Vehicle air conditioning system

Abstract

The present application provides a kind of vehicle air conditioning system.In the first condition that the upper portion (20A) of grille damper or the lower portion (20B) of grille damper is fixed in open state and defrost function is opened, rear air conditioning operating part (121) can execute the air volume limit to the rear of carriage.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to Japanese Patent Application No. 2022-154320, filed on September 28, 2022, the entire contents of which, including the description, claims, drawings and abstract, are incorporated herein by reference. Technical Field

[0003] This specification discloses an air conditioning system for a vehicle. Background Technology

[0004] Vehicles are equipped with air conditioning (air conditioning) systems. For example, in battery electric vehicles (BEVs) that use a rotary electric motor instead of an internal combustion engine as a power source, since the heat generated by the internal combustion engine cannot be obtained, electric heaters such as PTC (Positive Temperature Coefficient) heaters are installed as heating devices.

[0005] For example, the electric heater has a heat source (such as a PTC element) that generates heat via an electrical supply. The refrigerant liquid is heated by flowing through the electric heater. The heated refrigerant liquid flows through piping before the front and rear blowers. As the air delivered from the blowers passes through the piping, it exchanges heat with the refrigerant liquid, becoming warm air. This warm air is supplied to the front and rear spaces of the passenger compartment.

[0006] In addition, conventional heat exchange-type air conditioning systems in vehicles include a heat exchanger. This heat exchanger is located in the engine compartment. A front grille is installed on the front surface of the engine compartment, i.e., the front surface of the vehicle. External air introduced into the engine compartment through the front grille exchanges heat with the heat exchanger.

[0007] Here, if the layout of a heat exchange type air conditioning system is applied to an electric heater system, for example, the electric heater is mounted in the electric motor compartment of an electric vehicle instead of a heat exchanger. Furthermore, both the engine compartment and the electric motor compartment are compartments housing the drive source; therefore, these compartments are collectively referred to as the engine room.

[0008] To achieve rapid heating (preheating) of equipment inside the engine compartment, for example, as described in Japanese Patent Application Publication No. 2021-131051, a grille damper is provided behind the front grille. By adjusting the opening of the grille damper, the amount of outside air introduced into the engine compartment from the front grille can be adjusted.

[0009] However, sometimes the blades of the grille damper may become fixed in an open position. This "fixed in an open position" refers to a situation where the open blades remain fixed in an open state even after receiving a closing command. This can occur due to foreign objects such as snow clumps trapped between adjacent blades in the open state, or a malfunction in the actuator that rotates the blades.

[0010] Because the blades are fixed in place, external air enters the internal combustion engine compartment. This draws heat away from the heat source in the electric heater, potentially inhibiting its heating function. This is especially true when performing the defrosting function, which acts as an anti-fog function for the windshield, where the electric heater is needed to fully heat the refrigerant.

[0011] Therefore, this specification discloses a vehicle air conditioning system that, when the heat source of the air conditioning system is located in the engine compartment, can reliably perform defogging by a defroster when the blades of the grille damper are fixed in place. Summary of the Invention

[0012] The vehicle air conditioning system disclosed in this specification includes a grille damper, a heat source, recirculation piping, a front blower, a rear blower, a front air conditioning control unit, and a rear air conditioning control unit. The grille damper is located on the front surface of the engine compartment, which is located at the front of the vehicle and has a drive source, and can adjust the amount of external gas introduced into the engine compartment. The heat source is located in the engine compartment. The recirculation piping is piping for the flow of refrigerant liquid and has a heating zone via the heat source. Furthermore, the recirculation piping branches from the heating zone into a front compartment and a rear compartment before rejoining and returning to the heating zone. The front blower exchanges heat with the refrigerant liquid flowing in the front compartment to deliver warm air to the front of the compartment. The rear blower exchanges heat with the refrigerant liquid flowing in the rear compartment to deliver warm air to the rear of the compartment. The front air conditioning control unit can operate the airflow to the front of the compartment, including turning the defrost function on / off. The rear air conditioning control unit can operate the airflow to the rear of the compartment. Furthermore, when the first condition is met—that the grille damper is fixed in the open state and the defrosting function is in the on state—the rear air conditioning control unit can restrict the airflow to the rear of the vehicle compartment.

