JP7375058B2 - air conditioner - Google Patents

Description

The present invention relates to an air conditioner for air conditioning a driver's cab of a vehicle.

Patent Document 1 discloses a technique for preventing overdischarge of a vehicle battery. Specifically, when the remaining capacity of the battery decreases to a predetermined value, the control unit limits the output of the electric compressor of the air conditioner to reduce the power consumption of the electric compressor. Further, when the remaining capacity of the battery decreases to a specified value lower than the predetermined specified value, the control section stops the electric compressor.

Japanese Patent Application Publication No. 2005-045883

By the way, there are various methods for calculating the remaining battery power, such as a simple voltage measurement method. The voltage measurement method takes advantage of the characteristics of a battery, since as the remaining capacity of the battery decreases, the voltage of the battery also decreases. However, the remaining battery power and voltage are not necessarily in a proportional relationship, so the battery voltage does not accurately represent the remaining power. Then, when the power consumption of the electric compressor and the air conditioning intensity of the air conditioner are low, the remaining battery capacity when the battery voltage drops to a predetermined value will be the same as when the electric compressor's power consumption and the air conditioning intensity of the air conditioner are high. There is a possibility that the remaining capacity of the battery is different from the one when the voltage of the battery drops to the predetermined value. Therefore, even if the air conditioner and electric compressor stop when the battery voltage drops to a predetermined value, depending on the output of the electric compressor and the strength of the air conditioner, the battery may not be able to start the engine when the air conditioner is stopped. There is a possibility that it is in a discharge state.

Therefore, the present invention has been made in view of the above circumstances, and is intended to prevent over-discharge of the battery when the refrigeration cycle device of an air conditioner is stopped, regardless of the air conditioning intensity of the refrigeration cycle device of the air conditioner. purpose.

In order to solve the above problems, an air conditioner includes a refrigeration cycle device that air-conditions the driver's cabin of a vehicle by being operated by battery power, and a control unit that controls the air conditioning intensity of the refrigeration cycle device in stages. , wherein the control unit includes: determining means for determining a threshold value according to the air conditioning intensity of the refrigeration cycle apparatus; comparing means for comparing the threshold value determined by the determining means with the voltage of the battery; and the comparing means. stopping means for stopping the refrigeration cycle device when the voltage of the battery is equal to or lower than the threshold value as a result of comparison by the means; If the air conditioning strength of the refrigeration cycle device is classified into a weak group with lower strength than that, and the air conditioning strength of the refrigeration cycle device belongs to the weak group, the determining means determines the threshold to be the upper threshold, and the refrigeration cycle device If the air conditioning intensity belongs to the strong group, the determining means determines the threshold value to be a lower threshold value that is lower than the upper threshold value.

According to the above, as the battery discharge progresses due to operation of the refrigeration cycle device,
When the battery voltage drops below a threshold, the refrigeration cycle stops. Since this threshold value is determined according to the air conditioning intensity of the refrigeration cycle device, it is suitable for the air conditioning intensity of the refrigeration cycle device. Therefore, if the refrigeration cycle device is stopped when the voltage of the battery drops to the threshold value, over-discharge of the battery is prevented when the refrigeration cycle device is stopped, regardless of the strength of the refrigeration cycle device.

According to the present invention, over-discharge of the battery is prevented when the refrigeration cycle device is stopped, regardless of the strength of the refrigeration cycle device.

It is a side view of a freight vehicle. FIG. 2 is a block diagram of a cooling device. It is a drawing of the operation panel of the air conditioner. It is a flowchart showing the flow of processing of the control unit during operation of the refrigeration cycle of the cooling device. 12 is a flowchart showing the flow of processing by the control unit when the cooling intensity of the refrigeration cycle of the cooling device is in the high level or in the middle level. 3 is a graph showing changes in battery voltage as battery discharge progresses.

Embodiments of the present invention will be described below with reference to the drawings. However, since the embodiments described below are subject to various technically preferable limitations for carrying out the present invention, the scope of the present invention is not limited to the following embodiments and illustrated examples.

<1. Overview of freight vehicles and cooling equipment>
FIG. 1 is a side view showing the rear part of a cab 2 of a freight vehicle 1 in a broken state. A chassis 3 of the truck 1 is connected to the back of the cab 2, a loading platform 4 of the truck 1 is mounted on the chassis 3, and a battery 5 of the truck 1 is attached to the front and rear center sides of the chassis 3. There is. The battery 5 is charged by an alternator driven by the engine of the truck 1 when the engine is operating. The rated voltage of the battery 5 is 24 [V]. The battery 5 may be a single battery or may be composed of a plurality of batteries connected in series or in parallel.

A cooling device 10 as an air conditioner is attached to the rear part of the cab 2 in the driver's cabin.
Note that the mounting position of the cooling device 10 is not limited to the rear part of the driver's cab, and may be mounted, for example, on the ceiling.

The cooling device 10 is connected to the positive and negative electrodes of the battery 5 via a power supply line 6 . The cooling device 10 is operated by receiving power from the battery 5 via the power supply line 6. Furthermore, the cooling device 10 is connected to the positive and negative electrodes of the battery 5 via a signal line 7 in order to measure the voltage of the battery 5 .

The cooling device 10 is mainly used and operated when the engine of the truck 1 is stopped, that is, when the battery 5 is not being charged. If the cooling device 10 is operated while the battery 5 is not being charged, the battery 5 will be discharged, so the voltage of the battery 5,
CCA (Cold Cranking Ampere) and charging rate gradually decrease. However, the cooling device 10 may be operated while the engine of the freight vehicle 1 is operating, but in this case, the battery 5 is charged, so the voltage, CCA (Cold Cranking Ampere), and charging rate of the battery 5 decrease. do not.

<2. Cooling device>
FIG. 2 is a block diagram of the cooling device 10.
The cooling device 10 in operation cools the driver's cabin of the cab 2. The cooling device 10 includes a refrigeration cycle device 20, a power conversion circuit 30, drive circuits 31 and 32, a temperature sensor 40, and an operation panel 50.
and a control section 80.

