JPH0429101Y2 - - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] (Field of industrial application) The invention is used for automotive cooling cycles,
The present invention relates to a control device for a variable capacity swash plate compressor capable of changing the internal volume of a compression chamber.

(Prior Art) FIG. 6 is a diagram showing a cooling cycle 1 used in a general automobile air conditioner. When a compressor 3 is driven by an engine (not shown) via a belt, a pulley 2, and a magnetic clutch 2a, the compressor 3 adiabatically compresses the gaseous refrigerant to a high temperature and high pressure, and supplies the gaseous refrigerant to a condenser 4. In this condenser 4, the refrigerant is cooled by exchanging heat with external air, and becomes a high-pressure liquid refrigerant.
The refrigerant that has passed through the liquid tank 5, which temporarily stores this liquid refrigerant and removes moisture and dust from the refrigerant,
The refrigerant is throttled and expanded in the expansion valve 6 and flows into the evaporator 7 as a low-pressure mist of refrigerant. As a result, the air flowing into the vehicle interior is cooled by the evaporator 7 and becomes cold air, thereby cooling the vehicle interior.

When the cooling cycle 1 is activated, it has the effect of dehumidifying the air flowing into the vehicle interior, so the cooling cycle 1 can be used not only in the summer but also in the spring.
It is designed to operate even in autumn and winter. In the normal compressor 3, compressor 3
The amount of refrigerant discharged per rotation of the rotor portion is always constant, and the amount of refrigerant flowing into the evaporator 7 is controlled by the expansion valve 6 according to the heat load. In order to prevent the condensed water adhering to the outer surface of the evaporator 7 from freezing, if the outer surface of the evaporator 7 falls below a predetermined temperature, a thermoswitch 8 and an amplifier 9 are used to turn off the compressor 3. I'm trying to stop it. Therefore, when the outside air temperature is low and the heat load on the evaporator 7 is small, such as in the winter, the compressor 3 is turned on and off more frequently by the clutch 2a than when the heat load is large, such as in the summer. will be repeated. As a result, the power consumption is obtained from the engine in accordance with the heat load of the evaporator, that is, the heat load of the cooling cycle (hereinafter referred to as "cycle load"), thereby achieving fuel efficiency.

However, in such a conventional compressor 3, the amount of refrigerant discharged per revolution is always constant, so the compressor must also rotate at high revolutions, especially when the engine speed is high. However, it becomes difficult to control the refrigerant flow rate according to the cycle load using only the expansion valve, and the power consumption for driving the compressor has to increase.

Therefore, recently, as the compressor 3 used in such a cooling cycle 1, the
A variable capacity swash plate type compressor having a structure shown in Japanese Patent No. 158382 has been proposed. In this variable capacity swash plate type compressor, the stroke of the piston in the cylinder is changed in accordance with the suction pressure of the compressor, so that the discharge amount of the compressor per rotation of the rotor is changed. Therefore, in such a variable capacity compressor, a desired amount of refrigerant depending on the cycle load is circulated within the cooling cycle while the suction pressure of the compressor is kept constant.

According to such a variable capacity compressor, for example, when the outside air temperature is low and the heat load is small, but when the cooling cycle 1 is operated to perform dehumidification in the evaporator 7, the refrigerant flowing through the entire cooling cycle 1 is Since the amount of refrigerant is small, the evaporation pressure of the refrigerant in the evaporator 7 is prevented from becoming too low due to excessive throttling in the expansion valve 6. Therefore, it is possible to avoid a so-called freezing phenomenon of the evaporator 7 at low load, which causes the condensed water in the evaporator 7 to freeze, and therefore a thermoswitch or the like to prevent this is not necessary.

Further, even when the outside air temperature is high and the heat load is large, the capacity of the compressor changes accordingly, and as a result, power consumption in the capacity control region can be reduced.

