Vehicle heat pump air conditioning system

Abstract

A vehicle heat pump air conditioning system comprises: a compressor; a heat radiator; a first flow path provided with an outdoor heat exchanger and a first electronic expansion valve; a second flow path provided with a front evaporator and a second electronic expansion valve; a third flow path provided with a refrigerant-water heat exchanger and a third electronic expansion valve; a bypass pipeline provided with a first solenoid valve; a connecting pipeline provided with a second solenoid valve; and a liquid storage tank; any one of the first to third modes is operated by circulating a refrigerant mixed with lubricating oil; in the first mode, the first and third flow paths circulate the refrigerant in parallel; in the second mode, the first and second flow paths circulate the refrigerant in parallel; in the third mode, the refrigerant circulates in parallel with the second and third flow paths after flowing through the first flow path; and also comprises a controller; in the first to third modes, when oil accumulation occurs in a part of the multiple flow paths in which the refrigerant circulates in parallel, the controller performs oil return control to close the electronic expansion valves on other flow paths in the multiple flow paths in which the refrigerant circulates in parallel.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile air conditioning, and in particular to a heat pump air conditioning system for a vehicle. Background Art

[0002] At present, the demand for automotive thermal management is getting higher and higher. Single cooling, heating and dehumidification can no longer meet the needs of the whole vehicle. There is a need for battery cooling while cooling, or to increase indoor heating capacity and reduce power consumption, it is necessary to absorb energy from strong electricity or other waste heat sources. In order to cope with this situation, it is necessary to install two or more heat exchangers in the circuit of the automotive heat pump air conditioning system.

[0003] Since connecting heat exchangers in series will increase pressure loss and affect performance, many manufacturers choose to set up two heat exchangers in parallel. When the compressor in the loop is working, the lubricating oil used to lubricate the compressor is mixed with the refrigerant and circulates throughout the loop. However, when the heat exchangers are set in parallel, the flow will be diverted. The reduction in flow will cause the lubricating oil to easily accumulate in the heat exchanger and the pipeline behind it, which will cause the compressor to be starved of oil due to lack of lubricating oil, which may cause the compressor to get stuck or damaged.

[0004] In the prior art, the throttling device of the circuit is usually opened to increase the flow of the circuit, so that the lubricating oil in the pipeline returns to the compressor. However, the current automotive heat pump air conditioning system can usually work in multiple modes, and this measure cannot effectively prevent the compressor from being poor in oil in all modes of the automotive heat pump air conditioning system. Summary of the invention

[0005] Problems to be solved by the invention:

[0006] In view of the above problems, the object of the present invention is to provide a vehicle heat pump air-conditioning system that can ensure the circulation rate and circulation volume of the lubricating oil of the compressor, and can dynamically control the opening and closing of each flow path according to the oil storage status in the system under various operating modes, so that the lubricating oil accumulated in the flow path can return to the compressor.

[0007] Technical means to solve the problem:

[0008] To solve the above problems, a vehicle heat pump air-conditioning system as one aspect of the present invention includes: a compressor; a radiator; a first flow path provided with an outdoor heat exchanger and a first electronic expansion valve closer to the upstream side thereof; a second flow path provided with a front evaporator and a second electronic expansion valve closer to the upstream side thereof; a third flow path provided with a refrigerant-water heat exchanger and a third electronic expansion valve closer to the upstream side thereof; a bypass pipeline provided with a first solenoid valve; a connecting pipeline provided with a second solenoid valve; and a liquid storage tank; in the vehicle heat pump air-conditioning system, any one of the first to third modes is operated by circulating a refrigerant mixed with lubricating oil for lubricating the compressor under the action of the compressor; in the first mode, the first solenoid valve and the second solenoid valve are opened, the second electronic expansion valve is in a closed state, and the first flow path and the third flow path circulate the refrigerant in parallel. refrigerant; in the second mode, the first solenoid valve and the second solenoid valve are opened, the third electronic expansion valve is in a closed state, and the first flow path and the second flow path circulate the refrigerant in parallel; in the third mode, the first solenoid valve and the second solenoid valve are closed, and after the refrigerant flows through the first flow path, the second flow path and the third flow path circulate the refrigerant in parallel; it also includes a controller for controlling at least any one of the first electronic expansion valve, the second electronic expansion valve and the third electronic expansion valve; in the first to third modes, when oil accumulation occurs in part of the multiple flow paths through which the refrigerant circulates in parallel, the controller performs oil return control to increase the flow rate of the refrigerant on the flow path where oil accumulation occurs by closing the electronic expansion valves on other flow paths among the multiple flow paths through which the refrigerant circulates in parallel.

[0009] According to the present invention, an electronic expansion valve is arranged before each evaporator and heat exchanger, and a controller is used to perform oil return control when oil accumulation occurs in a certain flow path, so that the accumulated lubricating oil returns to the compressor. Therefore, the intake oil circulation rate and oil circulation amount of the compressor can be guaranteed, and the quality of the compressor can be guaranteed.

[0010] Effect of the invention:

[0011] The present invention can ensure the circulation rate and circulation volume of the lubricating oil of the compressor, and prevent the compressor from being depleted of oil or being damaged by the inflow of liquid refrigerant during operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a schematic structural diagram of a vehicle heat pump air conditioning system according to an embodiment of the present invention;

[0013] Figure 2 It is a control flow chart of a controller in a vehicle heat pump air conditioning system;

[0014] Figure 3 yes Figure 1 A schematic structural diagram of a modified example of a vehicle heat pump air conditioning system is shown;

[0015] Figure 4 is a schematic structural diagram of a vehicle heat pump air conditioning system according to another embodiment of the present invention;

[0016] Figure 5 yes Figure 4 A schematic structural diagram of a modified example of a vehicle heat pump air conditioning system is shown;

[0017] Explanation of symbols:

[0018] 100, 100A, heat pump air-conditioning system with liquid storage tank (liquid storage tank heat pump system); 200, 200A, heat pump air-conditioning system with gas-liquid separator (gas-liquid separator heat pump system); 1, compressor; 2, heat radiator; 3a, first solenoid valve; 3b, second solenoid valve; 3c, third solenoid valve; 4, liquid storage tank; 5, gas-liquid separator; 11, outdoor heat exchanger (outdoor unit); 12, first electronic expansion valve; 13, CS integrated valve; 21, front evaporator; 22, second electronic expansion valve; 31, refrigerant-water heat exchanger; 32, third electronic expansion valve; 41, rear evaporator; 42, fourth electronic expansion valve; 60, check valve; 61, first check valve; 62, second check valve; 63, third check valve. DETAILED DESCRIPTION

[0019] The present invention is further described below in conjunction with the accompanying drawings and the following embodiments. It should be understood that the accompanying drawings and the following embodiments are only used to illustrate the present invention rather than to limit the present invention.

[0020] Disclosed herein is a vehicle heat pump air conditioning system that can dynamically control the opening and closing of each flow path according to the oil storage status in the system under multiple operating modes to ensure that the lubricating oil stored in the circuit returns to the compressor.

[0021] The automotive heat pump air conditioning system is suitable for automotive air conditioning devices installed in vehicles. It controls the state of the refrigerant flowing in the circuit to exchange heat with the air to cool or heat the air supplied to the vehicle interior. In addition, the automotive heat pump air conditioning system realizes functions such as dehumidification in the vehicle, battery cooling, and waste heat recovery by circulating the refrigerant in different flow paths.

[0022] Figure 1 is a schematic diagram of a vehicle heat pump air conditioning system according to an embodiment of the present invention, specifically, Figure 1 A heat pump air conditioning system with a liquid storage tank (hereinafter referred to as a "liquid storage tank heat pump system") 100 is shown. Figure 1As shown, a compressor 1 is provided in the vehicle heat pump air conditioning system, and the compressor 1 may be an electric compressor. Refrigerant circulates in the vehicle heat pump air conditioning system. The compressor 1 inhales low-temperature and low-pressure gas refrigerant from the suction port, compresses the piston through the operation of the motor, and then discharges high-temperature and high-pressure gas refrigerant from the discharge port. The refrigerant is mixed with lubricating oil for lubricating the compressor 1, and the two circulate together in the vehicle heat pump air conditioning system under the action of the compressor 1.