[0013] According to the above structure, when the grille damper is fixed open, the amount of warm air directed towards the rear of the vehicle compartment is limited, thereby suppressing the heat exchange (i.e., temperature drop) of the refrigerant liquid. As a result, the fully heated warm air can be used by the defroster.

[0014] Alternatively, in the above structure, when the first condition is met and the second condition (the outside temperature is below the threshold temperature) is met, the rear air conditioning control unit can perform airflow restriction to the rear of the vehicle compartment.

[0015] Based on the above structure, when the outside temperature exceeds the threshold temperature, it can avoid limiting the airflow to the rear of the vehicle and suppress the decrease in comfort of the rear seats.

[0016] Alternatively, in the above structure, when the first and second conditions are met and the third condition (vehicle speed exceeding the threshold speed) is met, the rear air conditioning control unit may restrict the airflow to the rear of the vehicle compartment.

[0017] Based on the above structure, when the vehicle speed is less than the threshold speed, the airflow restriction to the rear of the passenger compartment can be avoided, and the decrease in comfort of the rear seats can be suppressed.

[0018] According to this manual, the vehicle air conditioning system, when the heat source of the air conditioning system is located in the engine compartment, can reliably perform anti-fogging by the defroster when the blades of the grille damper are fixed open. Attached Figure Description

[0019] Figure 1 This is a diagram illustrating the structure of the engine compartment of a vehicle.

[0020] Figure 2 This is a diagram illustrating an air conditioning system, particularly its circulating piping.

[0021] Figure 3 This is a diagram illustrating the structure of the front part of the carriage.

[0022] Figure 4 This is a diagram illustrating the structure of the rear section of the carriage.

[0023] Figure 5 This is a diagram illustrating the overall structure of the vehicle air conditioning system according to this embodiment.

[0024] Figure 6 This is a diagram illustrating the hardware structure of an air conditioning ECU.

[0025] Figure 7 This diagram illustrates the setting of the threshold temperature To_th for the outside air temperature.

[0026] Figure 8 This diagram illustrates the setting of the threshold speed V_th for vehicle speed.

[0027] Figure 9 This is a diagram illustrating the rear airflow limitation determination process performed by the vehicle air conditioning system of this embodiment. Detailed Implementation

[0028] The following description uses the accompanying drawings to illustrate an embodiment of a vehicle air conditioning system. The shapes, materials, quantities, and values ​​described below are illustrative and can be appropriately varied depending on the specifications of the vehicle air conditioning system. Furthermore, the same reference numerals are used to denote the same elements in all the accompanying drawings.

[0029] In addition, Figures 1-4 In this coordinate system, an orthogonal coordinate system consisting of the FR axis, RW axis, and UP axis is used to represent the position and orientation of each structure. The FR axis is the vehicle's front-to-rear direction axis with the front of the vehicle as the positive direction. The RW axis is the vehicle's width direction axis with the right side of the vehicle as the positive direction. The UP axis is the vehicle's vertical direction axis with the top as the positive direction.

[0030] <Overall Structure>

[0031] Figure 5 The overall overview of the vehicle air conditioning system of this embodiment is illustrated below. Specifically, the air conditioning system includes an electric heater 30, a circulation piping 40, a front blower 80A, and a rear blower 80B as mechanisms for supplying warm air. Furthermore, the air conditioning system includes a front air conditioning control panel 50, a rear air conditioning control panel 60, a front operation control unit 70, a rear operation control unit 71, and an air conditioning ECU 100 as mechanisms for controlling the airflow volume and destination of the warm air. Moreover, the air conditioning system includes an upper grille damper 20A and a lower grille damper 20B, which are adjusted and inserted into the engine compartment 12 where the electric heater 30 is installed (see reference 12). Figure 1 The mechanism for measuring the flow rate of external gases (hereinafter referred to as external gas volume).

