CN111801539B

CN111801539B - Refrigerator and control method thereof

Info

Publication number: CN111801539B
Application number: CN201980016711.9A
Authority: CN
Inventors: 崔相福; 金成昱; 朴景培; 池成
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 2018-03-08
Filing date: 2019-01-31
Publication date: 2022-04-26
Anticipated expiration: 2039-01-31
Also published as: AU2019232055A1; AU2019232055B2; US20210055034A1; CN114704994A; KR102614564B1; CN111801539A; CN114704994B; WO2019172532A1; EP3764033A1; EP3764033A4; KR20190106242A

Abstract

A method of controlling a refrigerator according to an embodiment of the present invention includes: a heating element of the sensor responsive to the change in air flow is turned on for a predetermined period of time and then turned off; sensing a first sensed temperature (Ht1) of the heating element in a state in which the heating element is open, and sensing a second sensed temperature (Ht2) of the heating element in a state in which the heating element is closed; and sensing an amount of frost on an evaporator based on a temperature difference between the first sensed temperature (Ht1) and the second sensed temperature (Ht 2).

Description

Refrigerator and control method thereof

Technical Field

The present disclosure relates to a refrigerator and a control method thereof.

Background

A refrigerator is a home appliance capable of storing articles such as food in a storage chamber provided in a cabinet at a low temperature. Since the storage space is surrounded by the heat insulating wall, the inside of the storage space can be maintained at a temperature less than the outside temperature.

The storage space may be divided into a refrigerating storage space or a freezing storage space according to a temperature range of the storage space.

The refrigerator may further include an evaporator for supplying cool air to the storage space. The air in the storage space is cooled while flowing to the space where the evaporator is disposed, thereby exchanging heat with the evaporator, and the cooled air is supplied to the storage space again.

Here, if the air heat-exchanged with the evaporator contains moisture, the moisture freezes on the surface of the evaporator when the air heat-exchanges with the evaporator, thereby generating frost on the surface of the evaporator.

Since the flow resistance of the air acts on the frost, the more the amount of increase of the frost frozen on the evaporator surface increases, the more the flow resistance increases. As a result, heat exchange efficiency of the evaporator may be deteriorated, and thus power consumption may be increased.

Therefore, the refrigerator further includes a defroster for removing frost on the evaporator.

Korean patent laid-open publication No. 2000-0004806 (prior art document) discloses a variable defrosting cycle method.

In the prior art document, the cumulative operating time and the external temperature of the compressor are used to adjust the defrost cycle.

However, like the prior art document, when the defrosting period is determined using only the accumulated operating time of the compressor and the external temperature, the amount of frost on the evaporator (hereinafter, referred to as a frost generating amount) is not reflected. Therefore, it is difficult to accurately determine the time point at which defrosting is required.

That is, the frost generation amount may be increased or decreased according to various environments such as a user's refrigerator use mode and a degree to which air retains moisture. In the case of the prior art document, there is a disadvantage in that the defrosting cycle is determined without reflecting various environments.

Further, in the case of the prior art document, there is a disadvantage in that it is difficult to identify an exact defrosting time point since it is possible to detect a local frost amount of the evaporator and it is difficult to detect a frost amount on the entire evaporator.

Therefore, there are disadvantages in that: although a large amount of frost is generated and defrosting is not started, cooling performance is deteriorated; or starts defrosting although the amount of frost generated is low, thereby increasing power consumption due to unnecessary defrosting.

Disclosure of Invention

Technical problem

An object of the present disclosure is to provide a refrigerator and a control method thereof, which determine a time point for a defrosting operation using a parameter that varies depending on an amount of frost on an evaporator.

Further, it is an object of the present disclosure to provide a refrigerator and a control method thereof, which accurately determine a point of time at which defrosting is required according to an amount of frost on an evaporator using a sensor having an output value that is changed depending on an air flow rate.

Further, another object of the present disclosure is to provide a refrigerator and a control method thereof, which can accurately determine a time point of defrosting even in a case where the accuracy of a sensor for determining the time point of defrosting is low.

Further, it is still another object of the present disclosure to provide a refrigerator and a control method thereof, in which a detection logic for detecting an amount of frost on an evaporator can be performed at an appropriate point of time.

Further, it is still another object of the present disclosure to provide a refrigerator and a control method thereof, which improve reliability in consideration of a change of an external environment in detecting an amount of frost on an evaporator.

Technical scheme

In order to solve the above-mentioned problems, a control method of a refrigerator includes detecting an amount of frost on an evaporator based on a temperature difference between a first detected temperature (Ht1) of a heat generating element of a sensor that is detected in a state where the heat generating element is turned on and a second detected temperature (Ht2) of the heat generating element that is detected in a state where the heat generating element is turned off, the sensor being responsive to a change in an air flow rate.

As an embodiment, the first detected temperature (Ht1) may be a temperature detected by a sensing element of the sensor immediately after the heating element is turned on, and the second detected temperature (Ht2) may be a temperature detected by the sensing element of the sensor immediately after the heating element is turned off.

As an embodiment, the first detected temperature (Ht1) may be a lowest temperature value during a period in which the heat generating element is turned on, and the second detected temperature (Ht2) may be a highest temperature value after the heat generating element is turned off.

Further, when the storage compartment of the refrigerator is being cooled, the heat generating element may be in an open state. As an embodiment, the heat generating element may be in an on state while driving the blower for cooling the storage compartment.

The control method of the present disclosure may further include: determining whether a temperature difference between the first detected temperature (Ht1) and the second detected temperature (Ht2) is less than a first reference difference; and performing a defrosting operation of removing frost generated on a surface of the evaporator when it is determined that a temperature difference between the first detected temperature (Ht1) and the second detected temperature (Ht2) is less than a first reference difference.

