AU2019243005B2 - Refrigerator and method for controlling same - Google Patents

Abstract

A method for controlling a refrigerator according to an embodiment of the present invention comprises the steps of: operating, for a set duration, a heating element of a sensor disposed on a bypass channel which allows air to bypass an evaporator disposed in a heat-exchange space; sensing the temperature of the heating element in on or off state; and sensing the blockage of an air channel in the heat-exchange space on the basis of the difference in value of the temperature between a first sensed temperature (Ht1), which is the lowest value, and a second sensed temperature (Ht2), which is the highest value, from among the sensed temperatures of the heating element.

Description

REFRIGERATOR AND METHOD FOR CONTROLLING SAME

[Technical Field]

[1] The present disclosure relates to a refrigerator and a method for

controlling the same.

[Background]

[2] Refrigerators are household appliances that are capable of storing

objects such as foods at a low temperature in a storage chamber provided in

a cabinet. Since the storage space is surrounded by heat insulation wall, the

inside of the storage space may be maintained at a temperature less than an

external temperature.

[3] The storage space may be classified into a refrigerating storage space

or a freezing storage space according to a temperature range of the storage

space.

[4] The refrigerator may further include an evaporator for supplying cool air

to the storage space. Air in the storage space is cooled while flowing to a

space, in which the evaporator is disposed, so as to be heat-exchanged with

the evaporator, and the cooled air is supplied again to the storage space.

[5] Here, if the air heat-exchanged with the evaporator is contained in

moisture, when the air is heat-exchanged with the evaporator, the moisture is

frozen on a surface of the evaporator to generate frost on the surface of the

evaporator.

89731636.3

[6] Since flow resistance of the air acts on the frost, the more an amount of

frost frozen on the surface of the evaporator increases, the more the flow

resistance increases. As a result, heat-exchange efficiency of the evaporator

may be deteriorated, and thus, power consumption may increase.

[7] Thus, the refrigerator further includes a defroster for removing the frost

on the evaporator.

[8] A defrosting cycle variable method is disclosed in Korean Patent

Publication No. 2000-0004806 that is a prior art document.

[9] In the prior art document, the defrosting cycle is adjusted using a

cumulative operation time of the compressor and an external temperature.

[10] However, like the prior art document, when defrosting cycle is

determined only using the cumulative operation time of the compressor and

the external temperature, an amount of frost (hereinafter, referred to as a frost

generation amount) on the evaporator is not reflected. Thus, it is difficult

accurately determine the time point at which the defrosting is required.

[11] That is, the frost generation amount may increase or decrease

according to various environments such as the user's refrigerator usage

pattern and the degree to which air retains moisture. In the case of the prior

art document, there may be a disadvantage in that the defrosting cycle is

determined without reflecting the various environments.

[12] In the prior art document, it is only possible to detect the amount of frost

on the evaporator, but it is impossible to detect a phenomenon in which the

cool air passage through which the cool air circulating inside the refrigerator

flows is clogged by the frost. That is, when frost grows in the cool air inlet, the

89731636.3 cool air outlet, or the blowing fan constituting the cool air passage, resistance to the flow of cool air occurs, and in some cases, the cool air passage is completely clogged, preventing the cool air cannot from circulating. When circulation of the cool air is not properly performed, there is a problem that the cooling performance is greatly deteriorated, and power consumption is increased.

[13] It is desired to address or ameliorate one or more disadvantages or

limitations associated with the prior art, provide a refrigerator and/or a method

for controlling a refrigerator, or to at least provide the public with a useful

alternative.

[Summary]

[14] According to a first aspect, the present disclosure broadly comprises a

method for controlling a refrigerator, the method comprising: operating a heat

generating element of a sensor unit disposed in a bypass passage for a

predetermined period of time, the bypass passage allowing air flow to bypass

an evaporator disposed in a heat-exchange space; sensing a plurality of

temperatures of the heat generating element in a turned on state or turned off

state; and sensing clogging of an air passage in the heat-exchange space or

a failure of the sensor or an amount of frost on the evaporator based on a

temperature difference between a first temperature (Htl) that is a lowest value

and a second temperature (Ht2) that is a highest value among the sensed

plurality of temperatures of the heat generating element; and performing a

defrosting operation of the evaporator when a temperature difference value

89731636.3 between the first detection temperature (Htl) and the second detection temperature (Ht2) is less than a first reference value.

[15] The first temperature (Htl) may be a temperature sensed by a sensing

element of the sensor unit immediately after the heat generating element is

turned on.

[16] The second temperature (Ht2) may be a temperature sensed by a

sensing element of the sensor unit immediately after the heat generating

element is turned off.

[17] The first temperature (Htl) may be a lowest temperature value during a

period of time when the heat generating element is turned on.

[18] The second temperature (Ht2) may be a highest temperature value

during a period of time when the heat generating element is turned on.

[19] The refrigerator may comprise a cool air duct configured to define a

heat-exchange space, and a passage cover configured to cover the bypass

passage so as to partition the bypass passage from the heat exchange space,

wherein the bypass passage is disposed to be recessed in the cool air duct.

[20] The method may further comprise: sensing an updated temperature

difference between the first temperature (Htl) and the second temperature

(Ht2) after the defrosting operation is completed, and displaying a notification

indicating a failure of the sensor unit when the updated temperature difference

exceeds a second reference value.

[21] When the updated temperature difference is less than the second

reference value, the method may further comprise: determining whether the

updated temperature difference is less than a third reference value, the third

89731636.3 reference value being a value less than the second reference value, and displaying a notification indicating the clogging of the air passage in the heat exchange space when the updated temperature difference exceeds the third reference value.

[22] The notification indicating the clogging of the air passage may further

comprise one or more notifications indicating: clogging of a cool air inflow hole

of a cool air duct defining the heat-exchange space, clogging of a cool air

discharge hole of the cool air duct, or clogging of a blowing fan provided in the

cool air duct or clogging of the bypass passage.

[23] When the updated temperature difference value is less than the third

reference value, the method further may comprise: determining whether the

updated temperature difference is less than a fourth reference value, the fourth

value being a value less than the third reference value and greater than the

first reference value, and repeating the defrosting operation on the evaporator

when the updated temperature difference is less than the fourth reference

value.

[24] When the updated temperature difference is less than the fourth

reference value, the method may further comprise: determining whether the

updated temperature difference has increased by a predetermined value or

more when compared to the temperature difference before the temperature

difference was updated, and repeating the defrosting operation on the

evaporator when the updated temperature difference value has increased by

a predetermined value or more compared to the temperature difference value

before the temperature difference has been updated.

89731636.3

[25] The method may further comprise: repeating the defrosting operation

on the evaporator according to whether the updated temperature difference is

less than the first reference value when the updated temperature difference

value is not increased by a predetermined value or more compared to the

temperature difference value before the temperature difference value has

been updated.

[26] According to a further aspect, the present disclosure may broadly

provide a refrigerator comprising: an inner case defining a storage space; a

cooling duct configured to guide flow of air to the storage space; a heat

exchange space defined between the inner case and the cooling duct; an

evaporator disposed in the heat exchange space; a bypass passage

configured to allow air flow to bypass the evaporator; a sensor unit including

a heat generating element disposed in the bypass passage and a sensing

element configured to sense a temperature of the heat generating element;

and a controller configured to sense clogging of an air passage in the heat

exchange space or a failure of the sensor or an amount of frost on the

evaporator based on a temperature difference between a first temperature

(Htl) that is a lowest value and a second temperature (Ht2) that is a highest

value among the detected plurality of temperatures of the heat generating

element, wherein the controller is configured to perform a defrosting operation

of the evaporator, when the temperature difference value between the first

detection temperature (Htl) and the second detection temperature (Ht2) is less

than a first reference value.