(Problem to be solved by the invention) However, in the case of such a variable capacity swash plate type compressor, the cooling cycle of the automobile in which the compressor is installed immediately after the vehicle has been parked for a long time under the scorching sun in the summer, etc. When the engine is started, the cool-down performance (the rate of decrease in the cabin temperature per unit time immediately after the engine starts) is poor, and it takes a long time to cool the cabin to a comfortable temperature. Ta. This is due to the fact that in conventional control devices for variable capacity swash plate type compressors, the suction pressure of the compressor is controlled to be constant even when rapid cooling is required.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide a control device for a variable capacity swash plate compressor that contributes to energy saving and has good cool-down performance.

[Structure of the invention] (Means for solving the problem) In order to achieve the above object, the present invention integrates a plurality of pistons, which are mounted in a cylinder block so as to be able to reciprocate in the axial direction, into a drive shaft. The piston is rotated and reciprocated by a driving swash plate attached so that its inclination angle can be changed, and the pressure in the compression chamber formed in front of the piston and the pressure in the crank chamber formed in the rear of the piston are adjusted. In the variable capacity swash plate type compressor, the stroke of the connecting piston is changed by changing the inclination angle of the drive swash plate according to a change in the differential pressure of the variable capacity swash plate type compressor. a cycle load detection means for detecting; a cycle load comparison means for comparing whether the cycle load detected by the cycle load detection means is a predetermined value or more; and a cycle load comparison means for detecting the temperature of the actual air cooled and blown out by the cooling cycle. a target blowout temperature detection means for detecting a target blowout temperature of air cooled by the cooling cycle; and a temperature detected by the blowout temperature detection means and a target temperature detected by the target blowout temperature detection means. and a crank chamber pressure control means for changing the pressure in the crank chamber according to output signals from the outlet temperature comparing means and the cycle load comparing means, When the temperature difference compared by the comparison means is equal to or higher than a predetermined temperature, the crank chamber pressure is controlled preferentially by the crank chamber pressure control means based on the output signal from the blowout temperature comparison means. shall be.

(effect) Next, the operation of the present invention will be explained based on FIG.

First, the thermal load acting on the evaporator in the cooling cycle is detected as a cycle load by the cycle load detection means 70. at the same time,
The blowout temperature detection means 73 detects the temperature of the air blown into the vehicle interior, and the target temperature detection means 74 detects the target blowout temperature. Next, the temperature difference between the temperatures detected by the outlet temperature detecting means 73 and the target outlet temperature detecting means 74 is compared and calculated by the outlet temperature comparing means 75. If this temperature difference is higher than a predetermined temperature, rapid cooling is required, so the crank chamber pressure control means 72 adjusts the pressure in the crank chamber to maximize the stroke of the reciprocating piston, thereby reducing the load. Maximize the compressor's discharge rate in order to flow the appropriate refrigerant flow rate into the cycle.

Furthermore, when the temperature difference calculated by the blowout temperature comparison means 75 is less than or equal to a predetermined temperature, the crank chamber pressure control means is controlled in accordance with the output signal of the cycle load comparison means 71. This cycle load comparison means performs a comparison calculation to determine whether the cycle load detected by the cycle load detection means 70 is equal to or greater than a predetermined value. If the cycle load calculated by the cycle comparison means 71 is equal to or higher than a predetermined value, it is considered that a large load is acting on the cooling cycle, so in this case, the crank chamber pressure control means 7
Step 2 adjusts the pressure in the crank chamber, increases the stroke of the reciprocating piston, and flows the appropriate amount of refrigerant into the cycle in response to the heavy load. Also,
If the cycle load calculated by the cycle comparison means 71 is less than or equal to the predetermined value, it is considered that the heat load acting on the cooling cycle is relatively small. The refrigerant pressure is controlled, the stroke of the reciprocating piston is reduced, and an appropriate flow rate of refrigerant is allowed to flow within the cycle in accordance with the small heat load.

(Example) Examples of the present invention will be described below.

