JPH0338136B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a refrigeration cycle control device used for air conditioning of automobiles and the like.

[Conventional technology]

2. Description of the Related Art Conventionally, as a control device for an air conditioner for an automobile, the one described in, for example, Japanese Patent Laid-Open Publication No. 118547/1983 is known. In this device, when the outside temperature is above a certain value, the cooling capacity is switched between high and low capacity depending on the room temperature, and when the outside temperature is below a certain value, the cooling capacity is switched between low capacity and the compressor is stopped depending on the room temperature. That's what I do.

[Problem to be solved by the invention]

However, in this conventional system, since the cooling capacity is changed according to the room temperature, there is a problem in that the control cannot accurately follow the actual capacity of the refrigeration cycle. In addition, in this conventional system, the temperature at which switching between small capacity and compressor operation is stopped when the outside temperature is below a predetermined temperature, and the temperature at which switching between large capacity and small capacity when the outside temperature is above a predetermined temperature, are constant. I was getting used to it. That is, by simply switching between small capacity and zero capacity, and between large capacity and small capacity, the room temperature controlled thereby always remained constant. Therefore, it has not been possible to switch and control the actual capacity of the refrigeration cycle. Furthermore, since the room temperature at which the compressor is switched on and off and the capacity is switched is changed depending on the outside temperature, there is also the problem that power saving control cannot be performed in accordance with the driver's requests.

The present invention has been made in view of the above problems, and
It is an object of the present invention to provide a refrigeration cycle control device that can perform control that accurately follows the capacity of a refrigeration cycle by changing the degree of cooling of an evaporator.

In particular, it is an object of the present invention to achieve power-saving operation of an air conditioner by controlling the capacity of a refrigeration cycle to be varied. Another object of the present invention is to enable switching between power-saving operation and normal operation according to the driver's request by manually switching control set values.

In order to achieve the above object, in the present invention,
A sensor that detects the temperature or refrigerant pressure related to the degree of cooling of the evaporator of the air conditioner is used, and an input signal from the sensor is received to control both the intermittent operation of the electromagnetic clutch and the variable displacement of the compressor. Adopt a control device.

Further, a control set value switching means is provided for manually changing at least one of the discontinuation point of the electromagnetic clutch and the discharge capacity change point of the compressor. In particular, the electromagnetic clutch discontinuation point before switching by this switching means and the discharge capacity change point after switching are configured so as not to coincide.

[Effect]

In the present invention configured as described above, by manually turning on the control set value switching means by the passenger, at least one of the control set values that determines the discontinuation point of the electromagnetic clutch and the control set value that determines the point at which the discharge capacity of the compressor is changed. You can switch between the two at will. Therefore, passengers can freely switch the capacity of the refrigeration cycle based on their own sense of coldness, and can experience a sense of power savings. In addition, the control device receives an input signal from a sensor that senses the temperature or refrigerant pressure related to the degree of cooling of the evaporator, and controls the on/off of the electromagnetic clutch and the discharge capacity of the compressor in accordance with the input signal. Compared to a system that switches the cooling capacity according to the room temperature, control can be performed according to the degree of cooling.

Therefore, for example, when it is decided to change the intermittent setting value of the electric fan, the compressor, which was operating at a large capacity or a small capacity before the change, can be stopped by switching the switching means.
Further, for example, when it is decided to change the discharge capacity change point of the compressor, the compressor, which was operated at a large capacity before the change, can be switched to a small capacity operation.

In particular, in the present invention, the switching means differs between the setting value for electromagnetic clutch engagement and disengagement before the change and the setting value for changing the discharge capacity after the change. The capacity of the refrigeration cycle is controlled in an organic manner and more precisely.

Here, since the present invention controls the capacity of the refrigeration cycle itself, the response of the control is better than that of the conventional technology which controls the room temperature, and accordingly, the power saving effect can be more effectively exhibited.