89731636.3

[27] The first temperature (Ht) may be a temperature sensed by the

sensing element immediately after the heat generating element is turned on,

and wherein the second temperature (Ht2) is a temperature sensed by the

sensing element immediately after the heat generating element is turned off.

[28] The first temperature (Htl) may be a lowest temperature value during a

period of time when the heat generating element is turned on, wherein the

second temperature (Ht2) is a highest temperature value during a period of

time when the heat generating element is turned on.

[29] The refrigerator may further comprise a passage cover configured to

cover the bypass passage so as to partition the bypass passage from the heat

exchange space, wherein the bypass passage is disposed to be recessed in

the cool air duct.

[30] The controller may be configured to sense an updated temperature

difference between the first temperature (Htl) and the second temperature

(Ht2) after the defrosting operation is completed, wherein a notification

indicating a failure of the sensor unit is displayed when the updated

temperature difference value exceeds a second reference value.

[31] When the updated temperature difference value is less than the second

reference value, the controller may be configured to: determine whether the

updated temperature difference is less than a third reference value, the third

value being a value less than the second reference value, and display a

notification indicating the clogging of the air passage in the heat-exchange

space when the updated temperature difference value exceeds the third

reference value.

89731636.3

[32] The notification indicating the clogging of the air passage may further

comprise one or more notifications indicating: clogging of a cool air inflow hole

of a cool air duct defining the heat-exchange space, clogging of a cool air

discharge hole of the cool air duct, or clogging of a blowing fan provided in the

cool air duct or clogging of the bypass passage.

[33] When the updated temperature difference value is less than the third

reference value, the controller is configured to: determine whether the updated

temperature difference is less than a fourth reference value, the fourth

reference value being a value less than the third reference value, and repeat

the defrosting operation of the evaporator when the updated temperature

difference value is less than the fourth reference value.

[34] The present disclosure may provide a refrigerator and a control method

thereof, which determines a time point for a defrosting operation using

parameters that vary depending on the amount of frost on an evaporator.

[35] The present disclosure may also provide a refrigerator and a control

method thereof, which accurately determine a time point at which defrosting is

necessary according to the amount of frost on an evaporator using a sensor

having an output value that varies depending on the flow rate of air.

[36] The present disclosure may also provide a refrigerator and a control

method thereof, which accurately determine an exact defrost time point even

when the precision of a sensor used to determine the defrost time point is low.

[37] The present disclosure may also provide a refrigerator capable of

detecting clogging of an air passage of the refrigerator using a sensor of which

89731636.3 an output value varies according to a flow rate of air and a control method thereof.

[38] The present disclosure may also provide a refrigerator capable of

accurately determining the cause of clogging of an air passage based on an

output value of a sensor, and a control method thereof.

[39] A method for controlling a refrigerator may include detecting clogging of

an air passage in the heat-exchange space based on a temperature difference

between a first detection temperature (Htl) that is a lowest value and a second

detection temperature (Ht2) that is a highest value among detection

temperatures of a heat generating element.

[40] The first detection temperature (Htl) may be a temperature detected by

a sensing element of the sensor immediately after the heat generating element

is turned on, and the second detection temperature (Ht2) may be a

temperature detected by a sensing element of the sensor immediately after

the heat generating element is turned off.

[41] The first detection temperature (Htl) may be a lowest temperature

value during a period of time when the heat generating element is turned on,

and the second detection temperature (Ht2) may be a highest temperature

value during a period of time when the heat generating element is turned on.

[42] The method may further include performing a defrosting operation of

the evaporator when a temperature difference value between the first detection

temperature (Htl) and the second detection temperature (Ht2) is less than a

first reference value.

89731636.3

[43] The method may further include updating a temperature difference

value between the first detection temperature (Htl) and the second detection

temperature (Ht2) after the defrosting operation is completed, and failure of

the sensor may be displayed when the updated temperature difference value

exceeds a second reference value greater than the second reference value.

[44] The method may further include determining whether the updated

temperature difference value is less than a third reference value less than the

second reference value when the updated temperature difference value is less

than the second reference value, and displaying the clogging of the air

passage in the heat-exchange space when the updated temperature

difference value exceeds the third reference value.

[45] The display of the clogging of the air passage is at least one display of

clogging of a cool air inflow hole of a cool air duct defining the heat-exchange

space, clogging of a cool air discharge hole of the cool air duct, clogging of a

blowing fan provided in the cool air duct or clogging of the bypass passage.

[46] Therefore, even after the defrosting operation is completed, it is

possible to identify whether the air passage of the refrigerator is clogged by

using the output value of the sensor and immediately notify a user of clogging

of the air passage, thus making it possible to take measures immediately when

the clogging of the air passage occurs. Therefore, it is possible to determine

not only the cause of the clogging of the air passage, but also whether the

sensor is malfunctioning, thus achieving accurate diagnosis and making

maintenance and management easy.

89731636.3

[47] The method may further include determining whether the updated

temperature difference value is less than a fourth reference value less than the

third reference value when the updated temperature difference value is less

than the third reference value, and again performing the defrosting operation

of the evaporator when the updated temperature difference value is less than

the fourth reference value.

[48] The method may further include determining whether the updated

temperature difference value is increased by a predetermined value or more

compared to the temperature difference value before the temperature

difference value has been updated when the updated temperature difference

value is less than the fourth reference value, and again performing the

defrosting operation of the evaporator when the updated temperature

difference value is increased by a predetermined value or more compared to

the temperature difference value before the temperature difference value has

been updated.

[49] The method may further include again performing the defrosting

operation of the evaporator according to whether the updated temperature

difference value is less than the first reference value when the updated

temperature difference value is not increased by a predetermined value or

more compared to the temperature difference value before the temperature

difference value has been updated.

[50] A refrigerator may include a bypass passage configured to allow air flow

to bypass the evaporator, a heat generating element disposed in the bypass

passage, a sensor including a sensing element for detecting a temperature of

89731636.3 the heat generating element and a controller configured to detect clogging of an air passage in the heat-exchange space based on a temperature difference between a first detection temperature (Htl) that is a lowest value and a second detection temperature (Ht2) that is a highest value among detection temperatures of the heat generating element.

[51] According to the present disclosure, since the time point at which the

defrosting is required is determined using the sensor having the output value

varying according to the amount of frost generated on the evaporator in the

bypass passage, the time point at which the defrosting is required may be

accurately determined.

[52] In addition, even when the precision of a sensor used to determine a

defrost time point is low, it is possible to accurately determine the defrost time

point, thus significantly reducing the cost of the sensor.

[53] Even after the defrosting operation is completed, it is possible to identify

whether the air passage of the refrigerator is clogged by using the output value

of the sensor and immediately notify a user of clogging of the air passage, thus

making it possible to take measures immediately when the clogging of the air

passage occurs.

