Air conditioner for vehicle

Abstract

To provide an air conditioner for a vehicle which can reduce power consumption during heating.SOLUTION: An air conditioner for a vehicle includes an air conditioning unit having a heater core for heating air, a heating circuit which supplies a heat medium to the heater core, a heat pump circuit which heats the heat medium in the heating circuit, and an air conditioning controller which controls the heating circuit and heat pump circuit. The heating circuit includes a heater for heating the heat medium. The air conditioning controller includes: a first temperature control part which heats the heater core by the heat pump circuit and the heater so that a temperature of the heater core becomes a first temperature when a target temperature of the heater core is lower than a highest temperature as an upper limit value of the temperature of the heater core and the temperature of the heater core is below the first temperature which is lower than the target temperature when heating is started; and a second temperature control part which stops the heater or reduces an output of the heater, and heats the heater core by the heat pump circuit until the temperature of the heater core becomes the target temperature after the temperature of the heater core reaches the first temperature.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a vehicle air conditioner including a heating circuit that supplies a heat medium to a heater core, and a heat pump circuit that heats the heat medium in the heating circuit. [Background technology]

[0002] Battery-equipped electric vehicles (BEVs) run by driving a motor with battery power. Because BEVs are not equipped with engines, they cannot use the engine's exhaust heat for heating. Even electric vehicles equipped with engines, such as hybrid electric vehicles (HEVs), may have insufficient heating capacity because the engine produces little exhaust heat. For this reason, air conditioning systems for electric vehicles that cannot use the engine's exhaust heat for heating use a heat pump and a heater together to obtain heating capacity.

[0003] Patent Document 1 discloses an air conditioner including a refrigeration cycle in which a refrigerant circulates and a high water temperature cycle in which a cooling water circulates. The refrigeration cycle includes a compressor that compresses the refrigerant and a condenser that exchanges heat between the refrigerant and the cooling water. The high water temperature cycle includes a main heater that heats the cooling water, a heater core that heats the air, and a water pump that circulates the cooling water. The main heater generates heat by power supplied from the battery during heating, and heats the cooling water. The heater core is heated by the condenser and the cooling water heated by the main heater. The air heated by the heater core is used during heating. In addition, the refrigeration cycle operates during heating, and high-temperature, high-pressure refrigerant compressed by the compressor is sent to the condenser, and the condenser exchanges heat between the refrigerant and the cooling water, thereby heating the cooling water. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-93561 A Summary of the Invention [Problem to be solved by the invention]

[0005] When a heater is used for heating, a large amount of battery power is consumed, shortening the driving range of an electric vehicle. In order to extend the driving range, if only a heat pump, which is more energy efficient than a heater, is used, the heating capacity will be insufficient. In other words, even if heating is started, the interior of the vehicle will not warm up immediately, significantly reducing the comfort of the user. In particular, in low-temperature situations such as winter or cold regions, it is necessary to use a heater to compensate for the lack of heating. Therefore, there is a demand for reducing power consumption during heating while ensuring a minimum heating capacity so as not to reduce the comfort of the user.

[0006] An object of the present invention is to provide a vehicle air conditioner capable of reducing power consumption during heating. [Means for solving the problem]

[0007] An air conditioning device for a vehicle according to one aspect of the present invention comprises: an air conditioning unit having a heater core for heating air; a heating circuit for supplying a heat medium to the heater core; a heat pump circuit that heats the heat medium in the heating circuit; an air conditioning controller that controls the heating circuit and the heat pump circuit; The heating circuit has a heater that heats the heat medium, The air conditioning controller includes: a first temperature control unit that, when starting heating, raises the temperature of the heater core by the heat pump circuit and the heater so that the temperature of the heater core becomes the first temperature when the target temperature of the heater core is lower than a maximum temperature that is an upper limit value of the temperature of the heater core and the temperature of the heater core is lower than a first temperature that is lower than the target temperature; and a second temperature control unit that stops the heater or reduces the output of the heater after the temperature of the heater core reaches the first temperature, and raises the temperature of the heater core using the heat pump circuit until the temperature of the heater core reaches the target temperature. Effect of the Invention

