JPH0592716A - Vehicle air-conditioner - Google Patents

Abstract

PURPOSE:To determine the corrective amount of the air volume on the basis of the noise level attributable to the air volume, the elapsed time from the starting timepoint of the air-conditioning operation, and the change in the thermal balance in a vehicle chamber, make a correction of the air volume target value according to the corrective amount, and improve the comfortability of the occupants. CONSTITUTION:The main part of a device is comprised of a temperature adjusting device part 1 and a control circuit part 2. In the temperature adjusting device part 1, air is sucked by an intake blower 7, and after it is cooled by an evaporator 11, it is blown into a vehicle chamber from respective blow ports 21-23 through an air mix door 18. On the other hand, the control circuit part 2 controls respective electric actuators 6, 17, 24 through respective door driving circuits 30-32 by means of a micro- computer 27 on the basis of the respective detected signals from respective sensors 33-39. The corrective amount of the air volume is determined on the basis of the noise level attributable to the air volume, the elapsed time from the starting point of the air-conditioning operation, and the change in the thermal balance in a vehicle chamber. The air volume target value is corrected according to the corrective amount.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automobile air conditioner called a car air conditioner, and more particularly to an automobile air conditioner suitable for high grade automobiles.

[0002]

2. Description of the Related Art Recently, as automobiles have become higher grade,
The demand for improving the performance of car air conditioners is increasing, and in particular, the demand for improving the quietness thereof is remarkable. Therefore, even for a relatively high-class user, a conventional air conditioner for an automobile that automatically adjusts the air volume, which is called an auto air conditioner or the like, is disclosed in Japanese Patent Publication No. 62-41127. ,
In consideration of noise, the maximum value of the air volume that can be controlled is limited to a predetermined value after a lapse of a certain time from the start of the air conditioning operation.

[0003]

The above-mentioned prior art does not consider the actual noise level in the passenger compartment.
Since the air volume is simply corrected according to the elapsed time, in vehicles with different thermal environments, the change in the air volume with respect to the elapsed time becomes complicated and diverse, and passenger comfort considering noise is reduced. There was a problem that it could not always be satisfied.

Furthermore, when the door or window is opened or the set temperature is manipulated to change the heat balance state after a lapse of a certain time during the air conditioning operation, the air volume is insufficient and a sufficient warm feeling cannot be obtained. There was a problem.

An object of the present invention is to provide an air conditioning system for an automobile, in which the noise level and the air conditioning performance are always kept in a good balance and the comfort of the occupant can be sufficiently improved.

[0006]

In order to achieve the above object, in an air conditioner for an automobile of a system in which a target value of air flow is set according to a heat load and the air flow rate is feedback controlled so as to approach the target value of air flow. A noise level detecting means for detecting a noise level signal having a correlation with the noise level resulting from the air flow rate, an elapsed time measuring means for measuring an elapsed time from the start of the air conditioning operation, and a heat balance in the passenger compartment. A heat balance change amount calculation means for calculating the change amount is provided,
A device provided with air volume correction means for determining a correction amount of the air volume based on the noise level signal, the elapsed time, and a variation amount of the heat balance, and correcting the air volume target value according to the correction amount. Is.

Further, the air volume correction means is provided with a plurality of rules for increasing the correction amount based on the noise level signal and the elapsed time as the noise level becomes higher and the elapsed time becomes longer. A correction means for determining a correction amount by inference, and the heat balance change amount calculation means calculates a room temperature deviation, which is a difference between a target vehicle interior temperature and a vehicle interior temperature calculated from a set temperature selected by an occupant, at predetermined time intervals. Then, a means for calculating the amount of change in the heat balance in accordance with the difference between the calculated room temperature deviation and the previously calculated room temperature deviation is used, and the air volume target value is used as the noise level signal detected by the noise level detecting means. It was done.

[0008]

According to the above construction, the noise level detecting means detects the noise level signal even if the target air flow rate is high due to the demand of the heat load, and the noise level detecting means starts the air conditioner for the automobile by the elapsed time measuring means. The elapsed time from the start is measured, based on the noise level signal and the elapsed time, the air volume correction means determines a correction amount for reducing the air volume, and the air volume target value is corrected according to the correction amount.

