JPS6185219A - Compressor control method - Google Patents

Abstract

PURPOSE:To improve cooling efficiency in an automotive air conditioning, by forming a compressor control system to decide a target value of a physical quantity related to the refrigerant pressure, depending on a physical quantity related to the air flow from a fan. CONSTITUTION:Signals from an air flow detector 34 and from a pressure sensor 35 are input to a control device 33. The control device 33 sets a target value of the refrigerant pressure by a signal from the detector 34, makes an electromagenetic valve 15 on or off to approach the target value, controls the discharge volume of the compressor 27, and controls the refrigerant pressure of the evaporator 31 output. This refrigerant pressure is monitored by the sensor 35, and if it is below a specific value, an electromagnetic clutch 36 is cut off causing the compressor 27 stopped. Thus, the cooling efficiency is improved, by setting a target value of a physical quantity related to the refrigerant pressure including the data related to the air flow.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a compressor used in an automobile type 5I device (air conditioner), and more particularly to a method for controlling the cooling capacity of a compressor with variable discharge capacity. It is.

[Prior Art] A conventional control method for a variable capacity compressor involves detecting the physical quantity 11 proportional to the degree of cooling of the evaporator, that is, the physical quantity m related to the refrigerant pressure in the evaporator, and comparing the physical quantity with a predetermined value of the physical quantity. A method is known in which the discharge capacity of a compressor is changed by comparing target values. And the predetermined target value of the above physical quantity is
For example, it is set according to the actual temperature inside the vehicle, the target temperature desired by the vehicle occupants, the cooling load amount calculated from the temperature outside the vehicle, etc. In this case, the air flow rate of the blower (hereinafter simply referred to as air flow rate) can be set manually by the vehicle occupant, or
Alternatively, it was automatically set by the control device according to the cooling load m. In addition, as seen in Japanese Patent Laid-Open No. 58-67517, it is possible to reduce the discharge capacity of the compressor and at the same time
A method of reducing ll has also been proposed. However, sending J! Conventionally, it has not been possible to set a predetermined target value for the above-mentioned physical property (2) by detecting the time interval.

[Problems to be solved by the invention] It is necessary to set a target value for the temperature of the blown air from the evaporator and bring the actual blown air temperature close to that target value (a method for controlling the discharge capacity of the compressor has been proposed). This is a preferable method because the temperature of the blown air is most closely related to the temperature inside the vehicle, but when applied to actual control, responsiveness to control becomes an issue.Therefore, the outlet of the evaporator is used as a physical quantity with good responsiveness. A refrigerant pressure of υ is considered, and there is a control method based on this pressure. However, it is possible to set a target value for this refrigerant UI force and control the discharge capacity of the compressor in order to bring the actual refrigerant pressure closer to the target value. In the jj method,
When there is a large amount of air passing through the evaporator, or when the temperature of the air passing through the evaporator is high, the temperature of the air blown from the evaporator may become higher than the desired Wl'ff. For example, when using an auto air conditioner to rapidly cool down the interior of a vehicle after driving one car, even if the air blower ■ is set to maximum, the refrigerant pressure target (11[+ However, since the humidity is constant, there is a problem in that it is difficult to reduce the humidity to the target humidity.

Furthermore, when the cooling load in the vehicle interior is low, such as during summer nights, the target value of the refrigerant pressure remains constant even if the air flow rate is at its minimum. As a result, the temperature of the air blown from the evaporator drops more than necessary, and there are cases in which energy is wasted, such as by heating this cold air with the heater 1a to reach the target temperature.

The present invention has been made in view of the above problems, and an object of the present invention is to solve the above problems and provide a method for controlling a compressor with a good cooling effect.