[0008] In the above vehicle air conditioner, when heating starts, if a predetermined condition is satisfied, the first temperature control unit and the second temperature control unit control the temperature of the heater core. When raising the temperature of the heater core to a target temperature, the first temperature control unit uses the heat pump circuit and the heater in combination to raise the temperature to the first temperature. By raising the temperature of the heater core to the first temperature in a short time, it is possible to prevent the user's comfort from being impaired. After raising the temperature of the heater core to the first temperature, the second temperature control unit raises the temperature of the heater core to the target temperature. The second temperature control unit mainly uses the heat pump circuit to raise the temperature of the heater core, and stops the heater or reduces the output of the heater. Since the use of the heater is minimized, the power consumption due to the use of the heater is small. Therefore, the above vehicle air conditioner can achieve both comfort and energy saving. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a vehicle air conditioner according to an embodiment. [Diagram 2] FIG. 2 is another schematic diagram showing the configuration of the vehicle air conditioner according to the embodiment. [Diagram 3] FIG. 3 is a diagram showing an example of a temperature map used during heating in the vehicle air conditioner according to the embodiment. [Figure 4] FIG. 4 is a diagram showing an example of a change in temperature of a heater core when control is performed by an air conditioning controller of a vehicle air conditioner according to the embodiment. [Diagram 5] FIG. 5 is a flowchart showing a control procedure performed by the air conditioning controller of the vehicle air conditioner according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] A specific example of a vehicle air conditioner according to an embodiment of the present invention will be described with reference to the drawings. In each drawing, the same or corresponding parts are given the same reference numerals. The size of the members shown in each drawing is expressed for the purpose of clarifying the description, and does not necessarily represent the actual dimensions. Note that the present invention is not limited to the following examples, but is indicated by the claims, and includes all modifications within the meaning and scope equivalent to the claims.

[0011] <Vehicle air conditioning system> The vehicle air conditioner 1A of the embodiment is an air conditioner mounted on an electric vehicle 1. The electric vehicle 1 is, for example, a BEV, a HEV, or a FCEV (Fuel Cell Electric Vehicle). As shown in Figs. 1 and 2, the vehicle air conditioner 1A includes an air conditioning unit 2, a heating circuit 3, a heat pump circuit 4, and an air conditioning controller 5. The air conditioning unit 2 has a heater core 26 that heats air. The heating circuit 3 has a heater 31 that heats a heat medium supplied to the heater core 26. The heat pump circuit 4 heats the heat medium in the heating circuit 3. The air conditioning controller 5 controls the heating circuit 3 and the heat pump circuit 4. Fig. 1 shows the operation of the vehicle air conditioner 1A during heating operation. Fig. 2 shows the operation of the vehicle air conditioner 1A during cooling operation.

[0012] One of the features of the vehicle air conditioner 1A of the embodiment is that the air conditioning controller 5 has a first temperature control unit 51 and a second temperature control unit 52. By controlling the temperature of the heater core 26 by the first temperature control unit 51 and the second temperature control unit 52, it is possible to reduce power consumption during heating.

[0013] (Air conditioning unit) The air conditioning unit 2 is a device that conditions the air inside the vehicle cabin. The air conditioning unit 2 is also called HVAC (Heating, Ventilation and Air Conditioning). The air conditioning unit 2 adjusts the temperature of air taken in from the inlet 2i and sends the temperature-adjusted air into the vehicle cabin from the air outlet 2o. Although not shown, the inlet 2i has an outside air inlet that takes in air outside the vehicle cabin, an inside air inlet that takes in air inside the vehicle cabin, and a switching door that opens and closes the outside air inlet and the inside air inlet. When the switching door closes the inside air inlet, the outside air inlet is open and air is taken in from the outside air inlet. When the switching door closes the outside air inlet, the inside air inlet is open and air is taken in from the inside air inlet.

[0014] The air conditioning unit 2 has a heater core 26, an evaporator 27, an air mix door 28, and a blower 29. In the air conditioning unit 2, the evaporator 27, the air mix door 28, and the heater core 26 are arranged in this order from the inlet 2i toward the outlet 2o. The blower 29 draws in air from the inlet 2i and blows the drawn air toward the outlet 2o. The output of the blower 29 is adjusted to adjust the volume of air blown out from the outlet 2o.

[0015] The evaporator 27 is a component that cools air. During cooling operation, a heat medium is supplied to the evaporator 27 from the heat pump circuit 4 described later. Hereinafter, the heat medium flowing through the heat pump circuit 4 is referred to as a second heat medium. The second heat medium supplied to the evaporator 27 expands by the cooling expansion valve 46 and becomes low temperature and low pressure. The cooling expansion valve 46 is, for example, an electric expansion valve. By supplying the low-temperature second heat medium to the evaporator 27, the evaporator 27 becomes low temperature, and the air passing through the evaporator 27 is cooled. The evaporator 27 is provided with an evaporator temperature sensor 27t. The evaporator temperature sensor 27t may be one that detects the temperature of the air around the evaporator 27, or may be one that detects the temperature of the second heat medium supplied to the evaporator 27. When detecting the temperature of the second heat medium supplied to the evaporator 27, the evaporator temperature sensor 27t is provided in a flow path between the cooling expansion valve 46 and the evaporator 27. The cooling operation here includes a dehumidification operation. The temperature of the second heat medium that has passed through the evaporator 27 increases due to heat exchange with the air.

[0016] The heater core 26 is a component that heats air. The heater core 26 is disposed downstream of the evaporator 27. During heating operation, a heat medium from the heating circuit 3 is supplied to the heater core 26. Hereinafter, the heat medium flowing through the heating circuit 3 is referred to as a first heat medium. By supplying the high-temperature first heat medium to the heater core 26, the heater core 26 becomes hot, and the air passing through the heater core 26 is heated. The heating operation here also includes a defrost operation. The temperature of the first heat medium that has passed through the heater core 26 is reduced by heat exchange with the air.