[0032] If the defrost button 58A on the front air conditioning control panel 50 (refer to...) Figure 3 If the opening operation is performed, the air conditioning ECU100 determines whether at least one of the upper grille damper 20A and the lower grille damper 20B is fixed open.

[0033] Then, when the defrosting function is on and at least one of the upper grille damper 20A and the lower grille damper 20B is fixed (when the first condition is met), the rear operation control unit 71 can perform airflow restriction to the rear of the vehicle compartment.

[0034] <Engine compartment>

[0035] Figure 1 An example is shown of equipment located in the engine compartment 12 of a vehicle 10. The vehicle 10 is, for example, a battery electric vehicle (BEV) powered by a rotary motor 110. The vehicle 10 has an engine compartment 12 as a compartment housing the rotary motor 110. The engine compartment 12 is also referred to as the electric motor compartment. Furthermore, the engine compartment 12 is located at the front of the vehicle 10. For example, see reference... Figure 2The engine compartment 12 is located forward of the carriage 16.

[0036] Reference Figure 1 A front grille is provided on the front surface of the engine compartment 12. As described above, since the engine compartment 12 is located at the front of the vehicle 10, the front grille provided on the front surface of the engine compartment 12 is positioned at the front of the vehicle 10.

[0037] For example in Figure 1 In this example, the front grille is divided into upper and lower layers. That is, an upper front grille 14A as the upper grille and a lower front grille 14B as the lower grille are provided on the front surface of the engine compartment 12. The upper front grille 14A and the lower front grille 14B extend along the width direction of the vehicle on the front surface of the vehicle.

[0038] A radiator upper part 15A and a radiator lower part 15B are provided behind the upper part 14A and the lower part 14B of the front grille. The radiator upper part 15A and the radiator lower part 15B are located in the engine compartment 12 to cool the electrical equipment of the vehicle 10. For example, refrigerant cooling the rotary motor 110 flows into the radiator upper part 15A and exchanges heat with the outside air. Similarly, refrigerant cooling high-voltage electronic equipment such as inverters and DC / DC converters flows into the radiator lower part 15B and exchanges heat with the outside air.

[0039] On the front surface of the engine compartment 12, an upper grille damper 20A and a lower grille damper 20B are provided between the upper front grille 14A and the lower front grille 14B and the upper radiator 15A and the lower radiator 15B. The upper grille damper 20A and the lower grille damper 20B are equipped with controllers 22A and 22B, actuators 24A and 24B, and blades 25A and 25B.

[0040] Blades 25A and 25B extend over the entire width (full length in the RW direction) of the grille openings, for example, in the upper front grille 14A and the lower front grille 14B. Controllers 22A and 22B are connected from the air conditioning ECU 100 (see reference). Figure 5 The actuators 24A and 24B are driven by drive commands. For example, drive commands include open and close commands. Based on the drive control of the controllers 22A and 22B, the actuators 24A and 24B cause the blades 25A and 25B to open and close. The amount of outside gas introduced into the engine compartment 12 can be adjusted according to the opening and closing of the blades 25A and 25B.

[0041] <Air Conditioning System>

[0042] Reference Figure 1 , Figure 2The vehicle 10 is equipped with an air conditioning system (air conditioning system) for the passenger compartment 16. As part of the heating function of this air conditioning system, the vehicle 10 is equipped with an electric heater 30, a circulation pipe 40, a pump 41, a front blower 80A, and a rear blower 80B. Furthermore, for the sake of simplicity, in... Figure 2 The illustrations of air guiding units such as pipes and pipe doors are omitted.

[0043] The electric heater 30 includes PTC elements 32A-32D as a heat source. The PTC elements 32A-32D are heating elements that are heated by electrical power, and their resistance value is known to vary with temperature.

