JP2995940B2 - Air conditioning controller for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner for a vehicle, and more particularly to an air conditioner for a vehicle employing a variable displacement compressor as a refrigerant compression means of a refrigeration cycle.

[0002]

2. Description of the Related Art Conventionally, in a vehicle air conditioner of this type, the capacity of a variable displacement compressor is controlled by the same displacement control mechanism so as to be inversely proportional to a flow control current flowing into a displacement control mechanism attached to the compressor. When the heat load is large, the control current is determined to be reduced based on the PI control equation so as to decrease the actual outlet temperature of the evaporator toward the target outlet temperature. Is smaller, the control current is increased based on the PI control equation so as to raise the actual outlet temperature of the evaporator toward the target outlet temperature, and economy control is performed in accordance with the determined control current. For example, when the cooling capacity is required as in the case of the above, the economy control is released and the control is performed so as to lower the outlet temperature of the evaporator.

[0003]

By the way, in such a configuration, when the economy control is canceled due to the necessity of dehumidification or the like, the capacity control mechanism is increased to increase the cooling capacity with a change in the target outlet temperature of the evaporator. Is controlled so as to gradually decrease the control current, but the rate of decrease of the control current is kept low due to the limitation of the magnitudes of the proportional gain and the integral gain of the PI control arithmetic expression. Therefore, for example, in a non-control region where the capacity of the compressor is maintained at a minimum, the capacity of the compressor is maintained at a minimum despite a change in the control current, and as a result, the cooling capacity is rapidly reduced. Therefore, there is a problem that an appropriate dehumidifying effect cannot be secured. Therefore, the present invention, in order to deal with such a problem, in the vehicle air conditioning control device, even when switching from the economy mode to another mode by effectively utilizing the function of the variable displacement compressor, Immediately after the switching, the cooling capacity is properly exhibited with good responsiveness.

[0004]

In order to solve the above-mentioned problems, a structural feature of the present invention is, as exemplified in FIG. 1, that the interior of the vehicle cabin is cooled by an evaporator according to the capacity of a variable displacement compressor. Temperature control means 1 for controlling the temperature of the blown air flow toward the required blow temperature, required blow temperature determining means 2 for determining the required blow temperature in accordance with the set temperature and the internal temperature, and whether or not the economy mode is set. Mode determining means 3 for determining whether or not the economy mode is set, the target outlet temperature of the evaporator is determined as the first target outlet temperature according to the required blow-out temperature when determining the economy mode, and when determining that the economy mode is not set, A target outlet temperature determining means for determining a constant outlet temperature as a second target outlet temperature; The capacity is PI-controlled to maintain the outlet temperature at the first target outlet temperature, and when it is determined that the vehicle is not in the economy mode, the actual outlet temperature of the evaporator is maintained at the second target outlet temperature immediately thereafter. In order to maintain the actual outlet temperature at the second target outlet temperature, control is performed so as to maximize the capacity in order to maintain the actual outlet temperature at the second target outlet temperature. It is in. I did it.

[0005]

When the required outlet temperature determining means determines the required outlet temperature of the blown airflow into the vehicle interior according to the set temperature and the internal temperature, the target outlet temperature is determined when the mode determining means determines the economy mode. Means 4 determines the target outlet temperature of the evaporator as the first target outlet temperature according to the required blow-out temperature, and the capacity control means 5 maintains the actual outlet temperature of the evaporator at the first target outlet temperature. Therefore, the capacity is controlled by PI, and the blow-out temperature control means 1 controls the temperature of the blow-out air flow to the required blow-out temperature via the compressor and the evaporator according to the control capacity. Also, the mode determining means 3
When it is determined that the vehicle is not in the economy mode, the target outlet temperature determining means 4 determines the constant outlet temperature of the evaporator as the second target outlet temperature, and immediately after the capacity control means 5 determines that the vehicle is not in the economy mode, Control is performed so as to maximize the capacity so as to maintain the actual outlet temperature at the second target outlet temperature, and thereafter, the actual outlet temperature is reduced to the second target outlet temperature.
PI control of the capacity to maintain the target outlet temperature, and
The blowout temperature control means 1 controls the temperature of the blown air flow through the evaporator according to the change of the compressor to the maximum capacity and the subsequent change of the same capacity.

