Vehicle air conditioning device

Abstract

In a case where a hot-gas heating operation mode is continuously operated, control of a refrigerant circuit that enables efficient consumption of energy of a compressor (rotation number control of the compressor) is executed. The vehicle air-conditioning device includes a refrigerant circuit that depressurizes refrigerant discharged from a compressor and returns the refrigerant to the compressor, a vehicle cabin air-conditioning device that temperature-adjusts air blown into a vehicle cabin through an indoor heat exchanger of the refrigerant circuit, and a control device that controls the refrigerant circuit and the vehicle cabin air-conditioning device on the basis of input information. The refrigerant circuit includes a refrigerant flow path that has a hot-gas bypass path that depressurizes a portion of refrigerant compressed in the compressor without passing through the indoor heat exchanger and flows the refrigerant to a suction side of the compressor, and enables the hot-gas heating operation mode. The control device, in the hot-gas heating operation mode in which the portion of the refrigerant compressed in the compressor flows to the indoor heat exchanger and the remaining refrigerant flows to the hot-gas bypass path, executes control of variably setting a target pressure of the refrigerant circuit in a range in which a heating requirement can be maintained, in consideration of a necessary capacity obtained on the basis of a set heating requirement and a vehicle requirement.

Description

Technical Field

[0001] This invention relates to an air conditioning device for vehicles. Background Technology

[0002] In electric vehicles (EVs) without a combustion system or other heat source, and in vehicles with low-heat combustion systems, air conditioning systems that use heat pumps as the heat source are generally employed. During normal heating operation, these systems absorb heat from the outside air in the outdoor heat exchanger (acting as a heat absorber) and heat the air delivered to the passenger compartment in the interior air conditioning unit's heat exchanger (acting as a radiator). Therefore, during normal heating operation, when the outside air temperature becomes extremely low, it becomes difficult to absorb heat from the outside air, resulting in reduced heating capacity.

[0003] In contrast, the hot gas heating operation mode achieves heating operation in extremely low-temperature external gas environments where heat absorption is difficult to achieve in the outdoor heat exchanger section. This is achieved by circulating the high-temperature, high-pressure refrigerant discharged from the heat pump compressor to the heat exchange section of the vehicle's air conditioning unit, depressurizing it without passing through the outdoor heat exchanger section, and then drawing it into the compressor. The hot gas heating operation mode involves setting a bypass refrigerant path (hot gas bypass path) in the refrigerant circuit, where a portion of the high-temperature, high-pressure refrigerant discharged from the compressor is depressurized without passing through the heat exchanger of the vehicle's air conditioning unit and returned to the compressor. A portion of the refrigerant compressed in the compressor flows to the heat exchange section of the vehicle's air conditioning unit, while the remaining refrigerant flows to the hot gas bypass path. This allows for regulation of the amount of heat input and dissipation during operation (see Patent Document 1 below).

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2023-46604 Summary of the Invention

[0007] The technical problem that the invention aims to solve

[0008] Previously, in hot gas heating mode, in order to perform continuous operation to meet various requirements, the compressor in the refrigerant circuit was rotated at a set speed close to its capacity limit and kept running so that the energy consumed by the compressor (heat input) was greater than the amount of heat dissipation required by various requirements. However, in the case of continuous hot gas heating mode for a long time, the remaining power of the battery will decrease due to the energy consumed by the compressor, thus resulting in a shortened driving range of the electric vehicle.

[0009] The present invention was made in view of the above circumstances. That is, the object of the present invention is to perform control of the refrigerant circuit (compressor speed control) that enables the compressor to consume energy efficiently when the hot gas heating operation mode is continuously operated.

[0010] Technical solutions adopted to solve technical problems

[0011] To solve the above-mentioned technical problems, the present invention includes the following structure.

[0012] A vehicle air conditioning system includes: a refrigerant circuit that depressurizes refrigerant discharged from a compressor and returns it to the compressor; an in-vehicle air conditioning unit that regulates the temperature of air supplied to the vehicle interior via an in-vehicle heat exchange section of the refrigerant circuit; and a control device that controls the refrigerant circuit and the in-vehicle air conditioning unit based on input information. The refrigerant circuit includes a refrigerant flow path that depressurizes a portion of the refrigerant compressed in the compressor without passing through the in-vehicle heat exchange section and allows it to flow to the suction side of the compressor via a hot gas bypass path. The refrigerant flow path is capable of operating in a hot gas heating mode. In this hot gas heating mode, where a portion of the refrigerant compressed in the compressor flows to the in-vehicle heat exchange section and the remaining refrigerant flows to the hot gas bypass path, the control device, considering the necessary capacity determined based on pre-set heating requirements and vehicle requirements, variably sets the target pressure of the refrigerant circuit within a range sufficient to maintain the heating requirements.

