JPS62280536A - Capacity controlling system for refrigerant compressor - Google Patents

Abstract

PURPOSE:To obtain a comfortable air cooled feeling and a smooth controlling function in an air conditioner, by designing a compressor in such a manner that its capacity is controllable, based on the time which is needed for an air-conditioned space to reach a controlled temperature. CONSTITUTION:A capacity of compressor controller 13 sets the capacity of a refrigerant compressor 9 at its maximum at the starting time, based on a signal from a setting part 12. At the time of a secondary capacity control, the capacity of a compressor is set, based on the data from a capacity of compressor arithmetic part 6. A control unit 8 is provided with a comparator.judgement unit 14 which compares to judge the outlet temperature TE of an evaporator 6 detected by a temperature sensor 7, with predetermined uppermost and lowermost temperatures TH, TL which form a comfortable temperature zone. In case that TE<TL, the refrigerant compressor 9 is stopped and a time counter 15 is started to count a necessary time. While in case that TE>=TH, the time counter 15 is stopped, a capacity of compressor arithmetic part 16 calculates the capacity of a refrigerant compressor 9 corresponding to the counted time, the processed signal is fed into the capacity of compressor controlling part 13, and the driving of the refrigerant compressor 9 is started again.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention (Field of Industrial Application) The present invention controls the compressor capacity according to the cooling load,
This invention relates to a capacity control system for refrigerant compressors that provides a comfortable cooling feeling.

(Prior Art) For example, a refrigerant compressor installed in a vehicle air conditioner generally has a control circuit inserted into the excitation circuit of a magnetic clutch.
A signal from a temperature sensor that detects the temperature at the outlet of the evaporator is input into this control circuit, and the intermittent operation of the magnetic clutch according to the predetermined signal level causes ○N,
It is controlled to be OFF.

However, in this case, torque fluctuations in the driving engine occur when the refrigerant compressor is turned ON and OFF, and the vehicle speed rapidly increases and decreases, causing a large shock to the vehicle.
During N/OFF, the operation is performed at a predetermined fixed capacity, which aggravates the above-mentioned shock, and there is an unreasonable operation that does not match the actual cooling load, making it difficult to obtain the desired cooling feeling and reducing the power consumption. There is a dislike for the lack of effective use of.

To solve this problem, for example, there is a technique disclosed in Japanese Utility Model Application Publication No. 59-79410. In other words, this publication states that when the air conditioner is started, the refrigerant compressor is driven at high capacity to achieve rapid cooling, but when the evaporator outlet temperature reaches close to the set temperature on the high temperature side, the refrigerant compressor is driven from high capacity to low capacity. Switch to the capacity and drive, then maintain the small capacity and set the magnetic clutch to 0N.
- So-called cycling drive, which repeats intermittent operation based on FF operation, is performed, and if the outlet temperature of the evaporator reaches the high-temperature side set temperature or higher, the refrigerant compressor is switched from small capacity to large capacity, and the above-mentioned blower A control device for a refrigerant compressor is shown that allows the outlet temperature to be adjusted within a predetermined set temperature range.

(Problem to be Solved by the Invention) However, in this conventional control device, the capacity of the refrigerant compressor is switched at a high temperature side outside the above set temperature range. Cooling efficiency is poor, and since the refrigerant compressor is operated intermittently in the lower set temperature range, for example, when the above-mentioned cooling load is small, cooling efficiency tends to be excessive, and the actual cooling load There was a problem that sufficient consistency could not be obtained.

The present invention solves these conventional problems and finely controls the capacity of the refrigerant compressor according to the actual cooling load to provide a comfortable cooling feeling. An object of the present invention is to provide a capacity control system for a refrigerant compressor that can confirm proper operation of the compressor and provide smooth and reliable control operations.

(Means for solving the problem) Therefore, the refrigerant compressor capacity control system of the present invention has the following features:
It is characterized by being able to adjust the compressor capacity based on the time required for the air conditioning space to reach a predetermined control temperature, thereby making it possible to obtain a cooling feeling that matches the cooling load of the air conditioning space.

In addition, the capacity control system of the present invention sets the refrigerant compressor to an initial capacity and drives it at the beginning of the cooling operation, and when the refrigerant compressor is driven, the refrigerant compressor increases depending on the time required to reach a predetermined control temperature in the air conditioning space. Primary capacity control to determine proper operation, and after this primary capacity control, the refrigerant compressor is turned on and off within a predetermined control temperature range of the air conditioning space to reach the predetermined control temperature of the air conditioning space. It consists of primary capacity control that allows the amount of compressor S to be adjusted to the above-mentioned initial capacity 1 or less based on the required time, and these primary and secondary capacity controls improve the smoothness of capacity control of the refrigerant compressor. It is characterized by increased reliability.

