JPS6122226B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a compressor control device for a refrigerator, and is suitable for use in, for example, an automobile air conditioner.

[Conventional technology]

Conventional refrigerators used in automobile air conditioners do not take into account protection from refrigerant leaks, so there is a risk that the refrigerator may be operated without refrigerant, and in this case, the lubrication of the compressor of the refrigerator may be insufficient. There is a problem in that oil accumulates in a receiver or the like during the refrigeration cycle, causing a shortage of lubricating oil in the compressor, resulting in seizure of the compressor. In particular, in refrigerators that are equipped with an evaporation pressure adjustment valve in the system between the evaporator and compressor, refrigerant leaks can cause a shortage of refrigerant, and this adjustment valve closes to increase the evaporation pressure of the evaporator. Therefore, the above problem will be further exacerbated.

For this reason, in the conventional Japanese Patent Application Laid-Open No. 52-59353, as shown in FIG.
The temperature of the intake air and the temperature of the outlet air are detected by temperature sensors 101 and 102, and both sensors 10
When the temperature difference between the detected temperatures 1 and 102 falls within a predetermined value, the comparator 103 outputs an output signal, the relay contact 104 turns on, energizes the delay device 105, and after a predetermined period of time, the movable contact 106 of the relay turns on.
A device has been proposed in which the normally closed fixed contact 107 is switched and connected to the normally open fixed contact 108 to stop the compressor 109 and turn on the indicator lamp 110. According to this device, it is possible to prevent the refrigeration cycle from being operated with insufficient refrigerant.

By the way, the compressor 109 of the refrigeration cycle in the automobile air conditioner automatically operates when the outlet air temperature of the evaporator 100 falls below the set temperature in order to prevent frosting of the evaporator 100 and control the temperature of the blown air. In addition, when the outside temperature drops to the set temperature near 0℃, there is no need to operate the refrigeration cycle, so in this case as well, compressor 1 is stopped.
The operation of 09 is automatically stopped.

In addition, in order to avoid a problem in which the rotation speed of the internal combustion engine that drives the compressor 109 decreases for some reason and the internal combustion engine stops, when the rotation speed of the internal combustion engine decreases to a set rotation speed, the compressor 109 starts operating. Many control systems are also used in which the engine is automatically stopped.

[Problem that the invention seeks to solve]

In this way, in the refrigeration cycle for automobile air conditioning,
The operation of the compressor is automatically controlled intermittently for various reasons during the operation of the air conditioner, but in the conventional device described in the above publication, the control circuits 103 and 105 for detecting refrigerant shortage are Since power is supplied via the operation/intermittent switch 111 (specifically, the blown air temperature switch of the ventilation duct), even if the refrigerant shortage indicator lamp 110 is turned on due to detection of refrigerant shortage, the above-mentioned When the operation intermittent switch 111 is turned off, the indicator lamp 1
10 goes out again. Therefore, the user is given the misunderstanding that the refrigerant shortage situation has been resolved, which is extremely undesirable from the viewpoint of the abnormality display function.

Furthermore, when the operation intermittent switch 11 is turned off, the power to the delay device 105 is cut off.
The heat wire 112 cools the bimetal contact 1
13 returns to the open state, and the relay contact 106 returns to the normally closed fixed contact 107 side. Therefore,
When the switch 111 returns to the on state due to a change in air conditioning conditions, a problem occurs in that the compressor 109 operates and the indicator lamp 110 continues to be turned off even though there is a refrigerant shortage.