Figure 1 is a block diagram showing the configuration of the present invention;
The figure is a schematic configuration diagram of a variable capacity swash plate compressor and its control device according to an embodiment of the present invention, and FIG. 3 is a flowchart showing the operation of the embodiment.
4A to 4C are schematic sectional views of a variable capacity swash plate type compressor according to the same embodiment, and FIGS. 5A and 5B are graphs showing control characteristics according to the same embodiment, which are common to the members shown in FIG. 6. The same reference numerals are used to denote the same members, and some explanations thereof will be omitted.

As shown in FIGS. 2 and 4, the variable capacity swash plate compressor 50 according to this embodiment includes a cylinder block 24, a crankcase 17 attached to the rear end of the cylinder block 24, and a crankcase 17 attached to the tip of the cylinder block 24. The compressor body 10 includes a head 30. For example, five pistons 23 are mounted within a cylinder 25 formed in the cylinder block 24 so as to be able to reciprocate in the axial direction. On the other hand, a crank chamber 12 is formed in the crankcase 17, and a drive rod 11a is fixed to the drive shaft 11, which is rotatably supported by the cylinder block 24 and the crankcase 17.
A drive swash plate 13 is mounted within the crankcase 12 so as to be rotatable about a pin 11b.
Therefore, this drive swash plate 13 rotates together with the drive shaft 11, and also rotates together with the drive shaft 11.
The angle of inclination relative to the base is freely variable.

A non-rotating wobble plate 16 is in contact with the drive swash plate 13 through a thrust bearing 14 at its radial end surface and a radial bearing 15 at its inner peripheral surface. The angle changes as the inclination angle changes. The movement of the non-rotating wobble plate 16 in the thrust direction is regulated by a thrust washer 20 and a snap spring 21. The non-rotating wobble plate 16 is connected to a shoe 19 slidably connected to a guide pin 18 fixed to a casing 17.
Rotation is prevented and movement in the direction of the drive shaft 11 is guided.

The piston 23 and the non-rotating wobble plate 16 are connected by a rod 22, and as the inclination angle of the drive swash plate 13 changes, the reciprocating stroke of each piston 23 is changed via the non-rotating wobble plate 16. Things are starting to change.

A valve plate 27 is attached between the cylinder block 24 and the head 30.
A compression chamber 26 is formed on the front surface of the piston 23, and a crank chamber 1 is formed on the rear surface of the piston 23.
It communicates with 2. As shown in the figure, this valve plate 27 has a suction port 28a that communicates with a suction port 29 formed in the head 30, and a discharge port 28b that communicates with a discharge port 33 formed in the head 30.
is formed. Furthermore, this valve plate 27 has a suction port 28 during the suction process when the piston 23 moves backward.
A suction valve 34a is installed which opens the suction port 28a during the discharge process and closes the suction port 28a during the discharge process.
A discharge valve 34b opens the discharge port 28b during the discharge process in which the valve moves forward and closes the discharge port 28b during the suction process.
is installed.

The inclination angle of the drive swash plate 13 is changed by changing the pressure difference before and after the piston 23, that is, by changing the pressure inside the crank chamber 12. In order to control this pressure, a pressure control valve 51 is attached to the head 30, and a valve body 52 embedded in the head 30 has a
A suction side pressure chamber 32 is formed which communicates with the suction port 29 via a communication path 31. This valve body 52 has a supply passage 53 formed in the cylinder block 24 and the head 30, and a suction port 29.
A suction-side communication passage 54 is formed that communicates the two via the suction pressure chamber 32 and the communication passage 31. Further, a discharge side communication passage 55 is formed in the valve body 52, which communicates the discharge port 33 with the supply passage 53 via a discharge side pressure chamber 35 formed in the head 30. Note that one supply passage 53 may be formed corresponding to each of the suction side communication passage 54 and the discharge side communication passage 55.

A first electromagnetic valve 57 for opening and closing the suction side communication passage 54 is provided in the cylinder body 56 provided in the valve body 52.
Further, a second electromagnetic valve 58 for opening and closing the discharge side communication passage 55 is provided. These electromagnetic valves 57 and 58 are provided with a resilient force by a coil spring 59 in the direction of closing the communication passages 54 and 55, respectively.

