Air conditioner

Abstract

To provide an air conditioner capable of suppressing excessive heating of blown air by an air heater.SOLUTION: The control unit determines an estimated value of the heater core inlet liquid temperature TW required for setting the air heater outlet temperature to the target outlet temperature TAO when the air heater 28 is turned off, as the inlet liquid temperature upper set value TWO. Further, the control unit determines an estimated value of the heater core inlet liquid temperature TW required for setting the air heater outlet temperature to the target air outlet temperature TAO when the air heater 28 heats the ventilation air at the air heater maximum output Pam, as an inlet liquid temperature lower set value TWOb. Then, the control unit operates the air heater 28 so as to converge the air heater outlet temperature to the target outlet temperature TAO in accordance with the heater core inlet fluid temperature TW, the inlet fluid temperature upper set value TWO, and the inlet fluid temperature lower set value TWOb.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to an air conditioning system that heats a vehicle interior by utilizing waste heat from an object to be cooled. [Background technology]

[0002] An example of this type of air conditioning system is the air conditioning system described in Patent Document 1. The air conditioning system described in Patent Document 1 includes a fuel cell, a heater core, and a water heater, which are arranged on a water passage. The fuel cell is cooled by coolant circulating through the water passage. The heater core uses the coolant discharged from the fuel cell as a heat source to heat the air to be blown into the vehicle cabin, and the water heater heats the coolant discharged from the fuel cell and flowing into the heater core. The air conditioning system described in Patent Document 1 also includes an air heater that further heats the air to be blown that has been heated by the heater core, and a control unit.

[0003] Furthermore, the control unit performs heating control to operate the air heater and the water heater when the estimated coolant temperature at the heater core coolant outlet based on the air conditioning setting temperature corresponding to the target blowout temperature is equal to or higher than the target coolant temperature at the fuel cell coolant inlet. Specifically, in this heating control, the control unit operates the air heater with an output set based on the estimated coolant temperature at the heater core coolant outlet. At the same time, the control unit operates the water heater with an output set based on the target coolant temperature at the heater core coolant inlet calculated in accordance with the set air heater output. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-93592 Summary of the Invention [Problem to be solved by the invention]

[0005] In the air conditioning system of Patent Document 1, as described above, the air heater is activated when the estimated temperature of the coolant at the coolant outlet of the heater core is equal to or higher than the target temperature of the coolant at the coolant inlet of the fuel cell. Therefore, the temperature of the blown air heated by the air heater may exceed the target blown air temperature. In such a case, the blown air heated by the air heater must be cooled by blown air that bypasses the air heater and heater core before being circulated into the vehicle cabin.

[0006] That is, in the air conditioner of Patent Document 1, the blown air may be excessively heated by the air heater. This reduces the energy efficiency of the air conditioner, and as a result, leads to a decrease in fuel efficiency of the vehicle equipped with the air conditioner of Patent Document 1. The inventors have found the above as a result of detailed studies.

[0007] In view of the above, an object of the present disclosure is to provide an air conditioner that can prevent an air heater corresponding to the air heater from excessively heating the blown air. [Means for solving the problem]

[0008] In order to achieve the above object, an air conditioner according to one aspect of the present disclosure comprises: An air conditioning device for a vehicle, a heater core (27) provided in a liquid circuit (3) through which a liquid medium for cooling an object to be cooled (6) circulates, the heater core (27) using the liquid medium flowing out of the object to be cooled as a heat source to heat the blown air to be blown into the vehicle interior; an air heater (28) for further heating the blown air heated by the heater core; a control unit (5), The control unit is determining an estimated value of the heater core inlet liquid temperature (TW) required to make the temperature of the blown air flowing out from the air heater equal to the target outlet temperature (TAO) when the air heater is turned off as an inlet liquid temperature upper set value (TWO); The estimated value of the heater core inlet liquid temperature required to make the temperature of the blown air flowing out from the air heater the target blown air temperature under a predetermined heating operation condition in which the air heater heats the blown air is set to the inlet liquid temperature lower set value (TWOb, TWO n ) and The air heater is operated in accordance with the inlet liquid temperature, the inlet liquid temperature upper set value, and the inlet liquid temperature lower set value so that the temperature of the blown air flowing out from the air heater converges to a target blown temperature.

[0009] This prevents the air heater from heating the blown air so that the temperature of the blown air flowing out from the air heater exceeds the target blown air temperature, thereby preventing the air heater from excessively heating the blown air.

[0010] Furthermore, an air conditioning device according to another aspect of the present disclosure includes: An air conditioning device for a vehicle, a heater core (27) provided in a liquid circuit (3) through which a liquid medium for cooling an object to be cooled (6) circulates, the heater core (27) using the liquid medium flowing out of the object to be cooled as a heat source to heat the blown air to be blown into the vehicle interior; an air heater (28) for further heating the blown air heated by the heater core; a flow rate adjusting device (32) capable of increasing or decreasing a heater core liquid flow rate (Vw), which is the flow rate of the liquid medium flowing through the heater core; a control unit (5), The control unit is determining an estimated heater core fluid flow rate required to bring the temperature of the blown air flowing out of the air heater to the target outlet temperature (TAO) when the air heater is turned off as an upper setpoint flow rate (VWO); determining, as a lower setpoint flow rate (VWOb), an estimated value of the heater core liquid flow rate required to make the temperature of the blown air flowing out from the air heater reach the target blown air temperature under a predetermined heating operating condition in which the air heater heats the blown air; The larger of the lower limit value (Vwmin) of the heater core liquid flow rate and the lower set value of the flow rate is set as the flow rate target value, and the liquid medium is circulated by controlling the flow rate adjustment device so that the heater core liquid flow rate converges to the flow rate target value. The air heater is operated in accordance with the lower limit value of the heater core liquid flow rate, the upper flow rate setting value, and the lower flow rate setting value so that the temperature of the blown air flowing out from the air heater converges to a target blown temperature.

[0011] This also prevents the air heater from heating the blown air so that the temperature of the blown air flowing out from the air heater exceeds the target blown air temperature, thereby preventing the air heater from excessively heating the blown air.

[0012] In addition, in each section of the application documents, each element may be assigned a reference number in parentheses. In this case, the reference number merely indicates an example of the correspondence between the element and the specific configuration described in the embodiment described below. Therefore, the present disclosure is not limited in any way by the description of the reference number. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a cross-sectional view that schematically shows the general configuration of an air conditioning unit included in an air conditioner of a first embodiment. [Figure 2] 1 is a circuit diagram showing a schematic configuration of a liquid circuit included in an air conditioner of a first embodiment. [Figure 3] 3 is a diagram showing the switching state of a flow path switching valve of the liquid circuit in FIG. 2 when the liquid circuit is set to a linked mode. FIG. [Figure 4] 3 is a diagram showing the switching state of a flow path switching valve of the liquid circuit in FIG. 2 when the liquid circuit is set to the independent mode. FIG. [Figure 5] 3 is a flowchart showing a control process executed by a control unit included in the air conditioner of the first embodiment. [Figure 6]FIG. 6 is a diagram schematically showing a first inlet liquid temperature estimation map used to determine the inlet liquid temperature upper set value in step S102 of FIG. 5. [Figure 7] FIG. 6 is a diagram schematically showing an air heater inlet temperature estimation map used to determine the air heater inlet target temperature in step S103 of FIG. 5. [Figure 8] FIG. 6 is a diagram schematically showing a liquid flow rate map used to estimate the heater core liquid flow rate in step S104 of FIG. 5. [Figure 9] 6 is a diagram schematically showing a second inlet liquid temperature estimation map used to determine the inlet liquid temperature lower set value in step S104 of FIG. 5. FIG. [Figure 10] 6 is a diagram showing a schematic diagram of the relationship between the air heater output determined based on the heater core inlet liquid temperature in step S105 of FIG. 5 and the heater core inlet liquid temperature. FIG. [Figure 11] 4 is a diagram schematically showing the relationship between the opening degree of the bypass passage determined depending on the door position of the air mix door and the heater core inlet fluid temperature in the first embodiment. FIG. [Figure 12] 1 is a diagram showing a schematic configuration of an air conditioning unit and a liquid circuit included in an air conditioner of a first comparative example. [Figure 13] FIG. 10 is a diagram showing a change in liquid temperature in the liquid circuit, indicated by arrows, when the liquid heater is not in operation in the first comparative example. [Figure 14] FIG. 10 is a diagram showing a schematic configuration of an air conditioning unit and a liquid circuit provided in an air conditioner of a second comparative example. [Figure 15] This figure shows a schematic diagram of the liquid temperature change in the liquid circuit using arrows, taking the example of a case where the estimated liquid temperature at the liquid medium outlet of the heater core is less than the target value of the liquid temperature at the liquid medium inlet of the fuel cell, with (a) showing the second comparative example and (b) showing the first embodiment. [Figure 16]This figure shows a schematic diagram of the liquid temperature change in the liquid circuit using arrows in the second comparative example, where the estimated liquid temperature at the liquid medium outlet of the heater core is higher than the target liquid temperature at the liquid medium inlet of the fuel cell, with (a) showing the case where the air heater is not operating, and (b) showing the case where the air heater is operating. [Figure 17] 17A and 17B are diagrams showing a schematic diagram of the change in liquid temperature in the liquid circuit with arrows, taking as an example a case where the estimated value of the liquid temperature at the liquid medium outlet of the heater core is equal to or higher than the target value of the liquid temperature at the liquid medium inlet of the fuel cell. Fig. 17A is the same as Fig. 16A, and Fig. 17B is a diagram showing the first embodiment. [Figure 18] 10 is a flowchart showing a control process executed by a control unit provided in an air conditioner of a second embodiment, and corresponds to FIG. 5. [Figure 19] FIG. 20 is a diagram schematically showing a liquid temperature target value map used to determine the inlet liquid temperature target value in step S202 of FIG. [Figure 20] 19 is a diagram schematically showing a first liquid flow rate estimation map used to determine an upper set flow rate value in step S203 of FIG. 18. FIG. [Figure 21] FIG. 20 is a diagram schematically showing a second liquid flow rate estimation map used to determine a lower flow rate set value in step S204 of FIG. 18. [Figure 22] This is a diagram showing a schematic diagram of the relationship between the air heater output, the heating circuit lower limit flow rate, the upper flow rate set value, and the lower flow rate set value determined in step S205 of Figure 18 when the heating circuit lower limit flow rate is equal to or lower than the lower flow rate set value. [Figure 23] This is a diagram showing a schematic diagram of the relationship between the air heater output, the heating circuit lower limit flow rate, the upper flow rate set value, and the lower flow rate set value determined in step S205 of Figure 18 when the heating circuit lower limit flow rate is greater than the lower flow rate set value. [Figure 24] FIG. 10 is a cross-sectional view schematically showing a part of an air conditioning unit in a third embodiment. [Figure 25] 10 is a flowchart showing a control process executed by a control unit provided in an air conditioner of a third embodiment, and corresponds to FIG. 5. [Figure 26] FIG. 26 is a diagram schematically showing an air heater inlet temperature estimation map used to determine the air heater inlet target temperature in step S304 of FIG. 25, and corresponds to FIG. 7. [Figure 27] 26 is a diagram schematically showing a second inlet liquid temperature estimation map used to determine the inlet liquid temperature determination value in step S305 of FIG. 25, and corresponds to FIG. 9. FIG. [Figure 28] 26 is a diagram schematically showing the relationship between the number of PTC heaters to be operated, which is determined based on the heater core inlet liquid temperature in step S306 of FIG. 25, and the heater core inlet liquid temperature. FIG. [Figure 29] 10 is a diagram showing the switching state of a flow path switching valve of the liquid circuit of FIG. 2 when the liquid circuit is set to the semi-connected mode in another embodiment. FIG. [Figure 30] This is a diagram corresponding to Figure 28, which schematically shows the relationship between the number of PTC heaters to be operated, which is determined based on the heater core inlet liquid temperature in step S306 of Figure 25, and the heater core inlet liquid temperature in a modified example of the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, each embodiment will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

[0015] (First embodiment) The air conditioner 1 of this embodiment shown in Figures 1 and 2 is an air conditioner for a vehicle that is mounted on a vehicle and conditions the air inside the vehicle. For example, the vehicle on which the air conditioner 1 is mounted is a fuel cell vehicle that drives a traction motor with power supplied from a fuel cell 6. As shown in Figures 1 and 2, the air conditioner 1 of this embodiment includes an air conditioning unit 2, a liquid circuit 3, and a control unit 5.

[0016] 1 blows out into the vehicle interior air that has been temperature-controlled within the air conditioning unit 2. The air conditioning unit 2 is installed, for example, in an instrument panel located at the front of the vehicle interior.

[0017] As shown in FIG. 1, the air conditioning unit 2 includes an air conditioning case 21, an inside / outside air switching door 22, a blower 23, an evaporator 26, a heater core 27, an air heater 28, an air mix door 30, and the like.

[0018] 1, the air conditioning case 21 is made of a resin that has a certain degree of elasticity and excellent strength. An example of the resin that makes up the air conditioning case 21 is polypropylene. An air passage, i.e., a case ventilation path 24, through which air flows is formed inside the air conditioning case 21.

[0019] Furthermore, the air conditioning case 21 has an inside air inlet 241 and an outside air inlet 242 on the upstream side in the air flow direction of the case ventilation passage 24. The inside air inlet 241 is an air inlet for introducing inside air from a predetermined location inside the vehicle cabin to the case ventilation passage 24, and the outside air inlet 242 is an air inlet for introducing outside air from outside the vehicle to the case ventilation passage 24. The inside air is air inside the vehicle cabin, and the outside air is air outside the vehicle cabin.

[0020] Furthermore, the air conditioning case 21 has an air outlet section 25 on the downstream side of the case ventilation passage 24 in the air flow direction for blowing air from the case ventilation passage 24 to the front seat area in the vehicle interior. Although not shown, the air outlet section 25 has a plurality of outlet openings including a face outlet opening, a foot outlet opening, and a defroster outlet opening.

[0021] The face outlet blows conditioned air toward the upper bodies of occupants seated in the front seats. The foot outlet blows conditioned air toward the feet of the occupants. The defroster outlet blows conditioned air toward the front window of the vehicle. These outlets are selectively opened and closed by a door mechanism (not shown) controlled by the control unit 5.

[0022] Inside the air conditioning case 21, there are provided an inside / outside air switching door 22, a blower 23, an evaporator 26, a heater core 27, an air heater 28, an air mix door 30, etc. In other words, the air conditioning case 21 houses the inside / outside air switching door 22, the blower 23, the evaporator 26, the heater core 27, the air heater 28, the air mix door 30, etc.