<2.1 Refrigeration cycle device>
The refrigeration cycle device 20 is operated by power from the battery 5. Refrigeration cycle device 2
0 transfers the heat from the inside air to the outside air through a refrigerant refrigeration cycle between the air inside the driver's cab of cab 2 (hereinafter referred to as "inside air") and the air outside the driver's cab (hereinafter referred to as outside air). The driver's cabin is cooled by moving the

The refrigeration cycle device 20 includes a compressor 21, a heat exchanger 22, an expansion valve 23, a heat exchanger 24, an outside air fan 25, and an inside air fan 26.

The compressor 21 is an electric compressor that compresses refrigerant. The compressor 21 includes a motor, a compressor main body that compresses refrigerant by being driven by the motor,
has. The compressor 21 operates by receiving power from the battery 5 via the power conversion circuit 30.

The compressor 21 circulates the refrigerant in the order of the compressor 21, the heat exchanger 22, the expansion valve 23, the heat exchanger 24, and the compressor 21 by compressing the refrigerant. Also,
The compressor 21 compresses the low-temperature, low-pressure gaseous refrigerant sent from the heat exchanger 24, thereby changing the refrigerant into a high-temperature, high-pressure gaseous state. The high temperature and high pressure refrigerant is sent from the compressor 21 to the heat exchanger 22.

Heat exchanger 22 is a condenser. The heat exchanger 22 exchanges heat between the high-temperature, high-pressure refrigerant sent from the compressor 21 and the outside air sent from outside the driver's cab. As a result, the refrigerant is condensed into a low-temperature, high-pressure liquid, and the outside air absorbs the heat of the refrigerant and is heated. The low-temperature, high-pressure refrigerant is sent from the heat exchanger 22 to the expansion valve 23 .

The expansion valve 23 expands the low temperature and high pressure refrigerant sent from the heat exchanger 22.
It changes the refrigerant into a low-temperature, low-pressure gas-liquid mixture that is easily vaporized. The low-temperature, low-pressure refrigerant is sent from the expansion valve 23 to the heat exchanger 24 . Note that the capillary tube is connected to the expansion valve 2.
It may be used as 3.

Heat exchanger 24 is an evaporator. The heat exchanger 24 exchanges heat between the low-temperature, low-pressure refrigerant sent from the expansion valve 23 and the internal air sent from inside the driver's cab. As a result, the refrigerant absorbs heat from the inside air and vaporizes, thereby cooling the inside air. The low-temperature, low-pressure gaseous refrigerant is sent from the heat exchanger 24 to the compressor 21 .

The outside air fan 25 receives power from the battery 5 via the drive circuit 31 and operates. The outside air fan 25 blows outside air to the heat exchanger 22 and discharges the outside air heated by the heat exchanger 22 to the outside of the driver's cab.

The inside air fan 26 receives power from the battery 5 via the drive circuit 32 and operates. The inside air fan 26 blows inside air to the heat exchanger 24 and discharges the inside air cooled by the heat exchanger 24 to the inside of the driver's cab.

<2.2 Power conversion circuit and drive circuit>
The power conversion circuit 30 converts the DC power output from the battery 5 into driving power that can drive the compressor 21, and outputs the driving power to the compressor 21. This results in
Power conversion circuit 30 drives compressor 21 . The power conversion circuit 30 is, for example, an inverter device, a DC/DC converter, or a switching regulator.

The drive circuit 31 converts the DC power output from the battery 5 into drive power that can drive the outside air fan 25, and outputs the drive power to the outside air fan 25. Thereby, the drive circuit 31 drives the outside air fan 25. The drive circuit 32 converts the DC power output from the battery 5 into driving power that can drive the inside air fan 26, and uses the driving power to drive the inside air fan 2.
Output to 6. Thereby, the drive circuit 31 drives the inside air fan 26. Drive circuit 3
1 and 32 are, for example, DC/AC converters, DC/DC converters, or switching converters.
It is a regulator.

<2.3 Temperature sensor>
The temperature sensor 40 measures the temperature in the driver's cabin of the cab 2 and outputs a signal representing the measured temperature to the control unit 80.

<2.4 Control section>
The control unit 80 includes a computer having a CPU, memory, and the like.
The control unit 80 is connected to the positive and negative electrodes of the battery 5 via the signal line 7 . The control unit 80 detects the voltage of the battery 5.

The control unit 80 controls the operating speed of the compressor 21 in four stages: a strong stage, a medium stage, a weak stage, and a stop stage by controlling the power conversion circuit 30. The operating speed of the compressor 21 increases in the order of strong stage, middle stage, and weak stage, and the compressor 21 stops at the stop stage.

The control unit 80 controls the outside air fan 25 by individually controlling the drive circuits 31 and 32.
The operating speed of the internal air fan 26 is individually controlled in four stages: strong stage, medium stage, weak stage, and stop stage. The operating speeds of the outside air fan 25 and the inside air fan 26 increase in the order of strong stage, middle stage, and weak stage, and in the stop stage, the outside air fan 25 and the inside air fan 26 stop.

The control unit 80 controls the cooling intensity of the refrigeration cycle device 20 by individually controlling the operating speeds of the compressor 21, the outside air fan 25, and the inside air fan 26. Specifically, the control unit 80 controls the cooling intensity of the refrigeration cycle device 20 to the high level by operating the compressor 21, the outside air fan 25, and the internal air fan 26 at the high level of operating speed. The control unit 80 controls the cooling intensity of the refrigeration cycle device 20 to a medium level by operating the compressor 21, the outside air fan 25, and the internal air fan 26 at a medium speed. The control unit 80 includes a compressor 21, an outside air fan 25, and an inside air fan 2.
6 at the operating speed in the weak stage, the cooling intensity of the refrigeration cycle device 20 is controlled to the weak stage. The control unit 80 stops the compressor 21 and the outside air fan 25,
In addition, by operating the inside air fan 26 at a low operating speed, the cooling intensity of the refrigeration cycle device 20 is controlled to the ventilation stage. The power consumption of the refrigeration cycle device 20 is in a strong stage,
Medium stage, weak stage, and ventilation stage are the highest in order.