[0013] Invention Effects

[0014] In an automotive air conditioning system with the above features, when the hot air heating mode is continuously operated, the control of the refrigerant circuit (compressor speed control) that enables the compressor to consume energy efficiently can be performed. Attached Figure Description

[0015] Figure 1 This is an explanatory diagram showing a structural example of an automotive air conditioning device according to an embodiment of the present invention.

[0016] Figure 2 This is an explanatory diagram showing the control device of a vehicle air conditioning system.

[0017] Figure 3 This is an explanatory diagram showing the hardware structure of the control device for an air conditioning system installed in an electric vehicle (EV).

[0018] Figure 4 This is an explanatory diagram illustrating the operation of the refrigerant circuit in the hot air heating mode of an automotive air conditioning system according to an embodiment of the present invention.

[0019] Figure 5 This is a diagram illustrating the preprocessing steps performed relative to the mode selection process by the control device.

[0020] Figure 6 This is a flowchart illustrating the mode selection process performed by the control device.

[0021] Figure 7 This is a block diagram of the control device for variable PSO control after transitioning to the second selection mode.

[0022] Figure 8 This is an illustration diagram showing an example of a mapping diagram that shows the range of target values ​​for the refrigerant pressure PCO obtained from the target blow-out temperature TAO.

[0023] Figure 9 This is an explanatory diagram showing the method for determining the operating state of a target.

[0024] Figure 10 This is an explanatory diagram showing the relationship (inverse linear relationship) between PCO and PSO under the premise of constant target blowing temperature. Detailed Implementation

[0025] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same symbols in different figures denote parts with the same function, and repeated descriptions in each figure are omitted as appropriate.

[0026] [Structure of refrigerant circuits, etc., in automotive air conditioning systems]

[0027] exist Figure 1 The diagram shows a structural example of an automotive air conditioning device 1 according to an embodiment of the present invention. The structural example shown here is an example and is not particularly limited to a specific structure.

[0028] The vehicle air conditioning unit 1 includes a refrigerant circuit 10 and an in-vehicle air conditioning unit 20. The refrigerant circuit 10 has a refrigerant flow path that depressurizes the refrigerant discharged from the compressor 2 and returns it to the compressor 2. Along the refrigerant flow path are the compressor 2, indoor heat exchange units 21 and 22 located inside the in-vehicle air conditioning unit 20, and an outdoor heat exchange unit 11 located outside the vehicle. The indoor heat exchange units 21 and 22 are provided for heat exchange between the air circulating inside the air conditioning unit 20 and the refrigerant within the vehicle interior, while the outdoor heat exchange unit 11 is provided for heat exchange between the outside air and the refrigerant outside the vehicle. For example, the indoor heat exchange unit 21 is used to heat the air, and the indoor heat exchange unit 22 is used to cool the air. A refrigerant pressure sensor 44B is provided downstream of the indoor heat exchange unit 21 in the refrigerant flow path, which detects the outlet refrigerant pressure (high-pressure side refrigerant pressure) Pci flowing out of the indoor heat exchange unit 21.

[0029] Compressor 2 compresses the refrigerant and circulates it within refrigerant circuit 10. The refrigerant compressed in compressor 2 is selectively reduced to the desired pressure via, for example, a first pressure reducing section V1, a second pressure reducing section V2, a third pressure reducing section V3, and a fourth pressure reducing section V4, which are expansion valves, in a suitably selected refrigerant flow path. Flow path switching valves 12 and 13 for switching the refrigerant flow path and check valves 14 and 15 for restricting the direction of refrigerant flow are provided in refrigerant circuit 10. A storage tank 16 is provided upstream of compressor 2 in refrigerant circuit 10, which recovers liquid refrigerant and performs gas-liquid separation of the refrigerant. A refrigerant pressure sensor 44A is provided between storage tank 16 and compressor 2, which detects the suction refrigerant pressure (low-pressure side refrigerant pressure) Ps drawn into compressor 2.

[0030] As described above, the vehicle interior air conditioning unit 20 includes indoor and outdoor heat exchange sections 21 and 22. Air drawn in from the indoor or outdoor environment by the blower 23 is conditioned by passing through the indoor heat exchange sections 21 and 22 and then blown into the interior. An air baffle 24 is provided in the vehicle interior air conditioning unit 20. Figure 1 When the air baffle 24 shown is fully open, the air introduced by the blower 23 passes through the indoor heat exchange sections 21 and 22 and is blown out into the room.