The control method of the present disclosure may further include: when the heating element is turned on for the predetermined period of time and then turned off, it is determined whether a temperature difference between the first detected temperature (Ht1) and the second detected temperature (Ht2) is less than a second reference difference value, and the heating element may be turned on when the temperature difference between the first detected temperature (Ht1) and the second detected temperature (Ht2) is less than the second reference difference value.

Opening the heat generating element based on an accumulated cooling operation time of the storage compartment when the temperature difference between the first detected temperature (Ht1) and the second detected temperature (Ht2) is less than the second reference difference value.

In order to solve the above problems, a method of controlling a refrigerator includes: the amount of frost on the evaporator is detected based on a temperature difference between a first detected temperature (Ht1) which is the lowest value and a second detected temperature (Ht2) which is the highest value among the detected temperatures of the heat generating elements.

Further, when the storage compartment of the refrigerator is being cooled, the heat generating element may be in an open state. As an embodiment, the heat generating element may be in an open state while driving the fan for cooling the storage compartment.

The control method of the refrigerator may further include: determining whether a temperature difference between the first detected temperature (Ht1) and a second detected temperature (Ht2) is less than a first reference difference value; and performing a defrosting operation of removing frost generated on a surface of the evaporator when it is determined that a temperature difference between the first detected temperature (Ht1) and the second detected temperature (Ht2) is less than a first reference difference.

In order to solve the above problems, a refrigerator may include: a heating element; a sensor including a sensing element that detects a temperature of the heat generating element; and a controller that detects an amount of frost on the evaporator based on a temperature difference between a first detected temperature (Ht1) of the heat generating element detected in a state where the heat generating element is turned on and a second detected temperature (Ht2) of the heat generating element detected in a state where the heat generating element is turned off.

Advantageous effects

According to the proposed invention, since the point of time at which defrosting is required is determined using the sensor having the output value changed according to the amount of frost generated on the evaporator in the bypass passage, the point of time at which defrosting is required can be accurately determined.

Further, even in the case where the accuracy of the sensor for determining the time point of defrosting is low, the time point of defrosting can be accurately determined, thereby significantly reducing the cost of the sensor.

Further, since the detection logic for detecting the amount of frost on the evaporator can be performed at an appropriate point in time, power consumption is reduced and convenience is improved.

In addition, since a change in an external environment (e.g., an internal refrigerator load) is taken into consideration in detecting the amount of frost on the evaporator, product reliability is improved.

Drawings

Fig. 1 is a schematic longitudinal sectional view of a refrigerator according to one embodiment of the present invention.

Fig. 2 is a perspective view of a cool air duct according to an embodiment of the present invention.

Fig. 3 is an exploded perspective view illustrating a state in which a channel cover and a sensor are separated from each other in a cool air duct.

Fig. 4 is a view illustrating air flows in the heat exchange space and the bypass passage before and after frost is generated.

Fig. 5 is a schematic view showing a state in which the sensor is arranged in the bypass passage.

FIG. 6 is a view of a sensor according to an embodiment of the present invention.

Fig. 7 is a view showing heat flow around the sensor depending on the air flow flowing through the bypass passage.

Fig. 8 is a control block diagram of a refrigerator according to one embodiment of the present disclosure.

Fig. 9 is a flowchart illustrating a control method for detecting the amount of frost on an evaporator according to one embodiment of the present disclosure.

Fig. 10 is a flowchart illustrating a method of performing a defrosting operation by determining a time point at which a refrigerator needs to be defrosted according to an embodiment of the present disclosure.

Fig. 11 is a view illustrating a temperature change of a heat generating element according to turning on/off of the heat generating element before and after frost is formed on an evaporator according to an embodiment of the present disclosure.

Fig. 12 is a flowchart illustrating a control method for determining an operation time point of a heat generating element according to one embodiment of the present disclosure.

Detailed Description

Hereinafter, some embodiments of the present invention will be described in detail with reference to the accompanying drawings. Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Note that, even if the same or similar components in the drawings are shown in different drawings, the same reference numerals are used to designate the components as much as possible. Further, in the description of the embodiments of the present disclosure, when it is determined that a detailed description of a well-known configuration or function interferes with understanding of the embodiments of the present disclosure, the detailed description will be omitted.

Further, in the description of the embodiments of the present disclosure, terms such as first, second, A, B, (a) and (b) may be used. Each term is used only to distinguish the corresponding component from other components and does not define the nature, order, or sequence of the corresponding components. It will be understood that when an element is "connected," "coupled," or "engaged" to another element, the former may be directly connected or engaged to the latter, or the latter may be "connected," "coupled," or "engaged" to the other element with a third element interposed therebetween.

Fig. 1 is a schematic longitudinal sectional view of a refrigerator according to one embodiment of the present invention, fig. 2 is a perspective view of a cool air duct according to one embodiment of the present invention, and fig. 3 is an exploded perspective view illustrating a state in which a channel cover and a sensor are separated from each other in the cool air duct.

Referring to fig. 1 to 3, a refrigerator 1 according to one embodiment of the present invention may include an inner case 12 defining a storage space 11.

The storage space may include one or more of a refrigerated storage space and a frozen storage space.

The cool air duct 20 provides a passage in the rear space of the storage space 11 through which cool air supplied to the storage space 11 flows. Further, the evaporator 30 is disposed between the cool air duct 20 and the rear wall 13 of the inner case 12. That is, a heat exchange space 222 in which the evaporator 30 is disposed is defined between the cool air duct 20 and the rear wall 13.

