KR100648943B1 - Refrigerator and control method thereof - Google Patents

Abstract

A refrigerator and a control method thereof are disclosed. The refrigerator and its control method according to the present invention smoothly flow the refrigerant to both the low pressure side evaporator and the high pressure side evaporator through effective control of the switching valve when switching the refrigerant flow path between two evaporators having different pressures. There is a purpose. The refrigerator according to the present invention includes a plurality of evaporators, a flow path switching device, and a control unit. The plurality of evaporators consists of a low pressure side evaporator and a high pressure side evaporator. The flow path switching device converts the flow path of the coolant between the low pressure side evaporator and the high pressure side evaporator, and simultaneously opens a section in which the coolant flow path is formed on both the low pressure side evaporator side and the high pressure side evaporator side while the flow path of the refrigerant is changed. The control unit controls the flow path switching device so that the simultaneous opening section when switching the refrigerant flow path from the low pressure side evaporator to the high pressure side evaporator lasts longer than the simultaneous opening section when switching the refrigerant flow path from the high pressure side evaporator to the low pressure side evaporator. To control.

Description

Refrigerator and its control method {REFRIGERATOR AND CONTROL METHOD THEREOF}

1 is a view showing a refrigerant cycle of a refrigerator according to an embodiment of the present invention.

2 is a timing chart showing a three-way valve control concept of a refrigerator according to an embodiment of the present invention.

Figure 3 is a block diagram showing a control system of the refrigerator according to the embodiment of the present invention.

Figure 4 is a flow chart showing a three-way valve control method for switching the refrigerant flow path from the refrigerator compartment evaporator to the freezer compartment evaporator in the refrigerator according to the embodiment of the present invention.

Figure 5 is a flow chart showing a three-way valve control method for switching the refrigerant flow path from the freezer compartment evaporator to the refrigerator compartment evaporator in the refrigerator according to an embodiment of the present invention.

* Description of the symbols for the main parts of the drawings *

201: Compressor

205: refrigerator compartment evaporator

207: Freezer Evaporator

210: refrigerator

220: freezer

302: condenser

304: refrigerator compartment capillary

308: freezer capillary

306: connecting capillary

The present invention relates to a refrigerator, and more particularly, to a refrigerator including a refrigerator compartment and a freezer compartment, each having an evaporator independent of each of the refrigerator compartment and the freezer compartment.

In general, the main body of the refrigerator is provided with a freezer compartment and a refrigerating compartment partitioned by an intermediate partition, and each of the freezer compartment and the refrigerating compartment is hinged to the main body is provided with a door for opening and closing the freezer compartment and the refrigerating compartment. An inner wall of the freezer compartment is provided with an evaporator and a fan for generating cold air and supplying it into the freezer compartment. There is also another evaporator and fan on the inner wall of the refrigerating compartment for generating cold air and supplying it into the refrigerating compartment. That is, cold air is independently supplied to the freezing compartment and the refrigerating compartment, which is called an independent cooling method.

The cooling of the refrigerating compartment and the freezing compartment independently is generally because the target cooling temperature required in the refrigerating compartment is relatively higher than the target cooling temperature required in the freezing compartment. In order to implement different cooling temperatures in the refrigerating compartment and the freezing compartment, the evaporation temperatures of the refrigerating compartment evaporator and the freezer compartment evaporator must be different, so that the degree of expansion (decompression) of the refrigerant at each front end of the evaporator must be different. To achieve this, a separate expansion device is placed at the front of each evaporator.

Independent cooling means that only one of the refrigerating compartment and the freezing compartment can be independently cooled. In order to independently cool only one of the refrigerating compartment and the freezing compartment, the refrigerant passage must be controlled to circulate the refrigerant to either the refrigerating compartment evaporator or the freezing compartment evaporator.

