JPH0332487B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control device for a refrigeration cycle for an automobile, and more particularly to a control device for a refrigeration cycle in which the discharge capacity of a compressor is variable.

[Conventional technology]

A conventional air conditioner for an automobile has a vapor compression type refrigeration cycle in which a compressor 1, a condenser 2, a receiver 3, an expansion valve 4, and an evaporator 5 are sequentially connected through refrigerant piping, as shown in FIG. The compressor 1 receives driving force from an automobile engine (not shown) via an electromagnetic clutch 7, and sucks in, compresses and discharges refrigerant. Therefore, as the engine rotational speed increases or decreases, the compressor rotational speed also increases or decreases, and the discharged refrigerant flow rate fluctuates.
Therefore, when the number of revolutions of the compressor increases or the refrigerant load decreases due to a drop in outside temperature, etc., the fin temperature of the evaporator 5, that is, the evaporation temperature of the refrigerant, becomes 0°C or lower. There is a risk that the temperature may drop to a low level, causing frost to form or freeze on the fins.
In this case, the amount of air blown by the blower 8 decreases, resulting in a decrease in cooling capacity. Therefore, in order to prevent this reduction in frost formation and to control the temperature inside the vehicle, the air temperature immediately after the evaporator 5 is detected by a temperature sensor 6 such as a thermistor, and the operating time of the compressor 1 is adjusted. That's what I was doing. That is, the second
As shown in the figure, the control circuit 9 opens and closes the contacts 10a of the relay 10 to connect and disconnect the electromagnetic clutch of the compressor 1, thereby adjusting the operating time of the compressor 1 and controlling the evaporation temperature of the refrigerant. At the same time, the air temperature immediately after the evaporator was controlled.

However, in such a configuration, if the cooling load decreases or the rotation speed of the compressor 1 increases, the compression function becomes excessive and the capacity of the refrigeration cycle exceeds the cooling capacity.
As shown in the figure, the air temperature T immediately after the evaporator 5 decreases and becomes below the set temperature T ₀ at point C. However, due to its heat capacity, the temperature sensor 6 has a time delay as shown in FIG. 3 before the control circuit 9 is activated. That is, during the above-mentioned time period), the air temperature T further decreases and becomes considerably lower than the set temperature T ₀ . Then, when the control circuit 9 operates and the clutch 7 is disengaged at point a, the compressor 1 is stopped, the expansion valve 4 is closed, and the supply of liquid refrigerant to the evaporator 5 is stopped. Then, the internal pressure _P1 of the evaporator 5 increases, and the superheated region of the refrigerant increases, so that the effective heat transfer area of the evaporator 5 decreases.
As a result, the air temperature T immediately after the evaporator 5 rises rapidly, and becomes equal to or higher than the set temperature T ₀ at point d. However, for the same reason as above, there is a time delay in the temperature sensor 6, so the air temperature T continues to rise until the point b where the control circuit 9 is activated. Then, at point b, the control circuit 9 is activated, the clutch 7 is reconnected, the compressor 1 begins to move, and the above operation is repeated thereafter.

Therefore, since the above operation is repeated, (1) When the compressor is in operation, the compressor 1 has excess capacity compared to the cooling capacity, but when the compressor is stopped, the overheating region increases due to the lack of liquid refrigerant inside the evaporator 5. As a result, the refrigerant capacity decreases, resulting in wasted effort as a whole.

(2) Due to the intermittent operation of the compressor 1, the temperature of the air blown from the evaporator fluctuates significantly, which worsens the feeling of cooling.

(3) When the clutch 7 is disengaged, the difference in torque acting on the friction surface of the clutch is large, which adversely affects the durability of the clutch.

(4) When the clutch 7 is disengaged, a relatively large torque is applied to the engine, which causes a shock, etc., which deteriorates the running feeling.

This causes various problems such as:

Therefore, in place of the above-mentioned control using the clutch 7 on and off, a method has been proposed in which the discharge capacity of the compressor 1 is controlled (Japanese Patent Laid-Open No. 107042/1983). By using this compressor capacity control, the number of times the electromagnetic clutch 7 is engaged can be significantly reduced, and many of the above-mentioned problems can be solved.