[0044] For example, when power is supplied to PTC elements 32A-32D, the temperature rises, and when this temperature exceeds a specified threshold temperature, the resistance increases sharply. As a result, the current supplied to PTC elements 32A-32D at the same voltage is reduced, and the temperature rise is suppressed. By using PTC elements 32A-32D with a target temperature set at the threshold temperature, the current is reduced after the target temperature is reached, thus suppressing temperature rise above the target temperature.

[0045] For example, the electric heater 30 includes multiple PTC elements 32A-32D as a heat source. Furthermore, the electric heater 30 is equipped with a switch panel 35 for switching the supply / disconnection of current (see reference). Figure 5 As will be described later, the air conditioning ECU100 selects the PTC elements 32A-32D for which current is supplied based on the required temperature rise of the refrigerant liquid.

[0046] The electric heater 30 includes a housing 31 that houses the PTC elements 32A-32D. The housing 31 is made of a metal material such as aluminum. Inside the housing 31, as part of the circulation piping 40, a heating zone 42 is provided via a heat source. For example, piping that contacts the PTC elements 32A-32D, which serve as the heat source, is provided inside the housing 31. The extension of this piping forms the heating zone 42.

[0047] Furthermore, the electric heater 30 is located in the engine compartment 12. Therefore, heat is drawn from the electric heater 30 and the PTC elements 32A-32D, which serve as heat sources, by the outside air introduced from the upper front grille 14A and the lower front grille 14B. As a result, the rate of refrigerant temperature rise may be slowed down. In particular, when at least one of the upper grille damper 20A and the lower grille damper 20B becomes open or closed, adjusting the amount of outside air becomes difficult, and correspondingly, the electric heater 30 may be exposed to a large amount of outside air.

[0048] Therefore, as described later, when at least one of the upper grille damper 20A and the lower grille damper 20B is fixed in place, and the defrosting function of the air conditioning system is activated, airflow restriction towards the rear of the passenger compartment 16 can be implemented. This airflow restriction suppresses heat exchange (i.e., temperature reduction) of the refrigerant liquid. As a result, sufficiently heated warm air can be used by the defroster.

[0049] The circulating piping 40, which serves as the flow path for the refrigerant liquid, includes a heating zone 42, a front section 44, and a rear section 46. As described above, the heating zone 42 is located within the electric heater 30. The refrigerant liquid, heated by passing through the heating zone 42, is branched into the front section 44 and the rear section 46. The front section 44 extends across the air outlet of the front blower 80A, and the rear section 46 extends across the air outlet of the rear blower 80B. Subsequently, the front section 44 and the rear section 46 converge downstream and return to the heating zone 42.

[0050] The flow rate of the refrigerant liquid flowing in the circulating piping 40 is controlled by pump 41. (Refer to...) Figure 5 Pump 41 is connected to pump motor 43. Pump motor 43 is controlled to rotate by pump inverter 45.

[0051] For example, a PWM signal is output from the device control unit 106 of the air conditioning ECU 100. The switching element of the pump inverter 45 is driven according to the PWM signal. Then, a voltage corresponding to the duty cycle of the PWM signal is applied to the pump motor 43, and a driving force corresponding to the applied voltage is input to the pump 41.

[0052] Reference Figure 2 The front blower 80A is, for example, housed in the dashboard 115 in front of the carriage 16 (see reference). Figure 3 Furthermore, the front section 44 of the circulation piping 40 is also housed in the instrument panel 115.

[0053] The air delivered by the blower 80A exchanges heat with the refrigerant liquid as it passes through the front section 44 of the carriage, becoming warm air. This warm air is then directed towards the front of the carriage from the nozzles of the ventilation device (not shown) and other components located on the instrument panel 115.

[0054] Additionally, a section facing the windshield 11 is provided at the front end of the instrument panel 115 (see reference). Figure 3 The air outlet 13 delivers air from the front blower 80A. For example, if the defrost button 58A of the front air conditioning control panel 50 is activated, the duct door (not shown) in the instrument panel 115 opens and closes, and warm air is blown out from the air outlet 13.

