JPH0332488B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an air conditioner for an automobile, and more particularly to an air conditioner for an automobile in which the discharge capacity of a compressor can be variably controlled.

[Conventional technology]

As shown in Fig. 1, the refrigeration cycle of a conventional automobile air conditioner includes a compressor 1 driven by an automobile engine, a condenser 2 that condenses refrigerant discharged from the compressor 1, and this condenser. A receiver 3 stores the liquid refrigerant condensed in step 2, an expansion valve 4 into which the liquid refrigerant is introduced from the receiver and performs depressurization and expansion of the liquid refrigerant, and a receiver 3 that exchanges heat with uncooled air to remove vaporization heat from the air and cool the air. evaporator 5. Here, the compressor 1 is connected to an automobile engine (not shown) via an electromagnetic clutch 7.
Therefore, as the engine speed increases, the compressor speed increases.
Therefore, when the rotational speed of the compressor increases and the cooling capacity increases, or when the cooling 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, decreases to 0°C. There is a risk of frost forming on the fins or freezing.
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 other frosting phenomena 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 control circuit 9 shown in FIG. By opening and closing the tangent 10a of the relay 10, the electromagnetic clutch of the compressor is connected and disconnected. This makes it possible to adjust the operating time of the compressor 1, control the evaporation temperature of the refrigerant, and control the air temperature immediately after the evaporator.

By the way, in such a configuration, if the cooling load decreases or the cooling capacity increases due to an increase in the rotation speed of the compressor, the capacity of the refrigeration cycle will exceed the cooling load, and as shown in Figure 3, the evaporation will increase. The air temperature T immediately after the device 5 decreases, and the contact temperature decreases at point C.
T becomes less than ₀ . However, due to its heat capacity, the temperature sensor 6 has a time delay as shown in FIG. 3 until the control circuit 9 is activated.
The air temperature T further decreases during the period from point A to point a where the control circuit operates (that is, the time), and the set temperature
It will be much lower than T ₀ . Then, at point a, the control circuit 9 operates, and when the clutch 7 is disengaged, 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 pressure _P1 inside the evaporator 5 increases,
The superheat range of the refrigerant increases. As a result, the effective heat transfer area of the evaporator 5 decreases, and the air temperature immediately after the evaporator 5 T
will rise rapidly. As a result, the temperature at point d becomes equal to or higher than the set temperature T ₀ . However, due to the same reason as above, there is a time delay in the temperature sensor 6.
Therefore, the air temperature T continues to rise until the point b where the control circuit 9 is activated. At point b, the control circuit 9 is activated, the clutch 7 is reconnected, the compressor 1 begins to operate, and the above operation is repeated thereafter.

However, in this conventional system, the compressor 1 is always operated intermittently at maximum capacity regardless of fluctuations in the cooling load due to changes in outside temperature, etc., so the drive load of the drive source of the compressor 1 is always kept at the maximum. As the power consumption of the engine increases, the noise also increases.

Therefore, a conventional method has been proposed in which the air temperature T immediately after the evaporator 5 is detected by a temperature sensor 6, and the capacity of the compressor is variably controlled based on the signal (Japanese Patent Laid-Open No. 53
−107042). In this conventional compressor, the compressor is not always operated at maximum capacity, but the capacity is varied as appropriate, and can solve the above-mentioned problem of increased power consumption.

However, this conventional system merely controls the compressor capacity instead of controlling the compressor operation according to the intermittent engagement of the clutch. However, no consideration was given to using the compressor control more efficiently.

In view of preventing frost on the evaporator 5,
Although the cooling capacity is basically controlled by the air temperature immediately after the evaporator 5, there are other conditions that affect the cooling capacity or the cooling load.

For example, the ambient temperature of a car has a large effect on the cooling load. Particularly in the case of air conditioners for automobiles, the ambient temperature of the automobile often changes rapidly as the automobile moves, for example, when the automobile is driven in a tunnel or under conditions exposed to sunlight. If the ambient temperature changes in this way, the condensing capacity of the condenser 2 and the cooling load of the passenger compartment will change.

Therefore, in an automobile air conditioner that can change the discharge capacity of the compressor, the capacity of the compressor is not simply controlled based on the air temperature immediately after the evaporator 5, but also according to the ambient temperature of the automobile. If the air conditioner can be controlled even when the air conditioner is in use, the overall control of the automobile air conditioner will be more fine-grained, which will lead to a further reduction in power consumption.

In addition, in an automobile air conditioner, the number of revolutions of the engine has a direct influence on the cooling capacity. As mentioned above, since the compressor 1 is operated by receiving the driving force from the engine for driving the vehicle, the discharge capacity of the compressor directly responds to the rotational speed of the engine. Changes in compressor discharge capacity due to changes in engine speed will eventually lead to changes in cooling capacity and changes in air temperature at the evaporator outlet, but this will be affected by the time delay mentioned above. . In other words,
This means that changes in the cooling capacity of the automobile air conditioner cannot be accurately detected based only on the air temperature immediately after the evaporator 5.

