Heat pump system for vehicle, and vehicle

Abstract

A heat pump system for a vehicle, comprising: a compressor (1a), compressing a refrigerant; a refrigerant circuit, forming a closed-loop flow path of the refrigerant; a plurality of switching valves, comprising at least one of a 2 / 2-way valve, a 3 / 2-way valve, and a 4 / 2-way valve, wherein the 2 / 2-way valve is configured to be controlled to block or open the flow path, the 3 / 2-way valve is configured to be controlled to switch the flow path, and the 4 / 2-way valve is configured to be controlled to reverse heat exchange; and a first pilot valve (19), simultaneously controlling at least two of the plurality of switching valves. By using the heat pump system, the total number of solenoid actuators and the number of valves can be decreased. Thus, the mounting space is reduced, and the workload for wiring and controller calibration is reduced.

Description

Heat pump system for a vehicle and vehicle TECHNICAL FIELD

[0001] The present invention relates to a heat pump system for a vehicle and a vehicle. BACKGROUND

[0002] A heat pump system for a vehicle allows switching between a winter cabin heating mode (heat pump) to a summer cabin cooling mode (air conditioning). As a variety of operating topology scenarios need to be covered, especially if the heat pump system has to account for heating and cooling of the cabin, heating and cooling of the battery and cooling of the power electronics unit, the heat pump system has to be able to extract thermal energy from the environment (i.e. air source heat pump) or from the waste heat of the power electronics unit (PEU) and the battery or from the electric motor (Emotor) if present. This means that there are many topology and flow branch switches.

[0003] To accommodate the different modes of operation, car manufacturers usually design multiple system layouts. These layouts use multiple solenoid valves to control the switching between heat pump and air conditioning and multiple valves to precisely control the flow of refrigerant in the heat source and sink branches, including electronic expansion valves (EXV), shut-off valves (SOV) and check valves. Shut-off valves are key components to enable branch shut-off, they can either shut off or allow the flow of refrigerant through a specific path. In addition, to direct the flow of refrigerant at cross-over points in the system or where backflow can occur, a combination of 2 / 2 shut-off valves and check valves is used.

[0004] Fig. 1 is a schematic diagram of a layout of a heat pump system for a vehicle according to the prior art. As shown in Fig. 1, the heat pump system provides the ability to provide 11 modes of operation. At least 3 electronic expansion valves, 3 check valves and 6 shut-off valves are used in the heat pump system, i.e. at least 6 solenoid actuators and 3 electronic expansion valve actuators are required. As described in the prior art, the increase in the number of installed shut-off valves with solenoid actuators requires an increased installation or installation space and an increased effort for wiring and controller calibration. SUMMARY

[0005] It is an object of the present invention to provide a heat pump system for a vehicle and a vehicle with a reduced number of solenoid actuators.

[0006] The present invention provides a heat pump system for a vehicle, comprising:

[0007] a compressor, which compresses a refrigerant;

[0008] A refrigerant circuit forms a closed loop flow path of a refrigerant.

[0009] A plurality of switching valves includes at least one of a 2 / 2-way valve, a 3 / 2-way valve, and a 4 / 2-way valve, wherein the 2 / 2-way valve is configured to be controlled to shut off or turn on a flow path, the 3 / 2-way valve is configured to be controlled to switch a flow path, and the 4 / 2-way valve is configured to be controlled to reverse a heat exchange.

[0010] A first pilot valve controls at least two of the plurality of switching valves.

[0011] According to an embodiment of the present application, the first pilot valve is a 3 / 2-way valve having three ports, a first port connected to a discharge end of the compressor, a second port connected to a suction end of the compressor, and a third port leading to pilot passages of the at least two switching valves, respectively.

[0012] According to an embodiment of the present application, the heat pump system further includes a plurality of heat exchange devices including a first heat exchange device, wherein

[0013] The plurality of switching valves includes a first 4 / 2-way valve having four interfaces, a first interface connected to the discharge end of the compressor, a second interface connected to the suction end of the compressor,

[0014] The first heat exchange device is connected to the third interface and the fourth interface, respectively, and absorbs or releases heat according to a circulation direction of the refrigerant.

[0015] According to an embodiment of the present application, the plurality of heat exchange devices further includes a second heat exchange device, and the plurality of switching valves further includes a first 2 / 2-way valve and a first 3 / 2-way valve,

[0016] The first 2 / 2-way valve is located on a flow path between the second interface of the first 4 / 2-way valve and the suction end of the compressor,

[0017] The first 3 / 2-way valve has three ports, a first port connected to the discharge end of the compressor, a second port connected to the first interface of the 4 / 2-way valve, and a third port connected to the suction end of the compressor,

[0018] The second heat exchange device is located on a flow path between the third port and the suction end,

[0019] The first pilot valve controls the first 2 / 2-way valve and the first 3 / 2-way valve so as to switch series and parallel connection between the first heat exchange device and the second heat exchange device.

[0020] According to an embodiment of the present application, the plurality of heat exchange devices further includes a third heat exchange device, and the plurality of switching valves further includes a second 2 / 2-way valve, a second 3 / 2-way valve, and a second 4 / 2-way valve,

[0021] The second 4 / 2-way valve has four openings, a first opening connected to the discharge end of the compressor, a second opening connected to the suction end of the compressor,

[0022] The second 2 / 2-way valve is located on a flow path between the second opening and the suction end of the compressor,

[0023] The third heat exchange device is connected to the third opening and the fourth opening, respectively, and absorbs or releases heat according to the circulation direction of the refrigerant,

[0024] The second 3 / 2-way valve has three flow openings, a first flow opening connected to the first opening of the second 4 / 2-way valve, a second flow opening connected to the second opening of the second 4 / 2-way valve, and a third flow opening connected to the discharge end of the compressor,

[0025] The first pilot valve controls the second 2 / 2-way valve and the second 3 / 2-way valve, so as to switch the series-parallel connection between the first heat exchange device and the third heat exchange device.

[0026] According to an embodiment of the present application, the heat pump system further comprises a second pilot valve, wherein the first pilot valve simultaneously controls the first 2 / 2-way valve, the first 3 / 2-way valve, and the first 4 / 2-way valve, and the second pilot valve simultaneously controls the second 2 / 2-way valve, the second 3 / 2-way valve, and the second 4 / 2-way valve.

[0027] According to an embodiment of the present application, the second pilot valve is a 3 / 2-way valve having three valve openings, a first valve opening connected to the discharge end of the compressor, a second valve opening connected to the suction end of the compressor, and a third valve opening leading to the pilot passage of the second 2 / 2-way valve, the second 3 / 2-way valve, and the second 4 / 2-way valve.