[0055] The rear blower 80B, for example, is located in the front armrest box 117 along with the rear compartment 46 of the circulation piping 40 (see reference). Figure 3 The lower part of the compartment. The air delivered from the rear blower 80B exchanges heat with the refrigerant liquid as it passes through the rear compartment 46 of the carriage, becoming warm air. This warm air is delivered to the rear of the carriage from an air outlet (not shown) located on the back of the front armrest box 117.

[0056] like Figure 5 As illustrated, the front blower 80A is connected to the front motor 82A. The front motor 82A is controlled to rotate by the front inverter 84A. Similarly, the rear blower 80B is connected to the rear motor 82B. The rear motor 82B is controlled to rotate by the rear inverter 84B.

[0057] For example, a PWM signal is output from the device control unit 106 of the air conditioning ECU 100. The switching elements of the front inverter 84A and the rear inverter 84B are driven according to the PWM signal. Moreover, a voltage corresponding to the duty cycle of the PWM signal is applied to the front motor 82A and the rear motor 82B, and a driving force corresponding to the applied voltage is input to the front blower 80A and the rear blower 80B.

[0058] <Air Conditioning Operations Department>

[0059] exist Figure 3 The diagram illustrates a front air conditioning control panel 50, which is part of a vehicle air conditioning system according to this embodiment. For example, the front air conditioning control panel 50 is located on the instrument panel 115. This front air conditioning control panel 50 and the front operation control unit 70 (see reference 115) form the basis of the system. Figure 5 This constitutes the front air conditioning control unit 120.

[0060] The front air conditioning control panel 50 may be, for example, a touch panel where the input and display sections overlap. The front air conditioning control panel 50 can control the airflow towards the front of the vehicle, including turning the defrost function on / off.

[0061] For example, the front air conditioning control panel 50 includes airflow setting buttons 51A and 51B, temperature setting buttons 52A and 52B, an automatic button 53, and a blower button 54. Furthermore, the front air conditioning control panel 50 includes an air conditioning button 55, an indoor / outdoor air switching button 56, a display 57, a defrost button 58A, a rear defrost button 58B, and an air outlet selection switch 59. The functions of these buttons and switches are known, and therefore descriptions are omitted here.

[0062] The operation signals for the various buttons on the front air conditioning control panel 50 are provided by the front operation control unit 70 (see reference). Figure 5 The front operation control unit 70 may be, for example, a computer installed on the front air conditioning control panel 50. For example, the front operation control unit 70 stores operation signals input from various buttons on the front air conditioning control panel 50 and sends the operation signals to the air conditioning ECU 100.

[0063] exist Figure 4 The diagram illustrates a rear air conditioning control panel 60, which is part of the vehicle air conditioning system according to this embodiment. For example, the rear air conditioning control panel 60 is located on a rear console 65. For example, the rear console 65 is located between a pair of rear seats 19, 19. This rear air conditioning control panel 60 and the rear operation control unit 71 (see reference 71) are used to connect the rear air conditioning control panel 60 and the rear operation control unit 71. Figure 5 The rear air conditioning control unit 121 is formed.

[0064] The rear air conditioning control panel 60 may be, for example, a touch panel where the input and display sections overlap. The rear air conditioning control panel 60 allows for control of the airflow to the rear of the vehicle. For example, the rear air conditioning control panel 60 may include airflow setting buttons 61A and 61B, temperature setting buttons 62A and 62B, an automatic button 63, and an airflow selection switch 69. The functions of these buttons and switches are known, and therefore descriptions are omitted here.

[0065] The operation signals for the various buttons on the rear air conditioning control panel 60 are provided by the rear operation control unit 71 (see reference). Figure 5 The rear operation control unit 71 may be, for example, a computer installed on the rear air conditioning control panel 60. This computer may, for example, have... Figure 6 The hardware structure shown is an example.