[0017] The air mix door 28 is a component that adjusts the ratio of air passing through the heater core 26 to air bypassing the heater core 26. The air mix door 28 is disposed between the evaporator 27 and the heater core 26. When the air mix door 28 is open, the air that has passed through the evaporator 27 passes through the heater core 26. When the air mix door 28 is closed, the air that has passed through the evaporator 27 bypasses the heater core 26. During heating operation, the air mix door 28 is open, the ratio of air passing through the heater core 26 increases, and hot air is discharged from the air outlet 2o. During cooling operation, the air mix door 28 is closed, the ratio of air passing through the heater core 26 decreases, and cold air is discharged from the air outlet 2o. By adjusting the opening degree of the air mix door 28, the air cooled by the evaporator 27 and the air heated by the heater core 26 are mixed, and the temperature of the air blown out from the air outlet 2o is adjusted. The air outlet 2o is provided with an air outlet temperature sensor 25 that detects the temperature of the air blown out from the air outlet 2o.

[0018] (Heating circuit) The heating circuit 3 is a circuit that supplies a first heat medium to the heater core 26. The first heat medium circulates in the heating circuit 3. The first heat medium is a cooling water such as a long-life coolant (LLC). The heating circuit 3 in this example has a heater 31 that heats the first heat medium and a water pump 32 that circulates the first heat medium. The heater 31 is an electric heater such as a high voltage heater (HVH: High Voltage Heater). The water pump 32 is, for example, an electric water pump. The heating circuit 3 in this example has a flow path configured so that the first heat medium sent out from the water pump 32 returns to the water pump 32 via the heater 31 and the heater core 26. During heating operation, the water pump 32 is operated to circulate the first heat medium in the heating circuit 3, and the first heat medium is supplied to the heater core 26. The heater 31 heats the first heat medium, and the heater core 26 is heated. During the cooling operation, the heater 31 and the water pump 32 are stopped, and the first heat medium is not supplied to the heater core 26.

[0019] By controlling the output of the heater 31, it is possible to adjust the temperature of the first heat medium supplied to the heater core 26. For example, by increasing the power supplied to the heater 31, the first heat medium becomes hotter, and the temperature of the heater core 26 increases. When the power supplied to the heater 31 is maximized, the output of the heater 31 becomes maximum.

[0020] The heating circuit 3 of this example is provided with a first temperature sensor 35a and a second temperature sensor 35b. The first temperature sensor 35a detects the temperature of the first heat medium supplied to the heater core 26. The first temperature sensor 35a is provided in a flow path between the heater 31 and the heater core 26. The second temperature sensor 35b detects the temperature of the first heat medium that has passed through the heater core 26. The second temperature sensor 35b is provided in a flow path between the heater core 26 and the water pump 32.

[0021] The heating circuit 3 may be provided with a reserve tank 33. The reserve tank 33 is a tank for temporarily storing the first heat medium that overflows from the heating circuit 3 due to thermal expansion caused by a temperature rise of the first heat medium. The reserve tank 33 also has a function of separating air bubbles generated in the heating circuit 3. The reserve tank 33 separates the first heat medium and air bubbles in the heating circuit 3 and removes the air bubbles in the heating circuit 3, thereby making it possible to keep the pressure in the heating circuit 3 stable. In this example, the reserve tank 33 is connected in series to the heating circuit 3. The reserve tank 33 is disposed in a flow path between the heater core 26 and the water pump 32.

[0022] The heating circuit 3 of this example is capable of heating the first heat medium in the heating circuit 3 by the heat pump circuit 4, which will be described in detail later. A heat exchanger 43 of the heat pump circuit 4, which will be described later, is connected to the heating circuit 3 of this example. Therefore, even if the heater 31 is not operating during heating operation, the heater core 26 can be heated only by the heat pump circuit 4. Furthermore, the heating circuit 3 of this example is also capable of heating the first heat medium in the heating circuit 3 by the heat pump circuit 4 and the heater 31. When the heater core 26 cannot be sufficiently heated only by the heat pump circuit 4, the heater core 26 can be heated by both the heat pump circuit 4 and the heater 31.

[0023] In Fig. 1, the flow of the first heat medium in the heating circuit 3 during heating operation is indicated by arrows. In Fig. 1, the type of arrow is changed depending on the temperature of the first heat medium in the heating circuit 3. A hollow arrow indicates a high temperature, and a hatched arrow indicates a medium temperature. A high temperature here is, for example, a temperature of 50°C or higher and 70°C or lower. A medium temperature is, for example, a temperature of 30°C or higher and lower than 50°C.

[0024] (Heat pump circuit) The heat pump circuit 4 functions as a circuit for heating the first heat medium in the heating circuit 3 during heating operation. The heat pump circuit 4 functions as a circuit for supplying the second heat medium to the evaporator 27 during cooling operation. The second heat medium circulates in the heat pump circuit 4. The second heat medium has the property of becoming hot when compressed and becoming cold when expanded. The second heat medium is, for example, hydrofluorocarbon (HFC). The heat pump circuit 4 in this example has a condenser 40, a switching valve 41, a compressor 42, a heat exchanger 43, a heating expansion valve 44, and a cooling expansion valve 46.