Therefore, in view of the above points, the present invention reliably maintains the stopped state of the compressor and the state displayed by the display means, without being affected by the presence or absence of a temperature signal or engine speed signal, once refrigerant shortage is detected. The purpose is to

[Means for solving problems]

In order to achieve the above object, the present invention employs the following technical means. That is, the first invention includes a refrigerant shortage signal generating means that generates a signal when the amount of refrigerant in the refrigeration cycle of the refrigerator decreases below a set value, and a temperature such as evaporator outlet air temperature, outside air temperature, etc. that falls below the set temperature. a temperature signal generating means that generates a signal when the temperature decreases; a compressor operation/intermittent means that stops the compressor when either of the signal generating means generates a signal; a display means that displays a refrigerant shortage; and the refrigerant shortage signal. Receives a signal from the generating means,
A technical means is adopted that includes a control means that drives the display means to a display state and maintains this display state and the stopped state of the compressor regardless of the presence or absence of a signal from the temperature signal generation means.

In the second invention, the refrigerant shortage signal generating means generates a signal when the amount of refrigerant in the refrigeration cycle of the refrigerator decreases below a set value, and when the rotation speed of the internal combustion engine that drives the compressor decreases below the set value. an engine rotation speed signal generating means for generating a signal; a compressor operation intermittent means for disconnecting the compressor from the internal combustion engine and stopping the compressor when either of the signal generating means generates a signal; generating means for indicating refrigerant shortage; and receiving a signal from the refrigerant shortage signal generating means;
A technical means is adopted for driving the display means to a display state, and comprising a control means for connecting this display state and a stopped state of the compressor regardless of the presence or absence of a signal from the engine rotation speed signal generation means. .

In the third invention, there is provided a refrigerant shortage signal generating means that generates a signal when the amount of refrigerant in the refrigeration cycle of the refrigerator decreases below a set value; Temperature signal generation means that generates a signal; engine rotation speed signal generation means that generates a signal when the rotation speed of the internal combustion engine that drives the compressor falls below a set value; and one of these three signal generation means that generates a signal. compressor operation intermittent means for disconnecting the compressor and the internal combustion engine to stop the compressor when such occurrence occurs; display means for displaying refrigerant shortage; receiving a signal from the refrigerant shortage signal generating means;
A technique comprising control means that drives the display means to a display state and maintains this display state and the stopped state of the compressor regardless of the presence or absence of signals from the temperature signal generation means and the engine rotation speed signal generation means. Adopt practical means.

〔Example〕

The present invention will be described below with reference to embodiments shown in the drawings. 1 to 5 show common embodiments of the first invention, second invention, and third invention, and FIG. 1 shows a schematic diagram when the invention is applied to an automobile cooling device. Reference numeral 1 denotes an engine rotation speed signal circuit section, which outputs a signal when the rotation speed of the automobile internal combustion engine 3 that drives the compressor 2 of the refrigeration cycle falls below a set value. By inputting the rectangular wave voltage generated in the primary circuit of the engine, a signal corresponding to the engine speed is output. Reference numeral 5 denotes a temperature signal circuit section which outputs a signal when the temperature of the outlet air of the evaporator 6 (shown in FIG. 2) of the refrigeration cycle, the outside air temperature, etc. falls below a set temperature. 7 is a temperature detector for supplying a temperature detection signal to the temperature signal circuit section 5, and is made of a heat-sensitive resistance element such as a thermistor.
In this example, it is installed on the air outlet side of the evaporator 6 as shown in FIG. Reference numeral 8 denotes a refrigerant shortage signal circuit section, which controls a refrigerant shortage signal generating means that generates a signal when the amount of refrigerant in the refrigeration cycle decreases below a set value, and a refrigerant shortage display means upon receiving the signal from this means. and a control means. Reference numeral 9 denotes a refrigerant amount detector for supplying a refrigerant amount detection signal to the refrigerant shortage signal circuit section 8, and is composed of a negative characteristic thermistor for detecting the degree of dryness of the refrigerant. The refrigerant amount detector 9 is installed in the middle of the low-pressure pipe 11 on the downstream side of the expansion valve 10, as shown in FIGS. 2, 3, and 4.