Furthermore, the capacity control system of the present invention sets the refrigerant compressor to an initial capacity and drives it at the beginning of cooling operation, and when the refrigerant compressor is driven, it determines whether the time required for the air conditioning space to reach a predetermined control temperature is outside the predetermined time. Correct the compressor capacity of the refrigerant compressor that has been improperly set, and restore proper operation of the refrigerant compressor. It is characterized by what it did.

(Example) Hereinafter, an illustrated example in which the present invention is applied to a vehicle air conditioner equipped with a variable capacity refrigerant compressor will be explained. A switching door 4 is provided between the opening 2 and the outside air intake 3 so that it can be opened and closed, and a blower 5 and an evaporator 6 are housed on the downstream side of the switching door 4 in the air blowing direction. A temperature sensor 7 such as a thermistor or a defrost thermoswitch for anti-freezing is attached to the facing surface of the outlet.

The temperature sensor 7 detects the outlet temperature of the evaporator 6 instead of an electric quantity, and sends the detection signal S1 to the control unit 8. The control unit 8 has a built-in microcomputer, for example. The various signals received in the refrigerant compressor 9 are subjected to judgment and calculation processing based on control data stored in advance under conditions, and the processing results are outputted to the variable capacity refrigerant compressor 9 as a control signal S0. .

The control unit 8 is composed of various processing sections, and as shown in FIG. On/off control section 1
1, and a compressor capacity initial setting section 12 that sets the initial capacity of the refrigerant compressor 9 at the beginning of control, that is, at the time of primary capacity control, and this setting section 12 responds to the air conditioning start signal from the air conditioning operation section 10. Based on the control, it operates only at the beginning of the control,
In this embodiment, the initial capacity is set to the maximum capacity, and a signal containing this set capacity is output to the compressor capacity control section 13.

The compressor capacity control unit 13 has a function of directly controlling the amount of refrigerant discharged from the refrigerant compressor 9, and as a control means, for example, a capacity setting that controls a known capacity variable mechanism equipped in the refrigerant compressor 9. In the case of a refrigerant compressor or a swash plate type refrigerant compressor, a regulator is used to control the inclination angle of the swash plate. The control unit 13 initially sets the capacity of the refrigerant compressor 9 to the maximum based on the signal from the setting unit 12, while at the time of secondary capacity control, it determines the actual cooling load based on a compressor capacity calculation unit to be described later. The compressor capacity can be set according to the

The control unit 8 also has the temperature detected by the temperature sensor 7, that is, the outlet temperature TE of the evaporator 6,
A comparison/determination unit 14 is provided to compare and determine the magnitude of the temperature TE with the upper and lower limit temperatures TH, T of a preset control temperature forming a comfortable temperature range, and determines whether TE<T□ and Tε
In the case of ≧T, each determination signal is output to the compressor on/off control section 11 and time counter 15.

That is, if TE<TL, refrigerant compression is 1! At the same time as stopping the driving of I9, the time counter 15 is started to enable measurement of the required time, which will be described later.
If Tε≧TH, the time counter 15 is stopped,
A time counter 15 is used in the compressor capacity calculation section, which will be described later.
Refrigerant pressure according to the measurement time! Calculate the capacity of 119,
The processed signal is sent to the compressor capacity control section 13, and after the capacity adjustment, the refrigerant compressor 9 is restarted.

The time counter 15 starts after canceling and resetting the measurement time of the previous measurement at the same time as the refrigerant compressor 9 is driven or stopped. a gate control circuit that sends a gate control signal with an accurate time width obtained by frequency division from a stable crystal oscillator to a gate circuit; It consists of a counting circuit that counts.

The time counter 15 measures the time t0 required for the outlet temperature TE of the evaporator 6 to reach the lower limit temperature TL or less after the refrigerant compressor 9 is started, and
In the second capacity control process, after the drive of the refrigerant compressor 9 is stopped, the time required for reaching the outlet temperature TE or its upper limit temperature T11 is tl, t2 . . .1. I try to measure it.