Different evaporation temperatures of the refrigerator compartment evaporator and the freezer compartment evaporator may be regarded as different pressures of the refrigerant of each evaporator. Due to the pressure difference of the refrigerant, the amount of the refrigerant is biased toward one of the evaporators, so that the flow of the refrigerant to the opposite evaporator is not smooth when the refrigerant flow path is switched.

The control method of the refrigerator according to the present invention to smoothly flow the refrigerant to both the low-pressure side evaporator and the high-pressure side evaporator through the effective control of the switching valve when switching the refrigerant flow path between the two evaporators having different pressures. There is this.

The refrigerator according to the present invention includes a plurality of evaporators, a flow path switching device, and a control unit. The plurality of evaporators consists of a low pressure side evaporator and a high pressure side evaporator. The flow path switching device converts the flow path of the coolant between the low pressure side evaporator and the high pressure side evaporator, and simultaneously opens a section in which the coolant flow path is formed on both the low pressure side evaporator side and the high pressure side evaporator side while the flow path of the refrigerant is changed. The control unit controls the flow path switching device so that the simultaneous opening section when switching the refrigerant flow path from the low pressure side evaporator to the high pressure side evaporator lasts longer than the simultaneous opening section when switching the refrigerant flow path from the high pressure side evaporator to the low pressure side evaporator. To control.

Further, the low pressure side evaporator is a freezer compartment evaporator for freezer compartment cooling, and the high pressure side evaporator is a refrigerator compartment evaporator for refrigerator compartment cooling.

In addition, the simultaneous opening section when switching the flow path of the refrigerant from the high pressure side evaporator to the low pressure side evaporator is a simultaneous opening section inevitably generated due to the limitation of the mechanical characteristics of the flow path switching device, and the refrigerant from the low pressure side evaporator toward the high pressure side evaporator. The simultaneous open section when switching flow paths is an open section intentionally occurring to last longer than the necessary simultaneous open section.

In addition, the flow path switching device is a three-way valve in which the refrigerant flow path is switched by the rotation of the stepping motor, and the limit of the mechanical characteristics of the flow path switching device is the limit of the rotational speed of the stepping motor.

The control method of the refrigerator according to the present invention includes a plurality of evaporators including a low pressure side evaporator and a high pressure side evaporator, and a low pressure side evaporator side while switching a refrigerant flow path between the low pressure side evaporator and a high pressure side evaporator. In a control method of a refrigerator including a flow path switching device in which a simultaneous opening section in which a refrigerant flow path is formed in both the high pressure side evaporator and the high pressure side evaporator, a simultaneous opening section when switching the flow path of the refrigerant toward the high pressure side evaporator The flow path switching device is controlled to last longer than the simultaneous opening section when switching the flow path of the refrigerant from the high pressure side evaporator to the low pressure side evaporator.

Further, the low pressure side evaporator is a freezer compartment evaporator for freezer compartment cooling, and the high pressure side evaporator is a refrigerator compartment evaporator for refrigerator compartment cooling.

In addition, the simultaneous opening section when switching the flow path of the refrigerant from the high pressure side evaporator to the low pressure side evaporator is a simultaneous opening section inevitably caused by the limitation of the mechanical characteristics of the flow path switching device. The simultaneous open section when switching flow paths is an open section intentionally occurring to last longer than the necessarily simultaneous open section.

In addition, the flow path switching device is a three-way valve in which the refrigerant flow path is switched by the rotation of the stepping motor, and the limit of the mechanical characteristics of the flow path switching device is the limit of the rotational speed of the stepping motor.

Still another refrigerator control method according to the present invention, the refrigerator expansion evaporator, the freezer compartment evaporator, the first expansion device for expanding the pressure of the refrigerant flowing into the refrigerator compartment evaporator to the first pressure, the pressure of the refrigerant flowing into the freezer compartment evaporator A second expansion device for inflating the pressure to a second pressure lower than the first pressure and a refrigerant flow path between the freezer compartment evaporator and the refrigerator compartment evaporator, wherein the refrigerant passage from the freezer evaporator to the refrigerator compartment evaporator is changed to the freezer compartment evaporator side and the refrigerator compartment evaporator. A control method of a refrigerator including a flow path switching device having a simultaneous opening section in which a refrigerant flow path is formed in both directions, wherein the flow path is maintained such that the simultaneous opening section is maintained for a predetermined time when the flow path of the refrigerant is changed from the freezer compartment evaporator to the refrigerator compartment evaporator. Control the switching device.