However, in an automobile refrigeration cycle control device using conventional compressor discharge capacity control, the capacity of the compressor 1 is simply varied in place of and in addition to the engagement and engagement of the electromagnetic clutch 7, and the variable capacity The control of automobile refrigeration cycles equipped with compressors has not yet been achieved sufficiently.

In other words, if the cooling capacity is insufficient or surplus, the evaporator 5
This is not only reflected in the air temperature immediately after, but also changes depending on the state of each element that affects the cooling capacity, such as the engine speed, vehicle speed, and amount of solar radiation. Furthermore, even if the temperature of the air blown immediately after the evaporator 5 is constant, depending on the condition of the occupants, they may feel that the cooling capacity is excessive. Therefore, in an automobile refrigeration cycle equipped with a compressor whose discharge capacity can be variably controlled, it is desirable to use the discharge capacity control of the compressor in a manner that most effectively adapts to each of these conditions.

[Problem to be solved by the invention]

The present invention was devised in view of the above points, and
Automotive refrigeration cycle control using compressor discharge capacity control is not limited to simply controlling the evaporator temperature, but is also based on the state of factors that affect cooling performance, such as engine speed, vehicle speed, and amount of solar radiation, or the will of the occupants. The purpose is to be able to control even when

〔composition〕

In order to achieve the above object, the automotive refrigeration cycle control device of the present invention includes a sensing means that senses the temperature related to the degree of cooling of the evaporator or the refrigerant pressure, as well as manual operation and elements that affect the cooling capacity. A small capacity setting means is provided which outputs a signal indicating a state in which there is a surplus in cooling capacity by detecting at least one of the states. Based on the input signals from the sensing means and the small capacity setting means, the control means operates the drive device to control the displacement of the compressor.

In the control device of the present invention, the control means basically controls the discharge capacity of the compressor by operating the drive device according to the input signal from the sensing means, and the small capacity setting means When an input signal is received from the sensor, the compressor is controlled to a smaller capacity regardless of the compressor discharge capacity setting based on the input signal from the sensing means.

[Operation]

By employing the above configuration, the control device of the present invention controls the discharge capacity of the compressor during normal cooling operation based on the signal from the sensing means that senses the temperature or refrigerant pressure related to the degree of cooling of the evaporator. As a result, the cooling capacity of the refrigeration cycle can be controlled so that the temperature of the air blown from the evaporator remains approximately constant. As a result, the number of times the electromagnetic clutch is engaged can be significantly reduced, and the evaporator outlet air temperature can be largely varied and the shock of the clutch interrupter can be rotated.

Furthermore, when the occupant feels that there is excess cooling capacity, or when a surplus cooling capacity is detected based on signals from engine speed, vehicle speed, solar radiation, etc., the Then, the control means operates the drive device so as to control the discharge capacity of the compressor to a smaller capacity side.

〔Effect of the invention〕

Therefore, with the control device of the present invention, surplus cooling capacity can be detected more accurately and precisely, and the consumption capacity of the compressor can be reduced as a whole. Along with this, it is possible to make the most effective use of the compressor's small-capacity operation characteristics, reduce the engine load as much as possible, and effectively transmit the output generated by the engine to the traveling side, improving fuel efficiency and driving characteristics. can be improved.

