JPH10159749A - Compressor control device for vehicular air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrict the operation of an air conditioner only when a compressor requires consideration about the protection thereof, and improve the comfortability of an air conditioner operation by making judgement about whether a compressor operation state is within the range of a compressor operation zone, and reducing a load on the compressor when the judgement is negative. SOLUTION: The control part of a compressor 10 has an engine speed sensor 23 to detect the number of revolutions of an engine 1 per unit time, a delivery pressure sensor 21 to detect compressor delivery pressure, and a microcomputer 20 to receive and then process output data from the sensors 23 and 21. Regarding the microcomputer 20, an engine speed and compressor delivery pressure are collated with compressor operation zone data stored in a memory, thereby making judgement whether the operation state of the compressor 10 is within the range of the compressor operation zone data. When the operation state is identified as outside the range, the delivery capacity of the compressor 10 is controlled for reducing a load thereon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for controlling a compressor of an air conditioner, and more particularly to a compressor of an air conditioner for a vehicle for controlling a compressor of an air conditioner for a vehicle.

[0002]

2. Description of the Related Art At present, most air conditioners mounted on automobiles use a compressor having a structure linked to rotation of an engine. In such a compressor, a compressor body and a clutch pulley are provided with a clutch interposed therebetween, a belt for transmitting the rotation of the engine is hung on the clutch pulley, and the clutch pulley is rotated in conjunction with the rotation of the engine. . The rotation of the clutch pulley
It is transmitted to the compressor body via the clutch, and rotates the compressor so as to link with the engine. Therefore, the clutch can connect or disconnect the compressor body and the clutch pulley as needed (also referred to as clutch on / off, respectively).
Even when the engine is running at a high speed, the load on the compressor is reduced, and the clutch pulley and the compressor body are separated from each other with priority given to protecting the compressor over air conditioning.

In general, such protection of the compressor is automatically performed by the control unit of the air conditioner. For example, the control unit inputs the number of revolutions of the engine to the control unit and performs processing to protect the compressor in advance. The data of the number of revolutions of the power engine should be stored, and when the number of revolutions of the engine reaches the stored number of revolutions, the clutch is turned off to disconnect the clutch pulley from the compressor body. The data of the engine speed is, for example, data as shown in FIG. In the data shown, the horizontal axis indicates the engine speed, and the vertical axis indicates the pressure at which the compressor compresses the refrigerant. The rotational speed N of the engine in the figure is a value stored for disconnecting the compressor body from the clutch pulley, and the regulation value Pb is a compressor that is regulated on the durability of the compressor irrespective of the engine speed. Discharge pressure.

In the conventional control of a compressor, the clutch-off is determined only by, for example, the number of rotations of the engine per unit time, that is, the rotation speed, regardless of the discharge pressure of the compressor. Therefore, for example, the engine rotation speed N1 and the discharge pressure P1 shown in the figure are the engine rotation speed N1 at which the measured engine rotation speed becomes a condition for clutch off even if the discharge pressure of the compressor is equal to or lower than Pb.
Therefore, in this case, the control unit turns off the clutch and stops the operation of the air-conditioning apparatus.

[0005]

However, damage to the compressor by the load related to the high-speed rotation of the engine is limited only when the discharge pressure of the compressor is relatively high at 28 kg / cm ² G or more. Therefore, as described above, if it is determined that the compressor is stopped only based on the engine speed and the clutch is turned on and off, the compressor discharge pressure is low, and the compressor may be damaged even if the engine is rotating at high speed. If low, the compressor could be turned off. In such a case, the operation of the air conditioner is stopped even though the protection of the compressor is unnecessary, and the air conditioning function cannot be performed.

The present invention has been made in view of the above points, and restricts the operation of an air conditioner only when protection of a compressor is to be considered, thereby achieving both compressor protection and air conditioning functions. It is an object of the present invention to provide a compressor control device of an air conditioner for a vehicle that can perform the control.