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When described with reference to Figures 1 to 4 a preferred embodiment of the present invention as follows. 1 is a view showing a refrigerant cycle of a refrigerator according to an embodiment of the present invention. As shown in FIG. 1, the refrigerant discharged from the compressor 201 passes through the three-way valve 310 so that the refrigerant discharged from the compressor 201 passes through the condenser 302 and flows into one of the refrigerating chamber capillary 304 and the freezing chamber capillary 308. do. When the refrigerator compartment valve 310a of the three-way valve 310 is closed and the freezer compartment valve 310b is opened, the refrigerant passing through the condenser 302 flows into the freezer compartment evaporator 207 through the freezer compartment capillary 308 to freezer compartment 220. ) Cooling alone. In contrast, in the refrigerating compartment cooling mode in which both the refrigerating compartment 210 and the freezing compartment 220 are cooled, the refrigerant passing through the condenser 302 by opening the refrigerating compartment valve 310a of the three-way valve 310 and closing the freezing compartment valve 310b. Through the refrigerating chamber capillary 304 and the connecting capillary tube 306 is introduced into the refrigerating chamber 210 and the freezing chamber 220 in turn.

The three-way valve 310 has a structure in which the refrigerant passage is switched by the rotation of the stepping motor (not shown). That is, the refrigerant passage is formed by at least one of the refrigerating chamber evaporator 205 and the freezing chamber evaporator 207 according to the rotation angle of the stepping motor. The switching of the refrigerant passage according to the rotation of the stepping motor will be described with reference to FIG. 2 as follows.

2 is a timing chart illustrating a three-way valve control concept of a refrigerator according to an embodiment of the present invention. As shown in FIG. 2, the refrigerating chamber valve 310a or the freezing chamber valve 310b is opened according to the rotation angle of the stepping motor to form a refrigerant passage. In FIG. 2, when the rotation angle of the stepping motor is 34 °, both the refrigerating chamber valve 310a and the freezing chamber valve 310b are closed, so that both the refrigerating chamber evaporator 205 and the freezing chamber evaporator 207 do not form a flow path of the refrigerant. As the stepping motor rotates further to reach 95 °, the refrigerating compartment valve 310a is still closed but the freezer compartment valve 310b is opened to form a refrigerant passage through the freezer compartment capillary 308 to the freezer compartment evaporator 207. When the stepping motor further rotates to reach 154 °, a simultaneous opening section is formed in which both the refrigerating chamber valve 310a and the freezing chamber valve 310b are opened. When the rotation angle of the stepping motor reaches about 195 °, the refrigerating compartment valve 310a is still open but the freezing compartment valve 310b is closed to form the refrigerant passage only through the refrigerating compartment capillary 304 to the refrigerating compartment evaporator 205. When the rotation angle of the stepping motor reaches 215 °, both the refrigerating chamber valve 310a and the freezing chamber valve 310b are closed, so that the refrigerant passage is not formed in either the refrigerating chamber capillary 304 or the freezing chamber capillary 308.

