Air-Conditioning System for an Electrically Driveable Motor Vehicle, Motor Vehicle and Method for Operating an Air-Conditioning System

Abstract

Please substitute the new Abstract submitted herewith for the original Abstract: An air-conditioning system for an electrically driveable motor vehicle includes a coolant-conducting HVA circuit to which a traction battery and an evaporator for cooling the traction battery are connected, a coolant-conducting heating circuit for controlling the temperature of an interior compartment of the motor vehicle, to which heating circuit a condenser for releasing thermal power is connected, a coolant-conducting refrigeration circuit, to which the evaporator, the condenser and a compressor are connected, a heat exchanger, which is connected to the HVA circuit and which is controllably connectable to the heating circuit and which is configured for coolant-based transfer of thermal power from the heating circuit into the HVA circuit, and a control device.

Claims

1-12. (canceled)

13. An air-conditioning system for an electrically driveable motor vehicle, the air-conditioning system comprising: a coolant-conducting HVA circuit, to which a traction battery for providing a supply to an electric drive unit of the motor vehicle, and an evaporator for cooling the traction battery, are connected; a coolant-conducting heating circuit for controlling a temperature of an interior compartment of the motor vehicle, to which heating circuit a condenser for releasing thermal power is connected; a refrigerant-conducting refrigeration circuit, to which the evaporator, the condenser and a compressor are connected; a heat exchanger, which is connected to the HVA circuit and is connectable in a controllable manner to the heating circuit, and which is configured for coolant-based transmission of thermal power from the heating circuit into the HVA circuit; and a control device, which, for heating of the traction battery and/or the interior compartment by way of the thermal power of the condenser, is configured to connect the heat exchanger to the heating circuit such that a thermal short-circuit is formed between the condenser and the evaporator, in order for at least a portion of the thermal power of the condenser to be transmitted into the HVA circuit, and to operate the compressor in order for at least a portion of the thermal power of the condenser that is transmitted into the HVA circuit to the evaporator to be fed back into the heating circuit, wherein the thermal power arising at the condenser and fed back into the heating circuit is increased by a thermal power resulting from operation of the compressor.

14. The air-conditioning system according to claim 13, wherein: the heat exchanger is arranged in the HVA circuit directly upstream of the evaporator.

15. The air-conditioning system according to claim 13, wherein: the heating circuit has a heating device for providing thermal power, and the control device, for heating of the traction battery, is configured such that, for transmission of at least a portion of the thermal power of the heating device into the HVA circuit, the control device connects the heat exchanger to the heating circuit, so that the heating device is connected to the HVA circuit.

16. The air-conditioning system according to claim 13, wherein: the air-conditioning system has a coolant-conducting cooling circuit, to which the electric drive unit of the motor vehicle is connected and which is coupled fluidically to the HVA circuit, the control device, for heating of the traction battery, is configured such that, for transmission of at least a portion of a thermal power of the electric drive unit to the HVA circuit, the control device additionally connects the cooling circuit to the HVA circuit, and the thermal power of the electric drive unit is constituted by heat losses of the electric drive unit.

17. The air-conditioning system according to claim 16, wherein: the control device is configured to operate the electric drive unit in an inefficient operation mode for a purpose of increasing released heat losses.

18. The air-conditioning system according to claim 13, wherein: the control device is configured to divide the thermal power of the condenser among the traction battery and the interior compartment.

19. The air-conditioning system according to claim 13, wherein: the heat exchanger is connected to the heating circuit via a valve device, and the control device is configured to control, by way of the valve device, a proportion of the thermal power of the condenser that is transmitted from the heating circuit to the HVA circuit.

20. The air-conditioning system according to claim 13, wherein: the control device is configured to thermally short-circuit the condenser and the evaporator, and to operate the compressor, if a temperature of coolant in the HVA circuit is lower than a predetermined threshold value, so that the thermal power of the condenser that is transmitted into the HVA circuit is additionally configured for heating the evaporator.

21. The air-conditioning system according to claim 13, wherein: the control device is configured to make the traction battery available during a charging operation of the traction battery.

22. The air-conditioning system according to claim 13, wherein: the control device, for cooling of the traction battery, is configured such that, for a purpose of pre-cooling of coolant for the evaporator through transmission of thermal power from the HVA circuit into the heating circuit, the control device connects the heat exchanger to the HVA circuit and to the heating circuit.

23. An electrically driveable motor vehicle comprising the air-conditioning system according to claim 13.

24. A method for operating the air-conditioning system according to claim 13, wherein, for heating of the traction battery, and/or the interior compartment, by way of the thermal power of the condenser, the method comprises: connecting the heat exchanger to the heating circuit such that the thermal short-circuit is formed between the condenser and the evaporator, in order for at least a portion of the thermal power of the condenser to be transmitted into the HVA circuit, and operating the compressor in order for at least the portion of the thermal power of the condenser that is transmitted into the HVA circuit to the evaporator to be fed back into the heating circuit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG. 1 shows a schematic illustration of an embodiment of an air-conditioning system according to the invention.

