JP3961108B2 - Clutch control device for externally controlled variable displacement compressor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for controlling a clutch of an externally controlled variable displacement compressor provided with a control means for controlling a control pressure for changing a discharge capacity based on an electric signal from the outside, and in particular, intended to save power. About.
[0002]
[Prior art]
Recently, variable capacity compressors that can change the refrigerant discharge capacity according to the required amount of cooling capacity to meet the needs for power saving for car air conditioners and comfort needs such as blowing air temperature change and shock reduction during compressor ON / OFF control Is becoming widespread. For example, taking a swash plate type variable displacement compressor as an example, the piston stroke is changed by continuously changing the inclination of the swash plate in accordance with the heat load in the cooling space, so that the capacity is continuously changed. . In this case, if the inclination of the swash plate is large, the discharge amount is large (during maximum cooling), and if the inclination is small, the discharge amount is also small (during capacity control). As described above, since the refrigerant circulation amount decreases except during the maximum cooling, the required power of the compressor decreases.
[0003]
In such a variable displacement compressor, as a control method for changing the capacity (for example, changing the inclination of the swash plate in the case of a swash plate type), control is generally performed using a so-called mechanical control valve (MCV). is there. This mechanical control valve is a valve (for example, a bellows type control valve) provided in the compressor body, and internally performs variable control of the capacity using the suction pressure of the compressor. For example, when a bellows type control valve is installed in a swash plate type variable displacement compressor, the bellows contracts and expands due to a change in the suction pressure that changes according to the thermal load of the compressor (the magnitude relationship with the set pressure). Open and close the high pressure side valve leading to the compressor discharge side and the low pressure side valve leading to the inside of the crankcase and the suction side of the compressor, thereby controlling the pressure (control pressure) in the crankcase, The inclination of the swash plate is changed by changing the balance of the pressure applied to the piston resulting from the pressure difference between the cylinder and the crankcase.
[0004]
However, the variable displacement control of such a variable displacement compressor is mechanical control based on characteristics using a mechanical control valve such as a bellows type, so continuous control is possible, but power saving etc. It was difficult to perform the complicated control intended.
[0005]
On the other hand, there is an externally controlled variable capacity compressor provided with an electronically operated control valve (ECV) such as an electromagnetic valve that can be externally controlled by an electrical signal. According to this, since control can be performed from the outside by software, optimum control of the compressor becomes possible.
[0006]
[Problems to be solved by the invention]
However, in such an externally controlled variable capacity compressor that performs complicated control by an electric signal from the outside, the driving torque of the compressor varies according to the various control contents, but is driven by the engine. In the variable capacity compressor, there has been no particular prediction about the driving torque of the compressor that becomes the engine load.
[0007]
In addition, when the compressor is operating, it is assumed that the power supply to the clutch coil for transmitting or not transmitting the driving force from the automobile engine to the compressor drive shaft is the maximum engine load. , It was set higher.
[0008]
Therefore, when the compressor is operated, a suction force more than necessary is generated, and electric power is wasted. In addition, there is a problem that the loss of energy leads to deterioration of fuel consumption.
[0009]
The present invention has been made in view of the above-described problems of the prior art, and predicts the driving torque of an externally controlled variable displacement compressor that is controlled by an electric signal from the outside, and the compressor clutch that matches this torque. The purpose is to save power by using the power supply.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, an invention according to claim 1 is provided with a control means for controlling a control pressure for changing a discharge capacity based on an electric signal from the outside, and an external which constitutes a refrigeration cycle of an automotive air conditioner. A clutch control device for a control type variable displacement compressor, comprising: temperature detection means for detecting a high-pressure side saturation temperature of the refrigeration cycle; suction pressure detection means for detecting suction pressure of the variable displacement compressor; and the temperature detection means. calculating means for calculating an estimated value of the driving torque of the variable capacity compressor based on the detected suction pressure by the detected high pressure side saturation temperature and the suction pressure detection means, the estimation of the calculated driving torque by the calculating means For transmitting or interrupting the driving force from the external driving means to the variable displacement compressor based on the value Possess control means for controlling the supply of power to the latch, wherein the temperature detecting means is characterized Rukoto are integrally disposed in the connector of the pressure switch attached to the liquid tank constituting the refrigeration cycle .
