JP2013241097A - Vehicle air conditioning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform defrosting mode operation at proper timing and frequency.SOLUTION: A vehicle air conditioning device 10 includes: a compressor 21; an indoor capacitor 16 for dissipating heat by a compressed heat exchange medium output from the compressor 21; an outdoor heat exchanger 24 for exchanging heat between the heat exchange medium output from the indoor capacitor 15 and outdoor atmosphere; an evaporator 14 for exchanging heat between the heat exchange medium and indoor atmosphere; and a capacitor fan 24a for blowing air to the outdoor heat exchanger 24 and receiving wind passing through the outdoor heat exchanger 24 to generate power. When the power to be supplied to the capacitor fan 24a is stopped, a control apparatus 18 determines whether the outdoor heat exchanger 24 is frosted or not on the basis of electromotive force of the capacitor fan 24a detected by an electromotive force sensor 20a and a vehicle speed detected by a speed sensor 20b, and starts defrosting mode operation when it is frosted.

Description

  The present invention relates to a vehicle air conditioner.

  Conventionally, for example, in an air conditioner that performs a defrosting mode operation by a heat pump cycle, a temperature sensor that detects the surface temperature of the outdoor heat exchanger is provided, and the outdoor heat exchanger is based on a detected value of the surface temperature of the outdoor heat exchanger. There is known a vehicle air conditioner that determines whether or not it is in a frosting state and performs a defrosting mode operation according to the determination result (see, for example, Patent Document 1).

JP 2010-236709 A

By the way, according to the vehicle air conditioner according to the above-described prior art, when it is detected that the surface temperature of the outdoor heat exchanger is lowered to a predetermined temperature or less, it is determined that the outdoor heat exchanger is in a frosted state. Then, the defrosting mode operation is executed.
However, it is difficult to accurately determine whether or not the outdoor heat exchanger is actually in a frosted state only by the surface temperature of the outdoor heat exchanger. In order to ensure desired determination accuracy, for example, There is a possibility that a determination based on a large amount of actually measured data based on a combination of a plurality of other parameters such as an outside air temperature and a vehicle speed (vehicle speed) may be required.
In addition, the defrosting mode operation is merely executed based on temperature information such as the surface temperature of the outdoor heat exchanger, and the outdoor heat exchanger is not actually in a frosted state or the outdoor heat exchanger is attached. Even in the frost state, even when the performance of the outdoor heat exchanger is not deteriorated, there is a possibility that the defrosting mode operation is executed with an excessive frequency.

  This invention is made | formed in view of the said situation, and it aims at providing the vehicle air conditioner which can perform a defrost mode driving | running with an appropriate timing and frequency.

  In order to solve the above problems and achieve the object, the vehicle air conditioner according to the first aspect of the present invention compresses and outputs a heat exchange medium (for example, the compressor 21 in the embodiment). And an indoor condenser (for example, the indoor condenser 16 in the embodiment) that can dissipate heat by the compressed heat exchange medium output from the compressor, and the heat exchange medium and the vehicle exterior atmosphere output from the indoor condenser. An outdoor heat exchanger (for example, the outdoor heat exchanger 24 in the embodiment) that exchanges heat with the indoor heat exchanger (for example, an embodiment) that performs heat exchange between the heat exchange medium and the vehicle interior atmosphere. Evaporator 14) and a fan that can generate air by receiving the wind that has passed through the outdoor heat exchanger and that has passed through the outdoor heat exchanger (for example, the condenser fan in the embodiment) 24a), an electromotive force sensor for detecting the electromotive force of the blower (for example, the electromotive force sensor 20a in the embodiment), a vehicle speed sensor for detecting the vehicle speed (for example, the vehicle speed sensor 20b in the embodiment), Control means (for example, the control device 18 in the embodiment) for controlling the defrost mode operation for performing defrosting of the outdoor heat exchanger, and the control means has stopped power supply to the blower In the state, it is determined whether or not frost formation has occurred in the outdoor heat exchanger based on the electromotive force detected by the electromotive force sensor and the vehicle speed detected by the vehicle speed sensor. When it is determined that frost formation has occurred in the outdoor heat exchanger, execution of the defrosting mode operation is started.

  In the vehicle air conditioner according to the second aspect of the present invention, the control means includes the electromotive force detected by the electromotive force sensor and the vehicle speed detected by the vehicle speed sensor during the execution of the defrosting mode operation. The defrosting mode operation is stopped when it is determined whether or not frost is generated in the outdoor heat exchanger based on the result, and it is determined that frost is not generated in the outdoor heat exchanger as a result of the determination To do.