[0066] For example, the rear operation control unit 71 stores operation signals input from various buttons on the rear air conditioning control panel 60 and sends the operation signals to the air conditioning ECU 100.

[0067] Furthermore, as described later, the rear operation control unit 71 can perform airflow restriction on the rear air conditioning, i.e., the amount of warm air directed towards the rear of the vehicle compartment. For example, refer to... Figure 4 Without applying an airflow limit, the airflow can be set from 0 to 5 using the airflow setting buttons 61A and 61B. However, when the airflow limit is applied, the maximum airflow is limited to 3. In other words, even if the occupant wants to increase the airflow from 3 using the airflow setting button 61A, the rear operation control unit 71 will disable such an operation. Details of this airflow limit will be described later.

[0068] <Air Conditioning ECU>

[0069] The air conditioning ECU 100 is an electronic control unit that controls the vehicle's air conditioning system. For example, the air conditioning ECU 100 is composed of a computer and possesses features such as... Figure 6 The hardware structure is as illustrated. That is, the air conditioning ECU 100 includes an input / output controller 100C, a CPU 100D, a RAM 100E, a ROM 100F, and a storage device 100G. These electronic components are connected via an internal bus 100H.

[0070] Reference Figure 5The air conditioning ECU 100 is connected to the switch panel 35, the pump inverter 45, and the refrigerant temperature sensor 92 to control the electric heater 30. In addition, the air conditioning ECU 100 is connected to the front room temperature sensor 90A, the rear room temperature sensor 90B, the front inverter 84A, and the rear inverter 84B to control the front blower 80A and the rear blower 80B.

[0071] Furthermore, the air conditioning ECU 100, as the connection point of the air conditioning operating system, is connected to the front air conditioning control panel 50 via the front operation control unit 70. Additionally, the air conditioning ECU 100 is connected to the rear air conditioning control panel 60 via the rear operation control unit 71.

[0072] In addition, to control the amount of outside air introduced into the engine compartment 12, the air conditioning ECU 100 is connected to controllers 22A and 22B of the upper grille damper 20A and the lower grille damper 20B. Furthermore, the air conditioning ECU 100 is connected to speed sensors 26A and 26B, which determine whether the blades 25A and 25B can rotate.

[0073] Speed ​​sensors 26A and 26B, for example, are equipped with Hall elements. Furthermore, speed sensors 26A and 26B output pulse signals based on their relative distance to magnets (not shown) disposed on the rotors of actuators 24A and 24B.

[0074] In addition, the air conditioning ECU 100 is connected to the vehicle speed sensor 96 and the outside temperature sensor 94 in order to obtain the values ​​(vehicle speed and outside temperature) used in the determination of whether the rear air conditioning air volume limit is possible, which will be described later.

[0075] The CPU100D executes the ROM100F stored in the air conditioning ECU100 (see reference). Figure 6 The control program of the storage device 100G is built in the air conditioning ECU100. Figure 5 The illustrated function blocks. Alternatively, these function blocks can also be constructed by the CPU100D reading and executing control programs stored on non-transitory computer-readable storage media such as DVDs.

[0076] The air conditioning ECU 100 includes a damper determination unit 101, an outside temperature determination unit 102, a vehicle speed determination unit 103, a previous value storage unit 104, an air conditioning control determination unit 105, and an equipment control unit 106. Through these function blocks, the rear air conditioning airflow limit determination process described below is executed.

[0077] <Rear Air Conditioner Airflow Limitation Determination Process>

[0078] Figure 9The following describes a process for determining the rear air conditioning airflow limit using the vehicle air conditioning system of this embodiment. In this process, when the grille damper is fixed open, if it is anticipated that the warm air intended for defrosting will have difficulty heating up, the rear air conditioning, i.e., the airflow to the rear of the vehicle compartment, is limited. Furthermore, this process is repeated as indicated by the "Return" at the end.