[0011]
According to a second aspect of the present invention, in the clutch control device for an externally controlled variable displacement compressor according to the first aspect, the calculation means is configured to perform the variable displacement based on the high-pressure side saturation temperature, the suction pressure, and the electric signal. An estimated value of the driving torque of the compressor is calculated.
[0012]
According to a third aspect of the invention, the clutch control device of the external control type variable displacement compressor according to the first aspect, wherein the temperature detecting means (44) is electrically connected in series with the pressure switch (45) It is characterized by that .
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram for explaining a system configuration of a clutch control device of an externally controlled variable displacement compressor according to an embodiment of the present invention.
[0018]
This system has a refrigeration cycle 1 mounted on an automotive air conditioner (car air conditioner). The refrigeration cycle 1 is configured by connecting an externally controlled variable capacity compressor 2, a condenser 3, a liquid tank 4, an expansion valve 5, an evaporator 6 and the like by piping and enclosing a refrigerant therein. The externally controlled variable capacity compressor 2 is selectively driven by an engine (not shown) via a belt, a pulley 7 and a clutch 11 (not shown), and sucks and compresses low-temperature and low-pressure gas refrigerant evaporated by the evaporator 6 at the time of driving. Then, the high-temperature and high-pressure gas refrigerant is pumped to the condenser 3, and the refrigerant is repeatedly circulated through the condenser 3 and the evaporator 6. A condenser fan 8 is attached to the condenser 3, and the condenser 3 cools and condenses the high-temperature and high-pressure gas refrigerant sent from the compressor 2 by heat exchange with the cooling air supplied by the condenser fan 8. . A liquid tank 4 provided between the condenser 3 and the expansion valve 5 gas-liquid separates the refrigerant liquefied by the condenser 3 to temporarily store the liquid refrigerant, and sends only the liquid refrigerant to the expansion valve 5. In the case of a temperature-type expansion valve 5 that is generally used, the medium-temperature and high-pressure liquid refrigerant that has passed through the liquid tank 4 is decompressed and expanded to form a low-temperature and low-pressure mist-like refrigerant, and downstream of the evaporator 6. The refrigerant flow rate is adjusted so that the evaporation state of the refrigerant has an appropriate degree of superheat at the evaporator outlet by feedback of a temperature sensing cylinder (not shown) provided in FIG. The evaporator 6 evaporates the mist-like refrigerant liquefied by the condenser 3 and becomes low-temperature and low-pressure by the expansion valve 5, and causes the air sent by a blower fan (not shown) to flow outside to exchange heat with the mist-like refrigerant. As a result, the air blown into the passenger compartment is cooled and simultaneously dehumidified.
[0019]
The external control type variable displacement compressor 2 is, for example, a swash plate type external control type variable displacement compressor, and the inclination of the swash plate can be controlled from the outside by an electric signal. That is, this externally controlled variable displacement compressor 2 includes an electronically operated control valve (ECV) 9 such as an electromagnetic valve that can be externally controlled by an electric signal, instead of the conventional mechanical control valve (MCV), as a control means. ing. For example, when a solenoid valve that communicates with the high pressure side is used as the ECV 9, the inside of the crankcase and the low pressure side communicate with each other through a passage having a predetermined opening, and the pressure in the crankcase escapes to the low pressure side. ing. Therefore, by controlling the pressure in the crankcase (control pressure) by turning on and off the solenoid valve 9 to introduce / shut off the high-pressure side pressure, the balance of the pressure applied to the piston is changed, and the inclination of the swash plate Thus, the discharge capacity of the compressor 2 can be controlled.