According to the vehicle air conditioner pertaining to the first aspect of the present invention, the outdoor heat exchanger is compared by comparing the electromotive force of the blower according to the vehicle speed ascertained in advance with the electromotive force actually generated in the blower. The degree of decrease in the passing wind speed can be detected. It is determined whether or not frost formation has occurred in the outdoor heat exchanger according to the detection result, and when it is determined that frost formation has occurred, the execution of the defrost mode operation is started to start the defrost mode operation. Can be executed at an appropriate timing and frequency.
As a result, when the outdoor heat exchanger is not actually in a frosted state, or when the outdoor heat exchanger is in a frosted state, the performance of the outdoor heat exchanger has not deteriorated. It is possible to prevent the defrosting mode operation from being executed.

  According to the vehicle air conditioner pertaining to the second aspect of the present invention, during execution of the defrosting mode operation, the electromotive force of the blower according to the vehicle speed ascertained in advance, and the electromotive force actually generated in the blower It is possible to detect whether or not the passing air speed of the outdoor heat exchanger that has decreased due to frosting has recovered. It is determined whether or not frost formation has occurred in the outdoor heat exchanger according to the detection result, and when it is determined that frost formation has not occurred, the defrost mode operation is appropriately stopped to stop the defrost mode operation. Can be stopped at any time.

It is a block diagram of the vehicle air conditioner which concerns on embodiment of this invention. (A) is a figure which shows the example of arrangement | positioning of the outdoor heat exchanger of a vehicle air conditioner, (B) is a block diagram which shows the connection of a fan motor and a power supply. (A) is a figure which shows the state of the heating mode driving | running of a vehicle air conditioner, (B) is a figure which shows the state of the air_conditioning | cooling mode driving | operation. It is a figure which shows the state of the dehumidification heating mode driving | operation of the vehicle air conditioner which concerns on embodiment of this invention. It is a figure which shows the state of the defrost mode driving | operation of the vehicle air conditioner which concerns on embodiment of this invention, (A) is the state of hot gas driving | operation, (B) is the state of the cooling operation for defrosting. . It is a flowchart which shows operation | movement of the vehicle air conditioner which concerns on embodiment of this invention. It is a graph which shows the example of the defrost determination reference value of the vehicle air conditioner which concerns on embodiment of this invention. It is a figure which shows the example of the change of ON / OFF of the fan power supply of the vehicle air conditioner which concerns on embodiment of this invention, and an electromotive force. It is a figure which shows the example of the change of ON / OFF of the fan power supply of the vehicle air conditioner which concerns on embodiment of this invention, the electromotive force of a fan motor, and ON / OFF of a defrost mode driving | operation.

  Hereinafter, a vehicle air conditioner according to an embodiment of the present invention will be described with reference to the accompanying drawings.

(Vehicle air conditioner)
A vehicle air conditioner 10 according to the present embodiment is mounted on, for example, an electric vehicle 1 that does not include an internal combustion engine as a vehicle drive source, and is an air conditioner capable of performing a dehumidifying heating mode operation by a heat pump cycle. As shown in FIG. 1, the air inlet 11 a provided on the upstream side of the ventilation duct 11 moves from the air outlet 11 b provided on the downstream side to sequentially open the inlet opening / closing door 12, the blower 13, and the evaporator 14. The damper 15 and the indoor capacitor 16 are provided.
Further, the vehicle air conditioner 10 includes a heat pump cycle 17 including an evaporator 14 and an indoor condenser 16, a control device 18, an evaporator sensor 19, an electromotive force sensor 20a, and a vehicle speed sensor 20b. .

The air introduction port 11 a of the ventilation duct 11 is provided so that inside air (vehicle compartment air) and outside air (vehicle compartment outside air) can be introduced into the vehicle air conditioner 10.
The air outlet 11b of the ventilation duct 11 is provided so that air can be blown from the inside of the vehicle air conditioner 10 into the vehicle interior.

  The inlet opening / closing door 12 is controlled to be opened / closed by, for example, control of the control device 18, and is provided so that the introduction amount of the inside air (vehicle compartment air) and the outside air (vehicle compartment outside air) into the ventilation duct 11 can be changed.

