KR101156378B1 - Method for controlling air conditioner of vehicle - Google Patents

Abstract

 The present invention relates to a control method for a vehicle air conditioner, wherein a target control value for a pressure regulating valve for changing a swash plate inclination angle of a variable displacement swash plate compressor is variable according to a magnitude of a temperature deviation between a target evaporator temperature and an actual evaporator temperature. It aims at controlling the discharge capacity of a compressor efficiently by controlling in this way.

A control method of a vehicle air conditioner according to the present invention includes the steps of setting a target evaporator temperature; Calculating a temperature deviation between the target evaporator temperature and the actual evaporator temperature; Variably setting a control coefficient in accordance with the magnitude of the temperature deviation; Calculating a target control value of the pressure regulating valve of the variable displacement swash plate compressor using the control coefficient; And controlling the pressure regulating valve using the target control value.

Air Conditioning, Air Conditioning, Air Conditioning Control, Variable Compressor, Proportional Integral Control, Compressor Control

Description

Control method of vehicle air conditioner {METHOD FOR CONTROLLING AIR CONDITIONER OF VEHICLE}

1 is a cross-sectional view showing an example of a variable displacement swash plate compressor.

2 is a configuration diagram of an air conditioning system for performing a control method according to the present invention.

3 is a flowchart illustrating a control method of the vehicle air conditioner according to the present invention.

4A is a graph showing an example of calculating the proportional gain according to the evaporator temperature deviation.

4B is a graph showing an example of calculating the integral gain according to the evaporator temperature deviation.

4C is a graph showing an example of calculating the proportional gain or the integral gain according to the evaporator temperature deviation.

5 is a flowchart showing a method of setting a target evaporator temperature.

<Description of the symbols for the main parts of the drawings>

100: variable displacement swash plate compressor, 160: pressure control valve,

212, 214, 216: Vent, 310: Sensor.

The present invention relates to a control method of a vehicle air conditioner, and in particular, a target control value for a pressure regulating valve for changing a swash plate inclination angle of a variable displacement swash plate compressor according to a magnitude of a temperature deviation between a target evaporator temperature and an actual evaporator temperature. By controlling variably, the present invention relates to a control method for a vehicle air conditioner that can efficiently control a discharge capacity of a compressor.

In the variable displacement swash plate compressor, the inclination angle of the swash plate can be adjusted by varying the pressure of the refrigerant by the pressure control valve according to the load. By changing the stroke distance of the piston by adjusting the inclination angle of the swash plate, the discharge capacity of the refrigerant can be adjusted, and the evaporator temperature is adjusted according to the change of the discharge capacity of the refrigerant.

The pressure regulating valve can be divided into an internal control type and an external control type. The structure of such a variable displacement swash plate compressor is well disclosed in Japanese Patent Laid-Open No. 2001-107854.

The output (Duty, ie, current value) for the pressure regulating valve calculates a deviation between the target evaporator temperature and the actual evaporator temperature, and can be controlled by a control method such as proportional-integral (PI) control based on the deviation. . As an example, Japanese Laid-Open Patent Publication No. 2003-200730, for example, performs proportional-integral control when the deviation between the target evaporator temperature and the actual evaporator temperature is within 3 ° C, and the actual evaporator temperature is 3 ° C or more compared to the target evaporator temperature. A technique is disclosed for performing maximum capacity control if high and for performing minimum capacity control if the actual evaporator temperature is less than 3 ° C. below the target evaporator temperature.

When performing proportional-integral control by feeding back the actual evaporator temperature to the target evaporator temperature, the temperature control performance, namely temperature convergence and response time, depends on the proportional gain and integral gain depending on the system. ) Depends on how appropriately selected. In general, the larger the gain, the faster the response speed, but excessive overshoot and undershoot occur, which tends to impair stability. On the contrary, when the gain is made small, the temperature convergence is excellent, but it takes a long time to stabilize. In this regard, when the deviation of the evaporator temperature is above and below a predetermined value as in the prior art, when the maximum capacity control and the minimum capacity control are uniformly performed, there is a problem that the evaporator temperature and the system become unstable.

SUMMARY OF THE INVENTION An object of the present invention is to control the discharge capacity of a compressor by controlling the target control value for the pressure regulating valve which changes the swash plate inclination angle of the variable displacement swash plate compressor in accordance with the temperature deviation between the target evaporator temperature and the actual evaporator temperature. It is to provide a control method of the vehicle air conditioner for efficient control.

Another object of the present invention is to set a large control coefficient (i.e., Proportional Gain and Integral Gain) when the temperature deviation between the target evaporator temperature and the actual evaporator temperature is large, to quickly reach the target evaporator temperature. When the temperature deviation is small, the control coefficient is set small so that the target evaporator temperature can be stably reached without vibration.