Accordingly, the air of the storage space 11 may flow to the heat exchange space 222 between the cold air duct 20 and the rear wall 13 of the inner case 12 and then exchange heat with the evaporator 30. After that, the air may flow through the inside of the cool air duct 20 and then be supplied to the storage space 11.

The cool air duct 20 may include, but is not limited to, a first duct 210 and a second duct 220, the second duct 220 being coupled to a rear surface of the first duct 210.

The front surface of the first duct 210 is a surface facing the storage space 11, and the rear surface of the first duct 210 is a surface facing the rear wall 13 of the inner case 12.

In a state where the first duct 210 and the second duct 220 are coupled to each other, a cool air passage 212 may be provided between the first duct 210 and the second duct 220.

In addition, the second duct 220 may have a cool air inflow hole 221 defined therein, and the first duct 210 may have a cool air discharge hole 211 defined therein.

A blower (not shown) may be provided in the cool air passage 212. Accordingly, when the blower fan rotates, air passing through the evaporator 13 is introduced into the cold air channel 212 through the cold air inflow hole 221 and discharged to the storage space 11 through the cold air discharge hole 211.

The evaporator 30 is disposed between the cool air duct 20 and the rear wall 13. Here, the evaporator 30 may be disposed below the cool air inflow hole 221.

Accordingly, the air in the storage space 11 ascends to exchange heat with the evaporator 30 and then is introduced into the cold air inflow hole 221.

According to this arrangement, when the amount of frost generated on the evaporator 30 increases, the amount of air passing through the evaporator 30 may be reduced, thereby deteriorating the heat exchange efficiency.

In this embodiment, a parameter that varies according to the amount of frost generated on the evaporator 30 may be used to determine a point in time at which defrosting of the evaporator 30 is required.

For example, the cold air duct 20 may further include a frost generation sensing portion configured to bypass at least a portion of the air flowing through the heat exchange space 222 and to determine a time point at which defrosting is required by using a sensor having different outputs according to an air flow rate.

The frost generating sensing part may include: a bypass passage 230 bypassing at least a portion of the air flowing through the heat exchange space 222; and a sensor 270 disposed in the bypass passage 230.

Although not limited, the bypass passage 230 may be provided in the first duct 210 in a concave shape. Alternatively, the bypass passage 230 may be provided in the second duct 220.

The bypass passage 230 may be provided by recessing a portion of the first duct 210 or the second duct 220 in a direction away from the evaporator 30.

The bypass passage 230 may extend in a vertical direction from the cool air duct 20.

The bypass passage 230 may be disposed to face the evaporator 30 within the left and right width of the evaporator 30 such that the air in the heat exchange space 222 is bypassed to the bypass passage 230.

The frost generating sensing portion may further include a passage cover 260, the passage cover 260 allowing the bypass passage 230 to be separated from the heat exchange space 222.

The duct cover 260 may be coupled to the cool air duct 20 to cover at least a portion of the vertically extending bypass duct 230.

The access cover 260 may include: a cover plate 261; an upper extension portion 262 extending upward from the cover plate 261; and a blocking portion 263 disposed under the cover plate 261.

Fig. 4 (a) shows the flow of air before frost is generated, and fig. 4 (b) shows the flow of air after frost is generated. In the present embodiment, as an example, a state after completion of the defrosting operation is assumed as a state before frost is generated.

First, referring to (a) of fig. 4, in the case where there is no frost on the evaporator 30 or the amount of generated frost is very small, most of the air passes through the evaporator 30 in the heat exchange space 222 (see arrow a). On the other hand, some air may flow through the bypass passage 230 (see arrow B).

Referring to (b) of fig. 4, when the amount of frost generated on the evaporator 30 is large (when defrosting is required), the amount of air flowing through the heat exchange space 222 may be reduced (see arrow C) and the amount of air flowing through the bypass passage 230 may be increased (see arrow D) because the frost of the evaporator 30 acts as a flow resistance.

As described above, the amount (or flow rate) of air flowing through the bypass passage 230 is changed according to the amount of frost generated on the evaporator 30.

In this embodiment, the sensor 270 may have an output value that varies according to a change in the flow rate of air flowing through the bypass passage 230. Therefore, whether defrosting is required can be determined based on the change in the output value.

Hereinafter, the structure and principle of the sensor 270 will be described.

Fig. 5 is a schematic view showing a state in which a sensor is disposed in a bypass passage, fig. 6 is a view of the sensor according to one embodiment of the present invention, and fig. 7 is a view showing heat flow around the sensor depending on air flow flowing through the bypass passage.

Referring to fig. 5-7, the sensor 270 may be disposed at a point in the bypass passage 230. Accordingly, the sensor 270 may contact the air flowing along the bypass passage 230, and an output value of the sensor 270 may be changed in response to a change in the air flow rate.

The sensor 270 may be disposed at a position spaced apart from each of the inlet 231 and the outlet 232 of the bypass passage 230. For example, the sensor 270 may be located in a central portion of the bypass passage 230.

Since the sensor 270 is disposed on the bypass passage 230, the sensor 270 may face the evaporator 30 within the left-right width range of the evaporator 30.

The sensor 270 may be, for example, a temperature sensor of the generated heat. In particular, the sensor 270 may include a sensor PCB 271, a heating element 273 mounted on the sensor PCB 271, and a sensing element 274 mounted on the sensor PCB 271 to sense the temperature of the heating element 273.

The heating element 273 may be a resistor that generates heat when current is applied.

The sensing element 274 may sense the temperature of the heating element 273.