Reference numeral 12 denotes a switching circuit that serves as a compressor operation/intermittent means, and when any of the three signal circuit sections 1, 5, and 8 generates a signal, it cuts off the power to the electromagnetic clutch 13 of the compressor 2 and switches the compressor 2 on and off. This is to stop the operation. The electromagnetic clutch 13 connects and disconnects the compressor 2 and internal combustion engine 3. 14
15 is an on-vehicle power storage battery, and 16 is a relay of the switching circuit 12, which is composed of a coil 16a and a normally open contact 16b. In FIG. 2, 17 is a condenser, 17a is a cooling fan, 18 is a receiver, and 6a is an evaporator fan. In Figure 3, 6b
6c is a refrigerant distribution distributor provided on the refrigerant inlet side of the evaporator 6, and an accumulator 6c is provided on the refrigerant outlet side of the evaporator 6. In FIG. 4, 9a is a negative characteristic thermistor that detects the dryness of the refrigerant using self-heating, and this thermistor 9a indicates that when the amount of refrigerant is normal, the dryness of the refrigerant is small and the ratio of liquid refrigerant is low. Since the refrigerant is large in size, even if it self-generates heat, it is cooled by a liquid refrigerant with a large heat capacity, and its resistance increases.On the other hand, when there is a shortage of refrigerant, the dryness of the refrigerant increases, the ratio of gas refrigerant increases, and the heat capacity of the refrigerant decreases. Therefore, the degree of dryness of the refrigerant is detected by utilizing the fact that the heat radiation amount of the thermistor 9a decreases and the resistance value decreases. That is, the thermistor 9a detects the degree of dryness of the refrigerant by changing the amount of heat released by the thermistor 9a due to a change in the heat capacity of the refrigerant due to a change in the amount of refrigerant, and changing its resistance value. As shown in FIG. 4, this thermistor 9a is located at a deep part outside the inner diameter of the pipe 11 downstream of the expansion valve 10, and is installed so as not to be directly hit by the flow of refrigerant.

FIG. 5 shows a specific electric circuit of the circuit section of the device of the present invention, where the input terminal A of the engine rotation speed signal circuit section 1 is connected to an ignition coil that generates a rectangular wave voltage proportional to the rotation speed of the internal combustion engine 3. It is connected to the primary side circuit of No. 4 and takes out the rectangular wave voltage. resistance 19
a, 19b, and a capacitor 20 constitute a filter circuit that removes harmful pulse voltage contained in the rectangular wave. Transistor 21, capacitor 2
2, 23, diodes 24, 25, and resistor 26 constitute a DA conversion circuit that amplifies the rectangular wave, performs DA conversion, and generates a DC output voltage at point 27 in accordance with the engine speed. Comparator 28, resistor 29,
30, the transistor 31 constitutes a voltage discrimination circuit that determines whether the voltage generated at the point 27 is above or below a set value, and sets the potential at the point 32 to a low potential in the following cases.

Next, the configuration of the temperature signal circuit section 5 will be described. It has a bridge circuit composed of the thermistor 7a of the temperature detector 7, a resistor 33, and resistors 34 and 35, and the potential difference between the connection points 36 and 37 of this bridge circuit. are compared by the comparator 38, and this comparator 38
The output is amplified by transistors 39 and 40.

Next, the refrigerant shortage signal circuit section 8 will be explained. In this example, the refrigerant shortage signal circuit section 8 includes a dryness determination circuit 41, a delay circuit 42, and an amplifier circuit 4.
These circuits 41, 42,
43. A refrigerant shortage signal generating means and a control means are constituted by the mutual coupling relationship. Both means will become clear from the explanation of operation below. The dryness level determination circuit 41 is installed in an instrument panel or the like in the vehicle interior, and detects the potential difference between connection points 47 and 48 of a bridge circuit constituted by an indicator lamp 44 serving as a means for indicating refrigerant shortage and a thermistor 9a and resistors 45 and 46. A switching transistor 50 which has a comparator 49 for comparison and conducts between the connection point 47 and ground when there is a shortage of refrigerant.
It is equipped with The delay circuit 42 has a capacitor 53 connected to the output end of the comparator 49 via a resistor 51 and a capacitor 53 for charging the charge at the connection point 52, and a connection point 55 connected to the connection point 52 via a resistor 54. A comparator 59 is provided that compares the reference potential of a connection point 58 between the contacts 56 and 57 and outputs the result. The amplifier circuit 43 includes transistors 60, 60 for amplifying the output of the comparator 59, and a driving transistor 62 for the switching transistor 50 of the dryness determination circuit 41. The collector of this transistor 62 is connected to the activation switch 14 via a line 80 to receive power.

