JP2568192B2 - External controller for variable capacity compressor - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for externally controlling a variable displacement compressor called an internal displacement variable type in an air conditioner installed in a vehicle.

(Prior Art) Conventionally, as an air conditioner for an automobile of this type, a compressor (compressor) drivingly connected to an in-vehicle engine through an electromagnetic clutch mechanism, and a gas refrigerant discharged from the compressor are used as heat from air. It is equipped with a condenser (condenser) that cools and condenses into a liquid state by replacement, and an evaporator (evaporator) that vaporizes the liquid refrigerant that has passed through this condenser and cools the passenger compartment by the heat of vaporization. It is generally well known that the frost switch detects that the evaporation temperature of the refrigerant falls below a predetermined temperature and stops the operation of the compressor by turning off the electromagnetic clutch mechanism. Has been done.

That is, when the engine speed increases, the amount of refrigerant discharged from the compressor driven by the engine increases, and a large amount of refrigerant circulates in the refrigerant circuit. Since the load is substantially constant, the capacity becomes surplus, and the drive of the compressor is stopped to eliminate this surplus portion.

However, in that case, in order to reduce the driving force for driving the compressor of the engine and improve the EER (energy consumption efficiency), rather than stopping the operation of the compressor once and then restarting it, in the meantime, It is preferable to continue the operation by reducing the capacity of the above compared to the steady state. For example, among the compressors, condensers, and evaporators, looking at the dependence of these devices on the coefficient of performance, the smaller the capacity of the compressor, the lower the work capacity of the compressor itself, but the contribution rate of the condenser and evaporator is relatively large. It becomes large and the overall coefficient of performance increases. In other words, while the work capacity of the compressor is decreasing, the overall enthalpy is the same, so the EER increases.

Therefore, as a compressor that meets such requirements,
Hitherto, as disclosed in Japanese Patent Application Laid-Open No. Sho 60-261721, a compressor with a variable internal capacity has been proposed. this is,
When the compressor capacity becomes excessive, a part of the refrigerant sucked into the compressor body is bypassed from the middle of the compression stroke and returned to the suction side, so that the capacity of the compressor can handle the heat load in the vehicle compartment Is controlled automatically.

(Problems to be solved by the invention) However, on the other hand, when using the proposed variable internal capacity compressor, the capacity of the compressor is automatically controlled to the capacity corresponding to the heat load in the vehicle interior. The following problems arise.

That is, for example, when the vehicle is in the idling state for a short time such as waiting for a signal and the traveling is stopped, if the heat load in the passenger compartment at that time is large,
The compressor has a problem that its capacity is automatically controlled to a large extent, the proportion of the engine output consumed for driving the compressor increases, and as a result, the engine load increases and its idling vibration increases. .

The present invention has been made in view of the above problems, and an object thereof is, in addition to the original automatic internal capacity control in the variable content capacity type compressor as described above, the capacity to be adjusted from the outside depending on the external conditions. By properly controlling the internal capacity, the load on the engine for driving the compressor when the vehicle is stopped for a short time is reduced as much as possible while taking advantage of the characteristics of the variable internal capacity compressor. This is to reduce the idling vibration of the engine.

(Means for Solving the Problem) In order to achieve this object, the solution means of the present invention temporarily controls the internal capacity of an air conditioner compressor when it is considered that the vehicle is stopped for a short time. This is prohibited and the capacity is fixedly held at the minimum capacity.

Specifically, the configuration of the present invention is as shown in FIG.
A suction port 21 for sucking the refrigerant, and a discharge port 22 for discharging the refrigerant that has been sucked from the suction port 21 and passed through the compression stroke
And a variable capacity mechanism 50 that variably controls the discharge amount of the refrigerant according to the suction pressure of the refrigerant, the engine mounted on the vehicle.
It is premised on an external control device for externally controlling the variable capacity compressor 2 for an air conditioner driven by 12.

The compressor 2 is provided with a capacity setting mechanism 52 for keeping the discharge amount of the refrigerant to a minimum.

