JPH0760005B2 - Refrigeration cycle controller for air conditioning - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a control device for an air-conditioning refrigeration cycle used for cooling and dehumidifying action in a room to be air-conditioned, and is suitable for use in, for example, air-conditioning an interior of an automobile. It is a thing.

[Conventional technology]

Conventionally, in an automobile air conditioner, an evaporator of a refrigeration cycle is installed on the upstream side of a ventilation passage having an air intake port on one end side and an air outlet port to the vehicle interior on the other end side. A heater (heater core) that uses engine cooling water as a heat source is installed on the downstream side of the engine, and the temperature of air blown into the vehicle compartment is adjusted by adjusting the amount of heating by the heater. As the heating amount adjusting means, an air mix damper for adjusting the air flow rate of hot air passing through the heater and cold air bypassing it, or a hot water valve for adjusting the hot water flow rate to the heater is used.

By the way, according to the above configuration, the compressor of the refrigeration cycle always operates at the maximum discharge capacity simply by adjusting the opening degree of the air mix damper or the hot water valve. Therefore,
In spring and autumn, when the maximum cooling capacity is not required, there is a problem that the compressor driving power is consumed more than necessary.

For this reason, the applicant of the present invention previously disclosed in Japanese Patent Laid-Open No. 58-105818
In the publication, based on the set temperature, the vehicle interior temperature, the outside air temperature, etc., the required blown air temperature for maintaining and approaching the passenger compartment to the set temperature is calculated, and the refrigeration cycle of the refrigeration cycle is calculated according to the required blown air temperature. It has been proposed to change the discharge capacity of the compressor and thereby change the cooling capacity of the evaporator to control the temperature of air blown into the vehicle interior.

[Problems to be solved by the invention]

By the way, in the device described in the above publication, the discharge capacity of the compressor is determined by directly corresponding to the level of the required blown air temperature, but even with the same discharge capacity, the intake air temperature to the ventilation passage,
When an element related to the air-conditioning load such as the amount of air blow changes, the air temperature immediately after passing through the evaporator also changes, which makes it difficult to accurately control the vehicle interior temperature.

The present invention has been made in view of the above points, and an object of the present invention is to accurately and satisfactorily control the indoor temperature of an air conditioning target by controlling the discharge capacity of a compressor.

[Means for solving problems]

The present invention adopts the following technical means in order to achieve the above object.

That is, in the present invention, as shown in FIG. 1, (a) an air passage 10 having air inlets 36 and 37 at one end side and an air outlet 40 communicating with the room at the other end side; b) a blower 33 that sucks air from the air suction ports 36, 37 and blows the sucked air from the blowout port 40 through the ventilation passage 10, and (c) is provided in the ventilation passage 10 An evaporator 12 of the refrigeration cycle 11 for cooling the air in the ventilation passage 10, and (d) an air which is provided in a portion of the ventilation passage 10 on the air downstream side of the evaporator 12 and which has passed through the evaporator 12. A heater 35 for heating the heating device, (e) heating degree adjusting means 34, 60 for adjusting the degree of air heating in the heater 35, and (f) a first electrical device for driving the heating degree adjusting means 34, 60. A drive mechanism 42, and (g) is connected to the outlet side of the evaporator 12 in the refrigeration cycle 11 and changes the discharge capacity. Variable capacity mechanism
A variable capacity compressor 14 having 13; (h) a second electric drive mechanism 15 for driving the capacity variable mechanism 13; and (i) a detection means 17 for detecting the cooling degree To of the evaporator 12.
(J) The set temperature ts in the room and signals (tr, tam, tn, etc.) related to the air conditioning load in the room are input, and the room is brought close to the set temperature ts based on these input signals. Required blown air temperature calculation means 16 for calculating the required blown air temperature Tn for maintaining, (k) Required blown air temperature Tn calculated by the required blown air temperature calculation means 16 and detected by the detection means 17. A capacity control signal calculating means 18 for calculating a capacity control signal DT based on the evaporator cooling degree To, and (l) the necessary blowout air temperature Tn calculated by the necessary blowout air temperature calculating means 16 is preset. Determination means 70 for determining whether or not it is below a first set value Tnc, and (m) if this required means 70 determines that the required blown air temperature Tn is below the first set value Tnc , Degree of air heating in the heater 35 Is controlled to be substantially zero, and the capacity is increased so as to increase the cooling degree To of the evaporator 12 in accordance with the decrease in the required blown air temperature Tn. A first control means 72 for controlling the second electric drive mechanism 15 on the basis of a control signal DT, and (n) the required blown air temperature Tn at the judgment means 70 is lower than the first set value Tnc. If determined to be larger, the second control means 74 for controlling the first electric drive mechanism 42 so as to increase the air heating degree in the heater 35 in accordance with the rise in the required blown air temperature Tn, o) When the determination means 70 determines that the required blown air temperature Tn is higher than the first set value Tnc, the required blown air temperature Tn is higher than the first set value Tnc by a certain value. If the second set value Tnc1 or less, above the required blown air temperature Tn Cooling degree of the evaporator 12 in accordance with the
When To is reduced and the required outlet air temperature Tn is equal to or lower than the second set value Tnc1, the cooling degree To of the evaporator 12 is substantially minimized based on the capacity control signal DT. A third control means 76 for controlling the second electric drive mechanism 15 is provided.