[0023] A radiator 2 is connected to the outlet of the compressor 1, that is, the downstream side of the compressor 1. The radiator 2 may be an indoor condenser placed in the housing of the air conditioning unit, or a water-cooled condenser placed in the vehicle cabin, and the water-cooled condenser and the warm air core in the air conditioning unit are connected by a water path (omitted in the figure). The radiator 2 heats the vehicle cabin by exchanging heat between the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 and the air in the vehicle cabin, or heats the refrigerant and water, and then the water passes through the warm air core, including heat exchange with the indoor air, to release heat, thereby heating the vehicle cabin.

[0024] In the vehicle heat pump air conditioning system, the first to third flow paths, the bypass pipeline and the connecting pipeline are respectively connected to the downstream side of the heat radiator 2. Figure 1 As shown, a plurality of nodes are formed in the circuit, and these nodes can be diversion points or confluence points according to the refrigerant circulation conditions, and multi-way valves can be provided at these nodes to divert the flow path. The first flow path extends from node A to node B on the downstream side of the heat radiator 2, and a first electronic expansion valve 12 and an outdoor heat exchanger 11 are sequentially arranged along the refrigerant flow direction on the first flow path. The connecting pipeline extends from node B to node C on the downstream side of the outdoor heat exchanger 11 described later, and a second solenoid valve 3b is arranged on the connecting pipeline. A liquid storage tank 4, the above-mentioned compressor 1 and the heat radiator 2 are sequentially arranged between node C and node A. On the other hand, a bypass pipeline is branched from node A to node D on the downstream side of the heat radiator 2, and a first solenoid valve 3a is arranged on the bypass pipeline. On the downstream side of node D, the second flow path and the third flow path extend in parallel from node D' to node C' located on the upstream side of node C, respectively. On the second flow path, a second electronic expansion valve 22 and a front evaporator 21 are sequentially arranged along the refrigerant flow direction, and on the third flow path, a third electronic expansion valve 32 and a refrigerant-water heat exchanger 31 are sequentially arranged along the refrigerant flow direction. In this embodiment, the flow condition of the refrigerant in the vehicle heat pump air conditioning system can be controlled by selectively connecting or blocking these flow paths, thereby realizing different working modes to meet the thermal management requirements of the vehicle.

[0025] On the first flow path extending from node A to node B, the first electronic expansion valve 12 is an electrically variable throttling mechanism that can change its opening according to a control signal output by a controller described later. The first electronic expansion valve 12 no longer plays a role of reducing pressure and throttling when fully open, and only serves as a refrigerant passage to circulate refrigerant. When fully closed, the first flow path is blocked to prevent refrigerant from passing through.

[0026] The outdoor heat exchanger (sometimes simply referred to as “outdoor device”) 11 is in contact with outside air such as wind generated when a vehicle is traveling, and exchanges heat between the refrigerant flowing out of the first electronic expansion valve 12 and the outside air.

[0027] like Figure 1 As shown, in this embodiment, the inlet of the first electronic expansion valve 12 is connected to the outlet side of the radiator 2, the outlet of the outdoor heat exchanger 11 is connected to the inlet of the liquid storage tank 4 through a connecting pipeline provided with a second electromagnetic valve 3b, and the outlet of the liquid storage tank 4 is connected to the suction port of the compressor 1 through a pipeline. The second electromagnetic valve 3b is an on-off valve that can open and close the pipeline between the outdoor heat exchanger 11 and the liquid storage tank 4 under the control of a controller described later. The liquid storage tank 4 is provided with an oil return port (not shown), which returns the lubricating oil to the compressor 1 by sucking a small portion of the oil-liquid refrigerant mixture into the compressor 1.

[0028] In addition, a CS integrated valve 13 may be provided between the outdoor heat exchanger 11 and the first electronic expansion valve 12 on the first flow path. The CS integrated valve 13 is connected to the compressor 1 through a pipeline. When a large capacity heating is required (for example, the first mode described later), the refrigerant flowing out of the first electronic expansion valve 12 is separated into gas and liquid in the CS integrated valve 13, and the gas portion thereof returns to the compressor 1 through the pipeline, and the liquid portion undergoes a second throttling and becomes a gas-liquid mixture and flows into the outdoor heat exchanger 11. In other cases (for example, the second mode and the third mode described later), the CS integrated valve 13 closes the pipeline connected to the compressor 1, does not undergo a second throttling, does not change the fluid state, and only serves as a refrigerant passage for the refrigerant to pass through.

[0029] In the second flow path extending from node D' to node C', the second electronic expansion valve 22 has the same structure as the first electronic expansion valve 12. It is an electric variable throttling mechanism that can adjust the opening according to the control signal output by the controller. When it is fully open, it only serves as a refrigerant passage for the refrigerant to pass through, and when it is fully closed, it blocks the second flow path.

[0030] The front evaporator 21 is arranged in the shell of the indoor air-conditioning unit, so that the low-temperature and low-pressure refrigerant discharged from the second electronic expansion valve 22 exchanges heat with the supply air to the vehicle interior, more specifically, to the front part of the vehicle interior, namely the driver's seat and the front passenger seat, thereby absorbing heat and cooling it, thereby dehumidifying or cooling the vehicle interior.

[0031] On the third flow path extending from node D' to node C' in parallel with the above-mentioned second flow path, the third electronic expansion valve 32 has the same structure as the first electronic expansion valve 12 and the second electronic expansion valve 22. It is an electric variable throttling mechanism that can adjust the opening according to the control signal output by the controller. When it is fully open, it only serves as a refrigerant passage for the refrigerant to pass through, and when it is fully closed, it blocks the third flow path.

[0032] In addition to the vehicle heat pump air conditioning system, the automotive thermal management system is also provided with a cooling water circuit (not shown), in which cooling water circulates, and is cooled by heat exchange with the corresponding waste heat generating components in a heat exchanger provided on the battery (and other strong electrical components). In this embodiment, these high-temperature cooling waters flow in from the cooling water inlet of the refrigerant-water heat exchanger 31, and heat exchange with the low-temperature refrigerant flowing in from the refrigerant inlet in the refrigerant-water heat exchanger 31 to become low-temperature cooling water, and are discharged from the cooling water outlet, and then flow into the heat exchanger of the cooling water circuit again to cool the battery and other strong electrical components. Thus, the refrigerant-water heat exchanger 31 can function as a battery cooler or a waste heat recovery device.

[0033] like Figure 1 As shown, in this embodiment, the second flow path and the third flow path are connected in parallel to both sides of the second solenoid valve 3b. More specifically, the outlet of the outdoor heat exchanger 11 is not only connected to the liquid storage tank 4 through the second solenoid valve 3b, but also connected to the inlet of the second electronic expansion valve 22 of the second flow path and the inlet of the third electronic expansion valve 32 of the third flow path through another pipeline extending from node B to node D, and a check valve 60 is also provided on the pipeline. The check valve 60 allows the refrigerant to flow from the outlet of the outdoor heat exchanger 11 to the inlet of the second electronic expansion valve 22 and the third electronic expansion valve 32, while prohibiting its reverse flow. On the other hand, the outlet side of the front evaporator 21 and the refrigerant-water heat exchanger 31 are connected to the liquid storage tank 4, so that the refrigerant after heat exchange returns to the compressor 1 through the liquid storage tank 4.

