JPS6355452B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for adjusting the cooling capacity of an automobile air conditioner using a variable capacity compressor equipped with a variable capacity member that changes the discharge capacity of a heat absorbing medium.

Conventionally, in the refrigeration cycle of an automobile air conditioner, it has been customary to use a compressor with a constant discharge capacity of an endothermic medium. Therefore, when controlling the temperature or humidity of an air conditioner, a method is used in which the compressor is alternately turned on and off.

As a result, shocks are applied to the mechanical system when the vehicle is started or stopped, and the temperature of the heat absorber pulsates, resulting in undesirable temperature fluctuations within the cabin, or additional measures are required to prevent these problems. , and other problems arose.

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, it is an object of the present invention to provide a cooling capacity adjustment method that prevents sudden changes in power consumption and temperature of a heat absorber.

In addition, it is an object of the present invention to provide a cooling capacity adjustment method that can suppress power consumption to near the minimum necessary level by referring to the required amount of cooling capacity.

According to the present invention, the variable displacement compressor is configured to be driven by an on-vehicle engine as a rotating power source via a clutch to change the discharge capacity of the heat absorbing medium, and the heat absorbing medium discharged from the compressor is A variable cooling capacity type refrigeration cycle is used in which a heat absorber through which a medium passes is placed in a ventilation duct. In this refrigeration cycle, the temperature of the air generated on the secondary side of the heat absorber is changed stepwise or continuously in accordance with the position of the variable capacity member of the compressor. In order to further adjust the cooling capacity, the actual cooling temperature in the heat sink (secondary air temperature) and the air temperature introduced and supplied to the heat sink (primary air temperature) are compared with a reference value corresponding to the required amount of cooling capacity. Based on the results, it is determined whether the clutch should be engaged or not and the capacity of the variable displacement compressor.

In the embodiments of the present invention described below, the overall configuration of an automotive air conditioner to which the present invention is applied, an example of a variable displacement compressor, and a system that responds to electrical measurements of primary air temperature and secondary air temperature will be described. This disclosure discloses an example of an electric control device that adjusts whether or not a clutch is engaged and the position of a variable capacity member of a compressor.

In FIG. 1 showing the overall configuration, a compressor 1 is of a variable displacement type, and receives rotational power from an on-vehicle engine (not shown) via a clutch 2, causing an internal piston to reciprocate and discharging and circulating an endothermic medium. do. As will be described later, the compressor 1 incorporates a variable capacity member, the position of which is adjusted by a servo motor 3 and a worm gear 4. The position of the variable member is detected electrically by a potentiometer 5 and connected to an input resistor network of an electrical control circuit 6.

A refrigeration cycle including a compressor 1 includes a condenser 7, a receiver 8, an expansion valve 9, and an evaporator 10 as a heat absorber.
It has a vapor compression refrigeration cycle.
The evaporator 10 is installed in a ventilation duct 11 that supplies conditioned air toward the vehicle interior. This evaporator 1
0 is cooled by passage of an endothermic medium, and blower 1
2, heat is removed from the air flow introduced from the vehicle interior or outside the vehicle interior and flowing toward the vehicle interior as shown by the white arrow, thereby cooling the vehicle. Here, the cooling capacity changes depending on the flow rate of the endothermic medium passing through the evaporator 10. The cooled airflow is sent to the passenger compartment either as it is or after being appropriately reheated using a reheater (not shown) such as an emics type reheater.

Next, the configuration and operation of the variable displacement compressor 1 according to the present invention will be explained in detail.

2 to 4, a shaft 101 is connected to an automobile engine serving as a drive source via an electromagnetic clutch 2 shown in FIG. 1 and a V-belt (not shown), and is rotated by the driving force of the engine. 102 is a swash plate that rotates together with the shaft 101, and the rotation of this swash plate 102 is caused by the rotation of the shaft 101.
3 to cause the piston 104 to reciprocate. 1
05, 106 is a housing, and the piston 10
It has a cylinder part 107 that supports the reciprocating motion of the four cylinders, and is divided into two parts, the front and the rear, and is die-cast from aluminum or the like. 108 is a suction passage chamber formed within the housings 105 and 106. As shown in FIGS. 3 and 4, the cylinder portion 107 is located at five locations 107a, 107b, 1
07c, 107d, and 107e are formed, and only the lowermost cylinder parts 107c and 107d are spaced at an angle of 88°, and the spaces between the other cylinder parts are all 68°. . Further, the suction passage chamber 108 is formed between each cylinder part 107 as shown in FIG. It communicates with the outlet side refrigerant circuit of No. 10.