The control unit 80 stores the current stage of the cooling intensity of the refrigeration cycle device 20 in the memory while the refrigeration cycle device 20 is in operation.

For example, the cooling intensity level of the refrigeration cycle device 20 can be divided into a strong group with high intensity and a weak group with lower intensity. In this case, the above-mentioned strong stage and middle stage belong to the strong group, and the weak stage and the ventilation stage belong to the weak group.

<2.4.1 Control mode of control unit>
As described above, the cooling intensity of the refrigeration cycle device 20 has strong stages, medium stages, weak stages, and ventilation stages, but there are variations in how to set the cooling strength. Hereinafter, the method of setting the cooling intensity will be referred to as a control mode of the control unit 80.

Variations of the control mode of the control unit 80 include an energy saving control mode, an automatic intensity setting control mode, and a manual intensity setting control mode. The control mode of the control unit 80 can be manually selected from among an energy saving control mode, an automatic intensity setting control mode, and a manual intensity setting control mode. The operation panel 50 is used for manual selection. Regarding the operation panel 50,
This will be explained in detail later.

<2.4.1.1 Energy saving control mode>
In the energy saving control mode, the control unit 80 operates the compressor 21, the outside air fan 25, and the inside air fan 26 at a low speed, and controls the cooling intensity of the refrigeration cycle device 20 to a low speed. In the energy saving control mode, the control unit 80 manually presses the cooling intensity change button 5.
The cooling intensity of the refrigeration cycle device 20 is forcibly controlled to the weak stage, ignoring the operations in steps 5 and 56. Since the cooling intensity when the occupant sleeps at night often needs to be lower than the cooling intensity required during the day, the energy saving control mode is to operate the refrigeration cycle device 20 in the low stage for a long time. It is set for the purpose of

When the control mode of the control unit 80 is the energy saving control mode, the control unit 80 stores in the memory that the current control mode is the energy saving control mode.

<2.4.1.2 Automatic intensity setting control mode>
In the automatic intensity setting control mode, the control unit 80, based on the temperature measured by the temperature sensor 40,
The cooling intensity stage of the refrigeration cycle device 20 is selected from among the strong stage, medium stage, weak stage, and ventilation stage, and the cooling strength of the refrigeration cycle device 20 is controlled to the selected stage.

Specifically, the control unit 80 calculates the difference obtained by subtracting the set temperature from the measured temperature of the temperature sensor 40 to a first threshold, a second threshold, and a third threshold (however, the first threshold, the second threshold, and the third threshold are " First threshold>
The relationship is "second threshold>third threshold". ). As a result of the comparison, if the difference is greater than or equal to the first threshold, the control unit 80 operates the compressor 21 and the outside air fan 2 at the high operating speed.
5 and the inside air fan 26, the cooling intensity of the refrigeration cycle device 20 is controlled to a high level. As a result of the comparison, if the difference is greater than or equal to the second threshold and less than the first threshold, the control unit 80 operates the compressor 21, the outside air fan 25, and the inside air fan 26 at an intermediate operating speed, The cooling intensity of the refrigeration cycle device 20 is controlled to a medium level. As a result of the comparison, if the difference is greater than or equal to the third threshold and less than the second threshold, the control unit 80 operates the compressor 21, the outside air fan 25, and the inside air fan 26 at a low operating speed,
The cooling intensity of the refrigeration cycle device 20 is controlled to a weak level. As a result of the comparison, if the difference is less than the third threshold, the control unit 80 stops the compressor 21 and the outside air fan 25, and operates the inside air fan 26 at a low operating speed. The cooling intensity of the cycle device 20 is controlled to the ventilation stage. Note that the set temperature can be manually increased or decreased using the operation panel 50, and the increase or decrease in the set temperature will be described later.

When the control mode of the control section 80 is the automatic intensity setting control mode, the control section 80 stores in the memory that the current control mode is the automatic intensity setting control mode.

<2.4.1.3 Manual strength setting control mode>
In the manual intensity setting control mode, the control unit 80 controls the cooling intensity of the refrigeration cycle device 20 to a manually selected level from among a strong level, a medium level, a weak level, and a blowing level. The operation panel 50 is used for manual stage selection. The operation panel 50 will be explained in detail later.

When the control mode of the control unit 80 is the manual intensity setting control mode, the control unit 80 stores in the memory that the current control mode is the manual intensity setting control mode.

<2.5 Operation panel>
The operation panel 50 is operated by a passenger and outputs a signal to the control unit 80 according to the operation content. The operation panel 50 is used by the occupant to manually select the control mode of the control unit 80 from among the energy saving control mode, automatic intensity setting control mode, and manual intensity setting control mode. The operation panel 50 is used by the occupant to manually change the set temperature in the automatic intensity setting control mode. The operation panel 50 is used by an occupant to manually change the cooling intensity level of the refrigeration cycle device 20 in the manual intensity setting control mode.

FIG. 3 is a drawing showing an example of the operation panel 50. As shown in FIG. The operation panel 50 includes a cooling operation start button 58, an energy saving setting button 51, set temperature change buttons 52 and 53, and a set temperature display section 5.
4. It has cooling intensity change buttons 55, 56 and a cooling intensity display section 57.

<2.5.1 Cooling operation start button>
The cooling operation start button 58 is a button for starting cooling operation. When the occupant presses the cooling operation start button 58, the cooling operation start button 58 outputs a signal to the control unit 80. When a signal is input from the cooling operation start button, the control unit 80 starts operating the refrigeration cycle device 20 in the automatic intensity operation mode.