[0007]

According to a first aspect of the present invention, there is provided a compressor control device for a vehicle air conditioner, which controls a compressor that operates in conjunction with an engine of the vehicle air conditioner. A compressor data storage means for storing compressor operating area data limited by an engine speed and a compressor discharge pressure corresponding to the engine speed; an engine detection means for detecting an engine speed of an automobile; and a compressor discharge pressure. The compressor operating area data stored in the compressor data storage means and an engine speed detected by the engine detection means and a compressor discharge pressure detected by the discharge pressure detection means are compared with each other. Operating state is the compressor operating area The compressor operation determining means for determining whether or not the compressor is in the range, and the compressor operation determining means, when it is determined that the operating state of the compressor is not within the range of the compressor operating region, the load on the compressor. And compressor protection means for reducing.

With this configuration, the operating state of the compressor is determined in consideration of both the discharge pressure of the compressor and the number of revolutions of the engine, and if necessary, the load on the compressor can be reduced. become.

According to a second aspect of the present invention, there is provided a compressor control device for an automobile air conditioner, wherein the compressor has a structure capable of controlling a discharge pressure by changing a discharge capacity by an external electric signal. The means reduces the load on the compressor by reducing the discharge pressure of the compressor.

With this configuration, it is possible to reduce the discharge pressure of the compressor within a range of the discharge pressure at which the compressor is not damaged according to the engine speed, thereby protecting the compressor.

According to a third aspect of the present invention, there is provided a compressor control device for an air conditioner for an automobile, wherein the compressor protection means reduces a load on the compressor by preventing rotation of an engine from being transmitted to the compressor. Things.

With this configuration, it is possible to prevent the compressor from interlocking with the engine and protect the compressor.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment FIG. 1 is a diagram showing a configuration of a compressor control device of an air conditioner for a vehicle according to the present embodiment. The illustrated configuration mainly includes a refrigerant circulation cycle for performing air conditioning and a control unit for protecting the compressor 10 included in the refrigerant circulation cycle. The refrigerant circulation cycle includes an externally controlled variable capacity compressor 10, a condenser 2, an evaporator 4, a liquid tank 8, and an expansion valve 6, which are connected by a pipe through which the refrigerant flows. Compressor 10
Is connected or disconnected arbitrarily by a clutch pulley 11 and a clutch 13 for transmitting the rotation of the engine, and is configured to switch between rotation and stop.

The compressor rotates by being connected to the engine, inhales, compresses and discharges the refrigerant, sends out the refrigerant in a high-temperature and high-pressure gas state into the pipeline, and the sent refrigerant is connected to the outside air by the condenser 2. It is condensed by releasing heat by performing heat exchange, and is sent to the liquid tank 8 in a gas-liquid mixed state. In the liquid tank, the refrigerant is separated into gas and liquid, and only the liquid refrigerant is sent to the expansion valve 6,
In the expansion valve 6, the liquid refrigerant is further decompressed and atomized, and is sent to the evaporator 4 in a state where it is easily evaporated. The low-temperature liquid refrigerant that has flowed into the evaporator 4 evaporates while exchanging heat with air in contact with the outer surface of the evaporator 4, deprives the air of latent heat of evaporation, goes to the outlet, and is sucked into the compressor 10 again.

The control unit of the compressor 10 includes the engine 1
Engine speed sensor 23 for detecting the number of revolutions per unit time, discharge pressure sensor 21 for detecting the discharge pressure of the compressor, and microcomputer 20 for inputting and processing them.
And The transmission and reception of electrical signals performed here will be described with reference to FIG. The microcomputer 20 is shared with a configuration for controlling the air conditioning process in the air conditioner.
Sensors 32, 3 for detecting air conditioning setting conditions set by the occupant on the control panel 31, the amount of solar radiation given to the passenger compartment, the temperature of the air outside the passenger compartment, and the temperature of the air in the passenger compartment.
3. Further, a measurement value of a sensor 34 for detecting the air blowing temperature immediately after the evaporator 4 is also input. Further, as a configuration for protecting the compressor of the microcomputer 20, the microcomputer 5 has a memory 5 for storing determination data defining an operating range in which the compressor is allowed to operate based on measured values of the discharge pressure sensor 21 and the engine speed sensor 23.