[0079] Reference Figure 5 , Figure 9 The damper determination unit 101 determines whether the upper part 20A of the grille damper has been opened and closed (S10). For example, the damper determination unit 101 determines whether the blade 25A is in an open state based on the operation history of the blade 25A obtained from the speed sensor 26A.

[0080] Furthermore, when the blade 25A is in the open state, the damper determination unit 101 sends a drive command (closing command) to the controller 22A to confirm operation. Upon receiving the drive command, the controller 22A drives the actuator 24A to rotate the blade 25A to the closed state.

[0081] Whether the blade 25A rotates is detected by the speed sensor 26A. If the damper determination unit 101 does not output a pulse signal from the speed sensor 26A within a specified time from the time the drive signal is sent to the controller 22A, it determines that the upper part 20A of the grille damper is in the open fixed state.

[0082] When it is determined that the upper part 20A of the grille damper has not been fixed, the damper determination unit 101 then determines whether the lower part 20B of the grille damper has been fixed (S12). In this fixation determination, the same processing as that for the fixation determination of the upper part 20A of the grille damper is performed.

[0083] When it is determined that the upper part 20A or the lower part 20B of the grille damper has been opened or closed, the air conditioning control determination unit 105 determines whether the defrosting function is in the on state based on the history of operation signals stored in the front operation control unit 70 (S14). For example, the air conditioning control determination unit 105 confirms the defrosting button 58A (see reference) based on the operation history of the front operation control unit 70. Figure 3 Whether to keep it in the on state.

[0084] The first condition is that the upper part 20A of the grille damper or the lower part 20B of the grille damper is fixed in the open state and the defrosting function is in the active state. When this first condition is met, the rear operation control unit 71 can perform airflow restriction to the rear of the vehicle compartment.

[0085] exist Figure 9In the flowchart, in addition to the first condition, there are also determination steps for a second condition (S16) related to the outside temperature and a third condition (S18) related to the vehicle speed. The outside temperature determination unit 102 determines whether the outside temperature To obtained from the outside temperature sensor 94 is below a predetermined threshold temperature To_th (S16).

[0086] Here, the threshold temperature To_th can be set using a so-called hysteresis setting. Figure 7 Two threshold temperatures, To_th1 and To_th2, are shown. The outside temperature determination unit 102 refers to the previous value storage unit 104 to determine whether the outside temperature To during the previous process execution exceeded the threshold temperature To_th2. If the previous outside temperature To exceeded the threshold temperature To_th2, in step S16, the threshold temperature To_th1 is set as the current threshold temperature. If the previous outside temperature To was below the threshold temperature To_th2, in step S16, the threshold temperature To_th2 ​​is set as the current threshold temperature.

[0087] In step S16, when the outside temperature To exceeds the threshold temperature To_th (To_th1 or To_th2), that is, when the outside air is appropriately warm, the execution of the airflow restriction is suspended.

[0088] If the condition that the outside temperature To is below the threshold temperature To_th is set as the second condition, then when both the first condition (grille damper open and defrost on) and the second condition are met, the rear operation control unit 71 can perform airflow restriction to the rear of the vehicle compartment. Furthermore, in Figure 9 In the flowchart, in addition to the first and second conditions, there is also a determination step for a third condition (S18) related to vehicle speed.

[0089] The vehicle speed determination unit 103 determines whether the vehicle speed V obtained from the vehicle speed sensor 96 is above a predetermined threshold speed V_th (S18). Here, similar to step S16, the threshold speed V_th can be set with a lag. Figure 8 Two threshold speeds, V_th1 and V_th2, are shown. The vehicle speed determination unit 103 refers to the previous value storage unit 104 to determine whether the vehicle speed V during the previous execution process is greater than or equal to the threshold speed V_th2. If the previous vehicle speed V is greater than or equal to the threshold speed V_th2, the threshold speed V_th1 is set as the current threshold speed in step S18. If the previous vehicle speed V is less than the threshold speed V_th2, the threshold speed V_th2 is set as the current threshold speed in step S18.