Further, even if the heat balance of the vehicle is changed after the heat balance inside the vehicle is stabilized, such as when the door or window is opened or the set temperature is changed by an occupant, the heat balance change calculation is performed. The means compares the room temperature deviation, which is the difference between the target vehicle interior temperature and the vehicle interior temperature, at predetermined time intervals with the previous time, calculates the change amount of the heat balance of the vehicle, and corrects the air flow target value based on the change amount. Therefore, there is no shortage of air flow.

Further, the air volume correction means uses a plurality of rules such that the correction amount is increased based on the noise level signal and the elapsed time as the noise level is higher and the elapsed time is longer. Since the correction by the fuzzy reasoning works, more detailed air volume control can be performed in consideration of the noise level, and the occupant's comfort is improved.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An automobile air conditioner according to the present invention will be described in detail below with reference to the illustrated embodiment. FIG. 1 is an embodiment of the present invention, and this automobile air conditioner comprises a temperature control device section 1 and a control circuit section 2 including an air volume control means. First,
Explaining the temperature control unit 1, there is an intake blower 7 in the temperature control unit 1, and the air to be sucked by this is selected by the intake door 3 and sucked from the inside air port 4 or the outside air port 5. Be done. The intake door 3 is selectively driven by an electric actuator 6.

The amount of air blown by the intake blower 7 is controlled by the voltage Vm (air amount target value) applied to the blower motor 8. Electric power (+ B) for this purpose is supplied from a battery (not shown) through the transistor 10. Then, the blower motor control circuit 9 compares the terminal voltage of the blower motor 8 with the target voltage, and the transistor 10 controls so that the terminal voltage becomes the target voltage.

The air sent by the intake blower 7 is cooled by the evaporator 11. The cooling power here is obtained by the compressor 12 using an engine (not shown) as a power source. The power of the engine is transmitted via a V-belt driven pulley 14 and a magnet clutch 13 attached to the compressor 12. And
The supply of electric power (+ Acc) to the magnet clutch 13 is interrupted by a relay 16 which operates according to an instruction from the compressor control circuit 15.

The air that has passed through the evaporator 11 is driven by an electric actuator 17 and is mixed with an air mix door 18.
As a result, air that passes through the heater 19 that uses the engine cooling water as a heat source and air that bypasses are separated. Then, the divided air is mixed in the air mix chamber 20 and then blown into the vehicle compartment from any of the vent outlet 21, the differential (defroster) outlet 22, and the floor outlet 23.

Here, the distribution of the amount of air blown out from each of the air outlets 21 to 23 is controlled by the upper door 25 and the lower door 26 driven by the electric actuator 24, and all the combinations are blown out from the vent air outlet 21. Upper mode
(UPR), vent level 21 and bi-level mode (B / L) blowing out from the floor outlet 23, and differential outlet 22
And lower mode (LWR) 3 blown out from the floor outlet 23
There is a seed.

Next, the control circuit section 2 will be described. The control circuit unit 2 has a function of controlling control, and has a built-in microcomputer 27 that performs control, judgment, and calculation. The microcomputer 27 is a central processing unit (CP).
U), read only memory (ROM) for storing programs and constants, random access memory for storing data
(RAM), input / output terminal (I / O), analog-digital conversion function (A / D), arbitrary width pulse cycle output terminal (PWM), and fixed time interval interrupt function (TIMER) are built in.
Here, this TIMER can be set to allow or disallow interrupts by a program. Further, a crystal oscillator 28 is connected to an oscillation terminal of the microcomputer 27 to form an oscillator having a constant frequency so that an accurate execution time can be obtained.

The control circuit section 2 is provided with a + B power source which is constantly supplied from a battery (not shown) and a + Ac which is supplied with a key switch position (not shown) being "Acc" and "ON".
c power supply. Then, when these power supplies are applied to the power supply circuit 29, they are converted into a constant voltage of 5V by a built-in constant voltage element, and become a + 5V power supply. Here, when the + Acc power is not supplied, the microcomputer 27 is in the reset state and the execution of the program is stopped. And + Acc
When power is supplied, the program starts executing from the beginning.

Further, the electric actuators 6, 17, 24
Are controlled via door drive circuits 30, 31, and 32 in the control circuit unit 2. In this embodiment, the solar radiation sensor 33,
Outside the temperature setting volume 34, an outside air temperature sensor 35,
Inside air temperature sensor 36, defroster duct temperature sensor 3
Five temperature sensors, 7, a vent duct temperature sensor 38 and a floor duct temperature sensor 39, are provided, and the voltage signals from them are independently supplied to the microcomputer 2
It is supplied to the A / D terminal 7 and is used for calculation after being converted into digital binary data.