[54] Therefore, it is possible to determine not only the cause of the clogging

of the air passage, but also whether the sensor is malfunctioning, thus

achieving accurate diagnosis and making maintenance and management easy.

[55] It is possible to prevent a phenomenon that the air passage is

completely clogged by frost, thus improving cooling performance by active air

circulation by fundamentally preventing the growth of frost in the air passage.

89731636.3

[56] The term "comprising" as used in the specification and claims means

"consisting at least in part of." When interpreting each statement in this

specification that includes the term "comprising," features other than that or

those prefaced by the term may also be present. Related terms "comprise" and

"comprises" are to be interpreted in the same manner.

[57] The reference in this specification to any prior publication (or

information derived from it), or to any matter which is known, is not, and should

not be taken as, an acknowledgement or admission or any form of suggestion

that that prior publication (or information derived from it) or known matter forms

part of the common general knowledge in the field of endeavour to which this

specification relates.

[Brief Description of the Drawings]

[58] FIG. 1 is a schematic longitudinal cross-sectional view of a refrigerator

according to an embodiment of the present disclosure.

[59] FIG. 2 is a perspective view of a cool air duct according to an

embodiment of the present disclosure.

[60] FIG. 3 is an exploded perspective view illustrating a state in which a

passage cover and a sensor are separated from each other in the cool air duct.

[61] FIG. 4 is a view illustrating a flow of air in a heat exchange space and a

bypass passage before and after frost is generated.

[62] FIG. 5 is a schematic view illustrating a state in which a sensor is

disposed in the bypass passage.

89731636.3

[63] FIG. 6 is a view of the sensor according to an embodiment of the

present disclosure.

[64] FIG. 7 is a view illustrating a thermal flow around the sensor depending

on a flow of air flowing through the bypass passage.

[65] FIG. 8 is a control block diagram of a refrigerator according to an

embodiment of the present disclosure.

[66] FIG. 9 is a flowchart showing a method of performing a defrost operation

by determining a time point when a refrigerator needs to be defrosted

according to an embodiment of the present disclosure.

[67] FIG. 10 is a view showing changes in a temperature of a heat

generating element according to the on/off of the heat generating element

before and after frost on the evaporator according to an embodiment of the

present disclosure.

[68] FIG. 11 is a flowchart schematically showing a method of detecting

clogging of an air passage of a refrigerator according to an embodiment of the

present disclosure.

[69] FIG. 12 is a flowchart showing a detailed method for detecting clogging

of an air passage of a refrigerator according to an embodiment of the present

disclosure.

[Detailed Description]

[70] 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 below in more detail

89731636.3 with reference to the accompanying drawings. It is noted that the same or similar components in the drawings are designated by the same reference numerals as far as possible even if they are shown in different drawings.

Further, in description of embodiments of the present disclosure, when it is

determined that detailed descriptions of well-known configurations or functions

disturb understanding of the embodiments of the present disclosure, the

detailed descriptions will be omitted.

[71] Also, in the description of the embodiments of the present disclosure,

the terms such as first, second, A, B, (a) and (b) may be used. Each of the

terms is merely used to distinguish the corresponding component from other

components, and does not delimit an essence, an order or a sequence of the

corresponding component. It should be understood that when one component

is "connected", "coupled" or "joined" to another component, the former may be

directly connected or jointed to the latter or may be "connected", coupled" or

"joined" to the latter with a third component interposed therebetween.

[72] FIG. 1 is a schematic longitudinal cross-sectional view of a refrigerator

according to an embodiment of the present disclosure, FIG. 2 is a perspective

view of a cool air duct according to an embodiment of the present disclosure,

and FIG. 3 is an exploded perspective view illustrating a state in which a

passage cover and a sensor are separated from each other in the cool air duct.

[73] Referring to FIGS. 1 to 3, a refrigerator 1 according to an embodiment

of the present disclosure may include an inner case 12 defining a storage

space 11.

89731636.3

[74] The storage space may include one or more of a refrigerating storage

space and a freezing storage space.

[75] A cool air duct 20 providing a passage, through which cool air supplied

to the storage space 11 flows, in a rear space of the storage space 11. Also,

an evaporator 30 is disposed between the cool air duct 20 and a 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.

[76] Thus, air of the storage space 11 may flow to the heat exchange space

222 between the cool air duct 20 and the rear wall 13 of the inner case 12 and

then be heat-exchanged with the evaporator 30. Thereafter, the air may flow

through the inside of the cool air duct 20 and then be supplied to the storage

space 11.

[77] The cool air duct 20 may include, but is not limited thereto, a first duct

210 and a second duct 220 coupled to a rear surface of the first duct 210.

[78] A front surface of the first duct 210 is a surface facing the storage space

11, and a rear surface of the first duct 220 is a surface facing the rear wall 13

of the inner case 12.

[79] A cool air passage 212 may be provided between the first duct 210 and

the second duct 220 in a state in which the first duct 210 and the second duct

220 are coupled to each other.

[80] Also, a cool air inflow hole 221 may be defined in the second duct 220,

and a cool air discharge hole 211 may be defined in the first duct 210.

89731636.3

[81] A blower fan (not shown) may be provided in the cool air passage 212.

Thus, when the blower fan rotates, air passing through the evaporator 13 is

introduced into the cool air passage 212 through the cool air inflow hole 221

and is discharged to the storage space 11 through the cool air discharge hole

211.

[82] 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.

[83] Thus, the air in the storage space 11 ascends to be heat-exchanged

with the evaporator 30 and then is introduced into the cool air inflow hole 221.

[84] According to this arrangement, when an amount of frost generated on

the evaporator 30 increases, an amount of air passing through the evaporator

30 may be reduced to deteriorate heat exchange efficiency.

[85] In this embodiment, a time point at which defrosting for the evaporator

30 is required may be determined using a parameter that is changed according

to the amount of frost generated on the evaporator 30.

[86] For example, the cool air duct 20 may further include a frost generation

sensing portion configured so that at least a portion of the air flowing through

the heat exchange space 222 is bypassed and configured to determine a time

point, at which the defrosting is required, by using the sensor having a different

output according to a flow rate of the air.

[87] The frost generation sensing portion 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.

89731636.3

[88] Although not limited, the bypass passage 230 may be provided in a

recessed shape in the first duct 210. Alternatively, the bypass passage 230

may be provided in the second duct 220.

[89] 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.

[90] The bypass passage 230 may extend from the cool air duct 20 in a

vertical direction.

[91] The bypass passage 230 may be disposed to face the evaporator 30

within a left and right width range of the evaporator 30 so that the air in the

heat exchange space 222 is bypassed to the bypass passage 230.

[92] The frost generation sensing portion may further include a passage

cover 260 that allows the bypass passage 230 to be partitioned from the heat

exchange space 222.

[93] The passage cover 260 may be coupled to the cool air duct 20 to cover

at least a portion of the bypass passage 230 extending vertically.

[94] The passage cover 260 may include a cover plate 261, an upper

extension portion 262 extending upward from the cover plate 261, and a barrier

263 provided below the cover plate 261.

[95] FIG. 4 is a view illustrating a flow of air in the heat exchange space and

the bypass passage before and after frost is generated.

[96] (a) of FIG. 4 illustrates a flow of air before frost is generated, and (b) of

FIG. 4 illustrates a flow of air after frost is generated. In this embodiment, as

89731636.3 an example, it is assumed that a state after a defrosting operation is complicated is a state before frost is generated.