[0028] FIG. 2 shows the air-conditioning system as per FIG. 1 in a heating mode of the traction battery.

[0029] FIG. 3 shows the air-conditioning system as per FIG. 1 in a cooling mode of the traction battery.

DETAILED DESCRIPTION OF THE DRAWINGS

[0030] In the figures, identical and functionally identical elements are denoted by the same reference signs.

[0031] FIG. 1 shows an embodiment of an air-conditioning system 1 for an electrically driveable motor vehicle (not shown here). The air-conditioning system 1 has a coolant-conducting overall cooling circuit 2 and a refrigerant-conducting refrigeration circuit 3. The air-conditioning system 1 can be operated in different operation modes, exemplary embodiments of which are shown in FIG. 2 and FIG. 3.

[0032] The overall cooling circuit 2 has here a cooling circuit 4, an HVA circuit 5 and a heating circuit 6. The HVA circuit 5 has a traction battery 7 of the motor vehicle and has an evaporator 8 for cooling the traction battery 7. The evaporator 8 is moreover connected to the refrigeration circuit 3 of the air-conditioning system 1. The HVA circuit 5 moreover has here an HVA pump 9, an HVA shut-off valve 10 upstream of the traction battery 7 and an HVA check valve 11 downstream of the traction battery 7. The HVA shut-off valve 10 and the HVA check valve 11 fluidically encapsulate the traction battery 7. The HVA circuit 5 has in particular no separate heater for heating the traction battery 7. The HVA circuit is therefore designed to be without heating.

[0033] The heating circuit 6, which is configured for air-conditioning an interior compartment of the motor vehicle, has here a heating device 12 which is configured for heating interior compartment air of the interior compartment. The heating device 12 has here a heating heat exchanger 13 and an auxiliary heater 14. The heating heat exchanger 13 can moreover transport heat out of the interior compartment for the purpose of cooling the interior compartment. The auxiliary heater 14 may for example be in the form of an electric flow heater (EFH). The heating circuit 6 furthermore has a heating-circuit pump 15 and a condenser 16. The condenser 16 is moreover connected to the refrigeration circuit 3. The refrigeration circuit 3 moreover has a compressor 17 and an expansion valve 18. The refrigeration circuit 3 can be operated in a heat-pump operation mode, in which thermal power can be transported, through operation of the evaporator 8, the compressor 17 and the condenser 16, from the HVA circuit 5 into the heating circuit 6.

[0034] The HVA circuit 5 and the heating circuit 6 can moreover be coupled via a heat exchanger 19. For this purpose, there is arranged in the heating circuit 6 a valve device 20, in the form of a three-way valve, via which the heat exchanger 19, which is connected to the HVA circuit 5, can also be connected to the heating circuit 6. Here, the heat exchanger is arranged upstream of the evaporator 8, in particular directly before the evaporator 8.

[0035] The cooling circuit 4 has an electric drive unit 21 of the motor vehicle. The electric drive unit 21 has for example at least one electric drive machine and power electronics. The cooling circuit 4 moreover has a surroundings cooler device 22 for exchange of heat with surroundings of the motor vehicle. By way of the surroundings cooler device 22, the electric drive unit 21 can be cooled during operation. The surroundings cooler device 22 has here a first surroundings cooler 23, a second surroundings cooler 24, a fan 25 and an expansion tank 26. The two surroundings coolers 23, 24 are arranged one behind the other in an ambient-air path 27, wherein the second surroundings cooler 24 is arranged downstream of the first surroundings cooler 23 with respect to the coolant but upstream of the first surroundings cooler 23 in the ambient-air path 27. The first surroundings cooler 23 may for example be an HT cooler or high-temperature cooler. The second surroundings cooler 24 may for example be an LT cooler or low-temperature cooler. In this case, colder coolant flows through the second surroundings cooler 24 than through the first surroundings cooler 23. The fan 25, for intake of ambient air, is arranged downstream of the two surroundings coolers 23, 24 in the ambient-air path 27. The cooling circuit 4 moreover has a cooling-circuit pump 28 for conveying the coolant in the cooling circuit 4.

[0036] The cooling circuit 4 and the heating circuit 6 can be coupled fluidically via a shut-off valve 29. It is thus possible for the heating circuit 6 to be connected to the surroundings cooler device 22 of the cooling circuit 4 for the purpose of cooling the interior compartment. For this purpose, heat is transported from the interior compartment into the heating circuit 6 via the heating heat exchanger 13 and is discharged to the surroundings cooler device 22. Moreover, the cooling circuit 4 and the HVA circuit 5 can be coupled fluidically via a three-way valve 30 upstream of the drive unit 21 and via a three-way valve 31 downstream of the drive unit 21. The electric drive unit 21 can be connected to the HVA circuit 5 via the three-way valves 30, 31. A control device 32 of the air-conditioning system 1 is configured for controlling components of the air-conditioning system 1.