[0020]
At this time, the electromagnetic valve 9 had an appropriate duty ratio (a value obtained by dividing the pulse width in the pulse wave by the period) as an external electric signal, for example, from an autoamplifier 10 described later. A duty signal is provided. When it is necessary to reduce the capacity (tilt of the swash plate), a duty signal having a large duty ratio is given to increase the opening time of the solenoid valve 9 to increase the pressure in the crankcase (control pressure). When the capacity (tilt of the swash plate) needs to be increased, a duty signal having a small duty ratio is given to shorten the valve opening time of the solenoid valve 9 to reduce the pressure (control pressure) in the crankcase. Let
[0021]
This externally controlled variable capacity compressor 2 is controlled by an auto amplifier 10. Here, only the components necessary for controlling the clutch of the compressor are shown. That is, the autoamplifier 10 includes a high-pressure side pressure sensor (high-pressure transducer) 15 as discharge pressure detection means for detecting the discharge pressure of the externally controlled variable capacity compressor 2, and a low-pressure side pressure sensor (low pressure) as suction pressure detection means. Transducer) 16 and the like are connected. The high pressure side pressure sensor 15 is attached to a high pressure pipe between the capacitor 3 and the compressor 2 and converts the high pressure side pressure of the refrigerant into an electric signal. The discharge pressure of the compressor 2 is indicated by this high-pressure side pressure. Note that the high pressure side pressure sensor 15 may be attached to a high pressure pipe between the capacitor 3 and the expansion valve 5, and this high pressure side pressure may be detected as an alternative to the discharge pressure of the compressor 2. The low pressure side pressure sensor 16 is attached to a low pressure pipe between the evaporator 6 and the compressor 2 and converts the low pressure side pressure of the refrigerant into an electric signal. The suction pressure of the compressor 2 is indicated by this low pressure.
[0022]
The auto-amplifier 10 includes a temperature control switch, a passenger compartment air temperature sensor, a passenger compartment air temperature sensor, a solar radiation amount sensor, an evaporator downstream air temperature sensor, and an engine serving as a heating source that are operated by a built-in microcomputer by a passenger (not shown). Input signals from each switch and sensor such as the temperature sensor of the cooling water are processed to determine the duty ratio, which is a control parameter, so that the required compressor discharge capacity is obtained. It outputs to the electromagnetic valve (ECV) 9 of the variable capacity compressor 2.
[0023]
Here, when the compressor discharge pressure is Pd, the compressor suction pressure is Ps, the duty ratio is R, and the compressor drive torque is Tr, the following relationship is established.
f (Tr) = f (Pd, Ps, R)
However, f shows a function. Specifically, the relationship between Tr, Pd, Ps, and R can be obtained in advance by experiments, and it can be seen that there is a relationship as shown in FIG. Using this relationship, the autoamplifier 10 calculates an estimated value of the compressor driving torque Tr from the compressor discharge pressure Pd, the compressor suction pressure Ps, and the duty ratio R as predetermined feature amounts during operation of the compressor. To do.
[0024]
The autoamplifier 10 is connected to a clutch 11 for transmitting or blocking driving force from an automobile engine as external driving means to a driving shaft (not shown) of the compressor 2. The autoamplifier 10 is configured to control power supply to the clutch 11 based on the calculated estimated value of the drive torque Tr. In general, a magnet clutch is used as the clutch 11. The clutch 11 includes a clutch plate that is disposed on the front surface of the pulley 7 that is a rotor and has a rotary shaft directly coupled to the drive shaft of the compressor 2, and a coil that is disposed on the opposite side of the clutch plate across the pulley 7. (Not shown). The clutch plate is attracted and attracted to the pulley 7 by the magnetic force generated by energizing the coil of the clutch 11. Therefore, specifically, the autoamplifier 10 controls the voltage applied to the coil of the clutch 11 based on the calculated estimated value of the driving torque Tr.
[0025]
Note that, as described above, the autoamplifier 10 has both the configuration of a calculation unit that calculates an estimated value of the drive torque Tr and a control unit that controls power supply to the clutch 11.