[0031] Furthermore, when the air baffle 24 is fully closed, the inflow side of the indoor heat exchange section 21 is blocked, and the air introduced by the blower 23 passes through the indoor heat exchange section 22 only and is blown into the room. Another air baffle 25 provided in the vehicle interior air conditioning unit 20 switches the air introduced into the blower 23 between the indoor and outdoor environments. The air baffle 25 can selectively close the air inlet 25A connected to the outside and the air inlet 25B connected to the inside, and draw in air from either side. In addition, by setting the air baffle 25 to an intermediate position, air can be drawn in from both the air inlet 25A and the air inlet 25B.

[0032] Furthermore, while the outdoor heat exchange section 11 and indoor heat exchange sections 21 and 22 described above exemplify direct heat exchange between the refrigerant and air, the refrigerant and air can also exchange heat indirectly via a heat carrier that has exchanged heat with the refrigerant. That is, a structure can be used where the refrigerant absorbs heat from the air via a heat carrier or where the refrigerant releases heat into the air via a heat carrier.

[0033] like Figure 1As shown, the vehicle air conditioning unit 1 includes a heat transfer circuit 30 for temperature regulation of on-board equipment. The heat transfer circuit 30 circulates the heat transfer fluid via a circulation pump 31, heats the heat transfer fluid via a heater 32 (ECH: Electric Coolant Heater), or recovers waste heat from on-board equipment (temperature-regulated objects) such as batteries via a temperature-regulated object heat exchange section 33. Furthermore, in both the refrigerant circuit 10 and the heat transfer circuit 30, a refrigerant heat transfer heat exchange section 34, which performs heat exchange between the refrigerant and the heat transfer fluid in the flow path 34A for refrigerant flow and the flow path 34B for heat transfer fluid flow, is configured as a heat exchange section for temperature regulation of the on-board equipment. The aforementioned heat transfer circuit 30 is configured as needed.

[0034] [Control Device]

[0035] Vehicle air conditioning unit 1 includes Figure 2 The control device (air conditioning ECU) 100 is shown. Based on various input information J, including user settings and information from the vehicle, and detection information from the sensor unit 40, the control device 100 controls the refrigerant circuit 10 and the in-vehicle air conditioning unit 20 described above, and controls the heat transfer circuit 30 as needed. Furthermore, the control device 100 is connected to a database DB used when executing the control mode described later. Additionally, the database DB does not necessarily need to exist internally in the vehicle air conditioning unit 1; it can be connected to an externally existing database DB using the vehicle's communication functions.

[0036] The sensor unit 40 that inputs the detection signal to the control device 100 includes, for example, an external gas sensor 41, a compressor current sensor 42, a refrigerant temperature sensor 43, a refrigerant pressure sensor 44, and an air supply temperature sensor 45. The external gas sensor 41 detects the external gas state, such as external gas temperature and external gas humidity. The compressor current sensor 42 is used to detect the power consumption (energy consumption) of the compressor 2. The refrigerant temperature sensor 43 and the refrigerant pressure sensor 44 detect the state of the refrigerant. The air supply temperature sensor 45 detects the air supply temperature of the vehicle interior air conditioning unit 20.

[0037] In particular, the refrigerant pressure sensor 44 includes a refrigerant pressure sensor 44A and a refrigerant pressure sensor 44B. The refrigerant pressure sensor 44A detects the suction refrigerant pressure (low-pressure side refrigerant pressure) Ps drawn into the compressor 2, and the refrigerant pressure sensor 44B detects the outlet refrigerant pressure (high-pressure side refrigerant pressure) Pci of the indoor heat exchange section 21. These sensors are just one example of various sensors installed in the sensor section 40 to detect information required for various controls of the control device 100.

[0038] The controlled objects of the control device 100 are, in the refrigerant circuit 10, compressor 2, first pressure reducing unit V1, second pressure reducing unit V2, third pressure reducing unit V3, fourth pressure reducing unit V4, flow path switching valves 12 and 13, etc.; in the vehicle interior air conditioning unit 20, blower 23, air baffles 24 and 25, etc.; and in the heat carrier circuit 30, circulation pump 31, etc. In the vehicle air conditioning unit 1, the control device 100 can switch between an external gas heat absorption and heating operation mode and a hot gas heating operation mode. In the external gas heat absorption and heating operation mode, heat is absorbed from the external gas through the outdoor heat exchange unit 11. In the hot gas heating operation mode, heat is not absorbed from the external gas through the outdoor heat exchange unit 11, but the high-temperature refrigerant compressed by the compressor 2 is dissipated through the indoor heat exchange unit 21 to heat the vehicle interior.

[0039] [Structure of the control unit in an electric vehicle (EV)]

[0040] The control device (air conditioning ECU) 100 included in the vehicle air conditioning system 1, such as Figure 3 The diagram shows an ECU configured to be connected via an in-vehicle network L to various ECUs (Electronic Control Units) for controlling an electric vehicle (EV). The control device 100 includes a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, a RAM (Random Access Memory) 103, an input / output I / F (Interface) 104, an in-vehicle communication I / F (Interface) 105, etc., and the various hardware components are interconnected via a bus 106.