As such, the refrigerant passage is determined by the rotation of the stepping motor for driving the opening and closing of the three-way valve 310. The section in which both the refrigerating chamber valve 310a and the freezing chamber valve 310b are opened as in the vicinity of 154 ° of FIG. 2. (t0) is present. In this section t0, refrigerant may flow to both the refrigerator compartment evaporator 205 and the freezer compartment evaporator 207, but in practice this is because the pressure of the refrigerator compartment evaporator 207 is relatively lower than that of the refrigerator compartment evaporator 205. In the section t0, the refrigerant flows more toward the refrigerator compartment evaporator 205 than the freezer compartment evaporator 207. For this reason, when switching from the freezer cooling mode to the freezing chamber cooling mode (that is, when the stepping motor is rotated to 95 ° through 154 ° and 195 °), the refrigerant flowing toward the freezer evaporator 207 is momentarily. Since it flows toward the refrigerating chamber evaporator 205, it is impossible to supply a sufficient amount of refrigerant to the freezing chamber evaporator 207. Because the freezer compartment evaporator 207 has a lower pressure than the freezer compartment evaporator 205, the refrigerant present in the refrigerator compartment evaporator 205 flows into the freezer compartment evaporator 207 and the refrigerant is stored in the refrigerator compartment evaporator 205. There is almost no remaining. In order to solve this problem, when switching from the freezer cooling mode to the freezer cooling mode, that is, when the stepping motor is switched to 195 ° through a 154 ° section with a rotation angle of 95 °, the refrigerator compartment valve 310a and the freezer compartment By maintaining a relatively long (about 10 seconds) 154 ° section t0 in which the valve 310b is fully opened, the refrigerant flows to both the refrigerating chamber evaporator 205 and the freezing chamber evaporator 207 simultaneously for a predetermined time, thereby freezing chamber evaporator 207 The refrigerant flow is not blocked, so that the refrigerant can be supplied sufficiently smoothly through the flow path toward the freezer compartment evaporator 207.

For such control, the refrigerator according to the embodiment of the present invention has a control system as shown in FIG. 3. 3 is a block diagram illustrating a control system of a refrigerator according to an embodiment of the present invention. As shown in FIG. 3, an input unit 354 and a temperature detector 356 are connected to an input terminal of the control unit 352 that controls the overall operation of the refrigerator. The input unit 354 allows a user to set a desired target cooling temperature, a cooling mode, or the like, and the temperature detector 356 may include the internal temperature of each of the refrigerator compartment 210 and the freezer compartment 220, the refrigerator compartment evaporator 205, and The evaporation temperature of each freezer compartment evaporator 207 is detected and provided to the controller 352. The controller 352 controls the overall cooling operation of the refrigerator based on the temperature of each part detected by the temperature detector 356. The compressor 201 and the 3-way valve 310 are connected to an output end of the controller 352 and controlled by the controller 352 to implement a cooling mode and a target cooling temperature set by a user. The control operation of the controller 352 will now be described with reference to FIGS. 4 and 5.

4 is a flowchart illustrating a three-way valve control method for switching a refrigerant passage from a refrigerating chamber evaporator to a freezing chamber evaporator in a refrigerator according to an exemplary embodiment of the present invention. As shown in FIG. 4, when the rotation angle of the stepping motor of the three-way valve 310 is 195 °, the refrigerating chamber valve 310a is opened and the freezing chamber valve 310b is closed to close the refrigerating chamber 210 and the freezing chamber 220. This is followed by a cold room cooling mode in which all are cooled (402). When the inside temperature of the refrigerating compartment 210 reaches the target temperature and the cooling of the refrigerating compartment 210 is completed, the controller 352 checks whether the inside temperature of the freezing compartment 220 has reached the target temperature to further cool only the freezing compartment 220. It is determined whether it is necessary to determine whether to switch the flow path of the refrigerant from the refrigerating chamber 210 to the freezing chamber 220 in order to perform the freezing chamber alone cooling mode (404). When the flow path of the refrigerant is switched from the refrigerating chamber 210 to the freezing chamber 220, the controller 352 converts the rotation angle of the stepping motor from 195 ° to 154 ° (406). This is an intermediate process for the stepping motor to rotate to 95 °, and is a simultaneous open state in which both the refrigerating chamber valve 310a and the freezing chamber valve 310b are opened. In the case of switching the flow path from the refrigerating chamber 210 to the freezing chamber 220, the stepping motor is immediately rotated to 95 ° in this simultaneous open state to close the refrigerating chamber valve 310a and freezer valve 310b without additional intentional additional delay. By opening only the freezing chamber 220 is performed to cool only the freezer compartment 220 is performed (408). The simultaneous opening section of the refrigerating chamber valve 310a and the freezing chamber valve 310b at this time is limited to the minimum section inevitably generated by the rotational speed of the stepping motor (for example, 3 seconds). However, if the rotational speed of the stepping motor is very fast, this simultaneous opening section may hardly exist. As such, when the flow path is changed from the refrigerating chamber 210 to the freezing chamber 220, the time at which both the valves 310a and 310b are opened is minimized so that the refrigerant in the refrigerating chamber evaporator 205 is concentrated toward the freezing chamber evaporator 207. Can be reduced.