Further, it is detected that the vehicle can be considered to have stopped traveling for a short time, that is, the throttle opening of the engine 12 and the vehicle speed are below a predetermined value and the transmission is in the forward gear position. Vehicle stop detection means
In addition to providing 107, when the output of the vehicle stop detection means 107 is detected and the vehicle stop detection means 107 detects a state in which the vehicle can be considered to stop traveling for a short time, the capacity setting mechanism 52 of the compressor 2 is operated. A control means 108 is provided for controlling.

(Operation) With this configuration, in the present invention, the control means 108 does not operate while the vehicle is traveling, and the internal capacity control of the compressor 2 is performed. On the other hand, a state in which it can be considered that the vehicle has stopped traveling for a short time, that is, a state in which the throttle opening and the vehicle speed of the engine 12 are each less than or equal to a predetermined value and the transmission is in the forward gear position is detected by the vehicle stop detection means 107. Then, the vehicle waits for a signal, etc.
It is considered that the vehicle is temporarily stopped for a short time with 12 being in an idling state, and the control means 108 receiving the output of the vehicle stop detection means 107 prohibits the internal capacity control of the compressor 2 and the capacity setting mechanism. The actuation of 52 forces its capacity to be held fixed at the minimum capacity. This compressor 2
Since the minimum capacity of the engine is fixedly held, the load of the engine 12 required to drive the compressor 2 becomes extremely small,
By reducing the load on the compressor 2, the idling vibration of the engine 12 can be effectively reduced.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings starting from FIG.

FIG. 2 shows the overall configuration of an embodiment of the present invention, and 1 is an air conditioner installed in a vehicle equipped with an electronic fuel injection engine 12 and an electronically controlled transmission (not shown). The device 1 is disposed at the front end of the engine room of the vehicle body and the compressor 2 (compressor) drivingly connected to the vehicle-mounted engine 12 via the electromagnetic clutch mechanism 13 and the transmission belt 14, and by heat exchange with traveling wind or the like. A condenser 3 (condenser) that cools the gas refrigerant and condenses it into a liquid refrigerant, and a receiver tank 4 (liquid receiver) that stores the liquid refrigerant.
And an expansion valve 5 (expansion valve) whose opening degree is adjustable to decompress the liquid refrigerant to a pressure suitable for its vaporization and to expand it.
And an evaporator 6 (evaporator) which is arranged in the vehicle compartment and which vaporizes the liquid refrigerant and cools the air in the vehicle compartment by the heat of vaporization of the liquid refrigerant.
Refrigerant circuit 8 is configured by connecting with each other. Reference numeral 9 is a temperature-sensitive tube attached to the refrigerant pipe 7 that returns from the evaporator 6 to the compressor 2. The temperature-sensitive tube 9 is connected to the expansion valve 5 via a heat transfer tube 10 and vaporized by the evaporator 6. The opening of the expansion valve 5 is automatically adjusted so that the temperature of the gas refrigerant is constant. Reference numeral 11 denotes a fan attached to the evaporator 6.

The compressor 2 is a vane type variable displacement compressor. The basic structure of the variable displacement compressor 2 is similar to that of a normal vane compressor. That is, the main body 20 of the compressor 2 is joined to the ring-shaped side housing 23 and the front and rear surfaces of the side housing 23 in an airtight manner as shown in FIG. Front and rear housings 25 and 26 that form a columnar working chamber 24, and a cylindrical rotor that is rotatably fitted in the working chamber 24 of the side housing 23 so as to be offset with respect to the center of the working chamber 24.
27, and a pair of through vanes 28, 28 that are supported by the rotor 27 so as to be retractable from the outer peripheral portion of the rotor 27 and that partition the working chamber 24 by sliding contact with the inner peripheral wall of the working chamber 24. The housing 25 is formed with a suction port 21 for sucking the refrigerant into the working chamber 24, and a suction chamber 29 communicating with the suction port 21. The side housing 23 has a discharge port 22 for discharging the refrigerant that has undergone the compression stroke, and the rear housing 26 has a discharge chamber (not shown) communicating with the discharge port 22. Furthermore, the rotor
The rotating shaft 31 of 27 is connected to the electromagnetic clutch mechanism 13, and when the electromagnetic clutch mechanism 13 is turned on, the rotor 27 is rotationally driven by the output of the engine 12, and as the rotor 27 rotates, the inside of the side housing 23 is rotated. Vane 2 in working chamber 24 of
By gradually decreasing the volume of the part partitioned by 8 and 28, the gas refrigerant sucked from the suction port 21 of the side housing 23 is compressed and discharged from the discharge port 22.

