JPH0325022A - Automobile airconditioner - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an air conditioner for automobiles using an externally controlled variable capacity compressor. The present invention relates to a capacity control device suitable for stably controlling the air temperature at the outlet of an evaporator.

[Conventional technology]

The conventional air conditioner for automobiles is disclosed in Japanese Patent Application Laid-Open No. 62-9474.
As described in Publication No. 8, the target evaporation pressure of the evaporator is determined from the target value and the detected value of the outlet temperature of the evaporator in order to obtain the required blowing air temperature, and further, the detected evaporation pressure is set to the target evaporation pressure. The capacity of the compressor was controlled so that it approached.

[Problem to be solved by the invention]

In the above conventional technology, the heat load of the introduced air and the rotation speed of the compressor change depending on the driving conditions of the vehicle, and the response of the refrigeration cycle also changes. Not determined. Therefore, in order to stably control the evaporator outlet air temperature, it is necessary to reduce the control gain or to extend the timing of the control, resulting in the problem that it is difficult to reach a comfortable blowing temperature.

An object of the present invention is to stably converge the evaporator outlet air temperature to a target value in a short time and maintain a comfortable blowout temperature.

[Means to solve the problem]

In order to achieve the above purpose, a compressor is driven by an automobile engine and equipped with a variable capacity device, an evaporator cools the air introduced into the vehicle interior, and a control signal is calculated based on the outlet air temperature of the evaporator. , an air conditioner for an automobile having a capacity control means for controlling the capacity of the compressor according to the control signal, wherein the capacity control means applies a reference control signal such that the evaporator outlet air temperature reaches the target value to the inlet air of the evaporator. temperature,
A predictive calculation is performed based on the air volume, a predetermined width is provided above and below the reference control signal, and the control signal is limited within the width.

The reference control signal is calculated by proportionally calculating a reference refrigerant evaporation pressure based on the target value of the evaporator outlet air, the temperature and air volume of the evaporator inlet air, and calculating the reference refrigerant evaporation pressure based on a predetermined relationship from the reference refrigerant evaporation pressure. It was designed so that

[Effect]

The capacity control means performs a proportional calculation and predicts the reference refrigerant evaporation pressure at which the outlet air temperature of the evaporator reaches a target value, the temperature of the inlet air of the evaporator, and the air volume, which mainly affect the outlet air temperature. Next, a reference control signal is determined from the reference refrigerant evaporation pressure based on a predetermined relationship between the refrigerant evaporation pressure and the control signal. Further, a predetermined width is provided above and below the reference control signal by an allowable variation range that can maintain passenger comfort, and within the width, based on the outlet air temperature of the evaporator and the target value of the outlet air temperature, A control signal is calculated, and the capacity of the compressor is controlled by a capacity variable device based on the control signal. Therefore, the evaporator outlet air temperature converges to the target value in a short time and stably, and a comfortable blowout temperature is obtained.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 8.

FIG. 1 is a block diagram of an air conditioner for an automobile, which is an embodiment of the present invention. The device consists of a temperature control device section 1 and a control circuit section 2.

The functions of the temperature control unit 1 will be explained. Air is selected by an intake door 3, which is a suction means, and is sucked in through an internal air port 4 or an external air port 5. The door 3 is driven by an electric actuator 6.

Air is sent by a blower 7, which is a blowing means, and the amount of air blown is controlled by a voltage VM' applied to a motor 8. Electric power (10 B) is supplied from a battery (not shown), a blower control circuit 9 compares the voltage across the motor 8 with a target voltage, and a transistor 10 controls the voltage across the motor 8 to the target voltage.

The air is cooled in the evaporator 11.

Note that the cooling power is adjusted by controlling the refrigerant flow rate using a capacity actuator 13 built into the compressor 12. The capacity actuator 13 is an electromagnetic solenoid, and the opening degree of the refrigerant flow rate control valve can be changed depending on the applied voltage. The power source of the compressor 12 is an engine (not shown), and the power to the compressor 12 is switched on and off by a magnetic clutch 15 located between the compressor l2 and a pulley 14 connected to the engine by a V-belt. The supply of electric power (+Acc) to the magnetic clutch 15 can be interrupted or interrupted by a relay 17 that operates according to instructions from a compressor control circuit 16.

