JPH06206441A - Compressor operation monitoring device of refrigerating cycle - Google Patents

Abstract

PURPOSE:To monitor the operating condition of a compressor to a driving source without relying on a rotation sensor, by utilizing effectively the fact that an abnormal condition of the compressor has a close relation with the variation of the pressure of its discharge coolant, when the abnormal condition of the compressor such as a lock is monitored. CONSTITUTION:When the abnormal condition of a compressor 60 such as a lock is monitored, a coolant pressure sensor 150a to detect the discharge coolant pressure in a piping P2 is adopted, the pulsation cycle of the discharge coolant pressure is operated by the coolant pressure sensor 150a, a slippage corresponding to the difference of the rotation frequencies of the compressor 60 and an engine E is operated from the operated pulsation cycle, and depending on the result of operation, it is monitored whether there is an abnormal condition such as a lock in the compressor 60 or net.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating cycle for a vehicle air conditioner, a refrigerating device, a general building air conditioner, a refrigerating device, a refrigerating device, etc. The present invention relates to an operating condition monitoring device suitable for monitoring the operating condition of a vehicle.

[0002]

2. Description of the Related Art Conventionally, for example, in an air conditioner for an automobile, first detecting means for detecting an engine speed as an engine speed, as disclosed in JP-A-58-71214. And second detecting means for detecting the rotation speed of the compressor driven by the engine under the engagement of the electromagnetic clutch as the compressor rotation speed, (the detected compressor rotation speed / the engine rotation speed). Monitor whether the speed ratio of (speed) has a predetermined ratio relationship,
There is a device in which an output signal is generated when a state that is not in a predetermined ratio relationship exceeds a predetermined time, and the electromagnetic clutch is disengaged to stop the compressor when it is determined that the compressor has an abnormality.

[0003]

However, in such a configuration, since rotation sensors such as electromagnetic pickups are usually adopted as the first and second detecting means, these rotation sensors are not adopted. There was a problem that the cost increased.

Therefore, in order to cope with such a situation, the present invention provides a compressor operation monitoring device for a refrigeration cycle,
When monitoring anomalies such as compressor lock, it is possible to effectively utilize the fact that the presence / absence of a compressor is closely related to the change in the discharge refrigerant pressure, without depending on the rotation sensor as described above. It is intended to monitor the operating condition of the compressor drive source.

Further, according to the present invention, in a compressor operation monitoring device for a refrigeration cycle, the operation state of a compressor drive source is monitored without depending on the rotation sensor as described above, and the result of the monitoring is the The compressor is to be stopped when an abnormality such as a lock is displayed.

[0006]

In order to solve the above problems, the present invention provides a compressor for transmitting power from a drive source to compress and discharge a refrigerant, and power transmission from the drive source to the compressor. A refrigeration cycle that has a power transmission means that operates according to the operation, and that circulates the compressed refrigerant discharged from this compressor, a refrigerant pressure detection means that detects the pressure of the compressed refrigerant discharged from the compressor, and the refrigerant pressure And an operating state monitoring means for monitoring the operating state of the compressor with respect to the drive source based on the refrigerant pressure detected by the detecting means.

[0007]

In the present invention thus constructed, in monitoring the operating state of the compressor, the presence or absence of an abnormal operation of the compressor is closely related to the change in the discharge refrigerant pressure. By effectively utilizing that, the pressure of the compressed refrigerant discharged from the compressor is detected by the refrigerant pressure detecting means, and the operating state of the compressor with respect to the drive source is determined based on the refrigerant pressure detected by the refrigerant pressure detecting means. The operation state monitoring means monitors. Therefore, conventionally, by adopting the existing refrigerant pressure detecting means that is provided for detecting an abnormally high pressure or an abnormally low pressure of the refrigeration cycle, without using a separate rotation sensor such as an electromagnetic pickup. It is possible to properly monitor the operating state of the compressor while preventing cost increase.

