Heat pump system and method, device and vehicle for controlling refrigerant recirculation thereof

Abstract

The application discloses a heat pump system, a refrigerant backflow control method and device thereof and a vehicle. The heat pump system comprises a first refrigerant circuit, a second refrigerant circuit and an on-off valve. The method comprises the following steps: in response to a heating mode instruction, controlling the on-off valve to make the first refrigerant circuit heat a target area; acquiring a high-pressure pressure of the first refrigerant circuit; when the high-pressure pressure is greater than a first preset pressure threshold, controlling the on-off valve to make the second refrigerant circuit and the first refrigerant circuit be connected in series, so as to heat the target area through the second refrigerant circuit and the first refrigerant circuit. The method of the application can realize twice heating of the target area by controlling the on-off valve, thereby improving the heat exchange efficiency of the heat pump system, reducing the energy consumption of the system, and avoiding refrigerant backflow.

Description

Technical Field

[0001] This invention relates to the field of vehicle technology, and in particular to a refrigerant reflux control method for a heat pump system, a heat pump system, a refrigerant reflux control device for a heat pump system, and a vehicle. Background Technology

[0002] Currently, the market share of new energy electric vehicles is gradually increasing. In order to improve the energy utilization rate of electric vehicles and reduce the overall power consumption, more and more electric vehicles are equipped with heat pump systems as standard.

[0003] In related technologies, heat pump systems are equipped with compressor hot gas bypass valves. When such heat pump systems start in low-temperature environments (such as below -15°C), the compressor starts cold. When the compressor heat pump bypass valve is opened, as the compressor speed increases, the heat gradually increases, and the low-pressure will be higher than 1.6 bar. Because the evaporator inlet air temperature is low, the pressure at the evaporator is low, and the refrigerant flows back to the evaporator, resulting in insufficient refrigerant in the main circuit, affecting system operation and reducing the system's heat exchange efficiency. Summary of the Invention

[0004] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, the first objective of this invention is to provide a refrigerant backflow control method for a heat pump system, which can achieve double heating of the target area by controlling the on / off valve, thereby improving the heat exchange efficiency of the heat pump system, reducing system energy consumption, and preventing refrigerant backflow.

[0005] The second objective of this invention is to provide a heat pump system.

[0006] The third objective of this invention is to provide a refrigerant reflux control device for a heat pump system.

[0007] The fourth objective of this invention is to provide a vehicle.

[0008] To achieve the above objectives, a first aspect of the present invention provides a refrigerant reflux control method for a heat pump system. The heat pump system includes a first refrigerant circuit, a second refrigerant circuit, and an on / off valve. The method includes: responding to a heating mode command, controlling the on / off valve to heat a target area using the first refrigerant circuit; acquiring the high-pressure of the first refrigerant circuit; and when the high-pressure is greater than a first preset pressure threshold, controlling the on / off valve to connect the second refrigerant circuit in series with the first refrigerant circuit, so as to heat the target area through the second refrigerant circuit and the first refrigerant circuit.

[0009] According to an embodiment of the present invention, a refrigerant backflow control method for a heat pump system first responds to a heating mode command by controlling an on / off valve to heat a target area using a first refrigerant circuit. Then, it acquires the high-pressure of the first refrigerant circuit, and when the high-pressure exceeds a first preset pressure threshold, it controls the on / off valve to connect a second refrigerant circuit in series with the first refrigerant circuit, thereby heating the target area through both the second and first refrigerant circuits. Thus, this method can achieve two heating cycles for the target area by controlling the on / off valve, thereby improving the heat exchange efficiency of the heat pump system, reducing system energy consumption, and preventing refrigerant backflow.

[0010] In addition, the refrigerant reflux control method for the heat pump system according to the above embodiments of the present invention may also have the following additional technical features:

[0011] According to one embodiment of the present invention, the on / off valve includes a first on / off valve, a second on / off valve, and a third on / off valve. The first refrigerant circuit includes a compressor, a first heat exchanger, a first throttling element, and a second heat exchanger. The second refrigerant circuit includes a second throttling element and a third heat exchanger. The discharge port of the compressor is connected to a first end of the first heat exchanger. The second end of the first heat exchanger is connected to one end of the first on / off valve and one end of the second on / off valve, respectively. The other end of the first on / off valve is connected to one end of the first throttling element and one end of the second throttling element, respectively. The other end of the first throttling element is connected to the first end of the second heat exchanger. The other end of the second throttling element is connected to the second on / off valve via the third heat exchanger. The other end of the shut-off valve is connected to one end of the third shut-off valve, and the second end of the second heat exchanger and the other end of the third shut-off valve are respectively connected to the suction port of the compressor; wherein, controlling the shut-off valve to connect the second refrigerant circuit in series with the first refrigerant circuit to heat the target area through the second refrigerant circuit and the first refrigerant circuit includes: controlling the second shut-off valve to be in the open state and the first shut-off valve and the third shut-off valve to be in the closed state, so that the second refrigerant circuit and the first refrigerant circuit are connected in series; controlling the second throttling element, the first throttling element and the compressor to be in the open state, so as to heat the target area through the second refrigerant circuit and the first refrigerant circuit.