Next, the ROM of the microcomputer 27
The control content of the temperature control device unit 1 executed by the processing procedure stored in FIG. The processing procedure by the microcomputer 27 includes background processing (BGJ) repeatedly executed at a cycle of about 20 milliseconds shown in the flow of FIG.
TIMER of the microcomputer 27 shown in the flow of FIG.
Is used to divide the background processing (BGJ) at a predetermined time interval (5 milliseconds in this embodiment) into a timer processing which is executed. When this timer process ends, the background process
(BGJ) restarts the process after the suspended process. Here, the numbers in the drawings of the respective flows indicate step numbers.

First, in the background processing (BGJ) of FIG.
The step 100 is executed only once when + Acc is supplied, sets the output terminal of the I / O of the microcomputer 27 so that the external device stops, and sets the flag (Fm, Fm, Fh, Fv) and the counters (Ct, Ch, Cm, Cv) for storing the numbers are all set to 0, and then the TIMER interrupt is permitted. That is, the microcomputer 27 is initialized before the control is started.

In step 200, the outside air temperature sensor 3
5, inside air temperature sensor 36, differential duct temperature sensor 37,
The signal voltages of the vent duct temperature sensor 38, the floor duct temperature sensor 39, the solar radiation sensor 33, and the temperature setting volume 34 are converted into digital amounts and input. further,
The outside temperature Ta, the inside air temperature Tr, and the differential duct temperature Td used for control are calculated by using the conversion characteristics of the signal voltage, the temperature, and the amount of solar radiation stored in the microcomputer 27 in advance.
d, vent duct temperature Tdu, floor duct temperature Td
1, the amount of solar radiation Zm and the set temperature Ts are obtained.

In step 300, the following calculation is performed.

First, the deviation ΔTr (room temperature deviation) of the inside air temperature Tr from the set temperature is calculated by the equation (1). ΔTr = Ts−Tr (1) Next, the target outlet air temperature Tdod (differential outlet), Tdou (vent outlet), Tdol (floor outlet) for each outlet, Tdox (2) ). Tdox = Kbx · Tdbx−Kzx · Zm + Kdx · ΔTr (2) Here, Kbx, Kzx, and Kdx are constants, and the reference outlet temperature Tdbx is a comfortable outlet temperature characteristic in the steady state shown in FIG. 7.

Further, the target outlet temperature Tdo for each outlet
temperature difference ΔT between x and the detected outlet temperature Tdx (x = d, u, l)
dx is calculated by the equation (3). ΔTdx = Tdox−Tdx (3) When the air outlet is in the upper mode (UPR), ΔTdx = ΔTdu (4), and when the air outlet is in the lower mode (LWR), ΔTdx = ΔTdd (5) ), And avoid using the temperature of the air outlet where there is no wind.

Further, the outlet control signal α is calculated by the equation (6). α = Kam · Ta + Kzm · Zm−Ksm · Ts + Kom (6) where Kam, Kzm, Ksm, and Kom are constants.

In step 400, in step 300
The outlet is determined by the outlet control signal α obtained by the equation (6), and a signal is output to the door drive circuit 31. Step 50
At 0, the temperature difference ΔTd calculated by the equation (3) in step 300.
The suction port is determined by x, and a signal is output to the door drive circuit 30.

The calculation of the blower voltage Vm which is the air flow target value in step 600 will be described with reference to the flow chart of FIG. First, in step 610, the maximum value (V) of the blower voltage is determined by the outside air temperature Ta, the set temperature Ts, and the solar radiation amount Zm.
Mmax) and minimum value (VMMin) are determined. At the next step 620, it is determined from the room temperature deviation ΔTr obtained by the equation (1) of step 300, the maximum value VmMax and the minimum value VMmmin of the blower voltage obtained at step 610, according to the heat load of the vehicle. The blower voltage Vm required to obtain the air volume is obtained.

The blower voltage control processing in step 630 will be described with reference to the flow chart of FIG. First, in step 631, it is determined whether or not the flag Fv set at a predetermined time set longer than the time constant of the inside air temperature sensor 36 is set. If this is false, the process proceeds to step 638, and if true, For example, Fv is cleared in step 632 and the process proceeds to step 633.