In order to control the opening and closing of the first electromagnetic valve 57, the pressure control valve 51 actually has a
An electromagnetic coil 60 is provided. Further, in order to control opening and closing of the second electromagnetic valve 58, an electromagnetic coil 61 is provided on the valve body 52. These electromagnetic coils 6
0 and 61 are connected to a microcomputer (hereinafter simply referred to as "microcomputer") 62 shown in FIG. 2, which includes a built-in circuit corresponding to the crank chamber pressure control means 72. In addition to the crank chamber pressure control means 72 shown in FIG. 1, the microcomputer 62 includes circuits corresponding to cycle load comparison means 71 and blowout temperature comparison means 75. The microcomputer 62 also includes a pressure sensor 63 that detects the pressure of the refrigerant on the outlet side of the evaporator 7, as shown in FIG.
is connected. This pressure sensor 63 corresponds to the cycle load detection means 70 shown in FIG. 1, and detects the heat load acting on the cooling cycle. Furthermore, the microcomputer 62 includes an evaporator 7
A temperature sensor 64 is connected to detect the temperature of the air blown out. This temperature sensor 64 corresponds to the blowout temperature detection means 73 shown in FIG. Furthermore, the microcomputer 62 is connected to a variable resistor 67 that detects the set position of a temperature control lever 66 provided in a control panel 65 operated by a passenger. This temperature control lever 66
The variable resistor 67 that detects the setting position corresponds to the target outlet temperature detection means 74 shown in FIG. 1, and serves as a reference for determining the target outlet temperature.

Next, the operation of the control device for such a variable capacity swash plate compressor will be explained based on FIG. 3.

At step 80, when the automotive cooling cycle is activated and the control device according to the present embodiment is activated, the microcomputer 6 shown in FIG.
The set position of the lever 66 corresponding to the target blowing temperature Te is read into the microcomputer 62 by the variable resistor 67 connected to the microcomputer 62 (step 81).

Almost simultaneously, in step 82, the actual temperature T of the air blown into the vehicle interior after passing through the evaporator 7 is read into the microcomputer 62 by the temperature sensor 64 shown in FIG.

Next, in step 83, the blowout temperature comparison means 75 shown in FIG.
It is compared whether the temperature difference (T-Te) between the actual blowout temperature T and the target blowout temperature Te is equal to or higher than a predetermined temperature To. When (T-Te)≧To, it is considered that rapid cooling is required, so in this case the process goes to step 86, and if not, the process goes to step 84.

In step 84, the pressure sensor 63 shown in FIG.
The refrigerant pressure on the discharge side of the evaporator 7, that is, the refrigerant pressure on the suction side of the compressor 50 (compressor suction pressure) Ps is read into the microcomputer 62 from . this pressure
Ps has a correlation with the heat load acting on the evaporator 7, that is, the heat load (cycle load) of the cooling cycle, and the cycle load can be determined from this.

Next, in step 85, it is determined whether this compressor suction pressure Ps is greater than a predetermined target suction pressure Pe. This determination is made by cycle load comparison means 71 shown in FIG. 1 built into the microcomputer 62. When the compressor suction pressure Ps is larger than the target suction pressure Pe, it indicates that the cycle load is high. Therefore, in such a case, proceed to steps 86 and 87. In the opposite case, it is determined that the cycle load is low, and in this case, the process goes to steps 89 and 90.

In steps 86 and 87, the crank chamber pressure control means 72 shown in FIG. 1 opens the first solenoid valve 57 and closes the second solenoid valve 58, as shown in FIG. 4A. By opening the first solenoid valve 57 in this manner, a compressor suction pressure Ps lower than the compressor discharge pressure (compressor discharge pressure) Pd is generated in the crank chamber 12 through the suction side communication passage 54 and the supply passage 53. , the pressure difference between the pressure acting on the rear surface of the piston and the pressure acting on the front surface during the suction stroke as shown in FIG. Thus, the inclination angle of the drive swash plate 13, that is, the non-rotating wobble plate 16, with respect to the drive shaft 11 becomes large. As a result, the stroke of the reciprocating piston 23 becomes longer, the compressor discharge capacity for the same number of revolutions increases, and an appropriate flow rate of refrigerant corresponding to the high load flows into the cycle. Note that FIG. 4A shows a state in which the illustrated piston 23 has advanced to the top dead center, and FIG. 4B shows a state in which the illustrated piston 23 has retreated to the bottom dead center.