[0012] According to one embodiment of the present invention, controlling the on / off valve to heat the target area by the first refrigerant circuit includes: controlling the second on / off valve to be in a closed state, the first on / off valve to be in an open state, the third on / off valve to be in an open or closed state, and controlling the first throttling element and the compressor to be in an open state, so as to heat the target area through the first refrigerant circuit.

[0013] According to one embodiment of the present invention, the first refrigerant circuit further includes a third throttling element, the two ends of which are correspondingly connected to the discharge port and suction port of the compressor; wherein, during cold start of the compressor, the method further includes: controlling the opening degree of the third throttling element to make the suction superheat of the compressor greater than a preset suction superheat, and controlling the first throttling element to be in an open state when the suction superheat is greater than the preset suction superheat.

[0014] According to an embodiment of the present invention, the method further includes: in response to a cooling mode command, controlling the second on-off valve to be in a closed state, the first on-off valve and the third on-off valve to be in an open state, and controlling the second throttling element and the compressor to be in an open state, so as to cool the target area.

[0015] According to one embodiment of the present invention, the heat pump system further includes a battery heat exchange circuit for exchanging heat with the battery, the battery heat exchange circuit being connected to the first refrigerant circuit. When cooling the target area, the method further includes: obtaining the cooling demand of the battery; and controlling the first refrigerant circuit based on the cooling demand of the battery, so that the first refrigerant circuit cools the battery through the battery heat exchange circuit.

[0016] According to one embodiment of the present invention, controlling the first refrigerant circuit based on the cooling demand of the battery to cool the battery through the battery heat exchange circuit includes: controlling the opening degree of the first throttling element based on the cooling demand of the battery to allow the second heat exchanger to exchange heat with the battery heat exchange circuit to cool the battery through the battery heat exchange circuit.

[0017] To achieve the above objectives, a second aspect of the present invention provides a heat pump system, comprising: a memory, a processor, and a program stored in the memory and executable on the processor, wherein when the processor executes the program, it implements the refrigerant reflux control method of the heat pump system described above.

[0018] According to the heat pump system of the present invention, the refrigerant backflow control method of the heat pump system described above can achieve double heating of the target area by controlling the on / off valve, thereby improving the heat exchange efficiency of the heat pump system, reducing the energy consumption of the system, and avoiding refrigerant backflow.

[0019] To achieve the above objectives, a third aspect of the present invention provides a refrigerant reflux control device for a heat pump system. The heat pump system includes a first refrigerant circuit, a second refrigerant circuit, and an on / off valve. The device includes: a control module, configured to control the on / off valve to heat a target area via the first refrigerant circuit in response to a heating mode command; an acquisition module, configured to acquire the high-pressure of the first refrigerant circuit; and the control module is further configured to control the on / off valve to connect the second refrigerant circuit in series with the first refrigerant circuit when the high-pressure is greater than a first preset pressure threshold, so as to heat the target area through the second refrigerant circuit and the first refrigerant circuit.

[0020] According to an embodiment of the present invention, a refrigerant backflow control device for a heat pump system includes a control module that, in response to a heating mode command, controls an on / off valve to heat a target area via a first refrigerant circuit. An acquisition module acquires the high-pressure value of the first refrigerant circuit. Furthermore, when the high-pressure value exceeds a first preset pressure threshold, the control module controls the on / off valve to connect a second refrigerant circuit in series with the first refrigerant circuit, thereby heating the target area through both the second and first refrigerant circuits. Thus, this device can achieve two heating cycles for the target area by controlling the on / off valve, thereby improving the heat exchange efficiency of the heat pump system, reducing system energy consumption, and preventing refrigerant backflow.

[0021] To achieve the above objectives, a fourth aspect of the present invention provides a vehicle including a refrigerant recirculation control device for the heat pump system described above.

[0022] According to the vehicle of the present invention, the refrigerant backflow control device of the heat pump system described above can control the on / off valve to achieve double heating of the target area, thereby improving the heat exchange efficiency of the heat pump system, reducing the energy consumption of the system, and preventing refrigerant backflow.

[0023] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0024] Figure 1 A flowchart of a refrigerant reflux control method for a heat pump system according to an embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of a heat pump system according to an embodiment of the present invention;

[0026] Figure 3 This is a schematic diagram of the structure of a heat pump system in related technologies;

[0027] Figure 4This is a block diagram of a heat pump system according to an embodiment of the present invention;

[0028] Figure 5 This is a block diagram of a refrigerant reflux control device for a heat pump system according to an embodiment of the present invention;

[0029] Figure 6 This is a block diagram of a vehicle according to an embodiment of the present invention.