[0023] The inside / outside air switching door 22 continuously adjusts the opening area of ​​the inside air inlet 241 and the opening area of ​​the outside air inlet 242. The inside / outside air switching door 22 is a door mechanism that rotates as indicated by arrow AD1 in FIG. 1 and is driven by an actuator such as a servo motor (not shown). The inside / outside air switching door 22 rotates so that the more one of the inside air inlet 241 and the outside air inlet 242 is opened, the more the other inlet is closed. This allows the inside / outside air switching door 22 to adjust the ratio of the amount of inside air and the amount of outside air introduced into the case ventilation passage 24. The door position of the inside / outside air switching door 22 is adjusted by the control unit 5. The inside / outside air switching door 22 is sometimes referred to as an inside / outside air switching damper.

[0024] The blower 23 is composed of a fan, which is an impeller (not shown), a motor that rotates and drives the fan, and the like. The blower 23 is also called a blower. When the fan rotates and drives together with the motor of the blower 23, an airflow is formed in the case ventilation passage 24. The rotation speed of the fan, which corresponds to the amount of air blown by the blower 23, is adjusted by the control unit 5.

[0025] In the case ventilation passage 24, the fan of the blower 23 is disposed downstream in the air flow direction relative to the inside air inlet 241 and the outside air inlet 242. As a result, air introduced into the case ventilation passage 24 from the inside air inlet 241 or the outside air inlet 242 flows through the case ventilation passage 24 and is ultimately blown out into the vehicle cabin from one of the multiple outlet openings. In the description of this embodiment, the air flowing through the case ventilation passage 24 and blown out into the vehicle cabin may be referred to as blown air. An arrow Ar in FIG. 1 indicates the flow direction of the blown air in the case ventilation passage 24.

[0026] The evaporator 26 is a heat exchanger for cooling the air flowing through the case ventilation passage 24. The evaporator 26 is disposed downstream in the air flow direction from the fan of the blower 23. Specifically, the evaporator 26 constitutes part of a refrigeration cycle circuit (not shown) through which a refrigerant circulates. The evaporator 26 exchanges heat between the air passing through the evaporator 26 and the refrigerant, evaporating the refrigerant and cooling the air through this heat exchange.

[0027] The case ventilation passage 24 has a hot air passage 243 and a bypass passage 244 that are provided downstream in the air flow direction relative to the evaporator 26 and upstream in the air flow direction relative to the air blow-out section 25. That is, the hot air passage 243 and the bypass passage 244 are formed inside the air conditioning case 21.

[0028] The hot air passage 243 and the bypass passage 244 are formed in parallel to each other. In the case ventilation passage 24, the air flowing out from the evaporator 26 flows into either or both of the hot air passage 243 and the bypass passage 244. Then, the air that has passed through either or both of the hot air passage 243 and the bypass passage 244 is blown out into the vehicle interior via the air blowing portion 25.

[0029] The heater core 27 and the air heater 28 are disposed in the hot air passage 243. Therefore, the bypass passage 244 functions as an air passage that allows the blown air to flow while bypassing the heater core 27 and the air heater 28. The blown air flowing out from the hot air passage 243 becomes hot air that has been heated by at least one of the heater core 27 and the air heater 28, and the blown air flowing out from the bypass passage 244 becomes cold air that has been cooled by the evaporator 26.

[0030] The heater core 27 is a heat exchanger for heating the blown air flowing through the hot air passage 243. As shown in Figures 1 and 2, the heater core 27 is provided in the liquid circuit 3, and has a liquid medium inlet 27a through which the liquid medium flows in and a liquid medium outlet 27b through which the liquid medium flows out.

[0031] Heater core 27 exchanges heat between the liquid medium flowing into heater core 27 from liquid medium inlet 27a and the blown air passing through heater core 27, causing the liquid medium to release heat through this heat exchange and heat the blown air. In liquid circuit 3, the liquid medium after exchanging heat with the blown air flows out from liquid medium outlet 41b. In liquid circuit 3, the liquid medium flowing out from fuel cell 6 may flow into heater core 27. In this case, heater core 27 uses the liquid medium flowing out from fuel cell 6 as a heat source to heat the blown air to be blown into the vehicle cabin.

[0032] Air heater 28 is an electric heater that heats air when electricity is applied. For example, a heating element such as an electric heating wire is used as the heat source of air heater 28, and the air heater output Pa, which is the output Pa of air heater 28 for heating the air, is adjusted by control unit 5.

[0033] The maximum air heater output Pam, which is the maximum value of the air heater output Pa within the allowed range, is determined, for example, from the allowable current of the air heater 28 itself and the upper limit of the power that can be consumed by the air heater 28 in the vehicle, and is treated as a constant in the control processing described below in Fig. 5. For example, the maximum air heater output Pam is the smaller of the air heater output Pa corresponding to the allowable current of the air heater 28 itself and the maximum value of the air heater output Pa determined in accordance with the power limit in the vehicle.

[0034] In addition, the air heater 28 is disposed in the hot air passage 243 downstream in the air flow direction from the heater core 27. Therefore, the air heater 28 further heats the blown air heated by the heater core 27.

[0035] The air mix door 30 is provided in the case ventilation passage 24 between the evaporator 26 and each of the hot air passage 243 and the bypass passage 244. The air mix door 30 is sometimes referred to as an air mix damper. The air mix door 30 continuously adjusts the opening degree of the hot air passage 243 and the bypass passage 244. The opening degree of the hot air passage 243 adjusted by the air mix door 30 is, more specifically, the opening degree of the inlet of the hot air passage 243, and the opening degree of the bypass passage 244 is, more specifically, the opening degree of the inlet of the bypass passage 244. The air mix door 30 is a door mechanism that rotates as indicated by arrow AD2 in FIG. 1 and is driven by an actuator such as a servo motor (not shown) controlled by the control unit 5.

[0036] Specifically, the air mix door 30 rotates so that the more one of the inlets of the warm air passage 243 and the bypass passage 244 is opened, the more the other inlet is closed. In this way, the air mix door 30 adjusts the ratio of the warm air volume Va, which is the volume of the blown air flowing through the warm air passage 243, to the bypass volume Va, which is the volume of the blown air flowing through the bypass passage 244. By adjusting this air volume ratio, the mixture ratio of the warm air flowing out from the warm air passage 243 and the cool air flowing out from the bypass passage 244 changes, so that the temperature of the blown air blown out from the air outlet portion 25 into the vehicle cabin can be adjusted by the air mix door 30. In the description of this embodiment, the term "air volume" refers to the mass flow rate of air unless otherwise specified.

[0037] The door position of the air mix door 30 is adjusted by the control unit 5. The door position where the air mix door 30 maximizes the opening of the hot air passage 243 and minimizes the opening of the bypass passage 244 is called the MAXHOT position. When the air mix door 30 is in the MAXHOT position, the ratio of the hot air flow rate Va to the total air flow rate of the hot air flow rate Va and the bypass air flow rate is maximized. For example, when the air mix door 30 is in the MAXHOT position, the bypass passage 244 is closed.

[0038] On the other hand, the door position where the air mix door 30 minimizes the opening of the hot air passage 243 and maximizes the opening of the bypass passage 244 is referred to as the MAXCOOL position. When the air mix door 30 is in the MAXCOOL position, the ratio of the bypass air volume to the total air volume of the hot air volume Va and the bypass air volume is maximized. For example, when the air mix door 30 is in the MAXCOOL position, the hot air passage 243 is closed. In the description of this embodiment, the door position of the air mix door 30 in the MAXHOT position may be referred to as "MAXHOT time." And the door position of the air mix door 30 in the MAXCOOL position may be referred to as "MAXCOOL time."

[0039] In the air conditioning unit 2 configured as described above, when the blower 23 is driven, air is introduced into the case ventilation passage 24 from one or both of the inside air inlet 241 and the outside air inlet 242. The introduced air then flows through the blower 23 and the evaporator 26 in this order, passes through the warm air passage 243 and one or both of the bypass passage 244, and is blown out from the air outlet portion 25 into the vehicle interior.

[0040] As shown in FIG. 2, the liquid circuit 3 is a liquid distribution circuit through which a liquid medium circulates. As the liquid medium circulates, the liquid circuit 3 cools the fuel cell 6, cools the air supplied to the fuel cell 6 through the intercooler 33, and heats the blown air passing through the heater core 27. As the liquid medium for the liquid circuit 3, for example, cooling water, which is a solution containing ethylene glycol, can be used. In this embodiment, the fuel cell 6 is the object to be cooled by the liquid medium of the liquid circuit 3. In FIG. 2, the arrows superimposed on the thick solid lines showing the distribution path of the liquid medium in the liquid circuit 3 indicate the flow direction of the liquid medium in that distribution path.

[0041] The liquid circuit 3 includes a first pump 31, a second pump 32, an intercooler 33, a flow path switching valve 34, a bypass liquid flow passage 38, a heater core 27, a liquid heater 40, a first radiator 41, a second radiator 42, a heat dissipation switching valve 43, piping connecting them, and multiple sensors 451, 452, 453, etc.

[0042] In the liquid circuit 3, the discharge port 31a of the first pump 31 is connected to the liquid medium inlet 33a of the intercooler 33 and the liquid medium inlet 6a of the fuel cell 6. Furthermore, the liquid medium outlet 6b of the fuel cell 6 and the liquid medium outlet 33b of the intercooler 33 are each connected to the first port 43a of the heat dissipation switching valve 43 via a bypass liquid flow passage 38. Furthermore, the liquid medium outlet 6b of the fuel cell 6 is also connected to the first port 34a of the flow path switching valve 34.

[0043] The second port 43b of the heat dissipation switching valve 43 is connected to the liquid medium inlet 41a of the first radiator 41 and the liquid medium inlet 42a of the second radiator 42. The third port 43c of the heat dissipation switching valve 43 is connected to the suction port 31b of the first pump 31 without passing through the first and second radiators 41, 42. The liquid medium outlet 41b of the first radiator 41 and the liquid medium outlet 42b of the second radiator 42 are connected to the suction port 31b of the first pump 31.

[0044] Furthermore, the third port 34c of the flow path switching valve 34 is connected to the intake port 32b of the second pump 32, the discharge port 32a of the second pump 32 is connected to the liquid medium inlet 40a of the liquid heater 40, and the liquid medium outlet 40b of the liquid heater 40 is connected to the liquid medium inlet 27a of the heater core 27. Furthermore, the liquid medium outlet 27b of the heater core 27 is connected to the second port 34b of the flow path switching valve 34 and the first port 43a of the heat dissipation switching valve 43, respectively.

[0045] The first pump 31 and the second pump 32 are electric pumps that pump the liquid medium, and the rotation speeds of the first pump 31 and the second pump 32 are controlled in accordance with control signals output from the control unit 5. The higher the rotation speed of the first pump 31, the larger the discharge flow rate of the first pump 31, and the higher the rotation speed Np of the second pump 32, the larger the discharge flow rate of the second pump 32.

[0046] The first pump 31 has a discharge port 31a and a suction port 31b, and discharges the liquid medium drawn in through the suction port 31b from the discharge port 31a. The second pump 32 has a discharge port 32a and a suction port 32b, and discharges the liquid medium drawn in through the suction port 32b from the discharge port 32a.

[0047] As described above, the discharge port 32a of the second pump 32 is connected to the liquid medium inlet 27a of the heater core 27 via the liquid heater 40, so that, for example, the greater the discharge flow rate of the second pump 32, the greater the heater core liquid flow rate Vw, which is the flow rate of the liquid medium circulating in the heater core 27. Therefore, the second pump 32 functions as a flow rate adjustment device that can increase or decrease the heater core liquid flow rate Vw.

[0048] The intercooler 33 has a liquid medium inlet 33a through which the liquid medium flows in and a liquid medium outlet 33b through which the liquid medium flows out. The intercooler 33 is a heat exchanger for cooling air, and cools the compressed air that is compressed by the compressor and supplied to the cell stack 6c of the fuel cell 6. That is, the intercooler 33 exchanges heat between the liquid medium that flows into the intercooler 33 from the liquid medium inlet 33a and the compressed air that is supplied to the cell stack 6c of the fuel cell 6, thereby cooling the compressed air. At this time, the liquid medium circulating inside the intercooler 33 is heated by the waste heat of the compressed air. After exchanging heat with the compressed air, the liquid medium flows out from the liquid medium outlet 33b.

[0049] The fuel cell 6 includes a battery stack 6c made up of multiple stacked battery cells that generate electricity using fuel for power generation and air supplied via an intercooler 33, and a heat exchanger 6d through which a liquid medium flows and exchanges heat between the liquid medium and the battery stack 6c. For example, the heat exchanger 6d of the fuel cell 6 is integral with the battery stack 6c, and is configured to cool the battery stack 6c while equalizing the temperature of the multiple battery cells included in the battery stack 6c through the flow of the liquid medium.

[0050] The fuel cell 6 has a liquid medium inlet 6a through which the liquid medium flows into the heat exchanger 6d and a liquid medium outlet 6b through which the liquid medium flows out of the heat exchanger 6d. Therefore, the liquid medium inlet 6a of the fuel cell 6 is, more specifically, the liquid medium inlet 6a of the heat exchanger 6d in the fuel cell 6, and the liquid medium outlet 6b of the fuel cell 6 is, more specifically, the liquid medium outlet 6b of the heat exchanger 6d in the fuel cell 6.

[0051] In the fuel cell 6, heat is exchanged between the liquid medium flowing from the liquid medium inlet 6a into the heat exchanger 6d and the cell stack 6c, thereby cooling the cell stack 6c, and the liquid medium flowing through the heat exchanger 6d is heated by waste heat from the cell stack 6c. After exchanging heat with the cell stack 6c, the liquid medium flows out from the liquid medium outlet 6b. As described above, the cell stack 6c is cooled by the liquid medium, but cooling the cell stack 6c also means cooling the fuel cell 6.

[0052] The first radiator 41 and the second radiator 42 are heat exchangers for dissipating heat, i.e., radiators, that exchange heat between the liquid medium and outside air and dissipate heat from the liquid medium. For example, the first radiator 41 is sometimes referred to as a main radiator, and the second radiator 42 is sometimes referred to as a sub-radiator. The first radiator 41 and the second radiator 42 are disposed on the front side of the vehicle so that they are exposed to outside air as a driving wind while the vehicle is running. Outside air is supplied to each of the first radiator 41 and the second radiator 42 by the vehicle running or by the operation of a blower (not shown).

[0053] The first radiator 41 has a liquid medium inlet 41a through which the liquid medium flows in and a liquid medium outlet 41b through which the liquid medium flows out. The first radiator 41 exchanges heat between the liquid medium that flows into the first radiator 41 from the liquid medium inlet 41a and the outside air, thereby cooling the liquid medium by dissipating heat from the liquid medium to the outside air. After exchanging heat with the outside air, the liquid medium flows out from the liquid medium outlet 41b.