<2.5.2 Energy saving setting button>
The energy saving setting button 51 is a button for turning on/off the energy saving control mode. When the occupant presses the energy saving setting button 51 while the control mode of the control unit 80 is the automatic intensity setting control mode or the manual intensity setting control mode, the energy saving setting button 51 outputs a signal to the control unit 80, and the signal is output to the control unit 80. Upon receiving the input, the control unit 80 switches the control mode from the automatic intensity setting control mode or the manual intensity setting control mode to the energy saving setting control mode. When the occupant presses the energy saving setting button 51 while the control mode of the control unit 80 is the energy saving control mode, the energy saving setting button 51 outputs a signal to the control unit 80, and the control unit 8 that inputs the signal
0 switches the control mode from the energy saving control mode to the automatic intensity setting control mode.

<2.5.3 Set temperature change button>
The set temperature change button 52 is for incrementing the set temperature. When the occupant presses the set temperature change button 52, the set temperature change button 52 outputs a signal to the control unit 80. The control unit 80 increments the set temperature when a signal is input from the set temperature change button 52.

The set temperature change button 53 is for decrementing the set temperature. When the occupant presses the set temperature change button 53, the set temperature change button 53 outputs a signal to the control unit 80. When a signal is input from the set temperature change button 53, the control unit 80 decrements the set temperature.

Note that when the control mode of the control unit 80 is the automatic intensity setting control mode, when the set temperature change button 52 or 53 is pressed, the control unit 80 maintains the control mode in the automatic intensity setting control mode, and then As described above, the control unit 80 compares the difference obtained by subtracting the incremented or decremented set temperature from the temperature measured by the temperature sensor 40 with the first threshold, the second threshold, and the third threshold. When the control mode of the control unit 80 is the manual intensity setting control mode, when the set temperature change button 52 or 53 is pressed, the control unit 80 switches the control mode from the manual intensity setting control mode to the automatic intensity setting control mode. Then, as described above, the control unit 80 compares the difference obtained by subtracting the incremented or decremented set temperature from the measured temperature of the temperature sensor 40 with the first threshold, the second threshold, and the third threshold. When the control mode of the control section 80 is the energy saving control mode, when the set temperature change button 52 or 53 is pressed, the control section 80 maintains the control mode in the energy saving control mode and then changes the set temperature. Increment or decrement.

<2.5.4 Set temperature display section>
The set temperature display section 54 is a dot matrix display or a segment display. The set temperature display section 54 displays the set temperature.

<2.5.5 Cooling intensity change button>
When the occupant presses the cooling intensity change button 55, the cooling intensity change button 55 outputs a signal to the control unit 80. When the occupant presses the cooling intensity change button 56, the cooling intensity change button 56
outputs a signal to the control section 80.

The cooling intensity change button 55 is used to increment the cooling intensity level of the refrigeration cycle device 20 when the control mode of the control unit 80 is the manual intensity setting control mode or the automatic intensity setting control mode. When the control mode of the control unit 80 is the manual intensity setting control mode, when a signal is input to the control unit 80 from the cooling intensity change button 55, the control unit 80 maintains the control mode in the manual intensity setting control mode and then changes the control mode to the manual intensity setting control mode. Then, the cooling intensity level of the refrigeration cycle device 20 is incremented. When the control mode of the control unit 80 is the automatic intensity setting control mode, when a signal is input to the control unit 80 from the cooling intensity change button 55, the control unit 80 changes the control mode from the automatic intensity setting control mode to the manual intensity setting. After switching to the control mode, the cooling intensity level of the refrigeration cycle device 20 is incremented.

The cooling intensity change button 56 is for decrementing the cooling intensity level of the refrigeration cycle device 20 when the control mode of the control unit 80 is the manual intensity setting control mode or the automatic intensity setting control mode. When the control mode of the control unit 80 is the manual intensity setting control mode, when a signal is input to the control unit 80 from the cooling intensity change button 56, the control unit 80 maintains the control mode in the manual intensity setting control mode and then changes the control mode to the manual intensity setting control mode. Then, the cooling intensity level of the refrigeration cycle device 20 is decremented. When the control mode of the control unit 80 is the automatic intensity setting control mode, when a signal is input to the control unit 80 from the cooling intensity change button 56, the control unit 80 changes the control mode from the automatic intensity setting control mode to the manual intensity setting. After switching to the control mode, the cooling intensity level of the refrigeration cycle device 20 is decremented.

Note that when the control mode of the control unit 80 is the energy saving control mode, even if a signal is input to the control unit 80 from the cooling intensity change buttons 55 and 56, the control unit 80 maintains the control mode in the energy saving control mode and , the cooling intensity level of the refrigeration cycle device 20 is maintained at the weak level.

<2.5.6 Cooling intensity display section>
The cooling intensity display section 57 is an indicator consisting of a plurality of LEDs. Cooling intensity display section 5
7 displays the cooling intensity level of the refrigeration cycle device 20.

<3. Over-discharge prevention function of cooling equipment>
When the refrigeration cycle device 20 is operated while the engine of the freight vehicle 1 is stopped, the battery 5 is discharged, and the voltage, CCA, and charging rate of the battery 5 are reduced. If the refrigeration cycle device 20 is operated until the battery 5 is over-discharged, the CCA and charging rate of the battery 5 will drop too much, and the capacity of the battery 5 will drop excessively to the extent that the engine of the truck 1 cannot be started. . Therefore, in order to prevent the battery 5 from becoming over-discharged, the cooling device 10 has an over-discharge prevention function.

The overdischarge prevention function of the cooling device 10 is realized by the following process (1) of the control unit 80 while the refrigeration cycle device 20 is operating. The control mode of the control unit 80 is an energy saving control mode,
In both the automatic strength setting control mode and the manual strength setting control mode, the control unit 80 executes the following process (1). In addition, the cooling intensity of the refrigeration cycle device 20 is set to high level, medium level,
In both the weak stage and the blowing stage, the control unit 80 executes the following process (1).