When the flow rate of the air flowing through the bypass passage 230 is low, the temperature sensed by the sensing element 274 is high because the cooling amount of the heat generating element 273 by the air is small.

On the other hand, if the flow rate of the air flowing through the bypass passage 230 is large, the temperature sensed by the sensing element 274 decreases because the cooling amount of the heat generating element 273 by the air flowing through the bypass passage 230 increases.

The sensor PCB 271 may determine a difference between the temperature sensed by the sensing element 274 in a state where the heating element 273 is turned off and the temperature sensed by the sensing element 274 in a state where the heating element 273 is turned on.

The sensor PCB 271 may determine whether a difference between the states of the heating element 273 being turned on/off is less than a reference difference.

For example, referring to fig. 4 and 7, when the amount of frost generated on the evaporator 30 is small, the flow rate of air flowing to the bypass passage 230 is small. In this case, the heat flow of the heating element 273 is small, and the amount of cooling of the heating element 273 by the air is small.

On the other hand, when the amount of frost generated on the evaporator 30 is large, the flow rate of air flowing to the bypass passage 230 is large. Thus, the heat flow and cooling amount of the heating element 273 is large by the air flowing along the bypass passage 230.

Therefore, the temperature sensed by the sensing element 274 when the amount of frost generated on the evaporator 30 is large is smaller than the temperature sensed by the sensing element 274 when the amount of frost generated on the evaporator 30 is small.

Therefore, in the present embodiment, when the difference between the temperature sensed by the sensing element 274 in the state where the heating element 273 is turned on and the temperature sensed by the sensing element 274 in the state where the heating element 273 is turned off is less than the reference temperature difference, it can be determined that defrosting is required.

According to this embodiment, the sensor 270 may sense a temperature change of the heating element 273, the temperature of the heating element 273 being changed according to the flow rate of air changed according to the amount of frost generated to accurately determine the point of time at which defrosting is required according to the amount of frost generated on the evaporator 30.

The sensor 270 may also be provided with a sensor housing 272 such that air flowing through the bypass passage 230 is prevented from directly contacting the sensor PCB 271, the heat generating element 273, and the temperature sensor 274. In a state where the sensor case 272 is opened at one side, an electric wire connected to the sensor PCB 271 may be drawn out, and then the opened portion may be covered by the cover.

The sensor housing 271 may surround the sensor PCB 271, the heating element 273, and the temperature sensor 274.

Referring to fig. 8, a refrigerator 1 according to one embodiment of the present disclosure may include: the above-mentioned sensor 270; a defrosting device 50 operating to defrost the evaporator 30; a compressor 60 for compressing a refrigerant; a blower 70 for generating an air flow; and a controller 40 for controlling the sensor 270, the defroster 50, the compressor 60, and the blower 70.

The defrosting device 50 may include, for example, a heater. When the heater is turned on, heat generated by the heater is transferred to the evaporator 30 to melt frost generated on the surface of the evaporator 30. The heater may be connected to one side of the evaporator 30, or may be disposed to be spaced apart from a position adjacent to the heater 30.

The compressor 60 is a device for compressing a low-temperature and low-pressure refrigerant into a supersaturated gaseous refrigerant of high-temperature and high-pressure. Specifically, the high-temperature high-pressure supersaturated gaseous refrigerant compressed in the compressor 60 flows into a condenser (not shown). The refrigerant is condensed into a high-temperature high-pressure saturated liquid refrigerant, and the condensed high-temperature high-pressure saturated liquid refrigerant is introduced into an expander (not shown) and expanded into a low-temperature low-pressure two-phase refrigerant.

Further, the low-temperature and low-pressure two-phase refrigerant is evaporated into a low-temperature and low-pressure gaseous refrigerant while passing through the evaporator 30. In this process, the refrigerant flowing through the evaporator 30 may exchange heat with the external air (i.e., the air flowing through the heat exchange space 222), thereby achieving air cooling.

The blower 70 is disposed in the cool air passage 212 to generate an air flow. Specifically, when the blower fan 70 rotates, the air passing through the evaporator 30 flows into the cold air passage 212 via the cold air inflow hole 221 and is then discharged to the storage compartment 11 via the cold air discharge hole 211.

The controller 40 may control the heating element 273 of the sensor 270 to be turned on at regular periods.

To determine when defrosting is required, the heating element 273 may be maintained in an on state for a predetermined period of time, and the temperature of the heating element 273 may be detected by the sensing element 274.

After the heating element 273 is turned on for a predetermined period of time, the heating element 273 is turned off, and the sensing element 274 may detect the temperature of the turned-off heating element 273. In addition, the sensor PCB 271 may determine whether the maximum value of the temperature difference between the open/close states of the heating element 273 is equal to or less than a reference difference value.

Further, when the maximum value of the temperature difference between the on/off states of the heating element 273 is equal to or less than the reference difference value, it is determined that defrosting is required, and the controller 40 may turn on the defrosting device 50.

Although it has been described above that the sensor PCB 271 determines whether the temperature difference between the open/close states of the heating element 273 is equal to or less than the reference difference value, alternatively, the controller 40 may determine whether the temperature difference between the open/close states of the heating element 273 is equal to or less than the reference difference value and control the defroster 50 according to the determination result. That is, the sensor PCB 271 and the controller 40 may be electrically connected to each other.

Hereinafter, a method for detecting the amount of frost on the evaporator 30 using the heating element 273 will be described in detail with reference to the accompanying drawings.

Fig. 9 is a flowchart illustrating a control method for detecting the amount of frost on an evaporator according to one embodiment of the present disclosure. In the present embodiment, a method for detecting the amount of frost on the evaporator 30 in a state where the storage chamber 11 (e.g., a freezing chamber) is subjected to a cooling operation.