Further, in the present invention, there is provided stop means for stopping the operation of the power transmission means when the monitoring result of the operation state monitoring means reaches a predetermined abnormal operation state of the compressor, and the power transmission means. When the operation is stopped, the power transmission to the compressor is cut off,
While achieving the above-mentioned effects, the compressor can be properly stopped at the time of an abnormality such as the lock of the compressor.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an example in which the present invention is applied to a vehicle air conditioner. The air conditioner includes an air duct 10
The air duct 10 is provided with a blower 2
0, the evaporator 30, the air mix damper 40, and the heater core 50 are sequentially arranged from the air flow inlet side of the air duct 10 to the air outlet side. Blower 20
Is driven by the blower motor 21 to drive the air duct 10
An air flow is introduced into the interior from the air flow introduction port side, and the evaporator 30, the air mix damper 40, and the heater core 50 are introduced.
The air is blown out as a blown air flow into the passenger compartment of the vehicle through. The evaporator 30 is a cooling element of the refrigeration cycle R, and cools the blown air flow from the blower 20 according to the inflow refrigerant. The air mix damper 40 is driven by a servo motor 41, and according to its opening degree,
The ratio of the inflow amount of the cooling air flow from the evaporator 30 to the heater core 50 and the bypass amount of the cooling air flow from the evaporator 30 to the heater core 50 is adjusted. The heater core 50 is a heat exchanger that heats the inflowing cooling air flow by using the cooling water of the engine E as a heat source.

The refrigeration cycle R has a compressor 60. The compressor 60 is rotated by the power transmitted from the engine E of the vehicle via the pulley mechanism 70 and the electromagnetic clutch 80, and the compressor 60 from the evaporator 30 is rotated. Outflow refrigerant pipe P1
Through the pipe P2 and discharged to the condenser 90. The pulley mechanism 70 includes a pulley 71 coaxially supported by the output shaft of the engine E, a pulley 72 coaxially mounted on the outer peripheral surface of the electromagnetic clutch 80, and a belt 73 wound around these pulleys 71, 72. It is composed by. Thus, the pulley mechanism 70 transmits the power from the engine E to the electromagnetic clutch 80 via the pulley 71, the belt 73 and the pulley 72. In this embodiment, the pulley mechanism 70 and the electromagnetic clutch 80 constitute a power transmission means.

The electromagnetic clutch 80 is coaxially supported by the rotary shaft of the compressor 60. The engagement of the electromagnetic clutch 80 transmits the power from the pulley 72 to the compressor 60, and the electromagnetic clutch 80 also transmits the power. Due to the dissociation, the pulley 6 is removed from the compressor 6
It is well known to cut off the transmission of power to zero. The condenser 90 is a heat exchanger that condenses the inflowing compressed refrigerant.
The receiver 100 connects the condensed refrigerant from the condenser 90 to the pipe P.
The liquid layer component and the gas layer component are separated through 3 and the liquid layer component is caused to flow into the expansion valve 110 through the pipe P4 as a circulating refrigerant. The expansion valve 110 causes the inflowing refrigerant to expand and flow into the evaporator 30 through the pipe P5.

Electric control device 120 (hereinafter, ECU 120
Means a desired set temperature in the passenger compartment set by the temperature setter 130, and an actual temperature of the passenger compartment detected by the sensor group 140 (hereinafter, referred to as inside temperature),
The temperature of the outside air of the vehicle (hereinafter referred to as the outside air temperature), the amount of solar radiation into the passenger compartment, the cooling water temperature of the engine E, and the evaporator 3
Based on the outlet temperature of the wake side air flow of 0, etc., the blower motor 21 is subjected to various kinds of calculation processing such as calculation processing of the required outlet temperature Tao into the vehicle compartment and the opening degree of the air mix damper 30.
Also, the servo motor 41 is controlled, and arithmetic processing necessary for controlling the electromagnetic clutch 80 by the electromagnetic clutch control device 150 described later is performed.

The electromagnetic clutch control device 150, as shown in FIG. 2, is a refrigerant pressure sensor 15 as a refrigerant pressure detecting means.
0a, the rotation speed sensor 150b, the refrigerant pressure sensor 150a, the rotation speed sensor 150b, and the electromagnetic clutch 80.
And a control circuit 150c connected to the ECU 120. The refrigerant pressure sensor 150a is attached to the pipe P2 of the refrigeration cycle R in order to detect an abnormally high pressure or an abnormally low pressure of the refrigeration cycle. The refrigerant pressure sensor 150a is a compressor 6 that flows in the pipe P2.
The pressure of the discharged refrigerant from 0 is detected to generate a refrigerant pressure detection signal. The rotation speed sensor 150b detects the rotation speed of the cam shaft in the distributor of the engine E as the rotation speed Ne of the engine E and generates a rotation speed detection signal.