At step 633, at step 300
The difference between the absolute value of the room temperature deviation ΔTr calculated by the equation (1) and the absolute value of the previously calculated room temperature deviation ΔTr ′ is calculated as the vehicle heat balance change amount, and compared with a predetermined value ΔTro. Proceeding to step 634, a predetermined value Ct ′ is obtained according to the amount of change, and proceeding to step 635. Otherwise, go to step 637.

In step 635, it is compared whether or not the value of the counter Ct corresponding to the later-described elapsed time is larger than the predetermined value Ct ', and if the result is true, in step 636 Ct.
Is set to Ct ′, and if false, the value of Ct is left as it is and the process proceeds to step 637. In step 637, the value of ΔTr, which is the room temperature deviation, is calculated as the room temperature deviation Δ calculated last time.
Substitute for Tr ′ and proceed to step 638.

In step 638, the value of the counter Ct is multiplied by the constant Ap to convert the elapsed time tp from the start of the + Acc power supply. Next, in step 639, the blower voltage Vm obtained in step 600 and the elapsed time t
From p and p, the correction amount ΔV of the blower voltage considering the noise due to the influence of the blower voltage is obtained by fuzzy inference. After that, the correction amount ΔV is subtracted from the blower voltage Vm, and this value is used as a target value of the blower voltage, and a signal is output to the blower motor control circuit 9.

Correction amount ΔV performed in step 639
The calculation method based on the fuzzy inference will be described in detail below.

The correction amount ΔV of the blower voltage is the blower voltage V
It is set by a rule executed based on m and the elapsed time tp. This rule is expressed by the following seven logical expressions. For example, the rule (R1) is "if (i
f) Blower voltage (Vm) is high, and (and) elapsed time t
If p is long (then), the correction amount is increased. ” At this time, in this embodiment, the value of the blower voltage Vm is regarded as the noise level signal. That is, the process of step 620 for calculating the blower voltage Vm serves as the noise level detecting means. Here, even if noise is directly detected and inferred by a voice recording device such as a microphone,
Of course it doesn't matter. In this case, the voice recording device serves as a noise level detecting means, and the noise value [dB] serves as a noise level signal.

[Rule] if (Vm = HV and tp = LT) then (ΔV = LD) ...... (R1) if (Vm = HV and tp = MT) then (ΔV = MD) ...... (R2) if ( Vm = HV and tp = ST) then (ΔV = ZD) ...... (R3) if (Vm = MV and tp = LT) then (ΔV = MD) …… (R4) if (Vm = MV and tp = MT) then (ΔV = ZD) ・ ・ ・ (R5) if (Vm = MV and tp = ST) then (ΔV = ZD) ・ ・ ・ (R6) if (Vm = LV) then (ΔV = ZD) ・ ・ ・ (R7) In the rule, the blower voltage Vm is classified into a set of three noise levels of “high (HV)”, “medium (MV)”, and “low (LV)” as a result of the noise determination means, and the elapsed time tp
Is divided into a set of lengths in three stages of "long (LT)", "slightly long (MT)", and "short (ST)".

As shown in FIGS. 9 (a) and 9 (b), each of these partitioned sets has a range of the set and a degree of membership of consecutive values from 0 to 1 in the range depending on the membership function. Is set. The values of V1 to V3 and t1 to t3 shown in the domain of this membership function are constants set according to the conditions of the vehicle and the temperature control device in this embodiment.

However, depending on the vehicle, the noise level may be different even at the same blower voltage depending on the positions of the intake door 3 and the outlet doors 25 and 26. In such a case, the position of each door is a function. The V1 to V3 may be determined, or the values of V1 to V3 may be mapped and used for each position of each door.

The output correction amount ΔV has three levels of "low (LD)", "slightly low (MD)", and "hold (ZD)", and its membership function is shown in (c) of FIG. ) Is set. Note that dV1 to dV5 in the figure are constants, and the membership functions ZD and LD are
It is selected so as to be line-symmetric with respect to the vertical axis (in this embodiment, an isosceles triangle), and the axes of symmetry are determined to be the minimum and maximum ΔV values, respectively.

Next, the fuzzy inference procedure will be described with reference to the concrete examples shown in FIGS. In the specific example of FIG. 10, the blower voltage calculated in step 620 is Vm = 10 [V], and the elapsed time tp = 17.5.
[Minutes], constants V1 to V3 [V], t1 to t3
[Min], dV1 to dV5 [V] are respectively V1 = 6, V2 = 9, V3 = 11 t1 = 2.5, t2 = 10, t3 = 20 dV1 = -1.5, dV2 = 0, dV3 = 1.5, dV4
= 3 and dV5 = 4.5.