[Problem to be solved by the invention]

The present invention has been made in view of the above-mentioned points, and in an automotive air conditioner that can variably control the discharge capacity of a compressor, a signal for changing the capacity of the compressor and a signal for switching between compressor operation and non-operation are transmitted immediately after the evaporator. It is an object of the present invention to enable control based not only on the air temperature but also on two or more sensing signals, thereby reducing the power consumption of the compressor as a whole.

〔composition〕

In order to achieve the above object, a first aspect of the present invention includes a compressor that receives driving force from an automobile engine and sucks, compresses, and discharges refrigerant; and a compressor that receives driving force from an automobile engine and transmits the driving force to the compressor. - An electromagnetic clutch that switches to non-transmission, a variable capacity member that changes the discharge capacity of the compressor, a drive means that drives the variable capacity member, and a first element that senses the temperature or refrigerant pressure related to the degree of cooling of the evaporator. a sensing means; a second sensing means for sensing the ambient temperature of the vehicle; and control means for controlling the clutch to switch between operating and non-operating the compressor, the control means controlling at least one of the driving means and the electromagnetic clutch based on the sensing signal from the first sensing means to switch the compressor into operation. control the capacity and activation/deactivation of the evaporator to prevent frosting of the evaporator, and when the ambient temperature of the vehicle is higher than a predetermined temperature based on the sensing signal from the second sensing means, at least one of the driving means and the electromagnetic clutch is activated. controls the compressor between large capacity and non-operation, and controls at least one of the driving means and the electromagnetic clutch to switch the compressor from small capacity to non-operation when the ambient temperature of the automobile is below a predetermined temperature. A configuration is adopted in which control is performed between operations.

Further, in the second aspect of the present invention, in addition to the first sensing means for sensing the temperature or refrigerant pressure related to the degree of cooling of the evaporator and the second sensing means for sensing the ambient temperature of the automobile, The control means controls the driving means and the electromagnetic clutch according to the sensing signals from the first sensing means, the second sensing means, and the third sensing means to operate and control the compressor. Variable control of deactivation and capacity.

That is, in the second aspect of the present invention, the control means controls at least one of the drive means and the electromagnetic clutch based on the sensing signal from the first sensing means to control the capacity and operation/non-operation of the compressor, The evaporator is prevented from frosting, and based on the signal from the second sensing means, when the ambient temperature of the automobile is higher than a predetermined temperature, at least one of the driving means and the electromagnetic clutch is controlled to switch the compressor from a large capacity to a non-operating state. and controlling at least one of the drive means and the electromagnetic clutch when the ambient temperature of the vehicle is below a predetermined temperature to control the compressor between small capacity and non-operation; Based on the sensing signal from the means, when the engine speed is above a predetermined number, the drive means is controlled to prevent the compressor speed from increasing to a large capacity.

[Operation]

By employing the above configuration, the automotive air conditioner of the first aspect of the present invention switches the capacity of the compressor or switches the compressor between operation and non-operation based on the signal from the first sensing means. This effectively prevents frost from forming or freezing on the evaporator. Furthermore, based on the signal from the second sensing means, the condensing capacity of the condenser, the cooling load in the vehicle interior, etc. are sensed from the ambient temperature of the vehicle,
As a result, the discharge capacity of the compressor is not increased in a state in which the cooling capacity is likely to exceed the cooling load, that is, in a state in which the ambient temperature of the vehicle is below a predetermined value. In this state, the capacity of the compressor is controlled between a state where the discharge capacity is small and a state where the discharge capacity is 0, in other words, a state where the compressor is not in operation.

On the other hand, in a state where the cooling capacity is assumed to be lower than the cooling load, that is, when the ambient temperature of the automobile is above a predetermined value, the capacity of the compressor may be reduced depending on the signal condition from the first sensing means. Can be increased to maximum capacity. In this state, depending on the air temperature immediately after the evaporator, the capacity of the compressor can be set to maximum capacity, small capacity, or even zero capacity (compressor stopped) to effectively prevent frosting of the evaporator. We will aim to do so.

Further, in the automobile air conditioner according to the second aspect of the present invention, in addition to the above-mentioned signals, the rotation speed of the engine can also be detected from the third detection means. This results in
In a state where the engine rotational speed is high, the compressor rotational speed is also high, and the compressor discharge amount is increasing, the discharge capacity of the compressor can be controlled so as not to become large.

Therefore, in the automobile air conditioner according to the second aspect of the present invention, when the ambient temperature of the automobile is high and the temperature of the evaporator is also high, the discharge capacity of the compressor is set to the maximum capacity to increase the cooling capacity. Even if the engine speed is above a predetermined value, the discharge capacity of the compressor is controlled so as not to increase to a large capacity.
In general, in automobile air conditioners, the discharge capacity of the compressor is set so that sufficient cooling capacity can be achieved even when the engine speed is low, so when the engine speed is higher than a predetermined value, Even if the discharge capacity of the compressor is not increased to a large capacity, a sufficient amount of refrigerant circulating through the refrigeration cycle as a whole can be ensured, and there will be no shortage of cooling capacity.