As shown in FIG. 2, the control circuit 150c includes a filter 151. The filter 151 removes high frequency components and DC components from the frequency components of the refrigerant pressure detection signal from the refrigerant pressure sensor 150a. Then, the remaining frequency component is generated as a refrigerant pressure filter signal. The waveform shaper 152 waveform-shapes the refrigerant pressure filter signal from the filter 151 and generates it as a refrigerant pressure waveform shaping signal. The filter 153 removes the high frequency component and the DC component from the frequency components of the rotation speed detection signal from the rotation speed sensor 150b, and generates the remaining frequency components as a rotation speed filter signal. The waveform shaper 154 waveform-shapes the rotation speed filter signal from the filter 153 and generates it as a rotation speed waveform shaping signal. The microcomputer 155 executes the computer program according to the flow charts shown in FIGS. 3 and 4, and the ECU 120 and both filters 151, 15
3. This is executed in cooperation with both waveform shapers 152 and 154, and during this execution, arithmetic processing necessary for drive control of the drive circuit 156 connected to the electromagnetic clutch 80 is performed. The drive circuit 156 engages or disengages the electromagnetic clutch 80 under the control of the microcomputer 155.

In the first embodiment constructed as described above, if the ECU 120 and the electromagnetic clutch control device 150 are operated under the operation of the engine E, the ECU 12
0 is the required outlet temperature Tao into the vehicle interior and the air mix damper 30 based on the temperature set by the temperature setter 130, the inside temperature detected by the sensor group 140, the outside temperature detected, the amount of solar radiation detected, the detected cooling water temperature, the detected outlet temperature, etc.
The blower motor 21 and the servo motor 41 are controlled by various kinds of calculation processing such as the calculation of the opening degree, and the calculation processing necessary for controlling the electromagnetic clutch 80 by the electromagnetic clutch control device 150 is performed. In addition, in such arithmetic processing, the ECU 120 causes the electromagnetic clutch 8 to operate as necessary.
The control circuit 1 outputs an engagement command signal necessary to command the engagement of 0.
It is output to the microcomputer 155 of 50c.

As described above, the electromagnetic clutch control device 150
Is activated, the microcomputer 155
According to the flowcharts of FIGS. 3 and 4, execution of the computer program is started in step 200, initialization processing is performed in step 201, and the clock data D is set to D = 0. If no engagement command signal is generated from the ECU 120 at this stage, the microcomputer 15
5 determines “NO” in step 210 based on the determination that there is no request to engage the electromagnetic clutch 80, that is, no request to drive the compressor 60.

After that, when an engagement command signal is generated from the ECU 120, the microcomputer 155 determines "YES" in step 210, and in step 211, outputs the engagement output required to engage the electromagnetic clutch 80. A signal is generated and in response, drive circuit 156 engages electromagnetic clutch 80. Therefore, the compressor 60 rotates by receiving power from the engine E via the pulley mechanism 70 and the electromagnetic clutch 80. As the compressor 60 rotates, it sucks the refrigerant from the evaporator 30 through the pipe P1 and compresses it, and discharges the compressed refrigerant to the condenser 90 through the pipe P2. Then, when the compressed refrigerant discharged from the compressor 60 is condensed by the condenser 90, the receiver 100 separates the condensed refrigerant into gas and liquid, and uses the liquid layer component as a circulating refrigerant to expand the expansion valve 110.
Flow into.

Then, the expansion valve 110 expands the inflowing refrigerant and causes it to flow into the evaporator 30 as the expansion refrigerant. Therefore, the evaporator 30 cools the air flow blown from the blower 20 and causes it to flow toward the air mix damper 40. Next, this air mix damper 4
0 indicates the flow rate of the cooling air flow from the evaporator 30 into the heater core 50 and the heater core 5 according to the opening degree.
Adjust the bypass amount for 0. Therefore, the inflow air flow to the heater core 50 is heated by the heater core 50 and flows to the downstream side, while the bypass cooling air flow to the heater core 50 flows to the downstream side as it is. As a result, both flowing air streams are mixed and blown out into the vehicle interior from the air duct 10 as a blown air stream.