[97] First, referring to (a) of FIG. 4, in the case in which frost does not exist

on the evaporator 30, or an amount of generated frost is remarkably small,

most of the air passes through the evaporator 30 in the heat exchange space

222 (see arrow A). On the other hand, some of the air may flow through the

bypass passage 230 (see arrow B).

[98] Referring to (b) of FIG. 4, when the amount of frost generated on the

evaporator 30 is large (when the defrosting is required), since the frost of the

evaporator 30 acts as flow resistance, an amount of air flowing through the

heat exchange space 222 may decrease (see arrow C), and an amount of air

flowing through the bypass passage 230 may increase (see arrow D).

[99] As described above, the amount (or flow rate) of air flowing through the

bypass passage 230 varies according to an amount of frost generated on the

evaporator 30.

[100] In this embodiment, the sensor 270 may have an output value that

varies according to a change in flow rate of the air flowing through the bypass

passage 230. Thus, whether the defrosting is required may be determined

based on the change in output value.

[101] Hereinafter, a structure and principle of the sensor 270 will be described.

[102] FIG. 5 is a schematic view illustrating a state in which the sensor is

disposed in the bypass passage, FIG. 6 is a view of the sensor according to

an embodiment of the present disclosure, and FIG. 7 is a view illustrating a

89731636.3 thermal flow around the sensor depending on a flow of air flowing through the bypass passage.

[103] Referring to FIGS. 5 to 7, the sensor 270 maybe disposed atone point

in the bypass passage 230. Thus, 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 a flow rate of air.

[104] The sensor 270 maybe disposed at a position spaced from each of an

inlet 231 and an outlet 232 of the bypass passage 230. For example, the

sensor 270 may be positioned a central portion of the bypass passage 230.

[105] Since the sensor 270 is disposed on the bypass passage 230, the

sensor 270 may face the evaporator 30 within the left and right width range of

the evaporator 30.

[106] The sensor 270 may be, for example, a generated heat temperature

sensor. Particularly, the sensor 270 may include a sensor PCB 271, a heat

generating element 273 installed on the sensor PCB 271, and a sensing

element 274 installed on the sensor PCB 271 to sense a temperature of the

heat generating element 273.

[107] The heat generating element 273 maybe a resistor that generates heat

when current is applied.

[108] The sensing element 274 may sense a temperature of the heat

generating element 273.

[109] When a flow rate of air flowing through the bypass passage 230 is low,

since a cooled amount of the heat generating element 273 by the air is small,

a temperature sensed by the sensing element 274 is high.

89731636.3

[110] On the other hand, if a flow rate of the air flowing through the bypass

passage 230 is large, since the cooled amount of the heat generating element

273 by the air flowing through the bypass passage 230 increases, a

temperature sensed by the sensing element 274 decreases.

[111] The sensor PCB 271 may determine a difference between a

temperature sensed by the sensing element 274 in a state in which the heat

generating element 273 is turned off and a temperature by the sensing element

274 in a state in which the heat generating element 273 is turned on.

[112] The sensor PCB 271 may determine whether the difference value

between the states in which the heat generating element 273 is turned on/off

is less than a reference difference value.

[113] For example, referring to FIGS. 4 and 7, when an amount of frost

generated on the evaporator 30 is small, a flow rate of air flowing to the bypass

passage 230 is small. In this case, a heat flow of the heat generating element

273 is little, and a cooled amount of the heat generating element 273 by the

air is small.

[114] On the other hand, when the amount of frost generated on the

evaporator 30 is large, a flow rate of air flowing to the bypass passage 230 is

large. Then, the heat flow and cooled amount of the heat generating element

273 are large by the air flowing along the bypass passage 230.

[115] Thus, the temperature sensed by the sensing element 274 when the

amount of frost generated on the evaporator 30 is large is less than that sensed

by the sensing element 274 when the amount of frost generated on the

evaporator 30 is small.

89731636.3

[116] Thus, in this embodiment, when the difference between the temperature

sensed by the sensing element 274 in the state in which the heat generating

element 273 is turned on and the temperature by the sensing element 274 in

the state in which the heat generating element 273 is turned off is less than

the reference temperature difference, it may be determined that the defrosting

is required.

[117] According to this embodiment, the sensor 270 may sense a variation in

temperature of the heat generating element 273, which varies by the air of

which a flow rate varies according to the amount of generated frost to

accurately determine a time point, at which the defrosting is required,

according to the amount of frost generated on the evaporator 30.

[118] The sensor 270 maybe further 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 in which the sensor housing 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 a cover portion.

[119] The sensor housing 271 may surround the sensor PCB 271, the heat

generating element 273, and the temperature sensor 274.

[120] FIG. 8 is a control block diagram of a refrigerator according to an

embodiment of the present disclosure.

[121] Referring to FIG. 8, the refrigerator 1 according to an embodiment of

the present disclosure may include the sensor 270 described above, a

defrosting device 50 operating for defrosting the evaporator 30, a compressor

89731636.3

60 for compressing refrigerant, a blowing fan 70 for generating air flow, and a

controller 40 for controlling the sensor 270, the defrosting device 50, the

compressor 60 and the blowing fan 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

spaced apart from a position adjacent to the evaporator 30.

[123] The defrosting device 50 may further include a defrost temperature

sensor. The defrost temperature sensor may detect an ambient temperature

of the defrosting device 50. A temperature value detected by the defrost

temperature sensor may be used as a factor that determines when the heater

is turned on or off.

[124] The compressor 60 is a device for compressing low-temperature low

pressure refrigerant into a high-temperature high-pressure supersaturated

gaseous refrigerant. 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 to an

expander (not shown) and is expanded to a low-temperature low-pressure two

phase refrigerant.

[125] Further, the low-temperature low-pressure two-phase refrigerant is

evaporated as the low-temperature low-pressure gaseous refrigerant while

89731636.3 passing through the evaporator 30. In this process, the refrigerant flowing through the evaporator 30 may exchange heat with outside air, that is, air flowing through the heat exchange space 222, thereby archiving air cooling.

[126] The blowing fan 70 is provided in the cool air passage 212 to generate

air flow. Specifically, when the blowing fan 70 is rotated, air passing through

the evaporator 30 flows into the cool air passage 212 through the cool air inflow

hole 221 and is then discharged to the storage compartment 11 through the

cool air discharge hole 211.

[127] The controller 40 may control the heat generating element 273 of the

sensor 270 to be turned on at regular cycles.

[128] In order to determine when defrosting is necessary, the heat generating

element 273 may maintain a turned-on state for a predetermined period of time,

and the temperature of the heat generating element 273 may be detected by

the sensing element 274.

[129] After the heat generating element 273 is turned on for the

predetermined period of time, the heat generating element 274 is turned off,

and the sensing element 274 may detect the temperature of the heat

generating element 273 which is turned off. In addition, the sensor PCB 263

may determine whether the maximum value of the temperature difference

between the turned-on/off state of the heat generating element 273 is equal to

or less than a reference difference value.

[130] In addition, it is determined that defrosting is necessary when the

maximum value of the temperature difference between the turned-on/off states

of the heat generating element 273 is equal to or less than the reference

89731636.3 difference value, and the defrosting device 50 may be turned on by the controller 40.