Here, the heating degree adjusting means may be, for example, an air mix damper 34 that adjusts the ratio of warm air passing through the heater 35 and cold air bypassing the heater 35,
For example, a hot water valve 60 for adjusting the flow rate of hot water to the heater 35 may be used.

As the first electric drive mechanism 42, for example, a link
A servo motor or a diaphragm for driving the air mix damper 34 via 41 may be used, or for example, the hot water valve 60 may be driven by being controlled by the drive circuit 43.

The refrigeration cycle 11 has a known configuration including a condenser 20, a liquid receiver 21, an expansion valve 22 forming a pressure reducing device, etc. in addition to the variable capacity compressor 14 and the evaporator 12, and the compressor. Any material may be used as the material 14 as long as the discharge capacity can be continuously or discontinuously changed by the capacity varying mechanism 13.

The capacity varying mechanism 13 is, for example, Japanese Patent Laid-Open No. 58-1552.
As is known in Japanese Patent Publication No. 87, a compressor that continuously changes the discharge capacity of the compressor 14 by controlling the back pressure of the capacity adjusting member can be used.

As the second electric drive mechanism, for example, the solenoid valve 15
Including a, this solenoid valve 15a is installed in a bypass passage that connects the back pressure chamber of the capacity adjusting member and the refrigerant suction side of the compressor 14, and the back pressure chamber is placed on the refrigerant discharge side of the compressor 14. The pressure in the back pressure chamber is controlled by communicating and controlling the opening / closing of the solenoid valve 15a according to the magnitude of the duty ratio, thereby changing the position of the capacity adjusting member.

Further, as the detection means 17, for example, the air temperature To immediately after passing through the evaporator 12 is detected as the cooling degree of the evaporator 12, and a temperature sensor such as a thermistor can be used. As the degree of cooling of the evaporator 12, it is also possible to detect the evaporator fin surface temperature and the like, and in the case of this fin surface temperature, the detected temperature is corrected by the intake air temperature, the air flow rate, etc., if necessary. You may do it.

Required blown air temperature calculation means 16, capacity control signal calculation means 1
8, the determination means 70, the first control means 72, the second control means 74, and the third control means 76 are constituted by, for example, a microcomputer.

Of these, the required blown air temperature calculation means 16 receives the indoor set temperature ts set by the user, the indoor air temperature tr related to the indoor air conditioning load, the outside air temperature tam, the solar radiation amount tn ... Set temperature ts in the room based on the input signal
Can be configured to calculate a required blown air temperature Tn for approaching and maintaining the temperature.