[0028] According to an embodiment of the present application, the heat pump system further comprises a plurality of expansion valves connected to the plurality of heat exchange devices, respectively, and configured to be able to open the flow path, close the flow path, and throttle the refrigerant in proportion.

[0029] According to an embodiment of the present application, the third heat exchange device is a front-end external heat exchanger.

[0030] According to an embodiment of the present application, the first heat exchange device comprises a battery cooler and an evaporator connected in parallel.

[0031] According to an embodiment of the present application, the second heat exchange device comprises a power electronic unit cooler and a motor cooler connected in series.

[0032] Another aspect of the present application provides a vehicle comprising the heat pump system for a vehicle according to any one of the above embodiments.

[0033] The heat pump system of the present application combines simultaneous movements of various SOVs and check valves into a switching valve controlled by a first pilot valve, i.e., 2 / 2-way valve, 3 / 2-way valve, and 4 / 2-way valve. In this way, the number of electromagnetic actuators of multiple switching valves can be combined onto the same control valve, and in this way the total number of electromagnetic actuators can be reduced. In addition, since the 2 / 2-way valve, 3 / 2-way valve, and 4 / 2-way valve replace the SOV valves, the number of valves can also be reduced. Therefore, the heat pump system of the present application reduces the installation space, and reduces the wiring and controller calibration workload. BRIEF DESCRIPTION OF DRAWINGS

[0034] FIG. 1 is a schematic diagram of a layout of a heat pump system for a vehicle according to the related art.

[0035] FIG. 2 is a schematic diagram of an expansion valve according to an embodiment of the present application.

[0036] FIG. 3A is a schematic diagram of a first pilot valve in a closed state according to an embodiment of the present application.

[0037] FIG. 3B is a schematic diagram of a first pilot valve in an open state according to an embodiment of the present application.

[0038] FIG. 4A is a schematic diagram of a second pilot valve in a closed state according to an embodiment of the present application.

[0039] FIG. 4B is a schematic diagram of a second pilot valve in an open state according to an embodiment of the present application.

[0040] FIG. 5 is a schematic diagram of a two-position 3 / 2-way valve derived into a two-position 2 / 2-way valve according to an embodiment of the present application.

[0041] FIG. 6 is a state diagram of a heat pump system for a vehicle in a first operation mode according to an embodiment of the present application.

[0042] FIG. 7 is a state diagram of a heat pump system for a vehicle in a second operation mode according to an embodiment of the present application.

[0043] FIG. 8 is a state diagram of a heat pump system for a vehicle in a third operation mode according to an embodiment of the present application.

[0044] FIG. 9 is a state diagram of a heat pump system for a vehicle in a fourth operation mode according to an embodiment of the present application.

[0045] FIG. 10 is a state diagram of a heat pump system for a vehicle in a fifth operation mode according to an embodiment of the present application.

[0046] FIG. 11 is a state diagram of a heat pump system for a vehicle in a sixth operation mode according to an embodiment of the present application.

[0047] Fig. 12 is a state diagram of a heat pump system for a vehicle in a seventh operation mode according to an embodiment of the present application.

[0048] Fig. 13 is a state diagram of a heat pump system for a vehicle in an eighth operation mode according to an embodiment of the present application.

[0049] Fig. 14 is a state diagram of a heat pump system for a vehicle in a ninth operation mode according to an embodiment of the present application.

[0050] Fig. 15 is a state diagram of a heat pump system for a vehicle in a tenth operation mode according to an embodiment of the present application.

[0051] Fig. 16 is a state diagram of a heat pump system for a vehicle in an eleventh operation mode according to an embodiment of the present application.

[0052] Fig. 17 is a state diagram of a heat pump system for a vehicle in a twelfth operation mode according to an embodiment of the present application.

[0053] Fig. 18A is a structural diagram of a heat pump system for a vehicle according to a first comparative example.

[0054] Fig. 18B is a structural diagram of a heat pump system for a vehicle according to a second comparative example.

[0055] In the drawings: 1a, compressor; 1b, receiver drier; 2, condenser; 3, second 4 / 2-way valve; 4, first expansion valve; 5, front-end external heat exchanger; 6, evaporator; 7, battery cooler; 8, power electronics unit cooler; 9, electric motor cooler; 10, second 3 / 2-way valve; 11, second expansion valve; 12, third expansion valve; 13, fourth expansion valve; 14, first 3 / 2-way valve; 15, first 4 / 2-way valve; 16, first 2 / 2-way valve; 17, second 2 / 2-way valve; 18, second pilot valve; 19, first pilot valve. DETAILED DESCRIPTION

[0056] The technical solutions in the embodiments of the present application will be apparently and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without any creative effort belong to the protection scope of the present application.

[0057] Embodiments of the present invention provide a heat pump system for a vehicle. Referring to FIGS. 6 to 17, the heat pump system includes a compressor 1a, a refrigerant circuit, a plurality of switching valves, and a first pilot valve 19. The compressor 1a is for compressing a refrigerant, increasing its pressure and temperature, and has a suction end and a discharge end. The refrigerant circuit forms a closed loop flow path. The plurality of switching valves are selected from at least one of a 2 / 2-way valve, a 3 / 2-way valve, and a 4 / 2-way valve. The 2 / 2-way valve is configured to be controlled to shut off or turn on a flow path, the 3 / 2-way valve is configured to be controlled to switch between two branches of a flow path, and the 4 / 2-way valve is configured to be controlled to reverse a heat exchange. The first pilot valve 19 controls at least two of the plurality of switching valves simultaneously.

[0058] The prior art generally requires a plurality of electromagnetic actuators to actuate a plurality of SOVs of a heat pump system, respectively. The present inventor found that many SOVs work simultaneously to achieve a specific topology switching, which means that several SOV actuators are in an open or closed state at the same time. Therefore, the heat pump system of the present invention combines the simultaneous movements of various SOVs and check valves into switching valves, i.e., 2 / 2-way valves, 3 / 2-way valves, and 4 / 2-way valves, controlled by the first pilot valve 19. In this way, the number of electromagnetic actuators of the plurality of switching valves can be combined onto the same control valve, by which the total number of electromagnetic actuators can be reduced. Furthermore, since the 2 / 2-way valves, 3 / 2-way valves, and 4 / 2-way valves replace the SOV valves, the number of valves can also be reduced. Therefore, the heat pump system of the present invention reduces the installation space and the workload of wiring and controller calibration.