[0054] The second radiator 42 has the same configuration as the first radiator 41. That is, the second radiator 42 has a liquid medium inlet 42a through which the liquid medium flows in and a liquid medium outlet 42b through which the liquid medium flows out. The second radiator 42 exchanges heat between the liquid medium that flows into the second radiator 42 from the liquid medium inlet 42a and the outside air, thereby cooling the liquid medium by dissipating heat from the liquid medium to the outside air. After exchanging heat with the outside air, the liquid medium flows out from the liquid medium outlet 42b.

[0055] The heat dissipation switching valve 43 has a first port 43a, a second port 43b, and a third port 43c. The first port 43a is an inlet port through which the liquid medium flows into the heat dissipation switching valve 43, and the second port 43b and the third port 43c are outlet ports through which the liquid medium flows out of the heat dissipation switching valve 43. For example, the heat dissipation switching valve 43 is a solenoid valve whose switching operation is controlled by the control unit 5.

[0056] The heat radiation switching valve 43 can be switched between a heat radiation switching state in which the first port 43a and the second port 43b are connected to each other while the third port 43c is fully closed, and a bypass switching state in which the first port 43a and the third port 43c are connected to each other while the second port 43b is fully closed. Note that fully closing a port of the switching valve means that the port is blocked and the flow of the liquid medium through that port is prevented.

[0057] For example, when the heat dissipation switching valve 43 is switched to the heat dissipation switching state, the liquid medium that flows into the first port 43a of the heat dissipation switching valve 43 dissipates heat in the first and second radiators 41 and 42 before being drawn into the suction port 31b of the first pump 31. In contrast, when the heat dissipation switching valve 43 is switched to the bypass switching state, the liquid medium that flows into the first port 43a of the heat dissipation switching valve 43 is drawn into the suction port 31b of the first pump 31 without passing through the first and second radiators 41 and 42. The control unit 5 adjusts the amount of heat dissipation from the liquid medium by appropriately switching the heat dissipation switching valve 43 between the heat dissipation switching state and the bypass switching state so that the fuel cell inlet liquid temperature, which is the temperature of the liquid medium at the liquid medium inlet 6a of the fuel cell 6, falls within a predetermined target liquid temperature range.

[0058] The flow path switching valve 34 has a first port 34a, a second port 34b, and a third port 34c. The first port 34a and the second port 34b are inlet ports through which the liquid medium flows into the flow path switching valve 34, and the third port 34c is an outlet port through which the liquid medium flows out of the flow path switching valve 34. For example, the flow path switching valve 34 is a solenoid valve whose switching operation is controlled by the control unit 5.

[0059] The flow path switching valve 34 is switched between a linked switching state shown in Fig. 3 and an independent switching state shown in Fig. 4. In the linked switching state, as shown in Fig. 3, the flow path switching valve 34 communicates between the first port 34a and the third port 34c while fully closing the second port 34b. In contrast, in the independent switching state, as shown in Fig. 4, the flow path switching valve 34 communicates between the second port 34b and the third port 34c while fully closing the first port 34a.

[0060] The flow path switching valve 34 switches the liquid circuit 3 between the linked mode and the independent mode in accordance with the switching between the linked switching state and the independent switching state. That is, as shown in Figures 2 and 3, when the flow path switching valve 34 is switched to the linked switching state, the liquid circuit 3 enters the linked mode. In the linked mode, a linked circuit configuration is established in which the liquid medium flows in this order through the first pump 31, fuel cell 6, flow path switching valve 34, second pump 32, liquid heater 40, heater core 27, and heat dissipation switching valve 43, and then flows to the radiators 41 and 42 before returning to the first pump 31.

[0061] When this interconnection circuit configuration is established, for example, fuel cell 6, liquid heater 40, heater core 27, and radiators 41 and 42 are connected in a circular fashion in liquid circuit 3 so that the liquid medium flows through fuel cell 6, liquid heater 40, heater core 27, and radiators 41 and 42 in that order, before returning to fuel cell 6. In this case, a portion of the liquid medium flowing out of fuel cell 6 passes through bypass liquid flow passage 38, bypassing liquid heater 40 and heater core 27 and flowing to radiators 41 and 42.

[0062] 2 and 4, when the flow path switching valve 34 is switched to the independent switching state, the liquid circuit 3 enters the independent mode. In the independent mode, a battery cooling circuit configuration 3a is established in which the liquid medium flows through the first pump 31, the fuel cell 6, and the heat dissipation switching valve 43 in this order, and then flows to the radiators 41 and 42 before returning to the first pump 31. In other words, in the battery cooling circuit configuration 3a established in the independent mode, the liquid medium circulates while flowing through the fuel cell 6. At the same time as the battery cooling circuit configuration 3a is established, a heating circuit configuration 3b is established as a separate circuit configuration from the battery cooling circuit configuration 3a in the independent mode, in which the liquid medium flows through the second pump 32, the liquid heater 40, the heater core 27, and the flow path switching valve 34 in this order, and then returns to the second pump 32. As a confirmation, in the interconnection circuit configuration and the battery cooling circuit configuration 3a, when the heat dissipation switching valve 43 is switched to the bypass switching state, the liquid medium flows from the heat dissipation switching valve 43 to the first pump 31 without passing through the radiators 41 and 42.

[0063] The circuit configuration as described above is established in both the linked mode and the independent mode of the liquid circuit 3, so for example, when the vehicle interior is heated using waste heat from the fuel cell 6, the liquid circuit 3 is switched to the linked mode and the first and second pumps 31 and 32 are operated. On the other hand, when the cooling of the fuel cell 6 and the heating of the vehicle interior are performed independently, the liquid circuit 3 is switched to the independent mode and the first and second pumps 31 and 32 are operated.

[0064] The liquid circuit 3 is also switched to the independent mode when the vehicle interior is not heated but the fuel cell 6 is cooled. In this case, however, the first pump 31 is operated but the second pump 32 is stopped.

[0065] Liquid heater 40 is an electric heater that heats the liquid medium when powered on. For example, a heating element such as an electric heating wire is used as the heat source of liquid heater 40, and the output of liquid heater 40 for heating the liquid medium is adjusted by control unit 5.

[0066] 2 , the liquid medium outlet 40b of the liquid heater 40 is connected to the liquid medium inlet 27a of the heater core 27. Therefore, when the liquid medium circulates in the linked mode of the liquid circuit 3, for example, the liquid heater 40 heats the liquid medium that flows out of the fuel cell 6 and into the heater core 27. When the liquid medium circulates in the independent mode of the liquid circuit 3, the liquid heater 40 heats the liquid medium that flows out from the liquid medium outlet 27b of the heater core 27 before flowing it into the liquid medium inlet 27a of the heater core 27. Therefore, in both the linked mode and the independent mode of the liquid circuit 3, the control unit 5 can adjust the heater core inlet liquid temperature TW by adjusting the output of the liquid heater 40. The heater core inlet liquid temperature TW is the temperature of the liquid medium at the liquid medium inlet 27a of the heater core 27.

[0067] As shown in Figures 1 and 2, the control unit 5 is an electronic control device configured with a semiconductor memory serving as a non-transitory tangible recording medium, a computer including a processor, and its peripheral circuits. The control unit 5 executes a computer program stored in the semiconductor memory. Execution of this computer program results in the execution of a method corresponding to the computer program. That is, the control unit 5 executes various control processes, such as the control process shown in the flowchart of Figure 5, described below, in accordance with the computer program.

[0068] The output side of the control unit 5 is connected to various devices including the components of the air conditioner 1. For example, the output side of the control unit 5 is connected to the inside / outside air switching door 22, the blower 23, the air heater 28, the air mix door 30, the first and second pumps 31 and 32, the flow path switching valve 34, the liquid heater 40, and the heat dissipation switching valve 43.

[0069] A plurality of sensors 451, 452, 453, etc. included in the air conditioner 1 are connected to the input side of the control unit 5. For example, a battery inlet liquid temperature sensor 451, a battery outlet liquid temperature sensor 452, and a heater core inlet liquid temperature sensor 453 are connected to the input side of the control unit 5.

[0070] The cell inlet liquid temperature sensor 451 is provided at the liquid medium inlet 6a of the fuel cell 6 and detects the fuel cell inlet liquid temperature. The cell outlet liquid temperature sensor 452 is provided at the liquid medium outlet 6b of the fuel cell 6 and detects the fuel cell outlet liquid temperature, which is the temperature of the liquid medium at the liquid medium outlet 6b of the fuel cell 6. The heater core inlet liquid temperature sensor 453 is provided at the liquid medium inlet 27a of the heater core 27 and detects the heater core inlet liquid temperature TW.

[0071] An operating device used for various input operations by the occupant is also connected to the input side of the control unit 5. The operating device is arranged, for example, near the instrument panel, and has various operating switches operated by the occupant, such as a temperature setting switch for adjusting the air conditioning temperature that indicates the desired temperature inside the vehicle cabin. An operating signal indicating information on the occupant's operation of the operating device is input to the control unit 5.

[0072] Fig. 5 is a flowchart showing the control process executed by the control unit 5. The control process of Fig. 5 is periodically and repeatedly executed during heating operation of the air conditioner 1. Since the control process of Fig. 5 is executed during heating operation, the first and second pumps 31, 32 are operating while the control process of Fig. 5 is being executed. Note that the control process of Fig. 5 can be executed whether the liquid circuit 3 is in linked mode or independent mode.

[0073] As shown in Fig. 5, first, in step S101, the control unit 5 calculates a target blow-out temperature TAO. This target blow-out temperature TAO is a target temperature value of the air blown into the vehicle cabin from the air outlet 25 of the air-conditioning case 21. For example, the control unit 5 calculates the target blow-out temperature TAO based on the air-conditioning temperature setting set by the passenger's operation, the room temperature in the vehicle cabin detected by various sensors, the outside air temperature, and the amount of solar radiation. For example, the target blow-out temperature TAO is set higher as the air-conditioning temperature setting is higher. After step S101, the process proceeds to step S102.

[0074] In step S102, the control unit 5 determines the inlet liquid temperature upper set value TWO based on the target blow-out temperature TAO determined in step S101. Specifically, the control unit 5 estimates the heater core inlet liquid temperature TW required to set the air heater outlet temperature to the target blow-out temperature TAO when the air heater 28 is turned off, and determines the estimated value of the heater core inlet liquid temperature TW as the inlet liquid temperature upper set value TW.

[0075] When the air heater 28 is turned off, this refers to the case where the air heater 28 does not heat the blown air, or in other words, the blown air passes through the air heater 28 without changing in temperature. The air heater outlet temperature is the temperature of the blown air flowing out from the air heater 28, or in other words, the temperature of the blown air at the air outlet 281 of the air heater 28.

[0076] For example, in this embodiment, the inlet liquid temperature upper set value TWO, which is an estimate of the heater core inlet liquid temperature TW, is determined based on the target blow-off temperature TAO from a preset first inlet liquid temperature estimation map Mtwo shown in FIG. 6. This first inlet liquid temperature estimation map Mtwo represents a relationship between the heater core inlet liquid temperature TW and the target blow-off temperature TAO, which is experimentally obtained in advance, when the air heater 28 is turned off and the air heater outlet temperature becomes the target blow-off temperature TAO. The first inlet liquid temperature estimation map Mtwo is experimentally obtained in advance on the assumption that the temperature is MAXHOT, and is stored in the control unit 5. In the first inlet liquid temperature estimation map Mtwo, the inlet liquid temperature upper set value TWO, which is an estimate of the heater core inlet liquid temperature TW, increases as the target blow-off temperature TAO increases. Step S102 in FIG. 5 is followed by step S103.

[0077] In step S103, the control unit 5 determines the air heater inlet target temperature THOin based on the hot air flow rate Va at MAXHOT and the target blown air temperature TAO determined in step S101. Specifically, the control unit 5 estimates the air heater inlet temperature required to make the air heater outlet temperature equal to the target blown air temperature TAO under a predetermined heating operating condition in which the air heater 28 heats the blown air. The control unit 5 then determines the estimated value of the air heater inlet temperature as the air heater inlet target temperature THOin. Specifically, the predetermined heating operating condition is an operating condition in which the air heater 28 heats the blown air at the air heater maximum output Pam.

[0078] The air heater inlet temperature is the temperature of the blown air flowing into the air heater 28, in other words, the temperature of the blown air at the air inlet 282 of the air heater 28, and is also the temperature of the blown air at the air outlet 271 of the heater core 27. Therefore, the air heater inlet target temperature THOin is not only the target value of the air heater inlet temperature, but also the target temperature value of the blown air at the air outlet 271 of the heater core 27. Furthermore, the hot air flow rate Va at MAXHOT may be detected by an air flow sensor or the like, but in this embodiment it is estimated from the rotation speed of the blower 23 or the like.

[0079] For example, in this embodiment, the air heater inlet target temperature THOin, which is an estimated value of the air heater inlet temperature, is determined based on the hot air flow rate Va and the target blown-out temperature TAO at MAXHOT from the preset air heater inlet temperature estimation map Mtho shown in Fig. 7. That is, the input parameters of the air heater inlet temperature estimation map Mtho are the hot air flow rate Va and the target blown-out temperature TAO at MAXHOT.

[0080] This air heater inlet temperature estimation map Mtho represents the relationship between the air heater inlet temperature, which has been experimentally obtained in advance, and each input parameter when the air heater outlet temperature becomes the target blown-out temperature TAO while the air heater 28 is in the above-mentioned predetermined heating operation state. The air heater inlet temperature estimation map Mtho has been experimentally obtained in advance assuming MAXHOT, and is stored in the control unit 5. In the air heater inlet temperature estimation map Mtho, the higher the target blown-out temperature TAO and the larger the hot air flow rate Va at MAXHOT, the higher the air heater inlet target temperature THOin, which is the estimated value of the air heater inlet temperature. After step S103 in FIG. 5, the process proceeds to step S104.

[0081] In step S104, the control unit 5 first obtains the heater core fluid flow rate Vw to determine the inlet fluid temperature lower set value TWOb. The heater core fluid flow rate Vw may be detected by a sensor, but in this embodiment, it is estimated from the fluid flow rate map Mvw of FIG. 8 based on the rotation speed Np of the second pump 32 and the heater core inlet fluid temperature TW detected by the heater core inlet fluid temperature sensor 453. Therefore, strictly speaking, the heater core fluid flow rate Vw obtained in step S104 is an estimated value of the heater core fluid flow rate Vw. The fluid flow rate map Mvw represents the relationship between the rotation speed Np of the second pump 32, the heater core inlet fluid temperature TW, and the heater core fluid flow rate Vw, which has been experimentally obtained in advance, and is stored in the control unit 5.