〔Example〕

The present invention will be described below with reference to embodiments shown in the drawings. Since the refrigeration cycle in the apparatus of the present invention may be the same as that shown in FIG. 1, the explanation will be omitted. FIG. 4 schematically shows the entire control system of the device of the present invention. Reference numeral 11 is a resin ventilation casing of an automotive air conditioner, and inside it is the evaporator 5 shown in FIG. 1 and a motor-driven blower. 8 is provided. The left end side of the ventilation casing 11 communicates with an inside air intake port and an outside air intake port via an outside/outside air switching box (not shown), and the right end side communicates with an air outlet (upper air outlet for cooling) into the vehicle interior via a heater unit (not shown). (lower air outlet for heating, etc.). A compressor 12 is connected to the outlet side refrigerant circuit of the evaporator 5,
This compressor 12 is driven by an automobile engine via an electromagnetic clutch 13. Further, the compressor 12 is constructed as a variable displacement type which incorporates a variable capacity member 18 for varying the discharge capacity, as will be described later. 14 is a temperature sensor consisting of a thermistor for sensing the temperature of the air immediately after the evaporator; 15 is a control circuit to which the signal of this temperature sensor 14 is input for driving the variable capacity member 18 in the compressor 12; The solenoid valve is controlled by the output of the control circuit 15. Reference numeral 20 denotes a relay for intermittent operation of the compressor 12, and is used for intermittent energization of the electromagnetic clutch 13. 21 is an operation switch for the air conditioner; 2
2 is an ignition switch, and 23 is an in-vehicle power battery.

FIG. 5 shows a specific example of the control circuit 15, in which the comparator 34 has a potential V ₁ determined by the resistor 24 and the thermistor resistance value R ₁₄ of the outlet temperature sensor 14 of the evaporator 5, and the resistor 25, The comparator output 34a is determined by the reference potential _V2 determined by the resistance values of the resistors 26 and 31. The transistors 38 and 39 are turned on and off by the comparator output 34a, thereby controlling the operation of the relay 20. Then, the electromagnetic clutch 13 is energized or disconnected by opening or closing the contact 20a of the relay 20.

The comparator 35 has a potential V ₁ determined by the resistor 24 and the thermistor resistance value R ₁₄ of the outlet temperature sensor 14 of the evaporator 5, and a reference potential V ₃ determined by the resistance values of the resistors 27, 28, and 32. Comparator output 35a is determined. transistor 4
0 and 41 are turned on and off by the comparator output 35a, thereby controlling the operation of the relay 37. Then, the energization of the solenoid valve 16 is interrupted by opening and closing the contact 37a of the relay 37. A manually operated switch 42 is provided between the base of the transistor 40 and ground, and by closing its contact 42a, the solenoid valve 16 is closed regardless of the comparator output 35a.
can be energized. Note that the transistor 40
A small capacity setting means a for inputting a signal from the engine speed is connected to the base of the motor.

The temperature sensor 14 is a thermistor with a negative characteristic whose resistance value decreases as the temperature rises, and the reference potentials V ₂ and V ₃ of the comparators 34 and 35 are set to have a relationship of V ₂ >V ₃ , so that R ₁₄ Depending on the value of , the comparator outputs 34a and 35a have a relationship as shown in FIG. 6, respectively.

Now, if the temperature of the blowing air immediately after the evaporator 5 is high,
The resistance of R ₁₄ is less than R _14A . Therefore, the comparator outputs 34a and 35a are each "Hi"
level, the relay 20 is turned on and the relay 37 is turned off. Therefore, the electromagnetic clutch 13 is turned on, the electromagnetic valve 16 is turned off, and the compressor 12 is operated at full capacity with 100% discharge capacity.

On the other hand, the blowing air temperature decreases and the resistance value of _R14 decreases.
When it becomes larger than R _14B , the comparator output 35a becomes the "L ₀ " level, the relay 37 is turned on, the solenoid valve 17 is energized, and the valve is opened, so that the compressor 12 is operated at a small capacity (30 to 50%). will be done.

The blowout temperature further decreases, and the resistance value of R ₁₄ decreases to R _14D.
When the voltage is below, the comparator output 34a becomes the "L ₀ " level, the relay 20 is turned off, and as a result, the electromagnetic clutch 13 is also turned off and the compressor 12 is stopped.