In addition to the refrigerant shortage signal generation function, the refrigerant shortage signal circuit section 8 also performs dryness determination when the engine speed signal circuit section 1 or the temperature signal circuit section 5 sends a stop signal for the compressor 2 to the switching circuit 12. A switching transistor 63 for cutting off power to the circuit 41 and a driving transistor 64 for this transistor 63 are provided. This configuration is such that when the engine speed or the temperature detected by the thermistor 7a falls below the set value and the operation of the compressor 2 is stopped, the function of the refrigerant shortage signal circuit section 8 is stopped and the function is restarted. This is to enable the compressor 2 to operate when the engine speed or the temperature detected by the thermistor 7a exceeds a set value. In other words, even if the refrigeration cycle is normally filled with refrigerant, the refrigerant shortage signal circuit 8 determines that there is a refrigerant shortage because there is no refrigerant flow when the compressor 2 stops, and the compressor 2 is stopped. This is because it will cause it to stop.

In order to perform the above action, the base of the transistor 64 is connected to diodes 65a, 65b, 6
6 and 67 and resistors 68 and 69 to the output terminal of the comparator 28 of the engine speed signal circuit section 1 and the collector of the transistor 39 of the temperature signal circuit section 5. On the other hand, the base of the transistor 60 of the amplifier circuit 43 is also connected to the output terminal of the comparator 28 and the transistor 3 via the diode 70, the diodes 66, 67, and the resistors 68, 69.
9 collector.

Next, the switching circuit 12 will be explained. This circuit 12 consists of three signal circuit sections 1, 5, and 8.
It consists of a switching transistor 71 whose base is connected to the collector of each of the output transistors 31, 40, and 61, the aforementioned relay 16 controlled by this transistor 71, and a diode 72 for absorbing the induced voltage of the relay coil 16a.

73 is a control box that houses the engine speed signal circuit section 1, the temperature signal circuit section 5, the refrigerant shortage signal circuit section 8, and the switching circuit section 12 all in one body;
It is installed in a location such as the bottom of the instrument panel inside the vehicle. Note that the relay 16 of the switching circuit section 12 may be provided independently outside the control box 73 if necessary.

The operation of the device of the present invention in the above configuration will be explained.

Now, when the rotation speed of the internal combustion engine 3 falls below the set value and the potential at the connection point 27 of the engine speed signal circuit section 1 becomes below the set value, the output voltage of the comparator 28 becomes high, and as a result, the output voltage of the transistor 31 is conductive, so its collector potential, that is, the connection point 32, becomes a low potential. Therefore, the switching transistor 71 of the switching circuit 12 is cut off, and the contact 16b of the relay 16 is changed from the closed state to the open state, so that the power to the electromagnetic clutch 13 is cut off, the compressor 2 is stopped, and the internal combustion engine is turned off. Since the load on engine 3 is reduced, it is possible to prevent the internal combustion engine 3 from stopping. At the same time, the output voltage of the comparator 28 increases, so that the base potential of the transistor 64 of the refrigerant shortage signal circuit section 8 increases to the level of the diode 6.
7, 65a, and 65b, and the transistor 64 becomes conductive, the base potential of the switching transistor 63 becomes a low potential, and this transistor 63 is cut off, so that the refrigerant shortage detection thermistor 9a is also energized. The refrigerant shortage signal circuit section 8 ceases to operate.