〔Effect of the invention〕

As described above, the automotive air conditioner of the present invention senses not only the temperature of the evaporator but also other conditions related to the cooling capacity and cooling load, and also determines the capacity of the compressor based on this sensing signal. Since the compressor can be variably controlled, it has the effect of significantly reducing the power consumption and noise of the compressor.

〔Example〕

Embodiments of the first invention shown in the drawings will be described below.

The refrigeration cycle in the method of the present invention may be the same as that shown in FIG. 1, so its explanation will be omitted. FIG. 4a schematically shows the entire control system of the method of the present invention. Reference numeral 11 is a resin ventilation casing of an automobile air conditioner, and inside it is the evaporator 5 shown in FIG. A 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 air temperature immediately after the evaporator; 19 is a temperature sensor consisting of a thermistor for sensing the representative temperature around the vehicle, for example, the temperature of the cooling air in front of the pseudo-condenser 2 The sensor 15 is the temperature sensor 14, 19.
A control circuit 16 receives the signal from the control circuit 16, which is a solenoid valve for driving the variable capacity member 18 in the compressor 12, and is controlled by the output of the control circuit 15.
21 is an operating switch for the air conditioner, 22 is an ignition switch, and 23 is an on-vehicle power battery.

FIGS. 4b and 4c show an example of the mounting position of a temperature sensor 19 consisting of a thermistor for sensing the ambient temperature of the vehicle. 60 is an in-vehicle engine, 61 is an in-vehicle air conditioning unit, and 63 is a fender mirror.

FIG. 5 shows a specific example of the control circuit 15, in which 31 is a comparator, and the potential V ₁ determined by the resistance value of the resistor 32 and the thermistor resistance value R ₁₄ of the temperature sensor 14, and the resistor 33, The output 31a is determined by the reference potential V ₂ determined by the resistance value of 34. 35 is this comparator output 31a
energization of the electromagnetic clutch 13 is interrupted by a relay controlled by the relay.

A comparator 36 outputs an output 36a based on a potential V ₃ determined by the resistance value of the resistor 37 and the thermistor resistance value R ₁₉ of the temperature sensor 19, and a reference potential V ₄ determined by the resistance values of the resistors 38 and 39. is determined. 40 is a relay controlled by this comparator output 36a, which turns the electromagnetic valve 16 on and off.

Both temperature sensors 14 and 19 are negative characteristic thermistors whose resistance value decreases as the temperature rises, and the relationship between the changes in the thermistor resistance values R ₁₄ and R ₁₉ and the comparator outputs 31a and 36a is shown in FIG. b
The settings are as shown below.

As shown in FIG. 6a, the comparator output 31a
When the temperature of the blowing air immediately after the evaporator rises above, for example, 4℃ and R ₁₄ decreases from R _14A , the level becomes “Hi”; conversely, when the temperature of the blowing air immediately after the evaporator falls below, for example, 3℃, R ₁₄ becomes R _14B. When it increases further, it becomes "Lo" level.

As shown in FIG. 6b, the comparator output 36a
When the ambient temperature of the vehicle rises above the set temperature, e.g. 26°C, and R ₁₉ decreases below R _19A , the level becomes “Hi”;
When _R19 becomes lower than _R19B , it becomes "Lo" level.

Next, an example of a specific configuration of the compressor 12 will be described. In FIG. 7, 100 is a cylindrical rotor, and 101 is a slit 10 provided in the rotor 100.
Although only two vanes are shown in FIG. 9, there are actually four vanes inserted at equal intervals in the radial direction. 103 is a cylindrical cylinder that restricts the reciprocating movement of the vane 101 in the radial direction; 104 and 105 are the rotor 100;
and the cylinder 1 through the vane 101 and a small gap.
These are the front side plate and rear side plate that narrow both ends of 03. The rotor 100, vane 101, cylinder 103, front side plate 104, and rear side plate 105 form an operating space V. Furthermore, the cylinder 103, front side plate 104, and rear side plate 105 are connected to housings 106, 107.
At the same time, they are tightened and fixed with bolts 108. The rotor 100 is integrally connected to a rotating shaft 109, and the rotating shaft 109 is connected to the front side plate 104 and the rear side plate 1 by bearings 110.
05, and receives driving force from an automobile engine via an electromagnetic clutch 13 and the like. 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 according to the present invention, which opens in the front side plate 104 and communicates the working space V and the suction chamber 112. Therefore, when this 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, and this unloading port The space volume V ₁ at the start of compression with the loading port P open is shown in Figure 9b, and the space volume V ₀ at the start of compression with the unloading port P closed is shown in Figure 9a.
Shown below. 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 surface side of 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
It is familiar to 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 opens 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 of the present invention will be explained. If the ambient temperature of the vehicle is currently higher than 26°C and the thermistor resistance value _R19 of the temperature sensor 19 is smaller than _R19A , the comparator output 36a becomes "Hi" level, the normally closed contact 40a of the relay 40 is opened, and the electromagnetic Valve 16 is not energized. Therefore, the solenoid valve 16 is in the state shown in FIG. 10, and the valve body 16e opens the discharge pressure inlet 16b, so the valve body 115a of the on-off valve 115 is pressed by the discharge pressure and closes the port P. ing. Thereby, the discharge capacity of the compressor 12 is set to a large capacity (100% capacity).