The air that has passed through the evaporator 11 is passed through an air mix door 19 driven by an electric actuator 18.
The air is divided into air that passes through the heater 20 and air that bypasses it. The heater 20 is equipped with cooling water for the engine (approximately 80%
This is a heating means that uses a temperature (°C) as a heat source.

A differential door 21 and a belt door 22, which serve as air blowing means, are linked by a link 23 and driven by an electric actuator 24. Depending on the positions of the defroster door 21 and the vent door 22, the distribution of air volume blown into the vehicle from each of the differential air outlet 25, vent air outlet 26, and floor air outlet 27 is controlled. There are three combinations of air outlet, all of which are upper mode (UPR) where air is emitted from the vent air outlet 26. Pie level mode (B/L) that blows out from the vent outlet 26 and floor outlet 27. Then, the differential air outlet 25 and the floor air outlet 2
This is the lower mode (LWR) that blows out from 7.

Next, the control circuit section 2 will be explained. The control fjR circuit section 2 has a control function, and includes a microcomputer 28 which is a control means, a judgment means, and a calculation means. The microcomputer 28 of this embodiment is a central control unit (CPU). Read-only memory (ROM) that stores processing procedures (program 5 constants). Random access memory (RAM) that stores data, input/output terminals (
I/O), analog/digital conversion function (A/D>.
Built-in arbitrary width pulse output terminal, arbitrary frequency pulse output terminal, pulse period counting terminal, and fixed time interrupt function.

A crystal oscillator 29 is connected to the oscillation terminal of the microcomputer 28 to constitute an IMHz oscillator, and the program progresses at 1 cycle = 1 microsecond.

The control circuit unit 2 is supplied with a 10B power supply which is constantly supplied from a battery (not shown) and a +Ace power supply which is supplied evenly to key switch positions (not shown) at "ACC" and "○N". When these power sources are applied to the power supply circuit 30, the built-in constant voltage element causes It is converted to a 5V constant voltage and becomes a +5V power supply.

Further, the control circuit unit 2 includes a switch 32 for instructing on/off of the system, and an indicator lamp 32 for the switch 3. When the off signal from the switch 31 is given to the blower control circuit 9 and the compressor control circuit 16, each circuit stops the motor 8 and disconnects the magnetic clutch l5.

The electric actuator 6, 18.24 is connected to the drive IC [
For example, the door drive circuits 33, 34 . , 35. In this embodiment, seven temperature sensors, a solar radiation sensor 36, and a temperature setting volume 37 are provided, and their voltage signals are independently applied to the A of the microcomputer 28.
It is connected to the /D terminal and used for calculations after being converted to digital binary data.

Hereinafter, regarding the control contents of the temperature control device section 1, the processing procedure stored in the ROM of the microcomputer 28,
That is, the explanation will be made using the flows shown in FIGS. 2 to 5.

The program uses the background processing (BGJ) as shown in FIG. 2, which is repeatedly executed at a cycle of about 100 milliseconds, and the time interrupt function of the microcomputer 28, at predetermined time intervals (5 milliseconds in this example). Then, suspend the BGJ. The timer processing (TIME
R). Furthermore, when the TIMER ends,
The BGJ resumes processing from the time it was paused. Also,
The numbers in each flow diagram indicate step numbers.

In step 100 of FIG. 2, the I/O output terminal of the microcomputer 28 is set so that external equipment is stopped, and a flag (
Fh, Fm). and a counter (Ch,
Cm) are all set to O. That is, before starting control, the microcomputer 28 is brought into an initial state.

In step 150, outside air temperature sensor 40, inside air temperature sensor 41, differential duct temperature sensor 42, vent duct sensor 43, floor duct temperature sensor 44, evaporator outlet air temperature sensor 45. The signal voltages of the evaporator inlet air temperature sensor 46, the solar radiation sensor 36, and the temperature setting volume 37 are converted into digital quantities and input. Furthermore, the information is stored in the microcomputer 28 in advance. Using the signal voltage, temperature, and solar radiation conversion characteristics, the outside air temperature Ta. Shy? degree Tr, differential duct temperature Tdd, vent duct temperature Tdu, floor duct temperature Tax, air forator outlet air temperature Tc. Obtain the evaporator inlet air temperature T1, the amount of solar radiation Z, and the set temperature Ts.