Further, the capacity control signal calculating means 18 is configured to calculate the required blown air temperature.
The capacity control signal DT is calculated based on the evaporator cooling degree To detected by Tn and the detection means 17, and the capacity control signal DT has a larger capacity as the required blown air temperature Tn is lower, Further, the cooling degree To, for example, the capacity becomes larger as the detected temperature To of the air temperature immediately after passing through the evaporator becomes higher. The capacity control signal DT is specifically expressed by, for example, opening / closing the solenoid valve 15a as a duty ratio.

[Action]

According to the above technical means, the required blown air temperature calculating means 16
When the required blown air temperature Tn calculated by is less than or equal to the preset first set value Tnc, the first control means 72
Causes the degree of air heating in the heater 35 to be substantially zero.
The first electric drive mechanism 42 is controlled so that the second degree is determined based on the capacity control signal DT so that the cooling degree To of the evaporator 12 increases in accordance with the decrease in the required blown air temperature Tn. The electric drive mechanism 39 is controlled.

Here, the capacity control signal DT is the capacity control signal calculating means 18
Is calculated based on the required blown air temperature Tn and the evaporator cooling degree To detected by the detection means 17, the second electric drive mechanism 39 controlled on the basis of this DT It will be controlled based on not only the temperature Tn but also this Tn and the evaporator cooling degree To.

Therefore, even if the actual evaporator cooling degree To changes due to changes in the intake air temperature, air flow rate, etc. related to the air conditioning load, it becomes possible to set the compressor discharge capacity control corresponding to this, with good response. Thus, the temperature of the air blown into the room can be accurately controlled.

Further, when the required blown air temperature Tn is higher than the set value Tnc, the second control means 74 causes the first heating unit 74 to increase the air heating degree in accordance with the rise of the required blown air temperature Tn. The dynamic drive mechanism 42 is controlled. At the same time, the third control means 76 controls the required blown air temperature Tn.
Is a second set value T that is higher than the first set value Tnc by a certain value.
When nc1 or less, the second electric drive mechanism 15 is controlled based on the capacity control signal DT so that the cooling degree To of the evaporator 12 becomes smaller in accordance with the increase in the required blown air temperature Tn.
When the required blown air temperature Tn is equal to or higher than the second set value Tnc1, the second electric drive mechanism 15 is set based on the capacity control signal DT so that the cooling degree To of the evaporator 12 is substantially minimized.
Is controlled.

Thus, when the required blown air temperature Tn rises and reaches Tnc, the degree of air heating in the heater 35 starts to increase, but the cooling degree To at the start of this increase is not substantially the minimum, and Since it is slightly larger than the above, the following effects are achieved.

When the air heating degree of the heating degree adjusting means such as the air mix damper or the hot water valve is slightly increased from the state of 0, a large fluctuation of the blown air temperature occurs at the start of the increase. Therefore, at this time, an occupant in the vehicle compartment may feel uncomfortable due to a sudden change in the blowing temperature. However, even with the same blowout temperature fluctuation, the occupant is less likely to feel the blowout temperature when the blown air temperature into the vehicle interior is low and when it is high.

Therefore, as in the present invention, by increasing the cooling degree To at the start of the increase above a substantially minimum value,
The temperature of the air blown into the vehicle interior can be made lower than when the cooling degree To at the start of the increase is substantially minimum. As a result, it is possible to reduce the degree of discomfort that the blowout temperature variation gives to the occupant.

Further, even after the cooling degree To of the evaporator 12 is substantially minimized, the temperature of the air blown into the room can be accurately controlled in accordance with the degree of air heating in the heater 35.

