Heat pump system

Abstract

The invention relates to a heat pump system (1) for a motor vehicle. The heat pump system (1) comprises a refrigerant circuit (2) which contains a first sub-circuit (9a) with a low-pressure accumulator (10) and a second sub-circuit (9b). According to the invention, the refrigerant circuit (2) comprises a valve device (17), wherein the first sub-circuit (9a) and the second sub-circuit (9b) are fluidically connected to each other only by means of this valve device (17).

Description

Technical Field

[0001] This invention relates to a heat pump system for motor vehicles. Background Technology

[0002] Heat pump systems are particularly suitable for energy-efficient heating of electrified motor vehicles. Here, the heat pump system uses waste heat from the vehicle and / or ambient heat as a heat source and a refrigerant as a heat transfer medium. Disadvantageously, such heat pump systems have several components associated with high costs. These costs are also particularly incurred by the valves and piping used in the heat pump system. Furthermore, such heat pump systems require significant installation space. Summary of the Invention

[0003] Therefore, the object of the present invention is to provide an improved or at least alternative embodiment for general-type heat pump systems, wherein the described disadvantages are overcome.

[0004] This invention is based on the following general concept: a heat pump system optimized in terms of installation space and cost is manufactured by intelligent interconnection of heat exchangers on the basis of a low-pressure accumulator. The heat pump system according to the invention is configured for use in motor vehicles. The heat pump system here has a refrigerant circuit through which refrigerant can flow, the refrigerant circuit having a first sub-circuit and a second sub-circuit. The first sub-circuit includes a low-pressure accumulator, a compressor, a heat pump heater, and an external heat exchanger. The second sub-circuit includes an evaporator and a cooler. According to the invention, the refrigerant circuit has a valve device, wherein the first sub-circuit and the second sub-circuit are fluidly connected to each other only through the valve device.

[0005] In the heat pump system according to the invention, two sub-loops are connected in a fluid-guided manner via valve devices. The first and second sub-loops can be circulated by refrigerant and can be interconnected with each other in different ways via the valve devices. Therefore, the heat pump system can operate in a cooling mode, a first heating mode, and a second heating mode, as will be explained in more detail below. Advantageously, the valve devices can have at least one sensor for detecting the pressure and / or temperature of the refrigerant. Based on this, the heat pump system can then be connected.

[0006] A heat pump heater can be a refrigerant-air heat exchanger. Specifically, a heat pump heater can be integrated into the air conditioning system of a motor vehicle. Here, the heat pump heater is used for heat exchange between the refrigerant and the interior air, which flows into the interior space of the motor vehicle within the air conditioning system. Therefore, in this case, the heat pump heater is configured to be traversed by both the refrigerant and the interior air.

[0007] The external heat exchanger can be a refrigerant-air heat exchanger, and can be used for heat exchange between the refrigerant and the ambient air flowing outside the motor vehicle. Therefore, in this case, the external heat exchanger is configured to be able to be traversed by both refrigerant and ambient air.

[0008] An evaporator can be a refrigerant-air heat exchanger. Specifically, an evaporator can be part of a vehicle's air conditioning system. Here, the evaporator is used for heat exchange between the refrigerant and interior air, which flows into the vehicle's interior space within the air conditioning system. Therefore, in this case, the evaporator is configured to be traversed by both refrigerant and interior air.

[0009] Advantageously, the valve assembly can be securely connected to the low-pressure accumulator, forming a separate structural unit that is structurally integrated, particularly capable of being prefabricated or prefabricated separately. In the valve assembly, at least one valve and multiple pipelines of the heat pump system can be interconnected. The valve assembly and the corresponding at least one valve are securely connected to the low-pressure accumulator, wherein the at least one valve is preferably flanged to the low-pressure accumulator. Because at least one valve and pipeline with the low-pressure accumulator are combined into a separate, structurally integrated structural unit, the number of components in the heat pump system can be reduced, thereby lowering the cost of the heat pump system. Furthermore, through the separate, structurally integrated structural unit, the heat pump system is constructed in a particularly space-saving and compact manner. This structural unit can also be prefabricated, allowing the installation and manufacturing processes to be separated.