Next, when the rotation speed of the internal combustion engine 3 increases again and the potential at the connection point 27 exceeds the set value, the comparator 28
The output voltage of transistor 31 becomes low level.
is cut off, the connection point 32 becomes high potential, the switching transistor 71 becomes conductive, and the contact 16b of the relay 16 becomes closed, so the compressor 2 is operated again. At the same time, the base potential of the transistor 64 also becomes low, so this transistor 64 is cut off, the transistor 63 becomes conductive, and the refrigerant shortage signal circuit section 8
begins to operate.

Next, an explanation will be given of the operation when the outlet air temperature of the evaporator 6, the outside air temperature, etc. are below the set temperature. As these temperatures decrease, the resistance of the thermistor 7a of the temperature detector 7 increases, so
The potential at the connection point 36 between the thermistor 7a and the resistor 33 increases. Then, when the potential at the connection point 36 becomes higher than the reference potential at the connection point 37, the output potential of the comparator 38 decreases, so the transistor 39 is cut off, its collector potential increases, and the transistor 40 becomes conductive. Therefore, the collector potential of the transistor 40, that is, the potential at the connection point 32 becomes a low potential, and the compressor 2 stops. This makes it possible to control the evaporator 6 to prevent frosting. Furthermore, as the collector potential of the transistor 39 increases as described above, the base potential of the transistor 64 also increases, so that the transistor 64 becomes conductive and the transistor 63 is cut off, causing the refrigerant shortage signal circuit section 8 to operate. will also stop. When the temperature rises again and the potential at the connection point 36 becomes lower than the potential at the connection point 37, the output potential of the comparator 38 becomes high and the collector potential of the transistor 39 becomes a low potential, so the refrigerant shortage signal circuit section 8 is activated. At the same time, compressor 2 also starts operating.

Next, the operation in the case of refrigerant shortage will be explained.
When refrigerant leaks from the refrigeration cycle and a refrigerant shortage occurs, the refrigerant between the expansion valve 10 and the evaporator 6 moves from normal point a to point b along arrow c in the Mollier diagram of FIG. 6 and dries up. It becomes a gas state close to 1 degree, and its heat capacity decreases. As a result, the self-heating type thermistor 9a of the refrigerant amount detector 9
As the cooling rate decreases and the amount of heat dissipated decreases,
It's getting hotter. Since the resistance value of the thermistor 9a decreases as its temperature rises, the potential at the connection point 47 between the thermistor 9a and the lamp 44 decreases, and the connection between this connection point 47 and the resistor 47a decreases. When the potential at point 47' becomes lower than the potential at connection point 48, the output potential of comparator 49 becomes high and charging of capacitor 53 begins. As this charging progresses, the potential at the connection point 52 gradually increases, and the potential at the connection point 55 also increases through the resistor 54, and after a certain period of time, it becomes higher than the reference potential at the connection point 58 obtained by the resistors 56 and 57. When the potential at the connection point 55 becomes high, the potential at the output terminal 74 of the comparator 59 becomes low. Thereby, the transistor 60
is cut off and its collector potential becomes high. Therefore, the transistor 61 becomes conductive, and the collector potential thereof, that is, the potential at the connection point 32 of the switching circuit 12 becomes low, and the operation of the compressor 2 is stopped. Further, as described above, when the collector potential of the transistor 60 becomes high, the transistor 62 also becomes conductive, and the transistor 50 of the dryness determination circuit 41 becomes conductive, so that the lamp 44 lights up to indicate a refrigerant shortage state. At the same time, thermistor 9
The current flowing through the thermistor 9a is reduced, and deterioration due to heat generation of the thermistor 9a can be prevented.