Next, in step 88, it is determined whether or not to end the control. If it is to be continued, the process returns to step 81; otherwise, the control is ended (step 100). The decision whether to continue with this control is
For example, this is done based on whether the air conditioner switch is on.

In step 85, the compressor suction pressure Ps reaches the predetermined pressure Po.
If it is determined that the cycle load is low, please proceed to step 89.
Go to 90. There, by the action of the crank chamber pressure control means 72 shown in FIG. 1, as shown in FIG. 4C,
The first solenoid valve 57 is closed and the second solenoid valve 58 is opened.
When the second electromagnetic valve 58 opens in this manner, the compressor discharge pressure Pd of the discharge port 33, which is a relatively high pressure, is supplied into the crank chamber 12 via the supply path 53. Then, the piston 23 in the suction process
(The state shown in Fig. 4B) The pressure difference between the front and rear of the piston becomes large, and the non-rotating wobble plate 1
A moment acts in the direction that makes 6 stand up. As a result, the inclination angle of the non-rotating wobble plate 16 becomes almost perpendicular to the drive shaft 11. Therefore, the reciprocating stroke of the piston becomes shorter,
The discharge capacity of the compressor for the same rotational speed is reduced, allowing an appropriate flow rate of refrigerant to flow into the cycle in accordance with the low load.

Next, when steps 89 and 90 are completed, step
Go to 88, and if the control is not finished, repeat the steps described above.

According to such control, it is determined in step 83 whether or not rapid cooling is necessary, and if rapid cooling is necessary, steps 86 and 87 are repeated preferentially to achieve the conditions shown in FIGS. As shown by B, the compressor suction pressure Ps is continued to be introduced into the crank chamber 12, the reciprocating stroke of the piston 23 is maximized, and a large amount of refrigerant is circulated within the cooling cycle. Then, as shown by the solid line a in FIG. 5A, the compressor suction pressure Ps, which is the refrigerant pressure on the discharge side of the evaporator, decreases rapidly, causing a so-called overshoot. Along with this, as shown by the solid line b in Figure B,
The temperature T of the air blown into the vehicle interior through the evaporator also rapidly decreases.

Therefore, rapid cooling becomes possible.

Then, at the point in time to when the temperature difference between this blowing temperature T and the target blowing temperature Te becomes less than To, the control in steps 84 and 85 shown in FIG. 3 is started, and thereafter,
Control is performed to bring the compressor suction pressure Ps closer to the target suction pressure Pe. This allows an appropriate flow rate of refrigerant to flow into the cycle in accordance with the cycle load. The temperature difference To is a value determined through experiments or the like, and is stored in the microcomputer 62 as data. Note that this temperature difference To may be a negative value, and in that case, the blowout temperature T can also be overshot, so that rapid cooling is also possible. However, in this case, it is no longer possible to determine in step 83 whether rapid cooling is necessary or when normal control is sufficient, so a new circuit for this purpose must be provided.

Note that the dotted lines c and d in FIG. 5 show the time changes in the compressor suction pressure Ps and the blowout temperature T by the control device according to the conventional example, and the control by the control device according to the present embodiment is more suitable for rapid cooling. I can see that

Note that the present invention is not limited to the embodiments described above, and can be modified in various ways.

For example, the cycle load detection means 70 is not limited to the pressure sensor 63, but may be a temperature sensor that detects the temperature of the refrigerant on the discharge side of the evaporator 7, or a combination of the pressure sensor and the temperature sensor. The sub-cooling amount detecting means for the refrigerant may be made of: Furthermore, the crank chamber 12
Since the cycle load can be estimated by detecting the internal pressure, the cycle load detection means 70 may be a pressure sensor provided inside the crank chamber. Further, since the cycle load can be estimated by detecting the compression ratio of the compressor, the cycle load detection means 70 may be a compression ratio detection means of the compressor.