[0010] Advantageously, the heat pump system can have at least one coolant circuit, wherein the at least one coolant circuit can be connected to the coolant circuit in a heat transfer manner via a refrigerator of a second sub-circuit. Therefore, the refrigerator can be a refrigerant-coolant heat exchanger and can be used for heat exchange between refrigerant and coolant flowing in at least one coolant circuit of the heat pump system. Thus, in this case, the refrigerator is configured to be traversed by both refrigerant and coolant. At least one coolant circuit can be used, for example, to cool other components of the motor vehicle (e.g., the battery).

[0011] Advantageously, it can be specified that the low-pressure accumulator, compressor, heat pump heater, and external heat exchanger in the first sub-loop are connected to each other in a fluid-guided and series manner via the first sub-loop pipeline. The first sub-loop pipeline is fluid-guided to a valve device at its inlet upstream of the low-pressure accumulator and at its outlet downstream of the external heat exchanger. In the first sub-loop, the external heat exchanger can be bypassed via a bypass pipeline. This bypass pipeline is fluid-guided to the first sub-loop pipeline at its bypass inlet upstream of the external heat exchanger and to the valve device at its bypass outlet. Therefore, in the first sub-loop, the first sub-loop inlet, low-pressure accumulator, compressor, heat pump heater, external heat exchanger, and first sub-loop outlet can be sequentially passed through. Furthermore, the external heat exchanger can be bypassed via the bypass pipeline. The first sub-loop inlet, first sub-loop outlet, and bypass outlet are fluidly connected to the valve device, allowing the valve device to regulate the flow of refrigerant through the bypass pipeline and the first sub-loop pipeline.

[0012] Advantageously, in the second sub-loop, the evaporator and the refrigerant can be connected to each other in a fluid-guided and parallel manner via a second sub-loop line. The second sub-loop line is then fluid-guidedly connected to a valve device at a second sub-loop inlet located upstream of the evaporator and the refrigerant and at a second sub-loop outlet located downstream of the evaporator and the refrigerant. Thus, in the second sub-loop, the refrigerant and the evaporator can flow parallel to each other. The second sub-loop inlet and outlet are fluidly connected to the valve device, allowing the valve device to regulate the flow of refrigerant through the second sub-loop line.

[0013] Furthermore, the heat pump system can have an adjustable expansion valve located directly upstream of the external heat exchanger. Additionally, the heat pump system can be specified to have adjustable expansion valves located directly upstream of the refrigerant and directly upstream of the evaporator. The term "direct" means that there is no other functional component connection between the corresponding expansion valve and the external heat exchanger, evaporator, or refrigerant. The flow of refrigerant can be affected by the corresponding expansion valve. Therefore, the corresponding expansion valve can open or close, or can act as a throttling valve. The corresponding expansion valve can be, for example, an electrically operated expansion valve.

[0014] The heat pump system can advantageously operate in cooling mode. In cooling mode, the expansion valve at the external heat exchanger opens without throttling. In contrast, the expansion valves at the cooler and evaporator each act as throttling valves. Furthermore, the bypass line in the first sub-loop is closed via a valve assembly; the fluid outlet of the first sub-loop is connected to the inlet of the second sub-loop; and the fluid outlet of the second sub-loop is connected to the inlet of the first sub-loop.

[0015] The flow path of the heat pump system in cooling mode will now be explained in more detail. In the first sub-loop, the refrigerant flows through the low-pressure accumulator and then through the compressor, where it is compressed. Afterward, the refrigerant flows to the heat pump heater. The heat pump heater can be part of the vehicle's air conditioning system, where no heat discharge occurs in the heat pump heater in cooling mode. Therefore, the heat pump heater is not traversed by air and is passive in terms of heat transfer. Thus, no heat exchange occurs between the refrigerant and the interior air in the heat pump heater. In cooling mode, the bypass line is closed, and the expansion valve at the external heat exchanger is open. Therefore, all the refrigerant flows through the heat pump heater and then through the external heat exchanger, where it discharges heat to the ambient air. Thus, the external heat exchanger operates as a condenser, and the refrigerant is liquefied in the external heat exchanger. The liquefied refrigerant then flows out of the first sub-loop at the first sub-loop outlet and is guided to the second sub-loop inlet via a valve device. Through the second sub-loop inlet, the refrigerant flows to the refrigerator and evaporator. Here, the refrigerant is throttled by expansion valves at the refrigerator and evaporator, causing a transition to lower pressure and lower temperature within the refrigerant. Consequently, the refrigerant can evaporate in the refrigerator and evaporator, accompanied by corresponding heat absorption. The refrigerator can be connected to the coolant circuit via heat transfer, and the heat absorption can cool the coolant flowing in the coolant circuit. For example, the coolant circuit can be used to cool other components of the vehicle (e.g., the battery). The evaporator can be part of the vehicle's air conditioning system, and the heat absorption can cool the interior air flowing within the air conditioning system. Subsequently, the refrigerant flows from the refrigerator and evaporator to the outlet of the second sub-circuit, and from there flows into the valve assembly. Through the valve assembly, the refrigerant is now guided back into the first sub-circuit, reaching the low-pressure accumulator.