[Means for Solving the Problems] The present invention provides an evaporator that cools an air flow toward a vehicle interior, a feeder that sends the air flow to the evaporator, and a compressor that pumps refrigerant to the evaporator. and a capacity variable means provided in the compressor, which detects a physical difference related to the refrigerant pressure of the evaporator, and drives the capacity variable means to bring the physical value m closer to a predetermined target value. In the method of controlling the discharge capacity of the compressor, a physical quantity related to the flow rate of the air flow sent from the feeder is detected, and a target value between the physical quantities related to the refrigerant pressure is determined based on at least the physical quantity related to the flow rate. It is characterized by being

The compressor used in the control method of the present invention is equipped with means for varying the discharge capacity, such as a solenoid valve. The reason why the discharge capacity of the compressor is changed here is to make the cooling capacity variable, and the discharge capacity may be changed continuously, stepwise, or discontinuously. In addition, the compressor is driven by the engine used to direct the vehicle, and the rotation of the engine is transmitted to the compressor. It is desirable to have a clutch that For this clutch, an electromagnetic clutch or the like that is turned on and off by an electric signal is used.

The feeder 1111a used in the present invention is driven by a motor or the like, and sends air from inside or outside the vehicle to an evaporator for cooling. There are two types, axial flow type and centrifugal type, and both can be used. The feed ff1l is variable and desirably can be set arbitrarily by the vehicle occupant. It is also a preferable method to automatically control the feed and till using a computer or the like. Note that the amount of air blown may be changed continuously or may be changed in steps.

The physics related to the refrigerant pressure in the evaporator in the present invention relate to the cooling capacity of the refrigeration cycle, and include the refrigerant pressure at the evaporator outlet, the refrigerant pressure in the compressor suction pipe, the evaporator outlet air temperature,
Physical quantities such as the surface temperature of the fins of the evaporator and the surface temperature of the suction pipe of the compressor are used. Then, the physical ω target (1r1 is set by the occupant's lever operation or by a computer's control, etc.) based on the cooling load amount such as the vehicle interior temperature, vehicle exterior temperature, solar radiation layer, etc., and the target interior temperature desired by the vehicle occupant. .

Normally, the target value of the physical quantity m is compared with the actual value of the physical quantity to control the discharge capacity of the compressor. Control methods include those that use a pressure switch, those that use an electric circuit consisting of an amplifier and a comparator, and those that use a computer.

The flow-related physics group of the air flow from the blower referred to in the present invention is related to the driving state of the blower ff1tj1 at that time, and if the blower is of a type in which the terminal voltage of the motor is changed by a resistor, the position of the register, If a combination coater is used, a blower motor control signal etc. from a computer is used.

It is also possible to use the rotational speed of a motor or fan. Alternatively, the wind pressure of a blower may be used.

The feature of the present invention is that the above-mentioned air flow rate-related physics m is detected, and based on the detected value, the compressor output is controlled so as to follow the target refrigerant pressure value of the evaporator. .

In other words, if the outflow-related physical quantity is detected and the feed 11fB is large, the target value of the refrigerant pressure-related physics m is set to a value lower than the value set in a normal refrigeration cycle, and the feed 111fB is determined to be large.
When fl is small, the target value is set higher than the value set for normal freezing → noise. This pressure related item J
'J! The target value of ffl may be changed continuously or in stages. If it is an I4 structure in which the air blow n; changes continuously, it is desirable that the target value also be changed continuously.

Also, in a structure where the air blowing ■ changes in stages, it would be good to change the target value in stages.Also, only when the air flow is at its maximum, the target value for the refrigerant pressure-related item 3!r! lower than the value set in the refrigeration cycle, and only when it is at the minimum (
It is also possible to increase the vote value. By roughly detecting the temperature of the air sent from the blower to the evaporator or the temperature of the air blown out from the evaporator and combining it with physical quantities related to air flow rate, more detailed control is also possible. For example, if the temperature of the air being sent -8 degrees is below a certain value, the target value for the refrigerant pressure-related physics will not be lowered and will be kept at the normal freezing cycle value even if the air blowing m is at its maximum. It is also preferable to do so.