[0059] In one embodiment, the first pilot valve 19 is a 3 / 2-way valve having three ports, a first port connected to the discharge end of the compressor 1a, a second port connected to the suction end of the compressor 1a, and a third port leading to, i.e., connected to, at least two switching valve pilot passages. FIGS. 3A and 3B show schematic views of the first pilot valve 19 in a closed state and an open state. As shown in FIGS. 3A and 3B, the first pilot valve 19 is in a TB flow logic in the closed state and in a PB flow logic in the open state.

[0060] The heat pump system further comprises a first heat exchange device. The plurality of switching valves comprises a first 4 / 2-way valve 15 having four ports 15P, 15T, 15a, 15b, a first port 15P connected to the discharge end of the compressor la, a second port 15T connected to the suction end of the compressor la, and the first heat exchange device connected to the third port 15a and the fourth port 15b, that is, the first heat exchange device is connected to both the third port and the fourth port, and absorbs heat or rejects heat according to the circulating direction of the refrigerant. In one embodiment, the first heat exchange device comprises a battery cooler 7 and an evaporator 6 connected in parallel. The first 4 / 2-way valve 15 can reverse the flow of refrigerant at the battery cooler 7 and the evaporator 6. This means that the evaporator 6 and the battery cooler 7 either absorb heat at the same time or reject heat at the same time, or one of them is closed, and there is no case where one absorbs heat and the other rejects heat. The battery cooler 7 is responsible for absorbing heat from the battery or preheating the battery when needed, and the evaporator 6 can perform heat absorption or heat rejection operations.

[0061] The heat pump system further comprises a second heat exchange device, and the plurality of switching valves further comprises a first 2 / 2-way valve 16 and a first 3 / 2-way valve 14. The first 2 / 2-way valve 16 is located on the flow path between the second port 15T and the suction end. The first 3 / 2-way valve 14 has three ports, a first port 14P connected to the discharge end of the compressor la, a second port 14T connected to the first port 15P of the first 4 / 2-way valve 15, and a third port 14a connected to the suction end of the compressor la. The second heat exchange device is located on the flow path between the third port 14a and the suction end. The first pilot valve 19 controls the first 2 / 2-way valve 16 and the first 3 / 2-way valve 14, so as to switch the series-parallel connection between the first heat exchange device and the second heat exchange device. Specifically, when the first port 14P is in communication with the third port 14a and the first 2 / 2-way valve 16 is on, the first heat exchange device and the second heat exchange device are arranged in parallel. When the second port 14T is in communication with the third port 14a and the first 2 / 2-way valve 16 is off, the first heat exchange device and the second heat exchange device are arranged in series. In one embodiment, the second heat exchange device comprises a power electronic unit (PEU) cooler 8 and a motor cooler 9 connected in series. For example, the power electronic unit cooler 8 is a cooling plate.

[0062] The heat pump system further comprises a second pilot valve 18, the plurality of heat exchange devices further comprises a third heat exchange device, and the plurality of switching valves further comprises a second 2 / 2-way valve 17, a second 3 / 2-way valve 10 and a second 4 / 2-way valve 3. The second 4 / 2-way valve 3 has four openings 3P, 3T, 3a, 3b, the first opening 3P is connected to the discharge end of the compressor, the second opening 3T is connected to the suction end of the compressor, and the second 2 / 2-way valve 17 is located on the flow path between the second opening 3T and the suction end. The third heat exchange device is connected to the third opening 3a and the fourth opening 3b of the second 4 / 2-way valve 3 respectively, and absorbs heat or releases heat according to the circulating direction of the refrigerant. The second 3 / 2-way valve 10 has three flow ports 10P, 10T, 10a, the first flow port 10T is connected to the first opening 3P, the second flow port 10P is connected to the second opening 3T, and the third flow port 10a is connected to the suction end of the compressor 1a. The second pilot valve 18 controls the second 2 / 2-way valve 17 and the second 3 / 2-way valve 10, so as to switch the series-parallel connection between the first heat exchange device and the third heat exchange device. Specifically, when the first flow port 10P and the third flow port 10a are communicated and the second 2 / 2-way valve 17 is cut off, the first heat exchange device and the third heat exchange device are arranged in series, and when the second flow port 10T and the third flow port 10a are communicated and the second 2 / 2-way valve 17 is connected, the first heat exchange device and the third heat exchange device are arranged in parallel.

[0063] The first pilot valve 19 controls the first 2 / 2-way valve 16, the first 3 / 2-way valve 14 and the first 4 / 2-way valve 15 simultaneously. The second pilot valve 18 controls the second 2 / 2-way valve 17, the second 3 / 2-way valve 10 and the second 4 / 2-way valve 3 simultaneously, so as to further reduce the number of electromagnetic actuators.

[0064] The second pilot valve 18 is a 3 / 2-way valve, which has three valve ports, the first valve port is connected to the discharge end of the compressor 1a, the second valve port is connected to the suction end of the compressor 1a, and the third valve port leads to the pilot passage of the second 2 / 2-way valve 17, the second 3 / 2-way valve 10 and the second 4 / 2-way valve 3.

[0065] The 2 / 2-way valve, the 3 / 2-way valve and the 4 / 2-way valve use the pressure of the refrigerant flow for force balance. By using the refrigerant flow pressure, the current required for the first pilot valve 19 and the second pilot valve 18 to maintain the state can be reduced to, for example, <0.5A. FIGS. 3A to 4B explain the force balance principle of the 3 / 2-way valve and the 4 / 2-way valve when the first pilot valve 19 and the second pilot valve 18 are opened or closed.

[0066] As shown in FIGS. 3A and 3B, when the first pilot valve 19 is in the power-off closed state, the first 3 / 2 way valve 14 is in the Pa flow logic, and the first 4 / 2 way valve 15 is in the PabT flow logic. When the first pilot valve 19 is in the power-on open state, the first 3 / 2 way valve 14 is in the Ta flow logic, and the first 4 / 2 way valve 15 is in the PbaT flow logic. As shown in FIGS. 6 to 17, the first 2 / 2 way valve 16 is a normally open valve. When the first pilot valve 19 is in the power-off closed state, the first 2 / 2 way valve 16 is in the on flow path, and when the first pilot valve 19 is in the power-on open state, the first 2 / 2 way valve 16 is in the off flow path.

