JPH08296907A - Controller for compressor in air conditioning system - Google Patents

Abstract

PURPOSE: To provide a controller for a compressor in an air conditioning system which can restrict an excessive change in torque of a power source without passing through a so-called half-clutch position during the connection control of a clutch mechanism. CONSTITUTION: A controller 16 reads an evaporator temperature TH, a high pressure side refrigerant pressure and a low pressure side refrigerant pressure respectively based on input signals from sensors 13-15. Based on the evaporator temperature, the high pressure side refrigerant pressure and the low pressure side refrigerant pressure read, the controller 16 judges whether an electromagnetic clutch 4 in a separation state should be subjected to a connection control or no. At this point, when at least one of the high pressure side refrigerant pressure and the low pressure side refrigerant pressure is not below an individual set value, the connection of the electromagnetic clutch 4 is not made even if the evaporator temperature indicates a value demanding the operation of a compressor 2 (above a specified temperature). The high pressure side or the low pressure side refrigerant pressure below the set value reflects the condition of an external refrigerant circuit 5 that allows the minimizing of a compression load at the start of the compressor 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioning system mounted on a vehicle, for example, and more particularly to a compressor control device in the system.

[0002]

2. Description of the Related Art In an air conditioning system mounted on a vehicle, a compressor is drivingly connected to an engine of the vehicle via an electromagnetic clutch. In the system, the compressor is repeatedly operated and stopped intermittently by connecting and disconnecting the electromagnetic clutch according to the cooling load.

Particularly, when the electromagnetic clutch is connected,
As shown in FIG. 6A, the core of the electromagnetic clutch is excited by the maximum drive current at the same time as the clutch connection command. Therefore, as shown in FIG. 6B, in addition to the compression load of the compressor, the moment of inertia of the rotating portion is instantaneously applied to the engine as compressor torque, resulting in excessive torque fluctuation of the engine. As a result, a deceleration shock occurs in the vehicle, causing problems such as deterioration of drivability.

As a method for solving such a problem, it is possible to apply the technique disclosed in Japanese Patent Laid-Open No. 63-45481. In this technique, FIG.
As shown in FIG. 5, the duty ratio is controlled such that the drive current for exciting the core of the electromagnetic clutch is the maximum drive current and the required suction current for connecting the electromagnetic clutch to the extent that the electromagnetic clutch is not disengaged. Therefore, when the electromagnetic clutch is connected, the duty ratio of this drive current is gradually biased from the required suction current value side to the maximum drive current value side, so that the armature and engine from the input shaft of the compressor The attraction force with the rotor on the driving force input side is gradually increased. as a result,
As shown in FIG. 7B, the compressor torque at the time of starting the compressor can be gradually increased, excessive torque fluctuation of the engine is prevented, and deceleration shock is reduced.

[0005]

However, in the above-mentioned prior art publication, when the duty ratio of the drive current is low, the electromagnetic clutch is in a half-clutch state and slippage occurs between the rotor and the armature. Therefore, the following problems have occurred.

The portions of the rotor and the armature that slide with each other are worn, leading to a reduction in the durability of the electromagnetic clutch. The wear of the sliding part between the rotor and armature reduces the friction coefficient of that part, which makes it impossible to achieve a smooth connection in the initial state (before wear), and the core is excited by the maximum drive current. Even in this case, slippage occurs between the rotor and the armature, and the transmission loss of the driving force from the engine increases.

Due to the resistance heat generated in the sliding portion, not only the electromagnetic clutch but also the rubber member (for example, a seal member) of the compressor disposed in the vicinity thereof is deteriorated. Abnormal noise occurs due to slippage in the sliding part.

The present invention has been made by paying attention to the problems existing in the above-mentioned prior art, and the object thereof is to control the connection of the clutch mechanism without using a so-called half-clutch state. Another object of the present invention is to provide a control device for a compressor in an air conditioning system, which can suppress excessive torque fluctuations.