[Function] Fig. 1 shows an example of the method of the present invention, which is different from the conventional method in which the refrigerant pressure at the evaporator outlet is selected as the physics related to the refrigerant pressure in the evaporator, and the target value of the refrigerant pressure is kept constant regardless of the air flow rate. FIG. 2 is a diagram schematically showing changes in refrigerant pressure and evaporator air temperature during cool-down between the example of FIG. 1 and the case where the present invention is applied. In this case, the blower has a structure in which the blow 1!1ffi can be changed in three stages: 1-1-1iS and 10.

As shown in Fig. 1, when the present invention is applied (solid line), the target value of refrigerant pressure is lower than that of the conventional method in the case of air blowing flHi, so the actual refrigerant pressure is lower than that of the conventional method (broken line), and the target value is reached in a single time. The temperature of the blown air is as follows. In addition, in the conventional method for blowing air ff) LO, the target value of the refrigerant pressure is constant, so the cooling capacity of the compressor becomes excessive and the temperature of the blown air falls below the target value. The target value of high-frequency power has been increased, and the temperature of the blown air has been adjusted to an appropriate level.

[Example] This will be explained in detail in Examples below.

FIG. 2 is a system diagram of an air conditioner to which the control method of the first embodiment of the present invention is applied. The compressor 1127 is equipped with variable displacement means driven by the solenoid valve 15. This compressor 27
The structure of the variable capacitor will be explained based on FIGS. 3 and 4, and some schematic diagrams of the variable capacity will be explained based on FIG. 5.

Fig. 3 is a vertical cross-sectional view of the compressor 27, and Fig. 4 is the - - of Fig. 1.
■It is a sectional view. In Fig. 3.4, reference numeral 1 denotes a cylindrical housing that forms the outer shape of the compressor, and a cylindrical cylinder 2 is disposed inside this housing 1. A rotor 3 is provided. A front plate 4 is disposed on the front side end face of the cylinder 2 and the rotor 3, and a lever plate 5 is disposed on the rear side end face, and the front plates 1 to 4 and the cylinder 2, and the rear plate 5 and the cylinder 2 are fixed to each other by bolts 6.7. The rotor 3 is provided with two vane grooves 88 spaced apart by 90 degrees in the circumferential direction and passing through the center of the rotor, and the vane 8 is inserted into the vane grooves 88 so as to be freely movable. A working chamber A is defined by the vane 8, the inner wall of the cylinder 2, the front plate 4, and the rear plate 5. Further, a front shaft 3a is provided on the front end surface of the rotor 3.
is integrally formed, and a carrier shaft 3 is mounted on the rear end surface.
b is fixed with bolts 9.

The front shaft 3a is supported by the front plate 4 via a bearing 10, and the rear shaft 3b is supported by the support plate 5 via a bearing 11. A front housing 12 is disposed on the further front side of the front plate 4, and a rear housing 13 is disposed so as to surround the rotor 3, cylinder 2, and rear plate 5.

The front housing 12, the front plate 4, and the rear housing 13 are fixed to each other by bolts 14.

Further, a suction chamber B is formed by the front plate 4 and the front housing 12, a discharge IC is formed by the rear housing 13 and the cylinder 2, and an oil separation chamber is formed by the rear housing 13 and the rear brakes 1 and 5. There is. An oil separator 16 for separating oil in the discharged refrigerant is disposed in the oil separation chamber. Further, the rear housing 13 is provided with a discharge boat 26 for discharging the refrigerant discharged into the oil separation chamber to a condenser 28 of the refrigeration cycle. Note that the housing 2 is provided with a discharge passage 17 for guiding refrigerant from the working chamber A to the discharge chamber C, and the freon 1 to plate 4 are provided with suction passages 25 for sucking refrigerant from the suction chamber B. It is provided.