In this basic configuration, a spool valve 32 is provided in the front housing 25 of the compressor body 20. A pressure regulator 40, which is a needle valve, is attached to the lower portion of both the side housing 23 and the rear housing 26.

As shown in FIG. 4, the spool valve 32 is a cylindrical valve housing 33, and is slidably fitted in the valve housing 33 so that the housing 33 has a spring chamber 35 and a pressurizing chamber 36. The pressurizing chamber 36 includes a port 33a of the valve housing 33 and the port 3a.
It is communicated with a predetermined gap portion between the front housing 25 and the side housing 23 in the compressor body 20 through a communication passage 37 connected to 3a, and the pressure inside thereof is the suction pressure and the discharge pressure of the gas refrigerant. The pressure is set to approximately the middle of. Further, the valve element 34 is placed in the spring chamber 35 as a pressurizing chamber.
A spring 38 for urging toward the 36 side is compressed, and the spring chamber 35 is communicated with the suction chamber 29 in the front housing 25 through the port 33b. further,
In the valve housing 33, four bypass holes 39a to 39b are provided in the middle of the sliding range of the valve body 34 inside, and the bypass holes 39a and 39b among them are opposed to each other in the diametrical direction of the housing 33 and the bypass holes 39a, 39b. Housing 39a to each other (39b, 39b)
The openings are arranged in series in the direction of the center line of 33.
The bypass holes 39a, 39a located on one side (right side in FIG. 3) of the housing 33 are provided on the other side (on the left side) of the working chamber 24 at a portion corresponding to the middle of the compression stroke of the refrigerant.
b and 39b are respectively communicated with the suction chamber 29, and bypass holes 39a and 39b facing each other in the diametrical direction of the housing 33 are provided.
And the spring chamber 35 located between the bypass holes 39a and 39b.
The bypass passages 39, 39 for bypassing the refrigerant to the suction chamber 29 (suction side) in the middle of the compression process of the refrigerant compressed in the working chamber 24 are formed by a part of the refrigerant. And
The urging force of the intermediate pressure in the pressurizing chamber 36 against the valve body 34 is applied to the refrigerant suction pressure in the spring chamber 35 by the spring inside the spring.
When it is larger than the biasing force obtained by adding the spring force of 38,
By moving 34 downward in FIG.
39a to 39b are closed to close the bypass passages 39 and 39,
Conversely, when it is small, the valve body 34 is moved upward in the figure to open the bypass holes 39a-39b and open the bypass passages 39,39.

