JP6957951B2 - Air conditioning controller - Google Patents

Description

The present disclosure relates to an air conditioning control device that controls a vehicle air conditioning device.

Conventionally, an air conditioner having a vapor compression refrigeration cycle is known. In this type of air conditioner, oil that lubricates the compressor is generally used, and the oil flows out to the refrigerant circuit after lubricating the compressor, and returns to the compressor through the refrigerant circuit.

However, since oil may stay in the refrigerant circuit without returning to the compressor, some air conditioners of this type perform oil return control to return the oil to the compressor by flowing the refrigerant through the refrigerant circuit. It has been proposed (for example, the air conditioner described in Patent Document 1).

Japanese Unexamined Patent Publication No. 2008-107064

Some air conditioners for vehicles also perform oil return control as described above.

By the way, oil may stay in the evaporator, and in order to return the oil staying in the evaporator to the compressor, it is necessary to perform oil return control in which the refrigerant flows so as to pass through the evaporator.

However, when the oil return control for flowing the refrigerant through the evaporator is performed, the evaporator is cooled. As a result, when the temperature of the evaporator falls below the dew point temperature, the moisture contained in the ambient air condenses and is adsorbed on the evaporator. When the oil return control is completed and the refrigerant does not flow to the evaporator, the temperature of the evaporator gradually rises, whereby the water adsorbed on the evaporator evaporates and the ambient air becomes high humidity. Therefore, in a vehicle air conditioner, when air is blown by a blower with the defroster door open when such oil return control is performed, high humidity ambient air flows from the defroster outlet into the vehicle interior. It spills into the air, which causes the windows to become cloudy. The greater the amount of high-humidity air that flows out of the defroster outlet into the passenger compartment, the more severely the windows become cloudy.

In view of the above problems, it is an object of the present disclosure to provide an air conditioning control device that controls an air conditioning device for a vehicle so that the window of the vehicle is less likely to be fogged even when the oil return control is executed.

The air conditioning control device according to one aspect of the present disclosure is a vehicle air conditioning device having a refrigerating cycle including a compressor (2) and an evaporator (6) and providing air conditioning air cooled by the evaporator into the vehicle interior of the vehicle. It is an air conditioning control device that controls (1). The vehicle air conditioner includes a defroster outlet (18a) that blows air for air conditioning to the window of the vehicle, and additional outlets (18b, 18c) that are separate outlets from the defroster outlet. , The flow rate adjusting unit (18d) that adjusts the flow rate of air conditioning air passing through the defroster outlet by changing the opening degree, and the air conditioning from each of the defroster outlet and the additional outlet to the passenger compartment. A blower (16) that blows air to blow out air is provided. The air conditioning controller executes oil return control that returns the oil that lubricates the compressor to the compressor by circulating the refrigerant through the refrigerant circuits (8, 9) of the refrigeration cycle so as to pass through the evaporator. When the air-conditioning controller executes the oil return control while the air-conditioning air is being blown into the vehicle interior while opening the defroster outlet by the flow rate adjusting unit, the air-conditioning control device suppresses the fogging of the windows due to the temperature fluctuation of the evaporator. Execute suppression control. In the air conditioning control device, as anti-fog control, the flow rate adjusting unit is fully closed so that the air volume of the air conditioning air passing through the defroster outlet becomes zero. The air-conditioning controller operates the blower so that the amount of air blown by the blower is reduced when the fogging suppression control is executed while the air-conditioning air is blown into the vehicle interior from both the defroster outlet and the additional outlet. Blast reduction control, which is a control to change, is also executed.
Further, the air conditioning control device according to another aspect of the present disclosure has a refrigerating cycle including a compressor (2) and an evaporator (6), and provides air conditioning air cooled by the evaporator into the vehicle interior of the vehicle. It is an air conditioning control device that controls the vehicle air conditioning device (1). The vehicle air conditioner includes a defroster outlet (18a) that blows air conditioning air into the window of the vehicle, and a flow rate that adjusts the flow rate of air conditioning air passing through the defroster outlet by changing the opening degree. An adjusting unit (18d) and an evaporator temperature detecting unit (20) for detecting the temperature of the evaporator are provided. The air conditioning controller executes oil return control that returns the oil that lubricates the compressor to the compressor by circulating the refrigerant through the refrigerant circuits (8, 9) of the refrigeration cycle so as to pass through the evaporator. The air-conditioning control device executes fogging suppression control that suppresses fogging of the windows when the oil return control is executed while the air-conditioning air is being blown into the vehicle interior while the defroster outlet is opened by the flow rate adjusting unit. Even when the air conditioning control device executes the oil return control, the air conditioning control device does not execute the fogging suppression control when the temperature of the evaporator detected by the evaporator temperature detection unit is not equal to or lower than the predetermined temperature.