As shown in FIGS. 4 and 5, the front plate 4 is provided with a bypass hole 18 to communicate the working chamber A and the suction chamber B, which have entered the stage of volume reduction. The plunger 2 serves as a bypass valve that opens and closes the bypass hole 18.
0 is provided on the front plate 4. By returning the refrigerant sucked into the cylinder 2 to the low pressure side without compressing it through the bypass hole 18, capacity control is performed.

A schematic diagram of the capacity control mechanism is shown in FIG. Compressor high pressure side 2
The high-pressure refrigerant that can be led from 1a is divided into two parts: one goes from the high-pressure side 21a to the plunger back chamber 21, and the other goes through the electromagnetic valve 15 and goes to the low-pressure side 21b. Here, only when the solenoid valve 15 is turned on, the high pressure side 21a communicates with the low pressure side 21b. The pressure in the plunger back chamber 21 is controlled by turning the electromagnetic valve 15 ON-OFF and controlling the flow rate of the high-pressure refrigerant from the high-pressure side 21a to the low-pressure side. Then, the plunger 2o is stopped at an arbitrary position by balancing the pressure with the spring 24,
By changing the area of the bypass hole 18, the discharge capacity of the compressor is continuously changed.

This Wl! I-valve 15 (7) ON-OFF 1llllll
[Controlled by computer in R33.]

In FIG. 2, the compressor 27 configured as described above compresses the refrigerant gas sent from the evaporator 31 to the condenser 28.
send to The refrigerant gas is cooled by air m in the condenser 28 to become a high-pressure liquid, and impurities are removed in the receiver 29 and sent to the expansion valve 30. The refrigerant, which has become a low-pressure mist in the expansion valve 30, is vaporized in the evaporator 31 by the airflow from the blower 32, whose air flow rate is manually switched to three levels, and is then vaporized by the evaporator 31. Sent.

In the refrigeration cycle configured in this way, the control device 33 operated by the automobile battery sends ff1
f! NI! by signals from the level detection device 34 and pressure sensor 35! Valve 15 and N! 1 clutch 36 is controlled. That is, normally the control device 33 turns on the solenoid valve 15.
The pressure sensor 35 is monitored so that the refrigerant pressure at the outlet of the evaporator 31 reaches the target value by controlling the discharge capacity of the compressor 27 by turning OFF, but when the refrigerant pressure falls below a certain value, the electromagnetic clutch 36 and stop the operation of the compressor 27. When the air blow m is changed, the control unit [33 changes the target value of the refrigerant pressure based on the signal from the level detection bag 34, and controls the compressor 27 via the solenoid valve 15 so that the target value is reached. Control the discharge volume. Control I device 3
3 has a built-in micro combi coater.

FIG. 6 shows a flowchart of the main part of the control contents of the control device 33.

In step 101, a target value pso of the refrigerant pressure, a reference refrigerant pressure Pm when the maximum airflow is set to Me, and a set value Pc of the refrigerant pressure for turning off the electromagnetic clutch 36 are determined from the cooling load amount, the target vehicle interior temperature, etc. In step 102, it is determined whether or not there has been a change in the amount of air blown. If there is no change in the amount of air blown, the process proceeds to step 107 without changing the target value Pso. If there has been a change or when the compressor 27 starts operating, the process proceeds to step 103. The level of the amount of air blown is determined.

If the air flow rate is Hi, the target value pso of the refrigerant pressure is set to a value lower than PIll by ΔP in step 104, and the air flow rate is set to 1.
! If! If l is Lo, Pso is P in step 106.
The value is set to be higher than m by ΔP+.

Further, when the transmission Ill is Me, PsO becomes pm in step 105. In these cases, the values of ΔP+ and ΔP2 are mainly determined by the amount of cooling load, and although they may be constant values, they are preferably values proportional to the cooling load m.

