Refrigerator

Abstract

To provide a refrigerator that applies a temperature sensor near an evaporator to temperature control of a freezing chamber, and more appropriately performs the temperature control of the freezing chamber.SOLUTION: A refrigerator executes: control for driving a compressor and a cooling fan when the temperature of a second sensor exceeds a compressor ON temperature, and stopping the compressor and the cooling fan when it falls below a compressor OFF temperature; and control for opening a cooling damper when the compressor is driven, and the temperature of a first sensor exceeds a damper opening temperature, and closing the cooling damper when it falls below a damper closing temperature. If the cooling damper is not opened while the compressor is driven, the compressor OFF temperature is set to a first OFF temperature. If the cooling damper is opened while the compressor is driven, the compressor OFF temperature is set to a second OFF temperature set higher than the first OFF temperature.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to the technology of refrigerators.

Background Art

[0002] Conventionally, technologies related to ON / OFF control of compressors in refrigerators are known. For example, Japanese Patent Application Laid-Open No. 11-44474 (Patent Document 1) discloses a refrigerator and its control method. According to Patent Document 1, the temperature of the evaporator is detected, and based on the detected temperature, the operations of the compressor and the blower fan are controlled so that the indoor temperature of the freezer compartment is maintained within a predetermined range. Also, the damper is opened and closed so that the indoor temperature of the refrigerator compartment is maintained within a predetermined range. As a result, it is possible to control the temperatures of the freezer compartment and the refrigerator compartment with a small number of temperature sensors, and the manufacturing cost can be reduced.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the configuration disclosed in Patent Document 1, it has been found that it is not possible to cope with changes in the load inside the refrigerator due to the opening and closing of the damper, and in particular, there is a problem that the cooling of the freezer compartment cannot be properly performed. An object of the present invention is to provide a refrigerator that utilizes a temperature sensor near the evaporator for temperature control of the freezer compartment and performs more appropriate temperature control of the freezer compartment.

Means for Solving the Problems

[0005] According to an aspect of the present invention, there is provided a refrigerator including a refrigerating compartment, a freezing compartment, a compressor, an evaporator, a first sensor for measuring the temperature of the refrigerating compartment, a second sensor for measuring the temperature near the evaporator, a cooling fan for sending the cold air cooled by the evaporator to the freezing compartment, a refrigerating compartment cold air circuit for circulating a part of the cold air sent by the cooling fan to the refrigerating compartment, a cooling damper provided in the refrigerating compartment cold air circuit for opening and closing the refrigerating compartment cold air circuit, and a control unit. The control unit drives the compressor and the cooling fan when the temperature of the second sensor exceeds the compressor ON temperature, and stops the compressor and the cooling fan when the second sensor falls below the compressor OFF temperature. The control unit also executes control to open the cooling damper when the compressor is driven and the temperature of the first sensor exceeds the damper opening temperature, and to close the cooling damper when the temperature of the first sensor falls below the damper closing temperature. The compressor OFF temperature is switchable between a first OFF temperature and a second OFF temperature set higher than the first OFF temperature. When the cooling damper is not opened during the driving of the compressor, the compressor OFF temperature is set to the first OFF temperature, and when the cooling damper is opened during the driving of the compressor, the compressor OFF temperature is set to the second OFF temperature.

Advantages of the Invention

[0006] As described above, according to the present invention, there is provided a refrigerator that appropriately controls the temperature control of the freezing compartment by using a temperature sensor near the evaporator.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Mode for Carrying Out the Invention

[0008] Hereinafter, each embodiment of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed descriptions thereof will not be repeated. [First Embodiment] <Overall Configuration of Refrigerator>

[0009] First, with reference to FIGS. 1 and 2, the overall configuration of the refrigerator 100 according to the present embodiment will be described.

[0010] The refrigerator 100 is mainly composed of a heat-insulating box body 110. The storage space of the refrigerator 100 is formed by this heat-insulating box body 110. The storage space formed by the heat-insulating box body 110 is provided with a refrigerating chamber 111 at the upper part and a freezing chamber 112 at the lower part by, for example, a heat-insulating partition extending in the horizontal direction.