Reference numerals 109 and 110 denote side housings, which are disposed outside the housings 105 and 106 with valve plates 111 and 112 in between. A suction chamber 113 is formed in a portion of the side housings 109 and 110 that directly communicate with each other through a suction side communication hole (not shown), and a portion of the side housings 109 and 110 that faces the piston 104 on the inner periphery of the suction chamber 113 is formed. A discharge chamber 114 is formed at the position. This discharge chamber 114 is connected to the housing 10 through the discharge side communication holes (not shown) of the valve plates 111 and 112.
It communicates with the discharge passage chamber 114a (FIG. 4) of No. 5,106. 115, 116 are valve plates 11
1,112 and the housings 105, 106. A U-shaped elastic metal plate (not shown) is located at a position facing the piston 104 of the elastic metal plate 115, 116, and is made of an elastic metal such as spring steel. A notch is provided to form a suction valve.

In addition, the housings 105 and 106, the side housings 109 and 110, and the valve plate 11
1 and 112 are integrally connected by a through bolt 117, and the through bolt 117 passes through the suction passage chamber 108 within the housings 105 and 106 to facilitate assembly.

118 and 119 are radial bearings using normal needle bearings, and housing 1
An outer race is fixed to 05 and 106 to rotatably hold the shaft 101. 1
Thrust bearings 20 and 121 are located between the center portions of the housings 105 and 106 and the swash plate 102, so that the force applied to the swash plate 102 in the thrust direction (axial direction), that is, the swash plate 102
This supports the reaction force received when 04 is communicated back and forth.

Reference numeral 122 denotes a shaft seal, which is located on the drive source side (in other words, on the electromagnetic clutch 2 side) of the side housings 109 and 110.
It is located between the compressor 9 and the shaft 101 to maintain airtightness so that the refrigerant gas and lubricating oil inside the compressor do not leak to the outside.

Reference numeral 123 denotes a holder for the servo motor 3, which is fixed to the rear side housing 110 with screws 124. The worm gear 4 of the servo motor 3 is the third
As shown in the figure, it is connected to an operating shaft 126 by a worm gear 125. This operating shaft 126 is arranged between the rear valve plate 112 and the front valve plate 111 by utilizing the space between the lowermost cylinder parts 107c and 107d, and is located between the valve plate 111 of the operating shaft 126.
Spur gears 127 and 128 are attached to portions adjacent to wheels 1 and 112, respectively.

Reference numerals 129 and 130 are annular variable rings that constitute variable capacity members;
9,130 is housing 105,106,
It is disposed within a cylindrical space provided on the outer periphery of the cylinder portion 107 so as to be concentric with the compressor drive shaft 101 as much as possible. The rotational force of the operating shaft 126 is applied to the variable rings 129, 130 through the spur gears 127, 128.
The rotation is transmitted through teeth 129a, 130a provided on the inner periphery of the variable rings 129, 130.

Two bypass holes 131a and 131b are provided in the wall surface of each cylinder portion 107 at positions closest to the variable rings 129 and 130, and shaft holes 131a and 131b are provided in the bypass grooves 132a and 132b and in the variable rings 129 and 130, respectively. Bypass groove 133 arranged parallel to 101 and variable ring 1
The inner circumferential surfaces of the compressors 29 and 130 communicate with a bypass port 135 formed in the housings 105 and 106 through a bypass groove 134 provided all around the center side of the compressor.
Furthermore, this bypass port 135 is connected to the housing 10.
5, 106 is formed so as to be electrically connected to the suction passage chamber 108 provided in the suction passage chamber 106.

In this embodiment, the bypass holes 131a and 131b drilled in the wall surface of the cylinder 107 are arranged at positions that divide the cylinder volume into three equal parts, and either only the port 131b on the center side of the compressor, or both the ports 131a , 131b are arranged to face the bypass grooves 132a, 132b in accordance with the rotation angle of the variable rings 129, 130 (see FIGS. 5 and 6).