When the calculation processing in step 211 is completed as described above, the microcomputer 155 calculates the rotation speed Ne of the engine E based on the rotation speed waveform shaping signal from the waveform shaper 154 in step 212, and the step At 213, the level of the refrigerant pressure waveform shaping signal from the waveform shaper 152 is digitally converted into the refrigerant pressure Vp, and the computer program proceeds to step 214. In such a case, the refrigerant pressure detected by the refrigerant pressure sensor 150a fluctuates so as to show a peak each time a predetermined pulsation cycle T elapses, as shown in FIG. Further, the refrigerant pressure Vp in step 213 is substantially constant when the compressor 60 is locked, as shown in FIG.

When the computer program proceeds to step 214 as described above, the microcomputer 155 calculates the pulsation cycle T based on the time interval between the pair of consecutive peaks of the refrigerant pressure Vp in step 213 and calculates the computer program. To step 215. In step 215, the microcomputer 155
Is the refrigerant pressure V detected by the refrigerant pressure sensor 150a.
Digitally convert to D and advance computer program to step 220. Step 21 at this stage
If the refrigerant pressure VD obtained in 5 is lower than the predetermined abnormal high pressure VH and higher than the predetermined abnormal low pressure VL, that is, the compressor 60
Is operating normally, the microcomputer 155
However, it is determined to be “YES” in step 220. on the other hand,
When the refrigerant pressure VD is higher than the predetermined abnormal high pressure VH or lower than the predetermined abnormal low pressure VL, that is, when the refrigeration cycle is abnormal high pressure or abnormal low pressure, the microcomputer 155 returns “NO” in step 220. Determine. However, the above-mentioned predetermined abnormal high pressure VH and predetermined abnormal low pressure VL
Are stored in advance in the ROM of the microcomputer 155.

When the determination in step 220 is "YES" as described above, the microcomputer 1
55 in step 221 according to the pulsation cycle T in step 214 based on the following relational expression of the compressor 1
Of the compressor 80 according to the pulley ratio Pratio and the rotation speed Ne in step 212, and the rotation speed Nco of the compressor 80, and The slip S is calculated on the basis of the relational expression of the following Expression 3 according to the rotation speed Nco and the actual rotation speed Nca.

[0022]

## EQU1 ## Nca = (1 / T) (r.p.m.)

[0023]

[Equation 2] Nco = Ne · Pratio

[0024]

## EQU00003 ## S = Nca / Nco However, in the relational expression of Equation 1, the actual rotation speed Nca represents the actual rotation speed of the compressor 30. In the relational expression of Formula 2, the rotation speed Nco represents the rotation speed of the compressor 80 when there is no slip. Further, the pulley ratio Pratio represents the ratio of the number of rotations of the pulley 72 of the pulley mechanism 70 to the pulley 71. The relational expressions of the expressions 1 to 3 are stored in advance in the ROM of the microcomputer 155 together with the pulley ratio Pratio.

When the arithmetic processing in step 221 is completed in this way, the microcomputer 155
In step 230, the slip S in step 221 is compared and determined with the predetermined slip SL. In such a case, the predetermined slip SL represents a value corresponding to a state in which the belt 73 of the pulley mechanism 70 is slipping and idling, or a state in which the compressor 60 is locked, and is stored in advance in the ROM of the microcomputer 155. In this embodiment, step 230 constitutes an operating condition monitoring means. If the slip S is equal to or larger than the predetermined slip SL, the microcomputer 155 determines "N" in step 230.
O ”, and in step 231, the time measurement data D is D =
Set 0 to computer program step 21
Return to 0.

On the other hand, the determination in step 230 is "Y".
In the case of “ES”, that is, when the belt 73 is slipping and idling or the compressor 60 is locked, the microcomputer 155 causes the step 2
At 32, the timekeeping data D is updated to D = D + 1 based on D = 0 in step 201. Then, in step 240, the microcomputer 155 determines whether the count data D is equal to or more than the predetermined data Dset. However, the predetermined data Dset corresponds to the time required to correctly determine that the slip S is equal to or larger than the predetermined slip SL without being affected by a disturbance such as noise.
(Seconds), R of the microcomputer 155
Pre-stored in the OM.