[0006]

As described above, by effectively utilizing the change in capacity of the variable displacement compressor as described above, an appropriate cooling capacity can be secured with good responsiveness immediately after switching from the economy mode to another mode. The function as the air-conditioning control device in the other mode can be sufficiently exhibited.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing one embodiment of the present invention applied to a vehicle air conditioner control apparatus. This air conditioning control device is provided with an air duct 10, and inside the air duct 10,
From the upstream to the downstream, a blower 20, an evaporator 30, an air mix damper 40, and a heater core 50 are sequentially arranged. The blower 20 has a blower motor 2
The airflow is driven into the air duct 10 by being driven by Oa, and is blown into the vehicle interior of the vehicle through the evaporator 30, the air mix damper 40, and the heater core 50. The evaporator 30 constitutes a cooling means of the refrigeration cycle R of the air conditioner control device.
The air flow from the blower 20 is cooled according to the evaporating action of the inflow refrigerant, and the refrigerant is returned to the compressor 60 through the pipe P1.

The air mix damper 40 allows the cooling air flow from the evaporator 30 to flow into the heater core 50 and the remaining cooling air flow directly toward the outlet of the air duct 10 according to the actual opening degree. The heater core 50 heats the incoming cooling air flow and causes it to flow toward the outlet. Also, the refrigeration cycle R
The compressor 60 includes a variable displacement compressor 60. The compressor 60 is connected to an input shaft of an electromagnetic clutch 60a attached to the compressor 60 via a V-belt mechanism 80.
Output shaft. The electromagnetic clutch 60 a transmits the output from the engine 70 to the compressor 60 via the V-belt mechanism 80 by its selective engagement.

The compressor 60 has a displacement control mechanism 60b, which controls the displacement of the compressor 60 in inverse proportion to the inflow control current. Thus, the compressor 60 has a capacity control mechanism 60.
The refrigerant from the pipe P1 is sucked and compressed according to the capacity based on the control by b, and flows into the condenser 90 through the pipe P2 as a high-temperature and high-pressure compressed refrigerant. The condenser 90 condenses the inflowing compressed refrigerant under the air-cooling operation of the air-cooling fan 90a, and condenses the refrigerant as a condensed refrigerant through the pipe P3 to the receiver 1.
00. The receiver 100 separates the inflow refrigerant into gas and liquid and makes the liquid phase component flow into the expansion valve 110 through the pipe P4 as a circulating refrigerant. The expansion valve 110 expands the circulating refrigerant from the pipe P4 according to the detection result of the refrigerant temperature in the pipe P1 by the temperature sensing element 110a, and
Through the evaporator 30 as a low-temperature and low-pressure refrigerant.

Next, the electric circuit configuration of the air conditioner will be described. The operation switch S1 is operated when operating the air conditioner to generate an operation signal.
The economy switch S2 is operated when the air-conditioning control device is placed in economy control, and generates an economy control command signal. The dehumidification switch S3 is operated when the air-conditioning control device is set to the dehumidification control, and generates a dehumidification command signal. The temperature setting device 130 generates a desired temperature in the cabin of the vehicle as a set temperature signal. The internal temperature sensor 140
An actual temperature in the vehicle compartment is detected and generated as an internal temperature detection signal. The outside air temperature sensor 150 generates the actual temperature of the outside air of the vehicle as an outside air temperature detection signal.

The solar radiation sensor 160 detects the amount of solar radiation incident on the vehicle interior, and generates it as a solar radiation detection signal. The outlet temperature sensor 170 detects the actual temperature at the outlet of the evaporator 120 and generates the detected temperature as an outlet temperature detection signal. Water temperature sensor 1
80 detects the actual temperature of the cooling water of the cooling system of the engine 70 and generates it as a water temperature detection signal. AD converter 1
Reference numeral 90 denotes a set temperature signal from the temperature setter 130, an inside air temperature detection signal from the inside air temperature sensor 140, and an outside air temperature sensor 150
From the outside temperature, the insolation detection signal from the insolation sensor 160, the exit temperature detection signal from the exit temperature sensor 170, and the water temperature detection signal from the water temperature sensor 180. Generated as digital signals representing volume, outlet temperature, and water temperature, respectively.