According to the present disclosure, the air conditioning control device suppresses fogging of vehicle windows by executing fogging suppression control when executing oil return control. This makes it difficult for the windows of the vehicle to become cloudy.

FIG. 1 is a schematic plan view showing a vehicle air conditioner controlled by a vehicle control device (air conditioner ECU) according to the first embodiment of the present disclosure. FIG. 2 is a block diagram showing components of the vehicle air conditioner shown in FIG. FIG. 3 is a diagram for explaining the problems in the present disclosure. FIG. 4 is a flowchart showing the control executed by the vehicle control device (air conditioning ECU) according to the first embodiment. FIG. 5 is a flowchart showing the control executed by the vehicle control device (air conditioning ECU) according to the second embodiment.

Hereinafter, the present embodiment will be described with reference to the accompanying drawings. In order to facilitate understanding of the description, the same components are designated by the same reference numerals as much as possible in each drawing, and duplicate description is omitted.

(First Embodiment)

The vehicle air conditioner 1 according to the present embodiment will be described with reference to FIGS. 1 to 4. The vehicle air conditioner 1 is an air conditioner that provides air for air conditioning in the vehicle interior.

First, the overall configuration of the vehicle air conditioner 1 will be described with reference to FIGS. 1 and 2. The arrows in FIG. 1 indicate the flow directions of the refrigerant and the oil.

As shown in FIG. 1, the vehicle air conditioner 1 includes a steam compression type refrigeration cycle having a compressor 2, a condenser 3, an expansion valve 4, an additional expansion valve 5, an evaporator 6, and an additional evaporator 7. There is. As a refrigerant flow path that realizes the refrigeration cycle, a circuit (hereinafter referred to as a first refrigerant circuit) 8 that circulates the refrigerant in the order of the compressor 2, the condenser 3, the expansion valve 4, the evaporator 6, the compressor 2, ... It is formed. Further, as a refrigerant flow path for realizing the refrigeration cycle, a circuit for circulating the refrigerant in the order of the compressor 2, the condenser 3, the additional expansion valve 5, the additional evaporator 7, the compressor 2, ... (hereinafter, the second refrigerant circuit). ) 9 is formed. A part of the first refrigerant circuit 8 and the second refrigerant circuit 9 is composed of a common flow path 10 and two flow paths from the common common flow path 10 (hereinafter, one is the first flow path 11 and the other is the other). Is branched into the second flow path 12) and merges with the flow path 10 after the branching. That is, the first flow path 11 is a part of the first refrigerant circuit 8, and the second flow path 12 is a part of the second refrigerant circuit 9. The first flow path 11 passes through the evaporator 6, and the second flow path 12 passes through the additional evaporator 7.

The oil that lubricates the compressor 2 also flows through the first refrigerant circuit 8 and the second refrigerant circuit 9 together with the refrigerant. The oil is held in the compressor 2 when lubricating the compressor 2, and flows out from the compressor 2 as the vehicle air conditioner 1 operates, and the first refrigerant circuit 8 or the second refrigerant circuit 8 or the second refrigerant circuit. Circulate 9.

The compressor 2 sucks in the low-temperature and low-pressure vapor-phase refrigerant, compresses the sucked vapor-phase refrigerant, and sends the high-temperature and high-pressure vapor-phase refrigerant to the condenser 3.

The condenser 3 condenses the vapor-phase refrigerant by exchanging heat with the surrounding air or the like and cooling the high-temperature and high-pressure vapor-phase refrigerant sent out from the compressor 2.

Each of the expansion valve 4 and the additional expansion valve 5 is an electric pressure reducing valve that decompresses and expands the high-pressure liquid-phase refrigerant sent out from the condenser 3. The expansion valve 4 is provided in the first flow path 11 and functions as an adjusting unit for adjusting the flow amount of the refrigerant flowing into the evaporator 6. The additional expansion valve 5 is provided in the second flow path 12 and functions as an adjusting unit for adjusting the flow amount of the refrigerant flowing into the additional evaporator 7.

Each of the evaporator 6 and the additional evaporator 7 evaporates the liquid phase refrigerant by exchanging heat with the surrounding air or the like and heating the low pressure liquid phase refrigerant. The evaporator 6 and the additional evaporator 7 are configured as heat exchangers separate from each other.