[0067] As shown in FIGS. 4A and 4B, when the second pilot valve 18 is in the power-off closed state, the second 3 / 2 way valve 10 is in the Pa flow logic, and the second 4 / 2 way valve 3 is in the PbaT flow logic. When the second pilot valve 18 is in the power-on open state, the second 3 / 2 way valve 10 is in the Ta flow logic, and the second 4 / 2 way valve 3 is in the PabT flow logic. As shown in FIGS. 6 to 17, the second 2 / 2 way valve 17 is a normally closed valve, and when the second pilot valve 18 is in the closed state, the second 2 / 2 way valve 17 is in the off flow path, and when the second pilot valve 18 is in the power-on open state, the second 2 / 2 way valve 17 is in the on flow path.

[0068] The pressure drop along the switching flow path should be very small, and the effective flow diameter should be greater than 8 mm. The pressure difference of the 3 / 2 way valve and the 4 / 2 way valve balanced force surface is about 3 bar, which generates a gas force of up to 60 N on a surface with a diameter of 8 mm, which is enough to push the piston inside the 3 / 2 way valve or the 4 / 2 way valve from one end to the other end. At the same time, considering that in the heat pump mode, the difference between the high pressure and low pressure flow paths in the refrigerant system is usually greater than 3 bar, the refrigerant system can already meet the gas force potential required by the 3 / 2 and 4 / 2 way valves.

[0069] FIG. 5 shows a schematic diagram of the derivation of the 2 / 2 way NO valve and the 2 / 2 way NC valve from the 3 / 2 way valve. As shown in FIG. 5, the 2 / 2 way valve can be derived from the 3 / 2 way valve housing. By blocking the T-shaped port path and changing the spring side, a 2 / 2 normally open NO valve, i.e., the first 2 / 2 way valve 16, can be obtained. By blocking the P port path and changing the spring side, a 2 / 2 normally closed NC valve, i.e., the second 2 / 2 way valve 17, can be obtained. The housing, valve piston stroke, and effective flow diameter in the 2 / 2 way valve are the same as those in the 3 / 2 way valve. In this way, manufacturing costs can be saved.

[0070] In one embodiment, the third heat exchange device is a front end external heat exchanger 5 (FEOHX). The state of the art heat pump system does not extract heat from the environment through a front end external heat exchanger (condenser) but through a motor cooler connected to the radiator. There is no flow reversal at the front end external heat exchanger that could allow a reverse heat exchange. Therefore, the state of the art has a drawback during the cold start phase, when heat is extracted from the radiator, the operating temperature of the electric motor is also lowered, resulting in a reduction of the mechanical efficiency of the driveline. However, the front end external heat exchanger 5 of the present invention can both reject heat to the environment and absorb heat from the air for cabin heating or battery heating. Therefore, during the cold start phase, heat is extracted from the front end external heat exchanger 5, avoiding lowering the operating temperature of the electric motor, thus increasing the mechanical efficiency of the driveline.

[0071] The heat pump system comprises a plurality of expansion valves connected respectively to the plurality of heat exchange devices and configured to be able to open the flow path, close the flow path and throttle the refrigerant in proportion. In one embodiment, the heat pump system has four expansion valves, namely a first expansion valve 4, a second expansion valve 11, a third expansion valve 12 and a fourth expansion valve 13. The first expansion valve 4 is connected to the front end external heat exchanger 5, the second expansion valve 11 is connected to the battery cooler 7, the third expansion valve 12 is connected to the evaporator 6 and the fourth expansion valve 13 is connected to the power electronics unit cooler 8 and to the motor cooler 9.

[0072] Referring again to figure 1, it is known that the state of the art 2 / 2-way small diameter expansion valves can only throttle but are not good at closing the entire flow. This is mainly because the pressure difference at the expansion needle generates a very large force against the solenoid magnetic force in the fully closed condition, i.e. the solenoid itself cannot provide the required closing force. Therefore, in order to close a branch with extended operation, an additional 2 / 2-way SOV is required. This combination results in an increase in the number of electric actuators and more calibration work at the thermal management controller. For example, the reference layout in figure 1 requires 3 expansion valve actuators and 6 SOV actuators.

[0073] The expansion valves of the heat pump system of the present invention have a very large flow diameter in the fully open condition, for example > 150 mm when considering the vertical actuator stroke on a cylindrical bore 2 , with an effective hydraulic diameter > 5 mm. In contrast to the state of the art small diameter expansion valves with a very small metering needle, the large diameter expansion valves have a metering cylinder for controlling the effective flow area. There is a gas pressure balancing path inside the cylinder, which reduces the total gas force between the top and bottom of the metering surface, so the actuator force required to move the cylinder when reopening is smaller. On the contrary, the gas pressure balancing principle is difficult to apply to the needle valve of a small expansion valve, as such a gas path is difficult to drill or machine.

[0074] A large diameter expansion valve can achieve a full open, proportional throttling (expansion) or full closed condition. Figure 2 shows the difference between the three operations of a large diameter expansion valve, where the white arrow indicates the fully closed condition, the grey arrow indicates the proportional throttling and the black arrow indicates the fully open condition. In the proportional throttling condition, there is a very small flow area for throttling the refrigerant, in the fully open condition, the minimum pressure drop and reverse flow capability are obtained.

[0075] The heat pump system further comprises a receiver dryer 1 b, which is responsible for drying the refrigerant, and a condenser 2, which is located after the compressor 1 a, for cooling the high temperature and high pressure refrigerant gas, transforming it into a high pressure liquid. The heat pump system further comprises other components known to the person skilled in the art, which are not described in detail here.

[0076] The heat pump system according to the present application can cover 12 operating modes. Table 1 lists these modes. It is clear that the operating modes described below are only a part of the operating modes of the heat pump system and not all of them. All operating modes obtained by the person skilled in the art from the heat pump system, without departing from the design purpose of the heat pump system, fall within the scope of protection of the present application.

[0077] Table 1 : Topology mode table

[0078] As shown in Table 1, in the first, second and twelfth modes, the evaporator 6 operates in a heat rejection mode, in the fourth, fifth, seventh, eighth and tenth modes, in a heat absorption mode. This heat rejection is an improvement to the HVAC condenser 2, which increases the total heat transfer of the refrigerant energy to the cabin airflow. In order to achieve the switching of the operation of the evaporator 6, the backflow of the refrigerant will be optimal, so a first 4 / 2-way valve 15 is applied.