  The blower 13 is driven in accordance with, for example, a drive voltage applied under the control of the control device 18, and air (inside air and outside air) introduced from the air inlet 11 a passes through the air duct 11 from the upstream side to the downstream side of the air duct 11. The air flows toward 11b, that is, toward the evaporator 14 and the indoor condenser 16.

  The evaporator (indoor heat exchanger) 14 performs heat exchange between the low-pressure heat exchange medium flowing into the interior and the vehicle interior atmosphere. For example, the evaporator 14 in the ventilation duct 11 is absorbed by heat absorption when the heat exchange medium evaporates. Cool the air passing through.

  The damper 15 can be rotated by, for example, a motor (not shown) that is driven by the control of the control device 18. Of the air volume that has passed through the evaporator 14 by the blower of the blower 13, The air volume ratio with respect to the air volume that bypasses the indoor condenser 16 and is discharged into the vehicle interior is adjusted by the opening (for example, the opening with respect to the ventilation path toward the indoor condenser 16).

  The indoor condenser 16 can dissipate heat by a high-temperature and high-pressure heat exchange medium flowing into the interior, and heats the air introduced into the indoor condenser 16 in the ventilation duct 11, for example.

  The heat pump cycle 17 includes, for example, a compressor 21, an indoor condenser 16, a heating expansion valve 22, a cooling electromagnetic valve 23, an outdoor heat exchanger 24, a three-way valve 25, a gas-liquid separator 26, and a cooling. The expansion valve 27 and the electromagnetic valve 28 for dehumidification are provided.

  The compressor 21 is driven by a driving force of a motor (not shown) driven by the control of the control device 18, for example, sucks a gas phase heat exchange medium from the gas-liquid separator 26, compresses the heat exchange medium, A high-temperature and high-pressure heat exchange medium is discharged to the indoor capacitor 16.

  The indoor condenser 16 is connected to the outdoor heat exchanger 24 by a first flow path 31. Between the indoor condenser 16 and the outdoor heat exchanger 24 in the first flow path 31, a heating expansion valve 22 and A cooling electromagnetic valve 23 is arranged.

  The heating expansion valve 22 is a so-called throttle valve, expands the heat exchange medium discharged from the indoor condenser 16, and supplies the gas-liquid two-phase spray-like heat exchange medium to the outdoor heat exchanger 24 at a low temperature and low pressure. Discharge.

The cooling electromagnetic valve 23 is a heating expansion valve between the indoor condenser 16 and the outdoor heat exchanger 24 via a first branch pipe 32a on the indoor condenser 16 side and a second branch pipe 32b on the outdoor heat exchanger 24 side. For example, the opening / closing control is performed by the control device 18.
For example, the cooling electromagnetic valve 23 is closed when the heating mode operation or the dehumidifying heating mode operation is executed, and is opened when the cooling mode operation is executed.

Thereby, for example, when the heating mode operation or the dehumidifying heating mode operation is performed, the heat exchange medium discharged from the indoor condenser 16 passes through the heating expansion valve 22 and flows into the outdoor heat exchanger 24 in a low temperature and low pressure state. To do.
On the other hand, when the cooling mode operation is performed, the heat exchange medium discharged from the indoor condenser 16 passes through the cooling electromagnetic valve 23 and flows into the outdoor heat exchanger 24 in a high temperature state.

  The outdoor heat exchanger 24 is, for example, an outdoor condenser, and performs heat exchange between the heat exchange medium that has flowed into the interior and the vehicle exterior atmosphere. An outlet temperature sensor 24T that measures the temperature of the heat exchange medium that has flowed out from the outlet of the outdoor heat exchanger 24 is provided on the downstream side of the outdoor heat exchanger 24.

For example, the outdoor heat exchanger 24 can absorb heat from the vehicle exterior atmosphere by a low-temperature and low-pressure heat exchange medium flowing into the interior when performing the heating mode operation or the dehumidifying heating mode operation. The heat exchange medium is heated by absorbing heat.
On the other hand, when performing the cooling mode operation, heat can be radiated to the atmosphere outside the passenger compartment by the high-temperature heat exchange medium flowing into the interior. For example, the heat exchange medium is cooled by radiating the atmosphere outside the passenger compartment and blowing air from the condenser fan 24a. .

  The three-way valve 25 switches the heat exchange medium flowing out of the outdoor heat exchanger 24 to the gas-liquid separator 26 or the cooling expansion valve 27 and discharges it, so that the three-way valve 25 is connected to the outdoor heat exchanger 24 and the gas-liquid separator 26 side. The merging pipe 33 is connected to the third branch pipe 34 on the cooling expansion valve 27 side, and is switched and controlled by, for example, the control device 18.