[0011] A refrigerating chamber door 111X is provided in the refrigerating chamber 111. A freezing chamber door 112X is also provided in the freezing chamber 112.

[0012] Regarding the refrigerator 100 according to the present embodiment, a cooling mechanism 129 such as an evaporator 124, a cooling fan 125, and a cooling damper 126 is arranged behind the freezing chamber 112 provided in the lower stage. Further, a compressor 121, a condenser (not shown), etc. are arranged outside the heat-insulating box body 110 such as a machine room 120, and an evaporator 124, a cooling fan 125, etc. are arranged in a cooling chamber 128 located inside the rear of the heat-insulating box body 110.

[0013] In addition, as will be described later, a control unit is provided inside the refrigerator 100. This control unit controls each unit of the refrigerator 100 such as the cooling mechanism 129. That is, by driving the compressor 121 by the control unit 130, the operation of the refrigeration cycle is started, and the refrigerant circulates through the cycle. The high-temperature and high-pressure refrigerant compressed by the compressor 121 is condensed while releasing heat in the condenser. Subsequently, the high-temperature refrigerant expands in the expander and becomes low-temperature, and is sent to the evaporator 124. The refrigerant flowing into the evaporator 124 becomes low-temperature by adiabatic expansion, exchanges heat with the air flowing through the cooling chamber 128, evaporates while absorbing heat, becomes a gaseous refrigerant, and is sent to the compressor 121.

[0014] In this way, by circulating the refrigerant and operating the refrigeration cycle, cold air exchanged with the evaporator 124 is generated.

[0015] As described above, the evaporator 124 is disposed in the cooling chamber 128 provided on the back side of the refrigerator 100. The cooling chamber 128 is disposed behind the freezer compartment 112. In addition to the evaporator 124, a cooling fan 125 is provided in the cooling chamber 128. The cooling fan 125 is provided to circulate air between the cooling chamber 128 and each storage space. That is, the cooling fan 125 sends the cold air generated by the evaporator 124 during the operation of the refrigeration cycle or the like to each storage space via the cold air circuit 127 such as the cooling damper 126 and the air outlets 111Y, 112Y, and returns the cold air supplied to each storage chamber to the cooling chamber 128 through the inlets 111Z, 112Z.

[0016] In the present embodiment, a cooling damper 126 is provided in the cold air circuit (refrigerator cold air circuit) between the cooling fan 125 and the air outlet 111Y to the refrigerator compartment 111, and the cooling damper 126 is opened according to an instruction from the control unit 130 when cold air is to be sent to the refrigerator compartment 111. Then, when cold air is not sent to the refrigerator compartment 111, that is, when cold air is sent only to the freezer compartment 112, the cooling damper 126 is closed according to an instruction from the control unit 130. <Functional Configuration of Refrigerator 100>

[0017] Next, with reference to FIG. 3, one aspect of the configuration of the refrigerator 100 will be described. The refrigerator 100 according to the present embodiment includes, as main components, a control unit 130, an operation unit 140, a cooling mechanism 129, a refrigerator compartment temperature sensor (first sensor) 181, and an evaporator temperature sensor (second sensor) 182.

[0018] The control unit 130 includes a CPU (Central Processing Unit) 131, a memory 132, a timer, various interfaces, and various circuits.

[0019] The CPU 131 executes various processes described later by executing the programs stored in the memory 132.

[0020] The memory 132 is realized by various RAMs, various ROMs, etc., and stores programs executed by the CPU 131, data generated by the execution of the programs by the CPU 131, data input via the operation unit 140, data received from a server via a router or the Internet, and various data for maintaining the refrigerator compartment 111 and the freezer compartment 112 at a predetermined temperature.

[0021] The operation unit 140 receives operations from the user and inputs them to the control unit 130.

[0022] The cooling mechanism 129 mainly includes a compressor 121, a condenser 122, a capillary tube 123, an evaporator 124, a cooling fan 125, a cooling damper 126, etc. The compressor 121 and the cooling fan 125 change ON / OFF and rotational speed according to instructions from the control unit 130. The cooling damper 126 performs an opening / closing operation according to instructions from the control unit 130.