At this stage, the count data D is the predetermined data Dse.
If it is less than t, the microcomputer 155 determines “NO” in step 240. After that, step 2
If the determination in step 240 is “YES” while repeating the addition and update of the count data D in 32, the microcomputer 155 stops the generation of the engagement output signal in step 241, and drives in response to this. Circuit 156 disengages electromagnetic clutch 80. Therefore, the compressor 60 is cut off from the power from the engine E and is brought into a stopped state. Note that in this embodiment, step 24
1 constitutes a stopping means.

If the determination in step 220 is "NO", the microcomputer 15
5 advances the computer program to step 241 to disengage the electromagnetic clutch 80 as described above. As a result, the compressor 60 is shut off from the power from the engine E and is brought into a stopped state. If the determination in step 210 is “NO”, the microcomputer 15
5 advances the computer program to step 242.

As described above, in the first embodiment, when the compressor 60 is monitored for an abnormality such as a lock and the compressor 60 is stopped when the abnormality occurs, the compression is performed. In order to effectively utilize the fact that the presence / absence of abnormality of the machine 60 is closely related to the change in the discharge refrigerant pressure, the pipe P
The refrigerant pressure sensor 150a for detecting the refrigerant pressure discharged in 2 is adopted, the pulsation cycle T of the refrigerant pressure detected by the refrigerant pressure sensor 150a is calculated, and the compressor is calculated from the calculated pulsation cycle T based on the relational expression of Formula 1. The actual rotation speed Nca of 60 is calculated, and the rotation speed Nco is calculated based on the relational expression of Expression 2 as the rotation speed Ne of the engine E.
And the pulley ratio Pratio, and the slippage S is calculated according to the actual rotational speed Nca and the rotational speed Nco based on the relational expression of Equation 3. Then, when the slip S is equal to or larger than the predetermined slip SL, the electromagnetic clutch 80 is disengaged and the compressor 60 is driven by the engine E based on the judgment that the compressor 60 has an abnormality such as a lock. Shut off from. As described above, in detecting the rotation state of the compressor 60, the existing refrigerant pressure sensor 150a is adopted instead of the rotation sensor such as the electromagnetic pickup, so that the number of rotation sensors such as the electromagnetic pickup is minimized. Thus, the slip S of the compressor 60 can be calculated, and the abnormality determination such as the lock of the compressor 60 and the accompanying stop of the compressor 60 can be properly ensured while preventing the cost increase. In such a case, the electromagnetic clutch 80 is disengaged in step 241 after the determination of “YES” in step 240, so that the electromagnetic clutch 80 can be disengaged without error without being affected by disturbance or the like. Further, unlike the conventional case, it is not necessary to provide a refrigerant pressure sensor in the compressor 60, so that the external dimensions of the compressor 60 can be reduced.

Next, a second embodiment of the present invention will be described with reference to FIG. 6. In this second embodiment, both filters 15 in the control circuit 150c described in the first embodiment will be described.
1 and 153, both the waveform shapers 152 and 154, and the microcomputer 155 are replaced by the control circuit shown in FIG. This control circuit has both filters 161a and 161b. The filter 161a is the filter 1 described in the first embodiment.
Similar to 51, a refrigerant pressure filter signal is generated in response to the refrigerant pressure detection signal from the refrigerant pressure sensor 161a. on the other hand,
Like the filter 153 described in the first embodiment, the filter 161b generates a rotation speed filter signal in response to the rotation speed detection signal from the rotation speed sensor 150b.

The signal amplifier circuit 162a includes a filter 161.
The refrigerant pressure filter signal from a is amplified to generate a refrigerant pressure amplification signal. On the other hand, the signal amplification circuit 162b outputs the rotation speed filter signal from the filter 161b to the pulley ratio Pratio.
It is amplified only to generate a rotation speed amplified signal. The AND gate 163 receives the rotation speed amplification signal from the signal amplification circuit 162b and, at the same time, the ECU 1 described in the first embodiment.
The engagement command signal from 20 is received through the waveform shaper 163a, and a gate signal is output at a high level. Also, A
The gate signal from the ND gate 163 becomes low level due to the change of the engagement command signal from the ECU 120 to low level.