In order to achieve the above object, the control method of the vehicle air conditioner according to the present invention comprises the steps of setting a target evaporator temperature; Calculating a temperature deviation between the target evaporator temperature and the actual evaporator temperature; Variablely setting a control coefficient according to the magnitude of the temperature deviation; Calculating a target control value of the pressure regulating valve of the variable displacement swash plate compressor using the control coefficient; And, controlling the pressure regulating valve.
In the setting of the target evaporator temperature, the user sets a target indoor temperature of the vehicle, detects and inputs the vehicle indoor temperature, the vehicle outdoor temperature, and the solar radiation amount from a sensor installed at a predetermined position of the vehicle, and the target indoor temperature and the vehicle. The target discharge temperature of the air conditioner vent is calculated according to the indoor temperature, the vehicle outdoor temperature, and the amount of insolation, the maximum evaporator temperature is input, and the target evaporator temperature is set by comparing the target discharge temperature of the vent with the maximum evaporator temperature. Characterized in that to be made.

According to the invention, the control coefficient is preferably proportional gain and integral gain. In addition, the control coefficient is preferably set to have a magnitude proportional to the absolute value of the temperature deviation. Further, the control coefficient is preferably set to the maximum set value when the absolute value of the temperature deviation is more than a predetermined value.

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The method may further include calculating a vent target discharge heat amount after detecting and inputting a vehicle indoor temperature, a vehicle outdoor temperature, and solar radiation amount from a sensor installed at a predetermined position of the vehicle.

The inputting of the maximum evaporator temperature is preferably performed to calculate and input the maximum evaporator temperature according to the air temperature introduced into the evaporator during the minimum driving of the compressor.

Further, in the step of comparing the target discharge temperature and the maximum evaporator temperature, if the target discharge temperature is lower than the maximum evaporator temperature, the target discharge temperature is set to the target evaporator temperature, and if the target discharge temperature is higher than the maximum evaporator temperature, the maximum evaporator temperature is set. It is desirable to set the target evaporator temperature.

The features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings. Prior to this, the terms or words used in the present specification and claims are based on the principle that the inventor can appropriately define the concept of terms in order to explain the invention in the best way. It should be interpreted as meanings and concepts corresponding to

1 shows an example of a variable displacement swash plate compressor 100.

As shown in FIG. 1, the compressor 100 includes: a cylinder block 110 having a plurality of cylinder bores 112 formed in a longitudinal direction along a concentric circle; A plurality of pistons (Piston, 114) inserted into each cylinder bore (112) of the cylinder block (110); A front housing 120 coupled to the front of the cylinder block 110 to form a crank chamber 122 therein; A rear housing 130 coupled to the rear of the cylinder block 110 to form a refrigerant suction chamber 132 and a refrigerant discharge chamber 134 therein; A drive shaft 140 supported over the front housing 120 and the cylinder block 110; A rotor (Rotor 142) rotating together with the drive shaft 140 in the crank chamber 122; A swash plate 144 which is installed to be movable around the drive shaft 140 and whose edge is coupled to each piston 114 so as to advance and retract the piston 114, and one side of which is hinged to the rotor 142; Interposed between the cylinder block 110 and the rear housing 130, the refrigerant is sucked into the cylinder bore 112 from the refrigerant suction chamber 132 and compressed into the refrigerant discharge chamber 134 from the cylinder bore 112. A valve unit 150 for discharging the refrigerant; In addition, the rear housing 130 is installed in the rear housing 130 to adjust the inclination angle of the swash plate 144 with respect to the drive shaft 140 by adjusting the opening degree of the refrigerant return flow path connecting the refrigerant discharge chamber 134 and the crank chamber 122. It includes an externally controlled pressure regulating valve (160).

According to the variable displacement swash plate compressor 100 as described above, by the rotation of the swash plate 144 a plurality of pistons 114 are sequentially moved forward and backward. At the time of retraction of the piston 114 from the cylinder bore 112 (that is, during the suction stroke), the suction side of the valve unit 150 is opened by the pressure drop inside the cylinder bore 112, and the cylinder bore 112 is opened. And the suction chamber communicate with each other, the refrigerant is sucked into the cylinder bore 112 from the suction chamber. When the piston 114 moves toward the cylinder bore 112 (that is, during the compression stroke), the refrigerant sucked into the cylinder bore 112 is compressed by an increase in the pressure inside the cylinder bore 112, thereby providing a valve unit. Since the discharge side of 150 is opened and the cylinder bore 112 and the refrigerant discharge chamber 134 communicate with each other, the compressed refrigerant is discharged from the cylinder bore 112 into the refrigerant discharge chamber 134. In addition, the inclination angle of the swash plate 144 is changed by adjusting the opening degree of the refrigerant return flow path connecting the refrigerant discharge chamber 134 and the crank chamber 122 by the pressure regulating valve 160 according to the load. The discharge capacity is varied. That is, as the swash plate 144 is inclined toward the drive shaft 140, the stroke distance of the piston 114 increases, and the discharge capacity of the refrigerant increases.