The evaporator 6 cools the air to be cooled by the latent heat of vaporization generated when the liquid phase refrigerant is evaporated.

The additional evaporator 7 is an evaporator that cools a cooling target such as a traveling component (for example, a battery) by the latent heat of vaporization generated when the liquid phase refrigerant is evaporated.

Further, the vehicle air conditioner 1 includes an air conditioner unit 13. The air conditioning unit 13 includes an air conditioning case 14, an inside / outside air switching door 15, a blower 16, the above evaporator 6, a heater core 17, and an air mix door 18.

The air conditioning case 14 is a housing member made of resin or the like. Vehicle interior air (hereinafter referred to as inside air) or vehicle interior outside air (hereinafter referred to as outside air) is introduced into the air passage 19 formed in the air conditioning case 14. The introduced inside air or outside air is blown out from the air conditioning unit 13 into the vehicle interior as air conditioning air after the temperature or humidity is adjusted by the evaporator 6 or the like before being sent to the vehicle interior through the air passage 19. Will be done.

The inside / outside air switching door 15 switches the air taken into the air passage 19 to the outside air or the inside air by opening / closing the outside air suction port 15a and the inside air suction port 15b. Further, the inside / outside air switching door 15 can change the ratio of the outside air introduced into the air passage 19 from the outside air suction port 15a and the inside air introduced into the air passage 19 from the inside air suction port 15b. ..

The blower 16 introduces air into the air passage 19 and sends the introduced air into the vehicle interior. The air introduced into the air passage 19 is passed through the evaporator 6 by the air blown by the blower 16, and is cooled by the evaporator 6. The cooled air is then sent into the vehicle interior from any of the defroster outlet 18a, the face outlet 18b, and the foot outlet 18c.

The heater core 17 heats the air in the air passage 19 by heat exchange with a heat exchange fluid (for example, engine cooling water circulating with the engine) flowing inside the heater core 17.

The air mix door 18 adjusts the ratio of the air volume of the air passing through the heater core 17 to the air volume of the air bypassing the heater core 17. By changing the opening degree of the air mix door 18, the ratio of the flow rate of air passing through the heater core 17 to the flow rate of air bypassing the heater core 17 is adjusted, whereby the temperature of the air conditioning air is adjusted.

Further, the air conditioning unit 13 has a defroster outlet 18a, a face outlet 18b, and a foot outlet 18c, and includes a defroster door 18d, a face door 18e, and a foot door 18f. The defroster outlet 18a is an outlet for blowing air conditioning air into the window of the vehicle. The face outlet 18b is an outlet for blowing out air conditioning air to the faces of occupants in the vehicle interior. The foot outlet 18c is an outlet for blowing out air conditioning air to the feet of occupants in the vehicle interior. The defroster door 18d adjusts the flow rate of the air conditioning air passing through the defroster outlet 18a by changing its opening degree, and eventually adjusts the flow rate of the air conditioning air blown out to the window of the vehicle. The face door 18e adjusts the flow rate of the air-conditioning air passing through the face outlet 18b by changing its opening degree, and eventually adjusts the flow rate of the air-conditioning air blown out to the face of the occupant in the vehicle interior. .. The foot door 18f adjusts the flow rate of the air-conditioning air passing through the foot outlet 18c by changing its opening degree, and eventually adjusts the flow rate of the air-conditioning air blown out to the feet of the occupants in the vehicle interior. The defroster outlet 18a, the face outlet 18b, and the foot outlet 18c are all part of the air passage 19.

Further, as shown in FIG. 2, the air conditioner unit 13 includes an evaporator temperature sensor 20, an operation unit 22, and an air conditioner ECU (Electronic Control Unit) 23 in the vehicle air conditioner 1.

The evaporator temperature sensor 20 detects the evaporator temperature, which is the temperature of the evaporator 6, and outputs a signal corresponding to the detected evaporator temperature.

The operation unit 22 is a part operated by an occupant when performing various operations of the vehicle air conditioner 1. The operation unit 22 has a blower switch 24 and an air conditioner switch 24a. Hereinafter, for convenience, the air conditioner switch is abbreviated as "A / C switch". Further, the operation unit 22 has a temperature setting switch (not shown), an inside air switch, an outside air switch, and the like.