Further, the bypass grooves 132a, 132b are connected to the five cylinders 107a, 107b, 107c, 107.
d and 107e, respectively, as shown in FIG.
The cylinders 107 are provided with different lengths in the circumferential direction of the cylinder 107 and communicate with the suction passage chamber 108 according to the rotation angle of the variable rings 129 and 130.
It has been devised so that the number of That is, in the case of this embodiment, when the rotation angle is 0°, all the bypass holes 131a and 131b (20 holes in total) are located directly opposite the bypass grooves 133 of the variable rings 129 and 130, and this bypass groove 133, a bypass groove 134, and a bypass port 135 of the housings 105, 106 to communicate with the suction passage chamber 108, so that the cylinder volume that performs net compression work is minimized. When the rotation angle is 4 degrees, the bypass hole 13 provided in the cylinder 107e
Only the bypass hole 1a is not in communication with the bypass groove 132a, and the remaining bypass holes 131a and 131b are both in communication with the suction passage chamber 108. Thereafter, as the rotation angle increases by 4 degrees such as 8 degrees, 12 degrees, etc., the number of bypass holes that do not communicate with the suction passage chamber 108 increases one by one. Only the bypass holes 131b that have been connected to each other are in communication with the suction passage chamber 108 via the bypass groove 132b, and the others are not connected, and when the rotation angle reaches 40 degrees, all the bypass holes 131a,
131b is closed and the cylinder volume for compression work is maximized. This variable ring 129, 13
The relationship between the zero rotation angle and the cylinder volume that does the net compression work is shown in Figure 8, and the maximum volume
The cylinder volume can be finely controlled in 10 steps between Vmax and 1/3vmax. This indicates that the power consumption in the compressor is controlled in 10 stages.

The rotational positions of the variable rings 129, 130 can be detected as electrical signals by the potentiometer 5 of the position detection device 5'. That is, the worm gear 125 formed on the end surface of the operating shaft 126 is the operating gear 2 of the position detection device 5'.
41, and the operating shaft 12
6 (worm gear 125), the potentiometer resistance value of the position detection device 5' is varied,
As a result, an electric signal determined depending on the position of the variable rings 129, 130 is output. The position detection device 5' is fixed to the side housing 110 by a pin 243 via a stay 242 formed on the side surface thereof. Note that storage grooves are formed in the side housing 110 at a portion where the position detection device 5' is held and at a portion where the aforementioned servo motor 3 is held, so that the servo motor 3 and the position detection device 5' are etc., and the side housing 11
The servo motor 3 and the like are designed not to protrude too much from the zero surface. Although not shown, the servo motor 3, worm gears 4, 125, position detection device 5', etc. are covered with a cover (not shown) to prevent dust.

Next, to explain the operation of only one part of the swash plate compressor, the electromagnetic clutch 2 is connected and the shaft 1 is connected.
01 and the swash plate 102 begin to rotate, the refrigerant gas vaporized in the evaporator 10 flows through the housing 105,
It is introduced into the suction passage chamber 108 from an inlet (not shown) provided in the valve plate 111,
The suction chamber 11 of the front and rear side housings 109, 110 passes through the suction side communication hole 112 (not shown).
Flows into 3. The piston 10 reciprocates within the cylinder portion 107 as the swash plate 102 rotates.
4 is in the suction stroke, refrigerant gas, which is an endothermic medium, is sucked into the cylinder portion 107 from suction ports in the valve plates 111 and 112 through suction valves formed in the elastic metal plates 115 and 116. Next, when the piston 104 moves to the compression stroke, the suction port is closed by the suction valve, and the cylinder portion 10
The refrigerant gas in the side housing 1 is compressed by the piston 104 and passes through the discharge ports of the valve plates 111 and 112 and the discharge valve (not shown).
09, 110, flows again into the discharge passage chamber 114a in the housings 105, 106 through the discharge side communication holes (not shown) of the valve plates 111, 112, and then flows into the discharge passage chamber 114a in the housings 105, 106.
The refrigerant gas, which has become high temperature and high pressure in the compression stroke, is sent to the condenser 7 from unillustrated discharge ports of the housings 105 and 106.