Referring to fig. 9, in step S11, the heating element 273 is turned on.

Specifically, the heating element 273 may be turned on in a state where a cooling operation of the storage compartment 11 (e.g., a freezing compartment) is performed.

Here, the state in which the cooling operation of the freezing chamber is performed may refer to a state in which the compressor 60 and the blower fan 70 are driven.

As described above, when the variation in the flow rate of air increases with the amount of frost on the evaporator 30, the detection accuracy of the sensor 270 can be improved. That is, when the change in the flow rate of air is large according to the amount of frost on the evaporator 30, the amount of change in the temperature detected by the sensor 270 becomes large, and thus the point in time at which defrosting is required can be accurately determined.

Therefore, the accuracy of the sensor can be improved only when frost on the evaporator 30 is detected in a state where an air flow occurs (i.e., in a state where the blower 70 is driven).

Next, in step S13, when the heater element 273 is turned on, the temperature of the heater element 273 is detected.

Specifically, the heating element 273 may be turned on for a predetermined period of time, and the temperature of the heating element 273 may be detected by the sensing element at a specific point of time in a state where the heating element 273 is turned on (Ht 1).

As the period of time for which the heating element 273 is turned on increases, the temperature of the heating element 273 may gradually increase. Further, the temperature of the heating element 273 may gradually increase and converge to the highest temperature point.

On the other hand, when the amount of frost on the evaporator 30 is large, the flow rate of air flowing into the bypass passage 230 increases, and thus the amount of cooling of the heat generating element 273 by the air flowing through the bypass passage 230 increases. Thus, the highest temperature point of the heating element 273 can be set low by the air flowing through the bypass passage 230.

On the other hand, when the amount of frost on the evaporator 30 is small, the flow rate of the air flowing into the bypass passage 230 decreases, and therefore, the amount of cooling of the heat generating element 273 by the air flowing through the bypass passage 230 decreases. Thus, the highest temperature point of the heating element 273 can be set high by the air flowing through the bypass passage 230.

In the present embodiment, the temperature of the heater element 273 may be detected at the time point when the heater element 273 is turned on. That is, in the present disclosure, it can be understood that after the heating element 273 is turned on, the lowest temperature value of the heating element 273 is detected.

Next, in step S15, after a predetermined period of time has elapsed, the heating element 273 is turned off.

As an example, the heating element 273 may be maintained in an on state for three minutes and then turned off.

When the heating element 273 is closed, the temperature of the heating element 273 may be rapidly decreased due to the air flowing through the bypass passage 230.

As the period during which the heating element 273 is turned off increases, the temperature of the heating element 273 rapidly decreases. In addition, the temperature of the heating element 273 may be rapidly decreased and then gradually decreased from a specific time point.

Next, in step S17, the temperature of the heater element 273 is detected with the heater element 273 closed.

Specifically, the temperature of the heating element 273 may be detected at a specific time point in a state where the heating element 273 is turned off.

In the present embodiment, the temperature of the heater element 273 may be detected at the time point when the heater element 273 is turned off. That is, in the present disclosure, it can be understood that the maximum temperature value of the heating element 273 is detected after the heating element 273 is turned off.

Next, in step S19, the amount of frost on the evaporator 30 may be determined based on the temperature difference between the temperature detected in the state where the heating element 273 is turned on and the temperature detected in the state where the heating element 273 is turned off.

As described above, when the amount of frost on the evaporator 30 is large, the flow rate of air flowing into the bypass passage 230 increases, and therefore, the amount of cooling of the heat generating element 273 by the air flowing through the bypass passage 230 increases. Then, the detected maximum temperature value of the heater element 273 becomes small, and as a result, the temperature difference between the minimum temperature value and the maximum temperature value of the heater element 273 may become large.

In contrast, when the amount of frost on the evaporator 30 is small, the flow rate of air flowing into the bypass passage 230 decreases, and therefore, the amount of cooling of the heat generating element 273 by the air flowing through the bypass passage 230 decreases. Then, the detected maximum temperature value of the heater element 273 becomes large, and as a result, the temperature difference between the minimum temperature value and the maximum temperature value of the heater element 273 may become small.

As described above, by detecting the lowest temperature value and the highest temperature value when the heating element 273 is turned on/off, the cooling amount of the heating element 273 can be accurately determined by the air flowing through the bypass passage 230.

In summary, when the temperature difference between the lowest temperature value and the highest temperature value of the heating element 273 is equal to or less than the reference value, it can be determined that the amount of frost on the evaporator 30 is large. In addition, when it is determined that the amount of frost on the evaporator 30 is large, the defrosting operation can be performed.

Hereinafter, a detailed method for detecting the amount of frost on the above-described evaporator 30 will be described in detail with reference to the accompanying drawings.

Fig. 10 is a flowchart illustrating a method of performing a defrosting operation by determining a time point at which a refrigerator needs to be defrosted according to an embodiment of the present disclosure, and fig. 11 is a view illustrating a temperature change of a heating element according to turning on/off of the heating element before and after frost is formed on an evaporator according to an embodiment of the present disclosure.

Fig. 11 (a) shows a temperature change of the freezing chamber and a temperature change of the heat generating element before frost occurs on the evaporator 30, and fig. 11 (b) shows a temperature change of the freezing chamber and a temperature change of the heat generating element after frost occurs on the evaporator 30. In the present embodiment, it is assumed that the state before occurrence of frost is the state after completion of the defrosting operation.