The microcomputer 200 executes the computer program according to the flowchart shown in FIG.
Executed in cooperation with the operation switch S1, the economy switch S2, the dehumidification switch S3, and the AD converter 190,
During this execution, arithmetic processing necessary to drive and control each of the drive circuits 210, 220 and 230 connected to the blower motor 20a, the electromagnetic clutch 60a and the capacity control mechanism 60b and the servomotor 240 connected to the air mix damper 40 is performed. . However, the computer program is stored in the ROM of the microcomputer 200 in advance. Note that the microcomputer 200
The vehicle operates by receiving power from a battery B via an ignition switch IG of the vehicle, and starts executing a computer program in response to an operation signal from an operation switch S1.

In this embodiment configured as described above,
When the ignition switch IG is closed, the vehicle is brought into a running state with the engine 70 started and the microcomputer 200 is brought into an operating state. When an operation signal is generated from the operation switch S1, the microcomputer 200 starts executing the computer program in step 300 of the flowchart of FIG. 3, and performs initialization processing in step 310. Then
The microcomputer 200 determines in step 320
Each value of the digital signal (hereinafter, the set temperature Tset, the inside temperature Tr, and the outside temperature T) representing the set temperature, the inside temperature, the outside temperature, and the amount of solar radiation from the A / D converter 190 based on the following Expression 1
am and the amount of solar radiation ST), the required blowing temperature Tao of the blowing airflow into the vehicle compartment is calculated.

## EQU1 ## Tao = Kset · Tset + Kr · Tr + K
am · Tam + Kst · ST + C where Kset, Kr, Kam, K
“st” represents a gain, and “C” represents a constant. Equation 1 is stored in the ROM of the microcomputer 200 in advance.

After that, the microcomputer 200
At step 330, a blower output signal required for driving the blower 20 is generated, and at step 340, a clutch output signal required for engaging the electromagnetic clutch 60a is generated. Then, the blower 20 is driven by the drive circuit 210 by the blower motor 20 a in response to the blower output signal from the microcomputer 200, introduces airflow into the air duct 10, and blows air toward the evaporator 30. Further, the electromagnetic clutch 60a is
Driven by the drive circuit 220 in response to the clutch output signal from 0 to engage and transmit the output from the engine 70 to the compressor 60.

For this reason, the compressor 60 sucks and compresses the refrigerant from the evaporator 30 through the pipe P1 at its actual capacity, and flows the refrigerant into the condenser 90 through the pipe P2 as a high-temperature and high-pressure compressed refrigerant. Next, the condenser 90 condenses the inflowing compressed refrigerant under the air cooling action of the air-cooling fan 90a and converts the compressed refrigerant into a condensed refrigerant.
When the gas flows into the pipe P4, the receiver 100 separates the flowing condensed refrigerant into gas and liquid, and uses the liquid phase component as a circulating refrigerant.
Through the expansion valve 110. Then, when the expansion valve 110 expands the inflow refrigerant and flows into the evaporator 30 as the expansion refrigerant, the evaporator 30 cools the airflow from the blower 20 in accordance with the inflow refrigerant and sends the airflow to the air mix damper 40. Flow toward. Then, this cooling air flow flows into the heater core 50 according to the actual opening of the air mix damper 40, is heated and flows toward the outlet, and the remaining cooling air flow flows toward the outlet. To mix with the heated air stream and blow out into the cabin.

After the arithmetic processing in step 340, the microcomputer 200 proceeds to the next step 3
At 50, it is determined whether the air-conditioning control device is in the economy mode. At this stage, if an economy control command signal has been generated from the economy switch S2, the microcomputer 200 proceeds to step 350
Is determined to be "YES", and in the next step 350a,
Data representing the relationship between the target outlet temperature Teo at the outlet of the evaporator 30 and the required outlet temperature Tao in the economy mode (see FIG. 4A) (hereinafter referred to as Teo-T).
ao data), the target outlet temperature Teo is determined in accordance with the required outlet temperature Tao in step 340. However, the Teo-Tao data is stored in the ROM of the microcomputer 200 in advance.

Next, the microcomputer 200
At step 360, the A / D converter 1
90 (hereinafter referred to as the outlet temperature T).
e) and the target outlet temperature T in step 350a
The deviation En is calculated according to eo.

## EQU2 ## En = Te-Teo After that, the microcomputer 200 executes the step 3
At 60, based on the following equation (3), the capacity control mechanism 6 according to the previous control current Inp and the previous difference Enp to the capacity control mechanism 60b at step 380a.
The current control current In to 0b is calculated.