[0090] In step S18, if the vehicle speed V is less than the threshold speed V_th (V_th1 or V_th2), the execution of the rear airflow restriction is suspended. If the condition that the vehicle speed V is greater than or equal to the threshold speed V_th is set as the third condition, then when the first condition (grille damper open and defrost on) and the second condition (outdoor temperature To ≤ To_th) are met, and the third condition is met, the rear operation control unit 71 executes the airflow restriction to the rear of the vehicle compartment.

[0091] For example, refer to Figure 4 When the airflow is limited, the rear operation control unit 71 limits the upper limit airflow to 3. Even if an occupant wants to increase the airflow from 3 using the airflow setting button 61A, the rear operation control unit 71 disables such an operation (maintaining it at 3). Then, the rear operation control unit 71 does not send the operation signal to the air conditioning ECU 100 at this time. Furthermore, the rear operation control unit 71 displays the screen 67 (see reference...) Figure 4 This message indicates that the maximum airflow limit under the airflow restriction is 3.

[0092] In addition, Figure 9 In the flowchart, when the first condition (grille damper fixed and defrost activated), the second condition (outdoor temperature To ≤ To_th), and the third condition (vehicle speed V ≥ V_th) are all met, the airflow restriction to the rear of the vehicle compartment is implemented. However, the vehicle air conditioning system of this embodiment is not limited to this embodiment.

[0093] For example, the rear operation control unit 71 may also perform airflow restriction if the first condition is met. Alternatively, the rear operation control unit 71 may perform airflow restriction if both the first and second conditions are met. In either case, in the vehicle air conditioning system of this embodiment, from the viewpoint of ensuring the heating function of the electric heater 30, it is determined whether various conditions are met.

[0094] Here, it is assumed that the temperature sensor 92 (reference) is set. Figure 5 In the case of a process that obtains the refrigerant temperature and determines whether airflow restriction can be implemented based on a comparison with the threshold temperature, the time it takes for the refrigerant temperature to temporarily drop and then recover to a sufficient temperature may be reduced during this period.

[0095] In contrast, Figure 9 The flowchart does not include a step for using refrigerant temperature; instead, it focuses on determining whether airflow limitation is feasible based on factors that suppress the temperature rise of the electric heater 30. Through this determination, the electric heater 30 can reliably heat the refrigerant liquid at all times.

[0096] This disclosure is not limited to the above-described embodiments, but includes all changes and modifications without departing from the technical scope or essence of the invention as defined by the claims.

Claims

1. A vehicle air conditioning system, comprising: The grille damper is located on the front surface of the engine compartment, which is located at the front of the vehicle and has a drive source, and can adjust the amount of external gas introduced into the engine compartment. The heat source is located in the engine compartment; The circulating piping is a piping for the flow of refrigerant liquid, having a heating zone via the heat source, and branching from the heating zone into a front section and a rear section of the carriage before merging back into the heating zone; The front blower exchanges heat with the refrigerant liquid flowing in the section in front of the carriage to deliver warm air to the front of the carriage; The rear blower exchanges heat with the refrigerant liquid flowing in the rear section of the carriage to deliver warm air to the rear of the carriage; The front air conditioning control unit is capable of controlling the airflow towards the front of the vehicle, including turning the defrost function on / off. and The rear air conditioning control unit is capable of adjusting the airflow to the rear of the vehicle compartment. When the first condition is met—that the grille damper is fixed in the open state and the defrosting function is in the active state—the rear air conditioning control unit can perform airflow restriction to the rear of the vehicle compartment.

2. The vehicle air conditioning system according to claim 1, wherein, When the first condition is met and the second condition (outside temperature below a threshold temperature) is met, the rear air conditioning control unit can perform airflow restriction to the rear of the vehicle compartment.

3. The vehicle air conditioning system according to claim 2, wherein, When the first and second conditions are met and the third condition of the vehicle speed reaching or exceeding the threshold speed is met, the rear air conditioning control unit performs airflow restriction to the rear of the vehicle compartment.

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