〔Example〕

Next, a first embodiment of the present invention will be described. A first embodiment is shown in FIG. The automotive refrigeration cycle control device of this embodiment includes a variable capacity compressor 1 that compresses gas refrigerant to high temperature and high pressure, a condenser 2 that converts the high temperature and high pressure gas refrigerant into liquid refrigerant, a receiver 3 that receives the liquid refrigerant, and a receiver 3 that converts the liquid refrigerant to a low temperature. It has a refrigeration cycle consisting of an expansion valve 4 that expands the refrigerant into a low-pressure mist, and an evaporator 5 that removes heat from the surrounding air when the mist refrigerant evaporates into gas. A blower fan 7 is disposed upstream of the air passage 6 in which the evaporator 5 of this refrigeration cycle is installed, and blows cooled air around the evaporator 5 into the vehicle interior (not shown). For example, a thermistor 8 is attached to the blowout side as a sensor for sensing the air blowout temperature immediately after the evaporator.

9 is an electromagnetic clutch that transmits the driving force from the automobile engine 14 to the compressor 1. For example, in the case of a vane type compressor, the compressor 1 includes a variable capacity member consisting of a small hole that changes an operating space (not shown) to a large capacity, an on-off valve (not shown) for the small hole, and a solenoid valve 10 that drives this on-off valve. Built-in.

The electromagnetic clutch 9 and the electromagnetic valve 10 are
It is driven by the output signal of the control device computer 11. Further, the computer 11 is connected to the thermistor 8 described above and a manual switch (economy switch) 12 as a control set value switching means for changing the set temperature stored inside the computer 11. Note that the manual switch 12 is mounted on an operation panel of an air conditioner provided in the driver's seat of the automobile.

FIG. 2 is a flowchart showing an example of the program of the control device of this embodiment. The operation of the present invention will be explained below along with this flowchart. At start 15, when the main switch (not shown) of the automobile air conditioner is turned on, the program inside the control device starts. In the next initial set step 16, to prevent the compressor 11 from operating abnormally,
All input signals are turned off, and the operating output signal of the compressor 1 is in the state where the electromagnetic clutch 9 is turned off. In the next step 17, the air temperature T at the outlet of the evaporator 5 is
The analog signal is converted by the thermistor 8 into a digital signal by an AD converter (not shown) inside the computer 11 and stored in a storage device (not shown) inside the computer 11.
The opening/closing signals of No. 2 are also stored in the storage device. When the process proceeds to step 18, it is determined whether the manual switch 12 is on or off, and if the manual switch 12 is off, the process proceeds to step 19. In step 19, when the outlet air temperature T is below the small capacity switching temperature _T1 , a signal is output to turn off the electromagnetic clutch 9, and the electromagnetic clutch 9 is turned off via a drive circuit (not shown).
Compressor 1 stops. Also, the outlet air temperature T
If T is higher than ₁ , proceed to step 20. step 20
Then, the outlet air temperature T and the large capacity switching temperature _T2 are compared and judged, and if _T1 <T≦ _T2 , the process proceeds to step 24 and outputs a control signal to set the discharge capacity of the compressor 1 to 50%, not shown. The solenoid valve 10 is closed via the drive circuit, and the compressor 1 operates at 50% capacity. T＞
When T ₂ ', the process proceeds to step 25 and a control signal is outputted so that the discharge capacity of the compressor 1 becomes 100%.
The solenoid valve 10 is closed via a drive circuit (not shown), and the compressor 1 operates at 100% discharge capacity.

Next time the manual switch 12 is turned on, the step
The process proceeds to step 21, where the small capacity switching temperature _T3 is compared with the outlet air temperature T, and if T≦ _T3 , the process proceeds to step 23, where a control signal is output to turn off the electromagnetic clutch 9. If T > T ₃ , proceed to step 22. In step 22, the large capacity switching temperature _T4 is compared with the outlet air temperature T, and if _T3 <T≦ _T4 , step 24 is performed.
The process proceeds to step 25 and outputs a control signal to make the discharge capacity of compressor 1 50%, and when T>T ₄ , the process proceeds to step 25 and outputs a control signal to make the discharge capacity of compressor 1 100%. .

