlet 21 (which may have one or more openings, such as a fresh air opening and a recirculated air opening) and an array of air outlets 22 (which typically include multiple outlets for the face, foot area, and windshield) opening into a compartment to be air-conditioned, such as a passenger cabin 15. A first air duct 24 (indicated by an arrow) is designed to convey air from the air inlet 21 to the air outlets 22 by means of a fan 23 arranged proximate the air inlet 21.

[0029] As is known per se, various heat exchangers are housed in the first air duct 24 to condition the air for cooling, heating, and dehumidification. In the present embodiment, heating is provided by a condenser or internal gas cooler 33, which may be supplemented by a PTC element, while cooling is provided by an evaporator 34 upstream in the air duct 24. An air flap 27A, designed here as a sliding door, allows dehumidified, cold air that has passed through the evaporator 34 to be directed either through and / or past the internal gas cooler 33, enabling mixing downstream to achieve the air conditioning target for the passenger cabin 15.

[0030] Downstream of the inner gas cooler 33, the first air duct 24 comprises a closable and openable second air duct 25 (indicated by a small arrow), which branches off into an area below the vehicle body so that warm air which has passed through the inner gas cooler 33 can be separated by the air flap 27B from the normal air flow provided to the passenger cabin 15. As will be readily appreciated by those skilled in the art and with reference to the Fig. 2 and Fig. As explained in Figure 3, in cooling modes, the internal gas cooler does not need to be bypassed on the refrigerant side because heat is dissipated to the outside of the passenger compartment 15. As a consequence, the layout of the refrigerant circuit can be simplified.

[0031] In addition, an openable and closable bypass 26 (indicated by a small arrow) is formed around the evaporator 34 to supply air from the air inlet 21 to the internal gas cooler 33 without passing through the evaporator 34. In typical operating modes, the bypass 26 is closed by the air damper 27C to ensure that the air is properly dehumidified. As described in connection with Fig. 5, for some cooling operating modes with increased cooling power requirements, the air flap 27C can be opened to increase the heat dissipation inside the gas cooler 33, which can then be dissipated to the outside of the vehicle via the opened second air duct 25.

[0032] The internal gas cooler 33 can be positioned so that condensate formed at the evaporator 34 can be directed to the internal gas cooler 33 to provide evaporative cooling. Such conduction can be achieved by gravity and airflow. Alternatively or additionally, this can be supported by guide channels (not shown).

[0033] The Fig. 2 and Fig. 3 show schematic views of a refrigerant circuit 30 for a thermal management system 10 according to an embodiment of the present disclosure in two different operating modes. The circuit layout is substantially identical and shows deactivated branch lines in dashed lines. Fig. 3 only the relevant reference numerals are shown, the others are to those in Fig. 2 and have therefore been omitted. The thermal management system 10 is designed to be operated in a first operating mode, wherein the second air duct 25 ( Fig. 1) is closed, and to be operated in a second operating mode, wherein the second air duct 25 is opened to allow thermal energy to be removed from the vehicle air conditioning system, as described in connection with the flow diagram in the Fig. 7 is explained in more detail.

[0034] The refrigerant circuit 30 according to the present disclosure comprises a compressor 31 and a first expansion valve arrangement 32 consisting of a shut-off valve 32A and fully openable and closable expansion valves 32B, 32C. While the expansion valve 32B contributes to regulating the pressure drop upstream of the evaporator 34, the expansion valve 32C contributes to regulating the pressure drop upstream of the chiller 35. The evaporator 34 and chiller 35 form a parallel arrangement of low-pressure heat exchangers. In simpler configurations, the expansion valve arrangement 32 may also consist of only a single expansion valve (not shown). To ensure a defined refrigerant state downstream of the evaporator 34, the outlet of the evaporator 34 is connected to an accumulator 37 and is further guided through the low-pressure side of an internal heat exchanger 38 back to the suction side of the compressor 31.

[0035] The internal gas cooler 33 is integrated in the high-pressure section downstream of the compressor 31 and upstream of the expansion valve assembly 32. In cooling modes, the external heat exchanger 36 can be switched to the high-pressure section downstream of the internal gas cooler 33 and operates there. An expansion valve 32D can regulate a pressure level between the internal gas cooler 33 and the external heat exchanger 36.