〔The invention's effect〕

As described above, in the present invention, when the required outlet air temperature Tn rises to reach the first set value Tnc and the degree of air heating in the heater 35 starts to increase, the vehicle interior at the start of this increase Since it is possible to suppress fluctuations in the temperature of the air blown to the air, it is possible to perform a wide range of blown air temperature control without giving an occupant an uncomfortable feeling.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows a first embodiment in which the present invention is applied to an automobile air conditioner, and the variable displacement compressor 14 is driven by an automobile engine 31 via an electromagnetic clutch 30. Ventilation path 10
Is configured by connecting a case of a blower unit of a vehicle air conditioner, a case of a cooler unit, a case of a heater unit, etc., and one end side ( From the left end side in FIG. 2) to the other end side (right end side in FIG. 2), the inside / outside air switching door 32, the blower 33, the evaporator 12, the air mix tamper 34, and the heater are provided.
35 are arranged in sequence.

The inside / outside air switching door 32 introduces outside air from the outside of the vehicle when the outside air intake port 36 of the air passage 10 is opened, while the inside air intake port 37 of the air passage 10 opens the air in the passenger compartment 38. Recirculate in the air passage 10.

The blower 33 sucks air from the outside air suction port 36 or the inside air suction port 37 and sends it to the evaporator 12 of the refrigeration cycle. The airflow from the blower 33 is cooled by the latent heat of vaporization of the refrigerant in the evaporator 12 and is blown to the air mix damper 34 side as cold air. On the other hand, the gas refrigerant in the evaporator 12 that has exchanged heat with the air flow from the blower 33 and is evaporated is sent to the suction side of the variable capacity compressor 14. The compressor 14 is operatively connected to a vehicle engine 31 via an electromagnetic clutch 30 that is excited by a drive circuit 39, and the engine is excited by the electromagnetic clutch 30.
The gas refrigerant driven by 31 and sent from the evaporator 12 is compressed into a high-pressure temperature refrigerant, which is cooled in the condenser 20 and liquefied (condensed), and this liquid refrigerant is stored in the liquid receiver 21 and then. The liquid refrigerant is decompressed and expanded through the expansion valve 22 and sent again to the evaporator 12 as a low pressure and low temperature atomized refrigerant. The electromagnetic clutch
When 30 is in the de-energized state, the compressor 14 is disconnected from the engine 31 and stopped.

The heater 35 receives high-temperature cooling water (warm water) from the engine 31 and warms the cooling air flow passing through the evaporator 12 into warm air, and the air mix damper 34 has its opening tar.
The air flow rate ratio between the warm air passing through the heater 35 and the cold air bypassing the heater 35 is adjusted by.

Then, in the air passage on the downstream side of the heater 35, the warm air that has passed through the heater 35 and the cold air that bypassed the sides of the heater 35 are mixed, and the air having a predetermined temperature corresponding to the opening degree tar of the damper 34 is mixed. Then, it blows out from the outlet 40 into the passenger compartment 38. As is well known, the air outlet 40 includes an upper air outlet for cooling ventilation, a foot air outlet for heating, a defroster air outlet, and the like.

If the opening tar of the air mix damper 34 is zero, the evaporator 1
All of the cool air from 2 bypasses the heater 35 and blows out 4
The maximum cooling capacity is exerted by directly blowing from 0 into the passenger compartment 38, while the fully open state and the entire cold air from the evaporator 12 is heated by the heater 35, so the maximum heating capacity is exerted. To be done.

The air mix damper 34 is driven by an electric drive mechanism 42 via a link 41.
As the 42, it is possible to use a negative pressure diaphragm or the like in which the magnitude of the negative pressure is adjusted by a well-known servo motor or a solenoid valve and which is displaced according to the large base of the negative pressure. Is controlled. Reference numeral 44 denotes a control circuit, an input circuit 45 to which detection signals of various sensors to be described later are input, a microcomputer 46 that performs predetermined arithmetic processing based on the input signal from the input circuit 45, and the microcomputer 46. Based on the output signal, the device 15,3
It has drive circuits 19, 39 and 43 for controlling the energization to 0 and 42.

The input circuit 45 has a built-in AD converter for converting an analog signal into a digital signal, and the drive circuits 19, 39, 43.
Incorporates a transistor switch circuit for driving a load, a relay circuit, and the like.