[0023] The refrigerator compartment temperature sensor 181 measures the temperature inside the refrigerator compartment 111 and inputs the measurement result to the control unit 130.

[0024] The evaporator temperature sensor 182 is disposed near the evaporator 124, measures the temperature near the evaporator 124, and inputs the measurement result to the control unit 130. When moisture contained in the cold air flowing through the surface of the evaporator 124 adheres to the surface of the evaporator 124, it forms frost, and when this frost accumulates, the heat exchange efficiency of the evaporator 124 decreases. To remove this frost, a heater is installed in the cooling chamber 128, and the heater is controlled based on the temperature of the evaporator temperature sensor 182 to defrost the surface of the evaporator 124 while preventing the temperature of the cooling chamber 128 from rising too much.

[0025] In the present embodiment, although no temperature sensor is provided in the freezer compartment 112, the control unit 130 controls the ON / OFF of the compressor 121, the opening / closing operation of the cooling damper 126, etc. as follows based on the temperature near the evaporator 124 and the temperature of the refrigerator compartment 111. <Control of Damper and Compressor>

[0026] Referring to FIG. 4, in the present embodiment, the cooling damper is opened and closed based on the temperature of the refrigerator compartment 111. Usually, when the temperature TR of the refrigerator compartment 111 exceeds the damper opening temperature TDO (B, K in FIG. 4) based on the measurement value of the refrigerator compartment temperature sensor 181, the control unit 130 opens the cooling damper 126, and when the temperature TR of the refrigerator compartment 111 falls below the damper closing temperature TDC (C, G in FIG. 4), the control unit 130 closes the cooling damper 126. Thereby, the temperature in the refrigerator compartment 111 is controlled to be within a predetermined temperature range.

[0027] Then, the compressor 121 is turned ON / OFF based on the temperature near the evaporator 124. Usually, when the temperature TE of the evaporator 124 exceeds the compressor ON temperature TC1 (A, F, I, K in FIG. 4) based on the measurement value of the evaporator temperature sensor 182, the control unit 130 drives the compressor 121, and when the temperature TE of the evaporator 124 falls below the compressor OFF temperature TC0 (D, H, J in FIG. 4), the control unit 130 stops the compressor 121. Thereby, the temperature of the evaporator 124 is maintained within a predetermined temperature range, that is, between the compressor OFF temperature TC0 and the compressor ON temperature TC1.

[0028] Note that the cooling fan 125 also turns ON / OFF in accordance with the ON / OFF of the compressor 121. As a result, when the cooling damper 126 is closed and the compressor 121 is being driven, only the inside of the freezer compartment 112 is cooled. Also, when the cooling damper 126 is open and the compressor 121 is being driven, the freezer compartment 112 and the refrigerator compartment 111 are cooled.

[0029] And in the present embodiment, when the compressor 121 is OFF, the control unit 130 is programmed to close the cooling damper 126. However, when the compressor 121 is OFF and the temperature of the refrigerator compartment 111 exceeds the damper opening temperature TDO (E and K in FIG. 4), the control unit 130 changes the compressor ON temperature TC1 to be several degrees lower than normal. This makes it easier to drive the compressor 121 earlier, and as a result, the control unit 130 can open the cooling damper 126 earlier so that the temperature of the refrigerator compartment 111 does not rise too much.

[0030] Also, particularly in the present embodiment, when the compressor 121 is ON, until the cooling damper 126 is opened, the control unit 130 changes the compressor OFF temperature TC0 to be several degrees lower than normal (between A - B and between I - J in FIG. 4).

[0031] In a state where the cooling damper 126 is closed and only the inside of the freezer compartment 112 is cooled, the cold air returning to the cooling chamber 128 is supplied only from the suction port 112Z of the freezer compartment 112, and the temperature of the evaporator 124 often drops rapidly. And the cooling chamber 128 where the evaporator temperature sensor 182 is disposed is partitioned from the freezer compartment 112, and is more susceptible to the temperature of the evaporator 124 than the temperature inside the freezer compartment 112. Therefore, there was a problem that before the temperature inside the freezer compartment 112 sufficiently dropped, the detected temperature of the evaporator temperature sensor 182 reached the compressor OFF temperature TC0, causing the compressor 121 to stop.