Further, the blowout temperature detection means 73 is not limited to the temperature sensor 64 provided immediately after the evaporator 7, but may be, for example, an inside air sensor that detects the temperature inside the vehicle interior. In that case, the vehicle interior temperature is compared with a set value, and the control according to the present invention is performed based on this. Furthermore, the target blowout temperature detection means 74 is not limited to a variable resistor, and may be, for example, data stored in the microcomputer 62 in advance.

[Effects of the invention] As explained above, according to the invention, in a variable capacity swash plate compressor, the case where rapid cooling is required is automatically detected, and in this case, the discharge of the compressor is prioritized. By maximizing the amount, the cool-down characteristics of the cooling cycle are greatly improved. Furthermore, according to the present invention, when rapid cooling is not required, the refrigerant flow rate is controlled according to the heat load of the cooling cycle, which improves the fuel efficiency of the engine that drives the compressor and saves energy. It has the excellent effect of being able to achieve the following.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing the configuration of the present invention;
The figure is a schematic configuration diagram of a variable capacity swash plate compressor and its control device according to an embodiment of the present invention, and FIG. 3 is a flowchart showing the operation of the embodiment.
4A to 4C are schematic sectional views of a variable capacity swash plate compressor according to the same embodiment, FIGS. 5A and 5B are graphs showing control characteristics according to the same embodiment, and FIG. 6 is a cooling cycle for an automobile. It is a schematic diagram. 11... Drive shaft, 12... Crank chamber, 13...
... Drive swash plate, 16 ... Wobble plate, 23 ... Piston, 26 ... Compression chamber, 28a ... Suction port,
28b...Discharge port, 54...Suction side communication path,
55...Discharge side communication path, 57...First solenoid valve, 5
8...Second solenoid valve, 62...Microcomputer, 63...
Pressure sensor, 64... Temperature sensor, 67... Variable resistance, 70... Cycle load detection means, 71...
Cycle load comparison means, 72...Crank chamber pressure control means, 73...Blowout temperature means, 74...Target blowout temperature detection means, 75...Blowout temperature comparison means.

Claims (1)

[Claims for Utility Model Registration] A plurality of pistons 23 mounted in a cylinder block 24 so as to be able to reciprocate in the axial direction are connected to the drive shaft 11.
The pressure in the compression chamber 26 formed in front of the piston 23 and the pressure in the compression chamber 26 formed in the rear of the piston 23 are controlled so that the pressure in the compression chamber 26 formed in the front of the piston 23 and the pressure in the compression chamber 26 formed in the rear of the piston 23 are In the variable capacity swash plate type compressor, the stroke of the piston 23 is changed by changing the inclination angle of the drive swash plate 13 according to a change in the differential pressure between the drive swash plate 13 and the pressure in the crank chamber 12. cycle load detection means 63, 70 for detecting the heat load of the cooling cycle in which the cooling cycle is installed; cycle load comparison means 71 for comparing whether the cycle load detected by the cycle load detection means is equal to or higher than a predetermined value; and the cooling cycle. Blowout temperature detection means 6 for detecting the temperature of the actual air cooled and blown out.
4, 73, and target blowout temperature detection means 67 for detecting the target blowout temperature of the air cooled by the cooling cycle.
74, a blowout temperature comparison means 75 for comparing the temperature difference between the temperature detected by the blowout temperature detection means 64, 73 and the target temperature detected by the target blowout temperature detection means 67, 74; and the blowout temperature comparison means 75. and crank chamber pressure control means 51 and 72 that change the pressure in the crank chamber 12 according to the output signal from the cycle load comparison means 71, and the temperature difference compared by the blowout temperature comparison means 75 is a predetermined temperature. In the above case, the variable capacity swash plate type compressor is characterized in that the pressure in the crank chamber 12 is controlled by the crank chamber pressure control means 72 preferentially based on the output signal from the outlet temperature comparison means. Control device.