Next, an example of a specific configuration of the compressor 12 will be described. In Fig. 7, 100 is a cylindrical rotor,
Reference numeral 101 denotes vanes slidably inserted in the radial direction into slits 102 provided in the rotor 100. Although only two vanes are shown in FIG. 8, there are actually four vanes provided at equal intervals. 103 is this vane 10
The cylindrical cylinders 104 and 105 that regulate the radial reciprocating motion of the rotor 100 and the vane 101 are a front side plate and a rear side plate that sandwich both ends of the cylinder 103 through a small gap. And these rotors 100,
A working space V is formed by the vane 101, the cylinder 103, the front side plate 104, and the rear side plate 105. In addition, the cylinder 103,
The front side plate 104 and the rear side plate 105 are tightened and fixed together with the housings 106 and 107 with bolts 108. Furthermore, rotor 10
0 is integrally connected to a rotating shaft 109, which is rotatably supported by a front side plate 104 and a rear side plate 105 by a bearing 110, and receives driving force from an automobile engine via an electromagnetic clutch 13 and the like. I'm starting to accept it. 111 is a shaft sealing device that maintains a seal with the outside air.

A suction chamber 112 is formed by the front side plate 104 and the housing 106, and the suction chamber 112 is
The refrigerant sucked into the refrigerant 2 is sucked into the working space V through a suction port 113 (FIG. 9) opened in the front side plate 104. That is, the working space V is filled with refrigerant at suction pressure (as shown in FIG. 9a). The refrigerant sucked into the working space V is compressed as the volume of the working space V decreases, and in the most compressed state, the cylinder 10
The liquid is discharged from the discharge port 114 of No. 3 into the discharge chamber 107a in the housing 107 via a discharge valve (not shown), and then discharged to the condenser 2 of the refrigeration cycle.

P is an unloading port that opens in the front side plate 104 and connects the working space V and the suction chamber 112.
It communicates with Therefore, when the unloading port P is open, the refrigerant will not be compressed until the working space V leaves the communication state with the unloading port P.
The space volume V ₁ at the start of compression with the unloading port P open is shown in FIG. 9b, and the space volume V ₀ at the start of compression with the unloading port P closed is shown in FIG. Shown in a. In this example, the unloading port P is opened at a position where _V1 is about 30% to 50% of _V0 .

115 is an on-off valve that opens and closes the unloading port P. To explain the structure of this on-off valve 115 in detail, as shown in FIG. A bellows flamm 115c to be driven, and a plate 115f that also serves as a spring seat and guides the bellows flamm 115c.
It is equipped with The valve body 115a is made of a high-strength material such as stainless steel. A pilot pressure introduction passage 117 communicates with a chamber 115d on the back side of the bellow flamm 115c, and pilot pressure, that is, suction pressure or discharge pressure, is applied under control of the electromagnetic valve 16.
Reference numeral 117a denotes a restriction formed in the pilot pressure introduction passage 117, which allows the pilot pressure to suddenly flow into the chamber 11.
This prevents the voltage from being applied to 5d. On the other hand, the pressure of the suction chamber 112 is applied to the chamber 115e on the side facing the bellow frame 115c.

The combination of the port P and the on-off valve 115 described above constitutes the variable capacity member 18.

The drive of the on-off valve 115 of the port P is controlled by the solenoid valve 16.

As shown in FIG. 10, the electromagnetic valve 16 is provided with three pressure ports: a suction pressure inlet 16a, a discharge pressure inlet 16b, and a pilot pressure outlet 16c.
12 pressure, the discharge pressure inlet 16b is connected to the discharge chamber 1.
07a, and the pilot pressure outlet 16c is connected to the on-off valve 1.
15, the chamber on the closed side of the valve body, that is, the pilot chamber 115d
is familiar with The position of a valve body 16e made of a magnetic material is controlled by energizing the coil 16d on and off, so that suction pressure or discharge pressure is selectively applied to the pilot pressure outlet 16c of the solenoid valve 16. It's summery.

Therefore, when suction pressure is introduced into the pilot pressure outlet 16c, the pilot chamber 115d becomes suction pressure, so the valve body 115a moves in the opening direction by the setting force of the spring 115b, and the on-off valve 115 closes the port P. . Conversely, when the discharge pressure is introduced into the pilot pressure outlet 16c, the pilot chamber 115d also reaches the discharge pressure, so the valve body 115a moves in the closing direction against the setting force of the spring 115b, and the opening/closing valve is closed. 115 blocks port P.