Referring to fig. 10 and 11, in step S21, the heating element 273 is turned on.

Specifically, the heating element 273 may be turned on in a state where the storage compartment 11 (e.g., a freezing compartment) is subjected to a cooling operation.

As an example, as shown in fig. 11, in the case where the blower 70 is driven, the heating element 273 may be turned on at a specific time point S1.

The blower 70 may be driven for a predetermined period of time to cool the freezing chamber. In this case, the compressors 60 may be driven simultaneously. Therefore, when the blower 70 is driven, the temperature Ft of the freezing chamber may decrease.

On the other hand, when the heating element 273 is turned on, the temperature detected by the sensing element 274 (i.e., the temperature Ht of the heating element 273) may rapidly increase.

Next, in step S22, it may be determined whether the blower 70 is turned on.

As described above, the sensor 270 may detect a temperature change of the heating element 273, which is caused by the air whose flow rate is changed according to the amount of frost on the evaporator 30. Therefore, in the case where no air flow occurs, it is difficult for the sensor 270 to accurately detect the amount of frost on the evaporator 30.

When the blower 70 is driven, in step S23, the temperature Htl of the heat generating element may be detected.

In the present embodiment, the temperature Ht1 of the heater element 273 may be detected at the time point when the heater element 273 is turned on. That is, in the present disclosure, it can be understood that the temperature of the heating element 273 can be detected immediately after the heating element 273 is turned on. Therefore, the detected temperature Ht1 of the heater element may be defined as the lowest temperature in the state where the heater element 273 is turned on.

Here, the temperature of the heating element 273 detected for the first time may be referred to as a "first detected temperature (Ht 1)".

Next, in step S24, it is determined whether the first reference time T1 has elapsed while the heating element 273 is turned on.

While the heating element 273 is maintained in the open state, the temperature detected by the sensing element 274 (i.e., the temperature Ht1 of the heating element 273) may be continuously increased. However, when the heating element 273 is maintained in the open state, the temperature of the heating element 273 may gradually increase and converge to the highest temperature point.

Here, the first reference time T1 for maintaining the heating element 273 in the open state may be 3 minutes, but is not limited thereto.

When the predetermined period of time has elapsed while the heater element 273 is turned on, in step S25, the heater element 273 is turned off.

As shown in fig. 11, the heating element 273 may be turned on at a first reference time T1 and then turned off. When the heating element 273 is closed, the air flowing through the bypass passage 230 may rapidly cool the heating element 273. Therefore, the temperature Ht of the heating element 273 can be rapidly decreased.

However, when the off state of the heating element 273 is maintained, the temperature Ht of the heating element may be gradually decreased, and the rate of decrease thereof is significantly decreased.

Next, in step S26, the temperature Ht2 of the heat generating element may be detected.

That is, the temperature Ht2 of the heater element is detected by the sensing element 274 at a specific time point S2 in a state where the heater element 273 is turned off.

In the present embodiment, the temperature Ht2 of the heater element may be detected at the time point when the heater element 273 is turned off. That is, in the present disclosure, the temperature may be detected immediately after the heating element 273 is turned off. Therefore, the detected temperature Ht2 of the heater element can be defined as the highest temperature in the state where the heater element 273 is turned off.

Here, the temperature of the heating element 273 detected at the second time may be referred to as "second detected temperature (Ht 2)".

In summary, the temperature Ht of the heater element may be first detected at a time point S1 when the heater element 273 is turned on, and may be additionally detected at a time point S2 when the heater element 273 is turned off. In this case, the first detected temperature Ht1 detected for the first time may be the lowest temperature in the state where the heater element 273 is open, and the second detected temperature Ht2 detected additionally may be the highest temperature in the state where the heater element 273 is closed.

Next, in step S27, it is determined whether a temperature steady state has been reached.

Here, the temperature stable state may refer to a state in which the load of the internal refrigerator does not occur, that is, a state in which the cooling of the storage compartment is normally performed. In other words, being in a temperature stable state may mean that the opening/closing operation of the refrigerator door is not performed, or that there is no defect in the sensor 270 or the components for cooling the storage compartment (e.g., the compressor and the evaporator).

That is, the sensor 270 can accurately detect the amount of frost on the evaporator 30 by determining whether or not the temperature stabilization has been reached.

In the present embodiment, in order to determine that the temperature steady state is reached, the amount of temperature change of the freezing chamber in a predetermined period of time may be determined. Alternatively, in order to determine that the temperature steady state is reached, the amount of temperature change of the evaporator 30 may be determined within a predetermined period of time.

For example, a state in which the temperature of the freezing chamber or the temperature of the evaporator 30 does not change by more than 1.5 degrees in a predetermined period of time may be defined as a temperature steady state.

As described above, the temperature Ht of the heat generating element may be rapidly decreased immediately after the heat generating element 273 is turned off, and then, the temperature Ht of the heat generating element may be gradually decreased. Here, whether or not temperature stabilization has been achieved can be determined by determining whether or not the temperature Ht of the heat generating element is normally decreased after being rapidly decreased.

When the temperature steady state is reached, in step S28, a temperature difference Δ Ht between the temperature Ht1 detected when the heater element 273 is turned on and the temperature Ht2 detected when the heater element 273 is turned off may be calculated.

In step S29, it is determined whether the temperature difference Δ Ht is smaller than a first reference temperature value.

Specifically, when the amount of frost on the evaporator 30 is large, the flow rate of air flowing into the bypass passage 230 increases, and thus the amount of cooling of the heat generating element 273 by the air flowing through the bypass passage 230 increases. When the cooling amount is increased, the temperature Ht2 of the heat generating element detected immediately after the heat generating element 273 is turned off may be relatively low as compared to the case where the amount of frost on the evaporator 30 is small.