[0025] In Fig. 1, the flow of the second heat medium in the heat pump circuit 4 during heating operation is indicated by arrows. In Fig. 2, the flow of the second heat medium in the heat pump circuit 4 during cooling operation is indicated by arrows. In Figs. 1 and 2, as with the heating circuit 3, the type of arrow is changed depending on the temperature of the second heat medium in the heat pump circuit 4. An open arrow indicates a high temperature, a hatched arrow indicates a medium temperature, and a solid black arrow indicates a low temperature. A low temperature is, for example, a temperature below 15°C, or even below 10°C.

[0026] The heat pump circuit 4 of this example has a first flow path 4a and a second flow path 4b. The first flow path 4a is a flow path of the second heat medium used during heating operation. The first flow path 4a includes a condenser 40, a compressor 42, a heat exchanger 43, and a heating expansion valve 44. As shown in FIG. 1, the first flow path 4a is configured such that the second heat medium sent from the compressor 42 is sent to the condenser 40 via the heat exchanger 43 and the heating expansion valve 44, and then returns from the condenser 40 to the compressor 42. The second flow path 4b is a flow path of the second heat medium used during cooling operation. The second flow path 4b includes the condenser 40, the compressor 42, the heat exchanger 43, and a cooling expansion valve 46. As shown in FIG. 2, the second flow path 4b is configured so that the second heat medium sent out from the compressor 42 is sent to the condenser 40 via the heat exchanger 43 and the heating expansion valve 44, and then returns from the condenser 40 to the compressor 42 via the cooling expansion valve 46 and the evaporator 27.

[0027] The switching valve 41 switches the flow path through which the second heat medium flows between the first flow path 4a and the second flow path 4b. The switching valve 41 is, for example, a solenoid valve. During heating operation, the switching valve 41 is opened and the second heat medium flows through the first flow path 4a. During cooling operation, the switching valve 41 is closed and the second heat medium flows through the second flow path 4b.

[0028] The compressor 42 compresses and discharges the low-pressure second heat medium sent from the accumulator 45. The compressor 42 is, for example, an electric compressor. The second heat medium compressed to a high temperature and high pressure by the compressor 42 is sent to the heat exchanger 43.

[0029] The heat exchanger 43 exchanges heat between the high-temperature second heat medium sent from the compressor 42 and the first heat medium in the heating circuit 3. The heat exchanger 43 has a first heat exchange section 43a through which the first heat medium of the heating circuit 3 flows, and a second heat exchange section 43b through which the second heat medium of the heat pump circuit 4 flows. The first heat exchange section 43a and the second heat exchange section 43b are thermally connected to each other, so that heat exchange is performed between the second heat medium in the second heat exchange section 43b and the first heat medium in the first heat exchange section 43a. The heat exchanger 43 is, for example, a water-cooled condenser. During heating operation, the first heat medium in the heating circuit 3 is heated by the heat exchanger 43 performing heat exchange between the high-temperature second heat medium and the first heat medium. The heater core 26 is heated by the first heat medium in the heating circuit 3 being heated. The temperature of the second heat medium that has passed through the heat exchanger 43 is reduced by heat exchange with the first heat medium. The temperature of the compressed second heat medium can be adjusted by controlling the compressor 42. For example, the second heat medium can be compressed to a higher temperature and pressure by increasing the rotation speed of the compressor 42. The higher the temperature of the second heat medium sent from the compressor 42 to the heat exchanger 43, the higher the temperature of the first heat medium in the heating circuit 3, and therefore the temperature of the heater core 26 increases.

[0030] The second heat medium discharged from the heat exchanger 43 is sent to the condenser 40 through the heating expansion valve 44. The heating expansion valve 44 is, for example, an electric expansion valve. When the heating expansion valve 44 is ON, the second heat medium passing through the heating expansion valve 44 is expanded. When the heating expansion valve 44 is OFF, the second heat medium is not expanded by the heating expansion valve 44 and passes through as it is. During heating operation, the heating expansion valve 44 is ON, the second heat medium is expanded by the heating expansion valve 44, and the low-temperature, low-pressure second heat medium is sent to the condenser 40. During cooling operation, the heating expansion valve 44 is OFF, the second heat medium passes through the heating expansion valve 44 as it is, and the high-temperature second heat medium is sent to the condenser 40.