[0041] CPU 101 executes various programs stored in ROM 102 to control the control device 100. ROM 102 is non-volatile memory. For example, ROM 102 stores programs executed by CPU 101, data required by CPU 101 to execute programs, etc. RAM 103 is a main storage device such as DRAM (Dynamic Random Access Memory) or SRAM (Static Random Access Memory).

[0042] For example, RAM 103 functions as a working area used when the CPU 101 executes a program. Input / output I / F 104 connects to various sensors and displays installed in the EV to input data to the CPU 101 and outputs data processed by the CPU 101. In-vehicle communication I / F 105 connects to the vehicle network L to control data transmission and reception between other ECUs installed in the EV.

[0043] The control device 100 receives data related to the surrounding environment or the operating status of the EV via the input / output I / F 104 and the in-vehicle communication I / F 105, and then executes the control of the aforementioned vehicle air conditioning device 1 through the program executed by the CPU 101.

[0044] The EV is equipped with a battery B. The battery B is charged by connecting the charger plug PS to the battery plug BP, and the vehicle air conditioning unit 1 is powered by the battery B. The state of the battery socket BP being connected to the plug PS is sent to the control device 100 via the vehicle network L as a charger connection signal.

[0045] [External gas heat absorption and heating operation mode]

[0046] The operation of refrigerant circuit 10 in external gas heat absorption and heating mode Figure 1 In the refrigerant circuit 10 shown, the second pressure reducing unit V2, the third pressure reducing unit V3, the fourth pressure reducing unit V4, and the flow path switching valve 12 are all closed. On the other hand, the flow path switching valve 13 is open, and the first pressure reducing unit V1 is open.

[0047] In the external gas heat absorption and heating operation mode, the high-temperature, high-pressure refrigerant discharged from the compressor 2 passes through the indoor heat exchange section 21 within the vehicle interior air conditioning unit 20 and is depressurized in the first pressure reducing section V1. The low-pressure refrigerant then passes through the outdoor heat exchange section 11 and returns to the compressor 2 via the flow path switching valve 13, check valve 14, and storage tank 16. At this time, the following cycle occurs: the high-pressure refrigerant flowing from the compressor 2 condenses and dissipates heat in the indoor heat exchange section 21, and is depressurized by the first pressure reducing section V1 to become low-pressure refrigerant. It then absorbs heat and evaporates in the outdoor heat exchange section 11 and returns to the compressor 2. Furthermore, in the vehicle interior control device 20, the air introduced to the blower 23 is heated by heat dissipation in the indoor heat exchange section 21 and blown into the vehicle interior.

[0048] [Refrigerant circuit operation in hot gas heating mode]

[0049] In the hot air heating operation mode, the refrigerant does not absorb heat in the outdoor heat exchange section 11. Instead, part or all of the refrigerant compressed by the compressor 2 dissipates heat through the indoor heat exchange section 21 to heat the vehicle interior. Figure 4 The operation of the refrigerant circuit 10 in the hot gas heating mode is explained below. The thick black lines in the refrigerant circuit 10 shown in the diagram indicate the refrigerant flow path for high-pressure refrigerant, while the blank lines indicate the refrigerant flow path for refrigerant after pressure reduction. Furthermore, the dashed lines in the refrigerant circuit 10 indicate refrigerant flow paths where refrigerant is not flowing, and the dashed lines in the heat carrier circuit 30 indicate the cessation of heat carrier flow.

[0050] exist Figure 4 In the refrigerant circuit 10, a portion of the high-temperature, high-pressure refrigerant discharged from compressor 2 passes through indoor heat exchange section 21 and flow path switching valve 12, and is reduced in pressure in third pressure reducing section V3 to become low-pressure refrigerant. It then passes through refrigerant heat carrier heat exchange section 34, undergoes gas-liquid separation in storage tank 16, and returns to compressor 2. At this time, in refrigerant circuit 10, first pressure reducing section V1 is fully closed to prevent refrigerant from flowing to outdoor heat exchange section 11. Furthermore, fourth pressure reducing section V4 is fully closed to prevent refrigerant from flowing to indoor heat exchange section 22.

[0051] The refrigerant circuit 10 includes a refrigerant flow path that allows at least a portion of the refrigerant compressed in the compressor 2 to be depressurized and returned to the compressor 2 via a hot gas bypass path 10V without passing through the indoor heat exchange section 21 and the outdoor heat exchange section 11. This refrigerant flow path is also capable of operating in a hot gas heating mode. In the hot gas bypass path 10V, a portion of the high-temperature, high-pressure refrigerant branches off at a bifurcation point P1 immediately downstream of the compressor 2 and is depressurized via a second depressurization section V2. It then merges with low-pressure refrigerant depressurized via a third depressurization section V3 at a confluence point P2 immediately upstream of the storage tank 16.