[0026]
Of course, in addition to the above, the autoamplifier 10 performs normal control for the automotive air conditioner. That is, other switches and sensors (not shown) such as a fan switch and an engine coolant temperature sensor serving as a heating source are further connected to the auto amplifier 10. The auto amplifier 10 is connected to a built-in microcomputer. , These sensors, air mix PBR (built in air mix door actuator), and signals such as each switch are processed, each actuator (intake door actuator, air mix door actuator, mode door actuator), fan control amplifier, By operating the compressor 2 (the clutch 11 for transmitting or interrupting the driving force from the pulley 7), the inlet position, the outlet air temperature, the outlet position, the outlet air amount, and the ON / OFF state of the compressor 2 itself A comprehensive Also it has a function of controlling.
[0027]
The present embodiment is configured as described above, and the clutch control operation of the compressor will be described below.
[0028]
First, when a compressor operation command such as an air conditioner switch or defrost switch (not shown) is issued, the clutch 11 of the externally controlled variable displacement compressor 2 is turned on, and the driving force of the automobile engine is supplied to the compressor 2 via the belt, pulley 7 and clutch 11. Is transmitted to the drive shaft. Thereby, the refrigerant in the refrigeration cycle 1 is circulated and a predetermined air conditioning operation is started. The autoamplifier 10 calculates an input signal from the temperature adjustment switch, the temperature outside the passenger compartment, the inside air temperature, and the like, and determines the duty ratio R that is a control parameter. The autoamplifier 10 outputs the calculated predetermined duty ratio R to the solenoid valve 9 to introduce / shut off the high-pressure side pressure and control the pressure in the crankcase to change the inclination of the swash plate. Thereby, the discharge capacity of the compressor 2 is controlled.
[0029]
Further, the discharge pressure Pd detected by the high pressure side pressure sensor 15 and the suction pressure Ps signal detected by the low pressure side pressure sensor 16 are input to the auto amplifier 10. The autoamplifier 10 estimates the driving torque of the compressor based on the relationship between the discharge pressure, the suction pressure, the duty ratio, and the driving torque of the compressor that are obtained in advance through experiments shown in FIG. That is, as shown in the right part of FIG. 2, the duty ratio in the steady state is determined from the detected discharge pressure and suction pressure, and based on these, the externally controlled variable capacity compressor is derived from the relationship of the left part of FIG. Can be accurately predicted with a simple configuration.
[0030]
As can be seen from FIG. 2, when a certain discharge pressure Pd is determined, the suction pressure Ps is determined by the duty ratio R. As a result, the compressor drive torque Tr is determined by the discharge pressure Pd and the suction pressure Ps. An estimation can be made. However, the duty ratio R is output as a control parameter to the electromagnetic valve (ECV) 9 of the externally controlled variable displacement compressor 2, and causes the numerical values of the discharge pressure Pd and the suction pressure Ps to change. Therefore, by considering this duty ratio R, it becomes possible to estimate the driving torque Tr of the compressor more quickly and accurately in consideration of the transition trend of the torque.
[0031]
Here, the auto amplifier 10 controls the clutch 11 based on the estimated value of the compressor driving torque Tr thus obtained. That is, the auto amplifier 10 outputs a signal for applying a predetermined voltage corresponding to the driving torque Tr of the compressor to the coil of the clutch 11.
[0032]
FIG. 3 is a diagram illustrating a relationship between the driving torque Tr of the compressor and the voltage V applied to the coil of the clutch 11. The voltage indicated by the broken line in FIG. 3 is the conventional voltage, and the voltage indicated by the solid line is according to the present embodiment. Therefore, the area indicated by the diagonal line in FIG. As described above, since the applied voltage to the magnet net coil of the clutch 11 is adjusted according to the estimated value of the driving torque Tr of the compressor as the engine load, the torque necessary for driving the compressor is secured. Thus, efficient power supply to the clutch 11 becomes possible.
[0033]
For this reason, it is possible to prevent unnecessary power from being generated by generating more suction force than necessary, and power saving can be achieved. In addition, the fuel saving performance is improved by preventing the deterioration of the fuel consumption due to the energy loss such as the electric power cost. Furthermore, since the voltage applied to the coil of the clutch is reduced as a whole, the reliability durability of the coil is improved.