Therefore, the discharge flow rate of the refrigerant gas is controlled by variable rings 129 and 130 corresponding to the rotation of the servo motor 3.
The evaporator 10 can be changed in 10 steps depending on the rotation angle of
The cooling capacity can be adjusted.

In FIG. 1, a thermistor 13 for sensing the temperature of primary air supplied to the evaporator 10 is installed upstream of the evaporator 10, and a thermistor 13 is installed downstream of the evaporator 10.
A thermistor 14 is installed to sense the temperature of the secondary air cooled by the air. Both thermistors 13,1
4 indicates the electrical resistance depending on the temperature of the primary air and secondary air, which are the atmospheres, respectively. Both thermistors 13,1
4 and the previously mentioned potentiometer 5 are connected in series on the input side of the electrical control circuit 6.
Furthermore, this series resistance circuit and the variable resistor 15 are connected in series. The voltage V ₁ at the connection point is input to the electric control circuit 6, which determines its operating characteristics and determines whether the servo motor 3 is in the forward or reverse direction.

The variable resistor 15 is used to change a reference value that predetermines the cooling capacity, but depending on the usage conditions, the resistance value can be fixed in advance at the time of shipment from the factory, or the temperature (not shown) of the air conditioner can be changed. The resistance value may be changed in conjunction with an adjustment lever or the like. In addition, in any state of use, in order to prevent frost from forming in the evaporator 10, the resistance value of the variable resistor 15 is set so as not to fall below a minimum value determined by the ratio of the resistance values of the thermistors 13 and 14. Should.

Electrical control circuit 6 drives servo motor 3 and energizing relay 16 of electromagnetic clutch 2 in response to voltage signal V ₁ . Here, one of the roles of the electric control circuit 6 is to detect the actual degree of cooling in the evaporator 10 from the temperature of the secondary air detected by the thermistor 14, and to balance this with the set reference value of the variable resistor 15. The capacity of the compressor 1 is adjusted by operating the servo motor 3 in accordance with the voltage signal v ₁ that changes accordingly. This means that the compressor 1 is operated at a minimum capacity so that the degree of cooling of the evaporator 10, which is determined by the set reference value of the variable resistor 15, is maintained.

The role of another electric control circuit 6 is to detect the temperature of the primary air detected by the thermistor 13, and when the temperature is lower than the set reference value of the variable resistor 15, the electromagnetic clutch 2 is cut off, and when it is high, the primary air temperature is detected. This is to connect the electromagnetic clutch 2. This is determined by the set reference value of the variable resistor 15 in the evaporator 10.
This means that the unnecessary operation of the refrigeration cycle is stopped when a degree of cooling of .

The two roles mentioned above are played by the thermistors 13 and 14.
Although both thermistors are connected in series and their individual resistance values cannot be detected independently, both thermistors have the same tendency (negative in the example) in temperature resistance, and in principle, the temperature resistance of the evaporator 10 This is cleverly shared in the electrical control circuit, with the knowledge that the temperature of the secondary air cannot be higher than that of the primary air. Note that it is desirable that the thermistor 13 has an increase in resistance value with respect to a temperature drop that is close to a quadratic characteristic, and the thermistor 14 has good linearity.

In FIG. 9, three comparators 17, each having a different operating point (threshold value), each having a voltage _V1 indicating the balance between the resistance value of the variable resistor 15 and the combined resistance value of the potentiometer 5 and thermistors 13 and 14, 1
It is commonly input to the inverting input terminals 8 and 19. The comparators 17, 18, and 19 are given operating points as voltages va, vb, and vc (where va>vb>vc) by a fixed resistance network connected to the non-inverting input terminal, and this operating point are the feedback resistors 17a and 1, respectively.
Hysteresis is provided by 8a and 19a.

Resistance components 5, 13, which determine the operation of this circuit
14, 15, an increase in voltage V ₁ indicates a downward adjustment of the cooling capacity, and a decrease in voltage V ₁ indicates an upward adjustment of the cooling capacity. Generally speaking, the drop in the primary or secondary air of the evaporator 10 is caused by the thermistor 1
3.14 is detected as an increase in the resistance value, and the circuit operates to reduce the cooling capacity or stop the cooling action. Furthermore, increasing the value of the variable resistor 15 means increasing the cooling capacity. The potentiometer 5 serves as a feedback function for the minor loop, and is useful for preventing hunting in the control system.
As described above, the maximum value of the variable resistor 15 is predetermined so as not to cause frost in the evaporator 10. Now, the role of the electric control circuit will be explained in detail assuming that the value of the variable resistor 15 is adjusted and fixed.