<3.1 Processing (1)>
FIG. 4 is a flowchart showing the flow of process (1) executed by the control unit 80.
First, the control section 80 functions as a voltage detection means (step S1). The voltage detection means is
The voltage of the battery 5 is detected via the signal line 7.

Next, the control section 80 functions as a recognition means (step S2). The recognition means recognizes the cooling intensity of the refrigeration cycle device 20 from the contents stored in the memory.

Next, the control unit 80 functions as a determining means (step S3). The determining means determines the threshold value according to the cooling intensity of the refrigeration cycle device 20 recognized in step S2. For example, when the cooling intensity of the refrigeration cycle device 20 is at the strong level or the middle level, which belongs to the strong group, the determining means determines the threshold to be the lower threshold, and the cooling intensity of the refrigeration cycle device 20 belongs to the weak group. In the case of the weak stage or the ventilation stage, the determining means determines the threshold value to be an upper threshold value higher than the lower threshold value. The values of the upper threshold value and the lower threshold value are not particularly limited as long as the voltage is such that the battery 5 can start the engine of the freight vehicle 1. For example, the upper threshold value and the lower threshold value are lower than the rated voltage of the battery 5, More specifically, the upper and lower thresholds are each 23.5 [V
], 23.3 [V], 23.7 [V] and 23.5 [V], respectively, or 24.0 [V] and 23.8 [V], respectively. Note that before the process (1) is executed, the setting values of the upper threshold value and the lower threshold value are set to 0.1, for example, by the operator operating the operation panel 50.
It may be changed in [V] increments, or the set values of the upper threshold value and the lower threshold value may be determined from among the numerical values listed above. Alternatively, the upper threshold value and the lower threshold value may be fixed to any of the numerical values listed above.

Next, the control section 80 functions as a comparison means. The comparison means compares the voltage of the battery 5 detected in step S1 with the threshold determined in step S3 (step S4).

As a result of the comparison in step S4, if the voltage of the battery 5 is higher than the threshold (step S4
:No), the control unit 80 returns the process to step S1, and the control unit 80 executes steps S1 to S4.
Execute the process again. Therefore, the control unit 80 repeatedly executes the processes of steps S1 to S4 and continues to operate the refrigeration cycle device 20 until the voltage of the battery 5 becomes equal to or less than the threshold value.

As a result of the comparison in step S4, if the voltage of the battery 5 is below the threshold value (step S4:
(Yes), the control unit 80 moves the process to step S5. In step S5, the control unit 80
functions as a stopping means. The stopping means stops the refrigeration cycle device 20 by stopping the compressor 21, the outside air fan 25, and the inside air fan 26. Therefore, the power of the battery 5 is not consumed, and over-discharge of the battery 5 is prevented.

When the refrigeration cycle device 20 stops, the control unit 80 ends the process.
Note that the timing at which the control unit 80 detects the voltage of the battery 5 as a voltage detection means is as follows.
Any time is acceptable as long as it is before step S4. For example, step S2 or step S3
The control unit 80 may detect the voltage of the battery 5 later.

<3.2 Verification>
When the refrigeration cycle device 20 is operated at high cooling intensity until the voltage of a fully charged new battery 5 drops to the lower threshold value (=23.3 [V]), the current value at the terminals of the battery 5 and The time required for the voltage of the battery 5 to drop to the lower threshold value, and the CCA and charging rate of the battery 5 when the voltage of the battery 5 reaches the lower threshold value were investigated through experiments.

In addition, when the refrigeration cycle device 20 is operated at a low level of cooling intensity until the voltage of a fully charged new battery 5 drops to the lower threshold value (=23.3 [V]), the current at the terminals of the battery 5 The value, the time until the voltage of the battery 5 drops to the lower threshold value, and the CCA and charging rate of the battery 5 when the voltage of the battery 5 reaches the lower threshold value were investigated through experiments.

The experimental results are shown in Table 1.

As is clear from Table 1, the CCA of the battery 5 and the It can be seen that the charging rate decreases further. As can be seen from such experimental results, when the refrigeration cycle device 20 is operated at the cooling intensity of the weak stage or the blowing stage, the voltage of the battery 5 reaches the upper threshold value as in the above process (1). When the control unit 80 stops the refrigeration cycle device 20, over-discharging of the battery 5 is prevented. On the other hand, when the refrigeration cycle device 20 is operated at a high or medium cooling intensity, as in the above process (1),
When the voltage of the battery 5 reaches the lower threshold value, which is lower than the upper threshold value, the control unit 80 stops the refrigeration cycle device 20, which not only prolongs the operation time of the refrigeration cycle device 20 but also prevents the battery 5 from being over-discharged. is prevented.

<4. Cooling device operating time extension function>
When the refrigeration cycle device 20 is operated in the strong stage or middle stage of the automatic strength setting control mode and the manual strength setting control mode while the engine of the freight vehicle 1 is stopped, the battery 5 is quickly discharged, and the operation of the refrigeration cycle device 20 is interrupted. The available time is short. Therefore, in order to extend the operating time of the refrigeration cycle device 20, the cooling device 10 has an operating time extension function.

The operation time extension function of the cooling device 10 is realized by the following process (2) of the control unit 80 while the refrigeration cycle device 20 is operating. Note that when the cooling intensity of the refrigeration cycle device 20 is in the strong stage or medium stage in the automatic strength setting control mode and the manual strength setting control mode,
The control unit 80 executes the following process (2), but when the cooling intensity of the refrigeration cycle device 20 is at the low level or the ventilation level, the control unit 80 does not execute the following process (2). In addition, the control unit 8
0 may execute process (2) in parallel with process (1) above, or process (1) above.
Process (2) may be executed without performing.

<4.1 Processing (2)>
FIG. 5 is a flowchart showing the flow of process (2) executed by the control unit 80.
First, the control section 80 functions as a voltage detection means (step S21). The voltage detection means detects the voltage of the battery 5 via the signal line 7.