Under the above conditions, the evaporator discharge air temperature is 4℃
If higher, the thermistor resistance value of the temperature sensor 14
R ₁₄ becomes smaller than R _14A , comparator output 3
1a becomes the "Hi" level, the normally open contact 35a of the relay 35 is closed, and the electromagnetic clutch 13 is connected. Therefore, the compressor 12 operates at full capacity with a large discharge capacity.

Then, when the evaporator outlet air temperature falls below 3°C, _R14 becomes larger than _R14B , and the comparator output 31a becomes the "Lo" level, so the normally open contact 35a of the relay 35 becomes open, and the electromagnetic clutch 13 is cut off, and the operation of the compressor 12 is stopped.
This prevents the evaporator 5 from frosting.

Next, when the ambient temperature of the vehicle becomes lower than 24°C and the thermistor resistance value _R19 of the temperature sensor 19 becomes larger than _R19B , the comparator output 36a becomes "Lo".
level, and the normally closed contact 40a of the relay 40 is closed, so the solenoid valve 16 is energized. Therefore, the valve body 16e of the electromagnetic valve 16 is attracted by the coil 16d, and closes the discharge pressure inlet 16b while opening the suction pressure inlet 16a.
The valve body 115a of the on-off valve 115 is pressed by the spring 115b to open the port P.

Thereby, the discharge capacity of the compressor 12 is set to a small capacity.

Under the above conditions, the evaporator outlet air temperature is 4℃
If higher, the thermistor resistance value of the temperature sensor 14
R ₁₄ becomes smaller than R _14A , comparator output 3
1a becomes the "Hi" level, the normally open contact 35a of the relay 35 is closed, and the electromagnetic clutch 13 is connected. Therefore, the compressor 12 operates with a small discharge capacity.

Then, when the evaporator outlet air temperature falls below 3°C, _R14 becomes larger than _R14B , and the comparator output 31a becomes the "Lo" level, so the normally open contact 35a of the relay 35 becomes open, and the electromagnetic clutch 13 is cut off, and the operation of the compressor 12 is stopped.
This prevents the evaporator 5 from frosting.

As described above, in this embodiment, when the ambient temperature of the vehicle is high and cooling capacity is required, the compressor 12 is
The evaporator 5 is controlled to prevent frosting by alternately switching between high-capacity operation and stopping of the compressor 12. On the other hand, when the ambient temperature of the vehicle is low and cooling capacity is not required as much, the compressor 12 is switched between low-capacity operation and operation. The frost prevention of the evaporator 5 is controlled by switching the stops alternately. Note that it is also possible to replace the switching between large-capacity operation and operation stop when the ambient temperature of the vehicle is high with switching between large-capacity operation and small-capacity operation.

FIG. 11 shows another embodiment, in which the potential is determined by the thermistor resistance value _R14 of the temperature sensor 14.
Adding a comparator 41 that takes V ₁ as an input signal,
The output 41a of the comparator 41 turns the relay 42 on and off, thereby controlling the operation of the solenoid valve 16. Since the reference potential V ₅ of the comparator 41 is set lower than the reference potential V ₂ of the comparator 31 (V ₅ <V ₂ ), the outputs 31a, 41a of both the comparators 31, 41 are the thermistor resistance value R of the temperature sensor 14. ₁₄ as shown in Figure 12.

On the other hand, the output 36a of the comparator 36 has the same characteristics as shown in FIG.
Turn on and off the transistor 43 by a,
The operation of the relay 42 is controlled.

Next, the operation of this embodiment will be explained. If the ambient temperature of the vehicle is now higher than 26° C. and the resistance value R ₁₉ of the temperature sensor 19 is smaller than R _19A , the output 36a of the comparator 36 becomes “Hi” level and the transistor 43 is turned off. At this time, if the evaporator outlet air temperature is higher than 6°C, the two comparators 31,
The outputs 31a and 41b of the compressor 41 both become "Hi" level, the relay 35 is energized, its normally open contact 35a is closed, and the electromagnetic clutch 13 is connected, so that the compressor 12 is operated. At the same time, the relay 42 is also energized and its normally closed contact 42a is opened, so the solenoid valve 16 is not energized and the compressor 1
2 performs full operation with large capacity (100% capacity). Next, when the evaporator outlet air temperature gradually decreases to below 5°C and the value of _R14 becomes higher than _R14D , the comparator output 41a becomes "Lo".
, the relay 42 turns on, the solenoid valve 16 operates, and the compressor discharge capacity becomes small (30% to 50%). Here, if the evaporator outlet air temperature becomes lower than 3°C and the value of _R14 becomes higher than _R14B , the comparator output 31a becomes "Lo", the relay 35 is turned off, and the electromagnetic clutch is turned off. 13 is cut off, the operation of the compressor 12 is stopped. As a result, the temperature of the evaporator blowing air gradually increases, and the above operation is performed in reverse, and the switching between operation stop ← → small capacity operation ≓ large capacity operation is repeated.