For example, the three-way valve 25 discharges the heat exchange medium flowing out of the outdoor heat exchanger 24 to the inlet (not shown) of the merging pipe 33 on the gas-liquid separator 26 side when performing the heating mode operation or the dehumidifying heating mode operation. To do.
On the other hand, when the cooling mode operation is executed, the heat exchange medium flowing out of the outdoor heat exchanger 24 is discharged to the third branch pipe 34 on the cooling expansion valve 27 side.

  The gas-liquid separator 26 is connected between the outlet (not shown) of the merging pipe 33 and the inlet (not shown) of the compressor 21, and the gas-liquid of the heat exchange medium flowing out from the outlet of the merging pipe 33. The gas phase heat exchange medium is separated and sucked into the compressor 21.

  The cooling expansion valve 27 is a so-called throttle valve, and is connected between the third branch pipe 34 and the inlet (not shown) of the evaporator 14. For example, according to the valve opening controlled by the control device 18. Then, the heat exchange medium flowing out from the third branch pipe 34 is expanded, and a gas-liquid two-phase spray-like heat exchange medium at low temperature and low pressure is discharged to the evaporator 14.

  The evaporator 14 is connected between the cooling expansion valve 27 and the merge pipe 33, and is connected to an inlet (not shown) connected to the third branch pipe 34 and an inlet (not shown) of the merge pipe 33. And an outlet (not shown).

The dehumidifying solenoid valve 28 branches from the first flow path 31 to the third branch pipe 34 by a fourth branch pipe 35 provided between the indoor condenser 16 of the first flow path 31 and the first branch pipe 32a. It is provided in the second flow path 36 to be connected and is controlled to be opened and closed by, for example, the controller 18.
For example, the dehumidifying solenoid valve 28 is closed when a heating mode operation or a cooling mode operation is performed, and is opened when a dehumidifying heating mode operation is performed.

Thereby, for example, when the heating mode operation or the cooling mode operation is performed, the heat exchange medium discharged from the indoor condenser 16 passes through the fourth branch pipe 35 and circulates only through the first flow path 31 to the outdoor heat exchanger. Head to 24.
On the other hand, when the dehumidifying and heating mode operation is performed, the heat exchange medium discharged from the indoor condenser 16 branches into the first flow path 31 and the second flow path 36 in the fourth branch pipe 35, and one is the first flow path 31. Through the second flow path 36 and through the dehumidifying solenoid valve 28 and the third branch pipe 34 toward the cooling expansion valve 27.

  For example, the control device 18 includes a command signal input by an operator via an appropriate switch (not shown), and signals of detection results output from the evaporator sensor 19, the electromotive force sensor 20a, and the vehicle speed sensor 20b. Based on the above, the operation of the vehicle air conditioner 10 is controlled, and switching between the heating mode operation, the cooling mode operation, the dehumidifying heating mode operation, and the defrosting mode operation is controlled.

  The evaporator sensor 19 is disposed, for example, at a position downstream of the evaporator 14 in the ventilation duct 11, detects the temperature of the air that has passed through the evaporator 14, and outputs a detection result signal to the control device 18.

  For example, as shown in FIGS. 2A and 2B, the electromotive force sensor 20 a is provided between terminals of a fan motor 24 b that can drive a condenser fan 24 a of an outdoor heat exchanger 24 disposed in the front portion of the electric vehicle 1. The voltage (the fan motor voltage, that is, the applied voltage at the time of driving and the electromotive force at the time of regeneration) is detected, and a detection result signal is output to the control device 18.

The condenser fan 24a is disposed, for example, behind the outdoor heat exchanger 24 in the vehicle front-rear direction, and the fan motor 24b can be driven by power supply from a power source 2 such as a battery mounted on the electric vehicle 1, for example. .
Accordingly, when the fan motor 24b is driven in response to power supply from the power source 2, the condenser fan 24a can blow air to the outdoor heat exchanger 24 from the rear side toward the front side.

The condenser fan 24a can be driven to rotate by receiving wind that has passed through the outdoor heat exchanger 24 from the front side to the rear side due to, for example, running wind when the electric vehicle 1 is running, and the fan motor 24b. Can generate electric power by generating power (regeneration) by transmitting driving force from the condenser fan 24a side in a state where power supply from the power source 2 is cut off, for example.
Thus, during regeneration of the fan motor 24b in a state where the power supply from the power source 2 is interrupted, the condenser fan 24a can generate an electromotive force due to running wind.