Next, the control section 80 functions as a comparison means (step S22). The comparison means compares the voltage of the battery 5 detected in step S21 with a predetermined threshold value. The value of the predetermined threshold value is not particularly limited as long as the voltage is such that the battery 5 can start the engine of the freight vehicle 1. For example, the predetermined threshold value is lower than the rated voltage of the battery 5, and more specifically, The threshold value is equal to the above-mentioned upper threshold value, and is 23.5 [V], 23.7 [V] or 24.0 [V].
].

As a result of the comparison in step S22, if the voltage of the battery 5 is higher than the predetermined threshold (step S22: No), the control unit 80 returns the process to step S21, and the control unit 80 re-executes the processes in steps S21 to S22. do. Therefore, the control unit 80 repeatedly executes the processing of steps S21 and S22 until the voltage of the battery 5 becomes equal to or less than the processing threshold, and
The operation of the refrigeration cycle device 20 is continued at the strong stage or the middle stage.

As a result of the comparison in step S22, if the voltage of the battery 5 is equal to or lower than the predetermined threshold (step S22: Yes), the control unit 80 moves the process to step S23. In step S23, the control section 80 functions as a switching means. The switching means switches the cooling intensity of the refrigeration cycle device 20 to the weak stage by switching the operating speeds of the compressor 21, the outside air fan 25, and the inside air fan 26 to the weak stage.

When the cooling intensity of the refrigeration cycle device 20 is switched to the weak stage, the control unit 80 ends the process and continues the operation of the refrigeration cycle device 20 at the low stage. Such a low level of cooling intensity may be a low level in the energy saving control mode, or may be a low level in the manual intensity setting control mode.

When the cooling intensity of the refrigeration cycle device 20 is switched from the strong stage or the middle stage to the weak stage in step S23, the voltage of the battery 5 increases, so that the operating time of the refrigeration cycle device 20 is extended.

Further, when the cooling intensity of the refrigeration cycle device 20 is switched to the weak stage in step S23, the occupant notices this. This triggers the occupant to notice that the remaining capacity of the battery 5 is decreasing. Then, the occupant can start the engine to restore the remaining capacity of the battery 5, thereby preventing the battery 5 from being over-discharged.

Further, after the cooling intensity of the refrigeration cycle device 20 is switched to the weak stage in step S23, if a stronger cooling intensity than the weak stage is required even for a short time, the occupant operates the operation panel 50. Specifically, when the stage after switching in step S23 is a weak stage in the energy saving control mode, when the occupant presses the energy saving setting button 51, the control unit 80 changes the control mode from the energy saving control mode to the automatic intensity setting control mode. At the same time, comfort is maintained because the cooling intensity of the refrigeration cycle device 20 is returned to the cooling intensity before switching to the low level. If the stage after switching in step S23 is a weak stage in the manual strength setting control mode, when the occupant presses the cooling strength change button 55, the control unit 80 controls the refrigeration cycle device 20.
Comfort is maintained by increasing the cooling intensity. In this way, after the occupant switches the cooling intensity of the refrigeration cycle device 20 from the weak stage to the medium stage or strong stage by operating the operation panel 50, the threshold determined in step S3 becomes the lower threshold, so that the battery 5 is not overloaded. Discharge can be prevented.

Note that if the control unit 80 executes process (1) in parallel with process (2), step S2
After the cooling intensity of the refrigeration cycle device 20 is switched from the strong stage or middle stage to the weak stage in step S3, when the voltage of the battery 5 becomes equal to or lower than the upper threshold value (step S4: Yes), the control unit 80 functioning as a stopping means, Compressor 21, outside air fan 25, and inside air fan 2
6, the refrigeration cycle device 20 is stopped (step S5). This prevents over-discharging of the battery 5.

<4.2 Verification>
After the refrigeration cycle device 20 is operated at the high level cooling intensity until the voltage of the fully charged battery 5 drops to a predetermined threshold value (=23.5 [V]), the cooling intensity of the refrigeration cycle device 20 is changed to the high level. The change in the voltage of the battery 5 was experimentally investigated when switching from the low stage to the low stage. The experimental results are shown in the graph of FIG.

As is clear from FIG. 6, when the refrigeration cycle device 20 is operated at the high cooling intensity level, the voltage of the battery 5 gradually decreases. When about 2 hours and 40 minutes have passed since the start of operation, the voltage of the battery 5 drops to a predetermined threshold value. Then, when the cooling intensity of the refrigeration cycle device 20 switches from the strong stage to the weak stage, the voltage of the battery 5 rises from the predetermined threshold value. Therefore, the operating time of the refrigeration cycle device 20 is extended by the time until the voltage of the battery 5 falls to the predetermined threshold again.

<5. Modified example>
Modifications of the above-described embodiment will be described below. At least two changes described below may be applied in combination.

(1) In the above-described embodiment, in step S23, the control unit 80 functioning as a switching unit switches the cooling intensity of the refrigeration cycle device 20 from a strong level or a medium level to a weak level. On the other hand, the control unit 80 may switch the cooling intensity of the refrigeration cycle device 20 from a high level or a medium level to a blowing level.

(2) In the above-described embodiment, in step S3, when the cooling intensity of the refrigeration cycle device 20 is at the strong stage or the middle stage (belonging to the strong group), the control unit 80 functioning as a determining means sets the threshold value. When the lower threshold value is determined and the cooling intensity of the refrigeration cycle device 20 is at the weak stage or the ventilation stage (the stage belonging to the weak group), the control unit 80 determines the threshold value to be the upper threshold value. On the other hand, in step S3, the cooling intensity of the refrigeration cycle device 20 is set to a high level (
If the cooling intensity of the refrigeration cycle device 20 is in the middle stage, weak stage, or ventilation stage (belonging to the weak group), the control unit 80 functioning as a determining means determines the threshold value to be the lower threshold value. step), the control unit 80 may determine the threshold to be the upper threshold. Alternatively, in step S3, when the cooling intensity of the refrigeration cycle device 20 is in the strong stage, middle stage, or weak stage (belonging to the strong group), the control unit 80 functioning as a determining means determines the threshold value to be the lower threshold value. However, when the cooling intensity of the refrigeration cycle device 20 is at the ventilation stage (the stage belonging to the weak group), the control unit 80 may determine the threshold value to be the upper threshold value.