[0052] By setting up the hot gas bypass path 10V as described above, in the hot gas heating operation mode, the gaseous refrigerant passing through the hot gas bypass path 10V can mix with the liquid refrigerant condensed by heat dissipation through the indoor heat exchanger 21 to form a rich gas before returning to the compressor 2. Furthermore, by increasing the refrigerant flow rate in the hot gas bypass path 10V, the heat dissipation through the indoor heat exchanger 21 can be suppressed. By adjusting the refrigerant flow rate in the hot gas bypass path 10V through the opening and closing of the second pressure reducing unit V2, a balance can be maintained between the heat dissipation of the refrigerant circuit 10 and the heat input to the compressor 2. In other words, the second pressure reducing unit V2 functions as a flow regulating unit that adjusts the flow rate of the refrigerant flowing through the hot gas bypass path 10V.

[0053] In the hot air heating operation mode, the refrigerant flows through the indoor heat exchange section 21 and is depressurized in the third pressurization section V3. Therefore, the upstream side is high-pressure refrigerant, and the downstream side is low-pressure refrigerant. At this time, it is important that no heat exchange occurs in the refrigerant heat carrier heat exchange section 34 in the low-pressure side flow path in order to maintain the heating capacity. In addition, in the vehicle interior control device 20, the air introduced to the blower 23 is heated by heat dissipation in the indoor heat exchange section 21 and blown into the vehicle interior.

[0054] [Control of hot gas heating operation mode]

[0055] <Mode Selection Processing>

[0056] In hot air heating operation mode, control is performed by selecting a first selection mode (fixed target pressure mode) and a second selection mode (variable target pressure mode) based on the operating status of the vehicle air conditioning unit 1, the heating requirements set by the user, and the requirements from the vehicle. The first selection mode (fixed target pressure mode) is a heating performance priority mode used to maximize heating performance. It requires the maximum speed to continuously drive the compressor 2 of the refrigerant circuit 10, sets the target pressure of the refrigerant circuit 10 (e.g., the target value PSO of the low-pressure side refrigerant pressure) to a fixed value, and controls the system so that the measured pressure is close to the target pressure.

[0057] In contrast, the second selection mode (variable target pressure mode) prioritizes requirements such as improving COP (Coefficient of Performance). It allows the compressor 2 of refrigerant circuit 10 to operate at speeds not limited to its maximum speed. The target pressure of refrigerant circuit 10 (e.g., the target value PSO of the low-pressure side refrigerant pressure) is set to be variable according to requirements, and control is performed with the measured pressure close to the target pressure. In this second selection mode, energy consumption of refrigerant circuit 10 is controlled efficiently while ensuring the establishment of the hot gas heating operation mode (heat input exceeding heat dissipation).

[0058] In order to execute the mode selection of the first selection mode and the second selection mode, execute Figure 5 The process is illustrated below. Here, when the start (“START”) process is initiated, a first preprocessing step S1, a second preprocessing step S2, and a third preprocessing step S3 are performed to calculate the necessary capacity TGQ obtained based on the heating requirements set by the user and the requirements from the vehicle (vehicle requirements). The rotational speed limit of compressor 2 generated based on the vehicle requirements is also considered, and a mode selection process S4 is performed taking into account the calculated necessary capacity TGQ. This series of processes from the start (“START”) to the end (“END”) is repeated at predetermined time intervals after the start of the hot gas heating operation mode. The necessary capacity TGQ calculated here is the energy (J / s) required per unit time to meet the requirements described above.

[0059] exist Figure 5 In the first preprocessing step S1, the target heating capacity is obtained, for example, based on the user-defined heating requirements (set temperature and set airflow). The second preprocessing step S2, for example, is obtained based on input information from the vehicle to determine the required temperature regulation capacity of the on-board equipment (the object to be regulated). Specifically, the target temperature regulation capacity is inferred based on the target temperature of the object to be regulated. At this time, based on the requirements from the vehicle performing the temperature regulation of the on-board equipment, the... Figure 4 The heat transfer circuit 30 shown is set to the working state. The third preprocessing S3, for example, uses information from the vehicle to determine the vehicle's operating mode, such as the COP-enhanced operating mode (so-called eco-friendly driving mode) or the quiet driving mode (noise-suppressing operating mode), to obtain the compressor 2's speed limit requirements according to the operating mode.