[0079] In the first, third and ninth modes, the battery cooler 7 operates in a heat rejection mode, in the sixth, seventh, tenth and eleventh modes, in a heat absorption mode. The effect of this switching is to actively warm up the battery. This heat rejection can use the heat extracted from the power electronics unit and the electric motor, or the heat extracted from the ambient air (through the front end external heat exchanger 5). In order to achieve the switching of the operation of the battery refrigerant, the backflow of the refrigerant will be optimal, so a 4 / 2-way valve is required. This flow reversal function is integrated into the first 4 / 2-way valve 15.

[0080] In the first to fourth, ninth mode, the front end external heat exchanger 5 works as an evaporator unit extracting ambient air source heat into the heat pump system. In the fifth to eighth, tenth to twelfth mode, the front end external heat exchanger 5 works as a condenser 2 discharging heat finally to the environment. To achieve the switching of the front end external heat exchanger 5 operation, a second 4 / 2-way valve 3 is applied, which operates independently from the first 4 / 2-way valve 15.

[0081] Fig. 6 to Fig. 17 are a detailed explanation of each mode and the respective valve flow logic. To simplify the illustration, the connection of the first 19 and second 18 pilot valves to the other 3 / 2-way valves, 2 / 2-way valves and 4 / 2-way valves is marked with the symbols A and B. Black A or B means energized on, while grey A or B means de-energized off.

[0082] Referring to Fig. 6, the heat pump system is in the first mode. This first mode is used to quickly pre-heat the vehicle cabin while pre-heating the battery at the same time, for example when the vehicle is parked and an external power source is connected.

[0083] In this first mode, both the first 19 and second 18 pilot valves are in the energized on state.

[0084] The first 14 and second 10 3 / 2-way valves are in Ta flow logic. The first 16 2 / 2-way valve is in the flow face closed state and the second 17 2 / 2-way valve is in the flow face open position.

[0085] Heat is extracted through the front end external heat exchanger 5 of the vehicle, then discharged to the battery through the battery cooler 7 and the cabin is heated through the evaporator 6 and condenser 2. The evaporator 6 works as an additional heater along the cabin air flow to assist in heating the air inside the cabin.

[0086] The front end external heat exchanger 5 works in evaporator mode, the first expansion valve 4 is in proportional control of the refrigerant expansion and the first 4 / 2-way valve 15 directs the high pressure refrigerant flow from the condenser 2 outlet upstream of the first expansion valve 4.

[0087] The fourth expansion valve 13 is in proportional control to extract heat from the power electronics unit and the electric motor cooler.

[0088] The second 11 and third 12 expansion valves are in full open state. The battery cooler 7 and the evaporator 6 are in heat rejection mode, so the second 4 / 2-way valve 3 directs the high pressure refrigerant flow first to the battery cooler 7 and the evaporator 6.

[0089] Referring to Fig. 7, the heat pump system is in the second mode. This second mode is intended to quickly heat the vehicle interior space without involving heating or cooling of the battery.

[0090] In this second mode, both the first pilot valve 19 and the second pilot valve 18 are in the electrically energized open state.

[0091] The first 3 / 2-way valve 14 and the second 3 / 2-way valve 10 are in Ta flow logic. The first 2 / 2-way valve 16 is in the flow area closed state, while the second 2 / 2-way valve 17 is in the flow area open position.

[0092] Heat is extracted through the front end exterior heat exchanger 5 of the vehicle's front end chiller module, then discharged to the cabin airflow through the evaporator 6 and the condenser 2. The evaporator 6 works as an additional heater along the cabin airflow to assist in heating the air inside the cabin.

[0093] The front end exterior heat exchanger 5 works in the heating mode, the first expansion valve 4 is in proportional control of the refrigerant expansion, and the first 4 / 2-way valve 15 directs the high-pressure refrigerant flow from the condenser 2 outlet upstream of the first expansion valve 4.

[0094] The fourth expansion valve 13 is in proportional control to extract heat from the power electronics unit and the electric motor chiller.

[0095] The third expansion valve 12 is in the fully open state. The evaporator 6 is in the heat rejection mode, so the second 4 / 2-way valve 3 first directs the high-pressure refrigerant flow to the evaporator 6.

[0096] The battery chiller 7 path is closed, so the second expansion valve 11 is fully closed.

[0097] Referring to Fig. 8, the heat pump system is in the third mode. The third mode is intended to pre-heat the cabin and the battery simultaneously, but less heat is delivered to the cabin airflow compared to the first or second mode.

[0098] The evaporator 6 flow is closed, and the airflow is only heated at the condenser 2.

[0099] Both the first pilot valve 19 and the second pilot valve 18 are in the electrically energized open state. The first 3 / 2-way valve 14 and the second 3 / 2-way valve 10 are in Ta flow logic. The first 2 / 2-way valve 16 is in the flow area closed state, while the second 2 / 2-way valve 17 is in the flow area open position.

[0100] Heat is extracted through the front end exterior heat exchanger 5 of the vehicle's front end chiller module, then discharged to the cabin airflow through the condenser 2. The evaporator 6 does not heat or cool the cabin airflow.

[0101] Since the front end exterior heat exchanger 5 works in the heating mode, the first expansion valve 4 is in proportional control of the refrigerant expansion, and the first 4 / 2-way valve 15 directs the high-pressure refrigerant flow from the condenser 2 outlet upstream of the first expansion valve 4.

[0102] The fourth expansion valve 13 is in proportional control to extract heat from the electric power electronics unit and the electric motor cooler.

[0103] The battery cooler 7 is in heat rejection mode, so the second 4 / 2 way valve 3 first directs the high pressure refrigerant flow to the battery cooler 7. The second expansion valve 11 is in full open state.

[0104] The evaporator 6 is off, so the third expansion valve 12 is fully closed.

[0105] Referring to Fig. 9, the heat pump system is in fourth mode. The fourth mode is intended to pre-heat and defog the vehicle cabin. The heat energy comes from the compressor 1a power source, the electric power electronics unit, the electric motor waste heat and the front end exterior heat exchanger 5 as an ambient air source.

[0106] The battery is not heated or cooled by the refrigerant. For example, the battery has reached a thermal state that does not require external heating or cooling.

[0107] The first pilot valve 19 is de-energized closed and the second pilot valve 18 is energized open. The first 3 / 2 way valve 14 is in Pa flow logic and the second 3 / 2 way valve 10 is in Ta flow logic. The first 2 / 2 way valve 16 is in flow area open state and the second 2 / 2 way valve 17 is in flow area open position.