[0009]

In order to achieve the above object, in the invention of claim 1, a state detecting means for detecting the state of the evaporator, a detection value by the state detecting means and a preset value are provided. First comparing means for comparing, pressure detecting means for detecting the refrigerant pressure in the external refrigerant circuit, second comparing means for comparing a value detected by the pressure detecting means with a preset value, and Dissociation is possible only when the detection value detected by the state detection means is determined by the first comparison means to be greater than or equal to the set value and the detection value by the pressure detection means is determined to be less than or equal to the set value in the second comparison means. It is a control device for a compressor provided with a clutch control means for performing connection control with respect to the clutch mechanism in a state.

According to another aspect of the invention, the pressure detecting means is a high pressure side pressure detecting means for detecting a high pressure side refrigerant pressure in the external refrigerant circuit or a low pressure side pressure detecting means for detecting a low pressure side refrigerant pressure. Have at least one.

In the invention of claim 3, the pressure detecting means is composed of a high pressure side pressure detecting means and a low pressure side pressure detecting means, and the second comparing means is detected by the high pressure side pressure detecting means. It is compared whether or not at least one of the detected value and the detected value detected by the low pressure side pressure detecting means is less than or equal to the set value set for each.

In the invention of claim 4, the high pressure side pressure detecting means is disposed in the external refrigerant circuit near the discharge side of the compressor. In the invention of claim 5, the low pressure side pressure detecting means is arranged in the vicinity of the suction side of the compressor in the external refrigerant circuit.

In the invention of claim 6, the pressure detecting means also serves as the second comparing means, and a signal is sent to the clutch control means only when the pressure above the set value is detected or when the pressure below the set value is detected. Is output.

[0014]

In the invention of claim 1 having the above-mentioned structure, the state of the evaporator is detected by the state detecting means. The first comparison means compares the detection value detected by the same state detection means with a preset value. The pressure detection means detects the refrigerant pressure in the external refrigerant circuit. The second comparison means compares the value detected by the pressure detection means with a preset value. The clutch control means determines that the detection value detected by the state detection means in the first comparison means is equal to or larger than the set value, and the detection value detected by the pressure detection means in the second comparison means is the set value. Only when it is determined that the clutch mechanism is in the disengaged state, the connection control is performed.

When the refrigerant pressure detected by the pressure detecting means is higher than the set value, the compression load at the time of starting the compressor becomes large. That is, if the clutch mechanism is connected under the condition of the external refrigerant circuit, the increase of the compressor torque becomes excessive.

However, in the present invention, since the clutch mechanism is prevented from being connected when the refrigerant pressure in the external refrigerant circuit is higher than the set value, it is possible to reliably suppress an excessive increase when the clutch mechanism is connected. You can

In the invention of claim 2, the pressure detecting means is
It is composed of at least one of the high-pressure side pressure detecting means and the low-pressure side pressure detecting means. By the way, when the pressure of the refrigerant on the high pressure side is high in the external refrigerant circuit, the compressor must discharge the refrigerant gas against the high pressure at the time of starting, and the compression load becomes large. Therefore, the high pressure side pressure detecting means detects the high pressure side refrigerant pressure in the external refrigerant circuit. Then, avoid connecting the clutch mechanism in the situation where the high-pressure side refrigerant pressure is higher than the set value.

Further, when the low-pressure side refrigerant pressure detected by the low-pressure side pressure detecting means is higher than the set value, the compressor sucks the higher-pressure refrigerant gas at the time of starting, and the higher pressure The compression load must be performed against the refrigerant pressure, which increases the compression load. Therefore, the low pressure side pressure detecting means detects the low pressure side refrigerant pressure in the external refrigerant circuit. Then, avoid connecting the clutch mechanism when the low-pressure side refrigerant pressure is higher than the set value.

As described above, by providing at least one of the high-pressure side and low-pressure side pressure detecting means, it is possible to grasp a suitable condition of the external refrigerant circuit in which the compression load is reduced when the compressor is started, Since the clutch mechanism connection control is performed based on this, it is possible to reliably suppress an excessive increase in the compressor torque at the time of starting the compressor.

