JPS6086350A - Air conditioner - 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 a control device for an air conditioner for automobiles, etc., and relates to a control system for an expansion valve in a refrigeration cycle.

(Prior art) (1) Conventional refrigeration cycle expansion valves are generally automatic temperature sensitive types that keep the amount of superheat constant, and other components and means are used to control the cycle's frost prevention and overload prevention capabilities. However, the cycle becomes complicated, and it is not an effective system.

(Objective of the Invention) An object of the present invention is to provide an air conditioner having a refrigeration cycle that can perform superheat amount control and other controls comprehensively.

(Structure of the Invention) The present invention includes a first calculation means for calculating the amount of superheat, and a second calculation means for using the calculation result as a basic parameter and other parameters related to cycle operation as a correction factor. , the throttle amount of the control valve is controlled continuously or stepwise based on the calculation result of the second calculation means.

(Example) In FIG. 1 showing the main structure, a compressor 1, a capacitor 2. Fan 3. Cash register/l,! ! (2) Adjustable expansion control valve5. The evaporator 6 and the fan 7 constitute a refrigeration cycle. The amount of throttle of the control valve 7 is electrically controlled by a stepping motor 8. Stepping motor 8 is driven by electric control circuit 9 . Sensors 10 to 14 are connected to the electric control circuit 9,
These sensors detect and provide low pressure (evaporator discharge side refrigerant pressure) PLE, evaporator discharge side refrigerant temperature TPO, evaporator downstream air ITEo, high pressure (compressor discharge side refrigerant pressure) Pc, and required cooling capacity Q. .

In the electric control circuit 9, the input signal PLE from the low pressure sensor 10 is input to the conversion circuit 15, and a signal S1 representing the basic throttle amount for the low pressure is output. This signal S
I is input to the conversion circuit 16, converted into a signal representing the saturation temperature A, and input to the subtraction circuit 17. Subtraction circuit 17
Now, the difference between the saturation temperature A and the evaporator discharge side refrigerant temperature TRO from the sensor 11 is determined, and this difference is given to the conversion circuit 18 to calculate the throttling correction amount for the superheat amount as shown in Table (3).
) is immediately converted into signal S2. In the adder circuit 19, the signal S
I and 82 are added to produce a signal SI2 representing the basic throttling amount of the control valve 5 in consideration of the amount of superheat.

FIG. 3 shows the throttle amount signal 3 for the low pressure PLE of the control valve 5.
In this characteristic, the entire characteristic is increased within the range of the minimum and maximum value MAX according to the amount of superheat indicated by the signal S2.

The above basic signal SI2 is input to the synthesis arithmetic circuit 20. In addition to the basic signal S12, the synthesis calculation circuit 20 receives a signal S3 representing a plurality of parameters related to cycle operation.
．． S4+S5 are input, and the composite signal So of these signals is
is taken out.

The signal S3 is related to the high pressure Pc from the high pressure sensor 13. The signal of the sensor 13 is compared with a predetermined value by the comparator 21, and when it exceeds the predetermined value, the signal generator 22 activates the control valve 1.
A signal ( ) S3 is generated that closes the aperture amount of No. 5 by a certain amount.

If the high pressure Pc is below a predetermined value, the signal S3 means 0''.This means that if the high pressure Pc becomes higher than a certain pressure,
Book (4) By closing the expansion valve lift amount by a certain amount, high pressure can be lowered and the cycle can be kept on the safe side. By maintaining the high pressure at a high level during the normal cycle, this makes it possible to reduce the rotation of the condenser cooling fan 3 during the normal cycle, which is very effective in reducing noise and saving power.

The signal S4 is related to the air temperature TEO on the downstream side of the evaporator from the sensor 12. The sensor signal is compared with a predetermined value in the comparator 23, and if it is less than that, the signal generator 24 reduces the throttle amount by a certain amount. Only open signal (+) S4
occurs. If TEO is above a predetermined value, signal S4 is aO
” means.

This makes it possible to prevent the evaporator 2 from frosting.

The signal S5 is related to the cooling capacity Q, and if the sensor 14 is constituted by, for example, a manual switch, the signal generator 25 generates the signal S5 to change the throttle amount depending on whether the switch is turned on or off.

In this case, as we try to reduce the cooling capacity Q,
The signal S5 is caused to decrease. For example, (5) the sensor 14 and the signal generator 25 can be replaced with ones that generate a signal depending on the room temperature or the difference between the room temperature and the set temperature.

Therefore, the cycle can be operated efficiently by adjusting the control valve 5 in accordance with the signal S5 to obtain the necessary cooling capacity.

The composite output signal So of the composite calculation circuit 20 is the sum of the input signals, and this signal So is applied to the drive circuit 26, which generates the control signal Sc that drives the stepping motor 8 and controls the throttle of the control valve 5. The amount is determined according to the calculation result of the synthesis calculation circuit 20.

As described above, this device uses the amount of superheat as a basic parameter, and can prevent overload, prevent frost, and adjust cooling capacity by controlling the control valve 5.

It should be noted that the signals S 3 + S 4 + S 5 representing each parameter inputted to the synthesis calculation circuit 20 can be further changed according to the characteristics of the cycle, and the signals S 3 + S 4 + S 5 representing each parameter can be further changed depending on the characteristics of the cycle. (6) It is also possible to add PID control that takes into account the change in number So.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of an embodiment of the present invention, FIG. 2 is a block diagram showing the configuration of an electric control circuit, and FIG. 3 is a control characteristic diagram for explaining the operation. 1... J-press saucer, 2... capacitor, 5...
Control valve, 6... Evaporator, 15.16... Conversion circuit (first calculation means), 17... Subtraction circuit, 18...
・Conversion circuit, 19...Addition circuit, 20...Composition calculation circuit (second calculation means), 21.23...Comparator, 22゜24.25...Signal generator, 26...Drive circuit (driving means). Representative Patent Attorney Takashi Okabe (7)

Claims (1)

[Claims] In an air conditioner having a cycle in which refrigerant discharged from a compressor is circulated through a condenser, a control valve whose throttling amount is electrically controlled, and an evaporator, a first calculation means for calculating the amount of superheat in the evaporator of the cycle; a second calculation means that corrects the calculation result of the first calculation means based on other parameters related to the operation of the cycle; and generates a signal that controls the throttle amount of the control valve according to the calculation result of the second calculation means. An air conditioner comprising a drive means for.