[0034]
FIG. 4 is a block diagram for explaining a system configuration of a clutch control device for an externally controlled variable displacement compressor according to another embodiment of the present invention, and FIG. 5 shows a liquid tank to which a pressure switch with a temperature sensor is attached. FIG. 6 is a circuit diagram showing a connection method between the pressure switch and the temperature sensor.
[0035]
This embodiment is different from the above embodiment in that the high pressure side saturation temperature TL on the refrigeration cycle 1 is detected instead of the discharge pressure Pd. However, since the other points are the same, members that are the same as those shown in FIG. 1 are assigned the same reference numerals, and descriptions thereof are omitted.
[0036]
As shown in FIGS. 4 and 5, a pressure switch 43 with a temperature sensor is attached to the end plate 41 of the liquid tank 4 so as to face the gas-liquid mixing unit 42. The temperature sensor 44 is disposed integrally with the pressure switch 45 in the connector on the distal end side of the pressure switch 43 with the temperature sensor. Preferably, the temperature of the refrigerant is set to be thermally conductive to protect the temperature sensor itself. It is comprised so that it can detect via the heat-transfer member 44a which consists of a favorable metal plate.
[0037]
As the temperature sensor 44, for example, a thermistor is used, and connected to the pressure switch 45 in series as shown in FIG. The pressure switch 45 detects an abnormal increase (Hi side) and abnormal decrease (Lo side) of the high-pressure side pressure. Therefore, the temperature sensor 44, which is a thermistor, is normally used to estimate the driving torque of the compressor, which will be described later, with its resistance value as a voltage. Further, when the pressure switch 45 is operated, the contact 45a of the pressure switch 45 is separated, so that the pressure switch 45 can be reliably cut without delay of time constant as compared with the case where the pressure sensor 45 is cut. Here, “cut” means to disconnect the clutch and stop the compressor.
[0038]
When the pressure switch 45 is operated by high pressure (Hi side) and the resistance value of the circuit becomes ∞, the amplifier has a high pressure, so that the compressor driving torque is high. Determined. On the other hand, when the pressure switch 45 is operated by low pressure (Lo side), the driving torque of the compressor is determined to be high torque although it is low torque, resulting in high (Hi) idling. Therefore, it is necessary to determine whether it is cut on the Lo side or the Hi side by looking at the state before the pressure is cut.
[0039]
FIG. 7 is a graph showing the relationship between the high-pressure side saturation temperature TL and the discharge pressure Pd of the compressor. As can be seen, there is a fairly stable correlation between these two. Therefore, even when this high-pressure side saturation temperature TL is used instead of the discharge pressure Pd, the driving torque of the externally controlled variable displacement compressor can be accurately predicted with a simple configuration as in the above-described embodiment. .
[0040]
In particular, according to the present embodiment, since the pressure switch and the temperature sensor are integrated so as to perform two functions, it is not necessary to newly install a harness for connection to the amplifier, In order to attach the temperature sensor, there is no need for processing on the other side of the attachment. Further, since the temperature sensor is less expensive than the high pressure side pressure sensor (high pressure transducer), there is an advantage that the driving torque of the compressor can be estimated at a low cost. Furthermore, the function as a pressure switch can be ensured as before. However, in the system shown in FIG. 4, the temperature sensor and the pressure switch are integrated as described above. However, the temperature sensor is attached to the refrigerant pipe separately from the pressure switch, for example, on the high pressure side. A configuration for detecting the saturation temperature TL is also possible.
[0041]
The embodiments described above are not described for limiting the present invention, and various modifications can be made by those skilled in the art within the technical idea of the present invention. For example, the estimation of the drive torque of the externally controlled variable displacement compressor is not limited to the method described in the above embodiment, and may be performed based on other predetermined feature values when the variable displacement compressor is operated. Good.