[0031] The condenser 40 is a device that exchanges heat between the second heat medium in the heat pump circuit 4 and the outside air. The condenser 40 is disposed outside the vehicle cabin. The outside air is taken in from the front grille 12 by the fan 11. When the outside air hits the condenser 40, heat exchange occurs between the second heat medium flowing through the condenser 40 and the outside air. During heating operation, the condenser 40 exchanges heat between the low-temperature second heat medium and the outside air, so that the second heat medium receives heat from the outside air. Therefore, the second heat medium flowing through the condenser 40 is heated. The temperature of the second heat medium that has passed through the condenser 40 increases due to heat exchange with the outside air. On the other hand, during cooling operation, the condenser 40 exchanges heat between the high-temperature second heat medium and the outside air, so that the heat of the second heat medium is taken away by the outside air. Therefore, the second heat medium flowing through the condenser 40 is cooled. The temperature of the second heat medium that has passed through the condenser 40 decreases due to heat exchange with the outside air.

[0032] During heating operation, as shown in FIG. 1, the second heat medium discharged from the condenser 40 passes through the first flow path 4a and is recovered in the accumulator 45. The accumulator 45 separates the liquefied second heat medium and supplies only the vaporized refrigerant to the compressor 42. During cooling operation, as shown in FIG. 2, the second heat medium discharged from the condenser 40 is sent to the evaporator 27 through the second flow path 4b and then recovered in the accumulator 45. The second heat medium sent to the evaporator 27 expands by the cooling expansion valve 46, and the low-temperature, low-pressure second heat medium is supplied to the evaporator 27.

[0033] The heat pump circuit 4 of this example is provided with a first temperature sensor 47a, a second temperature sensor 47b, a third temperature sensor 47c, a fourth temperature sensor 47d, and a pressure sensor 48. The first temperature sensor 47a detects the temperature of the second heat medium sent from the compressor 42 to the heat exchanger 43. The second temperature sensor 47b detects the temperature of the second heat medium discharged from the heat exchanger 43. The third temperature sensor 47c detects the temperature of the second heat medium discharged from the condenser 40. The fourth temperature sensor 47d detects the temperature of the second heat medium passed through the evaporator 27. The pressure sensor 48 detects the pressure of the second heat medium discharged from the heat exchanger 43. The second temperature sensor 47b and the pressure sensor 48 are disposed in a flow path between the heat exchanger 43 and the heating expansion valve 44.

[0034] (Air conditioning controller) The air conditioning controller 5 controls the heating circuit 3 and the heat pump circuit 4 to air-condition the vehicle interior using the air conditioning unit 2. During heating operation, the air conditioning controller 5 controls the blower 29 of the air conditioning unit 2, the heater 31 and the water pump 32 of the heating circuit 3, and the switching valve 41, the compressor 42, and the heating expansion valve 44 of the heat pump circuit 4.

[0035] The air conditioning controller 5 is configured, for example, by an electronic control unit (ECU). The ECU includes a processor, a memory, a timer, etc. The memory stores a control program to be executed by the processor, and various data, etc. The processor performs various processes such as arithmetic processing and judgment processing required to execute the control program. The air conditioning controller 5 operates when the processor executes the control program stored in the memory. The above-mentioned multiple processors, which are physically separated, may cooperate with each other to execute the above-mentioned processes.

[0036] During heating operation, the air conditioning controller 5 controls the heating circuit 3 and the heat pump circuit 4 so that the temperature of the heater core 26 becomes the target temperature. When starting the heating operation, the air conditioning controller 5 in this example controls the temperature of the heater core 26 by the first temperature control unit 51 and the second temperature control unit 52 if a predetermined condition is satisfied. The predetermined condition is when the target temperature of the heater core 26 is lower than the maximum temperature and the temperature of the heater core 26 is less than a first temperature that is lower than the target temperature.

[0037] When heating starts, if a predetermined condition is satisfied, the first temperature control unit 51 controls the heat pump circuit 4 and the heater 31 to raise the temperature of the heater core 26 to a first temperature. After the temperature of the heater core 26 reaches the first temperature, the second temperature control unit 52 controls the heat pump circuit 4 to stop the heater 31 or reduce the output of the heater 31 and raise the temperature of the heater core 26 until the temperature of the heater core 26 reaches a target temperature.

[0038] The temperature of the heater core 26 is substantially equal to the temperature of the first heat medium supplied to the heater core 26. The temperature of the heater core 26 can be obtained from the temperature of the first heat medium detected by the first temperature sensor 35a. The temperature of the heater core 26 may be obtained from the temperature of the air outlet 2o detected by the air outlet temperature sensor 25. Since the air blown out from the air outlet 2o is heated by the heater core 26, there is a correlation between the temperature of the air blown out from the air outlet 2o and the temperature of the heater core 26. Therefore, the temperature of the heater core 26 can be obtained from the temperature of the air outlet 2o.

[0039] The target temperature of the heater core 26 means the final target temperature set during heating operation. The target temperature is the temperature of the heater core 26 that is set so that the air temperature inside the vehicle cabin becomes the heating set temperature. The target temperature is set, for example, based on a temperature map as shown in FIG. 3. The horizontal axis of the temperature map shown in FIG. 3 indicates the outside air temperature (°C), and the vertical axis indicates the target temperature (°C). The target temperature is set according to the outside air temperature, as shown by the solid line graph in FIG. 3. In the example of the temperature map shown in FIG. 3, for example, when the outside air temperature is -5°C, the target temperature is set to 65°C. When the outside air temperature is 5°C, the target temperature is set to 60°C.