In step 107, the actual refrigerant pressure P is input from the pressure sensor 35, and in step 108, the clutch 36 is turned off.
It is compared with the clutch engagement/disengagement setting pressure Pc. pc＞
In the case of p, that is, when the actual refrigerant pressure is lower than Pc, in order to prevent frosting of the evaporator 31 and to prevent unnecessary driving of the compressor 27, the clutch 3 is closed in step 110.
6 is turned OFF, the clutch engagement setting pressure pc increases by a minute value ΔX, and control of the discharge capacity of the compressor 27 is unnecessary, so the process returns to step 101. P in step 108
If C≦P, it is necessary to drive the compressor 27, so the clutch 36 is turned on in step 109, and PC becomes a minute value Δ.
X number will decrease. Note that the above-mentioned ΔX is a minute value that is the width of the hysteresis loop.

Steps 111 to 113 show processing related to control of the discharge customer group of the compressor 27. In step 111, the target value Pso of the refrigerant pressure is compared with the actual refrigerant pressure detected in step 107. If pso>P, it is determined that the cooling capacity is excessive, and in step 113, the solenoid valve 15
is turned on, lowering the pressure in the plunger back chamber 21 and reducing the discharge capacity. Then, pc increases by ΔY. P
If SO≦P, it is determined that the cooling capacity is insufficient.

Then, in step 112, the N11 valve 15 is turned off, the pressure in the plunger back chamber 21 increases, and the discharge capacity increases. Further, pso is decreased by ΔY and the process returns to step 101. This ΔY is a minute value that becomes the width of the hysteresis loop, similar to the above-mentioned Δ×.

The above control method allows smooth air conditioning control.

FIG. 7 shows a system diagram of an air conditioner to which the control method of the second embodiment of the present invention is applied. As is clear from a comparison between FIG. 2 and FIG. 7, the configuration of the air conditioner to which the second embodiment is applied is the same as that of the first embodiment except that a temperature sensor 46 for detecting the temperature of the air blown from the evaporator 41 is provided. The configuration is the same as that of an air conditioner to which the control method is applied. Also, the capacity variable means of the compressor 37 is the same as in the first embodiment, as shown in FIGS. 3, 4, and 5. In other words, in this embodiment, the temperature sensor 4
6 detects that the air blown from the evaporator 41 > Q O,
The target value of the refrigerant pressure is set using this value and the air flow m, and the discharge capacity of the compressor 37 is controlled.

FIG. 8 shows a control device 43 according to a second embodiment of the present invention.
2 shows a flowchart of the main parts of the control contents.

In step 201, the target value Pso of the refrigerant pressure, the reference refrigerant pressure Pm when the sending ms is Me, the first set temperature TI of the evaporator outlet air temperature, the second set temperature degree T2 and a third set temperature T3 are set. Here, each temperature has a relationship of T,>T2>T3,
T1 and T2 are the target values of the blowing air temperature for setting the target value of the refrigerant pressure along with the feed 1!1■, and T3
is the target value of the blown air temperature at which the electromagnetic clutch 48 is turned off. In step 202, the actual temperature T of the blown air from the evaporator 41 and the refrigerant pressure P at the outlet of the evaporator 41 are detected by the temperature sensor 46 and the pressure sensor 45 and input into the computer of the control device 43. In step 203, it is determined whether or not there has been a change in the air blow rate ff1fFt. If there is no change in the air blow rate, the process proceeds to step 210 with the target value pso unchanged. If there has been a change or when the compressor 37 starts operating, it is determined in step 204. send yam
level is determined.

Send J! If tin is 1-1+, the second set lagoonal degree T2 and the actual blowing temperature T are compared in step 205. If T2≦T, it is determined that the cooling capacity is insufficient, and in step 207, the PSO is set to a value lower than pm. ps at 208.

is assumed to be pm. If the air flow rate is LO, step 206
At , the first set temperature T+ and the actual blowing temperature T are compared. If T1≧T, it is determined that the cooling capacity is excessive, and the process proceeds to step 209.

is considered to be a chain that is higher by PmJ:SΔP1, and if T+<T, it is determined that the cooling capacity is insufficient, and pS is set at step 208.
O is assumed to be PIIl. Furthermore, when the air flow rate is Me, the PSO is set to l)m in step 208.