[131] Although it has been described above that the sensor PCB 263

determines whether the temperature difference between the turned-on/off

states of the heat generating element 273 is equal to or less than the reference

difference value, alternatively, the controller 40 may determine whether the

temperature difference between the turned-on/off states of the heat generating

element 273 is equal to or less than the reference difference value, and control

the defrosting device 50 according to a result of the determination. That is, the

sensor PCB 263 and the controller 40 may be electrically connected to each

other.

[132] The controller 40 may detect a temperature of the heat generating

element 273 in a state in which the heat generating element 273 is turned on

or off, and detect clogging of an air passage based on a temperature difference

value between a first detection temperature and a second detection

temperature among the detection temperatures of the heat generating element

273.

[133] For example, the first detection temperature may be a temperature

detected by the sensing element 274 immediately after the heat generating

element 273 is turned on, and the second detection temperature may be a

temperature detected by the sensing element 274 immediately after the heat

generating element 273 is turned off.

[134] As another example, the first detection temperature may be a lowest

temperature value during a period of time when the heat generating element

89731636.3

273 is turned on, and the second detection temperature may be a highest

temperature value during a period of time when the heat generating element

273 is turned on.

[135] Hereinafter, a method for detecting the amount of frost on the

evaporator 30 using the heat generating element 273 will be described in detail

with reference to the drawings.

[136] FIG. 9 is a flowchart showing a method of performing a defrost operation

by determining a time point when a refrigerator needs to be defrosted

according to an embodiment of the present disclosure, and FIG. 10 is a view

showing changes in a temperature of a heat generating element according to

the on/off of the heat generating element before and after frost on the

evaporator according to an embodiment of the present disclosure.

[137] In FIG. 10, (a) shows a change in temperature of the freezing

compartment and a change in temperature of the heat generating element

before occurrence of frost on the evaporator 30, and (b) shows a change in

temperature of the freezing compartment and a change in temperature of the

heat generating element after occurrence of frost on the evaporator 30. In the

present embodiment, it is assumed that a state before occurrence of frost is a

state after a defrosting operation is completed.

[138] Referring to FIGS. 9 and 10, in step S21, the heat generating element

27 is turned on.

[139] Specifically, the heat generating element 273 may be turned on in a

state in which a cooling operation is being performed on the storage

compartment 11 (e.g., freezing compartment).

89731636.3

[140] Here, the state in which the cooling operation of the freezing

compartment is performed may mean a state in which the compressor 60 and

the blowing fan 70 are being driven.

[141] As described above, when a change in the flow rate of the air increases

as the amount of frost on the evaporator 30 is large or small, the detection

accuracy of the sensor 260 may be improved. That is, when the change in the

flow rate of the air is large as the amount of frost on the evaporator 30 is large

or small, the amount of change in the temperature detected by the sensor 270

becomes large, so that the time point at the defrosting is necessary may be

accurately determined.

[142] Therefore, it is possible to increase the accuracy of the sensor only

when frost on the evaporator 30 is detected in a state in which air flow occurs,

that is, the blowing fan 70 is being driven.

[143] As an example, as shown in FIG. 11, the heat generating element 273

may be turned on at a certain time point S1 while the blowing fan 70 is being

driven.

[144] The blower fan 70 may be driven for a predetermined period of time to

cool the freezing compartment. In this case, the compressor 60 may be driven

at the same time. Therefore, when the blowing fan 70 is driven, the

temperature Ft of the freezing compartment may decrease.

[145] On the other hand, when the heat generating element 273 is turned on,

the temperature detected by the sensing element 274, that is, the temperature

Ht of the heat generating element 273 may increase rapidly.

89731636.3

[146] Next, in step S22, it may be determined whether the blowing fan 70 is

turned on.

[147] As described above, the sensor 270 may detect a change in

temperature of the heat generating element 273, which is changed due to air

of which the flow rate is changed according to the amount of frost on the

evaporator 30. Therefore, when no air flow occurs, it is difficult for the sensor

270 to accurately detect the amount of frost on the evaporator 30.

[148] When the blowing fan 70 is being driven, in step S23, the temperature

Htl of the heat generating element may be detected.

[149] Specifically, the heat generating element 273 may be turned on for a

predetermined period of time, and the temperature (Htl) of the heat generating

element 273 may be detected by the sensing element at a certain time point

in the state in which the heat generating element 273 is turned on.

[150] In the present embodiment, the temperature Htl of the heat generating

element 273 may be detected at a time point at which the heat generating

element 273 is turned on. That is, in the present disclosure, the temperature

immediately after the heat generating element 273 is turned on may be

detected. Therefore, the detection temperature Htl of the heat generating

element may be defined as the lowest temperature in the state in which the

heat generating element 273 is turned on.

[151] Here, the temperature of the heat generating element 273 detected for

the first time may be referred to as a"first detection temperature (Ht)".

[152] Next, in step S24, it is determined whether a first reference time T1 has

elapsed while the heat generating element 273 is turned on.

89731636.3

[153] When the heat generating element 273 is maintained in the turned-on

state, the temperature detected by the sensing element 274, that is, the

temperature Htl of the heat generating element 273 may continuously

increase. However, when the heat generating element 273 is maintained in the

turned-on state, the temperature of the heat generating element 273 may

increase gradually and converge to the highest temperature point.

[154] On the other hand, when the amount of frost on the evaporator 30 is

large, the flow rate of the air flowing into the bypass passage 230 increases,

and thus the amount of cooling for the heat generating element 273 by air

flowing through the bypass passage 230 increases. Then, the highest

temperature point of the heat generating element 273 may be set to be low by

the air flowing through the bypass passage 230 (see (b) of FIG. 10).

[155] 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 thus the amount

of cooling for the heat generating element 273 by air flowing through the

bypass passage 230 decreases. Then, the highest temperature point of the

heat generating element 273 may be set to be high by the air flowing through

the bypass passage 230 (see (a) of FIG. 10).

[156] In the present embodiment, the temperature of the heat generating

element 273 may be detected at a time point at which the heat generating

element 273 is turned on. That is, in the present disclosure, it can be

understood that the lowest temperature value of the heat generating element

273 is detected after the heat generating element 273 is turned on.

89731636.3

[157] Here, the first reference time T1 for which the heat generating element

273 is maintained in the turned-on state may be 3 minutes but is not limited

thereto.

[158] When a predetermined period of time has elapsed while the heat

generating element 273 is turned on, in step S25, the heat generating element

273 is turned off.

[159] As in FIG. 10, the heat generating element 273 may be turned on for

the first reference time T1 and then turned off. When the heat generating

element 273 is turned off, the heat generating element 273 may be rapidly

cooled by air flowing through the bypass passage 230. Therefore, the

temperature Ht of the heat generating element 273 may rapidly decrease.

[160] However, when the turned-off state of the heat generating element 273

is maintained, the temperature Ht of the heat generating element may

gradually decrease, and the decrease rate thereof is significantly reduced.

[161] Next, in step S26, the temperature Ht2 of the heat generating element

may be detected.

[162] That is, the temperature Ht2 of the heat generating element is detected

by the sensing element 273 at a certain time point S2 in a state in which the

heat generating element 273 is turned off.