(3) In the embodiment described above, there are four levels of cooling intensity of the refrigeration cycle device 20.
The cooling intensity level of the refrigeration cycle device 20 is not limited to this, as long as it is two or more levels, for example, it may be two levels, a strong level and a weak level, or it may be three levels, five levels, or more. It may be at this stage.

(4) In the above-described embodiment, in step S3, the control unit 8 functioning as a determining means
When 0 determines the threshold value, a threshold value is assigned to each of the strong group and weak group. On the other hand, a threshold value may be assigned to each level of cooling intensity of the refrigeration cycle device 20. In this case, the higher the level of cooling intensity of the refrigeration cycle device 20, the lower the assigned threshold value. That is, in step S3, when the cooling intensity of the refrigeration cycle device 20 is at the high level, the control unit 80 functioning as a determining means determines the lowest threshold value, and the cooling intensity of the refrigeration cycle device 20 is at the medium level. In this case, the control unit 80 determines the second lowest threshold value, and if the cooling intensity of the refrigeration cycle device 20 is in the weak stage, the control unit 80 determines the second lowest threshold value.
is determined to be the third lowest threshold value, and when the cooling intensity of the refrigeration cycle device 20 is at the ventilation stage, the control unit 80 determines the highest threshold value.

(5) In the embodiments described above, air conditioning is mentioned as an example of air conditioning, and the air conditioner 10 is mentioned as an example of an air conditioner. On the other hand, the cooling device 10 may be changed to a heating device. In this case, the term "cooling" in the description of the cooling device 10 is replaced with the term "heating." Further, the flow direction of the refrigerant in the refrigeration cycle device 20 is reversed, the heat exchanger 22 is an evaporator, and the heat exchanger 24 is a condenser.

(6) In the above embodiment, the cooling device 10 is mentioned as an example of the air conditioner. On the other hand, the cooling device 10 may be changed to an air conditioner that can switch between cooling and heating. In this case, compressor 21 is connected to the four-way valve, and heat exchanger 22 and heat exchanger 24 are connected to the four-way valve. During cooling, the control unit 80 controls the four-way valve, so that the four-way valve changes the flow direction of the refrigerant from the heat exchanger 24 (the heat exchanger 24 is an evaporator) to the compressor 21. to switch the direction toward the heat exchanger 22 (heat exchanger 22 is a condenser). On the other hand, during heating, the control unit 80 controls the four-way valve, so that the four-way valve changes the flow direction of the refrigerant from the heat exchanger 22 (the heat exchanger 22 is an evaporator) to the compressor 21. via the heat exchanger 24 (the heat exchanger 24 is a condenser).

(7) In step S3 described above, the control unit 80 as a determining means may determine the threshold value as follows. That is, when the cooling intensity of the refrigeration cycle device 20 is in the high level or medium level belonging to the strong group, the control unit 80 as a determining means determines the threshold value to be the lower threshold value. Even if the cooling intensity of the refrigeration cycle device 20 is in the weak stage or the ventilation stage belonging to the weak group, from the time the cooling intensity of the refrigeration cycle device 20 switches from the high stage or medium stage to the weak stage or the ventilation stage. If the predetermined time (for example, 5 minutes) has not elapsed, the control unit 80 as a determining means determines the threshold value to be the lower threshold value. When the cooling intensity of the refrigeration cycle device 20 is in the weak stage or the ventilation stage belonging to the weak group, and the cooling intensity of the refrigeration cycle device 20 is switched from the strong stage or medium stage to the weak stage or the ventilation stage, the predetermined time (e.g. 5 minutes)
If the time has elapsed, the control unit 80 as a determining means determines the threshold to be an upper threshold that is higher than the lower threshold. In addition, in order to realize this, the control unit 80 starts timing when the cooling intensity of the refrigeration cycle device 20 is switched from the strong stage or medium stage to the weak stage or ventilation stage.

<6. Beneficial effects＞
(1) As explained above, the cooling device 10 according to the present embodiment includes a refrigeration cycle device 20 that air-conditions the driver's cab of the freight vehicle 1 by being driven by the electric power of the battery 5; A control unit 80 that controls the air conditioning intensity in stages is provided. The control unit 80 includes a determining means (step S
3), a comparison means (step S4) that compares the voltage of the battery 5 with the threshold determined by the determination means (step S3), and a comparison means (step S4) that determines that the voltage of the battery 5 is below the threshold. In some cases (step S4: Yes), a stopping means (step S5) is provided to stop the refrigeration cycle device 20.
In such a cooling device 10, since the threshold value is determined according to the air conditioning intensity of the refrigeration cycle device 20, the threshold value is suitable for the air conditioning intensity of the refrigeration cycle device 20. Therefore, if the refrigeration cycle device 20 is stopped when the voltage of the battery 5 drops to the threshold value, over-discharge of the battery 5 when the refrigeration cycle device 20 is stopped is prevented regardless of the air conditioning strength of the refrigeration cycle device 20.

(2) In the cooling device 10 according to the present embodiment, if the air conditioning intensity of the refrigeration cycle device 20 is in the weak stage or ventilation stage belonging to the weak group, the determining means (step S3) determines the threshold to be the upper threshold, and If the air conditioning intensity of the cycle device 20 is at the strong level or medium level belonging to the strong group, the determining means (step S3) determines the threshold value to be the lower threshold value.
In this way, when the refrigeration cycle device 20 is operated at the air conditioning intensity of the weak stage or the ventilation stage, the stopping means (step S5) stops the refrigeration cycle device 20 when the voltage of the battery 5 reaches the upper threshold value. This prevents the battery 5 from being over-discharged. On the other hand, when the refrigeration cycle device 20 is operated at a strong or medium air conditioning intensity level, the stopping means (step S5) stops the refrigeration cycle device 20 when the voltage of the battery 5 reaches the lower threshold value. In addition, the operation time of the refrigeration cycle device 20 becomes long, and over-discharge of the battery 5 is prevented.