[0034] As described above, a bypass pipeline is also provided in the liquid storage tank heat pump system 100, one end of which is located between the radiator 2 and the first electronic expansion valve 12, and the other end is located between the check valve 60, the second electronic expansion valve 22 and the third electronic expansion valve 32 on the pipeline connecting the outlet of the outdoor heat exchanger 11 and the inlet of the second electronic expansion valve 22 and the third electronic expansion valve 32, that is, located closer to the downstream side than the check valve 60. A first solenoid valve 3a is provided on the bypass pipeline, and the first solenoid valve 3a has the same structure as the second solenoid valve 3b, and is an on-off valve that can open and close the bypass pipeline under the control of the controller described later. In other words, the bypass pipeline is formed into a structure that can divert a part of the refrigerant flowing out of the radiator 2 to the second flow path and / or the third flow path when the first solenoid valve 3a is opened.

[0035] In addition, the liquid storage tank heat pump system 100 also includes a controller (not shown). The controller may be, for example, a microcomputer having a memory such as a ROM and a RAM and a CPU, and the CPU executes a program stored in the ROM. The controller issues control instructions to each electronic expansion valve, each solenoid valve, etc. in the liquid storage tank heat pump system 100 to control the opening and closing conditions of each valve to realize different thermal management modes, and adjusts the opening size of each valve to meet the workload under these thermal management modes.

[0036] In the liquid storage tank heat pump system 100 with the above structure, the controller controls at least one of the electronic expansion valves and the solenoid valves to change the circuit structure, so that the refrigerant mixed with the lubricating oil for lubricating the compressor 1 circulates in the liquid storage tank heat pump system 100 with different circuit structures under the action of the compressor 1 to operate any one of the first to third modes. Figure 1 The first to third modes of the tank heat pump system 100 are described.

[0037] [First Mode]

[0038] The first mode of the liquid storage tank heat pump system 100 is the vehicle interior heating and waste heat recovery mode. In this mode, the vehicle heat pump air conditioning system heats the vehicle interior through the heat emitter 2 and recovers the waste heat generated by the battery and / or other high-voltage components through the refrigerant-water heat exchanger 31.

[0039] Specifically, in the first mode, the controller opens the first solenoid valve 3a to connect the bypass line, opens the second solenoid valve 3b to connect the connecting line, and closes the second electronic expansion valve 22 to block the second flow path. At this time, the refrigerant mixed with lubricating oil circulates in the liquid storage tank heat pump system 100 in the following manner.

[0040] The low-temperature, low-pressure gas refrigerant is compressed by the compressor 1 and becomes a high-temperature, high-pressure gas, which is discharged from the discharge port and flows into the radiator 2. The high-temperature, high-pressure gas refrigerant exchanges heat with the supply air that is supplied to the vehicle interior in the radiator 2, thereby heating the vehicle interior by heating the supply air. The refrigerant that becomes a high-pressure liquid after heat release is divided into two paths and flows into the first flow path and the bypass pipe respectively.

[0041] The refrigerant flowing into the first flow path becomes a medium-pressure gas-liquid two-phase body after passing through the first electronic expansion valve 12, and then flows into the CS integrated valve 13 for gas-liquid separation. The gas part of the refrigerant directly returns to the compressor 1 through the pipeline connecting the CS integrated valve 13 and the compressor 1, and the liquid part of the refrigerant becomes a low-pressure gas-liquid two-phase body after the second throttling in the CS integrated valve 13 and flows into the outdoor heat exchanger 11. After passing through the outdoor heat exchanger 11, the refrigerant becomes a low-pressure nearly saturated gas two-phase refrigerant and flows into the liquid storage tank 4 through the second solenoid valve 3b.

[0042] On the other hand, since the second electronic expansion valve 22 is closed, the refrigerant flowing into the bypass pipeline flows to the third flow path through the first solenoid valve 3a. The high-pressure liquid refrigerant discharged from the radiator 2 passes through the third electronic expansion valve 32 in the third flow path to become a low-pressure two-phase refrigerant, and absorbs waste heat after heat exchange with cooling water in the refrigerant-water heat exchanger 31 to become a low-pressure gaseous refrigerant. The low-pressure gaseous refrigerant merges with the other refrigerant passing through the second solenoid valve 3b and returns to the compressor 1 through the liquid storage tank 4.

[0043] According to the above structure, under the control of the controller, the first flow path and the third flow path of the receiver heat pump system 100 flow refrigerant in parallel, thereby heating the vehicle and recovering waste heat at the same time.

[0044] [Second Mode]

[0045] The second mode of the tank heat pump system 100 is a vehicle interior heating and dehumidification mode, in which the vehicle heat pump air conditioning system heats the vehicle interior through the radiator 2 and dehumidifies the vehicle interior through the front evaporator 21 .

[0046] Specifically, in the second mode, the controller opens the first solenoid valve 3a to connect the bypass line, opens the second solenoid valve 3b to connect the connecting line, and closes the third electronic expansion valve 32 to block the second flow path. At this time, the refrigerant mixed with lubricating oil circulates in the liquid storage tank heat pump system 100 in the following manner.

[0047] Similar to the first mode mentioned above, the low-temperature and low-pressure gas refrigerant is compressed by the compressor 1 to become a high-temperature and high-pressure gas and flows into the radiator 2. The high-temperature and high-pressure gas refrigerant exchanges heat with the supply air in the radiator 2 to heat the vehicle interior. The refrigerant that becomes a high-pressure liquid after heat release is divided into two paths and flows into the first flow path and the bypass pipe respectively.

[0048] The refrigerant flowing into the first flow path is also the same as the first mode described above. After passing through the first electronic expansion valve 12, it becomes a low-pressure gas-liquid two-phase body, and flows into the outdoor heat exchanger 11 after passing through the CS integration valve. In the second mode, the CS integration valve closes the pipeline connected to the compressor 1 as described above, and does not separate the gas and liquid of the refrigerant passing through, but only acts as a passage. After passing through the outdoor heat exchanger 11, the refrigerant becomes a low-pressure nearly saturated gas two-phase refrigerant, and flows into the liquid storage tank 4 through the second solenoid valve 3b.

[0049] On the other hand, since the third electronic expansion valve 32 is closed, the refrigerant flowing into the bypass pipeline flows to the second flow path through the first electromagnetic valve 3a. The high-pressure liquid refrigerant discharged from the radiator 2 passes through the second electronic expansion valve 22 in the second flow path to become a low-pressure two-phase refrigerant, and heat exchanges with the indoor air in the front evaporator to dehumidify it, thereby becoming a low-pressure gaseous refrigerant. The low-pressure gaseous refrigerant merges with the other refrigerant passing through the second electromagnetic valve 3b and returns to the compressor 1 through the liquid storage tank 4.

[0050] According to the above configuration, under the control of the controller, the first flow path and the second flow path of the receiver heat pump system 100 flow refrigerant in parallel, thereby dehumidifying the air in the vehicle interior while heating the vehicle interior.

[0051] [Third Mode]

[0052] The third mode of the tank heat pump system 100 is a vehicle interior cooling and battery cooling mode. In this mode, the vehicle heat pump air conditioning system cools the vehicle interior through the front evaporator 21 and cools the battery through the refrigerant-water heat exchanger 31.

[0053] Specifically, in the third mode, the controller closes the first solenoid valve 3a to block the bypass line, closes the second solenoid valve 3b to block the connecting line, and can prevent the refrigerant from directly flowing into the liquid storage tank 4 after passing through the outdoor heat exchanger 11. At this time, the refrigerant mixed with lubricating oil circulates in the liquid storage tank heat pump system 100 in the following form.