[0036] In the second operating mode, the internal gas cooler 33 does not need to be deactivated on the refrigerant side, because it can be cooled down by condensate 28 from the evaporator 34. Excess thermal energy can be dissipated via the second air duct 25, as described with reference to Fig. 1. The shutoff valve 32A is closed. Consequently, refrigerant will flow from the compressor 31 through the internal gas cooler 33, the external heat exchanger 36, and the high-pressure side of the internal heat exchanger 38 to the expansion valve assembly 32, and further through the low-pressure side back to the compressor 31. In addition, the grille shutter 50 is open, allowing excess thermal energy to be dissipated via the external heat exchanger 36, the radiator 43, and the exhaust air stream 51.

[0037] In contrast to Fig. 2 is in Fig. 3, the radiator grille closure 50 is closed. Instead, the outdoor heat exchanger 36 is deactivated on the refrigerant side by closing the expansion valve 32D and opening the shut-off valve 32A.

[0038] According to a second embodiment of the present disclosure, as shown in the Fig. 4 and Fig. 5, the vehicle air conditioning system 20 from Fig. 1 and the refrigerant circuit 30 from the Fig. 2 and Fig. 3 has minor modifications. The difference is that instead of a direct arrangement of the gas cooler 33 in the first air duct 24, a water-cooled gas cooler 102 supplies the thermal energy to a heater core 103 via a secondary coolant circuit 101 and a pump 104. This heater core 103 is instead arranged in the first air duct 24.

[0039] The secondary coolant circuit can be connected to the coolant circuit 40 via appropriate pipes and valves (not shown).

[0040] Fig. 6 shows a schematic view of a coolant circuit 40 for a thermal management system 10 according to an embodiment of the present disclosure. The coolant circuit 40 has pumps 42A, 42B for circulating the coolant through various coolant branches 45A-45C, namely a first coolant branch 45A with the radiator 43, a second coolant branch 45B in thermal exchange with vehicle drive components 41A or a battery 41B, and a third coolant branch 45C in thermal exchange with the chiller 35. Depending on the purpose, these coolant branches 45A-45C can be combined or operated separately using switching or proportional valves 44A, 44B. As will be readily apparent to those skilled in the art, the coolant circuit can be simplified or include additional branches or bypasses that are in thermal contact with other components, heat exchangers, or electric heaters, as is known per se (not shown).

[0041] With reference to Fig. Figure 7 briefly explains an embodiment of a method for operating such a thermal management system 10. The flowchart of the operating sequence is limited to cooling operating modes (both the gas cooler 33 and the external heat exchanger 36 are operated on the high-pressure side of the refrigerant circuit 30). This can be understood as a subroutine of a broader operating concept with additional operating modes (such as one or more heating modes).

[0042] In step 100, the subroutine is started, e.g., by being called from a main routine. In step 110, a check is made to determine whether any cooling function is required, such as cooling the passenger compartment 15 or cooling the battery 41B. If so, the routine continues with step 120; otherwise, it stops with step 200.

[0043] In step 120, the ambient air temperature is compared with a temperature threshold to obtain an initial indication of a cooling requirement. The temperature threshold may be a fixed value or one modulated by other parameters (such as sunshine) and is typically in a range between 20° - 35°, e.g. 30°C. If the ambient temperature does not exceed the temperature threshold, the system proceeds to step 130 and is started in the first operating mode (normal cooling mode). Otherwise, the system proceeds to step 140 and is operated in the second operating mode (special cooling mode). In an alternative embodiment, the system is automatically started with the first operating mode, i.e., normal cooling mode, at step 130 if the need to switch to a cooling mode was detected at step 110.The temperature check at step 120 can be performed at regular intervals or based on a trigger that the ambient temperature increases (not shown).

[0044] At step 130, the second air duct 25 and the bypass 26 around the evaporator 34 are closed by the air dampers 27B and 27C. Condensate is drained from the evaporator 34 in the usual manner from the vehicle air conditioning system 20, typically being vented outside to the floor of the vehicle (action in the vehicle air conditioning system 20). The expansion valve 32D is open (with or without generating a pressure stage), the shut-off valve 32A is closed, and the expansion valves 32B, 32C are operated according to the control parameters to achieve the target temperatures at the evaporator 34 and the chiller 35 (actions in the refrigerant circuit 30). The grille shutter 50 is open to allow normal heat removal from the vehicle system via the exterior heat exchanger 36 and / or radiator 43.