As described above, the computer 11 compares each temperature setting with the outlet air temperature, turns off the electromagnetic clutch 9 (step 23), sets the discharge capacity of the compressor 1 to 50% (step 24), and sets the discharge capacity of the compressor 1 to 50% (step 24). capacity 100
% (step 25), the process returns to step 17, stores the input state at that time, and repeats the aforementioned control.

Above small capacity switching temperature T ₁ , large capacity switching temperature T ₂
The temperature setting determined by the small capacity switching temperature T ₃ and the large capacity switching temperature T ₄ is shown in FIG. 3, and the temperature setting determined by the small capacity switching temperature T 3 and the large capacity switching temperature T 4 is shown in FIG. That is, the values of the small capacity switching temperature T ₃ and the large capacity switching temperature T ₄ are T ₃ ≧
Can be set freely under the conditions of T ₁ and T ₄ > T ₂ . For example, Fig. 4 shows the case where the small capacity switching temperature T ₃ = T ₁ and the large capacity switching temperature T ₄ > T ₂ , and Fig. 5 shows the case where the set temperature range is T ₃ > T ₁ , T ₄ > T _2. This is the case when That is, in the temperature setting shown in FIG. 5, the temperature at which the compressor 1 stops operating is set higher than the temperature setting shown in FIG. 4. Further, as another embodiment of the first invention, the temperature setting may be changed in several stages by switching the manual switch 13. For example, the computer 11 may have a dial that has several different resistance sections and can be switched between several stages, and several temperature settings stored inside the computer 11 corresponding to each stage of the dial switch. When the dial is switched to a certain level, the corresponding temperature setting is changed, and the compressor 1 can be controlled in discharge capacity according to the changed temperature setting.

Further, by continuously changing the resistance value of a dial having a continuously variable resistance section, it is also possible to continuously change the temperature setting. That is, for example, in the first embodiment, the small capacity switching temperature T _S is set from T ₁ to T ₃ and the large capacity switching temperature T _L
It is possible to change the temperature to any temperature between T ₂ and T ₄ and control the capacity of the compressor 1 based on the changed temperature.

Next, a second embodiment of the present invention will be described. FIG. 6 shows this embodiment. In addition to the manual switch 12 which is the control set value switching means in the first embodiment, the computer 11 that controls the capacity variation of the compressor 1 is also equipped with a manual switch 12 that controls the ambient temperature of the vehicle. A temperature sensor 13 attached to the front grill of a car, for example, is connected to the computer 11 to sense the outside air temperature (hereinafter referred to as outside temperature). The temperature setting is configured to determine the point at which the discharge capacity is changed.

The rest of the configuration is the same as that of the first embodiment shown in FIG. 1, so a description thereof will be omitted.

FIG. 7 is a flowchart showing the control of the second embodiment. The start (step 38) and initial set (step 39) are the same as steps 15 and 16 in FIG. 2, so their explanation will be omitted. In step 40, the outlet air temperature T, the outside air temperature, and the reference temperature _T
The signal is converted into a digital signal by a converter and stored in a storage device (not shown) inside the computer 11, and the open/close signal of the manual switch 12 is also stored in the storage device. Next, in step 41, it is determined whether the manual switch 12 is open or closed, and the manual switch 12 is opened or closed.
If it is off, the process advances to step 42 and step 43, and the outlet air temperature T is set to the small capacity switching temperature T ₁ shown in FIG.
Determine which range of temperature setting the large capacity switching temperature _T2 is in, and depending on the result, turn off the electromagnetic clutch 9 (step 49), set the discharge capacity of the compressor 1 to 50% (step 50), or turn off the compressor 1. Discharge capacity 100% (step
51). Manual switch 1
If 2 is on, proceed to step 44. step 44
performs a correction judgment on the temperature setting for controlling the discharge capacity of the compressor 1 based on the outside air temperature. In other words, when the outside temperature is higher than the reference temperature _T0 , step 47;
Proceed to step 48, and as shown in FIGS. 4 and 5, the small capacity switching temperature T ₃ (T ₃ ≧T ₁ ) and the large capacity switching temperature T ₄ (T ₄
> _T2 ) and the outlet air temperature T, and depending on the result, the electromagnetic clutch 9 is turned off (step 49), the discharge capacity of the compressor 1 is set to 50% (step 50), and the Discharge capacity 100% (step 51)
Outputs a control signal to In addition, when the outside air temperature is below the reference temperature _T0 , step 45 and step
46, and as shown in Figures 8 and 9, the small capacity switching temperature T ₅ (T ₅ ≧T ₃ ) and the large capacity switching temperature T ₆ (T ₆ > T ₄ )
Compare and judge the temperature setting and the blowing air temperature T, and depending on the result, turn off the electromagnetic clutch 9 (step
49), outputs a control signal to set the discharge capacity of the compressor 1 to 50% (step 50) and to 100% (step 51).