In = Inp−Kp {En−Enp + (En / Ti)} where Expression 3 represents a PI control operation expression, and is stored in advance in the ROM of the microcomputer 200 together with Expression 2. In equation (3), the symbol Kp represents a proportional gain. The symbol Ti represents a sampling constant.

When the arithmetic processing in step 360 is completed as described above, the microcomputer 200
In the next step 380, the control current In in step 360 is generated as a current output signal. Then, the drive circuit 230 controls the inflow control current to the capacity control mechanism 60b toward the control current In in step 360 in response to the current output signal from the microcomputer 200. Therefore, the displacement control mechanism 60b controls the displacement of the compressor 70 so as to be inversely proportional to the inflow control current In. This means that the discharge amount of the compressed refrigerant from the compressor 60 is regulated by the control capacity of the compressor 70.

After the calculation processing in step 380, the microcomputer 200 sets the control current In and the deviation En in step 360 to the control current Inp and the deviation Enp of the previous time in the next step 380a. Then, the microcomputer 200 determines the value of the water temperature digital signal from the A / D converter 190 (hereinafter, water temperature Tw) based on the following equation 4 in the opening degree calculation processing routine 390.
), The value of the outlet temperature digital signal (hereinafter, the outlet temperature T
e) and the target opening degree SW of the air mix damper 40 according to the required blowing temperature Tao in step 340.
Is calculated.

## EQU4 ## SW = (Tao-Te) / (Tw-Te) Thereafter, the microcomputer 200 generates the target opening SW as an opening output signal in the opening calculation routine 390. Then, the servo motor 240
In response to the opening output signal from the microcomputer 200, the air mix damper 40 is driven so that its actual opening matches the target opening SW while ensuring the target outlet temperature Teo in step 350a. . This allows
The air-conditioning control under the economy mode is performed in step 35.
The target outlet temperature Teo at 0a and the required outlet temperature Tao at step 340 are realized. In addition,
Equation 4 is stored in the ROM of the microcomputer 200 in advance.

In such an economy control state,
If the economy control command signal from the economy switch S2 is extinguished and the dehumidification command signal is generated from the dehumidification switch S3, when the computer program proceeds to step 350, the microcomputer 200 returns "NO" based on the dehumidification command signal. In the next step 350b, the target outlet temperature Teo is set to Teo = 1. At this stage, if the set in step 350b is the first one,
0 is determined to be immediately after the release of the economy mode, and in the next step 370, “YES” is determined, and
At 70a, the control current In and the deviation En are set to In = 0 and E
Set n = 0.

After that, the microcomputer 200
In step 380, when control current In = 0 is generated as a current output signal, drive circuit 230 controls the inflow control current to capacity control mechanism 60b in response to the current output signal from microcomputer 200 in step 370a. Control is performed so that the current In = 0. Therefore, the capacity control mechanism 60b controls the compressor 70 to maximize the capacity according to the inflow control current In = 0. This means that the discharge amount of the compressed refrigerant from the compressor 60 increases to the maximum amount according to the maximum capacity of the compressor 70. As a result, the amount of refrigerant flowing from the expansion valve 110 to the evaporator 30 is also maximized.

After the arithmetic processing in step 370a as described above, the microcomputer 200
At 80a, the control current In = 0 and the deviation En = 0 at step 370a are set to Inp and Enp, respectively, and at the next opening degree calculation processing routine 390, the control signal from the AD converter 190 is obtained based on the equation (4). Water temperature Tw and outlet temperature Te
And the required blowing temperature Tao in step 340.
Is calculated according to the target opening degree SW of the air mix damper 40. Thereafter, the microcomputer 200 generates the target opening degree SW as an opening degree output signal in the opening degree arithmetic processing routine 390. Then, the servo motor 24
0 changes the air mix damper 40 in response to the opening output signal from the microcomputer 200 and changes the actual opening thereof to the target opening SW while maintaining the target outlet temperature Teo = 1.
Drive to match. As a result, the air conditioning control in the dehumidification mode is started so as to realize the target outlet temperature Teo = 1 and the required blowing temperature Tao in step 340.

In such a state, when the computer program proceeds to step 370 through step 350b, the microcomputer 200 determines that the elapse immediately after the release of the economy mode has been completed based on the fact that the setting in step 350b is not the first time. Determine "NO",
In step 360, the A / D converter 190 based on the equation (2)
The deviation En is calculated in accordance with the outlet temperature Te from step (1) and the target outlet temperature Teo = 1 in step 350b. After that,
In step 360, the microcomputer 200 determines the deviation En and step 380a based on the equation (3).
At the previous control current Inp = 0 and the previous deviation En
The current control current In is calculated according to p = 0.