[0042]
【The invention's effect】
As described above, according to the first aspect of the present invention, the power supply to the clutch is controlled based on the estimated value of the drive torque of the externally controlled variable capacity compressor. It is possible to efficiently supply electric power while ensuring the torque necessary for driving. For this reason, it is possible to prevent an unnecessary amount of power from being wasted and to save power. In addition, the fuel saving performance is improved by preventing the deterioration of the fuel consumption of the automobile engine or the like due to the energy loss of the electric power cost. Furthermore, the amount of power supplied to the clutch is reduced as a whole, and the reliability and durability of the clutch is improved.
Furthermore, it is possible to predict the driving torque of the externally controlled variable displacement compressor with a simple configuration with high accuracy and at low cost, and to supply power to the clutch more efficiently.
Furthermore, there is no need for processing on the other side of the attachment to attach the temperature sensor, and the function as a pressure switch can be ensured as before.
[0043]
According to the second aspect of the present invention, it is possible to estimate the driving torque of the compressor more quickly, accurately and at a lower cost in consideration of the transition trend of the torque. Supply can be made.
[0044]
According to the third aspect of the present invention, since the pressure switch and the temperature sensor are connected in series and integrated so as to perform two functions, it is not necessary to newly install a harness.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a system configuration of a clutch control device for an externally controlled variable displacement compressor according to an embodiment of the present invention.
FIG. 2 is a diagram showing a relationship among a compressor discharge pressure Pd, a compressor suction pressure Ps, a duty ratio R, and a compressor drive torque Tr;
FIG. 3 is a diagram showing a relationship between compressor driving torque Tr and voltage V applied to a clutch coil.
FIG. 4 is a block diagram for explaining a system configuration of a clutch control device of an externally controlled variable displacement compressor according to another embodiment of the present invention.
FIG. 5 is a cross-sectional view showing a liquid tank to which a pressure switch with a temperature sensor is attached.
FIG. 6 is a circuit diagram illustrating a connection method between a pressure switch and a temperature sensor.
FIG. 7 is a diagram showing a relationship between a high-pressure side saturation temperature TL and a compressor discharge pressure Pd.
[Explanation of symbols]
1 ... refrigeration cycle,
2 ... Externally controlled variable displacement compressor,
4 ... Liquid tank,
9 ... Solenoid valve (control means),
10: Auto amplifier (calculation means, control means),
11 ... Clutch,
15 ... high pressure side pressure sensor (discharge pressure detecting means),
16 ... Low pressure side pressure sensor (suction pressure detection means),
44 ... temperature sensor (temperature detection means),
45 ... Pressure switch,
50. Engine control amplifier (fuel supply adjusting means).

Claims (3)

Clutch of an externally controlled variable displacement compressor (2) comprising control means (9) for controlling the control pressure for changing the discharge capacity based on an external electric signal and constituting the refrigeration cycle (1) of the air conditioner for automobiles A control device,
Temperature detecting means (44) for detecting the high-pressure side saturation temperature of the refrigeration cycle (1) ;
Suction pressure detection means (16) for detecting the suction pressure of the variable capacity compressor (2) ;
Calculation for calculating the estimated value of the driving torque of the variable capacity compressor based on the detected suction pressure by the detected high pressure side saturation temperature and the suction pressure detection means (16) (2) by said temperature detecting means (44) Means,
Control means for controlling power supply to the clutch (11) for transmitting or shutting off the driving force from the external driving means to the variable displacement compressor (2) based on the estimated value of the driving torque calculated by the calculating means and, the possess,
Said temperature detecting means (44), the refrigeration cycle (1) External control type variable, characterized in Rukoto are integrally disposed in the connector of the pressure switch mounted (45) to the liquid tank (4) which constitutes the A clutch control device for a capacity compressor. 2. The external control expression according to claim 1 , wherein the calculating means calculates an estimated value of a driving torque of the variable capacity compressor (2) based on the high-pressure side saturation temperature, the suction pressure, and the electric signal. Clutch control device for variable displacement compressor. The clutch control device for an externally controlled variable displacement compressor according to claim 1, wherein the temperature detecting means (44) is electrically connected in series to the pressure switch (45) .

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