On the other hand, the pressure regulator 40 includes a valve housing 44 in which first and second two pressure chambers 42, 43 communicating with each other via a valve opening 41 are formed, and the valve opening 41 in the valve housing 44. And a valve body 45 that is fitted so that it can be opened and closed,
The diaphragm 46 is fitted in the second pressure chamber 43 of the valve housing 44 and divides the second pressure chamber 43 into a suction pressure chamber 43a and an atmospheric pressure chamber 43b.
Is connected to the valve body 45 via a rod 47 so as to move integrally therewith, and a diaphragm 46 is installed in the atmospheric pressure chamber 43b.
A spring 48 for urging the valve in the valve opening direction (the direction in which the valve body 45 connects the first and second pressure chambers 42, 43) is contracted. The first pressure chamber 42 is sucked into the communication passage 37 (a predetermined gap between the front housing 25 and the side housing 23 in the compressor body 20) via the communication passage 49 and in the second pressure chamber 43. The pressure chambers 43a are respectively communicated with the suction chambers 29, and the atmospheric pressure chambers 43b of the second pressure chambers 43b.
Is open to the atmosphere, and when the biasing force of the refrigerant suction pressure in the suction pressure chamber 43a against the diaphragm 46 is larger than the biasing force of the atmospheric pressure in the atmospheric pressure chamber 43b plus the spring force of the spring 48 therein. , The diaphragm 46 is moved downward in FIG. 4, and the valve body 45 integrated with the diaphragm 46 closes the valve opening 41, thereby blocking the communication between the first pressure chamber 42 and the suction chamber 29, while Diaphragm when small
46 is moved upward in the figure to open the valve port 41, and the first pressure chamber
42 and the suction chamber 29 are made to communicate with each other. Therefore, the spool valve 32 and the pressure regulator 40 automatically control the opening / closing of the bypass passages 39, 39 in accordance with the suction pressure of the compressor body 20 so that the refrigerant suction pressure of the compressor body 20 is kept substantially constant. When the engine speed is low and its ability is low,
Close the pressure regulator 40 and spool valve
By increasing the pressure in the pressurizing chamber 36 of 32, the bypass passage 3
By closing 9,39, the capacity of the compressor 2 is kept at the maximum capacity, while when the capacity of the compressor 2 increases due to an increase in the rotation speed of the compressor 2, the pressure regulator 40 opens due to the pressure drop in the suction chamber 29 accompanying it. Along with the valve opening operation, the pressurizing chamber in the spool valve 32
The capacity of the compressor 2 is increased by lowering the pressure in the valve 36 and moving the valve element 34 upward in the figure, and opening the bypass passages 39, 39 to bypass the gas refrigerant to the suction side. The variable capacity mechanism 50 is configured so as to reduce the excess capacity when the capacity of the compressor 2 is increased more than the heat load in the vehicle compartment.

Further, the first pressure chamber of the pressure regulator 40
A communication passage 49 for communicating 42 with the communication passage 37 and a suction chamber 29 in the front housing 25 are communicated with each other by a communication passage 51. The communication passage 51 has a normally closed solenoid valve SV for opening and closing the communication passage 51. Is provided, and in the closed state of this solenoid valve SV,
While the variable capacity mechanism 50 is operated to bring the compressor 2 into the internal capacity control state, when the solenoid valve SV is opened,
The variable displacement mechanism 50 is deactivated, the pressure in the suction chamber 29 is set to an intermediate pressure, and the valve element 34 of the spool valve 32 is positioned at the rising end position in the figure by the spring force of the spring 38, and the bypass passages 39, 39 are fully opened. The capacity setting mechanism 52 is configured to fix the capacity of the compressor 2 to the minimum capacity by maintaining the bypass amount of the refrigerant at the maximum by maintaining the capacity.

Then, as shown in FIG. 2, the operation of the solenoid valve SV is controlled by the control unit 100. The control unit 100, the output signal of the throttle sensor 101 for detecting the throttle opening of the engine 12,
The running speed of a car is a predetermined speed near zero (for example, 5 km /
h) ON of the vehicle speed detection switch SW ₁ that turns ON when:
OFF signal and transmission range of the above transmission is D
The ON / OFF signal of the D range switch SW ₂ for switching to the range (normal driving range) is input.

The detailed configuration of the control unit 100 will be described with reference to FIG. The throttle sensor 101 is composed of a potentiometer, and is originally provided for controlling the fuel injection amount with respect to the engine 12 and controlling the operation of the transmission, and its output signal is an EGI control unit for fuel injection control. 102,
It is input to the EAT control unit 103 for transmission control.