In addition, since the potential at the output end 74 of the comparator 59 becomes low due to lack of refrigerant, in this state of lack of refrigerant, the internal combustion engine speed decreases or the temperature detected by the thermistor 7a decreases. Diodes 66, 67 and diodes 65a, 70
Even if the potential at the connection point 75 increases, current flows through the diode 70 to the comparator 59 side, so the base potential of the transistor 64 does not increase, and therefore, the transistor 64 remains in the cut-off state. Transistor 63 remains conductive. As a result, power continues to be supplied to the dryness determination circuit 41, so that the refrigerant shortage indicator lamp 44 continues to be lit due to the conduction of the transistor 50.
It is possible to maintain the display state of refrigerant shortage and also maintain the stopped state of the compressor 2. This state continues as long as the actuation switch 14 is closed, and is released when the switch 14 is opened.

In this example, as can be understood from the above operation description, in the refrigerant shortage signal circuit section 8, the control means is mainly constituted by transistors 50, 62, 63, 64, etc., and the refrigerant shortage signal is transmitted by other circuit elements. It constitutes the means of generation.

The present invention is not limited to the above-mentioned embodiments and can be implemented in various ways. For example, FIG. 7 shows an example in which the present invention is applied to a refrigerator that does not require a compressor control function based on temperature detection. In this example, the switching circuit 12 is controlled only by the signal from the engine speed signal circuit section 1 and the signal from the refrigerant shortage signal circuit section 8. Therefore, FIG. 7 is an embodiment of only the second invention.

FIG. 8 shows an example in which the present invention is applied to a case where the compressor 2 is operated by a motor 77 energized by an AC power source 76, such as in a residential cooling system, and in this case, it is necessary to detect the engine speed. Therefore, the switching circuit 12 is controlled only by the signal from the temperature signal circuit section 5 and the signal from the refrigerant shortage signal circuit section 8. Therefore, FIG. 8 is an embodiment of only the first invention.

Note that many automotive cooling systems have recently been equipped with an idle-up device that forcibly increases the engine speed during idling when the cooling system is activated. Since there is a case where the rotational speed is not detected, it is possible to use only both the temperature signal circuit section 5 and the refrigerant shortage signal circuit section 8 as in the example shown in FIG.

In addition, the element for detecting the dryness of the refrigerant is not limited to the negative characteristic thermistor 9a as in the above-mentioned embodiment, but also a heat-sensitive element such as a positive characteristic thermistor or a TPC thermistor, or a change in the capacitance of the refrigerant, or a change in the electric conductivity. It is also possible to use an element that detects the degree of dryness based on changes in .
Furthermore, the refrigerant amount detector 9 is not limited to the dryness of the refrigerant, but may also be used to detect the degree of superheating of the refrigerant at the evaporator outlet, the refrigerant liquid level in the receiver 18, etc.

Further, when the detector 9 detects the dryness of the refrigerant as in the above embodiment, its installation location is not limited to the low pressure piping 11 at the outlet of the expansion valve, but may also be installed on the high pressure piping, and the detector 9 may be installed on the expansion valve 10 or the high pressure piping. It may be manufactured integrally with the refrigerant distributor 6b.

〔Effect of the invention〕

The present invention is as explained above, and according to the first invention, when the operation of the compressor is controlled intermittently by both the signal of the refrigerant shortage signal generation means and the signal of the temperature signal generation means, the refrigerant shortage is detected. Detect and once
When the compressor is stopped and the refrigerant shortage display means is driven to the display state, the compressor stop state and the display state of the display means can be reliably maintained without being affected by the presence or absence of a temperature signal, and therefore , problems such as compressor seizure due to refrigerant shortage can be reliably prevented.

According to the second invention, in the compressor 2 driven by the internal combustion engine 3, when the operation of the compressor is controlled intermittently by both the signal from the refrigerant shortage signal generating means and the signal from the engine rotation speed signal generating means. When a refrigerant shortage is detected and the compressor is stopped once and the refrigerant shortage display means is driven to the display state, the compressor stop state and The display means of the display means can be maintained reliably, and problems such as seizure of the compressor due to lack of refrigerant can therefore be reliably prevented.