The signal level comparison circuit 164a compares the level of the refrigerant pressure amplified signal from the signal amplification circuit 162a with the refrigerant pressure reference level and sequentially generates pulse signals. On the other hand, the signal level comparison circuit 164b includes the AND gate 16
The level of the gate signal from 3 is compared with the rotation speed reference level, and pulse signals are sequentially generated. However, in the second embodiment, each signal level comparison circuit 164a, 164b
As for, 74HC123 made by Toshiba is adopted. Frequency-voltage conversion circuit 165a (hereinafter, F-V conversion circuit 16
5a) converts the frequency corresponding to the cycle (corresponding to the pulsation cycle T) of the pulse signal from the signal level comparison circuit 164a into a voltage proportional to this. On the other hand, the frequency-voltage conversion circuit 165b (hereinafter, F-V conversion circuit 165
b) converts a frequency (proportional to the rotation speed Ne) corresponding to the cycle of the pulse signal from the signal level comparison circuit 164b into a voltage proportional to the frequency.

The signal level comparison circuit 166 converts the converted voltage from the FV conversion circuit 165a into an FV conversion circuit 165b.
Compare with the converted voltage from. Then, the FV conversion circuit 1
When the converted voltage from 65a is higher than the converted voltage from the FV conversion circuit 165b, the signal level comparison circuit 166 generates a comparison signal at a high level. Further, the comparison signal is the converted voltage F-V from the F-V conversion circuit 165a.
When it is lower than the converted voltage from the conversion circuit 165b, it becomes low level. In this case, when the comparison signal from the signal level comparison circuit 166 is at a high level, the actual rotation speed Nca of the compressor 60 is abnormally lower than the rotation speed Nco, that is,
This corresponds to the locked state of the compressor 60. The other structure is similar to that of the first embodiment.

In the second embodiment constructed as described above, the engine E and the ECU 12 are the same as in the first embodiment.
It is assumed that the electromagnetic clutch 80 is in the engaged state in the operating state of 0. In such a state, the filter 161a generates the refrigerant pressure filter signal in response to the refrigerant pressure detection signal from the refrigerant pressure sensor 161a, while the filter 161b responds to the rotation speed detection signal from the rotation speed sensor 150b. When the rotation speed filter signal is generated by the signal amplification circuit 162,
a amplifies the refrigerant pressure filter signal from the filter 161a to generate a refrigerant pressure amplification signal, while the signal amplification circuit 1
62b amplifies the rotation speed filter signal from the filter 161b by the pulley ratio Pratio to generate a rotation speed amplified signal. Then, the AND gate 163 changes the signal amplification circuit 1
A gate signal is output at a high level in response to the rotation speed amplification signal from 62b and the engagement command signal from the ECU 120 described in the first embodiment. Further, the signal level comparison circuit 164a compares the level of the refrigerant pressure amplified signal from the signal amplification circuit 162a with the refrigerant pressure reference level to sequentially generate pulse signals, while the signal level comparison circuit 16
4b compares the level of the gate signal from the AND gate 163 with the rotation speed reference level to sequentially generate pulse signals. Then, the F-V conversion circuit 165a converts the frequency corresponding to the cycle of the pulse signal from the signal level comparison circuit 164a into a voltage proportional to this, while the F-
The V conversion circuit 165b converts the frequency corresponding to the cycle of the pulse signal from the signal level comparison circuit 164b into a voltage proportional to this.

After that, the signal level comparison circuit 166 changes the F level.
The converted voltage from the −V conversion circuit 165a is compared with the converted voltage from the FV conversion circuit 165b. At this time, F-V
The converted voltage from the conversion circuit 165a is the FV conversion circuit 16
If it is lower than the converted voltage from 5b, the signal level comparison circuit 166 generates a comparison signal at a high level, and in response thereto, the drive circuit 156 responds to the low level comparison signal from the signal level comparison circuit 166. Then the electromagnetic clutch 80
Dissociate. As a result, also in the second embodiment,
As in the first embodiment, the refrigerant pressure sensor 150a is used instead of the rotation sensor such as the electromagnetic pickup to minimize the number of rotation sensors such as the electromagnetic pickup to prevent the cost increase. While the compressor 6
An abnormality such as 0 lock is monitored, and the compressor 60 can be reliably disconnected from the power of the engine E by disengaging the electromagnetic clutch 80 when the abnormality occurs.