On the other hand, when the ambient temperature of the vehicle becomes lower than 24℃,
When R ₁₉ becomes larger than R _19B , the comparator output 36a becomes "Lo" and the transistor 43 turns on, forcing the comparator output 41a to "Lo", so the relay 42 turns on and the solenoid valve 16 turns on. The compressor 12 is activated and the capacity of the compressor 12 becomes small. This small capacity operation is then intermittent by the comparator output 31a. In other words, when the ambient temperature of the vehicle is low, switching between operation stop and low capacity operation is repeated.

Next, an embodiment of the second invention shown in the drawings will be described. The refrigeration cycle in the method of the present invention is the same as in the first invention. FIG. 13 schematically shows the entire control system of the method of the present invention.

In the embodiment of the present invention, a rotation speed sensor 61 senses the rotation speed of an on-vehicle engine 60 that is directly connected to a compressor 12 and drives the compressor 12, and a signal having a frequency proportional to the rotation speed is sent to a frequency-voltage converter. 62 converts it into a voltage signal, obtains a voltage corresponding to the number of revolutions, and inputs it to the control circuit 15, which detects a signal corresponding to the outside temperature detected by the temperature sensor 19, and the air temperature immediately after the evaporator 5. These signals are input to the control circuit 15 along with the signals sensed by the temperature sensor 14 of
3 to stop the operation of the compressor 12.

The rest of the configuration is the same as the embodiment of the first invention shown in FIG. 4a, so the explanation will be omitted.

FIG. 14 shows a specific example of the control circuit 15 of the present invention. In the embodiment of the first invention shown in FIG. 5, an engine rotation speed sensor 61, a frequency voltage converter 62 that converts the frequency sensing signal sensed by the sensor into a DC voltage, a comparator 65 that inputs the signal, The difference is that a transistor 66 is added. The comparator 65 is
Reference potential determined by signal voltage V ₇ corresponding to engine speed and resistance values of resistors 68 and 69
_V8 is input, and the output 65a of the comparator 65 is determined by the values of _V7 and _V8 .

This output 65a causes the transistor 6 to
6 and 67 are turned on and off to intermittently energize the relay 40, thereby controlling the operation of the solenoid valve 16. As the rotation speed sensor 61, for example, an intermittent signal of an ignition coil, a generator, a photoelectric tachometer, etc. can be used.

The operations of the comparators 31 and 36 are the same as in the first invention, and the relationship between the changes in the thermistor resistance values R ₁₄ and R ₁₉ and the comparator outputs 31a and 36a is as follows.
The settings are as shown in FIGS. 15a and 15b.

The input/output characteristics of the frequency-voltage converter are shown in Figure 15c.
The relationship between the change in engine speed and the comparator output 65a is shown in Fig. 15d.
The settings are as shown below.

As shown in Fig. 15c, when the engine speed increases from 1200 rpm, for example, the comparator input signal
When V ₇ becomes lower than the reference potential V ₈ , the comparator output 65a becomes "Hi" level as shown in FIG.
Comparator input signal V ₇ below 1000rpm
When _V8 rises above the reference potential V8, the comparator output 65a becomes the "Lo" level.

Next, the operation of the control method of the present invention will be explained.

If the ambient temperature of the vehicle is now higher than 26°C and the thermistor resistance value R ₁₉ of the temperature sensor 19 is smaller than R _19A ,
Comparator output 36a becomes "Hi" level,
The transistor 67 is turned on to energize the relay 40, the normally closed contact 40a of the relay 40 is opened, and the solenoid valve 16 is not energized. Therefore, the discharge capacity of the compressor 12 is set to a large capacity (100% capacity).
At this time, if the engine speed is lower than 1000 rpm, the output 65a of the comparator 65 becomes "Lo".
level and turns off the transistor 66, so the control of the solenoid valve 16 is not affected. That is, the discharge capacity of the compressor 12 is set to a large capacity.

Conversely, when the engine speed becomes higher than 1200 rpm, the output 65a of the comparator 65 becomes "Hi" level, the transistor 66 is turned on, and the output 36a of the comparator 36 is forced to become "Lo" level. Therefore, the transistor 67
is turned off, the operating current of the relay 40 is briefly cut off, the normally closed contact 40a is closed, the solenoid valve 16 is energized, and the compressor 12 is set to a small capacity (30% to 50%).

On the other hand, when the ambient temperature of the vehicle is lower than 24°C and the thermistor resistance value _R19 of the temperature sensor 19 is greater than _R19A , the comparator output 36a becomes "Lo" level, the transistor 67 is turned off, and the relay 40 is activated. The current is suddenly cut off, the normally closed contact 40a is closed, the solenoid valve 16 is energized, and the discharge capacity of the compressor 12 is set to a small capacity.

At this time, regardless of the engine speed, that is, the level of the comparator output 65a, and therefore whether the transistor 66 is on or off, the comparator output 36a is always at the "Lo" level.
The discharge capacity of the compressor 12 is set to a small capacity regardless of the engine speed.