The output signal of the throttle sensor 101 is also input to the comparator 104.In this comparator 104, the throttle opening detected by the throttle sensor 101 and its set reference value are compared, and the throttle opening is When it is determined that the state is substantially fully closed below the reference opening, the comparator 104 outputs the Hi level signal. This comparator 104
The output of is connected to the transistor Tr
The above D range switch SW ₂ is connected to the collector of
The vehicle speed detection switch SW ₁ is connected to the D range switch SW ₂ . The D range switch SW ₂ is a control unit 10 for controlling the transmission.
3 and a D range indicator 105 that lights up to indicate that the transmission has been switched to the D range. On the other hand, the emitter of the transistor Tr is the relay 106.
Is connected to the solenoid 106a, and the relay switch 106b of the relay 106, which is always off, is connected to the solenoid valve SV.

Therefore, in the present embodiment, the throttle sensor 101,
Based on the respective operating states of the vehicle speed detection switch SW ₁ and the D range switch SW _2, a state in which the vehicle is considered to be in a stopped state for a short time is determined, and the throttle opening detected by the throttle sensor 101 is compared. It is determined by the comparison at the device 104 that the transistor Tr is in a substantially fully closed state, the transistor Tr is turned on by the Hi level signal from the comparator 104, and the vehicle speed is substantially zero because the vehicle speed detection switch SW ₁ is turned on. When it is determined that the transmission is in the D range due to the ON operation of the D range switch SW ₂ , it is determined that the vehicle is in a stopped state for a short time due to, for example, waiting for a signal. The vehicle stop detection means 107 is configured to detect that the vehicle is in a state in which it can be considered that the vehicle has stopped traveling for a short time.

In addition, the comparator 104, the transistor Tr and the relay 106.
Thus, based on the output of the vehicle stop detection means 107, when the vehicle stop detection means 107 detects a state that can be regarded as a short stop of the traveling of the vehicle, outputs an operation signal to the solenoid valve SV, the compressor The control means 108 is configured to control so that the No. 2 is kept in the minimum capacity operating state.

 Next, the operation of the above embodiment will be described.

Basically, when the operation switch of the air conditioner 1 is turned on, the compressor 2 is operated, the gas refrigerant discharged from the compressor 2 is condensed by the condenser 3 to become a liquid refrigerant, and this liquid refrigerant is an expansion valve. After being expanded by 5, vaporized in the evaporator 6, then taken into the compressor 2, and the interior of the vehicle is cooled by the heat of vaporization of the refrigerant in the evaporator 6.

During operation of such an air conditioner 1, the throttle sensor 10
The throttle opening is detected by 1. Further, the vehicle speed detection switch SW ₁ detects whether the vehicle speed is below a predetermined value, and the D range switch SW ₂ detects whether the transmission shift range is the D range. Then, in the vehicle stop detection means 107, the detected throttle opening is not in a substantially fully closed state, the vehicle speed is higher than a predetermined value, and the vehicle speed detection switch SW ₁ is in an OFF state, and the transmission is operated in a range other than the D range. If any one of the three conditions that the D range switch SW ₂ is in the OFF state is satisfied by the switching holding, that state is regarded as the running state of the automobile. At this time, the solenoid valve SV of the compressor 2 is kept closed, and the compressor 2 is operated in the displacement control state by the operation of the variable displacement mechanism 50. That is, when the rotational speed of the compressor 2 is low and its capacity is low, the pressure regulator 40 is closed, and the bypass passages 39, 39 are closed by the increase in the pressure in the pressurizing chamber 36 of the spool valve 32, so that the compressor is closed. When the capacity of No. 2 is maintained at the maximum capacity while its capacity is increased due to the increase in the rotation speed of the compressor 2, the pressure regulator 40 is opened due to the pressure decrease in the suction chamber 29, and the valve opening operation is performed. Accordingly, the pressure in the pressurizing chamber 36 of the spool valve 32 decreases, the valve body 34 moves to open the bypass passages 39, 39, and the gas refrigerant is bypassed to the suction side inside the compressor 2. , The capacity of the compressor 2 is controlled so as to decrease in accordance with the increase in the rotation speed.