[0054] In the third mode, the radiator 2 only functions as a refrigerant passage. The low-temperature, low-pressure gas refrigerant is compressed by the compressor 1 to become a high-temperature, high-pressure gas, and releases heat in the outdoor heat exchanger 11 to become a high-pressure liquid refrigerant. After passing through the radiator 2 as the refrigerant passage, it becomes a low-pressure gas-liquid two-phase body at the first electronic expansion valve 12, and flows through the outdoor heat exchanger 11 as the refrigerant passage after passing through the CS integration valve. In this third mode, the CS integration valve closes the pipeline connected to the compressor 1 as described above, and does not separate the refrigerant passing through the gas and liquid, but only functions as a passage. Since the second solenoid valve 3b is closed, the refrigerant flowing out of the outdoor heat exchanger 11 passes through the check valve 60 and flows into the second flow path and the third flow path respectively in two ways.

[0055] The refrigerant flowing into the second flow path passes through the second electronic expansion valve 22 and becomes a low-pressure two-phase refrigerant. In the front evaporator, it exchanges heat with the supply air that is supplied to the vehicle interior, thereby cooling the vehicle interior by cooling the supply air, thereby becoming a low-pressure nearly saturated vapor two-phase refrigerant. On the other hand, the refrigerant flowing into the third flow path passes through the third electronic expansion valve 32 and becomes a low-pressure gaseous refrigerant after the cooling water is cooled by the refrigerant-water heat exchanger 31. The low-temperature cooling water circulates in the cooling water circuit to cool the battery. The refrigerant flowing out of the second flow path merges with the refrigerant flowing out of the third flow path and returns to the compressor 1 through the liquid storage tank 4.

[0056] According to the above structure, under the control of the controller, after the refrigerant in the liquid storage tank heat pump system 100 flows through the first flow path which only serves as a refrigerant passage, the second flow path and the third flow path circulate the refrigerant in parallel, thereby cooling the battery while cooling the vehicle interior.

[0057] (Oil return control)

[0058] In the above-mentioned first to third modes, the refrigerant always flows in two of the first to third flow paths in parallel, so the flow of the refrigerant will be diverted. The reduction in flow will cause the lubricating oil flowing with the refrigerant to easily accumulate in each heat exchanger and the subsequent pipelines.

[0059] In this embodiment, in order to prevent the compressor from running out of oil due to lack of lubricating oil, the controller in the automotive heat pump air conditioning system repeatedly performs oil return control to increase the refrigerant flow in the flow path where oil accumulation occurs when it is determined that oil accumulation occurs in each flow path, so that the accumulated oil returns to the compressor. Figure 2 It is a control flow chart of a controller in a vehicle heat pump air conditioning system.

[0060] like Figure 2 As shown, the controller first determines whether oil accumulation occurs in each flow path. In more detail, the controller calculates the total flow rate based on the compressor capacity, the density of the refrigerant at the compressor inlet, the number of revolutions of the compressor, etc., and then detects and calculates the flow rate of each branch flow path based on the actuation instructions (action pls) and the actuation area of ​​each valve. The memory stores the oil accumulation flow thresholds pre-set for each branch flow path according to the diameter and layout of the low-pressure piping. After calculating the flow rates of each branch flow path, the controller compares them with the corresponding oil accumulation flow thresholds to determine whether oil accumulation occurs in each branch flow path.

[0061] When oil accumulation occurs in a part of the multiple flow paths through which the refrigerant circulates in parallel, the controller performs oil return control to close the electronic expansion valves on the other flow paths through which the refrigerant circulates in parallel to increase the refrigerant flow rate on the flow path through which the oil accumulation occurs, so that the accumulated lubricating oil returns to the oil return control of the compressor 1. When the electronic expansion valves of other flow paths are closed under the control of the controller, the refrigerant flow rate is concentrated to the flow path through which the oil accumulation occurs, so that the accumulated lubricating oil is driven back to the compressor. Therefore, the above-mentioned oil return control can also be called flow concentration control.

[0062] In this embodiment, the controller cancels the oil return control after executing the oil return control for a predetermined time. The so-called canceling of the oil return control means restoring the opening of the electronic expansion valve on each branch flow path to the opening before executing the oil return control. The predetermined time can be set according to the actual situation of the automobile thermal management system, for example, it can be 30 seconds.

[0063] The control method of the controller is described in detail below in conjunction with the first to third modes of the liquid storage tank heat pump system 100.

[0064] In the first mode, the controller blocks the second flow path by closing the second electronic expansion valve 22. After leaving the heat emitter 2, the refrigerant flows in parallel in the first flow path provided with the first electronic expansion valve 12 and the outdoor heat exchanger 11 and in the third flow path provided with the third electronic expansion valve 32 and the refrigerant-water heat exchanger 31, thereby heating the vehicle and recovering waste heat at the same time.

[0065] The controller detects and calculates the refrigerant flow rates in the first flow path and the third flow path, and compares them with the oil accumulation flow thresholds set for the first flow path and the third flow path, respectively. When the calculated refrigerant flow rate of the first flow path is less than the oil accumulation flow threshold of the first flow path, the controller determines that oil accumulation occurs on the first flow path, and performs oil return control on the first flow path. Specifically, the controller issues a control instruction to the third electronic expansion valve 32 on the third flow path to control it to close, so that the refrigerant originally circulating in the third flow path is concentrated in the first flow path, in other words, all the refrigerant in the circuit flows from the radiator 2 into the first flow path. The refrigerant flow rate in the first flow path increases, and the accumulated lubricating oil is flushed back to the compressor 1.

[0066] On the other hand, when the calculated refrigerant flow rate of the third flow path is less than the oil accumulation flow rate threshold of the third flow path, the controller determines that oil accumulation occurs on the third flow path and performs oil return control on the third flow path. Specifically, the controller issues a control instruction to the first electronic expansion valve 12 on the first flow path to control it to close, so that the refrigerant originally flowing in the first flow path is concentrated in the third flow path. In other words, all the refrigerant flowing out of the radiator 2 flows into the third flow path via the bypass pipeline. The refrigerant flow rate in the third flow path increases, and the accumulated lubricating oil is flushed back to the compressor 1.

[0067] As described above, in the first mode, when it is determined that oil accumulation occurs in any one of the first flow path and the third flow path in parallel, the controller closes the electronic expansion valve on the other flow path to increase the refrigerant flow on the flow path where oil accumulation occurs, thereby driving the lubricating oil accumulated in the first flow path back to the compressor 1. However, when the third electronic expansion valve 32 is shut down, the refrigerant flow in the first flow path will suddenly increase, and the first electronic expansion valve 12 will present a valve opening too small relative to the refrigerant flow in the first flow path, which may cause a sharp rise in the high-pressure side pressure, increase the system fluctuation, and the high pressure may cause damage to the compressor or other components. Therefore, in this embodiment, the controller appropriately increases the opening of the electronic expansion valve on the flow path where oil accumulation occurs while closing the electronic expansion valve on the flow path where oil accumulation does not occur, thereby preventing the high pressure from rising. The increase in the opening of the electronic expansion valve on the flow path where oil accumulation occurs is ideally equal to the opening closing amount of the electronic expansion valve on the remaining flow paths, thereby reducing the fluctuation of the system.

[0068] Therefore, the controller performs control in the following manner in the first mode.

[0069] When it is determined that oil accumulation occurs in the first flow path, the controller closes the third electronic expansion valve 32 on the third flow path, and at the same time increases the opening of the first electronic expansion valve 12 in a form in which the increase in the opening of the first electronic expansion valve 12 is equal to the closing amount of the opening of the third electronic expansion valve 32, thereby performing oil return control to return the lubricating oil accumulated in the first flow path to the compressor 1. After the oil return control continues for a specified time (for example, 30 seconds), the controller opens the third electronic expansion valve 32 closed due to the oil return control to the original opening, and at the same time reduces the opening of the first electronic expansion valve 12 in the first flow path as the oil accumulation flow path to the original state.