In the invention of claim 3, the pressure detecting means is
It is composed of high pressure side and low pressure side pressure detecting means.
Then, the second comparing means determines whether at least one of the detection value detected by the high pressure side pressure detecting means and the detection value detected by the low pressure side pressure detecting means is less than or equal to the set value set for each. Compare. Therefore, the clutch control means does not allow the clutch mechanism to be connected unless at least one of the high-pressure side refrigerant pressure and the low-pressure side refrigerant pressure is equal to or less than the set value.

In this way, by detecting both the high pressure side and low pressure side refrigerant pressures, the condition of the external refrigerant circuit suitable for connecting the clutch mechanism can be finely determined.
In other words, if only one of the pressure detecting means is used, for example, even if the detected value detected by the other pressure detecting means is a value indicating the state of the external refrigerant circuit suitable for connecting the clutch mechanism, it is recognized. Cannot be done, and the opportunity to connect a suitable clutch mechanism will be missed. However, in the present invention, by providing both pressure detecting means, the chances of connecting the clutch mechanism increase, and when the value detected by the state detecting means is an operation request to the compressor, the clutch mechanism is connected to the request. The delay can be reduced.

According to the fourth aspect of the invention, since the high pressure side pressure detecting means is arranged near the discharge side of the compressor in the external refrigerant circuit, it is directly related to the magnitude of the compression load at the time of starting the compressor. It is possible to accurately detect the high pressure side refrigerant pressure in the vicinity of the discharge side, which affects the.

According to the fifth aspect of the invention, since the low pressure side pressure detecting means is arranged near the suction side of the compressor in the external refrigerant circuit, it is directly related to the magnitude of the compression load when the compressor is started. It is possible to accurately detect the low-pressure side refrigerant pressure in the vicinity of the suction side that affects the.

In the invention of claim 6, the pressure detecting means also serves as the second comparing means, and only when the pressure above the set value is detected or when the pressure below the set value is detected, the clutch control means is provided. Output a signal to. By doing so, the device configuration can be simplified.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment embodying the present invention will be described below. FIG. 1 is a schematic diagram showing a refrigerant circuit configuration and its peripheral configuration of an air conditioning system of the present embodiment mounted on a vehicle, in which FIG. 1 shows an engine of the vehicle. The compressor 2 is drivingly connected to the engine 1 via a transmission system 3 including a belt 3α and the like, and an electromagnetic clutch 4 is interposed between the compressor 2 and the transmission system 3. The external refrigerant circuit 5 is connected between the discharge side 2α and the suction side 2β of the compressor 2, and a condenser 6, an expansion valve 7 and an evaporator 8 are arranged on the external refrigerant circuit 5.

As shown in FIG. 3, the electromagnetic clutch 4 is
When the engine 1 is rotated, the rotor 10 is driven to rotate via the belt 3α, the armature 11 connected to the input shaft 2γ of the compressor 2 via the plate spring 9 so as to be able to rotate integrally, and the drive current are supplied. It has a core 12 that is excited. When the core 12 is excited by the drive current, the armature 11 is attracted to the rotor 10 side against the spring force of the leaf spring 9, and the both 10 and 11 are pressed against each other. Therefore, the driving force of the engine 1 transmitted to the rotor 10 via the belt 3α is transmitted to the input shaft 2γ via the armature 11 to drive the compressor 2. When the core 12 is demagnetized, the armature 11 is separated from the rotor 10 by the spring force of the leaf spring 9, and the transmission of the driving force from the engine 1 is interrupted.

When the compressor 2 is operated by connecting the electromagnetic clutch 4, the high pressure refrigerant gas discharged by the compression action of the compressor 2 is supplied to the condenser 6. The refrigerant gas supplied to the condenser 6 is condensed into a liquid refrigerant,
It is supplied to the expansion valve 7. The liquid refrigerant is adiabatically expanded in the expansion valve 7 and supplied to the evaporator 8. Then, heat is exchanged in the evaporator 8 to cool the air flowing into the vehicle. After this, the refrigerant gas again flows into the compressor 2 and is compressed.