Among these, the measurement time t in the primary capacity control. is the time required for the cabin to be cooled down to a predetermined temperature TL or below when the air conditioner starts operating, and that time depends on factors such as inside and outside air temperature, number of passengers, weather, etc. that are involved in forming the cabin temperature. The maximum required time t MAX is set after taking these conditions into consideration, and in the case of 70≦t MAX, the time counter 15 and the refrigerant compressor 9 are stopped, The control operation is shifted to the secondary capacity control process.

On the other hand, if the outlet temperature TE of the evaporator 6 exceeds the set time t MAX but does not become TE < TL,
As shown in the flowchart of the control system in Fig. 3, the process moves to the capacity check process of the refrigerant compressor 9, and if 70 is less than t MAX or the capacity is set below the maximum value, the first We are now moving to the next capacity control.

On the other hand, if to>tMAX and the capacity is less than the maximum value, the time counter 15 is stopped, and the compressor capacity control section 13 is appropriately adjusted, for example, by manual operation.
After increasing the capacity of the refrigerant compressor 9 by a predetermined amount, the process is again transferred to the primary capacity control process to confirm proper operation of the compressor 9.

Also, the time 1. measured in the secondary capacity control process.
．． 12.13...70 is replaced with a signal proportional to the time concerned and input to the compressor capacity calculation section 16, and the time 1. ．． 12...The compressor capacity commensurate with tLl is determined.

That is, the compressor capacity calculation unit 16 stores in advance the measured time by a time counter and the capacity control characteristic value regarding the capacity of the refrigerant compressor 9 as shown in FIG. When a signal is input, the compressor capacity corresponding to the signal level is read out, and a signal having a size corresponding to the capacity is output to the compressor capacity control section 13. In the case of the embodiment, the capacity control characteristics described above are such that the compressor capacity changes linearly with the measurement time of the time counter 15, and the compressor capacity gradually decreases as the measurement time increases.

In this pond, 17 in the figure is the blower motor, 18 is the heater core,
One is a mix door, and 20.21 is a mode switching door.

In the embodiment described above, the capacity control means of the refrigerant compressor 9 in the secondary capacity control process is the time required for the outlet temperature Te of the evaporator 6 to reach its upper limit TH from its lower limit TL, in other words, the refrigerant compression. The time counter 15 measures the time from when the machine 9 stops until it resumes driving.
The measurement result is outputted to the compressor capacity calculation unit 16, but this is not limited to this example, and the time required for the outlet temperature TE to reach TL from T□, that is, in this case, the refrigerant compressor 9 stops after being driven. It is also possible to measure the time required from the time Tε of the temperature Tε to the time TL of the next cycle or to output it to the arithmetic unit 16.
The time required for one cycle from TH time of 1 to TH time of the next cycle, in other words, from OFF to OFF of refrigerant compressor 9
Alternatively, it is also possible to measure the time required from ON to ON and output it in the same manner as above.

In addition, in the above embodiment, in order to obtain a cooling feeling according to the actual cooling load, the capacity of the refrigerant compressor 9 is controlled, or as another means, for example, the outlet temperature TE of the evaporator 6 is controlled. It may be configured to perform variable control according to the cooling load, and furthermore, a temperature sensor 7 may be installed at an appropriate location in the passenger compartment instead of the outlet temperature of the evaporator 6 as a control temperature measurement means for the air conditioning space. , the detection signal S1 of the vehicle interior temperature may be input to the control unit 8.

(Function) The refrigerant compressor capacity control system configured as described above is as follows:
When the vehicle air conditioner is operated, when the air conditioner switch and ONL constituting the air conditioner operating section 1o and the start switch of the refrigerant compressor 9 are turned on, a control operation as shown in FIG. 3 is started.

That is, by operating the air conditioning operating section 10, the operating section 1
When a signal is sent from 0 to the compressor capacity initial setting section 12 and the compressor on/off control section 11, a signal is sent from the setting section 12 to the compressor capacity control section 13,
The variable capacity mechanism constituting the control unit 13 operates to adjust the refrigerant pressure 11 to the initial capacity, that is, the maximum capacity (in the embodiment).
CMAX).

Therefore, the refrigerant compressor 9 is set to the maximum refrigerant discharge amount, and the discharged refrigerant is transferred to the condenser (
(path shown) to the evaporator 6. The refrigerant guided to the evaporator 6 gradually evaporates, and at that time, the air duct 1
It absorbs heat from the air introduced into the interior, cools it, and blows it out from the outlet of the evaporator 6 toward the interior of the vehicle. In this case, as described above, the capacity of the refrigerant compressor 9 is set to the maximum, the amount of refrigerant discharged becomes the maximum amount, and the evaporation action in the evaporator 6 is enhanced, so that rapid cooling of the vehicle compartment becomes possible.