According to the third invention, when the operation of the compressor is controlled intermittently by the signal of the refrigerant shortage signal generation means, the signal of the temperature signal generation means, and the signal of the engine speed signal generation means, refrigerant shortage is detected. Once detected, the compressor is stopped and the refrigerant shortage display means is driven to the display state. From then on, the compressor stop state and the display means are displayed without being affected by the presence or absence of the temperature signal and engine speed signal. The displayed state can be maintained reliably, and problems such as seizure of the compressor due to lack of refrigerant can be reliably prevented.

[Brief explanation of the drawing]

Figure 1 is a schematic electrical circuit diagram showing one embodiment of the present invention, Figure 2 is a refrigeration cycle diagram in the present invention, Figure 3 is a perspective view of the evaporator portion in the present invention, and Figure 4 is the amount of refrigerant in the present invention. 5 is a specific electric circuit diagram of the present invention, FIG. 6 is a Mollier diagram for explaining the operation of the present invention, and FIGS. 7 and 8 are diagrams showing the installation state of the detector. FIG. 9 is an electrical circuit diagram of a conventional device. 1... Engine speed signal circuit section, 2... Compressor, 3...
Internal combustion engine, 5... Temperature signal circuit section, 6... Evaporator, 8... Refrigerant shortage signal circuit section, 12... Switching circuit forming compressor operation/intermittent means, 13... Electromagnetic clutch, 44... Display lamp forming display means.

Claims (1)

[Scope of Claims] 1. A refrigerant shortage signal generating means that generates a signal when the amount of refrigerant in the refrigeration cycle of the refrigerator decreases below a set value, and a temperature such as evaporator outlet air temperature, outside air temperature, etc. that falls below the set temperature. temperature signal generating means for generating a signal in response; compressor operation continuation means for stopping the compressor when either of the signal generating means generates a signal; display means for displaying refrigerant shortage; and generating the refrigerant shortage signal. receive a signal from the means,
The display means is driven to the display state, and the compressor operation continuation means is disabled from entering the compressor operation state by the signal from the temperature signal generation means, so that the compressor is in the stopped state and the display means is in the stopped state. 1. A compressor control device for a refrigerator, comprising: a control means for maintaining a display state. 2. A refrigerant shortage signal generating means that generates a signal when the amount of refrigerant in the refrigeration cycle of the refrigerator decreases below a set value, and an engine that generates a signal when the rotation speed of the internal combustion engine that drives the compressor falls below the set value. a rotation speed signal generating means; a compressor operation intermittent means for disconnecting the compressor and the internal combustion engine to stop the compressor when either of the signal generating means generates a signal; and displaying a refrigerant shortage. receiving a signal from the display means and the refrigerant shortage signal generation means;
The display means is driven to the display state, and the compressor operation intermittent means is disabled from entering the compressor operation state by a signal from the engine rotation speed signal generation means, so that the compressor is in the stopped state and the display is displayed. 1. A compressor control device for a refrigerator, comprising: control means for maintaining a display state of the means. 3 A refrigerant shortage signal generating means that generates a signal when the amount of refrigerant in the refrigeration cycle of the refrigerator decreases below a set value, and a temperature that generates a signal when the temperature of the evaporator outlet air temperature, outside air temperature, etc. falls below the set temperature. a signal generating means; an engine rotation speed signal generating means for generating a signal when the rotation speed of the internal combustion engine that drives the compressor falls below a set value; and when any of these three signal generating means generates a signal, the compressor compressor operation intermittent means for stopping the compressor by cutting off the connection between the compressor and the internal combustion engine; display means for displaying a refrigerant shortage; and receiving a signal from the refrigerant shortage signal generating means;
The display means is driven to the display state, and the compressor operation intermittent means is disabled from entering the compressor operation state by the signals of the temperature signal generation means and the engine speed signal generation means, so that the compressor is activated. A compressor control device for a refrigerator, comprising: a control means for maintaining the stopped state of the display means and the display state of the display means.