In step 200, the following calculations are performed.

The target cabin temperature Tso is Tso=Kas-Ta+Kss-Ts Kos
-(1), where Kas*Kss and Kos are constants.

The amount of deviation ΔTr of the internal air temperature T from the target value is ΔTr=
Ksr−Tso K, r−T, +Kor ・=(2
), and K■e Kr and Kor are constants.

Target outlet temperature Taoa for each outlet (differential outlet 25)
, T. +ou (vent outlet 2 6). 'r
．． +on (floor outlet 27), collectively known as T dOX
is Taox=Kbx−Tabx Kz1Z−+Ks
Calculated by x-TS KF1Tr+Kox - (3),
K b x + K z x H K s x * K
p x @K o x is a constant, standard blowing temperature Tab
i (differential air outlet 25), Tdbu (vent air outlet 26)
．． Tab area (floor outlet 27), collectively referred to as T a
b x is the comfortable blowing temperature characteristic in the stable state shown in FIG.

The temperature difference ΔTdx between the target outlet temperature T aox and the detected outlet temperature T'ax is as follows: ΔTo=Kbu-Taax Kuu-Tmx+K
．． Calculate by u = (4), K b u H K u u
, K a u are constants. In addition, in the upper mode (UPR), ΔTat=Δ”r mu −(
5), and in the lower mode (LWR), ΔT d
u = Δ'r at ・(6)
to avoid using the temperature of the outlet where no air is coming out.

The air outlet control signal α is calculated by a−Kam ・Tt+Kz1Zm Ksm ・Ts×Kam −(7),
Ksm+Koa is a constant. The outlet target air temperature Tco of the evaporator 11 is determined according to FIG. 7 as a function of T1.

That is, Tco is determined so that when T8 is a low temperature, dehumidification is performed to prevent windows from fogging. When the temperature is high, Tco is kept constant so that there is no effect on the blowout temperature.

In step 250, the air outlet is determined based on α determined by equation (7) in step 200, and a signal is output to the door drive circuit 35.

In step 300, the voltage VM to be applied to the motor 8 is determined based on ΔT determined by equation (2) in step 200, and a signal is output to the blower control circuit 9.

In step 350, (4) and (6) of step 200
The suction port is determined based on ΔT du determined by the formula, and a signal is output to the door drive circuit 33.

In step 400, it is determined whether the flag F1 indicating permission to perform temperature adjustment is set, and if true, the flag F1 indicating permission to perform temperature adjustment is set. After clearing, proceed to step 450, and if false, proceed to step 1
Return to 50.

A detailed flow of compressor control, which is the capacity control means in step 450, is shown in FIG. In step 451, Tc
It is determined whether the absolute value of the difference ΔTc (=Tco Tc) between o and Tc is smaller than a predetermined value αC. If true, in step 452. If no capacitance change is necessary, the capacitance change amount ΔVc is set to O by the evaporator 11, and if false, in step 453, ΔVc is set to Kc·ΔTc (Kc is a constant). In step 454, the ΔVc is added to the voltage Vc currently being applied to the capacitive actuator l3 to obtain a new Vc.

In step 455, the blower voltage VM, the evaporator inlet air temperature Tt. and target outlet air temperature Tco, T
It is predicted that c is equal to Tco.

Calculate the reference refrigerant evaporation pressure Pso. (KPMI KP
lPK pc and K ps are constants. ) step 456
Now, the reference applied voltage V c b is determined from the Pso. Here, the function f has the characteristics shown in FIG. In step 457, the upper limit value Vc of the applied voltage is determined from the Vcb.
x. and find the lower limit value V c n. (Kvx, K
vn is a constant. ) In this embodiment, both Vcx and Vcn are
The capacity of the compressor 12 is controlled so that the voltage is approximately 0.5v, and the width of Pso is 0.5kg/d. therefore,
The change in outlet air temperature in this range is about 5 dags, which is within the allowable range for maintaining comfort. In step 458,
VC is VC! If it is true, in step 459, Vc is set to Vc x. In step 460, it is determined whether Vc is smaller than Vcn, and if so, Vc
is output as is, and when true, in step 461, Vc is changed to Vcn and Vc is output.