  For these reasons, a switch 3 that can be disconnected is provided between the fan motor 24 b and the power supply 2, and connection and release (blocking) of the switch 3 are controlled by the control device 18.

  The vehicle speed sensor 20 b detects the speed (vehicle speed) based on the wheel speed of the electric vehicle 1, for example, and outputs a detection result signal to the control device 18.

  The vehicle air conditioner 10 according to the present embodiment has the above-described configuration. Next, the operation of the vehicle air conditioner 10 will be described.

(Heating mode operation)
First, during the heating mode operation of the vehicle air conditioner 10, for example, as shown in FIG. 3A, the damper 15 is opened so as to introduce the air that has passed through the evaporator 14 into the indoor condenser 16, and the cooling is performed. The solenoid valve 23 for dehumidification and the solenoid valve 28 for dehumidification are closed, and the three-way valve 25 connects the outdoor heat exchanger 24 to the inlet of the junction pipe 33.

Thereby, the high-temperature and high-pressure heat exchange medium discharged from the compressor 21 heats the air in the ventilation duct 11 by heat radiation in the indoor condenser 16.
Then, the heat exchange medium is expanded by the heating expansion valve 22 into a gas-liquid two-phase (liquid-phase rich) spray form, and then absorbs heat from the outside atmosphere of the vehicle in the outdoor heat exchanger 24 to be gas-liquid. It passes through the three-way valve 25 and the junction pipe 33 in a two-phase (gas phase rich) spray state and flows into the gas-liquid separator 26.
The heat exchange medium is gas-liquid separated in the gas-liquid separator 26, and the gas phase heat exchange medium is sucked into the compressor 21.

(Cooling mode operation)
Further, during the cooling mode operation of the vehicle air conditioner 10, for example, as shown in FIG. 3B, the damper 15 is closed so that the air that has passed through the evaporator 14 bypasses the indoor condenser 16. The electromagnetic valve 23 is opened and the dehumidifying electromagnetic valve 28 is closed, and the three-way valve 25 connects the outdoor heat exchanger 24 to the third branch pipe 34.

As a result, the high-temperature and high-pressure heat exchange medium discharged from the compressor 21 passes through the indoor condenser 16 and the cooling electromagnetic valve 23 and dissipates heat to the outdoor atmosphere in the outdoor heat exchanger 24, and the three-way valve 25 and the third branch pipe 34 and flows into the cooling expansion valve 27.
Then, the heat exchange medium is expanded by the cooling expansion valve 27 to form a gas-liquid two-phase (liquid-phase rich) spray, and then the air in the ventilation duct 11 is cooled by heat absorption in the evaporator 14.
The gas-liquid two-phase (gas-phase rich) heat exchange medium passes through the junction pipe 33 and flows into the gas-liquid separator 26 where it is separated into gas-liquid separators. Is sucked into the compressor 21.

(Dehumidifying heating mode operation)
Further, during the dehumidifying and heating mode operation of the vehicle air conditioner 10, for example, as shown in FIG. 4, the damper 15 is opened so as to introduce the air that has passed through the evaporator 14 into the indoor condenser 16, and the cooling electromagnetic The valve 23 is closed and the dehumidifying electromagnetic valve 28 is opened, and the three-way valve 25 connects the outdoor heat exchanger 24 to the inlet of the junction pipe 33.

As a result, the high-temperature and high-pressure heat exchange medium discharged from the compressor 21 heats the air in the ventilation duct 11 (that is, the air that has passed through the evaporator 14) by heat radiation in the indoor condenser 16.
Then, the heat exchange medium branches into the first flow path 31 and the second flow path 36 in the fourth branch pipe 35, one of which flows through the first flow path 31 toward the outdoor heat exchanger 24, and the other It flows through the second flow path 36, passes through the dehumidifying electromagnetic valve 28 and the third branch pipe 34, and travels toward the cooling expansion valve 27.

  That is, one heat exchange medium flows into the heating expansion valve 22 from the fourth branch pipe 35 and is expanded by the heating expansion valve 22 to form a gas-liquid two-phase (liquid phase rich) spray. Furthermore, the outdoor heat exchanger 24 absorbs heat from the atmosphere outside the passenger compartment, passes through the three-way valve 25 and the merging pipe 33 and flows into the gas-liquid separator 26 in the form of a gas-liquid two-phase (gas-phase rich) spray.