On the other hand, the microcomputer 46 is formed by a digital computer including a single-chip LSI,
The microcomputer 46 receives a constant voltage from a constant voltage circuit (not shown) and is placed in a ready state for operation.
In this case, the constant voltage circuit receives a DC voltage from a vehicle-mounted DC power source (battery) and generates the constant voltage in response to closing of an ignition switch (not shown) of the automobile engine 31. The microcomputer 46 includes a central processing unit (hereinafter referred to as CPU), a memory (ROM, PAM), a clock circuit, etc., and these CPU, memory (ROM, PA).
M), the clock circuits are connected to each other via a bus line. The memory (RAM) of the microcomputer 46 receives each digital signal from the input circuit 45 and temporarily stores it, and selectively gives each of these signals to the CPU. The clock circuit of the microcomputer 46 cooperates with the crystal oscillator to allow execution of a predetermined control program in the microcomputer 46.

In the memory (ROM) of the microcomputer 46, the above-mentioned predetermined control program is stored in advance in order to execute the arithmetic processing described later in the microcomputer 46.

On the other hand, in the present embodiment, as the physical quantity related to the air conditioning heat load in the vehicle interior, the vehicle interior temperature tr, the outside air temperature tam, the amount of solar radiation tn into the vehicle interior, the opening tar of the air mix damper 34, the flow of the heater 35. The inlet water temperature tw is the inside air temperature sensor 50 and the outside air temperature sensor, respectively.
51, the solar radiation sensor 52, the opening sensor 53, and the water temperature sensor 54, and the detection signals of these sensors are all input to the input circuit 45.

As a physical quantity related to the cooling degree of the evaporator 12, the temperature To immediately after passing through the evaporator is a temperature sensor composed of a thermistor.
The signal is detected by 17, and the detection signal is input to the input circuit 45.

Further, in this example, the refrigerant pressure in the outlet refrigerant pipe of the evaporator 12
Po is detected by the pressure sensor 55, and the detection signal is input to the input circuit 45.

Further, the temperature setter 56 sets the desired temperature for air conditioning in the passenger compartment (that is, the set temperature ts) by the operation of the occupant, and usually comprises a variable resistor. It The temperature setting device 56 is provided on an air conditioning control panel (not shown) installed near the instrument panel in the vehicle compartment.

Next, the operation of the first embodiment will be described with reference to FIGS. 3 and 4. FIG. 3 is a flowchart showing a control program by the microcomputer 46. First, the computer 46 receives a constant voltage from the constant voltage circuit, is in a ready state for operation, and starts execution of arithmetic processing in step 100. To do. Next, at step 101, the air temperature To immediately after passing through the evaporator, the refrigerant evaporation pressure Po of the evaporator 12, the vehicle interior air temperature tr, the outside air temperature tam, the vehicle interior solar radiation amount tn, the damper opening tar, the heater inlet. The water temperature tw and the passenger compartment set temperature ts are input,
It is temporarily stored in the memory (RAM) of the computer 46. Next, at step 102, the required blown air temperature Tn for maintaining the vehicle interior at the set temperature ts is calculated. Where Tn
Is given as Tn = Ks.ts-Kr.tr-Kam.tam-Kn.tn + C. The gains Ks, Kr, Kam, Kn and the constant C are stored in advance in the memory (ROM). In this embodiment, step 102 constitutes the required blown air temperature calculating means.