[0016] Alternatively, the heat pump system can operate in a first heating mode. In the first heating mode, the expansion valves at the external heat exchanger and the refrigerator respectively act as throttling valves. On the other hand, the expansion valve at the evaporator is closed, thereby preventing refrigerant from flowing through the evaporator. Furthermore, a bypass outlet is fluidly connected to the inlet of the second sub-loop via a valve assembly; and the outlets of the first and second sub-loops are fluidly connected to the inlet of the first sub-loop.

[0017] The flow path of the heat pump system in the first heating mode will now be explained in more detail. In the first sub-loop, the refrigerant flows through the low-pressure accumulator and is compressed by the compressor. Thereafter, the refrigerant flows into the heat pump heater under high pressure and temperature. In the first heating mode, the heat pump heater acts as a condenser. In the heat pump heater, heat is extracted from the refrigerant, and the refrigerant is condensed. The heat pump heater can be part of the air conditioning system of a motor vehicle, and the heat discharge can heat the interior air flowing in the air conditioning system of the motor vehicle's interior space. The refrigerant condensed and liquefied in the heat pump heater now flows further to the bypass inlet. In the first heating mode, the expansion valve at the external heat exchanger acts as a throttle valve, and the bypass line is open. Therefore, a first portion of the refrigerant flows through the bypass line to the bypass outlet and is guided to the second sub-loop inlet by a valve device. In the second sub-loop, the expansion valve located upstream of the evaporator is closed, and the evaporator is not flowed through. The first portion of the refrigerant now flows only through the refrigerator and is throttled by an expansion valve located upstream of the refrigerator, causing a transition to low pressure and low temperature within the refrigerant. Subsequently, the first portion of the refrigerant evaporates in the refrigerator, accompanied by corresponding heat absorption. This heat absorption at the cooler can be used here in a cooling mode similar to that used for cooling coolant. The refrigerant then flows to the outlet of the second sub-loop and is guided to the inlet of the first sub-loop via a valve device. From there, the refrigerant flows to the low-pressure accumulator in the first sub-loop. The second portion of the coolant is throttled by an expansion valve at the external heat exchanger and subsequently evaporates in the external heat exchanger. After flowing through the external heat exchanger, the refrigerant flows to the outlet of the first sub-loop and is guided to the inlet of the first loop via a valve device. From there, the refrigerant flows to the low-pressure accumulator in the first sub-loop.

[0018] Alternatively, the heat pump system can operate in a second heating mode. In the second heating mode, the expansion valve at the external heat exchanger is closed, thereby closing the outlet of the first sub-loop. The expansion valve at the refrigerator acts as a throttling valve, and the expansion valve at the evaporator is closed. Furthermore, a bypass outlet is fluidly connected to the inlet of the second sub-loop via a valve assembly; and the outlet of the second sub-loop is fluidly connected to the inlet of the first sub-loop.

[0019] The flow path of the heat pump system in the second heating mode will now be explained in more detail. In the second heating mode, the expansion valve at the external heat exchanger and the outlet of the first sub-loop are closed. Therefore, compared to the first heating mode, all the refrigerant flows to the bypass outlet via the bypass line. Furthermore, the second heating mode corresponds to the first heating mode. The second heating mode is particularly advantageous when the temperature of the refrigerant at the cooler is higher than the temperature of the ambient air at the external heat exchanger. Otherwise, in the first heating mode, the temperature difference between the air and the refrigerant would cause undesirable refrigerant transfer to the external heat exchanger. In the second heating mode, the external heat exchanger can be shut off, thereby eliminating undesirable refrigerant transfer. Therefore, in the second heating mode, the cooler is used as the sole heat source.