[0108] Heat is extracted through the front end exterior heat exchanger 5 of the vehicle’s front end cooler module and then rejected to the vehicle cabin airflow through the condenser 2.

[0109] The first expansion valve 4 is in proportional control of refrigerant expansion as the front end exterior heat exchanger 5 is working in evaporative mode and the first 4 / 2 way valve 15 directs the high pressure refrigerant flow from the condenser 2 outlet upstream of the first expansion valve 4.

[0110] The evaporator 6 is working in evaporative mode to cool and remove moisture from the airflow to the vehicle cabin.

[0111] The fourth expansion valve 13 is in proportional control to extract heat from the electric power electronics unit. Depending on the heat extraction demand, the fourth expansion valve 13 can gradually transition to a closed state if no more cooling of the electric power electronics unit or electric motor is required.

[0112] The evaporator 6 is in heat extraction mode, so the second 4 / 2 way valve 3 first directs the high pressure refrigerant flow to the third expansion valve 12. The third expansion valve 12 is in proportional control state.

[0113] The battery cooler 7 is off, so the second expansion valve 11 is fully closed.

[0114] Referring to Fig. 10, the heat pump system is in the fifth mode. This fifth mode aims to pre-heat and defog the vehicle cabin. The thermal energy comes from the compressor 1a power source, power electronics unit and electric motor waste heat. The difference compared to the fourth mode is that the front end external heat exchanger 5 no longer absorbs heat from the environment, but rejects heat.

[0115] The battery is not heated or cooled by the refrigerant. For example, the battery has reached a thermal state that does not require external heating or cooling.

[0116] The first pilot valve 19 is de-energized closed, the second pilot valve 18 is de- energized closed. The first 3 / 2 way valve 14 and the second 3 / 2 way valve 10 are both in Pa flow logic. The first 2 / 2 way valve 16 is in flow area open state, while the second 2 / 2 way valve 17 is in flow area closed position.

[0117] Heat is rejected through the front end external heat exchanger 5, which is the front end cooler module of the vehicle. Since the front end external heat exchanger 5 is working in condensing mode, the first expansion valve 4 is in full open state, and the first 4 / 2 way valve 15 directs the high pressure refrigerant flow from the condenser 2 outlet first to the front end external heat exchanger 5.

[0118] The evaporator 6 is working in evaporating mode to cool and remove moisture from the airflow to the vehicle cabin.

[0119] The fourth expansion valve 13 is in proportional control to absorb heat from the power electronics unit. Depending on the heat absorption demand, the fourth expansion valve 13 can gradually turn to closed state if no more cooling of the power electronics unit or electric motor is required.

[0120] The evaporator 6 is in heat absorption mode, so the second 4 / 2 way valve 3 directs the high pressure refrigerant flow first to the third expansion valve 12. The third expansion valve 12 is in proportional control state.

[0121] The battery cooler 7 is closed, so the second expansion valve 11 is fully closed.

[0122] Referring to Fig. 11, the heat pump system is in the sixth mode. This sixth mode aims to cool the battery only. There is no heating or cooling of the vehicle cabin by the refrigerant.

[0123] The first pilot valve 19 is de-energized closed, the second pilot valve 18 is de- energized closed. The first 3 / 2 way valve 14 and the second 3 / 2 way valve 10 are both in Pa flow logic. The first 2 / 2 way valve 16 is in flow area open state, while the second 2 / 2 way valve 17 is in flow area closed position.

[0124] Heat is rejected through the front end external heat exchanger 5 which is the front end cooler module of the vehicle. Since the front end external heat exchanger 5 is working in condensing mode, the first expansion valve 4 is in full open state and the first 4 / 2 way valve 15 directs the high pressure refrigerant flow from the condenser 2 outlet first to the front end external heat exchanger 5.

[0125] The cabin airflow is not heated. The airflow over the condenser 2 is typically bypassed by a damper (not shown in the figure).

[0126] The fourth expansion valve 13 is in proportional control to absorb heat from the power electronics unit. Depending on the heat absorption demand, the fourth expansion valve 13 can gradually be turned to the closed state if no more cooling of the power electronics unit or electric motor is required.

[0127] The battery cooler 7 is in heat absorption mode, so the second 4 / 2 way valve 3 directs the high pressure refrigerant flow first to the second expansion valve 11. The second expansion valve 11 is in proportional control.

[0128] The evaporator 6 is closed, so the third expansion valve 12 is fully closed.

[0129] Referring to Fig. 12, the heat pump system is in the seventh mode. This seventh mode is intended to cool the battery and the cabin simultaneously.

[0130] The first pilot valve 19 is de-energized closed and the second pilot valve 18 is de-energized closed. The first 3 / 2 way valve 14 and the second 3 / 2 way valve 10 are both in Pa flow logic. The first 2 / 2 way valve 16 is in flow passage open state and the second 2 / 2 way valve 17 is in flow passage closed position.

[0131] Heat is rejected through the front end external heat exchanger 5 which is the front end cooler module of the vehicle. Since the front end external heat exchanger 5 is working in condensing mode, the first expansion valve 4 is in full open state and the first 4 / 2 way valve 15 directs the high pressure refrigerant flow from the condenser 2 outlet first to the front end external heat exchanger 5.

[0132] The cabin airflow is not heated. The airflow over the condenser 2 is typically bypassed by a damper (not shown in the figure).

[0133] The fourth expansion valve 13 is in proportional control to absorb heat from the power electronics unit. Depending on the heat absorption demand, the fourth expansion valve 13 can gradually be turned to the closed state if no more cooling of the power electronics unit or electric motor is required.

[0134] The evaporator 6 and the battery cooler 7 are both in heat absorption mode, so the second 4 / 2 way valve 3 directs the high pressure refrigerant flow first to the second expansion valve 11 and the third expansion valve. The second expansion valve 11 and the third expansion valve are in proportional control.

[0135] Referring to Fig. 13, the heat pump system is in an eighth mode. This eighth mode is intended for cooling of the vehicle cabin only. The battery is not heated or cooled by the refrigerant.

[0136] The first pilot valve 19 is de-energized closed and the second pilot valve 18 is de- energized closed. The first 3 / 2 way valve 14 and the second 3 / 2 way valve 10 are in Pa flow logic. The first 2 / 2 way valve 16 is in flow area open state and the second 2 / 2 way valve 17 is in flow area closed position.

[0137] Heat is rejected through the front end external heat exchanger 5 as a front end cooler module of the vehicle. Since the front end external heat exchanger 5 is working in condensing mode, the first expansion valve 4 is in full open state and the first 4 / 2 way valve 15 directs the high pressure refrigerant flow from the condenser 2 outlet first to the front end external heat exchanger 5.