As described above, the discharge capacity of the compressor 12 is set to a large capacity only when the ambient temperature of the vehicle is higher than 26°C and the engine speed is lower than 1000 rpm, and the discharge capacity of the compressor 12 is set to a large capacity. In cases other than the above conditions, the discharge capacity of the compressor 12 is
The capacity is set to small.

When the air temperature immediately after the evaporator is higher than 4°C, the comparator output 31a becomes "Hi" level, the normally open contact 35a of the relay 35 is closed, the electromagnetic clutch 13 is connected, and the compressor 1
No. 2 is in operation at the above-mentioned set capacity. On the other hand, when the air temperature immediately after the evaporator drops below 3°C, the comparator output 31a becomes "Lo" level.
By opening the normally open contact 35a of the relay 35, the electromagnetic clutch 13 is disconnected and the operation of the compressor 12 is stopped. This prevents the evaporator 5 from frosting.

As described above, in this embodiment, when the ambient temperature of the vehicle is high and the cooling load is large, and the engine speed is low and the compression capacity of the compressor 12 is small, the compressor 12 is operated at a high capacity and the operation is stopped. Control the frost prevention of the evaporator 5 by switching alternately,
In addition, the system compensates for the lack of cooling capacity and operates with an appropriate cooling capacity according to the cooling load.On the other hand, when the ambient temperature of the vehicle is low and the cooling load is small, or when the engine speed is high and the compression capacity is large, Compressor 12
The evaporator 5 is controlled to prevent frosting by alternately switching between small-capacity operation and operation stop, and excessive cooling capacity is suppressed to operate at an appropriate cooling capacity according to the cooling load.

Note that it is also possible to replace the switching between high-capacity operation←→operation stop when the ambient temperature of the vehicle is high and the engine speed is low with switching between high-capacity operation←→low-capacity operation.

FIG. 16 shows another embodiment.
The other embodiment of the first invention shown in the figure includes a rotation speed sensor 61 of an engine 60, a frequency voltage converter 62 that converts the frequency sensing signal into a DC voltage, a comparator 65 that inputs the signal, and a transistor 66. The difference is that is added.

The functions and purposes of the comparators 41, 31, and 36 are the same as those of the first invention, and the characteristics are the same as those of the 17th invention.
The settings are as shown in Figures a and b.

Furthermore, the function and purpose of the comparator 65 are as follows:
This is the same as in the previous embodiment of the invention, and the characteristics are set as shown in FIG. 17c.

Next, the operation of this embodiment will be explained.

If the ambient temperature of the vehicle is now higher than 26°C and the resistance value _R14 of the temperature sensor 19 is smaller than _R19A , the output 36a of the comparator 36 becomes "Hi" level.
Transistor 43 is turned off. At this time, if the engine speed is less than 1000 rpm, the output 65a of the comparator 65 becomes "Lo" level and the transistor 66 is turned off.

In this case, the action of the comparators 31 and 41 provides the same operating mechanism as the embodiment described in FIG. 12. That is, when the evaporator outlet air temperature is higher than 6° C., the compressor 12 operates at full capacity (100% capacity). When the evaporator outlet air temperature gradually decreases to below 5℃ and above 3℃, the compressor discharge capacity will decrease to a small capacity (30% to 50℃).
%), and the compressor 12 operates in this state.

Further, when the temperature of the evaporator air discharged falls below 3° C., the operation of the compressor is stopped by the action of the comparator 31. Conversely, when the evaporator outlet air temperature rises, the above operation is performed in reverse. As a result, switching between high capacity operation←→low capacity operation←→operation stop is repeated.

Further, when the engine speed is higher than 1200 rpm, the output 65a of the comparator 65 becomes "Hi" level, and the transistor 66 is turned on. Therefore, the output 41a of the comparator 41 is forced to the "Lo" level, the operating current of the relay 42 is cut off, the normally closed contact 42a is closed, the solenoid valve 16 is energized, and the discharge capacity of the compressor 12 is reduced. The capacity is set to small. In this case, the evaporator outlet air temperature is 4℃
When the temperature is higher than that, the comparator output 31a becomes "Hi" level, and the electromagnetic clutch 13 is connected, and the compressor operates in a small capacity state. Conversely, when the evaporator outlet air temperature is lower than 3°C, the comparator output 31a becomes "Lo". level, the electromagnetic clutch 13 is disengaged and the compressor is stopped.

On the other hand, when the ambient temperature of the vehicle becomes lower than 24℃,
When R ₁₉ becomes larger than R _19B , the comparator output 36a becomes “Lo” level and the transistor 43
is on, the comparator output 41a
is forced to the “Lo” level. Therefore, the compressor 12 is set to a small capacity state. At this time 4
1a is forced to “Lo” level, so 65
The level of a does not contribute to the selection of the discharge capacity of the compressor 12. That is, the discharge capacity of the compressor 12 is set to a small capacity regardless of the engine speed. Output 3 of a comparator 31 that senses the evaporator outlet air temperature and operates based on the signal.
Depending on the level of 1a, the compressor 12 will operate intermittently.