[0070] When it is determined that oil accumulation occurs in the third circuit, the controller closes the first electronic expansion valve 12 on the first flow path, and at the same time increases the opening of the third electronic expansion valve 32 in a form in which the increase in the opening of the third electronic expansion valve 32 is equal to the closing amount of the opening of the first electronic expansion valve 12, thereby performing oil return control to return the lubricating oil accumulated in the third flow path to the compressor 1. After the oil return control continues for a specified time (for example, 30 seconds), the controller opens the first electronic expansion valve 12 closed due to the oil return control to the original opening, and at the same time reduces the opening of the third electronic expansion valve 32 in the third flow path as the oil accumulation flow path to the original state.

[0071] According to the above control, the receiver heat pump system 100 can perform oil return control for returning the lubricating oil accumulated in the flow path to the compressor 1 by adjusting the opening of the electronic expansion valve in each flow path in the first mode.

[0072] In the second mode, the controller blocks the third flow path by closing the third electronic expansion valve 32. After leaving the heat emitter 2, the refrigerant flows in parallel in the first flow path provided with the first electronic expansion valve 12 and the outdoor heat exchanger 11 and the second flow path provided with the second electronic expansion valve 22 and the front evaporator 21, thereby dehumidifying the air in the vehicle interior while heating the vehicle.

[0073] Similar to the first mode, in the second mode, when the liquid storage tank heat pump system 100 determines that oil accumulation occurs in the first flow path, the controller closes the second electronic expansion valve 22 on the second flow path, and increases the opening of the first electronic expansion valve 12 in a form in which the opening increase amount of the first electronic expansion valve 12 is equal to the opening closing amount of the second electronic expansion valve 22, thereby performing oil return control to return the lubricating oil accumulated in the first flow path to the compressor 1. When it is determined that oil accumulation occurs in the second flow path, the controller closes the first electronic expansion valve 12 on the first flow path, and increases the opening of the second electronic expansion valve 22 in a form in which the opening increase amount of the second electronic expansion valve 22 is equal to the opening closing amount of the first electronic expansion valve 12, thereby performing oil return control to return the lubricating oil accumulated in the second flow path to the compressor 1. After the oil return control continues for a predetermined time (for example, 30 seconds), the controller opens the electronic expansion valve on the flow path without oil accumulation that is closed due to the oil return control to the original opening, and reduces the opening of the electronic expansion valve in the oil accumulation flow path to the original state. Therefore, the receiver heat pump system 100 can perform oil return control for returning the lubricating oil accumulated in the flow path to the compressor 1 by adjusting the opening of the electronic expansion valve in each flow path in the second mode.

[0074] In the third mode, the controller closes the first solenoid valve 3a and the second solenoid valve 3b. The refrigerant sent from the compressor 1 flows through the first flow path provided with the first electronic expansion valve 12, and then flows in parallel in the third flow path provided with the second electronic expansion valve 22 and the front evaporator 21 and the third electronic expansion valve 32 and the refrigerant-water heat exchanger 31, thereby cooling the battery while cooling the vehicle interior.

[0075] Similar to the first mode, in the third mode, when the liquid storage tank heat pump system 100 determines that oil accumulation occurs in the second flow path, the controller closes the third electronic expansion valve 32 on the third flow path, and at the same time increases the opening of the second electronic expansion valve 22 in a form in which the opening increase amount of the second electronic expansion valve 22 is equal to the opening closing amount of the third electronic expansion valve 32, thereby performing oil return control to return the lubricating oil accumulated in the second flow path to the compressor 1. When it is determined that oil accumulation occurs in the third flow path, the controller closes the second electronic expansion valve 22 on the second flow path, and at the same time increases the opening of the third electronic expansion valve 32 in a form in which the opening increase amount of the third electronic expansion valve 32 is equal to the opening closing amount of the second electronic expansion valve 22, thereby performing oil return control to return the lubricating oil accumulated in the third flow path to the compressor 1. After the oil return control continues for a predetermined time (for example, 30 seconds), the controller opens the electronic expansion valve on the flow path without oil accumulation that is closed due to the oil return control to the original opening, and at the same time reduces the opening of the electronic expansion valve in the oil accumulation flow path to the original state. Therefore, in the third mode, the receiver heat pump system 100 can perform oil return control for returning the lubricating oil accumulated in the flow path to the compressor 1 by adjusting the opening of the electronic expansion valve in each flow path.

[0076] Figure 3 1 is a schematic diagram of a liquid storage tank heat pump system 100A as a modified example of the liquid storage tank heat pump system 100. The liquid storage tank heat pump system 100A has the same structure as the liquid storage tank heat pump system 100 except that a fourth flow path is further provided. Figure 3 The structure of the tank heat pump system 100A will be described mainly with respect to the fourth flow path.

[0077] Specifically, if Figure 3 As shown, a node E and a node E' are also formed in the circuit. The fourth flow path extends from node E to node E' and is connected in parallel to both sides of the second solenoid valve 3b like the second flow path and the third flow path. A fourth electronic expansion valve 42 and a rear evaporator 41 are sequentially arranged on the fourth flow path along the refrigerant flow direction.

[0078] The fourth electronic expansion valve 42 has the same structure as the first electronic expansion valve 12, and is an electrically variable throttling mechanism that can adjust the opening according to the control signal output by the controller. When fully open, it only serves as a refrigerant passage for the refrigerant to pass through, and when fully closed, it blocks the fourth flow path. Therefore, as long as the controller controls the fourth electronic expansion valve 42 to close to block the fourth flow path, the liquid storage tank heat pump system 100A can also execute the above-mentioned first to third modes.

[0079] The rear evaporator 41 is also arranged in the shell of the indoor air-conditioning unit, so that the low-temperature and low-pressure refrigerant discharged from the fourth electronic expansion valve 42 exchanges heat with the supply air to the vehicle interior, more specifically, to the rear part of the vehicle interior, i.e., the rear seats, thereby absorbing heat and cooling it, thereby cooling the rear part of the vehicle interior.

[0080] [Fourth Mode]

[0081] By providing the fourth flow path, the receiver heat pump system 100A can execute a fourth mode for cooling the front and rear of the vehicle interior simultaneously in addition to the first to third modes.

[0082] The flow mode of the refrigerant in the vehicle heat pump air conditioning system in the fourth mode is similar to that in the third mode. The controller closes the first solenoid valve 3a and the second solenoid valve 3b, and the radiator 2 only functions as a refrigerant passage. The controller also closes the third electronic expansion valve 32 on the third flow path to block the third flow path.

[0083] The low-temperature, low-pressure gas refrigerant is compressed by the compressor 1 to become a high-temperature, high-pressure gas. After passing through the first electronic expansion valve 12, it passes through the CS integrated valve and flows through the outdoor heat exchanger 11 as a refrigerant passage, where it releases heat and becomes a high-pressure liquid. In the fourth mode, the CS integrated valve closes the pipeline connected to the compressor 1 as described above, and does not separate the refrigerant passing through it into gas and liquid, but only acts as a passage. Since the second solenoid valve 3b and the third electronic expansion valve 32 are closed, the refrigerant flowing out of the outdoor heat exchanger 11 flows into the second flow path and the fourth flow path respectively after passing through the check valve 60.

[0084] The refrigerant flowing into the second flow path and the fourth flow path is converted into a low-pressure two-phase refrigerant through the electronic expansion valves on each flow path, and is heat-exchanged with the supply air for supplying air to the vehicle interior in the front evaporator 21 and the rear evaporator 41, respectively, so as to cool the vehicle interior by cooling the supply air, thereby converting into a low-pressure gaseous refrigerant. The refrigerants flowing out of the second flow path and the fourth flow path are combined and returned to the compressor 1 through the liquid storage tank 4.

[0085] According to the above structure, under the control of the controller, after the refrigerant in the liquid storage tank heat pump system 100A flows through the first flow path which only serves as a refrigerant passage, the second flow path and the fourth flow path circulate the refrigerant in parallel, thereby cooling the front and rear of the vehicle cabin at the same time.

[0086] Similar to the oil return control in the first to third modes, in the fourth mode, the controller also detects and calculates whether oil accumulation occurs in the second or fourth flow path, and performs the following control when oil accumulation occurs.