Next, at step 103, the To is the first set temperature Tc1 (about 3
C degree)). Here, Tc1 is preset and stored in the memory (ROM) of the computer 46. Then, if To ≦ Tc1 by the comparison, it is determined that the cooling capacity of the evaporator 12 is excessive, and the process proceeds to step 104, and a command signal for disconnecting the electromagnetic clutch 30 is output to the clutch drive circuit 39. . Based on this, the clutch drive circuit 39
Puts the clutch 30 in the disengaged state (compressor stopped state) and the evaporator
Prevents 12 frosts. If To> Tc1 in step 103, the process proceeds to step 105, in which Po is compared with a set pressure Pc1 (about 0.5 kg / cm ² ) prestored in the memory (ROM) of the computer 46, and Po ≦ Pc
If 1, it is determined that the refrigerant is in shortage, step 1
Proceeding to 04, the clutch 30 is disengaged in the same manner as above. If Po> Pc1 in step 105,
It is determined that the refrigerant amount is normal, the process proceeds to step 106,
It is determined whether the temperature control in the vehicle compartment is performed by the capacity control of the compressor 14 or the opening degree adjustment of the air mix damper 34.

That is, in step 106, the required blown air temperature Tn is compared with the control determination temperature Tnc (which is a preset setting value and stored in the memory (ROM)), and Tn ≦ Tnc
If it is, the process proceeds to step 107, and the target temperature Ts of the air temperature immediately after passing through the evaporator is set in accordance with Tn as shown in FIG.
It is determined as a function f ₁ (Tn) that is directly proportional to Tn.
Here, in FIG. 4, the horizontal axis shows the required blown air temperature Tn, and the vertical axis shows the target temperature Ts and the air mix damper opening degree.
It is a tar. In this embodiment, step 106 constitutes the judgment means.

Next, in step 108, the target value Ps of the refrigerant evaporation pressure of the evaporator 12 is set as Ps = f ₂ (Ts-To). That is,
This target pressure Ps is expressed as a function of the difference between the target temperature Ts and the actual air temperature To immediately after passing through the evaporator.

More specifically, the relation of Ps is expressed by the following equation.

ET _P = Ts-To SET _P = SET _P-1 + ET _P In the above equation, Kp and Ti are constants stored in the memory (ROM).

As can be understood from the above equation, the target pressure Ps is obtained by the proportional integral control (PI control) method.

Next, the routine proceeds to step 109, where the on / off duty ratio DT of the solenoid valve 15a of the electric drive means 15 for controlling the variable capacity mechanism 13 is calculated based on Ps and Po. More specifically, the calculation of the duty ratio DT is expressed by the following equation.

EPn = Ps-Po SEPn = SEP _n-1 + EPn In the above equation, Kp · Ti and Td are constants stored in the memory (ROM). As understood from the above equation, the duty ratio DT is obtained by the method of proportional-plus-integral-derivative control (PID control). In this embodiment, step 109 constitutes the capacity control signal calculating means.

Next, at step 110, a pulse signal for turning on / off the solenoid valve 15a based on the duty ratio DT is output to the solenoid valve drive circuit 19. Based on this, the drive circuit 19 turns on / off the solenoid valve 15a to change the refrigerant pressure applied to the capacity adjusting member of the capacity varying mechanism 13 of the compressor 14 to change the discharge capacity. As a result, the cooling capacity of the evaporator 12 changes, and the air temperature To immediately after passing through the evaporator changes, but at this time, since the opening tar of the air mix damper 34 is maintained at zero, heating is performed. The heating amount by the device 35 is zero. Therefore, by changing the cooling capacity of the evaporator 12 by performing the capacity control as described above, the temperature of the air blown into the vehicle interior changes, and the vehicle interior temperature becomes the set temperature ts. Can be controlled. In this embodiment, step 110 constitutes the first control means.

In step 106, if Tn> Tnc, the process proceeds to steps 111 to 112, and in addition to the compressor capacity control, the heating amount of the heater 35 is adjusted by adjusting the opening degree of the air mix damper 34. In this case, as the capacity control method, the target temperature Ts of the air temperature immediately after passing through the evaporator is determined from the required outlet air temperature Tn, and the capacity control is performed so that the detected value To of the evaporator outlet air temperature matches the above Ts. However, if the required outlet air temperature Tn is equal to or lower than another determination temperature Tnc1 (see FIG. 4) which is higher than the control determination temperature Tnc by a certain value, the target temperature Ts is set to the required outlet air temperature. It is determined as a function f1 (Tn) that rises according to the rise of Tn. If the required blown air temperature Tn is equal to or higher than the determination temperature Tnc1, the state of the minimum capacity is maintained.