[0060] Mode selection processing S4, such as Figure 6As shown, when the "START" process is initiated, a judgment process S10 for selecting a mode is performed. In the first judgment process S10A, it is determined whether the hot gas heating operation mode has just been started, and in the second judgment process S10B, it is determined whether there is a surplus of the necessary capacity TGQ obtained in the first preprocessing S1 and the second preprocessing S2 described above.

[0061] Here, the first judgment process S10A, for example, judges whether the time t measured since the start of the hot gas heating operation mode exceeds the set time t0. If it does not exceed the set time t0, it is judged that the hot gas heating operation mode has just been started (S10A: Yes). If it exceeds the set time t0, it is judged that the hot gas heating operation mode has not just been started (S10A: No). The set time t0 here can be set to a range that corresponds to the requirements.

[0062] The second judgment process S10B, for example, if the condition that the difference between the necessary capacity TGQ and the actual heating capacity Qhp is small or the necessary capacity TGQ itself is small (TGQ-Qhp<α or TGQ<β; α and β are different set values) continues, it is judged that there is a surplus (S10B: Yes). If the above conditions are not met, it is judged that there is no surplus (S10B: No).

[0063] In the judgment process S10, if the first judgment process S10A determines that the hot gas heating operation mode has just been started (S10A: Yes), the transfer process S11 to the first selection mode is executed. If the first judgment process S10A determines that the hot gas heating operation mode has not just been started (S10A: No), and the second judgment process S10B determines that there is no surplus (S10B: No), the transfer process S11 to the first selection mode is executed.

[0064] Furthermore, in the judgment process S10, if it is determined in the first judgment process S10A that the hot gas heating operation mode has not just been started (S10A: No), and in the second judgment process S10B that there is a surplus (S10B: Yes), the transfer process S20 to the second selection mode is executed.

[0065] After the transfer process S11 that transitions to the first selection mode, the speed limit requirement of compressor 2 obtained in the third preprocessing S3 described above is confirmed, and compressor 2 is driven at the maximum speed taking into account its speed limit requirement, while the fixed PSO control S12 described later is performed. Furthermore, after the transfer process S20 that transitions to the second selection mode, the variable PSO control S21 described later is performed.

[0066] <Fixed PSO control after switching to the first selection mode>

[0067] In the fixed PSO control (S12) after switching to the first selection mode, the control device 100 controls the refrigerant circuit 10 in such a way that the compressor 2 is continuously driven at the maximum speed considering the speed limit requirements mentioned above, while the high-pressure side refrigerant pressure of the refrigerant circuit 10 (the outlet refrigerant pressure Pci of the indoor heat exchange section 21, the discharge refrigerant pressure of the compressor 2, etc.) becomes the target value PCO. At this time, the second pressure reducing section V2 installed on the hot gas valve 10V is controlled so that the measured value Ps of the low-pressure side refrigerant pressure of the refrigerant circuit 10 (the suction refrigerant pressure Ps of the compressor 2, etc.) is close to the target value PSO, which is a fixed value, and the air volume of the blower 23 is controlled so that the actual heating capacity Qhp of the vehicle air conditioning unit 1 is the necessary capacity TGQ.

[0068] <Variable PSO control after switching to the second selection mode>

[0069] In the variable PSO control (S21) after switching to the second selection mode, the target operating state of the refrigerant circuit 10, obtained based on the user-set heating capacity and vehicle requirements, is determined and controlled in a manner that the measured value is close to the target operating state. The target operating state can be specified by the target pressure of the refrigerant circuit 10 (the target value of the high-pressure side refrigerant pressure PCO and the target value of the low-pressure side refrigerant pressure PSO), and is therefore expressed as follows (PCO, PSO).

[0070] To determine the target operating states (PCO, PSO) of the refrigerant circuit 10, a data mapping diagram stored in the database DB connected to the control device 100 can be used. When the control device 100 is input with information related to user-set heating requirements (set temperature and set airflow) and vehicle requirements as input information J, this information is compared with the operating state mapping diagram stored in the database DB to determine the target range of operating states that meet the requirements. Furthermore, when there are vehicle requirements such as improved COP and quiet driving, the operating state in which the compressor 2 speed is suppressed to the lowest level within the determined target range of operating states can be determined as the target operating state (PCO, PSO).

[0071] The following describes an example of control logic prior to determining the target operating state, but the embodiments of the present invention are not particularly limited. In the following example, a variable PSO control based on the premise of fixing the blow-out temperature according to the user-set heating requirements will be described.

[0072] like Figure 7As shown, when the control device 100 receives a user-set heating requirement as input information J, the target outlet temperature TAO is calculated based on the set temperature. Furthermore, the calculated target outlet temperature TAO is compared with the TAO / PCO mapping diagram 110 obtained from the database DB to determine the range of the target value PCO for the high-pressure side refrigerant pressure.