After performing the processing in steps 49, 50, and 51, the process returns to step 40, stores the next input state, and repeats the aforementioned control.

The value of the set temperature is, for example, T ₁ =3°C, T ₂
= 4℃, T ₃ = 6℃, T ₄ = 7℃, T ₅ = 7℃, T ₆ =
8°C, T ₀ =10-15°C.

In addition, the small capacity switching temperature T ₅ and the large capacity switching temperature T ₆
The value of can be freely set within the range of T ₅ ≧ T ₃ and T ₆ > T _4. With the temperature setting shown in Fig. 9, the temperature at which the compressor 1 stops operating is higher than the temperature setting shown in Fig. 8. It is set.

Furthermore, by using a manual dial that can be switched in several stages instead of the manual switch 12 and combining it with outside temperature correction, it is also possible to continuously change several different temperature settings.

In addition, in the first and second embodiments described above, the air temperature immediately after the evaporator is sensed and controlled, but the refrigerant pressure inside the evaporator, the refrigerant temperature, or the temperature of the evaporator fin or refrigerant piping is controlled. Surface temperature, etc. may also be used.

Furthermore, in the second embodiment, the outside air temperature sensor 13
is installed on the suction side of the evaporator 5 in the air passage 6,
The intake air temperature may also be sensed.

In the present invention, 50% capacity is used for explanation as the compressor small capacity, but other capacities, for example 40% capacity, may also be used.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to accurately follow the capacity of the refrigeration cycle, and to change control set values according to the demands of the driving vehicle, thereby achieving improved power saving. It has this excellent effect.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the overall control system of the first embodiment of the present invention, FIG. 2 is a flowchart showing the operation of the computer in the first embodiment, and FIG.
The figure is a conventional compressor operating characteristic diagram, Figures 4 and 5 are compressor operating characteristic diagrams when changing the set temperature in the first and second embodiments, and Figure 6 is a compressor operating characteristic diagram of the second embodiment. A configuration diagram showing the overall control system, Fig. 7 is a flowchart showing the operation of the computer in the second embodiment, and Figs. 8 and 9 are compressor operating characteristics when changing the set temperature in the second embodiment. It is a diagram. DESCRIPTION OF SYMBOLS 1... Compressor, 5... Evaporator, 8... Thermistor showing an example of a refrigerant temperature sensor, 9... Electromagnetic clutch, 10... Solenoid valve of variable capacity member, 11...
. . . A computer as a control device, 12 . . . A manual switch that is an example of a control setting value switching means, 13 . . .
...Temperature sensor, 14...Engine.

Claims (1)

[Scope of Claims] 1. A compressor that receives the driving force of an automobile engine via an electromagnetic clutch and has a variable discharge capacity member, and a sensor that senses the temperature or refrigerant pressure related to the degree of cooling of the evaporator. a control device that receives an input signal from the sensor and sends a drive output signal to a variable displacement member of the compressor for disengaging the electromagnetic clutch; and a control set value that determines at least a disengagement point of the electromagnetic clutch; 1. A refrigeration cycle control device for an automobile, comprising: control set value switching means for manually changing one of the control set values that determines a discharge capacity change point.