Here, in step 112, the calculated target damper opening tars is calculated by the following equation tars = 100 × (Tn−Tnc)
Expressed as / (tw-Tnc-Co).

Here, Co is a constant preset in the memory (ROM).

Then, the calculated target damper opening tars is compared with the actual air mix damper opening tar, and a command signal is given to the electric drive mechanism 42 via the drive circuit 43 according to the result. In this case, hysteresis can be set in the comparison process, and a specific example thereof is illustrated in JP-A-57-77659. In this embodiment, step 111 and step 112 constitute the second control means.

The above-mentioned computer program is repeatedly executed, so that, as described above, when the required blowout air temperature Tn is equal to or lower than the determination temperature Tnc, the opening degree of the air mix damper 34 is set to 0, By adjusting the discharge capacity of the compressor 14 according to the rise of the required blown air temperature Tn, the blown air temperature into the passenger compartment is adjusted. In addition,
The discharge capacity of the compressor 14 when the Tn is the determination temperature Tnc is not the minimum capacity, but is slightly larger than the minimum capacity.

In the range where the required blown air temperature Tn is higher than the judgment temperature Tnc, the opening degree of the air mix damper 34 is set to the required blown air temperature.
The temperature of the air blown into the passenger compartment is adjusted by increasing it as Tn rises. On the other hand, the discharge capacity of the compressor 14 is
As the required blown air temperature Tn rises, it further decreases, and becomes the minimum capacity at Tn = Tnc1. And Tn> Tn
In c1, the discharge volume should be the minimum volume.

According to this, when the required outlet air temperature Tn rises and reaches Tnc, the air mix damper 34 starts to open, but since the discharge capacity at the beginning of opening is not the minimum capacity but a slightly larger capacity than this. The following effects are achieved.

If the air mix damper is slightly opened from the state where the opening degree is 0, a relatively large variation in the temperature of the blown air occurs at this time. Therefore, at this time, an occupant in the vehicle compartment may feel uncomfortable due to a sudden change in the blowing temperature. However, even with the same blowout temperature fluctuation, the occupant is less likely to feel the blowout temperature when the blown air temperature into the vehicle interior is low and when it is high.

Therefore, as in the present embodiment, by making the discharge capacity of the compressor 14 at the beginning of opening the air mix damper 34 slightly larger than the minimum capacity, when the capacity at the beginning of opening is the minimum capacity. In comparison, the temperature of air blown into the vehicle interior can be lowered. As a result, it is possible to reduce the degree of discomfort that the blowout temperature variation gives to the occupant.

Further, by driving with the discharge capacity of the compressor 14 when the required blown air temperature Tn is higher than the determination temperature Tnc1, although some compressor driving power is required in the heating area, it depends on the evaporator 12. A dehumidifying action can be obtained.

FIG. 5 shows the second embodiment, and step 108 in FIG. 3 is eliminated, and the duty ratio DT is directly obtained as a function of the difference between the target temperature Ts and the actual temperature To in step 109a. It is a thing.

FIG. 6 shows a third embodiment. In this example, the air mix damper 34 shown in FIG. 2 is abolished, and instead, a heater 35 is installed over the entire cross-sectional area of the air duct 10. Thus, all the air passing through the evaporator is allowed to pass through the heater 35. Then, the flow rate of hot water to the heater 35 is adjusted by the hot water valve 60, and the heating amount by the heater 35 is adjusted.

The hot water valve 60 is driven by the electric drive mechanism 42 controlled by the drive circuit 43. Position sensor 53 in this example
a is for detecting the opening degree twr of the hot water valve 60.