Next, the control system of the air conditioning system will be described. As shown in FIG. 1, the temperature sensor 13 as the state detecting means is arranged in the evaporator 8 and outputs a signal corresponding to the temperature TH on the outlet side of the evaporator 8 (hereinafter referred to as the evaporator temperature) TH. Further, the high pressure side pressure sensor 14 as the high pressure side pressure detecting means is provided on the external refrigerant circuit 5 in the compressor 2
Of the refrigerant gas disposed in the vicinity of the discharge side 2α and having a relatively high pressure in the same circuit 5 (hereinafter, referred to as the pressure of the refrigerant gas near the discharge side 2α).
The pressure corresponding to the high pressure side refrigerant pressure) Pd is output.
Further, the low pressure side pressure sensor 15 as the low pressure side pressure detecting means is disposed in the vicinity of the suction side 2β of the compressor 2, and the circuit 5
A signal corresponding to the pressure (hereinafter, referred to as the low pressure side refrigerant pressure) Ps of the refrigerant gas in the vicinity of the suction side 2β indicating a relatively low pressure is output.

As shown in FIGS. 1 and 2, the control device 16 constituting the first and second comparison means and the clutch control means in this embodiment is a central processing unit (CPU) 1.
7, a read-only memory (ROM) 18 for storing control programs and the like, a readable / writable memory (RAM) 19 for temporarily storing various information, and the like. Each of the sensors 13 to 15 is C through the external input circuit 20.
It is connected to the PU 17. Also, the electromagnetic clutch 4
The (core 12) is connected to the CPU 17 via the external output circuit 21.
It is connected to the.

Then, the CPU 17 controls the sensors 13-1 to 13-1.
On the basis of the signal input from 5, the excitation / demagnetization of the core 12, that is, the connection / disconnection control of the electromagnetic clutch 4 is performed.
Next, the operation of the control device 16 will be described with reference to the flowchart of FIG.

When the control program is started, the CPU 17 determines in step 101 whether the electromagnetic clutch 4 is in the engaged state or the disengaged state. If it is determined in step 101 that the electromagnetic clutch 4 is in the engaged state, the process proceeds to step 102. In step 102, the evaporator temperature TH is read based on the input signal from the temperature sensor 13. Then, the process proceeds to step 103, and it is determined whether the read evaporator temperature TH is lower than the set temperature α. It should be noted that the temperature lower than the set temperature α reflects a situation in which frost (with frost: leading to a decrease in cooling capacity) is likely to occur in the evaporator 8.

When it is determined in step 103 that the evaporator temperature TH is not lower than the set temperature α, the electromagnetic clutch 4 in the connected state is not disengaged, that is, the operation of the compressor 2 is continued and this routine is executed. It ends once.

When it is judged in step 103 that the evaporator temperature TH is lower than the set temperature α, it is judged that the compressor 2 continues to operate, and frost is generated in the evaporator 8, and the process proceeds to step 104. . Therefore, in the same step 104, control is performed to demagnetize the core 12 to disengage the electromagnetic clutch 4 in the connected state and stop the operation of the compressor 2.

When it is determined in step 101 that the electromagnetic clutch 4 is in the disengaged state, the process proceeds to step 105. In step 105, the evaporator temperature TH is read based on the input signal from the temperature sensor 13. Next, step 1 as the first comparison means
At 06, it is determined whether the read evaporator temperature TH is equal to or higher than the set temperature α.

If the evaporator temperature TH is not equal to or higher than the set temperature α in step 106, it is determined that the start-up of the compressor 2 in this situation causes frost in the evaporator 8, and the connection control of the electromagnetic clutch 4 is performed. Instead, the routine is once terminated and the disengaged state of the electromagnetic clutch 4 is continued.