[0020] In an advantageous embodiment, the valve device can have a first 2 / 1-way valve, a second 2 / 1-way valve, and a check valve. The first 2 / 1-way valve interconnects a first sub-circuit outlet and a first sub-circuit inlet. Here, the second 2 / 1-way valve interconnects a bypass outlet and a second sub-circuit inlet. Furthermore, the check valve fluidly connects a connection point upstream of the first 2 / 1-way valve to a connection point downstream of the second 2 / 1-way valve. Additionally, the second sub-circuit outlet is fluidly connected to the first sub-circuit inlet at a connection point downstream of the first 2 / 1-way valve.

[0021] In an alternative embodiment, the valve assembly can have a 2 / 1-way valve and a 3 / 2-way valve. The 2 / 1-way valve can then interconnect a bypass outlet and a second sub-loop inlet with each other. The 3 / 2-way valve can interconnect a first sub-loop outlet, a first sub-loop inlet, and a connection point located downstream of the 2 / 1-way valve with each other. Furthermore, the second sub-loop outlet can be fluidly connected to the first sub-loop inlet at a connection point located downstream of the 3 / 2-way valve.

[0022] In another alternative embodiment, the valve device can have a 4-way valve. Here, the 4-way valve can interconnect the first sub-loop outlet, the first sub-loop inlet, the bypass outlet, and the second sub-loop inlet with each other. Furthermore, the second sub-loop outlet can be fluidly connected to the first sub-loop inlet at a connection point located downstream of the 4-way valve.

[0023] Independent of the embodiments described herein, the valve device can be connected to the refrigerant circuit of the heat pump system, enabling the heat pump system to operate in the aforementioned mode. However, it should be understood that the embodiments of the valve device described herein are not definitive.

[0024] Other important features and advantages of the invention will become apparent from the accompanying drawings and the description thereof.

[0025] It should be understood that, without departing from the scope of the invention, the features mentioned above and further explained below can be used not only in the combinations presented separately, but also in other combinations or individually. Attached Figure Description

[0026] Preferred exemplary embodiments of the present invention are shown in the accompanying drawings and explained in more detail in the following description, wherein the same reference numerals denote the same or similar or functionally identical parts.

[0027] The following are schematically illustrated:

[0028] Figure 1 This is a circuit diagram of a heat pump system according to the present invention;

[0029] Figure 2 This is a circuit diagram of a heat pump system in cooling mode according to the present invention;

[0030] Figure 3 This is a circuit diagram of a heat pump system according to the present invention in the first heating mode;

[0031] Figure 4 This is a circuit diagram of a heat pump system according to the present invention in the second heating mode;

[0032] Figures 5 to 7 This is a view of valve devices with different configurations in a heat pump system according to the present invention. Detailed Implementation

[0033] Figure 1 A circuit diagram of a heat pump system 1 for a motor vehicle according to the present invention is shown. The heat pump system 1 here has a refrigerant circuit 2 through which refrigerant can flow and two coolant circuits 3a and 3b through which coolant can flow. Coolant circuits 3a and 3b are configured to cool components 4 of the motor vehicle. Coolant circuits 3a and 3b here include several valves 5, several pumps 6, a coolant cooler 7, and a heater 8. The two coolant circuits 3a and 3b are fluidly connected to each other via valves 5, so that the coolant can be cooled in a shared coolant cooler 7. However, the two coolant circuits 3a and 3b are also fluidly separated from each other via valves 5. The two coolant circuits 3a and 3b are connected to the refrigerant circuit 2 by heat transfer, which will be explained in more detail below.

[0034] The refrigerant circuit 2 has a first sub-circuit 9a and a second sub-circuit 9b.