[0032] In this embodiment, in order to solve this problem, when the cooling damper 126 is closed and only the inside of the freezer compartment 112 is cooled, the compressor OFF temperature TC0 is set several degrees lower than normal. As a result, even though the temperature of the freezer compartment 112 has not dropped, the temperature near the evaporator 124 is low, so the possibility of the compressor 121 being turned off can be reduced.

[0033] Note that when the cooling damper 126 opens, in addition to the freezer compartment 112, the refrigerator compartment 111 is also cooled. In this case, since the cold air returning to the cooling chamber 128 is also supplied from the suction port 111Z of the refrigerator compartment 111, the temperature of the evaporator 124 is less likely to drop compared to the state where only the inside of the freezer compartment 112 is cooled, and the deviation between the temperature inside the freezer compartment 112 and the detected temperature of the evaporator temperature sensor 182 is reduced.

[0034] Therefore, in this embodiment, when the compressor 121 is ON and a state occurs where the cooling damper 126 opens and the freezer compartment 112 and the refrigerator compartment 111 are cooled, the compressor OFF temperature TC0 is returned to the normal set value. Thereby, overcooling of the freezer compartment 112 can be prevented.

[0035] Note that while the compressor 121 is ON, the temperature of the refrigerator compartment 111 may reach the damper closing temperature TDC and the cooling damper 126 may be closed (C, G in FIG. 4). In this case, the compressor OFF temperature TC0 is kept at the normal set value without being set low. Since the deviation between the temperature inside the freezer compartment 112 and the detected temperature of the evaporator temperature sensor 182 is reduced when the cooling damper 126 opens, insufficient cooling of the freezer compartment 112 is unlikely to occur even if the cooling damper 126 is closed thereafter. <Processing by the control unit 130>

[0036] The CPU 131 of the control unit 130 executes the following processes according to the programs and data in the memory 132. In the memory 132, the damper opening temperature TDO and the damper closing temperature TDC are stored. As an example, TDO = 6°C and TDC = 1°C. Also, in the memory 132, two set values TC1A and TC1B are stored as the compressor ON temperature TC1. Also, two set values TC0A and TC0B are stored as the compressor OFF temperature TC0. TC1B is set to a lower temperature than TC1A. Also, TC0B is set to a lower temperature than TC0A. Note that the relationship TC1 > TC0 always holds for the set values of the compressor ON temperature TC1 and the compressor OFF temperature TC0.

[0037] As an example, TC1A = -16°C, TC1B = -18°C, TC0A = -21°C, and TC0B = -24°C. Assume that in the initial state, TC1B is set for the compressor ON temperature TC1 and TC0A is set for the compressor OFF temperature TC0.

[0038] Referring to FIG. 5, first, the CPU 131 determines whether the temperature TE of the evaporator 124 is equal to or higher than the compressor ON temperature TC1 (step S102).

[0039] When the temperature TE of the evaporator 124 is equal to or higher than the compressor ON temperature TC1 (YES in step S102), the CPU 131 turns on the compressor 121 and turns on the cooling fan 125 (step S104). At this time, the CPU 131 sets the compressor ON temperature TC1 to TC1A. Also, the CPU 131 sets the compressor OFF temperature TC0 to TC0B.

[0040] The CPU 131 determines whether the temperature TR of the refrigerating chamber is equal to or higher than the damper opening temperature TDO (step S112). When the refrigerating chamber temperature TR is equal to or higher than the damper opening temperature TDO (YES in step S112), the CPU 131 opens the cooling damper 126 and changes the compressor OFF temperature TC0 to TC0A (step S114).

[0041] The CPU 131 determines whether the temperature TR of the refrigerating chamber 111 is less than or equal to the damper closing temperature TDC (step S116).

[0042] When the temperature TR of the refrigerating chamber 111 is less than or equal to the damper closing temperature TDC (YES in step S116), the CPU 131 closes the cooling damper 126 (step S120). The CPU 131 determines whether the temperature TE of the evaporator 124 is less than or equal to the compressor OFF temperature TC0 (step S122).