As a result, when the amount of frost on the evaporator 30 is large, the temperature difference Δ Ht can be small. Therefore, the amount of frost on the evaporator 30 can be determined by the temperature difference Δ Ht. Here, the first reference temperature value may be, for example, 32 degrees.

Next, when the temperature difference Δ Ht is smaller than the first reference temperature value, in step S30, a defrosting operation is performed.

When the defrosting operation is performed, the defrosting device 50 is driven, and the heat generated by the heater is transferred to the evaporator 30, so that the frost generated on the surface of the evaporator 30 is melted.

On the other hand, when the temperature steady state is not reached in step S27, or when the temperature difference Δ Ht is greater than or equal to the first reference temperature value in step S29, the algorithm ends without performing the defrosting operation.

In the present embodiment, the temperature difference Δ Ht may be defined as a "logical temperature" for detecting frosting. The logic temperature may be used as a temperature for determining a time point of a defrosting operation of the refrigerator, and may be used as a temperature for determining a time point at which the heating element 273 is turned on, which will be described later.

Fig. 12 is a flowchart illustrating a control method for determining an operation time point of a heat generating element according to one embodiment of the present disclosure. The present embodiment may be understood as a control method for determining a point of time (step S21) at which the heating element 273 is turned on in fig. 10.

Referring to fig. 11 and 12 together, in step S31, the heating element 273 may be turned off. Here, step S31 may refer to step S25 of fig. 10 described above. That is, the present embodiment can be understood as a control method after step S25.

When the heating element 273 is turned off, in step S32, it is determined whether the logic temperature Δ Ht is less than the second reference temperature value.

It is possible to detect the amount of frost on the evaporator 30 to determine whether the logic temperature Δ Ht is less than the second reference temperature value.

For example, the second reference temperature value may be 35 degrees.

Specifically, in fig. 10, it has been described that the first reference temperature value for performing the defrosting operation is 32 degrees. In this case, the second reference temperature value may be set to be greater than the first reference temperature value. That is, even when the defrosting operation is completed, the amount of frost on the evaporator 30 may be large, and thus the amount of frost on the evaporator 30 may be detected again.

When the logic temperature Δ Ht is less than the second reference temperature value, it is determined whether the accumulated operating time of the freezing compartment has reached the second reference time in step S33. Here, the second reference time may be, for example, 1 hour.

Next, when the logic temperature Δ Ht is less than the second reference temperature value, it may be determined whether the blower 70 is being driven in step S34.

When the blower 70 is driven, it is determined whether the temperature stable state is reached in step S35, and when the temperature stable state is reached, the heat generating element 273 is turned on in step S36.

Here, the temperature stable state may refer to a state in which the load of the internal refrigerator does not occur or a state in which the cooling of the storage compartment is normally performed. In other words, being in a temperature stable state may mean that the opening/closing operation of the refrigerator door is not performed, or that there is no defect in the sensor 270 or the components for cooling the storage compartment (e.g., the compressor and the evaporator).

In the present embodiment, in order to determine the temperature stable state, the heating element 273 may be turned on/off at predetermined time intervals. For example, in determining the temperature stable state, the heating element 273 may be turned on/off at predetermined time intervals. In this case, a time point at which the heating element 273 is turned on/off to determine the temperature steady state may be a time point at which the blower 70 is turned on (S0).

That is, the heating element 273 may be turned on/off at predetermined time intervals immediately after the blower 70 is turned on. For example, the heating element 273 may be repeatedly turned on/off every 10 seconds when the blower 70 is driven.

Further, it is determined whether the detected temperature variation of the freezing chamber temperature (Ft) and the temperature variation of the heating element temperature (Ht) are less than a third reference temperature value by detecting the temperature variation of the freezing chamber temperature (Ft) or the heating element temperature (Ht) for a predetermined period of time. For example, the third reference temperature value may be 0.5 degrees, but is not limited thereto.

As shown in fig. 11, since the blower fan 70 is driven, the temperature Ft of the freezing chamber may be gradually decreased. In addition, by turning on/off the heating element 273, the temperature Ht of the heating element can be increased by a certain amount.

In the present embodiment, a case where the detected variation amount of the temperature (Ft) of the freezing compartment and the detected variation amount of the temperature (Ht) of the heating element are less than the third reference temperature value may be determined as the temperature stable state.

On the other hand, when the logic temperature is equal to or higher than the second reference temperature value in step S32, or when the accumulated operating time does not reach the second reference time in step S33, the process returns to step S31.

Further, when the blower is not driven in step S34, or when the temperature stable state is not reached in step S35, the process returns to step S31.

Meanwhile, in the present embodiment, it is described that the amount of frost on the evaporator 30 is detected based on the temperature difference between the first detected temperature Ht1 detected in the state where the heating element 273 is turned on and the second detected temperature Ht2 detected in the state where the heating element 273 is turned off.

However, alternatively, the temperature of the heating element may be detected in a state where the heating element 273 is turned on. The amount of frost on the evaporator 30 can be detected based on the temperature difference between the first detected temperature (Ht1) which is the lowest value of the detected temperatures of the heat generating elements and the second detected temperature (Ht2) which is the highest temperature of the detected temperatures of the heat generating elements.

That is, the amount of frost on the evaporator 30 can be detected by the detection temperatures Ht1 and Ht2 in the state where the heater element 273 is open, without detecting the temperature of the heater element in the state where the heater element 273 is closed.