As shown in FIG. 10, the first comparator 17 with the highest operating point determines when the combined resistance R ₁ is the highest (R _K · R _F ), and outputs a signal corresponding to the determination result to the output line 17b. “Lo”, “Hi” level output signal 1
yields 7b'. That is, the temperature of the primary air of the evaporator 10 is low, and therefore the two thermistors 13, 1
When all 4 have high resistance values, the combined resistance value
The divided voltage v ₁ determined by the ratio of R ₁ and the reference value of the variable resistor 15 exceeds the first operating point va, and the output signal 1
7b' becomes the "Hi" level. However, when the temperature of the primary air is high to a certain extent, at least the thermistor 13 exhibits a low resistance value, the divided voltage v ₁ becomes smaller than the first operating point va, and the output signal 17b' becomes "Lo".
become the level.

The output signal 17b of the comparator 17 is given as a drive signal to the energizing relay 16 via the switching amplification stage 20, and the relay 16 drives the electromagnetic clutch 2.
The excitation coil 2a is energized and deenergized. Output signal 1
When 7b is at the "Lo" level, the relay 16 is energized, and the electromagnetic clutch 2 is energized through its closed and normally open contacts, becoming connected and causing the compressor 1 to rotate. On the other hand, when the output signal 17b becomes "Hi" level, the electromagnetic clutch 2 is deenergized and the compressor 1
to stop.

In other words, the primary air temperature is quite low and the combined resistance
If R ₁ is high enough, the compressor 1 is stopped, and when the primary air temperature increases, the compressor 1 is turned off by the clutch 2 at a point determined by the ratio to the reference value of the variable resistor 15.
It is rotated through the .

The second and third comparators 18, 19 determine the capacity of the compressor 1 in operating conditions. As shown in FIG. 10, the second comparator determines when the combined resistance R ₁ is medium (R _C , R _D ), and the third comparator determines when the combined resistance R ₁ is the lowest (R _A , R _B ).
When the temperature of the primary air is relatively high, the combined resistance R ₁ changes mainly depending on the resistance value of the thermistor 14, that is, the degree of cooling of the evaporator 10. Therefore, the divided voltage v ₁ shows a tendency to increase or decrease depending on the reference value of the variable resistor 15 and the actual degree of cooling. A high degree of specific cooling with respect to the reference value results in a high partial voltage v ₁ , while a low degree of specific cooling causes a decrease in the partial voltage v ₁ .

The second comparator 18 has a divided voltage v ₁ indicating the specific cooling degree.
When the voltage exceeds the operating point vb, the output is at the "Hi" level, otherwise the output is at the "Lo" level. The third comparator 19 becomes "Hi" when the divided voltage v ₁ exceeds the operating point v _C.
level, otherwise it will produce a “Lo” level output. The output signals 18b, 19b of these comparators are sent to the pair of drive stages 23 (23a, 23) of the servo motor 3 via switching amplification stages 21, 22, respectively.
b, 23c) and 24 (24a, 24b, 24c)
is applied to.

Therefore, the specific cooling degree increases and the partial voltage v ₁
exceeds the operating point vb and the output signal 18b of the second comparator 18 becomes "Hi" level, the drive stage 23
The transistors 23a to 23c become conductive, supplying a current _i1 to the servo motor 3, and the rotation of the motor shaft causes the variable rings 129, 130 of the compressor 1 to be turned on.
to reduce the capacity of the compressor. The position of the variable ring is fed back as the electrical resistance of the potentiometer 5, and when the combined resistance R ₁ is decreased and the divided voltage v ₁ is lowered below the operating point va,
The output signal of the second comparator 18 changes to "Lo" level, and the servo motor 3 stops.