[0043] In addition, when the refrigerating chamber temperature TR is not greater than the damper opening temperature TDO (NO in step S112), the CPU 131 also determines whether the temperature TE of the evaporator 124 is less than or equal to the compressor OFF temperature TC0 (step S122).

[0044] When the temperature TE of the evaporator 124 is less than or equal to the compressor OFF temperature TC0 (YES in step S122), the CPU 131 turns off the compressor 121 and turns off the cooling fan 125 (step S124). At this time, the CPU 131 sets the compressor ON temperature TC1 to TC1A. Also, the CPU 131 sets the compressor OFF temperature TC0 to TC0A.

[0045] The CPU 131 determines whether the temperature TR of the refrigerating chamber 111 is greater than or equal to the damper opening temperature TDO (step S132). When the temperature TR of the refrigerating chamber 111 is greater than or equal to the damper opening temperature TDO (YES in step S132), the CPU 131 changes the compressor ON temperature TC1 to TC1B (step S134).

[0046] The CPU 131 determines whether the temperature TE of the evaporator 124 is equal to or higher than the compressor ON temperature TC1 (step S138). When the temperature TE of the evaporator 124 is equal to or higher than the compressor ON temperature TC1 (YES in step S138), the CPU 131 turns on the compressor 121 and turns on the cooling fan 125 (returns to step S104). When the temperature TE of the evaporator 124 is not equal to or higher than the compressor ON temperature TC1 (NO in step S138), the process from step S132 is repeated. [Second Embodiment]

[0047] Also, when the compressor 121 is switched from OFF to ON, it is preferable to lower the compressor OFF temperature TC0 (set to TC0B). When the compressor 121 is switched from ON to OFF, it is preferable to return the compressor OFF temperature TC0 to the normal set value (TC0A). [Third Embodiment]

[0048] In addition to the above embodiments, when the time during which the compressor 121 has been OFF before it is turned ON is long, it is preferable that the control unit 130 does not perform the correction of lowering the compressor OFF temperature TC0 as described above. More specifically, when the time during which the compressor 121 has been OFF immediately before it is turned ON is equal to or longer than a first predetermined time, for example, 30 minutes or more, the control unit 130 does not perform the correction of lowering the compressor OFF temperature TC0 as described above until the time during which the compressor 121 has been OFF becomes equal to or shorter than a second predetermined time, for example, 20 minutes or less.

[0049] When the compressor 121 has been off for a long time, it is considered that the contents in the freezer compartment 112 are sufficiently cooled and the cooling load has become light. Therefore, it is considered that the deviation between the temperature in the freezer compartment 112 and the detected temperature of the evaporator temperature sensor 182 is small. Thus, until the time that the compressor 121 has been off is equal to or less than the second predetermined time, that is, until the cooling load of the contents in the freezer compartment 112 increases again, it is unlikely that there will be insufficient cooling of the freezer compartment 112 even if the compressor-off temperature TC0 is not lowered. Thereby, overcooling of the freezer compartment 112 can be prevented. [Fourth Embodiment]

[0050] Alternatively, when the detected temperature of the evaporator temperature sensor 182 reaches the compressor-off temperature TC0 without the cooling damper 126 opening, the control unit 130 may set a delay time until turning off the compressor 121. That is, even when the temperature of the evaporator 124 for turning off the compressor 121 is reached, the control unit 130 may continue to drive the compressor 121 until the delay time has elapsed. Thereby, insufficient cooling of the freezer compartment 112 can be solved. [Summary]