FIG. 3 shows an example of the determination data stored in the memory 5. In the data of FIG. 3, the vertical axis indicates the discharge pressure of the compressor, and the horizontal axis indicates the rotation speed of the engine. The limit value Pa in the figure is a discharge pressure at which continuous operation can be performed without damaging the compressor, and the regulation value Pb is an upper limit value of the discharge pressure at which the compressor is normally operated, and a margin value Pc.
Is the difference between the limit value Pa and the regulation value Pb, and the line segment m is a line segment representing the discharge pressure at which the compressor is allowed to operate, and is a linear function of the engine speed. Also, the upper limit value of the rotation speed of the engine shown in FIG. The measurement points (N1, P1) shown in the graph are the same as the measurement points shown in FIG. 8, and the engine rotation speed N1 at the measurement point (N1, P1) is not less than N, and P1 is not more than the regulation value Pb. It is equal to or less than the value Pa. In such a case, in the present embodiment, processing is performed so that the discharge pressure of the compressor is controlled so that the measured value P1 becomes equal to or less than the regulation value Pb, and the rotation of the compressor is continued. Therefore, in addition to the range of the compressor operation shown in FIG. 8, the compressor operation in the shaded region shown in FIG. 3 is allowed.

Since the compressor 10 of the present embodiment is an externally controlled variable displacement compressor as described above, the discharge pressure of the compressor 10 is constantly controlled by an electric signal input from the microcomputer 20.

Here, the compressor 10 of the present embodiment
Will be described with reference to FIGS. 9 and 10. FIG.

The compressor 10 is a swash plate type external control type variable displacement compressor having a drive shaft 57 which is driven to rotate by an engine via a belt, a pulley 11 and a clutch 13. The swash plate 55 is connected to the drive shaft 57 so that the swash plate 55 can tilt and swing, and the rotational force of the drive shaft 57 is transmitted to the swash plate 55. A non-rotating socket plate 58 is slidably attached to the swash plate 55, so that the rotation of the swash plate 55 causes a so-called razor-like operation to reciprocate in the axial direction. This reciprocating motion causes the piston rod 59 to reciprocate the piston 53, and the entire surface side of the piston 53 of the cylinder 52 in which the piston 53 is inserted becomes a compression chamber and is connected to the rear side crank chamber 54. The five pistons 53 and the cylinders 52 are arranged at equal intervals in the circumferential direction, and the resultant acts on the inclination of the swash plate 55. The suction port 56 is a portion where the return refrigerant from the evaporator flows into the suction chamber 60, and the discharge port 51 is a portion where the compressed refrigerant flows out.

The inclination of the swash plate 55 is determined by the difference between the pressure in the crank chamber 54 and the pressure in the cylinder 52. The larger the inclination of the swash plate 55, the longer the stroke (stroke) of the cylinder 52 reciprocating in the piston 53. And the smaller the inclination, the shorter the stroke of the cylinder 52 (de-stroke). By performing the stroke, the capacity of the refrigerant discharged from the cylinder 52 is reduced, and the discharge pressure of the compressor 10 is also reduced.

Such a crank chamber 54 and a cylinder 52
Is controlled by a control valve 80. A more detailed configuration of the control valve 80 will be described with reference to FIG. The control valve 80 is
A plunger 86, a coil 83 wound around the plunger 86, an upper spring 81 provided below the plunger 86, and a valve 85 provided above the plunger 84; The lower refrigerant passage 84 connects the crank chamber 54 and the suction chamber 60, and
The refrigerant slightly flows from the suction chamber 4 to the suction chamber 60.

The control valve 80 is connected to the microcomputer 20
Input the electrical signal output from the point indicated by A,
The pressure in the crank chamber 54 is controlled by opening and closing the valve by this signal and changing the discharge capacity of the refrigerant.