In order to prevent malfunction due to overheating, the solenoid valve 16 is placed in contact with a relatively low-temperature portion of the compressor 12, such as a service valve (not shown) through which suction refrigerant passes, and the front housing 106. has been done.

Next, the operation of the control method according to this embodiment will be explained. Now, the temperature of the blowing air immediately after the evaporator 5 is high, and the thermistor resistance value R14 of the temperature sensor ₁₄ is
When R is smaller than _14A , the comparator output 35a becomes "Hi" level. As a result, transistor 4
0 is turned on, the base and emitter of transistor 41 become almost at the same potential, and are cut off, relay 3
The normally open contact 37a of No. 7 is opened and the solenoid valve 16 is not energized. Therefore, the solenoid valve 16 is in the state shown in FIG. 10, and since the valve body 16e opens the discharge pressure inlet 16b, the valve body 115a of the on-off valve 115 is pressed by the discharge pressure and closes the port P. There is.
This increases the discharge capacity of the compressor 12 to a large capacity (100
% capacity) and perform full operation.

Then, when the temperature of the air blown from the evaporator 5 decreases and the thermistor resistance value _R14 of the temperature sensor 14 becomes equal to or lower than _R14B , the comparator output 35a becomes the " _L0 " level, thereby turning off the transistor 40. As a result, an appropriate base bias is applied to the transistor 41 to turn it on, the normally open contact 37a of the relay 37 is closed, and the solenoid valve 16 is energized.
Therefore, the valve body 16e of the solenoid valve 16 is connected to the coil 16d.
The spring 115 closes the discharge pressure introduction port 16b and opens the suction pressure introduction port 16a.
b to open the port P. As a result, the discharge capacity of the compressor 12 is small (30 to 50%
capacity).

When the blowing temperature further decreases and the thermistor resistance value R ₁₄ of the temperature sensor 14 becomes equal to or lower than R _14D , the comparator output 34a becomes the "L ₀ " level. This turns off transistor 38 and cuts off the base bias of transistor 39. Therefore, the normally open contact 20a of the relay 20 is in an open state, and the electromagnetic clutch 13 is disconnected and the compressor 12 is disconnected.
operation will be stopped. This prevents overcooling of the indoor air and frosting of the evaporator 5.

Also, the transistor 4 after the comparator 35
0 base and the ground of the main control circuit 15, 42
The manually operated normally open switches 42a and 42b allow the compressor 12 to be switched to small capacity operation even during high capacity operation, regardless of the comparator output 35a. That is, normally open contact 42a
By closing the transistor 40, the transistor 40 is turned off,
A suitable base bias is applied to the transistor 41 to turn it on, the normally open contact 37a of the relay 37 is closed, and the solenoid valve 16 is energized. Therefore normally open contact 4
2a is closed by the user, the refrigeration cycle operates at a small capacity when the comparator output 34a is at the "Hi" level, and at the pressure type when the comparator output 34a is at the "L ₀ " level, regardless of the comparator output 35a. When the operation of the machine 12 is stopped and the normally open contact 42a is opened, the refrigeration cycle control function described above is restored.

As described above, in this example, the air temperature immediately after the evaporator is sensed, and the compressor capacity is switched and controlled according to the sensing signal, so that the refrigeration cycle can be operated at the optimal capacity according to the load at that time. It has the great effect of reducing the power consumption of the compressor, and also has good control characteristics without causing problems such as reduced durability due to intermittent use of the compressor or worsening of the cooling sensation due to fluctuations in air sound. At the same time, it is possible to perform intermittent operation at a small capacity depending on the user's will or other conditions, and when it is desired to prioritize power saving over cooling (for example, when accelerating or climbing), the engine can be It is extremely effective in reducing load, and can improve fuel efficiency and driving characteristics.