If it is determined in step 106 that the evaporator temperature TH is equal to or higher than the set temperature α, the process proceeds to step 107. In step 107,
The high-pressure side and low-pressure side refrigerant pressures Pd and Ps are read based on the input signals from the high-pressure side and low-pressure side pressure sensors 14 and 15, respectively. Next, the process proceeds to step 108 as the second comparing means, and the read high pressure side and low pressure side refrigerant pressures Pd, Ps are the high pressure side and low pressure side refrigerant pressures P shown in FIG.
It is referred to as a preset map having d and Ps as parameters, and this reference result is obtained in the next step 109.
It is determined whether or not the connection of the electromagnetic clutch 4 is permitted.

The map will be described below.
At least one of the high-pressure side and low-pressure side refrigerant pressures Pd, Ps is set to be a set value β or γ or less (hatched) as an area where the electromagnetic clutch 4 is allowed to be connected, and the other areas are set. The region, that is, the region where neither the high-pressure side refrigerant pressure Pd nor the low-pressure side refrigerant pressure Ps, Ps is equal to or less than the set values β and γ (no hatching) is the region where the connection of the electromagnetic clutch 4 is prohibited.

That is, when the electromagnetic clutch 4 is connected in the state of the external refrigerant circuit 5 in which the high-pressure side refrigerant pressure Pd exceeds the set value β, the compressor 2 resists the high pressure at the time of starting and the refrigerant gas is discharged. Since it has to be discharged, the compression load increases. In other words, if the electromagnetic clutch 4 is connected in a situation where the high-pressure side refrigerant pressure Pd shows a value equal to or lower than the set value β, the compression load of the compressor 2 at the time of start-up becomes small.

Further, the reason why the low pressure side refrigerant pressure Ps is also detected at the same time is that the low pressure side refrigerant pressure Ps also affects the magnitude of the compression load of the compressor 2 at the time of starting.
That is, when the refrigerant gas having a higher pressure is sucked at the time of starting the compressor 2, the compression load of the compressor 2 that compresses the refrigerant gas increases. Therefore, by detecting the low-pressure side refrigerant pressure Ps and connecting the electromagnetic clutch 4 in the situation where the same detection value Ps becomes equal to or less than the set value γ, the compressor 2 of the compressor 2 at the time of startup is similar to the above. The compression load is small.

However, if it is determined in step 109 that the electromagnetic clutch 4 is in the suitable state, the process proceeds to step 110, and the core 12 of the electromagnetic clutch 4 is excited by the maximum drive current. Therefore, the electromagnetic clutch 4 is connected without the half-clutch state,
The driving force of the engine 1 is transmitted to the compressor 2.

When it is judged in the same step 109 that the situation is not suitable for connecting the electromagnetic clutch 4, the routine jumps to step 107 (the electromagnetic clutch 4 is in a disengaged state, so that the evaporator temperature is (TH hardly changes) Until the condition becomes suitable for the clutch connection, that is, until at least one of the high-pressure side and low-pressure side refrigerant pressures Pd, Ps is reduced to the set value β or γ or less, steps 107 to 109 are performed. It waits by being repeated.

As described above, in the present embodiment having the above-described structure, the refrigerant pressures Pd, Ps which influence the magnitude of the compression load at the time of starting the compressor 2 are checked, and the refrigerant pressures Pd, Ps are checked.
Only in a suitable situation where is less than or equal to the set values β and γ, the connection of the electromagnetic clutch 4 in the disengaged state is allowed. Therefore, the following effects can be achieved.

As shown in FIG. 6 (b), the evaporator temperature TH
When the value exceeds the set value α, it is possible to ensure an excessive increase in the compressor torque applied to the engine 1 when the compressor 2 is started, as compared with the former related art in which the electromagnetic clutch 4 is uniquely connected. Can be suppressed to As a result, excessive torque fluctuations transmitted to the engine 1 can be reduced, and deceleration shocks that occur in the vehicle can be suppressed.