[0082] After determining the heater core liquid flow rate Vw, the control unit 5 next determines the inlet liquid temperature lower set value TWOb based on the heater core liquid flow rate Vw, the heater core inlet air temperature TAhcin, the hot air flow rate Va at MAXHOT, and the air heater inlet target temperature THOin. Specifically, the control unit 5 estimates the heater core inlet liquid temperature TW required to set the air heater outlet temperature to the target blown air temperature TAO when the air heater 28 is in the predetermined heating operation state. The control unit 5 then determines the estimated heater core inlet liquid temperature TW as the inlet liquid temperature lower set value TWOb. The heater core inlet air temperature TAhcin is the temperature of the blown air at the air inlet 272 of the heater core 27 and is detected, for example, by a temperature sensor.

[0083] For example, in this embodiment, the inlet liquid temperature lower set value TWOb is determined based on the heater core liquid flow rate Vw, the heater core inlet air temperature TAhcin, the hot air flow rate Va at MAXHOT, and the air heater inlet target temperature THOin from the preset second inlet liquid temperature estimation map Mtwob in Fig. 9. That is, the input parameters of the second inlet liquid temperature estimation map Mtwob are the heater core liquid flow rate Vw, the heater core inlet air temperature TAhcin, the hot air flow rate Va at MAXHOT, and the air heater inlet target temperature THOin.

[0084] The second inlet liquid temperature estimation map Mtwob represents the relationship between the heater core inlet liquid temperature TW and each input parameter, which is experimentally obtained in advance, when the air heater outlet temperature becomes the target blowout temperature TAO while the air heater 28 is in the predetermined heating operation state. The second inlet liquid temperature estimation map Mtwob is experimentally obtained in advance on the premise of MAXHOT, and is stored in the control unit 5.

[0085] In the second inlet fluid temperature estimation map Mtwob, the lower the heater core fluid flow rate Vw, the lower the heater core inlet air temperature TAhcin, and the larger the hot air flow rate Va at MAXHOT, the higher the inlet fluid temperature lower set value TWOb, which is the estimated value of the heater core inlet fluid temperature TW. The higher the air heater inlet target temperature THOin, the higher the inlet fluid temperature lower set value TWOb. After step S104 in FIG. 5, the process proceeds to step S105.

[0086] In step S105, the control unit 5 obtains the heater core inlet liquid temperature TW detected by the heater core inlet liquid temperature sensor 453. Then, the control unit 5 operates the air heater 28 in accordance with the heater core inlet liquid temperature TW, the inlet liquid temperature upper set value TWO, and the inlet liquid temperature lower set value TWOb so as to converge the air heater outlet temperature to the target blow-out temperature TAO.

[0087] Specifically, the control unit 5 determines the air heater output Pa based on the heater core inlet liquid temperature TW in accordance with the correspondence shown in Fig. 10, and operates the air heater 28 at the determined air heater output Pa. In this way, the control unit 5 causes the air heater outlet temperature to converge to the target blown-out temperature TAO.

[0088] 10, the control unit 5 turns off the air heater 28 when the heater core inlet liquid temperature TW is equal to or higher than the inlet liquid temperature upper set value TWO. In other words, in this case, the control unit 5 sets the air heater output Pa to zero. In contrast, when the heater core inlet liquid temperature TW is lower than the inlet liquid temperature upper set value TWO, the control unit 5 increases the air heater output Pa as the heater core inlet liquid temperature TW decreases.

[0089] More specifically, when the heater core inlet liquid temperature TW is equal to or lower than the inlet liquid temperature lower set value TWOb, the control unit 5 operates the air heater 28 at the air heater maximum output Pam. When the heater core inlet liquid temperature TW is higher than the inlet liquid temperature lower set value TWOb and within a temperature range lower than the inlet liquid temperature upper set value TWO, the control unit 5 operates the air heater 28 as follows. That is, when the heater core inlet liquid temperature TW is within the temperature range, the control unit 5 operates the air heater 28 at an intermediate air heater output Pa that is lower than the air heater maximum output Pam and greater than zero, so as to converge the air heater outlet temperature to the target blown air temperature TAO. For example, in this case, the air heater output Pa may be adjusted by feedback control. Alternatively, in this case, the air heater output Pa may be determined according to an empirical formula or map that is experimentally established in advance so as to interpolate the air heater output Pa between zero and the air heater maximum output Pam in accordance with the heater core inlet liquid temperature TW. After step S105 in FIG. 5, the process proceeds to step S106.

[0090] In step S106, the control unit 5 determines the output of the liquid heater 40, setting the target temperature value of the liquid medium when heating the liquid medium with the liquid heater 40 as the inlet liquid temperature lower set value TWOb, and operates the liquid heater 40 at the determined output.

[0091] For example, when the temperature of the liquid medium flowing into the liquid heater 40 (i.e., the liquid temperature) is less than the inlet liquid temperature lower set value TWOb, the control unit 5 causes the liquid heater 40 to heat the liquid medium so that the heater core inlet liquid temperature TW becomes the inlet liquid temperature lower set value TWOb. In other words, the temperature of the liquid medium flowing into the liquid heater 40 is the temperature of the liquid medium at the liquid medium inlet 40a of the liquid heater 40. The temperature of the liquid medium flowing into the liquid heater 40 may be detected by a sensor (not shown), or, if the liquid circuit 3 is in the linked mode, may be considered to be the same temperature as the fuel cell outlet liquid temperature detected by the cell outlet liquid temperature sensor 452.

[0092] Furthermore, when the temperature of the liquid medium flowing into liquid heater 40 is equal to or higher than inlet liquid temperature lower setpoint TWOb, control unit 5 turns off liquid heater 40. Turning off liquid heater 40 means, in other words, setting the output of liquid heater 40 to zero. Therefore, when liquid heater 40 is off, liquid heater 40 does not heat the liquid medium. After step S106 in FIG. 5, the process returns to step S101.

[0093] 5 constitutes a functional unit that realizes each function, and the control unit 5 has that functional unit. This also applies to the flowcharts described later.

[0094] As shown in Fig. 5, the output control of the air heater 28 and the liquid heater 40 is executed, and in parallel with this, the operation control of the air mix door 30 is also executed during the heating operation of the air conditioner 1. Specifically, the control unit 5 controls the door position of the air mix door 30 based on the inlet liquid temperature upper set value TWO and the heater core inlet liquid temperature TW detected by the heater core inlet liquid temperature sensor 453 so as to follow the correspondence shown in Fig. 11. For example, the control unit 5 periodically updates the door position of the air mix door 30 at the same timing as the execution timing of step S105 or S106 in Fig. 5.

[0095] 11, when the heater core inlet fluid temperature TW is equal to or lower than the upper inlet fluid temperature set value TWO, the door position of the air mix door 30 is set to the MAXHOT position. When the door position of the air mix door 30 is set to the MAXHOT position, the opening degree of the bypass passage 244 becomes minimum, for example, zero.

[0096] On the other hand, when the heater core inlet liquid temperature TW exceeds the upper inlet liquid temperature set value TWO, the air mix door 30 is controlled to cause the outlet air temperature, which is the temperature of the air blown into the vehicle cabin from the air outlet port 25 of the air conditioning case 21, to converge to the target outlet temperature TAO. In this case, the higher the heater core inlet liquid temperature TW, the smaller the ratio of the hot air flow rate Va to the total air flow rate of the hot air flow rate Va and the bypass air flow rate. In other words, the door position of the air mix door 30 is controlled so that the higher the heater core inlet liquid temperature TW, the greater the opening of the bypass passage 244. The door position at this time may be determined by feedback control or may be determined according to an empirical formula or map previously established through experiments.

[0097] As described above, according to this embodiment, as shown in Fig. 5, the control unit 5 determines, as the inlet liquid temperature upper set value TWO, an estimated value of the heater core inlet liquid temperature TW required to set the air heater outlet temperature to the target blow-out temperature TAO when the air heater 28 is turned off. The control unit 5 also determines, as the inlet liquid temperature lower set value TWOb, an estimated value of the heater core inlet liquid temperature TW required to set the air heater outlet temperature to the target blow-out temperature TAO when the air heater 28 is in the predetermined heating operation state. Then, as shown in Fig. 10, the control unit 5 operates the air heater 28 in accordance with the heater core inlet liquid temperature TW, the inlet liquid temperature upper set value TWO, and the inlet liquid temperature lower set value TWOb so as to converge the air heater outlet temperature to the target blow-out temperature TAO.

[0098] This prevents the air heater 28 from heating the blown air so that the air heater outlet temperature exceeds the target blown air temperature TAO, thereby preventing the air heater 28 from excessively heating the blown air.

[0099] To explain the effects of the present embodiment, a first comparative example will be considered, in which control similar to that disclosed in Patent Document 1 is executed. The air conditioning unit 2 included in the air conditioning device of the first comparative example is the same as that of the present embodiment, but for simplicity of explanation, the liquid circuit 80 included in the air conditioning device of the first comparative example is configured as shown in FIG. 12. The liquid circuit 80 in FIG. 12 is formed in a ring shape so that the liquid medium flows through the fuel cell 6, liquid heater 40, heater core 27, and radiator 41 in this order before returning to the fuel cell 6. The liquid medium is circulated in the liquid circuit 80 by a pump (not shown). The arrows with dotted hatching in FIG. 12 indicate the flow of blown air.

[0100] In the first comparative example, when the liquid heater 40 is not operating, the temperature of the liquid medium (in other words, the liquid temperature) changes in each component of the liquid circuit 80, for example, as shown in FIG. 13. In FIG. 13, arrow A1a indicates the change in liquid temperature in the fuel cell 6, arrow A1b indicates the change in liquid temperature in the heater core 27, and arrow A1c indicates the change in liquid temperature in the radiator 41. The base ends of the arrows A1a, A1b, and A1c indicate the liquid temperature at the inlet of each component, and the tips of the arrows A1a, A1b, and A1c indicate the liquid temperature at the outlet of each component. This is also true in later figures that show liquid temperatures similar to FIG. 13.

[0101] In the first comparative example, the air heater 28 is operated according to the same control as that of Patent Document 1 as described above, and therefore, for example, when the estimated value of the liquid temperature at the liquid medium outlet 27b of the heater core 27 is equal to or higher than the target value of the liquid temperature at the liquid medium inlet 6a of the fuel cell 6, the air heater 28 is operated. Specifically, the air heater 28 is operated at an air heater output Pa that is set based on the estimated value of the liquid temperature at the liquid medium outlet 27b of the heater core 27. Therefore, there is a case where the blown air heated by the air heater 28 is cooled to the target blown air temperature TAO by the blown air that has passed through the bypass passage 244 and then blown into the vehicle compartment.

[0102] In contrast, in this embodiment, the air heater output Pa is determined based on the heater core inlet liquid temperature TW in accordance with the correspondence shown in FIG. 10. Therefore, even if the air heater output Pa becomes, for example, the maximum air heater output Pam in accordance with the correspondence shown in FIG. 10, the air heater outlet temperature is unlikely to exceed the target blowout temperature TAO. For example, regardless of whether the estimated liquid temperature at the liquid medium outlet 27b of the heater core 27 is equal to or greater than the target liquid temperature at the liquid medium inlet 6a of the fuel cell 6, the air heater 28 is turned off if the heater core inlet liquid temperature TW is equal to or greater than the upper inlet liquid temperature setpoint TWO. This prevents the bypass passage 244 from being opened larger than the MAXHOT setting while the blown air is heated by the air heater 28, thereby reducing unnecessary power consumption by the air heater 28. This effect remains the same even if the liquid circuit 3 of FIG. 2 in this embodiment is replaced with the liquid circuit 80 of FIG. 12.

[0103] (1) Furthermore, according to this embodiment, the predetermined heating operation state is an operation state in which the air heater 28 heats the blown air at the maximum air heater output Pam. The maximum air heater output Pam is the maximum value of the air heater output Pa within the allowable range. This maximizes the effect of reducing wasteful power consumption by the air heater 28. Furthermore, it is possible to maximize the ability of the air heater 28 to heat the blown air, and to converge the air heater outlet temperature to the target blown air temperature TAO while minimizing the need to increase the heater core inlet liquid temperature TW. That is, in the linked mode of the liquid circuit 3, more of the waste heat from the fuel cell 6 can be used to heat the vehicle interior.

[0104] (2) Furthermore, according to this embodiment, as shown in Fig. 10, the control unit 5 turns off the air heater 28 when the heater core inlet liquid temperature TW is equal to or higher than the inlet liquid temperature upper set value TWO. When the heater core inlet liquid temperature TW is lower than the inlet liquid temperature upper set value TWO, the control unit 5 increases the air heater output Pa as the heater core inlet liquid temperature TW decreases. Therefore, the air heater output Pa can be easily determined based on the heater core inlet liquid temperature TW so as to reduce unnecessary power consumption of the air heater 28.

[0105] (3) Furthermore, according to this embodiment, as shown in Figure 2, the liquid heater 40 is provided in the liquid circuit 3 and heats the liquid medium that flows out of the fuel cell 6 and into the heater core 27. Therefore, by heating the liquid medium with the liquid heater 40, rapid heating and heating in the independent mode of the liquid circuit 3 are possible. Furthermore, since it is no longer necessary to adjust the heat generation of the fuel cell 6 in order to raise the heater core inlet liquid temperature TW, damage to the fuel cell 6 that would be caused by adjusting the heat generation of the fuel cell 6 can be reduced.

[0106] (4) Furthermore, according to this embodiment, for example, when the temperature of the liquid medium flowing into the liquid heater 40 is less than the inlet liquid temperature lower set value TWOb, the control unit 5 causes the liquid heater 40 to heat the liquid medium so that the heater core inlet liquid temperature TW becomes the inlet liquid temperature lower set value TWOb. Therefore, compared to when the liquid medium is heated by the liquid heater 40 so that the heater core inlet liquid temperature TW becomes the heater core inlet liquid temperature upper set value TWO, for example, it is possible to lower the liquid temperature at the liquid medium outlet 27b of the heater core 27 and promote waste heat utilization.

[0107] Here, a second comparative example will be considered to explain the effects of the above-described embodiment. The second comparative example differs from the first comparative example in that the liquid circuit 80 is replaced with the configuration shown in FIG. 14, but is otherwise the same as the first comparative example. The liquid circuit 80 of FIG. 14 differs from the liquid circuit 80 of FIG. 12 in that it includes a bypass liquid flow passage 38, but is otherwise the same as the liquid circuit 80 of FIG. 12. The bypass liquid flow passage 38 of the liquid circuit 80 of FIG. 14 connects the flow path between the liquid medium outlet 6b of the fuel cell 6 and the liquid medium inlet 40a of the liquid heater 40 to the flow path between the liquid medium outlet 27b of the heater core 27 and the liquid medium inlet 41a of the first radiator 41.