According to the method of controlling the refrigerator, a point of time at which defrosting is required can be accurately determined using a sensor in the bypass passage having an output value that varies according to the amount of frost on the evaporator. Therefore, when the amount of frost is large, a quick defrosting operation can be performed, and when the amount of frost is small, a phenomenon that defrosting is started can be prevented.

Claims

1. A method of controlling a refrigerator, the method comprising:

allowing a heating element of the sensor responsive to the change in air flow to turn on for a predetermined period of time and then off;

detecting a first detection temperature (Ht1) of the heat generating element in a state where the heat generating element is turned on, and detecting a second detection temperature (Ht2) of the heat generating element in a state where the heat generating element is turned off; and

detecting an amount of frost on an evaporator based on a temperature difference between the first detected temperature (Ht1) and the second detected temperature (Ht2),

wherein the sensor is disposed in a bypass passage configured to allow air to flow to bypass the evaporator,

wherein the first detected temperature (Ht1) is a temperature detected by a sensing element of the sensor immediately after the heating element is turned on, and the second detected temperature (Ht2) is a temperature detected by the sensing element of the sensor immediately after the heating element is turned off.

2. A method of controlling a refrigerator, the method comprising:

wherein the first detected temperature (Ht1) is a lowest temperature value during a period in which the heat generating element is turned on, and the second detected temperature (Ht2) is a highest temperature value after the heat generating element is turned off.

3. The method of claim 1 or 2, wherein the refrigerator comprises a cold air duct configured to define a heat exchange space, and the bypass channel is arranged recessed in the cold air duct.

4. The method of claim 3, wherein the refrigerator further comprises a channel cover configured to cover the bypass channel to separate the bypass channel from the heat exchange space.

5. The method of claim 1 or 2, further comprising: determining whether a temperature difference between the first detected temperature (Ht1) and the second detected temperature (Ht2) is less than a first reference difference; and

performing a defrosting operation of removing frost generated on a surface of the evaporator when it is determined that the temperature difference between the first detected temperature (Ht1) and the second detected temperature (Ht2) is less than the first reference difference.

6. The method according to claim 1 or 2, wherein the heating element is turned on while cooling the storage compartment of the refrigerator.

7. The method according to claim 1 or 2, wherein the heating element is turned on while driving a blower for cooling the storage compartment.

8. The method of claim 1 or 2, further comprising:

determining whether a temperature difference between the first detected temperature (Ht1) and the second detected temperature (Ht2) is less than a second reference difference when the heat generating element is turned on for the predetermined period of time and then turned off,

wherein the heating element is turned on when a temperature difference between the first detected temperature (Ht1) and the second detected temperature (Ht2) is less than the second reference difference.

9. The method of claim 8, wherein the heating element is turned on based on a cumulative cooling operation time of the storage compartment when the temperature difference between the first detected temperature (Ht1) and the second detected temperature (Ht2) is less than the second reference difference.

10. The method of claim 1 or 2, further comprising:

when the heating element is turned on for the predetermined period of time and then turned off, the heating element is allowed to be turned on based on the accumulated cooling operation time of the storage compartment.

11. A method of controlling a refrigerator, the method comprising:

allowing a heating element of the sensor responsive to the change in the air flow rate to operate for a predetermined period of time;

detecting a temperature of the heating element while the heating element is turned on;

detecting an amount of frost on an evaporator based on a temperature difference between a first detected temperature (Ht1) as a lowest value and a second detected temperature (Ht2) as a highest value among detected temperatures of the heat generating elements; and

performing a defrosting operation of removing frost generated on a surface of the evaporator when it is determined that a temperature difference between the first detected temperature (Ht1) and the second detected temperature (Ht2) is less than a first reference difference,

wherein the sensor is disposed in a bypass passage configured to allow air to flow to bypass the evaporator.

12. The method of claim 11, wherein the first and second light sources are selected from the group consisting of,

wherein, the refrigerator includes: a cool air duct configured to define a heat exchange space, and the bypass passage is arranged to be recessed in the cool air duct; and a passage cover configured to cover the bypass passage so as to separate the bypass passage from the heat exchange space.

13. The method of claim 11, wherein the heating element is turned on while cooling the storage compartment of the refrigerator.

14. The method according to claim 11, wherein the heating element is turned on while a blower for cooling the storage compartment is driven.

15. A refrigerator, comprising:

an inner shell configured to define a storage space;

a cold air duct configured to guide air to flow in the storage space and to define a heat exchange space together with the inner case;

an evaporator disposed in the heat exchange space;

a bypass passage configured to allow air to flow to bypass the evaporator;

a sensor including a heat generating element disposed in the bypass passage and a sensing element configured to detect a temperature of the heat generating element; and

a controller configured to detect an amount of frost on an evaporator based on a temperature difference between a first detected temperature (Ht1) of the heat generating element detected in a state in which the heat generating element is opened and a second detected temperature (Ht2) of the heat generating element detected in a state in which the heat generating element is closed,

wherein the first detected temperature (Ht1) is a lowest temperature value during a period in which the heat generating element is turned on, and

wherein the second detected temperature (Ht2) is a highest temperature value after the heating element is turned off.

16. The refrigerator of claim 15, wherein the first detected temperature (Ht1) is a temperature detected by the sensing element immediately after the heating element is turned on.

17. The refrigerator of claim 15, wherein the second detected temperature (Ht2) is a temperature detected by the sensing element immediately after the heating element is turned off.

18. The refrigerator of claim 15, wherein the bypass channel is arranged to be recessed in the cool air duct.

19. The refrigerator of claim 18, further comprising a channel cover configured to cover the bypass channel to separate the bypass channel from the heat exchange space.