[0045] In step 140, the second air duct 25 and the bypass 26 around the evaporator 34 are opened by the air dampers 27B and 27C to allow thermal energy to be removed from the vehicle air conditioning system 20. Optionally, condensate from the evaporator 34 is collected and directed to the surface of the internal gas cooler to enable evaporative cooling. The speed of the fan 23 can be increased to compensate for the pressure losses due to the open second air duct and the bypass 26 (measures in the vehicle air conditioning system 20). The position of the valves / expansion valves and the opening of the radiator grille are the same as in step 130.

[0046] In normal cooling mode, a periodic check is performed at step 150 to determine whether the cooling target has been reached. This can be accomplished by any suitable means, e.g., typically by comparing the temperature of the air exiting the evaporator 34 and / or the coolant temperature at the outlet of the chiller 35 with a target value. If this is the case, normal cooling mode continues according to step 130; otherwise, the system proceeds to step 160 and switches to a third operating mode (special reheat mode).

[0047] At step 160, the second air duct 25 and the bypass 26 around the evaporator 34 are opened by the air dampers 27B and 27C to allow thermal energy to be removed from the vehicle air conditioning system 20. Condensate is discharged from the evaporator 34 in the usual manner, typically to the outside of the vehicle's floor. The speed of the fan 23 may be increased if necessary to compensate for the pressure loss through the opened second air duct 25 and the bypass 26 (measures in the vehicle air conditioning system 20). The expansion valve 32D is closed to deactivate the outdoor heat exchanger 36. Furthermore, the shut-off valve 32A is opened and the expansion valves 32B, 32C are operated according to the control parameters so that the target temperatures at the evaporator 34 and chiller 35 are reached (measures in the refrigerant circuit 30).The grille shutter 50 can be closed, especially at higher vehicle speeds, to reduce the vehicle's aerodynamic drag and save energy. Because the exterior heat exchanger 36 has been deactivated on the refrigerant side, there is no risk of overheating if the exterior heat exchanger 36 is not cooled by the exhaust air flow 51. Instead of using the exterior heat exchanger 36, the heat is dissipated through the second air duct 25.

[0048] As will be readily apparent to a person skilled in the art, the second and third operating modes can be combined into a single "special" cooling mode with two variants. The common feature is the use of the second air duct 25 to dissipate thermal energy from the vehicle.

[0049] Similar to step 150, a regular check is performed in step 170 to determine whether the cooling air conditioning target has been reached. If so, the third cooling mode (or the special cooling mode, second variant) continues to operate according to step 160; otherwise, the system proceeds to step 140 and switches to the second operating mode (or the special cooling mode, first variant).

[0050] The system can receive triggers to stop cooling mode at any time. This can be triggered by a temperature signal, e.g., when the outside temperature has dropped, by turning off the vehicle, or by a manual user input (not shown). In such a case, the routine stops at step 200. REFERENCE SYMBOL 10 Thermal management system 15 Passenger cabin, compartment 20 Vehicle air conditioning 21 Air intake 22 air outlets 23 blowers 24 First air duct 25 Second air duct 26 Bypass around the evaporator 27A - 27C Air dampers 28 Condensation 30 Refrigerant circuit 31 Compressor 32 Expansion valve arrangement 32A shut-off valve 32B - 32D expansion valves 33 Internal gas cooler / First heat exchanger 34 Evaporator / Third heat exchanger 35 Chiller / Fourth heat exchanger 36 Outdoor heat exchanger / Second heat exchanger 37 Accumulator 38 Internal heat exchanger 40 Coolant circuit 41A Vehicle drive components 41B battery 42A, 42B pumps 43 Radiator / coolant radiator 44A - 44B Switching valves / Proportional valves 45A - 45C coolant branches 50 grille closure 51 Exhaust air flow (ambient air) 60 control unit 101 Secondary coolant circuit, coolant loop 102 Water-cooled gas cooler (first heat exchanger, indirect heater) 103 Heater core (coolant-air heat exchanger) 104 Pump