[0108] In the second comparative example, for example, if the estimated value of the liquid temperature at liquid medium outlet 27b of heater core 27 is lower than the target value of the liquid temperature at liquid medium inlet 6a of fuel cell 6, the temperature of the liquid medium, i.e., the liquid temperature, changes as shown in Figure 15(a). In Figures 15(a) and 15(b), arrow A2a indicates the change in liquid temperature at fuel cell 6, arrow A2b indicates the change in liquid temperature at liquid heater 40, and arrow A2c indicates the change in liquid temperature at radiator 41. For ease of explanation, Figures 15(a) and 15(b), Figures 16(a) and 16(b), and Figures 17(a) and 17(b) show an example in which the liquid temperature at liquid medium outlet 6b of fuel cell 6 is the inlet liquid temperature lower set value TWOb.

[0109] In the second comparative example, when the estimated value of the liquid temperature at liquid medium outlet 27b of heater core 27 is lower than the target value of the liquid temperature at liquid medium inlet 6a of fuel cell 6, air heater 28 does not operate. Therefore, liquid heater 40 needs to heat the liquid medium flowing to heater core 27 so that the air heater outlet temperature becomes the target blowout temperature TAO. As a result, as shown in FIG. 15(a), energy loss occurs due to the liquid medium heated by liquid heater 40 being cooled by radiator 41.

[0110] In contrast to this, in this embodiment, the target value of the heater core inlet liquid temperature TW when the liquid heater 40 heats the liquid medium is the inlet liquid temperature lower set value TWOb, so the control unit 5 turns off the liquid heater 40, as shown in Fig. 15(b). Then, the insufficient heating amount ΔH of the blown air by the heater core 27 relative to the target blown air temperature TAO is compensated for by the heating operation of the air heater 28.

[0111] As a result, in this embodiment, when the estimated value of the liquid temperature at the liquid medium outlet 27b of the heater core 27 is lower than the target value of the liquid temperature at the liquid medium inlet 6a of the fuel cell 6 during the coupled mode of the liquid circuit 3, the amount of heat dissipated by the radiator 41 is reduced compared to the second comparative example. Furthermore, since the target value of the heater core inlet liquid temperature TW is lower compared to the second comparative example, more waste heat from the fuel cell 6 can be used to heat the vehicle interior during the coupled mode of the liquid circuit 3, thereby reducing power consumption. This effect remains the same even if the liquid circuit 3 of FIG. 2 in this embodiment is replaced with the liquid circuit 80 of FIG. 14. Note that while FIG. 15(b) and FIG. 17(b) described below do not show heat dissipation by the radiator 41, this is merely an example, and heat dissipation by the radiator 41 is not always zero.

[0112] Next, a second comparative example will be described using as an example a case where the estimated value of the liquid temperature at the liquid medium outlet 27b of the heater core 27 is equal to or higher than the target value of the liquid temperature at the liquid medium inlet 6a of the fuel cell 6. In this case, in the second comparative example, the air heater 28 operates to heat the blown air. Therefore, if the air heater 28 were not operating, the liquid temperature would change as shown in FIG. 16(a). However, as the air heater 28 operates, the target value of the heater core inlet liquid temperature TW decreases as shown by arrow B1 in FIG. 16(b). As a result, the liquid temperature changes as shown in FIG. 16(b), and the amount of heat radiation in the radiator 41 decreases by the amount indicated by arrow B2.

[0113] However, in the second comparative example, air heater 28 does not operate when the estimated value of the liquid temperature at liquid medium outlet 27b of heater core 27 is less than the target value of the liquid temperature at liquid medium inlet 6a of fuel cell 6. Therefore, even when the estimated value of the liquid temperature at liquid medium outlet 27b of heater core 27 is equal to or greater than the target value of the liquid temperature at liquid medium inlet 6a of fuel cell 6, energy loss occurs due to the liquid heated by liquid heater 40 being cooled by radiator 41.

[0114] In contrast, in this embodiment, the target value of the heater core inlet liquid temperature TW is the lower inlet liquid temperature setpoint TWOb as described above. Therefore, as shown by arrow B3 in FIG. 17(b), the target value of the heater core inlet liquid temperature TW is lower than that in the second comparative example, and the liquid heater 40 is turned off. The insufficient heating amount ΔH of the blown air by the heater core 27 relative to the target outlet temperature TAO is compensated for by the heating operation of the air heater 28. Therefore, in the case shown in FIG. 17(b), more waste heat from the fuel cell 6 can be used to heat the vehicle interior when the liquid circuit 3 is in the linked mode than in the second comparative example, thereby reducing power consumption. This effect remains the same even if the liquid circuit 3 of FIG. 2 in this embodiment is replaced with the liquid circuit 80 of FIG. 14. Note that FIG. 17(a) is the same as FIG. 16(a).

[0115] (5) According to this embodiment, as shown in FIG. 2 , the flow path switching valve 34 switches the liquid circuit 3 between a linked mode and an independent mode. In the linked mode, a linked circuit configuration is established in which the liquid medium flows through the first pump 31, the fuel cell 6, the flow path switching valve 34, the second pump 32, the liquid heater 40, the heater core 27, and the heat dissipation switching valve 43 in this order, then flows to the radiators 41 and 42, and then returns to the first pump 31. In the independent mode, a battery cooling circuit configuration 3a is established in which the liquid medium flows through the first pump 31, the fuel cell 6, and the heat dissipation switching valve 43 in this order, then flows to the radiators 41 and 42, and then returns to the first pump 31. At the same time, in the independent mode, a heating circuit configuration 3b is also established in which the liquid medium flows through the second pump 32, the liquid heater 40, the heater core 27, and the flow path switching valve 34 in this order, then returns to the second pump 32.

[0116] Therefore, by setting the liquid circuit 3 to linked mode, the waste heat from the fuel cell 6 can be used to heat the vehicle interior, and by setting the liquid circuit 3 to independent mode, it is possible to promote warming up of the fuel cell 6.

[0117] (6) Furthermore, according to this embodiment, the liquid circuit 3 has a bypass liquid flow passage 38. When the liquid circuit 3 is in the linked mode, the bypass liquid flow passage 38 causes a portion of the liquid medium flowing out of the fuel cell 6 to bypass the heater core 27 and flow to the radiators 41, 42. Therefore, when the liquid circuit 3 is in the linked mode, it is possible to reduce pressure loss of the liquid medium compared to when, for example, the entire amount of the liquid medium flowing out of the fuel cell 6 flows to the heater core 27.

[0118] (7) Furthermore, according to this embodiment, the air mix door 30 adjusts the ratio of the hot air volume Va flowing through the hot air passage 243 to the bypass air volume flowing through the bypass passage 244. Therefore, it is possible to adjust the temperature of the air blown from the air conditioning unit 2 into the vehicle cabin.

[0119] (8) According to this embodiment, the control unit 5 controls the air mix door 30 as shown in FIG. 11 . That is, when the heater core inlet liquid temperature TW is equal to or lower than the inlet liquid temperature upper set value TWO, the control unit 5 controls the air mix door 30 so that the ratio of the hot air flow rate Va to the total air flow rate of the hot air flow rate Va and the bypass air flow rate is maximized. When the heater core inlet liquid temperature TW exceeds the inlet liquid temperature upper set value TWO, the control unit 5 controls the air mix door 30 so that the ratio of the hot air flow rate Va to the total air flow rate decreases as the heater core inlet liquid temperature TW increases. Therefore, it is possible to adjust the temperature of the air blown from the air conditioning unit 2 into the vehicle cabin to an appropriate temperature while preventing the air from being excessively heated by the air heater 28.

[0120] (Second embodiment) Next, a second embodiment will be described. In this embodiment, differences from the first embodiment will be mainly described. Furthermore, parts that are the same as or equivalent to the first embodiment will be omitted or simplified. This also applies to the following embodiments.

[0121] In this embodiment, the control unit 5 does not execute the control process shown in the flowchart of Fig. 5, but instead executes the control process shown in the flowchart of Fig. 18. In this respect, this embodiment differs from the first embodiment. Note that, of the multiple steps in Fig. 18, steps with the same content as in Fig. 5 are assigned the same reference numerals as in Fig. 5, and descriptions of steps with the same content as in Fig. 5 will be omitted as appropriate.

[0122] As shown in Fig. 18, after step S101, the process proceeds to step S202. In step S202, the control unit 5 determines an inlet liquid temperature target value TWOa, which is a target value for the heater core inlet liquid temperature TW, based on the target blow-out temperature TAO determined in step S101. This inlet liquid temperature target value TWOa is used, for example, when activating the liquid heater 40. This inlet liquid temperature target value TWOa is determined so that the air heater outlet temperature becomes the target blow-out temperature TAO by activating the air heater 28 and the liquid heater 40.

[0123] For example, in this embodiment, the inlet liquid temperature target value TWOa is determined based on the target outlet temperature TAO from a liquid temperature target value map Mtwoa in Fig. 19 that was experimentally set in advance assuming MAXHOT. In the liquid temperature target value map Mtwoa, the higher the target outlet temperature TAO, the higher the inlet liquid temperature target value TWOa. After step S202 in Fig. 18, the process proceeds to step S203.

[0124] In step S203, the control unit 5 determines the upper flow rate set value VWO based on the target blow-out temperature TAO determined in step S101. Specifically, the control unit 5 estimates the heater core liquid flow rate Vw required to set the air heater outlet temperature to the target blow-out temperature TAO when the air heater 28 is turned off, and determines the estimated value of the heater core liquid flow rate Vw as the upper flow rate set value VWO.

[0125] For example, in this embodiment, the upper flow rate set value VWO, which is an estimated value of the heater core fluid flow rate Vw, is determined based on the target blow-out temperature TAO from a preset first fluid flow rate estimation map Mvwo shown in Fig. 20. This first fluid flow rate estimation map Mvwo represents a relationship between the heater core fluid flow rate Vw and the target blow-out temperature TAO, which is experimentally obtained in advance, when the air heater outlet temperature becomes the target blow-out temperature TAO when the air heater 28 is turned off. The first fluid flow rate estimation map Mvwo is experimentally obtained in advance on the assumption that the temperature is MAXHOT, and is stored in the control unit 5. In the first fluid flow rate estimation map Mvwo, the higher the target blow-out temperature TAO, the larger the upper flow rate set value VWO, which is an estimated value of the heater core fluid flow rate Vw.

[0126] The first fluid flow rate estimation map Mvwo is set so that the upper flow rate set value VWO is always equal to or greater than the heating circuit lower limit flow rate Vwmin, which is the lower limit Vwmin of the heater core fluid flow rate Vw. This heating circuit lower limit flow rate Vwmin is determined from the minimum discharge flow rate of the second pump 32 or the allowable limit of the heater core fluid flow rate Vw required to obtain an appropriate temperature distribution in the heater core 27, and is treated as a constant in the control process of Fig. 18. After step S203 in Fig. 18, the process proceeds to step S103, and after step S103, the process proceeds to step S204.

[0127] In step S204, the control unit 5 determines the lower flow rate set value VWOb based on the inlet liquid temperature target value TWOa, the heater core inlet air temperature TAhcin, the hot air flow rate Va at MAXHOT, and the air heater inlet target temperature THOin. Specifically, the control unit 5 estimates the heater core liquid flow rate Vw required to set the air heater outlet temperature to the target blown air temperature TAO when the air heater 28 is in the predetermined heating operating condition. The control unit 5 then determines the estimated value of the heater core liquid flow rate Vw as the lower flow rate set value VWOb. In this embodiment, as in the first embodiment, the predetermined heating operating condition is an operating condition in which the air heater 28 heats the blown air at the air heater maximum output Pam.

[0128] For example, in this embodiment, the inlet liquid temperature lower set value TWOb is determined based on the inlet liquid temperature target value TWOa, the heater core inlet air temperature TAhcin, the hot air flow rate Va at MAXHOT, and the air heater inlet target temperature THOin from the preset second liquid flow rate estimation map Mvwob in Fig. 21. That is, the input parameters of the second liquid flow rate estimation map Mvwob are the inlet liquid temperature target value TWOa, the heater core inlet air temperature TAhcin, the hot air flow rate Va at MAXHOT, and the air heater inlet target temperature THOin.

[0129] The second liquid flow rate estimation map Mvwob represents the relationship between the heater core liquid flow rate Vw and each input parameter obtained through experiments in advance when the air heater outlet temperature is the target blowout temperature TAO while the air heater 28 is in the above-mentioned predetermined heating operation state. The second liquid flow rate estimation map Mvwob is obtained through experiments in advance on the assumption that the heater core inlet liquid temperature TW is the inlet liquid temperature target value TWOa and is at MAXHOT, and is stored in the control unit 5.

[0130] In the second fluid flow rate estimation map Mvwob, the lower the inlet fluid temperature target value TWOa, the lower the heater core inlet air temperature TAhcin, and the larger the hot air flow rate Va at MAXHOT, the larger the flow rate lower set value VWOb, which is the estimated value of the heater core fluid flow rate Vw. The higher the air heater inlet target temperature THOin, the larger the flow rate lower set value VWOb. After step S204 in FIG. 18, the process proceeds to step S205.

[0131] In step S205, the control unit 5 sets the larger of the heating circuit lower limit flow rate Vwmin and the lower flow rate set value VWOb as the flow rate target value. The control unit 5 then controls the second pump 32 to circulate the liquid medium so that the heater core liquid flow rate Vw converges to the flow rate target value. Just to be clear, if the heating circuit lower limit flow rate Vwmin and the lower flow rate set value VWOb are equal, it doesn't matter which one is the flow rate target value.

[0132] For example, as shown in Fig. 22, when the lower flow rate set value VWOb is greater than the heating circuit lower limit flow rate Vwmin, the liquid medium in the liquid circuit 3 is circulated so that the heater core liquid flow rate Vw converges to the lower flow rate set value VWOb as the flow rate target value. On the other hand, as shown in Fig. 23, when the heating circuit lower limit flow rate Vwmin is greater than the lower flow rate set value VWOb, the liquid medium in the liquid circuit 3 is circulated so that the heater core liquid flow rate Vw converges to the heating circuit lower limit flow rate Vwmin as the flow rate target value. The operating point Ph shown in Figs. 22 and 23 indicates the heater core liquid flow rate Vw and air heater output Pa achieved in this step S205.

[0133] Also, in step S205, the control unit 5 operates the air heater 28 so as to converge the air heater outlet temperature to the target blowing temperature TAO in accordance with the heating circuit lower limit flow rate Vwmin, the upper flow rate set value VWO, and the lower flow rate set value VWOb.

[0134] Specifically, assuming that the heater core liquid flow rate Vw is the above-mentioned flow rate target value, the control unit 5 determines the air heater output Pa based on the heater core liquid flow rate Vw in accordance with the correspondence shown in Figures 22 and 23, and operates the air heater 28 at the determined air heater output Pa. In this way, the control unit 5 causes the air heater outlet temperature to converge to the target blown-out temperature TAO.