First, the input Vm and tp are applied to the rules (R1) to (R7). Here, the output ΔV
The rules (R1), (R2), (R
4), (R5). Next, the rule adaptation will be described by taking the case of (R1) as an example. Applying the rule (R1), the membership degree of the membership function LN of Vm is 0.5 and the membership degree of the membership function LT of tp is 0.75, as shown in the first line of FIG. These “and
(and) ”means that the membership degree of LN and LT is the smallest value. Therefore, in rule (R1), the membership degree of 0.5 is the membership degree of ΔV, which is the output. The function LD is allowed, and LD is truncated at the degree of membership of 0.5. Similarly, if the rules (R2) and below are applied, a membership function of ΔV as shown in the third column of FIG. ..

Second, all the obtained membership functions of ΔV for each rule are “or”. Where “or”
To take the value that has the largest degree of belonging to each value of the horizontal axis ΔV, and as a result, as shown in FIG.
A membership function for an output ΔV of 1 is obtained.

Thirdly, ΔV obtained as shown in FIG.
Defuzzify by taking the weighted average of the membership function of. Then, assuming that this value is most certain, it is used for actual control. Here, as the defuzzification method, various other methods such as taking a value with the highest degree of belonging have been proposed, but in this embodiment, the weighted average, which is the most general method in the fuzzy control field, is used.

Next, considering the case where the value of Vm is larger than 10 [V], the degree of belonging of LD is shifted from rule (R1) to the direction in which the degree of belonging of MD is higher than that of rule (R4). Then, the center of gravity of the membership function of ΔV shifts to the right as a whole. Therefore, the higher the value of the blower voltage Vm, the more Δ
It can be seen that V becomes large. Also, the value of tp is 17.5.
When it becomes larger, the degree of belonging of MD is rule (R2)
From the above, according to the rule (R5), the degree of membership of ZD is shifted to the lower side, and the center of gravity of the membership function of ΔV is shifted to the right as a whole. Therefore, it can be seen that the longer the elapsed time tp, the larger ΔV.

Next, the processing after step 700 in FIG. 2 will be described. First, in step 700, the outside temperature T
Processing for turning on and off the magnet clutch 13 is executed according to a.

In step 800, it is judged whether or not a flag Fm indicating permission to execute temperature adjustment is set,
If it is true, the process proceeds to step 900 after clearing this Fm, and if false, the process returns to step 200.

Next, details of the air mix door control processing in step 900 will be described with reference to FIG. First, in step 901, it is determined whether or not the absolute value of the weighted values of ΔTdl and ΔTdu is smaller than the predetermined value Dul. Here, Kul is a constant. Then, first, in the case of false, it is assumed that the respective outlet temperatures have not reached the target, and in step 902, the voltage application time Ch (A
ul is a constant) and voltage is applied.

However, when it is true, Ch is set to 0 in step 903, assuming that each blowout temperature is controlled to the target. Then, in step 904, a voltage is applied to the door drive circuit 31, and a flag Fh indicating that the voltage is being applied is set. After completion of step 900, the process returns to step 200 is repeated.

Next, the contents of the TIMER processing which is interrupted at predetermined intervals while the above processing is repeatedly executed will be described with reference to FIGS. 6 and 7. Step 1000 in FIG. 6 is an elapsed time measuring means, and as shown in FIG. 7, it is determined in step 1010 whether the counter Ct for counting the elapsed time is smaller than a predetermined maximum value tmax (= t3). 1100, and if true, Ct is incremented in step 1020, and step 110
It goes to 0.

In step 1100, it is determined whether Fh is set and the electric actuator 17 is being driven. If true, in step 1110, Ch is counted down. In step 1120, it is determined whether or not this Ch becomes 0 or less and it is time to stop the electric actuator 17. If true, Fh is cleared in step 1130, and the electric actuator 17
To the door drive circuit 31.

In step 1140, the counter Cm that makes the temperature control execution cycle is counted down, and then step 1
At 150, it is determined whether or not this Cm becomes 0 or less and it is time to execute the temperature adjustment. If true, Fm is set in step 1160, and Cm is given a predetermined execution cycle Cmo.

In step 1170, the counter Cv is counted down, and in step 1180, it is judged whether or not the Cv becomes 0 or less and it is time to calculate the increase amount of the vehicle heat load. If true, step 1190 Then, Fv is set by and the predetermined execution cycle Cvo is given to Cv.