When the arithmetic processing in step 360 is completed as described above, the microcomputer 200
In step 380, the control current In in step 360 is generated as a current output signal. Then, the drive circuit 230 controls the inflow control current to the capacity control mechanism 60b toward the control current In in step 360 in response to the current output signal from the microcomputer 200. Therefore, the displacement control mechanism 60b controls the displacement of the compressor 70 so as to be inversely proportional to the inflow control current In.
This means that the discharge amount of the compressed refrigerant from the compressor 60 is regulated by the control capacity of the compressor 70.

Thus, the microcomputer 200
However, in the next step 380a, the control current In and the deviation En in step 360
And the deviation Enp. Then, the microcomputer 200 calculates the water temperature Tw from the A / D converter 190 based on Equation 4 in the opening degree calculation routine 390,
The target opening degree SW of the air mix damper 40 is calculated according to the required blowing temperature Tao in step 3400 and the target outlet temperature Teo = 1 in step 350b.
Thereafter, the microcomputer 200 generates the target opening degree SW as an opening degree output signal in the opening degree arithmetic processing routine 390. Then, the servo motor 240
In response to the opening output signal from the microcomputer 200, the air mix damper 40 is driven so that its actual opening matches the target opening SW while ensuring the target outlet temperature Teo = 1. As a result, the air conditioning control in the dehumidification mode is performed with the target outlet temperature Teo = 1 and the step 3
It continues to achieve the required blowing temperature Tao at 40. Thereafter, the control in the dehumidification mode as described above is maintained on the premise that the determination of “NO” in Step 370 is repeated.

As described above, in the present embodiment, in the economy mode, the Teo-T shown in FIG.
The control current In is determined through arithmetic processing in step 360 so that the actual outlet temperature Te approaches the target outlet temperature Teo determined based on the ao data.
, The capacity of the compressor 60 is controlled as shown by a characteristic curve L shown in FIG. In such a state, when the mode is switched from the economy mode to the dehumidification mode, the control current In = 0 and the deviation E are obtained immediately after the mode is switched to the dehumidification mode under the setting of the target outlet temperature Teo = 1.
By setting n = 0, the capacity of the compressor 60 is increased to the maximum capacity. Thereafter, the control current In is determined through the arithmetic processing in step 360, and the capacity of the compressor 60 is controlled according to the determined control current In.

In other words, irrespective of the magnitude of the proportional gain or integral gain in the PI control equation of Equation 3, or the non-control region of the capacity of the compressor 60 (see FIG. 4B), the dehumidification mode is set. Immediately after switching, the compressor 60
Is instantaneously maximized, the target outlet temperature Teo = 1
, And dehumidification by rapid cooling can be properly performed. After a lapse of the above immediately after switching to the dehumidification mode, the compressor 60 is controlled so as to secure the target outlet temperature Teo = 1 according to the control current In based on the equation (3).
, The smooth control under the dehumidification mode is possible.

Incidentally, between the case where both steps 370 and 370a are not employed as in the conventional case and the case where both steps 370 and 370a are employed as in the present embodiment, the actual exit after the economy mode is released is described. Warm Te,
When the change of the control current In and the capacity of the compressor 60 was examined, the result as shown in FIG. 5 was obtained. That is, in the conventional case, as shown in FIG. 5A, when the target outlet temperature Teo is changed from Teo = 10 to Teo = 1 at the time of switching from the economy mode to the dehumidification mode, the target outlet temperature Teo is determined based on Equation 3. The control current In gradually decreases as shown by the solid line in FIG. 5C, and the capacity of the compressor 60 and the actual outlet temperature Te of the evaporator 30 are shown by the solid lines in FIGS. 5D and 5B. Each changes as shown.