[163] In the present embodiment, the temperature Ht2 of the heat generating

element may be detected at a time point at which the heat generating element

273 is turned off. That is, in the present disclosure, the temperature

immediately after the heat generating element 273 is turned off may be

detected. Therefore, the detection temperature Ht2 of the heat generating

89731636.3 element may be defined as the lowest temperature in the state in which the heat generating element 273 is turned off.

[164] Here, the temperature of the heat generating element 273 detected for

the second time may be referred to as a "second detection temperature (Ht2)".

[165] In summary, the temperature Ht of the heat generating element maybe

first detected at a time point S1 when the heat generating element 273 is

turned on, and may be additionally detected at a time point S2 at which the

heat generating element 273 is turned off. In this case, the first detection

temperature Htl that is detected for the first time may be the lowest

temperature in the state in which the heat generating element 273 is turned on,

and the second detection temperature Ht2 that is additionally detected may be

the highest temperature in the state in which the heat generating element 273

is turned off.

[166] Next, in step S27, it is determined whether a temperature stabilization

state has been achieved.

[167] Here, the temperature stabilization state may mean a state in which

internal refrigerator load does not occur, that is, a state in which the cooling of

the storage compartment is normally performed. In other words, the fact that

the temperature stabilization state is made may mean that the opening/closing

of a refrigerator door is not performed or there are no defects in components

(e.g., a compressor and an evaporator) for cooling the storage compartment

or the sensor 270.

89731636.3

[168] That is, the sensor 270 may accurately detect the amount of frost on

the evaporator 30 by determining whether or not temperature stabilization has

been achieved.

[169] In the present embodiment, in order to determine the temperature

stabilization state is achieved, it is possible to determine the amount of change

in the temperature of the freezing compartment for a predetermined period of

time. Alternatively, in order to determine the temperature stabilization state is

achieved, it is possible to determine the amount of change in the temperature

of the evaporator 30 for a predetermined period of time.

[170] For example, a state in which the amount of change in temperature of

the freezing compartment or in temperature of the evaporator 30 during the

predetermined period of time does not exceed 1.5 degrees may be defined as

the temperature stabilization state.

[171] As described above, the temperature Ht of the heat generating element

may rapidly decrease immediately after the heat generating element 273 is

turned off, and then the temperature Ht of the heat generating element may

gradually decrease. Here, it is possible to determine whether temperature

stabilization has been achieved by determining whether the temperature Ht of

the heat generating element decreases normally after decreasing rapidly.

[172] When the temperature stabilization state is achieved, in step S28, the

temperature difference AHt between the temperature Htl detected when the

heat generating element 273 is turned on and the temperature Ht2 detected

when the heat generating element 273 is turned off may be calculated.

89731636.3

[173] In step S29, it is determined whether the temperature difference AHt is

less than a first reference temperature value.

[174] Specifically, when the amount of frost on the evaporator 30 is large, the

flow rate of the air flowing into the bypass passage 230 increases, and thus

the amount of cooling for the heat generating element 273 by air flowing

through the bypass passage 230 may increase. When the amount of cooling

increases, the temperature Ht2 of the heat generating element detected

immediately after the heat generating element 273 is turned off may be

relatively low compared to a case where the amount of frost on the evaporator

30 is small.

[175] As a result, when the amount of frost on the evaporator 30 is large, the

temperature difference AHt may be small. Accordingly, it is possible to

determine the amount of frost on the evaporator 30 through the temperature

difference AHt.

[176] Here, the first reference temperature value may be 32 degrees, for

example.

[177] Next, when the temperature difference AHt is less than the first

reference temperature value, in step S30, a defrosting operation is performed.

[178] When the defrosting operation is performed, the defrosting device 50 is

driven and 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.

[179] On the other hand, instep S27, when the temperature stabilization state

is not achieved or, in step S29, when the temperature difference AHt is greater

89731636.3 than or equal to the first reference temperature value, the algorithm ends without performing the defrosting operation.

[180] In the present embodiment, the temperature difference value AHt may

be defined as a "logic temperature" for detection of frosting. The logic

temperature may be used as a temperature for determining a time point for a

defrosting operation of the refrigerator, and may be used as a temperature for

detecting clogging of an air passage, which is to be described later.

[181] Meanwhile, in the present disclosure, it may be possible to detect

whether the air passage of the refrigerator is clogged or a sensor failure occurs

by determining whether the temperature difference value between the first

detection temperature Htl and the second detection temperature Ht2 is out of

a normal range.

[182] Here, the clogging of the air passage may include at least one or more

of clogging of a passage through which cool air circulating inside the

refrigerator flows, that is, clogging of the cool air inflow hole 221 or the cool air

discharge hole 211 of the cool air duct 20 defining the heat-exchange space

222, clogging of the blowing fan 70 provided in the cool air duct 20, or clogging

of the bypass passage 230.

[183] The cool air inflow hole 221, the cool air discharge hole 211, the blowing

fan 70, and the bypass passage 230 may be clogged by frost due to

condensation of moisture contained in the air on the surface. As described

above, when the air passage is clogged by growth of frost, there is a problem

that air flow resistance is caused, and as a result, heat exchange efficiency of

the evaporator is reduced and power consumption is increased.

89731636.3

[184] Accordingly, the present disclosure is characterized in that the cause of

the clogging of the air passage of the refrigerator is diagnosed and appropriate

measures are taken accordingly.

[185] FIG. 11 is a flowchart schematically showing a method of detecting

clogging of an air passage of a refrigerator according to an embodiment of the

present disclosure.

[186] Referring to FIG. 11, in step S41, the heat generating element 273 is

operated for a predetermined time.

[187] Specifically, the heat generating element 273 may be turned on for a

predetermined time and then turned off. For example, the heat generating

element 273 may be turned on for 3 minutes.

[188] Next, instep S43, the controller 40 may detect a temperature of the heat

generating element 273 in a state in which the heat generating element 273 is

turned on or off.

[189] For example, the controller 40 may detect the temperature of the heat

generating element 273 immediately after the heat generating element 273 is

turned on and the heat generating element 273 is turned off.

[190] As another example, the controller 40 may detect the temperature of

the heat generating element 273 during a period of time when the heat

generating element 273 is turned on.

[191] Next, in step S45, the controller 40 may detect clogging of the air

passage based on a temperature difference value between the first detection

temperature that is the lowest value and the second detection temperature that

89731636.3 is the highest value, among detection temperatures of the heat generating element 273.

[192] The method of detecting the amount of frost on the evaporator 30

according to a temperature difference value between the first detection

temperature and the second detection temperature of the heat generating

element 273, that is, a logic temperature AHt has been described above.

[193] However, in the present embodiment, when the logic temperature AHt

has an abnormally large value, it may be determined that a failure has occurred

in the sensor 270.

[194] Although the defrosting operation is performed when the logic

temperature AHt is less than a reference value, it may be determined that the

air passage of the refrigerator has been clogged when the logic temperature

AHt is still kept low.

[195] In this case, the clogging of the air passage may mean that at least one

of the cool air inflow hole 221, the cool air discharge hole 211, the blowing fan

70, and the bypass passage 230 is clogged. In this case, it is difficult to solve

the clogging of the air passage. That is, when the clogging of the air passage

occurs, it is difficult to remove frost formed in the cool air inflow hole 221, the

cool air discharge hole 211, the blowing fan 70, and the bypass passage 230

even though the defrosting operation is performed. Accordingly, when it is

determined that the air passage is clogged, it may be immediately notified to

the user so that the clogging of the air passage may be resolved.