[0135] Specifically, as shown in Fig. 22, when the heating circuit lower limit flow rate Vwmin is equal to or less than the lower flow rate set value VWOb, the control unit 5 operates the air heater 28 at the air heater maximum output Pam. Also, as shown in Fig. 23, when the upper flow rate set value VWO is equal to the heating circuit lower limit flow rate Vwmin, the control unit 5 turns off the air heater 28.

[0136] Furthermore, when the heating circuit lower limit flow rate Vwmin is less than the upper flow rate set value VWO and greater than the lower flow rate set value VWOb, the control unit 5 operates the air heater 28 as follows. That is, in this case, the control unit 5 operates the air heater 28 at an intermediate air heater output Pa that is less than the air heater maximum output Pam and greater than zero, so as to cause the air heater outlet temperature to converge to the target blown-out temperature TAO. In this case, the control unit 5 reduces the air heater output Pa toward zero as the heating circuit lower limit flow rate Vwmin deviates from the lower flow rate set value VWOb side toward the upper flow rate set value VWO side.

[0137] Note that when the heating circuit lower limit flow rate Vwmin is less than the upper flow rate set value VWO and greater than the lower flow rate set value VWOb, the air heater output Pa may be adjusted by feedback control. Alternatively, in this case, the air heater output Pa may be determined based on the heating circuit lower limit flow rate Vwmin, the upper flow rate set value VWO, and the lower flow rate set value VWOb in accordance with an empirical formula or map that has been experimentally determined in advance. Step S205 in FIG. 18 is followed by step S206.

[0138] In step S206, control unit 5 determines the output of liquid heater 40, using inlet liquid temperature target value TWOa as the target temperature value of the liquid medium when heating the liquid medium with liquid heater 40, and operates liquid heater 40 at the determined output. As described above, inlet liquid temperature target value TWOa is determined based on target outlet temperature TAO in step S202, and therefore liquid heater 40 is operated at an output according to that target outlet temperature TAO.

[0139] For example, when the temperature of the liquid medium flowing into the liquid heater 40 (i.e., the liquid temperature) is less than the inlet liquid temperature target value TWOa, the control unit 5 causes the liquid heater 40 to heat the liquid medium so that the heater core inlet liquid temperature TW becomes the inlet liquid temperature target value TWOa. On the other hand, when the temperature of the liquid medium flowing into the liquid heater 40 is equal to or higher than the inlet liquid temperature target value TWOa, the control unit 5 turns off the liquid heater 40. After step S206 in FIG. 18, the process returns to step S101.

[0140] In this embodiment, during the control process of FIG. 18, the air mix door 30 is operated in accordance with FIG. 11, as in the first embodiment. However, in FIG. 11, the upper inlet liquid temperature set value TWO in the first embodiment is replaced with the inlet liquid temperature target value TWOa in this embodiment. That is, in this embodiment, as shown in FIG. 11, when the heater core inlet liquid temperature TW is equal to or lower than the inlet liquid temperature target value TWOa, the door position of the air mix door 30 is set to the MAXHOT position. When the heater core inlet liquid temperature TW exceeds the inlet liquid temperature target value TWOa, the door position of the air mix door 30 is controlled so that the opening degree of the bypass passage 244 increases as the heater core inlet liquid temperature TW increases.

[0141] As described above, in this embodiment, the control unit 5 determines, as the upper flow rate set value VWO, an estimated value of the heater core liquid flow rate Vw required to set the air heater outlet temperature to the target blowing temperature TAO when the air heater 28 is turned off. The control unit 5 also determines, as the lower flow rate set value VWOb, an estimated value of the heater core liquid flow rate Vw required to set the air heater outlet temperature to the target blowing temperature TAO when the air heater 28 is in the predetermined heating operating state. Then, as shown in FIGS. 22 and 23 , the control unit 5 sets the larger of the heating circuit lower flow rate limit Vwmin and the lower flow rate set value VWOb as the flow rate target value, and controls the second pump 32 to circulate the liquid medium so that the heater core liquid flow rate Vw converges to the flow rate target value. At the same time, the control unit 5 operates the air heater 28 in accordance with the heating circuit lower limit flow rate Vwmin, the upper flow rate set value VWO, and the lower flow rate set value VWOb so as to converge the air heater outlet temperature to the target blown-out temperature TAO.

[0142] This prevents the air heater 28 from heating the blown air so that the air heater outlet temperature exceeds the target blown air temperature TAO, thereby preventing the air heater 28 from excessively heating the blown air.

[0143] (1) Furthermore, according to this embodiment, as shown in Fig. 22, when the heating circuit lower limit flow rate Vwmin is equal to or less than the lower flow rate set value VWOb, the control unit 5 operates the air heater 28 at the air heater maximum output Pam. When the heating circuit lower limit flow rate Vwmin is less than the upper flow rate set value VWO and greater than the lower flow rate set value VWOb, the control unit 5 operates the air heater 28 at an intermediate air heater output Pa that is less than the air heater maximum output Pam and greater than zero. Therefore, the air heater output Pa can be easily determined based on the magnitude relationship between the heating circuit lower limit flow rate Vwmin, the upper flow rate set value VWO, and the lower flow rate set value VWOb so as to reduce wasteful power consumption of the air heater 28.

[0144] (2) Furthermore, according to this embodiment, the control unit 5 operates the liquid heater 40 with an output corresponding to the target blow-out temperature TAO. Therefore, the output of the liquid heater 40 can be easily determined so that the output of the liquid heater 40 is not insufficient for the target blow-out temperature TAO.

[0145] Except for the points described above, this embodiment is the same as the first embodiment. In this embodiment, the same effects as those of the first embodiment can be obtained from the configuration common to the first embodiment.

[0146] (Third embodiment) Next, a third embodiment will be described, focusing on the differences from the first embodiment.

[0147] In this embodiment, unlike the first embodiment, the air heater 28 has a plurality of PTC heaters 283, as shown in Figure 24. The control unit 5 increases or decreases the air heater output Pa by increasing or decreasing the number x of PTC heaters 283 to be operated, in other words, the number x of heaters to be energized, out of all the PTC heaters 283 that the air heater 28 has. The PTC heater 283 is a heating device that maintains a constant temperature by increasing its electrical resistance as the temperature rises, and is, for example, a positive temperature coefficient thermistor. Therefore, in this embodiment, the maximum air heater output Pam is not a constant.

[0148] Note that PTC heater is an abbreviation for Positive Temperature Coefficient Heater. In addition, in the description of this embodiment, the quantity of PTC heaters 283 is sometimes expressed in units of "pieces," but this is for convenience, and the PTC heaters 283 may have shapes or configurations that are not suitable for expression in units of "pieces." Furthermore, one PTC heater 283 refers to the smallest unit that can be turned on and off by the control unit 5. Furthermore, all of the PTC heaters 283 in the air heater 28 are made the same so that, for example, the output characteristics of the PTC heaters 283 are consistent with each other.

[0149] In this embodiment, the control unit 5 does not execute the control process shown in the flowchart of Fig. 5, but instead executes the control process shown in the flowchart of Fig. 25. In this respect, too, this embodiment differs from the first embodiment. Note that steps S101 and S102 in Fig. 25 are the same as steps S101 and S102 in Fig. 5, respectively, and therefore their description will be omitted.

[0150] 25, after step S102, the process proceeds to step S303. Then, in step S303, the control unit 5 determines the maximum number n of PTC heaters 283 that can be activated to generate heat, that is, the maximum number n of heat generation.

[0151] For example, a power limit may be imposed on the power consumption of the air heater 28 due to a factor external to the air heater 28, but if there is no power limit, the control unit 5 sets the maximum heat-generating number n of the PTC heaters 283 to the total number of PTC heaters 283 that the air heater 28 has. On the other hand, if there is a power limit, the control unit 5 sets the maximum heat-generating number n of the PTC heaters 283 to the maximum number that can be used within that power limit. In other words, the maximum heat-generating number n of the PTC heaters 283 determined in step S303 is the maximum number of PTC heaters 283 that are allowed to be energized. After step S303 in FIG. 25, the process proceeds to step S304.

[0152] In step S304, the control unit 5 determines the air heater inlet target temperature THOx based on the hot air flow rate Va at MAXHOT and the target blown-out temperature TAO determined in step S101. This air heater inlet target temperature THOx is determined for each x number of operating PTC heaters 283, with the maximum heat generation number n as an upper limit.

[0153] In detail, for each number x of operating PTC heaters 283, the control unit 5 estimates the air heater inlet temperature required to make the air heater outlet temperature equal to the target blown-out temperature TAO when the operating number x of PTC heaters 283 heats the blown air. Then, for each number x of operating PTC heaters 283, the control unit 5 determines the estimated value of the air heater inlet temperature as the air heater inlet target temperature THOx. In this way, since the air heater inlet target temperature THOx is determined for each number x of operating PTC heaters, for example, if the maximum number n of heaters is 5, five air heater inlet target temperatures THOx are determined corresponding to the operating numbers x of 1 to 5.

[0154] When the number of operating units x is specified and the air heater inlet target temperature THOx is displayed, the subscript "x" of THOx is replaced with the specific number of operating units x. That is, the subscript "x" of THOx is replaced with 1, 2, 3, . . . , n-1, or n. For example, when the number of operating units x is 1, the air heater inlet target temperature THOx is displayed as air heater inlet target temperature THO1, and when the number of operating units x is n-1, the air heater inlet target temperature THOx is displayed as air heater inlet target temperature THO n-1 is displayed.

[0155] Furthermore, when the number of operating units x is set to the maximum number of heat generation n and the x number of PTC heaters 283 are heating the blown air, this corresponds to the case where the air heater 28 is in the above-mentioned predetermined heating operating state. This is because, as described above, the predetermined heating operating state is the operating state where the air heater 28 heats the blown air at the air heater maximum output Pam.

[0156] For example, in this embodiment, the air heater inlet target temperature THOx, which is an estimated value of the air heater inlet temperature, is determined for each number x of operating PTC heaters based on the hot air volume Va and the target blow-out temperature TAO at MAXHOT from the air heater inlet temperature estimation map Mthox in Fig. 26. That is, the input parameters of the air heater inlet temperature estimation map Mthox are the hot air volume Va and the target blow-out temperature TAO at MAXHOT. The air heater inlet temperature estimation map Mthox in Fig. 26 and the second inlet liquid temperature estimation map Mtwox in Fig. 27 described below are each experimentally set in advance for each number x of operating PTC heaters 283, where x ranges from 1 to all heaters.

[0157] Each air heater inlet temperature estimation map Mthox for each operating number x represents the relationship between the air heater inlet temperature and each input parameter, which has been experimentally obtained in advance, when the air heater outlet temperature becomes the target blowout temperature TAO when the air heaters 28 of that number x are energized. For example, the air heater inlet temperature estimation map Mthox when the operating number x is n-1 represents the relationship between the air heater inlet temperature and each input parameter when n-1 air heaters 28 are energized. If the air heater inlet temperature estimation map Mthox is for the case where the operating number x is n-1, then the air heater inlet target temperature THOx on the vertical axis represents the air heater inlet target temperature THOx. n-1 becomes.

[0158] The air heater inlet temperature estimation map Mthox is experimentally obtained in advance assuming MAXHOT and is stored in the control unit 5. In the air heater inlet temperature estimation map Mthox, the higher the target blown-out temperature TAO and the larger the hot air flow rate Va at MAXHOT, the higher the air heater inlet target temperature THOx, which is the estimated value of the air heater inlet temperature. After step S304 in Figure 25, the process proceeds to step S305.

[0159] In step S305, the control unit 5 first obtains the heater core liquid flow rate Vw, as in the first embodiment. After obtaining the heater core liquid flow rate Vw, the control unit 5 determines an inlet liquid temperature determination value TWOx based on the heater core liquid flow rate Vw, the heater core inlet air temperature TAhcin, the hot air flow rate Va at MAXHOT, and the air heater inlet target temperature THOx. This inlet liquid temperature determination value TWOx is determined for each number x of operating PTC heaters 283, with the maximum heat generation number n as an upper limit.

[0160] Specifically, for each x number of operating PTC heaters 283, the control unit 5 estimates the heater core inlet liquid temperature TW required to make the air heater outlet temperature equal to the target blowing temperature TAO when the x number of operating PTC heaters 283 heat the blown air. Then, for each x number of operating PTC heaters 283, the control unit 5 determines the estimated value of the heater core inlet liquid temperature TW as the inlet liquid temperature determination value TWOx. In this way, since the inlet liquid temperature determination value TWOx is determined for each x number of operating PTC heaters, for example, if the maximum number n of heaters is five, five mutually different inlet liquid temperature determination values ​​TWOx are determined.

[0161] For example, in this embodiment, the inlet liquid temperature determination value TWOx is determined for each operating number x based on the heater core liquid flow rate Vw, the heater core inlet air temperature TAhcin, the hot air flow rate Va at MAXHOT, and the air heater inlet target temperature THOx from the second inlet liquid temperature estimation map Mtwox in Fig. 27. That is, the input parameters of the second inlet liquid temperature estimation map Mtwob are the heater core liquid flow rate Vw, the heater core inlet air temperature TAhcin, the hot air flow rate Va at MAXHOT, and the air heater inlet target temperature THOx.

[0162] Each second inlet liquid temperature estimation map Mtwox for each operating number x represents the relationship between the heater core inlet liquid temperature TW and each input parameter, which has been experimentally obtained in advance, when the air heater outlet temperature becomes the target blowout temperature TAO when the air heater 28 of that number x is energized. For example, the second inlet liquid temperature estimation map Mtwox when the operating number x is n-1 represents the relationship between the heater core inlet liquid temperature TW and each input parameter when n-1 air heaters 28 are energized. If the second inlet liquid temperature estimation map Mtwox is for the operating number x of n-1, for example, the air heater inlet target temperature THOx on the horizontal axis represents the air heater inlet target temperature THOx. n-1 The inlet liquid temperature judgment value TWOx on the vertical axis is the inlet liquid temperature judgment value TWO n-1 becomes.

[0163] The second inlet liquid temperature estimation map Mtwox is experimentally obtained in advance assuming MAXHOT and is stored in the control unit 5. In the second inlet liquid temperature estimation map Mtwox, the smaller the heater core liquid flow rate Vw, the lower the heater core inlet air temperature TAhcin, and the larger the hot air flow rate Va at MAXHOT, the higher the inlet liquid temperature judgment value TWOx, which is an estimate of the heater core inlet liquid temperature TW. Furthermore, the higher the air heater inlet target temperature THOx, the higher the inlet liquid temperature judgment value TWOx. After step S305 in FIG. 25, the process proceeds to step S306.