  The other heat exchange medium flows from the fourth branch pipe 35 into the cooling expansion valve 27 and is expanded by the cooling expansion valve 27 to form a gas-liquid two-phase (liquid phase rich) spray. Further, the air in the ventilation duct 11 is cooled to the dew point by absorbing heat in the evaporator 14, and then dehumidified and flows into the gas-liquid separator 26 through the merging pipe 33 in a gas-liquid two-phase (gas-phase rich) state. To do.

(Defrost mode operation)
During the heating mode operation of the vehicle air conditioner 10 described above, the outdoor heat exchanger 24 absorbs heat from the outside air, so that the outdoor heat exchanger 24 may be frosted. If frost formation occurs, the heat transfer coefficient of the outdoor heat exchanger 24 decreases and heat absorption becomes insufficient, so that heating of the vehicle interior becomes insufficient. Therefore, when it is determined that the outdoor heat exchanger 24 has been frosted during the heating mode operation, the defrosting mode operation is performed.
The defrosting mode operation is, for example, a defrosting cooling operation or a hot gas operation, or a switching operation in which the defrosting cooling operation and the hot gas operation are alternately switched in an appropriate order.

FIG. 5 is a diagram illustrating a state of the defrosting mode operation of the vehicle air conditioner, in which (A) is a hot gas operation state and (B) is a defrosting cooling operation state.
The hot gas operation shown in FIG. 5 (A) is similar to the heating mode operation shown in FIG. 3 (A), but differs in the following points. In the heating mode operation, the heating expansion valve 22 is opened with a small diameter, the heat exchange medium compressed by the compressor 21 is expanded and flows into the outdoor heat exchanger 24, and the outdoor heat exchanger 24 absorbs heat. On the other hand, in the hot gas operation, the heating expansion valve 22 is opened with a large diameter, and the heat exchange medium (hot gas) compressed by the compressor 21 is allowed to flow into the outdoor heat exchanger 24 as it is. Heat is dissipated at 24.

  When the compressor 21 compresses the heat exchange medium, the compressor 21 itself generates heat, and this heat is transmitted to the heat exchange medium to increase the temperature of the heat exchange medium. The heat exchange medium (hot gas) whose temperature has risen flows into the indoor condenser 16 to dissipate heat, and heats the air in the ventilation duct 11. Thereby, warm air is supplied into the vehicle interior.

The heat exchange medium flowing out of the indoor condenser 16 passes through the heating expansion valve 22 and flows into the outdoor heat exchanger 24. In the hot gas operation, since the heating expansion valve 22 is opened with a large diameter, the heat exchange medium does not expand in the heating expansion valve 22 and flows into the outdoor heat exchanger 24 as it is. Since this heat exchange medium dissipates heat without absorbing heat by the outdoor heat exchanger 24, the outdoor heat exchanger 24 can be defrosted.
The heat exchange medium flowing out from the outdoor heat exchanger 24 passes through the gas-liquid separator 26, returns to the compressor 21, and circulates.

  The defrosting cooling operation shown in FIG. 5 (B) is almost the same as the cooling mode operation shown in FIG. 3 (B). In any operation, the heat exchange medium compressed by the compressor 21 flows into the outdoor heat exchanger 24 to dissipate heat, and further flows into the evaporator 14 to absorb heat. As described above, in the cooling operation for defrosting, the heat exchange medium dissipates heat in the outdoor heat exchanger 24, so that the outdoor heat exchanger 24 can be defrosted.

  The cooling operation for defrosting and the cooling mode operation differ in the following points. In the cooling mode operation, the damper 15 is closed so that the air introduced into the ventilation duct 11 and passing through the evaporator 14 bypasses the indoor condenser 16. In contrast, in the defrosting cooling operation, the damper 15 is opened so that the air that has passed through the evaporator 14 passes through the indoor condenser 16.

  In the cooling operation for defrosting, the air in the ventilation duct 11 is cooled by the heat absorption in the evaporator 14 as in the cooling mode operation, so that the temperature of the air supplied into the vehicle compartment is lower than that in the heating mode operation. . On the other hand, the heat exchange medium compressed by the compressor 21 and flowing into the indoor condenser 16 radiates heat to the air passing through the indoor condenser 16. Therefore, in the cooling operation for defrosting of the present embodiment, the damper 15 is opened so that the air that has passed through the evaporator 14 passes through the indoor condenser 16. Thereby, since the temperature fall of the air supplied to a vehicle interior is suppressed, a passenger | crew's discomfort can be reduced.