2 shows a vehicle air conditioner to which the variable displacement swash plate compressor 100 as described above is applied.

As shown in FIG. 2, the air conditioning apparatus includes an air conditioning case 210, a blower 220 installed at an inlet side of the air conditioning case 210, and an evaporator 200 embedded in the air conditioning case 210. ) And a heater core 230, a temperature control door 240 for adjusting an opening degree of a cold air passage and a warm air passage for air passing through the evaporator 200, and suctioning refrigerant from the evaporator 200. A variable capacity swash plate compressor 100 for discharging, a condenser 170 for condensing and discharging the refrigerant supplied from the compressor 100, and a receiver dryer for gas-liquid separation of the refrigerant supplied from the condenser 170 , 180, and an expansion valve 190 for throttling the refrigerant supplied from the receiver dryer 180 to the evaporator 200. Reference numerals 212, 214, and 216 denote vents, respectively, and reference numerals 212d, 214d, and 216d denote doors for adjusting the opening degrees of the vents 212, 214, and 216, respectively.

On the other hand, the drive output of the pressure regulating valve 160 for controlling the discharge capacity of the compressor 100 by adjusting the inclination angle of the swash plate 144 is controlled by the control unit 300. That is, the control unit 300 controls the output current value for the pressure regulating valve 160, and the opening degree of the refrigerant return flow path connecting the refrigerant discharge chamber 134 and the crank chamber 122 according to the control. By adjusting, the inclination angle of the swash plate 144 with respect to the drive shaft 140 is changed, the larger the inclination angle is to increase the discharge capacity of the compressor (100).

In FIG. 2, reference numeral 310 denotes various sensors such as an evaporator temperature sensor, an indoor temperature sensor, an outdoor temperature sensor, an insolation sensor, and the detection signal is input to the control unit 300.

Next, a control method of the vehicle air conditioner according to the present invention will be described.

As shown in FIG. 3, when the air conditioner is operated (S100), signals from various sensors 310 are input to the control unit 300 to the control unit 300 (S110).

When a signal is input to the control unit 300 from the sensors 310, a target evaporator temperature is set by the user (S120).

The target evaporator temperature can be set as follows. That is, as shown in Figure 5, the user sets the target room temperature (S121). Next, the vehicle indoor temperature, the vehicle outdoor temperature, and the amount of insolation are detected from the sensor 310 installed at the predetermined position of the vehicle and input to the control unit 300 (S122). Next, the target discharge temperature of the vents 212, 214, 216 of the air conditioner is calculated based on the target indoor temperature, the vehicle indoor temperature, the vehicle outdoor temperature, and the amount of insolation (S124). Next, the maximum evaporator temperature is input (S125). Next, the target discharge temperature of the vents 212, 214, and 216 is compared with the maximum evaporator temperature (S126) to select a target evaporator temperature (S127).

Here, the step of inputting the maximum evaporator temperature is preferably made to calculate and input the maximum evaporator temperature according to the air temperature flowing into the evaporator 200 during the minimum driving of the compressor 100.

Further, when setting the target evaporator temperature, in the step of comparing the target discharge temperature of the vent (212, 214, 216) and the maximum evaporator temperature, if the target discharge temperature is lower than the maximum evaporator temperature, the target discharge temperature is set to the target evaporator It is preferable to set the temperature and set the maximum evaporator temperature to the target evaporator temperature if the target discharge temperature is higher than the maximum evaporator temperature. That is, set the low temperature to the target evaporator temperature.

Further, after detecting and inputting the vehicle indoor temperature, the vehicle outdoor temperature, and the solar radiation amount from the sensors 310 installed at the predetermined positions of the vehicle (S122), the target discharge heat amount of the vents 212, 214, and 216 is calculated. In operation S123, the vent target discharge temperature may be calculated based on the target discharge heat amount of the vents 212, 214, and 216.

After the target evaporator temperature is set as described above, a temperature deviation between the target evaporator temperature and the actual evaporator temperature is calculated (S130).

The target evaporator temperature and the actual evaporator temperature mean an air temperature discharged through the evaporator or a temperature of the evaporator itself, and any one of them may be applied as necessary.

Next, the control coefficient is variably set according to the calculated magnitude of temperature deviation (S140).

The control coefficient is preferably a proportional gain and an integral gain.

In setting the control coefficient, when the temperature deviation is large, it is preferable that the control coefficient (ie, proportional gain, integral gain) is set large so as to quickly reach the target evaporator temperature. In addition, when the temperature deviation is small, it is preferable that the control coefficient is set small so that the target evaporator temperature can be stably reached without fluctuation.