[0051] In the above embodiment, there is provided a refrigerator including a refrigerating compartment, a freezing compartment, a compressor, an evaporator, a first sensor for measuring the temperature of the refrigerating compartment, a second sensor for measuring the temperature near the evaporator, a cooling fan for sending the cold air cooled by the evaporator to the freezing compartment, a refrigerating compartment cold air circuit for allowing a part of the cold air sent by the cooling fan to flow into the refrigerating compartment, a cooling damper provided in the refrigerating compartment cold air circuit for opening and closing the refrigerating compartment cold air circuit, and a control unit. The control unit drives the compressor and the cooling fan when the temperature of the second sensor exceeds the compressor ON temperature, and stops the compressor and the cooling fan when the second sensor drops below the compressor OFF temperature. The control unit also executes control to open the cooling damper when the compressor is driven and the temperature of the first sensor exceeds the damper opening temperature, and to close the cooling damper when the temperature of the first sensor drops below the damper closing temperature. The compressor OFF temperature can be switched between a first OFF temperature and a second OFF temperature set higher than the first OFF temperature. When the cooling damper is not opened during the driving of the compressor, the compressor OFF temperature is set to the first OFF temperature, and when the cooling damper is opened during the driving of the compressor, the compressor OFF temperature is set to the second OFF temperature.

[0052] Preferably, the compressor ON temperature can be switched between a first ON temperature and a second ON temperature set lower than the first ON temperature. The control unit sets the compressor ON temperature to the first ON temperature when the temperature of the first sensor is below or equal to the damper opening temperature during the stop of the compressor, and sets the compressor ON temperature to the second ON temperature when the temperature of the first sensor exceeds the damper opening temperature during the stop of the compressor.

[0053] Preferably, when the time during which the compressor has been stopped before driving the compressor is longer than a predetermined time, the control unit sets the compressor OFF temperature to the second OFF temperature regardless of the control of the cooling damper.

[0054] The embodiments disclosed this time should be considered as illustrative in all respects and not restrictive. The scope of the present invention is shown not by the above description but by the claims, and it is intended that all modifications within the meaning and scope equivalent to the claims are included. Also, configurations obtained by combining the configurations of different embodiments described in this specification with each other are included in the scope of the present invention.

Explanation of Signs

[0055] 100: Refrigerator 110: Heat-insulating box body 111: Refrigerating compartment 111X: Door of the refrigerating compartment 112: Freezing compartment 112X: Door of the freezing compartment 120: Machine room 121: Compressor 122: Condenser 123: Capillary tube 124: Evaporator 125: Cooling fan 126: Cooling damper 127: Refrigerating circuit 128: Cooling chamber 129: Cooling mechanism 130: Control unit 131: CPU 132: Memory 140: Operation unit 181: Refrigerating compartment temperature sensor 182: Evaporator temperature sensor

Claims

1. A refrigerator compartment, a freezer compartment, a compressor, an evaporator, a first sensor for measuring the temperature of the refrigerator compartment, a second sensor for measuring the temperature near the evaporator, a cooling fan for sending the cold air cooled by the evaporator to the freezer compartment, a refrigerator compartment cold air circuit through which a part of the cold air sent by the cooling fan flows into the refrigerator compartment, a cooling damper provided in the refrigerator compartment cold air circuit for opening and closing the refrigerator compartment cold air circuit, and a control unit, wherein the control unit drives the compressor and the cooling fan when the temperature of the second sensor exceeds the compressor ON temperature, and stops the compressor and the cooling fan when the second sensor drops below the compressor OFF temperature; and when the compressor is driven and the temperature of the first sensor exceeds the damper open temperature, the control unit opens the cooling damper, and when the temperature of the first sensor drops below the damper closed temperature, the control unit closes the cooling damper. The refrigerator wherein the compressor OFF temperature is switchable between a first OFF temperature and a second OFF temperature set higher than the first OFF temperature, and when the cooling damper is not opened during the driving of the compressor, the compressor OFF temperature is set to the first OFF temperature, and when the cooling damper is opened during the driving of the compressor, the compressor OFF temperature is set to the second OFF temperature.

2. The compressor ON temperature is switchable between a first ON temperature and a second ON temperature set lower than the first ON temperature, wherein the control unit sets the compressor ON temperature to the first ON temperature when the temperature of the first sensor is below the damper open temperature during the stop of the compressor, and sets the compressor ON temperature to the second ON temperature when the temperature of the first sensor exceeds the damper open temperature during the stop of the compressor. The refrigerator according to claim 1.

3. The control unit sets the compressor OFF temperature to the second OFF temperature regardless of the control of the cooling damper when the time during which the compressor has been stopped before the driving of the compressor is longer than a predetermined time. The refrigerator according to claim 1 or 2.

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