Details of the air mix door control in step 500 are shown in FIG. In step 501, the ΔTag and the Δ
It is determined whether the absolute value of the weighted value of T au is smaller than a predetermined value αold. (Ko is a constant.) If it is false, it is assumed that the blowing temperature has not reached the target, and in step 502, the voltage application time ch (A,, is,
constant. ) and apply the voltage. If true, each outlet is controlled to the target outlet temperature, and step 50 is performed.
Set Qh to O in step 3. In step 504, a voltage is applied to the door drive circuit 34, and a flag F indicating that voltage is being applied is set.

After step 500 ends, returning to step 150 is repeated.

The processing contents of the TIMER, which is executed at predetermined time intervals while the above processing is repeatedly executed, will be explained with reference to FIG.

In step 601, the Fh is set and it is determined whether the electric actuator 18 is being driven. If true, the Ch is counted down in step 602. In step 603, it is determined whether the Ch becomes below O and it is time to stop the electric actuator 18. If true, in step 604, the F 1+
is cleared, and a stop signal for the electric actuator 18 is output to the door drive circuit 34.

In step 605, a counter C. is counted down, and in step 606, the corresponding C
Determine whether II has become O or below and it is time to permit execution. If true, in step 607 the F. is set, and the execution cycle Cao is given to C.

According to this embodiment, the reference refrigerant pressure Pso at which the evaporator outlet air temperature Tc becomes the target value Tea is set to the blower voltage vM
, evaporator inlet air temperature Tt. Accordingly, calculate and predict proportionally. Further, according to the characteristics shown in FIG. 8, the reference applied voltage Vcb is determined from the Pso, and the applied voltage is determined within a predetermined value set so that an allowable temperature change range above and below Vcb that maintains the comfort of the occupants is obtained. Since the voltage Vc is controlled, the evaporator outlet air temperature Tc is stably controlled around the target value Tea, and a comfortable blowing temperature can be maintained.

〔Effect of the invention〕

According to the present invention, the outlet air temperature of the evaporator stably converges to the target value in a short time, so that a comfortable blowing temperature can be maintained.

[Brief explanation of drawings]

Fig. 1 is a block diagram of an automobile air conditioner which is an embodiment of the present invention, Figs. 2 to 5 are processing flow diagrams stored in the microcomputer shown in Fig. 1, and Figs. 6 to 8 are characteristic diagrams of the reference blowing temperature, the target evaporator outlet air temperature, and the applied voltage, which are respectively stored in the microcomputer in the drawing. 1l... Evaporator, 12... Compressor, 4
5... Evaporator outlet air temperature sensor, 46...
Evaporator inlet air temperature sensor, 450...combre^ 1 Figure porridge 2 Figure bow 4 Figure angle ÷ 3 Figure angle) 5 Figure;

Claims (1)

[Claims] 1. A compressor driven by an automobile engine and equipped with a variable capacity device, an evaporator that cools air introduced into the vehicle interior, an outlet air temperature of the evaporator, and a target value of the outlet air temperature. In the automotive air conditioner, the capacity control means calculates a control signal based on the control signal and controls the capacity of the compressor based on the control signal, wherein the capacity control means calculates a reference control signal such that the evaporator outlet air temperature becomes the target value. is predicted and calculated based on the temperature and air volume of the inlet air of the evaporator, a predetermined width is provided above and below the reference control signal, and the control signal is limited within the width. air conditioning equipment. 2. In claim 1, the reference control signal is obtained by proportionally calculating a reference refrigerant evaporation pressure based on the target value of the evaporator outlet air, the temperature of the evaporator inlet air, and the air flow rate. A capacity control device characterized in that calculation is performed based on a more predetermined relationship.