[0087] That is, in the fourth mode, when the liquid storage tank heat pump system 100A determines that oil accumulation occurs in the second flow path, the controller closes the fourth electronic expansion valve 42 on the fourth flow path, and at the same time increases the opening of the second electronic expansion valve 22 in a form in which the opening increase amount of the second electronic expansion valve 22 is equal to the opening closing amount of the fourth electronic expansion valve 42, thereby executing the oil return control for returning the lubricating oil accumulated in the second flow path to the compressor 1. When it is determined that oil accumulation occurs in the fourth flow path, the controller closes the second electronic expansion valve 22 on the second flow path, and at the same time increases the opening of the fourth electronic expansion valve 42 in a form in which the opening increase amount of the fourth electronic expansion valve 42 is equal to the opening closing amount of the second electronic expansion valve 22, thereby executing the oil return control for returning the lubricating oil accumulated in the fourth flow path to the compressor 1. After the oil return control continues for a predetermined time (for example, 30 seconds), the controller opens the electronic expansion valve on the flow path without oil accumulation that is closed due to the oil return control to the original opening, and at the same time reduces the opening of the electronic expansion valve in the oil accumulation flow path to the original state. Therefore, the receiver heat pump system 100A can perform oil return control for returning the lubricating oil accumulated in the flow path to the compressor 1 by adjusting the opening of the electronic expansion valve in each flow path in the fourth mode.

[0088] It should be noted that the present invention is not limited to the above-mentioned heat pump air-conditioning system with a liquid storage tank. Figure 4 is a schematic structural diagram of a vehicle heat pump air conditioning system according to another embodiment of the present invention, specifically, Figure 4 A heat pump air conditioning system with a gas-liquid separator (hereinafter referred to as a “gas-liquid separator heat pump system”) 200 is shown.

[0089] In the gas-liquid separator heat pump system 200, the first to third flow paths, the bypass pipeline, and the connecting pipeline are respectively connected to the downstream side of the radiator 2, and a gas-liquid separator 5 for separating the refrigerant gas and liquid to discharge the liquid refrigerant is provided, and a first gas-liquid separation pipeline and a second gas-liquid separation pipeline are respectively connected to the inlet and outlet of the gas-liquid separator 5. Specifically, Figure 4As shown, multiple nodes are formed in the loop, and these nodes can be diversion points or confluence points according to the refrigerant flow conditions. Multi-way valves can be set at these nodes to divert the flow path. On the downstream side of the heat radiator 2, the first gas-liquid separation pipeline extends from node F to node G. A gas-liquid separator 5 is set at the end of the first gas-liquid separation pipeline. The first gas-liquid separation pipeline extends into the inlet of the gas-liquid separator 5. A third solenoid valve 3c and a throttle are set on the first gas-liquid separation pipeline. The second gas-liquid separation pipeline extends from the outlet of the gas-liquid separator 5 to node I. The second gas-liquid separation pipeline is provided with a first check valve 61. The first check valve 61 allows the refrigerant to flow from the outlet of the gas-liquid separator 5 to the inlet of the first electronic expansion valve 12 described later and prevents its reverse flow. The first flow path extends from node I to node J. The first electronic expansion valve 12 and the outdoor heat exchanger 11 are sequentially arranged on the first flow path along the refrigerant flow direction. The connecting pipeline extends from node J to node K' on the downstream side of the outdoor heat exchanger 11, and a second solenoid valve 3b is arranged on the connecting pipeline. The connecting pipeline further extends from node K' to node K, and a third check valve 63 is arranged on the pipeline to allow flow from node K' to node K and prevent reverse flow. A compressor 1 and a heat radiator 2 are arranged in sequence between node K and node F. A second flow path is branched from node H' to node K' on the above-mentioned second gas-liquid separation pipeline, and a third flow path is branched from node H to node K. A second electronic expansion valve 22 and a front evaporator 21 are arranged in sequence along the refrigerant flow direction on the second flow path, and a third electronic expansion valve 32 and a refrigerant-water heat exchanger 31 are arranged in sequence along the refrigerant flow direction on the third flow path. In addition, a first bypass pipeline is branched from node F to node I on the downstream side of the heat radiator 2, and a first solenoid valve 3a is arranged on the first bypass pipeline. A second bypass line extending from node J to node G is also branched out between the outdoor heat exchanger 11 and the second solenoid valve 3b. A second check valve 62 and a throttle are provided on the second bypass line. The second check valve 62 allows the refrigerant to flow from node J to node G while preventing the refrigerant from flowing in the opposite direction.

[0090] Specifically, Figure 4As shown, a compressor 1 for compressing refrigerant and a radiator 2 for heating the interior of a vehicle by heat exchange are provided in a gas-liquid separator heat pump system 200. On the downstream side of the radiator 2, a first gas-liquid separation pipeline, a gas-liquid separator 5, a second gas-liquid separation pipeline, a first flow path and a connecting pipeline are connected in sequence. The second flow path and the third flow path are arranged in parallel in the form of one end connected to the outlet of the gas-liquid separator 5 on the pipeline and the other end directly connected to the suction port of the compressor 1. In addition, since the circuit is provided with a first bypass line capable of bypassing the refrigerant from node F to node I and a second bypass line capable of bypassing the refrigerant from node J to node G as described above, when the second solenoid valve 3b and the third solenoid valve 3c are closed, the first gas-liquid separation line and the connecting line are blocked. At this time, on the downstream side of the heat emitter 2, the first bypass line, the first flow path, the second bypass line, the gas-liquid separator 5 and the second gas-liquid separation line are connected in sequence, and the second flow path and the third flow path are branched out in parallel at the nodes H' and H of the second gas-liquid separation line, and the refrigerant flows through the second flow path and the third flow path respectively and then merges and returns to the compressor 1.

[0091] In addition, the gas-liquid separator heat pump system 200 also includes a controller (not shown). The controller issues control instructions to each electronic expansion valve, each solenoid valve, etc. in the gas-liquid separator heat pump system 200 to control the opening and closing status of each valve to realize different thermal management modes, and adjusts the opening size of each valve to meet the workload in these thermal management modes.

[0092] In this embodiment, the gas-liquid separator heat pump system 200 can control the flow conditions of the refrigerant in the vehicle heat pump air-conditioning system by selectively connecting or blocking each flow path, thereby realizing the above-mentioned first to third modes to meet the thermal management requirements of the vehicle.

[0093] Specifically, when the first solenoid valve 3a is closed, the second solenoid valve 3b and the third solenoid valve 3c are opened, the second electronic expansion valve 22 is in a closed state and the third electronic expansion valve 32 is in an open state, the refrigerant discharged from the compressor 1 releases heat in the heat release device 2, and then flows into the gas-liquid separator 5. At this time, the first flow path and the third flow path circulate the liquid refrigerant discharged from the gas-liquid separator 5 in parallel, thereby heating the vehicle while recovering waste heat, that is, executing the first mode as a waste heat recovery mode while heating the vehicle.

[0094] When the first solenoid valve 3a is closed, the second solenoid valve 3b and the third solenoid valve 3c are opened, the second electronic expansion valve 22 is in an open state and the third electronic expansion valve 32 is in a closed state, the refrigerant discharged from the compressor 1 releases heat in the heat release device 2, and then flows into the gas-liquid separator 5. At this time, the first flow path and the second flow path circulate the liquid refrigerant discharged from the gas-liquid separator 5 in parallel, thereby dehumidifying the air in the vehicle interior while heating the vehicle interior, that is, executing the second mode as a dehumidification and heating mode in the vehicle interior.