[0040] The outside air temperature can be detected by an outside air temperature sensor (not shown) provided in the vehicle air conditioner 1A. The air temperature inside the vehicle compartment can be detected by an inside air temperature sensor (not shown) provided in the vehicle air conditioner 1A.

[0041] The first temperature means an initial target temperature set when heating starts. The first temperature is set, for example, based on a temperature map as shown in FIG. 3. As shown by the dashed line graph in FIG. 3, the first temperature is lower than the above-mentioned target temperature shown by the solid line. In other words, the first temperature is smaller than the target temperature. The first temperature is the temperature of the heater core 26 set so that the user feels that the air blown out from the air outlet 2o is warm. The first temperature is set, for example, so that the temperature of the air blown out from the air outlet 2o is 30°C or higher and 45°C or lower, preferably 35°C or higher and 40°C or lower. In the example of the temperature map shown in FIG. 3, when the outside air temperature is -5°C, the first temperature is set to 60°C. When the outside air temperature is 5°C, the first temperature is set to 55°C.

[0042] The maximum temperature is the upper limit of the temperature of the heater core 26. The maximum temperature means the upper limit of the temperature to which the heater core 26 can be raised when the heater 31 is operated at maximum output to heat the first heat medium. For example, during defrost operation or when the heating setting temperature is equal to or higher than a predetermined temperature, the heater core 26 is raised to the maximum temperature. The predetermined temperature here is, for example, 29°C.

[0043] Fig. 4 shows, by a solid line graph, the change in temperature of heater core 26 over time when temperature control is performed by first temperature control unit 51 and second temperature control unit 52. The horizontal axis of Fig. 4 indicates time (s), and the vertical axis indicates temperature Tc (°C) of heater core 26. Time t0 on the horizontal axis is the time when heating operation is started. Temperature Tt on the vertical axis is the target temperature described above, and temperature T1 is the first temperature described above.

[0044] The dashed line graph in Fig. 4 shows the change over time in temperature Tc of the heater core 26 when conventional temperature control is performed. Conventional control is a control in which the heater core 26 is heated up to a target temperature Tt in one go by using the heat pump circuit 4 and the heater 31 in combination. 01 is the time at which the temperature Tc reaches the target temperature Tt when the heater core 26 is heated to the target temperature Tt by using the heat pump circuit 4 and the heater 31 in combination.

[0045] When heating starts, if the above-mentioned predetermined conditions are satisfied, temperature control is performed by the first temperature control unit 51. The first temperature control unit 51 heats up the heater core 26 to the first temperature T1. When heating up the heater core 26 to the first temperature T1, the heat pump circuit 4 and the heater 31 are used in combination. Therefore, it is possible to heat up the heater core 26 to the first temperature T1 in a short time. By heating up the heater core 26 to the first temperature T1, it is possible to blow out hot air that the user feels is warm from the air outlet 2o, and it is possible to suppress a loss of comfort for the user. The time t1 on the horizontal axis is the time when the temperature Tc reaches the first temperature T1.

[0046] After the heater core 26 is heated to the first temperature T1, the second temperature control unit 52 performs temperature control. When heating the heater core 26 from the first temperature T1 to the target temperature Tt, the heat pump circuit 4 is mainly used, and the heater 31 is not used, or, if the heater 31 is used, the output of the heater 31 is reduced. By minimizing the use of the heater 31, the power consumption due to the use of the heater 31 is reduced. By heating the heater core 26 to the target temperature Tt, the comfort of the user can be ensured. Time t2 on the horizontal axis is the time when heating from the first temperature T1 to the target temperature Tt begins. Time t3 on the horizontal axis is the time when the temperature Tc reaches the target temperature Tt.

[0047] As shown in FIG. 4, when the heater core 26 is heated from the first temperature T1 to the target temperature Tt, the heater core 26 is gradually heated. The heating rate of the heater core 26 is, for example, 1° C. / min or more and 5° C. / min or less. When the heating rate of the heater core 26 is 1° C. / min or more, the time until the temperature Tc reaches the target temperature Tt can be shortened. When the heating rate of the heater core 26 is 5° C. / min or less, the heater core 26 can be easily heated by the heat pump circuit 4 alone. The heating rate of the heater core 26 may be 3° C. / min or less, or even 2° C. / min or less.

[0048] As shown in Fig. 4, after the temperature Tc of the heater core 26 reaches the first temperature T1, the temperature Tc may be maintained. In this example, the temperature Tc is maintained for a fixed time from time t1 to time t2. By maintaining the temperature Tc of the heater core 26 for a fixed time, the output of the heat pump circuit 4 is stabilized before the heater core 26 starts to increase in temperature. The time for which the temperature Tc is maintained is, for example, 1 minute or more and 15 minutes or less.