When no electrical signal is input to the control valve 80, the valve 85 is open as shown in FIG. Since the crank chamber 54 and the suction chamber 60 are always in communication with each other through the refrigerant passage 84, when the valve 85 is in an open state, the refrigerant flows out of the crank chamber 54 into the suction chamber 60 and the discharge port 5
1 flows into the crank chamber 54. The amount of refrigerant flowing from the discharge port 51 into the crank chamber 54 is larger than the amount of refrigerant flowing into the suction chamber 60 via the refrigerant passage 84, and the valve 85
, The pressure in the crank chamber 54 rises, becomes larger than the pressure on the suction side, and the combined force of the forces applied to the back surfaces of the plurality of pistons 53 acts on the socket plate 59,
It acts to reduce the angle of inclination of the socket plate 59.

When the inclination angle of the socket plate 59 decreases, the plurality of pistons 53 cannot retreat by a sufficient stroke, and can perform only a slight compression stroke when entering the next compression step, so that the amount of compressed refrigerant is reduced. Less,
The discharged refrigerant amount is also small, the flow rate of the refrigerant circulating in the cooling cycle is reduced, and the pressure of the refrigerant discharged from the compressor 10 is also reduced.

On the other hand, when an electric signal is supplied to the control valve 80, a current flows through the coil 83, and a magnetic field is generated around the current flowing through the coil 83. This magnetic field generates a force to pull down the plunger 86 in order to equalize the intensity distribution, and the plunger 86 is pulled down by the force generated in the coil as shown in FIG. Open 85. Since the crank chamber 54 and the suction chamber 60 are always in communication with each other through the refrigerant passage 84, in the crank chamber 54, the refrigerant flows out to the suction chamber 60 without being supplied from the discharge port 51, and the pressure decreases. .

Therefore, the pressure difference between the front and rear of the piston 53 in the suction process becomes small, and the piston 53 can be smoothly retracted in the cylinder 52.
5 and the socket plate 59 are inclined at the maximum inclination angle with respect to the drive shaft 57, and the stroke of the reciprocating motion of the piston 53 is increased. When compression is performed in this state, the amount of refrigerant discharged increases, the amount of refrigerant circulating in the cooling cycle also increases, and the pressure of refrigerant discharged from the compressor 10 also increases.

In the compressor 10 according to the present embodiment, which is an externally controlled variable displacement compressor, current is intermittently supplied to the coil 83, and the pressure in the crank chamber 54 is increased or decreased depending on the supply time. The discharge pressure of the compressor 10 is always adjusted to a desired value. The desired value is obtained from the measurement conditions of sensors that detect the air conditioning setting conditions set by the occupant by the microcomputer 20, the amount of insolation given to the cabin, the temperature of the air outside the cabin, and the temperature of the air in the cabin. Further, it is calculated from a measurement value of a sensor that detects the air blowing temperature immediately after the evaporator 4.
In this embodiment, in order to protect the compressor, the microcomputer 20 further inquires the measured values of the discharge pressure sensor 21 and the engine rotational speed sensor 23 into the judgment data stored in the memory 5, and as a result of the inquiry, this value is If the discharge pressure and the engine speed exceed the allowable ranges defined by the determination data, the microcomputer 20 increases the time for supplying current to the coil 83 by the electric signal sent to the control valve 80, and Decrease pressure.

The electric signal sent from the microcomputer 20 to the control valve 80 is generally a rectangular pulse signal as shown in FIG.
And the current is supplied to the coil 83 only while the voltage is turned off, thereby lowering the discharge pressure of the compressor 10. The duty ratio refers to the ratio of the ON time in the cycle obtained by adding the ON time and the OFF time of the voltage. In the present embodiment, when the measured value P1 is out of the range of the regulation value Pb, the duty ratio is reduced so as to fall within the range, the pressure in the crank chamber 54 is increased, and the swash plate 13 is destroke. In this case, the discharge pressure of the compressor is lowered to keep the measured value P1 within the range of the regulation value Pb.

Next, the processing performed in the above-described first embodiment will be described with reference to a flowchart of FIG.