[0095] When the first solenoid valve 3a is open and the second solenoid valve 3b and the third solenoid valve 3c are closed, the radiator 2 functions only as a refrigerant passage. At this time, the second electronic expansion valve 22 and the third electronic expansion valve 32 are in an open state, and the refrigerant discharged from the compressor 1 is converted into a high-pressure liquid by dissipating heat through the outdoor heat exchanger 11, and then flows into the gas-liquid separator 5 through the first electronic expansion valve 12. At this time, the second flow path and the third flow path circulate the liquid refrigerant discharged from the gas-liquid separator 5 in parallel, thereby cooling the battery while cooling the vehicle interior, that is, executing the third mode as a vehicle interior cooling and battery cooling mode.

[0096] In order to prevent the compressor from being short of lubricating oil due to lack of lubricating oil, the controller of the gas-liquid separator heat pump system 200 also repeatedly performs the following steps in the first to third modes: Figure 2 The oil return control shown in FIG. 1 is a control method for controlling the oil return of a part of the plurality of flow paths through which the refrigerant flows in parallel. That is, when oil accumulation occurs in a part of the flow paths through which the refrigerant flows in parallel, the controller performs the oil return control to close the electronic expansion valves on the other flow paths through which the refrigerant flows in parallel to increase the refrigerant flow rate on the flow path through which the oil accumulation occurs, so that the accumulated lubricating oil flows back to the compressor 1. The specific control method is basically the same as the oil return control of the first to third modes in the liquid storage tank heat pump system 100, and only the differences are described here.

[0097] Specifically, in the gas-liquid separator heat pump system 200, when the refrigerant-water heat exchanger 31 is used for waste heat recovery or battery cooling, in order to prevent overcooling or liquid return in the refrigerant-water heat exchanger 31, the controller also controls the first electronic expansion valve 12 to close for a specified time when it is determined that oil accumulation occurs in the third flow path and the temperature of the cooling water side in the refrigerant-water heat exchanger 31 is above a preset specified value in the first mode and the third mode. When the temperature of the cooling water side is lower than the above specified value, the third electronic expansion valve 32 is closed until the temperature of the cooling water side returns to above the specified value. This can prevent the liquid refrigerant from being sucked into the compressor 1 and causing damage to the compressor 1.

[0098] Figure 52 is a schematic diagram of the structure of a gas-liquid separator heat pump system 200A as a modified example of the gas-liquid separator heat pump system 200. The gas-liquid separator heat pump system 200A has the same structure as the gas-liquid separator heat pump system 200 except that a fourth flow path is provided. Figure 5 The structure of the gas-liquid separator heat pump system 200A will be described.

[0099] Specifically, if Figure 5 As shown, a node L is also formed on the second flow path, and the fourth flow path is arranged in parallel with the second and third flow paths in the form of extending from the node L to the node K'. The fourth electronic expansion valve 42 and the rear evaporator 41 are arranged in sequence along the refrigerant flow direction on the fourth flow path. In this embodiment, the node L is not limited to being formed on the second flow path, and can also be formed on the second gas-liquid separation pipeline in the form of being located between the node H and the node H'. In this case, the fourth flow path is also arranged in parallel with the second and third flow paths. As long as the controller controls the fourth electronic expansion valve 42 to close to block the fourth flow path, the gas-liquid separator heat pump system 200A has the same structure as the gas-liquid separator heat pump system 200, so the above-mentioned first to third modes can also be executed.

[0100] By setting the fourth flow path, the gas-liquid separator heat pump system 200A can execute the fourth mode of cooling the front and rear of the vehicle cabin at the same time. The flow mode of the refrigerant in the vehicle heat pump air conditioning system in the fourth mode is similar to the third mode. The controller opens the first solenoid valve 3a and closes the second solenoid valve 3b and the third solenoid valve 3c. At this time, the heat radiator 2 only acts as a refrigerant passage. The controller also closes the third electronic expansion valve 32 on the third flow path to block the third flow path, and makes the second electronic expansion valve 22 and the fourth electronic expansion valve 42 in an open state. The refrigerant discharged from the compressor 1 passes through the outdoor heat exchanger 11 to release heat and becomes a high-pressure liquid, and then flows into the gas-liquid separator 5. At this time, the second flow path and the fourth flow path circulate the liquid refrigerant discharged from the gas-liquid separator 5 in parallel, thereby cooling the front and rear of the vehicle cabin at the same time, that is, executing the fourth mode as a simultaneous cooling mode for the front and rear seats.

[0101] Similarly, in the fourth mode, the controller of the gas-liquid separator heat pump system 200A also detects and calculates whether oil accumulation occurs in the second or fourth flow path. Figure 2 The specific control method is the same as the oil return control of the fourth mode in the liquid storage tank heat pump system 100A, and the description is omitted here.

[0102] According to the present invention, an electronic expansion valve is arranged before each evaporator and heat exchanger, and a controller is used to perform oil return control when oil accumulation occurs in a certain flow path, so that the accumulated lubricating oil returns to the compressor. Therefore, the intake oil circulation rate and oil circulation amount of the compressor can be guaranteed, and the quality of the compressor can be guaranteed.

[0103] This function ensures the circulation rate and circulation volume of the compressor's lubricating oil, prevents the compressor from being damaged by oil starvation or the inflow of liquid refrigerant during operation, and ensures the normal operation of the compressor during the vehicle's thermal management process.

[0104] The above specific implementations further describe the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above is only a specific implementation of the present invention and is not limited to the protection scope of the present invention. Without departing from the purpose of the basic characteristics of the present invention, the present invention can be embodied in various forms. Therefore, the implementation forms in the present invention are used for illustration rather than limitation. Since the scope of the present invention is limited by the claims rather than the specification, and all changes within the scope defined by the claims or within the equivalent scope of the scope defined by the claims should be understood to be included in the claims. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A vehicle heat pump air conditioning system, characterized in that: include: compressor; Heat release device; A first flow path having an outdoor heat exchanger and a first electronic expansion valve located upstream thereof; A second flow path provided with a front evaporator and a second electronic expansion valve on the upstream side thereof; A third flow path having a refrigerant-water heat exchanger and a third electronic expansion valve located upstream thereof; A first bypass pipeline provided with a first solenoid valve; A communication pipeline provided with a second solenoid valve; Gas-liquid separator; A first gas-liquid separation pipeline connected to the inlet of the gas-liquid separator and provided with a third solenoid valve; A second gas-liquid separation pipeline connected to the outlet of the gas-liquid separator and provided with a first check valve; and A second bypass pipeline provided with a second check valve; In the first mode, the first solenoid valve is closed, the second solenoid valve and the third solenoid valve are opened, the second electronic expansion valve is in a closed state, and the third electronic expansion valve is in an open state, the refrigerant flowing out of the radiator flows into the gas-liquid separator, and the first flow path and the connecting pipe are connected in series, and then the liquid refrigerant discharged from the gas-liquid separator is circulated in parallel with the third flow path; In the second mode, the first solenoid valve is closed, the second solenoid valve and the third solenoid valve are opened, the second electronic expansion valve is in an open state and the third electronic expansion valve is in a closed state, the refrigerant flowing out of the radiator flows into the gas-liquid separator, and the first flow path and the second flow path flow the liquid refrigerant discharged from the gas-liquid separator in parallel; In the third mode, the first solenoid valve is open, the second solenoid valve and the third solenoid valve are closed, the second electronic expansion valve and the third electronic expansion valve are in an open state, the refrigerant flowing out of the radiator flows into the gas-liquid separator after flowing through the first flow path, and the second flow path and the third flow path flow the liquid refrigerant discharged from the gas-liquid separator in parallel; Also includes a controller for controlling at least any one of the first electronic expansion valve, the second electronic expansion valve and the third electronic expansion valve; In the first to third modes, when oil accumulation occurs in a part of the multiple flow paths through which the refrigerant circulates in parallel, the controller performs oil return control to increase the flow rate of the refrigerant in the flow path where oil accumulation occurs by closing the electronic expansion valves on the other flow paths through which the refrigerant circulates in parallel; In the first mode, when oil accumulation occurs in the third flow path, when the cooling water temperature in the refrigerant-water heat exchanger is above a preset specified value, the controller controls the first electronic expansion valve to close for a specified time, and when the cooling water side temperature is lower than the specified value, the controller controls the third electronic expansion valve to close until the cooling water side temperature returns to above the specified value.