An example of calculating the proportional gain is shown in the graph of FIG. 4A and an example of calculating the integral gain is shown in the graph of FIG. 4B, which is an example in which the proportional gain or the integral gain is set asymmetrically. In addition, as shown in FIG. 4C, the proportional gain or the integral gain may be set symmetrically. That is, the control coefficients may be set not only to have a single slope, but also may be set to be combined to have a plurality of slopes.

In setting the control coefficients as described above, if the temperature deviation becomes large in the '+' or '-' direction when the temperature deviation is '0', the proportional gain or the integral gain is increased in proportion to the temperature deviation. do. In other words, the control coefficient is set to have a magnitude proportional to the absolute value of the temperature deviation, and when the absolute value of the temperature deviation is more than a predetermined value, it is preferably set to the maximum setting value.

Next, the control value (ie, duty ratio (current value)) for the pressure regulating valve 160 of the variable displacement swash plate compressor 100 is variably calculated according to the calculated control coefficient, that is, the proportional gain and the integral gain. (S150). The control value can be obtained by the following equation.

Duty (n) = Duty (n-1)

        -Proportional control of Gp × {Evap_error (n) -Evap_error (n-1)}

        -Integral control of Gi × Evap_error (n)

Here, temperature deviation Evap_error (n) = Tevap_target-Tevap_now (n) can be obtained, Evap_error (n-1) = Tevap_target-Tevap_now (n-1), and Tevap_target is the target evaporator temperature, Tevap_now (n). Is the n-th actual evaporator temperature detected by the evaporator temperature sensor of the sensor 310, Tevap_now (n-1) is the n-th actual evaporator temperature detected by the evaporator temperature sensor of the sensor 310, Duty (n) Is the n-th pressure control valve 160 output, Gp is the proportional gain, Gi is the integral gain.

As described above, the pressure control valve 160 of the variable displacement swash plate compressor 100 is controlled by the calculated control value (S160). That is, proportional-integral control of the pressure regulating valve 160 until the actual evaporator temperature measured by the evaporator temperature sensor in the sensor 310 reaches the target evaporator temperature (S170).

According to the control method of the vehicle air conditioner according to the present invention configured as described above, in consideration of the temperature deviation between the target evaporator temperature and the actual evaporator temperature, the progress history of the evaporator temperature, and the nonlinear characteristics of the compressor and the air conditioning system By proportionally-integrating control of the pressure regulating valve 160 by an output value in which a variable and properly calculated proportional gain and integral gain are applied, the instability of the evaporator temperature and the system can be eliminated, and the convergence and response to the target evaporator temperature can be solved. Can improve the sex.

Claims (8)

Setting a target evaporator temperature; Calculating a temperature deviation between the target evaporator temperature and the actual evaporator temperature; Variablely setting a control coefficient according to the magnitude of the temperature deviation; Calculating a target control value of the pressure regulating valve of the variable displacement swash plate compressor using the control coefficient; And, And controlling the pressure regulating valve by using the target control value. In the setting of the target evaporator temperature, the user sets a target indoor temperature of the vehicle, detects and inputs the vehicle indoor temperature, the vehicle outdoor temperature, and the solar radiation amount from a sensor installed at a predetermined position of the vehicle, and the target indoor temperature and the vehicle. The target discharge temperature of the air conditioner vent is calculated according to the indoor temperature, the vehicle outdoor temperature, and the amount of insolation, the maximum evaporator temperature is input, and the target evaporator temperature is set by comparing the target discharge temperature of the vent with the maximum evaporator temperature. Control method of a vehicle air conditioning apparatus, characterized in that made to. The method of claim 1, And the control coefficient is a proportional gain and an integral gain. The method of claim 2, And the control coefficient is set to have a magnitude proportional to an absolute value of the temperature deviation. The method according to claim 2 or 3, And the control coefficient is set to a maximum set value when the absolute value of the temperature deviation is equal to or greater than a predetermined value. delete The method of claim 1, The step of inputting the maximum evaporator temperature, the control method of the vehicle air conditioner, characterized in that the input to calculate the maximum evaporator temperature in accordance with the air temperature flowing into the evaporator during the minimum driving of the compressor. The method of claim 1, In the step of comparing the target discharge temperature and the maximum evaporator temperature, if the target discharge temperature is lower than the maximum evaporator temperature, the target discharge temperature is set to the target evaporator temperature, and if the target discharge temperature is higher than the maximum evaporator temperature, the maximum evaporator temperature is the target evaporator Control method for a vehicle air conditioner, characterized in that the temperature setting. The method of claim 1, And calculating a vent target discharge heat amount after sensing and inputting a vehicle indoor temperature, a vehicle outdoor temperature, and an amount of solar radiation from a sensor installed at a predetermined position of the vehicle. .

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