On the other hand, the specific cooling degree is small and the partial voltage v ₁ is the operating point v _C
When the output signal 19 of the third comparator 19 becomes
b goes to the "Lo" level, each transistor 24a to 24c of the drive stage 24 becomes conductive, and current flows through the servo motor 3 and 2, causing the motor to rotate in the opposite direction. Therefore, the variable rings 129 and 130 of the compressor 1 rotate in a direction that increases the capacity of the compressor. At the same time, potentiometer 2
The electrical resistance of comparator 19 increases, so that when the divided voltage v ₁ exceeds the operating point v _C , the output signal 1 of comparator 19
9b changes to the "Hi" level, and the servo motor 3 stops.

In a state where the divided voltage _v1 is between the operating points vb and vc, the second comparator 18 produces a "Lo" level output, and the third comparator 19 produces a "Hi" level output. In this state, the drive stages 23 and 24 are all cut off, and the servo motor 3 is stopped.

In this way, the servo motor 3 moves the variable rings 129 and 1 to positions corresponding to the partial voltage v ₁ indicating the specific cooling degree.
30 and performs forward and reverse rotation so as to stop and maintain the dead area between the operating points vb and vc. Due to the change in the resistance of the potentiometer 5 as the variable ring rotates, the adjustment system temporarily stops, but as the capacity of the compressor 1 changes, the temperature of the secondary air in the evaporator 10 gradually changes. When the rotational speed of the compressor 1 changes depending on the operating condition of the automobile or when the ambient temperature of the condenser (FIG. 1, 7) changes, the cooling capacity changes and the temperature of the secondary air changes. This change is detected by the thermistor 14 as the actual secondary air temperature, and by raising and lowering the partial voltage _v1 ,
It causes the servo motor 3 to rotate again and stabilizes the regulating system in the new stationary state.

In this way, the electrical control circuit 6
The degree of cooling is detected based on the actual temperature of the secondary air, and the servo motor 3 is controlled from rotation to standstill to adjust the compressor capacity. As a general trend, the compressor capacity is adjusted to become smaller when the secondary air temperature is low and when the resistance value of the variable resistor 15 is large. Also, when the temperature of the primary air is low, the compressor capacity is adjusted to be small.

This device thus adjusts the capacity of the compressor 1 in response to the temperature of the secondary air in order to achieve the required cooling capacity determined by the variable resistor 15, and also adjusts the capacity of the compressor 1 in response to the temperature of the primary air to achieve the required cooling capacity determined by the variable resistance 15. Automatically operates to stop one operation.

Although one embodiment of the present invention has been described below, the present invention can also be applied to the following modifications.

(1) Regarding the compressor 1, in the above embodiment, the bypass holes 131a and 131b of the cylinder 107 were communicated with the suction passage chamber 108 via the bypass grooves 132a, 132b, 133, 134, etc.; Any space with low internal pressure, in other words, a space with suction pressure inside, may be used.Depending on the shape of the compressor, this communication point may be the suction chamber 113, the crank chamber (rotation of the swash plate 2) space) or in another cylinder 107 that is on the suction stroke.

(2) Although a 10-cylinder swash plate compressor is used in the above embodiment, it goes without saying that any swash plate compressor having a plurality of cylinders may be used. Further, in the above embodiment, the variable ring 12
9 and 130 are disposed within the cylindrical space on the outer periphery of the housings 105 and 106, but it goes without saying that they may also be disposed between the compressor drive shaft 101 and each cylinder 107.

(3) As long as the compressor 12 is of a variable capacity type, it is not limited to the swash plate type, and other types such as a vane type can be used.

(4) The variable capacity member is not limited to the variable rings 129 and 130, but can be changed into various forms depending on the type of compressor.

(5) As the drive device, in addition to the electric servo motor 3, a combination of a negative pressure diaphragm mechanism and a link mechanism, etc. can also be used.

(6) In the above example, the air temperature immediately after the evaporator was detected as the secondary air temperature of the evaporator 10, but in addition to this, the air temperature immediately after the evaporator was detected. Surface temperature may also be detected.
Furthermore, the evaporator refrigerant pressure may be detected instead of the evaporator refrigerant temperature.

(7) A setting resistor 15 is provided on the control panel of the air conditioner so that the user can manually operate the setting resistor 15.
If the user is allowed to freely set the resistance value of the compressor, the room temperature can be controlled by controlling the capacity of the compressor. Furthermore, when a reheater is disposed downstream of the evaporator 10, the resistance value may be changed depending on the position of a member that adjusts the amount of heating. Also, semi-fixed or fixed resistors may be used to provide a pre-adjusted resistance value.

(8) In order to detect the temperature of the primary air of the evaporator 1, in addition to using the thermistor 13 placed immediately in front of the evaporator 10, a temperature detector placed in a position that can detect the air temperature outside the passenger compartment and a temperature detector placed inside the passenger compartment are used. A temperature detector disposed at a position to detect the air temperature may be selected and used depending on the state of air introduction into the duct 11.

(9) The electric control circuit can be modified as shown in FIG. 11, for example. The first comparator 17' compares the signal voltage of the thermistor 13' which detects the temperature of the primary air of the evaporator 10 with the signal voltage of the variable resistor 15',
``Hi'' level output to disconnect the electromagnetic clutch 2 when higher than the reference value determined by
The voltage is applied to the amplification stage 20 (see FIG. 9). Also, the second and third comparators 18', 1
9' compares the signal voltage of the thermistor 14' that detects the temperature of the secondary air of the evaporator 10 with the signal voltage of the variable resistor 15', and outputs an output signal for rotating the servo motor 3 in forward and reverse directions through an amplification stage. 21, 22
(See Figure 9).
Note that the reference value given to the first comparator 17' and the second,
The reference values given to the third comparators 18' and 19' are not set using a common variable resistor 15', but are set using separate variable resistors, and the two variable resistors are linked together. Good too.

As described above, in the present invention, the compressor is operated, stopped, and operated in response to the temperature of the primary and secondary air of the heat absorber or a physical quantity correlated to the temperature, so as to obtain the required degree of cooling. By adjusting the capacity of the capacitor, it is possible to prevent shocks and temperature fluctuations in the mechanical system, and moreover, it has the excellent effect of not wasting power and energy.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of the apparatus of the present invention, and FIG. 2 is a cross-sectional view showing one embodiment of the compressor 1 used in the present invention, showing the shape taken along the line DD in FIG. 3. FIG. 3 is a side view of the compressor. Figure 4 is A of Figure 7.
-A cross-sectional view showing the relationship between the bypass hole and the bypass groove of the variable ring. FIG. 5 is a diagram showing the positional relationship of each bypass groove provided in the variable ring, and is a developed view in the direction of arrow B--B in FIG. 6. 6th
The figure is a sectional view taken along the line C-C in FIG. 5, and FIG. 7 is a sectional view showing the shape of the bypass groove corresponding to each cylinder.
Fig. 8 is an explanatory diagram showing the relationship between the rotation angle of the variable ring and the net cylinder volume that performs compression work, Fig. 9 is an electrical wiring diagram showing one embodiment of the electric control circuit 6 used in the present invention, and Fig. 10. 11 is an operating characteristic diagram of the comparators 17, 18, and 19 in the electric control circuit, and FIG. 11 is an electric wiring diagram showing a modification of the electric control circuit. 1... Variable capacity compressor, 2... Electromagnetic clutch, 3... Servo motor, 5... Potentiometer, 6... Electric control circuit, 10... Evaporator (heat absorber), 11... Ventilation duct , 13...Thermistor for detecting temperature of primary air, 14... Thermistor for detecting temperature of secondary air, 15... Variable resistor for setting reference value.

Claims (1)

[Claims] 1. A heat absorber that has a variable displacement compressor configured to change the discharge capacity of heat absorbing medium by using an on-vehicle engine as a rotational power source and is driven via a clutch to change the discharge capacity of heat absorbing medium, and through which the heat absorbing medium discharged from this compressor passes. A method for adjusting the cooling capacity of an automotive air conditioner arranged in a ventilation duct, the method comprising: a temperature value of primary air supplied to the heat absorber; and a temperature of secondary air that has absorbed heat in the heat absorber. in response to a value or a value of a physical quantity having a correlation with the temperature value, engaging the clutch when the temperature value of the primary air has a predetermined height compared to a predetermined reference value;
and a method for adjusting the cooling capacity of an automotive air conditioner, the method comprising adjusting the capacity of the compressor in accordance with a deviation between the temperature value of the secondary air or the value of a physical quantity having a correlation and the reference value.