[0035] The first sub-circuit 9a includes a low-pressure accumulator 10, a compressor 11, a heat pump heater 12, and an external heat exchanger 13. The heat pump heater 12 is a refrigerant-air heat exchanger and forms part of the vehicle's air conditioning system 14. Therefore, the heat pump heater 12 is configured to exchange heat between the refrigerant and the interior air IL flowing into the interior space in the air conditioning system 14. The external heat exchanger 13 is a refrigerant-air heat exchanger and is configured to exchange heat between the refrigerant and ambient air UL. In the first sub-circuit 9a, an adjustable expansion valve 13a is directly upstream of the external heat exchanger 13.

[0036] The second sub-circuit 9b includes an evaporator 15 and a refrigerant 16. An adjustable expansion valve 15a is located upstream of the evaporator 15, and an adjustable expansion valve 16a is located upstream of the refrigerant 16. Furthermore, a check valve 15b is located directly downstream of the evaporator 15. The evaporator 15 is a refrigerant-air heat exchanger and forms part of the air conditioning system 14 of the motor vehicle. The evaporator 15 is configured to exchange heat between the refrigerant and the interior air IL in the air conditioning system 14. The refrigerant 16 is a refrigerant-coolant heat exchanger and is configured to exchange heat between the refrigerant and the coolant in the coolant circuits 3a and 3b. Therefore, the refrigerant circuit 2 and the coolant circuits 3a and 3b are connected to each other in the heat pump system 1 via the refrigerant 16 in a heat transfer manner.

[0037] In addition, the refrigerant circuit 2 has a valve device 17, wherein the first sub-circuit 9a and the second sub-circuit 9b are fluidly connected to each other only through the valve device 17.

[0038] In the first sub-loop 9a, the low-pressure accumulator 10, compressor 11, heat pump heater 12, and external heat exchanger 13 are connected to each other in a fluid-guided and series manner via the first sub-loop line 18. The first sub-loop line 18 is fluid-guidedly connected to the valve device 17 at the first sub-loop inlet 18a and the first sub-loop outlet 18b. Furthermore, the external heat exchanger 13 can be bypassed via a bypass line 19. The bypass line 19 is fluid-guidedly connected to the first sub-loop line 18 at the bypass inlet 19a and to the valve device 17 at the bypass outlet 19b. In the second sub-loop 9b, the evaporator 15 and cooler 16 are connected to each other in a fluid-guided and parallel manner via the second sub-loop line 20. The second sub-loop line 20 is fluid-guidedly connected to the valve device 17 at the second sub-loop inlet 20a and the second sub-loop outlet 20b. Here in the valve device 17, the second sub-loop outlet 20b is always fluidly connected to the first sub-loop inlet 18a.

[0039] Sub-loops 9a and 9b can be interconnected in different ways via valve assembly 17, allowing the heat pump system 1 to operate in different operating modes. (Refer to the following...) Figures 2-4 A more detailed explanation of each operating mode.

[0040] The valve device 17 itself can be implemented in different ways. Figure 1 In the first embodiment, valve device 17 is shown and includes a first 2 / 1-way valve 21, a second 2 / 1-way valve 22, and a check valve 23. The first 2 / 1-way valve 21 interconnects the first sub-circuit outlet 18b and the first sub-circuit inlet 18a. The second 2 / 1-way valve 22 interconnects the bypass outlet 19b and the second sub-circuit inlet 20a. The check valve 23 fluidly connects a connection point 24 upstream of the first 2 / 1-way valve 21 and a connection point 25 downstream of the second 2 / 1-way valve 21. Furthermore, the second sub-circuit outlet 20b is fluidly connected to the first sub-circuit inlet 18a at a connection point 32 downstream of the first 2 / 1-way valve 21. The valves 21, 22, and 23 of valve device 17 can be securely connected to the low-pressure accumulator 10, or can be flanged to the low-pressure accumulator 10 respectively, thus forming a structurally integrated structural unit 33. Valve device 17 in the first embodiment also... Figure 5 As shown in the image.

[0041] Figure 2 A circuit diagram of the heat pump system 1 according to the invention in cooling mode is shown. In cooling mode, expansion valve 13a is open without throttling, and expansion valves 15a and 16a respectively form throttling valves. 2 / 1-way valves 21 and 2 / 1-way valve 22 are closed. Thus, the first sub-loop outlet 18b is fluidly connected to the second sub-loop inlet 20a via check valve 23, and the second sub-loop outlet 20b is fluidly connected to the first sub-loop inlet 18a. Bypass line 19 is closed. Figure 2 In the diagram, the non-flowing area of ​​refrigerant circuit 2 is represented by a dashed line.