Below, the process which switches execution and a stop of the defrost mode driving | operation by the vehicle air conditioner 10 is demonstrated.
Note that the processing from step S01 to step S09 shown below is repeatedly executed at a timing such as a predetermined cycle, for example.

First, for example, in step S01 shown in FIG. 6, it is determined whether or not the heating mode operation is being executed.
If this determination is “NO”, the flow proceeds to return.
On the other hand, if this determination is “YES”, the flow proceeds to step S 02.

  Next, in step S02, the vehicle speed of the electric vehicle 1 is detected, and based on the detection result, the predetermined data stored in advance is referred to, and the defrost determination reference value for the electromotive force V of the fan motor 24b is determined. get.

The predetermined data stored in advance is data indicating the correspondence between the vehicle speed of the electric vehicle 1 and the defrost determination reference value, for example, as shown in FIG.
The defrost determination reference value is, for example, the power generation of the fan motor 24b in the power supply stop state when the traveling wind having a strength according to the vehicle speed of the electric vehicle 1 passes through the outdoor heat exchanger 24 and rotates the condenser fan 24a. This is a determination threshold value set for the electromotive force generated by (regeneration).

For example, in the predetermined data shown in FIG. 7, the defrost determination reference value is set to change in an increasing tendency as the vehicle speed increases.
If the electromotive force V actually generated in the fan motor 24b is less than the defrost determination reference value with respect to the defrost determination reference value associated with the appropriate detection value of the vehicle speed, the outdoor heat exchanger 24 It is determined that the degree of decrease in the passing air speed of the outdoor heat exchanger 24 is greater than a predetermined tolerance due to the occurrence of frost formation.
On the other hand, when the electromotive force V actually generated in the fan motor 24b is larger than the defrost determination reference value, the outdoor heat exchanger 24 is not frosted or the outdoor heat exchanger 24 is frosted. Even if this occurs, it is determined that the degree of decrease in the passing air speed of the outdoor heat exchanger 24 is less than the predetermined tolerance.

  Next, in step S03, the switch 3 is switched from connection to release (shut off), and power supply from the power source 2 to the fan motor 24b is shut off (fan power supply OFF).

Next, in step S04, the electromotive force V of the fan motor 24b in a power supply stop state is detected.
Next, in step S05, it is determined whether or not the detected electromotive force V is less than a defrost determination reference value corresponding to the detected vehicle speed.
If this determination is “NO”, the flow proceeds to step S 08 described later.
On the other hand, if this determination is “YES”, the flow proceeds to step S 06.

And in step S06, execution of a defrost mode driving | operation is started.
In step S07, the electromotive force V of the fan motor 24b in the power supply stop state is detected, and it is determined whether or not the detected electromotive force V is larger than the defrost determination reference value corresponding to the detected vehicle speed. To do.
When this determination result is “NO”, the above-described determination process of step S07 is repeatedly executed.
On the other hand, if the determination is “YES”, the flow proceeds to step S08.

Next, in step S08, the defrosting mode operation is stopped, the switch 3 is switched from open (shut off) to connection, and power is supplied from the power source 2 to the fan motor 24b (fan power ON).
In step S09, the heating mode operation is resumed and the process proceeds to the end.

Thereby, as shown in FIG. 8, for example, when the heating mode operation is performed, the fan power ON and the fan power OFF are alternately repeated, and the electromotive force V is detected by the electromotive force sensor 20a when the fan power is OFF.
And if the detected electromotive force V becomes less than the defrost determination reference value according to the vehicle speed at this time, execution of a defrost mode driving | operation will be started.

For example, as shown in FIG. 9, when the fan power supply is switched from the fan power supply ON to the fan power supply OFF at time t1, the electromotive force V detected by the electromotive force sensor 20a is a predetermined applied voltage applied to the fan motor 24b by the power supply 2. Changes to a downward trend.
For example, even when frost formation has not occurred in the outdoor heat exchanger 24, or even if frost formation has occurred in the outdoor heat exchanger 24, the degree of decrease in the passing air speed of the outdoor heat exchanger 24 is a predetermined tolerance. If it is less than the value, the detected electromotive force V becomes equal to the electromotive force of the condenser fan 24a caused by the traveling wind having a strength corresponding to the vehicle speed at this time. In this case, the defrosting mode operation is not executed, the fan power supply is switched from the fan power supply OFF to the fan power supply ON at an appropriate timing (for example, time t3), and the heating mode operation is resumed.