2. A vehicle heat pump air conditioning system, characterized in that: include: compressor; Heat release device; A first flow path having an outdoor heat exchanger and a first electronic expansion valve located upstream thereof; A second flow path provided with a front evaporator and a second electronic expansion valve on the upstream side thereof; A third flow path having a refrigerant-water heat exchanger and a third electronic expansion valve located upstream thereof; A first bypass pipeline provided with a first solenoid valve; A communication pipeline provided with a second solenoid valve; Gas-liquid separator; A first gas-liquid separation pipeline connected to the inlet of the gas-liquid separator and provided with a third solenoid valve; A second gas-liquid separation pipeline connected to the outlet of the gas-liquid separator and provided with a first check valve; and A second bypass pipeline provided with a second check valve; In the first mode, the first solenoid valve is closed, the second solenoid valve and the third solenoid valve are opened, the second electronic expansion valve is in a closed state, and the third electronic expansion valve is in an open state, the refrigerant flowing out of the radiator flows into the gas-liquid separator, and the first flow path and the connecting pipe are connected in series, and then the liquid refrigerant discharged from the gas-liquid separator is circulated in parallel with the third flow path; In the second mode, the first solenoid valve is closed, the second solenoid valve and the third solenoid valve are opened, the second electronic expansion valve is in an open state and the third electronic expansion valve is in a closed state, the refrigerant flowing out of the radiator flows into the gas-liquid separator, and the first flow path and the second flow path flow the liquid refrigerant discharged from the gas-liquid separator in parallel; In the third mode, the first solenoid valve is open, the second solenoid valve and the third solenoid valve are closed, the second electronic expansion valve and the third electronic expansion valve are in an open state, the refrigerant flowing out of the radiator flows into the gas-liquid separator after flowing through the first flow path, and the second flow path and the third flow path flow the liquid refrigerant discharged from the gas-liquid separator in parallel; Also includes a controller for controlling at least any one of the first electronic expansion valve, the second electronic expansion valve and the third electronic expansion valve; In the first to third modes, when oil accumulation occurs in a part of the multiple flow paths through which the refrigerant circulates in parallel, the controller performs oil return control to increase the flow rate of the refrigerant in the flow path where oil accumulation occurs by closing the electronic expansion valves on the other flow paths through which the refrigerant circulates in parallel; In the third mode, when oil accumulation occurs in the third flow path, when the cooling water temperature in the refrigerant-water heat exchanger is above a preset specified value, the controller controls the second electronic expansion valve to close for a specified time, and when the cooling water side temperature is lower than the specified value, the controller controls the third electronic expansion valve to close until the cooling water side temperature returns to above the specified value.

3. The vehicle heat pump air conditioning system according to claim 1 or 2, characterized in that: Also included is a fourth flow path provided with a rear evaporator and a fourth electronic expansion valve located upstream of the rear evaporator; In the first to third modes, the fourth electronic expansion valve is in a closed state; The vehicle heat pump air conditioning system further operates in a fourth mode; In the fourth mode, the first solenoid valve is open, the second solenoid valve and the third solenoid valve are closed, the third electronic expansion valve is in a closed state, the second electronic expansion valve and the fourth electronic expansion valve are in an open state, the refrigerant flows into the gas-liquid separator after flowing through the first flow path, and the second flow path and the fourth flow path flow the liquid refrigerant discharged from the gas-liquid separator in parallel; The controller also controls the fourth electronic expansion valve; In the fourth mode, when oil accumulation occurs in a part of the multiple flow paths through which the refrigerant circulates in parallel, the controller performs oil return control to close the electronic expansion valves on other flow paths among the multiple flow paths through which the refrigerant circulates in parallel to increase the flow rate of the refrigerant on the flow path where oil accumulation occurs.

4. The vehicle heat pump air conditioning system according to claim 1 or 2, characterized in that: In the first mode, When oil accumulation occurs in the first flow path, the controller closes the third electronic expansion valve to increase the flow rate of the refrigerant flowing through the first flow path. When oil accumulation occurs in the third flow path, the controller closes the first electronic expansion valve to increase the flow rate of the refrigerant flowing through the third flow path.

5. The vehicle heat pump air conditioning system according to claim 1 or 2, characterized in that: In the second mode, When oil accumulation occurs in the first flow path, the controller closes the second electronic expansion valve to increase the flow rate of the refrigerant flowing through the first flow path. When oil accumulation occurs in the second flow path, the controller closes the first electronic expansion valve to increase the flow rate of the refrigerant flowing through the second flow path.

6. The vehicle heat pump air conditioning system according to claim 1 or 2, characterized in that: In the third mode, When oil accumulation occurs in the second flow path, the controller closes the third electronic expansion valve to increase the flow rate of the refrigerant flowing through the second flow path. When oil accumulation occurs in the third flow path, the controller closes the second electronic expansion valve to increase the flow rate of the refrigerant flowing through the third flow path.

7. The vehicle heat pump air conditioning system according to claim 3, characterized in that: In the fourth mode, When oil accumulation occurs in the second flow path, the controller closes the fourth electronic expansion valve to increase the flow rate of the refrigerant flowing through the second flow path. When oil accumulation occurs in the fourth flow path, the controller closes the second electronic expansion valve to increase the flow rate of the refrigerant flowing through the fourth flow path.

8. The vehicle heat pump air conditioning system according to claim 4, characterized in that: When oil accumulation occurs in the first flow path, the controller closes the third electronic expansion valve and increases the opening of the first electronic expansion valve at the same time; When oil accumulation occurs in the third flow path, the controller closes the first electronic expansion valve and increases the opening of the third electronic expansion valve at the same time.

9. The vehicle heat pump air conditioning system according to claim 5, characterized in that: When oil accumulation occurs in the first flow path, the controller closes the second electronic expansion valve and increases the opening of the first electronic expansion valve at the same time; When oil accumulation occurs in the second flow path, the controller closes the first electronic expansion valve and increases the opening of the second electronic expansion valve at the same time.

10. The vehicle heat pump air conditioning system according to claim 6, characterized in that: When oil accumulation occurs in the second flow path, the controller closes the third electronic expansion valve and increases the opening of the second electronic expansion valve at the same time; When oil accumulation occurs in the third flow path, the controller closes the second electronic expansion valve and increases the opening of the third electronic expansion valve at the same time.

11. The vehicle heat pump air conditioning system according to claim 7, characterized in that: When oil accumulation occurs in the second flow path, the controller closes the fourth electronic expansion valve and increases the opening of the second electronic expansion valve at the same time; When oil accumulation occurs in the fourth flow path, the controller closes the second electronic expansion valve and increases the opening of the fourth electronic expansion valve at the same time.

12. The vehicle heat pump air conditioning system according to any one of claims 8 to 11, characterized in that: In the plurality of flow paths through which the refrigerant flows in parallel, the controller performs oil return control in such a manner that an increase in the opening degree of the electronic expansion valve on the flow path where oil accumulation occurs is equal to an increase in the opening degree of the electronic expansion valve on the remaining flow paths.

13. The vehicle heat pump air conditioning system according to claim 1 or 2, characterized in that: The controller releases the oil return control after executing the oil return control for a predetermined period of time.

14. The vehicle heat pump air conditioning system according to claim 3, characterized in that: The first mode is a mode of heating the interior of the vehicle and recovering waste heat simultaneously; The second mode is a mode of dehumidifying and heating the vehicle at the same time; The third mode is a mode of cooling the interior of the vehicle and cooling the battery simultaneously; The fourth mode is a simultaneous cooling mode for the front seats and the rear seats.

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