As mentioned above, when the ambient temperature of the vehicle is higher than 26°C and the engine speed is lower than 1000 rpm, the compressor operates in high capacity operation, low capacity operation, or Operation/stop is switched and controlled. In contrast, the ambient temperature of the vehicle is 24℃.
lower or engine speed
When the speed rises above 1200 rpm, the compressor is controlled to be switched between small capacity operation and operation stop, depending on the temperature of the evaporator outlet air.

In the embodiments according to the first and second inventions described above, the air temperature immediately after the evaporator is sensed and controlled, but the refrigerant pressure in the evaporator, the refrigerant temperature, or the evaporator fin or may sense the surface temperature of the refrigerant pipe and use this as a control signal for capacity control.

In addition, if the resistor 37 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 ambient temperature of the vehicle, the purpose of controlling the room temperature is not only to prevent frosting of the evaporator 5. The present invention can also be applied to

The present invention can also be carried out in the same manner even if the temperature sensor 19 is installed in the air suction part of the ventilation casing 11 (the left end in FIG. 4) to sense the suction air temperature instead of the ambient temperature of the vehicle. can.

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

As described above, according to the present invention, in addition to sensing the air temperature immediately after the evaporator, the ambient temperature or intake air temperature of the vehicle is also sensed, or the engine rotation speed is also sensed, and these sensing signals are used. Since the compressor capacity is controlled in stages according to the load and the stoppage of the compressor is controlled, the refrigeration cycle can be operated at the optimal capacity according to the load or engine speed at that time. This has the great effect of significantly reducing the power consumption and noise of the compressor. In particular, in the present invention, the ambient temperature or intake air temperature of the vehicle is sensed, and when these sensed temperatures are low, the compressor capacity is reduced to prevent excessive cooling and effectively realize power savings.

Furthermore, if the engine speed is detected,
When driving at high speeds, the compressor capacity is reduced to prevent excessive cooling capacity; on the other hand, when driving at low speeds and the ambient temperature of the vehicle is high, the compressor capacity is increased to prevent insufficient cooling capacity. This can effectively save power.

[Brief explanation of the drawing]

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. Characteristic diagram showing changes in pressure and air temperature immediately after the evaporator, Figure 4a is a block diagram showing the overall control system of the device of the present invention, and Figures 4b and c are temperature sensors for sensing the ambient temperature of the vehicle. FIG. 5 is an electric circuit diagram showing a specific configuration of the control circuit 15 of the device of the present invention, and FIGS. Fig. 7 is a cross-sectional view showing an embodiment of the compressor used in the present invention, Fig. 8 is a cross-sectional view showing the configuration of the compressor internal capacity variable member, and Fig. 9 a and b are used in the present invention. An explanatory diagram showing a compressor capacity variable mechanism, FIG. 10 is a sectional view of a solenoid valve used in one embodiment of the present invention, FIG. 11 is an electric circuit diagram of another embodiment of the present invention, and FIG. The operating characteristic diagram of the comparators 31 and 41 shown in Fig. 11 and Fig. 13 are as follows.
FIG. 14 is an electric circuit diagram showing the specific configuration of the control circuit 15 of the second invention device, and FIG. 15 a, b, and d are in FIG. FIG. 15c is a characteristic diagram of the frequency-voltage converter, FIG. 16 is an electric circuit diagram of another embodiment of the second invention, and FIG. The operating characteristics diagram of the comparators 31 and 41 shown in FIG. 17, b and c are the first
FIG. 6 is an operational characteristic diagram of the comparators 36 and 65 shown in FIG. 5... Evaporator, 12... Compressor, 13... Electromagnetic clutch, 14, 19... Temperature sensor, 15...
Control circuit, 16... Solenoid valve, 18... Capacity variable member.

Claims (1)