In implementing the present invention, the ECU 120 and the electromagnetic clutch control device 150 are integrated with each other without making the ECU 120 and the electromagnetic clutch control device 150 separate as described in each of the above embodiments. ECU1
The function of the electromagnetic clutch controller 150 may be the same as that of the electromagnetic clutch controller 150.

In each of the above embodiments, the compressor 60 having the electromagnetic clutch 80 adopts the refrigeration cycle R. However, instead of this, an inverter-controlled compressor is adopted in the refrigeration cycle R. Then, an abnormality such as a lock of the compressor may be monitored, and the power transmission to the compressor may be stopped by the inverter when the abnormality occurs.

Further, in carrying out the present invention, the air conditioner of each of the above embodiments may be either an automatic type or a manual type, and is not limited to the refrigeration cycle of the vehicle air conditioner, but may be a vehicle refrigerating device. Alternatively, the present invention may be applied to and implemented in a refrigeration cycle of an air conditioning device for general buildings, a refrigerating device, or a refrigerating device.

Further, in the first embodiment, the lock determination of the compressor 60 is made based on the detection results of both the refrigerant pressure sensor 150a and the rotation speed sensor 150b, but instead of this, the refrigerant pressure sensor 150a. The lock determination of the compressor 60 may be performed only by the determination. In this case, the refrigerant pressure detected by the refrigerant pressure sensor 150a is the compressor 60.
The lock determination of the compressor 60 is performed by utilizing the decrease in the lock state.

Further, in carrying out the present invention, the compressor 60 may be of any type such as a swash plate type or a scroll type, and the drive source of the compressor 60 is the engine E.
However, the motor may be an electric motor.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a detailed circuit diagram of the electromagnetic clutch control device of FIG.

FIG. 3 is a front part of a flowchart showing the operation of the microcomputer of FIG.

FIG. 4 is a latter part of the flowchart.

5 is a graph showing a temporal change in the refrigerant pressure detected by the refrigerant pressure sensor in relation to the normal state of the compressor of FIG. 1 and an abnormal state such as lock.

FIG. 6 is a main part electric circuit diagram showing a second embodiment of the present invention.

[Explanation of symbols]

E ... Engine, P2 ... Piping, R ... Refrigeration cycle, 60 ...
Compressor, 70 ... Pulley mechanism, 80 ... Electromagnetic clutch, 15
0 ... Electromagnetic clutch control device, 150a ... Refrigerant pressure sensor,
150c ... Control circuit, 155 ... Microcomputer,
161a, 161b ... Signal amplification circuits, 164a, 164
b, 166 ... Signal level comparison circuit, 165a, 165b
... FV conversion circuit.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yuji Honda, 1-1, Showa-cho, Kariya city, Aichi Prefecture, Nihon Denso Co., Ltd. (72) Inventor, Katsuhiko Samukawa, 1-1, Showa-cho, Kariya city, Aichi prefecture Incorporated (72) Inventor Toshihide Takechi, 1-1, Showa-cho, Kariya, Aichi Prefecture, Nihon Denso Co., Ltd. (72) Inventor, Ryozo Okumura, 1-1, Showa-cho, Kariya, Aichi Nidec Corporation ( 72) Inventor Sugimitsu, 1-1, Showa-cho, Kariya city, Aichi prefecture, Nihondenso Co., Ltd.

Claims (2)

[Claims] 1. A compressor, which receives power from a drive source to compress and discharge a refrigerant, and power transmission means for transmitting power from the drive source to the compressor according to an operation. Refrigeration cycle for circulating the compressed compressed refrigerant from the compressor, refrigerant pressure detecting means for detecting the pressure of the compressed compressed refrigerant from the compressor, and the drive source of the compressor based on the refrigerant pressure detected by the refrigerant pressure detecting means. And a working condition monitoring means for monitoring the working condition of the compressor for the refrigeration cycle. 2. A stop means for stopping the operation of the power transmission means when the monitoring result of the operation state monitoring means becomes a predetermined abnormal operation state of the compressor, and the power transmission means stops the operation. 2. The compressor operation monitoring device of the refrigeration cycle according to claim 1, wherein the transmission of power to the compressor is cut off by the above.