FIG. 11 shows another example of the small capacity setting means of the control circuit 15 shown in FIG. 5, which inputs a signal from the engine speed. In this example, the input terminal 45 is connected to the ground side of a primary coil 44a of an ignition coil 44 of an engine (not shown), and a rectangular wave voltage having a frequency corresponding to the engine speed is applied thereto. 43a is a frequency-voltage conversion circuit, and the voltage across the capacitor 46 (potential at point B) increases as the engine speed increases. 47 is a comparator, and when the engine speed is below a predetermined speed (for example, 2000 r.p.m.), the comparator output becomes a "Hi" level, and when it is above a predetermined speed, it becomes a "L ₀ " level.

In this example, the engine speed is 2000 r.
When it is equal to or higher than p.m, the comparator output 47a becomes "L ₀ " level, the transistor 48 is turned off, and the transistor 49 is turned on. Therefore, a signal from the engine is input to input terminal a (FIG. 5). As a result, transistor 4 in FIG.
0 is off and transistor 41 is on. Therefore, the relay 87 is energized and the normally open contact 37a is closed.
The solenoid valve 16 is activated, and the discharge capacity of the compressor 12 is set to a small capacity. The operating state of the refrigeration cycle in this case is the same as that in which the normally open contact 42a of the manually operated switch 42 is closed as shown in FIG.

When the engine speed is less than 2000 rpm, the comparator output 47a becomes "Hi" level, the transistor 48 is turned on, and the transistor 49 is turned off. Therefore, the signal from the engine is input terminal a
(Figure 5) is not input. As described above, the compressor 12 is controlled to switch from large capacity to small capacity and its operation is interrupted in accordance with each level of the comparator outputs 34a and 35a.

12 to 15 are electric circuits showing other examples of the small capacity setting means of the control circuit 15 shown in FIG. 5.

In FIG. 12, a transistor 51 is turned on and off in conjunction with a switch 50 related to an element that affects the cooling capacity, and when the switch 50 is turned on, the transistor 51 is turned on, and the signal from the switch 50 is
It is input to the input terminal a shown in the figure, and switches the compressor 12 and discharge capacity to a small capacity. Examples of such switches include a wiper start switch, a defroster input switch, a light lighting switch, a small light lighting switch, and a small air volume changeover switch for a blower. Two or more of these switches may be linked. All of these switches indirectly indicate that there is less heat transfer from outside the vehicle due to decreased solar radiation, or that the interior of the vehicle is relatively cool, so they do not require much cooling capacity. This corresponds to the case where no

In FIG. 13, the output of the wheel rotation detection amplifier 52 that detects the vehicle speed is input to the transistor 53, and when the rotation speed of the wheel increases above a certain level, the transistor 58 is turned on, and a signal is input to the input terminal a in FIG. This is to set the discharge amount of the compressor 12 to a small capacity. The vehicle speed is an indirect measure of the engine rotational speed, and takes into account that the cooling capacity is often excessive when the speed is above a certain level.

FIG. 14 shows a system in which the amount of solar radiation is directly detected by a photodiode 54, and when the amount of solar radiation becomes less than a set value, a transistor 55 is turned on and an input signal is applied to terminal a in FIG. 5 to switch the discharge amount of the compressor 12 to a small capacity. It is. The idea is that if the amount of solar radiation decreases, the cooling load will become smaller and the cooling capacity will also be reduced.

As mentioned above, in this example, the air temperature immediately after the evaporator is sensed, and the compressor capacity is switched and controlled according to the sensing signal, so that the refrigeration cycle can be operated at the optimum capacity according to the load at that time. , detects the state of elements that affect cooling capacity, such as engine speed, and automatically controls the compressor capacity to a small capacity, so that the refrigeration cycle operates at a capacity that corresponds to the load at that time, and the compression This reduces the power consumption of the machine, reduces the number of times the compressor is turned on and off, eliminates fluctuations in air temperature, and improves the feeling of cooling.

In the above-mentioned embodiment, the air temperature immediately after the evaporator is sensed and controlled, but it is also possible to control the refrigerant pressure inside the evaporator, the dynamic refrigerant temperature, or the surface temperature of the evaporator fin or refrigerant piping. This may be sensed and used as a control signal for capacity control.