[Scope of Claims] 1. A compressor that receives driving force from an automobile engine and sucks, compresses, and discharges refrigerant; and an electromagnetic device that switches between transmitting and non-transmitting the driving force from the automobile engine to the compressor. a clutch; a variable capacity member for changing the discharge capacity of the compressor; a driving means for driving the variable capacity member; a first sensing means for sensing temperature or refrigerant pressure related to the degree of cooling of the evaporator; a second sensing means for sensing the ambient temperature of the compressor; and a second sensing means for sensing the ambient temperature of the compressor; control means for controlling an electromagnetic clutch to switch between operating and non-operating the compressor, the control means controlling at least one of the driving means and the electromagnetic clutch based on a sensing signal from the first sensing means; is controlled to control the capacity and activation/deactivation of the compressor to prevent frosting of the evaporator, and based on the sensing signal from the second sensing means, the ambient temperature of the automobile is higher than a predetermined temperature. at least one of the driving means and the electromagnetic clutch is controlled to control the compressor between large capacity and non-operation, and when the ambient temperature of the automobile is below a predetermined temperature, the driving means and the electromagnetic clutch are controlled. An air conditioner for an automobile, characterized in that the compressor is controlled between a small capacity and a non-operating state by controlling at least one of the above. 2 The control means controls at least one of the drive means and the electromagnetic clutch to control the capacity and operation/non-operation of the compressor based on the sensing signal from the first sensing means, thereby controlling the evaporator. In order to prevent frosting of the compressor, and based on the sensing signal from the second sensing means, when the ambient temperature of the automobile is higher than a predetermined temperature, the driving means is controlled to increase the capacity of the compressor, and the electromagnetic controlling a clutch to switch the compressor between high capacity operation and non-operating operation, and operating the drive means to reduce the capacity of the compressor to a small capacity when the ambient temperature of the vehicle is below a predetermined temperature; 2. The air conditioner for an automobile according to claim 1, wherein said electromagnetic clutch is controlled to switch said compressor between low capacity operation and non-operation. 3. The control means controls at least one of the drive means and the electromagnetic clutch based on the sensing signal from the first sensing means to control the capacity and operation/non-operation of the compressor to control the evaporation. and when the ambient temperature of the automobile is higher than a predetermined temperature based on the sensing signal from the second sensing means, the driving means and the electromagnetic clutch are controlled to operate the compressor with a large capacity. control between capacity switching from operation to small capacity operation and non-operation, and when the ambient temperature of the automobile is below a predetermined temperature, the driving means is controlled to reduce the capacity of the compressor, and the electromagnetic clutch is controlled to reduce the capacity of the compressor; 2. The air conditioner for an automobile according to claim 1, wherein the compressor is controlled to switch between small capacity operation and non-operation. 4. A compressor that receives driving force from an automobile engine and sucks in, compresses, and discharges refrigerant; an electromagnetic clutch that switches between transmitting and non-transmitting the driving force from the automobile engine to the compressor; and the compressor. a variable capacity member that changes the discharge capacity of the variable capacity member; a drive unit that drives the variable capacity member; a first sensing unit that senses temperature or refrigerant pressure related to the degree of cooling of the evaporator; and a first sensing unit that senses the ambient temperature of the vehicle. a second sensing means; a third sensing means for sensing the rotational speed of an automobile engine; and controlling the driving means in response to sensing signals from the first sensing means, the second sensing means, and the third sensing means. to variably control the capacity of the compressor,
and control means for controlling the electromagnetic clutch to switch between operating and non-operating the compressor, the control means controlling the driving means and the electromagnetic clutch based on the sensing signal from the first sensing means. At least one of them is controlled to control the capacity and operation/non-operation of the compressor to prevent frosting of the evaporator, and the ambient temperature of the automobile is determined based on the sensing signal from the second sensing means. When the temperature is above a predetermined temperature, at least one of the driving means and the electromagnetic clutch is controlled to control the compressor between large capacity and non-operation; and when the ambient temperature of the automobile is below the predetermined temperature, the driving means is controlled. controlling at least one of the means and the electromagnetic clutch to control the compressor between a small capacity and a non-operating state; when the number of revolutions of the automobile engine is equal to or higher than a predetermined number of revolutions, controlling at least one of the driving means and the electromagnetic clutch to control the compressor between high capacity and non-operation; An air conditioner for an automobile, characterized in that the compressor is controlled between a small capacity and a non-operating state by controlling at least one of a driving means and the electromagnetic clutch. 5. The control means controls at least one of the drive means and the electromagnetic clutch based on the sensing signal from the first sensing means to control the compression capacity and activation/non-activation of the evaporation. When the ambient temperature of the automobile is above a predetermined temperature based on the second sensing signal, and when the rotation speed of the automobile engine is below the predetermined rotation speed based on the sensing signal from the third sensing means. , the driving means is controlled to increase the capacity of the compressor, and the electromagnetic clutch is controlled to switch the discharge capacity of the compressor between high capacity and non-operation, and the second sensing is performed. Based on the sensing signal from the means, when the ambient temperature of the vehicle is below a predetermined temperature, or
Based on the sensing signal from the third sensing means, when the rotational speed of the automobile engine is higher than a predetermined rotational speed, controlling the driving means to reduce the capacity of the compressor and controlling the electromagnetic clutch; 5. The air conditioner for an automobile according to claim 4, wherein the compressor is controlled to be switched between a small capacity operation and a non-operation. 6. The control means controls at least one of the drive means and the electromagnetic clutch based on the sensing signal from the first sensing means to control the capacity and operation/non-operation of the compressor. The evaporator is prevented from frosting, and based on the sensing signal from the second sensing means, when the ambient temperature of the car is higher than a predetermined temperature, and based on the sensing signal from the third sensing means, the rotation of the automobile engine is stopped. when the number of revolutions is less than a predetermined number of revolutions, controlling the driving means and the electromagnetic clutch;
controlling the capacity of the compressor from high-capacity operation to low-capacity operation and switching between operation and non-operation, and based on the signal from the second sensing means, when the ambient temperature of the automobile is below a predetermined temperature, or Based on the sensing signal from the third sensing means, when the rotation speed of the automobile engine is equal to or higher than a predetermined rotation speed, the driving means is controlled to have a capacity smaller than that of the compressor;
5. The air conditioner for an automobile according to claim 4, wherein said electromagnetic clutch is controlled to switch said compressor between low capacity operation and non-operation.