[0049] In the air conditioning controller 5 of this embodiment, when the heater core 26 is heated to the target temperature Tt, the first temperature control section 51 uses the heat pump circuit 4 and the heater 31 in combination to heat the heater core 26 to the first temperature T1. After that, when the second temperature control section 52 heats the heater core 26 from the first temperature T1 to the target temperature Tt, the heat pump circuit 4 is used and the use of the heater 31 is minimized. Compared to the conventional control in which the heat pump circuit 4 and the heater 31 are used in combination to heat the heater core 26 to the target temperature Tt, the period during which the heat pump circuit 4 and the heater 31 are used in combination is shortened, and the use of the heater 31 is minimized. Therefore, the power consumption during heating can be reduced.

[0050] Control Procedure 5, the control procedures by the first temperature control unit 51 and the second temperature control unit 52 when starting the heating operation will be described below. The heating operation is started by inputting a signal to turn on the heating switch to the air conditioning controller 5. When the heating operation is started, the heating circuit 3 and the heat pump circuit 4 are activated.

[0051] <Step S1> When heating starts, in step S1, the first temperature control unit 51 determines whether the target temperature Tt of the heater core 26 is less than the maximum temperature Th. The target temperature Tt is obtained from a temperature map. The temperature map is stored in the memory of the ECU constituting the air conditioning controller 5. If the condition of step S1 is not met, the process proceeds to step S01, and normal processing, which will be described later, is performed. The case where the condition of step S1 is not met is when the target temperature Tt=the maximum temperature Th, such as during the defrost operation described above.

[0052] <Step S2> If the condition of step S1 is satisfied, the process proceeds to step S2. In step S2, the first temperature control unit 51 determines whether the current temperature Tc of the heater core 26 is less than a first temperature T1. The first temperature T1 is obtained from a temperature map. The temperature Tc of the heater core 26 is obtained by the first temperature sensor 35a. If the condition of step S2 is not satisfied, the process proceeds to step S21, which will be described later.

[0053] <Step S3-Step S5> When the condition of step S2 is satisfied, the first temperature control unit 51 heats up the heater core 26 so that the temperature Tc of the heater core 26 becomes the first temperature T1. In this example, each process from step S3 to step S5 is performed. In step S3, the first temperature T1 is set as a target. In step S4, the heat pump circuit 4 and the heater 31 are operated to heat up the heater core 26. In step S5, it is determined whether the temperature Tc of the heater core 26 has reached the first temperature T1. If the determination in step S5 is No, that is, if the temperature Tc is less than the first temperature T1, step S5 is repeated, and the heater core 26 is heated by the heat pump circuit 4 and the heater 31 until the temperature Tc of the heater core 26 reaches the first temperature T1. When heating up the heater core 26 in step S4, the output of the heater 31 may be set to maximum.

[0054] <Step S6-Step S7> When the temperature Tc of the heater core 26 reaches the first temperature T1 in step S5, the temperature control by the first temperature control unit 51 is terminated and the temperature control by the second temperature control unit 52 is started. After the temperature Tc of the heater core 26 reaches the first temperature T1, the second temperature control unit 52 raises the temperature of the heater core 26 until the temperature Tc of the heater core 26 reaches the target temperature Tt. In this example, each process from step S6 to step S9 is performed. In step S6, the heater 31 is stopped. In step S7, the temperature Tc of the heater core 26 is maintained for a certain period of time. That is, the compressor 42 of the heat pump circuit 4 is controlled so that the temperature Tc of the heater core 26 is kept at the first temperature T1. The time for maintaining the temperature Tc of the heater core 26 is, for example, 10 minutes. When the temperature Tc of the heater core 26 cannot be maintained by the heat pump circuit 4 alone in maintaining the temperature Tc of the heater core 26 in step S7, the heater 31 may be operated to use the heat pump circuit 4 and the heater 31 in combination. However, when the heater 31 is used, the output of the heater 31 is reduced below the output of the heater 31 in step S4. Specifically, the output of the heater 31 is reduced below the output of the heater 31 when the heater core 26 is heated to the first temperature T1 by the heat pump circuit 4 and the heater 31.

[0055] <Step S8-Step S9> In step S7, the temperature Tc of the heater core 26 is maintained for a certain period of time, and then in step S8, the target temperature Tt is set as the target. In step S9, it is determined whether the temperature Tc of the heater core 26 has reached the target temperature Tt. If the determination in step S9 is No, that is, if the temperature Tc is less than the target temperature Tt, step S9 is repeated, and the heater core 26 is heated until the temperature Tc of the heater core 26 reaches the target temperature Tt. When proceeding from step S7 to step S8 and step S9, the heater core 26 is heated by the heat pump circuit 4. When the heater core 26 is heated in step S9, if the heater core 26 cannot be heated by the heat pump circuit 4 alone, the heater 31 may be operated to use the heat pump circuit 4 and the heater 31 in combination. However, when the heater 31 is used, the output of the heater 31 is reduced below that of the heater 31 in step S4. When the heater core 26 is heated in step S9, it may be heated slowly to the target temperature Tt. The temperature rise rate of the heater core 26 is, for example, 1° C. / min.