5 is a flowchart illustrating a three-way valve control method for switching a refrigerant passage from a freezer compartment evaporator to a refrigerator compartment evaporator in a refrigerator according to an exemplary embodiment of the present invention. As shown in FIG. 5, in the state where the stepping motor of the three-way valve 310 is 95 °, all of the freezer compartments in which the refrigerating compartment valve 310a is closed and the freezer compartment valve 310b are opened to freeze the refrigerating compartment 220 alone are all cooled. Is performed (502). When the internal temperature of the freezer compartment 220 reaches the target temperature and the sole cooling of the freezer compartment 220 is completed, it is determined whether the refrigerator compartment 210 needs to be cooled and the refrigerator compartment 210 is operated in the freezer compartment 220 to perform the refrigerator compartment cooling mode. In operation 504, it is determined whether to switch the flow path. When the flow path is switched from the freezer compartment 220 to the refrigerating compartment 210, the rotation angle of the stepping motor is changed from 95 ° to 154 ° (506). This is an intermediate process for the stepping motor to rotate to 195 °, and is a simultaneous open state in which both the refrigerating chamber valve 310a and the freezing chamber valve 310b are opened. In the embodiment of the present invention, when the flow path is switched from the freezer compartment 220 to the refrigerating compartment 210, both valves 310a and 310b are opened for a predetermined time (for example, 10 seconds) predetermined in this intermediate process. The concurrent open state is maintained (508). As such, when the flow path is changed from the freezer compartment 220 to the refrigerating compartment 210, the refrigerants already supplied to the freezer compartment evaporator 207 by opening both valves 310a and 310b for a predetermined time (for example, 10 seconds). The state of the liquid from the liquid phase to the gas phase is sufficiently made so that the liquid refrigerant does not flow into the compressor 201. This predetermined intended simultaneous opening section (e.g. 10 seconds) is stepped when the refrigerant flow path is switched from the refrigerator compartment evaporator 210 to the freezer compartment evaporator 220 (i.e. when the stepping motor rotates from 195 ° to 95 °). It is preferable to delay the coolant supply cutoff time to the freezer compartment evaporator 207 by setting a longer time than the simultaneous opening section (for example, 3 seconds) which is inevitably generated by the mechanical characteristics of the motor and the 3-way valve 310. After the set time (10 seconds) has elapsed, the stepping motor is rotated to 195 ° to close the freezer compartment valve 310b and open only the refrigerating compartment valve 310a to cool the refrigerating compartment 210 and the freezer compartment 220 in order. Perform the mode (510).

In the present invention as described above, the flow path switching device may use not only a valve employing a stepping motor but also a valve employing a solenoid.

The control method of the refrigerator according to the present invention is a refrigerant from the low pressure side evaporator to the high pressure side evaporator through the effective control of the flow path switching valve when switching the refrigerant flow path between the two evaporators having different pressures. By gradually reducing the supply and by gradually increasing the supply of refrigerant to the high pressure side evaporator, the phase change of the refrigerant from the low pressure side evaporator (liquid to gas phase) is insufficient when the supply of refrigerant to the low pressure side evaporator is suddenly shut off. Liquid refrigerant can be prevented from flowing into the compressor as it is.

Claims (10)

A plurality of evaporators comprising a low pressure side evaporator and a high pressure side evaporator; The flow path switching is performed between the low pressure side evaporator and the high pressure side evaporator, and the flow path is simultaneously generated in which a coolant flow path is formed in both the low pressure side evaporator and the high pressure side evaporator while the flow path of the refrigerant is switched. An apparatus; The flow path such that the simultaneous opening section when switching the flow path of the refrigerant toward the high pressure side evaporator from the low pressure side evaporator lasts longer than the simultaneous opening section when switching the flow path of the refrigerant toward the low pressure side evaporator from the high pressure side evaporator; Refrigerator including a control unit for controlling the switching device. The method of claim 1, The low pressure side evaporator is a freezer compartment evaporator for freezer compartment cooling; The high pressure side evaporator is a refrigerator compartment evaporator for refrigerating compartment cooling. The method of claim 1, The simultaneous opening section when switching the flow path of the refrigerant from the high pressure side evaporator toward the low pressure side evaporator is a simultaneous opening section inevitably generated by the limitation of the mechanical characteristics of the flow path switching device; And the simultaneous opening section when switching the flow path of the refrigerant from the low pressure side evaporator toward the high pressure side evaporator is an opening section intentionally occurring to last longer than the necessary simultaneous opening section. The method of claim 3, wherein The flow path switching device is a three-way valve in which the refrigerant flow path is switched by rotation of a stepping motor; The limit of the mechanical characteristics of the flow path switching device is a limit of the rotational speed of the stepping motor. A plurality of evaporators comprising a low pressure side evaporator and a high pressure side evaporator, and the low pressure side evaporator side and the high pressure side evaporator side while switching the flow path of the refrigerant between the low pressure side evaporator and the high pressure side evaporator In the control method of the refrigerator including a flow path switching device which generates a simultaneous opening section in which all of the refrigerant flow path is formed, The flow path such that the simultaneous opening section when switching the flow path of the refrigerant toward the high pressure side evaporator from the low pressure side evaporator lasts longer than the simultaneous opening section when switching the flow path of the refrigerant toward the low pressure side evaporator from the high pressure side evaporator; Control method of the refrigerator to control the switching device. The method of claim 5, The low pressure side evaporator is a freezer compartment evaporator for freezer compartment cooling; The high pressure side evaporator is a refrigerator compartment evaporator for cooling a refrigerator compartment. The method of claim 5, The simultaneous opening section when switching the flow path of the refrigerant from the high pressure side evaporator toward the low pressure side evaporator is a simultaneous opening section inevitably generated by the limitation of the mechanical characteristics of the flow path switching device; And the simultaneous opening section when switching the flow path of the refrigerant from the low pressure side evaporator toward the high pressure side evaporator is an opening section intentionally occurring to last longer than the necessary simultaneous opening section. The method of claim 7, wherein The flow path switching device is a three-way valve in which the refrigerant flow path is switched by rotation of a stepping motor; The limit of the mechanical characteristics of the flow path switching device is a limit of the rotational speed of the stepping motor control method of the refrigerator. delete A first expansion device for expanding a pressure of a refrigerator compartment evaporator, a freezer compartment evaporator, and a refrigerant flowing into the refrigerator compartment evaporator to a first pressure, and a second pressure lowering a pressure of the refrigerant flowing into the freezer compartment evaporator than the first pressure; A second expansion device for inflating the air and the refrigerant path between the freezer compartment evaporator and the refrigerating chamber evaporator, wherein the refrigerant flows toward both the freezer compartment evaporator and the refrigerator compartment evaporator when the refrigerant passage is switched from the freezer compartment evaporator to the refrigerator compartment evaporator. In the control method of the refrigerator comprising a flow path switching device that generates a simultaneous opening section in which a flow path is formed, And controlling the flow path switching device such that the simultaneous opening section is maintained for a preset time when the flow path of the refrigerant is switched from the freezer compartment evaporator to the refrigerating compartment evaporator.

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