[0030] Figure label:

[0031] First refrigerant circuit 10; compressor 11; first heat exchanger 12; first throttling element 13; second heat exchanger 14; third throttling element 15;

[0032] Second refrigerant circuit 20; Second throttling element 21; Third heat exchanger 22;

[0033] Heating circuit 30; Nine-way valve 40; Three-way valve 50; Battery heat exchange circuit 60; Electric drive heat exchange circuit 70; Ambient heat exchange circuit 80;

[0034] On / off valve 90; First on / off valve SOV1; Second on / off valve SOV2; Third on / off valve SOV3;

[0035] Heat pump system 200; memory 210; processor 220;

[0036] Low-temperature control device 100 for heat pump system; first control module 110; second control module 120;

[0037] Vehicle 300. Detailed Implementation

[0038] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0039] The following description, with reference to the accompanying drawings, illustrates the refrigerant reflux control method for a heat pump system, the heat pump system, the refrigerant reflux control device for the heat pump system, and the vehicle proposed in embodiments of the present invention.

[0040] Figure 1 This is a flowchart of a refrigerant reflux control method for a heat pump system according to an embodiment of the present invention.

[0041] like Figure 2As shown, the heat pump system includes a first refrigerant circuit 10, a second refrigerant circuit 20, and an on / off valve 90. The flow direction of the refrigerant in the first refrigerant circuit 10 and the second refrigerant circuit 20 can be adjusted by controlling the opening or closing of the on / off valve 90.

[0042] like Figure 1 As shown, the refrigerant reflux control method for a heat pump system according to an embodiment of the present invention may include the following steps:

[0043] S1, in response to the heating mode command, controls the on / off valve to enable the first refrigerant circuit to heat the target area.

[0044] When the heat pump system is installed in the vehicle, the target area is the passenger compartment.

[0045] S2, obtain the high pressure of the first refrigerant circuit.

[0046] The high pressure of the first refrigerant circuit can be obtained by a pressure sensor installed on the high-pressure side of the first refrigerant circuit.

[0047] S3, when the high pressure exceeds the first preset pressure threshold, the on / off valve is controlled to connect the second refrigerant circuit in series with the first refrigerant circuit, so as to heat the target area through the second refrigerant circuit and the first refrigerant circuit. The first preset pressure threshold can be calibrated according to actual conditions.

[0048] Specifically, in colder environments, such as northern winters, users may issue a heating command when using the vehicle. Upon receiving this command, the heat pump system controller activates the on / off valve to heat the passenger compartment via the first refrigerant circuit. The controller uses a pressure sensor on the high-pressure side of the first refrigerant circuit to continuously monitor its pressure. This pressure is compared to a preset pressure threshold. When the pressure exceeds this threshold, the controller connects the second and third refrigerant circuits in series. This allows the warmer refrigerant from the first circuit to provide secondary heating to the target area via the second circuit, releasing its heat before flowing back into the first circuit. Thus, by controlling the on / off valve, the target area can be heated twice, improving the heat exchange efficiency of the heat pump system, reducing energy consumption, and preventing refrigerant backflow.

[0049] In one embodiment of the present invention, such as Figure 2As shown, the heat pump system includes a first refrigerant circuit 10, a second refrigerant circuit 20, and an on / off valve 90. The on / off valve 90 includes a first on / off valve SOV1, a second on / off valve SOV2, and a third on / off valve SOV3. The first refrigerant circuit 10 includes a compressor 11, a first heat exchanger 12, a first throttling element 13, and a second heat exchanger 14. The second refrigerant circuit 20 includes a second throttling element 21 and a third heat exchanger 22. The exhaust port of the compressor 11 is connected to the first end of the first heat exchanger 12, and the second end of the first heat exchanger 12 is connected to the first on / off valve SOV3. One end of the shut-off valve SOV1 is connected to one end of the second shut-off valve SOV2. The other end of the first shut-off valve SOV1 is connected to one end of the first throttling element 13 and one end of the second throttling element 21, respectively. The other end of the first throttling element 13 is connected to the first end of the second heat exchanger 14. The other end of the second throttling element 21 is connected to the other end of the second shut-off valve SOV2 and one end of the third shut-off valve SOV3 through the third heat exchanger 22, respectively. The second end of the second heat exchanger 14 and the other end of the third shut-off valve SOV3 are connected to the suction port of the compressor 11, respectively. The first heat exchanger 12 can be a water-cooled condenser, the first throttling element 13 and the second throttling element 21 can be expansion valves, and the third heat exchanger 22 can be an evaporator. The heat pump system also includes a heating circuit 30, a battery heat exchange circuit 60, an electric drive heat exchange circuit 70, and an ambient heat exchange circuit 80. When the heat replenishment capacity is sufficient, it means that the current heat pump circuit 10 has enough heat to provide heat to the heating circuit 30. Therefore, the remaining heat can be released to one or more of the battery heat exchange circuit 60, the electric drive heat exchange circuit 70, and the ambient heat exchange circuit 80. When the heat replenishment capacity is insufficient, the heating circuit 30 or the heat pump circuit 10 can be controlled to absorb heat from at least one of the battery heat exchange circuit 60, the electric drive heat exchange circuit 70, and the ambient heat exchange circuit 80 to replenish heat to the passenger compartment. In other words, when the heat replenishment capacity is insufficient, it means that the current heat pump circuit 10 does not have enough heat to provide heat to the heating circuit 30. Therefore, heat can be released to the heating circuit 30 through one or more of the battery heat exchange circuit 60, the electric drive heat exchange circuit 70, and the ambient heat exchange circuit 80, increasing the refrigerant temperature in the heating circuit 30 to replenish heat to the passenger compartment. The system can also release heat to the heat pump circuit 10 through one or more of the battery heat exchange circuit 60, electric drive heat exchange circuit 70, and ambient heat exchange circuit 80, and provide heat to the heating circuit to supplement the crew compartment. The heat pump system also includes a nine-way valve 40 and a three-way valve 50, which are connected to the battery heat exchange circuit 60, electric drive heat exchange circuit 70, and ambient heat exchange circuit 80. By controlling the nine-way valve 40 and the three-way valve 50, the system can control the heat pump circuit 10 to provide heat to the heating circuit 30 to supplement the crew compartment, and control the heating circuit 30 to absorb heat from the battery heat exchange circuit 60 or the electric drive heat exchange circuit 70, or release heat to at least one of the battery heat exchange circuit 60, the electric drive heat exchange circuit 70, and the ambient heat exchange circuit 80.