The process of the present embodiment starts when the air conditioner is turned on (S1). After the air conditioner is turned on, the engine speed N1 measured by the engine speed sensor is compared with a conventional engine upper limit value N (S2), and N
If 1 is greater than or equal to N, the measured value P of the discharge pressure sensor
1 is compared with the formula of αN1 + β (S3). This equation is obtained by substituting the measured value of the current engine speed N1 into the linear function of the speed representing the line segment m shown in FIG. 3, and the discharge pressure allowable when the engine speed is N1. The upper limit is calculated. Therefore, the measured discharge pressure P1 is α
If it is larger than N1 + β, P1 is set to αN1 + β by adjusting the duty ratio of the voltage waveform as described above.
(S4). This adjustment of the duty ratio is continued until the engine rotation speed N1 becomes equal to or less than N or P1 becomes equal to or less than the upper limit value.

If P1 is smaller than αN1 + β in step 3, the ON / OFF duty ratio of the electric signal for controlling the compressor is set as usual (S
6). If N1 is less than N in step 2, P1 is further compared with Pb (S5).
If the pressure is equal to or lower than Pb, the control shifts to the normal control of the compressor (S6). If P1 exceeds Pb, the discharge pressure of the compressor is controlled so that P1 falls within the range of Pb (S7).

In the above-described embodiment, the compressor is protected in consideration of not only the rotational speed of the engine but also the discharge pressure of the compressor.
Even when the engine is rotating at high speed, it is possible to operate the compressor by reducing the discharge pressure of the compressor according to this rotation speed, preventing the air conditioning operation from stopping more than necessary. . Therefore, even when the engine is rotated at a high speed, the compressor can be operated.

In this embodiment, an example is described in which a swash plate type external control type variable displacement compressor is used as the external control type compressor. However, the present invention is not limited to such a configuration. An external control type variable displacement compressor may be used.

Further, since the regulation value Pb is set with a margin of Pc with respect to the limit value Pa of the compressor, the reliability of compressor protection can be improved.

Second Embodiment FIG. 6 is a diagram showing a configuration of a compressor control device of an air conditioner for a vehicle according to the present embodiment. The illustrated configuration includes a refrigerant circulation cycle and a control unit for protecting the compressor 15 included in the cooling circulation cycle. Since the configuration of the present embodiment is substantially the same as the configuration described in the first embodiment, a detailed description of each unit will be omitted,
Only the configuration specific to the present embodiment will be described below.

The compressor 15 used in the refrigerant circulation cycle of the present embodiment has a fixed capacity, and the microcomputer 20 of the control unit includes an engine speed sensor 23 and a discharge pressure for detecting the discharge pressure of the compressor. The respective detection values are input from the sensor 21, and the connection between the clutch 13 and the compressor 15 is turned on and off based on these values. The microcomputer 20 of the present embodiment also incorporates the judgment data described with reference to FIG.
It is determined whether or not 1) is within the compressor operating range of the determination data. If not, control is performed so that the clutch 13 is turned off to temporarily suspend the compressor operation and keep the compressor within the operating range. doing.

Next, the processing performed in the above-described second embodiment will be described with reference to a flowchart of FIG.

The processing of this embodiment starts when the air conditioner is turned on (S11). After the air conditioner is turned on, the engine speed N1 measured by the engine speed sensor is compared with the conventional engine upper limit value N (S12).
If N1 is equal to or larger than N, the measured value P1 of the discharge pressure sensor is compared with the formula of αN1 + β (S13). This equation is obtained by substituting the measured value of the current engine speed N1 for the engine speed of the linear function representing the line segment m shown in FIG. 3, and the discharge permitted when the engine speed is N1. The upper limit of the pressure is determined. Therefore, if the measured discharge pressure P1 is larger than αN1 + β, the clutch is turned off and the compressor is temporarily stopped (S14).
1 is within the range of αN1 + β. When the clutch is turned off, the engine speed becomes N or less, or P1 becomes α
It continues until it becomes equal to or less than N1 + β, and if the determination in step 12 is NO, P1 is further compared with Pb (S15).
As a result, if P1 is equal to or less than Pb, the control shifts to the normal control of the compressor (S16). If P1 exceeds Pb, the clutch is turned off.