When the outlet temperature TE of the evaporator 6 begins to decrease in this way, the temperature is detected by the temperature sensor 7 installed near the outlet, and the detection signal Sl is sent to the control unit 8 for comparison every moment. - Sent to the determination unit 14. In the comparison/judgment section 14, the detection signal S
1, and the above-mentioned outlet temperature TE corresponding to this signal S1 and the determination reference temperature in the primary capacity control process.
Then, the temperature is compared and determined with respect to the lower limit temperature TL of the TE set in advance.

On the other hand, the time counter 15 starts measuring operation at the same time as the refrigerant compressor 9 is started, and the time t required for the outlet temperature TE of the evaporator 6 to fall below the lower limit temperature TL.

Measure. In this way, the comparison/judgment section 14 and the time counter 15 track the outlet temperature Tε in parallel, and when the temperature Tε gradually decreases and goes below the lower limit temperature 'rL,
The comparison/determination section 14 detects this situation and outputs the determination signal to the time counter 15. The time counter 15 measures the time t when the determination signal is input.

and hold for the time t. The decision will be made as to whether or not it is possible.

In other words, the time measured by the time counter 15 is
If the initially set maximum required time t MAX is less than MAX, the measurement operation is stopped, and the comparison/determination section 14 sends a determination signal to the compressor on/off control section 11 to stop the refrigerant compressor 9 from driving. is stopped, and the primary capacity control process ends. At the same time as this drive is stopped, the time counter 15 is reset, and the measurement operation is restarted to start the second capacity control.

On the other hand, if the measured time t0 by the time counter 15 is greater than or equal to the required time tMAX, the process shifts from the primary capacity control to the capacity check process, and determines whether or not the measured time t0 and the initial capacity of the refrigerant compressor 9 are initially set. 1.
If the initial capacity of the compressor 9 is in a proper state, such as within tMAX or the initial capacity of the compressor 9 is at its maximum value, the process is shifted to the first capacity control process again, and tl.

When the initial capacity of the compressor 9 is less than or equal to the maximum amount while t is greater than or equal to t MAX, the measurement operation of the time counter 15 is stopped;
For example, the compressor capacity is increased by a predetermined amount by manual operation, and the process is again transferred to the first capacity control process.

In other words, in this capacity check process, we check for any troubles such as malfunctions of the control unit 8 or incorrect initial capacity setting of the refrigerant compressor 9, and ensure that there are no problems with the control operation in the next secondary capacity control process. It also has the role of properly setting the capacity of the refrigerant compressor 9 in advance.

Furthermore, it also has the meaning of determining in advance whether or not a predetermined cooling feeling can be obtained by the refrigerant compression 1119 under the actual cooling load that changes depending on the environment inside and outside the vehicle.

In this way, when the outlet temperature Tg of the evaporator 6 becomes lower than the lower limit temperature and the capacity of the refrigerant compressor 9 is properly maintained, and the process moves to the second capacity control process, at the beginning of the transition, as described above. Since the refrigerant compressor 9 has stopped driving and the operation of the air conditioner has been substantially stopped, the outlet temperature Tε of the evaporator 6 remains at the time t measured by the time counter 15, as shown in FIG. After a period of time, in other words, after the drive of the refrigerant compressor 9 has stopped, it begins to rise depending on the environment inside and outside the vehicle interior.

In this case as well, the outlet temperature TI of the evaporator 6 is detected by the temperature sensor 7 installed at the relevant location, and the detection signal S1 is sent to the control unit 8 every moment.
is input to the comparison/judgment section 14. Under these circumstances, when the temperature TE gradually rises and reaches its upper limit temperature TH, this situation is determined by the comparison/judgment section 14, and the determination signal is output to the time counter 15. The time counter 15 stops measuring operation in response to the determination signal,
The measurement time 1. and outputs a signal corresponding to the time t to the compressor capacity calculation section 16.