[0073] The TAO / PCO mapping diagram 110 used here can be used Figure 8 The data mapping diagram shown is a graph that maps the measured value of the high-pressure side refrigerant pressure Pci to the measured value of the compressor 2's outlet temperature. It is worth noting that the relationship between the measured value Pci and the outlet temperature, as shown in region M of the diagram, lies in the fact that the measured values ​​of Pci required to achieve the same outlet temperature are not in a fixed range. In the example shown, the measured values ​​of Pci required to achieve an outlet temperature of 55°C are in the range of 1.7 MPa to 1.9 MPa.

[0074] When Figure 8 When the mapping diagram shown is used as a TAO / PCO mapping diagram, it can specify the target value of the high-pressure refrigerant pressure used to keep the target blow-out temperature TAO constant within a range represented by upper and lower limits, relative to the input of the target blow-out temperature TAO. For example, when the target blow-out temperature TAO is fixed at 55°C, the target value of PCO corresponding to the target blow-out temperature TAO can be determined within the range of 1.7 MPa to 1.9 MPa.

[0075] Furthermore, the control device 100 further filters the range of the target value PCO determined by the TAO / PCO mapping diagram through the screening processing unit 111, and specifies the target operating state (PCO, PSO). The screening processing unit 111 uses the necessary capability TGQ that takes into account the vehicle requirements and the rotational speed limit requirement NC of the compressor 2 based on the vehicle requirements.

[0076] In the screening and processing unit 111, such as Figure 9 As shown, considering the necessary capability TGQ and speed limit requirement NC, a further selection range of PCO (e.g., from A1 to B1) is obtained relative to the target blow-out temperature TAO with a constant PCO range (from A0 to B0 in the figure). Figure 9 In this approach, with the premise of maintaining a constant target blowout temperature (TAO), increasing the target value (PCO) requires setting the rotational speed limit (NC) to a lower speed, or to a value lower than the necessary capability (TGQ). Conversely, increasing the target value (PCO) is achieved by decreasing both the rotational speed limit (NC) and the necessary capability (TGQ), thereby increasing the cost-effectiveness (COP).

[0077] exist Figure 9In the target value PCO range (from A0 to B0) where the target exhaust temperature TAO is constant, if the required NC speed limit is at its upper limit, the target value PCO value (A1) corresponding to that upper limit becomes the lower limit of the target value PCO range. Furthermore, within the target value PCO range (from A0 to B0) where the target exhaust temperature TAO is constant, if the required capability TGQ is at its lower limit, the target value PCO value (B1) corresponding to that lower limit becomes the upper limit of the target value PCO range. Additionally, if the vehicle requirements include improved COP and / or quiet driving, the NC speed limit requires selecting the lowest possible NC speed within the range; therefore, in the illustrated example, the target value PCO is specified as B1 and set as the target operating state.

[0078] Under the condition that the target blowing temperature TAO is constant, the relationship between the target value PCO and the target value PSO is as follows: Figure 10 The diagram shows an inverse linear relationship (in the figure, a1 < a2 < a3, b1 < b2 < b3). Using this linear relationship, a specific value of the target value PSO corresponding to a specific value of the target PCO is obtained, and their combination determines the target operating state (PCO, PSO).

[0079] In this way, in the variable PSO control after switching to the second selection mode, the target operating state (PCO, PSO) is determined by considering the user-set heating requirements (e.g., constant target blow-out temperature TAO) within a range that can maintain the user-set heating requirements (e.g., constant target blow-out temperature TAO), the necessary vehicle capability (TGQ), and the speed limit requirement (NC) based on vehicle requirements, and the control is performed with the measured value close to the target value of the determined target operating state. In this way, when there are requirements such as improved COP and quiet driving as vehicle requirements, the air conditioning control can meet the user-set heating requirements while suppressing the speed of compressor 2. Therefore, when the hot air heating operation mode is continuously operated, the reduction of the electric vehicle's driving range can be suppressed.

[0080] In the variable PSO control after switching to the second selection mode, a target operating state (PCO, PSO) is set that not only meets the heating requirements set by the user, but also meets the requirements of multiple vehicles. When the heating requirements set by the user or the vehicle requirements change, the necessary capacity TGQ is calculated according to the situation, and the speed limit requirement NC is confirmed to set a new target operating state (PCO, PSO).