[0042] The refrigerant flows through compressor 11 and is compressed. In cooling mode, heat pump heater 12 is turned off, and no heat exchange occurs between the refrigerant and the interior air IL via heat pump heater 12. Due to the closure of bypass line 19, the refrigerant flows through heat pump heater 12 and then through expansion valve 13a, which is open without throttling, into external heat exchanger 13. In external heat exchanger 13, the refrigerant releases heat to the ambient air UL and is liquefied. Subsequently, the refrigerant is guided from the first sub-loop outlet 18b via valve device 17 to the second sub-loop inlet 20a, evaporator 15, and refrigerator 16 via check valve 23. The refrigerant is throttled through expansion valves 15a and 16a and transitions to lower pressure and lower temperature. Thus, the refrigerant can evaporate in evaporator 15 and refrigerator 16, accompanied by corresponding heat absorption. As a result, the coolant in the two cooling loops 3a and 3b is cooled in refrigerator 16, and the interior air IL of air conditioning system 14 is cooled in evaporator 15. Subsequently, the refrigerant flows from the refrigerator 16 and evaporator 15 to the second sub-loop outlet 20b, and is guided through the valve device 17 to the second sub-loop inlet 18a, thereby being guided into the first sub-loop 9a.

[0043] Figure 3 A circuit diagram of the heat pump system 1 according to the invention is shown in a first heating mode. In the first heating mode, expansion valves 13a and 16a each form throttling valves. Expansion valve 15a is closed. 2 / 1-way valves 21 and 2 / 1-way valve 22 are open. Thus, bypass outlet 19b is fluidly connected to the second sub-loop inlet 20a. Furthermore, the first sub-loop outlet 18b and the second sub-loop outlet 20b are fluidly connected to the first sub-loop inlet 18a. Figure 3 In the diagram, the non-flowing region of refrigerant circuit 2 is represented by a dashed line.

[0044] The refrigerant flows through compressor 11 and is compressed. Thereafter, the refrigerant flows under high pressure and high temperature into heat pump heater 12. Heat pump heater 12 acts as a condenser, where the refrigerant condenses and dissipates heat to the interior air 1L. The refrigerant then flows further to bypass inlet 19a. When expansion valve 13a forms a throttling valve and bypass line 19 opens, the refrigerant is diverted at bypass inlet 19a. A first portion of the refrigerant flows via bypass line 19 and is guided through valve device 17 to second sub-loop inlet 20a. This first portion of the refrigerant is then throttled through expansion valve 16a and evaporates in refrigerator 16, accompanied by corresponding heat absorption. Thus, the refrigerant in coolant loops 3a and 3b is cooled. Evaporator 15 is not flowed through here. Subsequently, the refrigerant flows to second sub-loop outlet 20b and is guided through valve device 17 to first sub-loop inlet 18a, and further into first sub-loop 9a. The second portion of the refrigerant is throttled through expansion valve 13a and subsequently evaporated in external heat exchanger 13. Afterward, the refrigerant flows to the first sub-loop outlet 18b. Due to the pressure difference, check valve 23 remains closed, and the refrigerant flows to the first sub-loop inlet 18a and further into the first sub-loop 9a.

[0045] Figure 4 A circuit diagram of the heat pump system 1 according to the invention in a second heating mode is shown. In the second heating mode, expansion valve 13a and expansion valve 15a at the evaporator are closed. Expansion valve 16a forms a throttling valve. 2 / 1-way valve 21 is closed, and 2 / 1-way valve 22 is open. Thus, bypass outlet 19b is fluidly connected to the second sub-loop inlet 20a. Figure 4 In the diagram, the non-flowing region of refrigerant circuit 2 is represented by a dashed line.

[0046] In the second heating mode, expansion valve 13a closes, thereby closing the first sub-loop outlet 18b. Compared to the first heating mode, all refrigerant flows to the bypass outlet 19b via bypass line 19. Furthermore, the second heating mode corresponds to... Figure 3 The first heating mode.