89731636.3

[196] FIG. 12 is a flowchart showing a detailed method for detecting clogging

of an air passage of a refrigerator according to an embodiment of the present

disclosure.

[197] Referring to FIG. 12, in step S51, a logic temperature AHt may be

updated. Here, updating the logic temperature AHt means that steps S21 to

S28 of FIG. 9 described above are performed again.

[198] Alternatively, update of the logic temperature may means may that

steps S21 to S28 of FIG. 9 described above are performed initially.

[199] Next, in step S52, the controller 40 may determine whether the updated

logic temperature AHt is less than the second reference temperature value. In

this case, the second reference temperature value may be greater than the

first reference temperature value. As an example, the second reference

temperature value may be 50 degrees, but is not limited thereto.

[200] Here, the reason to determine whether the updated logic temperature

AHt is less than the second reference temperature value is to determine

whether the updated logic temperature AHt is within a normal range. That is,

when the updated logic temperature AHt is not within the normal range, that is,

when the updated logic temperature AHt has an abnormally large value, it may

be determined that a failure has occurred in the sensor 270.

[201] For example, the cause of the failure of the sensor 270 may include a

case where a wire of the heat generating element 273 is short-circuited, a case

where a wire of the sensing element 274 is short-circuited, or a case where

the heat generating element 273 is frozen. In this case, the sensor 270 may

need to be repaired or replaced.

89731636.3

[202] Therefore, when the updated logic temperature AHt exceeds the

second reference temperature value, in step S53, the controller 40 may display

a failure of the sensor 270.

[203] Instep S54, the controller 40 may perform defrosting operation. That is,

when a failure occurs in the sensor 270, the defrosting operation may be

normally performed.

[204] When the updated logic temperature AHt is less than the second

reference temperature value, in step S55, the controller 40 may determine

whether the updated logic temperature AHt is less than a third reference

temperature value. In this case, the third reference temperature value may be

a value less than the second reference temperature value. As an example, the

third reference temperature value may be 45 degrees, but is not limited thereto.

[205] The reason to determine whether the logic temperature AHt is less than

the third reference temperature value may be to detect clogging of an air

passage of the evaporator 1.

[206] In the present disclosure, when one or more of the air passage of the

refrigerator 1, that is, the cool air inflow hole 221, the cool air discharge hole

211, the blowing fan 70, and the bypass passage 230 are clogged, the flow

rate or flow speed of air may be rapidly reduced, and as a result, the flow rate

of air flowing into the bypass passage 230 may be rapidly decreased.

Accordingly, since the flow rate of the air flowing into the bypass passage 230

is reduced, the temperature of the heat generating element 273 detected while

the heat generating element 273 is turned on may increase rapidly.

89731636.3

[207] According to the above-described principle, the fact that the updated

logic temperature AHt is measured as being very high may mean that at least

one or more of the cool air inflow hole 221, the cool air discharge hole 211, the

blower fan 70, and the bypass passage 230 are clogged.

[208] When the updated logic temperature AHt exceeds the third reference

temperature value, it may be determined in steps S56 and S57 whether the

updated logic temperature AHt exceeds the third reference temperature value

for the first time. When the updated logic temperature AHt exceeds the third

reference temperature value for the first time, in step S54, the controller 40

may performs defrosting operation.

[209] Alternatively, in steps S56 and S57, when the updated logic

temperature AHt does not exceed the third reference temperature value for the

first time, that is, when it is determined that clogging of the air passage has still

occurred, in step S58, the controller 40 may display the clogging of the air

passage and then perform defrosting operation.

[210] According to this configuration, it may be possible to inform a user of

the clogging of the air passage when the clogging of the air passage

continuously occurs, so that accurate diagnosis is possible and maintenance

and management are easy.

[211] On the other hand, when the updated logic temperature AHt is less than

the third reference temperature value, in step S59, the controller 40 may

determine whether the updated logic temperature AHt is less than a fourth

reference temperature value. In this case, the fourth reference temperature

value may be a value less than the third reference temperature value. For

89731636.3 example, the fourth reference temperature value may be 35 degrees, but is not limited thereto.

[212] When the updated logic temperature AHt exceeds the fourth reference

temperature value, that is, when the updated logic temperature AHt is less than

the third reference temperature value and is greater than or equal to the fourth

reference temperature value, the controller 40 may return to step S51 without

performing the defrosting operation.

[213] That is, when the updated logic temperature AHt is less than the third

reference temperature value and is greater than or equal to the fourth

reference temperature value, it means a state in which clogging of the air

passage occurs.

[214] Conversely, when the updated logic temperature AHt is less than the

fourth reference temperature value, in steps S60 and S61, the controller 40

may determine whether the updated logic temperature AHt exceeds the fourth

reference temperature value for the first time. When the updated logic

temperature AHt exceeds the fourth reference temperature value for the first

time, in step S62, the controller 40 may determine whether the updated logic

temperature AHt is less than the first reference temperature value.

[215] When the updated logic temperature AHt is less than the first reference

temperature value, in step S54, the controller 40 may determines that the

amount of frost on the evaporator 30 is large, and perform defrosting operation.

[216] When the updated logic temperature AHt exceeds the first reference

temperature value, the controller 40 may determine that the air passage has

89731636.3 not been clogged, and may return to step S51 without performing the defrosting operation.

[217] When the updated logic temperature AHt does not exceed the fourth

reference temperature value for the first time in step S60 and step S61, in step

S63, the controller 40 may determine whether the updated logic temperature

AHt has increased by "A" degrees or more from the previously updated logic

temperature.

[218] Here, the reason to determine whether the updated logic temperature

AHt has increased by "A" degrees or more from the previously updated logic

temperature is for determining whether the air passage is being progressively

clogged. That is, even when the air passage is not clogged completely, frost

growth in the air passage may be prevented fundamentally.

[219] For example, the case where the updated logic temperature AHt is

significantly higher than the previously updated logic temperature may mean

that the air passage is progressively clogged, and the amount of cooling of air

flowing through the bypass passage 230 is significantly reduced. That is, when

clogging of the air passage is continuously made, the air passage is completely

clogged, causing a problem in that air is not circulated.

[220] Therefore, when it is determined that the updated logic temperature AHt

has been increased by "A" degrees or more from the previously updated logic

temperature, in step S54, the controller 40 may perform a defrosting operation

to prevent the air passage from being clogged.

89731636.3

[221] When it is determined that the updated logic temperature AHt has not

been increased by "A" degrees or more from the previously updated logic

temperature, the controller 40 may proceed to step S62.

[222] Although it has been descried in the present embodiment that the first

detection temperature Htl may be a temperature detected by a sensing

element of the sensor immediately after the heat generating element is turned

on, and the second detection temperature Ht2 may be a temperature detected

by a sensing element of the sensor immediately after the heat generating

element is turned off, the present embodiment is not limited thereto.

[223] According to another embodiment, the first detection temperature Htl

and the second detection temperature Ht2 may be temperature values

detected while the heat generating element is turned on. For example, the first

detection temperature (Ht) may be a lowest temperature value during a

period of time when the heat generating element is turned on and the second

detection temperature (Ht2) is a highest temperature value during the period

of time when the heat generating element is turned on.