In addition, if the resistor 24 etc. is made into a variable resistor that can be manually adjusted from the outside so that the user can freely adjust the set temperature of the room temperature, the present invention can be used for the purpose of controlling the room temperature in addition to preventing frosting of the evaporator. can be applied.

Similarly, although the compressor capacity is controlled in two stages in this embodiment, it goes without saying that the compressor capacity may be controlled in three stages or continuously for more detailed control.

In addition, the compressor 12 is not limited to the vane type.
Other types such as swash plate types can also be used.

[Brief explanation of drawings]

Fig. 1 is a refrigeration cycle diagram of a conventionally well-known automobile air conditioner, Fig. 2 is an electric circuit diagram showing the capacity control circuit of the device shown in Fig. 1, and Fig. 3 is a refrigerant in an evaporator using a conventionally well-known capacity control method. A characteristic diagram showing changes in pressure and air temperature immediately after the evaporator, Fig. 4 is a block diagram showing the overall control system of the device of the present invention, and Fig. 5 is an electric circuit showing the specific configuration of the control circuit 15 of the device of the present invention. Figure 6 shows the comparators 34, 3 shown in Figure 5.
5, FIG. 7 is a sectional view showing an embodiment of the compressor used in the present invention, FIG. 8 is a sectional view showing the configuration of the compressor internal capacity variable member, and FIGS. 9a and 9b are
An explanatory diagram showing a variable capacity mechanism of a compressor used in the present invention, FIG. 10 is a sectional view of a solenoid valve used in an embodiment of the present invention, and FIGS. 11 to 14 are a control circuit 15.
FIG. 3 is a circuit diagram of a small capacity setting means added to the circuit. 5... Evaporator, 12... Compressor, 13... Electromagnetic clutch, 14... Temperature sensor, 15... Control circuit, 17... Solenoid valve forming a drive device, 18... Variable capacity member.

Claims (1)

[Scope of Claims] 1. A compressor that sucks in, compresses, and discharges refrigerant in response to the driving force of an automobile engine, and an electromagnetic clutch that switches between transmitting and non-transmitting the driving force from the engine to the compressor. , a variable capacity member for changing the discharge capacity of the compressor, a drive device for driving the variable capacity member, a sensing means for sensing temperature or refrigerant pressure related to the degree of cooling of the evaporator, manual operation and cooling capacity. a small capacity setting means for outputting a signal indicating a state in which there is a surplus in cooling capacity by sensing at least one of the states of elements that affect the cooling capacity; control means for operating a drive device to control the discharge capacity of the compressor, the control means operating the drive device in response to an input signal from the sensing means to control the discharge capacity of the compressor. and, by the input signal from the small capacity setting means, the drive device is operated to the small capacity side, regardless of the discharge capacity setting of the compressor by the input signal from the sensing means, and the discharge of the compressor is adjusted. An automotive refrigeration cycle control device characterized by changing the capacity to a smaller capacity. 2 The control means controls the compressor discharge capacity in two stages of 20% to 50% and 100% according to the input signal from the sensing means, and also connects and disconnects the electromagnetic clutch according to the input signal, and The control device according to claim 1, wherein the control device is configured to control the discharge capacity of the compressor to 20% to 50% by input from a capacity setting means, regardless of the input signal. . 3. The control device according to claim 1 or 2, wherein the small capacity setting means comprises engine speed detection means that generates a signal when the engine speed rises above a set value. 4. The control device according to claim 1 or 2, wherein the small capacity setting means comprises vehicle speed detection means that generates a signal when the vehicle speed rises above a set value. 5. The control device according to claim 1 or 2, wherein the small capacity setting means comprises solar radiation detection means that generates a signal when the solar radiation falls below a determined value. 6. The above-mentioned small volume setting means is a patent comprising a setting means that generates a signal in conjunction with one or more of the following switches: a wiper start switch, a defroster input switch, a light lighting switch, a small light lighting switch, and a blower small air volume selection switch. A control device according to claim 1 or 2.