[0047] Figure 5 A view of the valve device 17 in the first embodiment of structural unit 33 is shown. (See reference...) Figures 2-4 As detailed in the description, the valve device 17 of the first embodiment has two 2 / 1-way valves 21 and 22 and a check valve 23. To avoid repetition, please refer to the above notes here. The valves 21, 22 and 23 of the valve device 17 are connected to the low-pressure accumulator 10 by flanges, thereby forming a structurally integrated structural unit 33.

[0048] Figure 6A view of valve device 17 in the second embodiment of structural unit 33 is shown. Valve device 17 here has a 2 / 1-way valve 26 and a 3 / 2-way valve 27. The 2 / 1-way valve 26 interconnects the bypass outlet 19b and the second sub-loop inlet 20a with each other. The 3 / 2-way valve 27 interconnects the first sub-loop outlet 18b, the first sub-loop inlet 18a, and a connection point 28 located downstream of the 2 / 1-way valve 26 with each other at the second sub-loop line 20. Furthermore, the second sub-loop outlet 20b is fluidly connected to the first sub-loop inlet 18a at a connection point 29 located downstream of the 3 / 2-way valve 27.

[0049] Figure 7 A view of valve device 17 in a third embodiment of structural unit 33 is shown. Valve device 17 here has a 4-way valve 30. The 4-way valve 30 interconnects the first sub-loop outlet 18b, the first sub-loop inlet 18a, the bypass outlet 19b, and the second sub-loop inlet 20a with each other. In addition, the second sub-loop outlet 20b is fluidly connected to the first sub-loop inlet 18a at a connection point 31 located downstream of the 4-way valve 30.

[0050] It should be understood that the above Figures 2-4 The operating mode described herein can be used in conjunction with Figures 5-7 The valve device 17 shown in the embodiment is implemented in the same manner.

Claims

1. A heat pump system for motor vehicles (1). -in, The heat pump system (1) has a refrigerant circuit (2) through which the refrigerant can flow. -The refrigerant circuit (2) has a first sub-circuit (9a), which has a low-pressure accumulator (10), a compressor (11), a heat pump heater (12) and an external heat exchanger (13). -The refrigerant circuit (2) has a second sub-circuit (9b), which has an evaporator (15) and a refrigerant (16). Its features The refrigerant circuit (2) has a valve device (17), and the first sub-circuit (9a) and the second sub-circuit (9b) are fluidly connected to each other only through the valve device (17).

2. The heat pump system according to claim 1, Its features In the first sub-loop (9a), the low-pressure accumulator (10), compressor (11), heat pump heater (12), and external heat exchanger (13) are connected to each other in a fluid-guided and series manner via the first sub-loop pipeline (18). - The first sub-loop line (18) is fluid-guidedly connected to the valve device (17) at the first sub-loop inlet (18a) located upstream of the low-pressure accumulator (10) and at the first sub-loop outlet (18b) located downstream of the external heat exchanger (13). - In the first sub-loop (9a), the external heat exchanger (13) can be bypassed via the bypass line (19), and - The bypass line (19) is connected to the first sub-loop line (18) at a bypass inlet (19a) located upstream of the external heat exchanger (13) in a fluid-guided manner, and is connected to the valve device (17) at a bypass outlet (19b).

3. The heat pump system according to claim 2, Its features are: - In the second sub-loop (9b), the evaporator (15) and the cooler (16) are connected to each other in a fluid-guided and parallel manner via the second sub-loop line (20), and - The second sub-loop line (20) is fluid-guidedly connected to the valve device (17) at the second sub-loop inlet (20a) located upstream of the evaporator (15) and the refrigerator (16) and at the second sub-loop outlet (20b) located downstream of the evaporator (15) and the refrigerator (16).

4. The heat pump system according to claim 3, Its features are: -The heat pump system (1) has an adjustable expansion valve (13a) directly arranged upstream of the external heat exchanger (13), and / or -The heat pump system has an adjustable expansion valve (15a) directly arranged upstream of the evaporator (15), and / or - The heat pump system (1) has an adjustable expansion valve (16a) directly arranged upstream of the cooler (16).