[0081] According to the aforementioned vehicle air conditioning unit 1, when the hot air heating operation mode is selected, the system immediately transitions to the first selection mode in the aforementioned first judgment process S10A upon startup. Simultaneously, while the compressor 2 is selected at its maximum speed, the refrigerant circuit 10 is controlled to bring the measured pressure close to a fixed target pressure (e.g., the target value of the low-pressure side refrigerant pressure, PSO). Furthermore, if the hot air heating operation mode continues for a predetermined time, and the actual heating capacity Qhp increases to the point where the necessary capacity TGQ is exceeded, the aforementioned second judgment process S10B determines that there is an excess capacity and transitions to the second selection mode. As mentioned above, the target operating states (PCO, PSO) that satisfy the user-set heating requirements and vehicle requirements are set to be variable depending on the situation, and the system automatically transitions to variable PSO control. Moreover, after transitioning to the second selection mode, if the user-set heating requirements and vehicle requirements are changed, and the second judgment process S10B determines that there is no excess capacity, the system transitions from the second selection mode to the first selection mode.

[0082] Thus, according to the vehicle air conditioning unit 1, when the hot air heating operation mode is continuously running, it automatically completes the transition from the first selection mode to the second selection mode and from the second selection mode back to the first selection mode. However, maintaining the heating requirements set by the user becomes a prerequisite at this time. Therefore, the hot air heating operation mode can be continuously maintained without compromising user comfort. Furthermore, if the excess conditions in the second judgment process S10B are met, it automatically switches to control of the efficient refrigerant circuit 10 that meets various requirements. Therefore, user comfort can be ensured while performing operation that avoids excessive energy consumption.

[0083] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the specific structure is not limited to these embodiments. Even changes in design that do not depart from the spirit and scope of the present invention are included in the present invention.

[0084] Symbol Explanation

[0085] 1. Vehicle air conditioning unit; 2. Compressor; 10. Refrigerant circuit; 10V. Hot gas bypass path; 11. Outdoor heat exchanger; 12, 13. Flow path switching valves; 14, 15. Check valves; 16. Storage tank; 20. Indoor air conditioning unit; 21, 22. Indoor heat exchanger; 23. Blower; 24, 25. Air baffles; 25A, 25B. Air inlets; 30. Heat carrier circuit; 31. Circulation pump; 32. Heater; 33. Temperature-regulated object heat exchanger; 34. Refrigerant heat carrier heat exchanger; 34A, 34B. Flow paths; 40. Sensor unit; 41. External gas sensor; 42. Compressor current sensor; 43. Refrigerant temperature sensor; 44, 44A, 44B. Refrigerant pressure sensors; 45. Supply air temperature sensor; 100. Control device; J. Input information.

Claims

1. A vehicle air conditioning unit, comprising: A refrigerant circuit that reduces the pressure of the refrigerant discharged from the compressor and returns it to the compressor; A vehicle interior air conditioning system, wherein the vehicle interior air conditioning system regulates the temperature of the air supplied to the vehicle interior through the indoor heat exchange section of the refrigerant circuit; and A control device that controls the refrigerant circuit and the vehicle interior air conditioning system based on input information. Its features are, The refrigerant circuit includes a refrigerant flow path having a hot gas bypass path that depressurizes a portion of the refrigerant compressed in the compressor without passing through the indoor heat exchange section and allows it to flow to the suction side of the compressor. The refrigerant flow path is also capable of operating in a hot gas heating mode. In the hot gas heating operation mode, where a portion of the refrigerant compressed in the compressor flows to the indoor heat exchange section and the remaining refrigerant flows to the hot gas bypass path, the control device variably sets the target pressure of the refrigerant circuit within a range that can maintain the heating requirements, taking into account the necessary capacity determined based on the set heating requirements and vehicle requirements.

2. The vehicle air conditioning device as described in claim 1, characterized in that, The control device determines whether there is a surplus of capability to achieve the necessary requirements. When there is a surplus, the target pressure can be variably set. If there is no margin, the compressor speed is taken as the maximum speed and the target pressure is set to a fixed value.

3. The vehicle air conditioning device as described in claim 1, characterized in that, The heating requirements are specific based on the set temperature and set air volume.

4. The vehicle air conditioning device as described in claim 3, characterized in that, The control device determines the target range of high-pressure side refrigerant pressure that can maintain the set temperature. Within the target range, a target value for the high-pressure side refrigerant pressure is specified according to the vehicle requirements, and a target value for the low-pressure side refrigerant pressure is specified according to the specified target value for the high-pressure side refrigerant pressure.

5. The vehicle air conditioning device as described in claim 1, characterized in that, The refrigerant circuit includes a heat exchange section for temperature regulation of the on-board equipment. The vehicle requirements include requirements for temperature regulation of the on-board equipment and restrictions imposed by the vehicle.

6. The vehicle air conditioning device as described in claim 5, characterized in that, The aforementioned limitation requirement is a compressor speed limitation requirement that applies to one or both of the vehicle's quiet driving mode and increased COP operating mode.

Images