Therefore, according to this embodiment, the higher Vm is based on the value of the target blower voltage Vm and the elapsed time tp,
Fuzzy inference using rules (R1) to (R7) is performed such that the longer the tp, the lower the blower voltage, and the correction value ΔV of Vm according to the situation is determined.
Since the blower voltage is corrected by V, the occupant's comfort can be sufficiently improved.

Further, according to this embodiment, even after a considerable time has elapsed since the start of the air conditioning operation, the room temperature deviation Δ
When the absolute value of Tr increases by at least the predetermined value ΔTro or more, the elapsed time tp is corrected so as to be short, so that a sufficient air volume can always be obtained.

[0053]

According to the present invention, in consideration of both the elapsed time from the start of air conditioning and the noise level, the air volume is finely corrected and controlled by fuzzy reasoning, if necessary, and the air volume is insufficient even when the heat balance changes. Since it is controlled so that it does not become a problem, the necessary temperature adjustment can be obtained without disturbing the noise, and the comfort can be sufficiently improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of an automobile air conditioner according to the present invention.

FIG. 2 is an explanatory diagram of a background processing flow according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram of a blower target voltage calculation processing flow in one embodiment of the present invention.

FIG. 4 is an explanatory diagram of a blower voltage control processing flow according to an embodiment of the present invention.

FIG. 5 is an explanatory diagram of an air mix door control processing flow according to the embodiment of the present invention.

FIG. 6 is an explanatory diagram of a TIMER processing flow according to an embodiment of the present invention.

FIG. 7 is an explanatory diagram of an elapsed time measurement processing flow according to the embodiment of the present invention.

FIG. 8 is a characteristic diagram of a reference outlet temperature in one embodiment of the present invention.

FIG. 9 is an explanatory diagram of a membership function according to an embodiment of the present invention.

FIG. 10 is an explanatory diagram showing a specific example of fuzzy inference according to an embodiment of the present invention.

FIG. 11 is an explanatory diagram showing a specific example of fuzzy inference according to an embodiment of the present invention.

[Explanation of symbols]

 1 Temperature Controller 2 Control Circuit (Air Volume Control) 3 Intake Door 4 Inner Air Outlet 5 Outer Air Outlet 6, 17, 24 Electric Actuator 7 Intake Blower 8 Blower Motor 9 Blower Motor Control Circuit 10 Transistor 11 Evaporator 12 Compressor 13 Magnet Clutch 18 Air Mix door 20 Air mix chamber 21 Vent outlet 22 Def (defroster) outlet 22 23 Floor outlet 620 Noise level detection means 633 Heat balance change amount calculation means 639 Air volume correction means 1000 Elapsed time measurement means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Norio Kagohata 2520 Takaba, Katsuta City, Ibaraki Prefecture Hitachi Ltd. Automotive Equipment Division

Claims (4)

[Claims] 1. In an automotive air conditioner of a system in which a target air flow rate is set according to a heat load and the air flow rate is feedback controlled so as to approach the target air flow rate, a correlation with a noise level caused by the air flow rate is obtained. A noise level detecting means for detecting a noise level signal, an elapsed time measuring means for measuring an elapsed time from the start of the air conditioning operation, and a heat balance change amount calculating means for calculating a heat balance change amount in the passenger compartment. An air volume correction unit is provided that determines a correction amount of the air volume based on the noise level signal, the elapsed time, and a change amount of the heat balance, and corrects the target air volume value according to the correction amount. An air conditioning system for automobiles characterized by the above. 2. The invention according to claim 1, wherein the air volume correction means increases the correction amount based on the noise level signal and the elapsed time as the noise level becomes higher and the elapsed time becomes longer. An air conditioner for an automobile, which is a correction means for determining a correction amount by fuzzy inference provided with a plurality of rules. 3. The invention according to claim 1, wherein the heat balance change amount calculating means calculates a room temperature deviation for a predetermined time as a difference between a target vehicle interior temperature calculated from a set temperature selected by an occupant and an actual vehicle interior temperature. An air conditioner for an automobile, characterized in that it is means for calculating the change amount of heat balance according to the difference between the calculated room temperature deviation and the previously calculated room temperature deviation. 4. The automobile air conditioner according to claim 1, wherein the noise level detecting means is means for detecting the air flow target value as a noise level signal.