[0138] The vehicle cabin airflow is not heated. The airflow over the condenser 2 is typically bypassed by a damper (not shown in the figure).

[0139] The fourth expansion valve 13 is in proportional control to absorb heat from the power electronics unit. Depending on the heat absorption demand, the fourth expansion valve 13 can gradually be turned to a closed state if no more cooling of the power electronics unit or electric motor is required.

[0140] The evaporator 6 is in heat absorption mode, so the second 4 / 2 way valve 3 directs the high pressure refrigerant flow first to the third expansion valve 12. The third expansion valve 12 is in proportional control state.

[0141] The battery cooler 7 is closed, so the second expansion valve 11 is fully closed.

[0142] Referring to Fig. 14, the heat pump system is in a ninth mode. This ninth mode is intended for pre-heating of the battery only. The vehicle cabin is not heated or cooled by the refrigerant.

[0143] The first pilot valve 19 and the second pilot valve 18 are both in energized open state. The first 3 / 2 way valve 14 and the second 3 / 2 way valve 10 are in Ta flow logic. The first 2 / 2 way valve 16 is in flow area closed state and the second 2 / 2 way valve 17 is in flow area open position.

[0144] Heat is extracted through the front end external heat exchanger 5 as a front end cooler module of the vehicle.

[0145] The vehicle cabin airflow is not heated. The airflow over the condenser 2 is typically bypassed by a damper (not shown in the figure).

[0146] As the front end external heat exchanger 5 is working in evaporating mode, the first expansion valve 4 is in proportional control of refrigerant expansion and the first 4 / 2 way valve 15 directs the high pressure refrigerant flow from the condenser 2 outlet upstream of the first expansion valve 4.

[0147] The fourth expansion valve 13 is in proportional control to extract heat from the power electronics unit and the electric motor.

[0148] The battery cooler 7 is in heat rejection mode, so the second 4 / 2 way valve 3 first directs the high pressure refrigerant flow to the battery cooler 7. The second expansion valve 11 is in full open state.

[0149] The evaporator 6 is shut off, so the third expansion valve 12 is fully closed. The evaporator 6 does not heat or cool the cabin airflow.

[0150] Referring to Fig. 15, the heat pump system is in the tenth mode. This tenth mode aims to cool the battery while de-fogging / warming the cabin.

[0151] The first pilot valve 19 is de-energized closed and the second pilot valve 18 is de- energized closed. The first 3 / 2 way valve 14 and the second 3 / 2 way valve 10 are both in Pa flow logic. The first 2 / 2 way valve 16 is in flow passage open state and the second 2 / 2 way valve 17 is in flow passage closed position.

[0152] Heat is rejected through the front end external heat exchanger 5 which is the front end cooler module of the vehicle. As the front end external heat exchanger 5 is working in condensing mode, the first expansion valve 4 is in full open state. The first 4 / 2 way valve 15 directs the high pressure refrigerant flow from the condenser 2 outlet first to the front end external heat exchanger 5.

[0153] The cabin airflow is still being warmed up, i.e. there is airflow over the condenser 2. The airflow over the condenser 2 is typically bypassed by a damper (not shown in the figures).

[0154] The fourth expansion valve 13 is in proportional control to extract heat from the power electronics unit. Depending on the heat extraction demand, the fourth expansion valve 13 can gradually be turned to closed state if no more cooling of the power electronics unit or electric motor is required.

[0155] The evaporator 6 and the battery cooler 7 are both in heat extraction mode, so the second 4 / 2 way valve 3 first directs the high pressure refrigerant flow to the second expansion valve 11 and the third expansion valve 12. The second expansion valve 11 and the third expansion valve 12 are in proportional control.

[0156] Referring to Fig. 16, the heat pump system is in the eleventh mode. This eleventh mode aims to cool the battery and at the same time heat (not de-fog) the cabin.

[0157] The first pilot valve 19 is de-energized closed, the second pilot valve 18 is de- energized closed. The first 3 / 2 way valve 14 and the second 3 / 2 way valve 10 are both in Pa flow logic. The first 2 / 2 way valve 16 is in flow area open state, while the second 2 / 2 way valve 17 is in flow area closed position.

[0158] Heat is rejected through the front end external heat exchanger 5 as a front end cooler module of the vehicle. Since the front end external heat exchanger 5 is working in condensing mode, the first expansion valve 4 is in full open state. The first 4 / 2 way valve 15 directs the high pressure refrigerant flow from the condenser 2 outlet first to the front end external heat exchanger 5.

[0159] The cabin airflow is being heated, i.e. there is airflow over the condenser 2.

[0160] The fourth expansion valve 13 is in proportional control to absorb heat from the power electronics unit. Depending on the heat absorption demand, the fourth expansion valve 13 can gradually be turned to a closed state if no more cooling of the power electronics unit or electric motor is needed.

[0161] Only the battery cooler 7 is in heat absorption mode, so the second 4 / 2 way valve 3 directs the high pressure refrigerant flow first to the second expansion valve 11. The second expansion valve 11 is in proportional control state.

[0162] The evaporator 6 is closed, so the third expansion valve 12 is fully closed. The evaporator 6 unit does not heat or cool the cabin airflow.

[0163] Referring to Fig. 17, the twelfth mode of the heat pump system is shown. This twelfth mode is intended for front end external heat exchanger 5 defrosting, while de-icing and heating (de-fogging) of the cabin. Optionally, the battery is not heated.

[0164] The first pilot valve 19 is in energized open state, the second pilot valve 18 is in de-energized closed state. The first 3 / 2 way valve 14 is in Ta flow logic, the second 3 / 2 way valve 10 is in Pa flow logic. The first 2 / 2 way valve 16 is in flow area closed position, while the second 2 / 2 way valve 17 is in flow area closed position.

[0165] Heat is rejected through the front end external heat exchanger 5 as a front end cooler module of the vehicle. Since the front end external heat exchanger 5 is working in condensing mode, the first expansion valve 4 is in full open state, the first 4 / 2 way valve 15 directs the high pressure refrigerant flow from the condenser 2 outlet first to the front end external heat exchanger 5.

[0166] The cabin airflow is being heated, i.e. there is airflow over the condenser 2.

[0167] The fourth expansion valve 13 is in proportional control to absorb heat from the power electronics unit. Depending on the heat absorption demand, the fourth expansion valve 13 can gradually go to a closed state if no more cooling of the power electronics unit or the electric motor is required.