The compressor capacity calculation unit 16 stores the time measured by the time counter 15, that is, the air outlet temperature TE of the evaporator 6.
The time required for the compressor to reach the upper limit temperature TH from the lower limit temperature TL and the capacity control characteristic value regarding the compressor capacity corresponding to the time are stored in advance, and signals corresponding to the time counters 15 to 7 are input to this. When it is done,
The calculation unit 16 reads the corresponding compressor capacity C1 from the stored information based on the signal level, and outputs a signal corresponding to the capacity C1 to the compressor capacity control unit 13.

Based on the capacity signal level, the compressor capacity control unit 13 operates a capacity setting device that controls a capacity variable mechanism provided in the refrigerant compressor 9, adjusts the capacity of the compressor 9 to the capacity signal level, and adjusts the capacity of the compressor 9 to the capacity signal level. Adjust the operating condition of the compressor 9.

When the drive adjustment of the refrigerant compressor 9 is completed, the signal is input to the compressor 9, and based on the signal and the signal from the compressor on/off control section 11 that has already been input, the capacity adjustment core is adjusted. Refrigerant compressor 9 is started.

When the drive of the refrigerant compressor 9 is restarted in this manner, the discharged refrigerant is guided to the evaporator 6, the outlet temperature TE of the refrigerant is cooled as described above, and the cooling of the passenger compartment is resumed. Therefore, the outlet temperature Tε of the evaporator 6 begins to gradually decrease as shown in FIG. is sent.

The comparison/judgment unit 14 receives the signal S1 and compares the outlet temperature T6, which corresponds to the signal S1, with the determination reference temperature TL, so that the temperature Tε is equal to or lower than the lower limit temperature TL of the outlet. Then, the determination signal is output to the compressor on/off control unit 11 and the time counter 15, and the drive of the refrigerant compression unit 111 is stopped, and at the same time, the time counter 15 is canceled and reset from the previous measurement time t1, and the measurement operation is started. to be restarted.

Therefore, by stopping the drive of the refrigerant compressor 9, the temperature at the outlet of the evaporator 6 rises again according to the environment inside and outside the vehicle interior, and the detection signal S1 from the temperature sensor 7 that detects the temperature T is constantly compared. It is input to the determination section 14. In this way, the outlet temperature TE of the evaporator 6 gradually increases,
When the upper limit temperature T,l is reached, this situation changes from the above comparison.
It is determined by the determination unit 14, the determination signal is sent to the time counter 15, and the counter 15 stops the measurement operation and holds the measurement time t2 (tl<t2),
A signal at a level corresponding to the measurement time t2 is input to the compressor capacity calculation section 16.

The compressor capacity calculation unit 16 takes in the above signal, and based on the signal level at the measurement time t2, reads out the corresponding compressor capacity C2 (Cr>C2) from the compressor capacity control characteristic value stored in the same manner as described above. A signal corresponding to the capacity C2 is output to the compressor capacity control section 13. The compressor capacity control unit 13 adjusts the variable capacity mechanism based on the signal level, adjusts the capacity of the refrigerant compressor 9, and then drives it to resume cooling the vehicle compartment.

That is, in this case, the outlet temperature T of the evaporator 6
The time required to reach the upper limit temperature TH from the lower limit temperature TL of E is somewhat longer than the previous measurement time t1. This means that, after the refrigerant compressor 9 stops driving, for example, there is a change in the environment inside and outside the vehicle that is involved in forming the outlet temperature TE, and this change causes a difference in the required time, that is, the time required for the temperature to rise. I will do it. In other words, the shorter the above-mentioned time required, the faster the temperature rises. Therefore, the vehicle interior, which is an air-conditioning space, is an environment where a large amount of heat flows in or is generated, that is, when the cooling load is high. It means that it is written.

Therefore, when the cooling load is high, a large amount of refrigerant is required to be discharged from the refrigerant compressor 9, so the compressor capacity is set at a high level. Therefore, as in the embodiment, the time measured by the time counter 15 is Ll<
In the case of t2, it means that the cooling load is larger at t1 than at t2, so the compressor capacity in this case is set as C1>C2.

In this way, the capacity of the refrigerant compressor 9 in the secondary capacity control process is finely set according to the actual cooling load, so a cooling feeling that matches the comfort of the passenger compartment can be obtained.
Moreover, the outlet temperature T6 of the evaporator 6 in this case is
Even after adjusting the compressor capacity, the upper and lower limits of temperature T
Since it is substantially stable between H and TL, a uniform cooling feeling can always be obtained.