On the other hand, the throttle opening detected by the throttle sensor 101 is in a substantially fully closed state, and the vehicle speed detection switch SW ₁ is in the ON operation due to the decrease of the vehicle speed to a predetermined value or less, so that the transmission is moved to the D range. D by holding
When the range switch SW ₂ is ON, that state is considered to be a state in which the vehicle has stopped traveling for a short time due to waiting for a signal or the like. Then, at that time, by the control means 108 receiving the output of the vehicle stop detection means 107,
The solenoid valve SV is opened, the operation of the variable capacity mechanism 50 is stopped, the pressure in the suction chamber 29 becomes an intermediate pressure, and the valve element 34 of the spool valve 32 is positioned at the rising end position in FIG. By holding the bypass passages 39, 39 in the fully opened state, the bypass amount of the refrigerant to the suction chamber 29 side is maximized, whereby the capacity of the compressor 2 is fixed to the minimum capacity. This fixed holding of the compressor 2 to a minimum capacity reduces the output of the engine 12 that is consumed for driving the compressor 2, and the load on the engine 12 can be small. Therefore, the idling vibration of the engine 12 when the vehicle is stopped for a short time is effective. Can be reduced to When the compressor 2 is kept in the minimum capacity state when the vehicle is stopped, the capacity of the air conditioner 1 is reduced, but since the vehicle is stopped for a short time, it does not adversely affect the driver inside the vehicle.

In the above-described embodiment, a through-vane compressor is used as the variable displacement compressor 2. However, other types of variable displacement compressors, such as a swash plate compressor, may be used.

(Effects of the Invention) As described above, according to the present invention, in the vehicle air conditioner, the compressor driven by the vehicle-mounted engine can be selected between the variable capacity operating state and the minimum capacity operating state according to the suction pressure of the refrigerant. Variable capacity compressor,
If it is detected that the vehicle is stopped for a short period of time, the throttle opening of the engine and the vehicle speed are both below a predetermined value and the on-vehicle transmission is in the forward gear position, Since it was considered that the vehicle stopped for a short time due to signal waiting, the internal capacity control of the compressor was prohibited, and the capacity was fixed and maintained at the minimum capacity state. The load of the engine in the idling state can be reduced while making use of the automatic control of the capacity, so that the idling vibration of the engine when the vehicle is stopped for a short time can be effectively reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention. FIG. 2 and subsequent drawings show an embodiment of the present invention, FIG. 2 is an overall configuration diagram, FIG. 3 is a developed sectional view showing a variable displacement mechanism of a compressor, FIG. 4 is its schematic sectional view, and FIG. FIG. 3 is an electric circuit diagram showing the configuration of a control unit. 1 ... Air conditioner, 2 ... Compressor, 12 ... Engine, 21 ... Suction port, 22 ... Discharge port, 32 ... Spool valve, 40 ... Pressure regulator, 50 ... Variable capacity mechanism, SV ... Solenoid valve, 52 …… Volume setting mechanism, 100 ……
Control unit, 101 ... Throttle sensor, 107
…… Vehicle stop detection means, 108 …… Control means, SW ₁ …… Vehicle speed detection switch, SW ₂ …… D range switch.

Claims (1)

(57) [Claims] 1. A suction port for sucking a refrigerant, a discharge port for discharging a refrigerant that has been sucked from the suction port and passed through a compression stroke, and a variable capacity mechanism for controlling the discharge amount of the refrigerant according to the suction pressure of the refrigerant. An external control device for externally controlling a variable capacity compressor for an air conditioner driven by an engine mounted on a vehicle, wherein the compressor has a capacity setting for keeping the discharge amount of the refrigerant to a minimum. A mechanism is provided, and it can be considered that the vehicle is stopped for a short time.The throttle opening of the engine and the vehicle speed are both below a predetermined value and the in-vehicle transmission is in the forward gear position. When the vehicle stop detection means for detecting and the output of the vehicle stop detection means detect a state that can be regarded as a short stop of traveling of the vehicle by the vehicle stop detection means, External control device for a variable displacement compressor characterized by comprising a control means for actuating the volume setting mechanism of the serial compressors.