[0056] When the temperature Tc of the heater core 26 reaches the target temperature Tt in step S9, the temperature control by the second temperature control unit 52 is terminated. After the temperature Tc of the heater core 26 reaches the target temperature Tt, the air conditioning controller 5 controls the compressor 42 of the heat pump circuit 4 so that the temperature Tc of the heater core 26 is maintained at the target temperature Tt. When the temperature Tc of the heater core 26 is to be maintained at the target temperature Tt in step S9 by the heat pump circuit 4 alone, the heater 31 may be operated to use both the heat pump circuit 4 and the heater 31. However, when the heater 31 is used, the output of the heater 31 is reduced from that of the heater 31 in step S4.

[0057] <Step S01> When the condition of step S1 is not satisfied, that is, when the target temperature Tt=the maximum temperature Th, the heat pump circuit 4 and the heater 31 are used together to heat the heater core 26 to the target temperature Tt. As a specific process, after the heat pump circuit 4 and the heater 31 are operated in step S01, the process proceeds to the above step S8 → step S9. The output of the heater 31 is set to the maximum, for example. In this case, the heater core 26 is heated by the heat pump circuit 4 and the heater 31 until the temperature Tc of the heater core 26 reaches the target temperature Tt in step S9. During the above-mentioned defrost operation, the heat pump circuit 4 and the heater 31 are used together, so that the heater core 26 can be heated to the target temperature Tt in a short time. After the temperature Tc of the heater core 26 reaches the target temperature Tt, the heater 31 is stopped, and the compressor 42 of the heat pump circuit 4 is controlled so that the temperature Tc of the heater core 26 is maintained at the target temperature Tt. If the temperature of the heater core 26 cannot be maintained by the heat pump circuit 4 alone, the heater 31 may be operated to use both the heat pump circuit 4 and the heater 31. However, when the heater 31 is used, the output of the heater 31 is reduced from that in step S9. Specifically, the output of the heater 31 is reduced from that when the heater core 26 is heated to the target temperature Tt by the heat pump circuit 4 and the heater 31 after the start of the heating operation. In other words, from time t0 to time t 01 The output of the heater 31 is reduced below the output during the period in which the heat pump circuit 4 and the heater 31 are used together.

[0058] <Step S21-Step S22> If the condition of step S2 is not satisfied, i.e., if the temperature Tc of the heater core 26 is equal to or higher than the first temperature T1, then in step S21, the current temperature Tc of the heater core 26 is set as the target. That is, the first temperature T1 is set as the temperature Tc. In step S22, the heat pump circuit 4 is operated, and then the process proceeds to step S7. Since the temperature of the heater core 26 is already equal to or higher than the first temperature T1, it is not necessary to use the heat pump circuit 4 and the heater 31 in combination to raise the temperature of the heater core 26 to the first temperature T1. A situation in which the temperature of the heater core 26 is already equal to or higher than the first temperature T1 at the start of heating occurs, for example, when the heating operation is stopped once and then immediately started. [Explanation of symbols]

[0059] 1 Electric vehicles 1A Vehicle air conditioning system 11 Fan, 12 Front Grill 2 Air Conditioning Unit 2i inlet, 2o outlet, 25 outlet temperature sensor 26 heater core, 27 evaporator, 27t evaporator temperature sensor 28 Air mix door, 29 Blower 3 Heating circuit 31 heater, 32 water pump, 33 reserve tank 35a first temperature sensor, 35b second temperature sensor 4 Heat pump circuit 4a first flow path, 4b second flow path 40 condenser, 41 switching valve, 42 compressor 43 Heat exchanger, 43a first heat exchange section, 43b second heat exchange section 44 Heating expansion valve, 45 Accumulator, 46 Cooling expansion valve 47a first temperature sensor, 47b second temperature sensor 47c third temperature sensor, 47d fourth temperature sensor 48 Pressure Sensor 5 Air conditioning controller, 51 First temperature control section, 52 Second temperature control section Tc Hitacore temperature, Tt target temperature, T1 first temperature, Th maximum temperature

Claims

[Claim 1] an air conditioning unit having a heater core for heating air; a heating circuit for supplying a heat medium to the heater core; a heat pump circuit that heats the heat medium in the heating circuit; an air conditioning controller that controls the heating circuit and the heat pump circuit; The heating circuit has a heater that heats the heat medium, The air conditioning controller includes: a first temperature control unit that, when starting heating, raises the temperature of the heater core by the heat pump circuit and the heater so that the temperature of the heater core becomes the first temperature when the target temperature of the heater core is lower than a maximum temperature that is an upper limit value of the temperature of the heater core and the temperature of the heater core is lower than a first temperature that is lower than the target temperature; and a second temperature control unit that stops the heater or reduces an output of the heater and raises the temperature of the heater core by the heat pump circuit after the temperature of the heater core reaches the first temperature until the temperature of the heater core reaches the target temperature. Vehicle air conditioning system.

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