[224] Although embodiments have been described with reference to a

number of illustrative embodiments thereof, it will be understood by those

skilled in the art that various changes in form and details may be made therein

without departing from the spirit and scope of the invention as defined by the

appended claims. Therefore, the preferred embodiments should be considered

in a descriptive sense only and not for purposes of limitation, and also the

technical scope of the invention is not limited to the embodiments. Furthermore,

the present invention is defined not by the detailed description of the invention

89731636.3 but by the appended claims, and all differences within the scope will be construed as being comprised in the present disclosure.

[225] Many modifications will be apparent to those skilled in the art without

departing from the scope of the present invention as herein described with

reference to the accompanying drawings.

89731636.3

Claims (20)

[CLAIMS]

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

operating a heat generating element of a sensor unit disposed in a

bypass passage for a predetermined period of time, the bypass passage

allowing air flow to bypass an evaporator disposed in a heat-exchange space;

sensing a plurality of temperatures of the heat generating element in a

turned on state or turned off state; and

sensing clogging of an air passage in the heat-exchange space or a

failure of the sensor or an amount of frost on the evaporator based on a

temperature difference between a first temperature (Htl) that is a lowest value

and a second temperature (Ht2) that is a highest value among the sensed

plurality of temperatures of the heat generating element; and

performing a defrosting operation of the evaporator when a temperature

difference value between the first detection temperature (Htl) and the second

detection temperature (Ht2) is less than a first reference value.

2. The method of claim 1, wherein the first temperature (Ht) is a

temperature sensed by a sensing element of the sensor unit immediately after

the heat generating element is turned on.

3. The method of claim 1 or claim 2, wherein the second temperature (Ht2)

is a temperature sensed by a sensing element of the sensor unit immediately

after the heat generating element is turned off.

89731636.3

4. The method of any one of claims 1 to 3, wherein the first temperature

(Htl) is a lowest temperature value during a period of time when the heat

generating element is turned on.

5. The method of any one of claims 1 to 4, wherein the second

temperature (Ht2) is a highest temperature value during a period of time when

the heat generating element is turned on.

6. The method of any one of claims 1 to 5, wherein the refrigerator

comprises a cool air duct configured to define a heat-exchange space, and a

passage cover configured to cover the bypass passage so as to partition the

bypass passage from the heat exchange space,

wherein the bypass passage is disposed to be recessed in the cool air

duct.

7. The method of any one of claims 1 to 6, further comprising:

sensing an updated temperature difference between the first

temperature (Htl) and the second temperature (Ht2) after the defrosting

operation is completed, and

displaying a notification indicating a failure of the sensor unit when the

updated temperature difference exceeds a second reference value.

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8. The method of claim 7, wherein when the updated temperature

difference is less than the second reference value, the method further

comprises:

determining whether the updated temperature difference is less than a

third reference value, the third reference value being a value less than the

second reference value, and

displaying a notification indicating the clogging of the air passage in the

heat-exchange space when the updated temperature difference exceeds the

third reference value.

9. The method of claim 8, wherein the notification indicating the clogging

of the air passage further comprises one or more notifications indicating:

clogging of a cool air inflow hole of a cool air duct defining the heat

exchange space,

clogging of a cool air discharge hole of the cool air duct, or

clogging of a blowing fan provided in the cool air duct or clogging of the

bypass passage.

10. The method of claim 8 or claim 9, wherein when the updated

temperature difference value is less than the third reference value, the method

further comprises:

determining whether the updated temperature difference is less than a

fourth reference value, the fourth value being a value less than the third

reference value and greater than the first reference value, and

89731636.3 repeating the defrosting operation on the evaporator when the updated temperature difference is less than the fourth reference value.

11. The method of claim 10, wherein when the updated temperature

difference is less than the fourth reference value, the method further comprises:

determining whether the updated temperature difference has increased

by a predetermined value or more when compared to the temperature

difference before the temperature difference was updated, and

repeating the defrosting operation on the evaporator when the updated

temperature difference value has increased by a predetermined value or more

compared to the temperature difference value before the temperature

difference has been updated.

12. The method of claim 10 or claim 11, further comprising:

repeating the defrosting operation on the evaporator according to

whether the updated temperature difference is less than the first reference

value when the updated temperature difference value is not increased by a

predetermined value or more compared to the temperature difference value

before the temperature difference value has been updated.

13. A refrigerator comprising:

an inner case defining a storage space;

a cooling duct configured to guide flow of air to the storage space;

89731636.3 a heat exchange space defined between the inner case and the cooling duct; an evaporator disposed in the heat exchange space; a bypass passage configured to allow air flow to bypass the evaporator; a sensor unit including a heat generating element disposed in the bypass passage and a sensing element configured to sense a plurality of temperatures of the heat generating element; and a controller configured to sense clogging of an air passage in the heat exchange space or a failure of the sensor or an amount of frost on the evaporator based on a temperature difference between a first temperature

(Htl) that is a lowest value and a second temperature (Ht2) that is a highest

value among the sensed plurality of temperatures of the heat generating

element,

wherein the controller is configured to perform a defrosting operation of

the evaporator, when the temperature difference value between the first

detection temperature (Htl) and the second detection temperature (Ht2) is less

than a first reference value.

14. The refrigerator of claim 13, wherein the first temperature (Htl) is a

temperature sensed by the sensing element immediately after the heat

generating element is turned on, and

wherein the second temperature (Ht2) is a temperature sensed by the

sensing element immediately after the heat generating element is turned off.

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15. The refrigerator of claim 13 or claim 14, wherein the first temperature

(Htl) is a lowest temperature value during a period of time when the heat

generating element is turned on,

wherein the second temperature (Ht2) is a highest temperature value

during a period of time when the heat generating element is turned on.

16. The refrigerator of any one of claims 13 to 15, further comprising a

passage cover configured to cover the bypass passage so as to partition the

bypass passage from the heat exchange space,

wherein the bypass passage is disposed to be recessed in the cool air

duct.

17. The refrigerator of any one of claims 13 to 16, wherein the controller is

configured to sense an updated temperature difference between the first

temperature (Htl) and the second temperature (Ht2) after the defrosting

operation is completed,

wherein a notification indicating a failure of the sensor unit is displayed

when the updated temperature difference value exceeds a second reference

value.

18. The refrigerator of claim 17, wherein when the updated temperature

difference value is less than the second reference value, the controller is

configured to:

89731636.3 determine whether the updated temperature difference is less than a third reference value, the third value being a value less than the second reference value, and display a notification indicating the clogging of the air passage in the heat-exchange space when the updated temperature difference value exceeds the third reference value.

19. The refrigerator of claim 18, wherein the notification indicating the

clogging of the air passage further comprises one or more notifications

indicating:

clogging of a cool air inflow hole of a cool air duct defining the heat

exchange space,

clogging of a cool air discharge hole of the cool air duct, or

clogging of a blowing fan provided in the cool air duct or clogging of the

bypass passage.

20. The refrigerator of claim 18 or claim 19, wherein when the updated

temperature difference value is less than the third reference value, the

controller is configured to:

determine whether the updated temperature difference is less than a

fourth reference value, the fourth reference value being a value less than the

third reference value , and

repeat the defrosting operation of the evaporator when the updated

temperature difference value is less than the fourth reference value.

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