The blower switch 24 is a switch that is operated when the blower 16 switches between execution and stop of blowing. The A / C switch 24a is a switch that is operated when switching between execution and stop of cooling of the air conditioning air by the refrigeration cycle. The temperature setting switch is operated when setting the air conditioning temperature in the vehicle interior. The inside air switch is operated when setting the air taken into the air passage 19 of the air conditioning case 14 to the inside air. The outside air switch is operated when setting the air taken into the air passage 19 of the air conditioning case 14 to the outside air. The operation unit 22 outputs a signal corresponding to each operation information of these switches including the A / C switch 24a.

The air-conditioning ECU 23 is a part that comprehensively controls the operation of the vehicle air-conditioning device 1. In this embodiment, the air conditioning ECU 23 corresponds to the air conditioning control device. The air-conditioning ECU 23 is mainly composed of a microcomputer having a CPU, a ROM, a RAM, and the like. The CPU executes arithmetic processing related to automatic operation control. Various programs and data related to the control of the vehicle air conditioner 1 are stored in the ROM. The calculation result of the CPU is temporarily stored in the RAM.

The air conditioning ECU 23 transmits signals to the compressor 2, the expansion valve 4, the additional expansion valve 5, the blower 16, the air mix door 18, the defroster door 18d, the face door 18e, the foot outlet 18c, and the like. Controls the operation of 4, 5, 16, 17, 18 and the like. Further, the air conditioning ECU 23 detects the evaporator temperature based on the signal output from the evaporator temperature sensor 20. Further, the air conditioner ECU 23 switches the execution and stop of the air blown by the blower 16 based on the information output from the blower switch 24, thereby switching the execution and stop of the air blown into the vehicle interior by the vehicle air conditioner 1. Further, the air conditioning ECU 23 switches between execution and stop of cooling of the air conditioning air by the refrigeration cycle based on the information output from the A / C switch 24a.

The air conditioning ECU 23 also controls to switch between a first operation mode, which is an operation mode in which the refrigerant is circulated in the first refrigerant circuit 8, and a second operation mode, which is an operation mode in which the refrigerant is circulated in the second refrigerant circuit 9. In the first operation mode, the refrigerant flows through the first flow path 11. In the second operation mode, the refrigerant flows through the second flow path 12.

In the first operation mode, the air conditioning ECU 23 opens the expansion valve 4 and closes the additional expansion valve 5. As a result, the refrigerant flows through the first flow path 11, passes through the evaporator 6, and circulates in the first refrigerant circuit 8. On the other hand, the air conditioning ECU 23 opens the additional expansion valve 5 and closes the expansion valve 4 in the second operation mode. As a result, the refrigerant flows through the second flow path 12, passes through the additional evaporator 7, and circulates in the second refrigerant circuit 9.

The air conditioning ECU 23 circulates the refrigerant in the first and second refrigerant circuits 8 and 9 in order to return the oil retained in the first and second refrigerant circuits 8 and 9 to the compressor 2 without returning to the compressor 2. Execute return control. The air conditioning ECU 23 adjusts the opening and closing of the expansion valve 4 and the additional expansion valve 5, whereby the refrigerant is circulated in the first refrigerant circuit 8 or in the second refrigerant circuit 9. The air conditioning ECU 23 repeatedly executes the oil return control every time a predetermined control cycle elapses.

By the way, oil may stay in the evaporator 6, and in order to return the oil staying in the evaporator 6 to the compressor 2, it is necessary to perform oil return control in which the refrigerant flows so as to pass through the evaporator 6. Therefore, when recovering the oil staying in the evaporator 6, the air conditioning ECU 23 performs oil return control for circulating the refrigerant in the first refrigerant circuit 8 so as to pass through at least the evaporator 6.

However, when the oil return control for flowing the refrigerant through the evaporator 6 is performed, the evaporator 6 is cooled and the temperature of the evaporator 6 is lowered as shown in FIG. When the temperature of the evaporator 6 is lower than the dew point temperature, the moisture contained in the ambient air condenses and is adsorbed on the evaporator 6. When the oil return control is completed and the refrigerant does not flow to the evaporator 6, the temperature of the evaporator 6 gradually rises, whereby the water adsorbed on the evaporator 6 evaporates and the ambient air becomes high humidity. Therefore, in an air conditioner such as the vehicle air conditioner 1, if the defroster door 18d is in the open state when such oil return control is performed, the high humidity ambient air is released to the defroster outlet 18a. It flows out into the passenger compartment, which causes the windows to become cloudy. The larger the amount of high-humidity air flowing out from the defroster outlet 18a into the vehicle interior, the more severely the windows become cloudy.

Therefore, the air conditioning ECU 23 of the present embodiment controls to suppress fogging of the window due to the temperature fluctuation of the evaporator 6 when the oil return control is executed when the defroster outlet 18a is opened by the defroster door 18d (hereinafter,). , Called fogging suppression control). This "when the defroster outlet 18a is opened by the defroster door 18d" is when the defroster door 18d has an opening degree that allows air conditioning air to pass through the defroster outlet 18a. This "when the defroster door 18d opens the defroster outlet 18a" is not limited to the case where the defroster door 18d is fully opened so that the flow rate of the air conditioning air passing through the defroster outlet 18a is maximized. Including the case where the defroster outlet 18a is slightly opened instead of being fully closed. The air conditioning ECU 23 executes the above-mentioned fogging suppression control when the A / C switch 24a is off, that is, when the air is not cooled by circulating the refrigerant in the refrigeration cycle.

Therefore, according to the present embodiment, the air conditioning ECU 23 suppresses fogging of the windows of the vehicle by executing the fogging suppression control when the oil return control is executed. This makes it difficult for the windows of the vehicle to become cloudy. The degree of change in the opening degree of the defroster door 18d in the fogging suppression control is not particularly limited, but from the viewpoint of suppressing fogging of the window, the air conditioner ECU 23 sets the flow rate of the air conditioning air passing through the defroster outlet 18a to zero. It is preferable that the defroster door 18d is fully closed so as to be. Further, the timing of executing the fogging suppression control may be at the same time as or before the oil return control, but it is necessary that the timing is after the oil return control and before the occurrence of fogging of the window at the latest.

As anti-fog control, the air-conditioning ECU 23 controls to change the opening degree of the defroster door 18d so that the flow rate of the air-conditioning air passing through the defroster outlet 18a is reduced.

Therefore, according to the present embodiment, the air conditioning ECU 23 can surely suppress the outflow of high-humidity air into the vehicle interior by closing the defroster door 18d. The air conditioning ECU 23 can suppress fogging of windows without changing the operation of the blower 16. That is, the air-conditioning ECU 23 can suppress the outflow of high-humidity air into the vehicle interior without stopping the air-conditioning air when the air-conditioning air is being blown out from the foot air outlet 18c or the face air outlet 18b.

Here, when the opening degree of the defroster door 18d is changed as described above, that is, when the defroster door 18d is closed, the foot outlet 18c or the face outlet 18b, which is a separate outlet from the defroster outlet 18a, The flow rate of air conditioning air blown out increases. This change in flow rate is unexpected for the occupant and can be a cause of impairing occupant comfort.

Therefore, when the air-conditioning ECU 23 executes the fogging suppression control when the air-conditioning air is blown out from both the defroster outlet 18a and the outlets separate from the defroster outlet 18a, the amount of air blown by the blower 16 decreases. Control to change the operation of the blower 16 (hereinafter referred to as blower reduction control) is executed. In other words, when the air conditioning ECU 23 executes the fogging suppression control when the air conditioning air is blown out from both the defroster outlet 18a and the face outlet 18b and / or the foot outlet 18c, the above-mentioned Executes blower reduction control.

Therefore, according to the present embodiment, the air conditioning ECU 23 executes the blower reduction control to reduce the amount of air blown by the blower 16. As a result, the change in air volume at the foot outlet 18c or the face outlet 18b due to the closing of the defroster door 18d is suppressed, and the comfort of the occupant can be easily maintained. The degree of decrease in the air volume by the blower 16 is preferably set so that the change in the air volume of the air conditioning air before and after the fogging suppression control is as small as possible.

The control executed by the air conditioning ECU 23 of the present embodiment will be described with reference to FIG. The series of processes shown in FIG. 4 is repeatedly executed every time a predetermined control cycle elapses.

The air conditioning ECU 23 determines whether or not the oil return control is executed as the process of the first step S10. The air conditioning ECU 23 temporarily ends a series of processes when a negative determination is made in the process of step S10, that is, when the oil return control is not executed.

If the air conditioning ECU 23 makes an affirmative determination in the process of step S10, that is, if the oil return control is being executed, whether or not air is being blown from the defroster outlet 18a into the vehicle interior as the process of step S11. Is determined. In other words, the air conditioner ECU 23 determines whether or not the blower 16 is blowing air while opening the defroster outlet 18a by the defroster door 18d. When the air conditioning ECU 23 makes a negative determination in the process of step S11, that is, when air is not blown from the defroster outlet 18a into the vehicle interior, high humidity air flows out from the defroster outlet 18a into the vehicle interior. It is determined that there is no such thing, and the series of processes is temporarily terminated.

When the air conditioning ECU 23 makes an affirmative determination in the process of step S11, that is, when air is being blown from the defroster outlet 18a into the vehicle interior, the temperature of the evaporator 6 is equal to or lower than the predetermined temperature as the process of step S12. It is determined whether or not it is. The air conditioning ECU 23 detects the temperature of the evaporator 6 based on the signal output from the evaporator temperature sensor 20, and the temperature of the evaporator 6 is equal to or lower than the predetermined temperature based on the information on the predetermined temperature stored in the ROM. It is determined whether or not it is. The information regarding the predetermined temperature stored in the ROM corresponds to the dew point temperature at which the moisture contained in the ambient air of the evaporator 6 condenses. In other words, the air conditioning ECU 23 determines whether or not the temperature of the evaporator 6 is equal to or lower than the dew point temperature as the process of step S12. The air-conditioning ECU 23 determines that there is no possibility of moisture condensing and adsorbing to the evaporator 6 when a negative determination is made in the process of step S12, that is, when the temperature of the evaporator 6 is not equal to or lower than a predetermined temperature. Process is terminated once.

When the air-conditioning ECU 23 makes an affirmative determination in the process of step S12, that is, when the temperature of the evaporator 6 is equal to or lower than the predetermined temperature, the air-conditioning ECU 23 performs the process of step S13 from the face outlet 18b and / or the foot outlet 18c. Determine whether or not air conditioning air is being blown out. In other words, the air conditioning ECU 23 determines whether or not the air conditioning air is blown out from the air outlet separate from the defroster air outlet 18a. The air conditioning ECU 23 determines whether or not air conditioning air is being blown from the face outlet 18b and / or the foot outlet 18c based on the opening degree of the face door 18e or the foot door 18f, the operating status of the blower 16, and the like.

When the air-conditioning ECU 23 makes an affirmative determination in the process of step S13, that is, when the air-conditioning air is blown out from the face outlet 18b and / or the foot outlet 18c, the above-mentioned fogging suppression is performed as the process of step S100. Control and the above-mentioned blower reduction control are executed.

Therefore, according to the present embodiment, the air conditioning ECU 23 suppresses fogging of the windows of the vehicle by executing the fogging suppression control when the oil return control is executed. This makes it difficult for the windows of the vehicle to become cloudy. Further, according to the present embodiment, the air conditioning ECU 23 executes the blower reduction control to reduce the amount of air blown by the blower 16. As a result, the change in air volume at the foot outlet 18c or the face outlet 18b due to the closing of the defroster door 18d is suppressed, and the comfort of the occupant can be easily maintained.

Further, the air conditioning ECU 23 of the present embodiment does not execute the fogging suppression control even when the oil return control is executed, when the temperature of the evaporator 6 detected by the evaporator temperature sensor 20 is not equal to or lower than a predetermined temperature.

Therefore, the air-conditioning ECU 23 can avoid unnecessarily executing the fogging suppression control even when moisture is not adsorbed on the evaporator 6 and window fogging does not occur.

When the air conditioning ECU 23 makes a negative determination in the process of step S13, that is, when the air conditioning air is not blown out from the face outlet 18b and / or the foot outlet 18c, the above-mentioned fogging suppression is performed as the process of step S101. Take control.

Therefore, the air conditioning ECU 23 suppresses the fogging of the windows of the vehicle by executing the fogging suppression control when the oil return control is executed. This makes it difficult for the windows of the vehicle to become cloudy. Since the air conditioning air is not blown out from the foot outlet 18c and the face outlet 18b, it is not necessary to control the decrease in air blowing as in the process of step S100. The series of processes shown in FIG. 4 has been described above.

According to the present embodiment of the configuration in which the first and second operation modes can be switched as described above, cooling can be performed by the evaporator 6 in the first operation mode, and additional evaporation is performed in the second operation mode. Cooling can be performed by the vessel 7.

In the case of such a configuration, in the second operation mode, the refrigerant and the oil are basically not introduced into the first flow path 11 which is the flow path on the side where the evaporator 6 is arranged. After being introduced into the two flow paths 12 and reaching the confluence point 25, the oil flows to the side of the compressor 2 without passing through the first flow path 11. However, a part of the oil introduced into the second flow path 12 and reaching the confluence point 25 may flow back to the side of the first flow path 11, that is, the side of the evaporator 6, which causes the evaporator. The oil tends to stay in 6. Therefore, it is particularly preferable to execute the above-mentioned fogging suppression control in the configuration in which the first and second operation modes are switched as described above. It is conceivable to provide a valve for suppressing the backflow of oil that causes the temperature fluctuation of the evaporator 6 to suppress the temperature fluctuation of the air conditioning air by controlling the oil return, but an additional valve or the like may be used. This is not preferable because it must be provided.

Therefore, it is preferable that the air conditioning ECU 23 executes the above-mentioned fogging suppression control when the second operation mode is terminated and the oil return control is executed.

Further, as described above, in the present embodiment, the expansion valve 4 is closed and switched to the second operation mode as compared with the first operation mode.

In such a configuration, the expansion valve 4 is closed in the second operation mode, and the flow amount of the refrigerant and the oil is limited. As a result, the refrigerant and oil that have reached the branch point 26 are basically not introduced into the first flow path 11 which is the flow path on the side where the evaporator 6 is arranged, but into the second flow path 12. It is introduced and flows to the side of the compressor 2 without passing through the first flow path 11. However, the oil flow may not be completely restricted depending on the structure and condition of the expansion valve 4. In this case, a part of the oil that has reached the branch point 26 may pass through the expansion valve 4 and leak to the side of the first flow path 11, that is, the side of the evaporator 6, and this causes the oil to leak to the evaporator 6. The oil is likely to stay.

From this, it is more preferable that the air conditioning ECU 23 executes the above-mentioned fogging suppression control when the second operation mode is terminated and the oil return control is executed.

(Second Embodiment)

The vehicle air conditioner 1 according to the second embodiment of the present disclosure will be described with reference to FIG. This embodiment is a modification of the content of the control executed by the air conditioning ECU 23 with respect to the first embodiment, and is the same as the first embodiment in other respects. Therefore, description thereof will be omitted here.

In the first embodiment, the air conditioning ECU 23 executes control for changing the opening degree of the defroster door 18d so that the flow rate of the air conditioning air passing through the defroster outlet 18a is reduced as the fogging suppression control. On the other hand, the air conditioning ECU 23 of the present embodiment executes a control for changing the operation of the blower 16 so that the amount of air blown by the blower 16 is reduced as the fogging suppression control. The air-conditioning ECU 23 changes the operation of the blower 16 so that the amount of air blown by the blower 16 decreases when the blower 16 blows air, that is, when the air-conditioning air is blown from the defroster outlet 18a into the vehicle interior. Let me.

Therefore, according to the present embodiment, the air conditioning ECU 23 can suppress the outflow of high-humidity air into the vehicle interior by reducing the amount of air blown by the blower 16 when executing the oil return control. The air conditioning ECU 23 can suppress fogging of the window without closing the defroster door 18d as in the first embodiment. Therefore, it is not necessary to deal with an increase in the air volume of the air conditioning air blown out from the foot outlet 18c or the face outlet 18b as in the first embodiment.

The air conditioning ECU 23 of the present embodiment executes control as shown in FIG. The content of this control is the same as the control in the first embodiment (that is, the control shown in FIG. 4) except that the processes of steps S13 and S100 are excluded in the first embodiment, and thus the description thereof will be omitted. ..

(Third Embodiment)

The vehicle air conditioner 1 according to the second embodiment of the present disclosure will be described. Since the present embodiment is the same as the second embodiment in that the content of the control executed by the air conditioning ECU 23 is changed with respect to the second embodiment, the description thereof will be omitted here.

In the second embodiment, the air-conditioning ECU 23 reduces the amount of air blown by the blower 16 when the air-conditioning ECU 23 executes the anti-fog control while blowing the air-conditioning air from the defroster outlet 18a into the vehicle interior as the anti-fog control. The control to change the operation of the blower 16 was executed. On the other hand, the air conditioning ECU 23 of the present embodiment continuously circulates the refrigerant in the refrigerant circuit after executing the oil return control as the fogging suppression control, thereby increasing the temperature of the evaporator 6 cooled by the oil return control. Suppress. For example, the air conditioning ECU 23 may automatically turn on the A / C switch 24a and execute control to circulate the refrigerant in the refrigerant circuit.

Therefore, according to the present embodiment, even if the air conditioning ECU 23 executes the oil return control and the temperature of the evaporator 6 falls below the dew point temperature as shown in FIG. 3, the temperature rise of the evaporator 6 thereafter is prevented. Can be suppressed. As a result, the air conditioning ECU 23 can suppress the evaporation of the moisture adsorbed on the evaporator 6, and can suppress the generation of high-humidity air that causes fogging of the windows of the vehicle. Therefore, even when this fogging suppression control is executed, the windows of the vehicle are less likely to be fogging.

In order to reliably suppress the evaporation of water, the air conditioning ECU 23 preferably executes the fogging suppression control at an early stage after the oil return control, but the oil return control is performed at a timing when the evaporation of water can be suppressed. The fogging suppression control may be executed after the elapse of a predetermined time after the completion of.

The air conditioning ECU 23 circulates the refrigerant in the refrigerant circuit and operates the blower 16 to adjust the opening degree of the air mix door 18 during the fogging suppression control, thereby defrosting the air conditioning air cooled by the evaporator 6 to the defroster outlet. It may be blown out from 18a to the window of the vehicle.

In this case, the low-temperature air-conditioning air blows out the windows of the vehicle, so that the fogging of the windows can be further suppressed.

The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Those skilled in the art with appropriate design changes to these specific examples are also included in the scope of the present disclosure as long as they have the features of the present disclosure. Each element included in each of the above-mentioned specific examples, its arrangement, conditions, shape, etc. is not limited to the illustrated one, and can be changed as appropriate. The combinations of the elements included in each of the above-mentioned specific examples can be appropriately changed as long as there is no technical contradiction.

1 Vehicle air conditioner 2 Compressor 6 Evaporator 18a Defroster outlet 18b Face outlet 18c Foot outlet 18d Defroster door 20 Evaporator temperature sensor 23 Air conditioner ECU

Claims (2)

An air conditioning control device that has a refrigeration cycle equipped with a compressor (2) and an evaporator (6) and controls a vehicle air conditioning device (1) that provides air conditioning air cooled by the evaporator into the vehicle interior of the vehicle. There,
The vehicle air conditioner includes
The defroster outlet (18a) that blows out the air conditioning air to the window of the vehicle and the additional outlets (18b, 18c) that are separate outlets from the defroster outlet are included, and the opening degree changes. To blow out the air conditioning air into the passenger compartment from each of the flow rate adjusting unit (18d) for adjusting the flow rate of the air conditioning air passing through the defroster air outlet, the defroster air outlet and the additional air outlet. Is equipped with a blower (16) that blows air to the air conditioner.
By circulating the refrigerant through the refrigerant circuits (8, 9) of the refrigeration cycle so as to pass through the evaporator, oil return control for returning the oil lubricating the compressor to the compressor is executed.
When the oil return executes control in which blows the conditioned air to the passenger compartment while opening the defroster outlet by the flow rate adjusting unit executes a fogging suppression control for suppressing the fogging of the window
As the fogging suppression control, the flow rate adjusting unit is fully closed so that the air volume of the air conditioning air passing through the defroster outlet becomes zero.
When the fogging suppression control is executed while the air conditioning air is being blown into the vehicle interior from both the defroster outlet and the additional outlet, the operation of the blower is such that the amount of air blown by the blower is reduced. An air-conditioning controller that also executes air-conditioning reduction control, which is a control that changes the air-conditioning. An air conditioning control device that has a refrigeration cycle equipped with a compressor (2) and an evaporator (6) and controls a vehicle air conditioning device (1) that provides air conditioning air cooled by the evaporator into the vehicle interior of the vehicle. There,
The vehicle air conditioner includes a defroster outlet (18a) that blows out the air conditioner air to the window of the vehicle, and the flow rate of the air conditioner air that passes through the defroster outlet as the opening degree changes. a flow rate adjusting unit that adjusts the (18 d), the evaporator temperature detecting unit for detecting a temperature of the evaporator (20), is provided,
By circulating the refrigerant through the refrigerant circuits (8, 9) of the refrigeration cycle so as to pass through the evaporator, oil return control for returning the oil lubricating the compressor to the compressor is executed.
When the oil return control is executed while the air conditioning air is being blown into the vehicle interior while the defroster outlet is opened by the flow rate adjusting unit, the fogging suppression control for suppressing fogging of the window is executed.
Even when performing the oil return control, the when the temperature of the evaporator temperature detect the evaporator detected by the unit is not equal to or lower than the predetermined temperature, do not run the fogging suppression control, air conditioning control device.

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