In this example, by changing the damper opening adjustment of step 112 in the control flow of FIG. 3 to the opening adjustment of the hot water valve 60, the damper opening adjustment in the control characteristic diagram of FIG. The other points are the same as those in the above-described embodiment except that the adjustment is changed.

As in the present embodiment, even in the case of adjusting the heating degree of the heater 35 by adjusting the opening degree of the hot water valve 60,
Since a relatively large change in the blown air temperature occurs at the beginning of opening the hot water valve 60, the compressor at the beginning of opening the hot water valve 60
By setting the discharge capacity of 14 to be slightly larger than the minimum capacity, the same effect as that of the above-described embodiment can be obtained.

Although each of the above-described embodiments has been described with respect to an air conditioner for a vehicle having a heating function by the heater 35, the present invention can be applied to an air conditioner for a vehicle without the heater 35.

Further, it is needless to say that the present invention can be widely applied not only to automobiles but also to air conditioners for other purposes.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing the basic configuration of the present invention, FIG. 2 is an overall configuration diagram showing the configuration of the first embodiment, and FIG.
4 is a control characteristic diagram of the first embodiment, FIG. 5 is a flowchart showing the second embodiment, and FIG. 6 is a control characteristic diagram showing the third embodiment. 10 …… Ventilation path, 11 …… Refrigeration cycle, 12 …… Evaporator, 13…
… Variable capacity mechanism, 14 …… Variable capacity compressor, 15 …… Electric drive means, 16 …… First control means, 17 …… Detecting means, 18 ……
Second control means, 19 ... Drive circuit.

Claims (1)

[Claims] 1. An air passage having (a) an air intake port at one end and an air outlet connected to the room at the other end; and (b) air is sucked from the air intake port A blower that blows out air from the outlet through the ventilation passage; (c) an evaporator of a refrigeration cycle that is provided in the ventilation passage and cools air in the ventilation passage; and (d) inside the ventilation passage. (E) a heating degree adjusting means for adjusting the degree of air heating in the heater, the heater being provided at a downstream side of the evaporator in the air, and heating the air passing through the evaporator; ) A first electric drive mechanism for driving the heating degree adjusting means, and (g) a variable capacity type compression mechanism having a capacity variable mechanism connected to the outlet side of the evaporator in the refrigeration cycle and for changing the discharge capacity. And (h) drive the variable capacity mechanism. A moving second electric drive mechanism, (i) a detecting means for detecting the degree of cooling of the evaporator, and (j) a signal relating to the set temperature in the room and the air conditioning load in the room, Based on the input signal
A necessary blow-out air temperature calculating means for calculating a necessary blow-out air temperature for maintaining the room close to the set temperature, and (k) the necessary blow-out air temperature calculated by the necessary blow-out air temperature calculating means and the detecting means. A capacity control signal calculating means for calculating a capacity control signal based on the evaporator cooling degree detected by: (l) a required blown air temperature calculated by the required blown air temperature calculating means, Determination means for determining whether or not it is less than or equal to the set value of 1, and (m) when the required blown air temperature is determined to be less than or equal to the first set value in this determination means, In order to make the air heating degree substantially zero, the first
And controlling the second electric drive mechanism based on the capacity control signal so as to increase the degree of cooling of the evaporator in accordance with the decrease in the required blown air temperature. First control means, and (n) when the determination means determines that the required outlet air temperature is higher than the first set value, the air in the heater is increased according to the increase in the required outlet air temperature. Second control means for controlling the first electric drive mechanism so as to increase the heating degree; and (o) the determination means determines that the required blown air temperature is higher than the first set value. When the required blown air temperature is equal to or lower than the second set value which is higher than the first set value by a constant value, the cooling degree of the evaporator is decreased according to the rise of the required blown air temperature. , The required blown air When the degree is equal to or higher than the second set value, a third control for controlling the second electric drive mechanism based on the capacity control signal so as to substantially minimize the degree of cooling of the evaporator. A refrigeration cycle control device for air conditioning, comprising: