JP2023125463A - refrigerator - Google Patents

Abstract

To provide a refrigerator capable of performing appropriate temperature control with respect to a temperature change affecting freshness of food.SOLUTION: A refrigerator comprises a casing, a cooling section and a control section. The casing has a storage section. The cooling section cools the storage section. The control section: executes ice crystallization control which alternately repeats low temperature cooling control to cool the storage section at a first temperature range and high temperature cooling control to cool the storage section at a second temperature range, higher than the first temperature range; suspends the ice crystallization control when detecting that a door on the casing is opened and closed while the ice crystallization control is in execution; determines damage to food in the storage section on the basis of a determination temperature which is a temperature after the lapse of predetermined time since detecting that the door is opened and closed; and controls a temperature of the storage section on the basis of the determination.SELECTED DRAWING: Figure 1

Description

Embodiments of the present invention relate to a refrigerator.

2. Description of the Related Art Refrigerators are known in which a small freezer compartment is provided in the freezer compartment and configured as a switching compartment that can adjust the temperature. By storing food in a small freezer compartment by adjusting the temperature appropriately, an ice film is formed on the surface of the food and the food can be kept fresh for a long time.

Japanese Patent Application Publication No. 2013-19559

The problem to be solved by the present invention is to provide a refrigerator that can perform appropriate temperature control against temperature changes that affect the freshness of food.

The refrigerator of the embodiment includes a housing, a cooling section, and a control section. The housing includes a reservoir. A cooling section cools the storage section. A control section controls the temperature of the storage section. The control unit is configured to control ice crystals, which alternately repeats low-temperature cooling control in which the storage unit is cooled in a first temperature zone, and high-temperature cooling control in which the storage unit is cooled in a second temperature zone higher than the first temperature zone. When the ice crystal control is executed and the opening/closing of a door provided in the casing is detected during the execution of the ice crystal control, the ice crystal control is interrupted and a predetermined period of time has elapsed since the opening/closing of the door was detected. Damage to the ice film on the surface of the food in the storage section is determined based on the determination temperature, which is the temperature after the temperature, and the temperature of the storage section is controlled based on the determination.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal side view showing the overall schematic configuration of a refrigerator according to an embodiment. FIG. 1 is a front view showing a refrigerator according to an embodiment. FIG. 1 is a configuration diagram of a refrigeration cycle device according to an embodiment. FIG. 2 is a block diagram showing a control unit of the refrigerator according to the embodiment. FIG. 3 is a diagram showing changes in set temperature when performing switching chamber ice crystal control according to the embodiment. 5 is a flowchart showing the flow of control when opening and closing a door in the first embodiment. 1 is a flowchart illustrating an example of a method for determining the state of an ice film according to the first embodiment. 5 is a flowchart showing an example of temperature control when a door is opened and closed during high-temperature cooling control according to the first embodiment. FIG. 3 is a diagram illustrating the maintenance time of the first embodiment. 2 is a flowchart showing an example of temperature control when a door is opened and closed during low-temperature cooling control according to the first embodiment. The first diagram showing an example of temperature control according to the first embodiment. The 2nd figure showing an example of temperature control of a 1st embodiment. The figure which shows an example of the execution timing of defrosting operation, high temperature cooling control, and low temperature cooling control. The figure which shows an example of the execution timing of defrosting operation, high temperature cooling control, and low temperature cooling control of 2nd Embodiment. The figure which shows an example of the execution timing of refrigeration operation, freezing operation, high temperature cooling control, and low temperature cooling control. The figure which shows an example of the execution timing of the refrigeration operation, freezing operation, high temperature cooling control, and low temperature cooling control of 3rd Embodiment. FIG. 3 is a diagram showing the occurrence of target temperature overshoot in high temperature cooling control during refrigeration operation and target temperature undershoot in low temperature cooling control during refrigeration operation. FIG. 7 is a diagram illustrating control for suppressing overshoot and undershoot according to the fourth embodiment.

Hereinafter, a refrigerator according to an embodiment will be described with reference to the drawings. In the following description, components having the same or similar functions are denoted by the same reference numerals. Further, redundant explanations of these configurations may be omitted. In this specification, left and right are defined based on the direction in which the refrigerator is viewed from a user standing in front of the refrigerator. Furthermore, when viewed from the refrigerator, the side closest to the user standing in front of the refrigerator is defined as the "front", and the side far away from the user is defined as the "back".

Hereinafter, a refrigerator according to an embodiment will be described with reference to the drawings. In the following description, components having the same or similar functions are denoted by the same reference numerals. Further, redundant explanations of these configurations may be omitted. "Based on XX" means "based on at least XX" and may include cases where it is based on another element in addition to XX. "Based on XX" is not limited to cases in which XX is used directly, but may also include cases in which calculations and processing have been performed on XX. "XX or YY" is not limited to either XX or YY, but may include both XX and YY. "XX" and "YY" are arbitrary elements (for example, arbitrary information).

<Embodiment>
(Refrigerator configuration)
FIG. 1 is a longitudinal sectional side view showing the overall schematic configuration of a refrigerator 1 according to an embodiment. FIG. 2 is a front view showing the refrigerator 1 of the embodiment. The refrigerator 1 is configured by providing a plurality of storage chambers within a vertically long rectangular box-shaped insulating casing 2 with an open front. Specifically, inside the heat-insulating case 2, a refrigerator compartment 3 and a vegetable compartment 4 are provided in order from the top, and below that, an ice-making compartment 5 (see FIG. 2) and a small freezer compartment 6 are provided side by side. , a freezing chamber 7 is provided below these. The heat-insulating casing 2 is an example of a "casing".

The refrigerator compartment 3 and the vegetable compartment 4 are both storage compartments in a refrigeration temperature range (for example, a positive temperature range of 1 to 4°C). A hinged heat insulating door 3a is provided at the front of the refrigerator compartment 3, and a pull-out heat insulating door 4a is provided at the front of the vegetable compartment 4. A case 4b constituting a storage container is provided on the back side of the heat insulating door 4a.

A chilled compartment 10 is provided at the lowest part of the refrigerator compartment 3 (above the partition wall 9). The chilled chamber 10 stores foods such as fermented foods such as yogurt and fresh cream, fresh foods, pasted products, and dairy products at a temperature as low as possible without freezing, for example, at a temperature of 1°C. Note that the chilled chamber 10 may store food at -3° C. (partial) in the slight freezing range.

The ice making compartment 5, the small freezing compartment 6, and the freezing compartment 7 are all storage compartments in the freezing temperature range (for example, a minus temperature range of -10 to -20°C). The freezer compartment 6 is vertically partitioned by a heat insulating partition wall 8. As shown in FIG. 1, the front part of the small freezer compartment 6 is provided with a pull-out heat insulating door 6a to which a storage container 6b is connected. A pull-out heat insulating door 5a is also provided at the front of the ice making compartment 5. The front part of the freezer compartment 7 is also provided with a pull-out heat insulating door 7a to which a lower storage container 7b and an upper storage container 7c are connected. The small freezer compartment 6 is an example of a "storage section."

A refrigeration cycle device 16 (see FIG. 3) is incorporated in the refrigerator 1 to cool each storage compartment. Although the details will be described later, the refrigeration cycle device 16 includes a refrigeration cooler 11 for cooling the storage compartments in the refrigerated temperature range (refrigeration compartment 3, chilled compartment 10, vegetable compartment 4), and storage compartments in the freezing temperature range ( It is configured to include a freezing cooler 12 for cooling an ice making compartment 5, a small freezing compartment 6, and a freezing compartment 7).

On the back wall of the storage compartments (refrigerated compartment 3, chilled compartment 10, vegetable compartment 4) in the refrigerated temperature range of the refrigerator 1,
A cold storage cooler compartment 32, a cold air supply duct 30 for supplying cold air generated by the refrigerator cooler 11 into the refrigerator compartment 3 (and vegetable compartment 4), and the like are provided. The refrigeration cooler 11 and the refrigeration fan 13 are arranged in the refrigeration cooler chamber 32 . A refrigerating fan 13 is disposed above the refrigerating cooler 11. The refrigeration fan 13 is an example of a blower, and sends air cooled by the refrigeration cooler 11. The upper end of the refrigerating cooler chamber 32 is connected to the lower end of a cold air supply duct 30 that is provided so as to extend upwardly on the back wall of the refrigerating chamber 3 with a constant width. The cold air supply duct 30 is provided with a plurality of refrigerating cold air supply ports 30a that open in the refrigerator compartment 3 and a chilled cold air supply port 30b that opens in the chilled compartment. In this configuration, when the refrigerating fan 13 is driven, the air in the vegetable compartment 4 is sucked into the refrigerating cooler 11 through the suction ports 13a and 13b, mainly as shown by the arrows in FIG. The sucked air is sent by the refrigeration blower fan 13, passes through the cold air supply duct 30, is blown into the refrigerator compartment 3 from the plurality of refrigeration cold air supply ports 30a, and is blown into the chilled compartment 10 from the chilled cold air supply port 30b. It's blown out. The air blown into the refrigerator compartment 3 flows from the refrigerator compartment 3 to the vegetable compartment 4, and the air blown into the chilled compartment 10 flows from the chilled compartment 10 to the vegetable compartment 4, and is finally used as a cooling air blower. A circulation is performed in which the air is sucked into the fan 13.

A freezing cooler chamber 33 is provided on the back wall of the storage compartments (ice making compartment 5, small freezing compartment 6, freezing compartment 7) in the freezing temperature range of the refrigerator 1. At the lower part of the freezing cooler chamber 33, the freezing cooler 12, the defrosting heater 15, and the like are arranged. The defrosting heater 15 is heated during a defrosting operation for the freezing cooler 12 and removes frost from the freezing cooler 12 . Furthermore, a freezing fan 14 is disposed above the freezing cooler chamber 33. The freezing fan 14 is an example of a blower, and sends air cooled by the freezing cooler 12. A cold air outlet 33a is provided at the front surface of the freezing cooler chamber 33, and a return port 33b is provided at the lower end. In this configuration, when the freezing fan 14 is driven, the cold air generated by the freezing cooler 12 is supplied from the cold air outlet 33a into the ice making compartment 5, the small freezing compartment 6, and the freezing compartment 7. , and is returned to the refrigeration cooler chamber 33 through the return port 33b. Thereby, the ice making compartment 5, the small freezing compartment 6, and the freezing compartment 7 are cooled. Among the plurality of cold air outlets 33a and return ports 33b, a damper 34a and a damper 34b are provided in the cold air outlet 33a1 to the small freezer compartment 6 and the return port 33b1 from the small freezer compartment 6, respectively, so as to be openable and closable. There is. That is, when the dampers 34a and 34b are closed, the supply of cold air to the small freezer compartment 6 is stopped, and when the dampers 34a and 34b are opened, the cold air is supplied to the small freezer compartment 6. Furthermore, a bottom heater 35 is installed on the bottom of the storage container 6b. The temperature of the small freezing compartment 6 can be adjusted independently of the ice making compartment 5 and the freezing compartment 7 by opening and closing the dampers 34a and 34b and heating and stopping the bottom heater 35. A switch 36 is provided near the opening of the small freezer compartment 6 to detect opening/closing of the pull-out heat insulating door 6a. Further, in the vicinity of the damper 34a in the small freezing compartment 6, a small freezing compartment temperature sensor 37 for detecting the temperature of the small freezing compartment 6 is provided. With this configuration, the small freezer compartment 6 can be treated as a switching room (a room that can be switched for multiple purposes) whose temperature can be adjusted independently from the surroundings.

As shown in FIG. 1, a machine compartment 40 is provided on the back side of the lower end of the refrigerator 1. As shown in FIG. In the machine room 40, a compressor 20 and a condenser 21 (see FIG. 3) that constitute the refrigeration cycle device 16, a cooling fan (not shown) for cooling these, and the like are arranged. As shown in FIG. 1 , a control section 100 made up of a computer such as a microcomputer is provided at the top of the refrigerator 1 , and the control section 100 controls the entire refrigerator 1 . The control unit 100 will be described later.

Next, the configuration of the refrigeration cycle device 16 will be described in detail. FIG. 3 is a configuration diagram of the refrigeration cycle device 16 of the embodiment. As shown in the figure, the refrigeration cycle device 16 includes a compressor 20, a condenser 21, a dryer 22, a three-way valve 23, capillary tubes 24, 25, and coolers 11, 12 in the order of flow of refrigerant. It is connected to the. A condenser 21 and a dryer 22 are sequentially connected to a high-pressure discharge port of the compressor 20 via a connecting pipe 26 . A three-way valve 23 is connected to the discharge side of the dryer 22. The three-way valve 23 has one inlet to which the dryer 22 is connected and two outlets. One of the two outlets of the three-way valve 23 is connected to the refrigeration side capillary tube 24 and the refrigeration cooler 11 in this order. The refrigeration cooler 11 is connected to the compressor 20 via a refrigeration side suction pipe 27 that is a connection pipe.

The freezing side capillary tube 25 and the freezing cooler 12 are connected in this order to the other of the two outlets of the three-way valve 23 . The refrigeration cooler 12 is connected to the compressor 20 via a refrigeration side suction pipe 28 which is a connecting pipe. Note that a check valve 29 is provided between the freezing cooler 12 and the suction pipe 28 to prevent the refrigerant from the refrigeration cooler 11 from flowing back to the freezing cooler 12 side.

Next, the flow of refrigerant in the refrigeration cycle device 16 will be explained. First, the refrigerant circulating through the refrigeration cycle device 16 is compressed by the compressor 20 to become a high-temperature, high-pressure gaseous refrigerant. This gaseous refrigerant is heat-radiated by the condenser 21 and becomes a medium-temperature, high-pressure liquid refrigerant. Thereafter, the liquid refrigerant from which impurities such as dirt and moisture have been removed passes through the dryer 22 and enters the refrigeration side capillary tube 24 (or the freezing side capillary tube 25) while being controlled by the three-way valve 23. At this time, the medium temperature, high pressure liquid refrigerant in the refrigeration side capillary tube 24 (or freezing side capillary tube 25) is depressurized while exchanging heat with the refrigerant in the refrigeration side suction pipe 27 (or freezing side suction pipe 28). . Then, this refrigerant evaporates while passing through the refrigerating cooler 11 (or the freezing cooler 12), and the inside of the refrigerating cooler chamber 32 (or the freezing cooler chamber 33) is cooled. Thereafter, the refrigerant, which has become a gas at low temperature and low pressure, flows into the refrigeration side suction pipe 27 (or the freezing side suction pipe 28). At this time, the temperature of the refrigerant gas immediately after flowing into the refrigeration side suction pipe 27 (or refrigeration side suction pipe 28) from the refrigeration cooler 11 (or the refrigeration cooler 12) is as low as about -10°C. However, while passing through the suction pipe 27 (or suction pipe 28), this refrigerant gas exchanges heat with the refrigerant in the capillary tube 24 (or capillary tube 25), and the temperature eventually rises to about room temperature. be done. This refrigerant gas is then sucked into the compressor 20 again, completing the circulation of the refrigerant.

In the refrigeration cycle device 16 described above, the three-way valve 23 is controlled by the control unit 100 (see FIG. 4), and selects one or both of the flow path B and the flow path C. Flow path B is a flow path for cooling the storage compartments in the refrigerated temperature range (refrigeration compartment 3, chilled compartment 10, vegetable compartment 4), while flow path C is used for cooling the storage compartments in the freezing temperature range (ice making compartment 5). , small freezer compartment 6, and freezer compartment 7). These two flow paths merge at a junction D, and the refrigerant flows from this junction D in the direction of arrow E and returns to the compressor 20.

If flow path B is selected by switching the refrigerant flow path as described above, a refrigeration operation is performed to cool the storage compartments (refrigerated compartment 3, chilled compartment 10, vegetable compartment 4) in the refrigeration temperature range, and the flow If path C is selected, a freezing operation will be performed to cool the storage compartments in the freezing temperature range (ice making compartment 5, small freezer compartment 6, freezing compartment 7), and if both channels B and C are selected, , performs both refrigeration and freezing operations. Moreover, by heating the defrosting heater 15, the frost attached to the freezing cooler 12 can be melted and evaporated (defrosting operation).
In this embodiment, the compressor 20, the refrigeration cooler 11, the refrigeration blower fan 13, the refrigeration cooler 12, and the refrigeration blower fan 14 constitute an example of a "cooling section."

FIG. 4 is a block diagram showing the control unit 100 of the refrigerator 1 according to the embodiment. The control unit 100 is composed of a computer having a microcomputer, a timer 101, etc., and controls the refrigerator 1 in general. The switch 36, the refrigeration cycle device 16, the small freezer temperature sensor 37, the damper 34a, the damper 34b, the refrigeration blower fan 14, the bottom heater 35, the defrosting heater 15, and the storage unit 116 are each connected to the control unit 100. , are each driven and controlled by commands from the control unit 100. The storage unit 116 stores information necessary for operating the refrigerator 1. For example, the storage unit 116 stores, for example, threshold values and functional formulas, which will be described later. The cooling fan 14 is an example of a "blower". The bottom heater 35 is an example of a "heating device". The damper 34a and the damper 34b constitute an example of a "switching device". The control unit 100 is an example of a “control unit”.

The control unit 100 executes "refrigerating operation" and "freezing operation" as basic operations of the refrigerator 1. “Refrigerating operation” is an operation in which the three-way valve 23 is switched and liquid refrigerant is supplied from the compressor 20 to the refrigeration cooler 11. "Freezing operation" is an operation in which the three-way valve 23 is switched and liquid refrigerant is supplied from the compressor 20 to the freezing cooler 12. For example, the control unit 100 alternately performs the refrigeration operation and the freezing operation, so that the storage compartments in the refrigeration temperature range (refrigeration compartment 3, chilled compartment 10, vegetable compartment 4) and the storage compartments in the freezing temperature range (ice making compartment) 5. The refrigeration cycle device 16 is controlled so that the small freezer compartment 6 and the freezer compartment 7) are maintained within their respective set temperature ranges. While the refrigeration operation is performed, the temperature of the storage compartment in the refrigerating temperature range decreases, but the temperature of the storage compartment in the freezing temperature range increases. On the other hand, while the freezing operation is performed, the temperature in the storage compartment in the freezing temperature range decreases, but the temperature in the storage compartment in the refrigeration temperature range increases. Therefore, the temperature of the storage chamber in the refrigeration temperature zone and the temperature in the storage chamber in the freezing temperature zone repeatedly rise and fall in a sawtooth pattern.

Further, in the small freezing compartment 6, the control unit 100 controls the inside of the small freezing compartment 6 to a so-called partial target temperature (for example, -1°C to -3°C), which is a temperature in a semi-frozen/slightly frozen state. ) "switchable chamber ice crystal control" can be executed to cool the room to a certain temperature. As a result, the inside of the small freezer compartment 6 is maintained in a partial temperature range corresponding to the partial target temperature. In the "switching chamber ice crystal control", as shown in FIG. After that, high-temperature cooling control is performed to cool the small freezing compartment 6 in a second temperature zone higher than the first temperature zone for a predetermined second time (for example, 5 hours), and then, the small freezing is performed for the first hour. The temperature of the small freezer compartment 6 is controlled using a cooling pattern that includes performing low-temperature cooling control to cool the compartment 6 in a first temperature range. The center temperature of the first temperature zone is, for example, -5°C. Hereinafter, the center temperature of the first temperature zone may be referred to as a low-temperature target temperature. The first temperature range is a temperature at which the surface of the stored items in the small freezer compartment 6 is slightly frozen. The first temperature zone is a temperature zone in which the stored items in the small freezer compartment 6 do not freeze to the middle, but can form a layer of ice only on the surface. The center temperature of the second temperature zone is, for example, 1°C. Hereinafter, the center temperature of the second temperature zone may be referred to as a low-temperature target temperature. The second temperature zone is the temperature at which the slightly frozen layer formed on the surface of the storage material can be thawed. When executing the "switchable compartment ice crystal control", the control unit 100 controls the refrigeration cycle device 16 to set the storage compartments (ice making compartment 5, freezing compartment 7) in the freezing temperature range to a set temperature (for example, -18°C). ), the bottom heater 35 is heated to control the temperature inside the small freezer compartment 6 from the first temperature zone to the second temperature zone. Specifically, when moving from low-temperature cooling control to high-temperature cooling control, the bottom heater 35 is used to raise the temperature with the dampers 34a and 34b closed, and when moving from high-temperature cooling control to low-temperature cooling control, the dampers 34a and 34b are closed. 34b is opened to lower the temperature. When converging and maintaining the temperature of the small freezer compartment 6 in each of the high-temperature cooling control and the low-temperature cooling control, the control unit 100 sets a target temperature for the bottom heater 35 with the dampers 34a and 34b closed, and The heater 35 is controlled by PID (Proportional Integral Differential). Switching chamber ice crystal control is an example of "ice crystal control."

(First embodiment)
When the insulation doors 5a, 6a, and 7a of the storage compartments in the freezing temperature range (ice making compartment 5, small freezing compartment 6, and freezing compartment 7) are opened or closed, or when the number of items stored in the small freezing compartment 6 increases, the temperature of the small freezing compartment changes. The temperature inside the small freezer compartment 6 detected by the sensor 37 rises to a predetermined temperature or higher. When the temperature of the small freezer compartment 6 increases, the ice film on the surface of the food may disappear or its formation may be inhibited. On the other hand, if excessive cooling is performed after opening and closing the heat insulating doors 5a, 6a, and 7a, there is a possibility that not only the surface of the food but also the contents thereof will freeze. In either case, the freshness of the food will be impaired.

Therefore, in the present embodiment, the control unit 100 determines the influence of a temperature increase due to opening and closing of the heat insulating door 6a etc. on the ice film on the surface of the food. Based on the determination result, the control unit 100 appropriately controls the dampers 34a and 34b, the bottom heater 35, and the freezing fan 14 to re-form and recover the ice film on the food surface. , the state quickly returns to the state controlled by the "switching chamber ice crystal control".

<Control for temperature rise when opening/closing the door>
(Overall flow)
Next, the flow of control when opening and closing the door will be explained.
FIG. 6 is a diagram showing the flow of control when opening and closing the door in the embodiment. As a premise, it is assumed that the switching compartment ice crystal control is being executed in the small freezer compartment 6.
First, the control unit 100 determines whether the opening of the heat insulating door 6a is detected by the switch 36 (step S1). The heat insulating door 5a and the heat insulating door 7a are also provided with sensors that detect the opening and closing of the door, and the control unit 100 determines whether any of the heat insulating door 5a, the heat insulating door 6a, and the heat insulating door 7a is opened. You may. The following explanation will be given using the case where the heat insulating door 6a is opened, but the same applies to the case where the heat insulating door 5a or the heat insulating door 7a is opened. If opening of the heat insulating door 6a is not detected (step S1; No), the control unit 100 continues the switching room ice crystal control.

When the opening of the heat insulating door 6a is detected (Step S1; Yes), the control unit 100 closes the dampers 34a and 34b, stops the bottom heater 35, and stops the freezing fan 14 (Step S2). As a result, the operation of the component that causes temperature fluctuations in the small freezer compartment 6 is stopped or set in a direction that does not affect the temperature, and the temperature of the small freezer compartment 6 is stabilized.

Next, the control unit 100 determines whether the switch 36 detects that the heat insulating door 6a is closed (step S3). When the closing of the heat insulating door 6a is not detected (step S3; No), the control unit 100 closes the dampers 34a and 34b, stops the bottom heater 35, and continues the stopped state of the freezing blower fan 14.

When the closing of the heat insulating door 6a is detected (Step S3; Yes), the control unit 100 closes the dampers 34a and 34b and starts the freezing fan 14 while keeping the bottom heater 35 stopped (Step S4). After the insulation door 6a is closed, the freezing fan 14 is activated to cool the freezer compartment 7 and the ice making compartment 5, but the small freezer compartment 6 is used to determine the state of the ice film on the food surface by opening and closing the insulation door 6a. Then, the dampers 34a and 34b are closed and the bottom heater 35 is kept stopped to suppress temperature fluctuations in the small freezer compartment 6. Then, the control unit 100 waits for a predetermined time in this state (step S5). The temperature detected by the small freezer compartment temperature sensor 37 is used to determine the state of the ice film; however, the detected temperature may fluctuate depending on the situation for a while after the insulation door 6a is opened/closed. Not suitable. Therefore, by waiting for a predetermined period of time (for example, 1 minute after the door is closed), the temperature detected by the small freezer temperature sensor 37 stabilizes and waits until it can be used for determination.

After a predetermined period of time has elapsed, the control unit 100 acquires the temperature detected by the small freezer temperature sensor 37 and determines the state of the ice film (step S6). The determination method will be explained next using FIG. 7. The control unit 100 controls the temperature of the small freezer compartment 6 according to the determination result of the state of the ice film (step S7). This temperature control compensates for the effect of temperature rise due to opening and closing of the heat insulating door 6a, etc., and also restores the state of the ice film on the surface of the food, so that normal switching chamber ice crystal control can be quickly restored. The temperature control method according to the determination result will be explained using FIGS. 8 to 11.

(Method of determining ice film condition)
Next, a method for determining the state of the ice film on the food surface will be described with reference to FIG.
FIG. 7 is a diagram illustrating an example of a method for determining the state of an ice film (S6 in FIG. 6).
First, the control unit 100 obtains the temperature T of the small freezer compartment 6 (step S101). The control unit 100 determines whether high temperature cooling control is currently being executed in the switching chamber ice crystal control (step S102). If the high temperature cooling control is being executed (step S102; Yes), the control unit 100 determines whether the acquired temperature T is higher than the high temperature target temperature+the ice film disappearance threshold (step S103). The high temperature target temperature is, for example, 1°C, and the ice film disappearance threshold is, for example, +4°C. In this example, the control unit 100 determines whether the temperature T of the small freezer compartment 6 is higher than 5°C. If the temperature T is higher than the high temperature target temperature + the ice film disappearance threshold (step S103; Yes), the control unit 100 determines that the degree of damage to the ice film is large (step S105). A state where the degree of damage is large means that the ice film has disappeared or that the formation of the ice film is inhibited. If the degree of damage is large, as will be explained next with reference to FIG. Perform formation. The ice film disappearance threshold is an example of a "first threshold". The temperature T is an example of a "judgment temperature."

If the temperature T is equal to or lower than the high temperature target temperature + the ice film reduction threshold (step S103; No), the control unit 100 determines whether the acquired temperature T is higher than the high temperature target temperature + the ice film shrinkage threshold (step S107). The high temperature target temperature is, for example, 1°C, and the ice film shrinkage threshold is, for example, +2°C. In this example, the control unit 100 determines whether the temperature T of the small freezer compartment 6 is higher than 3°C. If the temperature T is higher than the high temperature target temperature + the ice film reduction threshold (step S107; Yes), the control unit 100 determines that the damage to the ice film is moderate (step S110). Moderate damage to the ice film means that although the ice film has not completely disappeared, the ice film has been reduced by opening and closing the door. If the damage is moderate, the control unit 100 provides a period for recovering the ice film, as will be explained next with reference to FIG. After that, the control unit 100 continues the high temperature cooling control that has been executed so far. If the temperature T is equal to or lower than the high temperature target temperature+the ice film reduction threshold (step S107; No), the control unit 100 determines that the degree of damage to the ice film is small (step S109). If the degree of damage is small, the control unit 100 continues the high-temperature cooling control that has been performed so far, as will be explained next with reference to FIG. The ice film reduction threshold is an example of a "third threshold".

If high-temperature cooling control is not being executed, that is, if low-temperature cooling control is being executed (step S102; No), the control unit 100 determines whether the acquired temperature T is higher than the low-temperature target temperature + the ice film formation inhibition threshold. is determined (step S104). The low temperature target temperature is, for example, -5°C, and the ice film formation inhibition threshold is, for example, +7°C. In this example, the control unit 100 determines whether the temperature T of the small freezer compartment 6 is higher than 2°C. If the temperature T is higher than the high temperature target temperature + the ice film formation inhibition threshold (step S104; Yes), the control unit 100 determines that the degree of damage to the ice film is large (step S106). If the degree of damage is large, as will be explained next with reference to FIG. Perform formation. The ice film formation inhibition threshold is an example of a "second threshold".

If the temperature T is lower than or equal to the low-temperature target temperature + the ice film formation inhibition threshold (step S104; No), the control unit 100 determines whether the acquired temperature T is higher than the low-temperature target temperature + the ice film formation delay threshold. (Step S108). The low temperature target temperature is -5°C, and the ice film formation delay threshold is, for example, +2°C. In this example, the control unit 100 determines whether the temperature T of the small freezer compartment 6 is higher than -3°C. If the temperature T is higher than the low-temperature target temperature + the ice film formation delay threshold (step S108; Yes), the control unit 100 determines that the damage to the ice film is moderate (step S112). If the damage is moderate, the control unit 100 provides a period for recovering the ice film, as will be explained next with reference to FIG. After that, the control unit 100 continues the low-temperature cooling control that has been executed so far. If the temperature T is equal to or lower than the low-temperature target temperature+the ice film formation delay threshold (step S108; No), the control unit 100 determines that the degree of damage to the ice film is small (step S111). If the degree of damage is small, the control unit 100 continues the low-temperature cooling control that has been performed so far, as will be explained next with reference to FIG. The ice film formation delay threshold is an example of a "fourth threshold".

(Temperature control of high temperature cooling control)
Next, referring to FIG. 8, temperature control when the heat insulating door 6a or the like is opened or closed during high temperature cooling control will be described.
If it is determined in the flowchart of FIG. 7 that the damage to the ice film is large (step S201; large), the ice film on the surface of the food in the small freezer compartment 6 has disappeared, or the temperature rise including the load has increased to a high temperature. It is determined that continuing the cooling control is not sufficient, so the high-temperature cooling control that has been in progress is stopped and the ice film on the food surface is re-formed. In other words, the high-temperature cooling control that has been executed so far is canceled and a new low-temperature cooling control is started. Therefore, the control unit 100 sets the center temperature of the first temperature zone, that is, the low-temperature target temperature (for example, -5° C.) as the target temperature of the small freezer compartment 6 (step S203).

If the degree of damage is determined to be medium (step S201; medium), the ice film has not disappeared but has shrunk by opening and closing the door, or the input load can be handled even if high temperature cooling control is continued. It is determined that From the opposite point of view, if low-temperature cooling control is performed, it is determined that high-temperature cooling control should be maintained because harmful effects (for example, decrease in freshness) due to an increase in ice film due to over-chilling of the food occur. Therefore, the control unit 100 sets the center temperature of the second temperature zone, that is, the high temperature target temperature (for example, 1° C.) as the target temperature of the small freezer compartment 6 (step S202).

If it is determined that the degree of damage is small (step S201; small), it is determined that there is no influence on ice film formation. The control unit 100 continues to perform the high temperature cooling control of the switching chamber ice crystal control that has been performed so far (step S215).

When it is determined that the degree of damage is large or medium, the control unit 100 sets the target temperature + ice film maintenance threshold as the intermediate target temperature and performs cooling (step S204). The intermediate target temperature is a target temperature for temporarily lowering the temperature of the small freezer compartment 6 by, for example, 1° C. from the target temperature in order to compensate for the temperature increase due to opening and closing of the door. The ice film maintenance threshold is, for example, -1°C. Specifically, if the degree of damage is determined to be large, the intermediate target temperature is, for example, -6°C, and if the degree of damage is determined to be medium, the intermediate target temperature is, for example, 0°C. be. The absolute value of the ice film maintenance threshold is an example of a "maintenance threshold."

Next, the control unit 100 determines whether the basic operation of the refrigerator 1 is a refrigeration operation (step S205). If the refrigeration operation is in progress (step S205; Yes), the control unit 100 stops the bottom heater 35, closes the dampers 34a and 34b, and stops the refrigeration fan 14 (step S206). If the dampers 34a and 34b are opened during refrigeration operation, the temperature of the small freezer compartment 6 will not drop because the freezing fan 14 is not rotating. If the freezing fan 14 is started, the temperature of the ice making compartment 5 and the freezing compartment 7 will increase. Therefore, during the refrigeration operation, the temperature of the small freezer compartment 6 is gradually lowered due to the temperature difference between the temperature of the surroundings such as the ice making compartment 5 and the freezing compartment 7.

If the refrigeration operation is in progress (step S205; No), the control unit 100 stops the bottom heater 35, opens the dampers 34a and 34b, and starts the refrigeration blower fan 14 (step S207). The temperature of the small freezer compartment 6 is lowered by opening the dampers 34a and 34b and starting the freezing fan 14. During the freezing operation, the temperature is lowered to the target temperature by "opening" the dampers 34a and 34b. If the freezing operation is in progress, adverse effects on the ice making compartment 5 and the freezing compartment 7 can be suppressed. However, the purpose of reducing the temperature by opening the dampers 34a and 34b is to rapidly lower the temperature of the small freezer compartment 6 by using the air that cools the freezer compartment 7, etc., and cool air is applied directly to the food. Since the purpose is not to cool (freeze), it is performed in a limited manner, for example, only during the period until the temperature of the small freezer compartment 6 reaches the target temperature.

The control unit 100 determines whether the temperature of the small freezer compartment 6 detected by the small freezer compartment temperature sensor 37 has reached the target temperature (step S208). If the degree of damage is determined to be large, the target temperature is, for example, -5°C, and if the degree of damage is determined to be medium, the target temperature is, for example, 1°C. If the target temperature has not been reached (step S208; No), the process from step S205 is repeated.

When the temperature of the small freezer compartment 6 reaches the target temperature (step S208; Yes), the control unit 100 calculates the maintenance time (step S209). The maintenance time is a time period during which the target temperature is maintained as a temporary target temperature of the small freezer compartment 6. Here, reference is made to FIG. FIG. 9 is a diagram for explaining the maintenance time. The vertical axis in FIG. 9 represents temperature, and the horizontal axis represents time. The control unit 100 uses the timer 101 to set the temperature of the small freezer compartment 6 to the target temperature (for example, -5°C or 1°C) after the switch 36 detects the opening of the heat insulating door 6a and after closing the heat insulating door 6a. Measure the time Ta until reaching . The control unit 100 calculates a heat capacity F1 that can be calculated from this time Ta and the difference between the temperature of the small freezer compartment 6 after a predetermined period of time has passed since the insulation door 6a is closed (the temperature in step S101 in FIG. 7) and the target temperature. calculate. The heat capacity F1 is a heat capacity that increases in accordance with the temperature rise due to opening and closing of the heat insulating door 6a. The heat capacity F1 corresponds to the area of the region D91 in FIG. The control unit 100 calculates the heat capacity F2, which can be calculated based on the elapsed time after reaching the target temperature and the difference between the temperature of the small freezer compartment 6 after reaching the target temperature and the target temperature. The heat capacity F2 corresponds to the area of the region D92 in FIG. The control unit 100 calculates a time Tb until the heat capacity F2 reaches a heat capacity corresponding to the heat capacity F1, or a time Tc proportional to the time Tb, and sets the time Tb or the time Tc as a maintenance time. The maintenance time is a time period during which the heat capacity of the small freezer compartment 6 can be reduced by the heat capacity F2 corresponding to the heat capacity F1 increased by opening and closing the door. The control unit 100 sets the intermediate target temperature and performs temperature control with the intermediate target temperature as a target until the calculated maintenance time (for example, time Tb) elapses after cooling is started.

Further, the control unit 100 determines whether the refrigeration operation is in progress (step S210), and if the refrigeration operation is in progress (step S210; Yes), the control unit 100 stops the bottom heater 35 and turns the dampers 34a and 34b on. The refrigerator is closed, and the freezing fan 14 is stopped (step S211).

If the freezing operation is in progress (step S210; No), the control unit 100 stops the bottom heater 35, closes the dampers 34a and 34b, and starts the freezing fan 14 (step S212). After reaching the low-temperature target temperature, the dampers 34a and 34b are closed, and the temperature of the small freezing compartment 6 is gradually lowered by the temperature difference between the temperature of the surroundings such as the ice making compartment 5 and the freezing compartment 7.

The control unit 100 determines whether the temperature of the small freezer compartment 6 has reached the target temperature (for example, −6° C. or 0° C.) (step S213). If the target temperature has not been reached midway (step S213; No), the process from step S210 is repeated. When the target temperature is reached midway (step S213; Yes), the control unit 100 determines whether the maintenance time has elapsed (step S214). If the maintenance time has not elapsed (step S214; No), the process waits until the maintenance time has elapsed. If the maintenance time has elapsed (step S214; Yes), the control unit 100 performs normal switching chamber ice crystal control according to the target temperature (step S215). For example, if it is determined that the degree of damage is large, the control unit 100 executes low-temperature cooling control from the beginning. For example, the control unit 100 controls the temperature of the small freezer compartment 6 to a low-temperature target temperature by PID control of the bottom heater 35. Furthermore, if the degree of damage is determined to be medium or small, the control unit 100 continues to perform the high temperature cooling control that has been performed so far. For example, the control unit 100 controls the temperature of the small freezer compartment 6 to a high target temperature by PID control of the bottom heater 35.

(Temperature control of low temperature cooling control)
Next, referring to FIG. 10, temperature control when the heat insulating door 6a is opened and closed during low temperature cooling control will be described.
If it is determined in the flowchart of FIG. 7 that the damage to the ice film is large (step S301; large), a severe failure has occurred in the formation of the ice film on the surface of the food in the small freezer compartment 6, or new food must be introduced. Continuing low-temperature cooling control will not be able to cope with the temperature rise, including the minute temperature increase, and if ice film does not form if low-temperature cooling control continues, there is a possibility that food quality will be adversely affected when switching to high-temperature cooling control. It is determined that there is. Therefore, reformation of the ice film on the food surface is carried out. That is, the low-temperature cooling control that has been executed so far is canceled and the low-temperature cooling control is newly executed from the beginning. The control unit 100 sets the center temperature of the first temperature zone, that is, the low temperature target temperature (for example, −5° C.) as the target temperature of the small freezer compartment 6 (step S303).

If the degree of damage is determined to be medium (step S301; medium), food that does not reach the level of "severe impairment in ice film formation" but has delayed ice film formation due to door opening/closing, or food that has been newly introduced. It is determined that the load can be handled by continuing low-temperature cooling control. From the opposite point of view, starting low-temperature cooling control again (restarting the 2-hour process from the beginning) will cause adverse effects (for example, decreased freshness) due to an increase in ice film due to over-chilling of existing foods. It is determined that cooling control should be continued. The control unit 100 sets the center temperature of the first temperature zone, that is, the low temperature target temperature (for example, −5° C.) as the target temperature of the small freezer compartment 6 (step S302).

If it is determined that the degree of damage is small (step S301; small), it is determined that there is no influence on ice film formation. The control unit 100 continues to perform the low-temperature cooling control that has been performed so far (step S319).

If the degree of damage is determined to be large or medium, the control unit 100 sets the target temperature + ice film maintenance threshold as the intermediate target temperature and performs cooling (step S304). For example, the ice film maintenance threshold is -1°C, and the intermediate target temperature is -6°C.

Next, the control unit 100 determines whether the temperature T after a predetermined period of time has passed since the insulation door 6a is closed exceeds the low-temperature target temperature+the damper opening threshold (step S305). If a temperature rise occurs due to door opening/closing during low-temperature cooling control, the temperature may fall between the high-temperature target temperature and the low-temperature target temperature, but in this case, when the refrigerator 1 switches to freezing operation, the small freezer compartment In a situation where the temperature of the air conditioner 6 has fallen close to the low-temperature target temperature (for example, -5° C.), opening of the dampers 34a and 34b may cause an adverse effect (overcooling). Therefore, a damper opening threshold is provided to determine whether or not to open the dampers 34a, 34b. The control unit 100 determines whether the temperature T exceeds the low-temperature target temperature+the damper opening threshold (step S305), and if it exceeds the temperature T, further determines whether the refrigerator 1 is in a freezing operation (step S306). If the temperature T exceeds the low-temperature target temperature + the damper opening threshold (step S305; Yes) and the freezing operation is in progress (step S306; Yes), the control unit 100 stops the bottom heater 35, The dampers 34a and 34b are opened (step S307). Thereby, the dampers 34a and 34b are "opened" to lower the temperature to the target temperature (for example, around -5° C.). Even if the temperature T is lower than the low temperature target temperature + damper open threshold (step S305; No), or even if the temperature T acquired in step S101 of FIG. 7 exceeds the low temperature target temperature + damper open threshold (step S305; Yes). ), if the refrigeration operation is in progress (step S306; No), the control unit 100 stops the bottom heater 35 and closes the dampers 34a and 34b (step S308). Thereby, the temperature of the small freezer compartment 6 is gradually lowered due to the temperature difference between the temperature of the surroundings such as the ice making compartment 5 and the freezing compartment 7. By reducing the temperature through indirect cooling, a balance is maintained with the temperature increase caused by opening and closing the door. The damper opening threshold is an example of a "fifth threshold".

Next, the control unit 100 determines whether the basic operation of the refrigerator 1 is a refrigeration operation (step S309). If the refrigeration operation is in progress (step S309; Yes), the control unit 100 stops the refrigeration fan 14 (step S310). If the refrigeration operation is in progress (step S309; No), the control unit 100 starts the refrigeration blower fan 14 (step S311). By starting the freezing fan 14, the temperature of the small freezer compartment 6 is lowered.

The control unit 100 determines whether the temperature of the small freezer compartment 6 detected by the small freezer compartment temperature sensor 37 has reached the target temperature (step S312). The target temperature is, for example, -5°C. If the target temperature has not been reached (step S312; No), the process from step S305 is repeated.

When the temperature of the small freezer compartment 6 reaches the target temperature (step S312; Yes), the control unit 100 calculates the maintenance time (step S313). This process is similar to step S209. Further, the control unit 100 determines whether the refrigeration operation is in progress (step S314), and if the refrigeration operation is in progress (step S314; Yes), the control unit 100 stops the bottom heater 35 and turns the dampers 34a and 34b on. The refrigerator is closed, and the refrigeration blower fan 14 is stopped (step S315). If the freezing operation is in progress (step S314; No), the control unit 100 stops the bottom heater 35, closes the dampers 34a and 34b, and starts the freezing fan 14 (step S316). After reaching the low-temperature target temperature, the dampers 34a and 34b are closed, and the temperature of the small freezing compartment 6 is gradually lowered by the temperature difference between the temperature of the surroundings such as the ice making compartment 5 and the freezing compartment 7.

The control unit 100 determines whether the temperature of the small freezer compartment 6 has reached the target temperature (for example, −6° C.) (step S317). If the target temperature has not yet been reached (step S317; No), the process from step S314 is repeated. When the target temperature is reached midway (step S317; Yes), the control unit 100 determines whether the maintenance time has elapsed (step S318). If the maintenance time has not elapsed (step S318; No), the system waits while maintaining the target temperature by PID control of the bottom heater 35 until the maintenance time elapses. When the maintenance time has elapsed (step S318; Yes), the control unit 100 executes low-temperature cooling control (step S319). For example, if it is determined that the degree of damage is large, the control unit 100 executes low-temperature cooling control from the beginning. For example, if the degree of damage is determined to be medium or small, the control unit 100 continues low-temperature cooling control. For example, the control unit 100 controls the temperature of the small freezer compartment 6 to a low-temperature target temperature by PID control of the bottom heater 35.

FIGS. 11 and 12 show an example of temperature control during door opening/closing according to this embodiment. The vertical axis in FIGS. 11 and 12 indicates the temperature of the small freezer compartment 6, and the horizontal axis indicates time. Graph L1 shows the change in temperature when the heat insulating door 6a is opened and closed, and graph L2 shows the change in temperature when normal switching room ice crystal control is performed. Refer to FIG. 11. When the heat insulating door 6a is opened at time t1 during high temperature freezing control, the control unit 100 stops the bottom heater 35, closes the dampers 34a and 34b, and stops the freezing fan 14. After that, the temperature of the small freezer compartment 6 rises and exceeds the high temperature target temperature + the ice film disappearance threshold (large damage occurs during high temperature cooling control). Then, the control unit 100 performs cooling targeting the low temperature target temperature + ice film maintenance threshold. When the refrigerator 1 is in refrigeration operation, the control unit 100 stops the bottom heater 35, closes the dampers 34a and 34b, and stops the freezing fan 14 to adjust the temperature of the small freezing compartment 6 to the ice making compartment 5. The temperature is gradually lowered depending on the temperature difference between the temperature and the ambient temperature of the freezer compartment 7, etc. (times t2 to t3). Further, when the refrigerator 1 is in the freezing operation, the control unit 100 stops the bottom heater 35, opens the dampers 34a and 34b, and starts the freezing fan 14 to perform cooling (times t3 to t4). When the temperature of the small freezer compartment 6 reaches the low-temperature target temperature (time t4), the control unit 100 stops the bottom heater 35, closes the dampers 34a and 34b, and stops the freezing fan 14. When the temperature reaches the low-temperature target temperature + ice film maintenance threshold, the low-temperature cooling control is restarted if the maintenance time has elapsed since cooling started with the low-temperature target temperature + ice film maintenance threshold as the intermediate target temperature. Start (time t5). As a result, the switching chamber ice crystal control that has been performed so far is canceled and the ice film on the food surface begins to be re-formed. The control unit 100 starts the bottom heater 35 and controls the temperature of the small freezer compartment 6 to a low-temperature target temperature by PID control.

Next, refer to FIG. When the heat insulating door 6a is opened at time t1 during high temperature freezing control, the control unit 100 stops the bottom heater 35, the dampers 34a and 34b, and the freezing fan 14. Thereafter, the temperature of the small freezer compartment 6 rises, and although it does not exceed the high temperature target temperature + extinction threshold, it exceeds the high temperature target temperature + ice film shrinkage threshold (damage is moderate during high temperature cooling control). Then, the control unit 100 performs cooling targeting the high temperature target temperature + ice film maintenance threshold. When the refrigerator 1 is in refrigeration operation, the control unit 100 stops the bottom heater 35, the dampers 34a and 34b, and the freezing fan 14 to adjust the temperature of the small freezing compartment 6 to the ice making compartment 5. The temperature is gradually lowered depending on the temperature difference between the temperature and the ambient temperature of the freezer compartment 7, etc. (times t2 to t3). Further, when the refrigerator 1 is in a freezing operation, the control unit 100 stops the bottom heater 35, stops the dampers 34a and 34b, and starts the freezing fan 14 to perform cooling. When the temperature of the small freezing compartment 6 reaches the low-temperature target temperature, the control unit 100 stops the bottom heater 35 and the dampers 34a and 34b, so that the temperature of the small freezing compartment 6 reaches the high-temperature target temperature + the ice film maintenance threshold. When reaching , if the maintenance time has elapsed since the start of cooling with the target high temperature target temperature + ice film maintenance threshold value as a target, low temperature cooling control is continued (time t4). The control unit 100 starts the bottom heater 35 and controls the temperature of the small freezer compartment 6 to a high target temperature by PID control.

When the insulation door 6a is opened at time t5 during low-temperature freezing control, the control unit 100 stops the bottom heater 35, the dampers 34a and 34b, and the freezing fan 14. After that, the temperature of the small freezer compartment 6 rises and exceeds the low-temperature target temperature + the ice film formation delay threshold (the low-temperature target temperature + the damper opening threshold does not exceed). Then, the control unit 100 performs cooling targeting the low temperature target temperature + ice film maintenance threshold. If the refrigerator 1 is in the refrigeration operation, the control unit 100 stops the bottom heater 35, the dampers 34a and 34b, and the freezing fan 14. 35, the dampers 34a and 34b, and the freezing blower fan 14 are started to cool the small freezer compartment 6. When the temperature of the small freezer compartment 6 reaches the low-temperature target temperature (time t7), the control unit 100 stops the bottom heater 35, stops the dampers 34a and 34b, stops the freezing fan 14 (during refrigeration operation), or stops the freezing operation. When the ventilation fan 14 is started (during freezing operation) and the temperature of the small freezer compartment 6 reaches the low-temperature target temperature + ice film maintenance threshold, cooling starts with the target low-temperature target temperature + ice film maintenance threshold. If the maintenance time has elapsed since then, the low temperature cooling control is continued (time t4). The control unit 100 starts the bottom heater 35 and controls the temperature of the small freezer compartment 6 to a low-temperature target temperature by PID control.

As described above, in the present embodiment, the control unit 100 stops the bottom heater 35, closes the dampers 34a and 34b, and stops the freezing fan 14, and temporarily interrupts the switching chamber ice crystal control. Then, the temperature T of the small freezer compartment 6 after a predetermined time has elapsed after opening and closing of the door 6a etc. is obtained, and based on the temperature T, the degree of damage to the ice film of the food is determined. Then, depending on the degree of damage, the temperature of the small freezer compartment 6 is temporarily lowered to the target temperature, and while balancing with the temperature increase, the ice film can be started to re-form or the ice film can be recovered. to execute low-temperature cooling control or high-temperature cooling control, and return to normal switching chamber ice crystal control. Thereby, damage to the ice film of the food due to opening and closing of the door 6a etc. can be prevented.

(Second embodiment)
Next, a second embodiment will be described. In the second embodiment, processing is performed to deal with the influence of the defrosting operation on the freezing cooler 12 on the temperature of the small freezer compartment 6 during which the switching compartment ice crystal control is being executed. The defrosting operation for the freezing cooler 12 is performed, for example, once a day. Since the defrosting heater 15 is heated during the defrosting operation, the temperature of the small freezer compartment 6 rises. As shown in FIG. 13, if a temperature rise occurs during high-temperature cooling control or low-temperature cooling control of freezing chilled control, it may have an adverse effect on the ice film on the surface of the food. However, if the execution timing of the defrost operation can be moved forward or backward so that the defrost heater 15 is heated when the temperature rises in the freezing chilled control, the heat of the defrost heater 15 can be effectively used to raise the temperature of the small freezer compartment 6. be able to.

FIG. 14 shows an example in which the heat of the defrosting heater 15 is effectively used to raise the temperature of the small freezer compartment 6.
For example, at the start of the switching chamber ice crystal control, the control unit 100 may synchronize the time to start the high temperature cooling control and the time to execute the defrosting operation, and perform these simultaneously or in parallel. After (Tw1), high temperature cooling control is started. The temperature of the small freezer compartment 6 is raised by the heat from the defrosting heater 15, and after the defrosting operation is finished, the temperature of the small freezer compartment 6 is raised to the high temperature target temperature by the heating of the bottom heater 35. Thereby, the heat of the defrosting heater 15 can be effectively used to raise the temperature of the small freezer compartment 6. Moreover, the time required for temperature increase can be shortened.

For example, the control unit 100 matches the timing of switching from low-temperature cooling control to high-temperature cooling control with the timing of executing the defrosting operation, and sets the high-temperature target at the same time as switching to high-temperature cooling control, or after switching to high-temperature cooling control. These are performed in parallel before reaching the temperature (Tw3). Thereby, the heat of the defrosting heater 15 can be effectively used to raise the temperature of the small freezer compartment 6. Moreover, the time required for temperature increase can be shortened.

During the defrosting operation for the refrigeration cooler 12, the refrigeration blower fan 14 is stopped during the heating period of the defrost heater 15 and for a predetermined period of time (for example, 10 minutes) after the defrost heater 15 is stopped. Because it is a period, the small freezer compartment 6 is not cooled either. By raising the temperature of the small freezer compartment 6 using the bottom heater 35 during this period after the defrosting operation, the temperature can be raised efficiently. Further, the defrosting heater 15 does not support duty control, but the bottom heater 35 can perform duty control. Therefore, by performing a defrosting operation first, and after raising the temperature of the small freezer compartment 6 by the defrosting heater 15, by raising the temperature by the bottom heater 35, the defrosting heater 15 is used to bring the temperature close to the target temperature to a certain extent. Control such as raising the temperature to the target temperature using the bottom heater 35 after the defrosting heater 15 is stopped becomes possible, and the target temperature can be efficiently achieved.

Further, if the refrigerator 1 is in a freezing operation immediately before switching from low-temperature cooling control to high-temperature cooling control (Tw2), that is, immediately before heating the defrosting heater 15, the control unit 100 opens the dampers 34a and 34b. can do. Thereby, precooling is performed to temporarily lower the temperature of the small freezer compartment 6. This can be expected to prevent an overshoot in the temperature of the small freezer compartment 6 after the temperature rise. Instead of this, or in addition to this, the control unit 100 may stop the bottom heater 35 immediately before heating the defrosting heater 15 (Tw2). Thereby, it is possible to pre-cool the small freezer compartment 6 and prevent an overshoot in the temperature of the small freezer compartment 6 caused by performing high temperature cooling control and defrosting operation simultaneously.

According to the present embodiment, the control unit 100 performs temperature increase in the switching room ice crystal control by combining the defrosting heater 15 and the bottom heater 35 when executing the defrosting operation for the freezing cooler 12. Thereby, the temperature of the small freezer compartment 6 can be raised efficiently. Moreover, by operating the defrosting heater 15 during temperature rise in the switching chamber ice crystal control, overshoot during high-temperature cooling control and low-temperature cooling control can be avoided and adverse effects on food products can be prevented.

(Third embodiment)
Next, a third embodiment will be described. In the third embodiment, processing is performed to deal with the influence of the refrigeration operation and freezing operation of the refrigerator 1 on the temperature of the small freezer compartment 6 during which the switching compartment ice crystal control is being executed. FIG. 15 shows a time-series graph L3 representing repeated execution of refrigeration operation and freezing operation, and a time-series graph L4 representing repeated execution of high-temperature cooling control and low-temperature cooling control in freezing chilled control. In the case of FIG. 15, from time t1 to time t2, the control unit 100 opens the dampers 34a and 34b, starts the freezing fan 14, and lowers the temperature of the small freezer compartment 6. On the other hand, the control unit 100 performs the refrigeration operation during the same time period. If the freezing fan 14 is rotated during the refrigeration operation, there is a risk that the temperature of the storage compartments (ice making compartment 5, small freezing compartment 6, freezing compartment 7) in the freezing temperature range will increase. Further, from time t3 to time t4, the control unit 100 raises the temperature of the small freezer compartment 6 by heating the bottom heater 35. On the other hand, the control unit 100 performs the refrigeration operation during the same time period. It is more efficient to raise the temperature of the small freezer compartment 6 during the refrigeration operation than during the refrigeration operation.

FIG. 16 shows an example in which high-temperature cooling control is switched to low-temperature cooling control during freezing operation of the refrigerator 1, and low-temperature cooling control is switched to high-temperature cooling control during refrigeration operation. The storage unit 116 stores information about how long it will take and how many degrees Celsius the temperature of the small freezer compartment 6 will be when the dampers 34a and 34b are opened and the freezing fan 14 is rotated at a predetermined rotation speed during freezing operation. Tables, functions, etc. that determine what can be lowered are recorded in advance. The control unit 100 switches from high-temperature cooling control to low-temperature cooling control during refrigeration operation. At this time, the control unit 100 calculates the time required for transition from the high temperature target temperature to the low temperature target temperature using a function stored in the storage unit 116, and sets the temperature of the small freezer compartment 6 to a high temperature during the freezing operation. The switching start time is calculated so that the temperature can be lowered from the target temperature to the low temperature target temperature. At the calculated switching start time during the refrigeration operation, the control unit 100 opens the dampers 34a and 34b, starts the refrigeration blower fan 14, and switches from high-temperature cooling control to low-temperature cooling control. Lines L41 to L43 representing the temperature drop when switching is performed in this manner are shown. In the case of L41, the freezing operation is executed when the temperature of the small freezer compartment 6 reaches the low temperature target temperature, and there is a possibility of undershoot, but in the refrigerating operation, the temperature of the small freezer compartment 6 is maintained. Therefore, it is preferable to switch from high-temperature cooling control to low-temperature cooling control at a time when the time when the low-temperature target temperature is reached and the period of refrigeration operation overlap (L42, L43). The control unit 100 calculates a switching start time during the refrigeration operation and at which the time when the low-temperature target temperature is reached overlaps with the period of the refrigeration operation or overlaps with the start time of the refrigeration operation. Further, referring to time t3 to t4 in FIG. 16, during the refrigeration operation, the low temperature cooling control is switched to the high temperature cooling control. Thereby, the temperature of the small freezer compartment 6 can be raised to the high temperature target temperature more efficiently than during the freezing operation. Note that switching from low-temperature cooling control to high-temperature cooling control is not limited to during refrigeration operation, but can also be performed in storage compartments in the freezing temperature range (ice making compartment 5, small freezing compartment 6, freezing compartment 7) during refrigerant recovery, cooling stop, etc. It may also be executed during other periods when cooling is not performed.

Further, the control unit 100 may adjust the timing of switching from low-temperature cooling control to high-temperature cooling control so that the freezing operation is executed immediately after switching from low-temperature cooling control to high-temperature cooling control. Thereby, overshoot that tends to occur when the temperature is increased for high-temperature cooling control can be suppressed by using the cooling of the refrigeration operation.

In addition, with regard to adjusting the switching from low-temperature cooling control to high-temperature cooling control to be performed during refrigeration operation, and adjusting the switching from high-temperature cooling control to low-temperature cooling control to be performed during refrigeration operation, for example, it is necessary to always control low-temperature cooling control. If the period (for example, 2 hours) is adjusted to be shorter or longer, the low temperature cooling control will be too short or too long, and the quality of the food will be adversely affected. Therefore, in order to switch from low-temperature cooling control to high-temperature cooling control, for example, if the low-temperature cooling control is extended by one freezing operation, the controller 100 then switches from low-temperature cooling control to high-temperature cooling. When switching to high-temperature cooling control, in order to compensate for the extended time last time, the execution time of low-temperature cooling control is shortened, and the switch from low-temperature cooling control to high-temperature cooling control is executed early, so that the So that the total execution time of low-temperature cooling control is equal to the total execution time of low-temperature cooling control when low-temperature cooling control and high-temperature cooling control are executed alternately as usual (or so that both are as close as possible) Calculate the timing of switching from low-temperature cooling control to high-temperature cooling control each time. The control unit 100 pays attention to the execution time of the high-temperature cooling control, and determines whether the total execution time of the high-temperature cooling control in a predetermined period (for example, one day) is the same as when the low-temperature cooling control and the high-temperature cooling control are alternately executed as usual. The switching timing from high-temperature cooling control to low-temperature cooling control may be calculated so as to be equal to the total execution time of high-temperature cooling control.

According to the present embodiment, the control unit 100 switches between low-temperature cooling control and high-temperature cooling control in accordance with the refrigerating operation or the freezing operation, thereby realizing efficient operation that suppresses the energy consumption required for operating the refrigerator 1. be able to. Furthermore, if refrigeration operation is being performed when switching from high-temperature cooling control to low-temperature cooling control, there is a risk that the temperature of the small freezer compartment 6 will rise, but this embodiment prevents the temperature rise of the small freezer compartment 6. , food quality can be maintained.

(Fourth embodiment)
Next, a fourth embodiment will be described. In the fourth embodiment, when refrigeration operation and high-temperature cooling control are executed, there is a possibility that an overshoot occurs in the temperature of the small freezer compartment 6, and when refrigeration operation and low-temperature cooling control are executed, Control is performed to prevent the possibility of undershoot occurring in the temperature of the freezer compartment 6. From time t1 to time t4 in FIG. 17, low temperature cooling control is executed in the small freezer compartment 6. During this period, from time t1 to t2, the refrigerator 1 performs the freezing operation, and from the following time t2 to t3, the refrigerator 1 performs the refrigerating operation. In the low-temperature cooling control, PID control of the bottom heater 35 is performed so that the temperature of the small freezer compartment 6 is set to a low-temperature target temperature (for example, -5° C.) regardless of whether the refrigerator 1 is in a refrigerating operation or a freezing operation. Then, during times t1 to t2 during the freezing operation, since the cooling component is stronger than during the refrigeration operation, the control unit 100 heats the bottom heater 35 more strongly than during the refrigeration operation to maintain the low-temperature target temperature. try to. While such control is being performed, when the freezing operation is switched to the refrigeration operation at time t2, the cooling component transmitted to the small freezer compartment 6 becomes weaker than during the freezing operation. Then, since the conventional bottom heater 35 is heated too strongly, overshoot from the low-temperature target temperature is likely to occur in the small freezer compartment 6. Since overheating is gradually suppressed by PID control, the target temperature is eventually set to a low temperature, but due to the characteristics of feedback control, it takes time compared to the switching time from freezing operation to refrigeration operation. Even if overshoot in low-temperature cooling control has a small effect on food, it is preferable to suppress excessive heating of the bottom heater 35 in order to suppress power consumption. For the same reason, undershoot from the low-temperature target temperature is likely to occur between times t3 and t4 when the refrigeration operation is switched to the freezing operation. If excessive undershoot occurs, the food may freeze to the inside, making it impossible to maintain the freshness of the food. It is preferable that undershoot can be suppressed also from the viewpoint of influence on food products.

From time t5 to time t8 in FIG. 17, high temperature cooling control is executed in the small freezer compartment 6. During this period, from time t5 to t6, the refrigerator 1 performs the freezing operation, and from the following time t6 to t7, the refrigerator 1 performs the refrigerating operation. In the high-temperature cooling control, PID control of the bottom heater 35 is performed so that the temperature of the small freezer compartment 6 is set to a high-temperature target temperature (for example, 1° C.) regardless of whether the refrigerator 1 is in a refrigerating operation or a freezing operation. Then, as in the case of low-temperature cooling control, overshoot from the high-temperature target temperature tends to occur between times t6 and t7. Overshoot in high-temperature cooling control may have an adverse effect on food products, and it is preferable to avoid overshoot from the viewpoint of reducing power consumption.

FIG. 18 shows a control to prevent overshoot when switching from freezing operation to refrigeration operation while executing high temperature cooling control, and a control to prevent undershoot when switching from refrigeration operation to freezing operation while executing low temperature cooling control. show. Low temperature cooling control is performed from time t1 to time t5. At time t2, the refrigeration operation is switched to the freezing operation. As a result, undershoot is likely to occur. Therefore, the control unit 100 raises the low temperature target temperature (for example, -5°C) by 0.5°C and resets it to -4.5°C. This intensifies the heating of the bottom heater 35 and makes undershoot less likely to occur. The control unit 100 may keep the low-temperature target temperature raised during execution of the refrigeration operation. When the basic operation of the refrigerator 1 is switched to the refrigeration operation, the control unit 100 returns the low-temperature target temperature to the original temperature, and sets it to, for example, -5°C. Thereby, undershoot during execution of low temperature cooling control can be suppressed.

High temperature cooling control is performed from time t6 to time t9. At time t7, the freezing operation is switched to the refrigeration operation. As a result, overshoot is likely to occur. Therefore, the control unit 100 lowers the high temperature target temperature (for example, 1°C) by 0.5°C and resets it to 0.5°C. This weakens the heating of the bottom heater 35, making overshoot less likely to occur. The control unit 100 may keep the high temperature target temperature raised during execution of the refrigeration operation. When the refrigeration operation is switched to the freezing operation, the control unit 100 returns the high temperature target temperature to the original temperature, and sets it to, for example, 1.0°C. This makes it possible to suppress overshoot during execution of high-temperature cooling control.

According to this embodiment, the control unit 100 can prevent overshoot during high-temperature cooling control due to switching from freezing operation to refrigeration operation. Further, according to the present embodiment, undershoot during low-temperature cooling control due to switching from refrigeration operation to freezing operation can be prevented. This can prevent deterioration of food quality due to overshoot or undershoot from the target temperature.

According to at least one embodiment described above, appropriate temperature control can be performed with respect to temperature changes that affect the freshness of food.

Although several embodiments of the invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included within the scope and gist of the invention as well as within the scope of the invention described in the claims and its equivalents.

DESCRIPTION OF SYMBOLS 1... Refrigerator, 100... Control part, 34a... Damper, 34b... Damper, 35... Bottom heater.

Claims (12)

a housing including a storage section;
a cooling unit that cools the storage unit;
a control unit that controls the temperature of the storage unit;
Equipped with
The control unit is configured to control ice crystals, which alternately repeats low-temperature cooling control in which the storage unit is cooled in a first temperature zone, and high-temperature cooling control in which the storage unit is cooled in a second temperature zone higher than the first temperature zone. When the ice crystal control is executed and the opening/closing of a door provided in the casing is detected during the execution of the ice crystal control, the ice crystal control is interrupted and a predetermined period of time has elapsed since the opening/closing of the door was detected. Determining damage to the ice film on the surface of the food in the storage unit based on a determination temperature that is the temperature of the storage unit after the determination, and controlling the temperature of the storage unit based on the determination.
refrigerator. During execution of the high-temperature cooling control, when the determination temperature rises by more than a first threshold value than the center temperature of the second temperature zone,
The control unit stops the high temperature cooling control and starts the low temperature cooling control,
The refrigerator according to claim 1. During execution of the low-temperature cooling control, when the determination temperature rises by more than a second threshold value than the center temperature of the first temperature zone,
The control unit cancels the low-temperature cooling control that is being executed and starts the low-temperature cooling control anew.
The refrigerator according to claim 2. a blower that sends the air cooled by the cooling unit to the storage unit;
a switching device that controls the flow of the air from the cooling unit to the storage unit by opening and closing;
a heating device that heats the storage section;
Furthermore,
The control unit is configured such that during execution of the high-temperature cooling control, the determination temperature rises above a center temperature of the second temperature zone to exceed a third threshold that is smaller than the first threshold, and exceeds the first threshold. If the temperature does not rise above the limit and the cooling section is stopped,
stopping the heating device, closing the switching device, and stopping the blower;
controlling the temperature of the storage section with a temperature lower than the center temperature of the second temperature zone by a predetermined maintenance threshold as a target temperature;
The refrigerator according to any one of claims 2 to 3. a blower that sends the air cooled by the cooling unit to the storage unit;
a switching device that controls the flow of the air from the cooling unit to the storage unit by opening and closing;
a heating device that heats the storage section;
Furthermore,
The control unit is configured such that during execution of the high-temperature cooling control, the determination temperature rises above a center temperature of the second temperature zone to exceed a third threshold that is smaller than the first threshold, and exceeds the first threshold. If the temperature does not rise above and the cooling section is operating,
stopping the heating device, opening the switching device, and starting the blower;
controlling the temperature of the storage section with a temperature lower than the center temperature of the second temperature zone by a predetermined maintenance threshold as a target temperature;
The refrigerator according to any one of claims 2 to 3. The control unit continues the high-temperature cooling control if the determined temperature does not rise by more than the third threshold value than the center temperature of the second temperature zone during execution of the high-temperature cooling control.
The refrigerator according to claim 4 or claim 5. a blower that sends the air cooled by the cooling unit to the storage unit;
a switching device that controls the flow of the air from the cooling unit to the storage unit by opening and closing;
a heating device that heats the storage section;
Furthermore,
The control unit is configured such that during execution of the low-temperature cooling control, the determination temperature rises above a center temperature of the first temperature zone to exceed a fourth threshold value that is smaller than the second threshold value, and the second threshold value is exceeded. If it does not rise above the limit and the cooling section is stopped,
stopping the heating device, closing the switching device, and stopping the blower;
controlling the temperature of the storage section with a temperature lower than the center temperature of the first temperature zone by a predetermined maintenance threshold as a target temperature;
The refrigerator according to claim 3. The control unit is configured such that during execution of the low-temperature cooling control, the determination temperature rises beyond a center temperature of the first temperature zone and exceeds a fifth threshold value that is larger than the fourth threshold value, and the cooling unit operates. If you are
stopping the heating device, opening the switching device, and starting the blower;
controlling the temperature of the storage unit by setting a temperature lower than the center temperature of the first temperature zone by the maintenance threshold value as a target temperature;
The refrigerator according to claim 7. The control unit determines that when the determination temperature rises from the center temperature of the first temperature zone by more than the fourth threshold value, does not rise more than the fifth threshold value, and the cooling part is operating. for,
stopping the heating device, closing the switching device, and starting the blower;
controlling the temperature by setting a temperature lower than the center temperature of the first temperature zone by the maintenance threshold value as a target temperature;
The refrigerator according to claim 8. The control unit continues the low-temperature cooling control if the determined temperature does not rise by more than the fourth threshold value than the center temperature of the first temperature zone during execution of the high-temperature cooling control.
The refrigerator according to any one of claims 7 to 9. The control unit calculates a maintenance time during which heat capacity can be reduced corresponding to the increase in heat capacity due to the increase in temperature due to opening and closing of the door, and sets the temperature lower by the maintenance threshold value by the maintenance time to a target temperature. to perform temperature control,
The refrigerator according to any one of claims 4, 5, 7, 8, and 9. The control unit executes a defrosting operation of the cooling unit when switching from the low-temperature cooling control to the high-temperature cooling control.
The refrigerator according to any one of claims 1 to 11.

Images