Claims

[1] Thermal management system (10) for a vehicle, comprising: - a vehicle air conditioning system (20) with: - an air inlet (21), - an arrangement of air outlets (22) communicating with a compartment (15) to be air-conditioned, and - a first air duct (24) which conveys air from the air inlet (21) to the arrangement of air outlets (22) by means of a fan (23), - a refrigerant circuit (30) with: - a compressor (31), - a first expansion valve arrangement (32), - a first heat exchanger (33; 102) which is connected in the high-pressure section downstream of the compressor (31) and upstream of the first expansion valve arrangement (32), - a low-pressure heat exchanger arrangement (34; 35) which is connected in the low-pressure section downstream of the first expansion valve arrangement (32) and upstream of the compressor (31), and - a second heat exchanger (36) which is adapted to be operated in thermal exchange in an exhaust air flow (51) with the outside environment and to be switchable into the high-pressure section in cooling mode and into the low-pressure section in heating mode, and - a control unit (60) for controlling the operation of the thermal management system (10), wherein - the first heat exchanger (33; 102) connected in the high-pressure section is used to heat the air conveyed into the compartment (15) to be air-conditioned and is arranged either in the first air duct (24) or as an indirect heater (102) which transfers the heat via a coolant loop (101) to a coolant-air heat exchanger (103) arranged in the first air duct (24), and - downstream of the first heat exchanger (33) or the coolant-air heat exchanger (103), the first air duct (24) has an openable and closable second air duct (25) which branches off into an area outside the compartment (15) to be air-conditioned, characterized by , that - an openable and closable radiator grille closure (50) is arranged upstream of the second heat exchanger (36) and upstream of an optional coolant radiator (43) in the air flow direction of the exhaust air flow (51), which is coupled to the second air duct (25) in such a way that at least one of the radiator grille closure (50) and / or the second air duct (25) is open. [2] Thermal management system (10) according to claim 1, characterized bya coolant circuit (40) in thermal exchange with the low-pressure heat exchanger arrangement (34; 35) with at least one pump (42A, 42B) and the coolant radiator (43), which is adapted to be operated in the exhaust air flow (51) in thermal exchange with the outside environment. [3] Thermal management system (10) according to claim 2, characterized by , that - the low-pressure heat exchanger arrangement (34; 35) comprises a third heat exchanger (34) and a fourth heat exchanger (35), - the first heat exchanger (33) is arranged downstream of the third heat exchanger (34) in the first air duct (24), and - the fourth heat exchanger (35) is in thermal contact with the coolant circuit (40). [4] Thermal management system (10) according to claim 3, characterized bythat an openable and closable bypass (26) is formed around the third heat exchanger (34) in order to supply air from the air inlet (21) to the first heat exchanger (33) without passing through the third heat exchanger (34). [5] Thermal management system (10) according to one of claims 3 or 4, characterized by that the first heat exchanger (33) is arranged downstream of the third heat exchanger (34) in the first air duct (24) such that condensate (28) formed at the third heat exchanger (34) is conducted to the first heat exchanger (33) to provide evaporative cooling. [6] Thermal management system (10) according to one of claims 2 to 5, characterized by that the coolant radiator (43) is arranged downstream of the second heat exchanger (36) in the exhaust air flow (51). [7] Method for operating a thermal management system (10) according to one of the preceding claims, characterized by , that - the thermal management system (10) is operated in a first operating mode, wherein the second air duct (25) is closed, and - the thermal management system (10) is operated in a second operating mode, which is a cooling mode, wherein the second air duct (25) is opened to allow the dissipation of thermal energy from the vehicle air conditioning system (20), and optionally the speed of the fan (23) is adjusted, wherein the second heat exchanger (36) is deactivated by closing the radiator grille closure (50). [8] Method for operating a thermal management system (10) according to claim 7, characterized by that both the first operating mode and the second operating mode are cooling modes in which the first heat exchanger (33) and the second heat exchanger (36) are operated in the high-pressure section of the refrigerant circuit (30). [9] Method for operating a thermal management system (10) according to one of claims 7 or 8, characterized by that in the second operating mode - the bypass (26) around the third heat exchanger (34) is open, and - the speed of the fan (23) is increased. [10] Method for operating a thermal management system (10) according to one of claims 7 to 9, characterized by that in the second operating mode, condensate water (28) formed at the third heat exchanger (34) is passed to the first heat exchanger (33) to provide evaporative cooling.

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