On the other hand, in the case of this embodiment, if the target outlet temperature Teo is changed from Teo = 10 to Teo = 1 at the time of switching from the economy mode to the dehumidification mode as described above, immediately after switching to the dehumidification mode. Means that the control current In becomes In = as indicated by the broken line in FIG.
It is set to 0, and the capacity of the compressor 60 instantaneously increases to the maximum capacity as shown by the broken line in FIG. After that, the control current In determined on the basis of the equation (3) becomes equal to that of FIG.
(C) gradually increases as shown by the broken line,
The capacity of the compressor 60 and the actual outlet temperature Te of the evaporator 30 gradually decrease as indicated by broken lines in FIGS. 5 (D) and 5 (B). As a result, even if the capacity of the compressor 60 is in the non-control region,
In the case of the present invention, the capacity of the compressor 60 at the time of switching from the economy mode to the dehumidifying mode can be remarkably increased as compared with the conventional case, and the dehumidifying effect at the time of switching to the dehumidifying mode can be properly achieved. You can see that.

Next, a description will be given of a modification of the above embodiment. In this modification, the flowchart of FIG. 3 described in the above embodiment is partially modified as shown in FIG. The configuration is characterized in that the computer program is stored in advance in the ROM of the microcomputer 200 as a second computer program. Other configurations are the same as those in the above embodiment.

In this modified example configured as above, when the arithmetic processing in step 340 is completed as in the above-described embodiment, the microcomputer 200 causes the microcomputer 200 to execute step 350 (see FIGS. 3 and 6) of the second computer program. Then, it is determined whether or not the air-conditioning control device is in the economy mode. At this stage, if an economy control command signal has been generated from the economy switch S2, the microcomputer 200 proceeds to step 350
Is determined to be "YES", and in the next step 350c,
The flag F is set to F = 1, after which the second computer program is executed in step 350, as in the previous embodiment.
a, the target outlet temperature Teo is determined, the deviation En is calculated, and the current control current In is calculated, and the capacity of the compressor 70 is controlled via the capacity control mechanism 60b so as to be inversely proportional to the control current In. Then, the target opening SW is calculated, and the actual opening of the air mix damper 40 is made to coincide with the target opening SW while securing the target outlet temperature Teo via the servomotor 240. Thereby, also in this modification,
The air-conditioning control under the economy mode is performed in step 35.
The target outlet temperature Teo at 0a and the required outlet temperature Tao at step 340 are realized.

In such an economy control state,
When the economy control command signal from the economy switch S2 is extinguished and the dehumidification command signal is generated from the dehumidification switch S3, when the second computer program proceeds to step 350, the microcomputer 20
0 is determined to be "NO" based on the dehumidification command signal, and in the next step 350b, the target outlet temperature Teo is set to Teo = 1. At this stage, if the outlet temperature Te from the AD converter 190 is equal to or higher than the latest target outlet temperature Teo in step 350a, the microcomputer 200
Determines that it is immediately after switching from the economy mode to the dehumidifying mode,
S ”, and in step 410, step 350c
Is determined to be "YES" based on the flag F = 1, and the control current In and the deviation En are set to In = 0 and En = 0, respectively, in step 370a, and the second computer program proceeds to step 380 and subsequent steps, and Control mechanism 60
b, the capacity of the compressor 60 is controlled to be maximum, and the target opening SW of the air mix damper 40 is calculated according to the target outlet temperature Teo = 1, and the actual opening of the air mix damper 40 is calculated. With the target opening temperature SW while ensuring the target outlet temperature Teo = 1.

Thereafter, when the outlet temperature Te from the AD converter 190 becomes lower than the target outlet temperature Teo, when the second computer program proceeds to step 400, the microcomputer 200 "N
O ", the flag F = 0 is set in step 400a, and the second computer program is executed in step 360.
Proceeding thereafter, the calculation of the deviation En and the current control current In
And the control current I through the capacity control mechanism 60b.
The capacity of the compressor 70 is controlled so as to be inversely proportional to n, the target opening degree SW is calculated, and the actual opening degree of the air mix damper 40 is maintained via the servomotor 240 while maintaining the target outlet temperature Teo = 1. , The target opening degree SW.
As a result, the air conditioning control in the dehumidification mode is continued so as to achieve the target outlet temperature Teo = 1 and the required blowing temperature Tao in step 340. Thereafter, the control in the dehumidifying mode as described above is maintained on the assumption that the determination of “NO” is repeated in step 400.

As described above, in this modification, the economy mode control is performed under the flag F = 1 in the same manner as in the above embodiment. In such a state, when the mode is switched from the economy mode to the dehumidification mode, the target outlet temperature T
Immediately after switching to the dehumidifying mode under the setting of eo = 1, the control current In = 0 and the deviation En = 0 are set under the flag F = 1 to increase the capacity of the compressor 60 to the maximum capacity. Then, after setting the flag F = 0, the control current In is determined through the arithmetic processing in step 360, and the capacity of the compressor 60 is controlled according to the determined control current In.