[0050] It should be noted that the heat pump system in the relevant technology, such as Figure 3 As shown, Figure 3 The heat pump system shown is Figure 2 A comparison of the heat pump systems shown reveals that... Figure 2 The heat pump system shown lacks the first on / off valve SOV1, the second on / off valve SOV2, and the third on / off valve SOV3. During heating, if the pressure at the suction port of compressor 11 exceeds the saturation pressure of the refrigerant in the third heat exchanger 22, the refrigerant will flow back to the third heat exchanger 22, resulting in insufficient refrigerant in the first refrigerant circuit 10 and affecting system operation. Figure 3 The heat pump system shown connects the second refrigerant circuit 20 and the first refrigerant circuit 10 in series by controlling the on / off valve. This allows the target area to be heated through both the second refrigerant circuit 20 and the first refrigerant circuit 10, preventing refrigerant from flowing back to the third heat exchanger. The following describes, with reference to a specific embodiment, how to control the on / off valve 90 to connect the second refrigerant circuit 20 and the first refrigerant circuit 10 in series.

[0051] According to one embodiment of the present invention, controlling the on-off valve to connect the second refrigerant circuit in series with the first refrigerant circuit to heat a target area through the second refrigerant circuit and the first refrigerant circuit includes: controlling the second on-off valve to be in an open state and the first on-off valve and the third on-off valve to be in a closed state, so that the second refrigerant circuit and the first refrigerant circuit are connected in series; controlling the second throttling element, the first throttling element and the compressor to be in an open state, so as to heat the target area through the second refrigerant circuit and the first refrigerant circuit.

[0052] Specifically, when the heat pump system controller receives a heating command, it controls the compressor to start operating and the first throttling element to open. This allows the liquid refrigerant, in a low-temperature, low-pressure state, to be transformed into a high-temperature, high-pressure gaseous refrigerant, which is then delivered to the first heat exchanger through the compressor's exhaust port. The high-temperature, high-pressure gaseous refrigerant releases heat to the water in the first heat exchanger, heating it. The heating circuit then transfers this heat to the passenger compartment to heat it. The controller uses a pressure sensor located at the compressor exhaust port to acquire the high-pressure reading in real time and compares it with a first preset pressure threshold. When the high-pressure reading exceeds the first preset threshold, the controller controls the second throttling element to open and the second on / off valve to open, while the first and third on / off valves close. At this time, the second refrigerant circuit is connected in series with the first refrigerant circuit. The refrigerant, still carrying heat, flows from the first heat exchanger through the second on / off valve into the third heat exchanger for heat exchange, heating the air around the third heat exchanger. This heat is then blown into the passenger compartment by a fan for secondary heating of the passenger compartment. The refrigerant flowing from the third heat exchanger sequentially passes through the second throttling element and then into the second heat exchanger to absorb heat from one or more of the battery heat exchange circuit, electric drive heat exchange circuit, and ambient heat exchange circuit. It then flows into the compressor, thus simultaneously heating the target area through both the second and first refrigerant circuits. This allows for two heating cycles of the target area, improving the overall system's heat exchange efficiency, reducing energy consumption, and by using the third heat exchanger as a secondary heat exchange device, the refrigerant flows and heats the target area simultaneously, preventing refrigerant from flowing back into the third heat exchanger.

[0053] According to one embodiment of the present invention, controlling the on-off valve to heat the target area by the first refrigerant circuit includes: controlling the second on-off valve to be in a closed state, the first on-off valve to be in an open state, the third on-off valve to be in an open or closed state, and controlling the first throttling element and the compressor to be in an open state, so as to heat the target area through the first refrigerant circuit.

[0054] Specifically, when the heat pump system controller receives a heating command, it controls the compressor to start, the first throttling element to open, and the second throttling element to close. It also controls the first on-off valve to open and the second on-off valve to close, so that the liquid refrigerant in the low temperature and low pressure state is transformed into a gaseous refrigerant in the high temperature and high pressure state by the compressor. The gaseous refrigerant in the high temperature and high pressure state is then delivered to the first heat exchanger through the compressor's exhaust port. The gaseous refrigerant in the high temperature and high pressure state releases heat to the water in the first heat exchanger, thereby heating the water in the first heat exchanger. The heating circuit can transfer the heat from the first heat exchanger to the passenger compartment to heat the passenger compartment. The refrigerant flowing out of the first heat exchanger flows into the second heat exchanger through the first on-off valve and the first throttling element, and then flows into the compressor, thus completing the heating of the target area through the first refrigerant circuit. It should be noted that during the process of heating the target area through the first refrigerant circuit, when the third on-off valve is open, if the pressure at the compressor suction port is greater than the saturation pressure of the refrigerant in the third heat exchanger, a small amount of refrigerant may flow back from the compressor suction port to the third heat exchanger. However, this situation does not occur when the third on-off valve is closed.

[0055] Furthermore, as the compressor operates, the high pressure at the compressor discharge port gradually increases. The controller acquires the high pressure in real time through a pressure sensor located at the compressor discharge port. When the high pressure exceeds a first preset pressure threshold, the controller controls the second on-off valve to open, the first on-off valve and the third on-off valve to close, and controls the second throttling element to open. At this time, the second refrigerant circuit is connected in series with the first refrigerant circuit. The refrigerant, still carrying heat, flowing out of the first heat exchanger flows through the second on-off valve into the third heat exchanger for heat exchange, heating the air around the third heat exchanger. This heat is then blown into the passenger compartment by a fan for secondary heating of the passenger compartment. The refrigerant flowing out of the third heat exchanger flows sequentially through the second throttling element into the second heat exchanger to absorb heat from one or more of the battery heat exchange circuit, the electric drive heat exchange circuit, and the environmental heat exchange circuit before flowing into the compressor. As secondary heat exchange proceeds, the compressor's heating power decreases, and the high-pressure pressure decreases accordingly. When the high-pressure pressure is less than the second preset pressure threshold (which can be 12 bar), the controller controls the second throttling element to close and controls the first on / off valve to open, the second on / off valve to close, and the third on / off valve to open or close. This switches the state of heating the target area through the second refrigerant circuit and the first refrigerant circuit to the state of heating the target area through the first refrigerant circuit, thereby avoiding the situation where the compressor's heating power is too low.

[0056] According to one embodiment of the present invention, such as Figure 2As shown, the first refrigerant circuit 10 also includes a third throttling element 15, the two ends of which are connected to the discharge port and suction port of the compressor 11 respectively. During cold start of the compressor, the method further includes: controlling the opening degree of the third throttling element to make the suction superheat of the compressor greater than a preset suction superheat, and controlling the first throttling element to be in the open state when the suction superheat is greater than the preset suction superheat. The preset suction superheat can be calibrated according to actual conditions.

[0057] Specifically, in low-temperature environments requiring heating, the compressor's body temperature is low upon initial startup, the suction port pressure is low, and there is no overheating at the suction port. To avoid triggering the compressor's low-pressure protection, a cold start is necessary. During a cold start, the controller adjusts the opening of the third throttling element to its maximum, closes the first and second throttling elements, and controls the compressor to operate at a lower speed. The refrigerant flows from the discharge port and enters the suction port through the third throttling element, where it is heated by the compressor's own heat, gradually increasing the suction pressure. When the suction pressure is high, the opening of the third throttling element is appropriately reduced to lower the suction pressure. As the compressor operates, the temperature at the compressor suction port also rises. The controller uses a temperature sensor located at the compressor inlet to monitor the suction port temperature in real time and a pressure sensor to obtain the current refrigerant pressure at the suction port. The controller then uses a lookup table to determine the saturation temperature corresponding to the current pressure. The controller calculates the suction superheat based on the temperature and saturation temperature of the compressor suction port and compares the suction superheat with the preset suction superheat. When the suction superheat is greater than the preset suction superheat, the controller controls the first throttling element to open.

[0058] According to one embodiment of the present invention, the method further includes: in response to a cooling mode command, controlling the second on-off valve to be in a closed state, the first on-off valve and the third on-off valve to be in an open state, and controlling the second throttling element and the compressor to be in an open state, so as to cool the target area.

[0059] Specifically, when a user needs to cool the passenger compartment, they can issue a cooling mode command. Upon receiving the command, the controller closes the second on-off valve and opens the first and third on-off valves, opens the second throttling element, and starts the compressor. The high-temperature, high-pressure gaseous refrigerant output from the compressor passes through the first heat exchanger, transforming into a low-temperature, low-pressure liquid refrigerant. This liquid refrigerant then flows into the third heat exchanger through the first on-off valve and the second throttling element. In the third heat exchanger, the refrigerant exchanges heat with the surrounding air, absorbing heat to lower the ambient air temperature. The refrigerant is then blown into the passenger compartment by a fan, thus cooling the passenger compartment. It's important to understand that in related technologies, to prevent refrigerant backflow, a one-way valve is typically installed at the outlet of the third heat exchanger (evaporator). However, the pressure drop of the one-way valve is significant, leading to higher evaporator pressure during cooling and poorer cooling effect in the passenger compartment. Therefore, the method described in the above embodiment ensures effective cooling of the passenger compartment without requiring a one-way valve at the evaporator outlet, saving costs.

[0060] According to one embodiment of the present invention, the heat pump system further includes a battery heat exchange circuit for exchanging heat with the battery, the battery heat exchange circuit being connected to a first refrigerant circuit. When cooling a target area, the method further includes: obtaining the cooling demand of the battery; and controlling the first refrigerant circuit based on the cooling demand of the battery so that the first refrigerant circuit cools the battery through the battery heat exchange circuit.

[0061] Furthermore, according to one embodiment of the present invention, controlling the first refrigerant circuit based on the cooling demand of the battery, so that the first refrigerant circuit cools the battery through the battery heat exchange circuit, includes: controlling the opening degree of the first throttling element based on the cooling demand of the battery, so that the second heat exchanger exchanges heat with the battery heat exchange circuit, so as to cool the battery through the battery heat exchange circuit.

[0062] Specifically, during vehicle cooling operation, the controller can obtain the battery temperature in real time through a temperature sensor located at the battery. When the battery temperature exceeds a certain value (e.g., 38°C), it determines that the battery needs cooling. The controller then controls the first throttling element to open, and the third heat exchanger is connected in parallel with the second heat exchanger. Low-temperature, low-pressure liquid refrigerant flows into the third heat exchanger through the first on / off valve and the second throttling element to cool the passenger compartment. At the same time, it also flows into the second heat exchanger through the first throttling element, so that the second heat exchanger exchanges heat with the battery heat exchange circuit through the nine-way valve, reducing the temperature of the coolant in the battery heat exchange circuit. The low-temperature coolant in the battery heat exchange circuit flows through the battery to cool it. It's important to understand that the opening degree of the first throttling element can be adjusted according to the battery temperature. For example, when the battery temperature is relatively high (e.g., 50°C), the opening degree of the first throttling element can be adjusted to its maximum to increase the heat exchange with the battery heat exchange circuit, thereby rapidly cooling the battery and preventing safety accidents caused by overheating. When the battery temperature is not particularly high (e.g., 42°C), the opening degree of the first throttling element can be adjusted to one-third of its maximum opening to further cool the battery. This allows for simultaneous cooling of the passenger compartment and timely cooling of the battery, improving vehicle safety.

[0063] In one embodiment of the present invention, such as Figure 2 As shown, a liquid storage tank is provided between the first heat exchanger 12 and the on / off valve 90.

[0064] In summary, the refrigerant backflow control method for a heat pump system according to an embodiment of the present invention first responds to a heating mode command by controlling an on / off valve to heat the target area using a first refrigerant circuit. Then, it acquires the high-pressure of the first refrigerant circuit, and when the high-pressure exceeds a first preset pressure threshold, it controls the on / off valve to connect a second refrigerant circuit in series with the first refrigerant circuit, thereby heating the target area through both the second and first refrigerant circuits. Thus, this method can achieve two heating cycles for the target area by controlling the on / off valve, thereby improving the heat exchange efficiency of the heat pump system, reducing system energy consumption, and preventing refrigerant backflow.

[0065] Corresponding to the above embodiments, the present invention also proposes a heat pump system.

[0066] Figure 4 This is a block diagram of a heat pump system according to an embodiment of the present invention.

[0067] like Figure 4 As shown, the heat pump system 200 of this embodiment includes: a memory 210, a processor 220, and a program stored in the memory 210 and executable on the processor 220. When the processor 210 executes the program, it implements the refrigerant reflux control method of the heat pump system described above.

[0068] According to the heat pump system of the present invention, the refrigerant backflow control method of the heat pump system described above can achieve double heating of the target area by controlling the on / off valve, thereby improving the heat exchange efficiency of the heat pump system, reducing the energy consumption of the system, and avoiding refrigerant backflow.

[0069] Corresponding to the above embodiments, the present invention also proposes a refrigerant reflux control device for a heat pump system.

[0070] Figure 5 This is a block diagram of a refrigerant reflux control device for a heat pump system according to an embodiment of the present invention.

[0071] like Figure 5 As shown in the figure, the refrigerant reflux control device of the heat pump system of the present invention includes a first refrigerant circuit, a second refrigerant circuit and an on / off valve. The device 100 may include a control module 110 and an acquisition module 120.

[0072] The control module 110, in response to a heating mode command, controls the on / off valve to heat the target area via the first refrigerant circuit. The acquisition module 120 acquires the high-pressure value of the first refrigerant circuit. The control module 110 also controls the on / off valve to connect the second refrigerant circuit in series with the first refrigerant circuit when the high-pressure value exceeds a first preset pressure threshold, so that the target area is heated through both the second and first refrigerant circuits.

[0073] According to one embodiment of the present invention, the on / off valve includes a first on / off valve, a second on / off valve, and a third on / off valve. A first refrigerant circuit includes a compressor, a first heat exchanger, a first throttling element, and a second heat exchanger. A second refrigerant circuit includes a second throttling element and a third heat exchanger. The discharge port of the compressor is connected to a first end of the first heat exchanger. The second end of the first heat exchanger is connected to one end of the first on / off valve and one end of the second on / off valve, respectively. The other end of the first on / off valve is connected to one end of the first throttling element and one end of the second throttling element, respectively. The other end of the first throttling element is connected to the first end of the second heat exchanger. The other end of the second throttling element is connected to the second refrigerant circuit via the third heat exchanger. The other end of the on / off valve is connected to one end of the third on / off valve, and the second end of the second heat exchanger and the other end of the third on / off valve are respectively connected to the suction port of the compressor. Specifically, the control module 110 controls the on / off valve to connect the second refrigerant circuit in series with the first refrigerant circuit, so as to heat the target area through the second and first refrigerant circuits. Specifically, it controls the second on / off valve to be in the open state and the first and third on / off valves to be in the closed state, so that the second refrigerant circuit is connected in series with the first refrigerant circuit; and controls the second throttling element, the first throttling element, and the compressor to be in the open state, so as to heat the target area through the second and first refrigerant circuits.

[0074] According to one embodiment of the present invention, the control module 110 controls the on-off valve to heat the target area through the first refrigerant circuit. Specifically, it controls the second on-off valve to be in a closed state, the first on-off valve to be in an open state, and the third on-off valve to be in an open or closed state, and controls the first throttling element and the compressor to be in an open state, so as to heat the target area through the first refrigerant circuit.

[0075] According to one embodiment of the present invention, the first refrigerant circuit further includes a third throttling element, the two ends of which are connected to the discharge port and suction port of the compressor respectively; wherein, during the cold start of the compressor, the control module 110 is further configured to control the opening degree of the third throttling element so that the suction superheat of the compressor is greater than a preset suction superheat, and when the suction superheat is greater than the preset suction superheat, control the first throttling element to be in the open state.

[0076] According to one embodiment of the present invention, the control module 110 is further configured to, in response to a cooling mode command, control the second on-off valve to be in a closed state, the first on-off valve and the third on-off valve to be in an open state, and control the second throttling element and the compressor to be in an open state, so as to cool the target area.

[0077] According to one embodiment of the present invention, the heat pump system further includes a battery heat exchange circuit for exchanging heat with the battery. The battery heat exchange circuit is connected to a first refrigerant circuit. When cooling a target area, the control module 110 is further configured to: acquire the cooling demand of the battery; and control the first refrigerant circuit based on the cooling demand of the battery so that the first refrigerant circuit cools the battery through the battery heat exchange circuit.

[0078] According to one embodiment of the present invention, the control module 110 controls the first refrigerant circuit based on the cooling demand of the battery, so that the first refrigerant circuit cools the battery through the battery heat exchange circuit. Specifically, it controls the opening degree of the first throttling element based on the cooling demand of the battery, so that the second heat exchanger exchanges heat with the battery heat exchange circuit, so as to cool the battery through the battery heat exchange circuit.

[0079] It should be noted that for details not disclosed in the refrigerant reflux control device of the heat pump system in this embodiment of the invention, please refer to the details disclosed in the refrigerant reflux control method of the heat pump system in this embodiment of the invention, which will not be repeated here.

[0080] According to an embodiment of the present invention, a refrigerant backflow control device for a heat pump system includes a control module that, in response to a heating mode command, controls an on / off valve to heat a target area via a first refrigerant circuit. An acquisition module acquires the high-pressure value of the first refrigerant circuit. Furthermore, when the high-pressure value exceeds a first preset pressure threshold, the control module controls the on / off valve to connect a second refrigerant circuit in series with the first refrigerant circuit, thereby heating the target area through both the second and first refrigerant circuits. Thus, this device can achieve two heating cycles for the target area by controlling the on / off valve, thereby improving the heat exchange efficiency of the heat pump system, reducing system energy consumption, and preventing refrigerant backflow.

[0081] Corresponding to the above embodiments, the present invention also proposes a vehicle.

[0082] Figure 6 This is a block diagram of a vehicle according to an embodiment of the present invention.

[0083] like Figure 6 As shown, the vehicle 300 of this embodiment may include the refrigerant return control device 100 of the heat pump system described above.

[0084] According to the vehicle of the present invention, the refrigerant backflow control device of the heat pump system described above can control the on / off valve to achieve double heating of the target area, thereby improving the heat exchange efficiency of the heat pump system, reducing the energy consumption of the system, and preventing refrigerant backflow.

[0085] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0086] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0087] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0088] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0089] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0090] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for controlling refrigerant reflux in a heat pump system, characterized in that, The heat pump system includes a first refrigerant circuit, a second refrigerant circuit, and an on / off valve; the method includes: In response to a heating mode command, the on / off valve is controlled to heat the target area via the first refrigerant circuit; Obtain the high pressure of the first refrigerant circuit; When the high pressure is greater than the first preset pressure threshold, the on / off valve is controlled to connect the second refrigerant circuit in series with the first refrigerant circuit, so as to heat the target area through the second refrigerant circuit and the first refrigerant circuit; The on / off valve includes a first on / off valve, a second on / off valve, and a third on / off valve. The first refrigerant circuit includes a compressor, a first heat exchanger, a first throttling element, and a second heat exchanger. The second refrigerant circuit includes a second throttling element and a third heat exchanger. The discharge port of the compressor is connected to a first end of the first heat exchanger. The second end of the first heat exchanger is connected to one end of the first on / off valve and one end of the second on / off valve, respectively. The other end of the first on / off valve is connected to one end of the first throttling element and one end of the second throttling element, respectively. The other end of the first throttling element is connected to the first end of the second heat exchanger. The other end of the second throttling element is connected to the other end of the second on / off valve and one end of the third on / off valve through the third heat exchanger, respectively. The second end of the second heat exchanger and the other end of the third on / off valve are connected to the suction port of the compressor, respectively.

2. The method according to claim 1, characterized in that, The control of the on / off valve to connect the second refrigerant circuit in series with the first refrigerant circuit, so as to heat the target area through the second refrigerant circuit and the first refrigerant circuit, includes: The second on / off valve is controlled to be in the open state, and the first on / off valve and the third on / off valve are in the closed state, so that the second refrigerant circuit is connected in series with the first refrigerant circuit; The second throttling element, the first throttling element, and the compressor are controlled to be in the on state so as to heat the target area through the second refrigerant circuit and the first refrigerant circuit.

3. The method according to claim 2, characterized in that, The control of the on / off valve to enable the first refrigerant circuit to heat the target area includes: The system controls the second on / off valve to be closed, the first on / off valve to be open, and the third on / off valve to be either open or closed. It also controls the first throttling element and the compressor to be on, so as to heat the target area through the first refrigerant circuit.

4. The method according to claim 3, characterized in that, The first refrigerant circuit further includes a third throttling element, the two ends of which are connected to the discharge port and suction port of the compressor respectively; wherein, during cold start of the compressor, the method further includes: The opening degree of the third throttling element is controlled so that the suction superheat of the compressor is greater than the preset suction superheat, and when the suction superheat is greater than the preset suction superheat, the first throttling element is controlled to be in the open state.

5. The method according to claim 2, characterized in that, The method further includes: In response to a cooling mode command, the second on / off valve is controlled to be closed, the first on / off valve and the third on / off valve are controlled to be open, and the second throttling element and the compressor are controlled to be turned on, so as to cool the target area.

6. The method according to claim 5, characterized in that, The heat pump system further includes a battery heat exchange circuit for heat exchange of the battery, the battery heat exchange circuit being connected to the first refrigerant circuit. When cooling the target area, the method further includes: Obtain the cooling requirements of the battery; The first refrigerant circuit is controlled based on the cooling requirements of the battery, so that the first refrigerant circuit cools the battery through the battery heat exchange circuit.

7. The method according to claim 6, characterized in that, The control of the first refrigerant circuit based on the cooling demand of the battery, so that the first refrigerant circuit cools the battery through the battery heat exchange circuit, includes: The opening degree of the first throttling element is controlled based on the cooling requirements of the battery, so that the second heat exchanger exchanges heat with the battery heat exchange circuit, thereby cooling the battery through the battery heat exchange circuit.

8. A heat pump system, characterized in that, include: A memory, a processor, and a program stored in the memory and executable on the processor, wherein when the processor executes the program, it implements the refrigerant reflux control method for a heat pump system according to any one of claims 1-7.

9. A refrigerant reflux control device for a heat pump system, characterized in that, The heat pump system includes a first refrigerant circuit, a second refrigerant circuit, and an on / off valve; the device includes: The control module is used to control the on / off valve in response to the heating mode command so that the first refrigerant circuit heats the target area; The acquisition module is used to acquire the high pressure of the first refrigerant circuit; The control module is also used to control the on / off valve to connect the second refrigerant circuit and the first refrigerant circuit in series when the high pressure is greater than the first preset pressure threshold, so as to heat the target area through the second refrigerant circuit and the first refrigerant circuit. The on / off valve includes a first on / off valve, a second on / off valve, and a third on / off valve. The first refrigerant circuit includes a compressor, a first heat exchanger, a first throttling element, and a second heat exchanger. The second refrigerant circuit includes a second throttling element and a third heat exchanger. The discharge port of the compressor is connected to a first end of the first heat exchanger. The second end of the first heat exchanger is connected to one end of the first on / off valve and one end of the second on / off valve, respectively. The other end of the first on / off valve is connected to one end of the first throttling element and one end of the second throttling element, respectively. The other end of the first throttling element is connected to the first end of the second heat exchanger. The other end of the second throttling element is connected to the other end of the second on / off valve and one end of the third on / off valve through the third heat exchanger, respectively. The second end of the second heat exchanger and the other end of the third on / off valve are connected to the suction port of the compressor, respectively.

10. A vehicle, characterized in that, Includes the refrigerant reflux control device for the heat pump system according to claim 9.

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