In the present embodiment described above, the effects obtained in the first embodiment can be obtained without using an externally controlled compressor having a variable capacity.

[0040]

According to the first aspect of the present invention, there is provided a compressor control device for an air conditioner for a vehicle, wherein the compressor data stores compressor operating region data limited by an engine speed of the vehicle and a discharge pressure of the compressor according to the engine speed. The operating state of the compressor can be determined by comparing the discharge pressure of the compressor with the engine speed in the storage means. Therefore, the allowable engine speed is changed according to the compressor discharge pressure, and the compressor can be operated in a wider range of the engine speed, thereby achieving both air conditioning and compressor protection.

The compressor control device for an air conditioner for a vehicle according to the second aspect can maintain the operation of the compressor while adjusting the discharge pressure so that the discharge pressure of the compressor corresponds to the engine speed. Therefore, it is possible to operate the compressor in a wider range of engine speed, and it is possible to achieve both air conditioning and compressor protection.

If the discharge pressure of the compressor exceeds the limit value even when the engine speed is low, the compressor is operated without stopping by adjusting this value to be within the compressor operating range. You can continue.

Also, since the discharge pressure of the compressor is lowered by lowering the discharge capacity of the compressor,
The torque applied to the compressor is also reduced, which can also reduce the load on the engine.

According to a third aspect of the present invention, there is provided a compressor control device for an air conditioner for an automobile, wherein the operation of the compressor is controlled while adjusting the operation of the compressor by turning on and off the clutch so that the discharge pressure of the compressor corresponds to the engine speed. Can be maintained. Therefore, it is possible to operate the compressor in a wider range of engine speed, and it is possible to achieve both air conditioning and compressor protection.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a diagram showing transmission and reception of signals performed by a control unit according to the first embodiment of the present invention.

FIG. 3 is a diagram showing common determination data in the embodiment of the present invention.

FIG. 4 is a diagram illustrating a compressor control signal output from a control unit according to the first embodiment of the present invention.

FIG. 5 is a flowchart illustrating a process performed in the first embodiment of the present invention.

FIG. 6 is a diagram showing a configuration of a second exemplary embodiment of the present invention.

FIG. 7 is a flowchart illustrating processing performed in a second embodiment of the present invention.

FIG. 8 is a diagram showing conventional determination data.

FIG. 9 is a diagram illustrating a configuration of a compressor used in the first embodiment of the present invention.

10 is a diagram illustrating a configuration of a control valve of the compressor in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine, 10 ... External control type variable displacement compressor, 11 ... Clutch pulley, 13 ... Clutch, 15 ...
Fixed displacement compressor, 20: microcomputer, 21: discharge displacement sensor, 23: engine rotation speed sensor.

Claims (3)

[Claims] 1. A control device for controlling a compressor (10, 15) of an air conditioner for a vehicle which operates in conjunction with an engine (1), the control device comprising: Compressor data storage means (5) for storing compressor operating area data limited by the discharge pressure; engine detection means (23) for detecting the number of revolutions of the engine of the vehicle; discharge pressure detection means for detecting the discharge pressure of the compressor (21) and the engine detection means (2) in the compressor operating area data stored in the compressor data storage means (5).
The engine speed detected by 3) is compared with the compressor discharge pressure detected by the discharge pressure detecting means (21), and whether or not the operating state of the compressor (10, 15) is within the range of the compressor operating area data. When the compressor operation determining means (20) determines that the operating state of the compressor (10, 15) is not within the range of the compressor operating area data,
A compressor control device for an air conditioner for a vehicle, comprising: compressor protection means (20) for reducing a load on the compressor (10, 15). 2. The compressor (10) has a configuration capable of controlling a discharge pressure by changing a discharge capacity by an external electric signal, and the compressor protection means (20) is configured to control a discharge pressure of the compressor. The compressor control device according to claim 1, wherein the load applied to the compressor (10) is reduced by reducing the load. 3. The compressor protection means (20) reduces the load on the compressor (15) by preventing rotation of the engine (1) from being transmitted to the compressor (15). 2. The compressor control device for an automotive air conditioner according to claim 1.