In other words, irrespective of the magnitude of the proportional gain or integral gain in the PI control arithmetic expression of Formula 3, or the non-control region of the capacity of the compressor 60 (see FIG. 4B), the dehumidifying mode is set. Immediately after switching, the compressor 60
Is instantaneously maximized, the target outlet temperature Teo = 1
, And dehumidification by rapid cooling can be properly performed. After a lapse of the above immediately after switching to the dehumidification mode, the compressor 60 is controlled so as to secure the target outlet temperature Teo = 1 according to the control current In based on the equation (3).
, The smooth control under the dehumidification mode is possible. Other functions and effects are the same as those of the above embodiment.

Incidentally, each step 400, as in the conventional case,
The actual outlet temperature Te after exiting the economy mode, the control current In, and the compressor 60 between the case where 400a and 410 are not adopted and the case where each of steps 400, 400a and 410 are adopted as in the present modification. Investigation was made on how the capacitance changes, and the results shown in FIG. 5 were obtained. That is, in the case of the present modification, the target outlet temperature Teo is changed from Teo = 10 to Teo = 1 when switching from the economy mode to the dehumidification mode as described above.
Immediately after switching to the dehumidification mode, the control current In is set to In = 0 as shown by a dashed line in FIG. 5C, and the capacity of the compressor 60 is changed to
The capacity instantaneously increases to the maximum capacity as shown by the dashed line in FIG. Thereafter, the control current In determined on the basis of the equation (3) increases as shown by the dashed line in FIG. 5C, and the capacity of the compressor 60 and the evaporator 3
The actual outlet temperature Te of 0 decreases as indicated by the alternate long and short dash lines in FIGS. 5 (D) and 5 (B). As a result, even when the capacity of the compressor 60 is in the non-control region, the compressor 6 in the case of the present invention switches from the economy mode to the dehumidification mode as compared with the conventional case.
It can be seen that a significantly large capacity of 0 can be secured, and the dehumidifying effect when switching to the dehumidifying mode can be properly achieved.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to the description in the claims.

FIG. 2 is a block diagram showing an embodiment of the present invention.

FIG. 3 is a flowchart showing the operation of the microcomputer of FIG.

FIG. 4 is a graph showing a relationship between a target outlet temperature and a required outlet temperature in an economy mode, and a graph showing a relationship between a compressor capacity and a control current.

FIG. 5 is a graph showing changes in a target outlet temperature, an actual outlet temperature, a control current, and a capacity of a compressor after canceling the economy mode in the conventional case and the present invention.

FIG. 6 is a flowchart showing a main part of a modification of the embodiment.

[Explanation of symbols]

Reference Signs List 20 blower, 30 evaporator, 40 air mix damper, 50 heater core, 60 variable displacement compressor, 60b displacement control mechanism, 130 temperature setter,
140 ... internal temperature sensor, 200 ... microcomputer, S2 ... economy switch, S3 ... dehumidification switch.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B60H 1/32 623 B60H 1/32 624

Claims (1)

(57) [Claims] 1. A blowing temperature control means for controlling the temperature of a blowing air flow into a vehicle interior toward a required blowing temperature under the cooling action of an evaporator according to the capacity of a variable displacement compressor; A required outlet temperature determining means for determining in accordance with the set temperature and the internal temperature; a mode determining means for determining whether or not the economy mode is set; and a target outlet temperature of the evaporator according to the required outlet temperature when determining the economy mode. Is determined as a first target outlet temperature, and a target outlet temperature determining means for determining a constant outlet temperature as a second target outlet temperature when it is determined that the vehicle is not in the economy mode, and an actual state of the evaporator when determining the economy mode. PI control of the capacity so as to maintain the outlet temperature at the first target outlet temperature, and if the economy mode is not set. At the time of the determination, immediately after that, control is performed so as to maximize the capacity in order to maintain the actual outlet temperature of the evaporator at the second target outlet temperature, and thereafter, the actual outlet temperature is reduced to the second target outlet temperature. A vehicle air conditioning control device comprising: a capacity control unit that performs PI control of the capacity so as to maintain the outlet temperature.