On the other hand, for example, when the degree of decrease in the passing air speed of the outdoor heat exchanger 24 is greater than a predetermined tolerance due to frost formation in the outdoor heat exchanger 24, the detected electromotive force V Is smaller than the electromotive force generated by the traveling wind having a strength corresponding to the vehicle speed at this time.
For example, after time t2, when the detected electromotive force V becomes less than the defrost determination reference value corresponding to the vehicle speed at this time, execution of the defrost mode operation is started.
For example, when the detected electromotive force V becomes larger than the defrost determination reference value corresponding to the vehicle speed at time t3 during execution of the defrost mode operation, the defrost mode operation is stopped and the fan power supply Switching from OFF to fan power ON turns on the heating mode operation.

As described above, according to the vehicle air conditioner 10 according to the present embodiment, the electromotive force of the condenser fan 24a corresponding to the vehicle speed ascertained in advance is compared with the electromotive force V actually generated in the condenser fan 24a. By doing so, it is possible to detect the degree of decrease in the passing air speed of the outdoor heat exchanger 24. It is determined whether or not frost formation has occurred in the outdoor heat exchanger 24 according to the detection result, and when it is determined that frost formation has occurred, the execution of the defrost mode operation is started to start the defrost mode. Driving can be performed at an appropriate timing and frequency.
Thereby, when the outdoor heat exchanger 24 is not actually in a frosted state, or when the performance of the outdoor heat exchanger 24 is not deteriorated even when the outdoor heat exchanger 24 is in a frosted state, it is excessive. It is possible to prevent the defrosting mode operation from being executed at a frequency.

  Furthermore, during execution of the defrosting mode operation, by comparing the electromotive force of the condenser fan 24a corresponding to the vehicle speed ascertained in advance with the electromotive force V actually generated in the condenser fan 24a in the power supply stop state, It can be detected whether or not the passing air speed of the outdoor heat exchanger 24 that has decreased due to frosting has recovered. It is determined whether or not frost formation has occurred in the outdoor heat exchanger 24 according to the detection result. When it is determined that frost formation has not occurred, the defrost mode operation is stopped by stopping the defrost mode operation. You can stop at the right time.

  It should be noted that the technical scope of the present invention is not limited to the above-described embodiment, and includes various modifications made to the above-described embodiment without departing from the spirit of the present invention. That is, the configuration of the above-described embodiment is merely an example, and can be changed as appropriate.

DESCRIPTION OF SYMBOLS 1 Electric vehicle 10 Vehicle air conditioner 14 Evaporator (indoor heat exchanger)
16 Indoor condenser 18 Control device (control means)
20a Electromotive force sensor 20b Vehicle speed sensor 21 Compressor 24 Outdoor heat exchanger 24a Condenser fan 24b Fan motor

Claims (2)

A compressor that compresses and outputs the heat exchange medium;
An indoor condenser capable of dissipating heat by the heat exchange medium after compression output from the compressor;
An outdoor heat exchanger that performs heat exchange between the heat exchange medium output from the indoor condenser and the vehicle exterior atmosphere;
An indoor heat exchanger for exchanging heat between the heat exchange medium and the vehicle interior atmosphere;
An air blower capable of blowing air to the outdoor heat exchanger and generating electricity by receiving wind passing through the outdoor heat exchanger;
An electromotive force sensor for detecting an electromotive force of the blower;
A vehicle speed sensor for detecting the vehicle speed;
Control means for controlling a defrosting mode operation for defrosting the outdoor heat exchanger,
The control means causes frost formation in the outdoor heat exchanger based on the electromotive force detected by the electromotive force sensor and the vehicle speed detected by the vehicle speed sensor in a state where power supply to the blower is stopped. The vehicle air conditioner is configured to start the defrosting mode operation when it is determined that the outdoor heat exchanger is frosted as a result of the determination. Whether the control means is frosted in the outdoor heat exchanger based on the electromotive force detected by the electromotive force sensor and the vehicle speed detected by the vehicle speed sensor during execution of the defrosting mode operation. 2. The vehicle air conditioning according to claim 1, wherein the defrosting mode operation is stopped when it is determined whether or not frost formation has occurred in the outdoor heat exchanger as a result of the determination. apparatus.

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