(3) In the cooling device 10 according to the present embodiment, if the air conditioning intensity of the refrigeration cycle device 20 is in the strong stage or middle stage belonging to the strong group, the determining means (step S3) determines the threshold value to be the lower threshold value, and The air conditioning intensity of the cycle device 20 is in the weak stage or the ventilation stage belonging to the weak group, and a predetermined period of time has elapsed since the air conditioning strength of the refrigeration cycle device 20 was switched from the strong stage or medium stage to the weak stage or the ventilation stage. If so, the determining means (step S3) determines the threshold value to be the upper threshold value, and the air conditioning intensity of the refrigeration cycle device 20 is in the weak stage or the ventilation stage, and the air conditioning strength of the refrigeration cycle device 20 is in the strong stage or medium stage. If a predetermined period of time has not elapsed since the stage was switched to the weak stage or the ventilation stage, the determining means (step S3) determines the threshold value to be the lower threshold value.
In this way, when the refrigeration cycle device 20 is operated at the high or medium air conditioning intensity,
When the voltage of the battery 5 reaches the lower threshold value, the stopping means (step S5) stops the refrigeration cycle device 20, which not only lengthens the operating time of the refrigeration cycle device 20, but also
Over-discharging of the battery 5 is prevented. Until a predetermined period of time has elapsed since the air conditioning intensity of the refrigeration cycle device 20 was switched from the strong stage or medium stage to the weak stage or ventilation stage, the battery 5
Since there is a possibility that the voltage of the battery 5 does not change immediately, during that period, the stopping means (step S5) stops the refrigeration cycle device 20 when the voltage of the battery 5 reaches the lower threshold value. In addition to prolonging the operation time of the battery 20, over-discharging of the battery 5 is also prevented. After a predetermined time has elapsed since the air conditioning intensity of the refrigeration cycle device 20 was switched from the strong stage or medium stage to the weak stage or ventilation stage, when the voltage of the battery 5 reaches the upper threshold value, the stop means (step S5) When the refrigeration cycle device 20 is stopped, over-discharge of the battery 5 is prevented.

(4) In the cooling device 10 according to the present embodiment, the control unit 80 controls the refrigeration cycle device 20
a second comparing means (step S22) that compares the voltage of the battery 5 with a predetermined threshold value when the air conditioning intensity is at the strong level or the weak level belonging to the strong group;
), when the voltage of the battery 5 is below a predetermined threshold value, switching means (step S23) switches the air conditioning intensity of the refrigeration cycle device to a weak stage or a ventilation stage belonging to the weak group.
In this way, when the cooling intensity of the refrigeration cycle device 20 is switched from the strong or medium stage to the weak or ventilation stage, the voltage of the battery 5 increases. Therefore, the refrigeration cycle device 20
The operating time of is extended by the time until the voltage of battery 5 falls to the predetermined threshold again.

10...Cooling device (air conditioner)
20... Refrigeration cycle device 80... Control unit (determining means, comparing means, stopping means, second comparing means, switching means)

Claims (3)

a refrigeration cycle device that air-conditions a vehicle cab by being operated by battery power;
A control unit that controls the air conditioning intensity of the refrigeration cycle device in stages,
The control section,
determining means for determining a threshold value according to the air conditioning intensity of the refrigeration cycle device;
Comparing means for comparing the voltage of the battery with the threshold value determined by the determining means;
stopping means for stopping the refrigeration cycle device when the voltage of the battery is equal to or lower than the threshold value as a result of comparison by the comparing means ;
When the air conditioning strength level of the refrigeration cycle apparatus is divided into a strong group with high intensity and a weak group with lower intensity, if the air conditioning intensity of the refrigeration cycle apparatus belongs to the weak group, then the The determining means determines the threshold to be an upper threshold, and if the air conditioning intensity of the refrigeration cycle device belongs to the strong group, the determining means determines the threshold to be a lower threshold lower than the upper threshold.
Air conditioner. a refrigeration cycle device that air-conditions a vehicle cab by being operated by battery power;
A control unit that controls the air conditioning intensity of the refrigeration cycle device in stages,
The control section,
determining means for determining a threshold value according to the air conditioning intensity of the refrigeration cycle device;
Comparing means for comparing the voltage of the battery with the threshold value determined by the determining means;
stopping means for stopping the refrigeration cycle device when the voltage of the battery is equal to or lower than the threshold value as a result of comparison by the comparing means ;
If the air conditioning intensity level of the refrigeration cycle device is divided into a strong group with high intensity and a weak group with lower intensity, if the air conditioning intensity of the refrigeration cycle device belongs to the strong group, then The determining means determines the threshold value to be a lower threshold value, and the air conditioning intensity of the refrigeration cycle apparatus belongs to the weak group, and the air conditioning intensity of the refrigeration cycle apparatus belongs to the strong group to the weak group. If a predetermined period of time has elapsed since switching to the stage belonging to the weak group, the determining means determines the threshold value to be an upper threshold value higher than the lower threshold value, and the air conditioning intensity of the refrigeration cycle apparatus is at the stage belonging to the weak group. If the predetermined period of time has not elapsed since the air conditioning strength of the refrigeration cycle device was switched from the stage belonging to the strong group to the stage belonging to the weak group, the determining means sets the threshold value to the lower threshold value. decide on
Air conditioner. The control section,
a second comparing means for comparing the voltage of the battery with a predetermined threshold when the air conditioning strength of the refrigeration cycle device is in the strong group;
2. The method according to claim 1, further comprising a switching means for switching the air conditioning intensity of the refrigeration cycle device to a stage belonging to the weak group when the voltage of the battery is equal to or lower than the predetermined threshold as a result of the comparison by the second comparing means. 2. The air conditioner according to 2 .

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