5. The heat pump system according to claim 4, Its features are: -The heat pump system (1) is capable of operating in cooling mode. - In cooling mode, the expansion valve (13a) at the external heat exchanger (13) opens without throttling; and the expansion valve (15a) at the evaporator (15) and the expansion valve (16a) at the refrigerator (16) respectively form throttling valves. - In cooling mode, the bypass line (19) in the first sub-circuit (9a) is closed via the valve device (17); the outlet (18b) of the first sub-circuit is fluidly connected to the inlet (20a) of the second sub-circuit; the outlet (20b) of the second sub-circuit is fluidly connected to the inlet (18a) of the first sub-circuit.

6. The heat pump system according to any one of claims 4 to 5, Its features are: -The heat pump system (1) is capable of operating in the first heating mode. - In the first heating mode, the expansion valve (13a) at the external heat exchanger (13) and the expansion valve (16a) at the refrigerator (16) respectively form throttling valves; and the expansion valve (15a) at the evaporator (15) is closed. - In the first heating mode, the bypass outlet (19b) is fluidly connected to the second sub-circuit inlet (20a) via the valve device (17); and the first sub-circuit outlet (18b) and the second sub-circuit outlet (20b) are fluidly connected to the first sub-circuit inlet (18a).

7. The heat pump system according to any one of claims 4 to 5, Its features are: -The heat pump system (1) is capable of operating in a second heating mode. - In the second heating mode, the expansion valve (13a) at the external heat exchanger (13) is closed, thereby closing the first sub-loop outlet (18b); the expansion valve (15a) at the evaporator (15) is closed; and the expansion valve (16a) at the refrigerator (16) forms a throttling valve. - In the second heating mode, the bypass outlet (19b) is fluidly connected to the second sub-circuit inlet (20a) via the valve device (17); and the second sub-circuit outlet (20b) is fluidly connected to the first sub-circuit inlet (18a).

8. The heat pump system according to any one of claims 3 to 5, Its features are: -The valve device (17) has a first 2 / 1-way valve (21), a second 2 / 1-way valve (22), and a check valve (23), and - The first 2 / 1 through valve (21) interconnects the first sub-circuit outlet (18b) and the first sub-circuit inlet (18a) with each other, and - The second 2 / 1 through valve (22) interconnects the bypass outlet (19b) and the second sub-circuit inlet (20a) with each other, and -The check valve (23) fluidly connects the connection point (24) located upstream of the first 2 / 1-way valve (21) and the connection point (25) located downstream of the second 2 / 1-way valve (22), and - The second sub-circuit outlet (20b) is fluidly connected to the first sub-circuit inlet (18a) at a connection point (33) located downstream of the first 2 / 1 through valve (21).

9. The heat pump system according to any one of claims 3 to 5, Its features are: -The valve device (17) has a 2 / 1-way valve (26) and a 3 / 2-way valve (27), and - The 2 / 1 through valve (26) interconnects the bypass outlet (19b) and the second sub-circuit inlet (20a) with each other, and - The 3 / 2-way valve (27) interconnects the first sub-circuit outlet (18b), the first sub-circuit inlet (18a), and the connection point (28) located downstream of the 2 / 1-way valve (26) with each other. - The second sub-circuit outlet (20b) is fluidly connected to the first sub-circuit inlet (18a) at a connection point (29) located downstream of the 3 / 2-way valve (27).

10. The heat pump system according to any one of claims 3 to 5, Its features are: -The valve device (17) has a 4-way valve (30). - The 4-way valve (30) interconnects the first sub-circuit outlet (18b), the first sub-circuit inlet (18a), the bypass outlet (19b), and the second sub-circuit inlet (20a) with each other, and - The second sub-circuit outlet (20b) is fluidly connected to the first sub-circuit inlet (18a) at a connection point (31) located downstream of the 4-way valve (30).

11. The heat pump system according to any one of claims 1 to 5, Its features are: The valve device (17) is securely connected to the low-pressure accumulator (10), thereby forming a separate structurally integrated structural unit (33).

12. The heat pump system according to claim 1, Its features are: - In the second sub-loop (9b), the evaporator (15) and the cooler (16) are connected to each other in a fluid-guided and parallel manner via the second sub-loop line (20), and - The second sub-loop line (20) is fluid-guidedly connected to the valve device (17) at the second sub-loop inlet (20a) located upstream of the evaporator (15) and the refrigerator (16) and at the second sub-loop outlet (20b) located downstream of the evaporator (15) and the refrigerator (16).

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