At the time of controlling the connection of the electromagnetic clutch 4, as shown in FIG. 6 (a), the core 12 is excited by directly energizing the maximum drive current. Is not involved. Therefore, it is possible to prevent the durability of the electromagnetic clutch 4 from being deteriorated due to wear caused by the slip between the rotor 10 and the armature 11. Also,
It is possible to suppress deterioration of each member constituting the electromagnetic clutch 4 and the compressor 2 due to resistance heat of a sliding portion between the rotor 10 and the armature 11. Further, no abnormal noise is generated from the sliding portions of the both 10 and 11.

Refrigerant pressure P at two places, high pressure side and low pressure side
By detecting d and Ps, it is possible to finely recognize the situation (which can suppress deceleration shock) suitable for connecting the electromagnetic clutch 4. Therefore, it is possible to suppress the response delay of the present device with respect to the operation request of the compressor 2 detected by the temperature sensor 13, and it is possible to perform an appropriate cooling operation. For example, if only the high-pressure side refrigerant pressure Pd is judged, the area surrounded by the two-dot chain line shown in FIG. 4 is the area where the electromagnetic clutch 4 is prohibited from being connected, and the low-pressure side refrigerant pressure Ps is assumed.
Even if is a pressure in a region where the deceleration shock can be reduced (set value γ or less), the control device 16 cannot recognize it. Therefore, the opportunity of suitable clutch connection is missed (the waiting time becomes long due to the repetition of steps 107 to 109).

The high pressure side pressure sensor 14 is arranged near the discharge side 2α of the compressor 2, and the low pressure side pressure sensor 15 is arranged near the suction side 2β. That is, it is possible to accurately detect the refrigerant pressures Pd and Ps that directly affect the magnitude of the compression load when the compressor 2 is started, and it is preferable to determine the connection of the electromagnetic clutch 4 based on the refrigerant pressures Pd and Ps.

The following embodiments can be carried out without departing from the spirit of the present invention. (1) In order to embody the invention of claim 6, the pressure sensors 14 and 15 are changed to pressure sensitive devices using diaphragms, and when the pressures are below set values β and γ, respectively, the contact points of the diaphragm and a predetermined interval therebetween. It is configured so that the contact which is faced with is contacted and the signal is output to the OR circuit. That is, the pressure sensitive device constitutes the pressure detecting means and the second comparing means. Then, a signal is output to the AND circuit according to the OR condition of the output signal from the high pressure side pressure sensitive device and the output signal from the low pressure side pressure sensitive device.

The temperature sensor 13 is connected to the comparator, and only when the signal corresponding to the temperature equal to or higher than the set temperature is input to the comparator as the first comparing means.
Outputs a signal to the AND circuit.

Under the AND condition of the signal from the comparator and the signal from the OR circuit, for example, the relay switch interposed between the power source and the electromagnetic clutch 4 is turned on. By doing this, the CPU 1
7, the ROM 18, the RAM 19 and the like are unnecessary, and the configuration can be simplified. (2) The pressure sensitive device in (1) above is changed to one that outputs a signal at a pressure exceeding the set values β and γ, and the OR circuit is changed to a NAND circuit. Then, depending on the NAND condition of the output signals from the high-pressure side pressure-sensitive device and the low-pressure side pressure-sensitive device,
To be configured to output a signal to the D circuit. (3) In the above embodiment, the state detecting means is the temperature sensor 13 that detects the temperature on the outlet side of the evaporator 8. This may be changed and embodied in other means capable of grasping the atmosphere in which frost is likely to occur in the evaporator 8, such as a flow rate sensor that detects the flow rate of the refrigerant on the outlet side of the evaporator 8. (4) In the above-described embodiment, the electromagnetic clutch 4 is adapted to be engaged when the drive current is applied, but when the drive current is applied, the connection state between the rotor 10 and the armature 11 is changed. It may be dissociated. (5) High pressure side pressure sensor 14 or low pressure side pressure sensor 1
Consist of only 5.