[0164] In step S306, the control unit 5 obtains the heater core inlet liquid temperature TW detected by the heater core inlet liquid temperature sensor 453. Then, the control unit 5 calculates the heater core inlet liquid temperature TW, the inlet liquid temperature upper set value TWO, and the inlet liquid temperature judgment value TWO corresponding to the maximum number n of heat generation of the PTC heater 283. n In response to this, the air heater 28 is operated so that the air heater outlet temperature converges to the target outlet temperature TAO.

[0165] As shown in FIG. 28, the rate of change dx of the number x of the PTC heaters 283 in operation relative to the heater core inlet liquid temperature TW is calculated based on the upper set value TWO of the inlet liquid temperature and the inlet liquid temperature judgment value TWO corresponding to the maximum number n of heat generation of the PTC heaters 283. nTherefore, the number x of the PTC heaters 283 to be operated, determined in step S306, is determined based on the inlet liquid temperature determination value TWO corresponding to the maximum number n of the PTC heaters 283 to be heated. n The inlet liquid temperature judgment value TWO corresponding to the maximum number of heat generation n of the PTC heater 283 is n corresponds to the inlet liquid temperature lower setpoint of the present disclosure.

[0166] Specifically, in accordance with the correspondence relationship shown in Fig. 28, the control unit 5 determines the number x of PTC heaters 283 to be operated based on the heater core inlet liquid temperature TW, and operates the air heater 28 by energizing the determined number x of PTC heaters 283. In this way, the control unit 5 operates the air heater 28 so that the air heater outlet temperature converges to the target blow-out temperature TAO.

[0167] 28, the control unit 5 turns off the air heater 28 when the heater core inlet liquid temperature TW is equal to or higher than the inlet liquid temperature upper set value TWO. In other words, in this case, the control unit 5 sets the number x of the PTC heaters 283 to zero. On the other hand, when the heater core inlet liquid temperature TW is equal to or higher than the inlet liquid temperature upper set value TWO, the control unit 5 turns off the air heater 28. n-1 If it is less than the maximum number n, the number x of the operating PTC heaters 283 is set to the maximum number n of heat generation.

[0168] The heater core inlet fluid temperature TW is the inlet fluid temperature judgment value TWO n-1 If the inlet liquid temperature is equal to or higher than the upper set value TWO of the inlet liquid temperature, the control unit 5 determines the number of activated heaters x based on the heater core inlet liquid temperature TW in accordance with the relationship that the higher the heater core inlet liquid temperature TW, the smaller the number of activated heaters x. m ≦TW <TWO m-1 If the heater core inlet liquid temperature TW is within the range of "TWO", the control unit 5 sets the number of activated PTC heaters 283, x, to m. n-1 ≦TW <TWO n-2If it is within the range of 」, the control unit 5 sets the number of operating PTC heaters 283 to n - 1. Also, if the liquid temperature TW at the inlet of the heater core is within the range of 「TWO1 ≦ TW < TWO」, the control unit 5 sets the number of operating PTC heaters 283 to 1. After step S306 in FIG. 25, the process proceeds to step S307.

[0169] In step S307, the control unit 5 sets the temperature target value of the liquid medium when heating the liquid medium with the liquid heater 40 to the inlet liquid temperature determination value TWO n corresponding to the maximum number of heat generations n of the PTC heater 283, determines the output of the liquid heater 40, and operates the liquid heater 40 with the determined output.

[0170] In this step S307, with respect to step S106 in FIG. 5, the temperature target value of the liquid medium is changed from the inlet liquid temperature lower side setting value TWOb to the inlet liquid temperature determination value TWO n except for this, the control of the liquid heater 40 in step S307 is the same as the control of the liquid heater 40 in step S106 in FIG. 5. For example, in step S307, when the temperature of the liquid medium flowing into the liquid heater 40 is less than the inlet liquid temperature determination value TWO n the control unit 5 heats the liquid medium with the liquid heater 40 so that the liquid temperature TW at the inlet of the heater core becomes the inlet liquid temperature determination value TWO n When the temperature of the liquid medium flowing into the liquid heater 40 is equal to or higher than the inlet liquid temperature determination value TWO n the control unit 5 turns off the liquid heater 40. After step S307 in FIG. 25, the process returns to step S101.

[0171] In this embodiment as well, similar to the first embodiment, during the heating operation of the air conditioner 1, the control unit 5 controls the door position of the air mix door 30 according to the correspondence shown in FIG. 11 based on the upper inlet liquid temperature setting value TWO and the liquid temperature TW at the inlet of the heater core. For example, the control unit 5 periodically updates the door position of the air mix door 30 at the same timing as the execution timing of step S306 or S307 in FIG. 25.

[0172] (1) As described above, according to this embodiment, as shown in Figures 24 and 28, the air heater 28 has a plurality of PTC heaters 283. Therefore, adjustment of the air heater output Pa does not require any external control other than turning on and off each PTC heater 283, so adjustment of the air heater output Pa can be easily performed.

[0173] (2) Furthermore, according to this embodiment, when the number of operating PTC heaters 283 x is the maximum number of heaters n and the operating number x of PTC heaters 283 heats the blown air, this corresponds to the case where the air heater 28 is in the above-described predetermined heating operation state. This maximizes the effect of reducing wasteful power consumption by the air heater 28. Furthermore, it is possible to maximize the ability of the air heater 28 to heat the blown air, and to converge the air heater outlet temperature to the target blown air temperature TAO while minimizing the need to increase the heater core inlet liquid temperature TW. That is, in the linked mode of the liquid circuit 3, more waste heat from the fuel cell 6 can be used to heat the vehicle interior.

[0174] Except for the points described above, this embodiment is the same as the first embodiment. In this embodiment, the same effects as those of the first embodiment can be obtained from the configuration common to the first embodiment.

[0175] Although this embodiment is a modification based on the first embodiment, it is also possible to combine this embodiment with the above-described second embodiment. That is, in the second embodiment, the air heater 28 may have a plurality of PTC heaters 283.

[0176] (Other embodiments) (1) In the first and third embodiments described above, the target outlet temperature TAO is the only input parameter to the first inlet liquid temperature estimation map Mtwo in Fig. 6. However, this is merely an example. For example, in addition to the target outlet temperature TAO, the hot air flow rate Va at MAXHOT, the heater core liquid flow rate Vw, the heater core inlet air temperature TAhcin, and the like may also be input parameters to the first inlet liquid temperature estimation map Mtwo.

[0177] (2) In the second embodiment described above, the target outlet temperature TAO is the only input parameter in the first liquid flow rate estimation map Mvwo in Fig. 20, but this is just one example. For example, in addition to the target outlet temperature TAO, the hot air flow rate Va at MAXHOT and the heater core inlet air temperature TAhcin may also be input parameters to the first liquid flow rate estimation map Mvwo.

[0178] (3) In the above-described embodiments, the predetermined heating operating condition taken into account in step S103 of Fig. 5 is, for example, an operating condition in which the air heater 28 heats the blown air at the maximum air heater output Pam, but this is just one example. For example, the predetermined heating operating condition may be an operating condition in which the air heater 28 heats the blown air at an air heater output Pa that is greater than zero and slightly lower than the maximum air heater output Pam.

[0179] (4) In the third embodiment described above, when the number of operating PTC heaters 283 x is set to the maximum number of heaters n and the PTC heaters 283 of that number x heat the blown air, this corresponds to the case where the air heater 28 is in the predetermined heating operating state. However, this is merely an example. For example, when the number of operating PTC heaters 283 x is set to a predetermined number and the PTC heaters 283 of that number x heat the blown air, this may also correspond to the case where the air heater 28 is in the predetermined heating operating state. In such a case, the predetermined number may be, for example, the same as the maximum number of heaters n, or may be a number greater than 0 and slightly less than the maximum number of heaters n. The inlet liquid temperature determination value TWOx obtained when the number of operating PTC heaters 283 x is set to the predetermined number corresponds to the lower inlet liquid temperature set value of the present disclosure.

[0180] (5) In the control process of FIG. 18 in the second embodiment described above, the heating circuit lower limit flow rate Vwmin is treated as a constant, but it may also be a variable value.

[0181] (6) In each of the above-described embodiments, the flow path switching valve 34 is switched alternatively between the linked switching state shown in FIG. 3 and the independent switching state shown in FIG. 4, but this is merely an example. For example, the flow path switching valve 34 may be switched to the semi-linked switching state shown in FIG. 29 in addition to the linked switching state and the independent switching state. That is, the flow path switching valve 34 may be configured to be switched alternatively between the linked switching state, the independent switching state, and the semi-linked switching state. In the semi-linked switching state, as shown in FIG. 29, the flow path switching valve 34 interconnects the first port 34a, the second port 34b, and the third port 34c.

[0182] 2 and 29, when the flow path switching valve 34 is switched to the semi-cooperation switching state, the liquid circuit 3 enters the semi-cooperation mode. In the semi-cooperation mode, the liquid medium basically circulates in the same manner as in the cooperation mode described above, but in addition, a portion of the liquid medium that flows out from the liquid medium outlet 27b of the heater core 27 is sucked into the intake port 31b of the first pump 31 without passing through the radiators 41, 42 and the fuel cell 6.

[0183] (7) In the third embodiment described above, in step S306 of Fig. 25, the control unit 5 determines the number x of the PTC heaters 283 to be activated based on the heater core inlet fluid temperature TW in accordance with the correspondence shown in Fig. 28. However, this is just an example. For example, the control unit 5 may determine the number x of the PTC heaters 283 to be activated in accordance with the correspondence shown in Fig. 30 instead of Fig. 28.

[0184] In the example of FIG. 30, the inlet liquid temperature judgment value TWO n-1 , TWO n-2 , TWO2, TWO1, and the upper set value of the inlet liquid temperature TW. n-1 In the hysteresis based on the inlet liquid temperature TW, the liquid temperature threshold value used when determining whether to increase the number of operating units x as the heater core inlet liquid temperature TW decreases is the inlet liquid temperature determination value TWO. n-1The liquid temperature threshold value used when determining whether to reduce the number of activated units x as the heater core inlet liquid temperature TW increases is the inlet liquid temperature determination value TWO. n-1 This makes it possible to prevent frequent changes in the number x of operating PTC heaters 283.

[0185] (8) In each of the above-described embodiments, the object to be cooled by the liquid medium in the liquid circuit 3 shown in Fig. 2 is the fuel cell 6, but this is only an example. The object to be cooled may be, for example, a storage battery, an electric motor, or another object other than the fuel cell 6.

[0186] (9) In the first embodiment described above, in step S106 of FIG. 5 , for example, the liquid heater inlet liquid temperature, which is the temperature of the liquid medium flowing into liquid heater 40, is detected by a sensor or the like. Then, if the detected liquid heater inlet liquid temperature is less than the inlet liquid temperature lower set value TWOb, controller 5 causes liquid heater 40 to heat the liquid medium so that the heater core inlet liquid temperature TW becomes the inlet liquid temperature lower set value TWOb. Furthermore, if the liquid heater inlet liquid temperature is equal to or greater than the inlet liquid temperature lower set value TWOb, controller 5 turns off liquid heater 40. However, this is just one example, and for example, in step S106, controller 5 may control the operation of liquid heater 40 based not on the liquid heater inlet liquid temperature, but on the heater core inlet liquid temperature TW detected by heater core inlet liquid temperature sensor 453.

[0187] In this case, in step S106, if the detected heater core inlet liquid temperature TW is less than the inlet liquid temperature lower set value TWOb, the control unit 5 causes the liquid heater 40 to heat the liquid medium so that the heater core inlet liquid temperature TW becomes the inlet liquid temperature lower set value TWOb. Then, if the heater core inlet liquid temperature TW is equal to or greater than the inlet liquid temperature lower set value TWOb, the control unit 5 turns off the liquid heater 40. In this way, a sensor for detecting the liquid heater inlet liquid temperature is not required in controlling the liquid heater 40 in step S106. This has the advantage of eliminating the need to provide a sensor capable of detecting the liquid heater inlet liquid temperature separately from the battery outlet liquid temperature sensor 452 when the liquid circuit 3 is in independent mode.

[0188] As described above, the operation of the liquid heater 40 may be controlled based on the heater core inlet liquid temperature TW instead of the liquid heater inlet liquid temperature, which also applies to step S206 in Figure 18 in the second embodiment and step S307 in Figure 25 in the third embodiment.

[0189] (10) In the third embodiment described above, all of the PTC heaters 283 in the air heater 28 are the same so that the output characteristics of the PTC heaters 283 are the same, but this is just one example. For example, all or some of the PTC heaters 283 in the air heater 28 may have different output characteristics.

[0190] (11) The present disclosure is not limited to the above-described embodiments and can be implemented in various modifications. Furthermore, the above-described embodiments are not unrelated to each other and can be combined as appropriate, except in cases where the combination is clearly impossible.

[0191] Furthermore, in each of the above embodiments, it goes without saying that the elements constituting the embodiments are not necessarily essential unless they are particularly explicitly stated as essential or are clearly considered essential in principle. Furthermore, in each of the above embodiments, when the numbers, values, amounts, ranges, etc. of the components of the embodiments are mentioned, they are not limited to the specific numbers unless they are particularly explicitly stated as essential or are clearly limited to a specific number in principle. Furthermore, in each of the above embodiments, when the materials, shapes, positional relationships, etc. of the components are mentioned, they are not limited to the materials, shapes, positional relationships, etc. unless they are particularly explicitly stated or are clearly limited to a specific material, shape, positional relationship, etc. in principle.

[0192] In addition, in each of the above-described embodiments, although it is described that external environmental information of the vehicle (e.g., humidity outside the vehicle) is acquired from a sensor, it is also possible to eliminate the sensor and receive the external environmental information from a server or cloud external to the vehicle. Alternatively, it is also possible to eliminate the sensor and acquire related information related to the external environmental information from a server or cloud external to the vehicle, and estimate the external environmental information from the acquired related information.

[0193] The control unit 5 and the method described herein may be implemented by a special-purpose computer configured with a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the control unit 5 and the method described herein may be implemented by a special-purpose computer configured with a processor configured with one or more dedicated hardware logic circuits. Alternatively, the control unit 5 and the method described herein may be implemented by one or more special-purpose computers configured with a processor and memory programmed to perform one or more functions in combination with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory tangible storage medium.