[0037] FIG. 2 and FIG. 3 show different operation modes of the air-conditioning system 1. Here, paths active in the respective operation mode are shown in bold. FIG. 2 shows an operation mode in the form of a heating mode for the traction battery 7. In the heating mode, at least portions of the thermal powers of the condenser 16, the heating device 12 and the electric drive unit 21 are fed here to the traction battery 7. In order for the thermal power of the electric drive unit 21 to be fed into the HVA circuit 5, the control device 32 transfers the three-way valves 30, 31 into a switching state in which at least a portion of the coolant circulating in the coolant circuit 4 flows into the HVA circuit 5. This coolant transports thermal power in the form of heat losses of the electric drive unit 21. Here, the coolant flows from the drive unit 21 and, via the three-way valve 31, into the HVA circuit 5. There, said coolant flows via the heat exchanger 19, the evaporator 8 and the traction battery 7 to the three-way valve 30 and, from there, back into the cooling circuit 4 and to the drive unit 21. In order for the heat losses of the electric drive unit 21 and thus the thermal power for the traction battery 7 to be increased, the control device 32 can operate the drive unit 21 for example in an inefficient, power-loss-increasing operation mode.

[0038] The thermal powers of the heating device 12 and the condenser 16 are transported from the heating circuit 6 into the HVA circuit 5 via the heat exchanger 19. For this purpose, the control device 32 connects the heat exchanger 19 to the heating circuit 6 by way of the three-way valve 20. Here, the three-way valve 20 is transferred into a switching state in which at least a portion of the coolant flows via the heat exchanger 19. Moreover, the control device 32 controls the heating device 12, in particular the auxiliary heater 14, to generate heating power. Said heating power is at least partially transported as thermal power into the HVA circuit 5 via the heat exchanger 19. A remaining portion of the heating power of the heating device 12 can be used for heating the interior compartment.

[0039] Through the connection of the heat exchanger 19 to the heating circuit 6 and to the HVA circuit 5, it is moreover the case that the evaporator 8 and the condenser 16 are thermally short-circuited. The refrigeration circuit 3 is thus operated in a short-circuit operation. In said short-circuit operation, the control device 32 operates the compressor 17. For this purpose, an in particular increased drive power is fed to the compressor 17. Said increased drive power of the compressor 17 is converted into thermal power, which arises at the condenser 16. This thermal power arising at the condenser 16 that is generated with the aid of the compressor 17 is likewise fed at least partially into the HVA circuit 5 via the heat exchanger 19, in order, for example, for the traction battery to be heated, on the one hand, and for a portion of the thermal power to be transferred into the heating circuit 6 via the refrigeration circuit 3 again, on the other hand. During the transfer of the thermal power into the heating circuit via the refrigeration circuit 3, the thermal power of the compressor 17 is added to this power, so that an increased thermal power arises at the condenser 16. The feeding of thermal power from the heating circuit 6 back into the HVA circuit 5 and the transporting of at least a portion of the fed-back heat back into the heating circuit 6 via the refrigeration circuit 3 thus allows the thermal power arising at the condenser 16 to be increased. This increased thermal power can in turn be at least partially fed back into the HVA circuit 5 via the heat exchanger 19. It is also possible for a portion of the thermal power arising at the condenser 16 to remain in the heating circuit 6 and be used there for heating the interior compartment.

[0040] This short-circuit operation is particularly advantageous in particular in the case of low outside temperatures at which the heat-pump operation cannot be provided, or cannot be provided efficiently, owing to a lack of operational readiness of the evaporator 8. Such a lack of operational readiness of the evaporator 8 can result for example from the evaporator 8 icing up. Thus, in short-circuit operation, the drive power of the compressor 17 can be used as thermal power for heating the traction battery 7. The traction battery 7 can thus be heated in the heating mode by three heating sources, specifically the drive unit 21, the heating device 12 and the condenser 16 or the compressor 17. Through the interconnection of said heating sources with the traction battery 7 in the air-conditioning system 1, it is moreover possible for unnecessary heating of other components of the air-conditioning system 1 to be prevented.

[0041] FIG. 3 shows an operation mode in the form of a cooling mode for the traction battery 7. In the cooling mode, the traction battery 7 is cooled via the evaporator 8 in that coolant circulates in the HVA circuit 5 and waste heat of the traction battery 7 is transported to the evaporator 8. Moreover, the heat exchanger 19 is connected to the HVA circuit 5 and to the heating circuit 6 by the control device 32. Via said heat exchanger 19, transporting of thermal power from the HVA circuit 5 into the heating circuit 6, and consequently pre-cooling of the coolant for the evaporator 8, are possible. The thermal power transported into the heating circuit 6 can be discharged for example via the surroundings cooler device 22. For this purpose, the heating circuit 6 is coupled fluidically to the cooling circuit 4 via the shut-off valve 29.