In addition, the refrigerant compressor 9 is driven at maximum capacity during the primary capacity control at the beginning of control, and is driven at a lower capacity during the secondary capacity control process, so the power required for this drive is saved. In addition to reducing power consumption, the torque fluctuation of the driving engine is reduced, and the refrigerant compressor 9 is turned on and off.
The shock to the vehicle side when FF is activated is reduced,
This results in comfortable driving performance. Despite these various advantages, the configuration is substantially simple and requires no complicated wiring, as the temperature sensor 7 and the control unit 8 are sufficient.
It has the advantage of achieving the intended purpose.

(Effects of the Invention) As described above, the refrigerant compressor capacity control system of the present invention makes it possible to adjust the compressor capacity based on the time required to reach a predetermined control temperature in the air conditioning space. In other words, since the compressor capacity of the refrigerant compressor can be set according to the cooling load of the space that is involved in forming the temperature rise or fall rate of the air conditioning space, a cooling feeling that matches the cooling load can be obtained.
The comfort of the air-conditioned space can be improved, and this effect is particularly suitable for controlling variable capacity refrigerant compressors, which are expected to become popular in recent years.

In addition, in the capacity control system of the present invention, the refrigerant compressor is set to an initial capacity and driven at the beginning of cooling operation, and the refrigerant compressor is adjusted appropriately depending on the time required to reach a predetermined control temperature in the air conditioning space during the drive. The primary capacity control determines the operation, and after this primary capacity control, the refrigerant compressor is operated ON/OFF within a predetermined control temperature range of the air conditioning space to reach the predetermined control temperature of the air conditioning space. It consists of a secondary capacity control that allows the compressor capacity to be adjusted to below the above-mentioned initial capacity based on the time required for Moreover, since the proper operation of the refrigerant compressor can be determined in advance during the primary capacity control process, the smoothness and reliability of the subsequent secondary capacity control can be improved.

Moreover, in the above invention, in the secondary capacity control process in which cooling operation is shifted to steady operation, the compressor capacity is adjusted to below the initial capacity and the refrigerant pressure is 4° to drive the compressor. While the required power can be reduced and power saving can be achieved, fluctuations in the required power during ON-OFF operation can be suppressed. This has the effect of reducing torque fluctuations in the driving engine during driving, reducing shock to the vehicle and providing comfortable driving performance.

Further, in the capacity control system of the present invention, the refrigerant compressor is set to the initial capacity and driven at the beginning of the cooling operation, and when the refrigerant compressor is driven, the time required to reach the predetermined control temperature in the air conditioning space is outside the predetermined time. By correcting the compressor capacity of an incorrect refrigerant compressor and restoring proper operation of the refrigerant compressor, for example, a refrigerant compressor due to an incorrect initial capacity setting can be properly repaired to encourage its use and be used as intended. This has the effect of being applicable to control systems.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a schematic diagram showing one embodiment of the present invention, Fig. 2 is a block diagram showing main parts of the configuration of a control system applied to the present invention, and Fig. 3 is a schematic diagram showing an embodiment of the present invention. FIG. 4 is a flowchart showing an example of a control system, FIG. 4 is a cooling characteristic diagram showing changes in evaporator outlet temperature when the present invention is used, and FIG. 5 is a characteristic diagram showing an example of compressor capacity control characteristics. 9... Refrigerant compressor 9] Pond Fig. 1 □

Claims (3)

[Claims] (1) A refrigerant compressor capacity control system, characterized in that the compressor capacity can be adjusted based on the time required to reach a predetermined control temperature in an air conditioning space. (2) The first stage, in which the refrigerant compressor is set to the initial capacity and driven at the beginning of cooling operation, and the proper operation of the refrigerant compressor is determined based on the time required to reach a predetermined control temperature in the air conditioning space during the drive. After the first capacity control, the refrigerant compressor is turned on and off within a predetermined control temperature range of the air conditioning space, and the compressor capacity is adjusted based on the time required to reach the predetermined control temperature of the air conditioning space. A capacity control system for a refrigerant compressor comprising secondary capacity control that allows the amount of refrigerant to be adjusted to below the above-mentioned initial capacity. (3) Inappropriate refrigerant compressor in which the refrigerant compressor is set to the initial capacity and driven at the beginning of cooling operation, and the time required to reach the predetermined control temperature in the air conditioning space during said drive is outside the predetermined time. A capacity control system for a refrigerant compressor, characterized in that the compressor capacity of the refrigerant compressor is corrected to restore proper operation of the refrigerant compressor.