[0050]

According to the inventions of claims 1 and 2 having the above-mentioned structure, it is possible to reliably suppress an excessive torque fluctuation of the power source when the clutch mechanism is engaged. The deceleration shock that occurs at startup can be reduced.

According to the third aspect of the present invention, by detecting both the high pressure side and the low pressure side refrigerant pressure, the circuit condition suitable for connecting the clutch mechanism can be finely recognized.
It is possible to suppress the connection delay of the clutch mechanism with respect to the operation request to the compressor.

According to the inventions of claims 4 and 5, the situation of the external refrigerant circuit can be accurately recognized. According to the invention of claim 6, the device configuration can be simplified.

[Brief description of drawings]

FIG. 1 is a schematic view of an air conditioning system, showing a refrigerant circuit and its peripheral configuration.

FIG. 2 is a block diagram showing an electrical configuration of a control device.

FIG. 3 is a vertical sectional view of an electromagnetic clutch.

FIG. 4 is a graph showing a control map.

FIG. 5 is a flowchart showing the operation of the control device.

FIG. 6 is a diagram showing the former conventional technique, (a) is a graph showing a drive current value for exciting the core, and (b) is a compressor torque at the time of starting the compressors of the conventional technique and this embodiment. A graph comparing the changes in.

7A and 7B are diagrams showing a latter conventional technique, in which FIG. 7A is a graph showing a drive current value for exciting a core, and FIG. 7B is a graph showing a change in compressor torque at the time of starting the compressor.

[Explanation of symbols]

1 ... Engine as power source, 2 ... Compressor, 4 ... Electromagnetic clutch as clutch mechanism, 5 ... External refrigerant circuit, 8 ...
Evaporator, 13 ... Temperature sensor as state detecting means, 14
... High pressure side pressure sensor as high pressure side pressure detecting means, 15
... Low pressure side pressure sensor as low pressure side pressure detecting means, 16
... A control device as first comparison means, second comparison means, and clutch control means.

Front Page Continuation (72) Inventor Akira Nakamoto 2-1-1 Toyota-cho, Kariya city, Aichi Stock company Toyota Industries Corp.

Claims (6)

[Claims] 1. An air conditioning system comprising a compressor drivingly connected to a power source via a clutch mechanism and an external refrigerant circuit including an evaporator connecting a discharge side and a suction side of the compressor, State detecting means for detecting the state of the container, first comparing means for comparing a value detected by the state detecting means with a preset value, and pressure detecting means for detecting the refrigerant pressure in the external refrigerant circuit. Second comparing means for comparing the value detected by the pressure detecting means with a preset value, and the detected value detected by the state detecting means is judged to be greater than or equal to the set value by the first comparing means, and Of a compressor provided with clutch control means for performing connection control for the clutch mechanism in the disengaged state, only when the value detected by the pressure detection means is less than or equal to the set value by the second comparison means. Control device. 2. The pressure detecting means comprises at least one of a high pressure side pressure detecting means for detecting a high pressure side refrigerant pressure in an external refrigerant circuit and a low pressure side pressure detecting means for detecting a low pressure side refrigerant pressure. A control device for a compressor according to Item 1. 3. The pressure detecting means is composed of a high pressure side pressure detecting means and a low pressure side pressure detecting means, and the second comparing means is a detection value detected by the high pressure side pressure detecting means or a low pressure side. The control device for a compressor according to claim 2, wherein at least one of the detection values detected by the pressure detection means is compared with each other to determine whether or not the detection value is equal to or less than a set value set for each. 4. The high pressure side pressure detecting means is arranged in the vicinity of the discharge side of the compressor in the external refrigerant circuit.
Alternatively, the control device for the compressor according to Item 3. 5. The low pressure side pressure detecting means is arranged in the vicinity of the suction side of the compressor in the external refrigerant circuit.
Alternatively, the control device for the compressor according to Item 3. 6. The pressure detecting means also serves as a second comparing means, and outputs a signal to the clutch control means only when a pressure above a set value is detected or when a pressure below a set value is detected. The control device of the compressor in any one of 1-5.