[0168] The third expansion valve 12 is in full open state. The evaporator 6 is in heat rejection mode, so the second 4 / 2-way valve 3 first directs the high pressure refrigerant flow to 6.

[0169] The battery cooler 7 is off, so the second expansion valve 11 is fully closed.

[0170] Figs. 18A and 18B are structural schematic diagrams of a heat pump system according to a comparative example. In order to directly compare the heat pump system of the embodiments of the present application with a heat pump system having only stop valves, Fig. 18A shows the same heat pump system with stop valves and small diameter expansion valves (not recommended for full closed operation).

[0171] As shown in Fig. 18A, two sets of 4 stop valves are used for reverse flow (instead of two 4 / 2-way valves), two sets of 3 stop valves are used as branch switching (instead of two center valves), 4 small expansion valves and 3 stop valves (fully open for battery cooler 7, evaporator 6 and front end external heat exchanger 5 in heat rejection mode; fully closed in heat absorption / expansion mode) instead of 4 large diameter expansion valves. In summary, 4 small diameter expansion valves and 8+6+3 = 17 stop valves. If all reverse flow operations are omitted due to lower heat exchanger efficiency, the number of stop valves will be reduced to 6+3 = 9, as shown in Fig. 18B.

[0172] As can be seen from Figs. 18A and 18B, the heat pump system of the present application has a reduced total number of valves due to the combination of stop valves into the form of 2-way, 3-way and 4-way valves. In addition, the total number of valves can be further reduced due to the adoption of large diameter expansion valves instead of small diameter expansion valves.

[0173] The present embodiments also provide a vehicle comprising the heat pump system. It can be understood that, since the vehicle contains the heat pump system for a vehicle provided by any of the foregoing embodiments, the heat pump system for a vehicle can also achieve the technical effects achieved in any of the foregoing embodiments in the vehicle, and therefore the present embodiments will not be described in more detail.

Claims

1. A heat pump system for a vehicle, comprising: a compressor (1a) that compresses refrigerant; a refrigerant circuit that forms a closed loop flow path of refrigerant; a plurality of switching valves including at least one of a 2 / 2-way valve, a 3 / 2-way valve, and a 4 / 2-way valve, wherein the 2 / 2-way valve is configured to be controlled to shut off or turn on the flow path, the 3 / 2-way valve is configured to be controlled to switch the flow path, and the 4 / 2-way valve is configured to be controlled to reverse heat exchange; and a first pilot valve (19) that controls at least two of the plurality of switching valves at the same time. 2.The heat pump system according to claim 1, wherein the first pilot valve (19) is a 3 / 2-way valve having three ports, a first port connected to a discharge side of the compressor (1a), a second port connected to a suction side of the compressor (1a), and a third port leading to a pilot passage of the at least two switching valves. 3.The heat pump system according to claim 1, further comprising a plurality of heat exchange devices including a first heat exchange device, wherein the plurality of switching valves include a first 4 / 2-way valve (15) having four interfaces, a first interface (15P) connected to a discharge side of the compressor (1a), and a second interface (15T) connected to a suction side of the compressor (1a), the first heat exchange device is connected to a third interface (15a) and a fourth interface (15b) and absorbs or releases heat according to a circulating direction of the refrigerant. 4.The heat pump system according to claim 3, wherein the plurality of heat exchange devices further include a second heat exchange device, and the plurality of switching valves further include a first 2 / 2-way valve (16) and a first 3 / 2-way valve (14), the first 2 / 2-way valve (16) is located on a flow path between the second interface (15T) of the first 4 / 2-way valve (15) and the suction side of the compressor (1a), the first 3 / 2-way valve (14) has three ports, a first port (14P) connected to the discharge side of the compressor (1a), a second port (14T) connected to the second interface (15T) of the first 4 / 2-way valve (15), and a third port (14a) connected to the suction side of the compressor (1a), the second heat exchange device is located on a flow path between the third port (14a) and the suction side, the first pilot valve (19) controls the first 2 / 2-way valve (16) and the first 3 / 2-way valve (14) so as to switch series and parallel connection between the first heat exchange device and the second heat exchange device. 5.The heat pump system according to claim 4, further comprising a second pilot valve (18), the plurality of heat exchange devices further include a third heat exchange device, and the plurality of switching valves further include a second 2 / 2-way valve (17), a second 3 / 2-way valve (10), and a second 4 / 2-way valve (3), the second 4 / 2-way valve (3) has four ports, a first port (3P) connected to a discharge side of the compressor (1a), and a second port (3T) connected to a suction side of the compressor (1a), ​ The second 2 / 2-way valve (17) is located on a flow path between the second opening (3T) and a suction end of the compressor (1a), The third heat exchange device is connected to a third opening (3a) and a fourth opening (3b) respectively, and absorbs or releases heat according to a circulating direction of the refrigerant, The second 3 / 2-way valve (10) has three flow ports, a first flow port (10T) connected to a first opening (3P) of the second 4 / 2-way valve (3), a second flow port (10P) connected to a second opening (3T) of the second 4 / 2-way valve (3), and a third flow port (10a) connected to a suction end of the compressor (1a), The second pilot valve (18) controls the second 2 / 2-way valve (17) and the second 3 / 2-way valve (10), so as to switch the series-parallel connection between the first heat exchange device and the third heat exchange device.

6. The heat pump system according to claim 5, wherein The first pilot valve (19) simultaneously controls the first 2 / 2-way valve (16), the first 3 / 2-way valve (14) and the first 4 / 2-way valve (15), and the second pilot valve (18) simultaneously controls the second 2 / 2-way valve (17), the second 3 / 2-way valve (10) and the second 4 / 2-way valve (3).

7. The heat pump system according to claim 6, wherein The second pilot valve (18) is a 3 / 2-way valve having three valve ports, a first valve port connected to a discharge end of the compressor (1a), a second valve port connected to a suction end of the compressor (1a), and a third valve port leading to a pilot passage of the second 2 / 2-way valve (17), the second 3 / 2-way valve (10) and the second 4 / 2-way valve (3).

8. The heat pump system according to claim 5, wherein The third heat exchange device is a front-end external heat exchanger (5).

9. The heat pump system according to claim 3, wherein The first heat exchange device includes a battery cooler (7) and an evaporator (6) connected in parallel.

10. The heat pump system according to claim 4, wherein The second heat exchange device includes a power electronic unit cooler (8) and a motor cooler (9) connected in series.

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