[0194] (Aspects of the present disclosure) The present disclosure described above can be understood from the following viewpoints, for example. [First viewpoint] An air conditioning device for a vehicle, a heater core (27) provided in a liquid circuit (3) through which a liquid medium for cooling an object to be cooled (6) circulates, the heater core (27) using the liquid medium flowing out of the object to be cooled as a heat source to heat the blown air to be blown into the vehicle interior; an air heater (28) for further heating the blown air heated by the heater core; a control unit (5), The control unit determining an estimated value of the inlet liquid temperature (TW) of the heater core required to make the temperature of the blown air flowing out from the air heater equal to the target outlet temperature (TAO) when the air heater is turned off as an inlet liquid temperature upper set value (TWO); The estimated value of the inlet liquid temperature of the heater core required to make the temperature of the blown air flowing out from the air heater the target blown air temperature in a predetermined heating operation state in which the air heater heats the blown air is set as an inlet liquid temperature lower set value (TWOb, TWO n ) and an air conditioning device that operates the air heater so that the temperature of the blown air flowing out from the air heater converges to the target blowing temperature in accordance with the inlet liquid temperature, the inlet liquid temperature upper set value, and the inlet liquid temperature lower set value. [Second viewpoint] An air conditioning device for a vehicle, a heater core (27) provided in a liquid circuit (3) through which a liquid medium for cooling an object to be cooled (6) circulates, the heater core (27) using the liquid medium flowing out of the object to be cooled as a heat source to heat the blown air to be blown into the vehicle interior; an air heater (28) for further heating the blown air heated by the heater core; a flow rate adjusting device (32) capable of increasing or decreasing a heater core liquid flow rate (Vw), which is the flow rate of the liquid medium flowing through the heater core; a control unit (5), The control unit determining an estimated value of the heater core liquid flow rate required to make the temperature of the blown air flowing out from the air heater equal to a target outlet temperature (TAO) when the air heater is turned off as an upper setpoint flow rate (VWO); determining, as a lower set flow rate value (VWOb), an estimated value of the heater core liquid flow rate required to make the temperature of the blown air flowing out from the air heater the target blown air temperature under a predetermined heating operation condition in which the air heater heats the blown air; a lower limit value (Vwmin) of the heater core liquid flow rate and the lower set flow rate value, whichever is larger, as a flow rate target value, and the liquid medium is circulated by controlling the flow rate adjustment device so that the heater core liquid flow rate converges to the flow rate target value; An air conditioning device that operates the air heater so that the temperature of the blown air flowing out from the air heater converges to the target blowing temperature in accordance with the lower limit value, the upper flow rate setting value, and the lower flow rate setting value of the heater core liquid flow rate. [Third Perspective] The air conditioner according to the first or second aspect, wherein the predetermined heating operation state is an operation state in which the air heater heats the blown air at a maximum output (Pam) within an allowed range. [Fourth viewpoint] The air heater has a plurality of PTC heaters (283), The air conditioner according to a first aspect, wherein the predetermined heating operation state is an operation state in which a predetermined number of PTC heaters among the plurality of PTC heaters heat the blown air. [Fifth viewpoint] The air heater has a plurality of PTC heaters (283), The air conditioner according to a first aspect, wherein the predetermined heating operation state is an operation state in which the maximum number of PTC heaters that are allowed to be energized among the plurality of PTC heaters heat the blown air. [Sixth viewpoint] The air conditioning device according to any one of the first, fourth and fifth aspects, wherein the control unit turns off the air heater when the inlet liquid temperature is equal to or higher than the inlet liquid temperature upper set value, and when the inlet liquid temperature is lower than the inlet liquid temperature upper set value, increases the output (Pa) of the air heater as the inlet liquid temperature decreases. [Seventh viewpoint] The predetermined heating operation state is an operation state in which the air heater heats the blown air at a maximum output (Pam) within an allowable range, The air conditioning device described in a second aspect, wherein the control unit operates the air heater at the maximum output when the lower limit value of the heater core liquid flow rate is equal to or less than the lower flow rate set value, and operates the air heater at an output (Pa) less than the maximum output when the lower limit value of the heater core liquid flow rate is less than the upper flow rate set value and greater than the lower flow rate set value. [Eighth viewpoint] The air conditioner according to any one of the first to seventh aspects, further comprising a liquid heater (40) provided in the liquid circuit, the liquid heater (40) heating the liquid medium flowing out of the object to be cooled and flowing into the heater core. [Ninth viewpoint] a liquid heater (40) provided in the liquid circuit for heating the liquid medium flowing out of the object to be cooled and flowing into the heater core; The air conditioning device according to any one of the first, fourth, fifth, and sixth aspects, wherein, when the temperature of the liquid medium flowing into the liquid heater is lower than the inlet liquid temperature lower set value, the control unit causes the liquid heater to heat the liquid medium so that the inlet liquid temperature becomes the inlet liquid temperature lower set value. [10th viewpoint] a liquid heater (40) provided in the liquid circuit for heating the liquid medium flowing out of the object to be cooled and flowing into the heater core; The air conditioner according to the second or seventh aspect, wherein the control unit operates the liquid heater with an output corresponding to the target blow-out temperature. [11th viewpoint] a liquid heater (40) provided in the liquid circuit for heating the liquid medium; the liquid circuit has a flow path switching valve (34) that switches the liquid circuit between a linked mode and an independent mode; In the linked mode, a circuit configuration is established in which the liquid medium flows through the object to be cooled, the liquid heater, the heater core, and then returns to the object to be cooled, The air conditioning device according to any one of the first to seventh aspects, wherein in the independent mode, a circuit configuration (3a) in which the liquid medium circulates while flowing through the object to be cooled, and a circuit configuration (3b) in which the liquid medium flows through the liquid heater and the heater core in this order and returns to the liquid heater are respectively established. [12th viewpoint] a radiator (41, 42) provided in the liquid circuit for radiating heat from the liquid medium; the object to be cooled, the heater core, and the radiator are connected in a circular fashion so that the liquid medium flows through the object to be cooled, the heater core, and the radiator in this order in the liquid circuit, and then returns to the object to be cooled; The air conditioning device according to any one of the first to tenth aspects, wherein the liquid circuit has a bypass liquid flow passage (38) through which the liquid medium flowing out of the object to be cooled bypasses the heater core and flows to the radiator. [13th viewpoint] an air conditioning case (21) that houses the heater core and the air heater and that has formed therein a hot air passage (243) in which the heater core and the air heater are arranged and a bypass passage (244) through which the blown air flows, bypassing the heater core and the air heater; The air conditioning device according to any one of the first to twelfth aspects, further comprising: an air mix door (30) provided in the air conditioning case and configured to adjust the ratio of the air volume of the blown air flowing through the warm air passage to the air volume of the blown air flowing through the bypass passage. [14th viewpoint] an air conditioning case (21) that houses the heater core and the air heater and that has formed therein a hot air passage (243) in which the heater core and the air heater are arranged and a bypass passage (244) through which the blown air flows, bypassing the heater core and the air heater; an air mix door (30) provided in the air conditioning case for adjusting the ratio of a hot air volume (Va) that is the volume of the blown air flowing through the hot air passage to a bypass volume that is the volume of the blown air flowing through the bypass passage, The control unit When the inlet liquid temperature is equal to or lower than the inlet liquid temperature upper set value, the air mix door is controlled so that the ratio of the hot air flow rate to the total air flow rate of the hot air flow rate and the bypass air flow rate becomes maximum. An air conditioning device according to any one of the first, fourth, fifth, sixth and ninth aspects, wherein when the inlet liquid temperature exceeds the inlet liquid temperature upper set value, the air mix door is controlled so that the ratio of the warm air volume to the total air volume decreases as the inlet liquid temperature increases. [15th viewpoint] The air conditioner according to any one of the first to fourteenth aspects, wherein the object to be cooled includes a fuel cell. [Explanation of symbols]

[0195] 1 Air conditioner 3 liquid circuit 5. Control section 6 Fuel cells (to be cooled) 27 Heater core 28 Air heater TAO target outlet temperature TW Heater core inlet fluid temperature (heater core inlet fluid temperature) TWO Upper inlet temperature setting TWOb Lower inlet temperature setting

Claims

1. An air conditioning device for a vehicle, a heater core (27) provided in a liquid circuit (3) through which a liquid medium for cooling an object to be cooled (6) circulates, the heater core (27) using the liquid medium flowing out of the object to be cooled as a heat source to heat the blown air to be blown into the vehicle cabin; an air heater (28) for further heating the blown air heated by the heater core; a control unit (5), The control unit determining an estimated value of the inlet liquid temperature (TW) of the heater core required to make the temperature of the blown air flowing out from the air heater equal to the target outlet temperature (TAO) when the air heater is turned off as an inlet liquid temperature upper set value (TWO); The estimated value of the inlet liquid temperature of the heater core required to make the temperature of the blown air flowing out from the air heater the target blown air temperature in a predetermined heating operation state in which the air heater heats the blown air is set to an inlet liquid temperature lower set value (TWOb, TWO n ) and an air conditioning device that operates the air heater so that the temperature of the blown air flowing out from the air heater converges to the target blowing temperature in accordance with the inlet liquid temperature, the inlet liquid temperature upper set value, and the inlet liquid temperature lower set value.

2. An air conditioning device for a vehicle, a heater core (27) provided in a liquid circuit (3) through which a liquid medium for cooling an object to be cooled (6) circulates, the heater core (27) using the liquid medium flowing out of the object to be cooled as a heat source to heat the blown air to be blown into the vehicle cabin; an air heater (28) for further heating the blown air heated by the heater core; a flow rate adjusting device (32) capable of increasing or decreasing a heater core liquid flow rate (Vw), which is the flow rate of the liquid medium flowing through the heater core; a control unit (5), The control unit determining an estimated value of the heater core fluid flow rate required to make the temperature of the blown air flowing out from the air heater equal to a target outlet temperature (TAO) when the air heater is turned off as an upper setpoint flow rate (VWO); determining, as a lower set flow rate value (VWOb), an estimated value of the heater core liquid flow rate required to make the temperature of the blown air flowing out from the air heater the target blown air temperature under a predetermined heating operation condition in which the air heater heats the blown air; The larger of the lower limit value (Vwmin) of the heater core liquid flow rate and the lower set flow rate value is set as a flow rate target value, and the liquid medium is circulated by controlling the flow rate adjustment device so that the heater core liquid flow rate converges to the flow rate target value, An air conditioning device that operates the air heater so that the temperature of the blown air flowing out from the air heater converges to the target blowing temperature in accordance with the lower limit value, the upper flow rate setting value, and the lower flow rate setting value of the heater core liquid flow rate.

3. 3. The air conditioner according to claim 1, wherein the predetermined heating operation state is an operation state in which the air heater heats the blown air at a maximum output (Pam) within an allowable range.

4. The air heater has a plurality of PTC heaters (283), 2. The air conditioner according to claim 1, wherein the predetermined heating operation state is an operation state in which a predetermined number of the plurality of PTC heaters heat the blown air.

5. The air heater has a plurality of PTC heaters (283), 2. The air conditioner according to claim 1, wherein the predetermined heating operation state is an operation state in which the blown air is heated by a maximum number of PTC heaters that are allowed to be energized among the plurality of PTC heaters.

6. 6. The air conditioning device according to claim 1, wherein the control unit turns off the air heater when the inlet liquid temperature is equal to or higher than the inlet liquid temperature upper set value, and when the inlet liquid temperature is lower than the inlet liquid temperature upper set value, increases the output (Pa) of the air heater as the inlet liquid temperature decreases.

7. the predetermined heating operation state is an operation state in which the air heater heats the blown air at a maximum output (Pam) within an allowable range, The air conditioning device of claim 2, wherein the control unit operates the air heater at the maximum output when the lower limit value of the heater core liquid flow rate is equal to or less than the lower flow rate set value, and operates the air heater at an output (Pa) smaller than the maximum output when the lower limit value of the heater core liquid flow rate is less than the upper flow rate set value and greater than the lower flow rate set value.

8. 8. The air conditioning system according to claim 1, further comprising a liquid heater (40) provided in the liquid circuit for heating the liquid medium flowing out of the object to be cooled and flowing into the heater core.

9. a liquid heater (40) provided in the liquid circuit for heating the liquid medium flowing out of the object to be cooled and flowing into the heater core; 6. The air conditioning device according to claim 1, wherein, when the temperature of the liquid medium flowing into the liquid heater is lower than the inlet liquid temperature lower set value, the control unit causes the liquid heater to heat the liquid medium so that the inlet liquid temperature becomes the inlet liquid temperature lower set value.

10. a liquid heater (40) provided in the liquid circuit for heating the liquid medium flowing out of the object to be cooled and flowing into the heater core; The air conditioner according to claim 2 or 7, wherein the control unit operates the liquid heater with an output corresponding to the target blown air temperature.

11. a liquid heater (40) provided in the liquid circuit for heating the liquid medium; The liquid circuit has a flow path switching valve (34) that switches the liquid circuit between a linked mode and an independent mode, In the linked mode, a circuit configuration is established in which the liquid medium flows through the object to be cooled, the liquid heater, the heater core, and then returns to the object to be cooled, 8. The air conditioning device according to claim 1, wherein in the independent mode, a circuit configuration (3a) in which the liquid medium circulates while flowing through the object to be cooled, and a circuit configuration (3b) in which the liquid medium flows through the liquid heater and the heater core in that order and returns to the liquid heater are respectively established.

12. a radiator (41, 42) provided in the liquid circuit for radiating heat from the liquid medium; the object to be cooled, the heater core, and the radiator are connected in a circular fashion so that the liquid medium flows through the object to be cooled, the heater core, and the radiator in this order in the liquid circuit, and then returns to the object to be cooled; 8. The air conditioning system according to claim 1, wherein the liquid circuit has a bypass liquid flow passage (38) through which the liquid medium flowing out of the object to be cooled bypasses the heater core and flows to the radiator.

13. an air conditioning case (21) that houses the heater core and the air heater and has a hot air passage (243) in which the heater core and the air heater are arranged and a bypass passage (244) through which the blown air flows, bypassing the heater core and the air heater; 8. The air conditioning device according to claim 1, further comprising an air mix door (30) provided in the air conditioning case and configured to adjust the ratio of the air volume of the blown air flowing through the warm air passage to the air volume of the blown air flowing through the bypass passage.

14. an air conditioning case (21) that houses the heater core and the air heater and has a hot air passage (243) in which the heater core and the air heater are arranged and a bypass passage (244) through which the blown air flows, bypassing the heater core and the air heater; an air mix door (30) provided in the air conditioning case for adjusting the ratio of the hot air volume (Va) which is the volume of the blown air flowing through the hot air passage to the bypass volume which is the volume of the blown air flowing through the bypass passage, The control unit When the inlet liquid temperature is equal to or lower than the inlet liquid temperature upper set value, the air mix door is controlled so that the ratio of the hot air flow rate to the total air flow rate of the hot air flow rate and the bypass air flow rate becomes maximum.

6. An air conditioning device according to claim 1, wherein when the inlet liquid temperature exceeds the upper inlet liquid temperature set value, the air mix door is controlled so that the ratio of the warm air volume to the total air volume decreases as the inlet liquid temperature increases.

15. 8. The air conditioner according to claim 1, wherein the object to be cooled includes a fuel cell.

Images