In these cases, the values of Δ[]1 and ΔP2 are determined by the cooling load amount, as in the first embodiment.

Next, in step 210, the third set temperature T3 and the actual blowing temperature T are compared, and if T3>T, the evaporator 41
In order to prevent frost and unnecessary driving of the compressor 37, the clutch 48 is turned off in step 213, and the process returns to step 201. If T3≦T, the compressor 37
It is necessary to drive the clutch 48, and the clutch 48 is turned on in step 211. At step 212, the same process as the flow from step 111 to step 113 of the first embodiment is performed, and the actual tax refrigerant pressure P input at step 202 is
The solenoid valve 47 is turned ON-OFF to control the discharge capacity of the compressor 37 so that it approaches the target value pso that draws a hysteresis loop, and the process returns to step 201.

The above control method allows the air conditioner according to this embodiment to operate smoothly.

[Effects of the Invention] According to the control method of the present invention, a target value between refrigerant pressure-related physics for varying the compressor discharge capacity (1) is set including any relation to the amount of air blown. Therefore, for example, if the transmission is set to 1i1111@-maximum during the cool-down period in the vehicle interior after parking in the summer, the object 1! [! The target value of 111 is lowered to increase the cooling capacity and therefore reach the target room temperature faster. In addition, when the air conditioning load is small (such as during nights in spring, autumn, or summer) and the air flow is at its minimum, the target value of the physical quantity increases to prevent unnecessary drive of the compressor and save power. It also shows excellent effects.

[Brief explanation of the drawing]

FIG. 1 is a diagram schematically showing changes in refrigerant pressure and blown air temperature depending on air flow m and time. Figures 2, 3, 4, 5, and 6 are diagrams relating to the first embodiment of the present invention, with Figure 2 being a system diagram of the empty wA device, and Figure 3 being used. Fig. 4 is a cross-sectional view taken along the line ■-■ in Fig. 3, Fig. 5 is an explanatory diagram schematically showing the capacity control tiI mechanism, and Fig. 6 is the processing details of the control device used. It is a flowchart which shows. 7 and 8 are diagrams according to a second embodiment of the present invention,
FIG. 7 is a system diagram of the air conditioner, and FIG. 8 is a flowchart showing the processing of the control device used. 27.37... Compressor 31.41... Evaporator 3
3.43...Control device 32.42...Blower 15
．． 47...Solenoid valve patent applicant 1 Agent for Nippondenso Co., Ltd.
Patent attorney Mamoki Okawa Patent attorney Original author Shudo Patent attorney Akio Maruyama Yabu

Claims (4)

[Claims] (1) An evaporator that cools the air flow toward the vehicle interior, a blower that sends the air flow to the evaporator, a compressor that pumps refrigerant to the evaporator, and a capacity variable means provided in the compressor. In the method of controlling the discharge capacity of the compressor by detecting a physical quantity related to the refrigerant pressure of the evaporator and driving the capacity variable means to bring the physical quantity close to a predetermined target value, the blower 1. A compressor control method, comprising: detecting a physical quantity related to the flow rate of an air flow sent from a compressor; and determining a target value of the physical quantity related to refrigerant pressure based on at least the physical quantity related to the flow rate. (2) The compressor control method according to claim 1, wherein the target value of the physical quantity related to refrigerant pressure is determined by the physical quantity related to the flow rate of the air flow from the blower and the temperature of the air flow. (3) The target value of the physical quantity related to the refrigerant pressure is lowered when the physical quantity related to the air flow rate is large, and the target value between the physical quantities related to the refrigerant pressure is increased when the physical quantity related to the air flow rate is small. Compressor control method according to item 1. (4) The compressor control method according to claim 1, wherein the physical quantity related to the refrigerant pressure is the refrigerant pressure in the evaporator.